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| 1 | Spatial heterogeneity of the driving forces of cropland change in China显示文摘By using digital satellite remote sensing data acquired in 1987―1989 and 1999―2000 and GIS combined with the natural and socio-economic data, this paper drew an integrated zonation of the cropland change and its driving forces in China. The results indicated that the cropland change in the study period was constrained by geographical factors and driven by cli-mate change as well as socio-economic system. Moreover, the regional differences of the drivers for cropland change were significant. In the midwest of China, natural condition changes and geographical background were the main constraints and drivers, while in Eastern China, social and economic changes and economic policies were the main driving forces. The cropland loss was nationwide. The dominant factors to cause this decrease included buildup of developing area to attract foreign capital and technologies, changes of industry structure due to urban in-fluence, the change of employment notions thanks to living standard improvement, rapid ur-banization due to the expansion of cities and towns, the diminished farming net income partly because of the global warming effects, and the rapid economic growth stimulated by the con-venient transportation system. These factors interact and interdepend with each other to cause the cropland loss in China recently. The reasons for the increase of cropland were primarily the cultivation and deforestation by the farmers who want to increase income. This study on the mechnism of LUCC relied on the cropland change integrated classification considering the natural or human factors both inside and outside the region, which provides a new approach to study the integrated regionalization and LUCC mechanism. | LIU Xuhua1,2, WANG Jinfeng1, LIU Mingliang4,1 & MENG Bin1,2,3 1. Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China 2. Graduate School of the Chinese Academy of Sciences, Beijing 100039, China 3. College of Arts and Sciences of Beijing Union University, Beijing 100083, China 4. School of Forestry and Wildlife Sciences, Auburn University, Auburn, Alabama, AL36849, USA | 2005 | Science China Earth Sciences2005，48，12： | 13 |
| 2 | A LOOP DRAWBEAD RESTRAINING FORCE MODEL IN SHEET METAL DEEP DRAWING PROCESS显示文摘In sheet metal forming, drawbeads are often used to control uneven material flow which may cause defects such as wrinkles, fracture, surface distortion and springback. Appropriate setting and adjusting the drawbead force is one of the most important pa- rameters in sheet metal forming process control. This paper derives the model of loop drawbead restraining force (DBRF) using plastic forming theory, and gives the min imum blankholding force. Experiments are carried out to verify the proposed DBRF model. The good agreement between the calculated values and experiments data justi- fies the proposed loop drawbead restraining force model. | Y.J. Luo, S.P. Li, J.F. Zheng, D.N. He, Y.Q. Zhang, J.L. Cheng and J. Y. Jiang 1)National Mold & Die CAD Engineering Research Center, Shanghai 200030, China 2)Shanghai Volkswagen Automotive Company Ltd.(SVM), Shanghai 201805, China | 2001 | Acta Metallurgica Sinica(English Letters)2001，14，5： | 11 |
| 3 | The Effect of Tide on the Global Climate Change显示文摘The differential rotation between the solid and fluid spheres caused by tidal force could explain the 1500 to 1800-year cycle of the world's temperature. Strong tide increases the vertical and horizontal mixing of water in the oceans, drawing the cold Pacific water from the depths to the surface and the warm water from the west to the east, where it cools or warms the atmosphere above, absorbs or releases CO2 to decrease or increase greenhouse effect and to make La Nina or El Nino occur in the global. The moon's declination and obliquity of the ecliptic affect the tidal intensity. The exchange of tidal energy and tide-generating force caused by the sun, moon and major planets makes the earth's layers rotate in different speeds. The differenti-al rotation between solid and fluid of the earth is the basic reason for El Nino and global climate change. | YANG Xuexiang, CHEN Zhen and CHEN Dianyou( College of Ceo - exploration Science and Technology, Jilin University, Changchun 130026, P. R. China)Qiao Qiyuan(National Astronomical Observatory, Chinese Academy of Science, Beijing 100012, P. R. China) | 2002 | Global Geology2002，7，1： | 7 |
| 4 | AN IN SITU SURFACE COMPOSITE AND GRADIENT MATERIAL OF Al-Si ALLOY PRODUCED BY ELECTROMAGNETIC FORCE显示文摘Because of the different conductivities between the primary phase (low electric conduc tivity) and the metal melt, electromagnetic force scarcely acts on the primary phase. Thus, an electromagnetic repulsive force applied by the metal melt exerts on the pri mary phase when the movement of the melt in the direction of electromagnetic force is limited. As a result, the repulsive force exerts on the primary phase to push them to move in the direction opposite to that of the electromagnetic force when the metal melt with primary phase solidifies under an electromagnetic force field. Based on this, a new method for production of in situ surface composite and gradient material by electromagnetic force is proposed. An in situ primary Si reinforced surface composite of Al-15wt%Si alloy and gradient material of Al-l9wt%Si alloy were produced by this method. The microhardness of the primary Si is HV1320. The reinforced phase size is in the range from 40μm to 100μm. The wear resistance of Al-Si alloy gradient material can be more greatly increased than that of their matrix material. | Z.M. Xu, T.X. Li, Z.L. Zhu and Y.H. Zhou School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200030, China | 2001 | Acta Metallurgica Sinica(English Letters)2001，14，5： | 3 |
| 5 | COUPLED NUMERICAL SIMULATION OF STEEL FLOW AND SOLIDIFICATION IN SOFT-CONTACT BILLET MOLD显示文摘A coupled model including electromagnetic field, fluid dynamic, heat transfer and so-lidification, is developed and applied to the numerical simulation of steel flow andsolidification in a 100mm× 100mm soft-contact mold. In this study, the 3D finite dif-ference method and n, on-staggered grid system for fluid flow with body fitted coordinatewere employed. Numerical results show that the electromagnetic force mainly affectsthe steel flow at upper part of mold, especially in the vicinity of meniscus. There existupward flows covering the surfaces of the billet due to the concentration of electro-magnetic force on the upper part of the billet. This flows join together and form adownward flow near the SEN, so a distinct circulating flow zone is formed at upperpart of mold. After applying electromagnetic force, the steel velocity is improved andthe temperature is raised. The strong stirring of electromagnetic force on liquid steelmakes the kinetic energy on free surface increase. It is clearly seen that the solidifi-cation start point shifts downward in soft contact mold. As a result, the initial shellthickness gets thin and the initial solidification shell length is shortened. | A.Y. Deng and J.C. HeKey Laboratory for Electromagnetic Processing of Materials, Ministry of Education, Northeastern University, Shenyang 110004, China | 2002 | Acta Metallurgica Sinica(English Letters)2002，15，5： | 2 |
| 6 | Numerical investigation of solitary wave action on tworectangular boxes with a narrow gap显示文摘Based on the time-domain higher-order boundary element method(HOBEM), a two-dimensional numerical wave flume is developed to investigate solitary wave interaction with two rectangular boxes with a narrow gap.In the numerical model, the fully nonlinear boundary conditions are satisfied on the free surface, the mixed Eulerian-Lagrangian method is adopted to track the transient water surface and the fourth-order Runga-Kutta method is used to predict the velocity potential and wave elevation on the free surface. The acceleration potential technique is used to compute the transient wave forces along the wetted object surface. A piston-type wavemaker is used to generate solitary waves. The proposed model is validated by comparing the simulated wave run-up and the wave loads with the published experimental and numerical results of the reflection of a solitary wave from a vertical wall. Then, numerical experiments are performed to study the effects of the narrow gap and the size of each box on the wave run-ups at the two sides of the two-box system and in the narrow gap between two boxes, and the wave loads on the two boxes. The interaction between double solitary waves with a time interval between them with a two-box system is also investigated. | NING Dezhi SU Xiaojie ZHAO Ming | 2016 | Acta Oceanologica Sinica2016，35，12： | 2 |
| 7 | 圆管大直径外翻边孔加工工艺设计与翻边力计算(英文)显示文摘针对现有圆管翻边工艺无法加工与圆管直径接近的外翻边孔的缺陷,提出了一种新的加工工艺方法。考虑新工艺的变形特点、加工硬化特性以及变形区的材料厚度的变化情况,推导出针对圆管翻边的翻边力计算公式。Abaqus仿真数据表明:相对于板材翻边力计算公式,本文的翻边力计算公式更加精确。 | 吴磊 刘彬 丁立刚 | 2015 | 机床与液压2015，43，18： | 1 |
| 8 | Research on the Earth system multi-body force system dynamical model显示文摘This paper presents an overview of the binding force and freedom force of Earth system, and describes force moment to point and line and force system in the Earth system. It introduces the force theory of the Earth system multi-body force system from special or equivalent force system of Earth system mechanics, general force and no-power force of Earth system. Finally it describes the force and moment of nodes of Earth system and provides basic model for the research of the Earth system multi-body dynamics. | CHEN Xiaofei, BI Siwen, WU Fei & DONG Qianlin State Key Laboratory of Remote Sensing Science, Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University, Beijing 100101, China Laboratory of 3D Information Access and Application of Capital Normal University, Beijing 100037, China | 2006 | Science China(Technological Sciences)2006，49，z2： | 0 |
| 9 | An Earth multi-body system elasticity and plasticity dynamics model显示文摘Research on the elasticity and plasticity dynamics of the Earth multi-body system, including the Earth multi-body system stratum-block's equivalent inertia force system and generalized inertia force, the Earth multi-body system stratum-block's equivalent inertia force system expressed with partial velocity and partial palstance, and Earth multi-body system generalized inertia force expressed with partial velocity and partial palstance. This research provides a theoretical foundation for further investigation of Earth multi-body dynamics. | ZHANG Qingxian, BI Siwen & GONG Huili Education Ministry Key Laboratory of Three-Dimensional Information Extraction and Application, Capital Normal University, Beijing 100037, China State Key Laboratory of Remote Sensing Science, IRSA, Chinese Academy of Sciences, Beijing 100101, China | 2006 | Science China(Technological Sciences)2006，49，z2： | 0 |
| 10 | Numerical Simulation of Electromagnetic Force in Double-Sided Arc Welding Process显示文摘Up till now, most of the researchers believe that there are four kinds of forces in the weld pool convection, they aresurface tension, electromagnetic force, buoyancy and gas shear stress. So electromagnetic force is very important,especially when large current is applied. In most of previous models, the electromagnetic force is calculated analytically,in which only the axial component of current is considered. Actually the radial component of current has thesame effect, and may be advanced in some locations. In double-sided arc welding process, instead of the earthclamp, another torch is placed on the opposite side; the current will go from one torch, through the weld zone,to another torch. In this case, the current is more concentrated in the weld zone; the electromagnetic force willhave significant effect compared with conventional welding process. In this paper, a new method of numericalcalculation for electromagnetic force is developed, in which both axial and radial components are considered. And asan example, the distribution of electromagnetic force in double-sided arc welding is calculated. It demonstrates thatthis new method could give more accurate simulation of electromagnetic force, and is close to the actual process. | Hongming GAO Lin WU Honggang DONG | 2003 | Journal of Materials Science & Technology2003，19，z1： | 0 |
| 11 | A Neo Explanation of the'Mass-Velocity Relation显示文摘ANeoExplanationofthe"Mass-VelocityRelation"XuShaozhi;andXuXiangqun(BeijingControlDeviceResearchInstitute,P.O.Box3913,Beijing1... | Xu Shaozhi and Xu Xiangqun (Beijing Control Device Research Institute, P.O. Box 3913, Beijing 100854, P.R. China) | 1994 | Journal of Systems Engineering and Electronics1994，5，2： | 0 |
| 12 | A STUDY OF HIGH LOFT NONWOVEN FABRICS USING POWDER BONDING TECHNOLOGY显示文摘In this paper, two types of high loft nonwoven fabrics have been constructed in the laboratory apparatus made by ourselves with different binders (polyamide and polyethylene powder) and varying binder contents (10%, 20%, 30% and 40%). The tensile and compression properties of these nonwoven fabrics were tested. It was found that one can reduce powder binder content to increase loft and softness of nonwoven fabrics, but it has to sacrifice its tensile strength. Adhesion force between binder and single fibre was also explored. The experiments showed that the adhesion force at the interface between binder and fibre depends on the fibre variety, the fibre surface morphology, heating temperature and heating time etc.. | 储才元 严灏景 | 1994 | Journal of China Textile University(English Edition)1994，11，1： | 0 |
| 13 | Effect of induced shielding current transmission in longitudinal direction on levitation force of melt grown single-domain YBa_2Cu_3O_(7-x) cylindrical superconductor显示文摘A novel layer deletion method is used to experimentally investigate the effect of induced shielding current transmission (ISCT) in the longitudinal direction on the levitation force of a single-domain YBa2Cu3O7-x (YBCO) cylindrical superconductor (f30? mm). In the experiment the sample was gradually sliced into two equal sheets, at the middle height along a diameter with 5 mm every step. The experimental results show that the levitation force is closely related with the ISCT in the longitudinal direction. Any layer deletion, even a small piece of layer deletion can reduce the levitation force of the sample. After the whole layer was deleted the levitation force can diminish about 50%. It is also found that the levitation force is directly proportional to the effective factor of surface area, which is equal to the top surface area divided by the total surface area parallel to the top surface of the sample. | R. Nicolsky R. de Andrade Jr | 2004 | Science China(Physics,Mechanics & Astronomy)2004，47，2： | 0 |
| 14 | Maxwell-Chern-Simons Casimir Force Between Perfectly Conducting Parallel Lines显示文摘Using Feynman path integral method we calculate the Casimir force of Maxwell Chern Simons Abelian gauge field between perfectly conducting parallel lines. | ZHENG Tai-Yu ZHENG Li LI Chang-Song | 2001 | Communications in Theoretical Physics2001，，10： | 0 |
| 15 | The Kantorovich macro-or-mesoscopic refined solution for the heterogeneous functionally gradient material complex structure显示文摘This paper is a piece of research on the complex structure of functionally gradient mate-rials, which is an applicable triangular cantilever plate structure locally fixed and supported by its round revolving axis. Combined with the generalized Euler equation and the generalized boundary conditions, Kantorovich method and the principle of the two independent variables generalized calculus of variations are adopted to establish the bending governing equation of plates to work out the solution. In comparison with the previous work on the problem, this paper, taking into ac-count three generalized mechanical factors and FGM macro-or-mesoscopic heterogeneity, pro-poses a new concept of translating the issue of theoretical initial value into the problem of semi-analytical boundary value to obtain the refined solution and then researches the joint effect of grads stress fields. Thereby a refined version of Kantorovich macro-or-mesoscopic solution is de-veloped. | 李永 宋健 张志民 | 2003 | Science China(Technological Sciences)2003，46，1： | 0 |
| 16 | Instability of cylinder wake under open-loop active control显示文摘Instability of a wake controlled by a streamwise Lorentz force is investigated through a Floquet stability analysis. The streamwise Lorentz force, which is a two-dimensional control input created by an electromagnetic actuator located on the cylinder surface,adjusts the base flow to affect the three-dimensional wake instability and achieve wake stabilization and transition delay. The instability mode at a Reynolds number Re = 300 can be transformed from B to A with N = 1.0, where N is an interaction number representing the strength of the Lorentz force relative to the inertial force in the fluid. The wake flow is Floquet stable when N increases to 1.3. The spanwise perturbation wavelengths are 3.926 D and 0.822 D in the modes A and B, respectively, where D is the cylinder diameter. In addition, the oscillating amplitudes of drag and lift are reduced with the increase in the interaction number. Particle tracing is used to explore the essential physical mechanism for mode transformation. The path lines show that suppression of flow separation hinders the fluid deformation and rotation, leading to the decrease in elliptic and hyperbolic instability regions, which is the material cause of mode transformation.All of the results indicate that wake stabilization and transition delay can be achieved under open-loop active control via the streamwise Lorentz force. | Yadong HUANG Benmou ZHOU Zhaolie TANG | 2017 | Applied Mathematics and Mechanics(English Edition)2017，38，3： | 0 |
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