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Journal Articles

Uranium chelating ability of decorporation agents in serum evaluated by X-ray absorption spectroscopy

Uehara, Akihiro*; Matsumura, Daiju; Tsuji, Takuya; Yakumaru, Haruko*; Tanaka, Izumi*; Shiro, Ayumi*; Saito, Hiroyuki*; Ishihara, Hiroshi*; Homma-Takeda, Shino*

Analytical Methods, 14(24), p.2439 - 2445, 2022/06

 Times Cited Count:3 Percentile:60.41(Chemistry, Analytical)

Journal Articles

Mesospheric ionization during substorm growth phase

Murase, Kiyoka*; Kataoka, Ryuho*; Nishiyama, Takanori*; Nishimura, Koji*; Hashimoto, Taishi*; Tanaka, Yoshimasa*; Kadokura, Akira*; Tomikawa, Yoshihiro*; Tsutsumi, Masaki*; Ogawa, Yasunobu*; et al.

Journal of Space Weather and Space Climate (Internet), 12, p.18_1 - 18_16, 2022/06

 Times Cited Count:1 Percentile:22.72(Astronomy & Astrophysics)

We identified two energetic electron precipitation (EEP) events during the growth phase of moderate substorms and estimated the mesospheric ionization rate for an EEP event for which the most comprehensive dataset from ground-based and space-born instruments was available. The mesospheric ionization signature reached below 70 km altitude and continued for ~15 min until the substorm onset, as observed by the PANSY radar and imaging riometer at Syowa Station in the Antarctic region. We also used energetic electron flux observed by the Arase and POES 15 satellites as the input for the air-shower simulation code PHITS to quantitatively estimate the mesospheric ionization rate. Combining the cutting-edge observations and simulations, we shed new light on the space weather impact of the EEP events during geomagnetically quiet times, which is important to understand the possible link between the space environment and climate.

Journal Articles

Fundamental study for decorporation of plutonium by chelating agents; Coordination analyses of simulated plutonium with chelating agents by X-ray absorption spectroscopy

Uehara, Akihiro*; Shuhui, X.*; Sato, Ryotaro*; Matsumura, Daiju; Tsuji, Takuya; Yakumaru, Haruko*; Shiro, Ayumi*; Saito, Hiroyuki*; Tanaka, Izumi*; Ishihara, Hiroshi*; et al.

Advances in X-Ray Chemical Analysis, Japan, 53, p.223 - 229, 2022/03

no abstracts in English

Journal Articles

Transient ionization of the mesosphere during auroral breakup; Arase satellite and ground-based conjugate observations at Syowa Station

Kataoka, Ryuho*; Nishiyama, Takanori*; Tanaka, Yoshimasa*; Kadokura, Akira*; Uchida, Herbert Akihito*; Ebihara, Yusuke*; Ejiri, Mitsumu*; Tomikawa, Yoshihiro*; Tsutsumi, Masaki*; Sato, Kaoru*; et al.

Earth, Planets and Space (Internet), 71(1), p.9_1 - 9_10, 2019/12

 Times Cited Count:8 Percentile:40.25(Geosciences, Multidisciplinary)

Transient ionization of the mesosphere was detected at around 65 km altitude during the isolated auroral expansion occurred at 2221-2226 UT on June 30, 2017. A general-purpose Monte Carlo particle transport code PHITS suggested that significant ionization is possible in the middle atmosphere due to auroral X-rays from the auroral electrons of $$<$$10 keV.

Journal Articles

Imidazolium-based anion exchange membranes for alkaline anion fuel cells; Elucidation of the morphology and the interplay between the morphology and properties

Zhao, Y.; Yoshimura, Kimio; Shishitani, Hideyuki*; Yamaguchi, Susumu*; Tanaka, Hirohisa*; Koizumi, Satoshi*; Szekely, N.*; Radulescu, A.*; Richter, D.*; Maekawa, Yasunari

Soft Matter, 12(5), p.1567 - 1578, 2016/02

 Times Cited Count:27 Percentile:79.79(Chemistry, Physical)

Journal Articles

Nitrogen $$K$$-edge soft X-ray natural circular dichroism of histidine thin film

Izumi, Yudai; Tanaka, Masahito*; Tanigawa, Yoshiaki*; Tanabe, Maiko*; Momoki, Yohei*; Iwai, Miki*; Takenaka, Shun*; Ishiyama, Kimihiro*; Kuroki, Misa*; Muro, Takayuki*; et al.

Journal of Physics; Conference Series, 502(1), p.012038_1 - 012038_4, 2014/04

 Times Cited Count:2 Percentile:72.7(Materials Science, Multidisciplinary)

Journal Articles

Study of feasible and sustainable multilateral approach on nuclear fuel cycle

Kuno, Yusuke; Tazaki, Makiko; Akiba, Mitsunori*; Adachi, Takeo*; Takashima, Ryuta*; Izumi, Yoshinori*; Tanaka, Satoru*

Proceedings of International Nuclear Fuel Cycle Conference; Nuclear Energy at a Crossroads (GLOBAL 2013) (CD-ROM), p.965 - 974, 2013/09

Multilateral Nuclear Approach (MNA) provides services on the frontend and the backend to the states possessing nuclear power plants with nuclear non-proliferation measures and without interfering with the inalienable right in NPT may be one of the most effective and efficient manners for peaceful use of nuclear energy. Recent MNA discussions tend to focus on reliable fuel supply, namely front-end of NFC, where proliferation of uranium enrichment can be deterred. At the same time, the MNA capability to provide assurance/service that the Spent Fuel be managed properly is actually more important. In this work a regional MNA framework was studied to fulfil the above mentioned points.

Journal Articles

Characteristic oxygen $$K$$-edge circular dichroism spectra of amino acid films by improved measurement technique

Izumi, Yudai*; Tanabe, Maiko*; Imazu, Akiko*; Mimoto, Aki*; Tanaka, Masahito*; Agui, Akane; Muro, Takayuki*; Nakagawa, Kazumichi*

Journal of Chemical Physics, 138(7), p.074305_1 - 074305_10, 2013/02

 Times Cited Count:9 Percentile:32.23(Chemistry, Physical)

no abstracts in English

JAEA Reports

Design, fabrication and transportation of Si rotating device

Kimura, Nobuaki; Imaizumi, Tomomi; Takemoto, Noriyuki; Tanimoto, Masataka; Saito, Takashi; Hori, Naohiko; Tsuchiya, Kunihiko; Romanova, N. K.*; Gizatulin, S.*; Martyushov, A.*; et al.

JAEA-Technology 2012-012, 34 Pages, 2012/06

JAEA-Technology-2012-012.pdf:12.91MB

Si semiconductor production by Neutron Transmutation Doping (NTD) method using the Japan Materials Testing Reactor (JMTR) has been investigated in Neutron Irradiation and Testing Reactor Center, Japan Atomic Energy Agency (JAEA) in order to expand industry use. As a part of investigations, irradiation test of silicon ingot for development of NTD-Si with high quality was planned using WWR-K in Institute of Nuclear Physics (INP), National Nuclear Center of Republic of Kazakhstan (NNC-RK) based on one of specific topics of cooperation (STC), Irradiation Technology for NTD-Si (STC No.II-4), on the implementing arrangement between NNC-RK and the JAEA for "Nuclear Technology on Testing/Research Reactors" in cooperation in research and development in nuclear energy and technology. As for the irradiation test, Si rotating device was fabricated in JAEA, and the fabricated device was transported with irradiation specimens from JAEA to INP-NNC-RK. This report described the design, the fabrication, the performance test of the Si rotating device and transportation procedures.

Journal Articles

Theoretical modelling of hierarchically associated structures in hydrophobically modified PNIPAM aqueous solutions on the basis of a neutron scattering study

Koga, Tsuyoshi*; Tanaka, Fumihiko*; Motokawa, Ryuhei; Koizumi, Satoshi*; Winnik, F. M.*

Macromolecular Symposia, 291-292(1), p.177 - 185, 2010/05

 Times Cited Count:4 Percentile:60.52(Polymer Science)

Journal Articles

Radiation-induced chemical evolution of biomolecules

Nakagawa, Kazumichi*; Matsui, Takahiro*; Izumi, Yudai*; Agui, Akane; Tanaka, Masahito*; Muro, Takayuki*

Radiation Physics and Chemistry, 78(12), p.1198 - 1201, 2009/12

 Times Cited Count:4 Percentile:30.49(Chemistry, Physical)

Chemical-evolution in glycilglycine (Gly2) films irradiated by 146 nm light was studied. It was found that quantum efficiency of chemical evolution from Gly2 to glycilglycilglycine (Gly3) is smaller than that to glycilglycilglycilglycine (Gly4) due to the multiple step of reaction. From natural circular dichroism spectra measurements for serine and alanine films, we found the splitting of 1s$$rightarrow$$$$pi$$$$^{*}$$ transitions in the energy region of oxygen 1s.

Journal Articles

Measurement and comparison of absolute value of soft X-ray natural circular dichroism of serine and alanine

Izumi, Yudai*; Imazu, Akiko*; Mimoto, Aki*; Tanaka, Masafumi*; Nakagawa, Kazumichi*; Tanaka, Masahito*; Agui, Akane; Muro, Takayuki*

Journal of Physics; Conference Series, 190, p.012209_1 - 012209_4, 2009/11

 Times Cited Count:8 Percentile:87.26(Physics, Condensed Matter)

Soft X-ray natural circular dichroism spectra of serine and alaninethin films, were measured in absolute value with the focus at the oxygen 1s to $$pi$$$$^{*}$$ transition of COO$$^{-}$$. The soft X-ray natural circular dichroism spectra intensity of L-Ala was about ten times as large as that of L-Ser. Those differences would reflect the chiral environment of the core hole oxygen atoms of COO$$^{-}$$.

Journal Articles

Combined SANS, SEC, NMR, and UV-Vis studies of simultaneous living anionic copolymerization process; Simultaneous elucidation of propagating living chains at three different length scales

Zhao, Y.; Tanaka, Hirokazu*; Miyamoto, Nobuyoshi*; Koizumi, Satoshi; Hashimoto, Takeji

Macromolecules, 42(5), p.1739 - 1748, 2009/04

 Times Cited Count:15 Percentile:45.74(Polymer Science)

Journal Articles

Theoretical modeling of associated structures in aqueous solutions of hydrophobically modified telechelic PNIPAM based on a neutron scattering study

Koga, Tsuyoshi*; Tanaka, Fumihiko*; Motokawa, Ryuhei; Koizumi, Satoshi; Winnik, F. M.*

Macromolecules, 41(23), p.9413 - 9422, 2008/11

 Times Cited Count:73 Percentile:89.36(Polymer Science)

On the basis of results from a small-angle neutron scattering (SANS) study of aqueous solutions of a telechelic PNIPAM with octadecyl end groups, we developed a theoretical model of the self-assembly of this polymer in water as a function of temperature and concentration. This model leads us to the following description. In solutions of concentration 10 gL$$^{-1}$$ kept between 10 and 20$$^{circ}$$C, telechelic PNIPAMs (${it M}$$ $_{n}$$) 22 200 gmol$$^{-1}$$) associate in the form of flower micelles, containing about 12 polymer chains, assembled in a three-layered core-shell morphology with an inner core consisting of the octadecyl units, a dense inner shell consisting of partly collapsed PNIPAM chains, and an outer shell of swollen hydrated chains. Drastic changes in the scattering profile of the solution heated above 31$$^{circ}$$C are attributed to the formation of mesoglobules (diameter of 40 nm) consisting of about 1000 polymer chains. On further heating, the aggregation number of the mesoglobules increases. It reaches a value of 9000 at 34$$^{circ}$$C and stays constant upon further heating. In solutions of lower concentration (1 gL$$^{-1}$$), association of flower micelles and mesoglobules does not occur; however, the structure of individual flower micelles and mesoglobules is not affected by the change in concentration. In solutions of 50 gL$$^{-1}$$ in which flower micelles are expected to be partially connected by bridge chains, a peak attributed to correlation between flower micelles appears in the scattering profiles recorded at low temperature (10-20$$^{circ}$$C). In spite of the intermicellar bridging connection, the overall temperature dependence of the scattering profile at 50 gL$$^{-1}$$ remains similar to that at 10 gL$$^{-1}$$. Distinct features of the self-assembled structures formed in aqueous telechelic PNIPAM solutions are discussed in terms of the interactions between water and the polymer main chains.

Journal Articles

Control of self-assembling processes of polyamidoamine dendrimers and Pd nanoparticles

Tanaka, Hirokazu*; Hashimoto, Takeji; Koizumi, Satoshi; Ito, Hideaki*; Naka, Kensuke*; Chujo, Yoshiki*

Macromolecules, 41(5), p.1815 - 1824, 2008/03

 Times Cited Count:8 Percentile:26.86(Polymer Science)

We have investigated the self-assembly formed by palladium acetate (Pd(OAc)$$_{2}$$) and polyamidoamine dendrimers (GN-NH$$_{2}$$) in a mixed solvent of methanol and N, N-dimethylformamide. We aim to explore effects of the generation number (GN) and concentration of the dendrimers, [GN-NH$$_{2}$$], on the self-assembly of the dendrimers (defined hereafter as "templates") and the Pd nanoparticles inside the templates in order to clarify physical factors controlling the self-assembling mechanisms. We found that the templates are formed only when [GN-NH$$_{2}$$] falls below a critical value and thereby a sufficient amount of Pd(OAc)$$_{2}$$ exists as the binders between the dendrimers. Otherwise dendrimers are molecularly dispersed in solution.

Journal Articles

Self-assembly of synthetic cellulose during in-vitro enzymatic polymerization process as studied by a combined small-angle scattering method

Tanaka, Hirokazu*; Koizumi, Satoshi; Hashimoto, Takeji; Kurosaki, Kazuhiro*; Kobayashi, Shiro*

Macromolecules, 40(17), p.6304 - 6315, 2007/08

 Times Cited Count:30 Percentile:65.02(Polymer Science)

We have investigated the self-assembling process of cellulose artificially synthesized via enzymatic polymerization as one of general problems of non-equilibrium phenomenon and pattern formation. The chemical reaction and the self-assembling process were explored at real time and in-situ by a combined small-angle neutron scattering (SANS), small-angle X-ray scattering (SAXS), ultra-SANS and ultra-SAXS method, together with wide-angle X-ray diffraction and field-emission scanning electron microscopy. The results revealed for the first time the following pieces of new evidence: (1) The enzymes (cellulase) as a catalyst aggregate themselves into associations; (2) Cellulose molecules created at each active site of enzymes associate themselves around the enzyme associations into cellulose aggregates having surface fractal dimensions Ds, increasing from 2 to 2.3 with reaction time. (3) The fractal structure formed at the end of the reaction extends over a surprisingly wide length scale ranging from 30 nm to 30 $$mu$$m (3 orders of magnitude).

Journal Articles

Combined in situ and time-resolved SANS and SAXS studies of chemical reactions at specific sites and self-assembling processes of reaction products; Reduction of palladium ions in self-assembled polyamidoamine dendrimers as a template

Tanaka, Hirokazu*; Koizumi, Satoshi; Hashimoto, Takeji; Ito, Hideaki*; Sato, Masahide*; Naka, Kensuke*; Chujo, Yoshiki*

Macromolecules, 40(12), p.4327 - 4337, 2007/06

 Times Cited Count:32 Percentile:67.9(Polymer Science)

We reported the reduction process of palladium(II) acetate, Pd(OAc)$$_{2}$$, and self-assembling process of the resulting palladium atoms, Pd(0)'s, into nanoparticles in the presence of the first-generation polyamidoamine dendrimer (G1-NH$$_{2}$$) in non-aqueous solution. The process was induced by mixing the following two solutions: (A) Pd(OAc)$$_{2}$$ dissolved in N,N-dimethylformamide (DMF) and (B) the G1-NH$$_{2}$$ dissolved in methanol, under a specific condition of $$r$$ $$equiv$$ [Pd(OAc)$$_{2}$$]/[-NH$$_{2}$$] = 3.3 where [-NH$$_{2}$$] is mole concentration of the amine groups in the dendrimer in the reaction solution. The reaction and reaction-induced self-assembling process were explored in-situ by means of a combined time-resolved method of small-angle neutron scattering and small-angle X-ray scattering. The method revealed time-evolution of a series of self-assembling processes occurring in the system.

Journal Articles

A Combined small-angle scattering study of a chemical reaction at specific sites and reaction-induced self-assembly as a problem in open non-equilibrium phenomena

Hashimoto, Takeji; Tanaka, Hirokazu*; Koizumi, Satoshi; Naka, Kensuke*; Chujo, Yoshiki*

Journal of Applied Crystallography, 40(s1), p.s73 - s77, 2007/04

 Times Cited Count:18 Percentile:83.38(Chemistry, Multidisciplinary)

As a problem in open non-equilibrium phenomena, we present small-angle scattering studies of chemical-reaction at specific sites and reaction-induced self-assembly of the system which is induced by mixing two stable solutions of palladium (II) acetate (Pd(OAc)$$_{2}$$) in N,N-dimethylformamide and the second-generation polyamidoamine dendrimer in methanol.

Journal Articles

Wide-$$q$$ observation from 10$$^{-4}$$ to 2.0$AA $^{-1}$$ using a focusing and polarized neutron small-angle scattering spectrometer, SANS-J-II

Iwase, Hiroki; Koizumi, Satoshi; Suzuki, Junichi; Oku, Takayuki; Sasao, Hajime*; Tanaka, Hirokazu*; Shimizu, Hirohiko*; Hashimoto, Takeji

Journal of Applied Crystallography, 40(s1), p.s414 - s417, 2007/04

 Times Cited Count:15 Percentile:80.33(Chemistry, Multidisciplinary)

In order to extend an upper q-limit larger, high-angle He sub-detectors were installed on focusing and polarized neutron small-angle scattering spectrometer (SANS-J-II) at JRR-3, Tokai. Consequently, its upper q-limit was improved from 0.2$AA $^{-1}$$ to 2$AA $^{-1}$$. To quantitatively discriminate spin incoherent scattering from hydrogen or to perform nuclear spin polarization contrast variation, a remanent supermirror analyser is also available on the high-angle sub detector. By combining a focusing ultra-small angle scattering, realized by compound and/or magnetic lens and high resolution area detector, SANS-J-II is able to cover from 3$$times$$10$$^{-3}$$ $AA $^{-1}$$ to 2$AA $^{-1}$$ (four order of magnitude of q), which profits to investigate hierarchically ordered system, found widely in hard, soft and bio-materials.

Journal Articles

Introduction to plasma fusion energy

Takamura, Shuichi*; Kado, Shinichiro*; Fujii, Takashi*; Fujiyama, Hiroshi*; Takabe, Hideaki*; Adachi, Kazuo*; Morimiya, Osamu*; Fujimori, Naoji*; Watanabe, Takayuki*; Hayashi, Yasuaki*; et al.

Kara Zukai, Purazuma Enerugi No Subete, P. 164, 2007/03

no abstracts in English

64 (Records 1-20 displayed on this page)