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Simulating the transfer and fate of hexachlorocyclohexane in recent 50 years in beijing, china

Science china Earth Sciences 2005年第12期48卷 2203-2213页

作者： CAO Hongying1, LIANG Tao1 & TAO Shu2 1. Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, beijing 100101, china 2. Laboratory for Earth Surface Processes, Peking University, beijing 100871, china 1. Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences 100101 Beijing China 2. Laboratory for Earth Surface Processes Peking University 100871 Beijing China

Taking beijing as a study area, a dynamic fugacity model was used to simulate the transfer and fate of technical HCHs according to the physic-chemical properties of the studying environment and HCH isomers. Dynamic changes of the transfer fluxes and concentrations of HCH isomers during 1952―2003.were simulated and the model results suggest good agreement between the calculated and measured concentrations of HCH isomers. During 1952―1983. the average input and output amount of HCHs through agricultural application and degradation are 13. t and 150 t respectively. The dominant transfer processes of HCHs in the study area are air-soil deposition, soil erosion and soil-air diffusion, transfer fluxes of these processes are 80 t?a?1, 16 t?a?1 and 11 t?a?1, which account for 92% of total transfer fluxes of HCHs isomers. There were approximately 253. HCHs in all environmental compartments of the study area during this period and 97% of which existed in soil compartment. Air and water advection became the dominant input sources of HCHs after 1984 when the application of technical HCHs was prohib-ited, concentration of HCHs quickly descended to a quite low level in several years. Total amount of HCHs isomers remaining in the study area environment now is less than 5% that before 1983. and this percentage may descend to 0.5% after 20 years by prediction.

关键词： fugacity model, hexachlorocyclohexane, compartment, transfer flux, fate.

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Multiple time scale evaluation of the energy balance during the maize growing season,and a new reason for energy imbalance

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Science china Earth Sciences 2009年第1期52卷 108-117页

作者： GUO JianXia1,2,BIAN LinGen3.& DAI YongJiu2 1 Meteorological Observation center of china Meteorological Administration,beijing 100081,{3. 2 State Key Laboratory of Remote Sensing Science,School of Geography and Remote Sensing Science,beijing Normal University,beijing 100875,{3. 3.Chinese Academy of Meteorological Sciences,beijing 100081,{3. Meteorological Observation center of china Meteorological Administration Beijing 100081 China State Key Laboratory of Remote Sensing Science School of Geography and Remote Sensing Science Beijing Normal University Beijing 100875 China

Energy imbalance is a common problem associated with the measurement of surface energy using the eddy covariance *** the evaluation of the energy balance,people usually pay more attention to the statistical result that the effective energy(the sum of sensible and latent heat) is systematically lower than the available energy(the difference of net radiation and ground heat flux).However,little attention has been paid to the existence of the reversed situation when the effective energy is larger than the available energy or their contribution to the overall energy closure *** this paper,based on the analysis of the energy balance on multiple time scales across the maize growth season,we conclude that the non-synchronization of energy components is the main reason for the existence of the reversed *** shifting the phase of the effective energy components half an hour ahead,the rates of energy closure over all time scales are improved and dramatically reduce the number of the half-hourly samples when the energy ratio exceeds 1 or is below *** to the characteristics of the energy distribution and transformation over multiple time scales,latent heat is always the main type of energy cost,and the residual of the energy balance increases with the growth of the maize plant surpassing the sensible heat for seventy *** is suggested that the heat storage and photosynthetic energy play an important role in the energy balance during the growing period of maize.

关键词： maize energy balance multiple time scale energy hysteresis

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Application and Comparison of SST Model in Numerical Simulation of the Axial Compressors

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Journal of Thermal Science 2010年第4期19卷 300-309页

作者： YIN Song~1,JIN Donghai~2,GUI Xingmin~3.and ZHU Fang Aero-Engines Simulation Research center,School of Jet Propulsion,beijing University of Aeronautics and Astronautics, beijing,100191,{3. Aero-Engines Simulation Research center School of Jet Propulsion Beijing University of Aeronautics and Astronautics Beijing China

The shear-stress transport(SST)turbulence model is incorporated into Navier-Stokes equations to simulate a turbomachinery flowfield.A staggered finite volume method is used to make the mean flow equations and turbulence model equations strongly coupled and enhance the stability of the numerical *** implicit treatment of the source terms is applied to the SST model.A steady state solution is obtained using five-stage Runge-Kutta time-stepping scheme with local time stepping and residual smoothing to accelerate convergence. The wall distance d,a key parameter in the SST model,is solved by a partial differential *** validations of the code are conducted on rotor 3.,wp11 at design and off-design conditions by comparison with measurements and the Spalart-Allmaras(SA)turbulence *** flow within the tip is calculated with a multi-block grid.

关键词： SST model staggered finite volume method turbomachinery simulation multi-block grid

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Robust multiuser MIMO scheduling algorithms with imperfect CSI

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Science china(Information Sciences) 2012年第4期55卷 815-826页

作者： MAO JunLing 1,3.GAO JinChun 1,3.LIU YuanAn 1,3.XIE Gang 2,3.& ZHANG Jian 1,3.1 School of Electronic Engineering,beijing University of Posts and Telecommunications,beijing 100876,china 2 School of Information and Communication Engineering,beijing University of Posts and Telecommunications,beijing 100876,china 3.Key Lab of Universal Wireless Communications,Ministry of Education,beijing University of Posts and Telecommunications,beijing 100876,china 1. School of Electronic Engineering Beijing University of Posts and Telecommunications Beijing 100876 China3. Key Lab of Universal Wireless Communications Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China2. School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

Robust multiuser multiple-input-multiple-output (MIMO) scheduling algorithms are proposed in this *** imperfect channel state information (CSI),traditional scheduling algorithms for the multiuser MIMO system based on the zero forcing precoding scheme will lose some performance due to the multi-user interference (MUI).In order to improve the system average throughput,we study the robust multiuser MIMO scheduling problem with imperfect *** the average capacity formula,we derive a robust factor which can transform the robust multiuser MIMO scheduling problem into the traditional one,thus most existing non-robust scheduling algorithms can be robust if this factor is *** results show that compared with the traditional algorithms,the proposed robust algorithms can improve the system average throughput significantly under the CSI error environment.

关键词： multiuser MIMO (MU-MIMO) scheduling robust imperfect CSI

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Corrosion and electrochemical behavior of as-cast Mg-5Y-7Gd-1Nd-0.5Zr magnesium alloys in 5%NaCl aqueous solution

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Progress in Natural Science:Materials International 2011年第4期21卷 314-321页

作者： Xin ZHANG~(1,2,3.,Kui ZHANG~1,Xing-gang LI~1,Cong WANG~4,Hong-wei LI~(2,3.,Chang-shun WANG~(2,3.,Xia DENG~1 1.State Key Laboratory for Fabrication and Processing of Nonferrous Metals, beijing General Research Institute for Nonferrous Metals,beijing 100088,china 2.beijing Engineering Research center for Advanced Manufacturing and Evaluation of Special Vehicle Parts,beijing 100072,china 3.Institute of Technology,beijing North Vehicle Group Corporation,beijing 100072,china 4.Fengtai Military Representative Office,beijing Military Representative Office,PLA,beijing 100072,china [a] State Key Laboratory for Fabrication and Processing of Nonferrous Metals Beijing General Research Institute for Nonferrous Metals Beijing 100088 China [b] beijing Engineering Research center for Advanced Manufacturing and Evaluation of Special Vehicle Parts Beijing 100072 China [c] Institute of Technology Beijing North Vehicle Group Corporation Beijing 100072 China [d] Fengtai Military Representative Office Beijing Military Representative Office PLA Beijing 100072 China

The corrosion mechanism of the as-cast Mg-5Y-7Gd-1Nd-0.5Zr magnesium alloy immersed in 5%NaCl aqueous solution was investigated by electrochemical test and *** electrochemical results indicate that the corrosion resistance of Mg-5Y-7Gd-1Nd-0.5Zr alloy in 5%NaCl aqueous solution gradually deteriorates with immersion time increasing from 2 h,24 h,60 h,to 108 h,which is consistent with the SEM observation of corrosion *** Cl-anion leads to the initiation and development of the corrosion pits,and Mg-5Y-7Gd-1Nd-0.5Zr alloy exhibits filiform type of attack under significant anodic control of magnesium solution *** corrosion potential becomes noble with increasing immersion time.

关键词： magnesium alloys Mg-5Y-7Gd-1Nd-0.5Zr corrosion electrochemical behavior

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Synthesize TiO_2 microspheres self-assembled from nanorods via hydrothermal treatment

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Science china Chemistry 2007年第2期50卷 175-178页

作者： ZHANG YiBing1,2,FENG XinJian3.& JIANG Lei2,3.1 Shangrao Teachers’ College,Shangrao 3.4001,china 2 National center for Nanoscience and Nanotechnology,beijing 100080,china 3.Institute of Chemistry,Chinese Academy of Sciences,beijing 100080,china 1. Shangrao Teachers’ College Shangrao 334001 China 2. National center for Nanoscience and Nanotechnology Beijing 100080 China 3. Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China

The TiO2 microspheres were deposited on the glass substrates under certain conditions via hydro-thermal reaction using 0.15 mol·L?1 TiCl3.saturated NaCl aqueous solution adding urea as an additive. The TiO2 is characterized rutile by results of SEM,TEM and XRD techniques,the TiO2 microspheres are large scale assembled from TiO2 nanorods. The affections on the products by the factors of the con-tents of urea being an additive(the key techniques) ,the reaction temperature,the reaction time and the concentration of TiCl3.were studied. The optimum condition was found,and the mechanism of reac-tions was discussed also.

关键词： TiO2 self-assembly nanorods microsphere hydrothermal reaction

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A mixed method for measuring low-frequency acoustic properties of macromolecular materials

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Science china(Physics,Mechanics & Astronomy) 2006年第6期49卷 729-739页

作者： LIU Hongwei1,YAO Lei1,3.ZHAO Hong1,3.ZHANG Jichuan2,3.& XUE Zhaohong2 1. National Key Laboratory of Acoustics,Institute of Acoustics,Chinese Academy of Sciences,beijing 100080,china 2. Institute of Chemistry,Chinese Academy of Sciences,beijing 100080,china 3. Graduate University of Chinese Academy of Sciences,beijing 100049,china National Key Laboratory of Acoustics Institute of Acoustics Chinese Academy of Sciences Beijing 100080 China Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

A mixed method for measuring low-frequency acoustic properties of macro-molecular materials is presented. The dynamic mechanical parameters of materials are first measured by using Dynamic Mechanical Thermal Apparatus(DMTA) at low frequen-cies,usually less than 100 Hz; then based on the Principles of Time-Temperature Super-position (TTS),these parameters are extended to the frequency range that acousticians are concerned about,usually from hundreds to thousands of hertz; finally the extended dynamic mechanical parameters are transformed into acoustic parameters with the help of acoustic measurement and inverse analysis. To test the feasibility and accuracy,we measure a kind of rubber sample in DMTA and acquire the basic acoustic parameters of the sample by using this method. While applying the basic parameters to calculating characteristics of the sample in acoustic pipe,a reasonable agreement of sound absorp-tion coefficients is obtained between the calculations and measurements in the acoustic pipe.

关键词： low-frequency acoustic properties,dynamic mechanical properties,Principles of Time-Temperature Superposition,acoustic pipe,sound absorption coefficient.

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2.5-dimensional angle potential field algorithm for the real-time autonomous navigation of outdoor mobile robots

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Science china(Information Sciences) 2011年第10期54卷 2100-2112页

作者： QIU Quan 1,3.& HAN JianDa 2 1 beijing Research center of Intelligent Equipment for Agriculture,beijing 100097,{3. 2 State Key Laboratory of Robotics,Shenyang Institute of Automation,Chinese Academy of Sciences,Shenyang 110016,{3. 3.National Research center for Intelligent Agricultural Equipment,beijing 100097,{3. 1. beijing Research center of Intelligent Equipment for Agriculture Beijing 100097 China3. National Research Center for Intelligent Agricultural Equipment Beijing 100097 China2. State Key Laboratory of Robotics Shenyang Institute of Automation Chinese Academy of Sciences Shenyang 110016 China

A new real-time algorithm for the autonomous navigation of mobile robots equipped with laser scanners is proposed in this *** from the existing algorithms designed for 2-dimensional navigation problems,the new algorithm introduces the height information of the obstacles into the guidance process and behaves as a 2.5-dimensional angle potential field algorithm (2.5D-APF) to fulfill the navigation requirements under complex outdoor terrain ***,one laser scan is partitioned into two kinds of function sectors: guidance sector and inspecting ***,the guidance sector and the inspecting sectors are reconstructed to form a virtual guidance scan,where the 2.5D information is taken into ***,the conventional APF is improved to analyze the virtual guidance scan and generate the navigation *** new algorithm is tested on a tracked mobile robot,and the experimental results validate the proposed algorithm.

关键词： robot 2.5-dimensional outdoor real-time autonomous navigation

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Metallogenic characteristics of epithermal gold deposits in Tianshan, Xinjiang, china

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Chinese Science Bulletin 1999年第S2期44卷 138-139页

作者： FENG Jianzhong~1, FU Shuixing~2, WU Dewen~3.and YANG Zian~3.1. Department of Geology, Peking University, beijing 100871, china 2. beijing Institute of Geology for Mineral Resources, beijing 100012, china 3. center of Remote Sensing for Geology, CNNC, beijing 101601, china Department of Geology Peking University Beijing 100871 China beijing Institute of Geology for Mineral Resources Beijing 100012 China center of Remote Sensing for Geology CNNC Beijing 101601 China

TIANSHAN in southern Xinjiang belongs to the Paleozoic island arc system in which volcanic rocks are extensively distributed. A series of epithermal gold deposits such as the Axi, Xitan, Cuiling andShuangfengshan gold deposits have been discovered. 1 Geological settings of epithermal gold deposits in Tianshan, southern Xinjiang Tianshan in southern Xinjiang belongs to the Paleozoic island arc system. To its north is the Kazakhstan plate, and to its north is the Tarim plate. From west to east, the tectonic units are characterizedby Yili island arc, southern Tianshan arc-basin, Jiaoluotage island arc and Xingxingxia island arc. TheEW-trending Tianshan ore belt is controlled by Kanggurtag geosuture. In its west part, it is controlled byShenglidaban geosuture. The linear structure is NNW-trending; from north to south, the faults

关键词： metallogenic characteristics gold deposits Tianshan Xinjiang.

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Isomerization of B_6,B_6^- and B_6^+ clusters

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Science china Chemistry 2010年第1期53卷 202-209页

作者： WEI GongMin1,PU ZhiFeng2,ZOU Rong3.LI GuoLiang2,3.& LUO Qiong2,3.1Department of Physics,Capital Normal University,beijing 100048,china 2State Key Laboratory of Explosion Science and Technology beijing Institute of Technology,beijing 100081,china 3.5} for Computational Quantum Chemistry,South china Normal University,Guangzhou 51063.,china 1. Department of Physics Capital Normal University Beijing 100048 China2. State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology Beijing 100081 China3. Center for Computational Quantum Chemistry South China Normal University Guangzhou 510631 China

The interconversions between isomers with the same spin multiplicity of neutral B6 and charged B6-and B6+ clusters have been investigated at the B3.YP/6-3.1+G level of theory,including determination of the minimum energy pathways with transition states connecting the corresponding reactants and *** dynamic calculations,26 isomers were optimized,including 11 novel *** order to further refine the energies,single-point B3.YP/6-3.1+G(3.f) calculations were carried out on the corresponding B3.YP/6-3.1+G geometries of all isomers of B6,B6-and B6+ and the corresponding isomerization transition *** stability of each isomer of B6(singlet and triplet states),B6-(doublet state) and B6+(doublet state) was analyzed from both thermodynamic and dynamic viewpoints.

关键词： B6 transition state intrinsic reaction coordinate barrier height

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