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61.
62.
Oxygen potentials of oxide nuclear fuels are important thermodynamic data in development of nuclear fuel technologies. Minor actinide bearing MOX (mixed oxide) fuels have been developed as sodium cooled fast reactor fuels. Content of Am which is one of the minor actinide elements causes oxygen potentialto increase. The effects of the oxygen potential increase on the irradiation behavior were evaluated. Profiles of temperature and O/M (oxygen-to-metal) ratio in the pellets were evaluated to better understand the irradiation behavior. From these data, local oxygen potential in the radial direction of the pellets was calculated, and was compared with free energy of compounds composed of fission products. Based on this comparison, it was concluded that Cs2MoO4 was likely formed at pellet periphery of (U07Pu03)O1.98 and (U0.66Pu03Amoo16Npo.016)Ol.976 The extent of cladding tube inner surface oxidation was predicted by using the calculated oxygen potential. No significant difference between irradiation behaviors of (Uo.7Puo3)O2_x and (U0.66PUo 3Amo.016Npo.016)O2.x pellets was confirmed. 相似文献
63.
Atsushi Takada Yu-Ichi Komizo Hidenori Terasaki Tomoyuki Yokota Kenji Oi Koichi Yasuda 《Welding International》2013,27(4):254-261
Inclusions contributing to acicular ferrite nucleation were investigated from a crystallographic point of view in low carbon low alloy steelweld metals. The samples from electro slag welding (ESW) and submerged arc welding (SAW) deposits with various cooling rates were prepared in this study. In those samples, intragranular acicular ferrite formation was observed from inclusions. The inclusions contributing to acicular ferrite formation were of multi-phase type consisting of amorphous phase, spinel type and MnS. They were surrounded by a Ti-enriched layer. It was confirmed by selected area diffraction patterns and energy-dispersive X-ray spectrometer analyses that the Ti-enriched layer was TiO. The acicular ferrite had a Baker–Nutting orientation relationship with the TiO layer on the inclusion surface. The misfit was 3.0% at the interface between the acicular ferrite and TiO. Therefore, it is considered that TiO on the inclusion surface contributes to the heterogeneous nucleation of acicular ferrite by small lattice misfit. However, themorphologies of ferrite growth which nucleated from inclusions were different in both samples. Whereas the growth of ferrites nucleated from TiO was enough in ESW, the size of nucleated ferrite in SAW was a few hundred millimetres in size. In the early stage of nucleation from TiO, ferrite had small deviation from Kurdjumov–Sachs orientation relationship (K–S relationship) in both ESW and SAW. However, there was a difference in the growth stage of ferrite. The ferrite orientations were gradually changed to fit to the K–S relationship in ESW. On the other hand, the nucleated ferrite in SAW stopped growing and the newly nucleated ferrite which had K–S relationship prior to austenite was formed adjacently because of large super cooling due to small heat input. 相似文献
64.
Synthesis of ethanol by hydrogenation of carbon dioxide has been investigated by developing the novel composite catalysts. The three different kinds of elementary reaction functions for ethanol synthesis were undertaken. The catalytic functions are partial reduction of CO2 to CO, C–C bond formation, and –OH group insertion. For this purpose, supported Rh catalyst, Fe-based modified Fisher–Tropsch catalyst, and Cu-based modified methanol synthesis catalyst were combined by different ways. As a result, high space–time yields of ethanol as high as 0.8–0.9 kg/l h were obtained. 相似文献
65.
Haruhiko Morito Tomoyuki Ide Taiki Karahashi Hironori Orikasa Takahiro Yamada Hisanori Yamane 《Journal of the American Ceramic Society》2009,92(11):2578-2582
A bulk layer of aluminum nitride (AlN) polycrystals was synthesized on a boron nitride crucible surface by heating Al chunks with 5 mol% of bismuth at 1273 K for 3 h under NH3 gas flow. The fragments of the layer were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The platelet grains of AlN with a size of 0.1–1.0 μm and having preferred orientation of the c -axis perpendicular to the layer were formed at the crucible side. Nanotubes 6–15 μm long and about 20–100 nm thick grew on the gas phase side of the layer. 相似文献
66.
The pitch control of wind generators is usually made by a feed back control concept. However, under the conditions where a wind speed changes very frequently due to geographic reasons of the site and the target system has large rotor inertia, the feed back signal which is applied to the control system to compensate disturbance such as wind speed variations is delayed, and consequently the control strategy to keep the generated power at a constant value does not work well. If the wind speed shows too much variation, this will cause a violent variation of power and result in step out operation of the generator from the power system due to magnetic saturation. This paper proposes a control strategy to reduce the power variations by introducing feed forward control combining with the conventional feed back control. 相似文献
67.
68.
The flashover voltage with a backside electrode was found to be lower than that without the backside electrode. Under microsecond pulse voltage application, we describe the characteristics of a creeping discharge developed in the narrow gap with the backside electrode. Using a CCD camera and ultrahigh‐speed camera, we observed the corona extension processes. The lowest flashover voltage was found to be obtained at positive polarity with a SF6 content D = 3%. In the corona extension obtained using an ultrahigh‐speed camera, peculiar differences were observed in the corona extension process. The corona extension increased, and rapid flashover was observed at D = 3%. Using a CCD camera, small coronas were detected from the backside electrode. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 158(2): 31–38, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20431 相似文献
69.
Tomoyuki Kitano Takayuki Wani Toshiyuki Ohnishi Jiang Li-Fen Yasushi Kuroda Atsutaka Kunai Kazuo Sasaki 《Catalysis Letters》1991,11(1):11-18
Catalytic oxidation of benzene in the gas phase has been studied as a function of the catalyst composition, reaction temperature and the feed conditions of reactant gases, hydrogen, oxygen, benzene as well as diluting inert gas. The catalyst tested is composed of Pd and Cu(I) ions, both of which are supported on silica gel. If one of the two metal species is lacked from the catalyst, no catalytic activity appears. The product is almost exclusively phenol and some accompanying benzoquinone, in particular at lower temperatures, as minor byproduct.On leave from Hua-Dong Institute of Technology, Nanjing, People's Republic of China. 相似文献
70.
Tomoyuki Kawaguchi Yasuhiro Rachi Wataru Sugimoto Yasushi Murakami Yoshio Takasu 《Journal of Applied Electrochemistry》2006,36(10):1117-1125
Highly dispersed ternary PtRuRh/C anode catalysts for direct methanol fuel cells were prepared with various contents and their electro-catalytic activities towards methanol oxidation at 25 °C and 60 °C were examined to investigate the influence of the catalyst composition. Electrocatalysts were prepared by a co-impregnation method using ethanolic solutions of metal precursors and carbon black followed by pyrolysis under reducing conditions. X-ray diffraction analysis revealed that the fcc peaks shifted to higher diffraction angles with increasing Rh content, indicating the alloying of Rh into the fcc structure. In terms of the mass specific current density, the activity towards methanol oxidation differed significantly depending on the catalysts composition and cell temperature. The catalyst prepared at a ratio of Pt:Ru:Rh = 1:1:2 exhibited the highest activity at 60 °C of 155 A (g-Pt)−1 at 0.5 V vs. RHE. 相似文献