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Journal Articles

Morphological reproductive characteristics of testes and fertilization capacity of cryopreserved sperm after the Fukushima accident in raccoon (${it Procyon lotor}$)

Komatsu, Kazuki*; Iwasaki, Tsugumi*; Murata, Kosuke*; Yamashiro, Hideaki*; Goh, V. S. T.*; Nakayama, Ryo*; Fujishima, Yohei*; Ono, Takumi*; Kino, Yasushi*; Shimizu, Yoshinaka*; et al.

Reproduction in Domestic Animals, 56(3), p.484 - 497, 2021/03

 Times Cited Count:6 Percentile:97.42(Agriculture, Dairy & Animal Science)

We have established an archive system of livestock and wild animals from the surrounding ex-evacuation zone. Wildlife within the alert zone have been exposed to low-dose-rate (LDR) radiation for a long and continuous time. In this study, we analysed the morphological characteristics of the testes and in vitro fertilization (IVF) capacity of cryopreserved sperm of raccoons from the ex-evacuation zone of the FDNPP accident. This study revealed that the chronic and LDR radiation exposure associated with the FDNPP accident had no adverse effect on the reproductive characteristics and functions of male raccoons.

Journal Articles

Conceptual study on parasitic low-energy RI beam production with in-flight separator BigRIPS and the first stopping examination for high-energy RI beams in the parasitic gas cell

Sonoda, Tetsu*; Katayama, Ichiro*; Wada, Michiharu*; Iimura, Hideki; Sonnenschein, V.*; Iimura, Shun*; Takamine, Aiko*; Rosenbusch, M.*; Kojima, Takao*; Ahn, D. S.*; et al.

Progress of Theoretical and Experimental Physics (Internet), 2019(11), p.113D02_1 - 113D02_12, 2019/11

AA2019-0315.pdf:1.37MB

 Times Cited Count:0 Percentile:0.01(Physics, Multidisciplinary)

An in-flight separator, BigRIPS, at RIBF in RIKEN provides each experiment with specific nuclides separated from many nuclides produced by projectile fragmentation or in-flight fission. In this process, nuclides other than separated ones are discarded on the slits in BigRIPS, although they include many nuclides interested from the view point of nuclear structure. In order to extract these nuclides for parasitic experiments, we are developing a method using laser ion-source (PALIS). A test experiment with $$^{78}$$Se beam from RIBF has been performed by using a gas cell set in BigRIPS. Unstable nuclides around $$^{67}$$Se were stopped in the gas cell in accordance with a calculation using LISE code. The stopping efficiency has been estimated to be about 30%. As a next step, we will establish the technique for extracting reaction products from the gas cell.

Journal Articles

Hierarchically self-organized dissipative structures of filler particles in poly(styrene-$$ran$$-butadiene) rubbers

Yamaguchi, Daisuke; Yuasa, Takeshi*; Sone, Takuo*; Tominaga, Tetsuo*; Noda, Yohei*; Koizumi, Satoshi*; Hashimoto, Takeji*

Macromolecules, 50(19), p.7739 - 7759, 2017/10

 Times Cited Count:8 Percentile:37.66(Polymer Science)

We elucidated the spatial distribution of filler particles in cross-linked poly(styrene-$$ran$$-butadiene) rubbers (SBR) developed under a typical fillers/rubbers compounding process as one of dissipative structures formed under a stress field imposed on the given system. The dispersion state of the fillers in SBR was clarified on the basis of hierarchical structures consisting of five structure levels. More specifically, it has the following characteristics depending on the specific interactions: Small, compact clusters build up compact mass-fractal structures, while large, loose clusters build up open mass-fractal structures.

Journal Articles

Contrast variation by dynamic nuclear polarization and time-of-flight small-angle neutron scattering, 1; Application to industrial multi-component nanocomposites

Noda, Yohei*; Koizumi, Satoshi*; Masui, Tomomi*; Mashita, Ryo*; Kishimoto, Hiromichi*; Yamaguchi, Daisuke; Kumada, Takayuki; Takata, Shinichi; Oishi, Kazuki*; Suzuki, Junichi*

Journal of Applied Crystallography, 49(6), p.2036 - 2045, 2016/12

 Times Cited Count:14 Percentile:74.72(Chemistry, Multidisciplinary)

Journal Articles

Dynamic nuclear polarization of electron-beam irradiated polyethylene by pairs of alkyl free radicals

Kumada, Takayuki; Noda, Yohei; Ishikawa, Norito

Journal of Magnetic Resonance, 218, p.59 - 65, 2012/05

 Times Cited Count:6 Percentile:37.12(Biochemical Research Methods)

We compared dynamic nuclear polarization (DNP) behavior of electron-beam irradiated polyethylene (e-PE) with that of TEMPO-doped polystyrene (T-PS). Although both T-PS had a sharp maximum in nuclear polarization at the concentration of free radicals of 2$$times$$10$$^{19}$$ spins cm$$^{-3}$$, that of e-PE depend much less. Growth and decay rates of polarization of e-PE linearly increased with increasing the radical concentration, whereas those rates of T-PS increased with square of radical concentration. We concluded that, not a pair of unspecified radicals accidentally located nearby, but a pair of alkyl radicals produced by the dissociation of C-H bond by an electron irradiation and the subsequent hydrogen abstraction reaction play an important role on DNP of e-PE.

Journal Articles

Inhomogeneous dynamic nuclear polarization of protons in a lamella-forming diblock copolymer investigated by a small-angle neutron scattering method

Noda, Yohei; Kumada, Takayuki; Hashimoto, Takeji; Koizumi, Satoshi

Journal of Applied Crystallography, 44(3), p.503 - 513, 2011/06

 Times Cited Count:13 Percentile:76.86(Chemistry, Multidisciplinary)

We measured small angle neutron scattering (SANS) for dynamically polarized block copolymer sample, one phase of which were selectively doped with radical. Dynamic nuclear polarization (DNP) caused the neutron scattering length of proton largely, as a result, the SANS intensity. By the analysis of the change of the SANS intensity, we found out the inhomogeneous distribution of the radical induced the inhomogeneous polarization (about 2% for the average polarization being 30%).

Journal Articles

Applications of $$^{3}$$He neutron spin filters on the small-angle neutron scattering spectrometer SANS-J-II

Sakaguchi, Yoshifumi; Kira, Hiroshi; Oku, Takayuki; Shinohara, Takenao; Suzuki, Junichi; Sakai, Kenji; Nakamura, Mitsutaka; Aizawa, Kazuya; Arai, Masatoshi; Noda, Yohei; et al.

Journal of Physics; Conference Series, 294(1), p.012017_1 - 012017_7, 2011/06

 Times Cited Count:2 Percentile:67.18

Journal Articles

Mesoscale spatial distribution of electron spins studied by time-resolved small-angle and ultrasmall-angle neutron scattering with dynamic nuclear polarization; A Case of 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) doped in high-density polyethylene

Kumada, Takayuki; Noda, Yohei; Koizumi, Satoshi; Hashimoto, Takeji

Journal of Chemical Physics, 133(5), p.054504_1 - 054504_7, 2010/08

 Times Cited Count:9 Percentile:31.04(Chemistry, Physical)

We carried out time-resolved small-angle neutron scattering studies of dynamically polarized high-density polyethylene (HDPE) doped with 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) persistent free radicals. We observed an enhancement of the scattering intensity by a factor of 100 in maximum after switching a microwave frequency. The enhancement was found to be due to concentration fluctuation of TEMPO, which generates heterogeneity of polarization with the length-scale of about 100 nm and scattering due to the heterogeneity. The length scale of the heterogeneity indicates that the TEMPO free radicals are localized more in non-fibrils but less in fibrils of HDPE.

Journal Articles

Anisotropic and inhomogeneous magnetic interactions observed in all-organic nitroxide radical liquid crystals

Uchida, Yoshiaki*; Suzuki, Katsuaki*; Tamura, Rui*; Ikuma, Naohiko*; Shimono, Satoshi*; Noda, Yohei; Yamauchi, Jun*

Journal of the American Chemical Society, 132(28), p.9746 - 9752, 2010/06

 Times Cited Count:48 Percentile:75.18(Chemistry, Multidisciplinary)

An anisotropic and inhomogeneous magnetic interaction (the average spin-spin interaction constant, $$bar{rm J}$$ $$>$$ 0) was observed in the various liquid crystalline (LC) phases of racemic and nonracemic all-organic radical LC compounds. We discussed how the LC superstructures induced the magnetic interaction to operate in the LC phases in terms of spin-spin dipole and exchange interactions by means of VT-EPR spectroscopy. The magnitude of the magnetic interaction depended on the type of LC phase, or the superstructure. Furthermore, these radical LC droplets floating on water were commonly attracted to a permanent magnet and moved freely under the influence of this magnet, whereas the crystallized particles of the same compounds never responded to the magnet. The response of the LC droplets to the magnet also varied depending on the type of LC phase, that is, the extent of the magnetic interaction.

Journal Articles

Dynamic nuclear polarization study of UV-irradiated butanol for hyperpolarized liquid NMR

Kumada, Takayuki; Noda, Yohei; Hashimoto, Takeji; Koizumi, Satoshi

Journal of Magnetic Resonance, 201(2), p.115 - 120, 2009/12

 Times Cited Count:6 Percentile:34.07(Biochemical Research Methods)

We have carried out a dynamic nuclear polarization (DNP) study of proton spins of UV-irradiated solid butanol containing phenol. By the aid of butyl free radicals produced by the photolysis, the butanol sample was dynamically polarized up to the polarization of 1.4% at 1.5 K and 1.2 T. Unlike persistent free radicals such as nitroxy and trityl free radicals commonly used for DNP, the butyl free radicals immediately decay by melting. We propose that free radicals produced by UV-photolysis are applicable to the DNP-enhanced hyperpolarized liquid-state NMR.

Journal Articles

Dynamic nuclear polarization system for the SANS-J-II spectrometer at JAEA

Kumada, Takayuki; Noda, Yohei; Hashimoto, Takeji; Koizumi, Satoshi

Physica B; Condensed Matter, 404(17), p.2637 - 2639, 2009/09

 Times Cited Count:11 Percentile:46.93(Physics, Condensed Matter)

We have developed dynamic nuclear polarization (DNP) system for SANS-J-II at the JRR-3 atomic research reactor at Japan Atomic Energy Agency. Our system is composed of superconducting magnet (3.3 Tesla), Gunn oscillator as a microwave source (94 GHz), and cryostat (1.2 K). We succeeded in polarizing polyethylene sample up to 0.32 and observing effects of polarization on SANS profile. We plan to use the DNP and SANS system in order to determine structure factors of multi-component systems.

Journal Articles

Small-angle neutron scattering study of dynamically polarized polyethylenes

Noda, Yohei; Kumada, Takayuki; Hashimoto, Takeji; Koizumi, Satoshi

Physica B; Condensed Matter, 404(17), p.2572 - 2574, 2009/09

 Times Cited Count:8 Percentile:38.1(Physics, Condensed Matter)

We polarized hydrogen nuclear spins of polyethylene samples, doped with organic radical (TEMPO), by use of a dynamic nuclear polarization (DNP) technique, in which the sample was irradiated by microwave (94 GHz) at 3.3 Tesla and 1.4 K. For the samples under the DNP state, we conducted small-angle scattering experiments with polarized neutrons. For the sample with low crystallinity (polarization: 32%), the shift of the incoherent scattering level was observed. For the sample with high crystallinity (polarization: 23%), the enhancement of the coherent scattering due to the crystalline structure was observed.

Journal Articles

Dynamic nuclear polarization of high- and low-crystallinity polyethylenes

Kumada, Takayuki; Noda, Yohei; Hashimoto, Takeji; Koizumi, Satoshi

Nuclear Instruments and Methods in Physics Research A, 606(3), p.669 - 674, 2009/07

 Times Cited Count:10 Percentile:59.1(Instruments & Instrumentation)

We carried out a DNP study of high (HPE) and low (LPE) crystallinity polyethylene films, which were doped with TEMPO. The proton polarization of 32% was obtained for LPE and 23% for HPE at 3.35 T and 1.4 K. We found by ESR study that TEMPO did not incorporated into the crystalline part, and was localized only at the amorphous part. We suggest that the smaller nuclear polarization for HPE is related to the localization of TEMPO in the smaller amorphous regions.

Journal Articles

Unusual intermolecular magnetic interaction observed in an all-organic radical liquid crystal

Uchida, Yoshiaki*; Ikuma, Naohiko*; Tamura, Rui*; Shimono, Satoshi*; Noda, Yohei; Yamauchi, Jun*; Aoki, Yoshio*; Nohira, Hiroyuki*

Journal of Materials Chemistry, 18(25), p.2950 - 2952, 2008/07

 Times Cited Count:39 Percentile:75.07(Chemistry, Physical)

We found out an unusual intermolecular magnetic interaction in the liquid-crystalline (LC) state of an all-organic radical compound on surface of water (73 $$^{circ}$$C); the magnetic interaction actually allows the LC droplet on water to be attracted by a weak permanent magnet, whereas the crystalline phase did not respond to the magnet.

Oral presentation

Small-angle neutron scattering and dynamic nuclear polarization studies on spa produced in irradiated solids

Kumada, Takayuki; Noda, Yohei; Hashimoto, Takeji; Koizumi, Satoshi

no journal, , 

We try to determine structure of spa produced by radiolysis of cryocrystals using small-angle neutron scattering (SANS) and dynamic nuclear polarization (DNP) system. In this presentation, we will talk about the principle of SANS and DNP system, idea to measure spa, and present status.

Oral presentation

Molecular orientation of chiral paramagnetic liquid crystals under electric and/or magnetic fields

Noda, Yohei; Koizumi, Satoshi; Hashimoto, Takeji; Shimono, Satoshi*; Baba, Masaaki*; Yamauchi, Jun*; Ikuma, Naohiko*; Uchida, Yoshiaki*; Tamura, Rui*; Iima, Yoshio*

no journal, , 

Recently, the chiral paramagnetic liquid crystals (LCs) were synthesized, whose spin sources are fixed in their rigid core. Their responses to an electric and magnetic fields are attractive topics. In general, LC molecules align with the rubbing direction on the oriented film of the LC cell. By far, by use of this surface stabilization effect on LC cell surface, we have developed this potential method of the EPR measurement with rotating the oriented LC cell sample. More recently, the chiral paramagnetic LC showing ferroelectricity was synthesized. We will report the EPR investigation of the orientation change of the ferroelectric LC in response to the switching of an applied electric field. It was shown by the EPR measurement that with no electric field, the LC molecules directed nearly uniformly along the rubbing direction on the cell surface, on the other hand, with electric field (24V), the LC molecules largely tilted from the normal line of the smectic layer.

Oral presentation

Study of meso-scale structure by polarized neutron and dynamic nuclear polarization methods

Kumada, Takayuki; Noda, Yohei; Hashimoto, Takeji; Koizumi, Satoshi

no journal, , 

We developed dynamic nuclear polarization (DNP) system for polarized small angle neutron scattering system in JAEA (SANS-J-II). The DNP system is composed of milliwave oscillator (94 GHz), cryostat (1 K), and superconducting magnet (3.5 Tesla). We succeeded in polarizing proton spins in polyetylene sample up to 63%, which exceeds the value reported elesewhere of 30$$sim$$40%.

Oral presentation

Contrast variation small-angle neutron scattering by dynamic nuclear polarization method; Investigation on crystalline structure of polyethylene

Noda, Yohei; Kumada, Takayuki; Koizumi, Satoshi; Hashimoto, Takeji

no journal, , 

We polarized nuclear spins in hydrogen atoms of polyethylene samples doped with organic radical (TEMPO) by use of dynamic nuclear polarization (DNP), in which the sample was irradiated by millimeter wave (94 GHz) at 3.3 Tesla and 1.4 K. For the samples under the DNP state, we conducted small-angle scattering experiment with polarized neutrons. For low crystalline sample (polarization: 43%), the shift of the incoherent scattering level was observed. For highly crystalline sample (polarization: 26%), the enhancement of the coherent scattering due to the crystalline structure was observed.

Oral presentation

Study of structure of crystalline polymers using dynamic nuclear polarization and small-angle neutron scattering

Kumada, Takayuki; Noda, Yohei; Hashimoto, Takeji; Koizumi, Satoshi

no journal, , 

We employed the technique of dynamic nuclear-spin polarization for small-angle neutron scattering experiment. We succeeded in observing effect of nuclear-spin polarization on coherent and incoherent scattering of cold neutrons.

Oral presentation

Investigation on structure of crystalline polyethylene by use of contrast variation small-angle neutron scattering by dynamic nuclear polarization method

Noda, Yohei; Kumada, Takayuki; Koizumi, Satoshi; Hashimoto, Takeji

no journal, , 

We polarized hydrogen nuclear spins of crystalline polyethylene samples, doped with organic radical (TEMPO), by use of dynamic nuclear polarization (DNP), in which the sample was irradiated by millimeter wave (94 GHz) at 3.3 Tesla and 1.4 K. For the samples under the DNP state, we conducted small-angle scattering experiment with polarized neutrons. For the sample with low crystallinity (polarization: 43%), the shift of the incoherent scattering level was observed. For the sample with high crystallinity (polarization: 26%), the enhancement of the coherent scattering due to the crystalline structure was observed.

77 (Records 1-20 displayed on this page)