X波段双极化有源相控阵天线的设计

机载或星载X波段有源相控阵雷达系统具有很高的分辨率，由于雷达系统使用了大量双极化子阵组成的有源相控阵天线（俯仰面和方位面均需扫描），频率的升高使得子阵馈线网络的可用面积受到了很大的限制。本文着重论述了有源相控阵天线中的双极化阵设计，提出了一系列解决方法，进而叙述了整个天线阵的设计。     

等距码的对偶距离分布及其性质

本文主要讨论了等距码的对偶距离分布及其性质，然后利用这些性质将［１］中的某些结果推广到ｑ元等距码情形，并得到了其对偶距离分布的递推关系式，最后，本文给出了ｑ元等距码的码字数目的一个上界。     

环件轧制中晶粒变化的计算机模拟

金属微观结构变化影响产品机械性能。本文将金属再结晶数学模型与三维热刚塑性有限元结合起来进行模拟计算，获得了环件轧制中晶粒变化的三维分布规律，及与以往不同的轧制力和力矩变化。所用方法有普遍适用性。     

A new approach to the mechanism of chlorine evolution: Separate examination of the kinetic steps using ac impedance on a rotating thin ring electrode

In the absence of a bulk diffusion effect, it is shown for the first time that the impedance spectra for the chlorine evolution reaction on a rotating thin ring electrode comprise three consecutive semicircles in the capacitive half of the complex plane. The first (highest frequency) semicircle is due to the charge-transfer resistance for chloride discharge and the simultaneous chlorine adsorption coupled to the double-layer capacitance. The second semicircle (around 5 Hz) is due to the adsorption and desorption of a chlorine intermediate. The third (lowest frequency, around 0.5 Hz) semicircle is due to the relaxation of surface oxygen species. The impedance data allow the steps of the overall reaction to be examined individually. On a Pt surface the rate of chloride discharge and simultaneous chlorine adsorption (the admittance of the first semicircle) is first order with respect to chloride concentration and has a potential-dependence close to 58 mV/decade. The rate of the adsorption and desorption process (the admittance of the second semicircle) is second order with respect to chloride concentration, and has a potential dependence close to 30 mV/decade. The time constant for the adsorption/desorption processes is ca 20 ms, independent of electrode potential in the range studied. These features are consistent with a mechanism in which a faster discharge reaction (Cl⁻ Cl_ad + e) is followed by a slower surface combination reaction (2Cl_ad → Cl₂), but inconsistent with mechanisms in which ion + atom desorption is predominant, the initial chloride discharge is slow, or a unipositively charged chlorine species is involved.     

高分辨率双侧向测井响应数值模拟分析

 我国自行研制的新型的高分辨率双侧向测井仪已逐渐投入大规模的生产应用，可为解决油田薄层油气藏的勘探开发问题提供有力的支持。本文利用有限元方法对新型的高分辨率双侧向测井仪及国内目前大规模应用的常规双侧向测井仪的分层能力、探测深度、侵入影响和井眼影响等响应特征进行了数值模拟，并对其测井响应进行了对比分析。数值模拟表明：与常规双侧向测井相比，虽然高分辨率双侧向测井资料井眼的影响更复杂，但测量结果既能得到较高纵向分辨率，又具有较深的径向探测深度，基本上可以取代常规双侧向测井仪在测井中应用。文中数值模拟结果可以为测井作业人员和解释人员在资料验收及解释处理等方面提供参考和指导。     

Construction of a control system for disturbance rejection using a dual observer

A well‐known control system which can reduce the adverse effects of disturbances is a disturbance observer. However, in many cases of mechanical systems, system disturbances which do not satisfy the matching condition may be imposed. Therefore, it may be difficult to reduce the adverse effects of the disturbances by the traditional disturbance observer. In this paper, a method of control system synthesis for disturbance rejection using a dual observer is proposed. This method is based on the zeroing induced by the disturbance localization problem. This problem may be solved by dividing the state space into observable subspace and unobservable subspace. As compared with an H_∞ controller based on perfect observation, the usefulness of the proposed control system for disturbance rejection is demonstrated by numerical simulations for a two‐mass spring system. © 2002 Scripta Technica, Electr Eng Jpn, 138(4): 50–60, 2002; DOI 10.1002/eej.1138     

莫莫格湿地生态演变及水源解决途径探析

湿地的生态演变是区域性生态演变的前奏，而水是生态环境的控制性因素。     

依靠弯道控导河势流路

在天然河道中，河势演变虽具有一定的随机性，但仍有一定的规律可循，在一个河段内，一般可归纳出2－3条基本流路，为控制河势变化，需要选择出一条基本流路进行河道整治，当连续发生枯水期或洪水期时，部分河段的河势可能出现大的变化，为防止不利河势向下游传播，可修建较长的龙头弯道工程，利用龙头弯道工程分段调整，控导河势，保持河势稳定。     

双波长Nd：YAG脉冲激光器的实验研究

根据多波长同时振荡条件，我们建立了大能量１０６４ｎｍ和１３１８ｎｍ同时运转的双波长脉冲Ｎｄ：ＹＡＧ激光器。得到了１０６４ｎｍ和１３１８ｎｍ的激光输出能量分别为０．５９４Ｊ和０．８６１Ｊ，效率分别为０．３１％和０．４５％。实验结果说明了该双波长激光器有较好的时间和空间重选性。     

基于神经网络的河道浅滩演变预测模型

河道浅滩演变是一个复杂的非线性动力学过程, 作者借助神经网络处理非线性问题的优势, 在分析影响河道浅滩演变因素的基础上, 建立了预测河道浅淮演变的BP网络模型, 并对模型中的输入因子和样本的提取进行了探讨. 以闽江竹岐至侯官河段为实例,用“试控法”给出了BP网络模型的建模方案, 用正交设计原理选取相应的训练样本集, 利用该样本集对网络进行学习和训练, 并用训练好的BP网络模型预测浅滩上年内最小水深和年平均淤积厚度. 计算结果表明: 模型预测结果与实际值吻合良好. 这为河道浅滩演变预测研究提供了新方法.