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A Dynamic Reactive Power Control for DFIG Wind Turbines and Its Impacts on Distribution Protections

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电力系统自动化 2012年第8期36卷 185-190页

作者： Li, Haifeng Gao, xiang Wang, Gang Wu, Zhengrong pan, Guoqing College of Electric Power South China University of Technology Guangzhou 510640 China

With the increasing penetration of distributed generations(DGs)into power grids,the fault ride-through ability of DG is attracting more and more *** grid codes require a DG to maintain its connection with the grid during grid faults and to play an active role in the recovery of grid *** paper chooses the doublyfed induction generator(DFIG)as the typical wind turbine for ***,a dynamic reactive power control strategy is proposed to improve the fault ride-through characteristic of a *** contributions of a DFIG to the fault current under the dynamic reactive power control and the Crowbar control are analyzed and compared based on the mathematical expressions and control *** impacts of a DFIG under two control strategies on distribution protections are *** show that although a DFIG under the dynamic reactive power control provides more fault current component than one under the Crowbar control,its impacts on distribution protections are ***,a 10kV distribution network with a DFIG is simulated in PowerFactory *** simulation results prove the correctness of above theoretical analysis.

关键词：双馈风力发电机无功功率控制配电保护功率控制策略双馈感应发电机电网故障风力发电机组双馈电机

Critical hemodynamic therapy oriented resuscitation helping reduce lung water production and improve survival

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Chinese Medical Journal 2019年第10期132卷 1139-1146页

作者： pan pan Long-xiang Su xiang Zhou yun Long Da-Wei Liu Xiao-Ting Wang Department of Critical Care Medicine Peking Union Medical College Hospital Peking Union Medical College & Chinese Academy of Medical Sciences Beijing 100730 China.

Background: Increased extravascular lung water (EVLW) in shock is common in the critically ill patients. This study ai explore the effect of cardiac output (CO) on EVLW and its relevant influence on prognosis. Methods: The hemodynamic data of 428 patients with pulse-indicated continuous CO catheterization from Department of Critical Care Medicine, Peking Union Medical College Hospital were retrospectively collected and analyzed. The patients were assigned to acute respiratory distress syndrome group, cardiogenic shock group, septic shock group, and combined shock (cardiogenic and septic) group according to their symptoms. Information on 28-day mortality and renal function was also collected. Results: The CO and EVLW index (EVLWI) in the cardiogenic and combined shock groups were lower than those in the other groups (acute respiratory distress syndrome group vs. cardiogenic shock group vs. septic shock group vs. combined shock group: CO, 5.1 [4.0, 6.2] vs. 4.7 [4.0, 5.7] vs. 5.5 [4.3, 6.7] vs. 4.6 [3.5, 5.7] at 0 to 24 h, P=0.009;4.6 [3.8, 5.6] vs. 4.8 [4.1, 5.7] vs. 5.3 [4.4, 6.5] vs. 4.5 [3.8, 5.3] at 24 to 48 h, P=0.048;4.5 [4.1, 5.4] vs. 4.8 [3.8, 5.5] vs. 5.3 [4.0, 6.4] vs. 4.0 [3.2, 5.4] at 48 to 72 h, P=0.006;EVLWI, 11.4 [8.7,19.1] vs. 7.9 [6.6,10.0] vs. 8.8 [7.4,11.0] vs. 8.2 [6.7,11.3] at 0 to 24 h, P 0.05). In addition, there was no significant difference in tissue perfusion or renal function among the four groups during the observation peri

关键词： Extravascular lung water Cardiac output Tissue perfusion Organ function Prognosis

Influencing factors on elastic-plastic deformation of multi-layered surfaces under sliding contact

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中国有色金属学会会刊：英文版 2004年第z1期14卷 472-477页

作者： YAN Li pan Xin-xiang XU Jiu-jun CHENG Dong Institute of Materials and Technology Dalian Maritime University China Institute of Materials and Technology Dalian Maritime University China Institute of Materials and Technology Dalian Maritime University China Institute of Materials and Technology Dalian Maritime University China

Stress distribution in the gradient multi-layered surface under a sliding contact was investigated using finite element method(FEM). The main structure parameters of layered surface discussed are total layer thickness,layer number and elastic modulus ratio of layer to the substrate. A model of multi-layered surface contact with rough slider was studied. The effect of the surface structure parameters on the elastic-plastic deformation was analyzed.

关键词： gradient multi-layered surface elastic-plastic deformation surface structure parameter FEM

PSP-Finder:A Defect Detection Method Based on Mining Correlations from Function Call Paths

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Chinese Journal of Electronics 2018年第4期27卷 776-782页

作者： CUI Zhanqi CHEN xiang MU Yongmin pan Minxue WANG Rongcun Computer School Beijing Information Science and Technology University Sate Key Laboratory for Novel Software Technology Nanjing University School of Computer Science and Technology Nantong University School of Computer Science and Technology China University of Mining and Technology

Large scale programs usually imply many programming rules, which are missing from the specification documents. However, if programmers violate these rules in the process of programming, it is possible to introduce software defects. Previous works on mining function call correlation patterns only use structural information of the program, while control flow, data flow or other semantic information of the program are not exploited in those approaches. As a result, the defect detecting ability is restricted and high false rate is caused. This paper proposes a defect detection method based on mining function call association rules from program paths, which can be provided by simple static analysis. Then, the programs are automatically checked against the function call association rules for detecting suspicious defects. Based on this approach,experiments are carried out on a group of open source projects. The experiment results show that this approach can improve the capability of detecting defects and find more bugs related to program execution path. In addition,the false positive function call patterns and the overhead for manually validating suspicious defects are reduced.

关键词： Function call graphs Function call paths Mining association rules Defect detection

An intermodal transportation geospatial network modeling for containerized soybean shipping

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Journal of Ocean Engineering and Science 2017年第2期2卷 143-153页

作者： xiang Liu yun Bai Jihong Chen Department of Civil and Environmental Engineering RutgersThe State University of New JerseyUnited States Center for Advanced Infrastructure and Transportation(CAIT) RutgersThe State University of New JerseyUnited States College of Transport and Communications Shanghai Maritime UniversityChina

Containerized shipping is a growing market for agricultural exports,particularly *** order to understand the optimal strategies for improving the United States’economic competitiveness in this emerging market,this research develops an intermodal transportation network modeling framework,focusing on *** container *** upon detailed modal cost analyses,a Geospatial Intermodal Freight Transportation(GIFT)model has been developed to understand the optimal network design for *** *** on market demand and domestic supply figures,the model is able to determine which domestically produced soybeans should go to which foreign markets,and by which transport *** research and its continual studies,will provide insights into future policies and practices that can improve the transportation efficiency of soybean logistics.

关键词： International shipping Rail Truck Barge Agricultural logistics Intermodal

The Chen-Ruan Cohomology of Almost Contact Orbifolds

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Acta Mathematica Sinica,English Series 2010年第1期26卷 77-88页

作者： Fan DING yun Feng JIANG Jian Zhong pan School of Mathematics Peking University Beijing 100871 P. R. China Department of Mathematics University of Utah 155S 1400E JWB233 Salt Lake City UT 84112 USA Institute of Mathematics Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 P. R. China

Comparing to the Ch-~Ruan cohomology theory for the almost complex orbifolds, we study the orbifold cohomology theory for almost contact orbifolds. We define the Chen-Ruan cohomology group of any almost contact orbifold. Using the methods for almost complex orbifolds, we define the obstruction bundle for any 3-multisector of the almost contact orbifolds and the Chen^Ruan cup product for the Che-Ruan cohomology. We also prove that under this cup product the direct sum of all dimensional orbifold cohomology groups constitutes a cohomological ring. Finally we calculate two examples.

关键词： almost contact orbifolds Chen Ruan cohomology twisted sectors almost complex orbifold

Non-destructive study of fruits using grating-based X-ray imaging

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Nuclear Science and Techniques 2017年第2期28卷 57-60页

作者： Sheng-xiang Wang Ren-Fang Hu Kun Gao Faiz Wali Gui-Bin Zan Da-Jiang Wang Zhi-yun pan Shi-Qiang Wei National Synchrotron Radiation Laboratory University of Science and Technology of China Hefei 230029 China

Grating-based X-ray imaging can make use of conventional tube sources to provide absorption, refraction and scattering contrast images from a single set of projection images efficiently. In this paper, a fresh cherry tomato and a dried umeboshi are imaged by using X-ray Talbot–Lau interferometer. The seed distribution in the scattering image of the cherry tomato, and the wrinkles of epicarp in the refraction image of the umeboshi, are shown distinctly. The refraction and scattering images provide more information on subtle features than the absorption image. Also, the contrast-to-noise ratio values show distinguishing capacity of the three kinds of imaging techniques. The results confirm that grating-based X-ray imaging is of great potential in non-destructive fruit testing.

关键词： Non-destructive testing X-ray imaging Talbot–Lau interferometer Fruit testing

Synthesis of Sulfur/Selenium-containing Polyester with Recyclability and Controllable Hydrophilicity and Glass Transition Temperature

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Chinese Journal of Polymer Science 2023年第12期41卷 1836-1845,I0004,I0005页

作者： Wen-Jing Li xiang-Qiang pan Jian Zhu Zheng-Biao Zhang Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application Department of Polymer Science and EngineeringCollege of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China

We present a ring-opening polymerization of bridged cyclic lactone utilizing alcohol as the initiator and organic base as the *** γ-butyrolactone monomers(PhSGBL and PhSeGBL)were synthesized efficiently from commercially available 3-cyclohexene-1-carboxylic *** to the ring strain of the bridged structure,ring-opening polymerization of this type of γ-butyrolactone derivative was successfully carried out under mild conditions,e.g.,using ethylene glycol as the initiator and a commercial catalyst[1,5,7-triazabicyclo[4.4.0 dec-5-ene(TBD)]]as the catalyst at 30℃.The obtained polymer could be degraded to its monomer for recycling in the presence of ZnCl_(2) as a *** and PhSeGBL could also be copolymerized with ε-caprolactone to tune the glass transition ***,the hydrophilicity of the obtained sulfur-containing polymers could be adjusted by selectively oxidizing the thioether side group to sulfone/sulfoxide,which offered a way to tune the hydrophilicity of *** the other hand,the obtained selenium-containing compound could be degraded in the presence of m-CPBA(3-chloroperbenzoic acid),which offered potential application in sustained drug release.

关键词： Ring-opening polymerization Polyester Closed-loop recycling Selective oxidation

An Encrypted Image Retrieval Method Based on SimHash in Cloud Computing

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Computers, Materials & Continua 2020年第4期63卷 389-399页

作者： Jiaohua Qin Yusi Cao Xuyu xiang yun Tan Lingyun xiang Jianjun Zhang College of Computer Science and Information Technology Central South University of Forestry&TechnologyChangsha410004China School of Computer and Communication Engineering Changsha University of Science and TechnologyChangsha410114China College of Engineering and Design Hunan Normal UniversityChangsha410012China

With the massive growth of images data and the rise of cloud computing that can provide cheap storage space and convenient access,more and more users store data in cloud ***,how to quickly query the expected data with privacy-preserving is still a challenging in the encryption image data *** this goal,this paper proposes a ciphertext image retrieval method based on SimHash in cloud ***,we extract local feature of images,and then cluster the features by *** on it,the visual word codebook is introduced to represent feature information of images,which hashes the codebook to the corresponding ***,the image feature vector is generated by SimHash searchable encryption feature algorithm for similarity *** experiments on two public datasets validate the effectiveness of our ***,the proposed method outperforms one popular searchable encryption,and the results are competitive to the state-of-the-art.

关键词： Cloud computing SimHash encryption image retrieval K-means