Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
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：14 Percentile：48.07(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：21 Percentile：74.77(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：33 Percentile：88.88(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：28 Percentile：63.85(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
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.
Yamaguchi, Daisuke; Mayama, Hiroyuki*; Koizumi, Satoshi; Tsujii, Kaoru*; Hashimoto, Takeji
European Physical Journal B, 63(2), p.153 - 163, 2008/05
Times Cited Count：12 Percentile：48.27(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.
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：55 Percentile：85.89(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：112 Percentile：94.98(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：86.13(Chemistry, Multidisciplinary)no abstracts in English
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：39 Percentile：80.57(Physics, Condensed Matter)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：56.14(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.
Yamaguchi, Daisuke; Miyamoto, Nobuyoshi; Koizumi, Satoshi; Nakato, Teruyuki*; Hashimoto, Takeji
no journal, ,
The exfoliated KNb
O
nanosheets in the aqueous solutions were observed by (ultra-) small-angle neutron and X-ray scattering (SANS, USANS and USAXS). A comprehensive measurement revealed the assembled structure of nanosheets in wide range of q, from 310 nm to 1 nm, where q is the magnitude of scattering vector. The details of liquid crystalline structure formed by [NbO]
nanosheets, which was reflected on the scattering at higher q region (
310 (nm)), largely depend on the nanosheet lateral dimension or its volume fraction. On the other hand, at lower q region (110 (nm)), the scattering profile shows a power law scattering of which index is -2.5 regardless of the nanosheet lateral dimension or its volume fraction, suggesting that at large scale nanosheets take similar mass fractal distribution.
Yamaguchi, Daisuke; Mayama, Hiroyuki*; Koizumi, Satoshi; Tsujii, Kaoru*; Hashimoto, Takeji
no journal, ,
The fractal dimensions of specific porous silica materials were investigated by ultra-small-angle neutron scattering (USANS). 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. The fractal dimension of the pores was changeable by the compression of the AKD mould at different ratio (hereafter designated as r) before the mould was filled with a TMOS solution, which turned to silica matrix, and three specimens, of which r = 1, 2, and 3, were prepared. USANS measurements brought us wide-q observations of the specimens, in the q scale of more than three orders of magnitude, and made it possible to accurate evaluation of the fractal dimension. The resultant mass-fractal dimensions for the specimens of r = 1, 2, and 3 were 2.98, 2.74, and 2.67, respectively.
Yamaguchi, Daisuke; Miyamoto, Nobuyoshi; Koizumi, Satoshi; Nakato, Teruyuki*; Mayama, Hiroyuki*; Tsujii, Kaoru*; Hashimoto, Takeji
no journal, ,
no abstracts in English
Koizumi, Satoshi; Kondo, Tetsuo*; Tomita, Yoko*; Iwase, Hiroki; Yamaguchi, Daisuke; Hashimoto, Takeji
no journal, ,
no abstracts in English
Yamaguchi, Daisuke; Miyamoto, Nobuyoshi*; Koizumi, Satoshi; Hashimoto, Takeji; Nakato, Teruyuki*; Mayama, Hiroyuki*; Tsujii, Kaoru*
no journal, ,
The hierarchical structures composed of two-dimensional particles were observed via ultra-small-angle scattering method. We have investigated two systems: (1) exfoliated KNbO nanosheet colloidal dispersion, (2) porous silica fabricated from alkylketene dimer template. Although the physical and chemical structures and properties are largely different in these two systems, a similar point to them is regarded as below. The thickness of the constituent particles is ranging from a few nanometers to several tens of nanometers. Various fractal-like power-law scattering were obtained in the ultra-small angle scattering region reflecting the difference in the self-assembly of the particles.
Yamaguchi, Daisuke; Miyamoto, Nobuyoshi; Koizumi, Satoshi; Nakato, Teruyuki*; Hashimoto, Takeji
no journal, ,
no abstracts in English
