谈中小水电项目建设程序管理——以贵州中小水能资源开发利用现状为例

分析近年来贵州省中小水电资源开发建设活动中存在的因项目建设程序管理不规范所造成的水能资源开发无序、资源浪费以及工程事故隐患等诸多问题,依据水利工程建设管理有关法律法规,从项目建设管理角度进一步探讨了中小型水电项目建设管理的基本程序。图2幅。     

Effect of stress triaxiality levels in crack tip regions on the characteristics of void growth and fracture criteria

The behaviour of void growth in the crack tip regions of four specimen geometries with different stress triaxiality levels have been investigated by the FEM method and experimental observations in plane strain and plane stress cases respectively. It was found that the shape change of growing voids, the configurations of a blunting crack tip and the sizes of decreasing ligament between the void and the crack tip are strongly dependent upon the stress triaxiality levels. Under the condition of plane stress, the stress triaxiality on the ligaments of cracks are nearly the same for different specimen geometries, also the void growth, crack tip blunting asnd decreasing of ligament size are identical for various specimens with increasing load levels, which lead to the conclusion that the J_i-value is independent of specimen geometries. However, in the plain strain case, different void growth, crack tip blunting and decreasing in ligament size for various stress triaxiality levels directly caused the J_i-value to be dependent on the specimen geometries. It was found that when the void is linked to the blunting crack tip by the extrapolation to the zero ligament from FEM calculations, the J_i values, measured experimentally, are underestimated slightly.     

石家庄市室内氡及其子体浓度

本文报道了用双滤膜法对石家庄市室内空气中氡及其子体浓度的调查结果。47个房间室内氡年平均浓度为17.0Bq·m~(-3),氡子体平均浓度是7.14Bq·m~(-3)。氡及其子体浓度的日变化是清晨4—8时出现峰值。季节变化是夏秋季低,冬季高,全年的最低值出现在8月,最高值出现在11月。     

油田放射性作业人员外周血淋巴细胞染色体畸变的观察

本文调查了油田212例受γ射线和中子混合辐射照射的作业人员和30例正常人的外周血淋巴细胞染色体畸变。作业人员受γ射线照射的人均年受照剂量为1.28mGy。调查结果表明,放射性测井人员与正常人相比染色体畸变率有显著差异。     

聚氧化乙烯—聚磷酸钠共混物的钠离子导电性

研究了聚氧化乙烯-聚磷酸钠共混物的钠离子导电性和低分子量多缩乙二醇对共混物导电性的改进作用。结果表明,降低多缩乙二醇的分子量以及增加其含量都有利于提高共混物的离子导电率。增塑剂改进共混物导电性的实质是提高共混物的非晶相含量,共混物内钠离子传导发生在非晶区,聚合物链段运动是离子传导的主要推动力。     

Self-consistent calculation of the lasing eigenmode of thedielectrically apertured Fabry-Perot microcavity with idealized ordistributed Bragg reflectors

Optical confinement in the dielectrically apertured Fabry-Perot microcavity is investigated theoretically. The apertured region is first treated as embedded in an idealized planar waveguide to show that the confined eigenmode's resonant frequency can cut off parasitic waveguide modes existing outside the aperture, and lead to three-dimensional optical confinement. For more realistic cavities with nonunity mirror reflectivities, self-consistent calculations of the eigenmode characteristics are performed for the limit of an optically thin aperture to derive the lowest order confined eigenmode frequency, threshold susceptibility, and mode profile. The analysis is then extended to treat dielectric cavities based on Bragg reflectors     

无染色牛肝过氧化氢酶薄晶的图象处理

本文根据Ｐ．Ｎ．Ｔ．Ｕｎｗｉｎ和Ｒ．Ｈｅｎｄｅｒｓｏｎ等人提出的对生物大分子晶体的囹象处理方法，对无染色的牛肝过氧化氢酶薄晶的显微象和衍射图进行了图象处理，最后得到了牛肝过氧化氢酶薄晶的二维结构。从中可以看出，牛肝过氧化氢酶薄晶的一个单胞由４个子胞组成，４个子胞排列方向各异。     

平面扇形可倾瓦气体推力轴承的优化设计

气体动压轴承在小型透平机械中有着诱人的应用前景．本文介绍了平面扇形可倾瓦气体推力轴承的工作特性计算及其参数优化的方法．利用自编的软件取得了瓦块最佳直径比和支承位置等参数的优化结果，并且在微机上实现了该种轴承的优化设计．     

SAW滤波器简化衍射频响的计算方法

提出了由一个变迹ＩＤＴ叉指换能器和一个均匀ＩＤＴ组成的ＳＡＷ滤波器简化衍射频响的计算方法，即将均匀ＩＤＴ简化成单根指计算其衍射频响。该方法与未简化衍射频响的计算方法相比，计算量大为减小，前者约为后者的（Ｎ为均匀ＩＤＴ的指对数）。并给出了一个实例，用未简化与简化方法分别计算了其衍射频响，结果表明，两者符合得较好。