20A01

超過冷却液体シリコンの熱物性測定○岡田純平(宇宙航空研究開発機構 宇宙科学研究所, JST/さきがけ)，石川毅彦，Vijaya Kumar (宇宙航空研究開発機構 宇宙科学研究所)，渡辺勇基（株式会社 エイ･イー･エス）

Thermophysical Properties of Supercooled Liquid Si
Junpei T. OKADA (JAXA/ISAS, JST/PRESTO), Takehiko ISHIKAWA, Vijaya KUMAR (JAXA/ISAS),
Yuki WATANABE（AES Co., LTD）

1. Introduction
Silicon (Si) is a key material which plays an important role insemiconductor technology. As crystalline Si is usually generated
from the melt, the knowledge of its properties in the liquid andundercooled states is of considerable interest. Physicalproperties of liquid Si display many unusual aspects. Upon
melting, Si transforms into a metal accompanied by a density
increased of about 10%. However, the first neighbor atomic
coordination number in liquid (l-) Si remains 5.5–6, which isapproximately half that of simple liquids metals, hinting thatcovalent bonds survive even in the metallic state. In fact,
molecular dynamics simulations of l-Si at 1800K suggest thatapproximately 30% of the bonds are covalent 1). It is remarkablethat two completely different types of bonds –metallic andcovalent- can coexist in l-Si. The coexistence f two forms ofliquid in a single component substance has been predicted toundergo a phase transition as a function of temperature and/orpressure. A recent study reports that l-Si could undergo a liquidliquid phase transition (LLPT) below 1232K, separating into ahigh-density metallic liquid and a low-density semimetallic
liquid 2). But, 1232K is far below the melting temperature of
1683K of Si, and as a result the supercooled state has been
considered inaccessible to current experimental techniques.
A key requirement for the possibility of an LLPT obviously isthat the metallic and covalent bonds coexist in l-Si. Althoughexperimental investigations of the atomic configuration hint at
the existence of covalent bonds in l-Si, surprisingly, soft x-ray
and magnetic susceptibility measurements of electronic
properties so far do not support this viewpoint in that all fourvalence electrons in l-Si appear to behave like free electrons.
Emissivity and thermal conductivity of l-Si also exhibit a freeelectron-like temperature dependence. It is clear that theexistence of the covalent bonds in l-Si has not been established.
We have performed x-ray Compton scattering experiments on
Si using electrostatic levitation technique. An excellent
agreement is found between the measurements and thecorresponding Car-Parrinello molecular dynamics simulations.
The population of covalent bond pairs in l-Si is estimated to be
17% via a maximally localized Wannier function analysis 3). Our
results show persistence of covalent bonding in l-Si and provide
support for the occurrence of theoretically predicted LLPT insupercooled states. To realize the predicted metastable phase,

we have performed electrostatic levitation experiments onsupercooled l-Si.

2. Experiments
Samples were prepared by smashing single crystal wafer Si(99.99999% purity) into small pieces. These pieces were melted
into spheroids with 2mm diameter using a gas levitator under Ar
atmosphere. The spheroid samples, charged by thermoionicemission, were levitated in a high-vacuum environment(approximately 10-5 Pa) using electrostatic forces via a feedback
loop. Two horizontal electrodes, separated by 10 mm, assured
the vertical position control of the sample. This, together withfour spherical electrodes distributed radially at the height of alevitated sample, offered sufficient sample stability to performmeasurements of physical properties. The sample was heatedand melted using the focused radiation of three laser beams withwavelength of 10.6 m generated by CO2 laser. Thisconfiguration minimized sample oscillations and enhanced
temperature uniformity.
The density l-Si was determined using an ultraviolet imaging
technique. The viscosity and surface tension of l-Si were
determined by the oscillation drop technique. In this technique,a P2 cos()-mode drop oscillation was induced to the liquidsample by superimposing a small sinusoidal electric field on thelevitation field. The transient signal that followed thetermination of the excitation field was detected and analyzed.
This was done several times at a given temperature and repeatedfor numerous temperatures.

3. Results
Viscosity and surface tension was measured over thetemperature range from 1400 to 1700K. Density was measured
over the temperature range from 1250 to 1900K. 1250K is very
close to 1232K where theoretically predicted LLPT could occur.
We will discuss in our talk whether the predicted metastablephase could appear in supercooled Si.

References
1)

I. Stich, R. Car, and M. Parrinello, Phys. Rev. Lett. 63,2240 (1989)

2)

P. Ganesh and M. Widom, Phys. Rev. Lett. 102, 075701(2009).

3)

J. T. Okada, P. –L. Sit, et al.,, Phys. Rev. Lett. 108, 067402 (2012).

− J 11 −20A02「きぼう」搭載静電浮遊炉の開発状況○田丸晴香，村上敬司，柴崎浩一，大熊隼人，中村裕広，石川毅彦，岡田純平（JAXA），
高田哲也，新井達也，藤野直樹，山浦由起子（株式会社 IHI エアロスペース)

Status of Development of Electrostatic Levitation Furnace (ELF) for KIBO in ISS
Haruka TAMARU, Keiji MURAKAMI, Kohichi SHIBASAKI, Hayato OHKUMA, Yasuhiro NAKAMURA,
Takehiko ISHIKAWA, Junpei T. OKADA (JAXA), Tetsuya TAKADA, Tatsuya ARAI, Naoki FUJINO,
and Yukiko YAMAURA (IHI Aerospace Co. Ltd)

1. Introduction
JAXA has started the development of Electrostatic Levitation
Furnace (ELF) for Kibo/ISS. The ELF enable us to realize thecontainerless processing in a vacuum/gas, and it leads tomeasurement of thermophysical properties around high melting
temperature, and to quest for new functional materials bysolidification including overcooling conditions. The first targetof ELF for Kibo is the melt oxides. The melt oxides cannot be
levitated by electromagnetic force and also it is difficult by ELF
on ground, because the electric charge of nonconductor is muchless than that of conductor. The ELF will be set into the Multipurpose Small Payload Rack(MSPR) in Kibo. Fig. 1 shows theoverview of ELF.
ELF in MSPR

Sample holder (with samples) will be retrieved by any returnvehicle.
2.2 Specification
Table 1 shows the engineering Specification of ELF.
Table 1Items

ELF main parts
MSPR

Fig. 1

Overview of ELF

Cartridge

Engineering Specification of ELF
Spec.

Sample Size

1-5 mm (main target; 2mm)

Sample Materials

Metals, Alloys, Glasses, Oxides etc.
(Toxic Hazard Level = 0 )Position stability±100 m

Atmosphere

Ar / N2 / N2+Air up to 2 atm low
pressure, 10-3 Torr by waste gas line

Heating

970nm / 4 diode lasers. Total 160 W

Temperature
measurements

Pyrometer (100Hz), 300~3000℃

Magnified Image

higher than 140 pixel / diameter

Cameras

1 for density measurement (withtelephoto lens), 1 for general view

Thermophysicalpropertymeasurements

 density by Image Analysis
 surface tension and viscosity by
Oscillating Droplet Method

3. Status of Development
Now we finished the Engineering Model (EM) Fabrication,
and we are testing the EM of ELF. It was very difficult to set the
EM into the Work Volume of MSPR under various restrictions
including the structure, safety, heat exhausting, and power andso on, but finally we completed the fabrication. Fig. 3 shows theassembled EM, and the Levitation control of sample on the
ground has realized such as Fig. 4.

Door for ELF

Sample Holder
Cartridge

Sample(1-5 mm in dia)Fig. 2 Sample Cartridge Overview

2. Functions and Specification
2.1 Operation concept
We will launch the sample holder with 15 samples in it. Thenthe crew will insert/remove that holder into sample cartridge,
and install that cartridge into ELF which is shown in fig. 2. If
the windows became dirty, the cartridge will be exchanged.

− J 12 −Fig. 3

Assembled EM

Fig. 4 Electrostatic Levitationof EM( 2mm glassy carbon)

20A03

静電浮遊法による高融点金属の粘性測定
渡邊勇基(エイ・イー・エス)、ヴィジャヤ クマール、岡田純平、石川毅彦(宇宙航空研究開発機構 宇宙科学研究所)

Viscosity Measurements of Molten Refractory Metals by Electrostatic Levitation Method
Yuki WATANABE (AES), Vijaya Kumar, Junpei OKADA, Takehiko ISHIKAWA (ISAS, JAXA)

1. Introduction

given by the signal, the viscosity can be determined by:

Thermophysical property of refractory metals is important asparameter of numerical simulation for casting, welding, and soon. It is important to know their thermophysical properties formaterial processing. But there is less or no reliable data due todifficulties of measurement because of their high melting
temperature or high vapor pressure.
In recent years, non-contact techniques for thermophysicalproperties measurements at high temperature with electrostatic
levitators (ESL) have been developed 1-3). Measurements by
ESL technique can prevent chemical reactions between thesample and container walls at high temperature.
We understand that viscosity measurement is affected bycontrol frequency to levitate the sample when it overlaps
resonance frequency of the sample 4). In this study, viscosity
measurements of molten refractory metals (melting temperature;Tm>3000K) with improved method were attempted.

2．Experimental Setup and Procedures
2.1 Electrostatic Levitation Furnace
The measurements were made using an ESL which consistedof a chamber evacuated to a ~10-5 Pa vacuum level before
processing was initiated. The chamber housed a sample charged
by electronic emission and levitated between electrodes via a
feedback loop. The two disk electrodes were used for vertical
position control whereas four spherical electrodes werededicated to horizontal control 5). The positioning control reliedon two sets of orthogonally arranged He-Ne lasers and theassociated position detectors. Specimens were prepared by arc
melting into spheroids with diameters of ca. 2mm.
The sample was heated using two 100W CO2 lasers split into
three beams in a horizontal plane and one 500W YAG laser
straight down on the sample. The radiance temperature wasmeasured with a single-color pyrometer.
2.2 Viscosity measurement
The viscosity was determined by the oscillating drop method
6). In this method, a solid sample was first levitated, rotatedaround 10Hz, heated, melted, and brought to a selected
temperature. Then, a P2(cos)-mode drop oscillation was
induced to the sample by superimposing a small sinusoidal  r02 / 5(1)

3．Results
We measured viscosity of molten refractory metals (Ta, Os, Re,
W) which have over 3000K melting temperature. By way ofsample, it is shown the viscosity data of molten tungsten (W,Tm=3695K) and tantalum (Ta: Tm=3290K) measured including
undercooled state in wide temperature range in Fig.1. It shows
viscosity versus temperature with different control frequency ofthe sample. We were able to measure viscosity of even tungsten(highest Tm in pure metals) in a stable condition due toseparating control frequency for levitating and the resonancefrequency band of the sample.
20

20

W

Ta

15

15

10

10

5

5

240 Hz720 Hz240 Hz720 HzTm

03100 3200 3300 3400 3500 3600 3700 3800 3900

Temperature (K)

Fig.1

Tm

0
2800

3000

3200

3400

3600

Temperature (K)Viscosity of W and Ta versus temperature.

4. Conclusions
The viscosity of molten refractory metals were measured with
an electrostatic levitator and the data were reported over wide
temperature ranges, including the undercooled state.

References
1) Rhim W K et al. Rev. Sci. Instrum 64 (1993), 2961.
2) P.-F. Paradis and W.-K. Rhim, J. Mater. Res.14 (1999), 3713.
3) T. Ishikawa, P.-F. Paradis, T. Itami, S. Yoda, Meas. Sci.
Technol. 16 (2005) 443-451.
4) T. Ishikawa et al. Rev. Sci. Instrum. 80 (2009), 013906..
5) W. -K. Rhim, S. -K. Chung, D. Barber, K.-F. Man, G. Gutt, A.
A. Rulison, and R. E. Spjut; Rev. Sci. Instrum. 64 (1993),
2961.
6) W.-K. Rhim, K. Ohsaka, and P.-F. Paradis; Rev. Sci.Instrum.
70 (1999), 2996.

electric field on the levitation field. Using the decay time − J 13 −20A04

ガス浮遊法による希土類添加アルミナガラスの生成と光学的特性○ヴィジャヤ クマール, 石川毅彦, 岡田純平 (宇宙航空研究開発機構 宇宙科学研究所)，渡辺勇基（株式会社 エイ･イー･エス）栗林一彦 (芝浦工業大学)

Formation and Optical Properties of Rare-earth Aluminates Glass by Aerodynamic
Levitation○Vijaya KUMAR, T. ISHIKAWA, J. T. OKADA (ISAS/JAXA), Y. WATANABE (AES) andK. KURIBAYASHI (SIT)
1. Introduction
Recently, research on bulk glass and glass-ceramics haveattracted the attention of material scientists as they are
considered as low cost optical materials for the future.
Containerless processing enables glass formation of materials
with a low glass forming ability because it prevents
heterogeneous nucleation from the container walls and thus
promotes deep undercooling prior to nucleation from the melt
and helps to produce stable, metastable and glass phases. There
are few reports on the bulk glass formation of R2O3-Al2O3
binary system 1-3) but the required properties were not achieved
for actual use. The La2O3-R2O3-Al2O3 ternary system wasselected in order to fabricate improved properties of new rareearth aluminate glasses. In the present study, the formation of
bulk spherical glasses and their densities, thermal and opticalproperties have been investigated due to their unique features interms of the solidification process from an undercooled melt,
glass structure and optical properties.

The glass transition temperature, thermal stability, density andoptical properties were studied for the newly formed glasses.

3. Results and discussion
Figure 2 shows the differential scanning colorimetry (DSC)
results of the R2O3-Al2O3 glasses. The glass transition
temperature (Tg) gradually increased with increasing ionicradius of the rare-earth elements. Only one crystallization peak
was observed for Nd, where as three crystallization peaks wereidentified in the Sm-glass. These peaks might be due to theformation of metastable phases. The density decreases withincreasing ionic radius and on the other hand the molar volume
increases with an increase in the ionic radius. The Nd2O3-Al2O3
glass showed a high refractive index of ~1.90. These results
clearly suggest that the glass with a smaller ionic radius of R has
a denser packed structure. Our results indicate that containerlesslevitation is an elegant technique for fabrication of new glassand crystalline ceramics from an undercooled melt.
Tg=glass transition temperature
Tx=crystallization temperature

2. Experimental

1223 K

In order to undercool the melt deeply below the melting
temperature, an aerodynamic levitator (ADL) was designed
Endothermic - Exothermic(Fig.1). A spherical sample with a diameter of ~2.5 mm andmass of ~20-25 mg was levitated by an ADL and completely
melted by a CO2 laser. The surface temperature and in-situ
observation of the levitated droplet was monitored using
pyrometer and high speed video camera, respectively. Then thedroplet was cooled to room temperature by cutting off the laser.

Tx =1184 K
Tg=1102 K
NdAlO3

II =1215 K

I =1201 K
III =1249 K

Tg=1106 K

Tx=1182 K

SmAlO3

800

900

1000

1100

1200

1300

Temperature/K
Fig.2 Glass Transition
and Crystallization
temperaturesof the R2O3-Al2O3 glass determined using DSC.

References
1) J.K.R. Weber, J. J. Felton, B.Cho; Nature, 393 (1998) 769.

2) K. Nagashio et al., Mat. Sci.Forum, 329-330 (2000) 173.
3) C.J. Benmore et al ; J. Phys.Condens. Matter, 41(2003)S2413.
Fig.1 Schematic diagram of an Aerodynamic Levitator (ADL)− J 14 −20A05

国際宇宙ステーションでの多元系半導体 InGaSb 結晶成長実験に向けた熱物性測定○阪田薫穂(JAXA)，向井碧 (AES)，Govindasamy Rajesh，Mukannan Arivanandhan (静大) ，
稲富裕光，石川毅彦(JAXA)，早川泰弘 (静大)Thermophysical Property Measurements of InGaSb toward the Experiment of
Semiconductor Crystal Growth Process on ISS
Kaoruho SAKATA (JAXA), Midori MUKAI (AES Co., Ltd.),
Govindasamy RAJESH, Mukannan ARIVANANDHAN (Shizuoka Univ.),
Yuko INATOMI, Takehiko ISHIKAWA (JAXA), Yasuhiro HAYAKAWA (Shizuoka Univ.)

1. Introduction
The multi-component semiconductor materials are expected
to be used for various applications. However, the mechanism of
their crystal growth has still many unknown properties forcontrolling the composition and quality of the crystal, due tosegregation related problems and instability of interface between
grown crystal and the melt. In order to apply the crystal for
device application, it is demanded that the mechanism of crystal
growth is clarified. For the purpose, focusing on InGaSb, which
can be applied for thermo photovoltaic and infrared detector
applications, we are ready to carry out the crystal growthexperiment on International Space Station in near future, named"Alloy semiconductor project" 1). The results of theseexperiments will be compared with numerical modeling. In
order to obtain reliable modeling results, the input parameters
i.e., various thermophysical parameters must be accurate. In thisstudy, viscosity of InGaSb was measured, which is an essential
property for numerical modeling of crystal growth. In addition,
wetting properties between a molten InGaSb and substrates
made of quartz, BN, graphite and C-103, used for ampoules andcartridges of the experiments, were investigated. The
evaporation rate of molten InGaSb was also investigated tocheck the affinity of sample configurations.

2. Experimental
The GaSb, InSb and InxGa1-xSb samples (x=0.2, 0.4, 0.6, 0.8)
were prepared from the 6N purity source materials.
Viscosity was measured with oscillating viscometer (ShinkuRiko, MC980016), and calculated using an approximation
method based on the Roscoe’s equation 2). The measurement
temperature for InxGa1-xSb was set between their melting points
and 1100 ºC. BN was used as a crucible material for its highchemical stability and low wetting property for InGaSb.
Wetting property was measured with the 2×2 mm2 sized
InxGa1-xSb samples in each composition placed on the substratematerial, such as quartz, BN, graphite and C-103 (Fig.1). The
temperature of the sample was first increased up to just above
the melting point in each sample, then the wetting images,
wetting angle, and density of the liquid were obtained bychanging the temperature to 900 ºC and 1100 ºC.

For the measurement of evaporation rate, TGA apparatus(Perkin-Elmer TGA7) was used. The sample temperature was
kept constant for 180 min at every 100 ºC, between 600 and1100 ºC. In order to control the sample environment, theexperiments were performed under Ar atmosphere.

(a)

(b)

Fig. 1The sample with the substrate (a) beforeand (b) after the measurements of wetting property.
experiment
3. Resultsand Discussion
As a result of the measurements, absolute value of viscosityof InSb and GaSb showed good agreement with previous study
in literature, and all the results showed good Arrhenius linearity.
As for InxGa1-xSb, it is indicated that the sample with larger
component of In showed lower viscosity. These results ofviscosity data versus temperature can be applied to thenumerical simulations of crystal growth.
From the investigation of wetting property, it is suggested thatthe wetting ability of InGaSb on C-103 substrate was muchhigher compared with that on the other substrates (quartz, BN
and graphite). The results of BN and graphite having low
wetting ability for InGaSb can prove that they are suitable forthe ampoule material because they affect little to the crystal
growth of InGaSb.
The evaporation rate increased for all the samples by
increasing the temperature. At high temperatures, the difference
between the evaporation rates of the samples was large.

References
1)

M. Arivanandhan, G. Rajesh, A. Tanaka, T. Ozawa, Y. Okano, Y.
Inatomi, Y. Hayakawa, Diffusion and Defect Forum, 323-325(2012) 539.

2)

R. Roscoe, Proc. Phys. Soc, 72 (1958) 576.

Acknowledgements
The authors are grateful to Mr. Y. Momose, Mr. T. Koyama in
Shizuoka University and Mr. K. Murakami in JAXA, for the support ofthe experiments.

− J 15 −20A06

TLZ 法育成 SiGe 結晶大口径化の課題
1

1○木下恭一 ，荒井康智 ，稲富裕光 1，塚田隆夫 2，宮田浩旭 3，田中涼太 3，田口恵祐 3，冨岡 浩 3，
高柳昌弘 1，依田眞一 1(1: 宇宙航空研究開発機構, 2: 東北大学, 3:（株）エイ・イー・エス)

Issues in Increasing Diameter of TLZ-Grown SiGe Crystals
1

K. KINOSHITA , Y. ARAI1, Y. INATOMI1, T. TSUKADA2, H. MIYATA3, R. TANAKA3, K. TAGUCHI3,
H. TOMIOKA3, M. TAKAYANAGI1 and S. YODA1 (1: JAXA, 2: TohokuUniv., 3: AES Co. Ltd)

1. Introduction
We plan homogeneous SiGe crystal growth aboard the ISS
using a gradient heating furnace (GHF). The growth method is a
traveling liquidus-zone (TLZ) method. The TLZ method is akind of zone melting method and is proved to be an excellent
method for growing compositionally homogeneous mixed
crystals such as Si1xGex, In1xGaxAs and so on. For practicaluse of TLZ-grown crystals, increase in crystal diameter isessential. Here, we report issues in increasing crystal diameterof TLZ-grown SiGe crystals.

homogeneity than 10 mm diameter crystals. Convective mixing
effect in a melt might be beneficial to decreasing radial
temperature gradient.
3.3 Cracks
A Si seed is used for growing a Si0.5Ge0.5 crystal. Cracks due
to lattice mismatch between a seed and a grown crystal, and thatbetween a solidified melt and a feed are inevitable. In addition,
cracks due to thermal stress during cooling process after crystal
growth increase with increasing crystal diameter. Elimination of
cracks may be a critical problem for applying Si0.5Ge0.5 crystals
to electronic devices.

2. Experiments
Si0.5Ge0.5 crystals were grown by the TLZ method. Crystal
diameter were 2, 10, 30 and 50 mm and growth lengths were
between 3 and 25 mm. Temperature gradients between 7 and25℃/cm were applied and growth rates were 0.1 to 0.4 mm/h.
Grown crystals were checked by outer shape observation andwere characterized by an electron probe microanalyzer (EPMA)
and an electron backscattering pattern (EBSP) on polishedsurfaces.

4. Summary
Some issues in increasing Si0.5Ge0.5 crystal diameter isdiscussed. Microgravity experiments will give a hint to solve
some of these issues because convective mixing in a melt isrelated to some of the issues. The critical problem might becracks due to lattice mismatch and due to thermal stress.
Intensive study is needed for suppressing cracks for applying
Si0.5Ge0.5 crystals as substrates for electronic devices.

3. Issues in Increasing Crystal Diameter
Some issues in increasing crystal diameter were found in thecourse of characterization of various diameter crystals. They arelisted below.
3.1 Single Crystal Length Limitation
For 2 mm diameter crystals, 25 mm long Si0.5Ge0.5 single
crystals were grown1). However, single crystal length decreased
to about 5 mm for 10 mm diameter crystals2,3) as shown in Fig. 1. This
is interpreted that increased convective mixing in a melt caused
deeper constitutional supercooling and it resulted inpolycrystallization. This hypothesis will be proven by
microgravity experiments because convection in a melt is
suppressed in microgravity.
3.2 Radial Compositional Variation
In large diameter crystals, radial compositional variation ispredicted to be increased by radial temperature gradient4). For
decreasing radial temperature gradient, thermal conduction
control in a sample cell is important. We found that 30 and 50
mm diameter crystals have rather better radial compositional

Fig. 1

Crystal orientation analyzed by an EBSP for a
10 mm diameter Si0.5Ge0.5 crystal.

References
1)
2)
3)
4)

− J 16 −H. Miyata et al., J. Crystal Growth, 303 (2007) 607.
K. Kinoshita et al., Thin Solid Films, 520 (2012) 3279.
K. Kinoshita et al., J. Crystal Growth, 349 (2012) 50.
S. Adachi et al., J. Crystal Growth, 334 (2011) 67.

20A07“きぼう”より送られてきているリゾチーム結晶成長“その場”測定データ：
地上と何が違うか
塚本勝男，忍健太郎，山崎智也，三浦均（東北大），吉崎泉（JAXA），福山誠二郎（エーイーエス），
島岡太郎（JSF），真木孝雄（オリンパス（株）），橘勝（横浜市大），鈴木良尚（徳島大）Live Growth Rate Measurement from Lysozyme Crystals Growing in KIBO
Katsuo Tsukamoto1, Kentaro Oshi1, Tomoya Yamazaki1, Hitoshi Miura1, Izumi Yoshizaki2, Seijirou Fukuyama3,
Taro Shimaoka4, Takao Maki5, Masaru Tachibana6, Yoshinao Suzuki7
1

Grad. School of Science, Tohoku University, Sendai, Japan, 2JAXA, Tsukuba, Japan, 3Advanced Engineering
6Services Co.,Ltd. (AES), 4Japan Space Forum (JSF), Tokyo, Japan, 5Olympus Co., Tokyo, Japan, Yokohama

City University, 7 Tokushima University

We have successfully been receiving growth rate of lysozyme
crystals from “Kibo” at International Space Station (ISS) by insitu interferometry since the beginning of August 2012, so as toget the growth rate of lysozyme crystals vs supersaturation in an
ultra-pure andnormalsolutions with different protein

concentrations. This experiment will continue for the coming
five months.
Although so many space grown crystals have been obtainedso far, no attempt has been done to measure the growth rate
because of two reasons; (1) technical difficulties to measure theFig. 1 A live interferogram from a
growing lysozyme crystal in KIBO,
Michelson Interferogram, to measure thegrowth rate of crystal with the accuracyof 0.001nm/s.

growth rate vs supersaturation in space and (2) the growth rate
has been believed to be much lower than the rate under gravity
due to the absence of convection and flow. However Tsukamoto
et al. (2007) found the increase of growth rate of lysozyme

In the talk, we will review the preliminary results of growth
crystals by ex-situ measurement in a Foton- M3 recovery
rate vs supersaturation after the review the experimental set-up
satellite in a specific range of supersaturation.
and finally discuss why the growth rate increased and it is
The present experiment is another approach to measure therelated to the perfection of crystals.

growth rate in situ in the order of 0.01nm/s by interferometry,Fig.1, in “Kibo” in order to understand the reason why thegrowth rate is increased in space. In order to perform thisexperiment, every parts of “in situ” observation systems has
extensively been renewed to be miniaturized and simplified witha new concept.

− J 17 −20A08溶液より成長している結晶周囲の三次元濃度場測定○村山健太，塚本勝男，三浦均，Atul Srivastava (東北大学)，真木孝雄（オリンパス株式会社）

3-D Measurement of the Concentration Field Around Growing Crystal in the Solution
Kenta MURAYAMA, Katsuo TSUKAMOTO , Hitoshi MIURA, Atul SRIVASTAVA (Tohoku Univ.),
Takao MAKI (Olympus Co., Ltd.)
1. Introduction
It is known that the crystal growth mechanism in the solutionchanges as the supersaturation increases 1). When the crystal is
growing in the supersaturating solution, the solute concentration
at the interface is smaller than that of the bulk solution because
the crystal grows by incorporating solute in a solution 2).
There have been many reports concerning the measurementof the concentration field, but many of them were twodimensional (2-D) observations, namely, the objects wereobserved only from one direction 2). The information obtainedby the 2-D observations is integrated along the direction of theobservation, so the local information, e.g., concentration
distribution around the crystal-liquid interface, was not obtained.

2. 3-D observations
To improve the disadvantage on the 2-D observation, amethod of computer tomography (CT) has been adopted bysome authors. By using the CT method, one can reconstruct the
information of the three-dimensional (3-D) concentration fieldaround the growing crystal based on 2-D observations obtained
from several directions (3-D observation) 3).
Srivastava et al. (2010) carried out a 3-D observation of theconcentration field around sodium chlorate using Mach–
Zehnder interferometer and octagonal crystal growth cell. The
octagonal cell enables us to obtain interferograms in four
different directions (0, 45, 90, 135 degree) 4).
However, the spatial resolution in tomography will be
improved by increasing the number of the observation
directions. It is necessary to discuss whether the observationfrom four angles is enough for measuring the concentration fieldor not, so the observation from more directions is desirable.

Fig.1 Principle of refractive index matching
4. Results and discussions
We observed the concentration field around sodium chlorate(NaClO3) crystal growing in the solution. The supersaturation
was adjusted atσ=0.0335 in bulk. The observation was carriedout at intervals of 22.5 degrees. Fig.2 shows the comparison of
the interferograms in the case of only the cylindrical cell (a) andthe refractive index matching cell (b). In Fig.2 (a), the obtainedinterference fringes were not suitable for determining theconcentration distribution because of the refraction of the lightand the influence of aberration by the lens effect at the cell wall.
In Fig.2 (b), we obtained the interference fringes at equalinterval at the bulk solution, which enable us to determine theconcentration field. These results suggested that the matchingliquid removed the bending of the light beam properly. By using
the cylindrical growth cell with the refractive index matching
method, the observation from arbitrary angles became possible.
The number of the observation directions can be increasedby using the refractive matching cell. It is expected to improve
the spatial resolution of 3-D observation of a concentration field.

3. Refractive index matching cell
To obtain 2-D images in many directions, we prepared acylindrical growth cell. Usually, it is considered that thecylindrical cell is not suitable for the interferometer because thecurved wall of the cell bends the light beam. We will overcome
this problem by using the refractive index matching method 5).
To avoid the bending of the light beam, we put the matchingliquid whose refractive index is close to that of the glass aroundthe cylindrical cell. This liquid removes refraction and reflectionof the light at the wall of the cylindrical cell, so the beam canpass through the cell straightly (Fig.1).

Fig. 2 Interferograms of the concentration field around NaClO3
crystal (a) Cylindrical cell in the raw(b) Refractive index
matching cell

References
1)
2)

3)
4)
5)

− J 18 −Ichiro Sunagawa. Kyoritsu publishing, 2003.
Shigenao Maruyama, Toshiyuki Shibata, Katsuo Tsukamoto andKenji Shimizu: Heat Transfer-Japanese Research, 27 (2) (1998)
114
F. Bedarida: J. Crystal Growth, 79 (1986) 43
Atul Srivastava, Katsuo Tsukamoto, E. Yokoyama, K. Murayama,
M. Fukuyama: J. Crystal Growth, 312 (2010) 2254
Hiroyuki Suhara, Satoru Itoh, Takeshi Ueda and Tatsuya Ito:
Ricoh Technical Report, 25 (1999) 120

20A09タンパク質結晶化容器 JAXA Crystallization Box (JCB)の改良○田仲広明，厳 斌（（株）コンフォーカルサイエンス CS）, 古林直樹（（株）丸和栄養食品 MF）,
高橋幸子（CS）, 正木美佳（（独）宇宙航空研究開発機構 JAXA），伊中浩治（MF），太田和敬，
小林智之，三好寛、吉村善範（JAXA）

Upgrade Version of JAXA Crystallization Box (JCB) for Protein Crystal Growth in Space
Hiroaki TANAKA, Bin YAN (CS), Naoki FURUBAYASHI (MF), Sachiko TAKAHASHI (CS), Mika MASAKI (JAXA)，
Koji INAKA (MF), Kazunori OHTA, Tomoyuki KOBAYASHI, Hiroshi MIYOSHI, Yoshinori YOSHIMURA (JAXA)

1. Introduction
JAXA Crystallization Box High Density (JCB-HD) has been
the main crystallization device in JAXA High-quality
Crystallization Project since 2007. JCB-HD is a cell with highdensity integration, using the counter-diffusion method.
However, it has some points to be improved such as nonnegligible water permeability, smaller volume of precipitantsolution cells, and rather complicated assembly. To solve thesepoints, we are now developing a new cell, JAXA Crystallization
Box (JCB)-SGT.

1. Pour precipitant solution

2. Insert capillary with a gel-tube

3. Place two capillaries in one cell

4. Remove air from the cells, and seal the

2. New Crystallization Device
2.1 JCB-SGT
The outlook of JCB-SGT is shown in Fig. 1. JCB-SGT is
made of very low water-permeable material, Techbarrier-HX(PET+SiOx coating). Therefore water permeability of thecrystallization cell which may cause air bubbles in the
precipitant cell will not disturb crystallization in JCB-SGT.
JCB-SGT can contain much larger volume of precipitantsolution in one cell (1200 micro-L) if compared to JCB-HD(180 micro-L). Therefore, the amount of the precipitant solution
in JCB-SGT is large enough not to worry about the dilution of
the precipitant solution with protein solution during the
crystallization experiment.

three cells together with sealing machine

Fig. 2

The assembly of JCB-SGT

Fig. 1 Outlook of JCB-SGT
The preparation of JCB-SGT is shown in the Fig. 2. There arethree thin and long cells in one SGT Crystallization Unit. The
cell is filled with precipitant solution. The capillary filled withprotein solution is plugged with “gel-tube” and inserted in thecell. The capillary is 40 mm in length and 0.5 mm in diameter.
The end of the capillary is sealed with clay and the other end
with an agarose gel in the “gel-tube”. Two capillaries can beinserted in one cell. Then three cells are sealed together withsealing machine. JCB-SGT is composed of two SGT
Crystallization Units (12 capillaries), which means thevolumetric efficiency is the same as JCB-HD. The lysozyme
crystal grown in JCB-SGT is shown in Fig. 3a.
2.2 JCB-SLC
JCB-SLC is a device for growing larger crystal. The

Fig. 3 Crystals grown in (a) JCB-SGT and (b) JCB-SLC
crystallization cell is the same as JCB-SGT. Instead of thecapillary of 40 mm in length, shorter capillary of 35 mm inlength with larger bore of 1.9 mm is used. The preparation of
JCB-SLC is as the same as JCB-SGT except one capillary in
one cell. After insertion, three cells are sealed together withsealing machine. JCB-SLC is composed of two SLC
Crystallization Units (6 capillaries). The assembly of JCB-SLC
is easier than that of JCB-MC (former type of crystallization cellfor larger crystal). The large lysozyme crystal grown in JCBSLC is shown in Fig. 3b.
These new crystallization devices will be in use in JAXA
PCG#6, 2013 (TBD).

− J 19 −20A10ダストプラズマにおける粒子温度計測○足立 聡 (宇宙航空研究開発機構 (JAXA) )，東辻浩夫 (JAXA，岡山大学)，
高橋和生 (京都工芸繊維大学)

Particle Temperature Measurement in Complex Plasmas
Satoshi ADACHI (Japan Aerospace Exploration Agency (JAXA) ), Hiroo TOTSUJI (JAXA and Okayama Univ.),
Kazuo TAKAHASHI (Kyoto Institute of Technology)

1. Introduction
Particle temperature, being equivalent to average kinetic
energy, in complex plasmas is usually estimated from thevelocity distribution function (VDF). To obtain the VDF is noteasy in many cases since the statistical reliability is required. To
satisfy the reliability, the large number of particles must be
observed. This corresponds to the large observation area byusing a small magnification lens. However, the larger area
makes the worse velocity resolution. This means that it is moredifficult to recognize the correct profile of the VDF. Hence, weinvestigated a new method of measuring the particle
temperature based on the pair distribution function (PDF).

2. Theory and Results
The PDF for the complex plasmas is described as,(1)

where h, k and ℓ are the Miller indices, x, y and z are thecoordinates in the unit cell,is the mean squaredisplacement (MSD). The exponential function having the MSD
is called the temperature factor or Debye-Waller factor,
representing the temperature influence on the PDF. This meansthat the temperature is basically estimated from the PDF. If thedisplacement
is expressed by a normal distribution and

Fig. 1

particle oscillations are approximated to be harmonic
oscillations, the temperature in two-dimensional cases like thecomplex plasmas on the ground should be described 1) as
,

(2)

where
represents the oscillation frequency.
The oscillation frequencies are obtained by tracing particle
motions and calculating the Fourier spectra of the time
evolutions of the particle coordinates. The typical result isshown in Fig. 1. From the figure, it is found that thefundamental frequencies are 0.64 and 0.88 Hz and the second
harmonics are 1.29 and 1.64 Hz. Thus the temperature isestimated to be 0.29 eV, which is reasonable value as comparedwith the temperature from the velocity distribution function
method.
The two fundamental frequencies may suggest anisotropy
though the complex plasmas are considered to be an almost
ideal isotropic system. Therefore, further investigation is needed
to understand the particle oscillations. One possibility causing
the anisotropic oscillation may be the defects. To investigate thedefects, we trace the dislocation as the first step. Figure 2 shows
the typical result of the dislocation detection. It is clearlyobserved that the dislocations move around and lattice
distortions relax over time.

References
1)

Typical result of oscillation frequencies

S. Adachi, H. Totsuji, K. Takahashi, Y. Hayashi and M.
Takayanagi: J. Phys.: Conf. Ser., 327 (2011) 012043.

Fig. 2− J 20 −Typical result of dislocation detection

20A11

ISS/JEM 内の微小重力環境○石川巨樹 (株式会社エイ・イー・エス)，柴崎浩一，大熊隼人 (宇宙航空研究開発機構)

Microgravity Environment in ISS/JEM
Naoki ISHIKAWA1, Kohichi SHIBASAKI2, Hayato OHKUMA2
1. Advanced Engineering Services, Co., Ltd. 2. Japan Aerospace Exploration Agency

1. Introduction
In the International Space Station (ISS) / JapaneseExperiment Module (JEM), various kinds of experiments havebeen performed using a microgravity environment. However,this microgravity environment is disturbed due to the vibration
which occurred by crew activity, experimental equipments anddocking of vehicles, etc 1, 2). Thus we have been measured
microgravity environment in JEM by Microgravity
Measurement Apparatus (MMA) and investigated amplitude andsources of vibration for user by analyzing measured data.
In this investigation, we show the characteristic of
disturbance. And we approach analysis of the time dependenceof disturbance in JEM in order to inform user of microgravity
environment in JEM.

frequencies (1, 20 and 100 Hz). Here, points of data in Fig. 2
are calculated by 1/3 octave band analysis per an hour, so
absolute value of acceleration is unconsidered.
According to Fig. 2, it is discern that fluctuation of 1 Hz
acceleration is larger than the others. Because disturbance at 1
Hz is caused by crew activity, so acceleration is decreased
during crew sleep. On the other hand, high frequencies (20 and
100 Hz) are not decreased through 1 day. This is because thesource of vibration is in the apparatus which is always working.

2. Microgravity Measurement Apparatus (MMA)The MMA is consists of following four devices:
TAA (Tri-axial Accelerometer Assembly)
RSU (Remote Sensor Unit)
NCU (Network Control Unit)
MLT (MMA Laptop Terminal)
TAA is located on the surface of SAIBO, RYUTAI and
KOBAIRO racks in JEM. Overview of the MMA configurationin JEM is shown in Fig. 1. Mainly, we use the MMA of
RYUTAI Rack for measurement of microgravity. Data shown insection 3 is also measured here.

Fig. 2 Relations between time and acceleration

4. Conclusion
We showed relation between time and acceleration in one day.
Hence we will analyze in detail more data to indicate thegeneral microgravity environment in JEM from a statisticalpoint of view. Moreover, we will examine the variation of
disturbance in the long term.

References

Fig. 1 Overview of the MMA

1)

M. Goto, K. Murakami, H. Ohkuma: J. Micro. Soc. Vol.28 No.1
(2011) 8.

2)

H. Ohkuma, K. Murakami, M. Goto: J. Micro. Soc. Vol.28 No.1
(2011) 13.

3. MMA Data Analysis
We show the analyzed data taken by one day in Fig. 2. It
shows relations between time and acceleration of three− J 21 −21A01

大気球を利用した液滴列の微小重力燃焼実験
石川毅彦，○菊池政雄（JAXA），山本信（㈱IHI エスキューブ），澤井秀次郎，丸祐介，橋本樹明，
坂井真一郎，坂東信尚，清水成人，小林弘明，吉光徹雄，菅勇志，田崎彩（JAXA），
福山誠二郎（㈱AES），岡田純平，依田眞一，福家英之，梯友哉（JAXA）

Droplet Array Combustion Experiment in Microgravity by Using Balloon Operated Vehicle
Takehiko ISHIKAWA, Masao KIKUCHI (JAXA), Shin YAMAMOTO (IHI Scube Co., Ltd.), Shujiro SAWAI,
Yusuke MARU, Tatsuaki HASHIMOTO, Shinichiro SAKAI, Nobutaka BANDO, Shigehito SHIMIZU, Hiroaki
KOBAYASHI, Tetsuo YOSHIMITSU, Yuuji KAN, Aya TAZAKI (JAXA), Seijiro FUKUYAMA (AES Co., Ltd.),
Junpei OKADA, Shinichi YODA, Hideyuki FUKE, Yuya KAKEHASHI (JAXA)

1. Introduction

for the experiment. Appearance of the modified DCU EM is

Droplet array combustion experiment in microgravity
environment, provided by the balloon operated vehicle, hasbeen prepared by the authors. In this paper, overview of theexperiment and the latest status are reported.

shown in Fig. 2.
Linear Slider

2. Overview of the Experiment
2.1 Objectives
Primary objective of the experiment is demonstration andverification of the modified experimental system by the balloon
operated vehicle, described in 2.2, for microgravity experimentsin the future. Secondary objective of the experiment isacquisition of experimental data on fuel droplet array
combustion in microgravity. Kikuchi et al., have performed
study on flame spread mechanism along linear fuel droplet arrayin microgravity by using drop shaft, parabolic flight, andsounding rocket. In recent sounding rocket experiment by
TEXUS rocket, the effects of partial pre-vaporization ofdroplets on flame spread and combustion characteristics were
examined 1). However, there is lack of experimental data withmedium degree of pre-vaporization, though data with small andlarge degree of pre-vaporization were successfully obtained by
the drop shaft experiments and by the sounding rocket
experiment, respectively. Therefore, acquisition of experimental
data with medium degree of pre-vaporization is intended by thecurrent experiment by the balloon operated vehicle.
2.2 Experimental System
The experimental system is based on that used in previous
missions 2). However, it was vigorously modified this time sothat it could accommodate much larger payload in the main
body, compared with previous missions. Also, drag-free control
method for the payload was changed from previous 3-axis
method to 1-axis method, as shown in Fig. 1. Engineeringmodel (EM) of the droplet array combustion experiment unit
(DCU) for the previously mentioned TEXUS rocket experimentis employed as the payload in the current experiment. Somemodifications of the DCU EM (e.g. Replacement of high-speed
video camera, Addition of electric batteries, etc.) was performed(a) Previous Type (b) Type A(c) Type B (current type)
3D control
No drag-free control 1D control
Small payload
Large payload
Relatively large payload

Fig. 1

Drag-free control method of the payload

Fig. 2 Appearance of the DCU EM
3. Latest Status of the Experiment
Development of the whole experimental system wascompleted by the summer of 2012. Final preparation of theexperiment was also performed in the experimental site (Taiki
town, Hokkaido) from mid. August, 2012. Unfortunately,
however, execution of the flight experiment in this season wascancelled, due to undesirable wind condition in the high altitude.

References1)2)− J 22 −M. Kikuchi, et al., Proc. 49th Combustion Symposium (Japanese),
pp.108-109, 2011.
S. Sawai, et al., J. Jpn. Soc. Microgravity Appl., 26 (2009)21-28.

21A02

微小重力場における電線被覆の過電流連続通電による着火限界○重田尚樹，伊東弘行，藤田修（北海道大学大学院）

Ignition Limit of Electric Wire Insulation with Continuous Excess Current in Microgravity
Naoki SHIGETA, Hiroyuki ITO, Osamu FUJITA (Hokkaido Univ.)

1. Introduction

obtained by a drop tower and in 1g are from the previous work 2).
Ignition delay time increases when applied power was decreased.

Overloading of an electric wire is a cause of fire in space craft.
Wire ignition by overloading is more probable in microgravity

The ignition limit also decreases as g time increases. Fig.3(g) than normal gravity (1g) according to previous works.

shows a comparison of minimum ignition energy, defined as

Therefore, it is important to know the ignition characteristics of

total energy for ignition, between 1g and g. This energy in goverloaded wires in g.

is lower than in 1g. And in g, despite ignition delay time being

The ignition limit is defined as the lowest applied power atwhich ignition can occur. According to the previous research,
the ignition limit decreases when microgravity time is increased
2). So it is important to know the real ignition limit in long term

greatly changed the energy changes not significantly. It implies
that the wire ignites if a given Joule energy is supplied to the1,2)wire in g, which is smaller than that in 1g.
Ignition delay time [s]g environment. In the present work, therefore, the effect of gtime on this limit is investigated by parabolic flight experiments.

2. Experimental

SampleControler

Ignition limit in 20s μＧ
Ignition limit in 4.5s μＧ
Ignition limit in 2.5s μＧ
Ignition limit in 1Ｇ

0

5

10

15

20

25

Fig.2 Ignition delay time (DAS:O2=19-21%, Others: O2=21%)
Applied power [W/cm] (1Ｇ)
10
18
16
14
12
10
8
6
4
2
0 0

15

20

25

DAS (20s μＧ)
MGLAB (4.5s μＧ)
COSMOTORRE (2.5s μＧ)
Ground (1G)
5

10

15

Applied power [W/cm] (μG)

Fig.3 The difference in minimum ignition energy
between 1g and g (DAS:O2=19-21%, Others: O2=21%)

4. Conclusions
In g, the ignition limit decreases when g time increases.
However, in any g time, minimum ignition energy is not

Combustion chamber
DV camera

10.00
16.00

Power source

Ignition (20s μＧ, DAS)
Ignition (4.5s μＧ, MGLAB)
Ignition (2.5s μＧ, COSMOTORRE)
Ignition (1G, Ground)

Applied power [W/cm]

Minimum ignition energy [J/cm]

The experimental system is shown in Fig.1. This system
consists of the combustion chamber, the sample holder withsample wire, the power source, the programmable controller,
and a digital video camera (30 fps). The combustion chamber is
air tight structure, in which wire ignition takes place. A series ofseveral experiments are held without gas displacement, so
absorber of combustion products, CO2 and H2O, is set in thechamber. Initial O2 concentration is 21%, and balance gas N2,
total pressure 100kPa. Sample wire is a nickel-chrome core wire
coated with polyethylene insulation, because it is easy to control
the value of the Joule energy given for the wire. The diametersof the wire and inner core are 0.8 and 0.5 mm, respectively. The
electric current is a main test parameter, which is kept constantfor the period of a parabolic flight test. Microgravity
experiments were held at Diamond Air Service (DAS) in
Komaki, Aichi. The available microgravity time by a parabolic
flight is around 20s.

16
14
12
10
8
6
4
2
0

significantly changed. It means that a minimum amount of Jouleenergy is required for ignition, which can be called as minimum
ignition energy for wire insulation.

Sample holder

Fig.1 Experimental setup.

3. Results and discussion

References

Fig.2 shows relationship between ignition delay time, definedas the time after the start of the current supply until the momentof ignition, and applied power per unit length, which iscomputed by multiplying square current by resistance. The data

1) R. Friedman, Fire Safety in Spacecraft, FIRE AND MATERIALS,
20(1996) , 2352)− J 23 −K.Agata, Y.Ichimura, T.Fujii, H.Ito, Y.Naokamura, O.Fujita ., 45th
Japanese combustion symposium(2007), 468

21A03

赤外吸収法を用いた燃料液滴近傍の蒸気濃度計測○福山誠二郎((株)エイ・イーエス)，菊池政雄(JAXA)，山本信 ((株)IHI エスキューブ)

Study on Fuel Vapor Concentration Measurement near Fuel Droplet Surface
by Infrared Laser Absorption Method
Seijiro Fukuyama (AES Co., Ltd.), Masao Kikuchi (JAXA), Shin Yamamoto (IHI Scube Co., Ltd.)

1. Introduction
It is essential to consider the influence of pre-vaporized fuelvapor layer around fuel droplets on flame spread between
droplets, from the viewpoint of flame spread in spraycombustion for low volatility fuel in high-temperature
atomsphere, such as internal combustion engine. Investigations
on fuel droplet-array combustion have been conducted by
microgravity experiments for research on essential mechanismof spray combustion 1). In this study, measurement of fuel vapor
concentration near the surface of fuel droplet was performed byusing the infrared laser absorption method 2).

2. Experimental
2.1 Principle of method
The Basic principle of the infrared laser absorption method isexpressed as

 I 

log 
 I    c L
 0 

(1)

where I0 and I are intensity of incident light and transmitted
light, εis molar absorption coefficient, c is mol concentration,and L is optical path length, respectively. The equation (1) iscalled the Lambert-Beer Law. Hydrocarbon molecules such as
n-decane have characteristic absorption wavelength at 3.39 µm,
which is based on stretching vibration of the C-H band.
2.2 Experimental set-up
Schematic of the experimental set-up is shown in Fig.1. HeNe laser with 3.392 µm (NEOARK, NEO-30R3) is employed as
infrared light source in this study. Laser beam is condensed by acondenser lens into the diameter of tens of micrometers at a
focal point. The light which passes near n-decane droplet
surface is led to a bandpass filter and detected by an IR detector.
Detected data is collected with a data recorder.

Op tic a l
Ch o p p e r

In fra re d
H e -N e La s e r
3.39 μ m

Co n d e n s e ｒ
Le n s

B .P .
filte r3. Experimental
3.1 Preliminary Experiment
Prior to the measurement of fuel vapor concentration around
fuel droplet, ε shall be decided. For that, saturated vapor
condition at different ambient temperatures was employed.
Since c (equivalence ratio) and L are known at the saturated
temperature, εcan be decided through measurement of the(I / I0) and the averaged value of ε= 8.7 x 10-3 (1 /φ･mm) was
employed for the measurement of n-decane fuel vapor
concentration.
3.2 Principal Experiment
The measurement results, on the amount of laser absorption
near droplet surface for different ambient temperatures with ndecane, indicate that the intensity of the transmitted laser
decreases with approach to the droplet surface for increase offuel vapor concentration. Also, it is seen that the amount of laser
absorption at a specific distance from the droplet surface
increases with ambient temperature. It could be attributed to thedevelopment of fuel vapor layer around the droplet withincrease of ambient temperature. It was shown that infraredlaser absorption method could be applied to measurement of
distribution of fuel vapor concentration around fuel droplets byscanning the laser path.

4. Summary
These experiments revealed that infrared laser absorption
method could be applied to measurement of distribution of fuelvapor concentration around fuel droplets.
Furthermore, from the viewpoint of comparison 1g and µg,
the similar principle of infrared laser absorption measurements
were performed for 2.5 s microgravity experimental facility(COSMOTORRE) located in Hokkaido, Japan. Unfortunately,
for large noise were observed, it could not be obtained thereliable results.

References
ND
F ilte r

Ve s s e l &F u e l d ro p le t

P bS ed e te c to r

D a taR e c o rd er

Fig. 1 Schematic of experimental set-up.

1)

Kikuchi et al., 6th Asia-Pacific Conference on Combustion 639642 (2007).

2)

Edwards, B. et al., J. Opt. Soc. Am., Vol.55, No.2, 174-177 (1965).

− J 24 −21A04

ISS「きぼう」における固体材料燃焼実験（Solid Combustion）○田﨑彩，菊池政雄，高柳昌弘（JAXA），藤田修（北海道大学），高橋周平（岐阜大学），伊藤昭彦，鳥飼宏之（弘前大学）

Overview of “Solid Combustion” experiment in the ISS/KIBO
Aya TAZAKI, Masao KIKUCHI, Masahiro TAKAYANAGI (JAXA),Osamu FUJITA (Hokkaido Univ.),
Shuhei TAKAHASHI (Gifu Univ.), Akihiko ITO, Hiroyuki TORIKAI (Hirosaki Univ.)
recent status of the Solid Combustion experiment.

1. Itroduction
A lot of astronauts have been staying in spaceship or theInternational Space Station(ISS) for long term and we have been
carring out many scientific experiments in the microgravity
environment. Therefore, it is important issue to protect
astronauts from fire in the microgravity environment. However
the current material flammability tests for fire safety in space are
attained in normal gravity, and it is known that the material
flammability could be higher in microgravity in someconditions[1]-[4]. Thus it is necessasry to understand the impactof gravity presence on material flammability.

2. Overview of the Experiment
2.1 Objectives“Quantitative Description of Gravity Impact on Solid
Material Flammability as a base of Fire Safety in Space(Solid
Combustion)” is one of the candidate experiments of JapaneseExperiment Module/KIBO in the ISS. The Solid Combustion
experiment is planned to conduct using the Multi-purpose Small
Payload Rack(MSPR). In the present research, three types ofsolid material, polyethylene insulated wires, flat plastic sheets
and filter papers are selected as test samples and theirflammability regarding two fundamental processes of solid
combustion, that is, (1)solid material ignition, and (2)flame
spread over solid material, will be quantitatively determined in
microgravity. Then, the discussion on the discrepancy between
the data in normal and micro gravity will be made to give thevalidity of the current material flammability tests.

Fig.1 Ignition map of overloaded wire
Region1:Ignition limit in 1g.
Region2:Ignition limit in short-term g tests.
Region3:Ignition limit in long-term g tests.
Region4:Ignition but no sustained flame.

2.2 Map of ignition and flammability
Fig.1 shows a conceptual description of ignition map ofoverloaded polyethylene insulated wire in terms of O2
concentration and electric current. It is already known that theignition limit is extended in microgravity. Fig.2 conceptuallydescribes the condition where spreading flame is sustained. The
extinction limit(LOI) will be extended in microgravity. But it isdifficult to complete ignition map and flammability map and to
determine the actual limit without long-term microgravity
experiments.
2.3 Status of the Experiment
We are developing a combustion device which enables
experiments for the above mentioned three material types. It is
possible to change oxygen concentration, electric current and air
flow velocity by the device. Here, we provide an overview of

Fig.2 Flammability map of spreading flame
LOI : Low oxygen index minimum O2 concentration to sustain flame
spreading.

References
1) K. Agata, et al., J. Jpn. Soc. Microgravity Appl., Vol.25 No.1, pp.
11-16, 2008.1.
2) O. Fujita, J. Jpn. Soc. Microgravity Appl., Vol.28 , No.3, pp. 90-95,
2011.
3) Y. Onishi, et al., Transactions of the Japan Society for
Aeronautical and Space Sciences, Vol.8, pp.Ph_19-Ph_24, 2010.
4) O. Fujita, et al., Proc.Combustion Institute, Vol.33, Issue2,
pp.2617-2623, 2011.

− J 25 −21A05微小重力下での超臨界二酸化炭素中における不斉光反応
西山靖浩 (奈良先端科学技術大学院大学)，夏井坂誠 (宇宙航空研究開発機構)，辻井薫 (北海道大学)，
垣内喜代三(奈良先端科学技術大学院大学)，出口茂 (海洋研究開発機構), ○井上佳久(大阪大学)

Effects of Microgravity on Chiral Photoreaction in Supercritical Carbon Dioxide
Yasuhiro NISHIYAMA (Nara Institute of Science and Technology), Makoto NATSUISAKA (Japan Aerospace Exploration
Agency), Kaoru TSUJII (Hokkaido Univ.), Kiyomi KAKIUCHI (Nara Institute of Science and Technology), Shigeru
DEGUCHI (Japan Agency for Marine-Earth Science and Technology), Yoshihisa INOUE (Osaka University)

1. Introduction
Chiral photochemistry, which allows us to produce optically
active compounds through electronically excited state, becomes
more popular in recent years as an alternative to the thermal
asymmetric syntheses that employ conventional ground-statechemistry. Of several chiral photochemical strategies, theenantiodifferentiating photosensitization, using only a catalytic
amount of chiral sensitizer, is particularly attractive from theviewpoint of chiral-source efficiency.
We investigated the enantiodifferentiating photoisomerizationof (Z)-cyclooctene (1Z) sensitized by pyromellitates (Pyro) with
optically active menthyl (Men), 8-phenylmenthyl (8Ph-Men)and diacetone fructose (DAF) auxiliaries (Fig. 1) in organic
solvents to reveal that the enantiomeric excess (ee) of chiralphotoproduct, (E)-cyclooctene (1E), is a linear function ofpressure (at least from 0.1 to 400 MPa).1

Fig. 1 Enantiodifferentiating photoisomerization of (Z)-cyclooctene (1Z) sensitized by pyromellitates (Pyro).
Interestingly, the ee of 1E obtained was not linear to pressure
but showed a sudden leap near the critical density when thephotosensitization was run in near- and supercritical carbon
dioxide (nc/scCO2).2 The unique photobehavior in nc/scCO2
was related to the change in CO2 clustering around the excitedstate complex of substrate with sensitizer and therefore affectedby the density fluctuation of nc/scCO2 media. This observation
prompted us to examine the effect of microgravity (g) on thechiral photoreaction in nc/scCO2, where the clustering behavior
is expected to be varied under g.

for performing photoreaction under g in a parabolic flight (Fig. 2);
see the related abstract by Natsuisaka et al. for detail.

Fig. 2 The system developed for the photoreaction under g.Fig. 3 Pressure
dependence ofthe ee of 1E
obtained in thephotoisomerization of 1Z sensitized by DAFPyro in nc/scCO2 at 45 ºC
under normal(●) and g (□)
conditions.

The enantiodifferentiating photoisomerization of 1Z sensitized by DAF-Pyro was performed in nc/scCO2 at pressures
ranging from 7.8 to 14 MPa under normal and g conditions toafford 1E in ee which was highly pressure-dependent (Fig. 3).
Thus, the product’s ee rapidly increased with increasingpressure up to 11 MPa and then leveled off in both cases.
However, the pressure-dependence profile was not identical in
the two cases and appreciably higher ee values were obtained
under g particularly in the near critical region (9-10 MPa),
demonstrating that the stereochemical outcomes can be manipulated by performing chiral photoreactions in nc/scCO2 underg. Mechanistic details will be discussed in the presentation.

References

2. Results and Discussion
First, we developed a transparent cylindrical pressure vessel
made of sapphire tube (1 mL net volume), which was designed

1) Y. Inoue, E. Matsushima, T. Wada: J. Am. Chem. Soc., 120, (1998)
10687.
2) R. Saito, M. Kaneda, T. Wada, A. Katoh, Y. Inoue: Chem. Lett.,(2002) 860.

− J 26 −21A06

リング状液膜内マランゴニ対流現象に及ぼすメニスカス形状の影響に関する数値解析
山本卓也，○高木洋平，伴貴彦，岡野泰則（大阪大学），水口尚（琉球大学）

Numerical Simulation of the Effect of the Meniscus Shape on Marangoni Convection
in a Ring-Shaped Liquid Film
Takuya YAMAMOTO, Youhei TAKAGI, Takahiko BAN, Yasunori OKANO (Osaka Univ.),
Hisashi MINAKUCHI (Univ. of the Ryukyu)

1. Introduction

3. Results and Discussions

Thermocapillary and Marangoni flows are driven by
surface tension gradients along free surfaces and the flows
become remarkable under micro-gravity fields.
Onboard ISS, D. Pettit conducted an experiment in a thinwater film sustained in a circular stainless wire ring1).
When a section of the ring was heated, a thermocapillary
flow developed in the liquid film towards the heated region.
This was contrary to what predicted theoretically.
To shed light on the mechanism determining thedirection of the thermocapillary flow in a thin circular film,
we conducted a three-dimensional numerical simulation. In
the simulation, we focused on the effects of meniscus shape
and wire curvature.

In the case of Fig. 1 (a), the flow pattern was roll flownear heated wire. Symmetric vortex pair emerged near wire.

2. Numerical analysis
The governing equations of liquid phase are themomentum, continuity, and energy balance equations.
Along the free surface, thermocapillary force is in effectand the velocity gradient in the normal direction to the freesurface is proportional to temperature gradient. The freesurface is assumed to be adiabatic. On the wire wall, noslip condition was imposed, and temperature boundary
condition is analytically approximated by one-dimensional
unsteady heat conduction. The detail of the other numerical
procedures is found in T. Yamamoto et al.2).
Three computational domains are prepared to investigate
the effects of meniscus and wire curvature. Fig. 1 shows
the schematics of computational domains. The film
diameter is 10 mm; that is small compared with the spaceexperiment because of save of numerical cost.
(a)StainlessLiquid film
wire

(b)

z

1, both flows were observed.

In the case of Fig. 1 (c), the flow toward heat source wasdeveloped. Fig. 2 shows the experimental and numericalresults of particle tracers when numerical condition of film
diameter corresponds to the experiment. These numericalresults show a good agreement with the experimental result.
When the flow pattern corresponded to space experiment,
symmetric vortex pair developed near heated wire, and thevortex was stretched in circumferential direction. The flow
depended on temperature gradient along the free surfaces.
A steep temperature gradient in radial direction caused theoccurrence of symmetric vortex pair. Then, the vortex pair
was stretched by circumferential temperature gradient.
ⅰⅱ

Fig.2 Snapshots of particle tracers for numerical (left) andexperimental (right) results: (ⅰ) initial, and (ⅱ) after
heating.

Thermocapillary flow in a thin film was numericallyinvestigated. The meniscus shape and wire curvaturechanged the flow direction, and the flow pattern depended
on the temperature gradient along the free surfaces.


wm

(c)

developed. When hm/wm ≈4. Conclusion

hm

5 mm

In the case of Fig. 1 (b), meniscus shape changed flow
pattern. For hm/wm >> 1, the flow toward heat source
developed. For hm/wm << 1, the flow toward center of frame

References

y
x

1)
2)

Fig. 1 Schematic diagram of film shape: (a) flat, (b)meniscus, and (c) wire curvature.

− J 27 −D. Pettit: Saturday Morning Science Videos (2003).
T. Yamamoto, Y. Takagi, T. Ban, Y. Okano, H. Minakuchi,
and S. Dost; Proc. 23th Int. Symp. Transport Phenomena,2012.

21A07微小重力環境において液柱形状がマランゴニ対流のモード構造に与える影響○矢野大志，西野耕一（横浜国立大学），河村洋（諏訪東京理科大学），上野一郎（東京理科大学），
松本聡，大西充（宇宙航空研究開発機構）

Effect of Liquid Bridge Shape on the Mode Structure of Marangoni Convection under
Microgravity
Taishi YANO, Koichi NISHINO (Yokohama National Univ.), Hiroshi KAWAMURA (Tokyo Univ. of Science,Suwa), Ichiro UENO (Tokyo Univ. of Science), Satoshi MATSUMOTO, Mitsuru OHNISHI (JAXA)

1. Introduction
A number of microgravity (g) experiments on the Marangoni
convection have been conducted so far. Marangoni convectionis the flow that driven by the surface tension gradient along aliquid-gas interface and this flow becomes important and

VR=0.50

dominant under the g environment because of the absence ofFig. 1density driven flows. A series of MEIS (Marangoni Experimentin Space) have been started as the first science experiment on
the “Kibo” in 2008 1). The aim of MEIS is to understand theinstability mechanisms of Marangoni convection and several
parameters are considered. In this study, effects of the liquid
bridge shape on the mode structure and instability of Marangoni
convection are discussed.

Mac [-][×104]
4.0

Ma c 

VR=0.81

VR=1.08

Shape of liquid bridge for different VR

1g Experiment
Nishino(1998):
AR=0.50, 5cSt
AR=0.50, 10cSt

 T TC H
 

g Experiment
AR=0.35, 20cSt
AR=0.50, 20cSt
AR=1.00, 20cSt

3.0
2.0
1.0

2. Experiment
In the present experiment, Marangoni convection takes place
inside the liquid bridge that is suspended between coaxial
heated and cooled disks. A wide range of aspect ratio, AR(=H/D), can be realized by traversing the cooled disk in axial
direction, where H and D are the length of the liquid bridge andthe diameter of the disk, respectively. The overview of the liquid
bridge is viewed with a colored CCD camera, and the liquid
bridge shape is controlled by adjusting the fluid volume by thebellows placed behind the cooled disk. Volume ratio, VR(=V/V0), is used to collect the effect of liquid bridge shape,where V and V0 are the volume of liquid bridge itself and that of2

the gap between disks (V0=D H/4), respectively. It is known
that the liquid bridge shape is uniquely determined by AR, VR
and Bond number, Bo 2).

3. Results and Discussion
In the present experiment, three different ARs (i.e. 0.35, 0.5,1.0) are chosen to study the effect of liquid bridge shape. Figure
1 shows the liquid bridge shapes corresponding to VR=0.50,
0.81 and 1.08 for AR=0.5. The liquid bridge shape changes fromconcave to convex with increasing VR. The measured critical
Marangoni number, Mac, is plotted as a function of VR in Fig. 2.
Also included in Fig. 2 are the literature data 3) that is obtainedin terrestrial (1g) experiments. It is widely known that VR

0
0.4

0.5

0.6

0.7

0.8 0.9
VR [-]

1.0

Fig. 2Plot of Mac as a function of VR

1.1strongly affects the Marangoni instability. As shown in Fig. 2,
Mac changes with changing the VR. In the case for AR=0.5, theresults from g experiment show local peak at VR=0.55, while
such a local peak exist at VR=0.85 in the 1g experiment.
Moreover, observed mode structures of Marangoni convection
are also different between the g and 1g experiment. Under gcondition, azimuthal mode number, m, equal to 1 around
VR=0.50~1.08. While under 1g condition, m equal to 1 around
VR=0.90~1.10, but it changes at local peak and m equal to 2 isobserved around VR=0.60~0.87. This different should be causedby the effect of buoyancy.

References
1)

H. Kawamura, K. Nishino, S. Matsumoto and I. Ueno: J. Heat
Transfer, 134 (2012) 031005-1.

2)

L. A. Slobozhanin and J. M. Perales: Phys. Fluid A, 5 (1993)
1305.

3)

K. Nishino, T. Kitagawa and S. Yoda: Marangoni Convection
Modeling Res., (1999) 37.

− J 28 −21A08

可視化法を用いた微小重力中の超流動ヘリウムと常流動ヘリウムのプール沸騰熱伝達の研究○高田岡村卓（筑波大学），木村誠宏（高エネルギー加速器研究機構），間宮崇弘（高エネルギー加速器研究機構），野澤正和（秋田高専），村上幹人（産総研），
正秀（筑波大学）

Study of Pool Boiling Heat Transfer in Superfluid Helium and Normal Liquid Helium under
Microgravity by using Visualization Method
Suguru TAKADA (Univ.of Tsukuba), Nobuhiro KIMURA (KEK), Mikito MAMIYA (AIST), Takahiro
OKAMURA (KEK), Masakazu NOZAWA(Akita National Tech.), Masahide MURAKAMI (Univ. of Tsukuba)

1. Introduction
Superfluid helium (He II) is used as a coolant for astronomy
satellite such as X-ray telescope1). Thus the investigation of
He II heat transfer has been required. It is well known that thecritical heat flux of He II is strongly dependent on small
subcooling due to hydrodynamic pressure head. Under genvironment, the subcooling of He II would be absolutely zeroso that the present experiment would be very important.
Therefore the present experiment was carried out by using
drop-tower in order to understand He II film boiling under
microgravity condition. Small cryostat equipped with optical
windows and visualization system was embedded in the capsuleof the drop tower at Hokkaido center of AIST. And in the caseof normal liquid helium (He I), the film boiling experiment wasalso carried out for comparison.

2. Experimental Apparatus and Drop Tower in
Hokkaido Center, AIST

as shown in Fig.1. The time duration of microgravity
environment below 1 mili-g is about 1.3 sec.

3. Visualization Results
In He II film boiling, the very thin vapor film was formed andvapor bubble was never departed on 1G. The thickness ofvapor film is about 0.2 mm. On the other hand, vapor film wasgetting much larger more than 20 mm under g condition asshown in Fig. 2 (a) and (b). The nucleate boiling state was neverobserved under g as same as on 1G.

The typical visualization results of He I boiling were shownin Fig. 3(a) and (b). It is found that nucleate boiling and film
boiling can be recognized clearly. In nucleate boiling state,small vapor bubbles departs from thin heater wire. On theother hand, in film boiling state, vapor bubbles formed large
bubbles of about 6 mm diameter and small oscillating bubble of
1mm diameter periodically. And the vapor bubbles neverdepart from wire heater.

We designed the small cryostat equipped with optical
windows for the experiment using by the drop tower2). The
test vessel is about 5 litters. A thin manganin wire heater of
φ50 m was set horizontally.

Electric resistance of manganin

has positive relation with temperature at low temperature.
Thus a thin wire heater was also used as a thermometer. The
heat current has applied with the constant power supply that hasa feed-back control was used for fixed heat flux condition.
The high speed camera was used in this present study. The
frame rate had been 231 frames/sec. The flat LED lightilluminates from the side of a window glass and the high speed
camera with telecentric lens was set opposite side.

a)

b)
Fig2

visualization results of He II film boiling at 1.9 K,

q = 22.3 kW/m2 (a) 1G (Zoom up x4) (b) under g.

b)

a)
Fig.3

typical visualization results of He I at 4.2 K under g(a) nucleate boiling q=9.70 kW/m2 (b) film boiling q=22.3
kW/m2.

References

Fig.1

1)

Fujimoto R., Mitsuda K., et. al., Cryogenics 50 (2010) 488.

2)

N. Kimura, S. Takada, S. Gotoh, H. Kawamata, M. Iida, M.
Murakami, H. Nagai and M. Mamiya, Cryogenics51 (2011)74.

Rough sketch of optical setup.

− J 29 −21A09温度差マランゴニ効果による懸垂液滴内粒子挙動と Hydrothermal wave 不安定性
○渡邉拓実，上野一郎 (東京理科大学)

Particle behavior and hydrothermal wave instability
in hanging droplet due to thermocapillary effect
Takumi WATANABE, Ichiro UENO (Tokyo Univ. of Science)

1. Introduction

Acknowledge

We has been focusing on thermocapillary-driven convection
in a hanging droplet with experimental approaches1. We realizea transition of the flow field from a two-dimensional steady flow
to three-dimensional time-dependent ‘oscillatory’ ones. The
oscillatory flow is accompanied with a thermal wave travelingover the free surface at a constant frequency. Such a thermal
wave induced by the thermocapillary effect is known as thehydrothermal wave instability2 (HW, hereafter). In the present
research, we evaluate the transition point of the flow inside thedroplet, and the fundamental frequency of the oscillatory flow
after the transition. We make a comparison of the present datawith the ones by on-orbit experiments in the JapaneseExperimental Module ‘Kibo’ aboard the International Space
Station3.
Cooled rod

The authors acknowledge Prof. Koichi Nishino (Yokohama
National University), Prof. Hiroshi Kawamura (Tokyo
University of Science, Suwa), Mr. Mitsuru Ohnishi, Dr. Masato
Sakurai and Dr. Satoshi Matsumoto (Japan Aerospace
Exploration Agency (JAXA)) for fruitful discussion. This
research was conducted as an activity of the International
Research Division on Interfacial Thermo-Fluid Dynamics(I2Plus) in Research Institute for Science & Technology atTokyo Univ. of Science. This work was supported by Research
Fund of Tokyo University of Science in JFY2011.

References
1)

T. Takakusagi, I. Ueno, and C. Hong, Bulletin European Low
Gravity Research Association 27 (2010) 32.
M. K. Smith and S. H. Davis, J. Fluid Mech. 132 (1983) 11.
H. Kawamura, K. Nishino, S. Matsumoto, and I. Ueno, J. Heat
Transfer 134 (2012), 295.

2)
3)Particles
Particles

Heated rod
periphery

3 [mm]

Particle

Heated rod(a) periphery

(b)

(a)
DropletDropletHeated rod

Heated rod

Fig. 1 Example of view obtained by one of the top view cameras (a) and side view
camera (b) in on-orbit experiments (MEIS-3)(b)

2. Experimental condition
The droplet is formed on the top rod facing downward, andthe bottom rod is placed beneath the droplet. We use two kindsof top rods, whose radius is of 1.0 and 1.5 mm. The test fluids
are 2 and 5-cSt silicone oil with Prandtl number Pr of 28.1 and68.4 at 25 °C, respectively. The physical properties of the fluid
are listed in Table 1. We observe the flow fields with two highspeed CMOS cameras, and simultaneously measure the surface
temperature with an infrared camera (IR camera) whose frame
rates are 60 fps.

(1) (c)Direction of HW

(a)

(b)

(2) (c)

3. Results and Discussion
The intensity of the flow induced by the thermocapillaryeffect is described by using a non-dimensional Marangoni
number Ma ( =(TT(V/R2))/ ), where T is temperature
coefficient of surface tension, T is temperature difference ofboth rods, V is volume, R is radius of the top rod,  is density,is kinematic viscosity,  is thermal diffusivity. We detect themin variations of the R of the rods and of the Prandtl number Prof the test fluid. The critical marangoni number Mac increases
monotonically when the aspect ratio  (=H/R) decreases at eachexperimental condition; it is found that the Mac is welldescribed with Results of MEIS-3 are in good agreementwith terrestrial experiments. The non-dimensional frequency F( =(H2/)*f ) is plotted against Ma. It is clearly seen that the F
exhibits a condensed manner against the Ma almost
independently of R and Pr. The results obtained in MEIS-2 andMEIS-3 are in good agreement with the terrestrial experimentsin spite of rather large differences of R and Pr.

(a)

(b)

(3) (c)(i) t = t0(ii) t = t t(iii) t = t 2t (iv) t = t 3t (v) t = t 4t-0.3(vi) t = t  5t
0

0.3

Fig. 2 Time series of snapshots of each flow regimes; (1) Steady flow, (2) Traveling
flow, and (3) Dynamic PAS flow at time interval t [s] of (1) 0.372, (2) 0.178 and(3) 0.117, respectively. Spatio-temporal correlation between particle line observed(a) from above, (b) from side, and (c) the surface temperature deviation observed
from another side, respectively. The temperature difference in snapshots oftemperature deviation is.3 [K]. The HWs of (2) the Traveling wave and (3) the
Dynamic PAS flow propagate from the left to the right in the frame (i.e.,counterclockwise) in these cases. Schematic views are drawn aside the last image ofparticle lines. Outer circle in the top view corresponds to the periphery of the top
rod whose radius is 1.5 mm.

− J 30 −21A10

強い重力場を用いた反ポーリング則構造を持つ TiO2 の合成○ 真下茂、Rabaya BAGUM、緒方雄大（熊大）、奥部真樹（東工大）、杉山和正（東北大）、
磯部 博志（熊大）、吉朝 朗（熊大）Synthesis of Anti-Pauling Structure Rutile (TiO2) Produced under Strong Gravitational Field
Tsutomu MASHIMO, Rabaya BAGUM, Yudwai OGATA(Kumamoto University), Maki OKUBE(Tokyo Instt. Tech.),K. SUGIYAMA(Tohoku University), Hiroshi ISOBE, Akira YOSHIASA(Kumamoto University)
1. Introduction
Rutile type TiO2(D4h14) essentially consists of edgesharing distorted TiO6 octahedral groups (Ti-Oa -1.947 Å,and Ti-Ob:1.9808 Å) and Ti ions form a tetragonal latticewhich is compressed along with c-axis. We haveinvestigated the effect of application of a strong
gravitational field during heat treatment on the crystal
structure and properties of single-crystal rutile (TiO2)
using the high-temperature ultracentrifuge1). Under astrong gravitational field (~106 G level), heavy atoms are
displaced in the gravitational direction, and light atoms in
the opposite direction by the different body forces relative
to respective atomic weight in compound crystal. Under
such conditions, a unique atomic strain further thenonequilibrium crystalline state would appear, and ametastable form might be quenched to ambient condition.
2. Experimental procedure
Single crystal plate specimens, 5 mm diameter and
1 mm thick were set on a sapphire plate in a stainless steel
SUS304 capsule. The gravitational field was appliedalong the c-axis of the crystal with the maximum distancefrom the rotor axis being about 35.5 mm. The gravity at
the sample for a rotation velocity of 100,000 rpm was(0.39-0.40) × 106 G. The rotor was radiatively-heated to
400°C by a hot carbon, hollow cylinder which in turn washeated by a high frequency heating system. The duration
was 24 hours. Single-crystal X-ray diffraction
measurements for crystals were carried out with a fourcircle diffractometer at the BL-10A beam line of the
Photon Factory. Structure refinements were performed byminimizing the function w (Fo–Fc) 2 using a fullmatrix least-squares program, RADY (23).
3. Results and discussion
Figure 1-a shows comparisons of the c/a ratios
obtained by gravity with those from pressure 2) andtemperature 3) variations. The axial ratio c/a increases withincreasing pressure i.e., the a-axis is more compressible
than the c-axis. For the centrifuged sample, the lattice
constant c decreased (0.3%) and a increased (0.05%); thus
the c/a ratio decreased, and the structure became moreanisotropic. The changes in lattice constant may also be
related to the fact that gravity is body force and wasapplied along the c axis.
Figure 1-b shows the ratio of the distances Ti–Oa
and Ti–Ob of the rutile phase, and compares the effect ofgravity treatment with those of pressure 4) and temperature 3).
The Ti–Oa and Ti–Ob distances in the present sample
increased by 0.7 % and decreased by 0.9 %, respectively.
The ratio of these two interatomic distances increased,
and approached 1 (0.997). To obtain the same state usingpressure, we would need to apply over 140 GPa. In thepresent sample, Os and Ou are 2.613Å (3.2% enlarge thanfor standard rutile) and 2.7728Å (0.16% less thanstandard rutile), respectively. As a result, Os/Oa
approached 1 (0.9224), implying a more isotropic state. It
is notable that the Ti-O6 octahedral structure approaches
the isotropic state, which is against Pauling’s rules.

Fig. 1 The c/a (a) and Ti–Oa / Ti–Ob (b) ratios for rutile of thegravity sample as compared with pressure 3) and temperaturedependences 4).

We could stress a bit more that this method is
general and could be applied to many common materials;
it produces very different results than static high pressure
and at least based on this work it overcomes many of the
difficulties associated with producing new materials.
References
1)
2)
3)
4)

− J 31 −T. Mashimo et al., Rev. Sci. Instr. 74, 160 (2003).
L. Gerward, J. Staunolsen, J. Appl. Cryst., 30, 259 (1997).
K. Sugiyama, Y. Takeuchi, Zeitchrift Fur Kristallographie,
194, 305, (1991).
Y. Kudoh, H. Takeda, Physica B. 139-140, 333, (1986).

21A11

強い重力場下における拡散対の界面拡散○ 緒方裕大、近藤慶祐、坂田祐樹、井口裕介、真下茂（熊本大学

真下研究室）

Diffusion Phenomenon at Interface of Metal Couples under a Strong Gravitational Field
Yudai OGATA, Keisuke KONDO , Yuki SAKATA, Yusuke IGUCHI, Tsutomu MASHIMO (Kumamoto Univ.)

1. Introduction

3. Results

To know advantage of microgravity, we should know about
the gravity effect. Strong gravity is suitable for the study of thegravity effect and would reveal the gravity effect in more visible
form.
Electronic device such as semiconductor or metal or etc. is
indispensable for life and development of human civilization.
The interface is important for functionality of the electronic
device. So, we need control interface at atomic-scale fordevelopment of new electronic device.
The experiment of diffusion using the Copper-Brass diffusion
couple was performed by Dr. Kirkendall in 19471). He found thevacancy mechanism; it is not only substitution and interstitial
ones and it is called Kirkendall effect. So, this Copper-Brass
diffusion couple is very famous example.
In this study, we performed the strong-Gravity experiment on
Cu-Brass couple to study the interface diffusion phenomena.

Figure 1 shows EPMA color mapping of Copper-Brass after
ultracentrifugal experiment. The black area in figure indicatesnothing Zinc, and containing many Zinc when color movetoward warm color. Experimental gravity direction was upside:
Copper and downside: Brass. We confirmed that interface
between Zinc contained in Brass and Copper blurred the same
phenomenon as annealing experimental result. We compared
ultracentrifuged Cu-Brass chart with annealed one chart, then,we found that the composition gradient at the interface ofultracentrifuged Cu-Brass was gentler than the annealed one. On
the other hand, when gravity direction was upside: Copper anddownside: Brass. We observed that the composition gradient at
the interface of ultracentrifuged Cu-Brass steeper than theannealed one. So, we considered thermal diffusion andsedimentation under strong gravitational field. In case of upside:
Copper gravity direction, first, Copper and Zinc move toanother metal due to the thermal diffusion. Then, because of agravitational field, Copper atoms move to the gravity direction.
Zinc atoms move to the opposite direction. So, the movement of
Copper under the gravitational field enhanced the thermal
diffusion. Just the same, in upside: Brass case, the movement ofthese atoms under the gravitational field blocked the thermal
diffusion. As a result, in a strong gravity field, gravity effect cancontrol the thermal diffusion.

2. Experimental procedure
We prepared We prepared metal couples of Cu/Brass(Cu:Zn=70:30 at. %) using the electroplating method. Then we
have gotten copper-plated Brass at the cathode about 2mm inthickness. Copper-plated Brass was cut into specimens ofapproximately 5 mm in diameter and appearing interface clearly.
We prepared two type samples, one is that Copper was upsideand Brass was downside, and another is that Brass was upsideand Copper was downside. In this study, we used plate typecapsule. As a result, interface of specimens were applied thecentrifugal force vertically. The rotor can be heated by a hot
carbon, hollow cylinder which in turn is heated by a highfrequency heating system. Experimental conditions are
summarized in Table 1. We performed also the annealing
experiment at 1G, the same temperature, and for the same time
duration to compare with usual thermal diffusion. The
composition analysis was performed using electron probe micro
analysis with a JXA-800R (Japan Electron Optics Laboratories
Co., Ltd).
Table 1 Experimental condition
Rotation
Maximum
Temperature
(℃)
speed
acceleration(rev×min-1)(×106G)Time(h)

100 000

60

0.4

400

Cu

Gravity
direction

Cu

Ultracentrifuged

Ultracentrifuged

Zn

Zn

Gravity
direction

Fig.1 The concentration distribution of the ultracentrifuged
Cu-Brass Left(Upside: Cu and Downside: Brass)
Right(Upside: Brass and Downside: Cu)

References1)− J 32 −A. D. Smigelskas and E. O. Kirkendall: Zinc Diffusion in Alpha
Brass. Trans. AIME, 171 (1947), 130-142.

21A12

強い重力場を使った機能熱電傾斜材料の作製○Januszko KAMILA (AGH University, 熊本大学), Wojciechowski KRZYSZTOF,
Zybala RAFAL (AGH University, Poland), 緒方裕大, 真下茂 (熊本大学)

Preparation of Functionally Graded Thermoelectric Materials under Strong Gravitational Field
Kamila JANUSZKO (AGH University, Poland; Kumamoto University, Japan), Krzysztof WOJCIECHOWSKI,
Rafal ZYBALA (AGH University, Poland), Yudai OGATA, Tsutomu MASHIMO (Kumamoto University, Japan)

1. Introduction
Thermoelectric materials can be used for the conversion ofheat energy into electricity. They found application e.g. inindependent power supplies, so called thermoelectric generators
TEG, that do not need maintenance for many years (e.g. inspace probes Voyager 1, 2). However, the efficiency of thecommercially available materials is that of only around 5%,
what limits their common applications in daily use.
Thermoelectric materials efficiency and their properties
depend on carriers’ concentration and temperature, however
increasing temperature gradient is limited by physical propertiesof the material. Therefore gradation of the carriers’
concentration inside the material seems to be the best solution.
As a result of gradation, efficiency of the material should
increase significantly comparing to uniform material.
A strong gravitational field realized the sedimentation of
atoms in solid, i.e. an atomic-scale graded structure1), 2).
Kumamoto University ultracentrifuge apparatus can generate an
acceleration over one million G (1G=9.8m/s2) at hightemperatures. Previous research of grading different materials
using these apparatus gives high expectations of applying thismethod for the research.
This research concentrates on preparation of functionally
graded thermoelectric materials to enhance their properties andefficiency, using gravitational field as a grading factor.
To perform effective gradation the material with heavy andlight atoms is required. Then, according to gravity force
movement of light atoms in the direction of gravity force andheavy atoms against this direction can be observed. For thisreason the thermoelectric materials of AgSbSe2 and BiSbTe3
were used. Both of these are very good thermoelectric materials.
Especially AgSbSe2 was interesting for this research, according
to its unusual properties3), 4).

where α-Seebeck coefficient, σ-electric conductivity, λ-thermal
conductivity, T-temperature.
Optimization of given thermoelectric properties allows to gethighest possible ZT for the material. For this study
thermoelectric properties analysis Seebeck coefficient as
a representative thermoelectric property was measured using
STM (Scanning Thermoelectric Microprobe) (AGH University,
Poland).
Experimental results show small gradation in chemical
structure for both materials that were previously uniform. As
Seebeck coefficient differences can be seen even due to smallchange in carriers’ concentration, more significant effect isvisible. Gradation effect on the samples can be observed on thefollowing figure (Fig.1.)b)a)Fig.1. AgSbSe2 sample after the high gravity experimentat 120 000 r/min, 400°C: a) EPMA analysis, b) colour mapof Seebeck coefficient distribution

4. Conclusions
The change in chemical structure and thermoelectric
properties were observed. Other thermoelectric materials should
also be investigated. Longer time of performing the experimentcan be considered for more significant effect.

References
2. Experimental and results
Experiment was performed using ultracentrifuge apparatus
with conditions of 120 000 rot/min in 400°C for both samples.
Change in chemical structure in materials was confirmed
using EPMA analysis.
For estimating thermoelectric material efficiency, usually ZT
value (figure of merit) should be calculated:
ZT  2 
 Taver− J 33 −1)

T. Mashimo, Phys. Rev. A 38, 8, (1988) 4149

2)

T. Mashimo, Acta Astronaut. 48, (2001). 145

3)

K.T. Wojciechowski and M. Schmidt, Phys. Rev. B 79,(2009) 184202

4)K. Wojciechowski, M. Schmidt, J. Toboła, M. Koza,
A. Olech, R. Zybala, J. of Electr. Mat., Vol. 39, No. 9, 2010,2053-2058

21A13

過冷却融液からの Cr-Si 系熱電材料の合成○永井秀明（産総研）、濱田剛、奥谷猛（横国大大学院）

Synthesis of Cr-Si Thermoelectric Material by using Undercooled Melt
○Hideaki NAGAI (AIST), Tsuyoshi HAMADA, Takeshi OKUTANI (Yokohama Nat. Univ.)

1. Introduction
CrSi2 is known as a candidate for thermoelectric applications,and has been reported to have large anisotropy of thermoelectric
properties against c-axis1). To synthesize thermoelectric Cr-Si
alloy with higher performance, it is important to control both
crystalline alignment and metallurgical structure. Our previous
works has revealed that the structure control of Si-Ge alloy and
ZrNiSn alloy solidified in microgravity are useful to improvetheir thermoelectric performance2,3).
Recently, we havesynthesized Si-Ge alloy with metallurgical structure andcrystalline alignment solidified from undercooled melt using
electromagnetic levitation (EML) method. In this study, weinvestigated the synthesis of Cr-Si alloys by using EML method.

sample. From the XRD pattern, the arc-melted sample wasconsidered to be a mixture of large grains with crystallinealignment. The samples with different Cr/Si ratio solidified
from undercooled melt also had fine metallurgical structure
without crystalline alignment.
(a) Arc-melted CrSi2(b) Solidified CrSi2 fromthe melt of 1680K

1mm
Cold copper plate side
Cooling chill contact

Fig.1 Cross section of CrSi2 sample solidified from the melt.

2. Experimental
Cr-Si alloys with different Cr/Si ratio were prepared by arcmelting from the constitute elements. 5 at% of Cr component
was substituted by V as a dopant.
Our EML equipment has He gas cooling system, and the melt
sample can be cooled during levitation. The sample waslevitated in Ar gas flow at first, and kept above melting point(m.p.) for 2 min. The sample was cooled down by introducing
He gas. When the melt temperature was reached around 1680
K, lower than m.p. of CrSi2 (1763 K), the sample was solidified
by contact of Si chill block. The structure of the solidified
sample was analyzed by XRD, OM and SEM.
The
thermoelectric properties was evaluated by electricalconductivity, Seebeck coefficient and thermal conductivity.

Table 1 shows the thermoelectric properties of the sample
with different Cr/Si ratio at 900 K. All arc-melted samples had
lower electrical conductivities because of cracks in the sample.
Cr-rich sample had higher electrical conductivity because thissample was a mixture of CrSi2 and CrSi phase and CrSi phase isa metallic phase. On the other hands, Cr-poor sample had
lower electrical conductivity because this sample was a mixtureof CrSi2 and Si phase and this Si phase was a semiconductor
phase without doping. The Seebeck coefficients of the CrSi2
samples were similar to those of Cr-poor sample because of thesame V-doping concentration in CrSi2 phase. The lower
Seebeck coefficient of Cr-rich sample was caused by increasing
V-doping concentration in CrSi2 phase, because V was rarely
dissolved in CrSi phase.
Table 1 Thermoelectrical properties of Cr-Si alloys at 900 K

3. Result and discussion
All samples with different Cr/Si ratio could be levitated by
EML method. Several samples could be cooled down around
1680 K without solidification by introducing He gas, but the
sample with 44at% Cr component could not be cooled down
below m.p, even though introducing He gas of more than 200
ml/min.
Figure 1 shows the cross sections of CrSi2 solidified from themelt by different solidification method. The sample solidified
from undercooled melt had fine metallurgical structure without
crystalline alignment. This result revealed that solidification
rate from the melt with undercooled degree of 70 K was so fastthat the sample was randomly solidified. On the other hands,
the arc-melted sample had large grains and many cracks in the

Solidified
sample fromundercooled
melt

Arc-melted
sampleCr compoment(included V)
36
Electricalconductivity (S/m)
2.44E+05
Seebeck coefficient(mV/K)
62.5
Thermal conductivity non(W/mK)
measurement
ZT
Electricalconductivity (S/m)
2.72E+04
Seebeck coefficient(mV/K)
56.8

33.3

29

4.45E+04

2.47E+04

109

102
non2.41 measurement
0.20
2.04E+04

1.60E+04

1.11E+02

100

References
1)
2)

I. Nishida: J. Mater. Sci., 7 (1972) 1119.
T. Okutani, Y. Kabeya, H. Nagai: Proc. 7th Interdisciplinary
Transport Phenomena Conference, Dresden/Germany, Sep. 2011,
13-3.

3)

H. Nagai, R. Muroi, T. Okutani: J. Phys, 327 (2011) 012008-1.

− J 34 −21A14

チタニアナノスケルトンの微小重力下における調製とその物性○遠藤健司、酒井秀樹、阿部正彦、（東京理科大学）畠山望、宮本明、（東北大学）
酒井俊郎、（信州大学）羽生直人、（資生堂リサーチセンター）坂本一民、（千葉科学大学）福井寛、（福井技術士事務所）勝田真登、越川尚清（宇宙航空研究開発機構）

Preparation of Titania Nanoskeleton in Microgravity and Its Properties.
○Takeshi ENDO, Hideki SAKAI, Masahiko ABE, Nozomu HATAKEYAMA, Akira MIYAMOTO, Toshio
SAKAI, Naoto HANYU, Kazutami SAKAMOTO, Hiroshi FUKUI, Masato KATSUTA, Naokiyo KOSHIKAWA

1.Introduction

3. Results and discussion

Synthetic inorganic mesoporous materials like MCMs havevarious potential applications due to their regularly arranged
mesopores. Among such mesoporous materials mesoprous
titania is expected as a candidate for novel photocatalyst,
chemically stable molecular sieve and so on. Althoughgenerally crystalline titania is obtained through heating ofamorphous particles, we succeeded in synthesis of crystalline
mesoporous titania near room temperature by using aquarternary ammonium type cationic surfactant as a structure
directing agent and named the obtained material as titania
nanoskeleton. We attempted synthesis of titania nanoskeleton in
microgravimetric environment.

All samples were successfully retrieved. The appearance ofthe samples was almost the same with that of terrestrial controls.
SAXS patterns show that nanoskeletons prepared in ISS also
shows hexagonal mesoporous structure.
The interpore
distance increased as compared with terrestrial controls asshown in Fig. 2. In the cases of the samples prepared without
TMB, regularity of the porous structure improved significantly.
Anatase crystalline sizes of the framework were almost same forboth cases. Diameter of the aggregates reduced in 2-30 % by
SEM observation. These results show that microgravity
environment has significant effect on interpore distance of thenanosleletons prepared with oil phase (TMB), while uniformityof the pore is improved for the samples prepared. And
photocatalytic activity improved for the samples that has moreordered structure.

2. Experimental
Titanium oxysulfate and trimethyl benzene (TMB) aqueous
suspension / cetyltrimethylannonium bromide (CTAB) aqueous
solutions are packed separately in three fold polyethylene bag
before launch. (Fig. 1)
Sample bags were stowed inrefrigerator before experiment in ISS. Sawed precursors weremixed together and followed by 3 days reaction at 40 ℃ .
Obtained particles are analyzed after filtration and drying on
ground. Mesoporous structure was investigated by transmission
electron microscopy and small angle X-ray scattering. Pore
diameter was investigated by nitrogen gas adsorption desorption
measurement at 77 K. Photo catalytic activity was examined for
isopropanol gas decomposition.

Fig. 2 Pore to pore distance (d100) of the obtained
nanoskeletons with various TMB/CTAB ratio. ○represents the d100 values of terrestrial control
samples and × represents those of the samples
obtained in microgravity.

References(1) H. Shibata et al, J.Am.Chem.Soc.127, 16396 (2005)

Fig. 1 Appearance of sample mixing bag. Clip separates the
precursor solutions until the experiment starts.

− J 35 −