A new algorithm to optimize Barker code sidelobe suppressionfilters

The authors suggest a new algorithm for binary coding waveform sidelobe reduction after matched filtering and present a general method by which optimized sidelobe suppression filters for Barker codes can be obtained with a peak output sidelobe 2.62 dB lower than the results found in the literature (for 13-b Barker code). This optimization algorithm is also promising for other binary coding waveforms, such as truncated pseudonoise (PN) sequences and concatenated codes. This new approach can readily be applied to sidelobe-reduction filter design for other binary coding waveforms, such as truncated PN sequences, concatenated codes, etc., which often find their applications in radar systems and spread spectrum communication systems     

受冲压作用固体发动机喷管堵盖应力分析

基于Ｖｏｎ Ｋａｒｍａｎ模型，对受冲击压力作用的喷管堵盖计算模型进行受力分析，计算考虑到了几何非线性和材料非线性的影响，得到了冲压作用下的喷管堵盖变形和应力分析结果。并对不同升压速率情况进行了对比分析，指出了升压速率对喷管堵盖结构受力影响的重要性。     

姿控发动机稳态故障效应分析

在考虑了实际试车过程中已出现过或可能出现的故障的基础上，建立了恒庆挤压式双组元姿态控制发动机系统的稳志故障模型，并利用梯度法对该模型进行了求解。在此基础上进行了几种典型故障的仿真，分析了它们所产生的效应，识别出这些故障的模式。最后给出了用于分离和监测故障的关键参数。     

引射器引气与压气机抽气建立加力燃烧室喷口低压条件的综合分析

从建设投资、运行费用、设计、操作、维护等诸多方面对引射器引气与压气机抽气建立加力燃烧室高空模拟试验器喷口低压条件进行全面分析和对比,得出引射器引气方案优于压气机抽气方案。     

一种基于遗传算法的动力学系统辨识方法

把遗传算法与最大似然法相结合，形成了一种基于遗传算法的动力学系统辨识方法，并以某轴对称战术导弹的非线性气动力参数仿真辨识为例，利用仿真技术，检验了该方法的实用性和有效性。结果表明，该方法是十分有效的。     

单片机电动机经济运行测试仪的研究

本文介绍了利用８０３１单片机实现三相异步电动机经济运行参数测试的基本原理，说明了硬件、软件结构和主要数学模型。讨论了对钳式电流互感器进行非线性频率补偿问题、并分析了实现自动量程转换及由Ｅ２ＰＲＯＭ构成定标系统的方法。最后给出研制结果。     

用N-S方程求解柔壁翼型绕流

用 N- S方程数值模拟带有自适应柔壁被动控制的翼型粘性绕流。用时间推进法求解这种准定常绕流。在时间历程中 ,柔壁自适应变化 ,最后与整个流场一起趋于定常。比较了柔壁和刚壁两种翼型的压力场和等马赫线及等密度线等     

HPM脉冲形成网络的理论分析与计算

通过理论分析和计算，设计一个高电压脉冲形成网络，用来得到高功率微波源需要的长脉冲电压方波。     

Dynamic change of ERPs related to selective attention to signals from left and right visual field during head-down tilt

To study further the effect of head-down tilt (HDT) on slow positive potential in the event-related potentials (ERPs), the temporal and spatial features of visual ERPs changes during 2 hour HDT (-10 degrees) were compared with that during HUT (+20 degrees) in 15 normal subjects. The stimuli were consisted of two color LED flashes appeared randomly in left or right visual field (LVF or RVF) with same probability. The subjects were asked to make switch response to target signals (T) differentially: switching to left for T in LVF and to right for T in RVF, ignoring non-target signals(N). Five sets of tests were made during HUT and HDT. ERPs were obtained from 9 locations on scalp. The mean value of the ERPs in the period from 0.32-0.55 s was taken as the amplitude of slow positive potential(P400). The main results were as follows. 1) The mean amplitude of P400 decreased during HDT which was more significant at the 2nd, 3rd and 5th set of tests; 2) spatially, the reduction of mean P400 amplitude during HDT was more significant for signals from RVF and was more significant at posterior and central brain regions than that on frontal locations. As that the positive potential probably reflects the active inhibition activity in the brain during attention process, these data provide further evidence showing that the higher brain function was affected by the simulated weightlessness and that this effect was not only transient but also with interesting spatial characteristics.     

新生代的气候效应与碳循环

对发生于新生代的６次巨大天体撞击作用（６５Ｍａ，３４Ｍａ，１５Ｍａ，２４Ｍａ，１．１Ｍａ，０．７Ｍａ）的气候效应进行的模拟表明，这６次巨大天体撞击作用产生的尘埃进入平流层后，可使全球平均温度下降至零度以下，降温效应持续时间最长可达３０年之久，首次在模拟中考虑全球性森林大火产生的ＣＯ２和死亡生物分解生成的ＣＯ２的温室效应，研究表明这两种作用使大气中ＣＯ２增量最大仅达６７％，其增温效应远远低于尘埃层产