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A new heuristic algorithm for the circular packing problem with equilibrium constraints

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Science china(information Sciences) 2011年第8期54卷 1572-1584页

作者： LIU JingFa 1,2,LI Gang 3.& GENG HuanTong 1 1 School of Computer and Software,Nanjing university of information Science & Technology,Nanjing 21004.,china 2 Network information center,Nanjing university of information Science & Technology, Nanjing 21004.,china 3.School of Mathematics and Physics,Nanjing university of information Science & Technology,Nanjing 21004.,china School of Computer and Software Nanjing University of Information Science & Technology Network information center Nanjing University of Information Science & Technology School of Mathematics and Physics Nanjing University of Information Science & Tec

The circular packing problem with equilibrium constraints is an optimization problem about simplified satellite module layout design.A heuristic algorithm based on tabu search is put forward for solving this *** algorithm begins from a random initial configuration and applies the gradient method with an adaptive step length to search for the minimum energy *** jump out of the local minima and avoid the search doing repeated work,the algorithm adopts the strategy of tabu *** the process of tabu search,we improve the traditional neighboring solutions,tabu objects and the acceptance criteria of the current solution *** test two sets of benchmarks consisting of 11 representative instances from the current *** numerical results show that the proposed algorithm breaks the records in seven out of 11 instances,and obtains the optimal solutions for the other four instances.

关键词： equilibrium constraints packing problem heuristic algorithm tabu search layout optimization

Dynamics of DNA in vitro evolution

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Progress in Natural Science:Materials International 2009年第2期19卷 137-144页

作者： Xiaojing Yang 1,Xili Liu 1,Chunbo Lou,Qi Ouyang center for Theoretical Biology,School of Physics,peking university,Beijing {3.,{4. center for Theoretical Biology School of Physics Peking University Beijing 100871 China

In vitro evolution has become a very important research area in recent years. From a practical point of view,it provides a powerful and reliable tool for engineering functional molecules (DNA,RNA or proteins) in reasonably short periods of time. From a theoretical point of view,since in vitro evolution is analogous to natural evolution in many respects,the study of the dynamic details of in vitro evolution may provide some instructive insights into the process of evolution. In this review,we summarize current theoretical and exper-imental studies,including several efforts made by our group,on the dynamics of DNA in vitro evolution.

关键词： DNA-TF interaction DNA in vitro evolution Natural evolution Crossover

Rapid Fabrication of CdS Nanocrystals with Well Mesoporous Structure Under Ultrasound Irradiation at Room Temperature

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Chemical Research in Chinese Universities 2012年第1期28卷 124-128页

作者： YU Chang-lin1, ZHOU Wan-qin2,3. YU Jim-my4. YANG Jian-gao5 and FAN Qi-zhe1 1. School of Metallurgy and Chemical Engineering, 2. School of information Engineering, Jiangxi university of Science and Technology, Ganzhou 3.1000, P. R.{4. 3. Fujian Provincial Key Laboratory of Photocatalysis-State Key Laboratory Breeding Base, Fuzhou university, Fuzhou 3.0002, P. R.{4. 4. Department of Chemistry, center of Novel Functional Molecules, and Environmental Science Programme, Chinese university of Hong Kong, Shatin, New Territories, Hong Kong, P. R.{4. 5. Engineering Research center of High-efficiency Development and Application Technology of Tungsten Resources, Ministry of Education, Jiangxi university of Science and Technology, Ganzhou 3.1000, P. R.{4. School of Metallurgy and Chemical Engineering Jiangxi University of Science and Technology Ganzhou 341000 School of information Engineering Jiangxi University of Science and Technology Fujian Provincial Key Laboratory of Photocatalysis-State Key Laboratory Breeding Base Ganzhou 341000 Department of Chemistry Center of Novel Functional Molecules and Environmental Science Programme Chinese University of Hong Kong Hong Kong Engineering Research center of High-efficiency Development and Application Technology of Tungsten Resources Ministry of Education Jiangxi University of Science and Technology Ganzhou 341000

Sphere-like mesoporous CdS nanocrystals with high crystallinity and big surface area were successfully fabricated by ultrasound irradiation at room temperature. The as-synthesized CdS with and without ultrasound irra diation was investigated by the characterizations of X-ray diffraction（XRD）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, and Brunauer-Emmett-Teller（BET） surface areas. The photocatalytic acti vity of the CdS was evaluated by photocatalytic degradation of methyl orange under visible light（λ〉4.0 nm） irradia tion. A possible mechanism for the formation of the CdS nanocrystals with mesoporous structure under ultrasound irradiation was proposed. The results show that both the template role of the triblock copolymer of P123.and the effect of ultrasound-induced aggregation are mainly responsible for the formation of mesoporous structure. On the other hand, the energy generated from acoustic cavitation can effectively accelerate the crystallization process of the amorphous CdS.

关键词： CdS Crystallinity Mesoporous structure Ultrasound-induced aggregation

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, china 2 Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 23.03., china 3.School of Earth and Space Science,{3., Beijing 100871, china 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

Palaeorunoff estimations achieved from palaeoclimatic information for the southwest part of the North china Plain: an attempt to apply a climatological approach to palaeohydrology

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Journal of Environmental Sciences 2000年第3期12卷 330-336页

作者： WANG Hong\|ya, XIE Qiang (Department of Urban and Environmental Sciences, peking university,Beijing 100871, china) 北京大学北京 1 0 0 871

Palaeoclimatic scenario projecting annual temperature and annual precipitation is firstly formalized with data available and speculations for the southwest part of the North china Plain (3.— 3.°N, 115—119°E) during the last 25000 years. Then, with three regression equations relating annual runoff to annual precipitation and derived with data of modern hydrological and meteorological records, values of annual runoff are calculated in terms of the corresponding values of annual precipitation from this palaeoclimatic scenario for this region during this temporal interval. These results indicate that runoff is the most during 8000—3.00 a B.P. and the least during 25000—12000 a B.P.; runoff occurring during 12000—8000 a B.P. and during 3.00—0 a B.P. is less than the one occurring during 8000—3.00 a B.P. and more than the one occurring during 25000—12000 a B.P.; and the runoff occurring during 25000—12000 a B.P., 12000—8000 a B.P., and 3.00—0 a B.P. is respectively 4.1} 4. and 66 percent of the one occurring during 8000—3.00 a B.P. Values of bankfull discharge for palaeochannels of the Yellow River flowing in this region during the same interval are calculated from available estimates of slope of stream bed of these palaeochannels with a regression equation relating bankfull discharge to slope of stream bed and ratios of bankfull discharge are further calculated from these values for different groups of palaeochannel formed during different time spans embraced in this interval. To conduct a cross check, these values and ratios of bankfull discharge are compared to the corresponding values and ratios of runoff occurring during roughly the same time spans. The same direction and similar relative magnitude of changes of the surface water occurring in this region during the last 25000 years are indicated by these comparisons.

关键词： palaeorunoff the southwest part of the North china Plain palaeoclimate

New numerical algorithms in SUPER CE/SE and their applications in explosion mechanics

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Science china(Physics,Mechanics & Astronomy) 2010年第9期53卷 237-243页

作者： WANG Gang1,2,WANG JingTao1 & LIU KaiXin1,3.1 LTCS and College of Engineering,peking university,Beijing 100871,{3. 2 LHD,Institute of Mechanics,Chinese Academy of Sciences,Beijing 100190,{3. 3.center for Applied Physics and Technology,peking university,Beijing 100871,{3. peking university LTCS and College of Engineering Beijing China (GRID:grid.11135.37) (ISNI:***) Chinese Academy of Sciences LHD Institute of Mechanics Beijing China (GRID:grid.9227.e) (ISNI:***) peking university LTCS and College of Engineering Beijing China (GRID:grid.11135.37) (ISNI:***) peking university LTCS and College of Engineering Beijing China (GRID:grid.11135.37) (ISNI:***) peking university Center for Applied Physics and Technology Beijing China (GRID:grid.11135.37) (ISNI:***)

The new numerical algorithms in SUPER/CESE and their applications in explosion mechanics are studied. The researched al-gorithms and models include an improved CE/SE (space-time Conservation Element and Solution Element) method,a local hybrid particle level set method,three chemical reaction models and a two-fluid model. Problems of shock wave reflection over wedges,explosive welding,cellular structure of gaseous detonations and two-phase detonations in the gas-droplet system are simulated by using the above-mentioned algorithms and models. The numerical results reveal that the adopted algorithms have many advantages such as high numerical accuracy,wide application field and good compatibility. The numerical algo-rithms presented in this paper may be applied to the numerical research of explosion mechanics.

关键词： new algorithm SUPER CE/SE numerical simulation explosion mechanics

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AutoProc: An automatic proactive replication scheme for P2P storage

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Science china(information Sciences) 2011年第6期54卷 1151-1160页

作者： YANG Zhi & DAI YaFei Computer Science Department, peking university, Beijing 100871, china Computer Science Department Peking University

Due to the prevalence of peer departures, P2P storage systems need to constantly generate replicas for high durability. However, few existing systems are able to select the right replication rate that balances replication cost and durability, e.g., minimizing replication cost without threatening the durability target. In this paper, we propose a method called AutoProc to automate the replication process in P2P storage systems. AutoProc employs two key techniques to enable cost-effective replication: correctly adapting replication rate with a reliability model, and replicating objects at the right order with a reliability indicator. Extensive simulations based on the real system failure trace show that AutoProc achieves the near-optimal performance.

关键词： P2P storage churn durability fault tolerance proactive replication resource usage

A SYSTEM DYNAMICS APPROACH FOR SUSTAINABLE DEVELOPMENT IN THE MIYUN RESERVOIR AREA, china

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Chinese Geographical Science 2002年第2期12卷 157-165页

作者： SUN Yan feng,GUO Huai cheng,QU Guang yi(center for Environmental Sciences,peking university,Beijing {3.,P. R.{4.) center for Environmental Sciences Peking University Beijing 100871 P. R. China

Miyun Reservoir was designated as the water source of Beijing City in 1982. Since that time, socio economic development in Miyun Area has been slowing due to the restriction of severe environmental standards. More and more attention from the public and government has been paid to the regional sustainable development. And an effective planning for the local society management system is urgently desired. In this study, a regional sustainable development system dynamics model, named MiyunSD, is developed for supporting this planning task. MiyunSD consists of dynamic simulation models that explicitly consider information feedback that governs interactions in the system. Such models are capable of simulating the system′s behavior and predicting its developing situation of the future. For the study case, interactions among a number of system components within a time frame of fifteen years are examined dynamically. Three planning alternatives are carefully considered. The base run is based on an assumption that the existing pattern of human activities will prevail in the entire planning horizon, and the other alternatives are based on previous and present planning studies. The different alternatives will get different system′s environmental and socio economic results. Through analyzing these dynamic results, local authorities may find an optimal way to realize the objectives that the regional environment will be well protected and at the same time the economy will be rapidly developed.

关键词： Miyun reservoir sustainable development model policy management system dynamics

Latest cosmological constraints on Cardassian expansion models including the updated gamma-ray bursts

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Research in Astronomy and Astrophysics 2011年第9期11卷 1019-1030页

作者： Nan Liang Pu-Xun Wu Zong-Hong Zhu Department of Astronomy Beijing Normal University Beijing 100875 China center for High Energy Physics Peking University Beijing 100871 China center of Nonlinear Science and Department of Physics Ningbo University Ningbo 315211 China

We constrain the Cardassian expansion models from the latest observa- tions, including the updated Gamma-ray bursts （GRBs）, which are calibrated using a cosmology independent method from the Union2 compilation of type Ia supernovae （SNe Ia）. By combining the GRB data with the joint observations from the Union2 SNe Ia set, along with the results from the Cosmic Microwave Background radia- tion observation from the seven-year Wilkinson Microwave Anisotropy Probe and the baryonic acoustic oscillation observation galaxy sample from the spectroscopic Sloan Digital Sky Survey Data Release. we find significant constraints on the model oarameters of the original Cardassian model ΩM0=0.282-0.014.0.015,n=0.03.0.05^＋0.05 and n=-0.16-3.26^＋0.25,β=0.76-0.58^＋0.3. of the modified polytropic Cardassian model, which are consistent with the ACDM model in a l-or confidence region. From the reconstruction of the deceleration parameter q（z） in Cardassian models, we obtain the transition redshift ZT = 0.73.± 0.04.for the original Cardassian model and ZT = 0.68 ± 0.04.for the modified polytropic Cardassian model.

关键词： gamma-rays bursts -- cosmology cosmological parameters