VARIABLE DAMP STRUCTURAL RELIABILITY DUE TO MULTIPLE RANDOM EXCITATIONS AND SENSETIVITY ANALYSIS     

Zhang Xiangwei Xu Meihe 《保鲜与加工》1991,(4):8-15

The reliability of random vibration is discussed,and then by using the first order perturbation method and with the aid of relation of the systemic response function to the first order sensetivity of variable damp parameter, the rate of change of structural reliability indication is derived, therefore the constraint equation to guarantee reliability for the structural optimization design is proved and the satisfactory result is obtained,test and the practicability of this method is tested.  相似文献   

RECREATING SMALL SEAMLESS TUBE MILLS BY PIERCING INSFEAD OF ROLLING     

Zhang Caian Mo Lilong Lu Zhiwen 《保鲜与加工》1992,(6):128-131

This paper discuss the effects of automatic plug mills in small seamless tube mills. Far from traditional ideas,the auther comes rp with mew ideas, which adot the mew process of replacing rolling by piercing,a huge sum of economical interests and great social benefits will be gained.  相似文献   

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   

Correlation and Arithmetic of Operational Risk Measurement Basing on Loss Distribution Approach     

ZHANG Hong-yi  LU Jing 《保鲜与加工》2007,(5):131-134

Based on the principles of operational risk measurement provided by Basel II,the paper discusses the problem of operational risk correlations among different business lines / risk types.The correlation coefficients between the aggregate losses among different business lines / risk types are calculated.Copula arithmetic is put forward to compute correlation coefficients matrix of aggregate losses.Besides,the result is used to calculate the capital requirement of operational risk.  相似文献   

白血病抑制因子（LIF）及其受体在月经 周期猕猴卵巢内的表达     

岳占碰  李世杰  张学明  韩春田  郭斌  王洪斌  杨增明 《中国农学通报》2006,22(2):14-14

应用免疫细胞化学方法对白血病抑制因子（leukemia inhibitory factor, LIF）、白血病抑制因子受体（leukemia inhibitory factor receptor, LIFR）和gp130在月经周期猕猴卵巢内的表达进行了研究。结果表明：LIF、LIFR和gp130在猕猴卵巢内的表达量随月经周期的不同而变化，LIF及其受体在增殖期卵巢内的表达量高于分泌期的卵巢。LIF及其受体在原始卵泡、腔前卵泡和有腔卵泡的卵细胞内表达量均较高，在颗粒细胞、卵泡膜、卵巢生殖上皮和卵巢基质中有少量表达，而在闭锁卵泡、退化的黄体和卵巢髓质中未见表达。LIF及其受体在猕猴卵巢内的表达可能受卵巢分泌的类固醇激素所调控，LIF可能通过自分泌或旁分泌的方式在猕猴卵泡发育及排卵等过程中起重要作用。  相似文献   

Minimal Periodic Solutions of SuperquadraticFirst Order Convex Hamiltonian Systems     

Zhang Shiqing 《保鲜与加工》1996,(6):96-103

This paper generalizes all known results on Rabinowitz's minimal periodic solution conjecture under the assumption that Hamiltonian function is C2 strictly convex.  相似文献   

STATE VARIABLE METHOD FOR DYNAMIC SIMULATION OF HVDC SYSTEMS     

Zhang Wei Ren Zhen Qin Yihong Liao Qing 《保鲜与加工》1990,(1):56-62

A flexible mathematical model used for dynamic simulation studies of HVDC systems which is based on the stale variable method is presented, and the correspongding computer program has been implemented. Generality, easy to use, and suitable to run on microcomputers are the main features of the model and the computer program. Therefore the model is easy to be extended for application. An example is given in the paper to verily the coneclness of the model and the program.  相似文献   

THREE CRITICAL POINTS THEOREM AND ITS APPLICATIONS     

Zhang Shiqing 《保鲜与加工》1989,(1):105-107

In this paper, by use of the pseudo-gradient vector field, the three critical points theorem in [2] is extended to the C1 function in the Ba-nach space, and therefore the three critical, points theorem in [5] is strengthened and the existence of the saddle point of the C2 function is discussed.  相似文献   

Time-frequency Analysis of Heart Sound     

ZHOU Jing  YANG Yong-ming 《保鲜与加工》2004,(4):159-162

The structural defects of the heart are often reflected in the sounds that heart produces. Because of the non-stationary of the PCG signal, it is important to maintain its time-frequency character. We discuss the Short-Time Fourier Transform (STFT) method and the wavelet method. Some normal and abnormal heart sounds were analyzed by these methods. We can see the advantage and disadvantage of them obviously from the examples.  相似文献   

Study on The origin of The Cracks And Their Elinination In Expanded Pearlite And Waste Glass Compound Decorative puank     

Zhang Zhiqiang  Lu Jian  Wu Fang  Zou Yicong 《保鲜与加工》1995,(3):60-64

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