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Journal Articles

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Kumada, Takayuki; Iwahara, Daisuke*

Isotope News, (798), p.26 - 27, 2025/04

no abstracts in English

Journal Articles

Kinetics of structural changes in starch retrogradation observed by simultaneous SANS/FTIR-ATR measurements

Hirata, Yoshinobu*; Kaneko, Fumitoshi*; Radulescu, A.*; Nishizu, Takahisa*; Katsuno, Nakako*; Imaizumi, Teppei*; Motokawa, Ryuhei; Kumada, Takayuki; Nakagawa, Hiroshi

Journal of Applied Glycoscience, 72(1), p.7201102_1 - 7201102_9, 2025/02

A simultaneous measurement system of SANS/FTIR-ATR was applied to record multiple structural changes in potato starch during retrogradation. In the SANS patterns, the shoulder-like peak becomes more pronounced with time. The peak intensity, Imax, which represents the amount of orderly arranged double helical structures, increased over time, showing that starch reassembled orderly on the nanoscale upon retrogradation. In the FTIR-ATR spectra, the increase of the ratio of absorptions at 1042 cm$$^{-1}$$ and 1016 cm$$^{-1}$$, indicating the amount of short-range ordered structure in starch increased during retrogradation. The time to obtain half of the equilibrium value for $$R_{1042/1016}$$ was larger than that for Imax. Changes in the short-range ordered structure of starch were observed to converge prior to changes in the nanostructure. These results indicate that the double-helix structures are initially formed by amylopectin side chains, and then these double-helical structures are arranged orderly.

Journal Articles

Nanostructure analysis of composite materials using polarized neutrons and polarized protons

Kumada, Takayuki

Shiki, 63, p.2 - 5, 2024/07

We introduce recent studies of spin-contrast-variation neutron scatterings, which utilizes the property that scattering power of neutron against proton remarkably depends on their relative spin directions, to reveal nanostructure of composite materials.

Journal Articles

Low-background ultrahigh-purity aluminium window for small-angle neutron scattering using monochromatic cold neutrons

Kumada, Takayuki; Motokawa, Ryuhei; Iwase, Hiroki*

Journal of Applied Crystallography, 57(Part 3), p.728 - 733, 2024/06

 Times Cited Count:2 Percentile:55.63(Chemistry, Multidisciplinary)

Journal Articles

Analyses of hierarchical structures in SBR rubber by using contrast-variation SANS; Effects of a silane coupling agent

Nakanishi, Yohei*; Shibata, Motoki*; Sawada, Satoshi*; Kondo, Hiroaki*; Motokawa, Ryuhei; Kumada, Takayuki; Yamamoto, Katsuhiro*; Mita, Kazuki*; Miyazaki, Tsukasa*; Takenaka, Mikihito*

Polymer, 306, p.127209_1 - 127209_7, 2024/06

 Times Cited Count:2 Percentile:56.40(Polymer Science)

Journal Articles

Nanometer-thick crystalline ice plates in rapidly-frozen glucose solution observed by spin-contrast-variation small-angle neutron scattering

Kumada, Takayuki; Nakagawa, Hiroshi; Miura, Daisuke; Sekine, Yurina; Motokawa, Ryuhei; Hiroi, Kosuke; Inamura, Yasuhiro; Oku, Takayuki; Oishi, Kazuki*; Morikawa, Toshiaki*; et al.

Hamon, 34(2), p.50 - 53, 2024/05

Spin-contrast-variation (SCV) small-angle neutron scattering (SANS) enabled us to determine structure of nano-ice crystals that were generated in rapidly frozen sugar solution. In the frozen glucose solution, we found that the nano-ice crystals formed a planar structure with a radius larger than several tens of nanometers and a thickness of 2-3 nm, which was close to the critical nucleation size of ice crystals in supercooled water. This result suggests that the glucose molecules were preferentially bound to a specific face of nano-ice crystals, and then blocked the crystal growth perpendicular to that face.

Journal Articles

Interpenetration of rubber and silane coupling agent on an inorganic substrate revealed by spin-contrast-variation neutron reflectivity

Kumada, Takayuki; Iwahara, Daisuke*; Nishitsuji, Shotaro*; Akutsu, Kazuhiro*; Miura, Daisuke; Motokawa, Ryuhei; Sugita, Tsuyoshi; Torikai, Naoya*; Amino, Naoya*; Oku, Takayuki; et al.

Journal of Physical Chemistry C, 128(21), p.8797 - 8802, 2024/05

 Times Cited Count:0 Percentile:0.00(Chemistry, Physical)

We elucidated the entanglement of polybutadiene and silane coupling agent (SCA) molecules bound to Si substrates using spin-contrast-variation (SCV) neutron reflectivity (NR). In an annealed integral blend film of polybutadiene and SCA, a SCA layer generated on the Si substrate was composed of 70 vol. percent SCA molecules extended perpendicularly from the silicon substrate and entangled with 30 vol. percent polybutadiene molecules. By contrast, in an SCA-precoated polybutadiene film, the SCA-precoated layer is composed of densely packed SCA molecules forming crystal-like structure, and thus did not become entangled with the postcoated polybutadiene molecules. This poor entanglement resulted in poor binding between polybutadiene and Si substrate.

Journal Articles

New standard for low temperature sample environment at JAEA/JRR-3

Kaneko, Koji; Tabata, Chihiro; Hagihara, Masato; Yamauchi, Hiroki; Oba, Yojiro; Kumada, Takayuki; Kubota, Masato; Kojima, Yuki*; Nabatame, Nozomi; Sasaki, Miki; et al.

JPS Conference Proceedings (Internet), 41, p.011015_1 - 011015_6, 2024/03

Journal Articles

Upgrade of the small-angle neutron scattering diffractometer SANS-J at JRR-3

Kumada, Takayuki; Motokawa, Ryuhei; Oba, Yojiro; Nakagawa, Hiroshi; Sekine, Yurina; Micheau, C.; Ueda, Yuki; Sugita, Tsuyoshi; Birumachi, Atsushi; Sasaki, Miki; et al.

Journal of Applied Crystallography, 56(6), p.1776 - 1783, 2023/12

 Times Cited Count:16 Percentile:97.10(Chemistry, Multidisciplinary)

The combination of the existing position-sensitive photomultiplier and the $$^{3}$$He main detector with focusing devices, and the newly installed front detectors in SANS-J at JRR-3 covers small-angle neutron scattering signals in the range of the magnitude of the scattering vector Q from 0.002 to 6 nm-1 gaplessly with three standard device layouts. The installation of the front detector and a graphical user interface system largely improved the usability of SANS-J.

Journal Articles

Structural changes of polystyrene particles in subcritical and supercritical water revealed by in situ small-angle neutron scattering

Shibata, Motoki*; Nakanishi, Yohei*; Abe, Jun*; Arima, Hiroshi*; Iwase, Hiroki*; Shibayama, Mitsuhiro*; Motokawa, Ryuhei; Kumada, Takayuki; Takata, Shinichi; Yamamoto, Katsuhiro*; et al.

Polymer Journal, 55(11), p.1165 - 1170, 2023/11

 Times Cited Count:2 Percentile:19.24(Polymer Science)

Journal Articles

Polarized neutrons observed nanometer-thick crystalline ice plates in frozen glucose solution

Kumada, Takayuki; Nakagawa, Hiroshi; Miura, Daisuke; Sekine, Yurina; Motokawa, Ryuhei; Hiroi, Kosuke; Inamura, Yasuhiro; Oku, Takayuki; Oishi, Kazuki*; Morikawa, Toshiaki*; et al.

Journal of Physical Chemistry Letters (Internet), 14(34), p.7638 - 7643, 2023/08

 Times Cited Count:0 Percentile:0.00(Chemistry, Physical)

The structure of nano-ice crystals in rapidly frozen glucose solution was elucidated by using spin-contrast-variation small-angle neutron scattering, which distinguishes the nano-ice crystal signal from the frozen amorphous solution signal by the polarization-dependent neutron scattering. The analysis revealed that the nano-ice crystals form a planar structure with a diameter exceeding tens of nanometers and a thickness of 1 nm, which is close to the critical nucleation size. This result suggests that the glucose molecules are preferentially bound to a specific face of nano-ice crystals, and then block the crystal growth perpendicular to that face.

Journal Articles

Heterogeneous aggregation of humic acids studied by small-angle neutron and X-ray scattering

Saito, Takumi*; Motokawa, Ryuhei; Okubo, Takahiro*; Miura, Daisuke*; Kumada, Takayuki

Environmental Science & Technology, 57(26), p.9802 - 9810, 2023/07

 Times Cited Count:1 Percentile:10.09(Engineering, Environmental)

Journal Articles

Structure analysis of asymmetric interface using spin-contrast-variation neutron reflectometry

Kumada, Takayuki; Miura, Daisuke*; Akutsu, Kazuhiro*; Oku, Takayuki; Torikai, Naoya*; Niizeki, Tomotake*

Hamon, 32(4), p.165 - 168, 2022/11

We demonstrated the advantage of spin-contrast-variation neutron reflectometry on the structure analysis of buried interface between resin and porous silica layers. The interface structure was not reproduced by the normal Gaussian model, but by the asymmetric interface model where crosslinked polymer chains neither permeate the pore nor follow the surface roughness of the silica layer.

Journal Articles

Structure analysis of a buried interface between organic and porous inorganic layers using spin-contrast-variation neutron reflectivity

Kumada, Takayuki; Miura, Daisuke*; Akutsu, Kazuhiro*; Oishi, Kazuki*; Morikawa, Toshiaki*; Kawamura, Yukihiko*; Suzuki, Junichi*; Oku, Takayuki; Torikai, Naoya*; Niizeki, Tomotake*

Journal of Applied Crystallography, 55(5), p.1147 - 1153, 2022/10

AA2021-0903.pdf:1.06MB

 Times Cited Count:2 Percentile:30.55(Chemistry, Multidisciplinary)

Spin-contrast-variation neutron reflectivity obtains multiple reflectivity curves from a single sample and a single beam source. We used the strong point of the technique to reveal that, although methylated-perhydropolysilazane-derived silica layer has a higher porosity near the interface with acrylic urethane resin, the resin did not permeate the pore network.

Journal Articles

Mass-resolved momentum imaging of three dichloroethylene isomers by femtosecond laser-induced coulomb explosion

Wada, Yoriko*; Akagi, Hiroshi*; Kumada, Takayuki; Itakura, Ryuji*; Wakabayashi, Tomonari*

Photochem (Internet), 2(3), p.798 - 809, 2022/09

Coulomb explosion experiments using 60 fs laser pulses were conducted for structural characterization of three dichloroethylene isomers. Under laser intensity at 1.8 $$times$$ 10$$^{14}$$ W/cm$$^2$$, mass-resolved momentum imaging (MRMI) for selected fragment ions of $$^{35}$$Cl$$^+$$ and C$$^{2+}$$ revealed different patterns for the three isomers. The C$${2+}$$ ion fragmented from multiply charged trans-1,2-DCE was forced to leave perpendicularly to the direction of the laser polarization, due to recoil forces from adjacent cations. In contrast, the fast ions of C$${2+}$$ from cis-1,2-DCE exhibited an isotropic distribution, whereas the fast ions of C$${2+}$$ from 1,1-DCE recoiled along the laser polarization together with the slow C$${2+}$$ ions, and thereby distinction of the three isomers was demonstrated. Coulomb explosion occurs predominantly at specific orientation, which is useful for potential applications of MRMI analysis to molecular structure assays.

Journal Articles

Development of spin-contrast-variation neutron powder diffractometry for extracting the structure factor of hydrogen atoms

Miura, Daisuke*; Kumada, Takayuki; Sekine, Yurina; Oku, Takayuki; Takata, Shinichi; Hiroi, Kosuke; Iwata, Takahiro*

J-PARC 22-02; J-PARC MLF Annual Report 2021, p.6 - 7, 2022/03

We carried out spin contrast variation neutron powder diffractometry of glutamic acid crystal. The diffraction peak intensities varied as a function of proton polarization. We extracted the structure factor of hydrogen atoms from the variation of peak intensities.

Journal Articles

Nanoscopic structure of borosilicate glass with additives for nuclear waste vitrification

Motokawa, Ryuhei; Kaneko, Koji; Oba, Yojiro; Nagai, Takayuki; Okamoto, Yoshihiro; Kobayashi, Taishi*; Kumada, Takayuki; Heller, W. T.*

Journal of Non-Crystalline Solids, 578, p.121352_1 - 121352_7, 2022/02

 Times Cited Count:4 Percentile:19.81(Materials Science, Ceramics)

Journal Articles

Extraction of hydrogen location in molecular crystals in spin-contrast-variation neutron powder diffractometry

Miura, Daisuke*; Kumada, Takayuki; Iwata, Takahiro*

Nihon Kessho Gakkai-Shi, 63(4), p.287 - 293, 2021/12

We have developed the spin-contrast-variation neutron powder diffractometry to observe hydrogen atoms in a crystalline sample by polarized neutron and polarized proton in the crystal. L-glutamic acid crystals were dispersed in a deuterated polystyrene matrix containing a polarizing agent. The intensities of the diffraction peaks of the sample changed according to the proton polarization. The spin-contrast-variation neutron powder diffractometry can extract diffraction from hydrogen atoms because of the variation of peak intensities as a function of the proton polarization. This technique is expected to enable analyses of the structures of hydrogen-containing materials that are difficult to determine with conventional powder diffractometry.

Journal Articles

Development of spin-contrast-variation neutron powder diffractometry for extracting the structure factor of hydrogen atoms

Miura, Daisuke*; Kumada, Takayuki; Sekine, Yurina; Motokawa, Ryuhei; Nakagawa, Hiroshi; Oba, Yojiro; Ohara, Takashi; Takata, Shinichi; Hiroi, Kosuke; Morikawa, Toshiaki*; et al.

Journal of Applied Crystallography, 54(2), p.454 - 460, 2021/04

AA2020-0724.pdf:2.05MB

 Times Cited Count:1 Percentile:13.30(Chemistry, Multidisciplinary)

We developed a spin-contrast-variation neutron powder diffractometry technique that extracts the structure factor of hydrogen atoms, namely, the contribution of hydrogen atoms to a crystal structure factor. Crystals of L-glutamic acid were dispersed in a dpolystyrene matrix containing 4-methacryloyloxy-2,2,6,6,-tetramethyl-1-piperidinyloxy (TEMPO methacrylate) to polarize their proton spins dynamically. The intensities of the diffraction peaks of the sample changed according to the proton polarization, and the structure factor of the hydrogen atoms was extracted from the proton-polarization dependent intensities. This technique is expected to enable analyses of the structures of hydrogen-containing materials that are difficult to determine with conventional powder diffractometry.

Journal Articles

Introduction to SANS-J and PNO

Kumada, Takayuki; Motokawa, Ryuhei; Nakagawa, Hiroshi; Oba, Yojiro; Sekine, Yurina

Hamon, 31(1), p.5 - 6, 2021/02

no abstracts in English

228 (Records 1-20 displayed on this page)