Chemical Journal of Chinese Universities-Chinese
The dense yittria-stabilized zirconia membrane tube was prepared by using pyridine as dispersant by vacuum casting. The thickness of the membrane in the tube is 0.2 mm and the length is 140 mm. The effect of sintering temperature on the density and ionic conductivity of the samples was studied. The solid oxide fuel cell(SOFC) was made of the YSZ membrane tube, which was sintered at 1 650 degreesC for 2 h. The electrochemical property of the SOFC was studied from 500 to 900 degreesC, hydrogen and city coal gas were used as fuel, respectively. The research shows that the YSZ membrane tube with a high quality and density can be prepared by the vacuum casting, the relative density of the YSZ membrane tube reaches 98.1% of theoretical density at sintering temperature of 1 600 degreesC, approaching the theoretical density. The maximum of open voltage is 1. 213 V, and the maximum of output power is 0. 48 W. The electrical property of the SOFC with hydrogen as fuel is superior to that of the one with city coal gas as fuel.
关键词:
vacuum casting;YSZ electrolyte membrane tubes;sintering properties;SOFC;yttria-stabilized zirconia;conductivity;technology;anode;sofc
Solid State Communications
The electronic and magnetic properties of the transition-metal compound MnSn were studied, using the full potential augmented plane wave plus local orbitals method within density functional theory. The total energy calculations show, amongst four investigated structures: zinc-blende, NaCl, CsCl, and NiAs, MnSn prefers the antiferromagnetic NiAs structure at the ground state. It was found that only the zinc-blende metastable phase is a half-metallic ferromagnet with a magnetic moment of 3.00(mu B) per formula unit, the ferromagnetic configuration is more stable than the antiferromagnetic one energetically. Its half-metallic gap reaches 0.24 eV at the equilibrium volume, and keep non-zero until compressed by 16% in the relative volume. The details of the electronic structure of zinc-blende MnSn were examined, the half-metalli city is attributed to the large exchange splitting and bonding-antibonding splitting. The volume compression results in the upward movement of the Fermi level, due to the increase in bandwidths, under the volume expansion an opposite behavior was found. (C) 2007 Elsevier Ltd. All fights reserved.
关键词:
magnetically ordered materials;electronic band structure;ground-state;temperature;alloys;stability;fe3o4;cro2;se;te;sb
K. Mii (Sumitomo Metal Industries
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Ltd.
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1-t-3 Otemachi
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Tokyo 100
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Japan)M Amano (National Research Institute for Metals
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1-2-1 Sengen
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Tsukuba 305
,
Japan)
金属学报(英文版)
The R & D of hydrogen absorbing alloys in Japan started in the early 1970s.Many alloys such as TiMm1.5 based alloys, Fe-Ti-O alloys (e.g. FeTi1.15 O0.024) andthe(mischmetal)Ni5 based alloys (e.g. MmNi4.5 Cr0.46 Mn0.04) were developed by the early 1980s. The application of these alloys to hydrogen storage, heat storage, heat pump, hydrogen purification and motor vehicles has been tried in many iaboratories,and the various techniques for using hydrogen absorbing alloys have been developed.The standarkization of evaluation methods for hydrogen absorbing alloys has been promoted by the Ministry of International Trade and Industry (MITI), and four of them were established as Japanese Industrial Standard (JIS).Alloys for Ni-Metal Hydride batteries have been extensively investigated since 1987in Japun. Mm-Ni-Co-Al-Mn alloys (e.g. MmNi3.55 Co0.75Al0.9Mn0.4) have been devel-oped and commereialized since 1990. The amount of production of small-size Ni-MH batteries in 1995 was about three hundred milliion in number and about one hundred billion yen. The R & D for higher enerpy-density Ni-MH batteries is intensively in progress.MITI and STA (Science and Technology Agency) have promoted the R & D of hydro-gen absorbing alloys in Japan by carrying out the national projects such as Sunshine Program (MITI: 1974-1993) and Utilization of Wind Engeray (STA 1980-1985). The New Sunshine Program (MITI 1993-2020) have started in 1993. This program con-tains the application of hydrogen absorbing alloys to Economical- Enerpy- City System and to We-NET (International Clean Energy System of Technology Utilizing Hydro-gen: World Energy Network.
关键词:
hydrogen absorbing alloy
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