Spontaneous topological Hall effect induced by non-coplanar antiferromagnetic order in intercalated van der Waals materials

Takagi, Hirotaka*; Takagi, Rina*; Minami, Susumu*; Nomoto, Takuya*; Oishi, Kazuki*; Suzuki, Michito*; Yanagi, Yuki*; Hirayama, Motoaki*; Khanh, N.*; Karube, Kosuke*; et al.

Nature Physics, 19(7), p.961 - 968, 2023/07

https://doi.org/10.1038/s41567-023-02017-3

Characteristics in trace elements compositions of tephras (B-Tm and To-a) for identification tools

Nara, Fumiko*; Yokoyama, Tatsunori; Yamasaki, Shinichi*; Minami, Masayo*; Asahara, Yoshihiro*; Watanabe, Takahiro; Yamada, Kazuyoshi*; Tsuchiya, Noriyoshi*; Yasuda, Yoshinori*

Geochemical Journal, 55(3), p.117 - 133, 2021/00

https://doi.org/10.2343/geochemj.2.0619

The absolute date of the Millennium Eruption (ME) of Changbaishan Volcano is widely recognized as AD 946. The Baegdosan-Tomakomai (B-Tm) tephra dispersed during the ME is a robust-age key bed. In order to identify the tephra, refractive index and major-element compositions of volcanic glass shards are conventionally used. However, trace-element analysis has been rarely carried out, especially for rare-earth elements (REEs) and for tephra layer bulk sediments. Here we present the datasets of major- and trace-element compositions datasets for the glass shards and bulk sediments of the B-Tm and Towada caldera eruptions (To-a) tephra deposits from the Lake Ogawara sediment core, Tohoku region, northern Japan. The depth profiles of the major and trace elements show the significant peaks for the KO and some trace elements (Zn, Rb, Zr, Nb, Sn, Y, La, Ce, Nd, Th, and U) at the B-Tm tephra layer in the Lake Ogawara sediment core, but no peaks of these elements at the To-a tephra layer. High concentrations of the trace elements in the B-Tm tephra layer were observed in individual glass shards as well as in the bulk sediment. These concentrations are highlighted by the elemental abundance pattern normalized by the crustal abundance. The elemental pattern in individual glass shards from other Japanese tephras showed significant differences from those of the B-Tm tephra, especially in REEs compositions. The trace-element compositions of the glass shards and bulk sediment show strong advantages for distinguishing the B-Tm tephra from other Japanese tephras.

Development of divertor simulation research in the GAMMA 10/PDX tandem mirror

Nakashima, Yosuke*; Sakamoto, Mizuki*; Yoshikawa, Masayuki*; Oki, Kensuke*; Takeda, Hisahito*; Ichimura, Kazuya*; Hosoi, Katsuhiro*; Hirata, Mafumi*; Ichimura, Makoto*; Ikezoe, Ryuya*; et al.

Proceedings of 25th IAEA Fusion Energy Conference (FEC 2014) (CD-ROM), 8 Pages, 2014/10

Prevention of false alarms from automatic fire alarm system in the Tokai Reprocessing Plant

Ishii, Takahiro; Shimizu, Kazuyuki; Sakai, Katsumi; Inami, Shinichi

Dai-7-Kai Saishori, Risaikuru Bukai Semina Tekisuto, p.172 - 173, 2011/01

The automatic fire alarm system installed in the Tokai Reprocessing Plant consists of more than 5,000 detectors in about 40 facilities for the moment. In this system, 57 non-fire cases have occurred for about 10 years from January 2001 to December 2010. and about half of these cases was due to the condensation of water vapor generated on the sensor. Therefore, the prevention of condensation is necessary to reduce such false alarms, and the measure for prevention of condensation has been taken by installing a mount for the detector basement. This mount facilitates that the detector does not contact directly to the surface of ceiling where is likely to change an environment due to changeable temperature and humidity. As a result, false alarms caused by condensation have not been found on the detectors with the mounts. This paper reports the details of the improved fire alarm system, and cause/measures for false alarms.

Development of maintenance technology for rotating equipment; Condition based maintenance by shock pulse method

Takeuchi, Kenji; Sanyoshi, Hirotaka; Fukuari, Yoshihiro; Inami, Shinichi

Proceedings of 7th International Conference on NDE in relation to Structural Integrity for Nuclear and Pressurized Components (CD-ROM), p.37 - 44, 2010/00

In the Tokai Reprocessing Plant (TRP), lots of blowers are used for enclosing radioactive materials in a controlled area, and pumps are used for circulating cooling water to keep temperature under appropriate conditions of vessels, which contain high-level radioactive liquid waste. These rotating equipments play an important role in safety management of the nuclear facilities, where they are required stable conditions all the time. To improve the reliability of rotating equipments, the condition based maintenance for detecting the deterioration is one of the effective measures. According to the analyses of the past maintenance data obtained in TRP, it has been found that about 90% troubles related to the rotating equipment are caused in the bearing works, in which the lubrication was defective in almost every case. So, it is very important for stable operation of the rotating equipment to monitor the lubrication conditions in bearings. The vibration method facilitates to detect defects and abrasion of bearings by measuring a vibration signal. However, this method has a disadvantage that quantitative management for the lubrication conditions of bearings is not possible. Therefore, the shock pulse method, which is widely used for diagnosis of the bearings, is applied to assess the deterioration of rolling bearing. The shock pulse method can detect the change of the lubrication condition and the presence of defects in bearings, by a pressure wave generated from rotating rolling bearing. The method can also evaluate the oil slick thickness and the condition of deterioration in the bearing. As one of maintenance activities performed after monitoring, replenishment with a suitable amount of oil for a lubricant was able to be conducted with a proper timing. As a result, the number of the troubles on bearings has significantly reduced because proper maintenance for keeping the oil slick thickness can be carried out, which resulted in stable operation of the rotary equipmen

Preventive countermeasure of air purge tube blocking using a humidifier in the Tokai Reprocessing Plant

Yasuo, Kiyoshi; Seto, Nobuhiko; Watahiki, Seiichi; Iwasaki, Shogo; Inami, Shinichi

Nihon Hozen Gakkai Dai-6-Kai Gakujutsu Koenkai Yoshishu, p.506 - 509, 2009/08

The air purge method is applied to measure a liquid level and its density of a radioactive solution in a tank in the Tokai reprocessing plant. In this method, air purge tubes soaked in nitric acid solution are often blocked by depositing salt of nitrate. Dried air is usually used for the air purge system and this can be one of the reasons for generating salt on the tube point. Therefore, a series of experiment using a humidifier to humidify the air has been performed to prevent the blocking with salt, and the effect has been experimentally confirmed.

Maintenance management of emergency power supply equipment (uninterruptible power supply) in Tokai reprocessing plant

Nishida, Kyosuke; Hiyama, Hisao; Shibata, Satomi; Iwasaki, Shogo; Inami, Shinichi

Nihon Hozen Gakkai Dai-6-Kai Gakujutsu Koenkai Yoshishu, p.294 - 297, 2009/08

Uninterruptible power supply systems are installed in the Tokai reprocessing plant in preparation for the emergency case that the commercial power supply is stopped by an accidental or intentional interruption in the supply of electricity. The uninterruptible power supply system particularly provides a temporary power source to the important devices for the radiation control of nuclear critical monitoring in the plant. Thus, the system is potentially important and essential for nuclear plants. The paper repots the current activities such as regular inspections, replacement of parts and system update, to maintain the function of uninterruptible power supply systems.

Electronic structure and magnetism of CaMnRuO thin films

Terai, Kota; Yoshii, Kenji; Takeda, Yukiharu; Fujimori, Shinichi; Saito, Yuji; Owada, Kenji; Inami, Toshiya; Okane, Tetsuo; Arita, Masashi*; Shimada, Kenya*; et al.

Journal of Magnetism and Magnetic Materials, 310(2, Part2), p.1070 - 1072, 2007/03

We have studied the electronic and magnetic properties of epitaxially grown CaMnRuO (x = 1.0, 0.5) thin films by X-ray magnetic circular dichroism (XMCD) and hard X-ray photoemission spectroscopy (HXPES). The XMCD studies indicated that the spin moments of Mn and Ru are aligned in the opposite directions. The HXPES spectra indicated the Ru 4d states at around the Fermi edge (E) and the Mn 3d states below E. From these results, we propose that the localized Mn 3d t states and the itinerant Ru 4d t band are antiferromagnetically coupled and give rise to ferromagnetism, in analogy with the mechanism proposed for the double perovskite oxides such as SrFeMoO.

None

Inami, Shinichi; Nogami, Takashi; Maki, Akira; Ogata, Yoshiaki; Takeshita, Kenji*; Sazarashi Masami*; Kumagai, Mikio*

Donen Giho, (98), p.32 - 42, 1996/06

https://jopss.jaea.go.jp/pdfdata/PNC-TN1340-96-002.pdf

None

Development of silver-impregnated hydrophobic adsorbent for removal of radioactive iodine

Inami, Shinichi; ; *; *

Proceedings of 4th International Conference on Nuclear Fuel Reprocessing and Waste Management (RECOD '94), 0 Pages, 1994/00

None