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Yagi, Naoto*; Matsuo, Tatsuhito; Ota, Noboru*
Journal of Synchrotron Radiation, 19(4), p.574 - 578, 2012/07
Times Cited Count：1 Percentile：7.11(Instruments & Instrumentation)X-ray diffraction patterns were recorded from isolated single rod outer segments of frog. The outer segments in Ringer's solution were exposed to a 6 
m microbeam (15 keV) at the BL40XU beamline, SPring-8. The diffraction pattern demonstrated a remarkable regularity in the stacking and flatness of the disk membranes. The electron density profile calculated from the intensity of up to tenth-order reflections showed a pair of bilayers that comprise a disk membrane. The structure of the disk membrane and the changes in the profile on swelling generally agreed with previous reports. Radiation damage was significant with an irradiation of 5 
10
Gy which is much lower than the known damaging dose on proteins at the liquid-nitrogen temperature.
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：75.06(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 = 2.510
. (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.
C targets on Au backingsSugai, Isao*; Takeda, Yasuhiro*; Kawakami, Hirokane*; Ota, Naoto*; Makii, Hiroyuki; Miyatake, Hiroari*
Nuclear Instruments and Methods in Physics Research A, 655(1), p.24 - 33, 2011/11
Times Cited Count：3 Percentile：26.67(Instruments & Instrumentation)Inoue, Naoko; Hori, Keiichiro; Dosho, Hisaharu; Ota, Kiyokazu*; Otsuka, Naoto; Aso, Ryoji; Senzaki, Masao
Proceedings of INMM 47th Annual Meeting (CD-ROM), 6 Pages, 2006/00
no abstracts in English
Kurasaki, Takaaki*; Dosho, Hisaharu; Ota, Kiyokazu*; Hori, Keiichiro; Kuribayashi, Toshihiro; Otsuka, Naoto
Proceedings of INMM 47th Annual Meeting (CD-ROM), 8 Pages, 2006/00
no abstracts in English
; ; ; *; ; Tanaka, Kichizo; *;
JAERI-M 5502, 17 Pages, 1973/12
no abstracts in English
Nb
O
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.
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.
