Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 84

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Reaction path and product analysis of sodium-water chemical reactions using laser diagnostics

Deguchi, Yoshihiro*; Muranaka, Ryota*; Kamimoto, Takahiro*; Takagi, Taku*; Kikuchi, Shin; Kurihara, Akikazu

Applied Thermal Engineering, 114, p.1319 - 1324, 2017/03

 Times Cited Count:2 Percentile:13.03(Thermodynamics)

The purpose of this study aims to clarify the gas phase sodium-water reaction path and reaction products quantitatively. The counter-flow diffusion experiment device was employed to analyze the reaction path and reaction products using laser diagnostics. The main product of sodium-water reaction was determined to be NaOH and the sodium oxide was not notably measured compared with NaOH.

Journal Articles

Encapsulating mobile proton carriers into structural defects in coordination polymer crystals; High anhydrous proton conduction and fuel cell application

Inukai, Munehiro*; Horike, Satoshi*; Itakura, Tomoya*; Shinozaki, Ryota*; Ogiwara, Naoki*; Umeyama, Daiki*; Nagarker, S.*; Nishiyama, Yusuke*; Malon, M.*; Hayashi, Akari*; et al.

Journal of the American Chemical Society, 138(27), p.8505 - 8511, 2016/07

 Times Cited Count:130 Percentile:95.54(Chemistry, Multidisciplinary)

Journal Articles

Reaction path and product analysis of sodium-water chemical reactions using laser diagnostics

Deguchi, Yoshihiro*; Muranaka, Ryota*; Kamimoto, Takahiro*; Takagi, Taku*; Kikuchi, Shin; Kurihara, Akikazu

Proceedings of 3rd International Workshop on Heat Transfer Advances for Energy Conservation and Pollution Control (IWHT 2015) (CD-ROM), 6 Pages, 2015/10

The purpose of this study aims to clarify the gas phase sodium-water reaction path and reaction products quantitatively. The counter-flow diffusion experiment device was employed to analyze the reaction path and reaction products using laser diagnostics. The main product of sodium-water reaction was determined to be NaOH and the sodium oxide was not notably measured compared with NaOH.

Journal Articles

Observation of dynamics and modification of solid surface using a picosecond soft X-ray laser

Nishikino, Masaharu; Kawachi, Tetsuya; Hasegawa, Noboru; Ishino, Masahiko; Minami, Yasuo*; Suemoto, Toru*; Onishi, Naofumi*; Ito, Atsushi*; Sato, Katsutoshi*; Faenov, A.*; et al.

X-Ray Lasers and Coherent X-Ray Sources; Development and Applications XI (Proceedings of SPIE, Vol.9589), p.958902_1 - 958902_7, 2015/09

Journal Articles

Hydrodynamics driven by ultrashort laser pulse; Simulations and the optical pump - X-ray probe experiment

Inogamov, N. A.*; Zhakhovsky, V. V.*; Hasegawa, Noboru; Nishikino, Masaharu; Yamagiwa, Mitsuru; Ishino, Masahiko; Agranat, M. B.*; Ashitkov, S. I.*; Faenov, A. Y.*; Khokhlov, V. A.*; et al.

Applied Physics B, 119(3), p.413 - 419, 2015/06

 Times Cited Count:6 Percentile:34.58(Optics)

Journal Articles

Experimental and numerical reaction analysis on sodium-water chemical reaction field

Deguchi, Yoshihiro*; Takata, Takashi*; Yamaguchi, Akira*; Kikuchi, Shin; Ohshima, Hiroyuki

Mechanical Engineering Journal (Internet), 2(1), p.14-00029_1 - 14-00029_11, 2015/02

In a sodium-cooled fast reactor (SFR), liquid sodium is used as a heat transfer fluid because of its excellent heat transport capability. On the other hand, it has strong chemical reactivity with water vapor. One of the design basis accidents of the SFR is the water leakage into the liquid sodium flow by a breach of heat transfer tubes. This process ends up damages on the heat transport equipment in the SFR. Therefore, the study on sodium-water chemical reactions is of paramount importance for security reasons. This study aims to clarify the sodium-water reaction mechanisms using an elementary reaction analysis. From analytical results, the main reaction was Na + H$$_{2}$$O = NaOH + H at gas-phase reaction.

Journal Articles

Observation of femtosecond laser ablation on Tungsten by using soft X-ray reflection and interference imaging

Nishikino, Masaharu; Hasegawa, Noboru; Tomita, Takuro*; Eyama, Tsuyoshi*; Kakimoto, Naoya*; Onishi, Naofumi*; Ito, Atsushi*; Baba, Motoyoshi*; Minami, Yasuo*; Kawachi, Tetsuya; et al.

Reza Gakkai Dai-471-Kai Kenkyukai Hokoku; Tanhacho Ryoshi Bimu Hassei To Sono Oyo, p.9 - 12, 2014/12

no abstracts in English

Journal Articles

Submicron scale image observation with a grazing incidence reflection-type single-shot soft X-ray microscope

Baba, Motoyoshi*; Nishikino, Masaharu; Hasegawa, Noboru; Tomita, Takuro*; Minami, Yasuo*; Takei, Ryota*; Yamagiwa, Mitsuru; Kawachi, Tetsuya; Suemoto, Toru

Japanese Journal of Applied Physics, 53(8), p.080302_1 - 080302_4, 2014/08

 Times Cited Count:7 Percentile:31.01(Physics, Applied)

A grazing incidence reflection-type soft X-ay microscope, using a Fresnel zone plate and a soft X-ray laser with wavelength 13.9 nm and pulse width 7 ps, was developed. Submicron size groove structures made on a Pt film were clearly captured at a single shot exposure, with spatial resolution of about 360 nm. A wide field view of 100 $$mu$$m square was secured under the Kohler illumination. This microscope also had a large depth of focus of more than 100 $$mu$$m and was proven to have a sufficient performance for observing surface morphological changes.

Journal Articles

Time-resolved soft X-ray imaging of femtosecond laser ablation process in metals

Tomita, Takuro*; Nishikino, Masaharu; Hasegawa, Noboru; Minami, Yasuo*; Takei, Ryota*; Baba, Motoyoshi*; Eyama, Tsuyoshi*; Takayoshi, Shodai*; Kaihori, Takeshi*; Morita, Toshimasa; et al.

Journal of Laser Micro/Nanoengineering, 9(2), p.137 - 142, 2014/06

 Times Cited Count:5 Percentile:29.68(Nanoscience & Nanotechnology)

Femtosecond laser ablation processes on platinum, gold, and tungsten were observed by the single shot pump and probe reflective imaging using a soft X-ray laser probe. To avoid the timing error due to the jitter, we adopted a posteriori correction technique by simultaneous measurement of timing between the pump and probe pulses for every single shot, using a soft X-ray streak camera. A clear difference was found in the temporal behavior of the dynamical response of the soft X-ray reflectivity depending on the irradiated laser fluence in these three materials. On the other hand, the narrow dark rings were found in Pt and W, while an additional bright ring was found outside the dark disk in Au. Our result gives the experimental data comparable with various numerical simulations.

Journal Articles

Performance of a total absorption clover detector for $$Q_{beta}$$ measurements of neutron-rich nuclei far from the $$beta$$-stability line

Hayashi, Hiroaki*; Shibata, Michihiro*; Asai, Masato; Osa, Akihiko; Sato, Tetsuya; Koizumi, Mitsuo; Kimura, Atsushi; Oshima, Masumi*

Nuclear Instruments and Methods in Physics Research A, 747, p.41 - 51, 2014/05

 Times Cited Count:10 Percentile:61.24(Instruments & Instrumentation)

To measure $$beta$$-decay energy $$Q_{beta}$$ of short-lived fission products with good accuracy and high efficiency, we have developed a new total absorption clover detector and demonstrated its performance. Using a large-volume clover-type Ge detector having a through-hole in its center, we could measure total absorption spectra of $$beta$$ + $$gamma$$ rays with extremely high efficiency and high energy resolution, and could determine $$Q_{beta}$$ values with $$pm$$30 keV accuracy. Using this detector, we have determined the $$Q_{beta}$$ values of $$^{166}$$Eu and $$^{165}$$Gd for the first time, and of $$^{160-165}$$Eu and $$^{163}$$Gd with better accuracies. In addition, we have observed a new isomeric state in $$^{163}$$Gd, and determined its half-life and excitation energy.

Journal Articles

Temperature dependence of electric conductivities in femtosecond laser modified areas in silicon carbide

Deki, Manato*; Oka, Tomoki*; Takayoshi, Shodai*; Naoi, Yoshiki*; Makino, Takahiro; Oshima, Takeshi; Tomita, Takuro*

Materials Science Forum, 778-780, p.661 - 664, 2014/02

 Times Cited Count:2 Percentile:72.87

no abstracts in English

Journal Articles

Single event gate rupture in SiC MOS capacitors with different gate oxide thicknesses

Deki, Manato*; Makino, Takahiro; Kojima, Kazutoshi*; Tomita, Takuro*; Oshima, Takeshi

Materials Science Forum, 778-780, p.440 - 443, 2014/02

 Times Cited Count:2 Percentile:82.41

no abstracts in English

Journal Articles

Development of soft X-ray microscopy using Fresnel zone plate for observation of laser-induce surface dynamics

Nishikino, Masaharu; Baba, Motoyoshi*; Suemoto, Toru; Hasegawa, Noboru; Ishino, Masahiko; Kaihori, Takeshi; Kawachi, Tetsuya; Yamagiwa, Mitsuru

X-Ray Lasers 2012; Springer Proceedings in Physics, Vol.147, p.199 - 202, 2014/00

 Times Cited Count:0 Percentile:0

The dynamical processes of the laser-induced surface modifications such as laser ablation come to attract much attention for the micro processing by the ultra-short laser pulse. It is difficult to observe these phenomena directly, because they are non-repetitive, unrepeatable, and occur very rapidly (pico-second) in a very small (micron) area. In order to observe the detailed laser-ablation process, we have developed the proto-type reflected soft X-ray microscopy using the Fresnel zone plate. The experimental setup and spatial resolution of the X-ray microscopy will be presented.

Journal Articles

Reaction path analysis to sodium-water chemical reaction field using laser diagnostics

Tamura, Kenta*; Deguchi, Yoshihiro*; Muranaka, Ryota*; Kusano, Koji*; Takata, Takashi*; Kikuchi, Shin; Kurihara, Akikazu

Proceedings of 24th International Symposium on Transport Phenomena (ISTP-24) (USB Flash Drive), 5 Pages, 2013/11

The purpose of this study aims to clarify the gas phase sodium-water reaction path and reaction products. The counter-flow diffusion experiment device is in the form of introducing the argon-based water vapor from the top of depressurized reaction chamber to the liquid sodium pool. Na, Na$$_{2}$$, H$$_{2}$$O, and reaction products in the counter-flow sodium-water reaction field were measured using laser diagnostics. The temperature controlled device was also improved to reduce the condensation of Na in the reaction zone for the better measurement performance. The main product in the sodium-water reaction was determined to be NaOH from the experimental results and its reaction path was discussed using Na-H$$_{2}$$O elementary reaction analysis.

Journal Articles

Application of laser diagnostics to sodium-water chemical reaction field

Deguchi, Yoshihiro*; Tamura, Kenta*; Muranaka, Ryota*; Kusano, Koji*; Kikuchi, Shin; Kurihara, Akikazu

Reza Kenkyu, 41(11), p.927 - 931, 2013/11

In a sodium-cooled fast reactor (SFR), liquid sodium is used as a heat transfer fluid because of its excellent heat transport capability. On the other hand, it has strong chemical reactivity with water vapor. One of the design basis accidents of the SFR is the water leakage into the liquid sodium flow by a breach of heat transfer tubes. Therefore the study on sodium-water chemical reactions is of paramount importance for security reasons. This study aims to clarify the sodium-water reaction mechanisms using laser diagnostics. The measurement results show that the sodium-water reaction proceeds mainly by the reaction Na + H$$_{2}$$O = NaOH + H and the main product is NaOH from this reaction.

Journal Articles

Measurement of femtosecond laser ablation by soft X-ray laser interferometory and reflective imaging

Nishikino, Masaharu; Hasegawa, Noboru; Ishino, Masahiko; Yamagiwa, Mitsuru; Kawachi, Tetsuya; Minami, Yasuo*; Terakawa, Kota*; Takei, Ryota*; Baba, Motoyoshi*; Suemoto, Toru; et al.

JAEA-Conf 2013-001, p.16 - 19, 2013/09

The dynamics of the femtosecond laser ablation is still not clear at the early stage. Several studies on the time-resolved imaging of femtosecond laser ablation process have been performed on various materials. In this study, we have demonstrated a pump and probe imaging of the metal surface morphology during the femtosecond laser ablation by using the laser-driven plasma induced soft X-ray laser (SXRL) as a probe beam. The pumping laser used for ablation was a Ti:Sapphire laser system based on chirped pulse amplification. The pump beam had a Gaussian profile and the focal spot size on the metal surface was about 70 micron at FWHM. The dependence for the pump laser fluence of the ablation surface expansion and the surface condition (roughness and density gradient) were observed from the soft X-ray interferogram and reflective image, respectively.

Journal Articles

Observation of the nano-scale surface dynamics of femtosecond laser ablation by time-resolved soft X-ray imaging technique

Nishikino, Masaharu; Hasegawa, Noboru; Tomita, Takuro*; Minami, Yasuo*; Takei, Ryota*; Baba, Motoyoshi*; Eyama, Tsuyoshi*; Takayoshi, Shodai*; Kawachi, Tetsuya; Hatomi, Daiki*; et al.

Proceedings of SPIE, Vol.8849, p.88490E_1 - 88490E_6, 2013/09

 Times Cited Count:2 Percentile:73.17

We have developed the pump and probe interferometer and reflective imaging technique of the metal surfaces during the femtosecond laser ablation by using the laser-driven soft X-ray laser at the wavelength of 13.9 nm. The pumping laser used for ablation was a Ti: Sapphire laser pulse with the duration of 80 fs pulse at a central wavelength of 795 nm, and had a gaussian spatial profile. By using the X-ray imaging technique, the time resolved image of nano-scaled ablation dynamics of the platinum and the gold pumped by a femtosecond laser pulse was obtained.

Journal Articles

Ground-state configuration of the $$N=157$$ nucleus $$^{259}$$No

Asai, Masato; Tsukada, Kazuaki; Sakama, Minoru*; Haba, Hiromitsu*; Ichikawa, Takatoshi*; Ishii, Yasuo; Toyoshima, Atsushi; Ishii, Tetsuro; Nishinaka, Ichiro; Nagame, Yuichiro; et al.

Physical Review C, 87(1), p.014332_1 - 014332_6, 2013/01

 Times Cited Count:6 Percentile:43.85(Physics, Nuclear)

The spin-parity and neutron configuration of the ground state of $$^{259}$$No have been identified through $$alpha$$-decay spectroscopy. The $$^{259}$$No is the nucleus with the largest neutron number whose spin-parities and single-particle configurations have ever been identified. The neutron 9/2$$^{+}$$[615] configuration was assigned to the ground state of $$^{259}$$No as well as to the 231.4 keV level in $$^{255}$$Fm. This allowed us to establish energy spacings and order of the neutron single-particle orbitals in such heaviest nuclear region. The appearance of the 9/2$$^{+}$$[615] ground state at $$N$$=157 implies that the order of the neutron orbitals between the $$N$$=152 and 162 deformed shell gaps should change considerably with increasing neutron number.

Journal Articles

Experimental verification of femtosecond laser ablation schemes by time-resolved soft X-ray reflective imaging

Tomita, Takuro*; Yamamoto, Minoru*; Hasegawa, Noboru; Terakawa, Kota*; Minami, Yasuo*; Nishikino, Masaharu; Ishino, Masahiko; Kaihori, Takeshi*; Ochi, Yoshihiro; Kawachi, Tetsuya; et al.

Optics Express (Internet), 20(28), p.29329 - 29337, 2012/12

 Times Cited Count:18 Percentile:65.08(Optics)

Pump and probe reflective imaging using a soft X-ray laser probe was applied to the observation of the early stage of femtosecond laser ablation process on platinum. In strongly excited area, drastic and fast reflectivity drop was observed. In moderately excited area, the decay of the reflectivity is slower than that in the strongly excited area, and the reflectivity reaches its minimum at t = 160 ps. In weakly excited area, laser-induced reflectivity change was not observed. These results give the critical information about the femtosecond laser ablation.

Journal Articles

Imaging of ablation dynamics by soft X-ray laser

Tomita, Takuro*; Hasegawa, Noboru; Nishikino, Masaharu; Kawachi, Tetsuya; Suemoto, Toru

Reza Kenkyu, 40(8), p.592 - 597, 2012/08

A single-shot soft X-ray laser pulse was used as a probe to investigate the early stage of the laser ablation process on platinum caused by the femtosecond near-infrared pump pulse. From time-resolved interferometry, we observed the dilation of the ablation front on a scale of 10 nm in the picosecond region. In the reflective imaging, we found three distinct types of dynamical responses, depending on the radial position in the pump beam spot. These characteristic behaviors correspond to different laser fluence and were attributed to different ablation schemes: spallation, homogeneous nucleation, and fragmentation/vaporization, which have been predicted from molecular dynamics simulation.

84 (Records 1-20 displayed on this page)