bluuebunny/crossref_metadata_2025 huggingface dataset:
Condom use among women of reproductive age (18–49 years) in Puerto Rico during the 2016 Zika virus outbreak: secondary analysis of data from a cross-sectional, population-based, cell-phone survey
Authors: Chang Karen T , Snead Margaret Christine , Serrano Rodriguez Ruby A , Bish Connie , Shapiro-Mendoza Carrie K , Ellington Sascha R
Published: July 2022

Objectives

Zika virus (ZIKV) can be sexually transmitted, and ZIKV infection during pregnancy can cause birth defects. Contraception is a medical countermeasure to reduce unintended pregnancy and ZIKV-associated birth defects. We estimated the prevalence of condom use and associated factors among women at risk for unintended pregnancy in Puerto Rico during the 2016 ZIKV outbreak.

Design

Secondary analysis of a cross-sectional, population-based, cell-phone survey.

Setting and participants

Women, 18–49 years, living in Puerto Rico during July–November 2016. We limited our analytical sample (n=1840) to women at risk for unintended pregnancy, defined as those who were sexually active with a man in the last 3 months and did not report menopause, hysterectomy, current pregnancy or desiring pregnancy.

Outcome measures

We estimated the weighted prevalence of any condom use among women at risk for unintended pregnancy. We calculated crude and adjusted prevalence ratios (aPRs) to examine the association between condom use and ZIKV-related factors, stratified by use of more effective versus less effective or no contraception.

Results

Overall, 32.7% (95% CI: 30.2% to 35.1%) of women reported any condom use in the last 3 months. Among women using more effective contraception, condom use was higher for women who received ZIKV counselling (aPR: 1.61, 95% CI: 1.15 to 2.25) and those worried about having a child with a ZIKV-associated birth defect (aPR: 1.47, 95% CI: 1.03 to 2.10). Among women using less effective or no contraception, condom use was associated with being worried (aPR: 1.20, 95% CI: 1.01 to 1.43) compared with those not worried about ZIKV infection or with a previous known infection.

Conclusions

During the 2016 ZIKV outbreak, one in three women at risk for unintended pregnancy reported any condom use. Counselling to promote consistent and correct condom use may address concerns regarding ZIKV among women of reproductive age, which may differ by use of effective contraception.
Percutaneous alcohol embolization and vertebroplasty of a T2 aggressive vertebral hemangioma with prior embolization of dangerous arterial anastomoses
Authors: Bonnet Baptiste , Shotar Eimad , Premat Kevin , Cormier Evelyne , Beth Adrien , Trebern Hugo , Mahtout Jugurtha , Feydy Antoine , Clarençon Frédéric
Published: July 2022

Aggressive vertebral hemangiomas usually exhibit extraosseous expansion that can result in spinal cord or radicular compression.1 In symptomatic cases, treatment by alcohol embolization and percutaneous vertebroplasty has been reported as feasible, safe, and effective with long-term benefits on neurological symptoms.2

Safety rules before vertebral alcohol embolization include preoperative spinal cord vascularization mapping and opacification through bone needles to assess the absence of dangerous intratumoral anastomoses.

In video 1 we present a case of a symptomatic T2 aggressive vertebral hemangioma with dangerous anastomoses between the lesion and both supreme intercostal arteries (SIAs). Embolization by the arterial route of both SIAs was performed, which required good anatomic knowledge of the spinal cord vascularization at the cervicothoracic junction3 4 as a cervical radiculomedullary artery arose from the left costocervical trunk which also fed the left SIA. After occlusion of all dangerous arterial anastomoses, we were able to successfully perform T2 alcohol embolization and percutaneous vertebroplasty.

Video 1

Case presentation
Increased risk of incident knee osteoarthritis in those with greater work-related physical activity
Authors: Lo Grace H , Richard Michael J , McAlindon Timothy E , Park Chantel , Strayhorn Michael T , Harkey Matthew S , Price Lori Lyn , Eaton Charles B , Driban Jeffrey B
Published: July 2022

Objective

Occupations involving greater physical activity may increase risk for knee osteoarthritis (OA). Existing studies have not evaluated work-related physical activity before OA onset. Hence, we aimed to evaluate the association between work-related physical activity and knee OA incidence.

Methods

We performed a person-based longitudinal study using Osteoarthritis Initiative (OAI) data among people who volunteered or worked for pay without baseline radiographic knee OA or knee pain. Bilateral knee radiographs were obtained at baseline and annual follow-ups. We defined radiographic OA as Kellgren-Lawrence grade ≥2. Questions from the Physical Activity Scale for the Elderly at baseline and annual OAI visits provided information about work-related physical activity level and hours. We performed logistic regression with work-related physical activity level (mainly sitting,standing and some walking,walking while handling some materials) and hours as predictors. The outcome was incident person-based radiographic OA within the ensuing 12 months, over 48 months.

Results

Among 951 participants (2819 observations), higher work-related physical activity levels had greater adjusted ORs for incident radiographic OA (people with jobs withstanding and some walking: 1.11 (0.60–2.08), andwalking while handling some materials: 1.90 (1.03–3.52), when compared with those withmainly sitting work-related activity). There was no association between number of hours worked and incident radiographic OA.

Conclusions

People performing work that require walking while handling some materials have greater odds of incident knee OA than those with jobs mostly involving sitting. Strategies are needed to mitigate risk factors predisposing them to radiographic OA.
Which fish is this? Fishers know more than 100 fish species in megadiverse tropical rivers
Authors: Silvano Renato A. M. , Pereyra Paula E. R. , Begossi Alpina , Hallwass Gustavo
Published: July 2022

Ethnobiological studies on folk, common, or popular names that fishers use to identify fish can help improve fisheries monitoring and collaborations between fishers and researchers. This study investigates fishers’ knowledge (recognition, naming, and habitat use) on 115 and 119 fish species, respectively, in the Negro and Tapajos Rivers, two megadiverse rivers in the Brazilian Amazon, and investigates the relationship between such knowledge and fish importance to fisheries, fish abundance, and fish size. We also compared fishers’ perceptions on fisheries and fish abundance with literature data on fish harvests and fish sampling. We interviewed 16 fishers in 16 communities (one fisher per community, 8 communities along each river). These fishers recognized an average of 91 ± 10.4 species in the Negro River and 115 ± 7.2 species in the Tapajos River, but all fishers recognized 114 species in Negro and all species in Tapajos. The fishers’ knowledge of fish species was positively related to fishers’ perceptions on fish abundance, size, and importance to fisheries in the Negro, but only positively related to fish size in the Tapajos. Our results highlight the usefulness of fishers’ knowledge to providing data on use and cultural relevance of fish species in high diversity aquatic ecosystems.
Upsilon decay widths in magnetized asymmetric nuclear matter
Authors: Mishra Amruta , Misra S. P.
Published: July 2022

The in-medium partial decay widths of [Formula: see text] in magnetized asymmetric nuclear matter are studied using a field theoretic model for composite hadrons with quark (and antiquark) constituents. [Formula: see text] is the lowest bottomonium state which can decay to [Formula: see text] in vacuum. The medium modifications of the decay widths of [Formula: see text] to [Formula: see text] pair in magnetized matter arise due to the mass modifications of the decaying [Formula: see text] as well as of the produced [Formula: see text] and [Formula: see text] mesons. The in-medium masses of the open bottom meson in magnetized nuclear matter are computed from their interactions with the nucleons and the scalar mesons within a chiral effective model. The mass modification of the [Formula: see text] arises due to the medium modification of a scalar dilaton field, which is introduced in the model to simulate the gluon condensates of QCD. The effects of the anomalous magnetic moments for the proton and neutron are taken into consideration in the present investigation. The presence of the external magnetic field is observed to lead to different mass modifications within the [Formula: see text] as well as the [Formula: see text] doublets, even in isospin symmetric nuclear matter. This is due to the difference in the interactions of the proton and the neutron to the electromagnetic field. The charged [Formula: see text] mesons have additional contributions from the Landau energy levels, leading to positive shifts in their masses in the presence of a magnetic field. In the presence of an external magnetic field, there are contributions to the masses of the B, [Formula: see text] mesons and [Formula: see text] state (longitudinal component) due to the pseudoscalar meson–vector meson (PV) mixing ([Formula: see text], [Formula: see text] and [Formula: see text] mixings), which are also considered in this study. The PV mixing effects are observed to be the dominant contributions to the mass shifts of these mesons, which lead to appreciable modifications in the decay widths of [Formula: see text] to the neutral ([Formula: see text]) and the charged ([Formula: see text]) pairs in the presence of a magnetic field. These should have observable consequence in the production of open bottom mesons and bottomonium states at LHC and RHIC, where huge magnetic fields are produced in ultra-relativistic peripheral heavy-ion collisions.
Adaptive Text Denoising Network for Image Caption Editing
Authors: Yuan Mengqi , Bao Bing-Kun , Tan Zhiyi , Xu Changsheng
Published: July 2022

Image caption editing, which aims at editing the inaccurate descriptions of the images, is an interdisciplinary task of computer vision and natural language processing. As the task requires encoding the image and its corresponding inaccurate caption simultaneously and decoding to generate an accurate image caption, the encoder-decoder framework is widely adopted for image caption editing. However, existing methods mostly focus on the decoder, yet ignore a big challenge on the encoder: the semantic inconsistency between image and caption. To this end, we propose a novel
A
daptive
T
ext
D
enoising
Net
work (ATD-Net) to filter out noises at the word level and improve the model’s robustness at sentence level. Specifically, at the word level, we design a cross-attention mechanism called Textual Attention Mechanism (TAM), to differentiate the misdescriptive words. The TAM is designed to encode the inaccurate caption word by word based on the content of both image and caption. At the sentence level, in order to minimize the influence of misdescriptive words on the semantic of an entire caption, we introduce a Bidirectional Encoder to extract the correct semantic representation from the raw caption. The Bidirectional Encoder is able to model the global semantics of the raw caption, which enhances the robustness of the framework. We extensively evaluate our proposals on the MS-COCO image captioning dataset and prove the effectiveness of our method when compared with the state-of-the-arts.
Design of a Novel Information System for Semi-automated Management of Cybersecurity in Industrial Control Systems
Authors: Ameri Kimia , Hempel Michael , Sharif Hamid , Lopez Juan , Perumalla Kalyan
Published: July 2022

There is an urgent need in many critical infrastructure sectors, including the energy sector, for attaining detailed insights into cybersecurity features and compliance with cybersecurity requirements related to their Operational Technology (OT) deployments. Frequent feature changes of OT devices interfere with this need, posing a great risk to customers. One effective way to address this challenge is via a semi-automated cyber-physical security assurance approach, which enables verification and validation of the OT device cybersecurity claims against actual capabilities, both pre- and post-deployment. To realize this approach, this article presents new methodology and algorithms to automatically identify cybersecurity-related claims expressed in natural language form in ICS device documents. We developed an identification process that employs natural language processing (NLP) techniques with the goal of semi-automated vetting of detected claims against their device implementation. We also present our novel NLP components for verifying feature claims against relevant cybersecurity requirements. The verification pipeline includes components such as automated vendor identification, device document curation, feature claim identification utilizing sentiment analysis for conflict resolution, and reporting of features that are claimed to be supported or indicated as unsupported. Our novel matching engine represents the first automated information system available in the cybersecurity domain that directly aids the generation of ICS compliance reports.
The Tip of the Buyer: Extracting Product Tips from Reviews
Authors: Hirsch Sharon , Novgorodov Slava , Guy Ido , Nus Alexander
Published: July 2022

Product reviews play a key role in e-commerce platforms. Studies show that many users read product reviews before a purchase and trust them to the same extent as personal recommendations. However, in many cases, the number of reviews per product is large and extracting useful information becomes a challenging task. Several websites have recently added an option to post
tips
—short, concise, practical, and self-contained pieces of advice about the products. These tips are complementary to the reviews and usually add a new non-trivial insight about the product, beyond its title, attributes, and description. Yet, most if not all major e-commerce platforms lack the notion of a tip as a first-class citizen and customers typically express their advice through other means, such as reviews.

In this work, we propose an extractive method for tip generation from product reviews. We focus on five popular e-commerce domains whose reviews tend to contain useful non-trivial tips that are beneficial for potential customers. We formally define the task of tip extraction in e-commerce by providing the list of tip types, tip timing (before and/or after the purchase), and connection to the surrounding context sentences. To extract the tips, we propose a supervised approach and leverage a publicly available dataset, annotated by human editors, containing 14,000 product reviews. To demonstrate the potential of our approach, we compare different tip generation methods and evaluate them both manually and over the labeled set. Our approach demonstrates particularly high performance for popular products in the Baby, Home Improvement, and Sports & Outdoors domains, with precision of over 95% for the top 3 tips per product. In addition, we evaluate the performance of our methods on previously unseen domains. Finally, we discuss the practical usage of our approach in real-world applications. Concretely, we explain how tips generated from user reviews can be integrated in various use cases within e-commerce platforms and benefit both buyers and sellers.
PRNU-based Image Forgery Localization with Deep Multi-scale Fusion
Authors: Zhang Yushu , Tan Qing , Qi Shuren , Xue Mingfu
Published: July 2022

Photo-response non-uniformity (PRNU), as a class of device fingerprint, plays a key role in the forgery detection/localization for visual media. The state-of-the-art PRNU-based forensics methods generally rely on the multi-scale trace analysis and result fusion, with Markov random field model. However, such hand-crafted strategies are difficult to provide satisfactory multi-scale decision, exhibiting a high false-positive rate. Motivated by this, we propose an end-to-end multi-scale decision fusion strategy, where a mapping from multi-scale forgery probabilities to binary decision is achieved by a supervised deep fully connected neural network. As the first time, the deep learning technology is employed in PRNU-based forensics for more flexible and reliable integration of multi-scale information. The benchmark experiments exhibit the state-of-the-art accuracy performance of our method in both pixel-level and image-level, especially for false positives. Additional robustness experiments also demonstrate the benefits of the proposed method in resisting noise and compression attacks.
Cybersecurity Challenges in the Offshore Oil and Gas Industry: An Industrial Cyber-Physical Systems (ICPS) Perspective
Authors: Mohammed Abubakar Sadiq , Reinecke Philipp , Burnap Pete , Rana Omer , Anthi Eirini
Published: July 2022

There has been significant interest within the offshore oil and gas industry to utilise
Industrial Internet of Things (IIoT)
and
Industrial Cyber-Physical Systems (ICPS)
. There has also been a corresponding increase in cyberattacks targeted at oil and gas companies. Offshore oil production requires remote access to and control of large and complex hardware resources. This is achieved by integrating ICPS,
Supervisory, Control and Data Acquisition (SCADA)
systems, and IIoT technologies. A successful cyberattack against an
oil and gas (O&G)
offshore asset could have a major impact on the environment, marine ecosystem and safety of personnel. Any disruption to the world’s supply of O&G can also have an effect on oil prices and the global economy. We describe the cyberattack surface within the oil and gas industry, discussing emerging trends in the offshore sub-sector and provide a historical perspective of known cyberattacks. We also present a case study of a subsea control system architecture typically used in offshore O&G operations and highlight potential vulnerabilities affecting the components of the system. This study is the first to provide a detailed analysis of attack vectors in a subsea control system. The analysis provided can be used to understand key vulnerabilities in such systems and may be used to implement efficient mitigation methods.
(Invited, Digital Presentation) Uniqueness of Cobalt-Tungsten Intermetallic Compounds in Catalyzing Single-Walled Carbon Nanotube Growth
Authors: Li Yan
Published: July 2022

The intermetallic Co7W6 catalysts have shown great success in chirality-specified growth of single-walled carbon nanotubes (SWCNTs). Electron microscopic techniques, particularly the in-situ techniques enable us to study the growth mechanism and the behavior of catalysts at atomic scale. It was found that the structure of Co7W6 nanocrystals were stable at the temperature of 1100 °C under carbon feeding condition. No carbon dispersion within the nanocrystal happened. These observations illustrate why such kind of catalysts can act as the structural template to grow SWCNTs with specified chiralities. Due to the less efficient carbon diffusion and supply on the surface of catalysts in such a vapor-solid-solid process than that in a vapor-liquid-solid process, SWCNTs normally nucleate on larger catalyst nanocrystals. All these behaviors are distinctly different from those of normal metallic catalysts, demonstrating the uniqueness of intermetallic Co7W6 catalysts in chirality-selective growth of SWCNTs. These results can help us to further understand the mechanism of the origination of chirality selectivity in SWCNT growth, benefiting the rational design of catalysts.
(Invited) Production and Functionalization of Carbon Nanotubes for Electrochemical Energy Storage Devices
Authors: Noda Suguru
Published: July 2022

Self-supporting, sponge-like paper of carbon nanotubes (CNTs) can be a new platform for high energy/power density batteries. Presently, battery electrodes are built on metallic foils having only two faces and large mass with the aid of polymeric binders and conductive fillers. CNT paper can replace all these components. Furthermore, it captures nanomaterials at high loading, activates insulative materials, and moderates volumetric change of active materials.

We have developed semi-continuous fluidized bed chemical vapor deposition method [1], which yields submillimeter-long few-wall CNTs with carbon purity >99 wt% and metal impurity <0.1 wt% [2]. By capturing capacitive particles (99 wt%) with CNTs (1 wt%), a lithium ion full cell with graphite-CNT anode and LiCoO2-CNT cathode is demonstrated (Figure 1b) [3]. This platform is also effective to create electrodes of the emerging active materials such as Si anode [4] and S cathode [5] with practically high gravimetric, areal, and volumetric loadings, and realized Li
x
Si-S and Li-Li2S
x
full cells [6,7]. In addition, by combining with the insulative sponge of boron nitride nanotubes (BNNTs), the graphite-CNT|BNNT| LiCoO2-CNT full cell with high thermal stability was developed [8].

[1] D.Y. Kim, et al., Carbon 49, 1972 (2011).

[2] Z. Chen, et al., Carbon 80, 339 (2014).

[3] K. Hasegawa and S. Noda, J. Power Sources 321, 155 (2016).

[4] T. Kowase, et al., J. Power Sources 363, 450 (2017).

[5] K. Hori, et al., J. Phys. Chem. C 123, 3951 (2019).

[6] K. Hori, et al., Carbon 161, 612-621 (2020).

[7] Y. Yoshie, et al., Carbon 182, 32-41 (2021).

[8] K. Kaneko, et al., Carbon 167, 596-600 (2020).

Figure 1. (a) Semi-continuous production of submillimeter-long few-wall CNTs by fluidized bed [1]. (b) Lithium ion full cell made of graphite-CNT anode and LiCoO2-CNT cathode [3].

Figure 1
(Invited) Deterministic Transfer of Optical-Quality Carbon Nanotubes for Atomically Defined Technology
Authors: Otsuka Keigo , Fang Nan , Yamashita Daiki , Taniguchi Takashi , Watanabe Kenji , Kato Yuichiro K.
Published: July 2022

When continued device scaling reaches the ultimate limit imposed by atoms, technology based on atomically precise structures is expected to emerge. Device fabrication will then require building blocks with identified atomic arrangements and assembly of the components without contamination. Here we report on a versatile dry transfer technique for deterministic placement of optical-quality carbon nanotubes [1]. Single-crystalline anthracene is used as a medium which readily sublimes by mild heating, leaving behind clean nanotubes and thus enabling bright photoluminescence. We are able to position nanotubes of a desired chirality with a sub-micron accuracy under in-situ optical monitoring, thereby demonstrating deterministic coupling of a nanotube to a photonic crystal nanobeam cavity. A cross junction structure is also designed and constructed by repeating the nanotube transfer, where intertube exciton transfer is observed. Our results represent an important step towards development of devices consisting of atomically precise components and interfaces.

Parts of this study are supported by JSPS (KAKENHI JP20H02558, JP19J00894, JP20K15137), MIC (SCOPE 191503001), and MEXT (Nanotechnology Platform JPMXP09F19UT0075). Growth of hexagonal boron nitride crystals is supported by the Element Strategy Initiative conducted by the MEXT (JPMXP0112101001), JSPS (KAKENHI JP20H00354), and JST (CREST JPMJCR15F3). K.O. and D.Y. are supported by JSPS (Research Fellowship for Young Scientists). N.F. is supported by RIKEN Special Postdoctoral Researcher Program. We thank T. Inoue, S. Maruyama, and K. Nagashio for help in the material preparation, as well as the Advanced Manufacturing Support Team at RIKEN for technical assistance.

[1] K. Otsuka, N. Fang, D. Yamashita, T. Taniguchi, K. Watanabe, Y. K. Kato, Nat. Commun.12, 3138 (2021).
(Invited) Carbon Nanotube Thin-Film Devices for Fully-Flexible Electronics
Authors: Ohno Yutaka
Published: July 2022

Since flexible electronic devices can come in close contact with soft human tissue, they are suitable as wearable sensor applications for long-term and non-invasive monitoring of biological signals in a wide range of fields such as medical/health care, sports, and so on. Previous flexible sensor systems require signal processing with either a remote terminal or rigid IC chips placed on the sensor device due to the lack of high-performance flexible analog-frontend circuit (AFE). The remote system may suffer from an incorporation of external noise. The use of rigid IC chips degrades the flexibility and durability of the wearable sensor. To realize a fully flexible sensor system, an AFE including amplifiers, filters, analog-digital converters is needed to be integrated as well as sensors monolithically on a flexible substrate. In this study, we have realized fully-flexible AFE with carbon nanotubes. The key circuit is a novel operational amplifier (op-amp) with a high gain and low operating voltage. The AFE can be operated at low-voltage and exhibits excellent stability and robustness against variability.
(Invited, Digital Presentation) Exciton Controlled-NOT Gate Realized By Carbon Nanotube Coupled Quantum Dots
Authors: Hida Akira , Ishibashi Koji
Published: July 2022

Among various methods for constructing the quantum bits (qubits) required to perform the quantum computing, there is the concept to use the exciton in nano-structured material such as semiconductor quantum dot (QD), colloidal nanocrystal, or molecule. When the presence/absence of exciton is associated with two-level system of |1>/|0>, the Rabi oscillation of exciton serves as a basis for one-qubit operation. In order to realize the controlled-NOT (CNOT) gate which is essential for the quantum computing, one needs four-level system consisting of two qubits (i.e., |0>|0>, |1>|0>, |0>|1>, and |1>|1>). The construction of exciton CNOT gate is theoretically possible, however, the experimental demonstration has not been conducted. The optical processes of carbon nanotubes are governed by excitons. We attempted to realize the exciton CNOT gate by using the coupled QDs formed in a carbon nanotube.

We fabricated two QDs by terminating both ends of a single-walled carbon nanotube (SWNT) with the collagen model peptides via peptide bonds. The scanning tunneling microscopy and spectroscopy measurements revealed that two QDs of ~ 3.1 nm and ~ 3.9 nm in widths, respectively, were formed in that SWNT with the inter-dot spacing of ~ 5.4 nm. It was confirmed by observing the Rabi oscillations that each QD acted as the exciton two-level system. When the excitons were produced in both QDs, additional exciton emission lines appeared, which may be originating from the coupled state of excitons across two QDs. We define the exciton four-level system as follows; |0>|0> when both QDs are empty, |1>|0>/|0>|1> when exciton is present in either of two QDs, and |1>|1> when excitons coupled across two QDs are generated. |1>|0>, |0>|1>, or |1>|1> could be prepared by irradiating the corresponding π pulse determined from the Rabi oscillation.

The CNOT gate consists of a control qubit and a target qubit, and the logic of the target qubit is flipped only if the control qubit is in logic |1>. When we regard two QDs in our sample as a pair of control qubit and target qubit, the conditional flip of the target qubit corresponds to the π pulse-induced transition between |1>|1> and |1>|0> or between |1>|1> and |0>|1> depending on which QD we choose for the target qubit. The exciton CNOT gate operations were executed by irradiating that π pulse onto the states prepared as inputs. The input/output relations were measured in both ZZ and XX bases, which allowed us to estimate the quantum process fidelity. Our exciton CNOT gate actualized the expected operations whichever QD we used as the target qubit. By executing the CNOT gate operations three times, logic exchange is made between |1>|0> and |0>|1>, which is called the SWAP gate. It was also ascertained that the exchange of the exciton population took place between two QDs when conducting the SWAP operation by applying our CNOT gate.
A Simple and Scalable Wet Etching Method for Graphene Patterning By Using Hypochlorite and Ultraviolet Light
Authors: Zhang Minfang , Yang Mei , Okigawa Yuki , Yamada Takatoshi , Nakajima Hideaki , Iizumi Yoko , Okazaki Toshiya
Published: July 2022

Graphene patterning via etching is important for enhancing or controlling the properties of devices and supporting their applications in micro- and nano-electronic fields. Herein, we present a simple, low-cost, and scalable wet etching method for graphene patterning. The technique uses hypochlorite solution combined with ultraviolet light irradiation to rapidly remove unwanted graphene areas from the substrate. Raman spectroscopy, atomic force microscopy, scanning electron microscopy, and optical microscopy results showed that well-patterned graphene with micrometer scale regions was successfully prepared. Furthermore, graphene field effect transistor arrays were fabricated, and the obtained devices exhibited good current-voltage characteristics, with maximum mobility of ~1600 cm2/Vs, confirming the feasibility of the developed technique.
(Invited) Graphenemesosponge: A New Carbon Material with High Porosity and High Durability for Battery Applications
Authors: Nishihara Hirotomo
Published: July 2022

There are many kinds of carbon materials such as activated carbons, nanoporous carbons, carbon blacks, graphite, carbon nanotubes, carbon nanofibers, and graphene-like materials, and they have been used in a variety of batteries as active materials, conductive additives, and gas diffusion layers. Depending on the purpose of use, carbon materials are required to have appropriate porosity, electric conductivity, mechanical stability, and electrochemical stability. While the above mentioned carbon materials have individual advantages and disadvantages, it has been a challenging target to develop next-generation carbon materials to satisfy all the necessary requirements at the same time. In this talk, a new class of carbon material, “graphene mesosponge (GMS)”, is introduced as a feasible candidate [1]. GMS is synthesized by a hard-templating method using Al2O3 [1] or MgO [2] nanoparticles via precisely controlled chemical-vapor deposition in which the average stacking number of graphene sheets is adjusted to 1. After template removal, the resulting mesoporous carbon is annealed at 1800 °C to form GMS. By such a high-temperature treatment, most of carbon edge sites which cause corrosion of batteries can be removed, and GMS exhibits ultra-high stability against chemical oxidation as well as electrochemical oxidation. Despite such durability, GMS possess a high surface area (ca. 2000 m2/g) and a large pore volume (> 3 cm3/g). Moreover, GMS has a high electric conductivity which is superior to carbon blacks. Furthermore, GMS is mechanically flexible and tough. GMS shows reversible deformation and recovery upon applying mechanical force and its removal [3]. Such unique properties of GMS enable its use as next-generation durable and high-performance carbon material to battery applications. As an electrode material for electric double-layer capacitors, GMS exhibits ultra-high voltage stability up to 4.4 V even in a conventional organic electrolyte (Et3MeN/BF4), which surpass single-walled carbon nanotubes [4]. Also, GMS is useful to a Pt support of polymer-electrolyte fuel cells [5] and to a cathode of Li-air batteries.

References

[1] H. Nishihara, T. Simura, S. Kobayashi, K. Nomura, R. Berenguer, M. Ito, M. Uchimura, H. Iden, K. Arihara, A. Ohma, Y. Hayasaka, T. Kyotani, Adv. Funct. Mater. 2016, 26, 6418-6427.

[2] S. Sunahiro, K. Nomura, S. Goto, K. Kanamaru, R. Tang, M. Yamamoto, T. Yoshii, J. N. Kondo, Q. Zhao, A. Ghulam Nabi, R. Crespo-Otero, D. Di Tommaso, T. Kyotani, H. Nishihara, J. Mater. Chem. A 2021, 9, 14296-14308.

[3] K. Nomura, H. Nishihara, M. Yamamoto, A. Gabe, M. Ito, M. Uchimura, Y. Nishina, H. Tanaka, M. T. Miyahara, T. Kyotani, Nat. Commun. 2019, 10, 2559.

[4] K. Nomura, H. Nishihara, N. Kobayashi, T. Asada, T. Kyotani, Energy Environ. Sci. 2019, 12, 1542-1549.

[5] A. Ohma, Y. Furuya, T. Mashio, M. Ito, K. Nomura, T. Nagao, H. Nishihara, H. Jinnai, T. Kyotani, Electrochim. Acta 2021, 370, 137705.
(Invited, Digital Presentation) Ultrathin Lateral Heterostructures Based on Two-Dimensional Semiconductors
Authors: Kitaura Ryo
Published: July 2022

Low-dimensional (2D) materials, including carbon nanotubes, graphene, boron nitrides, and transition metal dichalcogenides (TMDs), have provided a platform to explore novel physics at the nano-scale. In addition to the fascinating properties of low-dimensional materials themselves, they allow exploring novel superstructures, such as heterojunctions, heterostacks, and superlattices, which give even broader possibilities. We are working on low-dimensional superstructures fabricated by (1) crystal growth with metal-organic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE), and (2) stacking each component with the full-dry-transfer-based manipulation technique[1]-[6].

This presentation will focus on our recent works on low-dimensional superstructures, such as 2D ultrathin lateral superlattices. For example, we have successfully realized MoS2/WS2 2D lateral superlattices with a periodicity of down to one-atom-thick by MOCVD with an automatic valve control system. Also, we have observed characteristic PL arising probably from 1D junction structures. More details on the fabrication and optical properties of these superstructures will be addressed in this talk.

[1] Y. Murai, et. al., ACS Nano 2021, doi.org/10.1021/ascnano.1c04584

[2] T. Hotta, et. al., ACS Nano 2021, 51:1370-1377.

[3] T. Hotta, et al., Phys. Rev. B 2020, 102:115424.

[4] S. Zhao et al., Phys. Rev. Lett. 2020, 124:106101.

[5] Y. Uchiyama et. al., npj 2D Mater. App. 2019, 3:26.

[6] M. Okada, et. al., ACS Nano 2018, 12:2498-2505.
(Invited, Digital Presentation) 50 Ns Ultrafast Memory Operation in 2D Heterostructured Non-Volatile Memory Device
Authors: Nagashio Kosuke
Published: July 2022

2D heterostructures have been extensively investigated as next-generation non-volatile memory (NVM) devices. In the last decade, drastic performance improvements and further advanced functionalities have been demonstrated. However, this progress is not sufficiently supported by the understanding of their operations, obscuring the material and device structure design policy. Here, detailed operation mechanisms are elucidated by exploiting the floating gate voltage (V
FG) trajectory measurements [1,2]. Systematic comparisons of MoTe2, WSe2, and MoS2 channel devices revealed that the tunneling behavior between the channel and FG is controlled by three kinds of current-limiting paths, i.e., tunneling barrier, 2D/metal contact, and pn junction in the channel. Based on the understanding of the memory operation mechanism through the V
FG trajectory measurement, we propose the best all 2D NVM device structure with a direct tunneling path between source/drain electrodes and floating gate for ultrafast memory operation. Indeed, a 50 ns program/erase operation is successfully achieved [3]. Moreover, we examined the dielectric breakdown strength (E
BD) of h-BN under short voltage pulses for the origin for this ultrafast operation, because a high dielectric breakdown strength allows a large tunneling current. Surprisingly, an E
BD = 26.1 MV/cm for h-BN is realized under short voltage pulses, largely exceeding the E
BD = ~12 MV/cm from the DC measurement. This suggests that the high E
BD of h-BN can be the physical origin of the ultrafast operations. In this talk, I would like to discuss the future perspective of 2D NVM application.

[1] T. Sasaki, KN, et al., "Understanding the Memory Window Overestimation of 2D Materials Based Floating Gate Type Memory Devices by Measuring Floating Gate Voltage", Small, 2020, 16, 2004907.

[2] T. Sasaki, KN, et al., "Material and Device Structure Designs for 2D Memory Devices Based on the Floating Gate Voltage Trajectory", ACS nano, 2021, 15, 6658.

[3] T. Sasaki, KN, et al., "Ultrafast Operation of All 2D-Heterostructured Nonvolatile Memory Devices Provided by the Strong Short-Time Dielectric Breakdown Strength of h-BN", Adv. Funct. Mater. (under revision).
(Invited, Digital Presentation) Molecular Nanocarbon Synthesis and Beyond
Authors: Itami Kenichiro
Published: July 2022

Our goal is the creation of super molecules, innovative functional molecules with significant properties and/or beautiful molecules. To this end, we have focused on catalyst-enabling synthetic chemistry with broad directions, including applications in molecular nanocarbons, pharmaceuticals, and plant/animal chemical biology, and the development of rapid molecule-assembly methods using unique catalysts. In particular, we have pioneered molecular nanocarbon science by the bottom-up synthesis of structurally uniform nanocarbons of fundamental and practical importance. Representative achievements include: (1) the development of single-step aromatic π-extension (APEX) methods for the rapid and programmable synthesis of nanocarbon molecules (Science 2018, Nature Commun. 2015, Nature Chem. 2015, Nature Commun. 2021); (2) the synthesis of carbon nanorings, nanobelts and pure nanotubes (ACIE 2009, Science 2017, Nature Chem. 2013, Nature Commun. 2018, Nature Commun. 2019, Nature Chem. 2021); and (3) the synthesis of topologically unique nanocarbons such as warped nanographenes, carbon nanocages, all-benzene catenanes, and trefoil knots (Science 2019, Nature Chem. 2013, Nature Catal. 2020). In this talk, most recent beautiful molecular nanocarbons will be presented. We will also describe about our exciting interdisciplinary research conducted at the Institute of Transformative Bio-Molecules (ITbM) in Nagoya University and Institute of Chemistry in Academia Sinica, Taiwan, where we aim at developing game-changing molecules for nanocarbon-based chemical biology. By using our original rapid molecule-assembling catalysts, a number of lead compounds were rapidly discovered.
(Invited) Sumanenyl Cations As Redox-Active Buckybowls
Authors: Sakurai Hidehiro
Published: July 2022

Sumanene is one of the pristine buckybowls, which possesses C3v symmetric fragment of C60. The most characteristic feature of its structure is that sumanene has three benzylic positions on its periphery, therefore, potentially 6 electron redox systems are considered from the corresponding trianions to trications. In this presentation, I demonstrate the generation of the trication or monocation species of aryl-substituted sumanene derivatives, and show some properties including the redox propertiy.
(Invited) Novel Acene-Based Molecules and Materials for Singlet Fission
Authors: Hasobe Taku
Published: July 2022

Singlet fission (SF) is a multi-exciton generation process in two neighboring organic chromophores (S1 + S0) where two individual triplet excitons (T1 + T1) are generated from one-photon absorption through a correlated triplet pair (TT). Therefore, SF is highly promising for construction of next-generation light energy conversion systems and quantum information science. In addition to the close interaction of two neighboring chromophores, energy-level matching condition between a singlet and two triplet states: [E(S1) ≥ 2E(T1)] are required for efficient SF.

Observation of SF was widely discussed under various condition such as solid-state films and covalently-linked molecular dimers in homogeneous solution. In contrast, inorganic nanomaterials such as quantum dots and metal nanoclusters demonstrated the characteristic optical and electrochemical properties as compared to organic molecules. However, the number of organic-inorganic hybrid systems for efficient SF is extremely limited.1-3 Furthermore, there are no reports regarding SF systems using liquid molecules.4 In this presentation, we present our recent research results regarding novel acene-based molecules and materials for SF.

References

Sakai, H.; Inaya, R.; Tkachenko, N. V.; Hasobe, T. Chem. Eur. J.
2018,
24, 17062-17071.

Saegusa, T.; Sakai, H.; Nagashima, H.; Kobori, Y.; Tkachenko, N. V.; Hasobe, T. J. Am. Chem. Soc.
2019,
141, 14720-14727.

Zhang, J.; Sakai, H.; Suzuki, K.; Hasobe, T.; Tkachenko, N. V.; Chang, I. Y.; Hyeon-Deuk, K.; Kaji, H.; Teranishi, T.; Sakamoto, M. J. Am. Chem. Soc.
2021,
143, 17388-17394.

Yoshino, K.; Sakai, H.; Shoji, Y.; Kajitani, T.; Anetai, H.; Akutagawa, T.; Fukushima, T.; Tkachenko, N. V.; Hasobe, T. J. Phys. Chem. B
2020,
124, 11910-11918.
(Invited) Toward Nanocarbon Materials-Based Organic and Perovskite Solar Cells
Authors: Matsuo Yutaka , Lin Hao-Sheng
Published: July 2022

In this presentation, we introduce our recent research progress on organic and perovskite solar cells using functionalized nanocarbon materials. We applied wet-processed scalable single-walled carbon nanotubes (SWCNT) films to transparent and back electrodes in organic solar cells for large area solar cells. Gas-phase growth SWCNT was dispersed with sodium dodecylbenzenesulfonate surfactant in an organic solvent and solution-coated on a treated glass substrate to make a SWCNT film as a transparent electrode. We achieved the first high efficiency e-DIPS/wet-processed SWCNT film electrode in organic solar cells with a best-efficiency of 5.93% through the optimized HNO3 doping methodology.

We also report enhanced hole-transporting ability of widely utilized poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) achieved by applying cationic nitrogen-doped graphene (CNG) as a p-type modifier for efficient organic solar cells. The power conversion efficiency of the CNG-coated PEDOT:PSS-applied OSC reaches 2.76% using poly(3-hexylthiophene), which is an increase of 40% compared to that of the pristine PEDOT:PSS-applied OSC (1.96%). This technology improved the efficiency of organic solar cells using a low-bandgap polymer from 6.54% to 7.79%. The significantly enhanced performance is contributed by the increased hole-transporting ability, and the improved interfacial morphology of PEDOT:PSS.
(Invited, Digital Presentation) Heterogeneously Integrated Nanomaterial-Based Multimodal Flexible Sensor Sheets
Authors: Takei Kuniharu
Published: July 2022

Human interaction is of great interests for a next class of human society to realize convenient, comfortable, and safe life. For this purpose, multimodal sensing is one of the most important functionalities. Furthermore, without sacrificing the original shape change or uncomfortability to attach or wear the sensor systems onto the targeted surface, respectively, ultrathin and mechanically flexible sensor is required. To address these requirements together, one potential material system is inorganic nanomaterials, which allows it to achieve a variety of material integrated formation on a film and mechanical flexibility due to ultra-small dimensions with high performance. However, the challenges to utilize the nanomaterials for the practical flexible device applications are still remained such as scalability, long-time stability, and multi-functional integrations. In my group, we are trying to develop the heterogeneously integrated nanomaterial-based sensors on flexible films to overcome all challenges to move forward to building the new sensor platforms.

In this talk, as the progress on our research activity to contribute the flexible sensor community and IoT applications, multimodal flexible sensors using mainly nanomaterials formed by solution-based and laser-induced methods are discussed for wearable healthcare/medical applications. In addition to the flexible sensors, wireless system and signal processing for the feedback alarm function when the abnormal signal is detected are introduced as the potential flexible sensor application. In particular, electrocardiogram (ECG), skin temperature, and skin humidity flexible sensors and their integration on a flexible film are explained by using fundamental characteristics.

This study focuses on the heterogeneously integrated multimodal flexible sensors for the application of remote healthcare applications. Although additional functional sensors and systems to realize more useful and convenient home-use healthcare system is required, the approaches may contribute the further developments to open a next class of electronics for IoT.
Microcantilever: An Unique Apparatus to Revolve the Mechanical Stress in Batteries
Authors: Jiang Keren , Thundat Thomas , Li Zhi
Published: July 2022

Although the generation of mechanical stress in the anode material is suggested as a possible reason for electrode degradation and fading of storage capacity in batteries, only limited knowledge of the electrode stress and its evolution is available at present. Here, we show real-time monitoring of the interfacial stress of a few-layer MoS2 system under the sodiation/desodiation process using microcantilever electrodes. During the first sodiation with a voltage plateau of 1.0 to 0.85 V, the MoS2 exhibits a compressive stress (2.1 Nm−1), which is substantially smaller than that measured (9.8 Nm−1) during subsequent plateaus at 0.85 to 0.4 V due to the differential volume expansion of the MoS2 film. The conversion reaction to Mo below 0.1 V generates an anomalous compressive stress of 43 Nm−1 with detrimental effects. These results also suggest the existence of a separate discharge stage between 0.6 and 0.1 V, where the generated stress is only approximately one-third of that observed below 0.1 V. This approach can be adapted to help resolve the localized stress in a wide range of electrode materials, to gain additional insights into mechanical effects of charge storage, and for long-lifetime battery design.

Figure 1
Ampero-Coulometry: A New Technique for Understanding Lithium-Sulfur Electrochemistry
Authors: Gulzar Umair , O'Dwyer Colm
Published: July 2022

Despite limited commercial success, lithium sulfur technology (LST) is still far from replacing existing Li-ion technology. One of the main reasons hindering the success of LST is the limited understanding of lithium-sulfur chemistry during electrochemical charging and discharging. Dissolution of sulfur species in electrolyte solution further enhances the complexity of this system. Therefore, a comprehensive understanding of sulfur species and their kinetics during charge/discharge process is paramount for a high-performance lithium-sulfur battery. In this work, we used a chronoamperometric method to rapidly measure the rate capability of sulfur electrodes. The method allows us to interrogate rate performance of sulfur electrode from 0.1C up to 1000C in 26 mins of chronoamperometric measurement. Electrodes prepared with Super-P, carbon fiber and graphene platelets were compared to understand the relationship between electrode kinetics and geometrical porosity. Moreover, the electrical conductivity of sulfur electrodes with different thickness and material composition were compared to understand their dependence on C-rates. Finally, we developed a new technique 'Ampero-Coulometry' which utilizes the experimental results obtained from chronoamperometry and mathematically transform to reveal rate capability of carbon-sulfur electrodes at different state of charge/capacity (Figure 1a, b). This technique allowed us to track the overall rate of reactions inside Li-S cell over a complete state of discharge. For the first time, we were able to correlate Li+ diffusion coefficient with the chronopotentiometric discharge profile of a Li-S battery. As dissolution of sulfur species and their interplay inside a porous sulfur electrode has a significant role in limiting Li-S battery capacity, and we can now relate the known mechanism of polysulfide dissolution with the kinetics of a sulfur electrode and its performance.

Figure 1: (a) Comparison of discharge curve and Ampero-Coulometry curve of lithium-sulfur battery (b) Comparison of discharge curve and differential rate curve of lithium-sulfur battery.

Figure 1