Vibration Analysis and System Simulation for a Stalled Wind Turbine     

HE Jing  HE Yu-lin  JIN Xin  LIU Hua 《保鲜与加工》2007,(5):91-95

The aerodynamic characteristic of wind turbine is calculated by applying the Blade Element Momentum(BEM) theory.Also finite element mode analysis is done for the tower and the rotor.Then the multi-dynamic model of the wind turbine is built in Adams.Also the drive chain is calculated by applying state space method and programmed in Matlab/ Simulink.With that the combined simulation of vibration characteristics is carried out on the base of MATLAB/Simulink and ADAMS,in which the transmission effects and aero-elasticity coupling is fully considered.The results show that the method is able to simulate the vibration characteristic almost the same as software Bladed,which is well-known for analyzing performance and loads for the design and certification of wind turbines.  相似文献   

Pinning Theory of Fermi Energy and Surface State Measurement of ZnSnO3 Gas Sensitive Material     

LI Ji  LIU Tian-mo  ZHAO Xian-rui  WANG Zhong-chang  LI Jia-ming 《保鲜与加工》2006,(5):55-58

In order to research the state of energy bands and gain and loss of electrons on the surface of ZnSnO_(3),it is put forward that Pinning theory of Fermi energy is applied to development of gas sensitive materials.The relative position between surface state and conduction band on surface of zinc tin complex oxide(ZnSnO_(3)) gas sensitive material has been investigated by utilizing oxidation redox couple,FeCl_(2)/ FeCl_(3),which have high surface state.Fermi energy is pinned at about 0.2 eV below conduction band E_(cs)on the surface of ZnSnO_(3).It has been determined that additives doping ratio,addition concentration and working atmosphere have no effect on this value.Therefore,pinning theory of Fermi energy has been verified by using this method.  相似文献   

The Problem of Real Option and Its Frontier Commentary     

ZHOU Zhuo-hua 《保鲜与加工》2005,(11):142-145

The method of real option has already become an important tool in the fields of enterprises value evaluation, company finance, strategy investment management, investment decision, finance analysis, corporation merger and acquisition and so on. But there is a lot of problems in both theory and practical application for the method of real option. This article will analyze the research frontier problem of real option and indicate the further research direction.  相似文献   

OPTIMIZATION OF BIPARTITE JOINS WITH GRAPH THGORY     

Zeag Yongning Tong Fu 《保鲜与加工》1989,(2):43-49

An optimization approach for multi-relational joins based on the matching concept in graph theory is introduced. The basic idea lies in constructing a join graph from an expression of N-relation query, and seeking for a maximun matching with minimun total weight. The algorithm for bipartition(X, Y) is proposed in this paper.  相似文献   

PROBLEMS OF THE BEST APPROXIMATION IN WIENER-SOBOLEV SPACE     

Zhang Jianhua 《保鲜与加工》1992,(4)

  相似文献   

The Maximum Edge-Edge Connectivity of Quasi-Regular Graphs     

Yang Xiaofan  He Zhongshi Chen Tinghuai  Chen Siqing 《保鲜与加工》1995,(6):62-67

The edge-edge connectivity of a graph is defined,and a class of quasi-regulargraphs is proposed with a maximum edge-edge connectivity.  相似文献   

Customer Service Satisfaction Evaluation System and Method Viewed From Supply Chain Management     

LIU Jing-nan  MENG Wei-dong  WU Jun 《保鲜与加工》2004,(1):146-151

Based on experience in customer service evaluation,through the analysis of many factors affecting customer satisfaction calculation estimate, customer service evaluation rules as well as customer-oriented and supply chain partner-oriented methods are developed and discussed from the view of supply chain, besides, we construct two sets of customer satisfaction evaluation systems, in which we perform non-dimensional analysis on evaluation system to form single factor evaluation matrix after using improved AHP to determine each factor item's weighting ,utilizing fuzzy decision theory to construct evaluation model for integrated estimate. This evaluation method is scientific, round and objective with more stability and convienience in practical use.  相似文献   

Parsimonious Covering Probability Model for Turbogenerator Vibration Faulty Diagnosis     

ZHANG Bi de  SUN Cai xin  OU Jian  HU Xue song 《保鲜与加工》2002,(5):101-103107

The turbogenerator vibration faults have the character of variety. Many faults often occur synchronously. This paper introduces a diagnosing model based on parsimonious covering theory and probability. A model for turtogenerator's fault diagnosis is proposed. The availability of this method is proved by two fault diagnosis examples of turbogenerator. The results show that the model proposed can be used for multi_fault diagnosis together. It may make up shortage for some of expert systems and neural networks in some aspect. From the practice,this model has higher reliability and practicability.  相似文献   

Synthetic Assessment of Power Transformer Condition Based on Matter-element Theory     

XlONG Hao  SUN Cai-xin  DU Peng  DAI Yao  WANG Qian 《保鲜与加工》2006,(10):24-28

Condition assessment on power transformer is an important approach to improve reliability of transformer and provide proper decision-making for condition-based maintenance. For long, static assessment method used in the past has already not adapted to the development of modem electricity transmission and distribution technology. So based on the deficiency of fuzzy synthetic assessment method, matter-element synthetic assessment method is introduced. The method can evaluate transformer condition not only in quality but also in quantity. Because each index weight can be given fairly and fast through improved analytic hierarchy process, which need not carry on consistency chec accuracy of assessment can be improved. Examples analysis has proved that assessment method of power transformer condition based on matter-element theory is rational and effective.  相似文献   

Incentive Mechanism for Team Cooperation Based on Implicit Side Contract     

WEI Guang-xing  PU Yong-jian  QIN Yan-hong 《保鲜与加工》2006,(12):136-140

Aiming at the free-riding problem in team incentive, this paper designs a dynamic incentive mechanism based on implicit side contract with dynamic game theory by introducing the reasonable assumption that there is horizontal monitor in team production. The theoretic analysis indicates that the dynamic incentive mechanism, in which a strict group incentive compatibility contract is taken at the first stage and an individual incentive compatibility contract is taken at the second stage, can implement team cooperation uniquely in the general condition of risk aversion and stochastic production by only two stage repeated game.  相似文献