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Composite Cathode Bi_(1.14)Sr_(0.43)O_(2.14)-Ag for Intermediate-temperature Solid Oxide Fuel Cells

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Journal of Wuhan university of technology(Materials Science) 2008年第3期23卷 350-353页

作者：高展张萍 Faculty of Material Science and Chemical Engineering China University of Geosciences

Composites consisting of strontium stabilized bismuth oxide （Bi1.14Sr0.43O2.14, SSB） and silver were investigated as cathodes for intermediate-temperature solid oxide fuel cells with doped ceria electrolyte. There were no chemical reactions between the two components. The microstructure of the interfaces between composite cathodes and Ce0.8Sm0.2O1.9 （SDC） electrolytes was examined by scanning electron microscopy （SEM）. Impedance spectroscopy measurements show that the performance of cathode fired at 700 ℃ is the best. When the content of Ag2O is 70 wt%, polarization resistance values for the SSB-Ag cathodes are as low as 0.2 Ωcm^2 at 700℃ and 0.29 Ωcm^2 at 650℃. These results are much smaller than some of other reported composite cathodes on doped ceria electrolyte and indicate that SSB-Ag composite is a potential cathode material for intermediate temperature SOFCs.

关键词： solid oxide fuel cells (SOFCs) composite cathode strontium stabilized bismuth oxide (SSB) samaria doped ceria (SDC)

Friction Properties of OTS SAMs and Silicon Surface under Water Lubrication

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Journal of Wuhan university of technology(Materials Science) 2009年第2期24卷 273-277页

作者：王馨 State Key Laboratory of Tribology Tsinghua University institute of nuclear and new energy technology Tsinghua University

The friction and wear properties of silicon surface covered with octadecyltrichlorosilane （OTS） self-assembled monolayers （SAMs） were investigated by a UMT-2 microtribometer with and without water as lubricant, and then compared with that of bare silicon surface. Dry friction measurement results show that OTS SAMs have a very low friction coefficient compared to bare silicon surface under lower sliding velocity and normal contact load. However, heavy wear occurs on OTS SAMs under higher contact stress and sliding velocity. Under water lubrication, OTS SAMs can prevent wear obviously and meanwhile present low coefficient of friction even under high velocities, The improved frictional and anti-wear property on OTS SAMs surface is attributed to the hydrophobic property of OTS and hydrodynamic effect of water. Furthermore, a wear critical phase diagram for OTS SAMs with and without water was proposed, which indicates that OTS SAMs working under water lubrication owns a wider range of available load and velocity to reduce friction and prevent wear.

关键词： silicon surface OTS SAMs water lubrication friction wear

Partitioning properties of rare earth ores in china

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Rare Metals 2005年第3期24卷 205-209页

作者： CHI Ru ＇an LI Zhongjun PENG Cui ZHU Guocai XU Shengming Hubei Key Laboratory of Chemical Reactor and Green Chemical technology Wuhan Institute of Chemical Technology Wuhan 430074 China institute of nuclear and new energy technology Tsinghua University Beijing 100084 China

The properties of rare earth partitioning in Chinese industrial rare earth ores were analyzed. Rare earth ores can be divided into the single-mineral type ore with bastnaesite, the multi-mineral type ore with bastnaesite and monazite, and the weathering crust type. Both the Bayan Obo rate earth ore and the Zhushan rate earth ore are a kind of mixed ore, consisting of basmaesite and monazite. Their rate earth partifionings are strongly enriched in light rate earths, where CeO2 is 50% and the light rate earth partitioning is totally over 95%. The Mianning rate earth ore as well as the Weishan rate earth is a kind of rate earth ore only having basmaesite. Their rare earth partitionings are also strongly enriched in light rate earths, in which CeO2 is 47% and the light rare earth partitioning is totally over 94%. For the weathering crust type rate earth ore, there are the Longnan rare earth ore, the Xunwu rare earth ore, and the middle yttrium and rich europium ore. In the Longnan rate earth ore, which is strongly enriched in heavy rate earths, Y2O3 is 64.83%, and the heavy and light rate earth partitionings are 89.40% and 10.53%, respectively. In the Xunwu rate earth ore, which is strongly enriched in light rate earths, CeO2 is 47.16%, and the light rate earth partitioning is totally 93.25%. Y and Eu are enriched in the middle yttrium and rich europium ore. Its middle rare earth partitioning is totally over 10%, and Eu2O3 and Y2O3 are over 0.5% and 20%, respectively, which are mainly industrial resources of the middle and the heavy rare earths.

关键词： rare earth ore partitioning bastnaesite monazite weathered crust ore

Preparation of High-Surface-Area SnO2 and ZrO2 by Reflux-Digestion and Solvothermal Methods

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稀有金属材料与工程 2006年第S3期 634-637页

作者： Ji-Ying Wei~1 Feng Jiang~1 Gang Xu~1 Sheng-Ming Xu~(1,2) (1.institute of nuclear and new energy technology,tsinghua university,beijing 100084,china) (2.State Key Laboratory of Chemo/Biosensing and Chemometrics,Hunan university,Changsha 410082,china)

The influence of the preparation methods on the properties of SnO2and ZrO2powders,especially the specific surface area and the stability upon calcination was ***2and ZrO2prepared by chemical precipitation using reflux-digestion process with NaOH possess high surface area at the calcination temperature of 500℃～1000℃.A novel solvothermal process in the presence of urea was used to synthesize nanocrystalline SnO2powders excluding the adulteration of *** increasing the concentration of urea,the grain size of the as-prepared powders reduced and the surface area increased. SnO2nanocrystals with a grain size of ca.1 nm and a high surface area of 331 m2g-1were obtained by this *** high-surface-area powders are favorable for gas-sensing and catalysis applications,and the development of an advanced material for structural engineering ceramics.

关键词： tin dioxide zirconia reflux-digestion solvothermal high-surface-area

On the Kernel-independent Fast Boundary Element Method for the 3-D Laplace Equation

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On the Kernel-independent Fast Boundary Element Method for t...

甜高粱茎秆固态发酵制取燃料乙醇过程分析与中试研究

第三届亚太国际工程中计算方法学术会议ICOME2009暨第九届全国工程中边界元、无网格等数值方法学术会议

作者： H. T. Wang 1*, Z. H. Yao 2 1 institute of nuclear and new energy technology, tsinghua university, beijing, 100084 china 2 Department of Engineering Mechanics, tsinghua university, beijing, 100084 china

A Kernel-independent fast multipole boundary element method (FMBEM) is developed for the numerical analysis of three-dimensional (3-D) Laplace equations. In this method, the conventional multipole moments of a collection of boundary elements inside a leaf box of the FMM tree are replaced by an equivalent density continuously distributed on a cubic surface enclosing the box. The far-field evaluations are achieved by the integration of potentials of the density. This equivalent density is discretised at the cubic surface and approximated by use of linear or quadratic boundary elements, and the calculation of its value is based on direct kernel evaluations. Therefore, the analytic expansions of the Laplacian kernels are avoided. Compared with the original fast multipole method first introduced by Greengard and Rokhlin in 1987 (J. Comput. Phys. 1987;73: 325-348), this kernel-independent method has the same data structures and performance procedures except that the equivalent densities are translated instead of both the multipole and local moments in the M2M, M2L and L2L translation operators. The translation matrices are precomputed, stored and repeatedly used at different tree levels. Several control parameters of this method are discussed briefly and their impact on the computational accuracies are tested. The computational efficiencies of this method are studied numerically and compared with several other algorithms including the conventional preconditioned GMRES solver, the original fast multipole boundary element method, the new version of the fast multipole boundary element method and other kernel-independent algorithms like the fully- and partially-pivoted adaptive cross approximation methods (ACA). The numerical results clearly show that the kernel-independent fast multipole boundary element method has O(N) complexity in both the computational time and data storage, and that for the requirement of engineering accuracy, this method has comparable computational ef

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来源： cnki会议评论

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太阳能学报 2010年第2期31卷 257-262页

作者：耿欣李天成李十中王二强中国农业大学资源与环境学院北京100193 清华大学核能与新能源研究院北京100084

研究了甜高粱秆固态发酵生产燃料乙醇过程工艺参数的变化规律及相关性,并以此为基础进行了5m^3转鼓式固态发酵反应器中试试验。结果表明:糖份的快速消耗伴随着乙醇的大量产生,酵母分泌相关酶类使非还原糖向还原糖转化;发酵过程pH下降,... 详细信息

研究了甜高粱秆固态发酵生产燃料乙醇过程工艺参数的变化规律及相关性,并以此为基础进行了5m^3转鼓式固态发酵反应器中试试验。结果表明:糖份的快速消耗伴随着乙醇的大量产生,酵母分泌相关酶类使非还原糖向还原糖转化;发酵过程pH下降,对乙醇产生无明显抑制;搅拌可以改善传质、传热,有利于菌体的生长和发酵的进行。中试结果表明40～44h内可完成发酵。直接固态发酵与蒸馏后获得30%～40%的粗醇溶液,平均13.5～15.5kg甜高粱秆产1kg(99.5%)无水乙醇,糟渣粗蛋白含量6.94%(干基),可替代"黄储"饲料。糖利用率最高97.50%,乙醇实际收率最高94.48%。

关键词：乙醇甜高粱秆固态发酵过程参数中试试验

Dark output characteristic of γ-ray irradiated CMOS digital image sensors

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Rare Metals 2002年第1期21卷 79-84页

作者： MENG Xiangti and KANG A iguo institute of nuclear energy technology, tsinghua university, beijing 100084, china institute of nuclear energy technology Tsinghua University 北京 100084

The quality of dark output images from the CMOS (complementarymetal oxide semiconductor) black and white (B & W) digital imagesensors captured before and after γ-ray irradiation was studied. Thecharacteristic parameters of the dark output images captured atdifferent radiation dose, e.g. average brightness and itsnon-uniformity of dark out- put images, were analyzed by our testsoftware. The primary explanation for the change of the parameterswith the radi- ation dose was given.

关键词： CMOS digital image sensor gamma radiation dark output characteristic Si

Simulating　Experimental　Investigation　on　the　Safety　of　nuclear　Heating　Reactor　in　Loss－of－Coolant　Accidents

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Journal of Thermal Science 1996年第4期5卷 285-291页

作者： Zhanjie Xu(institute of nuclear energy technology, tsinghua university, beijing, 100084, china) institute of nuclear energy technology Tsinghua University Beijing China

The 5MW low temperature nuclear heating reactor (NHR-5) is a new and advanced type of nuclear reactor developed by institute of nuclear energy technology (INET) of tsinghua university of china in 1989. Its main loop is a thermal-hydraulic system with natural circulation. This paper studies the safety of NHR under the condition of loss-of-coolant accidents (LOCAs) by means of simulant experiments. First, the background and necessity of the experiments are presented, then the experimental system, including the thermal-hydraulic system and the data collection system, and similarity criteria are introduced. UP to now, the discharge experiments with the residual heating power (20% rated heating power) have been carried out on the experimental system. The system parameters including circulation flow rate, system pressure, system temperature, void fraction, discharge mass and so on have been recorded and analyzed. Based on the results of the experiments, the conclusions are shown as folios: on the whole, the reactor is safe under the condition of LOCAs, but the thermal vacillations resulting from the vibration of the circulation flow rate are disadvantageous to the internal parts of the reactor core.

关键词： nuclear heating reactor natural circulation LOCA safety.

Kinetics study on the dissolution of UO_2 particles by microwave and conventional heating in 4 mol/L nitric acid

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Science china Chemistry 2008年第7期51卷 700-704页

作者： ZHAO YunFeng & CHEN Jing institute of nuclear and new energy technology, tsinghua university, beijing 102201, china institute of nuclear and new energy technology Tsinghua UniversityBeijing 102201China

The dissolution of UO2 particles in 4 mol·L-1 nitric acid medium at temperatures of 90-110℃ by mi- crowave heating and conventional heating has been investigated, respectively. It is found that the dissolution ratios of UO2 particles by microwave heating were 10%-40% higher than that by conven- tional heating. Kinetics research shows that the dissolution of UO2 particles in 4 mol·L-1 nitric acid is controlled by the diffusion control model for microwave heating and by the surface reaction control model for conventional heating. The diffusion control model for the dissolution of UO2 particles by mi- crowave heating could be explained by the diffuseness on the surface of UO2 particles.

关键词： uranium dioxide nitric acid dissolution microwave heating