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Ratchet transport of overdamped particles in superimposed driven lattices

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Chinese Physics B 2019年第4期28卷 108-112页

作者： Shu-Na Huang Wei-Jing Zhu Xiao-Qun Huang Bao-Quan Ai Feng-Guo Li Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials School of Physics and Telecommunication EngineeringSouth China Normal University

Ratchet transport of overdamped particles is investigated in superimposed driven lattices using Langevin dynamics simulations. It is found that noise can strongly affect the transport of the particles. When lattices driving dominates the transport, the noise acts as a disturbance of the directed transport and slows down the average velocity of the *** the driving phase has less impact on particle transport, Gaussian white noise can play a positive role. By simply modulating these two parameters, we can control efficiency and the direction of the directed currents.

关键词： Gaussian white noise superimposed driven lattices rectification

Efficient and accurate online estimation algorithm for zero-effort-miss and time-to-go based on data driven method

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Chinese Journal of Aeronautics 2019年第10期32卷 2311-2323页

作者： Hongxia LI Huijie LI Yuanli CAI School of Electronic and Information Engineering Xi’an Jiaotong University

This paper introduces a novel and efficient algorithm for online estimation of zero-effortmiss and time-to-go based on data driven *** missile-target separations are utilized to construct the estimation models,and a practical Fisher fusion algorithm is derived to acquire the estimates with high accuracy and computational ***,the two parameters can be online estimated at a particular ***,the kinematics equations of the missile-target engagement are independent,and assumptions of the missile guidance system dynamics and behaviors of the missile and target are completely out of ***,the effectiveness and applicability are explicitly verified through various simulation scenarios.

关键词： Data driven Missile-target separations Online estimation Time-to-go Zero-effort-miss

A looped heat-driven thermoacoustic refrigeration system with direct-coupling configuration for room temperature cooling

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Science Bulletin 2019年第1期64卷 8-10页

作者： Huizhi Wang Limin Zhang Guoyao Yu Jianying Hu Ercang Luo Ying Ma Chao Jiang Xianxian Liu Key Laboratory of Cryogenics Technical Institute of Physics and Chemistry Chinese Academy of Sciences School of Engineering Science University of Chinese Academy of Sciences School of Future Technology University of Chinese Academy of Sciences

Heat-driven thermoacoustic refrigeration has drawn extensive concern in the past decades due to its advantages of high reliability and external heat-driven *** such a system,heat can be firstly converted into acoustic power and then the acoustical power drives a refrigerator to generate cooling effect without any moving mechanical *** far,most of researches on heat-driven thermoacoustic refrigeration have focused on cryo- genic application,such as natural gas liquefaction [1,2].In addition, heat-driven thermoacoustic refrigeration also plays important roles in recovering waste heat and provides an environment- friendly alternative to the current abso'rption chiller especially in the small-scale power range [3-7].However,two main obstacles to use the thermoacoustic technology in practice are its relatively low cooling capacity and low cooling *** the two-loop configuration proposed by Luo et al.[5]or the configuration of a one-unit refrigerator driven by a three-unit engine brought forward by Kees [6],they both suffer from phase-shifting tube and mismatch between the thermoacoustic engine (TAE)and thermoacoustic refrigerator (TAR).

关键词： Direct coupling Refrigeration system Thermoacoustic refrigeration driven by heat

Upwind Compact Method and Direct Numerical Simulation of driven Flow in a Square Cavity*

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Science China Mathematics 1993年第11期36卷 1347-1357页

作者：刘宏付德熏马延文 LNM Institute of Mechanics Academia Sinica Beijing 100080 PRC

A high-order accurate finite-difference scheme, the upwind compact method, is proposed. The 2-D unsteady incompressible Navier-Stokes equations are sOlved in primitive variables. The nonlinear convection terms in the governing equations are approximated by using upwind biased compact difference, and other spatial derivative terms are discretized by using the fourth-order compact difference. The upwind compact method is used to solve the driven flow in a square cavity. Solutions are obtained for Reynolds numbers as high as 10000. When Re≤5000, the results agree well with those in literature. When Re=7500 and Re=10000, there is no convergence to a steady laminar solution, and the flow becomes unsteady and periodic.

关键词： numerical simulation upwind compact scheme unsteady separated vortex driven flow in a cavity.

Magnetically driven Superhydrophobic Polyurethane Sponge for High Efficiency Oil/Water Mixtures Separation

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Journal of Bionic Engineering 2019年第1期16卷 38-46页

作者： Xuemei Zhang Feng Fu Xiaoming Gao Xiufang Hou Shaanxi Key Laboratory of Chemical Reaction Engineering Department of Chemistry and Chemical EngineeringYan'an UniversityYan'an 716000China

Magnetically driven super-hydrophobic materials were prepared by Fe3O4 nanoparticles and stearic acid,which were deposited on the surface of polyurethane *** presence of the Fe3O4 nanoparticles makes the sponge have the magnetic,and the micro-nano hierarchical structure and hydrophobic functional groups lead to the sponge have excellent *** as-prepared sponge exhibited excellent absorption capacities for various oils and organic solvents ranging from 23.8 times to 86.7 times of its own ***,the oil separation capacities still keep a high value after 50 cycles of squeezing the saturated absorbed as-prepared *** of these satisfactory properties make the as-prepared sponge as a candidate of ideal absorbents for oily industrial wastewater and oil spills in oceans.

关键词： superhydrophobic/superoleophilic materials polyurethane sponge magnetic driven oil-water separation continuous separation

Numerical study of asymmetric driven reconnection at dayside magnetopause

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Science China(Technological Sciences) 2000年第2期43卷 129-145页

作者：金曙平沈俊太郝蕾胡先鹏 1. Department of Earth and Space Science University of Science and Technology of China 230026 Hefei China 2. Advanced Center for Earth Science and Astronomy University of Science and Technology of China Third World Academy of Science 230026 Hefei China

A two-dimensional compressible MHD code has been used to numerically study the asymmetric driven reconnection processes in the vicinity of the magnetopause. The initial magnetic field configuration is assumed to be in a mechanical equilibrium state. The cases with identical temperatures (T m0/T s0=1.0) and four different ratios of magnetic field strength (Q=B m0/B s0=1.0, 1.5, 2.0, 2.5), and the case withT m0/T s0=2.0 andQ=1.5 are investigated (B m0,T m0 andB s0,T s0 are the initial magnetic strength and temperature outside the current sheet on the magnetosphere and the magnetosheath, respectively). When the magnetic field on the magnetosheath side is set as southward, a recurrent formation of multiple magnetic bubbles with various scales occurs under the action of the inward plasma flow imposed at the left and right boundaries. In the simulation, some bubbles coalesce into a bigger one and then it is convected out of the simulation domain; the others are convected through the top boundary all alone. Thus, the plasmoid events with different scales and different time intervals take place intermittently and the impulsive features of magnetic reconnection are clearly shown. The multiple magnetic islands are all high-temperature and large-density regions in comparison with the ambient environment. The bipolar signatures or fluctuant variations of normal magnetic field component are generated by the formation of multiple magnetic islands. This result is similar to the FTEs signature.

关键词： compressible MHD code asymmetric driven reconnection dayside magnetopause.

Research and Progress of Service driven Optical Switching Network in China

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China Communications 2008年第1期5卷 9-21页

作者： Wang, Hongxiang Ji, Yuefeng Beijing Univ Posts & Telecommun Sch Telecommun Engn Key Lab Opt Commun & Lightwave Technol Minist EducAcad Comm Beijing Peoples R China

National R&D activities on optical switching networkare introduced. Optical switching network testbedswere established in China including 3T-net andOBS ring and mesh network test-bed with the supportof national '863' ... 详细信息

关键词： optical communications service driven optical network optical circuit switching optical burst switching optical packet switching test-bed

Distributions of the high temperature and the high pressure inside a single acoustically driven bubble

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Science China Mathematics 2002年第7期45卷 926-936页

作者：应崇福安宇 1. Institute of Acoustics Chinese Academy of Sciences 100080 Beijing China 2. Physics Department Tsinghua University 100084 Beijing hina

The physical circumstances inside an acoustically driven single gas bubble in water has been intensively explored during the past few years. Starting from the results obtained for a typical case in a well known early paper (Wu, C. C., Roberts, P. H., Phys. Rev. Lett., 1993, 70(22): 3424) and introducing successively several corrections to the physical model, this paper computes in corresponding order the temporal and spatial distributions of significant physical parameters, including the temperature and the pressure, in the bubble around the moment of the bubble's violent collapse, until expectations in consistence with the present points of view are procured. For the peak temperature our results agree with the prevailing belief that in a typical stable single bubble it is of the order of ten thousand degrees.

关键词： acoustically driven cavitation, single bubble, interior temperature distribution, interior pressure distribution.

Revisiting the Outsiders: Innovative Recruitment of a Marijuana User Network via Web-Based Respondent driven Sampling

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Social Networking 2014年第1期3卷 19-31页

作者： Seth S. Crawford Department of Sociology School of Public Policy Oregon State University Corvallis USA

This study uses an innovative, network-based recruitment strategy (non-monetary, web-based respondent driven sampling) to gather a sample of il/legal marijuana users. Network-driven effects amongst marijuana users are examined to test the explanatory validity of several theories of social deviance. The study finds that respondent driven sampling techniques lack effectiveness without primary monetary incentives, even when meaningful secondary incentives are utilized. Additionally, the study suggests that marijuana user networks exhibit strong homophilic attachment tendencies.

关键词： Marijuana Respondent driven Sampling Social Network Analysis Methods