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RHEOLOGICAL BEHAVIOR OF EPOXY RESIN WATERBORNE DISPERSIONS

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Chinese Journal of Polymer Science 2001年第5期19卷 471-476页

作者： Zhen-zhong Yang Yuan-ze Xu De-lu Zhao State Key Laboratory of Polymer physics & Chemistry, center for Molecular Science {2. of Chemistry, Chinese Academy of Sciences,{3. china 中科院化学所高分子物理与化学国家重点实验室北京

The waterborne dispersions of epoxy resin were prepared by the phase inversion emulsification technique. Rheological behavior and its relationship with the structural change of the systems were studied. It was shown that the concentrated dispersions were highly viscoelastic and pseudoplastic, which was attributed to the formation of a physical network among the waterborne particles via hydrogen bond. The dilute dispersions were Newtonian fluids. The discrete clusters composed of small waterborne particles were found in diluted dispersions. With increasing solid content, there existed a structural transition via percolation through a cluster-cluster aggregation mode to form the physical network, which was qualitatively evidenced by the TEM morphologies.

关键词： epoxy resin waterborne dispersion rheological behavior cluster-cluster aggregation percolation transition

TRANSIENT EFFECT OF A BOGER FLUID FLOWING AROUND A CONFINED CYLINDER

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Chinese Journal of Polymer Science 2001年第4期19卷 377-384页

作者： Xian-feng Li Huai-tian Bu De-lu Zhao State Key Laboratory of Polymer physics and Chemistry center for Molecular Science,{2. of Chemistry, Chinese Academy of Sciences,{3., china 中科院化学所高分子物理与化学国家重点实验室北京

This paper is concerned with the numerical simulation of the transient effect of an inertialess Boger flow past a confined circular cylinder and the comparison of predictions with particle image velocimetry (PIV) measurements given by Shiang et al.. Dynamic simulation based on the Oldroyd-B constitutive model was carried out using a Lagrangian-Eulerian algorithm. The evolution of velocity field was obtained for the flow at two Deborah (De) numbers, i.e. De = 1.2.and 3.0. At low De, the flow reached steady state rapidly, and showed a symmetric flow regime. However, at high De, the time required to reach steady flow behind the cylinder increased significantly, and the distribution of the velocity field appears to be asymmetric with respect to the stagnation line. Fairly good agreement between the numerical results and the experimental observations is reported. It can be concluded that both the experimental measurements and the present simulations indicate that the elasticity of the polymeric flow strongly affect the flow regime of viscoelastic flow around a confined cylinder.

关键词： transient effect flow around a cylinder Lagrangian-Eulerian algorithm Oldroyd-B model

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

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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 Research, Chinese Academy of Sciences, beijing 100080,{2. 2.3. of Plasma physics, Chinese Academy of Sciences, Hefei 2.003.,{2. 3.School of Earth and Space Science, Peking University, beijing 100871,{2. center for Space and Applied Research Chinese Academy of Sciences Beijing China institute of Plasma physics Chinese Academy of Sciences Hefei China School of Earth and Space Science Peking University Beijing 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 15 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

Half-lives and fine structure for the α decay of deformed even-even nuclei

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Science china(physics,Mechanics & Astronomy) 2011年第S1期54卷 24-31页

作者： NI DongDong1,2.& REN ZhongZhou1,2.3.1Department of physics, Nanjing University, Nanjing 2.0093. china 2.avli {2. for Theoretical physics china, beijing 100190, china 3.11} of Theoretical Nuclear physics, National Laboratory of Heavy-Ion Accelerator, Lanzhou 73.000, china Department of physics Nanjing University Nanjing China Kavli institute for Theoretical physics{2. Beijing China center of Theoretical Nuclear physics National Laboratory of Heavy-Ion Accelerator Lanzhou China

The α-decay properties of well-deformed even-even nuclei are systematically calculated within the multichannel cluster model (MCCM). Instead of working in the WKB framework, the quasibound solution to the coupled Schro¨dinger equation is presented with outgoing wave boundary conditions, and the coupling potential is taken into full account in terms of the general quantum theories. The calculated α-decay half-lives are found to agree well with the experimental data with a mean factor of less than 2. The fine structure observed in α decay is also well reproduced by the four-channel microscopic calculation. Very strikingly, the MCCM can give relatively precise descriptions of the branching ratio to excited 4+ states, which is often overestimated in the usual WKB calculations. We expect it to be a significant development of theoretical models toward quantitative descriptions of α transitions to high-spin daughter states.

关键词： α decay half-lives cluster model coupled channel approach

Archean relic body at lower crust in Sulu area:Evidence from magnetic data

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Chinese Science Bulletin 2003年第6期48卷 589-593页

作者： WU Qifan1,2. LU Fengxiang3. LIU Qingsheng3. ZHENG Jianping3. WANG Maoji2.& WU Wenli4 1. Department of Engineering physics, Tsinghua University, {3. 100084,{2. 2. Aero Geophysical Survey & Remote Sensing {3., {3. 100083.{2. 3.{2. University of Geosciences, Wuhan 43.074,{2. 4. institute of Geophysical & Geochemical Exploration, Langfang 065000,{2. Department of Engineering physics Tsinghua University Beijing China Aero Geophysical Survey & Remote Sensing center Beijing China china University of Geosciences Wuhan China institute of Geophysical & Geochemical Exploration Langfang China

After the new 1︰1000000 aero magnetic data were processed and the three-dimensional inversion work was carried out, a vast high magnetic body northwestward was discovered. The magnetic body is located at the depth of about 2. km on the west side of Tanlu fault and at about 2. km on the east side of Tanlu fault beneath the Sulu area. There is a difference of vertical distance of 3.5 km in depth between both sides. We think that the magnetic body is an Archean metamorphic plate and belongs to the North china block. The discovery of the magnetic body is significant for us to reconstruct the structure model of the Sulu orogenic belt, delineate the suture of collision between the North china block and the Yangtze block, and estimate the depth of slipping surface when the eastside of Tanlu fault moved northward.

关键词：苏鲁地区地壳下层太古代残余体地球物理调查区域性磁场三维反演苏鲁造山带郯鲁断裂带大别-苏鲁超高压变质带

Suppressing the multimodal size distribution of InAs/GaAs quantum dots through flattening the surface fluctuation

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Science china(physics,Mechanics & Astronomy) 2010年第5期53卷 788-792页

作者： WANG Lu1,2.LI MeiCheng1,WANG WenXin2.GAO HanChao2.TIAN HaiTao2.XIONG Min1 & ZHAO LianCheng1 1 School of Material Science and Technology,Harbin institute of Technology,Harbin 150001,china 2.National Laboratory for {2. {3. physics,institute of physics,Chinese Academy of Sciences,beijing 100190,china School of Material Science and Technology Harbin Institute of Technology Harbin China National Laboratory for condensed matter {2. Institute of Physics Chinese Academy of Sciences Beijing China

A method of suppressing the multimodal size distribution of InAs/GaAs quantum dots(QDs) using molecular beam epitaxy through flattening the substrate surface is reported in this *** is found that the surface roughness plays an important role in the growth of QDs through continuous surface evolution(SEQDs).SEQDs are the main components of small QD ensemble in QDs with multimodal size *** is suggested that most of the SEQDs are very likely to nucleate during the growth interruption rather than during the *** growth of QDs on a smoother surface has largely reduced the density of *** photoluminescence line width of uniform QDs is found to be only 17 meV at a low temperature.

关键词： quantum dots multimodal surface fluctuation

Prediction model for spring dust weather frequency in North china

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Science china Earth Sciences 2008年第5期51卷 709-720页

作者： LANG XianMei center for Disastrous Climate Research and Prediction, institute of Atmospheric {2., Chinese Academy of Sciences,{3. 10002., china center for Disastrous Climate Research and Prediction Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China

It is of great social and scientific importance and also very difficult to make reliable prediction for dust weather frequency (DWF) in North china. In this paper, the correlation between spring DWF in beijing and Tianjin observation stations, taken as examples in North china, and seasonally averaged surface air temperature, precipitation, Arctic Oscillation, Antarctic Oscillation, South Oscillation, near surface meridional wind and Eurasian westerly index is respectively calculated so as to construct a prediction model for spring DWF in North china by using these climatic factors. Two prediction models, i.e. model-I and model-II, are then set up respectively based on observed climate data and the 3.4}year (1970 -2.01) extra-seasonal hindcast experiment data as reproduced by the nine-level Atmospheric General Circulation Model developed at the institute of Atmospheric physics (IAP9L-AGCM). It is indicated that the correlation coefficient between the observed and predicted DWF reaches 0.93. in the model-I, suggesting a high prediction skill one season ahead. The corresponding value is high up to 0.948 for the subsequent model-II, which involves synchronous spring climate data reproduced by the IAP9L-AGCM relative to the model-I. The model-II can not only make more precise prediction but also can bring forward the lead time of real-time prediction from the model-I’s one season to half year. At last, the real-time predictability of the two models is evaluated. It follows that both the models display high prediction skill for both the interannual variation and linear trend of spring DWF in North china, and each is also featured by different advantages. As for the model-II, the prediction skill is much higher than that of original approach by use of the IAP9L-AGCM alone. Therefore, the prediction idea put forward here should be popularized in other regions in china where dust weather occurs frequently.

关键词： spring dust weather frequency prediction model iap9l-agcm hindcast experiment real-time prediction

GENERAL DIFFERENCE SCHEMES WITH INTRINSICPARALLELISM FOR SEMILINEAR PARABOLIC SYSTEMS OFDIVERGENCE TYPE

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Journal of Computational Mathematics 1999年第4期17卷 337-352页

作者： Yu-lin Zhou Guang-wei Yuan(Laboratory of Computational physics, center of Nonlinear Studies, {2. of Applied physics and Computational Mathematics, P.O. Box 8009, beijing 100088, china) Laboratory of Computational physics Center of Nonlinear Studies Institute of Applied Physics and Computational Mathematics P.O. Box 8009 Beijing 100088 China

In this paper the general finite difference schemes with intrinsic parallelism for the boundary value problem of the semilinear parabolic system of divergence type with bounded coefficients are constructed, and the existence and uniqueness of the difference solution for the general schemes are proved. And the convergence of the solutions of the difference schemes to the generalized solution of the original boundary value problem of the semilinear parabolic system is obtained. The multidimensional problems are also studied.

关键词： difference scheme intrinsic parallelism semilinear parabolic system convergence

Systematic distortion in cosmic microwave background maps

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Science china(physics,Mechanics & Astronomy) 2009年第5期52卷 804-808页

作者： LIU Hao 1,3.&LI TiPei 1,2.1Key Laboratory of Particle Astrophysics,institute of High Energy physics,Chinese Academy of Sciences,beijing 100049,china 2.5} for Astrophysics,Tsinghua University,beijing 100084,china 3.Graduate University of Chinese Academy of Sciences,beijing 100049,china Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing China Graduate University of Chinese Academy of Sciences Beijing China center for Astrophysics Tsinghua University Beijing China

To minimize instrumentally the induced systematic errors,cosmic microwave background(CMB)anisotropy experiments measure temperature differences across the sky using pairs of horn antennas, temperature map is recovered from temperature difference obtained in sky survey through a map-making *** inspect and calibrate residual systematic errors in the recovered temperature maps is important as most previous studies of cosmology are based on these *** analyzing pixel-ring coupling and latitude dependence of CMB temperatures,we find notable systematic devia- tion from CMB Gaussianity in released Wilkinson Microwave Anisotropy Probe(WMAP)*** detected deviation cannot be explained by the best-fit LCDM cosmological model at a confidence level above 99%and cannot be ignored for a precision cosmology study.

关键词： cosmology cosmic microwave background methods data analysis