双曲拱坝的累计自重应力

通过用三维有限元方法按计划施工顺序计算了某高双曲拱坝在自重、灌浆及水压荷载下的累计应力．并研究了不同施工阶段的累计自重应力的特点及改善、利用该应力的工程措施．     

坚硬地基异弹模重力坝应力分布规律及其简捷算法的修正

本文用５Ｈ宽深地基八节点平面等参元方法计算了中等高度的各种不同坝体弹模比和不同下游坡率的坚硬地基重力坝，分析了异弹模重力坝坝体的应力分布规律并提出了符合异弹模重力坝特性的修正简捷材力计算法．     

各种合成纤维帘子线的性能特点

本文对合成纤维帘子线包括尼龙6、、尼龙66、聚酯和Kevlar等4种材料、按照轮胎帘子线使用的要求,从强伸、回弹性、热收缩和动态力学性能进行了较系统的测试。进而对以上4种合成纤维帘子线的特性以及对不同轮胎类型的适应性作了分析和比较。     

白光相衬实验

在相衬实验中,设相板中心波长使相板有π/2的相移,通过理论分析,得到:(1)单色光波长偏离相板中心波长越远,相衬像对比度越低;(2)准单色光相衬像对比度与谱带宽度及准单色光波长与相板中心波长偏移量有关;(3)在一定条件下,白光相衬像的光强分布与相应的单色光相衬像的光强分布一致.若选择合适的实验条件,可使像对比度取最大值.实验结果与理论一致.     

离心压气机叶轮与扩压器的流动分析

本文用数值计算方法分析了离心式压气机叶轮与扩压器内部的复杂全三维粘性流场。利用高速大内存计算机，较细致地揭示了离心压气机式叶轮与扩压器的内部流动，并做了相应的对比实验，测试结果定性地证实了数值计算的结论。     

Two virus-encoded RNA silencing suppressors, P14 of Beet necrotic yellow vein virus and S6 of Rice black streak dwarf virus

Functional analysis for gene silencing suppressor of P14 gene of Beet necrotic yellow vein virus and S6 gene of Rice black streak dwarf virus was carried out by agro- infiltration with recombinant vectors of Potato virus X. The phenotype observation of green fluorescent protein (GFP)expression and Northern blot showed that the gene silencing of gfp transgenic Nicotiana benthamiana induced by homologous sequence was strongly suppressed by the immixture infiltration of either the P14 or the $6. In the suppressed plants, the gfp mRNA accumulation was higher than that in the non-suppressed controls and the symptoms caused by PVX infection became more severe, especially the gfp DNA methylation of plant genome was significantly inhabited when co-infiltrated with RBSDV S6 gene. These results suggested that these two virus genes were potentially to encode for proteins as RNA silencing suppressors.     

大开口对船舶板架稳定性和极限承载力的影响

选取典型船舶板架，采用ANSYS系统，对开口和不开口的板，分别进行了特征值屈曲分析和极限承压屈曲分析，同时，运用便于简化处理的相当梁系法，将加筋板架，近似看作由带附连翼板的交叉梁系构成，转换以后，给出了一套工程近似计算方法，经分析比较，得知：板的屈曲模式所对应的屈曲压力并不一定是最低的，高应力区出现了梁（桁）腹板平面外的失稳，大开口边缘构件的倾向刚度大大削弱，纵桁的理论论界应力降低。     

Temporal-spatial characteristics of vegetation cover and desertification of China by using remote sensing data

Based on the NOAA advanced very high resolution radiometer (NOAA-AVHRR) remote sensing data of 1982 — 1999. the normalized difference vegetation index (NDVI) reflecting the surface vegetation cover has been obtained. Using the empirical orthogonal function analysis, the temporal-spatial eigenvectors of NDVI are given, and the characteristics of the spatial distribution of vegetation cover and its temporal variation together with the desertification of China are analyzed. It is found that the surface vegetation cover has seriously deteriorated in most part of China since 1995. along with the intensified desertification. All these are mainly caused by human activities although the climate change is responsible for the damage of surface vegetation cover to some extent.     

Preliminary study on land surface characteristics over Huaihe River Basin

The analysis of the flux observation dada from the Huaihe River Basin Experiment (HUBEX) shows that, in semi-humid monsoon regions, latent heat flux is as important as sensible heat flux in most situations. Moreover, it can even dominate the sensible heat flux in cropland and paddy field. This is distinct from that for arid and semi-arid regions where the sensible heat flux is dominant. Under clear sky conditions, the soil temperatures in different vertical layers all exhibit certain diurnal variations, and the magnitude decreases with depth to less than 1°C at a depth of 60 cm. This depth is considered as the transition layer for the soil moisture variation. On the other hand, the vertical profile of soil water content varies with the soil texture and even weather conditions, and the layer with maximum soil water content can also be found in Jiangji station during June 1998.     

应用人工神经网络的无功／电压控制新方法

本文利用人工神经网络中的HOPFIELD连续模型(HNN)来求解电力系统中的无功优化问题,对HNN模型作了改进,使其能够处理等式约束和不等式约束,从而使得HNN模型可以应用于求解非线性规划问题。在算法上,和传统的无功优化方法不同,本方法不区分状态变量和控制变量,只以节点电压作为DNN模型能量函数中的自变量。该方法开发了HNN神经网权值矩阵的稀疏性。通过对雅可比矩阵的修正,引入了变压器变比的变化。另外,本文还从理论上分析了HNN模型的能量的性质,探讨了一种修正HNN模型能量函数中参数的方法,从而保证了解的可行性。最后,通过两机系统,IEEE-6节点,IEEE-30节点系统的测试,验证了这两种模型的正确性。