Magnetic orderings from spin-orbit coupled electrons on kagome lattice

Watanabe, Jin*; Araki, Yasufumi; Kobayashi, Koji*; Ozawa, Akihiro*; Nomura, Kentaro*

Journal of the Physical Society of Japan, 91(8), p.083702_1 - 083702_5, 2022/08

https://doi.org/10.7566/JPSJ.91.083702

We investigate magnetic orderings on kagome lattice numerically from the tight-binding Hamiltonian of electrons, governed by the filling factor and spin-orbit coupling (SOC) of electrons. We find that even a simple kagome lattice model can host both ferromagnetic and noncollinear antiferromagnetic orderings depending on the electron filling, reflecting gap structures in the Dirac and flat bands characteristic to the kagome lattice. Kane-Mele- or Rashba-type SOC tends to stabilize noncollinear orderings, such a magnetic spirals and 120-degree antiferromagnetic orderings, due to the effective Dzyaloshinskii-Moriya interaction from SOC. The obtained phase structure helps qualitative understanding of magnetic orderings in various kagome-layered materials with Weyl or Dirac electrons.

Development of evaluation method for photocatalytic ability by ion chromatography combined with a flow-type reactor; Application to immobilized photocatalyst materials prepared by double-layer coating method

Sugita, Tsuyoshi; Kobayashi, Kentaro*; Yamazaki, Taiki*; Isaka, Mayu*; Itabashi, Hideyuki*; Mori, Masanobu*

Journal of Photochemistry and Photobiology A; Chemistry, 400, p.112662_1 - 112662_8, 2020/09

https://doi.org/10.1016/j.jphotochem.2020.112662

In this study, we developed an in-line photocatalytic performance evaluation system in which a flow reactor was connected to the ion chromatography to accurately evaluate the performance of the photocatalyst. This system was used to evaluate the photocatalyst supported by the two-layer support method on the substrate, such as glass beads. The performance of the photocatalyst was evaluated using dimethyl sulfoxide (DMSO), and it was possible to monitor the decomposition of DMSO by UV and the formation of by-products, such as methane sulfonate (MSO) and sulfate (SA). This system can be expected to be useful not only for evaluating the decomposition performance of an object using a photocatalyst but also for evaluating the byproducts.

Enhanced aqueous adsorption and photodecomposition of anionic organic target by amino group-modified TiO as anionic adsorptive photocatalyst

Sugita, Tsuyoshi; Kobayashi, Kenichi*; Kobayashi, Kentaro*; Yamazaki, Taiki*; Fujii, Kengo*; Itabashi, Hideyuki*; Mori, Masanobu*

Journal of Photochemistry and Photobiology A; Chemistry, 356, p.71 - 80, 2018/04

https://doi.org/10.1016/j.jphotochem.2017.12.025

Photocatalysts shows high redox property only by light irradiation. However, the reaction performance is lowered in aqueous phase due to the low contact efficiency between catalyst and targets. In this study, to enhance aqueous adsorption and photodecomposition of anionic organic target, we developed an amino functional-based spacer (3-[2-(2- aminoethylamino)ethylamino]propyl-trimethoxysilane, DETA), and used it to modify TiO. The modified catalyst with positively charged amino groups could enhance the adsorption and photodecomposition of anionic organic targets.

Real-time observation of irradiated HeLa-cell modified by fluorescent ubiquitination-based cell-cycle indicator using synchrotron X-ray microbeam

Narita, Ayumi; Kaminaga, Kiichi; Yokoya, Akinari; Noguchi, Miho; Kobayashi, Katsumi*; Usami, Noriko*; Fujii, Kentaro

Radiation Protection Dosimetry, 166(1-4), p.192 - 196, 2015/09

https://doi.org/10.1093/rpd/ncv156

For the knowledge about irradiation effects of mammalian cells depending on the cell cycle, most of them had been analyzed by statistical approches. Our purpose is to establish the method for real-time observation of irradiated cells under a microscope. Fluorescent ubiquitination-based cell cycle indicator (FUCCI) human cancer (HeLa) cells (red indicates G1; green, S/G2) were exposed to a synchrotron X-ray microbeam. Cells in either G1 or S/G2 were selectively irradiated according to cell color observed in the same microscopic field in a culture dish. Time-lapse micrographs of the irradiated cells were acquired for 24 h after irradiation. The cell cycle was strongly arrested by irradiation at S/G2 and never progressed to G1. In contrast, cells irradiated at G1 progress to S/G2 with a similar time course as non-irradiated control cells. These results show single FUCCI cell exposure and live cell imaging are powerful methods for studying radiation effects on the cell cycle.

Development of an alternative plutonium canister assay system (APCA) using He-3 alternative neutron detector

Ozu, Akira; Kureta, Masatoshi; Haruyama, Mitsuo; Takase, Misao; Kurata, Noritaka; Kobayashi, Nozomi; Soyama, Kazuhiko; Nakamura, Tatsuya; Sakasai, Kaoru; To, Kentaro; et al.

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-34-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2013/10

no abstracts in English

Recent progress in the energy recovery linac project in Japan

Sakanaka, Shogo*; Akemoto, Mitsuo*; Aoto, Tomohiro*; Arakawa, Dai*; Asaoka, Seiji*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2338 - 2340, 2010/05

http://accelconf.web.cern.ch/AccelConf/IPAC10/papers/tupe091.pdf

Future synchrotron light source using a 5-GeV energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting R&D efforts for that. We are developing high-brightness DC photocathode guns, two types of cryomodules for both injector and main superconducting (SC) linacs, and 1.3 GHz high CW-power RF sources. We are also constructing the Compact ERL (cERL) for demonstrating the recirculation of low-emittance, high-current beams using above-mentioned critical technologies.

Cement based encapsulation trials for low-level radioactive effluent containing nitrate salts

Sugaya, Atsushi; Horiguchi, Kenichi; Tanaka, Kenji; Kobayashi, Kentaro

Materials Research Society Symposium Proceedings, Vol.1107, p.173 - 179, 2008/00

In Nuclear Fuel Reprocessing Plant, it is necessary to dispose of a large amount of low level radioactive effluent containing nitrate as a major ingredient, safely and economically. Therefore, engineering developments concerning a cement based encapsulation process have been carried out in JAEA. From the viewpoint of disposal cost decrease, a low level radioactive effluent is passed through the nuclide separation process before cementation to concentrate the radioactivity into the minimum volume for conditioning and disposal. Two kinds of effluents are generated as a result of the nuclide separation; Non-radioactive simulants were prepared for each of these waste streams, and used in encapsulation trials to investigate a special slag cement, on a beaker scale and at full scale (200-litres). The results have confirmed that the nitrate effluent, evaporated up to a predetermined density, can be successfully encapsulated at a salt filling rate of 50wt%, to produce a wasteform which satisfies the required conditions. In the slurry effluent, the strength of the product decreased when carbonate concentration was high. However, it was confirmed that the product made at salt filling rate 50wt% satisfied the required conditions, if the carbonate concentration in the effluent was decreased to 10 g/L or less.

Development of new treatment process for low level liquid waste at Tokai reprocessing plant

Saito, Yasuo; Takano, Masato; Tanaka, Kenji; Kobayashi, Kentaro; Otani, Yoshikuni

Proceedings of International Symposium on Radiation Safety Management 2007 (ISRSM 2007), p.275 - 280, 2007/11

The Low-radioactive Waste Treatment Facility (LWTF), which aims to provide the safe, efficient and economic treatment and disposal of Low-level Liquid Waste (LLW) generated from LWR spent fuel reprocessing, was constructed at the Tokai Reprocessing Plant (TRP), and a cold test is now being carried out. New treatment processes such as a removal process for radio-nuclides and the ROBE (BORSAURE EINENGUNG ANLAGE) solidification process are being implemented in the LWTF. In order to treat the large amount of sodium nitrate contained in the concentrated LLW with higher safety and economy, R&D work on nitrate-ion decomposition technology using a catalytic reduction method and on the solidification process by cementation is being undertaken. The results of this R&D will be adopted in the LWTF in the near future. This report describes an outline of liquid waste treatment in the LWTF and new treatment technologies for LLW to achieve safe, efficient and economic treatment and disposal.

Operating Document on Management Division Waste Management Section in Tokai Works in the 2003 Fiscal Year

Kobayashi, Kentaro; Akutsu, Shigeru; Sasayama, Yasuo; Nakanishi, Masahiro; Ozone, Takashi; Tomomi, Terunuma,; Mogaki, Isao*

JNC TN8440 2005-007, 138 Pages, 2005/07

JNC-TN8440-2005-007.pdf:7.47MB

This document is announced about the task of Waste Management Section of Waste Management Division in 2003. Mainly, our tasks are fractionating, incinerating and storing low active solid waste and storing high active solid waste. In addition, we are performing required correspondence about management program of low level waste. We had treated and stored waste safely according to our plan. As a result, we have achieved following outcomes. 1. We incinerated the combustible low active solid waste that is generated by the operation of Tokai Reprocessing Plant and the recovery operation of incident at Low Active Liquid Waste Asphalt Solidification Facility. Waste of this recovery operation is stored in the 2nd Low Active Liquid Waste Asphalt Solidification Storage Facility. We incinerated 58 ton of wastes. 2. We stored low active solid waste 854 drums that accommodate 200L. According to the time of Low-Level Waste Treatment Facility completion, we will be able to avoid full of storage. 3. We stored high active solid waste of 148 drums that accommodate 200L. For the time being, there is no problem as regards the administration of storage facility. 4. We carried out the management program of low level solid waste according to plan.

Operating document on management division waste management section in Tokai works in 2002 fiscal year

Kobayashi, Kentaro; Isozaki, Koei

JNC TN8440 2003-003, 139 Pages, 2003/04

JNC-TN8440-2003-003.pdf:19.77MB

This document is announced about task of Waste Management Division Waste Management Section in the 2002 fiscal year. Mainly, our task is that treated Low level solid waste, stored Low level solid waste and stored High level solid waste. Those wastes are generated from Tokai reprocessing plant in Tokai Works. We carried out task safety as planned. The results are as follows. (1)We incinerated that combustible Low level solid waste of 70.5 ton in Incinerate facility. Such wastes were generated from operation of Tokai reprocessing plant and cleaned up operation of Tokai bituminization facility (The fire and explosion incident of Tokai bituminization facility). (2)We stored Low level solid waste that generated the waste of 1,071 drums. It is found that Storage facilities will not fill on this condition Low level radioactive waste treatment facility is started operation. (3)We stored High level solid waste that generated the waste of 117 drums from Tokai reprocessing plant. And, it is found that there facilities will not fill on this condition generated wastes of about 100 drams by a year. (4)We started printing of the data from the 2002 fiscal year to intranet which amount of stored Low level solid waste and High level solid waste in order to educate the amount reduction of waste generating (at those facilities).