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Search Results: 1 - 10 of 267861 matches for " br>魏玺 "
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The Characteristic Inversion of the Mid-course Missile Based on the Ellipse Model

Wei Xi-zhang,Ding Xiao-feng,Li Xiang,<br>,丁小峰,黎湘
电子与信息学报 , 2009,
Abstract: This paper is for the identification from the RCS sequence of the Mid-course missile.On the base of analyzing its motion and electromagnetic scattering characteristic,a new method using RCS magnitude changes with respect to the object gesture angle for inversing the mid-course object's long-short axis ratio and gesture angle to the line of the radar is presented.Comparing with the traditional ellipse method,the new method overcomes the disadvantage of the necessity for the maximal and minimal RCS value of t...

WEI Xi-Zhang,LI Xiang,ZHANG Zhao-Wen,FU Yao-Wen,<br>,黎湘
红外与毫米波学报 , 2000,
Abstract: It was studied how to calculate the temperature field of infrared target in general.First of all, the radiation of background was studied, then the theoretical models of several kinds of simple shape target were set up. By these models, the model of complex shape target was got to calculate the temperature field. Finally, the temperature of a target surface was calculated for two cases.
中国中药杂志 , 1994,
Abstract: 几种药用元胡的染色体数及其亲缘关系的探讨徐昭玺,魏建和(中国医学科学院药用植物资源开发研究所北京100094)植物的染色体数是遗传育种的基础及植物分类的重要依据,元胡在植物分类上是比较困难的一个属,因此研究染色体数对元胡的育种和分类都是很有意义的。一、材料和方法所用材料有浙江元胡CorydalisyanhusuoW.T.Wang;全叶元胡C.repensMandl.etMuhld.;齿瓣元朗C.remotaimFisch.exMaxim.;圆齿瓣元胡C.remotaFisch.exMax-im.f.r....
华西医学 , 2010,
华西医学 , 2011,
Numerical Simulation of Isothermal Chemical Vapor Infiltration Process for Fabrication of C/SiC Composites

WEI Xi,CHENG Lai-Fei,ZHANG Li-Tong,XU Yong-Dong,<br>,成来飞,张立同,徐永东
无机材料学报 , 2006,
Abstract: The multi-scale porosity model depicting infiltration induced changes of carbon fiber preform and the mathematical model depicting ICVI process for fabrication of C/SiC composites were developed. The integrated model was proposed to simulate densification behavior of C/SiC composites. The correspondences of calculation results and the experimental data indicate that the model is reasonable and feasible to characterize ICVI process of C/SiC composites. The calculated results, such as distribution of local porosity, uniformity of densification and evolution of global porosity during infiltration process, lay foundation of further research and optimization of ICVI process for fabrication of C/SiC composites.
Rough Classification of Air-Target with the Theory of Blind Number

Chen Hang-yong,Wei Xi-zhang,Li Xiang,Guo Gui-rong,<br>陈行勇,,黎湘,郭桂蓉
电子与信息学报 , 2006,
Abstract: This paper first summarizes the difficulty in detecting and identifying helicopter, then analysis the spectrum signature of radar echo signal from helicopter, and estimates the width of the spectrum modulated by helicopter blades. The author uses the width of the spectrum and applies the theory of blind number to a rough classification of helicopter and fixed-wing aircraft. The author provides the result of emulation, and the result proves the effectiveness of theoretic analyses and the algorithm of classification.
The Research on Doppler-only Imaging Algorithm of the Mid-course Missile Object

Ding Xiao-feng,Wei Xi-zhang,Hu Jie-min,Li Xiang,<br>丁小峰,,胡杰民,黎湘
电子与信息学报 , 2009,
Abstract: The midcourse missile imaging method is the key technology for the missile-defense system. Conventional ISAR imaging methods require a uniform function to compensate the phase of the echo. The function is difficult to acquire in the wideband case, so the ISAR imaging result is always smeared. This paper provides a new signal processing algorithm called time-frequency trunk line extraction method. By enhancing the amplitude of the time-frequency doppler which extracted from the narrowband radar return signal, the method improves the doppler imaging resolution effectively. The simulation results and anechoic chamber data of the representative cone-shaped object show that the imaging of the missile target can be obtained from the narrowband radar doppler information using this method.
西北农林科技大学学报(自然科学版) , 1994,
Abstract: 对泵站异步机组、单机补偿装置手动切换、取消拍门和底阀运行中可能出现的过电压、电流冲击及机组振动等问题进行分析,指出问题的严重性,并在机组保护接线中采取相应措施,保证泵站机组安全运行。
Numerical Simulation on Aerodynamic Heating and Thermal Stress of ZrB2-SiC Leading Edge

LIN Xiao-xuan,WU Hai-tang,WEI Xi,SHEN Zhi-xun,ZHANG Wei-gang,<br>蔺晓轩,武海棠,,沈志洵,张伟刚
过程工程学报 , 2010,
Abstract: Aerodynamic heating process and thermal stress of ZrB2-SiC leading edge as the component of scramjet engines were numerically investigated by finite-difference and finite-element methods, and the simulation results were verified through thermal structure tests with arc-heated wind tunnels. Simulation results showed that the temperature at stagnation point reached 1870 K in 5 s, and thermal stress of structure was up to 1240 MPa which was beyond the fracture strength of ZrB2-SiC material, when the inflow Mac...
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