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Research on dual-stator winding multi-phase high-speed induction generator with rectifier load

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Science China(Technological Sciences) 2008年第6期51卷 683-692页

作者： WANG XiangHeng1 & WU XinZhen2 1 department of electrical engineering, Tsinghua{3., Beijing 100084, China 2 department of electrical engineering, Qingdao{3., Qingdao 266071, China department of electrical engineering Tsinghua University Beijing China department of electrical engineering Qingdao University Qingdao China

Based on analysis and calculation of the relation between current harmonics and MMF harmonics in the dual-stator winding multi-phase high-speed induction gen-erator with a rectifier load, a new idea, which divides the generator system into two sub-systems to be analyzed individually, is presented. For the sub-system of the 12-phase power winding with a rectifier load, the loop current method is used to establish network equation set in terms of the network graph theory. The numerical stability problem is solved by alternating use of fixed time-step and varied time-step, and the voltage and current with their fundamental components of the power winding are obtained. For the other sub-system of the induction generator with dual-stator winding and solid cage rotor, the electromagnetic field analysis method and the multi-variable optimization approach are combined to get the con-trol winding current and stator frequency. Calculated results well match experiment results, indicating that the new proposed method is of effectiveness and high ac-curacy.

关键词： dual-stator winding induction generator rectifier load MMF analysis loop current method finite element method optimization approach

Resistless photochemical etching of a silicon wafer by UV laser with an H_2O_2 and HF aqueous solution

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Chinese Science Bulletin 2002年第2期47卷 164-167页

作者： YANG Jie, LIU Yanfa & M. Murahara State Key Laboratory of Ultrafast Spectroscopy of Zhongshan university, Guangzhou 510275, China department of electrical engineering of tokai university, Japan State Key Lab. Ultrafast Spectrosc. Zhongshan University Guangzhou 510275 China

A new resistless etching method has been de-veloped for Silicon wafers. This new method uses an aqueous solution consisting of hydrogen peroxide (H2O2) and hydro-gen fluoride (HF) as the activating etchants. A 193.nm ArF excimer laser and a 266 nm fourth harmonic generation Nd:YAG laser were used as the photon sources. Results showed that pattern etching has been achieved without any photoresist film. In the case of the 193.nm laser, the optimal etching appeared at a 1.3.H2O2/HF ratio, where an etchdepth of 210 nm was achieved with a fluence of 29 mJ/cm2 and shot number of 10000. At the same conditions, the etch depth with H2O2 and HF solution was three times of that by using H2O and HF mixture. In the case of the 266 nm Nd : YAG laser, the optimal etching appeared at twice ratio of H2O2/HF, where the etch depth of 420 nm was achieved witha fluence of 12 mJ/cm2 and shot number of 3.000. Results showed that the etch effect of the 266 nm Nd : YAG laser was more desirable than that of the 193.nm ArF

关键词： UV laser resistless photochemical etching hydrogen peroxide (H2O2).

Mathematic Expression of Kinetic Compensation Effect and Relationship between the Exothermic Decomposition Temperature and Critical Temperature of Thermal Explosion of Eighty-six Energetic Materials

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含能材料 2001年第1期9卷 8-9页

作者： HU Rong zu 1, YANG De suo 2, ZHANG Jiao qiang 3. (1. department of Chemistry,Northwest university, Xi′an 710065, China 2. department of Chemistry and Chemical{3., Baoji College of Arts and Science, Baoji 721007, China 3. department of 西北大学陕西西安 710065 宝鸡文理学院陕西 721007 西北工业大学陕西西安 710072

Two relationships are established using the least squares method,between the kinetic parameters (the apparent activation energy and pre exponential constant),and the exothermic decomposition temperature and ther... 详细信息

关键词： critical temperature of thermal explosion decomposition temperature DSC energetic materials.

Analysis on cohesive crack opening displacement considering the strain softening effect

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Science China(Physics,Mechanics & Astronomy) 2006年第1期49卷 88-101页

作者： WANG Limin1, XU Shilang2 & ZHAO Xiqiang3.1. Mechanics department, Shandong university of Technology, Zibo 255049, China 2. Civil engineering department, Dalian university of Technology, Dalian 116024, China 3. Mathematics department, Ocean university of China, Qingdao 266071, China Mechanics department Shandong University of Technology Zibo China Civil engineering department Dalian University of Technology Dalian China Mathematics department Ocean University of China Qingdao China

In order to investigate the crack propagation in quasi-brittle materials like rock, ceramic and concrete, Hillerborg and his co-researchers abstracted the fracture process zone in front of a stress free crack in terms of a “fictitious crack zone”. On the fictitious crack zone, cohesive stresses distribute following a given softening relationship of stress vs. crack opening. Based on the polynomial or power series expression of cohesive crack opening displacement, the relationship of the cohesive stress vs. the crack opening displacement is established using elastic theory and integral equation, and some unknown physics variables are obtained using variation approach. The calculation results gained in this paper are close to the experimentally test ones.

关键词： cohesive crack, softening, dissipation work, variation approach.

Wideband Beamforming for Multipath Signals Based on Frequency Invariant Transformation

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International Journal of Automation and computing 2012年第4期9卷 420-428页

作者： Wei Liu Communications Research Group,department of Electronic & electrical engineering,{3. of Sheffield,Sheffield,S1 3.D,UK Communications Research Group Department of Electronic & Electrical Engineering University of Sheffield Sheffield UK

It is well known that the performance of conventional adaptive beamformers degrades severely due to the presence of coherent or correlated interferences(multipath propagation) and various techniques have been developed to improve the performance of the ***,most of the work in the past has been focused on the narrowband *** this paper,the wideband beamforming problem in the presence of multipath signals is addressed,with a novel approach proposed by employing a pre-processing stage based on the frequency invariant beamforming(FIB) *** this approach,the received wideband array signals are first processed by an FIB network,and then a traditional narrowband adaptive beamformer or an appropriate instantaneous blind source separation(BSS) algorithm can be applied to the network *** is shown that with the proposed structure,cancellation of the desired signal is reduced,leading to a significantly improved output signal to interference plus noise ratio(SINR).

关键词： Wideband beamforming multipath signals frequency invariant beamforming blind beamforming convolutive mixtures.

Spatial continuity incorporated multi-attribute fuzzy clustering algorithm for blood vessels segmentation

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Science China(Information Sciences) 2010年第4期53卷 752-759页

作者： HAO JuTao1*, ZHAO JingJing2 & LI MingLu3.1School of Optical-electrical and Computer engineering, university of Shanghai for Science and Technology, Shanghai 200093. China 2{3. of electrical engineering, Shanghai university of Electric Power, Shanghai 200090, China 3.3. of Computer Science and engineering, Shanghai Jiaotong university, Shanghai 200240, China School of Optical-electrical and Computer engineering University of Shanghai for Science and Technology Shanghai China department of electrical engineering Shanghai University of Electric Power Shanghai China department of Computer Science and engineering Shanghai Jiaotong University Shanghai China

A three-dimensional representation of vasculature can be extremely important in image-guided neurosurgery, pre-surgical planning. In this paper, a spatial continuity incorporated multi-attribute fuzzy clustering algorithm (MAFCM S) is proposed to segment entire blood vessels from TOF MRA images. This clustering method takes both the intensity information and the geometrical information into account, while most of the cur- rent clustering methods only deal with the former. In this method, a new dissimilarity measure, which integrates the intensity and the geometry shape dissimilarity, is introduced. Because of the presence of the geometrical information, the new measure is able to differentiate the pixels with similar intensity values within different geometrical shape structures. Experimental results show that the new algorithm can get better segmentation.

关键词： fuzzy c-means clustering scale space analysis spatial continuity blood vessel segmentation multi-attribute fuzzy clustering

Morphology and electrical conductivity of PACS

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Journal of Environmental Sciences 2000年第3期12卷 319-324页

作者： GAO Bao\|yu\+1, LIU Zong\|gang\+2, YUE Qin\|yan\+3. ZHAO Hua\|zhang\+3.(1. department of Environmental engineering, Shandong university, Jinan 250100, China 2. Environmental Monitoring Station of Huaiyin, Jinan 250022, China 3. department of Environ 山东大学山东济南 2 50 1 0 0 山东济南市槐荫区环境监测山东济南 2 50 0 2 2

Polyaluminium chlorides with sulfate ion(PACS) were prepared by using AlCl 3.6H 2O, Al(SO 4) 3.18H 2O and Na 2CO 3.as raw materials. The effects of basicity ( r ), Al 3. /SO 4 2- molar ratio and aging time on the morphology of PACS were observed by transmission electrical microscope. The influence of aging time on charge neutralization and coagulation effect of PACS was studied. The effects of basicity ( r ), Al 3. /SO 4 2- molar ratio and aging time on the electrical conductivity of PACS solution were also investigated. The experimental results show that the degree of polymerization of polyaluminium chloride(PAC) increases when SO 4 2- ion is added. The higher the basicity( r ) and the longer the aging time, the larger the size of polymer PACS. The ability of PACS neutralizing the charge on Kaolinite decreases with the increase of aging time. The electrical conductivity of PACS solution(the concentration of Al 3. ion is 0.18 mol/L) with different aging time is the function of the basicity and Al 3. /SO 4 2- molar ratios and has its maximum at r =0.5 and Al 3. /SO 4 2- =12.

关键词： coagulant PACS morphology transmission electron microscope electrical conductivity coagulation

Rank of loop, constraint degree of path, coupling degree of graph and their application

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Progress in Natural Science:Materials International 2005年第2期15卷 79-85页

作者： YANG Tingli1*, LUO Yufeng2, ZHANG Ce3.and YAO Fanghua1(1. SINOPIC Jinling Petrochemical Corp., Nanjing 21003., China 2. department of Mechanical engineering, Nanchang university, Nanchang 3.0029, China 3. department of Mechanical engineering, Tianjin university, Tianjin 3.0072, China) Jinling Petrochemical Corp. SINOPIC Nanjing 210037 China Dept. of Mechanical Eng. Nanchang Univ. Nanchang 330029 China Dept. of Mechanical Eng. Tianjin Univ. Tianjin 300072 China

Some new concepts (rank of a loop, degree of freedom of a graph, path unit and ordered path arrangement, constraint degree of path, coupling degree of a graph, basic graph, etc.), formulas, and algorithms, are proposed in this paper. Based on these concepts, a new systematic theory and practical method for the design of topological structure, kinematics and dynamics of mechanical systems is established. Some conjectures and problems needed to be researched are also put forward. The concepts, formulae and algorithms presented in this paper will find wide potential applications.

关键词： rank of loop degree of freedom of graph constraint degree of path coupling degree of graph

Comparison study of trapped water in human erythrocytes by EPC and DSC method and its application

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Science China(Technological Sciences) 2004年第3期47卷 343-351页

作者： ZHAO Gang1, HE Liqun1, GUO Xiaojie2, LIU Zhong3. LUO Dawei1,3.& GAO Dayong1,3.1. Cryobiomedical engineering Research Institute, department of Thermal Science and Energy engineering,{3. of Science and Technology of China, Hefei 23.027, China 2. Red Cross Blood Center of Hefei, Hefei 23.022, China 3. department of Mechanical engineering,{3. of Kentucky, Lexington, KY 40506-0108, USA Cryobiomedical engineering Research Institute Department of Thermal Science and Energy Engineering University of Science and Technology of China Hefei 230027 China Red Cross Blood Center of Hefel Hefei 230022 China department of Mechanical engineering University of Kentucky Lexington KY 40506-0108 United States

The novel differential scanning calorimetry method for determining trapped water volume of human red blood cell during freezing process has been reexamined. Results show that the final erythrocyte volume is 53. of its isotonic volume after freezing to -40℃. An electronic particle counter (MultisizerTM III, Beckman Coulter Inc., USA) was used to measure cell volume changes in response to hypertonic solution. Using this approach, when extracellular solution was 3.86 mOsm, the equilibrium cell volume was found to be 57% of its isotonic value. Both results indicate that 3.%—40% of intracellular water is trapped and cannot respond to osmotic difference between intra- and extracellular solution. These findings are consistent with the published data: at least 20%—3.% of the isotonic cell water volume is retained within RBCs during freezing. Some applications of the values of trapped water are addressed.

关键词： differential scanning calorimeter/DSC, electronic particle counter/EPC, cell volumetric change, red blood cell/RBC/erythrocyte