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Journal Articles

Accurate structure analyses of polymer crystals on the basis of wide-angle X-ray and neutron diffractions

Tashiro, Koji*; Hanesaka, Makoto*; Yamamoto, Hiroko*; Wasanasuk, K.*; Jayaratri, P.*; Yoshizawa, Yoshinori*; Tanaka, Ichiro*; Niimura, Nobuo*; Kusaka, Katsuhiro*; Hosoya, Takaaki*; et al.

Kobunshi Rombunshu, 71(11), p.508 - 526, 2014/11

 Times Cited Count:6 Percentile:22.47(Polymer Science)

The crystal structure analysis of various polymer substances has been reviewed on the basis of wide-angle high-energy X-ray and neutron diffraction data. The progress in structural analytical techniques of polymer crystals have been reviewed at first. The structural models proposed so far were reinvestigated and new models have been proposed for various kinds of polymer crystals including polyethylene, poly(vinyl alcohol), poly(lactic acid) and its stereocomplex etc. The hydrogen atomic positions were also clarified by the quantitative analysis of wide-angle neutron diffraction data, from which the physical properties of polymer crystals have been evaluated theoretically. The bonded electron density distribution has been estimated for a polydiacetylene single crystal on the basis of the so-called X-N method or by the combination of structural information derived from X-ray and neutron diffraction data analysis. Some comments have been added about future developments in the field of structure-property relationship determination.

Journal Articles

Crystal structure analysis of poly(L-lactic acid) $$alpha$$ form on the basis of the 2-dimensional wide-angle synchrotron X-ray and neutron diffraction measurements

Wasanasuk, K.*; Tashiro, Koji*; Hanesaka, Makoto*; Ohara, Takashi*; Kurihara, Kazuo; Kuroki, Ryota; Tamada, Taro; Ozeki, Tomoji*; Kanamoto, Tetsuo*

Macromolecules, 44(16), p.6441 - 6452, 2011/07

 Times Cited Count:174 Percentile:98.62(Polymer Science)

The crystal structure of poly(L-lactic acid) (PLLA) $${alpha}$$ form has been analyzed in detail by utilizing the 2-dimensional wideangle X-ray (WAXD) and neutron diffraction (WAND) data measured for the ultradrawn sample. The WAXD data were collected using a synchrotron-sourced high-energy X-ray beam of wavelength 0.328${AA}$ at SPring-8 and the WAND data were measured using a neutron beam of wavelength 1.510${AA}$ with a BIX-3 detector at JRR-3, JAEA. The initial crystal structure model was extracted successfully by a direct method under the assumption of the space group ${it P}$2$$_{1}$$2$$_{1}$$2$$_{1}$$ using about 700 X-ray reflections observed at -150$$^{circ}$$C. The crystal structure model obtained by the direct method was refined so that the best agreement between the observed and calculated integrated intensities was obtained or the reliability factor (${it R}$) became minimal: ${it R}$ was 18.2% at -150$$^{circ}$$C and 23.2% at 25$$^{circ}$$C. The obtained chain conformation took the distorted (10/3) helical form with 2$$_{1}$$ helical symmetry along the chain axis. However, the symmetrically forbidden reflections were detected in a series of the 00l reflections, requiring us to erase the 2$$_{1}$$ screw symmetry along the molecular chain. By assuming the space group symmetry ${it P}$2$$_{1}$$, the structural refinement was made furthermore and the finally obtained R factor was 19.3% at -150$$^{circ}$$C and 19.4% at 25$$^{circ}$$C. This refined model was found to reproduce the observed reflection profiles well for all the layer lines. The X-ray-analyzed crystal structure was transferred to the WAND data analysis to determine the hydrogen atomic positions. The ${it R}$ factor was 23.0% for the 92 observed reflections at 25$$^{circ}$$C. The agreement between the observed and calculated layer line profiles was good.

Journal Articles

Structural refinement and extraction of hydrogen atomic positions in polyoxymethylene crystal based on the first successful measurements of 2-dimensional high-energy synchrotron X-ray diffraction and wide-angle neutron diffraction patterns of hydrogenated and deuterated species

Tashiro, Koji*; Hanesaka, Makoto*; Ohara, Takashi; Ozeki, Tomoji*; Kitano, Toshiaki*; Nishu, Takashi*; Kurihara, Kazuo; Tamada, Taro; Kuroki, Ryota; Fujiwara, Satoru; et al.

Polymer Journal, 39(12), p.1253 - 1273, 2007/12

 Times Cited Count:18 Percentile:49.77(Polymer Science)

no abstracts in English

Oral presentation

Current status of the neutron biological diffractometer in J-PARC

Tanaka, Ichiro*; Ohara, Takashi; Kurihara, Kazuo; Kusaka, Katsuhiro; Ozeki, Tomoji*; Niimura, Nobuo*

no journal, , 

Ibaraki Prefectural Government in Japan has started to construct a neutron diffractometer for biological macromolecules for industrial use at J-PARC. The diffractometer is designed to cover the sample crystals which have their cell edges less than 135 ${AA}$. It is expected to measure 100 samples per year if they have 2mm$$^{3}$$ in crystal volume. The efficiency is more than 50 times larger than the present high performance diffractometers, BIX-3 and BIX-4 in JRR-3 reactor, in JAERI. To realize this performance, three important and key items should be developed; an detector, neutron optics, and a software in data reduction. The current status of these developments will be reported with the latest parameters of this diffractometer.

Oral presentation

Ibaraki biological crystal diffractometer in J-PARC (BIX-P1); Optimization of design parameters

Kusaka, Katsuhiro; Ohara, Takashi; Tanaka, Ichiro*; Niimura, Nobuo*; Ozeki, Tomoji*; Kurihara, Kazuo; Aizawa, Kazuya; Morii, Yukio; Arai, Masatoshi; Ebata, Kazuhiro*; et al.

no journal, , 

The TOF neutron biological diffractometer in J-PARC proposed by Ibaraki prefectural government is designed to cover the samples have their cell edges up to 135A, and to realize the efficiency is more than 50 times larger than the present high performance diffractometer, BIX-4. To achieve this performance, the diffractometer will be installed on a coupled moderator has more intense peak but wider pulse shape. The overlapping of Bragg spots along the time-axis expected should be considered for the determination of optic parameters and it is necessary to de-convolute the overlapped spots with higher accuracy. The original simulation programs of TOF diffraction data were developed to obtain information of spot-overlapping, completeness of Bragg spots and spot profiles along time-axis. In this paper, the consideration of important designed parameters focused on biological macromolecular and the strategy of de-convoluting overlapped spots will be reported based on the simulation results.

Oral presentation

Design of the neutron optics for Ibaraki biomolecular diffractometer

Ohara, Takashi; Kurihara, Kazuo; Kusaka, Katsuhiro; Hosoya, Takaaki; Tanaka, Ichiro*; Niimura, Nobuo*; Ozeki, Tomoji*; Aizawa, Kazuya; Morii, Yukio; Arai, Masatoshi; et al.

no journal, , 

no abstracts in English

Oral presentation

Current status of IBARAKI biological diffractometer in J-PARC; Optimization of design parameters

Kusaka, Katsuhiro; Ohara, Takashi; Tanaka, Ichiro*; Niimura, Nobuo*; Kurihara, Kazuo; Hosoya, Takaaki; Ozeki, Tomoji*; Aizawa, Kazuya; Morii, Yukio; Arai, Masatoshi; et al.

no journal, , 

Ibaraki prefecture has started to construct IBARAKI biological crystal diffractometer for industrial use at MLF, J-PARC. It is designed to achieve the efficiency which is more than 50 times larger than the present high performance diffractometer BIX-4. To realize this performance, the diffractometer will be installed on a coupled moderator has more intense peak but wider pulse shape than a decoupled one. It is expected that some neighbor Bragg spots will overlap partially each other along the time axis. The overlapping of Bragg spots should be considered for optimization of design parameters and it is necessary to de-convolute the overlapped spots. The three original simulation programs of TOF diffraction data with designed parameters of the diffractometer were developed to obtain information of spot-overlapping, completeness of Bragg spots and spot profiles along the time axis. The consideration of important designed parameters will be reported based on the simulation results.

Oral presentation

Optimization of designparameters for Ibaraki Biological diffractometer in J-PARC by simulations of TOF diffraction data

Kusaka, Katsuhiro; Ohara, Takashi; Tanaka, Ichiro*; Niimura, Nobuo*; Kurihara, Kazuo; Hosoya, Takaaki; Ozeki, Tomoji*; Aizawa, Kazuya; Morii, Yukio; Arai, Masatoshi; et al.

no journal, , 

no abstracts in English

Oral presentation

Current status of IBARAKI biological diffractometer in J-PARC; Design of the neutron optics

Ohara, Takashi; Kurihara, Kazuo; Kusaka, Katsuhiro; Hosoya, Takaaki; Tanaka, Ichiro*; Niimura, Nobuo*; Ozeki, Tomoji*; Aizawa, Kazuya; Morii, Yukio; Arai, Masatoshi; et al.

no journal, , 

Ibaraki Prefectural Government in Japan has started to construct a TOF single crystal neutron diffractometer for biological macromolecules for industrial use at J-PARC. For this diffractometer, design of an efficient neutron transportation system is important because this diffractometer has 40m source-sample distance. Recently, we designed a supermirror neutron guide which can transport 0.7-3.8 Angstrom neutron efficiently. The total length of the mirror section is 25m. At the first 17m, the mirror has curvature (R=4300m) for horizontal direction in order to remove high-energy neutron and $$gamma$$ ray. Simultaneously, all of the mirror section has tapered angle for vertical direction in order to reduce the frequency of neutron reflection at the surface of the supermirror. The neutron flux and profile at the sample position was calculated by Monte Carlo simulation softwares, McStas and IDEAS and compared with a curved, non-tapered guide we had designed previously. In result, the new supermirror system has 2 times gain for 0.7 Angstrom neutron and 1.5 times for 1.5 Angstrom neutron, and the beam profile at the sample position has a rectangular shape.

Oral presentation

Current status of IBARAKI biological diffractometer in J-PARC; Detector configuration and data reduction

Kusaka, Katsuhiro; Ohara, Takashi; Tanaka, Ichiro*; Niimura, Nobuo*; Kurihara, Kazuo; Hosoya, Takaaki; Ozeki, Tomoji*; Aizawa, Kazuya; Morii, Yukio; Arai, Masatoshi; et al.

no journal, , 

Ibaraki prefecture has started to construct IBARAKI biological crystal diffractometer for industrial use at MLF, J-PARC. It is designed to achieve the efficiency which is more than 50 times larger than the present high performance diffractometer BIX-4. To realize this performance, the diffractometer will be installed on a coupled moderator has more intense peak but wider pulse shape than a decoupled one. It is expected that some neighbor Bragg spots will overlap partially each other along the time axis. We should develop the data reduction software system for the diffractometer including the program of peak de-convolution with fast algorism. The detector configuration should be also important to realize high performance for measurement speed and data accuracy. The strategy of data collection, the strategy of de-convoluting overlapped Bragg spots and its validity will be reported based on the results of the simulations with the original programs.

Oral presentation

Current status of IBARAKI biological crystal diffractometer in J-PARC

Tanaka, Ichiro*; Ohara, Takashi; Kurihara, Kazuo; Kusaka, Katsuhiro*; Hosoya, Takaaki; Tomoyori, Katsuaki*; Niimura, Nobuo*; Ozeki, Tomoji*; Aizawa, Kazuya; Arai, Masatoshi; et al.

no journal, , 

IBARAKI Biological Crystal Diffractometer is a new single-crystal neutron diffractometer for biological and chemical crystallography, and is now being constructed at J-PARC by Ibaraki Prefectural Government in Japan. This diffractometer is designed for the protein crystals with the cell dimension up to 135 ${AA}$. The measurement efficiency is more than 50 times larger than the present neutron diffractometer, BIX-3/BIX-4 in JRR-3 reactor at JAEA. To achieve this performance, we have selected a coupled moderator, and worked out the optimisation of the neutron guide tube. For the detector, a new wavelength-shifting-fiber type scintillation area detector system with high spatial (0.5-1.0 mm) and time (1ms-) resolution are in development.

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