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91.
摘要:针对企业网上年检系统在互联网环境下的可信与安全问题,提出了基于PEa/CA系统的应用安全解决方案,即通过在系统的身份认证和业务处理过程中数字信封、对称密钥加密和数字签名技术的综合应用以及相关功能和流程的设计,确保业务通信的机密性、完整性、身份确认和不可抵赖性,为面向社一会公众的、基于互联网的电子政务应用提供一种成熟、可靠的安全机制。 相似文献
92.
Buildings, their surroundings and related enterprises produce more CO2, generate more pollution, consume more energy, and waste more natural resources than any other human enterprise or industry. Moreover, considerable parts of these environmental impacts are the results of the lodging industry [1]. 相似文献
93.
Beneficiation of low-grade diasporic bauxite with hydrocyclone 总被引:1,自引:0,他引:1
Low-grade diasporic bauxite was treated with hydrocyclone of small cone-angle. The effects of apex diameter, feed pressure and feed concentration on separation indexes were tested, and then the separation process was discussed by hydrokinetics tentatively. The results show that the increase of apex diameter changes the spacial locality of the envelope of zero vertical velocity, resulting in decrease of the ratio of Al2O3/SiO2 in overflow and increase of the recovery of Al2O3 in underflow, while feed pressure and feed concentration have no remarkable effect on the spacial locality of the envelope of zero vertical velocity, however, the separation indexes are improved by the increase of feed pressure, but are worsened by the increase of feed concentration. 相似文献
94.
定义了平面杆系中的失效评估杆元、以及该杆元的正则杆端弯矩和正则杆端曲率,据此引入了杆件失效包络图、工作状态图、以及杆件失效指标,进而定义了平面杆系结构失效包络图、结构工作状态图。又据该图中反映杆元状态的点群的分布情况,分别从概率分布、加权平均和取最大值的角度定义了三种结构整体失效指标。利用杆元和结构失效指标可简明直观地进行结构失效评估,成为与通常基于结构物理性能改变的结构损伤评估不同的另一种几何评估模式。利用本方法分析了一个三跨六层框架,计算了该框架在多种荷载、梁柱线刚度比、以及失效评估杆元划分密度下的各种失效指标。 相似文献
95.
Building enclosures contribute 10–50% of the total building cost and 14–17% of the total material mass. The direct as well as indirect influence of the enclosure materials plays an important role in the building life cycle energy. Single landed houses, the typical houses in Indonesia, have been chosen for this study. The life cycle energy of the house enclosures and energy consumed during their life spans shows intriguing results. The initial embodied energy of typical brick and clay roof enclosures is 45 GJ compared to the other typical walls and roof material (cement based) which is 46 GJ. However, over the 40 years life span of the houses, the clay based ones have a better energy performance than the cement based ones, 692 GJ versus 733 GJ, respectively. The material selection during the design phase is thus crucial since the buildings have at least 40–50 years’ life span. 相似文献
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The original unified hardening (UH) model, in which a straight Hvorslev envelope was employed to determine the potential peak stress ratio of overconsolidated soils, is revised using a smoothed Hvorslev envelope (Hermite-Hvorslev envelope). The strength at the intersection between the straight Hvorslev envelope and the critical state surface (i.e. Mohr-Coulomb envelope) can be undefined due to the discontinuous change in the slope of the two linear strength envelopes mentioned above. A smoothed Hvorslev envelope is derived through Hermite interpolation to ensure a smooth change between the proposed Hvorslev envelope and the zero-tension surface as well as a smoothed transition between the proposed Hvorslev envelope and the critical state surface. The Hermite-Hvorslev envelope is then integrated into the original UH model, and then the UH models with four different functions of the Hvorslev envelope are compared with each other. The UH model revised by the Hermite-Hvorslev envelope can well predict the mechanical behaviors of normally consolidated and overconsolidated soils in drained and undrained conditions with the same parameters in the modified Cam-Clay model. 相似文献
100.