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Ir
Sn
(
: La and Ce) investigated using neutron and X-ray diffractionNakazato, Seiya*; Iwasa, Kazuaki*; Hashimoto, Daisuke*; Shiozawa, Mami*; Kuwahara, Keitaro*; Nakao, Hironori*; Sagayama, Hajime*; Ishikado, Motoyuki*; Ohara, Takashi; Nakao, Akiko*; et al.
JPS Conference Proceedings (Internet), 30, p.011128_1 - 011128_6, 2020/03
-butadiene) rubbersYamaguchi, Daisuke; Yuasa, Takeshi*; Sone, Takuo*; Tominaga, Tetsuo*; Noda, Yohei*; Koizumi, Satoshi*; Hashimoto, Takeji*
Macromolecules, 50(19), p.7739 - 7759, 2017/10
Times Cited Count：18 Percentile：52.64(Polymer Science)We elucidated the spatial distribution of filler particles in cross-linked poly(styrene--butadiene) rubbers (SBR) developed under a typical fillers/rubbers compounding process as one of dissipative structures formed under a stress field imposed on the given system. The dispersion state of the fillers in SBR was clarified on the basis of hierarchical structures consisting of five structure levels. More specifically, it has the following characteristics depending on the specific interactions: Small, compact clusters build up compact mass-fractal structures, while large, loose clusters build up open mass-fractal structures.
Yokota, Sho*; Chugo, Daisuke*; Hashimoto, Hiroshi*; Kawabata, Kuniaki
Proceedings of 25th IEEE International Symposium on Robot and Human Interactive Communication, p.910 - 911, 2016/08
The purpose of this paper is to experimentally investigate specific ranges of play (software backlash, deadzone) on the saddle type interface for the personal mobility (PM), and to implement them into the control scheme.
Yamaguchi, Daisuke; Miyamoto, Nobuyoshi*; Fujita, Takako*; Nakato, Teruyuki*; Koizumi, Satoshi; Ota, Noboru*; Yagi, Naoto*; Hashimoto, Takeji
Physical Review E, 85(1), p.011403_1 - 011403_15, 2012/01
Times Cited Count：23 Percentile：75.20(Physics, Fluids & Plasmas)Phase transition of aqueous colloidal dispersions of charged plate-like particles of niobate nanosheets were investigated as a function of the aspect ratio (
) and particle volume concentration (
) by small-angle neutron scattering and small-angle X-ray scattering. The results elucidated the following three pieces of evidence: (1) the macroscopic phase separation of the dispersions into an isotropic phase and a liquid crystalline phase (LC) under the condition of (a) varying at a constant = 0.01, and of (b) varying (0.01 
0.025) at a constant = 2.5
10
. (2) the -induced phase transition of the LC phase from a nematic phase to a highly periodic layered phase upon increasing r under the condition (a). (3) the LC phase having remarkable concentration fluctuations of the particles which are totally unexpected for the conventional lyotropic molecular LC but which are anticipated to be general for the plate-like colloidal particles.
Iwase, Hiroki; Koizumi, Satoshi; Iikura, Hiroshi; Matsubayashi, Masahito; Yamaguchi, Daisuke; Maekawa, Yasunari; Hashimoto, Takeji
Nuclear Instruments and Methods in Physics Research A, 605(1-2), p.95 - 98, 2009/06
Times Cited Count：36 Percentile：89.44(Instruments & Instrumentation)We constructed an in-situ and simultaneous observation method as a result of combination between ultra-small-angle neutron scattering and neutron imaging (radiography). With this novel technique, we are able to visualize water distribution or transportation, occurring from micro to macro length scales in a polymer electrolyte fuel cell (PEFC). At a sample position of SANS-J-II at JRR-3, we installed a neutron imaging camera in order to construct an in-situ and simultaneous observation method by USANS and neutron imaging with monochromatized cold neutrons. In addition, in order to selectively observe MEA in a running PEFC by using the in-situ and simultaneous observation method, we need to replace carbon separators which cause strong small-angle scattering as a noise. To reduce this strong background, we replaced the carbon separators with the aluminium ones. As a result, the background scattering was minimized (1/10) as compared to before.
Fran
ois, C.*; Yamaguchi, Daisuke; Hashimoto, Takeji
Macromolecules, 41(13), p.4828 - 4837, 2008/07
Times Cited Count：30 Percentile：64.81(Polymer Science)Thermoreversible order-order transitions between various morphologies occurring on binary mixtures of diblock copolymers were investigated by using small-angle X-ray scattering. The complex morphological behaviors observed here can be understood on the basis of two key features of the binary blends: the co-surfactant effect and the possibility for the chemical junctions of the shorter diblock to migrate away from the interface as segregation power decreases. As a summary of this series of studies, a three-dimensional phase diagram was constructed in the parameter space of overall volume fraction of polystyrene block in the mixture, the ratio of the degree of polymerization of long asymmetric diblock chain to that of short symmetric diblock chain and temperature. Such a phase diagram illustrates that the cosurfactant effect opens perspectives in tailoring morphologies of self-assembled, nano-structured materials.
Yamaguchi, Daisuke; Mayama, Hiroyuki*; Koizumi, Satoshi; Tsujii, Kaoru*; Hashimoto, Takeji
European Physical Journal B, 63(2), p.153 - 163, 2008/05
Times Cited Count：13 Percentile：49.22(Physics, Condensed Matter)The unique structure of a set of self-assembled porous silica materials was characterized through a combined small-angle scattering (CSAS) method using small- and ultra-small angle neutron scattering as well as small-angle X-ray scattering. The porous silica specimens investigated were prepared by a sol-gel method under the presence of alkylketene dimer (AKD) template particles and through calcination, which leads to the development of porous silica having a mass-fractal structure over length scales from 10nm to 10
m. Furthermore, the specimens posses a hierarchical structure, which consist of a fractal porous structure, and also contain primary silica particles less than 10 nm in size, which form a continuous silica matrix. To characterize these complex structures, observation over a broad range of length scales is indispensable. We propose a CSAS technique that serves this purpose well.
Yamaguchi, Daisuke; Mayama, Hiroyuki*; Koizumi, Satoshi; Tsujii, Kaoru*; Hashimoto, Takeji
European Physical Journal B, 63(2), p.153 - 163, 2008/05
The fractal dimensions of specific porous silica materials were investigated by a wide-q observation using ultra-small-angle neutron scattering technique. In order to control the fractal dimension of porous silica material, flaky particles made of alkylletene dimer (AKD) were employed as moulds and silica matrix was formed by sol-gel process. After the solidification of the silica matrix, the original AKD moulds were completely burnt away at high temperature (ca. 930K) and became pores having a particular fractal dimension. The fractal dimension of the pores was changeable by the compression of the AKD mould at different ratio during the sample preparation. We found that the fractal structure obtained in this study was distinctly different from those of ordinary silica aerogels.
Koizumi, Satoshi; Zhao, Y.; Tomita, Yoko*; Kondo, Tetsuo*; Iwase, Hiroki; Yamaguchi, Daisuke; Hashimoto, Takeji
European Physical Journal E, 26(1-2), p.137 - 142, 2008/05
Times Cited Count：58 Percentile：86.12(Chemistry, Physical)no abstracts in English
Koga, Tadanori*; Hashimoto, Takeji; Takenaka, Mikihito*; Aizawa, Kazuya; Amino, Naoya*; Nakamura, Masao*; Yamaguchi, Daisuke; Koizumi, Satoshi
Macromolecules, 41(2), p.453 - 464, 2008/01
Times Cited Count：127 Percentile：95.72(Polymer Science)Using a combined ultra-small-angle and small-angle scattering method of neutrons and X-rays, we investigated hierarchical structures of carbon black (CB) highly loaded in polyisoprene (PI) and poly-(styrene-random-butadiene) copolymer (SBR) under mechanical field (defined respectively as CB/PI and CB/SBR) as well as in toluene under a sonic field (defined as CB/toluene). Comparison of the scattering profiles from CB/PI and CB/SBR with CB/toluene clarified that (1) the smallest structure elements of CB in PI and SBR were composed of the several unbreakable units bounded together by polymer chains (defined as "dispersible units") and (2) sizes and shapes of the dispersible units depended on the polymer matrix. (3) Moreover, the enlarged size of the dispersible unit in PI was found to enlarge the upper cutoff length of the mass-fractal structure in PI, while the mass-fractal dimensions themselves remained unchanged between PI and SBR.
Hashimoto, Daisuke*; Komatsu, Keiichi*; Eguchi, Kenji*; Morizono, Koji
FAPIG, (175), p.23 - 28, 2007/07
The fast breeder reactor "MONJU" (hereafter "MONJU") is equipped with the system called "MONJU Integrated Data Acquisition System (MIDAS)" to effectively acquire, accumulate and analyze relevant real-plant process data gathered from the system start-up test. At present, "MONJU" has been suspended due to a sodium leak accident that occurred in 1995. However, the main part of remodeling construction to prevent sodium leaks was completed in May, 2007 and "MONJU" is highly expected to resume its operations, stepping into the practical testing phase. In this situation, "MIDAS" has been replaced with an upgraded version before the system start-up test was resumed. This paper describes overview of the new "MIDAS" system.
Yamaguchi, Daisuke; Miyamoto, Nobuyoshi; Koizumi, Satoshi; Nakato, Teruyuki*; Hashimoto, Takeji
Journal of Applied Crystallography, 40(s1), p.s101 - s105, 2007/04
Times Cited Count：22 Percentile：85.70(Chemistry, Multidisciplinary)no abstracts in English
Yamaguchi, Daisuke; Koizumi, Satoshi; Motokawa, Ryuhei; Kumada, Takayuki; Aizawa, Kazuya; Hashimoto, Takeji
Physica B; Condensed Matter, 385-386(2), p.1190 - 1193, 2006/11
Times Cited Count：15 Percentile：54.95(Physics, Condensed Matter)A new tandem analyzing system was introduced on Bonse-Hart ultra-small angle neutron scattering (USANS) spectrometer. In the normal setup of USANS it consumes a considerable time to take a scattering profile of whole q-range (210
nm
q 710
nm, where q denotes magnitude of scattering vector) due to the step scan system, in which the scattering waves from the sample and having different q are measured step by step. To overcome this difficulty two analyzer channel-cut silicon perfect crystals were settled in tandem and each of them diffracted the scattering wave of different q. In consequence, a simultaneous detection at two different q positions was realized and the measurement time was reduced to half.
Koizumi, Satoshi; Iwase, Hiroki; Suzuki, Junichi; Oku, Takayuki; Motokawa, Ryuhei; Sasao, Hajime*; Tanaka, Hirokazu; Yamaguchi, Daisuke; Shimizu, Hirohiko; Hashimoto, Takeji
Physica B; Condensed Matter, 385-386(2), p.1000 - 1006, 2006/11
Times Cited Count：42 Percentile：81.16(Physics, Condensed Matter)no abstracts in English
Noda, Yohei; Yamaguchi, Daisuke; Hashimoto, Takeji; Shamoto, Shinichi; Koizumi, Satoshi; Yuasa, Takeshi*; Tominaga, Tetsuo*; Sone, Takuo*
no journal, ,
We have developed a proton spin contrast variation technique. It has been known that a good DNP performance is achieved in a polyethylene sample absorbed a vapor of TEMPO radical as an electron spin source. We recently applied this technique to silica-filled SBR rubber, which is used for tread rubber of fuel-efficient tires. Finally, we successfully evaluated silica particles' dispersion state precisely, which is supposed to have great effect on tire's fuel efficiency.
Yamaguchi, Daisuke; Miyamoto, Nobuyoshi*; Nakato, Teruyuki*; Koizumi, Satoshi*; Ota, Noboru*; Yagi, Naoto*; Hashimoto, Takeji; Kawakatsu, Toshihiro
no journal, ,
The line shape of the scattering peaks from the layered phase of colloidal plate-like particles, which consist of niobate single layer crystal (often referred as "nanosheet"), was intensively examined in this study and a distinct anisotropy was found for the power law behavior of the peak intensity with respect to the q
and q
directions. Namely, the power law exponent of the peak intensity for q-direction was nearly double of that for q-direction. This experimental piece of evidence was at least qualitatively in agreement with Caille s prediction. In this study, the Caille' s formula was numerically integrated and the two-dimensional calculated scattering pattern was obtained. The q-behavior of the calculated scattering pattern is naturally similar to those of theoretical analysis and obtained experimental data.
Noda, Yohei; Yamaguchi, Daisuke; Hashimoto, Takeji; Shamoto, Shinichi; Koizumi, Satoshi; Yuasa, Takeshi*; Tominaga, Tetsuo*; Sone, Takuo*
no journal, ,
We applied proton spin contrast variation technique to silica filled SBR rubber, which is widely used for a fuel-efficient tire. In this technique, vapor sorption of TEMPO radical as an electron spin source played an important role for achieving high degree of proton spin polarization. As a result, we successfully evaluated the dispersion state of silica particles, which is known to be a key factor for tire's fuel efficiency.
Yamaguchi, Daisuke; Miyamoto, Nobuyoshi*; Nakato, Teruyuki*; Koizumi, Satoshi*; Ota, Noboru*; Yagi, Naoto*; Hashimoto, Takeji; Kawakatsu, Toshihiro*
no journal, ,
A highly periodic morphology of liquid crystalline (LC) phase formed in the aqueous colloidal dispersions of charged plate-like particles of niobate nanosheets was investigated by small-angle scattering method. The scattering profile was examined by line shape analysis and compared with calculation based on the Caille's formula. Qualitatively, an agreement between the experimental data and calculation (or theory) was obtained for the anisotropic decay of the peak intensity between the radial direction and that of perpendicular to the radial direction. Further quantitative comparison is under progress.
Yamaguchi, Daisuke; Miyamoto, Nobuyoshi; Koizumi, Satoshi; Nakato, Teruyuki*; Mayama, Hiroyuki*; Tsujii, Kaoru*; Hashimoto, Takeji
no journal, ,
no abstracts in English
Koizumi, Satoshi; Hashimoto, Takeji; Iwase, Hiroki*; Yamaguchi, Daisuke
no journal, ,
no abstracts in English
