提高天线丝杠传动速度的热应力分析

传动链末级采用丝杠传动的天线转速较低。为了最终提高天线转速,针对传统的结构计算的欠缺,提出了一种基于有限元热-结构耦合分析的设计方法。该方法利用动力学分析功能,结合传热学原理求解热流传递数值;通过引入数值结果的热-结构耦合分析,得到速度与应力的对应关系。通过动力学分析、热分析和静力分析的有机结合,对该类型结构计算进行了有益补充。结合工程案例示范,展示了该方法的应用前景。     

APPLICATION OF REDUCIBLE CUTSET AND REDUCIBLE LOOP TO ANALYSIS OF THE NETWORK

New concepts of reducible independent cutset and reducible independent loop are developedthrough an analysis of the ladder network.A new analytic method,named structural analysis method,is pres-entod.It evaluates the controllability and observability of a network based on its structure rather than onits state equation.Some problems in the conventional network analysis can be solved using this method.Re-sults obtained by this method are in good agreement with those obtained by that of state space analysis,butthis method is much simpler in use.A practical example is given.     

Microstrip transmission line analysis by the use of the least-squares collocation method

A simple method of analysis of microstrip transmission lines by the corner function method (eigenfunction approach) is presented. The inhomogeneous dielectric system of the microstrip is treated as a mixed boundary-value problem and is solved by the use of the least-squares collocation method. The results obtained by this method agree well with previous theoretical results and the method of analysis is much less laborious, simpler and faster.     

反演解析法提高CCD空间分辨率方法的修正及完善

修正及完善了用多次移位成像提高CCD空间分辨率的反演解析法。通过分析反演解析法的原理,修正了将空间分辨率提高2．5倍的解析关系式,同时阐述了把空间分辨率提高任意倍的移位原则。仿真实验证明了本方法的良好性能。     

铰支式桅杆底座绝缘子置换技术研究

本文基于 ANSYS 静力学分析方法，采用位移约束法、纤绳张力温度补偿法等，对铰支式桅杆底座绝缘子远距离置换进行了模拟分析计算，解决了静力分析中移动结构的刚度矩阵畸变、分析求解发散的问题，利用静力学分析模拟了桅杆底座绝缘子远距离置换的运动分析过程， 为工程实施提供了理论分析依据。     

基于核估计的成品率分析算法及其实现

本文改进了NBA(Non-parametric Boundary Analysis)算法，给出了一种基于核估计法的成品率分析算法。利用该算法不必事先假定参数服从何种分布，仅通过较少次数的仿真，便可获得成品率分析结果。而且可有效提高NBA算法的准确性，降低了算法复杂度。文中详细介绍该算法的实现方法。算例表明，该方法对电路设计进行快速成品率分析及电路的稳定性设计具有较好的应用前景。     

HSpice在电路内部参数容差统计分析中的应用

提出一种基于HSpice的器件内部参数蒙特卡罗统计分析方法对电子电路进行仿真设计。针对PSpice软件只能采用特定库元件进行统计分析的局限性,研究HSpice蒙特卡罗分析的技巧、程序语句参数的设置、输出结果的判读等,解决基于高精度内部参数器件模型的电路性能仿真,给出应用该方法实现电路内部参数蒙特卡罗统计分析的仿真过程。可以有效地提高电路设计的准确性、可靠性和电子产品生产的合格率。实验表明这种方法可以对组成电路器件的任意参数进行蒙特卡罗统计分析,包括MOS管、运放等的模型内部参数,在优化电路设计中具有很高的实用性。     

Classification of sit-to-stand locomotion task based on spectral analysis of waveforms generated by accelerometric transducer

A new method to evaluate the ability to rise from a chair by means of the analysis of the sit-to-stand locomotion task is introduced. In particular, the method is based on the frequency analysis of the acceleration measurements supplied by a home-made transducer.     

用于激光诱导离解光谱技术定量化分析的基体校正方法

激光诱导离解光谱技术作为一种物质元素分析手段,其主要目的是用来提供高精度的定量分析.通过分析传统定量化方法的不足之处,提出了基体校正法.此方法有效地减少了基体效应对测量结果带来的影响,放宽了对标准样本的要求,扩大了适用范围,并通过实验验证了此方法应用于激光诱导离解光谱技术定量化工作的可行性.     

表面响应法在埋置型大功率多芯片微波组件热布局中的应用研究

该文将有艰元模拟与基于统计试验的表面响应法(RSM)相结合,应用于特定需求的埋置型大功率多芯片微波组件热布局分析中,先通过ANSYS温度场分析,得出大功率芯片布局是影响整体温度和芯片结温的关键因素,再对一含有四个大功率芯片的微波组件模块进行了表面响应分析,得到了关于芯片坐标的线性回归方程,利用该方程可预测坐标组合下芯片...     

采用时频分析方法进行多目标信号的分辨

对雷达多目标回波信号进行了分析，针对采用传统时域、频域分析方法不能正确全面地反映信号细节信息特点，针对试验获取的含有多目标信息的真实数据，采用魏格纳-维尔分布、短时傅里叶变换、小波变换等时频分析的方法对这砦数据进行了多目标分辨的时频分析和仿真比较，找到适合工程实现的多同标分辨时频方法，并给出了实测信号的时频仿真结果。     

Numerical Solution of Dielectric Loaded Waveguides: II---Modal Approximation Technique

A numerical method is described for the solution of the electromagnetic fields in dielectric loaded waveguides. The method uses the cutoff modes of the waveguide, obtained by finite-element analysis, to determine by matrix methods the fields above cutoff. A theoretical comparison with the conventional finite-element method is given and a general, highly efficient computer program for the analysis of dielectric loaded waveguides by the new method is described. Dispersion curves and contour plots obtained from the program are shown for several geometrical configurations, and these results are compared with analytic values and those obtained by the conventional finite-element method.     

Analysis of arbitrarily shaped two-dimensional microwave circuitsby finite-difference time-domain method

A version of the finite-difference time-domain method adapted to the needs of S-matrix calculations of microwave two-dimensional circuits is presented. The analysis is conducted by simulating the wave propagation in the circuit terminated by matched loads and excited by a matched pulse source. Various aspects of the method's accuracy are investigated. Practical computer implementation of the method is discussed, and an example of its application to an arbitrarily shaped microstrip circuit is presented. It is shown that the method in the proposed form is an effective tool of circuit analysis in engineering applications. The method is compared to two other methods used for a similar purpose, namely the contour integral method and the transmission-line matrix method     

Application of spline wavelet transformation to the analysis of extended energy-loss fine structure

We propose a new analysis method of the extended energy-loss fine structure (EXELFS), applying the multi-resolution analysis (MRA) in the wavelet transformation. We select the cardinal spline wavelet where the rank-4 cardinal spline function is used as a scaling function to construct the mother wavelet. In contrast with the conventional analysis method, the present method is efficient in filtering out the high-frequency noise and low-frequency components introduced by the numerical analysis process without distorting the original signal components, which promises quantitative analyses with less uncertainties.     

Influence of thermal stress on temperature sensitivity of FBG-GFRP bars

The influence of thermal stress on the temperature sensitivity of fiber Bragg grating-glass fiber reinforce polymer(FBG-GFRP) bars is studied by three methods,namely,direct experimental calibration method,stress analysis(finite element analysis) method and the method of apparent temperature sensitivity coefficient.In comparison with the other two methods,fewer parameters are required and the calculation is simple in the method of apparent temperature sensitivity coefficient,while the analytical error is lim...     

电子战战法仿真博弈动态分析方法

用定量分析开发电子战战法动态分析方法是海军战役规划中必须解决的问题,借助仿真和博弈分析的混合方法,根据对博弈效用函数的计算,构建了基于识别真目标、假目标以及火力命中目标概率的二人非零和（TPNZS）非合作博弈模型来开发电子战战法动态分析方法,对两个典型的电子战战法性能的初步动态分析表明：战场势态的变化将导致最优电子进攻战法的混合策略从（0.000 0,0.502 9,0.497 1）变为（0.000 0,1.000 0,0.000 0）。     

Migration velocity analysis and prestack migration of common-transmitter GPR data

The accuracy of a migration image of ground-penetrating radar (GPR) depends strongly on the accuracy of permittivity distribution determined from multioffset data. This paper proposes a migration velocity analysis method using a genetic algorithm (GA). The objective function is defined as the summation of normalized zero-delay cross correlation of all common-image point gathers. Under the assumptions that the media are blockwise and that the permittivity of each block can be expressed as a polynomial with limited terms, all coefficients of the permittivity function of each block, which maximize the objective function, are determined by migration velocity analysis method with GA. Prestack migration is performed by a reverse-time migration method based on Maxwell's equations solved by the finite-difference time-domain method with a perfectly matched layer absorbing boundary conditions. The migration velocity analysis method is applied to synthetic common-transmitter datasets to test the method. Then, the velocity analysis and prestack migration method are applied to field data. From the distribution of dielectric constant obtained from the field data, water content is derived, and the depth of a water aquifer is deduced from the water content distribution and a migration stack profile.     

晶体管基本放大电路动态参数折算分析方法

本课程是电气自动化类专业的重要专业基础课之一,难理解、实践性强是本课程的重要特点。对放大电路的基本工作原理及性能指标的估算分析是课程核心内容,基本放大电路性能指标分析特别是动态参数分析尤为重要,动态参数分析除了常规的微变等效电路法之外,还可以通过参数折算的方法进行分析,使得电路分析更为简单,高效,对于模拟电子技术课程初学者来说有一定的学习参考作用。     

可约割集和可约回路及其在网络分析中的应用

本文以梯形网络为讨论对象,提出可约分的独立割集和可约分的独立回路的概念。从而导出结构分析法,解决了常规网络分析法中某些研究得尚不透彻的问题。结构分析的结果与状态空间分析法所得结果完全一致,而且使用简便。最后给出了实例。     

FDTD在宽带MIC魔T设计中的应用

首先简要介绍平面魔T的发展历史,指出了MIC和MMIC中魔T设计和分析存在的困难,具体分析了一种由槽线与微带线构成的魔T的物理原理,并给出了详细的等效电路图和计算公式.针对现在微波电路中魔T设计存在的困难,本文提出了将等效电路方法和时域有限差分算法相结合的设计分析方法,随后以这种魔T类型为例,设计了一个用在微波集成电路中的魔T,中心频率为6GHz、带宽为3-9GHz,详述了该方法的整个过程.在应用时域有限差分(FDTD)分析时,为了计算的准确性,采用了PML边界条件和非统一尺寸网格划分(non-uniform grid)方法.