1999年长江洪水及几点认识

Following the basin wide heavy flood on Changjiang River in 1998, a si gnificant flood occurred in 1999. Comparative analysis of both floods in terms of flows and flooding situations shows that both floods had one common feature, that is, the flood stages were fairly high. But they differed greatly at the sa me time, that is, the 1998 flood was a basin wide heavy one while the 1999 flood was a significant local one. At Yichang station there occurred eight flood pea ks in 1998, while in 1999 only three peaks took place. The maximum peak dischar ge at this station in 1999 was 57 600 cubic meters per second, which was smaller than that in 1998. The maximum flood-volume in 30 d of the 1998 flood at this s t ation equaled that in 1954, when an extraordinary heavy flood happened on the River, while the maximum flood-volume in 30 d in 1999 was 25.8 billion cubic me t ers per second smaller than the 1998 one. It is seen that inflow floods from th e upstream Changjiang River (above Yichang) in 1999 were not so big. Comparison of flood volumes in longer period shows that the 1999 flood was relatively conc entrated while the 1998 one had lasted longer duration. Analysis shows that flo oding situations in both years differed significantly in terms of the flood volu mes diverted from river channels due to dyke breaches and collapses, the cases o f polder embankment collapses, the areas of inundated cultivated land and the nu mbers of dangerous events for hydraulic structures. These differences had been resulted from the different properties of both floods and the dyke strengthening efforts made after the 1998 flood. It is seen that flood control engineering c onstructions initiated in the days following the 1998 flood have played an impor tant role in fighting the 1999 flood.     

铝电解槽磁流体稳定性有限元分析

本文采用有限元法求解分层磁流体小扰动方程系统特征值，研究铝电解槽稳定性。研究结果表明，在没有电磁力时，铝液表面波动（内波）是稳定的。存在电磁力时，它会激发铝液表面波动的某些低频长波分量不稳定性，高频短波不受影响。被激发的不稳定波动频率和扰动增长率与电流密度，磁感应强度垂直分量，铝电解槽长宽比，电解质和铝液的密度差，厚度等因素密切相关。减少电流密度，磁感应强度，增加电极距离和铝液厚度可以提高铝电解槽的稳定性。这对铝电解槽优化设计和在线控制有重要意义。     

被动式氚取样器性能的实验研究

介绍了核设施工作场所和环境空气中氚化水蒸气HTO的监测，被动式氚取样器在国外已经得到非常广泛的应用，所研制的被动式氚取样器，特别适用于7－30d的长期取样，给出该取样周期内空气中HTO浓度的平均值。     

壳体理论在水压爆破中的应用

在壳体理论的基础上,考虑到薄壳型结构水压爆破的特点,提出了一种新的药量计算公式,并得到了初步实际工程验证.     

一种新型微带光子带隙结构的优化设计

本文对一种渐变尺寸的新型光子带隙结构进行了优化设计。根据优化后得出的最优结构参数 ,设计出PBG结构。实验结果证明 ,这种优化后的新型结构可以在保持阻带抑制幅度的同时减小通带内的波纹     

HTR-10燃料元件装卸系统冷态调试

10MW高温气冷实验堆（HTR－10）是一座球床堆，由燃料元件装卸系统实现燃料元件的装卸和循环，且不需要停堆，为保证HTR－10的正常运行，燃料元件装卸系统必须安全，可靠，为此，必须对燃料元件装卸系统进行周密，细致的调试试验和验证，本文介绍了燃料元件装卸系统冷调试的主要调试项目，调试方法和调试结果。     

新型纺织纤维及其染整特性

文章概述了新型纤维纺织品的特点，介绍了目前市场上流行的几种新型纤维（大豆蛋白纤维、竹纤维、PBT和PTT）的基本性能及其染整特性，并指出了它们各自存在的问题。     

詈语的语用认知价值探讨

詈语在自然语言中广泛存在和使用是不争的事实，但长期以来詈语被视为教材编写和课堂教学的禁区。文章在探讨詈语定义和分类的基础上，对詈语在交际中的认知语用价值进行了实例论证。进而提出在语言教学中对詈语重新定位的问题。