ISSNMEMOIRSOF THEFACULTY OF ENGINEERINGOSAKA CITY UNIVERSITY

VOL. 61
DECEMBER 2020

PUBLISHED BY THE
GRADUATE SCHOOL OF ENGINEERINGOSAKA CITY UNIVERSITY

0078－6659

This series of Memoirs is issued annually. Selected original works of the membersof the Faculty of Engineering are compiled in the first part of the volume. Abstracts ofpapers presented elsewhere during the current year are compiled in the second part. Listof conference presentations delivered during the same period is appended in the last part.
All communications with respect to Memoirs should be addressed to:
Dean of the Graduate School of Engineering
Osaka City University
3-3-138, Sugimoto, Sumiyoshi-ku
Osaka 558-8585, Japan
Editors
Eiji SHIKOH
Hayato NAKATANI
Masafumi MURAJI
Shigeyoshi NAKAJIMA
Kingo ARIYOSHI
Yuichiro NISHINO
Satoshi MIZUTANIMEMOIRS OF THE FACULTY OF ENGINEERINGOSAKA CITY UNIVERSITY
VOL. 61

DECEMBER 2020

CONTENTS
Regular Articles ·························································································· 1

Physical Electronics and Informatics
Electrical and Information Engineering
An Estimation of the Number of Users by Backoff Time Distribution with Frozen Backoff in
CSMA/CA
Koki SAMOTO, Ikuo OKA, and Shingo ATA ····················································

1

Urban Engineering
Urban Design and Engineering
Study on Pedestrian Traffic Flow in Crowded Conditions Using Mobile Location Data
Naotaka NISHIMURA and Nagahiro YOSHIDA ···············································

9

Abstracts of Papers Published in Other Journals ···········································

15

Mechanical and Physical Engineering
Mechanical Engineering ······································································· 17
Physical Electronics and Informatics
Applied Physics and Electronics ······························································ 22
Electrical and Information Engineering ····················································· 30
Applied Chemistry and Bioengineering
Applied Chemistry and Bioengineering······················································ 33

Urban Engineering
Architecture and Building Engineering ······················································ 52
Urban Design and Engineering ······························································· 55

List of Presentations at International Conferences ·········································· 65
Mechanical and Physical Engineering
Mechanical Engineering ······································································· 67
Physical Electronics and Informatics
Applied Physics and Electronics ······························································ 68
Electrical and Information Engineering ····················································· 70
Applied Chemistry and Bioengineering
Applied Chemistry and Bioengineering
Urban Engineering
Urban Design and Engineering······················································ 71·······························································

72

ISSN

MEMOIRSOF THEFACULTY OF ENGINEERINGOSAKA CITY UNIVERSITY――――――――
VOL. 61――――――――DECEMBER 2020

PUBLISHED BY THE
GRADUATE SCHOOL OF ENGINEERINGOSAKA CITY UNIVERSITY

0078－6659

An Estimation of the Number of Users by Backoff Time Distribution
with Frozen Backoff in CSMA/CA
Koki SAMOTO*, Ikuo OKA**, and Shingo ATA***(Received October 31, 2020)
Synopsis
Recently, with the increased demand for wireless communications, the degradation of communication efficiency
due to the concentration of connections to one of AP's has become a serious problem. In order to improve thecommunication efficiency, the number of users is an important parameter.
In this paper, an estimation method is proposed for the number of users using the probability distribution of backoff.
The probability distribution is derived considering frozen backoff. The number of users is obtained by the maximum
likelihood estimation with the derived probability distribution of backoff time.
Keywords: CSMA/CA, DCF, Backoff time distribution, Estimation of users, Frozen backoff

1.Introduction
In Recent years, the demand for wireless communication is increasing, and a wireless LAN is used widely in public
facilities, businesses, and homes. The wireless LAN employs CSMA/CA (Carrier Sense Multiple Access with
Collision Avoidance) as MAC (Medium Access Control) protocols. One of the features of CSMA/CA is the backoff
algorithm to avoid collisions, where a user sends a packet after a random delay time. New backoff algorithm areproposed to improve network performance1)2).
In the wireless LAN, users communicate with other users by a relay access point (AP). When an access isconcentrated on the same AP, the collision probability increases and the communication efficiency decreases. An
algorithm was proposed that maximizes the minimum throughput of a node and selects the best AP3). An AP
selection and a load balancing are discussed to improve throughput based on the number of users connected to the
AP4).
The estimation of number of users is presented by an extended Kalman filter with measured number of collisions5).
The maximum likelihood estimation is applied to the probability distribution of backoff time in order to obtain thenumber of users6). However, a frozen backoff time is not included in the analysis, which yields misestimation resultsin the frozen backoff environments.
* Student, Master Course of Department of Electrical and Information Engineering** Professor, Department of Electrical and Information Engineering*** Professor, Department of Electrical and Information Engineering－1－

In this paper, an estimation method is proposed for the number of users using probability distribution of backoff
considering frozen backoff. The analysis method is presented to derive the probability distribution of backoff timewith frozen backoff in time axis. For 2 users, the Markov state transition diagram is considered for all possiblecombinations of backoff time, and the relation at time 𝑡𝑡 𝑡 1 and time 𝑡𝑡 is derived. For 3 users or more, a time

axis analysis is extended by assuming statistical independence of probability distribution in the target user and otherusers. As a result, the calculation time can be reduced from the exponential increase to the linear increase, as thenumber of users increases. Then, the number of users is obtained by the maximum likelihood estimation using theprobability distribution of backoff time. Numerical results for the number of users demonstrate the estimation
performance in the frozen backoff environments.
2.CSMA/CAIn CSMA/CA, each user trying to transmit a packet performs carrier sense and checks the usage status of thechannel. After the channel becomes idle for the DIFS (DCF Inter Frame Space), the user generates a random number
within the specified CW (Contention Window) range, and the backoff time is determined. In IEEE802.11, backoff
time follows as� � 𝑟𝑟 � 𝑠𝑠

where 𝑟𝑟 is a random integer generated from a uniform distribution of �0, 𝐶𝐶𝐶𝐶 𝐶 1�, and 𝑠𝑠 is a slot time. 𝐶𝐶𝐶𝐶 isan integer between 𝐶𝐶𝐶𝐶��� and 𝐶𝐶𝐶𝐶��� , and determined by

𝐶𝐶𝐶𝐶 � 𝐶𝐶𝐶𝐶��� � 2�

where 𝑚𝑚 is a number of collisions. The determined backoff time decreases for each slot time in the case of channel

idle, and when it reaches 0, the user transmits a packet. In the case of channel busy, the backoff time is frozen andcarried over to the next transmission opportunity.

Figure 1: Example of packet transmission in CSMA/CA－2－

Fig.1 shows an example of packet transmission in CSMA/CA. Users "A", "B" and "C" are attempting to transmit
a packet to the AP. In this paper, "X" denotes the user, and X denotes a random variable of backoff slot of user "X".
After each user is idle for DIFS, it uses a random number generator to set a backoff time. It is assumed that thebackoff time's are set to 6 ∙ 𝑠𝑠 for user "A", 2 ∙ 𝑠𝑠 for user "B", and 3 ∙ 𝑠𝑠 for user "C". User "B" with the shortest
backoff time transmits a packet first. After the reception of the packet is completed, the AP sends an ACK frame

after SIFS, and the packet transmission is completed. While user "B" is using the channel, users "A" and "C" freeze
the decrease in backoff time. The frozen backoff time's are carried over to the next transmission opportunity. The

backoff time is set again for user "B", and the same process is repeated.
3.Backoff analysis
In this section, the probability distribution of backoff time 𝑥𝑥 of transmitted user with frozen backoff is derived intime axis. A window size is set to 15, and the backoff stage is not considered.

An illustrative example of the proposed time axis analysis for 𝑁𝑁 = 2 is shown in Fig.2 (a). At time 𝑡𝑡 𝑡 1, it isassumed that the backoff time's are set to 7 ∙ 𝑠𝑠 for user "A" and 4 ∙ 𝑠𝑠 for user "B". At time 𝑡𝑡, user "A" is set to3 ∙ 𝑠𝑠, which has been frozen, and user "B" is reset to 𝑥𝑥 𝑥𝑥𝑥(𝑥𝑥: [0, 1, ⋯ , 𝐶𝐶𝐶𝐶 𝐶 1]). For all possible backoff slot
combinations, the relation between time 𝑡𝑡 𝑡 1 and time 𝑡𝑡 is expressed by(�)

where 𝑃𝑃�,� is the occurrence probability of the combination of backoff slots of users "A" and "B" at time 𝑡𝑡, and(�)

Iterative calculations are executed for 𝑃𝑃�,� until the steady state is obtained. The results of the probability

distribution of observed backoff is shown by the solid line 𝑁𝑁 = 2 in Fig.3 (a).

Fig.2 (b) shows the time axis analysis when the number of users 𝑁𝑁 is 3 or more. The row represents the numberof backoff slots for the target user, and the column represents the minimum number of backoff slots for the other

𝑁𝑁 𝑁 1 users. We assume the statistical independence among probability distributions. When the number of users

is 3, at 𝑡𝑡 = 0, the element of row is a random variable C for user "C" which follows a uniform distribution, and theelement of column is given by the probability distribution of the minimum value of the uniform distribution of two
users "A" and "B", min (A, B) where A and B denote backoffs for user "A" and "B" respectively. The distributionof min(A, B) is derived by the distributions of A and B7). At 𝑡𝑡 = 1, the row is given by a backoff C1' which is a

result of min(A, min(A, B)) of 𝑡𝑡 = 0. The column is given by min(C2', C3'), where C2' and C3' have the independent

identical distribution as that of C1'. Similarly, when the number of users is 4, at 𝑡𝑡 = 0, the row is given by a uniform

distribution of user "D", and the column is given by the probability distribution of the minimum value of the uniform
distribution of three users, min (A, B, C). At 𝑡𝑡 = 1, the row is a backoff D1', which is a result of min(D, min(A, B,C)). The column is obtained by min(D2', D3', D4'), where D2', D3' and D4' have the independent identical distribution－3－

(a) 𝑁𝑁 = 2(b) 𝑁𝑁 � 3

Figure2: Illustrative example of the proposed time axis analysis－4－as that of D1'. For 𝑁𝑁 � 5, the backoff distribution of transmitted user is derived as well as the cases of 𝑁𝑁 = 3 and4. Numerical calculations are executed until the steady state is obtained. The probability distributions of observed
backoff for 𝑁𝑁 � 3 is shown by solid line in Fig.3 (a) and Fig.3 (b).

As a result, the calculation time can be reduced from the exponential increase to the linear increase as the numberof users increases. The simulation results are also depicted in Fig.3 (a) and Fig.3 (b). The analytical results have agood coincidence with the simulation results, and the validity of the proposed time axis analysis.

(a) 𝑁𝑁 = 2, 3, 4, 5(b) 𝑁𝑁 = 5, 10, 15, 20

Figure 3: The probability distribution of observed backoff－5－4.Estimation of the number of users
The number of users is obtained by the maximum likelihood estimation using the probability distribution of theobserved backoff derived in Section III. For the number of users, 𝑁𝑁, the likelihood function 𝐿𝐿(𝑁𝑁) is given by
where 𝑥𝑥� is the number of backoff slots observed at time 𝑖𝑖, 𝑝𝑝� (𝑥𝑥� ) is the probability of 𝑥𝑥� when the number of� is given byusers is 𝑁𝑁. The estimated number 𝑁𝑁

Fig.4 shows the estimation results for 𝑁𝑁 = 5, 10, 15, 20. The number of observations or samples is 2000. When

𝑁𝑁 = 20, it is estimated from 17 to 24. As 𝑁𝑁 is decreased, the estimation accuracy is improved, and when 𝑁𝑁 = 5,
there is no estimation error. Fig.4 is compared with the results of Ref.8) to confirm with the validity of the proposed

method. It is found that estimation results of the proposed method and Ref.8) have a good coincidence, while thebackoff distribution is given by computer simulations in Ref.8).

Figure 4: Estimation results for the number of users
5.Conclusions
In this paper, an analysis method has been presented for the probability distribution of backoff time with frozen
backoff in time axis. For 2 users, the Markov state transition diagram for all possible combinations of backoff times
gives the relation of distribution at time 𝑡𝑡 𝑡 1 and time 𝑡𝑡. For 3 users or more, a time axis analysis has been

extended by assuming statistical independence of probability distribution in the target user and other users. The
number of users has been estimated by maximum likelihood estimation using the probability distribution of backoff
time. The estimation result has been shown to confirm the validity the proposed method.

－6－6.References1)

Nah-Oak Song, Byung-Jae Kwak, Jabin Song, and Leonard E.Miller, ''Enhancement of IEEE 802.11
Distributed Coordination Function with Exponential Increase Exponential Decrease Backoff Algorithm,'' The
57th IEEE Semiannual Vehicular Technology Conference 2003, VTC 2003-Spring.IEEE, vol.4, pp.2775-2778,
2003.

2)

Xinghua Sun and Lin Dai, ''A Comparative Study of Quadratic Backoff and Binary Exponential Backoff inIEEE 802.11 DCF Networks,'' 2011 45th Annual Conference on Information Sciences and Systems, pp.1-6,
2011.

3)

Fengyuan Xu, Xiaojun Zhu, Chiu C. Tan, Qun Li, Guanhua Yan, and Jie Wu, ''SmartAssoc: Decentralized
Access Point Selection Algorithm to Improve Throughput,'' IEEE transactions on Parallel and distributed
systems, 24(12), 2482-2491.

4)

Uferah Shafi, Muhammad Zeeshan, Naveed Iqbal, Nadia Kalsoom, and Rafia Mumtaz, ''An OptimalDistributed Algorithm for Best AP Selection and Load Balancing in WiFi,'' pp.65-69, 2001.

5)

Giuseppe Bianchi and Ilenia Tinnirello, ''Kalman Filter Estimation of the Number of Competing Terminals in
an IEEE 802.11 network,'' Proc. IEEE International Conference on Computer Communications 2003, vol.1-3,
pp.844-852, 2003.

6)

Norihiro Matsumoto, Ikuo Oka, and Shingo Ata, ''Number of Users Estimated by Statistics of Random Backoff
Time in WiFi Networks,'' Proc. RISP International Workshop on Nonlinear Circuits, Communications andSignal Processing, pp.267-270, 2018.

7)

A.Papoulis, Probability, Random Variables, and Stochastic Processes, Tokyo: McGraw-Hill Kogakusha,
pp.193, 1965.

8)

Norihiro Matsumoto, Ikuo Oka, and Shingo Ata, ''Estimation of Number of Users by Backoff Distribution with
Frozen Backoff in RLAN," The 41st Symposium on Information Theory and its Applications (SITA2018), 2018.

－7－

Study on Pedestrian Traffic Flow in Crowded Conditions Using Mobile Location Data
Naotaka NISHIMURA* and Nagahiro YOSHIDA**(Received November 19, 2020)

Abstract
In recent years, in Japan, the number of incidents involving large crowds has been increasing for several
reasons, including the increase in the number of such time-intensive events as sports events and concerts, theincrease in the number of tourists, and the paralysis of traffic functions caused by natural disasters. However,
the increasing sophistication of information and communication technologies and smart phones has increased
the technological possibilities and improved crime prediction systems, leading to the development ofpedestrian agent simulations and the analysis of crowd conditions using big data. However, there is still a lackof knowledge on crowd control at the micro level of events, such as fireworks displays and disasters. The
purpose of this study was to gain new knowledge on how to understand and control crowd behavior at eventsby analyzing mobile location data obtained from smartphones.
KEYWORDS: crowd behavior, mobile location data, K–V scatter map
1. Introduction
In recent years, the number of crowd incidents has increased because of an increase in the number of timeintensive events, such as sports and concerts, as well as the paralysis of traffic functions during natural disasters.
Around the world, there have also been such crimes as mobbing and molestation in crowds, such as the sexualassault at the Etoile Arc de Triomphe during the 2018 soccer World Cup celebrations and the light truck
incident at Shibuya Halloween 2018.
However, because of the sophistication of information and communication technology, in many countries,
pedestrian simulation and crowd analysis using big data have been conducted. In Japan, the prediction of crowd
behavior by simulation1), the analysis of crowd wave phenomena2), simulations of GNSS availability forlocation estimation3), and map matching of pedestrian trajectories using GPS and PDR4) have been conducted,
but there is still a lack of knowledge on the observation of crowd behavior in the pedestrian space and on
crowd control and response in the event of a disaster.
Therefore, in this study, the target elements were classified as the direction of the crowd, walking speed,density, and spatial conditions. Psychological conditions were excluded. Mobile location data obtained fromsmartphones were used to gain basic knowledge about pedestrian traffic flow under crowding conditions
during events.
2. Methods of analysis
2.1 Target events
The target events were Halloween in Shibuya and Luminarie in Kobe. By observing and analyzing eventswith different characteristics (Table 1), one can understand the characteristics of crowd behavior anddifferences in pedestrian traffic flow control methods.
2.2 Analysis methods and flow
The velocities and densities obtained from the field survey results and mobile location data were compared.
“Crowding” was defined as a state of high density and reduced speed to understand the characteristics ofpedestrian traffic flow that differ from event to event and crowding conditions under high density (Figure 1).
* Student, Master Course of Department of Urban Design and Engineering** Associate Professor, Department of Urban Design and Engineering－9－

Table 1. Characteristics of target events
Event
Target Location
Area covered
Number of mobile deta acquired
Number of participants [per day]Spatial Conditions
Crowd movement conditions

Shibuya Halloween“Shibuya Scramble Crossing~Around Center Street”
Approx.0.12 ㎢
12,889 units“No organizer, unknown.
(Estimated 10 to 1 million people)”
Streets and Intersections
No guidance,only Center Street isone direction in congestion

Kobe Luminarie“Motomachi Higashi Yuenchi”
Approx.0.5 ㎢
39,445 units“Approx.542,000
Streets and Squares
One direction with guidanceFig. 1. Flow analysis
2.3 Outline of the field survey
A follow-up survey was conducted to understand the walking speed of people on the day of the event. In thefollow-up survey, pedestrians were followed along the set course, and the speed of each route was measured
every hour — five times for the Shibuya Halloween and twice for the Kobe luminarie. (Figaure 2,3)

Fig. 2. Route map for Halloween in Shibuya－10－

Fig. 3. Path of Kobe Luminarie
2.4 Mobile location data
The mobile location data used are the location information collected from the GPS of a smartphone with a
specific app installed, with the age and gender of the user being kept secret, and provided by Agoop as point
data. The information includes longitude and latitude, direction of movement, and speed.
2.4.1 Average transit speed analysis for each link path in the data
Pedestrian routes were set up for each event, and mobile location data at the time of the event were analyzed
for the average hourly transit speed of each link using the Mobmap human flow analysis software.
2.4.2 Comparison of density and velocity relationships before and after the event
Using mobile location data observed on an hourly basis, point densities and velocities were aggregated hourlyin 10-m meshes of the target site and compared before and after the event.
3. Results of the field survey and comparison of speed data
The results of the follow-up survey were compared with the mobile data, which were determined to bepedestrians based on the speed (0 < speed ≤ 2.5) when passing through each route during the event. For Shibuya
Halloween, the averages were similar except for route D.(Figure 4)
However, for the Kobe Luminarie, the average speed was higher for all routes in the follow-up survey results
than for the data, and the average speed for Kobe Luminarie was higher than that for Shibuya Halloween. Thisis because the entire route of the Kobe Luminarie is unidirectional, and it is influenced by the spaciousness of
the induction routes and the age range of the participants. Next, the intervals of variation were compared using
Tables 2 and 3. In the Shibuya Halloween, the value of path A is small (Table 4). This may be because themovement of the crowd was unified to one way only for path A. In addition, the significant decrease in thestandard deviation of path F after 7:00 p.m. was caused by the one-way flow of path A (E), which caused abackflow of participants who tried to reverse the flow of path A and a stagnation of participants who walked
along path A near the start of path F.
As a result, the effect of the constant movement of the crowds was considered as a numerical value. In the
Kobe Luminarie, the low values of J and K in Table 3 are considered to result from the effect of constant crowd
movement at the highest density near the event destination. The results in Tables 2 and 3 show that the data
had a large variation, even when crowd movements were unified, as in Kobe Luminarie.

－11－

Fig. 4. Speed verification results for each link path at each event

Standard deviation

Table 2. Standard deviation of Shibuya Halloween speed data bytime and route

5:00 p.m.

PathwayA(E)0.476

PathwayB
0.819

PathwayC
0.697

PathwayD
0.452

PathwayF
1.105

PathwayG
0.793

PathwayH
0.808

6:00 p.m.

0.428

1.098

0.585

0.592

0.702

0.577

0.486

7:00 p.m.

0.363

0.443

0.55

0.528

0.183

0.565

0.454

8:00 p.m.

0.422

0.473

0.594

0.501

0.059

0.588

0.34

9:00 p.m.

0.269

0.136

0.729

0.684

0.059

0.494

0.649

10:00 p.m.

0.5

0.938

0.737

0.416

0.006

0.552

0.458

11:00 p.m.

0.329

0.479

0.372

0.215

0.331

0.496

0.405

Mean standard deviation

0.398

0.627

0.609

0.49

0.35

0.581

0.514

Table 3. Standard deviation of speed data by time and route in Kobe LuminarieStandard
deviation

PathwayA

PathwayB

PathwayC

PathwayD

PathwayE

PathwayF

PathwayG

PathwayH

PathwayI

PathwayJ

PathwayK

6:00 p.m.

0.554

0.377

0.454

0.773

0.601

0.471

0.331

0.332

0.354

0.462

0.325

7:00 p.m.

0.472

0.334

0.404

0.447

0.469

0.588

0.426

0.545

0.387

0.299

0.282

8:00 p.m.

0.478

0.512

0.458

0.469

0.428

0.458

0.557

0.439

0.479

9:00 p.m.

0.557

0.454

0.679

0.371

0.211

0.412

0.465

0.402

0.387

Mean
standard
deviation

0.515

0.419

0.498

0.475

0.349

0.437

0.441

0.4

0.368

0.61

0.535

－12－

4. Comparison of pedestrian traffic flow analysis and K–V scatter plots for each event
The K–V scatter plots were used to compare the normal data and the data at the target event by event. In Kobe,
the dots with K > 3.0 in Fig. 5 are the highest density symbols in Fig. 7, i.e., people in the luminary venue.
Figure 7 shows the result of extracting the points with K ≤ 0.5 and V ≤ 0.5, as shown in Fig. 5. Because mostof the points in Fig. 5 are not on the induction path, these points are mostly nonparticipants, while the points
on the K–V line are mostly on the induction path and are considered to be points of the event participants.
Thus, it was possible to capture the strict division of event participants and nonparticipants by security on theK–V scatter diagram.
In the Shibuya area, points with K ≤ 1.5 and V ≤ 0.5 were extracted, and the above points were sparsely
distributed throughout the entire area except for the high-density area (Fig. 6,8). In the normal case, the points
0 ≤ K ≤ 0.5 and 0.5 ≤ V ≤ 2.5 on the scatterplot flowed around the 0.5 ≤ K ≤ 1.5 and V ≤ 0.5 area. Therefore,
it was found that most people walking at low speed, even at low density, during the Shibuya Halloween tended
to congregate at places where there were crowds of people to a certain extent.

Fig. 5. Kobe Luminarie K–V scatter map
Fig. 6. Shibuya Halloween K–V scatter map (K ≦ 3)

Fig. 7. Point extraction for Kobe Luminarie (K ≤ 0.5 and V ≤ 0.5)

－13－

Fig. 8. Point extraction for Shibuya Halloween (K ≤ 1.5 and V ≤ 0.5)
5. Conclusions
The variability of the speed data was found to be relatively small when the movement of the crowd was
unified or when retention was occurring. On the other hand, the variability of speed data in the whole data
made us feel the limitation of the current accuracy. By creating the K-V scatter diagram, we found that many
people walked at a lower speed at Shibuya Halloween than in normal times, and that people tended to gather
at places with a certain amount of crowds. In Kobe Luminarie, the participants and non-participants werestrictly separated by security. Thus, it was confirmed that it was possible to roughly understand the pedestrian
traffic flow during the event.
In this study, we were able to capture the overall movement of people at the time of the event in an aggregate
manner from the entire data, such as the variability of the entire data and the K-V scatter diagram, but we were
not able to grasp the movement of each individual in detail. In the future, we would like to seek a method ofanalyzing pedestrian behavior and crowd behavior from mobile location data to better understand pedestrian
traffic flow during events and disasters, and to gain new knowledge on how to control it.
6. References
T. Sato and T. Maruyama: Spatio-temporal analysis of smartphone-type migration survey data using kernel
density estimation method, Journal of Urban Planning, Vol. 51 (2016)2) M. Kajiji and A. Kitago: Study on crowd wave phenomenon under high-density crowd congestion leading
to pedestrian accidents, Proceedings of the Japan Society for Community Safety, No.17 (2012)3) S. Kamijo: Possibility of GNSS based Self-localization in Urban Canyon for Automated Vehicles, ICCVE2014 Summit Session S3, November 4 2014, Vienna (2014)
4) Dailin Li and Yanlei Gu, S. Kamijo: Smartphone Based Lifelog with Meaningful Place Detection, 2018
IEEE International Conference on Consumer Electronics (ICCE), Las Vegas (2018)
1)

－14－

Abstracts of Papers
Published in Other Journals

Mechanical and Physical Engineering
Mechanical Engineering
Color of Cooked Rice to Improve Appetite for Elderly
Pantakan SUKONTEE, Chanprapha PHUANGSUWAN, Hiroyuki IYOTA, Hideki SAKAI and Mitsuo
IKEDA
Proc. of the 5th Asia Color Association Conference, Nagoya, Japan, Nov.29 - Dec.2, pp.39-43 (2019).
In the next few years, we will step into the aging society completely and many changes will take place withaging. The most common problem in the elderly is anorexia, they get bored to eat any foods. To improve thissituation we hypothesized that if we change the color of rice changes from white to some other color byherbs such as butterfly pea, yellow by turmeric, red by roselle, green by pandanus leaf. Four chromatic colors
and plus white rice were prepared to be presented by LCD display. In each of color rice, we changed thesaturation by using Adobe Photoshop from the original color that was measured directly from real rice. Threesteps of higher saturation were added to the original color and three steps of lower saturation were added tothe original color. Finally, the total stimuli were 25 pictures. The preference questionnaire was “like” and“dislike” with scale 3 to -3, meaning like or dislike. We found that Thai elderlies preferred no vivid color ofrice in red, yellow, green and blue. Japanese elderlies mostly preferred white color of rice and showed asmall preference for red and yellow color by the reason that Japanese are familiar with the red and yellow
rice for their daily life.
Device Independent Simultaneous Lightness Contrast
Saran CHANTRA, Mitsuo IKEDA, Hideki SAKAI, Hiroyuki IYOTA and Chanprapha PHUANGSUWAN
Proc. of the 5th Asia Color Association Conference, Nagoya, Japan, Nov.29 - Dec.2 pp.181-185 (2019).
The simultaneous lightness contrast phenomenon was investigated with four different devices; a paper
stimulus, a two - rooms arrangement, a display, and a projector. Luminances of the central gray patch andsurround were made equal among the devices. Except the paper stimulus the strength of SLC was aboutsame among other devices to imply device independent SLC.
Measurement of Wet Colors of Bricks and Gravels by Using A Non-Contact Colorimetric System with
Dome Illumination
Mai ISOMI, Hideki SAKAI, Tsugumichi WATANABE and Hiroyuki IYOTA
Proc. of the 5th Asia Color Association Conference, Nagoya, Japan, Nov.29 - Dec.2, pp.426-431 (2019).
We measured the color changes of some garden components such as bricks and gravels from completely wet
to completely dry. Various colored bricks and gravels are sometimes used to decorate gardens. They easilychange color when they become wet. Therefore, it is helpful to know their wet colors for designing garden
scenery on a rainy day. In this experiment, beige, red and brown bricks were prepared, and white, red andgreen gravels were prepared. We immersed them under water for 30 minutes (completely wet condition).
Then, we took them from water, and measured their color changes when drying at various intervals. To
measure the colors, a non-contact colorimetric system with dome illumination was used. It consists of ahemispherical dome illumination and movable light traps. The dome illumination makes it possible to obtainthe unshaded images of rough surfaces of bricks and gravels. Without a light trap, however, the unshaded
images are specular componentincluded (SCI). With a light trap in one position, a part of the image becomes
specular componentexcluded (SCE). When the light trap is moved to another position, another part of theimage becomes SCE. Then, after moving the light traps all over the inner surface of the dome, all parts of the
SCE image are obtained and can be merged into a complete SCE image.
Evaluation Automatization of 2D-Image Recording System for Analysis of Change in Food
Appearance using Dome Illumination with Digital Camera
Aya HIROUCHI, Hiroyuki IYOTA, Mai ISOMI, Hiroyuki YAMAMOTO and Hideki SAKAI
Proc. of the 5th Asia Color Association Conference, Nagoya, Japan, Nov.29 - Dec.2, pp.462-465 (2019).
The appearance of food, including its surface color and glossiness, is an important factor in the evaluation ofquality. In general, the parameters associated with appearance change with time due to water evaporation andthe chemical reactions that occur during thermal processing, drying, storing, and mundane exposure. To
evaluate these parameters, quality control of food and process optimization is necessary. There are several－17－

available instruments for the measurement of the color and glossiness of flat and dry material surfaces.
However, these tools are not suitable for the characterization of the appearance of food due to the combined
effects of the roughness and moisture of food surfaces. Therefore, we have developed a device for thecontactless measurement of color and glossiness using a digital camera and a dome-shaped illumination
device. This instrument facilitates the acquisition of color images via specular component included (SCI) andexcluded (SCE) modes for subsequent analysis with/without the shading of a region of the dome-shaped
illumination. In this investigation, we installed an automatic control system for the illumination device tocapture the SCE and SCI images for long-duration monitoring. Electrical components were also installed tomeasure the temperature, humidity, and weight of food. The developed instrument facilitates the acquisitionof images without the requirement of a human operator, while analyses of the color and glossiness changewith time. Important experimental data can be obtained using this system, such as the effect of foodappearance change on the process conditions.
Model Description on the Interface Deformation after the Release of the Pinned Contact Line
Takahiro ITO (Chubu Univ.), Souichiro FUJII (Nagoya Univ.), Tatsuya TSUNEYOSHI (Nagoya Univ.),
Yoshiyuki TSUJI (Nagoya Univ.), Kenji KATOH and Tatsuro WAKIMOTO
Japanease Journal of Multiphase Flow, Vol. 34, No. 1, pp. 231-242 (2020) (in Japanese).
Contact line can be easily stuck (pinned) on the defects or boundary of the different wettability regions. The
contact line remains to be trapped until the contact angle increases beyond the advancing angle or decreases
below the receding angle. Once such condition is satisfied, the contact line is released from the trapping site
and rapidly proceeds or recedes with the contact angle changing toward the equilibrium contact angle. In thisstudy theoretical description on the contact line motion and the contact angle after the release from the stuckcondition at the groove edge is developed. The normal stress balance and the corresponding flow fieldadjacent to the surface are expressed under Stokes approximation. Since the interface deformation was
limited within a certain distance from the solid surface, referred as ‘boundary layer’, the equation on thenormal stress balance equation was solved with the boundary condition at the contact line and the outerboundary of the boundary layer. The results numerically obtained were compared with the experimental data,
showing fairly good agreement between them.
Removal of Micrometer-Sized Particles on a Solid Wall by High-Speed Impinging Air Jet
Tatsuro WAKIMOTO, Akihiro TAKAHASHI, Kazuhiko SOEMOTO (Shinko Co. Ltd.) and Kenji KATOH
Advanced Experimental Mechanics, Vol. 5, pp. 57-62 (2020).
In this study, a cleaning device to remove micron-sized particles on a solid surface by an air jet is developed.
This device has a special nozzle containing a triangular cavity to add high intensity turbulence to the air jet,and the air jet impinges on the solid surface removing the particles. Assuming the removal of a sphericalparticle by rotational movement, we performed numerical simulation of the flow field in the cleaning device
and estimated the rotational moment induced by drag force from the numerical results. As the results of thenumerical analysis for modified nozzle shapes, it was clarified that the minimization of slit length reducedpressure loss in the slit and increased the velocity of near-wall flow. This effect enhanced the removal
moment and improved removal performance.
Measuring Method of Surface Tension of Liquid
Tatsuro WAKIMOTO and Kenji KATOH
Journal of the Japanese Society for Experimental Mechanics, Vol. 20, No. 2, pp. 139-141 (2020) (inJapanese).
In order to measure the surface tension with enough accuracy and reproducibility, experimenter must beversed in the measuring method and be careful in preparing and storing the test liquids. In this paper, we
explain typical four measurement methods of surface tension: capillary-rise method, Wilhelmy method,
sessile drop method, and pendant drop method. Although legacy capillary-rise method is quite simple,
accuracy is not enough. Wilhelmy method is the most popular and well-balanced technique between
moderate accuracy of ±0.2 mN/m and operator’s effort. Sessile and pendant drop methods are capable ofhigh-accuracy measurement below 0.1 mN/m in return for precise image data processing. Technicalknow-how and cost reduction of these methods are also described in this paper.
Movement Control of Falling Droplet on a Plate using Micro-Wrinkle
Kenji KATOH, Eriko SATO, Shin’ya YOSHIOKA (Osaka Electro-Communication University) and Tatsuro
WAKIMOTO－18－

Chemical Industry, Vol. 71, No. 9, pp. 562-566 (2020) (in Japanese).
In this study, we consider the control of a liquid droplet movement rolling down on an inclined plate withgravitational force using a micro-wrinkle on a wall. The micro-wrinkle was manufactured by the buckling ofa thin polymer film (poly(N-vinylcarbazole), PVK) on a base polymer (poly(vinyl chloride), PVC). The PVC
was stretched once and then PVK (~ 100-nm thickness) was spin-coated on the surface of the base polymer
at ambient temperature. When the strain was released in a thermostatic chamber heated above the glasstransition temperature of PVC, a two-dimensional micro-wrinkle having a wavelength of several
micrometers was formed on the surface. The advancing and receding contact angles were measured indirections parallel and perpendicular to the wrinkle. It was observed that there were several degrees ofcontact angle anisotropy. When the droplet was set on the wrinkle surface inclined at 45° to the gravitational
force, the direction of droplet movement could be changed by ~ 20° from the gravitational direction. The
deflection angle was estimated from a theoretical model with the principle of minimum work of the contactline.
Development of an Archery Robot for the Selection of Arrows
Masashi OHARA, Naoki KAWASAKI, Jun NAKAHAMA, Yogo TAKADA and Hitoshi WATANABE
Proc. the 13th Conference of the International Sports Engineering Association, Online, June 22-26, 49, 115,
7 pages (2020).
The appropriate selection of arrows in the sport of archery is important to the achievement of high-quality
results. In this regard, a shooting machine that is compatible with the wide variety of available bows andarrows is necessary. However, bow strength and arrow length vary among different athletes. It is also
important to develop a shooting machine that reproduces the movement of the right fingers that releases anarrow, and the forward jump of a bow after shooting an arrow. In this study, a shooting machine wasdeveloped that considered these factors. Its efficacy was examined in terms of its ability to determine thecharacteristics of each arrow, and to distinguish between normal and flawed arrows. Based on theexperimental results, we identified the factors that affected the shooting accuracy of arrows. In addition, thedeveloped shooting machine was able to distinguish between normal and flawed arrows.
Temperature Dependence of the Growth Process of Grain Boundary Steps Formed on Ultra-precision
Finished Polycrystalline Copper Surface
Tatsuya USUKI and Hiroshi KAWAKAMI
Journal of Japan Institute of Copper, 59(1), pp. 304-308 (2020) (in Japanese).
Ultra-precision cutting has its own problems that are not taken into the consideration in ordinary cutting. Oneof such problems is grain boundary step (GBS) formation. The GBS is a step forming along a grain boundary
on ultra-precision finished surface of polycrystalline metals. The height of GBS can be higher than that of
cutting marks, resulting in reducing the quality of the finished surface. Although grain boundary sliding is
considered as the origin of GBS formation, the growth mechanism of GBSs is still not clear. In the studies ofgrain boundary sliding in creep phenomenon, the apparent activation energy was calculated from thetemperature dependence of creep strain rate, and the mechanism of grain boundary sliding was proposed
based on the calculated activation energy. The apparent activation energy will be effective measure to study
the growth mechanism of GBSs. In this study, in order to calculate the apparent activation energy of GBS
growth process, the change in the height of GBS at -30 ℃, 25 ℃, 60 ℃ and 90 ℃ was measured. The heightof GBS saturated in shorter time at higher temperature. The height increasing with time was higher at higher
temperature. The value of the apparent activation energy was about 20 kJ/mol, which was significantly
smaller than the apparent activation energy of the grain boundary diffusion (104 kJ/mol). Such difference inthe apparent activation energy indicates that the growth of grain boundary steps on ultra-precision finishedsurface originates from mechanisms different from the grain boundary diffusion.
Estimation of R-curve for Mode II Interlaminar Fracture Toughness from Tensile Strength of CFRP
Laminates with Fiber Discontinuities
Hayato NAKATANI, Takaaki WAWABINO and Katsuhiko OSAKA
Proc. of the 1st Russia-Japan Joint Workshop on Composite Materials, Moscow, Russia, Oct.31 - Nov.1, 2
pages (2019).
Tensile tests for unidirectional CFRP laminates that contain three spots of fibre discontinuities dispersed at
an arbitrary interval are carried out. Relations between the interval and the obtained shear strength, which isthe fracture load divided by surface area created by interlaminar crack originated from fibre discontinuities,
has revealed that the fracture of the laminates is dominated by interlaminar fracture toughness of this－19－

material. Energy release rates at crack tips from different spots of fibre discontinuities are qualitatively
evaluated by finite element analysis with virtual crack closure technique. A crack from thicker fibre
discontinuous spot has been found to exhibit higher energy release rate at its tip. The experimentallyobtained fracture stresses are converted into critical energy release rates (CERR) in mode II by applying ananalytical model that calculates changes in strain energy before and after crack growth from the fibre
discontinuity. As a result, relations between the fracture stress and the interval are converted into thatbetween CERR in mode II and crack extension. The trend of CERR plots agrees well with the R-curve
obtained by ENF tests.
Dependence of Vickers Hardness on Layer Thickness in Electrodeposited Ni-Co-Cu/Cu Multilayered
Films
Hiroyuki HAGIWARA, Naofumi KAWAKAMI, Yoshihisa KANEKO and Makoto UCHIDA
Materials Transactions, 60(12), pp.2569-2575, (2019).
The layer thickness dependence of Vickers hardness was investigated in Ni-Co-Cu/Cu multilayered films
having layer thicknesses h ranging from 10 nm to 300 nm. The Ni-Co-Cu/Cu multilayered films were
fabricated by electrodeposition. In the layer thickness range of h ≥ 75 nm, the hardness increased withdecreasing layer thickness. Conversely, the hardness decreased with decreasing layer thickness at h ≤ 75 nm.
At h = 10 nm, the hardness decreased to 97 HV, although the local maximum at h = 75 nm was 210 HV. In
the X-ray diffraction (XRD) profiles around the fcc (111) peak, the 10 nm multilayered film revealed a single
peak, while two peaks corresponding to the Ni-Co-Cu and Cu layers were detected in the other multilayeredfilms. The low hardness of the 10 nm film can be understood from the absence of interface strengthening,which was deduced from the single XRD peak. For 20 nm ≤ h ≤ 75 nm, the two (111) peaks approached eachother. The decreased hardness in this region could be related to sparse misfit dislocations, which can be
estimated from the XRD peak angles.
Fabrication and Enhanced Vickers Hardness of Electrodeposited Co-Cu Alloy Film with HighComposition Gradient
Hiroyuki HAGIWARA, Yoshihisa KANEKO and Makoto UCHIDA
Materials Transactions, 61(4), pp.801-804, (2020).
By applying an oscillating potential wave, we obtained an electrodeposited Co-Cu alloy film in which the Coconcentration changed periodically at a short modulation wave length. A triangular Co concentration
modulation was observed along the film growth direction. The local composition gradient became as high as
50 at%/µm. The Vickers hardness of the composition gradient film was 380 HV. Because this value wasmuch higher than that of simple electrodeposited Co-Cu alloy films, contribution of the composition-gradientstructure to hardness was suggested.
Sliding-Wear Properties of Electro-Deposited Films with Cu and Pulse-Plated Ni Multi-Layers
Hiroyuki HAGIWARA, Kohei NAKAMURA, Yoshihisa KANEKO and Makoto UCHIDA
Materials Transactions, 61(6), pp.1102-1108, (2020).
The purpose of the present study is to investigate the effect of component layer geometry on wear resistancein multilayered structures consisting of soft Cu layers and hard nanocrystalline Ni layers, which were
fabricated by electrodeposition. Pulsed-potentials were applied only during the nickel layer deposition to
obtain the nanocrystalline Ni microstructure. We prepared the multilayers with various component layer
thicknesses and various ratios of the Ni to Cu layer thicknesses. Pulse-plated nickel films without Cu layers
were also prepared for comparison. The formation of nanostructured grains was recognized in thepulse-plated nickel using transmission electron microscopy (TEM). Among the multilayered films preparedin this study, the multilayer with the nanocrystalline nickel layers of 190 nm thickness and the Cu layer of 10
nm thickness revealed the best wear resistance. The weight-loss rate and the worn depth of this multilayered
film were approximately half of those measured in the nanocrystalline nickel film without the Cu layers at
the vertical loads of 10 N and 20 N. These results suggest that the periodic insertion of thin Cu layers canimprove the wear property of nanocrystalline nickel film.
Effect of Heating Condition on Bonding Strength of Hot-Air Welding of Stainless Steel and PA PlatesHiroaki KOBAYASHI, Makoto UCHIDA, Hoichi KITANO and Yosihisa KANEKO
Journal of the Society of Materials Science, Japan, 68(11), pp. 833-838, (2019).
Welding of metal and polymer is attracting example of a joining technique of different materials. However, it
is expected that mechanical behavior of the polymer changes markedly due to heating exceeding the melting－20－

point and residual stress. Plates of polyamide and SUS304 were welded using the hot-air welding machine
under different welding conditions. The influence of heating time, distance and cooling conditions on thebonding strength of the welded structure were evaluated by tensile test. The obtained results demonstrated
that the bonding strength in some specimens became larger than yielding strength of PA depending on thewelding condition. However, the tensile responses considerably varied even for specimens obtained fromsame welding condition. The situation of fracture was classified in three cases, namely, fracture of interface,fracture of polymer, and fracture of welding area. The first and third cases were observed when the total heatgiven to the polymer were large and small, respectively. The strain distribution around the welding area
under small deformation could be a indicator of predicting the fracture pattern of the welded specimen.
Numerical Analyses of Non-Uniform Deformation during Plane Strain Compression of Polycrystalline
Material Using Second-Order Homogenization Method
Masashi SAKAMOTO, Takayuki OTSUKA and Makoto UCHIDA
Journal of the Society of Materials Science, Japan, 68(11), pp. 839-844, (2019).
A second-order homogenization method, in which strain gradient in macroscopic region is considered, hasbeen proposed to evaluate the size effect on the macroscopic deformation. In this study, plane strain
compression of a polycrystalline material is numerically investigated using an FE-based second-orderhomogenization method, and effects of size of macrostructure and friction on macroscopic non-uniform
deformation is discussed. In the simulation of plane strain compression, the friction between an anvil and a
specimen causes non-uniform deformation on the macroscopic region and the size of the specimen affects
the compressive force and the macroscopic distribution of strain when the friction force works. The results
find that under deformation with the strain gradient caused by the friction the compressive force becomeslarger and the macroscopic distribution of strain becomes more inhomogeneous as the size of the specimen
becomes larger. These size effects on the macroscopic region are related to deformation in microstructurethat depends on the strain gradient in the macrostructure.
Effect of Metal Type and Heating Condition on Joint Strength of Metal and Polymer Prepared by Arc
Welding
Hiroaki KOBAYASHI, Makoto UCHIDA, Hoichi KITANO and Yosihisa KANEKO
Quarterly Journal of the Japan Welding Society, 38(2), pp.1s-5s, (2020).
Welding is an important joining technology for dissimilar materials, such as metals and polymers. However,
the joint strength of the welded structure and the mechanical behavior of the polymer change significantly
owing to the thermal history of the polymer during the welding process. In this study, polyamide6 (PA6)
plates were welded to stainless steel (SUS304) and aluminum (A5052) plates using arc welding at different
welding conditions. The effects of the welding conditions and metal type on the joint strength were
investigated using the tensile tests. The experimental results demonstrated that the joint strength of thewelded structure strongly depended on the thermal history of PA6.Whenthe temperature of the metal plateexceeded the melting temperature ofPA6, the joint strength increased. However, the joint strength decreased
considerably when the temperature exceeded the thermal decomposition temperature of PA6. The fracture of
PA6 was classified into two categories depending on the amount of heat applied to PA6, namely, fracture ofinterface and fracture of polymer.

－21－

Physical Electronics and Informatics
Applied Physics and Electronics
Characteristics of Multi-photon Absorption in a β-Ga2O3 Single Crystal
Suguru YAMAOKA, Yusuke MIKUNI, and Masaaki NAKAYAMA
Journal of the Physical Society of Japan Vol.88, 113701 (3 pages) (2019)
We have investigated the characteristics of multi-photon absorption (MPA) in a β-Ga2O3 single crystal at room
temperature using the photoluminescence (PL) of the self-trapped exciton (STE) as a probe. From analysis of theexcitation fluence dependence of the integrated STE-PL intensities at various excitation photon energies, weclearly confirmed the occurrence of two-, three-, four-, and five-photon absorption processes. The optical transition energies in the four- and five-photon absorption processes are almost consistent with the transition energies
between lower-lying valence bands and the conduction-band bottom at the Γ point and those at critical points
away from the Γ point, which are taken from previously reported first-principles calculations, respectively.
DOI: 10.7566/JPSJ.88.113701
Terahertz Electromagnetic Waves Radiated from Coherent Longitudinal Optical (LO) Phonons and
LO-Phonon Plasmon Coupled Modes in (001)-, (110)-, and (111)-oriented Semi-insulating GaAs Single
Crystals
Hideo TAKEUCHI, Takuya NISHIMURA, and Masaaki NAKAYAMA
Semiconductor Science and Technology Vol.35, 065007 (6 pages) (2020)
We report on terahertz electromagnetic waves from coherent longitudinal optical (LO) phonons and coherent
LO-phonon plasmon coupled (LOPC) modes in (001)-, (110)-, and (111)-oriented semi-insulating GaAs single
crystals. The coherent LO phonons and coherent LOPC modes are observed in the three samples. In contrast,
coherent transverse optical (TO) phonons are not observed in the (110)- and (111)-oriented samples in spite ofthat the TO phonon is the Raman active mode. We conclude that only the coherent longitudinal oscillating polarization such as coherent LO phonons and coherent LOPC modes radiate the terahertz wave and that the Raman
selection rule does not contribute to the terahertz-wave-radiation process. The photogenerated electron-density
dependence of the frequencies of the coherent LOPC mode is almost the same in the three samples. This finding
indicates that the coupling of the LO phonon with the plasmon is not influenced by the surface orientations of
the three samples.
DOI: 10.1088/1361-6641/ab7d4aControlling the Dimension of the Quantum Resonance in CdTe Quantum Dot Superlattices Fabricated via
Layer-by-Layer Assembly
TaeGi LEE, Kazushi ENOMOTO, Kazuma OHSHIRO, Daishi INOUE, Tomoka KIKITSU, Hyeon-Deuk KIM,
Yong-Jin PU, and DaeGwi KIM
Nature Commun. Vol. 11, pp. 5471-1-5471-10 (2020)
In quantum dot superlattices, wherein quantum dots are periodically arranged, electronic states between adjacentquantum dots are coupled by quantum resonance, which arises from the short-range electronic coupling of wave
functions, and thus the formation of minibands is expected. Quantum dot superlattices have the potential to be
key materials for new optoelectronic devices, such as highly efficient solar cells and photodetectors. Herein, we
report the fabrication of CdTe quantum dot superlattices via the layer-by-layer assembly of positively charged
polyelectrolytes and negatively charged CdTe quantum dots. We can thus control the dimension of the quantum
resonance by independently changing the distances between quantum dots in the stacking (out-of-plane) andin-plane directions. Furthermore, we experimentally verify the miniband formation by measuring the excitationenergy dependence of the photoluminescence spectra and detection energy dependence of the photoluminescence excitation spectra.
https://doi.org/10.1038/s41467-020-19337-0
Temperature Effects on the Formation and the Relaxation Dynamics of Metal-Organic Interface States
Klaus STALLBERG, Masahiro SHIBUTA, and Ulrich HÖFER
Phys. Rev. B Vol. 102, pp. 121401-1-121401-5 (2020)
Using time-resolved two-photon photoemission, we systematically study temperature effects on the Shockley-derived unoccupied interface states of perylene- and naphthalene-tetracarboxylic dianhydride (PTCDA andNTCDA) adsorbed on Ag(111). With increasing sample temperatures from 100 to 300 K, we observe a continu-－22－ous decrease of the interface-state energy by 0.06 and 0.1 eV, respectively, for the two different molecule/metal
systems. We relate this energy shift to a molecular lifting off the metal surface. The lifting is accompanied withan increase of the interface-state lifetime from 28 to 53 fs for PTCDA and from 60 to 110 fs for NTCDA. This isin qualitative agreement with the reduction of phase space for electron scattering associated with the thermalenergy shift. The magnitude of the experimentally observed lifetime increase, however, is much stronger thanwould be expected from the energy shift alone.
DOI: 10.1103/PhysRevB.102.121401
Spectroscopic Ellipsometry of Monolayered CdS Nanoparticles Assembled by Layer-by-Layer Method
YongGu SHIM, Atsushi KITANO,1 Kazuki WAKITA, and DaeGwi KIM
J. Appl. Phys. Vol. 128, pp. 075303-1-075303-7 (2020)
Semiconductor nanoparticles (NPs) are attractive for use as the constituent blocks of artificial solids. Furthermore, the layer-by-layer (LbL) method allows one to accurately arrange and stack NPs and is being exploredwidely for the fundamental research and development of artificial solids and devices based on NPs. In this study,
we determined the absolute values of the dielectric function of monolayered semiconductor NPs deposited by the
LbL method. The aim was to measure the structural parameters, such as the thickness, NP volume density, andNP number density, of the monolayered films composed of NPs. A novel fully optical method based on spectroscopic ellipsometry was used to evaluate thin films composed of monolayered CdS NPs deposited by the LbL
method. We could successfully determine the absolute values of the dielectric function of the CdS NPs deposited
as monolayered films based on the above-listed parameters with accuracy. Thus, the optical constants of monolayered semiconductor NPs as well as their structural information could be obtained successfully using the proposed method, which is highly suited for nondestructively determining the parameters of thin films, including
those of semiconductor NPs.
doi: 10.1063/5.0007740
Coupled Electronic States in CdTe Quantum Dot Assemblies Fabricatedby Utilizing Chemical Bonding Between Ligands
Yong-Shin LEE, Tatsuya ITO, Kunio SHIMURA, Taichi WATANABE, Hang-Beom BU, Hyeon-Deuk KIM, and
DaeGwi KIM
Nanoscale Vol. 12, pp. 7124–7133 (2020)
Semiconductor quantum dot superlattices (QDSLs) have attracted much attention as key materials for realizing
new optoelectronic devices such as solar cells with high conversion efficiency and thermoelectric elements withhigh electrical conductivity. To improve the charge transport properties in the QDSL-based optoelectronic devices, it is important for the QD structures to form minibands, which are the coupled electronic states between
QDs. A shorter inter-QD distance and a periodic arrangement of QDs are the essential conditions for the formation of minibands. In this study, we use CdTe QDs capped with short ligands of N-acetyl-L-cysteine (NAC) tofabricate a three-dimensional QD assemblies by utilizing the chemical bonding between NACs. The absorption
spectra clearly display the quantum resonance phenomenon originating from the coupling of the wave functions
between the adjacent QDs in the CdTe QD assemblies. Furthermore, we demonstrate the formation of minibands
in the CdTe QD assemblies by examining both, the excitation energy dependence of the photoluminescence (PL)spectra and the detection energy dependence of the PL excitation spectra. The fabrication method of QD assemblies utilizing the chemical bonding between NACs can be applied to all QDs capped with NAC as a ligand.
DOI: 10.1039/d0nr00194e
Photoluminescence ON/OFF Switching of CdSe/ZnS Core/Shell Quantum Dots Coated with Diarylethene
Ligands
Yuya SETO, Rie YAMADA, Daichi KITAGAWA, DaeGwi KIM, and Seiya KOBATAKE
Chem. Lett. Vol. 48, pp. 1394–1397 (2019)
CdSe/ZnS core-shell quantum dots coated with diarylethene ligands were successfully synthesized, and the photoluminescence ON/OFF switching behavior of the quantum dots accompanying the photochromic reactions of
the diarylethene was investigated. The quantum dots exhibited a fast photoluminescence ON/OFF switchingeven in the low photocyclization conversion ratio of the diarylethene.
doi:10.1246/cl.190634－23－

Low-resistance semiconductor/semiconductor junctions with intermediate metal grids for III-V-on-Si
multijunction solar cells
Takashi HISHIDA, Jianbo LIANG, and Naoteru SHIGEKAWA
Japanese Journal of Applied Physics, 59, SBBB04 [5 pages] (2020)
We fabricate semiconductor//metal grid/semiconductor junctions by using surface activated bonding (SAB) of
heavily-doped Si and GaAs substrates to metal grids. The metal grids are self-aligned to SiO2 layers on other Si
substrates. The current–voltage characteristics of these junctions show linear properties. A low junction resistance of 1.99 mΩ/cm2 is achieved for an n+-GaAs//metal grid/n+-Si junction by successively annealing thejunction at 300 °C for 1 h and 400 °C for 1 min in N2 gas ambient. This value is much smaller than an interface
resistance of SABbased GaAs//ITO/Si junctions. These results demonstrate that metal grids could be useful forbonding subcells with low parasitic resistances in fabricating hybrid multijunction solar cells by SAB.
Impact of focused ion beam in the structural analysis of semiconductor interfaces fabricated by surface
activated bonding
Yutaka OHNO (Univ. of Tohoku), Hideto YOSHIDA (Univ. of Osaka), Naoto KAMIUCHI (Univ. of Osaka),
Ryotaro ASO (Univ. of Osaka), Seiji TAKEDA (Univ. of Osaka), Yasuo SHIMIZU (Univ. of Tohoku), Naoki
EBISAWA (Univ. of Tohoku), Yasuyoshi NAGAI (Univ. of Tohoku), Jianbo LIANG, and Naoteru SHIGEKAWA
Japanese Journal of Applied Physics, 59, SBBB05 [5 pages] (2020)
We have shown that the structural and compositional properties of semiconductor interfaces fabricated by surface activated bonding (SAB) would be modified during focused ion beam (FIB) processes operated at room
temperature (RT), especially for wide band-gap materials, and such a modification can be suppressed by FIB
processes operated at lower temperatures. During FIB processes operated at RT, SAB-fabricated Si/Si and
GaAs/GaAs interfaces are amorphized along the interfaces, even at the internal locations deeper than the penetration depth of the FIB, and the impurity distribution across the interfaces is modified. This phenomenon ispresumably due to the atomic diffusion assisted by the point defects that are introduced by FIB irradiation. By
using FIB processes operated at −150 °C, the FIB-induced atomic diffusion would be ignored for Si/Si interfaces.
Meanwhile, the diffusion would be still effective for GaAs/GaAs interfaces, presumably due to the effects ofrecombination-enhanced defect motion under FIB irradiation.
Characterization of Nanoscopic Cu/Diamond Interfaces Prepared by Surface-Activated Bonding: Implications for Thermal Management
Jianbo LIANG, Yutaka OHNO (Univ. of Tohoku), Yuichiro Yamashita (National Metrology Institute of Japan,
National Institute of Advanced Industrial Science and Technology), Yasuo SHIMIZU (Univ. of Tohoku), Naoki
EBISAWA (Univ. of Tohoku), Seongwoo KIM (Adamant Namiki Precision Jewel. Co., Ltd.), Koyama KOJI
(Adamant Namiki Precision Jewel. Co., Ltd.), Yasuyoshi NAGAI (Univ. of Tohoku), Makoto KASU (Univ. ofSAGA), and Naoteru SHIGEKAWA
ACS Applied Nano Materials, 3, 2455-2462 (2020)
The microstructures of Cu/diamond interfaces prepared by surface-activated bonding at room temperature are
examined by cross-sectional scanning transmission electron microscopy (STEM). A crystalline defect layercomposed of Cu and diamond with a thickness of approximately 4.5 nm is formed at the as-bonded interface,which is introduced by irradiation with an Ar beam during the bonding process. No crystalline defect layer isobserved at the 700 °C annealed interface, which is attributed to the recrystallization of the defect layer due tothe high-temperature annealing process. Instead of the defect layer, a mating interface layer and a copper oxide
layer are formed at the interface. The mating interface layer and the copper oxide layer play a role in relieving
the residual stress caused by the difference between the thermal expansion coefficients of diamond and Cu. The
thermal boundary resistance (TBR) of the as-bonded interface is measured to be 1.7 ± 0.2 × 10−8 m2·K/W by thetime domain pulsed-light-heating thermoreflectance technique. These results indicate that the direct bonding of
diamond and Cu is a very effective technique for improving the heat-dissipation performance of power devices.
Effects of post bonding annealing on GaAs//Si bonding interfaces and its application for sacrificial-layer-etching based multijunction solar cells
Naoteru SHIGEKAWA, Ryo KOZONO, Sanji YOON, Tomoya HARA, Jianbo LIANG, and Akira YASUI (Japan
Synchrotron Radiation Research Institute (JASRI/Spring-8))
Solar Energy Materials and Solar Cells, 210, 110501 [7 pages] (2020)
By using the sacrificial layer (SL) etching, GaAs substrates are separated from III–V epi substrate//Si substrate
junctions that are made by surface activated bonding (SAB) technologies. The post-bonding low-temperature－24－

(300-◦C) annealing plays an essential role in achieving a promising (∼90%) bonding yield. The effects of the
post-bonding annealing are investigated by hard X-ray photoemission spectroscopy and current–voltage measurements of GaAs//Si bonding interfaces. It is found that the concentration of oxygen atoms at interfaces is reduced and the resistance decreases to 1.6–2.1 mΩ/cm2 by the low-temperature annealing. Aluminum fluoride
complexes are not observed by X-ray photoelectron spectroscopy on the exposed surfaces of separated GaAs
substrates. The roughness average of the surfaces is ≈0.25–0.30 nm. The characteristics of double junction cells
fabricated on the GaAs//Si junctions prepared by the SL etching are almost the same as those of cells fabricatedby dissolving GaAs substrates after bonding. These results indicate that multijunction cells could be fabricated ina process sequence compatible with reuse of GaAs substrates by combining the SL etching and SAB.
Chemical bonding at room temperature via surface activation to fabricate low-resistance GaAs/Si heterointerfaces
Yutaka OHNO (Univ. of Tohoku), Jianbo LIANG, and Naoteru SHIGEKAWA, Hideto YOSHIDA (Univ. of
Osaka), Seiji TAKEDA (Univ. of Osaka), Reina MIYAGAWA (Nagoya Institute of Technology), Yasuo
SHIMIZU (Univ. of Tohoku), and, Yasuyoshi NAGAI (Univ. of Tohoku)
Applied Surface Science, 525, 146610 [5 pages] (2020)
Bonding mechanism at room temperature (RT) in GaAs/Si heterointerfaces fabricated by surface-activatedbonding (SAB) is examined using cross-sectional scanning transmission electron microscopy combined with low
temperature focused ion beam and time-of-flight secondary ion mass spectrometry. In the bonding process at RT,
atomic intermixing at the interfaces, presumably due to the transient enhanced diffusion assisted by the point
defects introduced in the surface activation process, is confirmed. The defect-assisted atomic diffusion at the interfaces, as well as the formation of atomically clean and activated surfaces, would be the key concept of SAB,
by which we can create tough heterointerfaces at RT. Meanwhile, the defects on the activated surfaces would
degrade the interface resistance. The degraded properties can be recovered by an appropriate annealing after the
SAB processes, although the atomistic structure around the heterointerfaces would be modified during the annealing. By controlling SAB and subsequent annealing conditions, we can obtain low-resistance heterointerfaces
via the optimization of the trade-off relationship between the chemical bonding strength and the electronic properties, determined by the activated surfaces before bonding.
Direct bonding of GaAs and diamond for high power device applications
Jianbo LIANG, Yuji NAKAMURA, Yutaka OHNO (Univ. of Tohoku), Yasuo SHIMIZU (Univ. of Tohoku),
Tianzhuo ZHAN (Waseda Univ.), Takanobu WATABABE (Waseda Univ.), Naoto KAMIUCHI (Osaka Univ.),
Yasuyoshi NAGAI (Univ. of Tohoku), Naoteru SHIGEKAWA
Extended Abstracts of Pacific Rim Meeting on Electrochemical and Solid State Science (PRiME), G01-1634(2020)The direct integrating of GaAs and diamond is achieved at room temperature via a surface activated bonding
method. An ultrathin crystal defect layer composed of GaAs and diamond was formed at the bonding interface.
The thickness of the GaAs and diamond crystal defect layers was determined to be 0.4 and 1.6 nm, respectively.
After annealing at 400 °C, no changes were observed in the thickness of the crystal defect layer and the interfacial structure. The thermal characterization of the transmission line model (TLM) patterns formed on the GaAs
layer bonded to diamond and sapphire substrates is demonstrated. The thermal resistance of the GaAs TLM patterns formed on the diamond and sapphire substrates was determined to be 6 and 34.9 K/W, respectively. The
GaAs TLM patterns formed on the diamond showed an excellent heat dissipation property due to the high thermal conductivity of diamond.
Fabrication of Diamond/Cu Direct Bonding for Power Device Applications
Shinji KANDA, Yasuo SHIMIZU (Institute of Materials Research (IMR), Tohoku Univ.), Yutaka OHNO (Institute of Materials Research (IMR), Tohoku Univ.), Kenji SHIRASAKI ((Institute of Materials Research (IMR),
Tohoku Univ.), Yasuyoshi NAGAI (Institute of Materials Research (IMR), Tohoku Univ.), Makoto KASU (Univ.
of SAGA), Naoteru SHIGEKAWA, and Jianbo LIANG
Japanese Journal of Applied Physics, 59, SBBB03 [5 pages] (2020)
Direct bonding of diamond and Cu was successfully fabricated by surface activated bonding (SAB) method atroom temperature. The interfacial structures of the diamond/Cu bonding interface before and after annealing at
500 and 700 ℃ were investigated by transmission electron microscope (TEM) and electron energy-loss spectroscopy (EELS). A 4-nm-thick transition layer was formed at the bonding interface, the transition layer thickness decreased with annealing temperature. It was found that the atomic ratio of sp2 bonding in the bonding in-－25－

terface was larger than that of the diamond separated from the bonding interface by approximately 50 nm, whichindicated that the transition layer was composed of the amorphous or graphite and diamond. After annealing at
700 ℃, an intermediate layer of about 2 nm thick was observed at the bonding interface. There were no nanovoids and micro-cracks observed at the interface with annealing at a temperature as high as 700 ℃. These results
indicated that the diamond/Cu bonding interface has high thermal stability and can withstand the temperaturerise of power devices during operating.
III-V Thin-Film Solar Cells Bonded to Si substrates via Metal Grids
Takashi HISHIDA, Jianbo LIANG, and Naoteru SHIGEKAWA
Extended Abstracts of 2019 Extended Abstracts of Pacific Rim Meeting on Electrochemical and Solid State Science (PRiME), G01-1635 (2020)
Ⅲ-Ⅴ on Si multijunction (MJ) solar cells are promising as next-generation solar cells since they can provide
high efficiency with low cost in comparison with conventional Si and Ⅲ-Ⅴ MJ cells. In fabricating such III-V/Si
MJ cells, Ⅲ-Ⅴ subcells are placed on Si bottom cell by hybrid approaches such as surface-activated bonding(SAB). The bonding interfaces with lower interface resistances are strongly required so as to achieve better performance of hybrid MJ cells. It was found that the resistance across the directly-bonded III-V/Si interfaces in MJ
cells was higher than the resistance in junctions made of heavily-doped substrates because of the thin heavily-doped bonding layers in actual subcell structures. It was reported that indium tin oxide (ITO) films as intermediate layers between III-V and Si subcells played a role of lowering the series resistance of MJs [1]. It was
found, however, that the resistance of GaAs//ITO/Si junctions increased by annealing them [2]. Furthermore, thequantum efficiency of Si bottom cells was lowered by inserting the ITO layers because of the free carrier absorption of ITO layers.
Nanostructural Investigation on GaAs//Indium Tin Oxide/Si Junctions for III-V-on-Si Hybrid Multijunction Cells
Tomoya HARA, Jianbo LIANG, Kenji ARAKI (Toyota Technological Institute), Takefumi KAMIOKA (Toyota
Technological Institute), Hassanet SODABANLU (The Univ. of Tokyo), Kentaroh WATABABE (The Univ. ofTokyo), Masakazu SUGIYAMA (The Univ. of Tokyo), and, Naoteru SHIGEKAWA
Extended Abstracts of Pacific Rim Meeting on Electrochemical and Solid State Science (PRiME), G01-1636(2020)
Hard X-ray photoemission spectroscopy (HAXPES) measurements and transmission electron microscopy (TEM)
observations are performed on GaAs thin film//Indium tin oxide (ITO)/Si junctions fabricated by surface-activated bonding and selective wet etching. Both of the Ga-O/Ga-As ratio in the Ga 2p3/2 HAPES core
spectrum (Fig. 1(a)) and As-O/As-Ga ratio in the As 2p3/2 HAXPES core spectrum (Fig. 1(b)) demonstrate that
the GaAs layers are oxidized after annealing at 400 °C. This observation is consistent with the formations of a
~1-nm-thick intermediate layer in the cross-sectional TEM image of the junctions after the 400 °C annealing, as
is shown in Figs. 2(a) and 2(b). It is found by using in-house X-ray photoelectron spectroscopy in combination
with Ar+ bombardment that the oxide layers are formed at GaAs//ITO bonding interfaces after annealing at
200 °C or higher temperatures. The observation of the oxide layers corresponds with the onset of resistivity increase in GaAs//ITO/Si junctions due to the annealing [1]. These results suggest that annealing brings about thereaction between GaAs and ITO layers and hence the oxidation of GaAs layers, which causes the degradation of
the electrical properties of GaAs//ITO/Si junctions. A fabrication process at lower temperatures is likely to berequired so as to fully exploit the advantage of ITO as intermediate layers in III-V//Si hybrid tandem solar cellswith lower series resistance.
Microscopic Picture of Direct Bonding Via Surface Activation for Low-resistance Si/Wide-Gap Semiconductor Heterointerface
Yutaka OHNO (Institute of Materials Research (IMR), Tohoku Univ.), Jianbo LIANG, Naoteru SHIGEKAWA,
Hideto YOSHIDA (Univ. of Osaka), Reina MIYAGAWA (Nagoya Institute of Technology), Yasuo SHIMIZU(Institute of Materials Research (IMR), Tohoku Univ.), and, Yasuyoshi NAGAI Institute of Materials Research(IMR), Tohoku Univ.)
Extended Abstracts of Pacific Rim Meeting on Electrochemical and Solid State Science (PRiME), G01-1648(2020)
Surface-activated bonding (SAB) [1], that is a direct wafer bonding process without additional buffer layers, is apromising method to fabricate tough and steep heterointerfaces at low cost. SAB can fabricate any heterointerfaces free from dislocations and cracks, even for dissimilar materials with different crystal structures and lattice－26－

constants, without high-temperature annealing. Recently, SAB is applied to the next-generation semiconductors
such as diamond, SiC, and GaN, as well as to the basic semiconductors such as Si and GaAs, towards
low-resistance semiconductor-to-semiconductor heterointerfaces free from adherent layers. Even though suchbonding is successfully demonstrated, the principle of the SAB is still controversial due to the difficulty of analyzing their non-equilibrium heterostructures at an atomistic level.
Mechanism of direct bonding via surface activation to fabricate Si/GaAs heterointerfaces towards tandem
solar cells
Yutaka OHNO (Institute of Materials Research (IMR), Tohoku Univ.), Jianbo LIANG, Naoteru SHIGEKAWA,
Hideto YOSHIDA (Univ. of Osaka), Seiji TAKEDA (Univ. of Osaka), Reina MIYAGAWA (Nagoya Instituteof Technology), Yasuo SHIMIZU (Institute of Materials Research (IMR), Tohoku Univ.), and, Yasuyoshi NAGAI Institute of Materials Research (IMR), Tohoku Univ.)
Extended Abstracts of 2020 European Materials Research Society (E-MRS) Spring Meeting, Congress & Exhibition Centre, Strasbourg, France, May 25-29, 2020
We have examined the bonding mechanism in Si/GaAs heterointerfaces towards tandem solar cells fabricated bysurface-activated bonding (SAB) at room temperature (RT), by scanning transmission electron microscopy combined with focused ion beam operated at low-temperatures [1]. In the SAB process, wafer surfaces are activatedby the irradiation of inert atoms in a high vacuum, and the surfaces are then bonded by the contact. In the bonding process at RT, atomic intermixing across the interfaces, due to the transient enhanced diffusion assisted by
the point defects introduced in the surface activation process, forms a nanolayer having gradient composition.
Spontaneous formation of the gradient nanolayer, acting as a buffer layer that can reduce the interface energy, as
well as forming strong chemical bonds, would be the key concept of SAB, by which we can create tough andsteep heterointerfaces of dissimilar materials at low cost. On the other hand, those point defects can degrade theelectric properties such as interface resistances. The decrease of the defects would play a crucial role in fabricating electronic devices with SAB techniques. By controlling SAB conditions, we can obtain low-resistance
Si/GaAs heterointerfaces via the optimization of the trade-off relationship between the chemical bonding
strength and the electric properties, determined by the distribution of point defects beneath the activated surfaces.
Mechanism of surface activated bonding for low-resistance Si/diamond and Si/GaAs heterointerfaces
Yutaka OHNO (Institute of Materials Research (IMR), Tohoku Univ.), Jianbo LIANG, Naoteru SHIGEKAWA,
Hideto YOSHIDA (Univ. of Osaka), Reina MIYAGAWA (Nagoya Institute of Technology), Yasuo SHIMIZU(Institute of Materials Research (IMR), Tohoku Univ.), and, Yasuyoshi NAGAI Institute of Materials Research(IMR), Tohoku Univ.)
Extended Abstracts of The 15th International Conference Beam Injection Assessment of Microstructures in Semiconductors, Saint Petersburg, Russia, July 19-24, 2020
We have examined the bonding mechanism in Si/GaAs and Si/diamond heterointerfaces fabricated by surface-activated bonding (SAB) at room temperature (RT), using high-angle annular dark-field (HAADF) and energy dispersive x-ray spectroscopy (EDX) under scanning transmission electron microscopy (STEM) combinedwith time-of-flight secondary ion mass spectrometry (TOFSIMS). In the SAB process, wafer surfaces are activated at RT by the irradiation of inert atoms in a high vacuum, and the surfaces are then bonded by the contact
under a pressure. In the bonding process at RT, atomic intermixing across the interfaces, due to the transient enhanced diffusion assisted by the point defects introduced in the surface activation process, forms an intermediate
layer of 4-5 nm thick having gradient composition (see Fig. 1 for Si/GaAs interface). Interestingly, no structuraldefect, such as cracks and dislocations, is introduced at the heterointerfaces even after high-temperature annealing, presumably due to the gradient nanolayer acting as a buffer layer that can reduce the interface energy, as
well as forming strong chemical bonds. Spontaneous formation of the gradient nanolayer is, therefore, the key
concept of SAB, by which we can create tough and steep heterointerfaces of dissimilar materials at low cost. On
the other hand, since the point defects can degrade the electronic properties such as interface resistances, the decrease of the defects would play a crucial role in fabricating electronic devices with SAB techniques. The degraded properties can be recovered by an appropriate annealing after the SAB processes, although the atomistic
structure around the heterointerfaces would be modified during the annealing. By controlling SAB and subsequent annealing conditions, we can obtain low-resistance hetero-interfaces via the optimization of the trade-off
relationship between the chemical bonding strength and the electronic properties, determined by the distributionof point defects beneath the activated surfaces before bonding.

－27－

Acoustic Signal Production in Ethanol by Energetic Xenon Ions
Masanori KOBAYASHI(Chiba Institute of Technology), Takashi MIYACHI(Chiba Institute of Technology),
Osamu OKUDAIRA(Chiba Institute of Technology), Seiji TAKECHI, Atsuma KUROZUMI, Takefumi UNO,
Maki NAKAMURA(Nagoya University), Hiromi SHIBATA(Osaka University), Nagaya OKADA(Honda Electronics Co., Ltd.), Masayuki FUJII(Famscience Co., Ltd.), Takeshi MURAKAMI(National Institutes for Quantum and Radiological Science and Technology) and Yukio UCHIHORI(National Institutes for Quantum and Radiological Science and Technology)
Jpn. J. Appl. Phys., Vol. 59, pp. 028004-1-028004-3 (2020)
Acoustic signals produced by irradiating ethanol with 400 MeV/n Xe ions were experimentally studied. The
signals were detected by an array of piezoelectric PZT elements. They were categorized into two types: one wasa primary product of the incident fast ions; the other was a secondary product resulting from an energy release toethanol just before the ions stopped and subsequently diffused in ethanol. A possible mechanism of the secondary signal is discussed in association with the Bragg peak formation.
On Cold Atmospheric-pressure Plasma Jet Induced DNA Damage in Cells
Nishtha GAUR (University of Lancaster), Hirofumi KURITA (Toyohashi University of Technology), Jun-Seok
OH, Saki MIYACHIKA (Toyohashi University of Technology), Masafumi ITO (Meijo University), Akira MIZUNO (Toyohashi University of Technology), Allison COWIN (University of South Australia), Sarah ALLINSON (University of Lancaster), Robert D. SHORT (University of Lancaster) and Endre J. SZILI (University ofSouth Australia)
J. Phys. D: Appl. Phys. Vol. 54, 034203 (11 pages) (2021)
To investigate the potential role of the hydroxyl radical (•OH) in cold atmospheric plasma (CAP) jet treatment,
two fluorescence-based methodologies are utilised to measure DNA strand breaks. The first comprises a model
system of a double-stranded DNA oligomer, where the respective strand ends are tagged with fluorophore andquencher molecules; and the second, a cell culture system reporting DNA strand breaks using the γ-H2AX assay.
During the various CAP jet treatments, optical emission spectroscopy is used to detect the •OH in the gas phaseand electron spin resonance is used to detect the •OH in solution. The CAP jet production of the •OH is shown tocorrelate to CAP jet induced DNA damage both with the DNA model and in biological cells. Results indicatethat the CAP jet induces a higher degree of DNA damage when the CAP plume is in contact with the target solution. The potential of a ‘plasma screen’ based upon a hydrogel film, as a method to remove the DNA-damaging•OH species from reaching skin cells, is shown to significantly reduce DNA damage whilst facilitating the delivery of hydrogen peroxide. These findings could aid in the development of CAP jet-based applications where
DNA damage is the objective (e.g. in cancer treatment) and others where it is to be avoided, e.g. in open-woundtreatment and dermatology.
DOI: https://doi.org/10.1088/1361-6463/abb8ab
Atomic Oxygen Radical-induced Intracellular Oxidization of Mould Spore Cells
Yuta TANAKA (Meijo University), Jun-Seok OH, Hiroshi HASHIZUME (Nagoya University), Takayuki OHTA
(Meijo University), Masashi KATO (Meijo University), Masaru HORI (Nagoya University), and Masafumi ITO(Meijo University)
Plasma Process Polym. Vol. 17, e2000001 (8 pages) (2020)
The inactivation mechanism of mould spores using plasma-generated neutral reactive oxygen species (ROS) wasinvestigated in this paper. Typical cell viability using a counting of colony forming unit assay indicated a majorstate of the spore cells. Both intracellular and extracellular damages have been investigated by a couple ofwell-established cell visualization techniques: confocal fluorescence emission microscopy, scanning electron
microscopy, and transmission electron microscopy. It is revealed in this paper that the combination of the spore
cell viability with those visualization results strongly suggested an early stage of the cell inactivation when ROS
can induce intracellular lipid peroxidation through both nanometer-thick lipid cell membrane and less damaged
several hundred nanometer-thick cell wall.
DOI: https://doi.org/10.1002/ppap.202000001
Oxidation Processes of NO for Production of Reactive Nitrogen Species in Plasma Activated Water
Kunihide TACHIBANA (Kyoto University), Jun-Seok OH and Toshihiro NAKAMURA (Kyoto University)
J. Phys. D: Appl. Phys. Vol. 53, 385202 (14 pages) (2020)
To understand the mechanisms for selective productions of NO2− and NO3− as reactive nitrogen species (RNS) in
plasma activated water, we studied the oxidation reactions of NO as the primary species supposing O, O2, O3,－28－

OH, and H2O2 as possible oxidants. A coaxial-type dielectric barrier discharge reactor was employed in cascade
connection to a reservoir and/or a water bubbler. First, the densities of NO and NO2 in the gas phase were measured with gas sensors in two gas systems: N2 admixed with water vapor and N2 admixed with O2, for comparison.
It was found that while the density of NO in the latter case was one third of that in the former case owing to thedifference in the first-step oxidation to NO2 or HNO2, the total yields of RNS in both cases were comparable. To
investigate the oxidation pathways, admixing NO and NO2 in the downflow of the reactor was attempted to estimate their reactions with those oxidants and accommodation behaviours on the water surface. Injecting the effluent gas from discharge plasma into solutions of O2, O3, and H2O2, and injecting O3 into PAW, vice versa, wereattempted to inspect the reactions in the liquid phase or at the gas–water interface. Based on the obtained results,
it was found that, in the N2-H2O gas system, OH functions as the oxidant of NO to HNO2, exclusively yielding
NO2− in solution with no effective second-step oxidation to NO3 or HNO3. On the other hand, in the N2-O2 gas
system, O3 functions as the major oxidant in the successive oxidation from NO to NO2 to NO3, producing NO3−
predominant PAW; however, the second-step oxidation in the gas phase is competing with the oxidation reactions in the liquid phase.
DOI: https://doi.org/10.1088/1361-6463/ab91eb
Microplasma Discharge in Deionized Water and Artificial Seawater
Akimitsu HATTA (Kochi University of Technology), Vladislav GAMALEEV (Nagoya University), Jun-Seok
OH and Hiroshi FURUTA (Kochi University of Technology)
Intl. J. Plasma Environ. Sci. Technol. Vol. 13, 1 (6 pages) (2019)
Microplasma discharges in deionized water and artificial seawater were investigated using pin-to-plate electrodes with a gap of a several tens of microns. By using a pulse voltage source, microdischarge was operated indeionized water and diluted artificial seawater and compared with discharge in ambient air. To operate the microdischarge in undiluted artificial seawater, a pulse current source (impulse generator) was used to supply thebreakdown voltage with sufficient current. Even in seawater with an electrical conductivity of 45 mS/cm, microplasma discharges were reproducibly ignited at applied voltages below 1 kV. In the optical emission spectrum forthe microplasma in artificial seawater, the main components of Na, Mg, Ca, K, S, H, and O were observed as
distinguishable isolated lines, including lines for Pd, Ag and Fe from the electrodes.
DOI: https://doi.org/10.34343/ijpest.2019.13.01.001
The Measurement of Yeast Status by analyzing the electrical response waveform -using the phase angles ofharmonicsKeita TAMURA, Naoto HIGASHIHARA, Daichi TANAKA, Masafumi MURAJI, Kenji TANAKA, Tatsuru
SHIRAFUJI
Record of the 2019 Kansai-section Joint Convention of Institutes of Electrical Engineering, Japan, G2-10, p.51
(2019) (in Japanese)－29－Electrical and Information Engineering
Further Crosstalk Reduction Method with Eye-Tracking for Glasses-Free Stereoscopic Display inBoth Portrait and Landscape Modes
Yukiya YAMAGUCHI, Hiiro NAKAMURA, Goro HAMAGISHI, Kayo YOSHIMOTO, Takuya
MATSUMOTO (Kyocera Corp.), Kaoru KUSAFUKA (Kyocera Corp.), Hideya TAKAHASHI
Proc. The International Display Workshops, Sapporo, Nov. 29, Vol.26, pp.982-985 (2019).
We previously proposed the glasses-free stereoscopic display using the slanted parallax barrier with the eyetracking system. The previously proposed system had very high image quality. If we adopted the LC panel as
the active parallax barrier, it was possible to switch into two different patterns of barriers correspond to theportrait and the landscape modes. Each barrier pattern corresponding to the two modes had the same barrier
pitch and slanted angle, so basically the same eye-tracking algorithm could be applied in sensing the viewing
position. Moreover, by dividing the screen into multiple areas and controlling the image positions in eacharea according to the viewing position, it was possible to keep the stereoscopic vision even if the viewer
moved in the depth direction toward the screen. However, as the moving distance from the optimum viewing
distance increased, the number of subpixels observed simultaneously with both eyes increased. We call these
subpixels “crosstalk subpixels.” As the number of the crosstalk subpixels increases, the effect of stereoscopic
vision is reduced. Therefore, the expansion of the viewing area in the depth direction was limited. Therefore,
in this paper, we propose a method to reduce the crosstalk by displaying black images on the crosstalk
subpixels. By this method, the crosstalk ratio can be stably suppressed low even if the viewer moves far fromthe OVD in the depth direction, so the viewing area can be expanded compared to the previous proposedsystem. To verify the effectiveness of the proposed system, we evaluated the crosstalk ratio at each viewing
distance for both portrait and landscape modes in the prototype system.
Development of vessel position estimation system based on pixelwise refocusing using light fieldimaging
Kayo YOSHIMOTO, Hideya TAKAHASHI, Kohei YAMAMOTO, Kenji YAMADA (Osaka University)
Proc. SPIE Advanced Biomedical and Clinical Diagnostic and Surgical Guidance Systems XVIII, San
Francisco, Feb. 21, Vol.11229, 112291N CD-ROM (2020).
Venipuncture is a medical practice which is ordinarily performed in hospital. However, it is a difficult
procedure as the occurrence of many failure of the puncture and sometimes medical accidents such as nerve
damage and blood vessel damage are reported. This is caused by the difficulty of visually identification of
the blood vessel. Although the depth information of the blood vessel is also important, the existing system inclinical practice can visualize vessels only by two dimensional images. In our previous work, we proposed amethod that adds angle filtering to a refocus-based system using light field imaging to estimate the threedimensional position of blood vessels. Angular filtering can reduce blurring of blood vessel image obtainedusing infrared light due to the strong scattering properties of biological tissue. By applying the refocusing
technique to an image with reduced blur, it is possible to obtain enhanced cross-sectional information of ablood vessel using near-infrared light at each depth. However, in the previous study, only phantom model
results were reported, and it was not possible to study practicality. In this paper, we report the results ofapplying and verifying the effectiveness of the proposed method to human hand.
Control method of active parallax barrier and binocular image for glasses-free stereoscopic display
according to viewing position Analysis of displayable depth range for retinal projection type super
multi-view 3D head-mounted display using the time division projection optical system
Hiiro NAKAMURA, Tomoya KITADA, Goro HAMAGISHI, Kayo YOSHIMOTO, Kaoru KUSAFUKA(Kyocera Corp.), Hideya TAKAHASHI
Proc. SPIE Advanced in Display Technologies X, San Francisco, Feb. 26, Vol.11304, 1130414 CD-ROM(2020).
In 3D displays based on parallax barriers, active parallax barriers that can change the barrier patternaccording to the viewing position have been proposed to expand the viewing area. However, the production
cost increases because the active barrier requires a special LC panel. Therefore, to lower the cost, we propose
a glasses-free stereoscopic display using an active parallax barrier of an LC panel with the same
specifications as the image LC panel. The ideal image pattern cannot be formed because the minimum
control unit of the LC panel is equal to one subpixel. However, by using an image cycle pitch method(ICPM) that periodically increases the horizontal pitch of one pair of binocular images by one subpixel, we
can realize the ideal relationship between the average pitch of the binocular image and the barrier pitch. In－30－our previous research, we could make the average pitch match to the ideal pitch on the discrete optimum
viewing distances (OVDs), but we could not follow the viewing position between the discrete OVDs. In thispaper, we propose the ICPM that can keep the stereoscopic vision even at any viewing position. In order toverify the effectiveness of the proposed method, we made the prototype displays and evaluated them. As aresult, we showed the crosstalk ratio could be suppressed low over a very wide range by using the proposed
method. Also, we confirmed we could obtain the stereoscopic vision at the viewing distance from 300 mm to
729 mm by a subjective evaluation.
Retinal image generation method for retinal projection type super multi-view 3D head-mounted
display
Junya KOHNO, Kayo YOSHIMOTO, Hideya TAKAHASHI
Proc. SPIE Advanced in Display Technologies X, San Francisco, Feb. 26, Vol.11304, 1130413, CD-ROM(2020).
We have proposed the retinal projection type super multi-view head mounted display (HMD). The super
multi-view method provides stereoscopic information by inducing the accommodation of the human eye byblurring the retinal image. This method uses the principle of Maxwellian view and reconstruct the blur image
by overlapping projected each parallax image on the retina. However, considering only the degree of theoverlap of the projected parallax images on the retina is not enough for reconstructing the real blur. In orderto overcome this problem, we propose the optimal method considering not only the degree of the overlap of
the parallax images projected on the retina but also the light intensity of each parallax image to reconstruct
the real blur. From the evaluation experiment, we verified that the proposed method improves the
reproducibility of blur compared to the method considering only the degree of superimposition of theparallax images projected on the retina. Furthermore, it was also confirmed that the prototype system candisplay 3D images in the depth range of human ocular accommodation from 200mm to 2000mm. The super
multi-view HMD based on the proposed method can induce the accommodation of the human eye with thehigh reproducibility blur and provide more natural 3D images.
Expanding Tree-Based Classifiers Using Meta-Algorithm Approach: An Application for Identifying
Students' Cognitive Level
Yuni YAMASARI (ITS), Supeno Mardi Susiki NUGROHO (ITS), Kayo YOSHIMOTO, Hideya
TAKAHASHI, Mauridhi Hery PURNOMO (ITS)International Journal of Innovative Computing, Information and Control, Vol.15, No.6, pp.2085-2107(2019).
Accurate identification of student cognitive levels is a crucial problem for a teacher in deciding theappropriate method for a teaching and learning process. Nevertheless, not much research focuses on this area.
Therefore, in this paper, we investigate the problem of how to improve the classification performance todiscover the more suitable students’ cognitive level. We expand tree-based classifiers using a meta-algorithm
called “LogitBoost” in the mining process. Then, to support this meta-algorithm to work optimally, we
introduce the multivariate normality test and the combination of the discretization method and k-NN on the
pre-processing stage. These designed schemes are intended to find the student data normality and to specify
the number of the students’ cognitive levels. Also, we propose a feature selection approach: correlation- andreliefbased feature selection to eliminate unnecessary features. The experimental results show that our
proposed method can enhance the classification performance in the identification process significantly.
Identifying Dominant Characteristics of Students’ Cognitive Domain on Clustering-based
Classification
Yuni YAMASARI (ITS), Supeno Mardi Susiki NUGROHO (ITS), Kayo YOSHIMOTO, Hideya
TAKAHASHI, Mauridhi Hery PURNOMO (ITS)International Journal of Intelligent Engineering & Systems, Vol.13, No.1, pp.167-180 (2020).
The rapid growth of information and communications technology-based educational tools generates a large
volume of student data with many features (characteristics). However, the mining process in the clusteringtask of student data is not often done optimally, so the performance of the system decreases. To overcome
this problem, we propose a discretization method on logistic regression to determine the most optimal
number of clusters. Additionally, we introduce a technique that combines the features selection using a filterand wrapper-based procedures (HFS) to identify the dominant features of the students' cognitive domains.
Furthermore, we evaluate the identification result by three clustering methods, namely: K-means, EM, and－31－

Farthest first. Finally, we propose the clustering-based classification so the results can be measured by using
the classification metrics. Here, we apply two evaluation techniques, namely: cross-validation andpercentage split. The experimental results indicate that our approach describes predominance, in terms ofclassification metrics over conventional methods. Our approach is around 10,847-11,134 percent higher interms of accuracy average than the original features on both the assessment techniques. Also, this approachsignificantly reduces the time taken to create a prototype between 0.0167-0.027 seconds. This gives theimpact on a significant reduction in the model created to the number of unsuitable students on classes basedon the cognitive domain, namely: 3-12 students.
Spin-Pump-Induced Spin Transport in a Thermally-Evaporated Pigment-Red Film
Kazuhiro NISHIDA, Yoshio TEKI (Graduate School of Science, OCU), Eiji SHIKOH
Solid State Communications, Vol.312, pp.113898-1 ~ 113898-5 (2020).
We report the spin transport properties in a pigment-red (perylene-3,4,9,10-tetracarboxylic dianhydride:
PTCDA) film prepared by thermal evaporation. In a palladium(Pd)/PTCDA/Ni80Fe20 tri-layer sample, a purespin-current is generated in the PTCDA layer by using the spin-pumping driven by the ferromagnetic
resonance of the Ni80Fe20 film. The generated spin current is absorbed into the Pd layer, converted into acharge current with the inverse spin-Hall effect in Pd, and detected as an electromotive force. This is clear
evidence for the spin transport in a PTCDA film, and it is confirmed that a PTCDA film is useful not only asa robust protection layer material but also as a spintronic material.

－32－

Applied Chemistry and Bioengineering
Creation and Stabilisation of Tuneable Open Metal Sites in Thiocyanato-Bridged Heterometallic
Coordination Polymers to Be Used as Heterogeneous Catalysts
Hiroyasu TABE, Masaaki MATSUSHIMA, Rika TANAKA, Yusuke YAMADA
Dalton Trans., Vol. 48, pp. 17063-17069 (2019)
A series of thiocyanato-bridged heterometallic coordination polymers with 3D reticular network havebeen synthesised by the reaction of [PtIV(SCN)6]2– with MII ions to form {MII[PtIV(SCN)6]}n and{[MII(CH3OH)2][PtIV(SCN)6]}n (MII = MnII, FeII, CoII, NiII or CuII) in water and methanol, respectively.
Single-crystal X-ray analyses manifested the absence of open metal sites in {MII[PtIV(SCN)6]}ns andformation of potential open metal sites at MII ions of {[MII(CH3OH)2][PtIV(SCN)6]}ns by coordination of
methanol. One of the two coordinating methanol molecules in {[CoII(CH3OH)2][PtIV(SCN)6]}n was
replaced by pyridine to stabilise the open metal sites, because the methanol molecules are too labile tomaintain open metal sites in water. Heterogeneous catalysis of coordination polymers with and without
open metal sites was examined for organophosphate hydrolysis and photocatalytic water oxidation toclarify requisites to be used as heterogeneous catalysts.
Unique Half Embedded/Exposed PdFeCu/C Interfacial Nanoalloy as High‐PerformanceElectrocatalyst for Oxygen Reduction Reaction
Biraj Jyoti BORAH, Himadri SAIKIA, Chiranjita GOSWAMI, Kumar Kashyap HAZARIKA, Yusuke
YAMADA, Pankaj BHARALI
ChemCatChem, Vol. 11, pp. 3522-3529 (2019)
Design of high‐performance non‐Pt electrocatalyst for fuel cell applications is greatly anticipated. Herein,
we have developed a unique half‐embedded and half‐exposed interfacial PdFeCu nanoalloy anchoredonto carbon matrix. The stable electronic coupling between the carbon matrix and PdFeCu nanoalloy
possess very fast interfacial electron transfer which in turn enhances the electron conductivity. This makes
the trimetallic nanoalloy high performing oxygen reduction reaction (ORR) electrocatalyst in both basic
and acidic media. The PdFeCu/C nanoalloy exhibits enhanced electrochemically active surface area thanvarious PdFe/C bimetallics as well as benchmark 20 wt% Pt/C and Pd/C. As a result, it offers larger active
sites for ORR and eased the electron transport during the electrocatalysis. It exhibits 1.5‐ and 2.4‐foldhigher mass activity in comparison to the Pt/C and Pd/C. Furthermore, it exhibits long‐term stability andlow onset potential compared to those of the other catalysts. Thus, the present investigation shows
potential strategy for the design and synthesis of Pt‐free electrocatalyst with remarkable catalytic activity
and stability.
Utilization of Core-Shell Nanoparticles to Evaluate Subsurface Contribution to Water Oxidation
Catalysis of [CoII(H2O)2]1.5[CoIII(CN)6] Nanoparticles
Hiroyasu TABE, Akira KITASE, Yusuke YAMADA
Appl. Catal. B, Vol. 262, Article No. 118101 (8 pages) (2020)
Nanoparticles of a cyano-bridged polynuclear metal complex, [CoII(H2O)2]1.5[CoIII(CN)6], have beenreported as highly efficient heterogeneous catalysts for photocatalytic water oxidation, however, reasonsfor the high catalytic activity have yet to be clarified. Herein, the water oxidation catalysis wasinvestigated for a series of core-shell nanoparticles composed of cyano-bridged polynuclear metal
complexes employing [CoII(H2O)2]1.5[CoIII(CN)6] as the shell to assess subsurface contribution. The
catalytic activity of the core-shell nanoparticles closely related to that of the core parts suggests that thesubsurface contributes to the nanoparticle catalysis. Then, catalysis of the core-shell nanoparticles
employing [CuII(H2O)2]1.5[FeIII(CN)6] as the catalytically inactive core but isostructural to[CoII(H2O)2]1.5[CoIII(CN)6] was examined to determine the thickness directly involved in the catalytic
reaction. The catalytic activity depending on the thickness of the [CoII(H2O)2]1.5[CoIII(CN)6] shell suggests
the involvement of CoII ions at the subsurface up to 7 nm. These results suggest that the microporous
structure of [CoII(H2O)2]1.5[CoIII(CN)6] enlarged by intrinsic defects is a reason for the high catalytic
activity, where the photosensitizer and water molecules utilize the subsurface CoII ions as active sites.
Immobilization of Ir(OH)3 Nanoparticles in Mesospaces of Al-SiO2 Nanoparticles Assembly toEnhance Stability for Photocatalytic Water Oxidation
Gentaro SAKAMOTO, Hiroyasu TABE, Yusuke YAMADA－33－

Catalysts, Vol. 10, Article No. 1015 (14 pages) (2020)
Iridium hydroxide (Ir(OH)3) nanoparticles exhibiting high catalytic activity for water oxidation were
immobilized inside mesospaces of a silica-nanoparticles assembly (SiO2NPA) to suppress catalytic
deactivation due to agglomeration. The Ir(OH)3 nanoparticles immobilized in SiO2NPA(Ir(OH)3/SiO2NPA) catalyzed water oxidation by visible light irradiation of a solution containing
persulfate ion (S2O82–) and tris(2,2’-bipyridine)ruthenium(II) ion ([RuII(bpy)3]2+) as a sacrificial electron
acceptor and a photosensitizer, respectively. The yield of oxygen (O2) based on the used amount of S2O82–
was maintained over 80% for four repetitive runs using Ir(OH)3/SiO2NPA prepared by the coaccumulation method, although the yield decreased for the reaction system using Ir(OH)3/SiO2NPA
prepared by the equilibrium adsorption method or Ir(OH)3 nanoparticles without SiO2NPA support under
the same reaction conditions. Immobilization of Ir(OH)3 nanoparticles in Al3+-doped SiO2NPA (AlSiO2NPA) results in further enhancement of the catalytic stability with the yield of more than 95% at the
fourth run of the repetitive experiments.
Single‐Crystal‐to‐Single‐Crystal Installation of Ln4(OH)4 Cubanes in an Anionic
Metallosupramolecular Framework
Nobuto YOSHINARI, Natthaya MEUNDAENG, Hiroyasu TABE, Yusuke YAMADA, Satoshi
YAMASHITA, Yasuhiro NAKAZAWA, Takumi KONNO
Angew. Chem. Int. Ed., Vol. 59, pp. 18048-18053 (2020)
Post-synthetic installation of lanthanide cubanes into a metallosupramolecular framework via a single‐
crystal‐to‐single‐crystal transformation is presented. Soaking single crystals of K6[Rh4Zn4O(L‐cys)12] (L‐H2cys = L‐cysteine) in a water/ethanol solution containing Ln(OAc)3 (Ln3+ = lanthanide ion) results inthe exchange of K+ by Ln3+ with retention of the single crystallinity, producing Ln2[Rh4Zn4O(L‐cys)12]and Ln0.33[Ln4(OH)4(OAc)3(H2O)7][Rh4Zn4O(L‐cys)12] for early and late lanthanides, respectively. While
the Ln3+ ions in Ln2[Rh4Zn4O(L‐cys)12] exist as disordered aqua species, those in
Ln0.33[Ln4(OH)4(OAc)3(H2O)7][Rh4Zn4O(L‐cys)12] form ordered hydroxide‐bridged cubane clusters thatconnect [Rh4Zn4O(L‐cys)12]6− anions in a 3D metal‐organic framework through coordination bonds withcarboxylate groups. This study shows the utility of an anionic metallosupramolecular framework withcarboxylate groups for the creation of a series of metal cubanes that have great potential for various
applications, such as magnetic materials and heterogeneous catalysts.
Unravelling the Role of Metallic Cu in Cu-CuFe2O4/C Nanohybrid for Enhanced Oxygen
Reduction Electrocatalysis
Biraj Jyoti BORAH, Yusuke YAMADA, Pankaj BHARALIACS Appl. Energy Mater., Vol. 3, pp. 3488-3496 (2020)
Interface engineering of metal and semiconductive spinel oxides is an efficient approach to improve
conductivity and ultimately boosting electrocatalytic property. Herein, we present the synthesis of CuCuFe2O4 nanohybrid coupled with conductive carbon (Cu-CuFe2O4/C) as a highly efficientelectrocatalyst for oxygen reduction reaction (ORR). The metallic Cu and semiconductive oxide CuFe2O4
interface provides better electronic conductivity, and carbon matrix offers conductive support forelectron/ion transfer process. Consequently, the Cu-CuFe2O4/C electrode exhibits superior current density(4.35 mA cm–2) in comparison to the standard Pt/C (3.81 mA cm–2) along with other catalyst systems
toward ORR. Thus, the nanohybrid that combines the advantages of metallic Cu and chemical interactionof carbon matrix along with its magnetic behavior establishes remarkable enhancement in ORR activity.
Furthermore, it also exhibits superior mechanical and electrochemical stability compared to that of Pt/C.
Thus, the unique structural design offers a new approach for the fabrication of magnetic metal-oxides
electrodes with enhanced ORR performance via interface engineering.
Relationship between Changes in Ionic Radius and Lattice Dimension of Lithium Manganese Oxide
Spinels during Lithium Insertion/Extraction
Kingo ARIYOSHI, Hiroya YAMAMOTO, Yusuke YAMADA
Solid State Ionics, Vol. 343, Article No. 115077 (5 pages) (2019)
Dimensional stability is critical for the cyclability of Li insertion materials in Li-ion batteries. Thus, inthis study, we characterize the dimensional change in a series of spinel-structured Li-Co-Mn oxides(LiCoxMn2-xO4) during Li insertion using ex-situ X-ray diffraction technique. We deduce that a change inthe cubic lattice parameters of the LiCoxMn2-xO4 compounds during Li insertion depends on the solidstate redox reactions; in particular, a smaller dimensional change is observed for the Co3+/Co4+ redox－34－reaction, while a larger change is observed for the Mn3+/Mn4+ redox reaction. Through our X-ray
diffraction studies, a linear relationship between the change in ionic radii of the redox species anddimensional change in the lattice structure of the compounds was observed during the reactions, which
can be adopted for other Li-Mn oxide spinels as well. Hence, this relationship provides useful insight for
designing Li insertion materials with high dimensional stability for long-life Li-ion batteries.
Elucidation of the Origin of Voltage Hysteresis in xLi2MnO3∙(1-x)LiCoO2 using Backstitch ChargeDischarge Method
Kingo ARIYOSHI, Takayuki INOUE, Yusuke YAMADAElectrochim. Acta, Vol. 334, Article No. 135623 (8 pages) (2020)
Lithium-excess (LEX) materials with a composition of xLi2MnO3∙(1-x)LiMO2 (M = Fe, Co, or Ni) exhibit
large reversible capacities and are therefore promising positive electrode materials for Li-ion batteries.
However, the widespread application of these materials is hindered by their large voltage hysteresis,
cycling-induced voltage decay, and long initial-cycle voltage plateau. Herein, Co-LEX materials with thecomposition of xLi2MnO3∙(1-x)LiCoO2 are synthesized and electrochemically characterized using thebackstitch charge-discharge method to elucidate the origin of voltage hysteresis. A trade-off relationshipbetween reversible capacity and energy efficiency is observed, and both reversible capacity and voltage
hysteresis extent increase with increasing Mn content. Quantitative analysis of voltage hysteresis by thebackstitch charge-discharge method reveals that the energy loss per cycle due to the difference inreversible potentials during charge and discharge is proportional to oxide redox reaction-derived capacity,which indicates that voltage hysteresis is caused by the solid-phase redox reactions of lattice oxide ions.
Thus, electrode potentials of solid-state oxide redox reactions are necessary to be matched in order toachieve both high reversible capacity and low voltage hysteresis for LEX materials.
Mechanism of Mg Extraction from MgMn2O4 during Acid Digestion
Kingo ARIYOSHI and Shumpei MASUDA
Phys. Chem. Chem. Phys., Vol. 22, pp. 4677-4684 (2020)
MgMn2O4 having a spinel structure is a very attractive material for the positive electrode in Mg-ion
batteries, since its reversible Mg extraction/insertion reaction can lead to a large reversible capacity. While
the Mg extraction from MgMn2O4 has been reported, the reaction mechanism remains unclear. In thispaper, Mg ions were chemically extracted from MgMn2O4 by acid digestion at various concentrations to
produce MgxMn2O4 (0 < x < 1). The results showed that Mg extraction from MgMn2O4 is a two-step twophase reaction, via the intermediate Mg0.5Mn2O4 to the fully oxidized Mn2O4. The kinetics of Mg
extraction was clarified using acid digestion experiments of different durations, and the direct reaction
pathway of MgMn2O4 oxidation to λ-MnO2 was the fastest process. This may explain the difficulty in Mg
extraction from MgMn2O4 using electrochemical methods.
Improvement of Float Charge Durability for LiCoO2 Electrodes under High Voltage and Storage
Temperature by Suppressing O1-Phase Transition
Motoyuki HIROOKA, Tomohito SEKIYA, Yoshitomo OMOMO, Masayuki YAMADA, Hideaki
KATAYAMA, Takefumi OKUMURA, Yusuke YAMADA, Kingo ARIYOSHI
J. Power Sources, Vol. 463, Article No. 228127 (7 pages) (2020)
To produce electronic devices with high functionality and longer operating times, the energy density oflithium ion batteries (LIBs) has to be increased while maintaining a long battery life and high reliability.
The energy density of LIBs can be increased by increasing the charge cut-off voltage. The float charge
durability of LIBs containing LiCoO2 under high voltage is one of the most important issues in practicaluse. The leakage current during float charge conditions is caused by the O1 phase transition of LiCoO2.
In this study, metal-substituted lithium cobalt oxides, LiCo1-xMxO2 (M = Co, Ni, Al, Mg, and Zr), were
investigated to suppress degradation during float charge conditions. When Ni was substituted for Co at
an amount of 5%, the float charge durability improved more than 4 times compared to bare-LiCoO2
without lowering the energy density. According to the structural analysis, we proposed the mechanism
for improving float charge durability by LiCo1-xNixO2; Ni ions partially migrate to the lithium layer andthen stabilize the O3 structure. This Ni ions substitution in LiCoO2 greatly contributes to extending life
and the safety of high energy density LIBs containing layered positive materials.
Reaction Mechanism and Kinetic Analysis of the Solid-State Reaction to Synthesize Single-Phase
Li2Co2O4 Spinel－35－Kingo ARIYOSHI, Kazuki YUZAWA, Yusuke YAMADA
J. Phys. Chem. C, Vol. 124, pp. 8170-8177 (2020)
Lithium cobalt oxide has two polymorphs that display different electrochemical properties despite theiridentical redox reactions: a high temperature phase having a layered structure (LiCoO2; HT-LCO) and a
low temperature phase with a spinel framework (Li2Co2O4; LT-LCO). The synthetic conditions of thesingle-phase LT-LCO were determined by thermogravimetric analysis performed on the solid-state
reaction of Li2CO3 and Co3O4. The results revealed that LCO synthesis was a second-order reaction withan activation energy of Ea = 150 kJ mol−1 and a pre-exponential factor of A = 9.2 × 107 s−1. XRD studies
indicated that low-temperature synthesis below 350 °C is necessary to obtain the single-phase LT phasebecause the HT phase fraction increased with increasing synthesis temperature. Virtually single-phase
LT-LCO obtained by calcining at 325 °C for 240 h exhibited zero-strain lithium insertion. These results
contribute toward the establishment of a synthetic method for novel materials with reduced spinel
structure.
Self-Discharge Tests to Measure Side-Reaction Currents of a Li[Li1/3Ti5/3]O4 Electrode
Kingo ARIYOSHI, Takahide TODA, Yusuke YAMADA
J. Electroanal. Chem., Vol. 864, Article No. 228127 (5 pages) (2020)
The lifetime performance of lithium-ion batteries is a critical issue for automobile and stationary
applications. The difference in the side-reaction current (ISR) of electrodes causes deviations of the stateof charge (SOC) of the electrodes leading to the capacity fading of lithium-ion batteries. Establishmentof a method to measure the ISR is important for understanding the capacity fading mechanism. We reportherein that a novel and simple method to determine the ISR in lithium-ion batteries, the self-discharge
test, was developed and applied to lithium-ion cells with lithium titanium oxide (Li[Li1/3Ti5/3]O4, LTO),
lithium aluminum manganese oxide (Li[Li0.1Al0.1Mn1.8]O4, LAMO), and lithium nickel manganese oxide(Li[Ni1/2Mn3/2]O4, LiNiMO) as electrodes. According to the self-discharge test results, the ISR of LTO isaffected by another electrode of LAMO or LiNiMO. The ISR of LTO in LTO/LiNiMO cells larger thanthat in LTO/LAMO cells is explained by the additional-ISR of LTO, which results from side reactions suchas the reduction of oxidized products generated at the positive electrode. The side reactions at the positiveelectrode are accelerated with increasing electrode potential, meaning that the higher potential of thepositive electrode resulted in the larger additional-ISR of LTO. The real side-reaction current of the LTO
electrode in lithium-ion cells is the sum of the intrinsic and the additional current (real-ISR = intrinsic-ISR+ additional-ISR).
Examining the Long-Term Cyclabilities of Li[Ni1/2Mn3/2]O4 and Li[Li0.1Al0.1Mn1.8]O4 Using a FullCell Configuration Including LTO-Counter Electrodes with Extra Capacity
Kingo ARIYOSHI, Makoto EGUCHI, Motoyuki HIROOKA
J. Electrochem. Soc., Vol. 167, Article No. 060532 (5 pages) (2020)
In this study, a novel cell configuration was developed for evaluating the cyclabilities of lithium insertionmaterials. In this cell, the Li[Li1/3Ti5/3]O4 (LTO) counter electrode has excess capacity on both the charge
and discharge sides (EQ-LTO). The EQ-LTO/Li[Ni1/2Mn3/2]O4 (LiNiMO) cell shows superior cyclability
when compared to other cell configurations, such as Li/LiNiMO and LTO/LiNiMO cells. In Li/LiNiMO
cells, drastic capacity fading is observed within 100 cycles. While LTO/LiNiMO cells are suited for longterm use, capacity fading occurs mainly due to the different charge states of LTO and LiNiMO rather thanthe deterioration of LiNiMO. Herein, long-term (more than 6 months) cycling tests are performed for
Li[Li0.1Al0.1Mn1.8]O4 (LAMO) in an EQ-LTO cell to assess whether this cell configuration is suitable for
evaluating long term cyclabilities; LAMO in this cell shows higher capacity retention than that in an LTO
cell. The capacity fading as a function of cycle number is found to be very small for LAMO (10 ppm
cycle−1). From these results, we concluded that the EQ-cell configuration provides accurate capacity
fading values for lithium insertion materials.
Scanning and Full Field X-Ray Fluorescence Imaging with Laboratory X-ray Source
Kouichi TSUJI, Momotaro NAKANISHI, Ryouta OZEKI, Tsugufumi MATSUYAMA
Extended Abstract of PSA-19(review), Journal of Surface Analysis, Vol. 26, No. 2, pp. 116-117 (2019)
Many applications of x-ray fluorescence (XRF) analysis have been reported in various fields, such as in theenvironmental, archeological, biological, and forensic sciences as well as in industry. Elemental analysis nearsurface region is performed by XRF. Advanced x-ray focusing optics such as polycapillary optics enables amicro x-ray beam with a laboratory x-ray source, leading to micro-XRF analysis and scanning-mode XRF－36－imaging. A confocal micro-XRF technique has been applied for the visualization of elemental distributions
inside the samples. In parallel, the authors have studied a wavelength dispersive XRF (WDXRF) imaging
spectrometer for a fast elemental imaging. A full-field energy dispersive X-ray fluorescence (FF-EDXRF)
imaging spectrometer using single photon counting analysis with xray camera was also studied. We evaluatedand discussed the performance of laboratory-made these scanning- and FFimaging spectrometers concerningenergy resolution, spatial resolution, quantitative performance and elemental imaging. At the end, compressedsensing which is one of general information processing technique was applied for high-resolution XRF images.
Depth Elemental Imaging during Corrosion of Hot-Dip Galvanized Steel Sheet by Confocal Micro XRF
Analysis
Koji AKIOKA, Takashi DOI, Shohei MITA, Tsugufumi MATSUYAMA, Kouichi TSUJI
Analytical Sciences, Vol. 36, pp 55-59 (2020)
The elucidation of the mechanism for steel corrosion under a coating layer has been attracting researchattention. Herein, we utilized a confocal micro-X-ray fluorescence (XRF) analytical instrument to conduct
non-destructive elemental obtained without sample destruction. To confirm corrosion suppression in thepresence of Mg ions, we observed the corrosion behavior of hot-dip galvanized steel sheets immersed in an
aqueous NaCl solution to which Mg ions were added. By using the confocal micro XRF system, the elutionof the coating components and the precipitation process of the corrosion products were confirmed.
Development of Full-field XRD (FFXRD) Imaging Method Realized in the Laboratory Using a Straight
Polycapillary and in situ Observation of the Oxidation Process of Cu by Heat Treatment
Masaki YAMANASHI, Kouichi TSUJI
e-Journal of Surface Science and Nanotechnology, Vol. 18, pp. 1−7 (2020)
We developed a full-field X-ray diffraction (FFXRD) imaging method using a straight polycapillary realized
in the laboratory that can obtain X-ray diffraction (XRD) images with a large area in a short time throughout
the simple process without the synchrotron radiation facility. The FFXRD imaging instrument can obtain the
XRD images of several millimeter sizes in several hundreds of seconds at each lattice plane. The positional
resolution and the spatial resolution was improved by using a straight polycapillary with long type. The
FFXRD imaging instrument was attached to the heat treatment system and Cu plate was heat-treated at 300°C.
As an example of in situ monitoring of the change in the crystal structure distribution, a high-temperatureoxidation process of Cu was observed. The XRD images of Cu, Cu2O, and CuO at each lattice plane wereobtained every hour. While the crystal structure distribution of Cu was reduced, the crystal structure
distribution of Cu2O and CuO were increased with the oxidation process of Cu by the heat treatment. Thechange of the crystal structure distribution near the surface by the oxidation process of Cu was confirmed. The
XRD image obtained by the FFXRD imaging instrument was analyzed by micro-XRD measurements andconfirmed that the FFXRD imaging instrument can accurately obtain the crystal structure distribution. In orderto obtain the XRD image with a large area, the FFXRD imaging instrument that can be realized in thelaboratory has advantages regarding the exposure time of X-rays and in situ analysis.
Super Resolution Analysis of X-ray Fluorescence Imaging Using Compressed Sensing Technique
Tsugufumi MATSUYAMA, Aoi YAMAUCHI, Masahiro IWASAKI, Kazunori HAYASHI, Kouichi TSUJI
Adv. X-Ray. Chem. Anal., Japan, Vol.51, pp. 49-56 (2020) (in Japanese)
Full field type X-ray fluorescence analysis is useful technique for obtaining element distribution images byusing 2D camera. This method is expected to be applied to various fields, however it is required to improve
the resolution of elemental images. Therefore, we aimed to obtain high-quality elemental distribution images
by applying a compressed sensing technique to full-field X-ray fluorescence imaging. In this paper, usefulnessof the analytical method was demonstrated by showing the elemental images of a metal sample composed ofcopper and titanium plates.
Improvement of Spatial Resolution of Micro-XRF Instrument by Shifted Confocal Micro-XRF
Configuration
Kazuhiko NAKANO, Shintaro KOMATANI, Atsushi BANDO, Hiroshi UCHIHARA, Kouichi TSUJI
Adv. X-Ray. Chem. Anal., Japan, Vol.51, pp. 57-63 (2020) (in Japanese)
An improvement of spatial resolution of micro-XRF by a “shifted confocal micro-XRF configuration” wasinvestigated. In the shifted confocal configuration, the focus points on the incident side and the detection side
are intentionally shifted from the conventional confocal setup, and the area where both the focal points coincidewith each other is narrowed to improve the spatial resolution. Although the obtained XRF intensities were－37－

reduced, the spatial (depth and in-plane) resolutions were improved by more than 10%.
Trace Element Analysis Using Total Reflection X-ray Fluorescence Spectrometry and Research Trendsof the Countries ~TXRF2019 Conference Report~
Tsugufumi MATSUYAMA, Yukie IZUMOTO, Hiroshi YOSHII, Kouichi TSUJI
Adv. X-Ray. Chem. Anal., Japan, Vol.51, pp. 261-270 (2020) (in Japanese)
Monochromatic Confocal Micro X-Ray Fluorescence Spectrometry
Naoki KAWAHARA, Shota SONODA, Shohei MITA, Tsugufumi MATSUYAMA, Kouichi TSUJI
Advances in X-ray Analysis, Vol. 63, pp. 125-131 (2020)
Confocal micro x-ray fluorescence (CM-XRF) spectrometry enables non-destructive elemental analysis,
allowing collection of 3D spatially resolved data to probe the inside of samples. In laboratory CM-XRF
instruments, polychromatic x-ray focusing sources formed by using an x-ray tube and a polycapillary full-lens
optic have been utilized. In this case, high background is one of the problems for trace elemental analysis. In
this paper, we report the preliminary results from a CM-XRF using a monochromatic source. Clear XRF
elemental images were obtained with low background.
Development of Fly-scan mode Confocal Micro X-ray Fluorescence Analysis
Tsugufumi MATSUYAMA, Shohei MITA, Momotaro NAKANISHI, Kouichi TSUJI
Advances in X-ray Analysis, Vol. 63, pp. 132-139 (2020)
Confocal micro-X-ray fluorescence (CM-XRF) is a useful technique for 3D element mapping of various typesof samples. In CM-XRF, a micro X-ray beam is generated through optical focusing of X-rays. Thus far, CMXRF has only been performed in step-by-step mode, with the drawback of prolonged measurement times
required for elemental mapping, depending on the area being measured. In our study, we have applied CMXRF in fly-scan mode, where continuous XRF is performed simultaneously with sample scanning. Because
fly-scan mode collects XRF data during the sample scanning stage without stopping the motor at illumination
spots, elemental mapping is achieved in a shorter time compared with the conventional method. In this study,
a copper plate was selected as the illumination sample, and its profiles were measured using fly-scan and stepby-step CM-XRF methods. In fly-scan mode, the sample stage motor was moved at four different speeds, andwe found that more distinct profiles were obtainable at lower scanning speeds. The copper profile was obtained
within approximately 30 min with fly-scan mode, while step-by-step mode required approximately 150 min.
Therefore, by employing CM-XRF with fly-scan mode, it is possible to produce clear elemental profiles in ashort scanning time.
Elemental Mapping of Pasta Sample Using Confocal Micro X-Ray Fluorescence Spectrometry
Hitomi NAKANO, Yumiko NAKANISHI, Shohei MITA, Momotaro NAKANISHI, Shintaro KOMATANI,
Kouichi TSUJI
Advances in X-ray Analysis, Vol. 63, pp. 140-150 (2020)
X-ray fluorescence (XRF) spectrometry enables non-destructive elemental analysis. In this paper, we
visualized chlorine (Cl) distribution in boiled pasta by using confocal micro X-ray fluorescence (C-M-XRF).
C-M-XRF can obtain 3D mapping images. A problem is that XRF from the inner area of sample is suscetible
to absorption. It was found that the XRF intensity of Cl was higher on the surface of the pasta and lower at thecenter. It was identified that Cl was detected at 300 μm depth by C-M-XRF. In this study, we corrected theinfluence of the XRF absorption effect inside the sample when confocal X-ray fluorescence analysis was used.
It was confirmed that the Cl distribution of the C-M-XRF was consistent with the Cl distribution of sample
cross section measured by the conventional micro-XRF. Therefore, we conclude that CM-XRF is an effective
non-destructive method for the evaluation of salt penetration near the surface of food samples.
Concept model of atomic hydrogen dry developing process for photolithographic patterning
Yuki Takemori, Masao GOHDO, Yuta KODA, Hideo HORIBE
AIP Advances, Vol.10, Article No.105223 (2020)
Atomic hydrogen dry etching was used for microstructure fabrication. Photolithography was proposed andachieved by a dry development process using atomic hydrogen irradiation. The reaction system of poly(methyl
methacrylate) mixed with molecular benzophenone was examined as a model system for a proof-of-concept
study. Optical patterning was experimentally made on a thin layer of poly(methyl methacrylate) withbenzophenone by UV light exposure with a photomask. The reaction system acted as a negative tone resist in
the proposed process. Thus, a model system for a new atomic hydrogen dry development process was proposed－38－

and successfully demonstrated.
Effect of pgsE expression on the molecular weight of poly (γ-glutamic acid) in fermentative production
Ken-Ichi FUIJITA, Takashi TOMIYAMA, Takahiro INOI, Takashi MISHIYAMA, Eriko SATO, Hideo
HORIBE, Ryosuke TAKAHASHI, Shinichi KITAMURA, Yoshihiro YAMAGUCHI, Akira OGITA, Toshio
TANAKA
Polymer J., in print (2020)
Poly(γ-glutamic acid) (PGA) is a biopolymer produced by Bacillus spp. via the γ-amide linkages of Dand/or L-glutamate. Although high-molecular-weight (HMW) PGA possesses many attractive properties, suchas flocculating, wound healing, and immune-stimulating effects, no studies have reported factors useful forincreasing the molecular weight of PGA during microbial production. PgsB, PgsC, and PgsA are the minimum
protein sets required for PGA production in B. subtilis, and PgsE improves PGA productivity. Analysis by sizeexclusion chromatography combined with multiangle laser light scattering revealed that the molecular weightof PGA was Mw = 2,900,000 g mol−1 and predominantly Mw = 47,000 g mol−1 in preparations derived from B.
subtilis cells with and without pgsE, respectively. PgsE may be required to increase the molecular weight of
PGA.
Thermoresponsive Conductivity of Acrylamide-Based Polymers and Ni Microparticle Composites
Hayato ONISHI, Yuta KODA, Hideo HORIBE
Chem. Lett., vol.49(10), in print (2020)
Composite materials with polymers and inorganic fillers enable the preparation of a variety of functional
polymer materials. In particular, composites with crystalline polymers and Ni microparticles (NiMPs) can beapplied to thermoresponsive conductive materials which are called PTC (positive temperature coeffcient)materials. These materials are conductive around room temperature, and turn to insulators at high temperature.
This phenomenon is induced by the volume expansion of the crystalline domains, therefore, the design ofmatrix polymers has been limited. Herein, we showed PTC phenomena by using polyacrylamide-based(co)polymers in lieu of crystalline polymers. Those materials showed PTC phenomena regarding conductivity
probably owing to the hydrogen bonding, yet polyacrylamides are amorphous polymers.
Microanalysis of Single Poly(N-isopropylacrylamide) Droplet Produced by an Optical Tweezer in
Water: Isotacticity Dependence of Growth and Chemical Structure of the Droplet
Kenta USHIRO, Tatsuya SHOJI, Mitsuhiro MATSUMOTO, Taka-Aki ASOH, Hideo HORIBE, Yukiteru
KATSUMOTO, Yasuyuki TSUBOIJ. Phys. Chem. B, vol.124(38), pp8454–8463 (2020)
Thermoresponsive phase separation mechanisms of aqueous poly(N-isopropylacrylamide) (PNIPAM)
solutions were investigated using an optical tweezer combined with a Raman microspectroscope. A nearinfrared laser beam (λ = 1064 nm) was focused into the solution to produce and trap a single polymer
microdroplet under an optical microscope. The laser beam played two important roles: The first role is tolocally heat the solution to induce phase separation in which numerous polymer microdroplets are generated
around the focus, while the second one is to collect these microdroplets. Eventually, a single polymer droplet
was stably produced and trapped at the focus. Our method enabled us to perform two types of microanalysis
for the droplet. Analysis I is real-time monitoring the growth of the polymer droplets by which we candetermine the growth rate of droplets. Analysis II is Raman microspectroscopy to reveal chemical componentsof the droplets. By means of these two analyses, we revealed important phase separation mechanisms in termsof stereoregularity (isotacticity) dependence. From analysis I, we show that droplet growth is governed by the
Ostwald ripening mechanism and the growth is accelerated by increasing the isotacticity. From analysis II, weshow that the gelation is promoted in the droplet (physical gel formation) with increasing isotacticity. Our
technique should be a versatile tool to explore liquid–liquid phase separation mechanisms for various binary
solution systems.
Effects of Nitrogen Dilution on the Photoresist Removal Rate by Hydrogen Radicals
Masashi YAMAMOTO, Hiroto NISHIOKA, Koki AKITA, Shiro NAGAOKA, Hironobu UMEMOTO, Hideo
HORIBE
J. Photopolymer Sci. and Technol., vol.33(4), pp427-431(2020)
We have previously demonstrated that photoresist removal rate comparable to oxygen plasma is accomplishedby optimizing the removal conditions with H radicals produced on hot metal filament surfaces from
H2/N2 mixtures (H2:N2 = 10:90 vol%). N2 gas was used to dilute the concentration of the H2 gas and to reduce－39－the risk of explosion. However, it is not clear how the dilution of H2 by N2 affects the removal rate. In thispaper, we examined the relationship between the removal rate and the H2 content; the flow rate ratio of H2 to
H2+N2. The removal rate increased with increasing the H2 content. In addition, the removal rate increased withincreasing the substrate temperature according to an Arrhenius equation, when the H2 content was over 90%.
However, below 60%, the removal rate decreased with increasing the temperature over 230 ± 5 ℃.
Denaturation of photoresist, e.g. hardening and/or crosslinking, may be induced by substrate heating when the
H-radical density is low. The removal rate decreases not only by the deficiency of H radicals but also by the
denaturation of films in H2/N2 mixed systems.
Evaluation of Decomposition Property of Photoresist by Oxygen Radicals Using Helium-Oxygen
Mixtures
Masashi YAMAMOTO, Koki AKITA, Koki AKITA, Shiro NAGAOKA, Hironobu UMEMOTO, Hideo
HORIBE
J. Photopolymer Sci. and Technol., vol.33(4), pp433-437(2020)
We have previously demonstrated that photoresist removal rate is enhanced by adding a trace amount of O 2 tothe atmosphere in which H radicals are produced from H2 on a hot metal filament. In this case, not only H
radicals but also O and OH radicals are produced. The populations of O and OH radicals are a few hundredthparts of that of H radicals, but these radicals must play important roles. It is not clear which radicals contribute
more to the enhancement of the removal rate. We used He/O2 mixtures in this study, instead of H2/O2, to
produce O radicals without co-producing H and OH to make clear the contribution of O radicals on the removal
rate. The removal rate increased slightly with increasing the O2 additive amount when the filament was
unheated. This may be caused by thermal oxidation. On the other hand, the removal rate with a hot filamentdecreased by the addition of O2. In short, the removal rate is not enhanced by O radicals. The enhancement in
H2/O2 mixtures must only be ascribed to OH radicals.
Facile Synthesis of Graft Copolymers Containing Rigid Poly(dialkyl fumarate) Branches byMacromonomer Method
Eriko SATO, Noboru TAMARI, Hideo HORIBE
J. Polym. Sci.: Part A, Polym. Chem., Vol. 40(24), pp. 2474-2480 (2019)
Graft copolymers show microphase separated structure as seen in block copolymers and have lower intrinsic
viscosity than block copolymers because of a branching structure. Therefore, considering molding
processability, especially for polymers containing rigid segments, graft copolymers are useful architectures. In
this work, graft copolymers containing rigid poly(diisopropyl fumarate) (PDiPF) branches were synthesized
by full free‐radical polymerization process. First, synthesis of PDiPF macromonomers by addition‐
fragmentation chain transfer (AFCT) was investigated. 2,2‐Dimethyl‐4‐methylene‐pentanedioic acid dimethyl
ester was found to be an efficient AFCT agent for diisopropyl fumarate (DiPF) polymerization because of the
suppression of undesired primary radical termination, which significantly took place when common AFCT
agent, methyl 2‐(bromomethyl)acrylate, was used. Copolymerization of PDiPF macromonomer with ethyl
acrylate accomplished the generation of the graft copolymer having flexible poly(ethyl acrylate) backbone andrigid PDiPF branches. The graft copolymer showed a microphase separated structure, high transparency, andcharacteristic thermal properties to PDiPF and poly(ethyl acrylate).
Synthesis and Evaluation of Thermally Curable Hyperbranched Polymers with Low Glass Transition
Temperature
Izumi UEHARA, Seidai OKADA, Hideo HORIBE, Eriko SATO
Journal of Network Polymer, Japan, Vol. 41(3), pp. 113-120 (2020) (in Japanese)
Network polymers show excellent properties such as a high mechanical strength and solvent resistance. On theother hand, the removal of network polymers is difficult due to insolubility. In order to solve the issue, decross-linkable network polymers have attracted much attention. In this review, the design of network polymers
having degradable units is introduced with focusing on the main-chain degradable polyperoxides-based
network polymers and curable hyperbranched polymers having dense degradable linkages. Curable adhesives
are one of the applications of network polymers, and de-cross-linkable network polymers can be used as
dismantlable adhesives, which demonstrate both sufficient bonding strength in use and easy debonding on
demand. Increase in bonding strength by the network formation and debonding by decreasing a mechanicalstrength and solubilization in response to de-cross-linking are reported.
Tuning of Optical Properties and Thermal Cycloreversion Reactivity of Photochromic Diarylbenzene－40－

by Introducing Electron-Donating Substituents
Tatsumoto NAKAHAMA, Daichi KITAGAWA, Seiya KOBATAKE
J. Phys. Chem. C, Vol. 123(51), pp. 31212-31218 (2019).
Thermally reversible photochromic compounds having excellent physicochemical properties can be exploitedfor many practical applications, such as ophthalmic lenses, real-time holography, and super-resolution
microscopy. In this study, we have designed and synthesized novel 1,2-diarylbenzene derivatives bearing
various electron-donating substituents at the p-position of the phenyl ring to tune the optical and thermal
properties for practical applications. The introduction of the electron-donating groups resulted in the red shiftof the absorption spectra, an increase in the absorption coefficients of the open-ring isomers, and decelerationof the thermal cycloreversion of the closed-ring isomers. Theoretical analysis based on Hammett’s substituent
constant and density functional theory revealed that the rate of thermal cycloreversion became lower inproportion to the electron-donating ability of the substituent. The novel 1,2-diarylbenzene derivatives
synthesized here could undergo photocyclization upon irradiation with UV-A light and fast thermal
cycloreversion with a half-life of a few hundred milliseconds to seconds.
Synthesis and Fluorescence On/Off Switching of Hyperbranched Polymers Having Diarylethene at the
Branching Point
Katsuya SHIMIZU, Rémi MÉTIVIER, Seiya KOBATAKE
J. Photochem. Photobiol. A: Chem., Vol. 390, Article No. 112341 (8 pages) (2020).
We designed and synthesized hyperbranched polymers (HBPs) having diarylethene (DE) at branching points
and having fluorene (FL) and DE derivatives between branching points in order to investigate the effect of thepolymer structure to fluorescence on/off switching efficiency induced by the photochromic reaction of DE.
First, HBP was synthesized by polymerization of an FL monomer (FL-St) in the presence of a DE monomerwith reversible addition-fragmentation chain transfer unit (St-DE-RAFT) in the feed ratio of [FL-St]/[St-DERAFT]=10. The fluorescence intensity of the resulting HBP decreased linearly as a function of thephotocyclization conversion of DE. The change in the fluorescence intensity accompanied by thephotochromic reactions indicates that one DE closed-ring isomer can quench 16.9 neighboring FL moieties.
However, the switching rate and on/off contrast of fluorescence were relatively low because the number of FL
in the polymer chain is much larger than that of DE. Therefore, we synthesized two types of HBPs having DE
positioned not only at the branching points but also integrated in the polymer chains with different branchingdegrees. The fluorescence intensity of FL for such HBPs showed a non-linear dependence on thephotocyclization conversion of DE, and a significant emission decrease with high on/off contrast even in low
conversion was demonstrated. One DE closed-ring isomer quenched 5.4–6.4 FL moieties, whereas thefluorescence quantum yield in the “on” state was found to be around 0.15. The quenching of FL molecules ismore pronounced for higher branching degrees in the polymers, indicating that DE closed-ring isomer canquench efficiently FL molecules when located within the polymer chains as well as at the branching points ofthe polymer.
A Dominant Factor of the Cycloreversion Reactivity of Diarylethene Derivatives as Revealed by
Femtosecond Time-Resolved Absorption Spectroscopy
Hikaru SOTOME, Kanako UNE, Tatsuhiro NAGASAKA, Seiya KOBATAKE, Masahiro IRIE, Hiroshi
MIYASAKA
J. Chem. Phys., Vol. 152(3), Article No. 034301 (9 pages) (2020).
Dynamics of the cycloreversion reaction of a photochromic diarylethene derivative with a small ring-opening
reaction yield (~1%) was investigated by using femtosecond transient absorption spectroscopy. The reaction
rate constant and activation barrier on the reaction coordinate were quantitatively analyzed on the basis of thetemperature and excitation wavelength dependencies of the reaction yield and excited state dynamics. Fromthe comparison of the present results with those in a more reactive derivative, we concluded that a key factor
regulating the overall reaction yield is the branching ratio at the conical intersection where the excited state
population is split into the product and the initial reactant. The excitation wavelength dependence of the
dynamics indicated that the geometrical relaxation and vibrational cooling proceed in a few picosecond timescale behind the cycloreversion process, and the vibrational excess energy assists the molecule to climb up theenergy barrier.
Synthesis and Multicolor Emission Properties of Polystyrene with Difluoroboron Avobenzone
Complexes at Side Chains
Katsuya SHIMIZU, Arisa OKUMA, Shiho KATSUMI, Fuyuki ITO, Seiya KOBATAKE－41－

Dyes and Pigments, Vol. 177, Article No. 108283 (7 pages) (2020).
Random copolymers (poly(ABSt-co-St)) consisting of avobenzone-BF2 complex monomer (ABSt) and styrene(St) were synthesized and used for emission color tuning including white-like emission in the solid state using
St units as a spacer. The emission color of ABSt in the resulting copolymers changed from green to blue via
bluish-white by changing the content of St. The fluorescence quantum yields of the polymers in the solid state
were relatively high (Φf = 0.30-0.51) independent of the composition contents. The polymers have two main
emission bands around 440 and 540 nm, which were derived from the emission of single-molecule andamorphous aggregation, respectively. The fluorescence color changed according to a change in the ratio of thefluorescence intensity at 440 and 540 nm (F440/F540). The absorption and fluorescence properties of thepolymers in tetrahydrofuran were independent of the composition ratio of ABSt and St, which indicates nointermolecular interaction between avobenzone-BF2 (AB) fluorophores in the intra-polymer chain. The
emission color of all polymers in the solution was blue and the fluorescence spectra were the same as that ofABSt in the solution. Thus, emission color changes observed in the solid state were mainly derived from theintermolecular interaction between AB fluorophores in inter-polymer chains because the polymers intertwined
each other in the solid state. When the polymers in the solid state were annealed, F440/F540 increased and all of
the fluorescence spectra became similar to that of monomer emission according to the arrangement change ofthe polymer chain. It is concluded that emission color changes of the polymers are mainly derived fromintermolecular interaction between AB fluorophores in the inter-polymer chains. We have demonstrated thatpoly(ABSt-co-St) forms excellent homogeneous fluorescence polymer films. In contrast, the mixture of
methoxy AB (ABOMe) and poly(St) undergoes crystallization even in the low content of ABOMe in poly(St).
Mechanical Actuation and Patterning of Rewritable Crystalline Monomer-Polymer Heterostructures
via Topochemical Polymerization in a Dual-Responsive Photochromic Organic Material
Ranita SAMANTA, Daichi KITAGAWA, Amit MONDAL, Manjima BHATTACHARYA, Mari
ANNADHASAN, Saikat MONDAL, Rajadurai CHANDRASEKAR, Seiya KOBATAKE, C. Malla REDDYACS Appl. Mater. Interf., Vol. 12(14), pp. 16856-16863 (2020).
The dark-orange monomer single crystals of 1,1′-dioxo-1H-2,2′-biindene-3,3′-diyldidodecanoate (BITdodeca2) convert to a transparent single-crystalline polymer (PBIT-dodeca2) material via a single-crystal-tosingle-crystal (SCSC) polymerization reaction under sunlight, which then undergoes reverse thermaltransformation into BIT-dodeca2 single crystals, leading to reversible photo-/thermochromism, coupled withmechanical actuation. We exploit the properties of this unique material to demonstrate the formation ofmonomer-polymer heterostructures in selected regions of single crystals with micrometer-scale precision usinga laser. This is the first example of heterostructure patterning involving monomer-polymer domains in single
crystals. We reveal that the speed of photomechanical bending induced by the polymerization reaction in thisexample is comparable to those of the well-known diarylethene derivatives, in which electrocyclic ring-closing
and ring-opening reactions operate. Furthermore, we characterize the distinct mechanical properties of themonomer and polymer using a quantitative nanoindentation technique as well as demonstrate photopatterning
on a monomer-coated paper for potential use in security devices. These crystals with several advantages, suchas photomechanical bending (weight lifting) even when the crystal size is large, responsiveness to both UV
and visible light, distinct solubilities (the polymer is insoluble, whereas the monomer is soluble in most organic
solvents) and colors, provide unique opportunities for their use at different length scales of the sample (μm tomm) for various purposes.
Improving Photosensitivity without Changing Thermal Reactivity in Photochromic Diarylbenzenes
Based on Accurate Prediction by DFT Calculations
Daichi KITAGAWA, Naoko TAKAHASHI, Tatsumoto NAKAHAMA, Seiya KOBATAKE
Photochem. Photobiol. Sci., Vol. 19(5), pp. 644-653 (2020).
1,2-Diarylbenzenes (DABs) have been developed as a new family of fast T-type photochromic switches.
However, the molecular design strategy for DABs with desired optical and thermal properties is not established.
In this work, we explored the best functional in quantum chemical calculations to predict the properties of
DABs. Furthermore, we newly designed and synthesized DABs based on the calculation using the best
functional, resulting in the improvement of the photosensitivity in the UV-A region (i.e. a shift of absorption
to lower energies and an increase in the absorption coefficient) without changing the thermal back-reactionrate.
Enhancement of Coloring under Ultraviolet Irradiation in Photochromic Diarylbenzenes
Shota HAMATANI, Daichi KITAGAWA, Tatsumoto NAKAHAMA, Seiya KOBATAKE－42－

Tetrahedron Lett., Vol. 61(24), Article No. 151968 (5 pages) (2020).
1,2-Diarylbenzenes have been developed as a new family of T-type photochromic switches that have potential
applications such as ophthalmic lenses, real-time holography, and super-resolution microscopy. In this work,
we have designed and synthesized novel diarylbenzenes bearing thiazole and oxazole rings as the aryl groups
to improve the coloring under ultraviolet (UV) irradiation. The substitution of the aryl groups with thiazole
and oxazole rings having lower aromaticity than thiophene brought about the deceleration of the thermal
bleaching reaction, the blue-shift of the absorption spectra of the closed-ring isomers, and the increase of thephotocyclization reactivity, which results in the enhancement of the coloring when exposed to UV light. The
results would provide useful information for the development of practical applications using diarylbenzene
chromophores.
Photoreversible Birefringence Change of Diarylethene Single Crystals as Revealed by Change in
Molecular Polarizability Anisotropy
Kohei MORIMOTO, Hajime TSUJIOKA, Daichi KITAGAWA, Seiya KOBATAKE
J. Phys. Chem. A, Vol. 124(23), pp. 4732-4741 (2020).
Stimuli-responsive organic crystals represent a new frontier of material chemistry. Recently, we have reported
photoreversible interference color change to multicolor in single crystals composed of a photochromic
diarylethene derivative, 1,2-bis(2-ethyl-5-phenyl-3-thienyl)perfluorocyclopentene (1a), accompanied by thephotochromic reaction. The origin of the interference color change is due to the photoinduced birefringencechange in the photoisomerization of diarylethenes. In this study, we newly found that single crystals composedof 1,2-bis(2,5-dimethyl-3-thienyl)perfluorocyclopentene (2a) also exhibit a photoreversible interference color
change. The birefringence value for crystal 2a increased with the photocyclization conversion, while that forcrystal 1a decreased. The relationship between the photoinduced birefringence changes for crystals 1a and 2aand their molecular structures was discussed based on the change in the molecular polarizability anisotropy
accompanied by the photochromic reaction. These results would provide not only new opportunities for theapplication of photochromic crystals but also useful strategies for the design of crystalline materials that exhibit
the desired birefringence change.
Nanosecond Laser Photothermal Effect-Triggered Amplification of Photochromic Reactions inDiarylethene Nanoparticles
Yukihide ISHIBASHI, Shoki NAKAI, Keisuke MASUDA, Daichi KITAGAWA, Seiya KOBATAKE,
Tsuyoshi ASAHI
Chem. Commun., Vol. 56(52), pp. 7088-7091 (2020).
Intense nanosecond 532-nm pulse laser excitation to aqueous nanoparticle colloids of a photochromic
diarylethene induced drastic amplification of the cycloreversion reaction yield depending on a laser fluence of
1 to 37 mJ cm−2 pulse−1. The conversion from the closed-ring form to the open-ring form by a single-shot
nanosecond pulse showed the third-order increase against the laser fluence. The enhancement of thecycloreversion quantum yield was discussed in terms of the transient laser heating of the nanoparticle in ananosecond time scale. We propose the nanoscale laser heating model where ultrafast photothermal conversion
enhances the cycloreversion reaction of molecules neighbouring an excited one. For this model, an intense
nanosecond-laser pulse plays two roles; one is to heat the nanoparticle composed of the closed-ring form
quickly and the second is to induce the cycloreversion reaction in the “hot” nanoparticle keeping thetemperature high during the nanosecond laser pulse. Consequently, a photosynergetic interaction between
multi-chromophore and multi-photon is indispensable for the drastic enhancement of the cycloreversion
reaction of the nanoparticle composed of the closed-ring form. Thus, the mechanism was explained as a‘photosynergetic response’ coupled with nanoscale laser heating and the photochemical reaction in
nanoparticles.
Geometrical Evolution and Formation of the Photoproduct in the Cycloreversion Reaction of a
Diarylethene Derivative Probed with Molecular Vibrations
Hikaru SOTOME, Hajime OKAJIMA, Tatsuhiro NAGASAKA, Yuka TACHII, Akira SAKAMOTO, Seiya
KOBATAKE, Masahiro IRIE, Hiroshi MIYASAKA
ChemPhysChem, Vol. 21(14), pp. 1524-1530 (2020).
The geometrical evolution of the reactant and formation of the photoproduct in the cycloreversion reaction ofa diarylethene derivative were probed using time-resolved absorption spectroscopies in the visible to nearinfrared and mid-infrared regions. The time-domain vibrational data in the visible region show that the initiallyformed Franck-Condon state is geometrically relaxed into the minimum in the excited state potential－43－

energy surface, concomitantly with the low-frequency coherent vibrations. Theoretical calculations indicatethat the nuclear displacement in this coherent vibration is nearly parallel to that in the geometrical relaxation.
Time-resolved mid-infrared spectroscopy directly detected the formation of the open-ring isomer with thesame time constant as the decrease of the closed-ring isomer in the excited state minimum. This observation
reveals that no detectable intermediate, in which the population is accumulated, is present between the excitedclosed-ring isomer and the open-ring isomer in the ground state.
Photoluminescence ON/OFF Switching of a Single Colloidal Quantum Dot Using Photochromic
Diarylethene
Nanoka YANO, Mitsuaki YAMAUCHI, Daichi KITAGAWA, Seiya KOBATAKE, Sadahiro MASUO
J. Phys. Chem. C, Vol. 124(31), pp. 17423-17429 (2020).
Photoluminescence (PL) on/off switching systems using photochromic molecules have a high potential for awide range of applications, such as optical memories, chemo- and biosensing, and super-resolution microscopy.
The combination of diarylethene derivatives (DAEs) and colloidal semiconductor quantum dots (QDs) is themost promising candidate system. The PL on/off switching behavior of the systems has been observed in
ensemble solutions. In this work, we investigated the PL on/off switching behavior of CdSe/ZnS core/shell
QDs at the single QD level by dispersing the QDs and DAEs in a poly(methyl methacrylate) thin film. The
photoswitching behavior of the PL intensity and the lifetime of single QDs accompanied by thephotoisomerization of the DAE were successfully observed based on Förster-type fluorescence resonanceenergy transfer (FRET) from the excited QDs to the closed-ring form of the DAEs. By controlling theconcentration of DAEs and the photoirradiation time for the photoisomerization of DAEs, average FRET
efficiency of approximately 80% was achieved. However, a completely reversible photoswitching was difficult
to achieve. Based on the PL lifetime change of the single QDs with the photoisomerization of DAEs, detailsof the system are discussed. The present results provide important insights into creating PL on/off switchingsystems using a single QD and photochromic molecules.
Symmetry Breaking and Photomechanical Behavior of Photochromic Organic Crystals
Daichi KITAGAWA, Christopher J. Bardeen, Seiya KOBATAKE
Symmetry, Vol. 12(9), Article No. 1478 (16 pages) (2020).
Photomechanical materials exhibit mechanical motion in response to light as an external stimulus. They haveattracted much attention because they can convert light energy directly to mechanical energy, and their motions
can be controlled without any physical contact. This review paper introduces the photomechanical motions ofphotoresponsive molecular crystals, especially bending and twisting behaviors, from the viewpoint ofsymmetry breaking. The bending (right-left symmetry breaking) and twisting (chiral symmetry breaking) of
photomechanical crystals are based on both intrinsic and extrinsic factors like molecular orientation in the
crystal and illumination conditions. The ability to design and control this symmetry breaking will be vital for
generating new science and new technological applications for organic crystalline materials.
Photomechanical Behavior of Photochromic Diarylethene Crystals, Chapter 1
Seiya KOBATAKE, Daichi KITAGAWA
Mechanically Responsive Materials for Soft Robotics, Ed.: H. Koshima, Wiley-VCH Verlag, pp. 3-28 (2020).
Photochromic compounds undergo photoreversible transformation reactions between two isomers having
different absorption spectra. Diarylethene derivatives exhibit photochromism even in the crystalline phase.
Photochromic crystals may be potentially useful for optoelectronic devices, such as optical memories,
photoswitchable color filters, photoswitchable polarizers, and photomechanical actuators. This chapter focuses
on recent development of photomechanical behavior of photochromic diarylethene crystals, as crystal
deformation, bending, twisting, and breaking.
Solid-State Fluorescence Switching Using Photochromic Diarylethenes, Chapter 15
Seiya KOBATAKE, Tatsumoto NAKAHAMA
Advances in Organic Crystal Chemistry, Comprehensive Reviews 2020, Eds.: M. Sakamoto, H. Uekusa,
Springer, Singapore, pp. 299-323 (2020)
Solid-state fluorescence-switchable materials that show large changes in fluorescence intensities and/or colors
in response to various external stimuli have attracted much attention in various applications, such as opticalmemories, display devices, and sensor materials. In particular, fluorescence switching using photochromic
diarylethenes has been widely investigated because of the excellent performance of diarylethene with highthermal stabilities, high fatigue-resistant properties, and high reactivity in the solid states. Although many－44－

researchers investigated the fluorescence switching properties only in solution, the evaluation in solid states isessential for the practical applications. This chapter has focused on solid-state fluorescence switching behavior
using diarylethene and reviewed the rational design and the properties for various types of the fluorescenceswitchable materials.
Photoresponsive Molecular Crystals for Light-Driven Photoactuators, Chapter 25
Seiya KOBATAKE, Daichi KITAGAWA
Photosynergetic Responses in Molecules and Molecular Aggregates, Eds.: H. Miyasaka, K. Matsuda, J. Abe,T. Kawai, Springer, Singapore, pp. 427-447 (2020)
Various types of photomechanical motion have drawn much attention because there is a potential to create
photomechanical actuators from molecular-scale to macro-scale. To construct photoactuators, it is necessary
to utilize a molecular assembly with a small free volume. Photochromic compounds undergo photoreversible
isomerization between the original colorless isomer and the photo-generated colored isomer upon alternating
irradiation with UV and visible light. Among many known photochromic compounds, diarylethenes undergophotochromic reactions even in the crystalline phase. The present review introduces recent development in the
study of photomechanical crystals including crystal shape changes, bending velocity, dependence of thebending behavior on irradiation wavelength, the behavior in mixed crystal, new types of photomechanicalmotion, and applications. These photomechanical behaviors are based on geometrical structure changes in the
crystalline phase and can be applied to macro-sized light-driven photoactuators.
Treatment of Wastewater Containing Persistent Organic Pollutants by Catalytic Hydrothermal
Oxidation Method
Noritsugu KOMETANI
Catalysts and Catalysis, Vol. 62, No. 3, p. 173-177 (2020)
Degradation of persistent organic pollutants contained in wastewater can be substantially facilitated using
copper-based materials as a catalyst for catalytic hydrothermal oxidation. The mechanism has been
attributed to the dramatic acceleration of Fenton-like reaction by copper ion under the hydrothermal
condition. Copper-nickel binary catalyst has been recently found to show a higher catalytic action.
Development of Advanced Wastewater Treatment Technique by Hydrothermal Oxidation Method
Noritsugu KOMETANI
Newletter of the Technical Association of Photopolymers, Vol. 90, p. 7-9 (2020)
Chemically Crosslinked Bispecific Antibodies for Cancer Therapy: Breaking from the Structural
Restrictions of the Genetic Fusion Approach
Asami UEDA, Mitsuo UMETSU, Takeshi NAKANISHI, Kentaro HASHIKAMI, Hikaru NAKAZAWA,
Shuhei HATTORI, Ryutaro ASANO, Izumi KUMAGAIInt. J. Mol. Sci., Vol. 21, Article No. 711 (15 pages) (2020)
Antibodies are composed of structurally and functionally independent domains that can be used as building
blocks to construct different types of chimeric protein-format molecules. However, the generally used genetic
fusion and chemical approaches restrict the types of structures that can be formed and do not give an ideal
degree of homogeneity. In this study, we combined mutation techniques with chemical conjugation to construct
a variety of homogeneous bivalent and bispecific antibodies. First, building modules without lysine residues—
which can be chemical conjugation sites—were generated by means of genetic mutation. Specific mutatedresidues in the lysine-free modules were then re-mutated to lysine residues. Chemical conjugation at therecovered lysine sites enabled the construction of homogeneous bivalent and bispecific antibodies from block
modules that could not have been so arranged by genetic fusion approaches. Molecular evolution andbioinformatics techniques assisted in finding viable alternatives to the lysine residues that did not deactivate
the block modules. Multiple candidates for re-mutation positions offer a wide variety of possible stericarrangements of block modules, and appropriate linkages between block modules can generate highly bioactive
bispecific antibodies. Here, we propose the effectiveness of the lysine-free block module design for sitespecific chemical conjugation to form a variety of types of homogeneous chimeric protein-format moleculewith a finely tuned structure and function.
Turn-on fluorescence and photodynamic activity of β-(1,3-1,6)-D-glucan-complexed porphyrinderivative inside HeLa cells
Shodai HINO, Rikushi FUNADA, Kouta SUGIKAWA, Kazuya KOUMOTO, Toshio SUZUKI, Takeshi－45－

NAGASAKI, Atsushi IKEDA
Photochem. Photobiol. Sci., Vol.18, pp. 2854-2858 (2019).
Fluorescence intensities of water-soluble β-(1,3-1,6)-D-glucan (β-1,3-glucan)-complexed porphyrinderivatives were very weak as a result of self-quenching. However, β-1,3-glucan-complexed tetra(aminophenyl)porphyrin exhibited ‘oﬀ-state’ to ‘on-state’ uorescence switching activity by intracellular
uptake. Furthermore, the internalised complex showed a high level of photodynamic activity toward HeLa
cells under photoirradiation at long wavelengths.
Improved Stability and Photodynamic Activity of Water-Soluble 5,15-Diazaporphyrins Incorporatedin β-(1,3-1,6)-D-Glucan with On-Off Switch
Shodai HINO, Shuhei SATAKE, Hideyuki SHINMORI, Kouta SUGIKAWA, Riku KAWASAKI, Kazuya
KOUMOTO, Toshio SUZUKI, Takeshi NAGASAKI, Atsushi IKEDA
Chemistry-An Asian Journal., Vol.15, pp. 365-370 (2020).
5,15-Diazaporphyrins, which have a large absorption at wavelengths over 600 nm, were dissolved in water bycomplex formation with β-(1,3-1,6)-D-glucans. Aqueous solutions of these complexes were relatively stablecompared with their trimethyl-β-cyclodextrin-complexed analogues. β-Glucan-complexed diazaporphyrins
showed quenched fluorescence and had low singlet-oxygen-generation abilities owing to random selfaggregation. However, external stimuli, such as the presence of liposomes or intra-cellular uptake, restored thefluorescenceandsinglet-oxygen-generation
abilitiesof β-glucan-complexeddiazaporphyrins.
Consequently, β-glucan-complexed diazaporphyrins showed very high photodynamic activities toward HeLa
cells.
Mechanism Toward Turn-on of Polysaccharide––Porphyrin Complexes for Fluorescence Probes andPhotosensitizers in Photodynamic Therapy in Living Cells
Shodai HINO, Rikushi FUNADA, Kouta SUGIKAWA, Riku KAWASAKI, Kazuya KOUMOTO, Toshio
SUZUKI, Takeshi NAGASAKI, Atsushi IKEDA
ChemMedChem, in press.
β-(1,3-1,6)-D-Glucan, λ-carrageenan, tamarind gum, and pullulan can dissolve various porphyrinderivatives via the formation of complexes in water using a high-speed vibration milling method. The
aqueous solutions of the resulting complexes exhibit long-term stability. Despite the adverse effects of theself-quenching process, notable fluorescence and improved photodynamic activity of the polysaccharidecomplexed porphyrin derivatives were observed in the presence of liposomes, micelles, cyclodextrins, andHeLa cells. It was noted that the type of porphyrins was more important than the type of polysaccharides
present in the complex. Porphyrin self-aggregates were monodispersed in the lipid membranes of theliposomes and lysosomes. The polysaccharide-complexed porphyrin derivatives showed increased
photodynamic activity toward HeLa cells under photoirradiation between 610 and 740 nm.
Preparation and Characterization of a Novel Bispecific Antibody That Targets Her2 and BSH for
Boron Neutron Capture Therapy
Taisei KANAI, Taro TACHIBANA, Takeshi NAKANISHI, Takeshi NAGASAKI, Mitsunori Kirihata,
Yoshihide HATTORI, Yu SANADA, Yoshinori SAKURAI, Shin-ichiro MASUNAGAKURNS Progress Report 2019, in press.
Construction of a Circularly Connected VHH Bispecific Antibody (Cyclobody) for the Desirable
Positioning of Antigen-Binding Sites
Saki HEMMI, Ryutaro ASANO, Kouki KIMURA, Mitsuo UMETSU, Takeshi NAKANISHI, Izumi
KUMAGAI, Koki MAKABE
Biochem. Biophys. Res. Commun., Vol. 523, pp. 72–77 (2020)
A bispecific antibody (bsAb) is an emerging class of next-generation biological therapeutics. BsAbs areengineered antibodies possessing dual antigen-binding paratopes in one molecule. The circular backbone
topology has never been demonstrated, although an enormous number of bispecific constructs have been
proposed. The circular topology is potentially beneficial for fixing the orientation of two paratopes andprotection from exopeptidase digestion. We construct herein a circularly connected bispecific VHH, termed
cyclobody, using the split-intein circular ligation of peptides and proteins. The constructed cyclobodies areprotected from proteolysis with a retained bispecificity. The anti-EGFR × anti-GFP cyclobody can specificallystain EGFR-positive cells with GFP. The anti-EGFR × anti-CD16 cyclobody shows cytotoxic activity against
EGFR-positive cancer cells with comparative activity of a tandem VHH construct. Successful demonstration－46－

of a new topology for the bispecific antibody will expand the construction strategy for developing antibodybased drugs and reagents.
Build-Up Functionalization of Anti-EGFR × Anti-CD3 Bispecific Diabodies by Integrating HighAffinity Mutants and Functional Molecular Formats
Ryutaro ASANO, Katsuhiro HOSOKAWA, Shintaro TAKI, Shota KONNO, Ippei SHIMOMURA, Hiromi
OGATA, Mai OKADA, Kyoko ARAI, Masayoshi ONITSUKA, Takeshi OMASA, Takeshi NAKANISHI,
Mitsuo UMETSU, Izumi KUMAGAI
Sci. Rep., Vol. 10, Article No. 4913 (8 pages) (2020)
Designing non-natural antibody formats is a practical method for developing highly functional next-generation
antibody drugs, particularly for improving the therapeutic efficacy of cancer treatments. One approach isconstructing bispecific antibodies (bsAbs). We previously reported a functional humanized bispecific diabody(bsDb) that targeted epidermal growth factor receptor and CD3 (hEx3-Db). We enhanced its cytotoxicity by
constructing an Fc fusion protein and rearranging order of the V domain. In this study, we created an additional
functional bsAb, by integrating the molecular formats of bsAb and high-affinity mutants previously isolatedby phage display in the form of Fv. Introducing the high-affinity mutations into bsDbs successfully increased
their affinities and enhanced their cytotoxicity in vitro and in vivo. However, there were some limitations toaffinity maturation of bsDb by integrating high-affinity Fv mutants, particularly in Fc-fused bsDb with intrinsic
high affinity, because of their bivalency. The tetramers fractionated from the bsDb mutant exhibited the highest
in vitro growth inhibition among the small bsAbs and was comparable to the in vivo anti-tumor effects of Fcfused bsDbs. This molecule shows cost-efficient bacterial production and high therapeutic potential.
Identification of yeast-derived emulsification proteins through analyses of proteins distributed into theemulsified phase
Masaya ONISHI, Mana UEDA, Daiki SAITO, Mao TAKATA, Yoshihiro OJIMA, Masayuki AZUMA
Food Hydrocoll., in press (2020)
Emulsifiers are widely used in food manufacturing, and cell wall mannoproteins from Saccharomyces
cerevisiae, a representative food yeast, have been proposed as potential new emulsifiers. However, their use
has not become widespread. One reason is that the protein responsible for emulsification has not been identified
so no efficient preparation method has been established. In this study, the emulsification substances wereidentified. Many mannoproteins are fixed to the cell wall via a glycosylphosphatidylinositol (GPI) anchor.
Because emulsifying activity was found in the culture supernatant (CS) in gup1Δ with a mutation of GPI anchor
synthesis, a protein distributed from the CS into the emulsified phase by emulsification treatment was analyzed.
Using mass spectrometry, it was identified to be Gas1, a mannoprotein localized to the cell wall via a GPI
anchor. Further, recombinant Gas1 without a C-terminal GPI anchor binding signal was purified, and it showed
activity similar to bovine serum albumin, a well-known protein emulsifier. Gas1 also retained its activity undera wide range of pH and high salt conditions. Saccharomyces cerevisiae has Gas3 and Gas5, proteinshomologous to Gas1, and recombinant Gas3 and Gas5 without the C-terminal signal were also purified andfound to have emulsifying activity similar to that of recombinant Gas1. These results strongly suggest that Gas
proteins take part in the emulsifying activity of yeast mannoproteins. It was also demonstrated thatemulsification proteins could be identified by analyzing proteins distributed in an emulsified phase, so thismethod will be effective in finding new emulsification proteins.
Enhanced floc formation by degP-deficient Escherichia coli cells in the presence of glycerol
Yoshihiro OJIMA, Hiroaki HONMA, Mio OTSUKA, Satsuki MATANO, Masayuki AZUMAJ. Biosci. Bioeng., in press (2020)
Floc formation is an aggregation phenomenon of microbial cells in which the cells form flocs. In this study, it
was found that addition of glycerol to a complex glucose medium promoted spontaneous floc formation by an
Escherichia coli degP-deficient mutant strain (ΔdegP) in a dose-dependent manner. In the presence of 10%(v/v) glycerol, the amount of floc formation (quantified as floc protein) reached its maximum value (230 mg/L),
five times that in its absence. 10% (v/v) glycerol was the limit concentration that does not inhibit cell growthof ΔdegP strain. Glycerol was not consumed by ΔdegP cells during floc formation. To provide media having
nearly the same viscosity as that containing 10% (v/v) glycerol, carboxymethyl cellulose (CMC) or
polyvinylpyrrolidone (PVP) were added to medium as viscosifying agents. Floc formation was not promoted
by increasing the medium viscosity with CMC or PVP. However, addition of ethylene glycol also significantly
promoted floc formation in the same manner as glycerol. Addition of short-chain polyols decreased the numberof viable ΔdegP cells in the floc structure and enhanced outer membrane vesicle (OMV) production by ΔdegP－47－

cells; polyols-induced damage of outer membrane in ΔdegP cells may contribute to the promoted floc
formation.
Mineralization induced by phosphorylated dry baker’s yeast
Yoshihiro OJIMA, Maya KIHARA, Mami YOSHIDA, Koichi IGARASHI, Tomoko YOSHIDA, Masayuki
AZUMA
PLOS ONE, Vol.15, No. 9, p. e0239774 (2020)
We found the mineralization of Cu during long-term Cu2+ adsorption onto dry baker’s yeast cells
phosphorylated using sodium cyclo-triphosphate. Field emission scanning electron microscopy (FESEM) withenergy-dispersive X-ray spectroscopy confirmed that the elemental composition of minerals were copper,
phosphorus, and oxygen. Synchrotron-based X-ray absorption fine structure showed that the local structurearound Cu atoms deposited on the mineral was almost identical to that of commercial copper (II) phosphate
Cu3(PO4)2∙3H2O. However, the crystallinity was low, and the structure was slightly distorted. Time profile
analysis using FESEM revealed that copper phosphate mineralization was first apparent on Day 3 of adsorption,
whereas mineral formation plateaued at around Day 7. It seems that mineralization occurs by the local
saturation of phosphate and Cu2+ on the yeast cells. Mineralization of the rare earth ion Dy3+ was also
demonstrated during long-term adsorption. Mineralization on phosphorylated yeast cells appears to follow acommon path for various types of metal ions and provides a promising technique for metal recovery via
irreversible adsorption.
Cell surface changes that advance the application of using yeast as a food emulsifier
Shinsuke NEROME, Masaya ONISHI, Daiki SAITO, Ayano MIZOBUCHI, Tatsuya ANDO, Yui DAIRA,
Azusa MATSUMOTO, Yoshihiro OJIMA, Masayuki AZUMA
Food Chem., Vol. 315, p. 126264 (2020)
A previous study revealed that Saccharomyces cerevisiae mcd4∆, a cell wall mutant with a defect in thesynthesis of the glycosylphosphatidylinositol anchor, has a strong macrophage activation ability. In this study,
remarkable emulsion formation after cell suspensions of mcd4∆ and anp1∆ (which exhibit an extreme
reduction of mannan) were mixed with oil was found. Moreover, the relationship between cell wall mutationand emulsion formation was investigated, suggesting that och1∆ with a defect in the formation of N-linked
glycans also had a strong emulsification ability and that high molecular weight materials released from thecells were involved in emulsion formation. Furthermore, two strains (asc1∆ and scp160∆) with a strong
emulsification ability without a large decrease in mannan content were also found from the wide screening ofstrains that exhibit an emulsifying activity using more than 5,000 gene-deficient strains. These results provide
valuable information for the development of a yeast-derived emulsifier.
Construction of hypervesiculation Escherichia coli strains and application for secretory protein
production
Yoshihiro OJIMA, Tomomi SAWABE, Katsuya KONAMI, Masayuki AZUMA
Biotechnol. Bioeng., Vol. 117, No. 3, pp. 701-709 (2020)
Outer membrane vesicles (OMVs) are extracellular vesicles released from the surface of Gram-negative
bacteria, including Escherichia coli. Several gene-deficient mutants relating to envelope stress (nlpI and degP)and phospholipid accumulation in the outer leaflet of the outer membrane (mlaA and mlaE) increase OMV
production. This study examined the combinatorial deletion of these genes in E. coli and its effect on OMV
production. The nlpI and mlaE double-gene-knockout mutant (ΔmlaEΔnlpI) showed the highest OMVproduction. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis-based quantitative analysis showedthat OMV production by strain ΔmlaEΔnlpI was ~30 times that by the wild-type. In addition, to evaluate theprotein secretion capacity of OMVs, green fluorescent protein (GFP) fused with outer membrane protein W(OmpW) was expressed in OMVs. Western blot analysis showed that GFP secretion through OMVs reached
3.3 mg/L in the culture medium of strain ΔmlaEΔnlpI /gfp, 500 times that for the wild-type. Our approach
using OMVs for extracellular protein secretion in E. coli is an entirely new concept compared with existing
secretion systems.
Chromatin-bound CRM1 recruits SET-Nup214 and NPM1c onto HOX clusters causing
aberrant HOX expression in leukemia cells
Masahiro OKA, Sonoko MURA, Mayumi OTANI, Yoichi MIYAMOTO, Jumpei NOGAMI, Kazumitsu
MAEHARA, Akihito HARADA, Taro TACHIBANA, Yoshihiro YONEDA, Yasuyuki OHKAWA
Elife 8:e46667. doi: 10.7554/eLife.46667. (2019)－48－

We previously demonstrated that CRM1, a major nuclear export factor, accumulates at Hox cluster regions torecruit nucleoporin-fusion protein Nup98HoxA9, resulting in robust activation of Hox genes (Oka et al., 2016).
However, whether this phenomenon is general to other leukemogenic proteins remains unknown. Here, weshow that two other leukemogenic proteins, nucleoporin-fusion SET-Nup214 and the NPM1 mutant, NPM1c,which contains a nuclear export signal (NES) at its C-terminus and is one of the most frequent mutations inacute myeloid leukemia, are recruited to the HOX cluster region via chromatin-bound CRM1, leading
to HOX gene activation in human leukemia cells. Furthermore, we demonstrate that this mechanism is highly
sensitive to a CRM1 inhibitor in leukemia cell line. Together, these findings indicate that CRM1 acts as a key
molecule that connects leukemogenic proteins to aberrant HOX gene regulation either via nucleoporin-CRM1
interaction (for SET-Nup214) or NES-CRM1 interaction (for NPM1c).
Detection of Rhizopus-specific antigen in human and murine serum and bronchoalveolar lavage.
Wataru SHIBATA, Mamiko NIKI, Kanako SATO, Hiroki FUJIMOTO, Koichi YAMADA, Watanabe Tetsuya
WATANABE, Miyazaki Yoshitsugu MIYAZAKI, Asai Kazuhisa ASAI, Yoko OBATA, Taro TACHIBANA,
Tomoya KAWAGUCHI, Yukihiro KANEKO, Hiroshi KAKEYA.
Med. Mycol. myaa001. doi: 10.1093/mmy/myaa001. (2020)
Mucormycosis is a deep-seated fungal infection that mainly develops in patients with severe
immunodeficiencies such as those with malignant hematological diseases. Despite poor prognosis, there is no
reliable and minimally invasive diagnostic method-such as serodiagnosis-for making a clinical decision
regarding the condition. As early diagnosis and early treatment improve the prognosis of mucormycosis, thedevelopment of a sensitive early diagnostic method is important. We had previously identified a Rhizopusspecific antigen (RSA) by signal sequence trapping and retrovirus-mediated expression (SST-REX), andevaluated its utility as a diagnostic antigen by constructing a sandwich enzyme-linked immunosorbent assay(ELISA) system to detect serum RSA levels in inoculated mice. In this study, we used the RSA-specific rabbit
monoclonal antibodies generated by novel hybridoma technology to improve the sensitivity of the ELISA
system. We observed an increase in serum and bronchoalveolar lavage fluid (BALF) levels of RSA in mousemodel 1 day after inoculation, suggesting that this newly developed monoclonal antibody-based ELISA system
may be useful for the diagnosis of mucormycosis in the early stages of infection. In addition, we measured
RSA levels in human serum and BALF, and found that serum RSA level was higher in mucormycosis patients(15.1 ng/ml) than that in invasive pulmonary aspergillosis patients (0.53 ng/ml) and the negative control (0.49
ng/ml). Our results suggest that RSA may be a powerful tool for the diagnosis of pulmonary mucormycosis,
and its differentiation from other deep-seated mycoses such as aspergillosis.
PACT/PRKRA and p53 regulate transcriptional activity of DMRT1.
Kazuko FUJITANI, Asako OTOMO, Yuto NAGAYAMA, Taro TACHIBANA, Rika KATO, Yusuke
KAWASHIMA, Yoshiro KODERA, Tomoko KATO, Shuji TAKADA, Kei TAMURA, Nobuhiko
TAKAMATSU, Michihiko ITO.
Genet. Mol. Biol. 43(2):e20190017. doi: 10.1590/1678-4685-GMB-2019-0017. (2020)
The transcription factor DMRT1 (doublesex and mab-3 related transcription factor) has two distinct functions,somatic-cell masculinization and germ-cell development in some vertebrate species, including mouse and theAfrican clawed frog Xenopus laevis. However, its transcriptional regulation remains unclear. We tried to
identify DMRT1-interacting proteins from X. laevis testes by immunoprecipitation with an anti-DMRT1
antibody and MS/MS analysis, and selected three proteins, including PACT/PRKRA (Interferon-inducible
double-stranded RNA dependent protein kinase activator A) derived from testes. Next, we examined the effectsof PACT/PRKRA and/or p53 on the transcriptional activity of DMRT1. In transfected 293T cells,
PACT/PRKRA and p53 significantly enhanced and repressed DMRT1-driven luciferase activity, respectively.
We also observed that the enhanced activity by PACT/PRKRA was strongly attenuated by p53. Moreover, insitu hybridization analysis of Pact/Prkra mRNA in tadpole gonads indicated high expression in female andmale germline stem cells. Taken together, these findings suggest that PACT/PRKRA and p53 might positively
and negatively regulate the activity of DMRT1, respectively, for germline stem cell fate.
Generation of the Rat Monoclonal Antibody Against the Extracellular Domain of Human CD63 by
DNA Immunization.
Liu XU, Kan-Ichiro IHARA, Saori YOSHIMURA, Daijiro KONNO, Akira TACHIBANA, Takeshi
NAKANISHI, Taro TACHIBANA.
Monoclon. Antib. Immunodiagn. Immunother. 39(3):74-76. doi: 10.1089/mab.2020.0007. (2020)
Human cluster of differentiation 63 (hCD63) is one of the tetraspanin receptors that is abundant on the surface－49－

of exosomes. Exosomes are involved in cell-to-cell communication, including from cancer cells to normal
cells. It is very important to detect exosomes as a marker for the diagnosis of various diseases. In this study,
we report the generation and characterization of a monoclonal antibody (mAb) against the extracellular domainof hCD63 using DNA immunization. This mAb, clone 1C8-2B11, exhibits high performance for use inimmunofluorescence and flow cytometry, and it has 10-fold higher affinity than the control antibody that iscommercially available. mAb 1C8-2B11 has great potential to be a tool for research and clinical diagnosis.
Uniform straw-like cell architecture for three-dimensional cell-cell communication assay
Yusaku INUBUSHI, Yoshiki SAKAGUCHI, Akira TACHIBANA
Biosci. Biotechnol. Biochem. Vol.84, pp.1681-1684. (2020)
We fabricated uniform straw-like cell architecture with central lumen using a suture thread within 1 h. The
architecture consisting of cancer cells and mature adipocyte was used for cell-cell communication assay,
although mature adipocyte could not form spontaneous multi-cellular spheroids. Using the system, it ispossible to investigate three-dimensional cell-cell communication as an alternative to animal experiments.
Improvement of a miRNA inhibitor by intracellular selection
Akira TACHIBANA, Aiko YAMAMOTO
Biosci. Biotechnol. Biochem. Vol.84, pp.1451-1454. (2020)
Sequences surrounding the miRNA binding domain of the miRNA inhibitor LidNA were selected
intracellularly. The library was transfected into cells, and then, inhibitors that were associated with argonaute
2 were selected. The potent inhibitors were slowly degraded intracellularly, while the lower-activity inhibitors
were rapidly degraded. A combination of the selected sequences surrounding the miRNA binding domainenhanced miRNA inhibitory activity.
Structural improvement of LidNA: delta-type LidNA is a potent miRNA inhibitor constructed withunmodified DNA
Akira TACHIBANA, Yoshiki KOMEDA, Aiko YAMAMOTO
Biosci. Biotechnol. Biochem. Vol.84, pp. 1168-1175. (2020)
Many miRNA inhibitors have been developed, including chemically modified oligonucleotides, such as 2'-Omethylated RNA and locked nucleic acid (LNA). Unmodified DNA has not yet been reported as a miRNA
inhibitor due to relatively low DNA/miRNA binding affinity. We designed a structured DNA, LidNA, which
was constructed with unmodified DNA, consisting of a complementary sequence to the target miRNA flanked
by two structured DNA regions, such as double-stranded DNA. LidNA inhibited miRNA activity morepotently than 2'-O-methylated RNA or LNA. To optimize LidNA, two double-stranded regions were joined,causing the molecule to assume a delta-like shape, which we termed delta-type LidNA. Delta-type LidNAs
were developed to target endogenous and exogenous miRNAs, and exhibited potent miRNA inhibitory effects
with a duration of at least 10 days. Delta-type LidNA-21, which targeted miR-21, inhibited the growth ofcancer cell lines. This newly developed LidNA could contribute to miRNA studies across multiple fields.
LidNA, a miRNA inhibitor constructed with unmodified DNA, requires an xxxA insertion sequence inmiRNA binding site for its potent inhibitory activity
Akira TACHIBANA, Satoshi SAITO, Yukiko FUJIYAMA, Toshizumi TANABEFEBS Lett. Vol.594, pp.1608-1614. (2020)
The involvement of miRNAs in the pathogenesis of various diseases, including cancer, poses the need fordeveloping miRNA inhibitors. Previously, using unmodified DNA, we designed LidNA, which inhibited
miRNA function more potently than 2'-O-methylated RNA and locked nucleic acid. LidNA consists of acomplementary sequence to miRNA flanked by two structured DNAs. Alterations in the connected sequences
between the complementary region and structured region modestly affect miRNA inhibition activity.
Surprisingly, variations in the mismatched insertion sequence in the center of the complementary sequencesignificantly affect activity. The central insertion sequence xxxA is required for the potent miRNA inhibitory
effects of LidNA. This suggests that both the structure and insertion sequence of LidNA and other miRNA
inhibitors should be considered for maximal miRNA inhibitory activity.
Improved cancer inhibition by miR-143 with a longer passenger strand than natural miR-143
Hiroyuki IDA, Toshizumi TANABE, Akira TACHIBANA
Biochem. Biophys. Res. Commun. Vol.524, pp.810-815. (2020)
We improved miR-143, which inhibits the growth of cancer cells, by the replacement of the passenger strand.

－50－

As a result, new miR-143 variants were developed with a single mismatch at the 4th position from the 3'terminal of the guide strand and an RNA passenger strand with a G-rich flanking DNA region. A reporter geneassay showed that the 80% inhibitory concentration of the new miR-143, long miR-143, was 69 pM, which
was three times lower than that of natural miR-143. Long miR-143 inhibited the growth of two cancer celllines, HeLa-S3 and MIAPaCa-2, more effectively than natural miR-143. This method could be applied to other
miRNA families and should be useful for the development of miRNA drugs.
Uniform spheroid formation on a laboratory-made, low cell attachment surface consisting of a chitin
sheet
Yusaku INUBUSHI, Akira TACHIBANA
Biosci. Biotechnol. Biochem. Vol.84, pp.997-1000. (2020)
We utilized the reaction of chitosan with acetic anhydride to form a chitin gel. This gel was then dried, which
formed a chitin sheet. The procedure was extremely easy for a biologist unfamiliar with materials engineering.
Spheroids derived from HEK293T cells were formed on the chitin sheet, because the spheroids slightly
attached and slowly moved on the chitin sheet.
Fluorescein isothiocyanate and blue light irradiation alter cell-adhesiveness of cross-linked albumin
films for cell patterning
Akira TACHIBANA, Atsuko IIDA, Toshizumi TANABE
Biosci. Biotechnol. Biochem. Vol.84, pp.800-803. (2020)
Cross-linked albumin films, which are non-cell adhesive, were altered to be cell-adhesive by the combinationof varied concentrations of fluorescein isothiocyanate and blue light irradiation. In this system, cell patterning
was developed with two different cell lines by sequential seeding.
Chitin degradation enzyme-responsive system for controlled release of fibroblast growth factor-2
Akira TACHIBANA, Dai YASUMA, Ryo TAKAHASHI, Toshizumi TANABE
J. Biosci. Bioeng. Vol.129, pp.116-120. (2020)
Chitin is widely found in fungal cell walls and arthropod exoskeletons, and is used as a biomedical material.
However, chitin is not water-soluble, restricting its use for controlled release materials. We found that watersoluble chitosan can be acetylated to produce a chitin equivalent, or chitin gel. Chitin gel, produced by mixing
chitosan solution with acetic anhydride, can be degraded by lysozyme and fetal bovine serum, so could provide
an ideal means for controlled release in biological systems. We tested a combination of chitin gel with a chitinbinding domain (CBD) fusion protein as a controlled release system regulated by chitin degradation. A fusion
protein consisting of fibroblast growth factor 2 (FGF-2) fused to CBD bound the chitin gel, and was released
time-dependently rather than as an initial burst during lysozyme degradation, suggesting that this system could
provide a means for controlled drug release in biological systems. Contrastingly, the trinitrophenyl residue(TNP-X) covalently bound to chitin gel, and was released by lysozyme degradation with an initial burst. If
release of CBD-FGF-2 were simply dependent on lysozyme degradation of the chitin gel, the release behaviorof CBD-FGF-2 would be similar to that of TNP-X, with an initial burst. Therefore, we propose that CBDFGF-2 repeats the cycle of binding, release, and re-binding to the chitin gel during degradation. This systemallows for a time-dependent, controlled release of CBD-FGF-2 without an initial burst.

－51－

Urban Engineering
Architecture and Building Engineering
COUPLING EFFECT OF NODAL DEVIATION AND MEMBER IMPERFECTION ON LOADCARRYING CAPACITY OF SINGLE-LAYER RETICULATED SHELL
Huijun LI, Yoshiya TANIGUCHIInternational Journal of Steel Structures (2020) 20(3):919–930
Single-layer reticulated shell is sensitive to imperfections. To clarify the efect of member imperfection, nodal
deviation and their couplings on load-carrying capacity of reticulated shell, the equivalent load method (ELM)
is developed in the present study to establish single-layer reticulated shell with random member imperfection,and its realization procedures in FEM package are well-elaborated. The main conclusions are summarized asfollows: the proposed ELM is of high efciency to form member imperfection in space structures. For reticulatedshell only with member imperfection, the limit load is more or less infuenced by member imperfection. With
the increase of amplitude of member bow imperfection, limit load gradually decreases. Load-carrying capacityof reticulated shell with larger amplitude of bowed member is more sensitive to bending direction of bowed
member than the one with smaller amplitude. Load-carrying capacity of the reticulated shell considered isextremely sensitive to nodal deviation. For reticulated shell with nodal deviation and member imperfection,
the efect of member imperfection on load-carrying capacity is closely related to the magnitude of nodal
deviation. Loadcarrying capacity of shell with smaller nodal deviation is obviously afected by member
imperfection, while not sensitive to member imperfection for reticulated shell with larger one. Member
imperfection can be neglected when nodal deviation is large enough. Load-carrying capacity of reticulatedshell is also infuenced by bending angle of bowed member. On the whole, load-carrying capacity of reticulatedshell with larger amplitude of member imperfection is more sensitive to bending direction than the reticulatedshell with smaller one.
EFFECT OF JOINT STIFFNESS AND SIZE ON STABILITY OF THREE-WAY SINGLE-LAYERCYLINDRICAL RETICULAR SHELL
Huijun LI, Yoshiya TANIGUCHIInternational Journal of Space Structures, 1-18 (2020)
The main aim of the present article is to study the effect of joint stiffness and joint size on load-carrying
capacity of single-layer cylindrical reticular shell. One normalized joint bending stiffness index κb and three
proposed normalized indexes, that is, normalized joint axial stiffness κa, normalized joint shear stiffness κs ,and normalized joint torsional stiffness κt , are used to evaluate the stiffness of joint. Through a large numberof numerical computations, the main conclusions are summarized as follows: κb has a significant effect onlimit load of reticular shell, and this effect has a close relationship to rise-to-span ratio of reticular shell. If κbis larger than 30, the joint can be treated as rigid joint. The relationship between the logarithm of κb and limit
load of reticular shell can be expressed by the logistic formulation. Overall rigidity and load-carrying capacityof reticular shell are greatly influenced by joint axial stiffness. If κa is larger than 30, the effect of joint axial
stiffness on load-carrying capacity of reticular shell is no longer obvious. Otherwise, the load-carrying capacity
will be markedly reduced. The relation between the logarithm of κa and limit load of reticular shell can be
fitted by the Dose–response formulation. The load-carrying capacity of reticular shell is also influenced byjoint torsional stiffness and joint shear stiffness to some extent. The relation between the logarithm of κs andlimit load can be fitted by the Asymptotic formulation. The effect of joint size on overall rigidity and limit loadof reticular shell is evident and cannot be neglected. The limit load gradually decreases with the decrease injoint size, and there is an approximate linear relationship between limit load and joint size.
Cable Arrangement of Ceiling Suspended by Diagonal Cables and its Application to Ceiling with
Conventional Method
Kentaro MATSUSHITA, Susumu YOSHINAKA, Yoshiya TANIGUCHI
Proceedings of the 12th Pacific Structural Conference, Tokyo, Japan, November 9-11, ID5-1-3, pp.1-7 (2019)
In this paper, we use a method like ground structure to determine cable arrangement for a ceiling suspended
by diagonal cables. We also propose an application method for an existed ceiling with conventional method toreinforce using diagonal cables. We analytically study responses using a ceiling with cables and a ceiling withconventional method under earthquake loading. From obtained results, it was found that responses of a ceilings－52－with cables was very small. As the reason, a system of a ceiling added with cables does not have specificnatural periods because of the material nonlinearity of cables. Consequently, a resonance between earthquake
wave and a ceiling does not occur and responses of a ceiling with cables does not depend on the spectrum
characteristics of each earthquake wave. As a result, we concluded that cable was superior to brace as a hanging
material to resist horizontal vibration.
Summer Sleep Quality and Change of Thermal Environment
Noriko UMEMIYA, Kurumi YAMAGATA, Tomohiro KOBAYASHI
Proceedings of the 13rd HVAC World Congress, 3A-247, (2019)
Relation between bedroom thermal environment change and subjective sleep quality and thermal comfort was
surveyed for 63 apartment occupants during midsummer in Osaka. Change of Wet Bulb Globe Temperature(WBGT) of 123 air conditioned and 41 naturally ventilated nights were compared. 1) If bedrooms were air
conditioned, sleep quality was better for smaller change of WBGT since the beginning of sleep and fasterchange of WBGT to constant since the beginning of sleep, 2) If bedrooms were naturally ventilated, a) WBGT
increased since the beginning of sleep and decreased toward the end of sleep for higher sleep quality nights.
On the other hand, WBGT decreased since the beginning of sleep and increased toward the end of the sleep
for lower sleep quality nights. b) WBGT change was smaller for thermally comfortable nights.
Simplified Prediction Method of Vertical Temperature Distribution for Impinging Jet Ventilation
SystemTomohiro KOBAYASHI, Toshiya NISHIUMI, Noriko UMEMIYA
Proceedings of the 13rd HVAC World Congress, 5D-468, (2019)
The impinging jet ventilation (IJV) system is an air-distributing strategy to generate a thermal stratification ina room by supplying the air vertically toward the floor, which provides higher ventilation effectiveness thanmixing ventilation. To date, however, no simplified prediction model of indoor thermal environment for an
impinging jet ventilated room has been established. Therefore, this study aims to propose a simplified
calculation model based on “Block Model”. This paper first presents a parametric study using Computational
Fluid Dynamics (CFD), where total supply airflow rate of a test room is changed as a parameter. The numberof terminal is also changed. Secondly, the paper presents the simplified calculation model of verticaltemperature distribution based on block model that solves heat flow by advection and diffusion. Here, in thisprediction model, the most important parameter is the turbulent thermal diffusivity between two room-space
blocks in vertical direction. The room-space blocks are classified into two types, i.e., lower and upper part ofa room. Based on parametric study using CFD, turbulent thermal diffusivity is arranged for lower and upper
block respectively, and it is finally shown that the vertical temperature distribution from block model wellagrees with CFD result.
Difference of Light Environment Evaluation between Elderly and Young People
Noriko UMEMIYA, Wei QUIAOThe 29th Session of the Commission Internationale de l’Eclairage, pp.745-750, (2019)
Light and Dark conditions were evaluated by elderly people and young people in terms of brightness, glare,
comfort and preference using experiments with Dark-to-Light and Light-to- Dark sequences. Results indicatedthe following: 1) Elderly people were less sensitive in terms of brightness to the difference of illuminancechange order. 2) Elderly people were less sensitive in terms of glare to the difference of illuminance and to thedifference of illuminance change order. 3) The Dark condition was evaluated as less comfortable and lesspreferred than the Light condition in Light-to-Dark experiments for elderly people, although no difference wasfound for young people between the Dark and the Light conditions in Light-to-Dark experiments. 4) The Light
condition in Dark-to-Light experiments had weaker glare by elderly people than by young people. The Dark
condition in Light-to-Dark experiments was evaluated as more comfortable and more preferred by young
people than by elderly people.
Pupil Size Change and Light Evaluation of Elderly People
Noriko UMEMIYA, Yasuha KUREYAMA, Mika TOMITA
Proceedings of the 12th Asia Lighting Conference, pp.510-515, (2019)
This study measured pupil size and forehead illuminance simultaneously for elderly people 65 years or older
and young university students during corridor walking in daily lighting. Subjective evaluation of the lightenvironment in an experimental room was done for dark and light conditions. Brightness, glare, uniformity,
flickering, lighting comfort, lighting preference, and performance were evaluated. Illuminance was 550 lux in－53－the dark condition and 3300 lux in the light condition. For the elderly and young people, pupil size response
to illuminance and the relation of its change to forehead illuminance during walking and subjective lightevaluation to dark and light conditions in the experimental room were compared. The gradient of pupil size toforehead illuminance was used as an index of the response. Results show differences in gradients between
elderly and young people in lighting preference evaluation of the dark condition and in performance evaluationof the light condition.
A Comparison between Elderly People and Young People in Factors Related to Gazing Characteristics
during Walking in Corridors
Mika TOMITA, Noriko UMEMIYA, Yasuha KUREYAMA,
Proceedings of the 12th Asia Lighting Conference, pp.193-200, (2019)
By measuring gazing points of elderly people (65–91) and young people (21–25) as they walked down
corridors, this study examined gazing characteristics and their mutual relations, along with physical strengthand two-step size. Results clarified the following five points. 1) Among these participants, 64.1% of elderly
people and 21.4% of young people had equal to or less than 1.3 two-step size. People with equal to or less than
1.3 two-step size have a higher probability of falling. 2) The frequency distribution of gazing points revealed
four groups: G1) 1 area concentration, G2) 2 area concentration, G3) 3 or 4 area concentration, and G4) morethan 5 area distribution. 3) The two-step size was worst in G2 and greatest in G3 for elderly people. Therefore,
people in G2 tend to fall, but those in G3 do not. Age is unrelated to these results. 4) Gazing characteristics areunrelated to the ease of falling for young people. 5) In G2 of elderly people, someone who is more impervious
to glare has a smaller two-step size.
Relation between School Building Configuration and Heat Mitigation Effects of Lawns in Urban
Regions
Noriko UMEMIYA, Takeshi KISHIMOTO, Tomohiro KOBAYASHI
Proceedings of the 16th International Building Performance and Simulation Association Conference, p.99104, (2019)
Using CFD simulation, this study compared heat mitigation effects of partial turf planting in school yards andof overall turf planting. Typical school lots and surrounding buildings were modelled according to actual
conditions. Temperature contour lines and air flow vectors on school yards showed that heat mitigation effects
are dependent on wind speed and direction. The wet bulb globe temperatures were evaluated and compared.
Turf planting in western parts of the school yards was most effective. Heat mitigation at leeward wind areas
was slight.

－54－

Urban Design and Engineering
Relationship Between Splashing and Wave Deformation around a Circular cylinder in Front of Vertical
Wall
Takehito KAMIKAWA, Takaaki SHIGEMATSU
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), Vol. 75, Issue 2, I_1-I_6 (2019)(in Japanese).
Most of pile-supported piers that have been used in port and harbor in japan faced to the sever deterioration ofslat damage. The purpose of this study is to investigate the conditions of splash occurrence by wave under mild
weather in front of the pile-supported pier by carrying out laboratory experiment and numerical calculation.
According to the experiment, it is found that there are two patterns of splash occurrence. One of them is thatsplash occurs on the vertical wall and the other is that at the convergence point of surface waves surrounding
the circular cylinder. The calculation results show the potential which OpenFOAM can simulate the wave
refraction and convergence and can predict the variation of wave convergence location due to the conditionsof waves and pile-supported pier.
On the Effect of Aspect Ration of Component Member on the Flow Through Porous Media
Yuya WATANABE, Sota NAKAJO, and Takaaki SHIGEMATSU
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), Vol. 75, Isuue 2, I_943-I_948(2019) (in Japanese).
Various models of the porous media flow have been proposed to quantitatively examine the heat and masstransfer inside and around porous media, and the stability of the porous structures. In most studies, porous
media components are approximated by spheres. However, natural gravel layers or artificial wave dissipating
structures are composed by ellipsoids. Actually, the flow passing through an ellipsoidal porous media is
unknown. In this study, we performed numerical simulation to study the microscopic flow in the porous media
composed by ellipsoids using an immersed boundary method. Simulation results show that macroscopic
pressure drop and fluid force acting on the each component of porous media are influenced by the aspect ratioof ellipsoid.
Practical Formula for Effective Height of Impermeable Hanging Curtain in Steady Water Flow
Masahide TAKEDA, Takaaki SHIGEMATSU, Yoshinosuke KURAHARA, Chisato HARA, Yamato
NISHIYAMA
Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), Vol. 75, Issue 2, I_409-I_414 (2019)(in Japanese).
This study aims to propose a new prediction formula of the effective height of a hanging curtain in steadywater flow. According to the hydraulic experiments and numerical calculations, the more practical calculation
formula of the effective curtain height was obtained using the ratio of dynamic pressure and weight and theratio of the effective curtain height to the curtain length. Our formula is characterized in that the experimental
coefficient is without user specification, and the weight is included in the formula, and the parameter using theratio of the initial curtain height to the water depth is used.
Development of Global Stochastic Tropical Cyclone Model by using large ensemble GCM simulation
data(d4PDF)
Jinji UMEDA, Sota NAKAJO, Nobuhito MORI
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), Vol. 75, Issue 2, I_1195-I_1200(2019) (in Japanese).
A global stochastic tropical cyclone model (GSTM) considering time series correlation of tropical cyclone
properties has been developed by using large ensemble GCM simulation data (d4PDF). The bias of d4PDF has
been corrected by using the information of the average and the standard deviation of tropical cyclone properties
comparing with that of IBTrACS. AS a result, we could get accurate correction results at each 3 degree grid.
The improvement of the reproducibility of the frequency has been observed at many area by using the joint
probability distribution functions (JPDF) of GSTM approximated from the corrected d4PDF data. Especially,
this improvement was significant in the area that the tropical cyclone data is insufficient. The simulation results
show the variation of the change rate of future tropical cyclone frequency around Japan and the intensificationof tropical cyclone depending on the SST scenario.

－55－

Pesudo Prediction Experiments of Storm Surge and Waves in 2018 Typhoon Jebi by High Resolution
Weather Prediction and Coupled Surge-Wave Model
Nobuhito MORI, Tetsuya TAKEMI, Sooyoul KIM, Yoko SHIBUTANI, Tomohiro YASUDA, Sota NAKAJO,
Junichi NINOMIYA, Tomoya SHIMURA
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), Vol. 75, Issue 2, I_283-I_288(2019)(in Japanese)
Using high-resolution numerical weather prediction model and coupled storm surges and waves, we conductedpseudo-prediction experiments on the maximum wind speed, maximum storm surge height, and maximum
wave height for 2018 Typhoon Jebi. The central pressure and maximum wind speed of the typhoon become
more accurate as the forecasting time length becomes shorter. The minimum central pressure and maximum
wind speed of typhoon at landfall are reasonably estimated 3 days and 2.5 days before the landfall, respectively.
In the 4 days length prediction, the peak appearance time of the event is estimated about 12 hours later, but theaccuracy is increased as forecast length becomes shorter. The difference of the storm surge height between theprediction and hindcast is less than 0.5 m at the maximum. The reliable prediction of storm surge can beobtained from 2 days ago of landfall, quantitatively.
Hindcast of Storm Surge and Wave by Typhoon Jebi (2018) Using a Parametric Wind and Pressure
Model and WRF
Sooyoul KIM, Nobuhito MORI, Tetsuya TAKEMI, Yoko SHIBUTANI, Tomohiro YASUDA, Sota NAKAJO,
Tomoya SHIMURA, Junichi NINOMIYAJournal of Japan Society of Civil Engineers, Ser. B3 (Coastal Engineering), Vol. 75, Issue 2, (2019) , I_277I_282 (in Japanese).
This study aims to propose a new prediction formula of the effective height of a hanging curtain in steadywater flow. According to the hydraulic experiments and numerical calculations, the more practical calculation
formula of the effective curtain height was obtained using the ratio of dynamic pressure and weight and theratio of the effective curtain height to the curtain length. Our formula is characterized in that the experimental
coefficient is without user specification, and the weight is included in the formula, and the parameter using theratio of the initial curtain height to the water depth is used.
Basic Study on the Estimation of Potential of Tropical Cyclone and Storm Surge around Ishigakijima
IslandSota NAKAJO, Hibiku HANAMOTO, Sooyoul KIM
Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), Vol. 75, Issue 2, I_67-I_72 (2019)(in Japanese).
The reproducibility of stochastic tropical cyclone model in Ishigaki-jima Island has been examined and showed
the good performance. The reproduced typhoon intensity and the storm surge for 5000 years have been
estimated from results of the combined stochastic and empirical estimation models. In this area, the tropical
cyclones translate toward the north and north-east is severe to the storm surge. However, the substantial riskof the storm surge caused by the tropical cyclone translate toward the north-west is relatively higher.
2018 Typhoon Jebi Post-Event Survey of Coastal Damage in the Kansai Region, Japan
N. MORI, T. YASUDA, T. ARIKAWA, T. KATAOKA, S. NAKAJO, K. SUZUKI, Y. YAMANAKA, A. WEBBCoastal Engineering Journal, Vol. 61, No. 3, 278 – 294 (2019)
Typhoon Jebi in 2018 caused severe damage along areas of Osaka Bay, Japan. After the storm, a Japan Societyof Civil Engineers (JSCE) coastal survey group surveyed the coastal impacts and recorded watermarks inside
Osaka Bay and along the Pacific. The maximum storm tide recorded by a tide gauge was 3.29 m at the Osaka
Tide Station, which is a historical high for Osaka Bay. Coastal flooding consisted of both storm surge and wave
run-up in almost all locations, with flooding exceeding 5 m and 12 m in elevation from mean sea level in the
inner parts of Osaka Bay and along the Pacific coast, respectively. Coastal damage was severe in areas locatedoutside of coastal barriers, such as ports and harbors, while residential areas were mainly well protected andspared due to coastal protection systems. In addition, some inland flooding occurred in the Kobe-Ashiya
regions due to the storm surge propagating up several small rivers. This survey report summarizes the findingsof the post-event survey by JSCE and analyzes the relation between maximum water level and resulting
damage.

－56－

Low-frequency Catastrophic Coastal Disaster Events around Tonga: Survey of Coastal Boulder
Distribution on Tongatapu Island and Analysis Using Stochastic Modelling of Tropical Cyclones
S. NAKAJO, J. NINOMIYA
Proceedings of the 29th International Ocean and Polar Engineering Conference, (2019)
A field survey of the coastal boulder distribution on Tongatapu Island was performed to obtain evidence of theold coastal disaster. The development potential of the tropical cyclone around this area was estimated using
the stochastic tropical cyclone model. Thirty-eight boulder datasets, including boulder information not reported
in previous studies were collected. Information concerning historical tropical cyclone data is very limited forthe assessment of the low-frequency disaster event. A stochastic model was applied to generate a 25,000-year
simulation of the tropical cyclone. If the Haiyan-like tropical cyclone attacks the Tongatapu Island, mostboulders would be transported by high waves. According to the result of the frequency analysis of this study,
this is not an entirely unlikely situation. The strong tropical cyclone often transverses to the Southeast aroundthe Tongatapu Island. These characteristics are in rough agreement with the fact that the boulder distribution
aggregates to the northwest coast of the Tongatapu.
Characteristics of Air-water CO2 Exchange at the Yamato River Mouth by Continuous Water Quality
Monitoring
Toru ENDO, Hironobu IMAYOSHI and Noriko HARADA
Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), Vol. 75, No. 2, I_1165-I_1170(2019) (in Japanese).
Water quality monitoring surveys were carried out for every season at the mouth of the Yamato river in order
to examine the air-water CO2 exchange characteristics in the urban estuarine area. In addition, we obtained aregression equation between the electrical conductivity (EC) and the total alkalinity (TA) based on therelationship between EC and TA of the water sampled at some points of Yamato river in order to estimate theTA required for calculation of the partial pressure of CO2 in water (pCO2) from the monitoring data of EC.
The pCO2w had large daily fluctuations in summer and fall, but the pCO2w had small values and small daily
fluctuations in winter. As a result of multiple regression analysis of pCO2w and the observation items, the airwater CO2 exchange depended on the change in salinity due to the tidal change and the change in pH due tothe photosynthesis and the respiration. The averaged air-water CO2 flux was 7.9 ± 0.6 CO2/m2/hr in spring,
2.90 ± 0.7 CO2/m2/hr in summer, 16.2 ± 1.3 CO2/m2/hr in fall, -4.2 ± 0.5 CO2/m2/hr in winter, and the Yamato
river estuarine area acted net CO2 sources except in winter.
Air-sea CO2 Exchange and dissolved Inorganic Carbon in an Inner Part of Osaka Bay, Japan
Toru ENDO, Junpei SHIMANO, Noriko HARADA, Daiki SAKAI, Ryuichi FUJIWARA
Proceedings of the 10th International Conference on Asian and Pacific Coasts, 1073-1079. (2019)
The carbon captured by coastal oceans and ecosystems called "blue carbon" is attracting attention to reducegreenhouse gas. Recently, field surveys on air-sea CO2 exchange have been conducted in various coastal seas
to reveal the blue carbon function. In this study, we investigated the vertical distribution of the dissolved
inorganic carbon (DIC) system in the inner part of Osaka Bay to reveal the air-sea CO2 exchange characteristics
in port and harbor area. Field surveys were conducted on a vertical seawall in Naruo-hama of Osaka Bay, Japan,
during 12 months from November 2014 to October 2015 and during summer from August to September 2016.
The vertical distributions of DIC and pH were measured on site, and the CO2 partial pressure in water (pCO2w)
was calculated based on carbon acid equilibrium. Water temperature, salinity and DO were also measured to
examine the relationships the vertical distribution of DIC system and water mass structure. Furthermore, theair-sea CO2 flux (FCO2) was estimated to examine the characteristics of the air-sea CO2 exchange. DIC ranged
from 787 to 2,111 μmol kg-1, with seasonal and vertical change. DIC in the bottom layer increased during highwater temperature period due to CO2 production by respiration and decomposition, and DIC accumulated alongwith formation density stratification. The correlation between DIC and pCO2w in surface layer was smaller
than that in bottom layer because surface pCO2w fluctuated due to inflow of river water or seawater mixing.
This study area acts as CO2 sinks under calm conditions (FCO2 = -3.4 mmol-C m-2 d-1), however the site acts
CO2 sources (1) when density stratification was relaxed (FCO2 = 2.1 mmol-C m-2 d-1); (2) when water was
mixed by disturbance such as typhoon (FCO2 = 1.3 mmol-C m-2 d-1); and (3) when it rained (FCO2 = 15.5 mmolC m-2 d-1).

－57－

Study on the Functions of Groins in Incubating Waterside Spaces: A Proposal for Planning and
Maintenance to Generate Diversity of Waterside
Yasumasa FUKUSHIMA, Takashi UCHIDA
Society of Environmental Conservation engineering, Journal of Environmental Conservation engineering,
Vol.48, No.4, pp.34-42, (2019) (in Japanese)
River management in recent years involves measures for waterside management, emphasizing the environment
and its beneficial use as well as flood control and irrigation. Taking part in the trend of waterside management,
this study, which focuses on the first author’s engagement of planning so far， (1) evaluates the functions ofgroins in incubating waterside spaces concerning the aspects of environment, utilization, and management and(2) proposes specific measures for problems and points of attention regarding structural types, scales, andconstituent materials in the planning phase to apply the groin function, based on our knowledge obtained by
the process of planning, project implementation and deterioration due to aging, together with the result of ourhearing survey towards the users.
Sightseeing Verbal Maps for Visually Impaired by Using Virtual Reality System Specialized in Sound
Yuta YANAGAWA, Takashi UCHIDA, Hiroko MATSUMOTO
Japan Society of Civil Engineers，Proceedings of Infrastructure Planning, No. 59，pp.109_1-6 (2019) (inJapanese)
Visually impaired people can walk on the street using a voice AR application that replaces visual in-formation
and auditory information. However, there are always some risks. It is difficult for visually im-paired people touse it safely in unfamiliar areas, and to understand voice guidance correctly.
This research tries a virtual reality system that reproduces sound of the city using in sound of virtual reality inindoor space and uses the voice AR application for the visually impaired people. We will im-prove therecording method and reproduction method of environmental sound and aim for the development to"sightseeing verbal maps."
Current and Future Situations of Automatic Driving in China and Japan
HAINAER BULATAI, Takashi UCHIDA
Osaka City University, Memoirs of the Faculty of Engineering, Vol. 60, pp.1-11 (2019)
Conducting social acceptance surveys in Japan and China requires understanding of the current situation of
automatic driving technology and the difficulties posed by transmission of future technologies. To analyze thestatus quo and to assess differences in automatic driving in China and Japan, this research begins withassessment of the three basic technologies of automatic driving. Then identification technology, programming
technology, and control technology are analyzed by comparing the equipment of intelligent auxiliary systems
of companies in China, Japan, and the United States. By analyzing the current state of development, thecompany plans can indicate the future of automatic driving.
Case Study on the Daily Use of Two-rider Bicycles for Persons with Reduced Mobility by Welfare Service
Providers
Takuya KONISHI, Nagahiro YOSHIDA
Japan Society of Civil Engineers，Journal of Japan Society of Civil Engineers, Ser. D3 (Infrastructure Planningand Management), Vol. 75, Issue 5, pp. I_1197-I_1203 (2019) (in Japanese)
It is demanded to realize the society anyone can travel freely, and the two-rider bicycle might be a potential,
practical means of transportation for persons with reduced mobility (PRM). The purpose of this study is tounderstand the latent opportunities for use of two-rider bicycles by PRM and welfare service providers fromthe questionnaire and hearing survey, and to understand the influences of the daily use of two-rider bicycles
by welfare service providers from the fact-finding case survey. The results confirmed that there were latent
opportunities and some influences by PRM and welfare service providers, it might lead to promotion of using
two-rider bicycle for PRM and welfare service providers.
A Study on the Effect of Motorcycle Traffic Safety Workshop for High School and University Students
in Phnom Penh, Cambodia
Toshiki KOYANAGI, Nagahiro YOSHIDA, Yuto KITAMURA
Transportation Research Board (TRB) 98th Annual Meeting, Poster No. 19-01976, 13 pages (2019)
In Cambodia, motorcycle use has spread rapidly in recent years, and serious accidents involving motorcycles
have increased. In particular, many young motorcyclists have been involved in traffic accidents, and various－58－issues in traffic safety are remained. To understand the current situations related to these issues in Phnom Penh,
Cambodia, a video observation survey on driving situations of motorcycle users in high school and university
were conducted. Based on the results, a traffic safety workshop was held to improve their risk perception ability
and basic riding skills. In this study, a statistical analysis was conducted to compare driving behavior on arterial
roads before and after the workshop. The results showed that some behavioral changes are considered to beeffects of the traffic safety workshop, and especially, driving skill learning is thought to have had an effect on
aggressive behavior and the risk perception training on defensive behavior.
Changes in Subjective and Objective Comfort for Pedestrians and Cyclists After Road-Space
Reallocation: A Case Study of Midosuji, Osaka
Haruka KAWACHI, Pola, BERENT, Nagahiro YOSHIDA, Taku FUJIYAMA
The 13th International Conference of the Eastern Asia Society for Transportation Studies (EASTS), 10 pages(2019)In Japan, a road space reallocation project on Midosuji, the main street in Osaka, started in 2017 based on theconcept of human-centered urban space. The project has widened the space for pedestrians and cyclists andnarrowed the carriageways. This is an effort to ensure the comfort of pedestrians and cyclists. The Level ofService (LOS) concept is often used to evaluate user comfort. However, there is a possibility that the LOS may
not be able to fully provide comfort in a mixed space of both pedestrians and cyclists. This study investigated
the actual situations of pedestrians and cyclists on Midosuji in order to widen the street for them. A
questionnaire survey (subjective indicator) and a video survey (objective indicator) were compared based on
three sections of the road: an undeveloped section, a developed section without rest spaces, and a developed
section with rest spaces.
A Review of the Contents of Bicycle Use Promotion Plans in Local Governments
Katsumasa TATSUNO, Nagahiro YOSHIDA
Japan Society of Civil Engineers，Proceedings of Infrastructure Planning, No. 60，4 pages (2019) (in Japanese)
In June 2018, Ministry of Land, Infrastructure, Transport and Tourism (MLIT) formulated “Bicycle Utilization
Promotion Plan” with the aim of promoting the use of bicycles and increasing public interests by reducing thedegree of dependence on automobiles. In addition, it was obliged for prefectures nationwide to formulate“Regional Bicycle Utilization Promotion Plan” according to the local situation, and it is gradually being
formulated. At present, the contents of the Regional Bicycle Utilization Promotion Plan are entrusted to local
governments. Therefore, in this study, we decided to focus on the features and differences of the plan contents
in the country, prefectures, and municipalities, and the relevance of each other in promoting the use of bicycles.
As a result, prefectures had a higher compliance rate than municipalities, and the compliance rate was lower
for municipalities, but there were doing a lot of regional specific initiatives that differed from the measures of
MLIT.
An Evaluation of Bicycle Class for Preschool Children using Balance Bicycles
Nagahiro YOSHIDA
Japan Society of Civil Engineers，Proceedings of Infrastructure Planning, No. 60，4 pages (2019) (in Japanese)
Inspired by the Danish cycle education for children, Cycling Games events with children of 3-6 years onbalance bicycles have been organized in several cities of Japan including Osaka, Kyoto, Kanazawa, Shizuoka,
and Tokyo since 2016 in collaboration with Urban Cycle Planning-Cycling Embassy of Denmark. The Danish
Cycling Games (DCGs) promoted by the Danish Cyclists’ Federation throughout Danish kindergartens andschools are based on the method “learning by playing”, these games are considered to develop the children’s
motor skills and a sense of safety and make cycling fun. To recognize cycling classes as a part of education forchildren in Japan, it was necessary to clarify the following: suitability for each age group, effects ofconceptualizing such a program, and differences from other similar programs. Therefore, we conducted aquestionnaire survey for teachers from 74 institutions: 15 city-supported kindergartens and nurseries in Kyoto
City and 59 city-supported kindergartens and nurseries in Shizuoka City after performing DCGs at each
institution in 2018.
Evaluation of Road Space Reallocation Arrangement and Rest Space Installation for Pedestrians andCyclists Using the Level of Service Concept on Midosuji Boulevard
Haruka KAWACHI, Nagahiro YOSHIDA, Pola BERENT
Osaka City University, Memoirs of the Faculty of Engineering, Vol. 60, pp.13-18 (2019)－59－

The road space reallocation project on Osaka's main street, Midosuji, started in 2017 to realize the concept ofhuman-centered urban spaces in response to the change of social trends and conditions. The pilot project has
been undertaken to increase spaces for pedestrians and cyclists. While the "Level of Service" concept was
widely employed to evaluate user comfort issues in the transportation field, it is unknown whether it could
apply to these space differences and evaluate the reallocation effect correctly. In this study, we show theelements that are not expressed by the Level of Service and are directed towards a more realistic comfort
assessment; for example, rest spaces in road designs, and the expected and necessary speed to avoid worsening
traffic flow.
Vital Reactions as a Measure of Stress Levels in Bicycle Riders According to Degree of Task
Katsumasa TATSUNO, Nagahiro YOSHIDA
Osaka City University, Memoirs of the Faculty of Engineering, Vol. 60, pp.19-25 (2019)
In this study, the amount of stress felt by bicycle riders is analyzed to obtain a method for measuring therelationship between the stress factors of the rider and the rider reaction to the environment, particularly whileriding in bike lanes. Several vital reaction indices are used in a variety of traffic environments with differing
stress factors. This study examines individual differences to include the level of riding experience andcomplexity of bicycling tasks to better explicitly consider the differences in experience related to stress andthe complexity of riding in each environment. We also compare the differences in the vital reaction by the
influence of individual based on biking experience and complexity of biking tasks. Results indicated thatduring a ride in the bike lanes, multitasking induced higher values in all indices of vital reactions, comparedwith the responses recorded under single-task conditions. It was also found that the vital reactions in subjects
who rode their bikes daily tended to be higher under all biking conditions compared with the reactions of those
who rode bikes only occasionally.
Vital Reactions as a Measure of Stress Levels in Bicycle Riders According to Task Complexity
Katsumasa TATSUNO, Nagahiro YOSHIDAThe 8th International Cycling Safety Conference 2019, Brisbane, Australia, 18-20 November 2019.
There are various types of bicycle infrastructure, including separated and shared paths on sidewalks androadways alongside other transportation modes. Although each type of bicycle path requires different skills
and confidence from cyclists, interactions between user response and path conditions have not been captured
well. Previous studies have shown that safety, stress, and comfort levels of cyclists affect route choice
behaviours. In terms of stress response, researchers have developed evaluations of road conditions bymeasuring vital reactions using heart rate interval (RRI), Galvanic skin response (GSR),
Electroencephalography (EEG), and Electromyography (EMG). While riding a bicycle in various conditions
affects user response through vital reactions, few studies have considered the comprehensive relationshipbetween stress response and the task intensity, as cycling requires physical activity under complex task
conditions. Therefore, in order to obtain some basic insights on vital reactions associated with road conditions
during bicycle use, an experimental observation of vital reactions using RRI, EMG, and GSR in two different
designated courses that required different riding tasks considering individual riding experience was conducted.
Subjects were five students with different frequencies of bicycle usage on a daily basis. Results indicated thatvital reactions while riding on the paths requiring multitasking, such as movement among other bicycle users
and tilting the vehicle during curved driving, showed an increase on all indices compared to the reactions undersingle-task conditions. In addition, it was found that the vital reactions in daily users tended to be larger under
any driving conditions compared to the reactions of occasional users. With respect to the next step, additional
observations on different roads under heavy traffic conditions will be measured, followed by an analysis of theinterrelationship be-tween riding situations associated with traffic conditions and vital reactions.
Total Organic Carbon in the Leachate from Highly Reactive Slaked Lime and Municipal Solid Waste
Incineration Fly Ash
Satoshi MIZUTANI, Katsunori MATOZAKI, Yoshinori KANJO
Proceedings of The 10th Forum on Studies of Environmental and Public Health Issues in Asian Mega-cities(EPAM 2019), December 11−15, 2019, Gifu, Japan, (2019)
High levels of total organic carbon (TOC) are often detected in leachate from municipal solid waste
incineration (MSWI) fly ash in Japan. In this study, the Characteristic and influences of highly reactive slaked
lime for organic load in the leachate from MSWI fly ash are discussed. First, TOC in the leachates from 13
kinds of MSWI fly ash in Japan was measured. Ignition loss (IL) of each type of fly ash was also measured to－60－

determine the content of organic matter. There was no relationship between TOC and IL. Higher TOC levels
were detected in leachate only from fly ash from incinerators with dry-acid gas treatment systems (slaked lime
injection system). This suggests that the TOC of the leachate from the abovementioned fly ash was derived
from slaked lime for the neutralization of acid gas. Subsequently, 18 kinds of commercially available highly
reactive slaked lime were obtained and the TOC of their solution was measured. The leached TOC from unit
weight of the slaked lime was in the range of 0.04–6.56 mg/g. In contrast, normal industrial slaked lime andCa(OH)2 reagent do not contain organic materials. Generally, there was a positive correlation between COD
and TOC in slaked lime. TOC showed 60–80% of CODMn values. Furthermore, two kinds of COD, that is
CODMn and CODCr, in the solution of each highly reactive slaked lime are measured, and the chemicaldegradability of the materials is studied. The ratio of difference between CODCr and CODMn in CODCr was
23.5–48.1% and it suggests that approximately a quarter to a half of leached TOC from highly reactive slaked
lime were organic carbon with low chemical degradability.
Evaluation of Relationship between Businesses’ Handled Amount and Released / Transferred Amountof Chemical Substances Aimed for Predicting Chemical Pollution due to Earthquake Disaster by Using
PRTR Data
Ryusuke SUGIURA, Satoshi MIZUTANI, Satoshi NAKAMURA, Yusuke TAWA, Yoshinori KANJO
Proceedings of The 10th Forum on Studies of Environmental and Public Health Issues in Asian Mega-cities(EPAM 2019), December 11−15, 2019, Gifu, Japan, (2019)
It is important to estimate the degree of waste that may result from natural disasters such as large earthquakes
and tsunamis to effectively plan for disaster waste management. More specifically, it is especially crucial toestimate the quantity of hazardous chemical waste that a disaster may yield to plan environmental protection
measures and proper waste treatment. To estimate such a phenomenon, it is necessary to first determine theamount of chemical substance present in a specific area. Although information about the release and transfer
of chemicals is published under the pollutant release and transfer register (PRTR) system, PRTR data does notmean existing amount of chemicals. Notably, while information about the release and transfer of chemicals ispublished nationwide under the PRTR system, that on the handling of chemicals is only available at the limited
number of local governments level. This study estimates for Osaka Prefecture by calculating the ratio between
the amount of chemical substances released and transferred and the amount of chemical substances handled,
and discusses the differences by fiscal year and by regions (i.e., local government). The difference between theyears proved smaller than that between local governments. This paper argues that the larger difference between
regions is due to the differences in the types of industries or industrial processes in each area.
Relationship between Melting Temperatures and Inorganic Compositions of Sewage Sludge
Yoshinori KANJO, Yuuki MATSUZAKI, Takeki SASAGAWA, Naoya KOUDA, Satoshi MIZUTANIProceedings of The 10th Forum on Studies of Environmental and Public Health Issues in Asian Mega-cities(EPAM 2019), December 11−15, 2019, Gifu, Japan, (2019)
In order to decrease the emission amount of N2O gas, which is one of the typical greenhouse gases, from these
combustors for sewage sludge, more than two million tons (dry weight) of sewage sludge generated fromdomestic wastewater in Japan is combusted over 850 Celsius degrees. But high temperature leads to theformation and accumulation of ash deposits on heat transfer surfaces and makes clogging in heat transfer
equipment. This phenomenon is called fouling, and leads to break down of the combustion systems. In thisstudy, we measured the melting temperatures with differential thermal analyzer (DTA) and inorganic
compositions of sewage sludge discharged from two sewage treatment plants for 18 months. The results showthat the melting temperatures of sewage sludge tend to decrease in dry season including with winter season.
Especially for January and February in 2018, the melting temperatures of sewage sludge decreased around 800
Celsius degrees, which is lower than the combustion temperature. From the viewpoint of temperature, it was
supposed that a portion of the sewage sludge ash in this period melted and formed ash deposits at the surfaceof combustor and heat transfer equipment. Judging from the results of relationship between melting
temperature and inorganic contents of sewage sludge, the melting temperatures increased with the contents ofaluminum and iron, and decreased with the contents of phosphorus and potassium. The silica contents did notaffect the melting temperature but decreased the peak area obtained with DTA, which is proportional to theamount of melting materials. Therefore, it will be better to use inorganic flocculation agents such as polyaluminum chloride or poly-ferric sulfate in dewatering process prior to combustors to prevent the formation ofash deposits.

－61－Comparison and Evaluation of Adsorption Properties of Biochars for Hydrophilic Organic Chemicals
Hiroki UENO, Satoshi ENDO, Yoshinori KANJO
Proceedings of The 10th Forum on Studies of Environmental and Public Health Issues in Asian Mega-cities(EPAM 2019), December 11−15, 2019, Gifu, Japan, (2019)
In order to evaluate the contaminated water purification ability of biochar, which is various organic carbides,
adsorption experiments were performed using linear alkylbenzene sulfonate (LAS). 9 kinds of biochar (1 typefrom natural wood, 2 types from sawdust, 2 types from bamboo, 1 type from sewage sludge and 1 type fromchicken manure) and 2 kinds of activated carbons (One each from wood and sawdust) were used as adsorbents.
The adsorption coefficient and surface area of each adsorbent were measured, and adsorption isotherms werecreated and compared. A positive correlation was observed between the adsorption coefficient and the surface
area regardless of the raw material and carbonization temperatures. Moreover, the common logarithm of theadsorption coefficient of Sawdust Charcoal produced at a carbonization temperature of 800℃ was about 5.6,
almost the same as that of activated carbon. As the LAS concentration increased, the biochar adsorptivity
decreased within the experimental range, but the adsorptivity of activated carbon did not decrease. When the
pH of the suspension solutions of adsorbents was measured, the pH was alkaline in all suspension solutions.
Therefore, assuming the actual environment, the adsorption experiment was conducted by adjusting the pH of
the suspension to around neutral. As a result, around neutral pH, the adsorption coefficient of activated carbon
is about 2.4 times that at alkaline pH. However, in the case of Sawdust Charcoal, the adsorption coefficient at
neutral pH was about 1/10. The adsorptivity of Sawdust Charcoal decreased at high concentrations of LAS or
under neutral pH. The upper limit of environmental standards for LAS aquatic life conservation was 0.05 mg/L
in Japan, and Sawdust Charcoal seemed to be useful in the actual environment.
Determination of Effective Diffusion Coefficient of Sodium in Municipal Solid Waste Incineration
Bottom Ash by Diffusion Tube Test
Satoshi MIZUTANI, Ryotaro NAOI, Saki AIHARA, Koji ITO, Yoshinori YABUKI, Yoshinori KANJO
Proceedings of the 3R International Scientific Conference on Material Cycles and Waste Management(3RINCs2020), March, Tsukuba, Japan (2020)
In order to evaluate the transport of harmful substances in landfills, we attempted to measure the diffusion
coefficient in incinerated ash. The municipal waste incineration bottom ash to which sodium chloride wasadded was filled into a polyethylene tube, allowed to stand for 5 days, and then sliced thinly to analyze thesodium concentration. Based on the results of the experiment, a concentration profile was drawn, and the
diffusion coefficient obtained by an approximation method to the theoretical equation of the diffusion
phenomenon was pDe = 9.13. Since the diffusion coefficient was considered to be a reasonable value, thisestimation method was considered to be useful.
Visualization of Chemical Substances Information by GIS Aimed for Predicting the ChemicallyContaminated Wastes Generation due to Great Earthquake Disaster
Ryusuke SUGIURA, Satoshi MIZUTANI, Yusuke TAWA, Satoshi NAKAMURA, Yoshinori YABUKI,
Kazushi NORO, Yoshinori KANJO
Proceedings of the 3R International Scientific Conference on Material Cycles and Waste Management(3RINCs2020), March, Tsukuba, Japan (2020)
When a large-scale earthquake or tsunami occurs, hazardous chemical substances used in businessestablishments may leak, pollute the surrounding environment, and generate the chemically contaminatedwastes. Therefore, estimating the location of chemical substances, the amount that can be leaked, and theamount of generated the chemically contaminated wastes is important in formulating a disaster waste disposal
plan. In this study, the information on chemical substance amounts and handling place published in a chemical
substances management system, pollutant release and transfer register (PRTR) system, was visualized using
GIS. Chemical substances subject to the PRTR system were classified according to their state of ordinary
temperature and pressure, and physical/chemical properties (specific gravity, vapor pressure, and solubility),
assuming how the chemically contaminated wastes would be generated by earthquakes and tsunamis.
Furthermore, when the amounts of released/transferred for each classified substance were shown on a map,the distribution was different from the map in which those amounts for all substances were plotted. From this,the necessity to grasp information based on the characteristics of chemical substances was confirmed.
Leaching Behavior of Lead and Cadmium from Municipal Solid Waste Incinerator Fly Ash Stabilizedby Chemical Agents 24 Years Ago－62－

Shota MASAKI, Satoshi MIZUTANI, Yoshinori KANJO, Shin-ichi SAKAI
Proceedings of the 3R International Scientific Conference on Material Cycles and Waste Management(3RINCs2020), March, Tsukuba, Japan (2020)
To confirm the long-term metal-stabilizing effects of chemical agents used 24 years ago, a Japanese standard
leaching test (JLT-13) and pH-dependent test were conducted on municipal solid waste incinerator fly ash. The
results were compared with previous test results. Based on the JLT-13 results, the pH decreased in nearly all
samples. For some materials, the leached cadmium concentration increased. From the results of the pHdependent test, the rough shape of the lead and cadmium pH-dependent curves were similar to those of pastsamples. It was confirmed that the stabilizing effect was generally maintained for 24 years. Particularly for
one fly ash sample stabilized with an inorganic chemical agent, it was confirmed that lead mineralization had
progressed and the stability under acidic conditions had increased. However, for the stabilized samples with acertain chelating agent, the lead and cadmium leachate concentrations increased under acidic conditions.

－63－

List of Presentations
atInternational Conferences

Presenters are underlined in the list of authors.
Undergraduate or graduate students of the Faculty of Engineering, Osaka City University†

Mechanical and Physical Engineering
Mechanical Engineering
Effect of Pickling and Mechanical Grinding on Initiation of Biofilm and Microbially Influenced
Corrosion of Stainless Steel Weldments
Hiroshi KAWAKAMI, Takuhiro WADA†, Takeshi NAKANISHI, Kingo ARIYOSHI, Kouichi TSUJI,
Masaya KITAMURA and Yasushi KIKUCHI
NACE East Asia & Pacific Area Conference, Yokohama, Japan, November 11-14, 2019.
Temperature Dependence of the Growth Process of Grain Boundary Steps Formed on Ultra-precision
Finished Polycrystalline Copper Surface
Tatsuya USUKI†, Hiroshi KAWAKAMI, Tatsuya TOKUYAMA† and Tsukasa MIYAGAWA†
The 8th International Conference of ASPEN, Asian Society for Precision Engineering and Nanotechnology,
Matsue, Japan, November 12-15, 2019.
Localized Deformation of Electrodeposited Ni-Co-Cu/Cu Multilayered Films Subjected toCompressive Straining
Yoshihisa KANEKO, Tomohiro KUBOMAE† and Makoto UCHIDA
Materials Research Meeting 2019, Yokohama, Japan, December 10-14, 2019.
Dependence of Vickers Hardness on Layer Thickness in Electrodeposited Ni-Co-Cu / Cu Multilayered
Films
Hiroyuki HAGIWARA†, Naofumi KAWAKAMI†, Yoshihisa KANEKO and Makoto UCHIDA
Materials Research Meeting 2019, Yokohama, Japan, December 10-14, 2019.
Numerical Analyses of Micro- to Macroscopic non-Uniform Deformation During Plane Strain
Compression Using Second-Order Homogenization Method
Masashi SAKAMOTO†, Takayuki OTSUKA and Makoto UCHIDAInternational Conference on Computational Plasticity 2019 (Complas 2019), Barcelona, Spain, September
3-5, 2019.
Effect of Metal Type and Heating Condition on Joint Strength of Metal and Polymer Prepared by Arc
Welding
Hiroaki KOBAYASHI†, Makoto UCHIDA, Houichi KITANO and Yoshihisa KANEKO
The 5th International Symposium on Visualization in Joining & Welding Science through Advanced
Measurements and Simulation, Osaka, Japan, November 21-22, 2019.

－67－

Physical Electronics and Informatics
Applied Physics and Electronics
Tunneling of plasma bullets through a dielectric plate and its application to quick hydrophilicity enhancement of bone-regeneration scaffolds
Tatsuru SHIRAFUJI, Yuki HAMAMOTO†, Ryo MATOBA†, Jun-Seok OH, Ryo SUGAMA (Faculty of Medicine), Kumi ORITA (Faculty of Medicine), Hiromitsu TOYODA (Faculty of Medicine)
12th International Symposium on Advanced Plasma Science and its Applications for Nitrides and Nanomaterials/ 13th International Conference on Plasma-Nano Technology & Science, March 8-11, 2020, Nagoya, Japan(Poster)
Plasma generated reactive species deliver onto human dermis model
Kenji MAEDA†, Ikumi TAKAHASHI†, Koji YAMANE†, Miki YANAGISAWA†, Hiroshi KAWAKAMI, Tatsuru
SHIRAFUJI, Jun-Seok OH
12th International Symposium on Advanced Plasma Science and its Applications for Nitrides and Nanomaterials/ 13th International Conference on Plasma-Nano Technology & Science, March 8-11, 2020, Nagoya, Japan(Poster)
Contribution of reactive nitrogen species to sterilization of radical-activated water
Naoyuki IWATA (Meijo University), Vladislav GAMALEEV (Meijo University), Jun-Seok OH, Takayuki
OHTA (Meijo University), Masaru HORI (Nagoya University), Masafumi ITO (Meijo University)
The 11th Asia-Pacific International Symposium on the Basics and Applications of Plasma Technology, December
11-14, 2019, Kanazawa, Japan
Developing pressure gradient sputtering system (PGS)Ken YONEZAWA (Kenix Corporation), Hiroki OOTA (Kenix Corporation), Jun-Seok OH, Kazunori KOGA
(Kyushu University), Tatsuyuki NAKATANI (Okayama University of Science), Masafumi ITO (Meijo University), Masaharu SHIRATANI (Kyushu University)
The 11th Asia-Pacific International Symposium on the Basics and Applications of Plasma Technology, December
11-14, 2019, Kanazawa, Japan (Poster)
Humid air discharge characterization using atmospheric-pressure plasma reactor
Yusuke SASAKI†, Tatsuru SHIRAFUJI, Jun-Seok OH
The 11th Asia-Pacific International Symposium on the Basics and Applications of Plasma Technology, December
11-14, 2019, Kanazawa, Japan (Poster)Spatial distribution of He in a porous scaffold irradiated with He APPJ
Tatsuru SHIRAFUJI, Jun-Seok OH, Ryo SUGAMA (Faculty of Medicine), Kumi ORITA (Faculty of Medicine),
Hiromitsu TOYODA (Faculty of Medicine)The 11th Asia-Pacific International Symposium on the Basics and Applications of Plasma Technology, December
11-14, 2019, Kanazawa, Japan (Poster)
H2O2 synthesis using 3D integrated micro solution plasma and improvement of its efficiency by combining
with ion exchange resin
Tatsuru SHIRAFUJI, Shyoma MIYAMOTO†, Jun-Seok OH
Materials Research Meeting 2019, December 10-14, 2019, Yokohama, Japan (Invited)
Atmospheric-pressure plasma reactor generated plasma-activated water
Jun-Seok OH, Soshi IMAI†, Yusuke SASAKI†, Tatsuru SHIRAFUJI
Materials Research Meeting 2019, December 10-14, 2019, Yokohama, Japan (Invited)
Gas-liquid interfacial plasma polymerization of EDOT
Shoyta HIRANO†, Jun-Seok OH, Ryo KONISHI†, Tatsuru SHIRAFUJI
Materials Research Meeting 2019, December 10-14, 2019, Yokohama, Japan (Poster)－68－

Renovation of water permeability of a continuous porous dielectric using propagation of plasma bullets
Yuki HAMAMOTO†, Tatsuru SHIRAFUJI, Ryo MATOBA†, Jun-Seok OH
Materials Research Meeting 2019, December 10-14, 2019, Yokohama, Japan (Poster)Growth promotion effect of oxygen-radical-treated amino acids solutions
Naoyuki IWATA (Meijo University), Vladislav GAMALEEV (Meijo University), Hiroshi HASHIZIME (Nagoya University), Jun-Seok OH, Takayuki OHTA (Meijo University), Kenji ISHIKAWA (Nagoya University),
Masaru HORI (Nagoya University), Masafumi ITO (Meijo University)
The 29th Annual Meeting of MRS-J, November 27-29, 2019, Yokohama, Japan
Considerations in the development of plasma sources for cosmetic science
Jun-Seok OH, Endre J. SZILI (University of South Australia)
The 1st International Meeting on Plasma Cosmetic Science, November 25-27, 2019, Orleans, France (Poster)
Plasma-bullet propagation behind a dielectric plate irradiated with an APPJ
Tatsuru SHIRAFUJI, Ryo MATOBA†, Yuki HAMAMOTO†, Jun-Seok OH, Ryo SUGAMA (Faculty of Medicine), Kumi ORITA (Faculty of Medicine), Hiromitsu TOYODA (Faculty of Medicine)
The 41st International Symposium on Dry Process, November 21-22, 2019, Hiroshima, Japan (Poster)Discharge characteristics of Ar atmospheric-pressure plasma
Soshi IMAI†, Ikumi TAKAHASHI†, Yusuke SASAKI†, Tatsuru SHIRAFUJI, Jun-Seok OH
The 41st International Symposium on Dry Process, November 21-22, 2019, Hiroshima, Japan (Poster)Longer-lived chemistry and antimicrobial activity of plasma activated water
Jun-Seok OH, Naoyuki IWATA (Meijo University), Giichiro UCHIDA (Meijo University), Kosuke TAKENAKA(Osaka University), Yuichi SETSUHARA (Osaka University), Mineo HIRAMATSU (Meijo University), Masafumi ITO (Meijo University)
The 5th International Symposium on Visualization in Joining & Welding Science through Advanced Measurements and Simulation & The 8th International Conference of Welding Science and Engineering, November 21-22,
2019, Osaka, Japan (Invited)－69－

Electrical and Information Engineering
Spin Transport in Thermally-Evaporated Polyacene Films and the Derivative Films Induced by theSpin-Pumping
Yuji TANAKA†, Taisei KONO†, Masahiro YAMAMOTO†, Yoshio TEKI (Graduate School of Science, OCU),
Hiroaki TSUJIMOTO, Eiji SHIKOH
64th Annual Conference on Magnetism and Magnetic Materials, Las Vegas, USA, November 4-8 (2019).

－70－

Applied Chemistry and Bioengineering
Workshop Instructor on “Micro XRF”
K. TSUJI
69th Annual Conference on Applications of X-ray Analysis Denver X-ray Conference, Rockville, Maryland,
U.S.A., 3-7 August 2020 (invited)
Optimal sample preparation for TXRF analysis depending on the sample solutions
T. MATSUYAMA, K. TSUJI
69th Annual Conference on Applications of X-ray Analysis Denver X-ray Conference, Rockville, Maryland,
U.S.A., 3-7 August 2020 (invited)
X-ray Elemental and Structural Imaging Techniques by using Highly Sensitive X-ray Camera
K. TSUJI, R. OZEKI†, T. MATSUYAMA, M. YAMANASHI
69th Annual Conference on Applications of X-ray Analysis Denver X-ray Conference, Rockville, Maryland,
U.S.A., 3-7 August 2020 (poster)
X-rays analytical techniques for determining trace elements in a single human hair and atmosphericaerosols
T. MATSUYAMA, T. HAYAKAWA, H. YAMAGUCHI, K. TSUJI
69th Annual Conference on Applications of X-ray Analysis Denver X-ray Conference, Rockville, Maryland,
U.S.A., 3-7 August 2020 (poster)
Improvement of Detection Limit for Particle Contamination by Confocal Configuration in X-ray
Fluorescence Microscope
H. NAKANO, S. KOMATANI, T. MATSUYAMA, K. TSUJI
69th Annual Conference on Applications of X-ray Analysis Denver X-ray Conference, Rockville, Maryland,
U.S.A., 3-7 August 2020 (poster)Development of confocal line X-ray fluorescence instrument and application to layer structure samples
S. SONODA†, H. NAKANO, T. MATSUYAMA, K. TSUJI
69th Annual Conference on Applications of X-ray Analysis Denver X-ray Conference, Rockville, Maryland,
U.S.A., 3-7 August 2020 (poster)Multicolor Emission Properties of Polystyrene with Difluoroboron Avobenzone Complexes at Side
Chains in Solid State
Katsuya SHIMIZU†, Arisa OKUMA (Shinshu University), Shiho KATSUMI (Shinshu University), Fuyuki
ITO (Shinshu University), Seiya KOBATAKE
International Research Conference on Engineering and Technology, Seoul, Korea, January 7-9, 2020
(poster)
Outer membrane vesicles of Gram-negative bacteria and its application to microbial biotechnology
Yoshihiro OJIMA, Masayuki AZUMAICGEB-IMBT Workshop2019, I5, Hanoi, Vietnam, November 5-6, 2019－71－

Urban Engineering
Urban Design and Engineering
Vital Reactions as a Measure of Stress Levels in Bicycle Riders According to Task Complexity
Katsumasa TATSUNO†, Nagahiro YOSHIDAThe 8th International Cycling Safety Conference 2019, Brisbane, Australia, 18-20 November 2019.
Extreme Wave and Storm Surge Assessment Due to Typhoon and Low Pressure Weather System on the
Sanin Coast, Japan
Sooyoul KIM, Keishiro CHIYONOBU, Junichi NINOMIYA, Sota NAKAJO, Tomohiro YASUDA, Takao
OTA
The 16th Annual Meeting, AOGS, OS18-A006, Singapore, July 28 – August 2, 2019
The Propagation Characteristics of Micro-barometric Wave Estimated from Observational Data andthe Response of Meteotsunami in the West Kyushu Island
Sota NAKAJOThe first World Conference on Meteotsunamis, Split, Republika Hrvatska, May 8-11, 2019
Low-frequency Catastrophic Coastal Disaster Events around Tonga: Survey of Coastal Boulder
Distribution on Tongatapu Island and Analysis Using Stochastic Modelling of Tropical Cyclones
Sota NAKAJO, J. NINOMIYAThe 29th International Ocean and Polar Engineering Conference, Honolulu, USA, June 17-21, 2019.
Air-Sea CO2 Exchange and Dissolved Inorganic Carbon Distribution in an Inner Part of Osaka Bay,Japan
Toru ENDO, Junpei SHIMANO, Noriko HARADA†, Daiki SAKAI, Ryuichi FUJIWARA
10th International Conference on Asian and Pacific Coastas, 2019, Hanoim Vietnam, September 25-28, 2019.

－72－