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Hatakeyama, Nozomi*; Miura, Ryuji*; Miyamoto, Naoto*; Miyamoto, Akira*; Ara, Kuniaki; Shimoyama, Kazuhito; Kato, Atsushi; Yamamoto, Tomohiko
Journal of Computer Chemistry, Japan, 21(2), p.61 - 62, 2022/00
no abstracts in English
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：74.91(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.
Osawa, Hideaki; Ota, Kunio; Hama, Katsuhiro; Sawada, Atsushi; Takeuchi, Shinji; Amano, Kenji; Saegusa, Hiromitsu; Matsuoka, Toshiyuki; Miyamoto, Tetsuo; Toyoda, Gakuji; et al.
JAEA-Research 2008-085, 742 Pages, 2008/11
JAEA-Research-2008-085-1.pdf:26.22MBJAEA-Research-2008-085-2.pdf:16.64MBJAEA-Research-2008-085-3.pdf:28.27MB
This report shows the results the project for the establishment of comprehensive site characterization technology, entrusted from Natural Resources and Energy Agency, Ministry of Economy, Trade and Industry Natural Resources and Energy Agency in 2007.
Nishitani, Tomohiro; Nakanishi, Tsutomu*; Yamamoto, Masahiro*; Okumi, Shoji*; Furuta, Fumio*; Miyamoto, Masaharu*; Kuwahara, Makoto*; Yamamoto, Naoto*; Naniwa, Kenichi*; Watanabe, Osamu*; et al.
Journal of Applied Physics, 97(9), p.094907_1 - 094907_6, 2005/05
Times Cited Count：64 Percentile：87.28(Physics, Applied)no abstracts in English
Uehara, Tomoya*; Koike, Miho*; Nakata, Hideo*; Miyamoto, Shigehiko*; Motoishi, Shoji; Hashimoto, Kazuyuki; Oku, Naoto*; Nakayama, Morio*; Arano, Yasushi*
Nuclear Medicine and Biology, 30(3), p.327 - 334, 2003/04
Times Cited Count：20 Percentile：50.08(Radiology, Nuclear Medicine & Medical Imaging)no abstracts in English
Nb
O
nanosheetYamaguchi, Daisuke; Miyamoto, Nobuyoshi*; Koizumi, Satoshi; Nakato, Teruyuki*; Yagi, Naoto*; Hashimoto, Takeji
no journal, ,
Two new experimental evidences were obtained in lyotropic liquid crystalline (LC) phase behavior consisting of a model charged colloidal platelike particle system yielded from layered niobate crystal of KNbO. Firstly, the effect of mean lateral size (
) of the particle was examined at a constant volume fraction of the particle (
) where a LC phase coexisted with an isotropic (I) phase. The coexisting LC phase was abruptly transformed from nematic to lamellar (L) as was decreased. Secondly, the dependence of the interparticle distance (d) was examined along the I-L transition. In the coexistence region, d showed nearly the same value between those two phases and varied with , being out of the usual lever rule.
NbO nanosheetsYamaguchi, Daisuke; Miyamoto, Nobuyoshi*; Fujita, Takako*; Nakato, Teruyuki*; Koizumi, Satoshi; Yagi, Naoto*; Ota, Noboru*; Hashimoto, Takeji
no journal, ,
Formation of lyotropic liquid crystalline (LC) phase was observed on a charged colloidal platelike particle system yielded from layered niobate crystal of KNbO. Firstly, the effect of mean lateral size (D) of the particle was examined at a constant volume fraction of the particle (.fai.) where a LC phase coexisted with an isotropic (I) phase. The coexisting LC phase was distinctly transformed from nematic to lamellar (L) as D was diminished. Secondly, the .fai. dependence of the interparticle distance (d) was examined along the I-L transition. In the coexistence region, d varied with .fai. and held nearly the same value between I and L phases, apparently deviating from gas-liquid condensation-type phase separation.
Yamaguchi, Daisuke; Miyamoto, Nobuyoshi*; Fujita, Takako*; Nakato, Teruyuki*; Koizumi, Satoshi; Ota, Noboru*; Yagi, Naoto*; Hashimoto, Takeji
no journal, ,
The lyotropic lamellar phase in colloidal suspension has been well established in the recent work of the exfoliated inorganic phosphatoantimonate crystal. Here we report the other distinct lamellar phase formed in the colloidal suspension of hexaniobate "nanosheet", which is coexistent with an isotropic phase. This colloidal system clearly shows that not only the degree of orientational order but also that of positional order are quite different between upper isotropic phase and bottom lamellar phase. However, a definite interparticle correlation does exist in the isotropic phase and the difference in the mean interparticle distance (d) between lamellar and isotropic phases turned out rather small. All those pieces of experimental evidence suggest that the coexisting isotropic-lamellar phases is not attributed to the sedimentation of the nanosheet particles by the gravity but arisen as a result of ordering process of nanosheet particles by getting over the random thermal force of Brownian motion.
Yano, Tetsuji*; Akagi, Naoto*; Shibata, Shuichi*; Okita, Takeshi*; Matsuyama, Kanae*; Miyamoto, Shinya*; Amamoto, Ippei; Kofuji, Hirohide
no journal, ,
Surface structures of iron phosphate glasses (IPG) are investigated in order to know the origin of the high chemical durability using X-ray photoelectron spectroscopy. In this study, several IPG samples in which a part of iron oxide are replaced by other transition metal oxides are prepared and subjected to the chemical durability test. Surface structures are investigated before and after the durability test and the information on the structural changes are obtained.
Yamaguchi, Daisuke; Miyamoto, Nobuyoshi*; Fujita, Takako*; Nakato, Teruyuki*; Koizumi, Satoshi; Ota, Noboru*; Yagi, Naoto*; Hashimoto, Takeji*
no journal, ,
The lyotropic lamellar phase in colloidal suspension has been well established in the recent work of the exfoliated inorganic phosphatoantimonate crystal. Here we report the other distinct lamellar phase formed in the colloidal suspension of hexaniobate nanosheet, which is coexistent with an isotropic phase. It is clear that not only the degree of orientational order but also that of positional order are quite different between upper isotropic phase and bottom lamellar phase. However, a definite interparticle correlation does exist in the isotropic phase and the difference in the mean interparticle distance between lamellar and isotropic phases turned out rather small. All those pieces of experimental evidence suggest that the coexisting isotropic-lamellar phases is not attributed to the sedimentation of the nanosheet particles by the gravity but arisen as a result of ordering process of nanosheet particles by getting over the random thermal force of Brownian motion.
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.
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*; Nakato, Teruyuki*; Koizumi, Satoshi*; Ota, Noboru*; Yagi, Naoto*; Hashimoto, Takeji; Kawakatsu, Toshihiro
no journal, ,
Self-assembled structures of aqueous colloidal dispersions of niobate nanosheets having a uniform thickness of d = 1.6 nm and an average lateral dimension of L = 650 nm, hence an extremely large nominal aspect ratio (L/d) of 
400 were studied by micro-beam synchrotron small-angle X-ray scattering (SAXS). The results elucidated highly orientated, periodic layered liquid crystalline phase exhibiting a multiple-order scattering peaks. The line-profiles of the multiple-order peaks were analyzed in the directions both parallel and perpendicular to the one-dimensional stacks of the nanosheets for each order of the peaks. The results were compared with the formula based on harmonic approximation. An experimental problem associated with effects of orientation distributions of the stacks on the line profile analyses was quantitatively examined.
Sasaki, Shigemi*; Miyamoto, Atsushi*; Hosaka, Masahito*; Yamamoto, Naoto*; Kyo, Ayataro*; Kato, Masahiro*; Imazono, Takashi; Koike, Masato
no journal, ,
The phenomenon of higher harmonic radiation from a helical undulator carrying orbital angular momentum (OAM) attracts a great deal of attention because this novel property may be used as a new probe for synchrotron radiation science that would be performed in diffraction limited light source facilities. Although a diffraction limited VUV and X-ray sources do not yet exist, the 750 MeV UVSOR-III is already a diffraction limited light source in the UV region. In this ring, a tandem-aligned double-APPLE undulator system is installed. Using this set-up, we observed spiral interference patterns between two different harmonic radiations with a scanning fiber multi-channel spectrometer and a CCD camera placed at the end of BL1U beamline. By these measurements, various interference patterns such as single, double, and triple spirals were observed which concur with the theoretical prediction for every mode in the right or left circular polarization.
Hatakeyama, Nozomi*; Miura, Ryuji*; Suzuki, Ai*; Miyamoto, Naoto*; Miyamoto, Akira*; Ara, Kuniaki; Shimoyama, Kazuhito; Kato, Atsushi; Yamamoto, Tomohiko
no journal, ,
no abstracts in English
