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Transport Properties of LCMO Granular Films Deposited by the Pulsed Electron Deposition Technique

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Journal of Wuhan university of Technology(Materials Science) 2011年第6期26卷 1027-1031页

作者：陈雷明 Zhengzhou Institute of Aeronautical Industry Management

By finely controlling the deposition parameters in the pulsed electron deposition process, granular La 2.3 Ca 1/3 MnO 3 （LCMO） film was grown on silicon substrates. The substrate temperature, ambient pressure in the deposition chamber and acceleration potential for the electron beam were all found to affect the grain size of the film, resulting in different morphologies of the samples. Transport properties of the obtained granular films, especially the magnetoresistance （MR）, were studied. Prominent low-field MR was observed in all samples, indicating the forming of grain boundaries in the sample. The low-field MR show great sensitive to the morphology evolution, which reaches the highest value of about 40% for the sample with the grain size of about 2.0 nm. More interestingly, positive-MR （p-MR） was also detected above 300 K when low magnetic field applying, whereas it disappeared with higher magnetic field applied up to 1.5 and 2.Tesla. Instead of the spin- polarized tunneling process being commonly regarded as a responsible reason, lattice mismatch between LCMO film and silicon substrate appears to be the origin of the p-MR

关键词： colossal magnetoresistance granular film transport properties

Combustion synthesis of radioactive waste immobilization

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Rare Metals 2005年第2期24卷 119-124页

作者： ZHANGRuizhu GUOZhimeng LUXin JIAChengchang LINTao MaterialsScienceandEngineeringSchool UniversityofScienceandTechnologyBeijingBeijing100083China MaterialsScienceandEngineeringSchool UniversityofScienceandTechnologyBeijingBeijing100083China／／NorthChinaInstituteofWaterConservancyandHydroelectricPowerZhengzhou450011China

Using chromium oxide (CrO3) as an oxidant, the immobilization of simulating radioactive waste in perovskite (CaTiO3) structure by a combustion synthesis (CS) method was tested. The products were characterized by Archimedes liquid displacement technique, microhardness technique, X-ray diffraction, and scanning electron microscopy. The leaching rate was measured by the method of MCC-1 or MCC-2. The primary results show that the CS method can be used to solidify the immobilizate waste effectively.

关键词： combustion synthesis radioactive waste Immobilization perovskite

NUMERICAL MODELING PURIFICATION PERFORMANCE OF POT TEST

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Journal of Hydrodynamics 2010年第5期22卷 709-718页

作者： DAI Yu WANG De-guan ZHANG Jin-feng LUAN Qing-hua Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education Hohai University Nanjing 210098 China College of Mechanics and Materials Science Hohai University Nanjing 210098 China College of Environmental Hohai University Nanjing 210098 China College of Water conservancy and {2. Hebei University of Engineering Handan 056021 China

A three-dimensional mathematical model was developed to simulate the pollutant removal efficiency of the soil and plants in the pot test. The advection, dispersion, diffusion, adsorption, biochemical reaction and plant uptake processes were taken into account in the model. The three-dimensional modified Richards equation was used in simulating flow field. The mass balance law was employed in deriving the equation for pollutant transport, where the diffusion and dispersion were described with the Fick-type law, the adsorption was macroscopically expressed as form isotherm, and the bio-chemical degradation process was assumed to follow the Monod kinetics. The mathematical model was descretized by the finite element numerical method. In the pot test, the hydraulic loading was assumed to have the intermittent pattern simulating the rainfall duration and the occurrence of frequency, and the concentrations of pollutants in the influent and effluent were measured. The computed overall removal rates for the CODCr and TN in four cases are in the range of 90.62. - 95.43% and 85.01% - 96.46%, respectively. The differences between the computed and tested overall removal rates for the CODCr and TN are smaller than 5%. The time-varying oscillation pattern of the concentrations of the CODCr and TN were rationally simulated, which showed that the model presented in this article could be used to assess the pollutant removal efficiency of the soil and plants in related cases.

关键词： pot test numerical modelling pollutant removal efficiency experiments

INFLUENCE OF FILLING WATER ON AIR CONCENTRATION

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Journal of Hydrodynamics 2011年第5期23卷 601-606页

作者： WU Jian-hua MA Fei DAI Hui-chao College of Water conservancy and {2. Engineering Hohai University Nanjing 210098 China

The filling water inside the cavity below an aerator occurs for the flow of low Froude number or the small bottom slope of a spillway. The aerator may cease to protect against cavitation damages, and may even act as a generator of cavitation if it is fully filled by water. The experiments were conducted to investigate the influences of the geometric parameters, and then the filling water on the air concentration. The results show that the filling water, or the net cavity length, is closely related to the plunging jet length for a given aerator, and the air concentration at some section is proportional to the ratio Ln/Lj at a fixed Lj for different geometric parameters of aerators. Secondly, at the same ratio of Ln / Lj, the aerator with a larger height or a larger angle of ramp, or a larger bottom slope, would have a larger plunging jet length, and then a larger net cavity length based on the ratio of Ln / Lj. As a result, the large space of cavity, or the high air concentration of the flow could be obtained although the filling water increases also based on the fact that Lf = Lj - Ln. It is the space of the cavity that is the dominant factor to affect the air concentration of the flow.

关键词： aerator air concentration filling water jet length net cavity length

Fuzzy Approach to Determining Priority Preorders of Water Resources Projects

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Transactions of Tianjin university 2009年第2期15卷 121-125页

作者：刘英杰冯平 School of Civil Engineering Tianjin University Civil Engineering Supervisor Center North China Institute of Water Conservancy and Hydroelectric Power

In this paper,the criteria set related to the priority preorders of water resources projects is introduced.A fuzzy multiple criteria group decision-making model is established,which incorporates quantitative analysis,judgments,experience and preferences of *** model is used in practice to determine the priority preorders of five water resources projects,and the results show that the best choice can supply more new employment,domestic water and irrigation water,and has better quality.

关键词： fuzzy decision-making priority preorders water resources projects

A MATHEMATICAL MODEL OF MIGRATION AND EXPANSION OF MEANDER LOOPS

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Journal of Hydrodynamics 2010年第2期22卷 214-220页

作者： DAI Wen-hong TANG Hong-wu State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering College of Water Conservancyand Hydropower Engineering Hohai University Nanjing 210098 China

This article presents a mathematical model of the plane evolution of alluvial meandering streams,through downstream migration and lateral expansion of meander *** the conditions prevailing in natural streams,the channel centerlines follow sine-generated curves,with an assumed steady-state turbulent and subcritical flow,of large width-to-depth ratio（≥ 15,for example） and small Froude number（Fr ）.The plane deformation of the channel is caused by the action on the banks of the convective vertically-averaged meandering *** growth（migration and expansion） of meander loops is attributed to the *** computational results of the model show that the obtained migration and expansion patterns of the meander loops are in good agreement with those of observations and measurements in similar meandering streams.

关键词： mathematical model downstream migration lateral expansion meander loop vertically-averaged flow bank deformation measurements

Comprehensive benefit of flood resources utilization through dynamic successive fuzzy evaluation model: A case study

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中国科学：技术科学英文版 2010年第2期53卷 529-538页

作者： FENG Feng1,2. XU ShiGuo1, LIU JianWei1, LIU Dan1,3 & WU Bo4 1 Institute of Water Environment, School of Civil and Hydraulic Engineering, Dalian university of Technology, Dalian 11602., china 2.Yellow River {2. Technical Institute, Kaifeng 475003, china 3 College of Water Resources, Shenyang Agricultural university, Shenyang 110161, china 4 Office of Flood Control and Draught Relief in Jilin Province, Changchun 130033, china Institute of Water Environment School of Civil and Hydraulic Engineering Dalian University of Technology Dalian China Yellow River conservancy Technical Institute Kaifeng China College of Water Resources Shenyang Agricultural University Shenyang China Office of Flood Control and Draught Relief in Jilin Province Changchun China

Taking the flood resources utilization in Baicheng, Jilin during 2.02.2.07 as the research background, and based on the entropy weight and multi-level & multi-objective fuzzy optimization theory, this research established a multi-level & semi-constructive index system and dynamic successive evaluation model for comprehensive benefit evaluation of regional flood resources utilization. With the year 2.02.as the base year, the analyzing results showed that there existed a close positive correlation between flood utilization volume and its benefits, comprehensive evaluation value and its comparison increment. Within the six successive evaluation years, the comprehensive benefit of 2.03 was the best, in which the benefit evaluation increment reached 82.8% whereas the year of 2.04 was the worst, in which the increment was only 18.2.. Thus the sustainability and correctness of the evaluation were verified by six years successive evaluation and increment comparison. The analyzing results showed that the economic benefits, ecological benefits and social benefits of flood utilization were remarkable, and that the comprehensive benefit could be improved by increasing flood utilization capacity, which would promote the regional sustainable development as well. The established dynamic successive evaluation provides a stable theoretical basis and technical support for further flood utilization.

关键词： flood resources utilization comprehensive benefit dynamic successive fuzzy evaluation Baicheng City

Porous Media Percolation Research Based on the Ideal Model

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Porous Media Percolation Research Based on the Ideal Model

THE ROLE FORE AIR FLOW IN SOIL SLOPE STABILITY ANALYSIS

第十届全国渗流力学学术会议暨2.09渗流力学及应用国际论坛

作者： YU Keguang~1,ZHOU Hangxia~2.ZHENG Peng~2.1 Zhejiang Water conservancy And hydropower C{2.,Hangzhou,310018,china, 2.china Jiliang university,Hangzhou,310018,china

The model of percolation Base on a ideal ball,Research the relationship between fluid’s penetration ratio and porous media of different particle *** the relation model of particle radius and penetration ratio by theoretical *** the change rule between the penetration ratio and particle *** foundation theoretical data for mixing ratio of different particle radius. Lay the foundation for the further research about computing synthesis percolation ratio of mixing ratio of groups porous media of different particle radius.

关键词： particle radius flow model penetration ratio

来源： cnki会议评论

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Journal of Hydrodynamics 2009年第5期21卷 640-646页

作者： ZHANG Xiao-yue ZHU Yue-ming FANG Chun-hui College of Water conservancy and {2. Engineering Hohai University Nanjing 210098 China

In order to investigate the effect of the pore air flow in the soil slope stability analysis, a water-air two-phase flow model, based on the multi-phase flow theory, is proposed and with the model, the water-phase and air-phase seepages of the soil slope in the stable seepage and rainfall situations are simulated. The soil slope safety coefficients are obtained according to the simulated pore air pressure and pore water pressure. The calculation results show that in the stable seepage situation, the influence of the pore air pressure on the soil slope stability can be neglected, while in the rainfall situation, the pore air pressure generated in the unsaturated zone will reduce the safety coefficient, and the larger the distance between the slip surface and the underground water level is, the greater the influence of the pore air pressure on the soil slope stability will be.

关键词： unsaturated soil water-air two-phase flow rainfall slope stability