检索结果-南通市图书馆

Droplet creator based on electrowetting-on-dielectric for lab on a chip

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2006年第2期49卷 248-256页

作者： ZENG Xuefeng1. YUE Ruifeng1. WU Jiangang1. HU Huan1. DONG Liang1. WANG Zheyao1. HE Feng2 & LIU Litian1.1. Institute of Microelectronics, tsinghua University, {1., china 2. Department of Engineering Mechanics, tsinghua University, {1., china 1. Institute of Microelectronics Tsinghua University Beijing 100084 China 2. Department of Engineering Mechanics Tsinghua University Beijing 100084 China

Electrowetting-on-dielectric (EWOD) is to directly control the wettability of liquids on the solid surface by applying the electric potential to the microelectrode array under the dielectric layer. The prototype of the EWOD droplet creator with the sandwiched structure is used: the droplet is sandwiched between the top and bottom plates; the bot- tom plate consists of silicon used as the substrate of the microelectrode array, nitride sili- con film deposited by low pressure chemical vapor deposition as the dielectric layer and the fluorocarbon polymer film deposited by inductively coupled plasma chemical vapor deposition as the hydrophobic layer; and the top plate is the transparent electrode covered with the hydrophobic layer. To obtain the required minimum voltage, the process and the criterion of creating droplets are analyzed. At the voltage of 35 V the deionized water droplet surrounded in silicone oil is successfully created.

关键词： micro total analysis system, electrowetting-on-dielectric, creation and control of droplets, inductively coupled plasma chemical vapor deposition.

Forecasting the summer rainfall in North china using the year-to-year increment approach

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2009年第4期52卷 532-539页

作者： FAN Ke1. LIN MeiJing1.2 & GAO YuZhong3 1.Nansen-Zhu International research {1., Institute of Atmospheric Physics, Chinese Academy of Sciences, beijing 1.0029, china 2 Graduate University of the Chinese Academy of Sciences, beijing 1.0049, china 3 Heilongjiang Meteorological Administration, Harbin 1.0030, china Nansen-Zhu International research {1. Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Graduate University of the Chinese Academy of Sciences Beijing 100049 China Heilongjiang Meteorological Administ

A new approach to forecasting the year-to-year increment of rainfall in North china in July-August (JA) is proposed. DY is defined as the difference of a variable between the current year and the preceding year (year-to-year increment). NR denotes the seasonal mean precipitation rate over North china in JA. After analyzing the atmospheric circulation anomalies associated with the DY of NR, five key predictors for the DY of NR have been identified. The prediction model for the DY of NR is established by using multi-linear regression method and the NR is obtained (the current forecasted DY of NR added to the preceding observed NR). The prediction model shows a high correlation coefficient (0.8) between the simulated and the observed DY of NR throughout period 1.65-1.99, with an average relative root mean square error of 1.% for the percentage of precipitation rate anomaly over North china. The prediction model makes a hindcast for 2000-2007, with an average relative root mean square error of 21. for the percentage of precipitation rate anomaly over North china. The model reproduces the downward trend of the percentage of precipitation rate anomaly over North china during 1.65-2006. Because the current operational prediction models of the summer precipitation have average forecast scores of 60%-70%, it has been more difficult to forecast the summer rainfall over North china. Thus this new approach for predicting the year-to-year increment of the summer precipitation (and hence the summer precipitation itself) has the potential to significantly improve operational forecasting skill for summer precipitation.

关键词： annual increment North china precipitation prediction prediction skill

Joint exploration of crustal structure in Fuzhou basin and its vicinities by deep seismic reflection and high-resolution refraction as well as wide-angle reflection/refraction

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2005年第7期48卷 925-938页

作者： ZHU Jinfang1. XU Xiwei2, ZHANG Xiankang3, HUANG Zonglin1. CHEN Xiangxiong1. FANG Shengming3, LIU Baojin3, ZHENG Rongzhang2,4 1. Seismological Bureau of Fujian Province,Fuzhou 350003,china 2. Institute of Geology,china Earthquake Administration,beijing 1.0029,china 3. research center for Exploration Geophysics,china Earthquake Administration,Zhengzhou 450002,china 4. State Key Laboratory of Earthquake Dynamics,Institute of Geology,china Earthquake Administration,beijing 1.0029,china Seismological Bureau of Fujian Province Fuzhou 350003 China Institute of Geology China Earthquake Administration Beijing 100029 China research {1. for Exploration Geophysics China Earthquake Administration Zhengzhou 450002 China State Key Laboratory of Earthquake Dynamics Institute of Geology China Earthquake Administration Beijing 100029 China

The Fuzhou basin and its vicinities are located at the northern end of the southeastern coastal seismic zone of the mainland of china. By the joint explorations of high-resolution seismic refraction and wide-angle reflection/refraction as well as deep seismic reflection in the region, which is the first synthetic profile in china, its fine velocity structure and geometric structure from the ground to Moho discontinuity is obtained. The result shows that the crust is obviously layered with a thickness of about 32 km. Basically, it consists of two parts: upper crust and lower crust. The velocity of the upper crust is 5.9-6.2 km/s in which there is a 3-4-km-thick weak low-velocity layer between the depths of 1.-1. km, while the velocity of the lower crust in the range of 6.3-7.2 km/s. There exists a strong velocity gradient layer about 3 km thick above the Moho discontinuity whose velocity increases from 6.5 to 7.27 km/s. There exist high-angle normal faults that are small in size and extend only in the shallow crust. These faults are the secondary developed on the hanging wall of westward dipping low-angle normal faults. Thus, their seismogenic ability is limited, however, there exists a high-angle deep fault in the crust from Changle-Zaoan fault zone to seashore fault zone. This deep fault has cut the interface between the upper and lower crusts and Moho discontinuity, and may be the deep structure to trigger destructive earthquake source in future to affect Fuzhou City. These results have advanced the detecting precision of the deep structure in the southeastern coastal seismic zone of the mainland of china. In the aspect of the combined feature of the deep and shallow extensional structures that consist of the westward dipping low-angle normal faults and secondary normal faults on their hanging walls in the upper crust, it is firstly obtained that a united structural interpretation has deepened the knowledge about the deep dynamic process in the southeastern coasta

关键词： deep seismic reflection high-resolution seismic refraction wide-angle.

A quantification model for apoptosis in mouse embryos in the early stage of fetation

在线全文

学校读者我要写书评

暂无评论

Science china(Life Sciences) 2009年第10期52卷 922-927页

作者： WANG PengFei1. FU JianHua1. MA WanYun1. CHEN DieYan1. Lü DanYu2 & BAI WenJia3 1.Key Laboratory for Atomic and Molecular Nanosciences of Education Ministry, Department of Physics, tsinghua University, {1., china 2 Department of Anatomy & Histology and Embryology, School of Basic Medical Sciences Peking University Health Science center, beijing 1.0083, china 3 Department of Automation, tsinghua University, {1., china 1. Key Laboratory for Atomic and Molecular Nanosciences of Education Ministry Department of Physics Tsinghua University Beijing 100084 China 2. Department of Anatomy & Histology and Embryology School of Basic Medical Sciences Peking University Health Science Center Beijing 100083 China 3. Department of Automation Tsinghua University Beijing 100084 China

Apoptosis is the most important inducement and modulator for embryos in the early stage of fetation, i.e. after the 8-cell stage, mostly the morula and blastula stage, to proceed to the stage of nonlinear development. Using a two-photon laser scanning microscopy (TPLSM) system, we obtained 3-dimensional (3D) fluorescent images of preimplantation mouse embryos. A model for quantification was established. The statistical results for the spatial location of apoptosis bodies in embryos was obtained following image processing, as well as investigation of the kinetics of apoptosis. It was found that most (70%) apoptosis occurred in the trophectoderm, and the departure between the centroid and geometric center of embryos had a step transition when embryos developed into the 32-cell stage, which was consistent with the theoretical prediction that the blastocele would induce a symmetry break of the distribution of cells in embryos.

关键词： apoptosis preimplantation mouse embryo TPLSM quantification model

Simulation studies of high-latitude magnetospheric boundary dynamics

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2004年第4期47卷 421-435页

作者： PU Zuyin1. SHI Quanqi1.3, XIAO Chijie1. FU Suiyan1. ZHANG Hui1.2, ZONG Qiugang2 & LIU Zhenxing3 1. School of Earth and Space Sciences, Peking University, beijing 1.0871. {1. 2. center for Space Physics, Boston University, 725 Commonwealth Avenue, Boston, MA 0221., USA 3. center for Space Science and Application research, Chinese Academy of Sciences, beijing 1.0080, {1. 1. School of Earth and Space Sciences Peking University 100871 Beijing China 2. center for Space Science and Application {1. Chinese Academy of Sciences 100080 Beijing China 3. center for Space Physics Boston University 725 Commonwealth Avenue 02215 Boston MA USA

Magnetic reconnection at the high-latitude magnetopause is studied using 2.5-dimensional Hall-MHD simulation. Concentric flow vortices and magnetic islands appear when both Hall effect and sheared flow are considered. Plasma mixing across the magnetopause occurs in the presence of the flow vortices. Reconnected structure generated in the vicinity of the subsolar point changes its geometry with increasing flow shear while moving to high latitudes. In the presence of flow shear, with the Hall-MHD reconnection a higher reconnection rate than with the traditional MHD is obtained. The out-of-plane components of flow and magnetic field produced by the Hall current are redistributed under the action of the flow shear, which makes the plasma transport across the boundaries more complicated. The simulation results provide some help in understanding the dynamic processes at the high latitude magnetopause.

关键词： magnetopause, entry layer, magnetic reconnection, vortex reconnection, Hall effect, flow shear.

Biogas recovery from microwave heated sludge by anaerobic digestion

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2010年第1期53卷 144-149页

作者： QIAO Wei1.WANG Wei2,ZHU CuiPing3 & ZHANG ZhongZhi1.1.College of Chemical Science and Engineering,china University of Petroleum,{1. 1.2249,china 2 Department of Environmental Science and Engineering,tsinghua University,{1. 1.084,china 3 J & K china Cleaning Energy Technology Co.Ltd.,{1. 1.0085,china 1. College of Chemical Science and Engineering China University of Petroleum Beijing 102249 China2. Department of Environmental Science and Engineering Tsinghua University Beijing 10084 China3. J & K China Cleaning Energy Technology Co. Ltd. Beijing 100085 China

Biogas generated from sewage sludge,livestock waste,and food waste by anaerobic digestion is a valuable renewable energy ***,conventional anaerobic digestion is not an efficient process.A long hydraulic retention time and low biogas recovery rate hinder the applications of those *** effective pretreatment method to destroy sludge microbial cells has been one of the major concerns regarding improvement of the biogas *** article focuses on the effects of microwave heating on sludge anaerobic *** suspended solid(VSS) and chemical organic demand solubilization of heated sludge were *** heating was found to be a rapid and efficient process for releasing organic substrates from *** increase of organic dissolution ratio was not obvious when holding time was over 5 min with microwave *** effect of the VSS solubilization was primarily dependent on heating *** highest value of VSS dissolving ratio,36.4%,was obtained at 1.0°C for 30 *** COD dissolving ratio was about 25% at 1.0°*** organic carbon of treated sludge liquor was 1.98 and 2.73 g/L at 1.0°C and 1.0°C for 5 min,respectively.A biochemical methane potential(BMP) test of excess sludge and a mixture of primary and excess sludge demonstrated an increase in biogas *** total biogas from microwave treated mixture sludge increased by 1..9% to 20.2% over control after 30 days of *** production was 1..1. to 25.9% higher for excess sludge than for untreated *** VS removal ratios of mixture sludge and excess sludge were 1.% and 1.% higher,respectively,compared to the untreated sludge.

关键词： biogas recovery microwave heating sludge anaerobic digestion

Effect of upward ion on field-aligned currents in the near-earth magnetotail

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2007年第5期50卷 673-680页

作者： ZHANG LingQian1. LIU ZhenXing1. MA ZhiWei2, SHEN Chao1. ZHOU XuZhi3 & ZHANG XianGuo3 1.center for Space and Applied {1., Chinese Academy of Sciences, beijing 1.0080, china 2 Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031. china 3 School of Earth and Space Science, Peking University, beijing 1.0871. china 1. center for Space and Applied {1. Chinese Academy of Sciences Beijing 100080 China 2. Institute of Plasma Physics Chinese Academy of Sciences Hefei 230031 China 3. School of Earth and Space Science Peking University Beijing 100871 China

A 3-dimensional resistive MHD simulation was carried out to study the effect of the upward ions on the field-aligned currents (FACs) in the near-earth magnetotail. The simulation results show that the up-flow ions originating from the nightside auroral oval would drift into the center plasma sheet along the magnetic field lines in the plasma sheet boundary, and have an important effect on the field-aligned currents. The main conclusions include that: 1. the upward-ions mainly affect the field- aligned currents in the near-earth magnetotail (inside 1. Re); 2) the generated FACs in the near-earth region have two types, i.e., Region 1.FAC in the high-latitude and Region 2 FAC in the low-latitude; 3) FACs increase with the enhancement of the upward ion flux; 4) with the same flux of the upward ions, FACs enhance with the increase of the velocity of the up-flow ions; 5) the intensification of FACs is also closely related with the latitude of the upward ions, and the ions from the closed field line region generate larger FACs; 6) the generation of FACs is closely related with By created by the upward ions.

关键词： up-flow ions, near-earth magnetotail, field-aligned current

N_2O emissions from agricultural soils in the North china Plain: the effect of chemical nitrogen fertilizer and organic manure

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2000年第4期12卷 463-468页

作者： DONG Yun\|she 1.2,3 , Dieter Scharffe 2, Manfred Domroes 3, QI Yu chun 1. ZHANG Shen 1.(1. Institute of Geographic Sciences and Natural Resources research, Chinese Academy of Sciences, {1. 1.01.1. china E\|mail: dongys@*** 2. M 中科院地理科学与资源所北京 1 0 0 1 0 Max- Planck-Institute of Chemistry 德国 Mainz 550 2 0 Mainz University 德国 Mainz 550 99

An enclosed chamber technique was used to measure N 2O emissions from intensively agricultural soils of the North china Plain during the periods of 1.95—1.96 and 1.97—1.98, to reflect distinct components of winter wheat and summer maize growing seasons. The results showed that the continuous application of fertilizer in agricultural soils increased N\-2O emissions by a factor of 24.1.28.1. the calculated annual chemical N fertilizer\|transformed N\-2O\|N emissions was 0.67%. Our results indicated that the application of organic manure also had a significant influence on soil N 2O emissions, which combined with the use of chemical N increased about 20% in a year. It was calculated that there were about 0.1.% N of organic manure transformed as N 2O N. Annual mean N 2O emission from our study area of fertilized soils was estimated to be 57.1.μgN 2O/(m 2·h). A weak correlation was also found between N 2O emissions and soil available nitrogen content NH + 4.

关键词： N_2O emissions the North china Plain agricultural soils chemical nitrogen organic manure

3D mathematical model for suspended load transport by turbulent flows and its applications

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2004年第2期47卷 237-256页

作者： LU Yongjun1.DOU Guoren1.HAN Longxi2,SHAO Xuejun3 & YANG Xianghua1.3 1.Nanjing Hydraulic research Institute,Nanjing 21.029,{1. 2.College of Environmental Engineering of Hohai University,Nanjing 21.098,{1. 3.Department of Hydraulic Engineering,tsinghua University,beijing 1.0084,{1. 1. Nanjing Hydraulic research Institute 210029 Nanjing China 2. College of Environmental Engineering of Hohai University 210098 Nanjing China 3. Department of Hydraulic Engineering Tsinghua University 100084 Beijing China

This paper presents a 3D mathematical model for suspended load transport in turbulent flows. Based on Dous stochastic theory of turbulent flow, numerical schemes of Reynolds stresses for anisotropic turbulent flows were obtained. A refined wall function was employed to treat solid wall boundaries. The equations for 2D suspended load motion and sorting of bed material have been expanded into 3D cases. Numerical results are validated by the measured data of the Gezhouba Project, and proved to be in good agreement with the experimental. The present method has been employed to simulate sediment erosion and deposition in the dam area of Three Gorges Project, and for the operation of the project, siltation process and deposition pattern in the near-dam area of the reservoir, size distribution of the deposits and bed material, and flow fields and sediment concentration fields at different time and elevations are predicted. The predicted results are close to the experimental observations in physical model studies. Thus, a new method is established for 3D simulation of sediment motion in dam areas of multi-purpose water projects.

关键词： turbulent flows, Dou's stochastic theory, nonuniform suspended load, riverbed erosion and deposition, 3D mathematical model, Three Gorges Project.