Composite with a glassy nonporous coordination polymer enhances gas adsorption selectivity

Zheng, X.*; Kato, Masaru*; Uemura, Yohei*; Matsumura, Daiju; Yagi, Ichizo*; Takahashi, Kiyonori*; Noro, Shinichiro*; Nakamura, Takayoshi*

Inorganic Chemistry, 62(3), p.1257 - 1263, 2023/01

https://doi.org/10.1021/acs.inorgchem.2c04068

Electrochemically driven specific alkaline metal cation adsorption on a graphene interface

Yasuda, Satoshi; Tamura, Kazuhisa; Kato, Masaru*; Asaoka, Hidehito; Yagi, Ichizo*

Journal of Physical Chemistry C, 125(40), p.22154 - 22162, 2021/10

https://doi.org/10.1021/acs.jpcc.1c03322

Understanding electrochemical behavior of the alkaline metal cation-graphene interface in electrolyte is essential for understanding the fundamental electrochemical interface and development of graphene-based technologies. We report comprehensive analysis of the electrochemical behavior of both alkaline metal cations and graphene using electrochemical surface X-ray diffraction (EC-SXRD) and Raman (EC-Raman) spectroscopic techniques in which the interfacial structure of cations and the charging state and mechanical strain of the graphene can be elucidated. EC-SXRD and cyclic voltammetry demonstrated electrochemically driven specific adsorption and desorption of cations on the graphene surface involved in the dehydration and hydration process. This study provides new insight for understanding fundamental electrochemical behavior of the alkaline metal cation-graphene interface and contributes to the development of carbon-based novel applications.

Electronic effects of nitrogen atoms of supports on Pt-Ni rhombic dodecahedral nanoframes for oxygen reduction

Kato, Masaru*; Nakahoshiba, Ryota*; Ogura, Kazuya*; Tokuda, Shoichi*; Yasuda, Satoshi; Higashi, Kotaro*; Uruga, Tomoya*; Uemura, Yohei*; Yagi, Ichizo*

ACS Applied Energy Materials (Internet), 3(7), p.6768 - 6774, 2020/07

https://doi.org/10.1021/acsaem.0c00903

To understand electronic effects of nitrogen-doped and polymer-coated carbon supports on the catalytic activity of Pt-based nanostructured catalysts, we prepared PtNi nanoframes (NFs) supported on polybenzimidazole (PBI)-coated and uncoated carbon nanotubes for the oxygen reduction reaction (ORR), and then compared their catalytic activities and electronic properties with those of NFs immobilized on nitrogen-doped and undoped carbon supports. Although both PBI-coating and nitrogen-doping approaches improved the catalytic activity of NFs, X-ray photoelectron spectroscopy and X-ray absorption spectroscopy revealed that nitrogen doping showed electronic effects on NFs, whereas PBI-coating showed almost no impact on the electronic state of NFs but stabilized Pt(OH) species under electrochemical conditions. Our studies demonstrate that difference in microscopic environments of nitrogen atoms at the catalyst/support interface is highly sensitive to the electronic effects of supports on Pt-based electrocatalysts.

Incorporation of multinuclear copper active sites into nitrogen-doped graphene for electrochemical oxygen reduction

Kato, Masaru*; Muto, Marika*; Matsubara, Naohiro*; Uemura, Yohei*; Wakisaka, Yuki*; Yoneuchi, Tsubasa*; Matsumura, Daiju; Ishibara, Tomoko*; Tokushima, Takashi*; Noro, Shinichiro*; et al.

ACS Applied Energy Materials (Internet), 1(5), p.2358 - 2364, 2018/05

https://doi.org/10.1021/acsaem.8b00491

Annual report of Nuclear Emergency Assistance and Training Center (April 1, 2013 - March 31, 2014)

Sato, Takeshi; Muto, Shigeo; Akiyama, Kiyomitsu; Aoki, Kazufumi; Okamoto, Akiko; Kawakami, Takeshi; Kume, Nobuhide; Nakanishi, Chika; Koie, Masahiro; Kawamata, Hiroyuki; et al.

JAEA-Review 2014-048, 69 Pages, 2015/02

JAEA-Review-2014-048.pdf:13.91MB

JAEA was assigned as a designated public institution under the Disaster Countermeasures Basic Act and under the Armed Attack Situations Response Act. Based on these Acts, the JAEA has the responsibility of providing technical support to the national government and/or local governments in case of disaster responses or response in the event of a military attack, etc. In order to fulfill the tasks, the JAEA has established the Emergency Action Plan and the Civil Protection Action Plan. In case of a nuclear emergency, NEAT dispatches specialists of JAEA, supplies the national government and local governments with emergency equipment and materials, and gives technical advice and information. In normal time, NEAT provides various exercises and training courses concerning nuclear disaster prevention to those personnel taking an active part in emergency response institutions of the national and local governments, police, fire fighters, self-defense forces, etc. in addition to the JAEA itself. The NEAT also researches nuclear disaster preparedness and response, and cooperates with international organizations. In the FY2013, the NEAT accomplished the following tasks: (1) Technical support activities as a designated public institution in cooperation with the national and local governments, etc. (2) Human resource development, exercise and training of nuclear emergency response personnel for the national and local governments, etc. (3) Researches on nuclear disaster preparedness and response, and sending useful information (4) International contributions to Asian countries on nuclear disaster preparedness and response in collaboration with the international organizations

Conceptual design of multipurpose compact research reactor; Annual report FY2011

Watahiki, Shunsuke; Hanakawa, Hiroki; Imaizumi, Tomomi; Nagata, Hiroshi; Ide, Hiroshi; Komukai, Bunsaku; Kimura, Nobuaki; Miyauchi, Masaru; Ito, Masayasu; Nishikata, Kaori; et al.

JAEA-Technology 2013-021, 43 Pages, 2013/07

JAEA-Technology-2013-021.pdf:5.12MB

The number of research reactors in the world is decreasing because of their aging. On the other hand, the necessity of research reactor, which is used for human resources development, progress of the science and technology, industrial use and safety research is increasing for the countries which are planning to introduce the nuclear power plants. From above background, the Neutron Irradiation and Testing Reactor Center began to discuss a basic concept of Multipurpose Compact Research Reactor (MCRR) for education and training, etc., on 2010 to 2012. This activity is also expected to contribute to design tool improvement and human resource development in the center. In 2011, design study of reactor core, irradiation facilities with high versatility and practicality, and hot laboratory equipment for the production of Mo-99 was carried out. As the result of design study of reactor core, subcriticality and operation time of the reactor in consideration of an irradiation capsule, and about the transient response of the reactor to the reactivity disturbance during automatic control operation, it was possible to do automatic operation of MCRR, was confirmed. As the result of design study of irradiation facilities, it was confirmed that the implementation of an efficient mass production radioisotope Mo-99 can be expected. As the result of design study with hot laboratory facilities, Mo-99 production, RI export devised considered cell and facilities for exporting the specimens quickly was designed.

Conceptual design of multipurpose compact research reactor; Annual report FY2010 (Joint research)

Imaizumi, Tomomi; Miyauchi, Masaru; Ito, Masayasu; Watahiki, Shunsuke; Nagata, Hiroshi; Hanakawa, Hiroki; Naka, Michihiro; Kawamata, Kazuo; Yamaura, Takayuki; Ide, Hiroshi; et al.

JAEA-Technology 2011-031, 123 Pages, 2012/01

JAEA-Technology-2011-031.pdf:16.08MB

The number of research reactors in the world is decreasing because of their aging. However, the planning to introduce the nuclear power plants is increasing in Asian countries. In these Asian countries, the key issue is the human resource development for operation and management of nuclear power plants after constructed them, and also the necessity of research reactor, which is used for lifetime extension of LWRs, progress of the science and technology, expansion of industry use, human resources training and so on, is increasing. From above backgrounds, the Neutron Irradiation and Testing Reactor Center began to discuss basic concept of a multipurpose low-power research reactor for education and training, etc. This design study is expected to contribute not only to design tool improvement and human resources development in the Neutron Irradiation and Testing Reactor Center but also to maintain and upgrade the technology on research reactors in nuclear power-related companies. This report treats the activities of the working group from July 2010 to June 2011 on the multipurpose low-power research reactor in the Neutron Irradiation and Testing Reactor Center and nuclear power-related companies.

Electron-beam-induced color imaging of acid-chromic polymer films

Maekawa, Yasunari; Yuasa, Kanako*; Enomoto, Kazuyuki; Matsushita, Harumi*; Kato, Jun*; Yamashita, Takashi*; Ito, Kazuo*; Yoshida, Masaru

Chemistry of Materials, 20(16), p.5320 - 5324, 2008/08

https://doi.org/10.1021/cm800650q

Polymer films with acid-responsive chromic dyes and acid generators have been designed for an electron beam (EB)-induced color imaging system. Arylsulfonic acid esters and triphenylsulfonium salts were used as an EB-sensitive acid generator; the acid (H) allows a chromic reaction with rhodamine B base (RB) and 4,4'-bis(dimethylamino)benzhydrol (BH) to be triggered. Upon EB irradiation, poly(methyl methacrylate) (PMMA) films consisting of RB or BH and acid generators exhibited a characteristic absorption band with max at 560 and at 612 nm, respectively, and an isosbestic point. These spectral changes clearly indicate that colorless chromic dyes in PMMA are transformed selectively to the colored form. The color imaging of these films was performed by electron beam direct writing (EBDW) with a 50 nm diameter beam to form 100 - 1000 nm line and space patterns and was evaluated by optical and confocal laser microscopy. EBDW on the acid chromic polymer films, especially for BH, yielded clear color imaging of 100 - 200 nm line and space patterns with a dose of only 10 C/cm. The confocal laser microscopy gave thinner lines than the laser wavelength (632.8 nm), probably because of the large change in refractive index of the patterned film induced by EB irradiation even with a low energy dose.

Superconducting MgB thin film detector for neutrons

Ishida, Takekazu*; Nishikawa, Masatoshi*; Fujita, Yoshifumi*; Okayasu, Satoru; Katagiri, Masaki*; Sato, Kazuo*; Yotsuya, Tsutomu*; Shimakage, Hisashi*; Miki, Shigehito*; Wang, Z.*; et al.

Journal of Low Temperature Physics, 151(3-4), p.1074 - 1079, 2008/05

https://doi.org/10.1007/s10909-008-9790-x

The superconducting neutron detector using high-quality B-enriched MgB thin films at higher operating temperatures has been proposed, where a resistance change induced by the nuclear reaction of neutron and B in MgB is used to detect a neutron. Cold neutrons from a nuclear research reactor irradiated the MgB detector, and the output voltage was clearly observed through a low-noise amplifier by using a digital oscilloscope. The out-of-equilibrium thermodynamics was investigated by means of the time-dependent Ginzburg-Landau equations by using the Earth Simulator.

Novel anisotropic superconductivity in nano-structured superconductors

Kato, Masaru*; Koyama, Tomio*; Machida, Masahiko; Hayashi, Masahiko*; Ebisawa, Hiromichi*; Ishida, Takekazu*

Physica B; Condensed Matter, 403(5-9), p.996 - 998, 2008/04

https://doi.org/10.1016/j.physb.2007.10.275

Using the Bogoliubov-de Gennes equation of a tight-binding electron model with attractive on-site and nearest-neighbor sites interactions, we investigate the superconducting structure of nano-structured anisotropic superconductors. Numerical results show that nano-scaled /4-rotated square d-wave superconductors show various type of uperconductivities depending on the size. Especially, + superconductivity, appears when size of superconductors is 10 times of coherence length.