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The Journal of China Universities of Posts and Telecommunications 2009年第1期16卷 9-15,43页

作者： YU Zhi-jun WEI Jian-ming liu hai-tao Wireless Sensor Network Research and Development Center Shanghai Institute of Microsystem and Information Technology Shanghai 200050 China

Target tracking is one of the most important applications of wireless sensor networks. Optimized computation and energy dissipation are critical requirements to save the limited resource of sensor nodes. A new robust and energy-efficient collaborative target tracking framework is proposed in this article. After a target is detected, only one active cluster is responsible for the tracking task at each time step. The tracking algorithm is distributed by passing the sensing and computation operations from one cluster to another. An event-driven cluster reforming scheme is also proposed for balancing energy consumption among nodes. Observations from three cluster members are chosen and a new class of particle filter termed cost-reference particle filter （CRPF） is introduced to estimate the target motion at the cluster head. This CRPF method is quite robust for wireless sensor network tracking applications because it drops the strong assumptions of knowing the probability distributions of the system process and observation noises. In simulation experiments, the performance of the proposed collaborative target tracking algorithm is evaluated by the metrics of tracking precision and network energy consumption.

关键词： target tracking cost-reference particle filtering energy-efficient wireless sensor networks (WSNs)

Investigation of Combining Plant Genotypic Values and Molecular Marker Information for Constructing Core Subsets

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Journal of Integrative Plant Biology 2006年第11期48卷 1371-1378页

作者： Jian-Cheng Wang Jin Hu Ning-Ning liu hai-ming Xu Sheng Zhang Department of Agronomy Zhejiang University Hangzhou 310029 China

In the present study, a strategy was proposed for constructing plant core subsets by clusters based on the combination of continuous data for genotypic values and discrete data for molecular marker InformaUon. A mixed linear model approach was used to predict genotyplc values for eliminating the environment effect. The ＂mixed genetic distance＂ was designed to solve the difficult problem of combining continuous and discrete data to construct a core subset by cluster. Four commonly used genetic distances for continuous data （Euclidean distance, standardized Euclidean distance, city block distance, and Mahalanobls distance） were used to assess the validity of the conUnuous data part of the mixed genetic distance; three commonly used genetic distances for discrete data （cosine distance, correlaUon distance, and Jaccard distance） were used to assess the validity of the discrete data part of the mixed genetic distance, A rice germplasm group with eight quantitative traits and information for 60 molecular markers was used to evaluate the validity of the new strategy. The results suggest that the validity of both parts of the mixed geneUc distance are equal to or higher than the common geneUc distance. The core subset constructed on the basis of a combination of data for genotyplc values and molecular marker information was more representative than that constructed on the basis of data from genotypic values or molecular marker informaUon alone. Moreover, the strategy of using combined data was able to treat dominant marker informaUon and could combine any other continuous data and discrete data together to perform cluster to construct a plant core subset.

关键词： cluster core subset genotypic value mixed linear model molecular marker information

Turbulence Modulations in the Boundary Layer of a Horizontal Particle-Laden Channel Flow

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Chinese Physics Letters 2010年第6期27卷 129-132页

作者： LI Jing liu Zhao-Hui WANG Han-Feng CHEN Sheng liu Ya-ming HAN hai-Feng ZHENG Chu-Guang State Key Laboratory of Coal Combustion Huazhong University of Science and Technology Wuhan 430074

Turbulence modulations are experimentally investigated using particle image velocimetry （PIV） in the lower boundary layer of a fully developed horizontal channel flow. A simultaneous two-phase PIV measurement technique is adopted to acquire the turbulent statistics quantities and to examine the coherent structures in the near-wall region. Polythene beads with diameters of 60 μm are used as dispersed phases, and the PIV measurements have been performed at three mass loadings varying from 2.5 ×10^-4 to 5 × 10^-3. All the experiments are performed at a wall shear Reynolds number of Reτ = 430. The results show that the presence of the particles suppresses the coherent structures, with shorter streamwise extent of the quasistrearnwise structures, and then, the wall-normal velocity fluctuations and shear Reynolds stresses are both decreased in the near-core region. In addition, as a result of the particle wake, the turbulence intensity and shear Reynolds stress both increase in the vicinity of the wall. Due to the drag effects of the particles on the gas, the streamwise velocity gradients decrease in the outer region and increase in the viscous sublayer, meanwhile the thickness of the viscous sublayer also decreases. These results cause the peak values of the streamwise velocity fluctuations adjacent to the wall to increase, and the peak positions shift to the wall. This is the reason for decreasing the near-wall region and increasing the near-core region of the streamwise velocity fluctuations in appearance.

关键词： Reynolds stress Wakes Flow in channels Turbulence intensities Statistical analysis Drag

Microwave Absorption in Electron Cyclotron Resonance Plasma

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Chinese Physics Letters 2000年第1期17卷 31-33页

作者： liu ming-hai HU Xi-Wei WU Qin-Chong YU Guo-Yang Institute of Plasma Physics Chinese Academy of SciencesHefei 230031 Department of Modern Physics University of Science and Technology of ChinaHefei 230026

The microwave power absorption in electron cyclotron resonance plasma reactor was investigated with a two-dimensional *** results indicated that there are two typical power deposition profiles over the entire parameter region:(1)microwave power deposition peaks on the axis and decreases in radial direction,(2)microwave power deposition has its maximum at some radial position,i.e.,a hollow *** spatial distribution of electron temperature resembles always to the microwave power absorption *** dependence of plasma parameter on the gas pressure is discussed also.

关键词： microwave absorption Electron

Early Stage of Pulsed Discharge in Water

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Chinese Physics Letters 2001年第11期18卷 1493-1495页

作者： LU Xin-Pei PAN Yuan liu Ke-Fu liu ming-hai ZHANG Han-Hong Department of Electric Engineering Huazhong University of Science and TechnologyWuhan 430074 Department of Mechanic Engineering University of Science and Technology of ChinaHefei 230026

The bubble radius at the early stage of discharge in water is investigated using high-speed photography. Some simulation results on the bubble radius are presented, which are in agreement with the experimental results, with a maximum difference of about 10%. The reasons why the peak pressure of the first shock wave is only related to the energy released in the bubble during the first half period are addressed. The energy released in the bubble after the first half period increases the bubble pulsation period, but it produces no more than 10% under the peak pressure of the second shock wave.

关键词： wave. bubble radius

Fractal model of spontaneous imbibition in low-permeability reservoirs coupled with heterogeneity of pore seepage channels and threshold pressure

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Petroleum Science 2024年第2期21卷 1002-1017页

作者： ming-Sheng Zuo Hao Chen Xi-Liang liu hai-Peng liu Yi Wu Xin-Yu Qi National Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing102249China College of Safety and Ocean Engineering China University of Petroleum(Beijing)Beijing102249China

Spontaneous imbibition(SI)is an important mechanism for enhancing oil recovery in low-permeability *** to the strong heterogeneity,and the non-Darcy flow,the construction of SI model for lowpermeability reservoirs is extremely ***,traditional SI models based on single or averaged capillary tortuosity ignore the influence of heterogeneity of pore seepage channels and the threshold pressure(TP)on ***,in this work,based on capillary model and fractal theory,a mathematical model of characterizing SI considering heterogeneity of pore seepage channels is *** this basis,the threshold pressure was introduced to determine the pore radius at which the wetted phase can displace *** proposed new SI model was verified by imbibition experimental *** study shows that for weakly heterogeneous cores with permeability of 0-1 m D,the traditional SI model can characterize the imbibition process relatively accurately,and the new imbibition model can increase the coefficient of determination by 1.05 ***,traditional model has serious deviations in predicting the imbibition recovery for cores with permeability of 10-50 m *** new SI model coupling with heterogeneity of pore seepage channels and threshold pressure effectively solves this problem,and the determination coefficient is increased from 0.344 to 0.922,which is increased by2.68 *** low-permeability reservoirs,the production of the oil in transitional pores(0.01-0.1μm)and mesopores(0.1-1μm)significantly affects the imbibition recovery,as the research shows that when the heterogeneity of pore seepage channels is ignored,the oil recovery in transitional pores and mesopores decreases by 7.54%and 4.26%,*** analysis shows that increasing interfacial tension,decreasing contact angle,oil-water viscosity ratio and threshold pressure will increase imbibition *** addition,there are critical values for the influence of these factors o

关键词： Spontaneous imbibition Low-permeability reservoir Fractal model Threshold pressure Capillary tube

Numerical Simulation on the Production Mechanism of Surface-Wave Plasmas Sustained along a Metal Rod

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Chinese Physics Letters 2014年第3期31卷 103-106页

作者： ZHU Long-Ji CHEN Zhao-Quan YIN Zhi-Xiang WANG Guo-Dong XIA Guang-Qing HU Ye-Lin ZHENG Xiao-Liang ZHOU Meng-Ran CHEN ming liu ming-hai College of Electrical and Information Engineering Anhui University of Science and Technology Huainan 232001 State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan 430074 State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian 116024

For interpreting the production mechanism of surface-wave plasmas sustained along a metal rod, electromagnetic simulation on the electromagnetic field distributions and particle-in-cell/Monte Carlo collision （PIC/MCC） simulation of the ionization process are present. The results show that the enhanced electric field of surface plasmon polaritons （SPPs） can be excited in the ion sheath layer between the negative-voltage metal rod and the surface-wave plasmas, which is responsible for maintaining the plasma discharge. Moreover, the spatio-temporal evolutions of plasma density and electric fields are simulated by the PIC/MCC model. It is further suggested that the expanded ion sheath layer can extend the length of plasma domain by increasing the plasma absorbed energy from SPPs.

关键词： SURFACE waves (Fluids) RESEARCH PLASMA (Ionized gases) -- Research ELECTROMAGNETISM ELECTROMAGNETIC theory PHYSICS research

Risk Assessment of Deep-Water Horizontal X-Tree Installation

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China Ocean Engineering 2024年第2期38卷 210-220页

作者： MENG Wen-bo FU Guang-ming HUANG Yi liu Shu-jie HUANG Liang GAOYong-hai CNOOC China Limited Zhanjiang BranchZhanjiang 524057China Key Laboratory of Unconventional Oil and Gas Development Ministry of Education(China University of Petroleum(East China))Qingdao 266580China

Due to the high potential risk and many influencing factors of subsea horizontal X-tree installation,to guarantee the successful completion of sea trials of domestic subsea horizontal X-trees,this paper established a modular risk evaluation model based on a fuzzy fault ***,through the analysis of the main process oftree down and combining the Offshore&Onshore Reliability Data(OREDA)failure statistics and the operation procedure and the data provided by the job,the fault tree model of risk analysis of the tree down installation was ***,by introducing the natural language of expert comprehensive evaluation and combining fuzzy principles,quantitative analysis was carried out,and the fuzzy number was used to calculate the failure probability of a basic event and the occurrence probability of a top ***,through a sensitivity analysis of basic events,the basic events of top events significantly affected were determined,and risk control and prevention measures for the corresponding high-risk factors were proposed for subsea horizontal X-tree down installation.

关键词： subsea horizontal X-tree risk assessment fuzzy fault tree modular risk evaluation model

Electromagnetic Wave Attenuation in Atmospheric Pressure Plasmas

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Chinese Physics Letters 2001年第9期18卷 1225-1226页

作者： liu ming-hai HU Xi-Wei JIANG Zhong-He LU Xin-Pei GU Cheng-Lin PAN Yuan College of Electric and Electronic Engineering Huazhong University of Science and TechnologyWuhian 430074

The properties of electromagnetic waves in atmospheric pressure plasmas are investigated with the Lorentz model. The effects of the electromagnetic wave frequency, plasma density, and the electron-neutral collision frequency on the attenuation of electromagnetic waves are discussed. The numerical results indicate that the wave attenuation is stronger at the region of the longer wavelength and at the higher plasma density.

关键词： density. wave neutral

Preliminary Analysis of Hysteresis Phenomenon in Electron Cyclotron Resonance Plasma

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Chinese Physics Letters 2001年第4期18卷 559-561页

作者： liu ming-hai HU Xi-Wei YU Guo-Yang WU Qin-Chong PAN Yuan Department of Electrical Power Engineering Huazhong University of Science and TechnologyWuhan 430074 Institute of Plasma Physics Chinese Academy of SciencesHefei 230031

The hysteresis phenomenon in electron cyclotron resonance plasma has been investigated theoretically by solving the equations of the density and energy balance of electron and by taking the effects of several collisions such as ionization and recombination into *** results show that multiple-steady states in experimental measurements can be characterized by considering a fact that the energy balance function has three different real roots in certain region of *** root represents a saddle point and other roots represent stable points,that is,the system is *** effects of ionization and the energy transformation due to the collisions between the electron and neutral gas are discussed also.

关键词： roots Electron energy