Optimization of mechanical properties in aluminum alloys hydrogen partitioning control

Toda, Hiroyuki*; Yamaguchi, Masatake; Matsuda, Kenji*; Shimizu, Kazuyuki*; Hirayama, Kyosuke*; Su, H.*; Fujihara, Hiro*; Ebihara, Kenichi; Itakura, Mitsuhiro; Tsuru, Tomohito; et al.

Tetsu To Hagane, 105(2), p.240 - 253, 2019/02

https://doi.org/10.2355/tetsutohagane.TETSU-2018-083

no abstracts in English

Efficient extreme ultraviolet emission from one-dimensional spherical plasmas produced by multiple lasers

Yoshida, Kensuke*; Fujioka, Shinsuke*; Higashiguchi, Takeshi*; Ugomori, Teruyuki*; Tanaka, Nozomi*; Ohashi, Hayato*; Kawasaki, Masato*; Suzuki, Yuhei*; Suzuki, Chihiro*; Tomita, Kentaro*; et al.

Applied Physics Express, 7(8), p.086202_1 - 086202_4, 2014/08

https://doi.org/10.7567/APEX.7.086202

We demonstrate high conversion efficiency for extreme ultraviolet (EUV) emission at 6.5-6.7 nm from multiple laser beam-produced one-dimensional spherical plasmas. Multiply charged-state ions produce strong resonance emission lines, which combine to yield intense unresolved transition arrays in Gd, Tb, and Mo. The maximum in-band EUV conversion efficiency was observed to be 0.8%, which is one of the highest values ever reported due to the reduction of plasma expansion loss.

Enhancement of IR light emission from -FeSi nanocrystals embedded in Si

Maeda, Yoshihito; Nishimura, Kentaro*; Nakajima, Takahito*; Matsukura, Bui*; Narumi, Kazumasa; Sakai, Seiji

Physica Status Solidi (C), 9(10-11), p.1888 - 1891, 2012/10

https://doi.org/10.1002/pssc.201200072

We have systematically investigated photoluminescence (PL) properties of -phase nanocrystals which are formed by a phase transition from metastable -FeSi with a Fluorite structure to -FeSi, and succeeded in enhancement of the PL intensity in the optimum conditions of double annealing process. For the PL enhancement, the time of postannealing at 800C is dominated by the time of the preannealing at 400 or 500C which is related to amount of the -phase. After discussing some possible factors, we speculate that the PL enhancement observed in this study may be attributed mainly to improvement of the interface condition between the nanocrystal and Si, because the crystallographic epitaxial relationship among the phases, Si(111)//(111)//(202)/(220) can be maintained during precipitation of the nanocrystal on Si(111).

Transmission imaging and strain mapping in the vicinity of internal crack tip using synchrotron white X-ray

Shibano, Junichi*; Kajiwara, Kentaro*; Kiriyama, Koji*; Shobu, Takahisa; Suzuki, Kenji*; Nishimura, Suguru*; Miura, Setsuo*; Kobayashi, Michiaki*

Materials Science Forum, 638-642, p.2476 - 2481, 2010/01

Irradiation effect of 14 MeV neutron on interlaminar shear strength of glass fiber reinforced plastics

Nishimura, Arata*; Hishinuma, Yoshimitsu*; Seo, Kazutaka*; Tanaka, Teruya*; Muroga, Takeo*; Nishijima, Shigehiro*; Katagiri, Kazumune*; Takeuchi, Takao*; Shindo, Yasuhide*; Ochiai, Kentaro; et al.

AIP Conference Proceedings 824, p.241 - 248, 2005/09

https://doi.org/10.1063/1.2192357

Design activity of International Thermonuclear Experimental Reactor clarifies intense neutron streaming from ports for neutral beam injectors. Energy spectrum of the streaming is very wide and 14 MeV neutron and ray are the typical radiations. Large amount of glass fiber reinforced plastics will be used in a superconducting magnet system as an electric insulation material and a support structure, for such organic material is easy to manufacture, and light and cheap. In this report, effects of 14 MeV neutron and ray irradiation on interlaminar shear strength and fracture mode are investigated using G-10CR small specimen of which configuration was proposed as a standard for evaluation of the interlaminar shear strength.

Growth of -FeSi nanocrystals by phase transition and enhancement of light emission property

Nishimura, Kentaro*; Nakajima, Takahito*; Nagasawa, Yoshiyuki*; Narumi, Kazumasa; Maeda, Yoshihito*

no journal, , 

Development of an inspection probing system for the case of reactor melt down accident

Ito, Fuyumi; Nishimura, Akihiko; Tomiyoshi, Kentaro; Ito, Chikara; Sugiyama, Akira

no journal, , 

An innovative probing system should be required for the case of reactor core melt down accidents. In the Fukushima Daiichi BWRs, molten debris might drop in the pedestal under the reactor pressure vessel. Due to the high radioactive situation, the probing system is going to be inserted into the pedestal by a remote controlled robotic arm. We are planning the probing system which consists of optics of Laser Induced Breakdown Spectroscopy (LIBS), a waterproof view scope, radiation resistant optical fibers, radiation dose monitor, and so on. The purpose of LIBS is to analyze the composition of the molten debris. That of the waterproof view scope is to know its position in the pedestal. The following paragraph mentions each outline which we did until now.

Development of an inspection probing system using laser monitoring for aging power plants

Ito, Fuyumi; Nishimura, Akihiko; Tomiyoshi, Kentaro

no journal, , 

An optical fiber coupling device for maintenance was developed. A function such as observation of target object by wide-angle image, and the technique such as the elemental analysis by spectroscope and laser were built in the very compact device. Therefore, this device would permit wide-angle image and laser processing at oppressive conditions. The target object was measured and observed by these functions. Finally, industry application of this device was discussed.

Development of in-vessel inspection technology using remote imaging and spectroscopy, 3-1; Search technique in water

Ito, Fuyumi; Nishimura, Akihiko; Tomiyoshi, Kentaro; Ito, Chikara; Daido, Hiroyuki; Sugiyama, Akira

no journal, , 

An innovative probing system should be required for the case of reactor core melt down accidents. In the Fukushima Daiichi BWRs, molten debris might drop in the pedestal under the reactor pressure vessel. Due to the high radioactive situation, the probing system is going to be inserted into the pedestal by a remote controlled robotic arm. We are planning the probing system which consists of optics of Laser Induced Breakdown Spectroscopy (LIBS), a waterproof view scope, radiation resistant optical fibers, radiation dose monitor, and so on. The purpose of LIBS is to analyze the composition of the molten debris. That of the waterproof view scope is to know its position in the pedestal. The following paragraph mentions each outline which we did until now.

Numerical simulation of high heat flux pool boiling using PLIC-VOF method

Nagasaki, Takao*; Aoki, Takayuki*; Sugihara, Kenta; Nishimura, Masato*; Nakashima, Akira*; Nakamura, Kazuhiro*; Marui, Kentaro*

no journal, , 

Boiling is a gas-liquid two-phase phenomenon of practical importance used in nuclear power generation and equipment cooling. Still, its numerical simulation has not yet been fully developed due to its complex nature involving phase changes. In this study, numerical simulations of pool nucleate boiling, the most basic form of boiling, are performed for a realistic case with many foaming points. The PLIC-VOF method, a sharp interface method, is used because high lattice resolution is required to reproduce the fine boiling structure near the superheated wall, especially for high heat flux boiling. For the solution of the pressure field, a weakly compressible fluid model was used in this study because the Poisson equation solver for the pressure in incompressible flows must be faster and larger in scale. In addition, micro-liquid film evaporation at the bottom of vapor bubbles growing on the wall surface is modeled and incorporated into the calculations. Nucleate boiling was simulated using the above calculation method, and the bubble behavior and wall heat flux were compared with existing experimental results to examine the validity of this simulation.