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Volume 18 (2008)
- Issue 4 Pages 191-
- Issue 3 Pages 138-
- Issue 2 Pages 76-
- Issue 1 Pages 2-
Volume 18, Issue 2
Displaying 1-8 of 8 articles from this issue
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Expectation of Neutron ScientistsTakahiro Hayashi2008 Volume 18 Issue 2 Pages 76-78
Published: April 21, 2008
Released on J-STAGE: January 27, 2011
JOURNAL FREE ACCESSJ-PARC is going to start its operation in the latter half of this fiscal year. It is one of the major topics among not only neutron science but also Japanese science and technology policy.This article describes a personal view on circumstances of the present neutron science and expectations of neutron science researchers to success the J-PARC project.View full abstractDownload PDF (2924K) -
Minoru Nakano2008 Volume 18 Issue 2 Pages 79-82
Published: April 21, 2008
Released on J-STAGE: January 27, 2011
JOURNAL FREE ACCESSWe applied a time-resolved small-angle neutron scattering (SANS) technique to the vesicle system of phospholipids to determine the lipid dynamics. This technique takes advantage of the large difference in the scattering length density between hydrogenated and deuterated lipids, and the exchange of these lipids between vesicles results in a decrease in the scattering intensity, which can be detected by time-resolved SANS measurements. Vesicles consisting of deuterated (D-LUV) or hydrogenated phospholipid (H-LUV) with a diameter of ca. 100nm were prepared using Tris-buffered saline of D2O/H2O mixture that has a mean scattering length density between D-LUV and H-LUV. The SANS intensity from the mixtures of D-LUV and H-LUV was reduced over time, and the observed kinetics could be explicitly represented by a simple model that includes two independent kinetic parameters, i. e., the rates of transbilayer and interbilayer exchange. In addition, these dynamics were found to depend strongly on acyl chain length of the lipids and the presence of cholesterol.View full abstractDownload PDF (3412K) -
Exploration of reinforcement mechanisms in tires by SANSMikihito Takenaka, Shotaro Nishitsuji, Naoya Amino, Yasuhiro Ishikawa, ...2008 Volume 18 Issue 2 Pages 83-86
Published: April 21, 2008
Released on J-STAGE: January 27, 2011
JOURNAL FREE ACCESSThe network structures in rubber containing silica particles have investigated with contrast variation small-angle neutron scattering (SANS) method. The contrast variation SANS for the rubber specimens swollen by the solvents having various scattering length densities yielded partial scattering functions: the scattering function for polymer-polymer correlation Spp (q), the scattering function for silica-silica correlation Sss(q), and the scattering function for polymer-silica correlation SPS(q). The analyses of the partial scattering functions explored the following features:(1) Silica particles form aggregates consisting of several silica particles, and (2) there are relatively dense polymer layers around silica aggregates. Several characteristic parameters are estimated from the analyses, such as the size of aggregates, the thickness of layers, the volume fractions of polymer of layers and matrix, and the correlation length of the matrix network. This result suggests that the contrast variation SANS is a powerful tool of the analyses of the structures of the rubber-filler systems.View full abstractDownload PDF (3660K) -
Takuya Ishikawa, Ichiro Tanaka, Nobuo Niimura2008 Volume 18 Issue 2 Pages 87-91
Published: April 21, 2008
Released on J-STAGE: January 27, 2011
JOURNAL FREE ACCESSProtonation is the key to elucidate a function of protein.Neutron crystallographic analysis is a powerful method that can observe the protonation states of amino acid residues in a protein molecule. However the neutron crystallographic technique was very difficult method, because of low flux neutron source mainly. Recently, a neutron imaging plate and an elastically bent perfect Si monochromator enabled neutron experiment. As the result, neutron structural biology has been progressed greatly in these ten years. In this report, we explain the various biological reactions affected by the protonation state on protein molecules by our studies on neutron crystallographic analysis. Furthermore, we also introduce our recent study on the protonation of cubic insulin molecule.View full abstractDownload PDF (8854K) -
Hiroyuki Kagi, Kazuki Komatsu, Hiroshi Arima2008 Volume 18 Issue 2 Pages 92-96
Published: April 21, 2008
Released on J-STAGE: January 27, 2011
JOURNAL FREE ACCESSIn this article, we overview the applications of neutron diffraction at high pressure to earth and planetary sciences. One of the main targets of mineralogy is to determine hydrogen position in hydrous minerals. Structures of hydrogen-bearing minerals and silicate melt at high pressure will contribute to understanding relationship between water and deep earth processes. Neutron is also a powerful tool to distinguish isoelectronic ions in minerals. To achieve these new scientific applications, we are going to construct a beamline dedicating to earth and planetary sciences at high pressure in J-PARC. The preliminary design of the beamline will be introduced.View full abstractDownload PDF (1032K) -
Study suggests the existence of ferroelectric ice in the UniverseHiroshi Fukazawa2008 Volume 18 Issue 2 Pages 97-102
Published: April 21, 2008
Released on J-STAGE: January 27, 2011
JOURNAL FREE ACCESSWhether ice in the Universe exists as proton-ordered ices, is a question that has attracted scientific interest. Some ordered ices have ferroelectricity, and long range electrostatic forces caused by the ferroelectricity might be an important factor for planet formation. Our neutron study suggests that myriad big icy-bodies, which exist as dwarf planets and Kuiper Belt Object, consist of thick ferroelectric-ice surface and several inner layers of proton-ordered ices.View full abstractDownload PDF (9666K) -
Katsuhiro Kusaka2008 Volume 18 Issue 2 Pages 103-107
Published: April 21, 2008
Released on J-STAGE: January 27, 2011
JOURNAL FREE ACCESSIbaraki biological crystal diffractometer (iBIX) is under construction at next generation pulse neutron source (Materials and Life science Facility, BL03) in J-PARC. The diffractometer is designed to cover the sample crystals which have their cell edges up to around 150Å, and to realize the efficiency of measurement which is more than 100 times larger than the present high performance diffractometers, BIX-3 and BIX-4 in JRR-3 reactor in JAEA. In this paper, the current status of the construction of iBIX will be reported with latest diffractometer design determined by using computer simulation.View full abstractDownload PDF (9488K) -
[in Japanese]2008 Volume 18 Issue 2 Pages 108-110
Published: April 21, 2008
Released on J-STAGE: January 27, 2011
JOURNAL FREE ACCESSDownload PDF (559K)
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