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Regulation mechanism of EM parameters in natural ferrite and its application in microwave absorbing materials

Science china(Technological Sciences) 2006年第1期49卷 38-49页

作者： ZHENG Yongchun1,2, WANG Shijie2, FENG Junming2, LI Chunlai1, OUYANG Ziyuan1,2, LIU Jianzhong1 & LI Xiaobiao2 1. national Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, china 2. State key laboratory of environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, china 1. national Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China 2. State key laboratory of environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

electromagnetic (EM) parameters (ε ′, ε ″, μ ′, μ″ ) of several M2+Fe2O4 and Fe2O3 type natural ferrites with different geological occurrences are measured in this pa-per. The measurement results show that EM parameters of a magmatic-occurring natural ferrite is very different from other types occurring from sedimentary-metamorphic iron deposit, hydrothermal vein iron deposit, outer contact of magmatic iron deposit. It has potential to be used as magnetic absorbent in microwave absorbing materials. After min-eral separation and concentration, this magmatic-occurring natural ferrite was processed into type A ferrite absorbent. Type A natural ferrite absorbent is a kind of magnetic material with low dielectric constants, high magnetic conductivity and high EM loss. Its EM pa-rameters are ε ′ = 58.60, ε ″ = 10.0, μ ′ = 1.2-1.5, μ ″ = 1.0-1.2, respectively. In order to illuminate the regulation mechanism of EM parameters, we studied the chemical and mineral composition of type A ferrite absorbent. There is high concentration of natural impurities, which regulate the EM parameters of type A ferrite greatly. For comparison, the other types of natural ferrite, single-phase magnetite and two-phase iron minerals (ilmen-ite and magnetite), have few impurity. Thus regulation mechanism of EM parameters was absent in these ferrites. As a result, the regulation of EM parameters is advantageous to develop type A natural ferrite as excellent absorbent, lowers the reflectivity coefficients and enhances the absorbing efficiency of MAM made from it. Furthermore, the impurities in type A natural ferrite and its effects on EM parameters are very difficult to simulate in the synthesize ferrite. The carbonyl-iron powder is another kind of absorbent that is used ex-tensively in MAM. To compare the absorbing properties of these two absorbent, type A natural ferrite and carbonyl-iron powder were mixed with rubber and processed into mi-crowave absorbing sheets with the same procedures and tec

关键词： natural impure ferrite, complex permittivity, complex permeability, microwave absorbing materials.

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H5N1 avian influenza in china

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Science china(Life Sciences) 2009年第5期52卷 419-427页

作者： CHEN HuaLan Animal Influenza laboratory of the Ministry of Agriculture and national key laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, china Animal Influenza laboratory of the Ministry of Agriculture and national key laboratory of Veterinary Biotechnology Harbin Veterinary Research Institute Chinese Academy of Agricultural Sciences Harbin 150001 China

H5N1 highly pathogenic avian influenza virus was first detected in a goose in Guangdong Province of china in 1996. Multiple genotypes of H5N1 viruses have been identified from apparently healthy waterfowl since 1999. In the years 2004-2008, over 100 outbreaks in domestic poultry occurred in 23 provinces and caused severe economic damage to the poultry industry in china. Beginning from 2004, a culling plus vaccination strategy has been implemented for the control of epidemics. Since then, over 35420000 poultry have been depopulated, and over 55 billion doses of the different vaccines have been used to control the outbreaks. Although it is logistically impossible to vaccinate every single bird in china due to the large poultry population and the complicated rearing styles, there is no doubt that the increased vaccination coverage has resulted in decreased disease epidemic and environmental virus loading. The experience in china suggests that vaccination has played an important role in the protection of poultry from H5N1 virus infection, the reduction of virus load in the environment, and the prevention of H5N1 virus transmission from poultry to humans.

关键词： avian influenza H5N1 control china

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Numerical study of sea waves created by tropical cyclone Jelawat

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Acta Oceanologica Sinica 2011年第5期30卷 64-70页

作者： LI Jie QIAN Hongbao LI hai LIU Yu GAO Zhiyi key laboratory of Research on Marine Hazards Forecasting National Marine Environment Forecast Center State Oceanic Administration Beijing 100081 China Administrative Center for china＇s Agenda 21 Beijing 100038 China

A numerical study of sea waves generated by tropical cyclone Jelawat is carried out using the cycle 4 version of the *** model domain currently covers the latitudes 20-45 N and longitudes 115-135 E,and the model spatial resolution reaches 0.25 ×*** of the model results with buoy observations reveals that the model can fairly reproduce the temporal variation of observed ***-dimensional comparison is also made against the satellite altimeter significant wave heights derived from TOPEX/POSEIDON and ERS-2 data,showing high quality of the model performance.

关键词： wave model tropical cyclone Jelawat simulation altimeter wave height

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A heuristic algorithm for cube packing with time schedule

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Science china(Information Sciences) 2010年第1期53卷 18-29页

作者： LI Wei1, HUANG WenQi2, JIANG DongChen1 & LIU XiangLong1 1State key laboratory of Software Development environment, Beihang University, Beijing 100191, china 2School of Computer Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, china 1. State key laboratory of Software Development environment Beihang University Beijing 100191 China2. School of Computer Science and Technology Huazhong University of Science and Technology Wuhan 430074 China

Packing problem has been proved to be an NP-hard problem. Many algorithms such as simulation annealing algorithm, genetic algorithm and other heuristic algorithms have been proposed to solve twodimensional and three-dimensional packing problem. To solve the cube packing problem with time schedule, this paper first introduces some concepts such as packing level, space distance and average neighbor birth order and then proposes a greedy algorithm. The algorithm tries every feasible corner greedily to calculate the space utilization, packing level, space distance, average neighbor birth order of this placement, and chooses the best placement according to these criteria. Theoretical analysis indicates that the time complexity of this algorithm is O(A2B2C2T 2n5). The experiments show that the average space utilization of non-guillotine cutting test cases is 98.81%, and the average space utilization of guillotine cutting test cases achieves 99.87%. Furthermore, optimal solutions of more than half cases are achieved by this algorithm. The experimental results show that this algorithm can solve the problem of cube packing with time schedule effectively and effciently.

关键词： cube packing problem time schedule packing level space distance average neighbor birth order

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Efficient microwave-assisted photocatalytic degradation of endocrine disruptor dimethyl phthalate over composite catalyst ZrO_x /ZnO

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Journal of environmental Sciences 2010年第11期22卷 1800-1806页

作者： Wenchao Liao, Tong Zheng, Peng Wang, Sisi Tu, Weiqian PanState key laboratory of Urban Water Resource and environment, School of Municipal and environmental Engineering, Harbin Institute of Technology, Harbin 150090, china. [a] State key laboratory of Urban Water Resource environment School of Municipal environmental Engineering Harbin Institute of Technology Harbin 150090 China

A highly active ZrO x /ZnO catalyst for microwave-assisted photocatalytic （MW/PC） degradation of endocrine disruptor dimethyl phthalate （DMP） has been prepared via cetyltrimethylammonium assisted hydrothermal method. The ZrO x /ZnO was characterized by XPS, XRD, UV-Vis, BET and SEM techniques. The XPS result showed that Zr oxides with different valences （＋2, ＋3, ＋4） co-existed in ZrO x /ZnO. By using the ZrO x /ZnO （0.1 g）, the TOC removal efficiency of DMP （100 mL of 50 mg/L） was 88% after 30 min reaction, which was about 15% higher than P25 TiO 2 . It was found that the removal process of DMP by MW/PC followed pseudo first-order kinetics in all cases, and ZrO x /ZnO significantly accelerated the degradation of DMP. The degradation half-life time of DMP was shortened 45% compared with P25 TiO 2 . A possible catalytic mechanism was proposed based on microwave response and interfacial charge transfer. ZrO x /ZnO could be reused for six times without obvious decrease in catalytic activity. The study offers new insights into designing highly efficient catalysts for MW/PC process and is applicable for MW/PC environmental remediation.

关键词： ZrO_x /ZnO microwave-assisted photocatalysis dimethyl phthalate

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Microstructures of an AlSi_7Mg alloy by near-liquidus casting

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Rare Metals 2007年第3期26卷 226-229页

作者： GAO Ming WANG Ping LU Guimin CUI Jianzhong School of Physics Science ＆ Technology Shenyang Normal University Shenyang 110034 China key laboratory for Microstructure ＆ properties of Advanced Materials Education Committee of Liaoning Province Shenyang Normal UniversityShenyang 110034 China key laboratory of electromagnetic Processing of Materials Ministry of Education Northeastern University Shenyang 110004 China

Semi-solid ingots of an A1SiTMg alloy were obtained using the method of near liquidus casting. Their microstructures exhibit the characteristics of free, equiaxed, and non-dendrite, which are required for semi-solid forming. The influences of casting temperature, heat preservation time, and cooling rate on the microstructure were also investigated. The results show that in the temperature region near liquidus the grain size becomes small with a decrease in casting temperature. Prolonging the heat preservation time makes grain crassitude at the same temperature. And increasing the cooling rate makes grain fine. The microstructure of the alloy cast with iron mould is freer than that with graphite mould.

关键词： semi-solid near-liquidus casting AlSi7Mg alloy microstructure global grains

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Preparation of anatase TiO_2 with assistance of surfactant OP-10 and its electrochemical properties as an anode material for lithium ion batteries

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Rare Metals 2010年第5期29卷 505-510页

作者： YI Jin,TAN Chunlin,LI Weishan,LEI Jianfei,and HAO Liansheng School of Chemistry and environment & key laboratory of Electrochemical Technology on Energy Storage and Power Generation of Guangdong Higher Education Institutes,South china Normal University,Guangzhou 510006,china School of Chemistry and environment & key laboratory of Electrochemical Technology on Energy Storage and Power Generation of Guangdong Higher Education Institutes South China Normal University Guangzhou China

With the assistance of nonionic surfactant （OP-10） and surface-selective surfactant （CH3COOH）, anatase TiO2 was prepared as an anode material for lithium ion batteries. The morphology, the crystal structure, and the electrochemical properties of the prepared anatase TiO2 were characterized by scanning electron microscopy （SEM）, X-ray diffraction （XRD）, electrochemical impedance spectroscopy （EIS）, and galvanostatic charge and discharge test. The result shows that the prepared anatase TiO2 has high discharge capacity and good cyclic stability. The maximum discharge capacity is 313 mAh.g^-1, and there is no significant capacity decay from the second cycle.

关键词： lithium ion batteries titanium dioxide sol-gel process electrochemical properties sttrfactants

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A new grid-associated algorithm in the distributed hydrological model simulations

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Science china(Technological Sciences) 2010年第1期53卷 235-241页

作者： XU Rui1,2,HUANG XiaoXue1,LUO Lin1 & LI ShaoCai3 1 State key laboratory of Hydraulics and Mountain River Engineering College of Architecture and environment,Sichuan University,Chengdu 610065,china 2 College of Electronic Engineering,Guilin University of Electronic Technology,Guilin 541004,china 3 College of Life Sciences,Sichuan University,Chengdu 610065,china 1. State key laboratory of Hydraulics and Mountain River Engineering College of Architecture and environment Sichuan University Chengdu 610065 China2. College of Electronic Engineering Guilin University of Electronic Technology Guilin 541004 China3. College of Life Sciences Sichuan University Chengdu 610065 China

This paper presents a new grid-associated algorithm to improve the performance of a D8 algorithm based distributed hydrological model *** algorithm is based on the well known single-flow D8 algorithm of grid *** algorithm allocates calculation priorities according to the distance between the units and the outlet,then carries out the ergodic computations of the hydrological units according to the priority *** the parallelized algorithm,a standard thread-level shared memory system for parallel programming(OpenMP-Open specifications for Multi Processing) was introduced,and the parallel coding was implemented in C lan-guage.A case study showed that the absolute speed-up ratio of the grid-associated algorithm is 1.64 over the original D8 algorithm,and the linear speed-up ratio of the parallel associated algorithm is 2.42 under 4 *** parallel grid-associated algorithm can be applied to a variety of research fields that use the grid method.

关键词： distributed hydrological model grid-association algorithm OpenMP parallel computing

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Estimation on principal component of multi-collinearity Gauss-Markov model based on minimum description length

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中国有色金属学会会刊：英文版 2005年第S1期15卷 153-155页

作者： SHI Yu-feng~(1, 2) (1. Shandong University of Technology, Zibo 255049, china 2. key laboratory of Geospace environment and Geodesy, Ministry of Education, Wuhan University, Wuhan 430079, china) Shandong Univ Technol Zibo 255049 Peoples R China Wuhan Univ Minist Educ Key Lab Geospace Environm & Geodesy Wuhan 430079 Peoples R China

Gauss-Markov model is frequently used in data analysis; the analysis and estimation of its parameters is always a hot issue. Based on the information theory and from the viewpoint of optimal information on description—minimum description length, this paper discusses a case: where there is multi-collinearity in the coefficient matrix, principal component estimation is used to estimate and select the original parameters, so as to reduce its multi-collinearity and improve its credibility. From the viewpoint of minimum description length, this paper discusses the approach of selecting principal components and uses this approach to solve a practical problem.

关键词： minimum description length Gauss-Markov model multi-collinearity principal component estimation

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Holographic QSAR of estradiol derivatives

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Chinese Science Bulletin 2003年第7期48卷 642-645页

作者： CUI Shihai, LIU Shushen, WANG Xiaodong & WANG Liansheng State key laboratory of Pollution Control and Resource Reuse, School of environment, Nanjing University, Nanjing 210093, china 1. State key laboratory of Pollution Control and Resource Reuse School of Environment Nanjing University Nanjing 210093 China

Holographic QSAR model is constructed to predict relative binding affinities of estradiol derivatives with lamb uterine estrogen receptor. The method does not require the generation of three-dimensional structure of the compounds. The factors that influence the quality of QSAR model are discussed. The result indicates that the model has good predictability and yields a high q2LOO value of 0.897. Compared to other QSAR methods, the HQSAR technique is suitable for use in screening large database of chemicals.

关键词：雌二醇衍生物全息结构性质相关性内分泌紊乱化合物紊药物分析

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