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Mathematical Model for the Drying process of Granular Materials in a Fluidized Bed

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International Journal of Minerals,Metallurgy and Materials 2000年第4期14卷 296-300页

作者： Xiulan Huai, Li Wang, Zhiyun Qu ( Mechanical Engineering school, University of Science and technology beijing, beijing 100083, china Chemical Industry research institute of Shanxi, Taiyuan 030031, china) Mechanical Engineering school University of Science and Technology Beijing Beijing 100083 China Chemical Industry research institute of Shanxi Taiyuan 030031 China

The experiment of granular materials, barley, drying in a fluidized bed was carried out to investigate the influence of the factors, inlet air temperature, air moisture, bed height and original moisture content of the dried materials on drying process. Based on the experimental data, a corresponding mathematical model is presented. As a conclusion, a higher inlet air temperature and a reasonable bed height should be used so as to increase the dring rate and to improve the product quality.

关键词： fluidization granular materials drying, experimental investigation mathematical model Information

Calculating soil moisture by remote sensing and analyzing hydrologic cycle process in the Yellow river basin

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Science china(Technological Sciences) 2004年第z1期47卷 1-13页

作者： YANG Shengtian1 & LIU Changming1, 2 1. school of Environmental Sciences, beijing Normal University, beijing 100875, china 2. institute of Geographic Science and Natural resources research, beijing 100101, china beijing Normal Univ Sch Environm Sci Beijing 100875 Peoples R China Inst Geog Sci & Nat resources Beijing 100101 Peoples R China

Based on the AVHrr pathfinder remote sensing data, soil moisture, precipitation and evaporation during the period of 1982—1998, soil moisture of all layers of soil-profile (0—1 m) in the Yellow river basin over the 17 years are calculated by the remote sensing model of calculating soil water. The Yellow river basin is divided into seven subcatchments as control sections at the location of six hydrologic stations (Lanzhou, Toudaoguai, Longmen, Sanmenxia, Huayuankou and Lijin). After calculating soil moisture and obtaining runoff data and precipitation data, the dynamical features of hydrological cycle in the Yellow river basin are analyzed for the period from 1982 to 1988 using water balance method. The conclusions are as follows: It is feasible to calculate the soil water on the macro-scale, in the soil profile with temporal continuity by means of remote sensing and survey in land. Some values of the key water cycle factors in the Yellow river are obtained, which include the annual precipitation of 4000 km3, the evapotranspiration of 3000-3500 km3, and the soil moisture transformation of ?500- 500 km3. Consequently, we analyzed the process of the water cycle in the Yellow river over the 17 years, and the results show that the segment upstream of Lanzhou city is a relatively humid region, and the area of internal waters and the reaches of Shanshan is the most desiccated region. Therefore, the runoff in the depth process is intensive and the runoff-generating process is weak in more arid regions.

关键词： the Yellow river, soil moisture, remote sensing, hydrologic cycle.

In-plane bistatic backward scattering from seabottom with randomly inhomogeneous sediment and rough interface

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Science china(physics,Mechanics & Astronomy) 2004年第6期47卷 702-716页

作者： pENG Zhaohui1,,ZHOU Jixun1,& ZHANG renhe1 2 2 1.institute of Acoustics,Chinese Academy of Sciences,beijing 100080,china 2.school of Mechanical Engineering,Georgia institute of technology,Atlanta,GA 30332,USA 1. institute of Acoustics Chinese Academy of Sciences 100080 Beijing China 2. school of Mechanical Engineering Georgia Institute of Technology 30332 Atlanta GA USA

The in-plane bistatic backward scattering caused by seabottom with random inhomogeneities and rough interface is studied. This work combines the ray tube integral method of Ivakin et al. and the complex-ray/steepest descent method of Hines. For a given incident grazing angle, the theoretical expression can easily be used to calculate scattering strength for different backward scattering angles. (This is essential for modeling shallow water reverberation by the normal mode approach.) The model is tested against published scattering measurements. The frequency/angle dependence of backward scattering and effects of volume inhomogeneity parameters on backward scattering are also discussed.

关键词： in-plane bistatic backward scattering, inhomogeneous sediment, rough interface.

Modified HDDr process for producing Anisotropic NdFeB powders

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Journal of University of Science and technology beijing 2001年第2期8卷 111-114页

作者： Xubo Liu, Yue Ming, Yaofu Xiao, Qi Zeng, Zhengyi Zhang, run Wang (Material Science and Engineering school, University of Science and technology beijing, beijing 100083, china) (beijing institute of Aeronautical Materials, beijing 100095, china) Univ Sci & Technol beijing Mat Sci & Engn Sch Beijing 100083 Peoples R China Inst Aeronaut Mat Beijing 100095 Peoples R China

The effect of HDDr (hydrogenation-decomposition-desorption-recombination process) treating conditions on magnetic anisotropy of Nd13FebalCo17B7Ga1Zr0.1 powders has been studied. It is found that increasing recombination temperature is effective for magnetic anisotropy formation, but at the cost of reducing the coercive force. The microstructure analysis (TEM) indicates that the NdFeB recombination nucleation takes place markedly during the transition range from decomposition stage to recombination stage, in which both temperature and H-2 pressure change sharply. In order to create a more stable treatment condition for recombination nucleation, a modified HDDr process is established in which the conventional continuous transition range is divided into several stages. The experimental results have proved that such a process can effectively enhance the remanence of the magnet powders with high certainty, while only cause a little reduction in coercivity.

关键词： HDDr anisotropy NdFeB

High-sensitivity photovoltage based on the interfacial photoelectric effect in the SrTiO_(3-δ)/Si heterojunction

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Science china(physics,Mechanics & Astronomy) 2010年第11期53卷 2080-2083页

作者： WEN Juan 1,GUO HaiZhong 1,XING Jie 2,Lü HuiBin 1,JIN Kui-Juan 1,HE Meng 1 & YANG GuoZhen 1 1 beijing National Laboratory for Condensed Matter physics,institute of physics,Chinese Academy of Sciences,beijing 100190,china 2.school of Materials Sciences and technology,china University of Geosciences,beijing 100083,china 1. beijing National Laboratory for Condensed Matter physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China2. School of Materials Sciences and Technology China University of Geosciences Beijing 100083 China

A high sensitivity photovoltaic effect has been observed in a heterojunction composed of n-type wide bandgap oxide SrTiO 3-δ and p-type Si fabricated by laser molecular beam *** responsivity of open-circuit photovoltage can reach 10 4 V/W without any amplification under zero bias for the wavelength range from visible to near infrared light in nW-μW *** attribute the high performance of the photovoltage responsivity to the interfacial photoelectric effects in the SrTiO 3-δ /Si *** the experimental results,some ideas can be generalized to improve photovoltaic efficiency and develop high sensitivity photodetectors with wide bandgap oxide materials and Si.

关键词： SrTiO 3-δ/Si heterojunction interfacial photoelectric effect photovoltage

ASYMpTOTICALLY　EFFICIENT　ESTIMATES　IN　A　SYSTEM　TrEE

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Systems Science and Mathematical Sciences 1996年第2期9卷 157-163页

作者： DAI Ming(Department of Applied Mathematics beijing institute of technology, beijing, 100081, china) 北京理工大学应用数学系北京

ＡＳＹＭＰＴＯＴＩＣＡＬＬＹＥＦＦＩＣＩＥＮＴＥＳＴＩＭＡＴＥＳＩＮＡＳＹＳＴＥＭＴＲＥＥＤＡＩＭｉｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＡｐｐｌｉｅｄＭａｔｈｅｍａｔｉｃｓＢｅｉｊｉｎｇｉｎｓｔｉｔｕｔｅｏｆＴｅｃｈｎｏｌ... 详细信息

ＡＳＹＭＰＴＯＴＩＣＡＬＬＹＥＦＦＩＣＩＥＮＴＥＳＴＩＭＡＴＥＳＩＮＡＳＹＳＴＥＭＴＲＥＥＤＡＩＭｉｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＡｐｐｌｉｅｄＭａｔｈｅｍａｔｉｃｓＢｅｉｊｉｎｇｉｎｓｔｉｔｕｔｅｏｆＴｅｃｈｎｏｌｏｇｙ，Ｂｅｉｊｉｎｇ，１０００８...

关键词： Virtual system method (VS Method) system tree subsystem tree, asymptotically efficient.

possibility of reducing Formations of NO_x and SO_2 Simultaneously during Coal Combustion

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International Journal of Minerals,Metallurgy and Materials 2000年第3期14卷 165-169页

作者： Chunbao Xu, Shengli Wu, Daqiang Cang ( Metallurgy school, University of Science and technology beijing, beijing 100083, china institute for Chemical reaction Science, Tohoku University, Japan) Metallurgy school University of Science and Technology Beijing Beijing 100083 China institute for Chemical reaction Science Tohoku University Japan

Comparing with other NO_x and SO_2 control technologies, in-bed reducing NO_x and SO_2 simultaneously during coal combustion may lower the investment and operation cost. However, there are several possible contradictions between the reduction of NO_x and the capture of SO2 during combustion: 1) CO rich atmosphere is favorable for the reduction of NO_x, whereas O_2 rich favorable for the capture of SO_2; 2) higher preheating temperature of coal is favorable for reducing NO_x, but unfavorable for reducing SO_2; 3) sulphation of some minerals may deactivate their catalytic effect on the reduction of NO_x. The attempts to eliminate such contradictions by coating coal granules with thin layer of monometallic oxides and mixed oxides were proposed. Ni_2O_3 and Fe_2O_3 showed high activity on NOx reduction and CaO and Cr_2O_3 showed good effect on sulfur capture. The mixed metallic oxides, e.g., Fe_2O_3NiO, etc., showed effective for both NO_x reduction and SO_2 retention. It is possible to in-bed reduce NO_x and SO_2 simultaneously if the adhering materials are properly chosen to be difunctional materials of both active catalysts for NO_x reduction reactions and better sorbents for SO_2 retention.

关键词： coal combustion purification of NO and SO catalyst sorbent

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液力变矩器泵轮叶片优化设计研究

系统仿真学报 2008年第23期20卷 6549-6552,6556页

作者：魏巍闫清东北京理工大学机械与车辆工程学院北京100081 北京理工大学车辆传动国家重点实验室北京100081

提出一种液力变矩器叶栅系统的优化设计方法,通过含有参数化设计与流场数值模拟环节的正交试验设计样本构建目标的响应曲面(rSM)近似模型,再由序列二次规划法(SQp)反复迭代并更新模型逼近最优解。结果表明该方法在工程设计上是有效的,... 详细信息

提出一种液力变矩器叶栅系统的优化设计方法,通过含有参数化设计与流场数值模拟环节的正交试验设计样本构建目标的响应曲面(rSM)近似模型,再由序列二次规划法(SQp)反复迭代并更新模型逼近最优解。结果表明该方法在工程设计上是有效的,并且证实了加大泵轮叶片内环出口角的扭曲角度可以有效地提高变矩器的变矩性能,但起动变矩比增大的同时最高传动效率会有所下降。

关键词：液力变矩器优化设计叶片试验设计响应曲面

The influence of defects on the effective Young's modulus of a defective solid

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Chinese physics B 2013年第4期22卷 307-311页

作者：沈伟范群波王富耻马壮 Central Iron and Steel research institute school of Materials Science and Engineering Beijing Institute of Technology

It is difficult to establish structure-property relationships in a defective solid because of its inhomogeneous-geometry microstructure caused by defects. In the present research, the effects of pores and cracks on the Young’s modulus of a defective solid are studied. Based on the law of the conservation of energy, mathematical formulations are proposed to indicate how the shape, size, and distribution of defects affect the effective Young’s modulus. In this approach, detailed equations are illustrated to represent the shape and size of defects on the effective Young’s modulus. Different from the results obtained from the traditional empirical analyses, mixture law or statistical method, for the first time, our results from the finite element method （FEM） and strict analytical calculation show that the influence of pore radius and crack length on the effective Young’s modulus can be quantified. It is found that the longest crack in a typical microstructure of ceramic coating dominates the contribution of the effective Young’s modulus in the vertical direction of the crack.

关键词： defects effective Young’s modulus conservation of energy pore radius and crack length