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General and efficient parallel approach of finite element-boundary integral-multilevel fast multipole algorithm

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Journal of Systems Engineering and Electronics 2008年第2期19卷 207-212页

作者： pan Xiaomin Sheng Xinqing Center for Electromagnetics Simulation School of Information Science and Technology Beijing Inst. of Technology Beijing 100081 P. R. China

A general and efficient parallel approach is proposed for the first time to parallelize the hybrid finiteelement-boundary-integral-multi-level fast multipole algorithm （FE-BI-MLFMA）. Among many algorithms of FE-BI-MLFMA, the decomposition algorithm （DA） is chosen as a basis for the parallelization of FE-BI-MLFMA because of its distinct numerical characteristics suitable for parallelization. On the basis of the DA, the parallelization of FE-BI-MLFMA is carried out by employing the parallelized multi-frontal method for the matrix from the finiteelement method and the parallelized MLFMA for the matrix from the boundary integral method respectively. The programming and numerical experiments of the proposed parallel approach are carried out in the high perfor- mance computing platform CEMS-Liuhui. Numerical experiments demonstrate that FE-BI-MLFMA is efficiently parallelized and its computational capacity is greatly improved without losing accuracy, efficiency, and generality.

关键词： finite element-boundary integral-multilevel fast multipole algorithm parallelization.

New opportunities for ferroelectric deep-UV nonlinear optical crystals

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Science China Materials 2024年第3期67卷 1004-1005页

作者： Miriding Mutailipu Shilie pan Research Center for Crystal Materials Xinjiang Technical Institute of Physics and ChemistryChinese Academy of SciencesUrumqi 830011China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

Deep-ultraviolet(deep-UV)light with the wavelength below200 nm is one of the most crucial elements of both laser-driven industrial and scientific applications in recent years[1].DeepUV light has been produced using a variety of techniques,such as gas discharge lamps,synchrotron radiation,excimer lasers,free electron lasers,and nonlinear frequency conversion.

关键词： nonlinear optical ferroelectric

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Distributed sampling measurement method of network traffic in high-speed IPv6 networks

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Journal of Systems Engineering and Electronics 2007年第4期18卷 835-840页

作者： pan Qiao Pei Changxing State Key Lab. of Integrated Services Networks Xidian Univ. Xi'an 710071 P. R. China

With the advent of large-scale and high-speed IPv6 network technology, an effective multi-point traffic sampling is becoming a necessity. A distributed multi-point traffic sampling method that provides an accurate and efficient solution to measure IPv6 traffic is proposed. The proposed method is to sample IPv6 traffic based on the analysis of bit randomness of each byte in the packet header. It offers a way to consistently select the same subset of packets at each measurement point, which satisfies the requirement of the distributed multi-point measurement. Finally, using real IPv6 traffic traces, the conclusion that the sampled traffic data have a good uniformity that satisfies the requirement of sampling randomness and can correctly reflect the packet size distribution of full packet trace is proved.

关键词： network measurement traffic sampling IPv6 distributed measurement Shannon entropy

(Nd_(0.9)Dy_(0.1))_(16)Co_(5)Fe_(70)Nb_(2)B_(7) PERMANENT MAGNETIC ALLOY AND BEHAVIOUR OF Nb

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Transactions of Nonferrous Metals Society of China 1996年第1期6卷 67-71页

作者： pan Shuming pan Feng Ma Ruzhang General Research Institute of Non-ferrous Metals Beijing 100088 Beijing Tape Recorder Factory Beijing 100080 University of Science and Technology Beijing Beijing 100083

The magnetic properties of (Nd_(0.9)Dy_(0.1))_(16)Co_(5)Fe_(70)Nb_(2)B_(7) permanent magnetic alloy prepared by powder metallurgy are:Br=1.08T,_(1)H_(C)=1620kA/m,(BH)_(max)=208kJ/m^(3).The behaviour of Nb in this alloy was studied by joint methods of dynamic observation by high voltage electron microscope(HVEM)and Mossbauer *** Nb and Co substituting parts of Fe and adding a little Dy,practical magnetic alloy with excellent properties can be *** thermal stability of it is 80 ℃ higher than that of ternary Nd-Fe-13 *** study shows that adding Nb into Nd-Fe-B can make the intrinsic coercivity appear peak value at about Nb=2%(in mole fraction).Nb mainly enters into Nd-rich and B-rich phases,a little into Nd_(2)Fe_(14)B phase.

关键词： (Nd_(0.9)Dy_(0.1))_(16)Co_(5)Fe_(70)Nb_(2)B_(7) permanent magnetic alloy magnetic properties

Solving Low-Density Multiple Subset Sum Problems with SVP Oracle

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Journal of Systems Science & Complexity 2016年第1期29卷 228-242页

作者： pan Yanbin ZHANG Feng Key Laboratory of Mathematics Mechanization NCMISAcademy of Mathematics and Systems ScienceChinese Academy of Sciences

It is well known that almost all subset sum problems with density less than 0.9408… can be solved in polynomial time with an SVP oracle that can find a shortest vector in a special *** this paper,the authors show that a similar result holds for the k-multiple subset sum problem which has k subset sum problems with exactly the same ***,for the single subset sum problem(k=1),a modified lattice is introduced to make the proposed analysis much simpler and the bound for the success probability tighter than ***,some extended versions of the multiple subset sum problem are also considered.

关键词： Lattice low-density multiple modular subset sum problem multiple subset sum problem

Land-use induced changes in topsoil organic carbon stock of paddy fields using MODIS and TM/ETM analysis:A case study of Wujiang County,China

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Journal of Environmental Sciences 2008年第7期20卷 852-858页

作者： GAO, Jianfeng pan, Genxing JIANG, Xiaosan pan, Jianjun ZHUANG, Dafang Institute of Resources Ecosystem and Environment of Agriculture Nanjing Agricultural University Nanjing 210095 China Institute of Geographical Science and Natural Resources Chinese Academy of Sciences Beijing 100101 China

Topsoil soil organic carbon (SOC) that plays an important role in mitigating atmospheric carbon dioxide (CO_2) buildup is greatly affected by human *** evaluate the influence of land-use changes on SOC stocks in paddy soils,a new algorithm was developed by integrating MODIS (moderate resolution imaging spectral-radiometer) and TM/ETM data for timely monitoring the land-use change in Wujiang ***,the land-use class-maps derived from MODIS and TM/ETM analyses were further used to estima...

关键词： soil organic carbon (SOC) MODIS TM/ETM rice paddies land-use soil C sequestration

Prediction of the effective thermal conductivity of packed bed with micro-particles for thermochemical heat storage

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Science Bulletin 2017年第4期62卷 256-265页

作者： Zhihao pan Changying Zhao Key Laboratory of Power Machinery and Engineering of Ministry of Education School of Mechanical Engineering Shanghai Jiao Tong University Shanghai 200240 China

The heat transfer property of the powder bed greatly affects the performance of a thermochemical heat storage system. Therefore, an accurate evaluation of effective thermal conductivity （ETC） is a key for developing thermochemical heat storage systems. This paper focuses on the ETCs of commonly used por- ous thermochemical materials, such as MgOJMg（OH）2 and CaOJCa（OH）2 powders, as well as the corre- sponding composites with embedded metal foams. Random sphere-like particles packing （RSPP） method is proposed to reconstruct the microstructures of the powder and micro-scale generation method and computed tomography are adopted for the metal foams. Energy transport equations through porous media are solved by the lattice Boltzmann method （LBM） to obtain ETC. Results obtained using RSPP-LBM method agree with experimental data better than other existing methods. For thermochemical heat stor- age, the variation of ETC during chemical reactions is numerically predicted. Metal foam-embedded ther- rnochemical materials are also studied to evaluate the enhancing effects of the metal foams. Results show that ETC of the powders is dominated by the gas phase, whereas that of the metal foam composites is dominated by the metal Phase.

关键词： Thermochemical heat storageEffective thermal conductivity MgO CaO

Design and simulation of ex-range gliding wing of high altitude air-launched autonomous underwater vehicles based on SIMULINK

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Chinese Journal of Aeronautics 2013年第2期26卷 319-325页

作者： pan Changjun Guo Yingqing School of Power and Energy Northwestern Polytechnical University

High altitude air-launched autonomous underwater vehicle （AL-AUV） is a new anti-submarine field, which is designed on the Lockheed Martin＇s high altitude anti-submarine warfare weapons concept （HAAWC） and conducts the basic aerodynamic feasibility in a series of wind tunnel trials. The AL-AUV is composed of a traditional torpedo-like AUV, an additional ex-range gliding wings unit and a descending parachute unit. In order to accurately and conveniently investigate the dynamic and static characteristic of high altitude AL-AUV, a simulation platform is established based on MATLAB/SIMULINK and an AUV 6DOF （Degree of Freedom） dynamic model. Executing the simulation platform for different wing＇s parameters and initial fixing angle, a set of AUV gliding data is generated. Analyzing the recorded simulation result, the velocity and pitch characteristics of AL-AUV deployed at varying wing areas and initial setting angle, the optimal wing area is selected for specific AUV model. Then the comparative simulations of AL-AUV with the selected wings are completed, which simulate the AUV gliding through idealized windless air environment and gliding with Dryden wind influence. The result indicates that the method of wing design and simulation with the simulation platform based on SIMULINK is accurately effective and suitable to be widely employed.

关键词： Autonomous underwater vehicles Air launch Design Simulation Wings

Influence of Filling Ratio and Working Fluid Thermal Properties on Starting up and Heat Transferring Performance of Closed Loop Plate Oscillating Heat Pipe with Parallel Channels

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Journal of Thermal Science 2017年第1期26卷 73-81页

作者： SHI Weixiu pan Lisheng School of Environment and Energy Engineering Beijing University of Civil Engineering and Architecture Beijing Key Lab of Heating Gas SupplyVentilating and Air Conditioning Engineering State Key Laboratory of High-temperature Gas Dynamics Institute of MechanicsChinese Academy of Sciences

Using ethanol or acetone as the working fluid, the performance of starting up and heat transfer of closed-loop plate oscillating heat pipe with parallel channels(POHP-PC) were experimentally investigated by varying filling ratio, inclination, working fluids and heating power. The performance of the tested pulsating heat pipe was mainly evaluated by thermal resistance and wall temperature. Heating copper block and cold water bath were adopted in the experimental investigations. It was found that oscillating heat pipe with filling ratio of 50% started up earlier than that with 70% when heating input was 159.4 W, however, it has similar starting up performance with filling ratio of 50% as compared to 70% on the condition of heat input of 205.4 W. And heat pipe with filling ratio of 10% could not start up but directly transit to dry burning. A reasonable filling ratio range of 35%-70% was needed in order to achieve better performance, and there are different optimal filling ratios with different heating inputs- the more heating input, the higher optimal filling ratio, and vice versa. However, the dry burning appeared easily with low filling ratio, especially at very low filling ratio, such as 10%. And higher filling ratio, such as 70%, resulted in higher heat transfer( dry burning) limit. With filling ratio of 70% and inclination of 75°, oscillating heat pipe with acetone started up with heating input of just 24 W, but for ethanol, it needed to be achieved 68 W, Furthermore, the start time with acetone was similar as compared to that with ethanol. For steady operating state, the heating input with acetone was about 80 W, but it transited to dry burning state when heating input was greater than 160 W. However, for ethanol, the heating input was in vicinity of 160 W. Furthermore, thermal resistance with acetone was lower than that with ethanol at the same heating input of 120 W.

关键词： closed loop with parallel channels, plate pulsating heat pipe, filling ratio, working fluid thermalproperties, start up, heat transfer performance