Investigation of the ground-state spin inversion in the neutron-rich Cl isotopes

Linh, B. D.*; Corsi, A.*; Gillibert, A.*; Obertelli, A.*; Doornenbal, P.*; Barbieri, C.*; Chen, S.*; Chung, L. X.*; Duguet, T.*; Gmez-Ramos, M.*; et al.

Physical Review C, 104(4), p.044331_1 - 044331_16, 2021/10

https://doi.org/10.1103/PhysRevC.104.044331

no abstracts in English

Quasifree neutron knockout reaction reveals a small -Orbital component in the Borromean nucleus B

Yang, Z. H.*; Kubota, Yuki*; Corsi, A.*; Yoshida, Kazuki; Sun, X.-X.*; Li, J. G.*; Kimura, Masaaki*; Michel, N.*; Ogata, Kazuyuki*; Yuan, C. X.*; et al.

Physical Review Letters, 126(8), p.082501_1 - 082501_8, 2021/02

https://doi.org/10.1103/PhysRevLett.126.082501

A quasifree (,) experiment was performed to study the structure of the Borromean nucleus B, which had long been considered to have a neutron halo. By analyzing the momentum distributions and exclusive cross sections, we obtained the spectroscopic factors for and orbitals, and a surprisingly small percentage of 9(2)% was determined for . Our finding of such a small component and the halo features reported in prior experiments can be explained by the deformed relativistic Hartree-Bogoliubov theory in continuum, revealing a definite but not dominant neutron halo in B. The present work gives the smallest - or -orbital component among known nuclei exhibiting halo features and implies that the dominant occupation of or orbitals is not a prerequisite for the occurrence of a neutron halo.

Spontaneous debonding behaviour of reinforcement fine particles in aluminium; Toward high-strength metallic materials development

Toda, Hiroyuki*; Tsuru, Tomohito; Yamaguchi, Masatake; Matsuda, Kenji*; Shimizu, Kazuyuki*; Hirayama, Kyosuke*

Kagaku, 75(10), p.48 - 53, 2020/10

Highly-concentrated precipitations play therefore dominant role in mechanical properties and hydrogen embrittlement of aluminum alloys. It has been considered that the coherent interface between matrix and precipitation does not contribute to the crack initiation and embrittlement due to its coherency. Here, we discovered the origin of unprecedented quasi-cleavage fracture mode. Hydrogen partitioning at various defect sites is investigated comprehensively combined with experiment, theory and first-principles calculations. We demonstrate that despite low excess free volume, the aluminum-precipitation interface is more preferable trap site than void and grain boundary. The cohesivity of the interface deteriorates significantly with increasing occupancy while hydrogen atoms are trapped stably up to extremely high occupancy equivalent to spontaneous cleavage.

The Possible transition mechanism for the meta-stable phase in the 7xxx aluminium

Bendo, A.*; Matsuda, Kenji*; Nishimura, Katsuhiko*; Nunomura, Norio*; Tsuchiya, Taiki*; Lee, S.*; Marioara, C. D.*; Tsuru, Tomohito; Yamaguchi, Masatake; Shimizu, Kazuyuki*; et al.

Materials Science and Technology, 36(15), p.1621 - 1627, 2020/09

https://doi.org/10.1080/02670836.2020.1821323

Metastable phases in aluminum alloys are the primary nano-scale precipitates which have the biggest contribution to the increase in the tangible mechanical properties. The continuous increase in hardness in the 7xxx aluminum alloys is associated with the phase transformation from clusters or GP-zones to the metastable phase. The transformation which is structural and compositional should occur following the path of the lowest activation energy. This work is an attempt to gain insight into how the structural transformation may occur based on the shortest route of diffusion for the eventual structure to result in that of phase. However, for the compositional transformation to occur, the proposed mechanism may not stand, since it is a prerequisite for the atoms to be at very precise positions in the aluminum lattice, at the very beginning of structural transformation, which may completely differ from that of the GP-zones atomic arrangements.

An Unreported precipitate orientation relationship in Al-Zn-Mg based alloys

Bendo, A.*; Matsuda, Kenji*; Lervik, A.*; Tsuru, Tomohito; Nishimura, Katsuhiko*; Nunomura, Norio*; Holmestad, R.*; Marioara, C. D.*; Shimizu, Kazuyuki*; Toda, Hiroyuki*; et al.

Materials Characterization, 158, p.109958_1 - 109958_7, 2019/12

https://doi.org/10.1016/j.matchar.2019.109958

Characterization of precipitates in Al-Zn-Mg alloys, using a combination of electron diffraction, bright field transmission electron microscopy and atomic scale scanning transmission electron microscopy imaging revealed the presence of an unreported orientation relationship between the -MgZn phase and the Al lattice with the following orientation relationship (0001) (120) and () (001), plate on (120). The precipitate interfaces were observed and analyzed along two projections 90 to one-another. The precipitate coarsening was through the common thickening ledge mechanism. The ledges were significantly stepped along one lateral direction. An interface relaxation model using density functional theory was carried out to explain the precipitate behavior.

Microstructure evolution in a hydrogen charged and aged Al-Zn-Mg alloy

Bendo, A.*; Matsuda, Kenji*; Lee, S.*; Nishimura, Katsuhiko*; Toda, Hiroyuki*; Shimizu, Kazuyuki*; Tsuru, Tomohito; Yamaguchi, Masatake

Materialia, 3, p.50 - 56, 2018/11

https://doi.org/10.1016/j.mtla.2018.09.035

Status of breakup reaction theory

Ogata, Kazuyuki*; Matsumoto, Takuma*; Hashimoto, Shintaro; Minomo, Kosho*; Egami, Tomoaki*; Iseri, Yasunori*; Kono, Michio*; Chiba, Satoshi; Bertulani, C. A.*; Shimizu, Yoshifumi*; et al.

Journal of Physics; Conference Series, 312, p.082008_1 - 082008_10, 2011/09

https://doi.org/10.1088/1742-6596/312/8/082008

Recent studies on breakup reactions with the continuum-discretized coupled channels method are reviewed. The topics covered are: four-body breakup processes for He induced reaction, dynamical relativistic effects on coulomb breakup, microscopic description of projectile breakup processes, description of ternary processes (new triple- reaction rate) and new approach to inclusive breakup processes.

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

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

Nihon Hozen Gakkai Dai-6-Kai Gakujutsu Koenkai Yoshishu, p.289 - 293, 2009/08

The automatic fire alarm system installed in the Tokai Reprocessing Plant consists of more than 5000 detectors in about 40 facilities for the moment. In this system, 51 non-fire cases have occurred for 8 years; 2001 Jan. to 2009 May, 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.

Grid computing supporting system on ITBL project

Higuchi, Kenji; Imamura, Toshiyuki*; Suzuki, Yoshio; Shimizu, Futoshi; Machida, Masahiko; Otani, Takayuki; Hasegawa, Yukihiro*; Yamagishi, Nobuhiro*; Kimura, Kazuyuki*; Aoyagi, Tetsuo; et al.

Lecture Notes in Computer Science 2858, p.245 - 257, 2003/00

Prototype of the middleware for Grid project promoted by national institutes in Japan has been developed. Key technologies that are indispensable for construction of virtual organization were already implemented onto the prototype of middleware and examined in practical computer/network system from a view point of availability. In addition several kinds of scientific applications are being executed on the prototype system. It seems that successful result in the implementation of those technologies such as security infrastructure, component programming and collaborative visualization in practical computer/network systems means significant progress in Science Grid in Japan.

Development of Tokai Reprocessing Plant Maintenance Support System (TORMASS) in the Tokai Reprocessing Plant

Sakai, Katsumi; Tomita, Tsuneo; Shimizu, Kazuyuki

no journal, , 

The maintenance work of many equipments such as mechanical, electrical and instrumentations installed in Tokai Reprocessing Plant has been performed more then 10,000 times per year and about 90% of maintenances were preventive work. For the maintenance management, optimization of maintenance information is required. Therefore, the aim of construction of suitable maintenance management system, Tokai Reprocessing Plant Maintenance Support System(TORMASS) was developed from 1985 to 1992. About 24,000 equipments of specifications and about 261,000 maintenance detail were registered in this system. TORMASS has been used for the repair, inspection and replacement of equipment.