城市天然气管网系统抗震能力空间分析与评价模型研究

城市天然气管网系统的抗震能力直接影响着城市震害防御的总体性能和震害的损失程度，对其进行抗震能力评价是城市制定防震减灾决策的重要依据。为此，借助于地理信息系统在空间数据处理上的技术优势，集成确定性分析方法，在对天然气管网系统进行空间网络模型化的基础上，以天然气管道的应力值作为评估量，以组合应力作为管网单元震害破坏程度的判断标准，构建了城市管网系统抗震能力空间分析与评价模型。该模型实现了对城市天然气管网系统在空间地域上的抗震能力分析与评价并得到了可靠的评价结果；实现了对评价结果数据的空间直观展示与定位查询分析，为决策者在震前及时掌握天然气管网系统中各管段的抗震能力及震害破坏程度提供了便捷。该模型的建立，为城市的震害防御提供了可靠的模型支持、技术支持及数据支持。     

GENERATION OF NONLINEAR INTERNAL WAVES ON CONTINENTAL SHELF

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＩｎｔｅｒｎａｌｔｉｄａｌｉｎｔｅｒａｃｔｉｏｎｗｉｔｈｂｏｔｔｏｍｆｅａｔｕｒｅｓａｐｐｅａｒｓｔｏｂｅｔｈｅｄｏｍｉｎａｎｔｍｅｃｈａｎｉｓｍｆｏｒｇｅｎｅｒａ ｔｉｏｎｏｆｔｈｅｃｏｈｅｒｅｎｔｏｃｅａｎｉｃｉｎｔｅｒｎａｌｗａｖｅｓｔｈａｔａｒｅｏｂｓｅｒｖａｂｌｅｗｉｔｈＳＡＲ ,ｃｌｏｓｅｒｔｏｓｈｏｒｅ ,ｒｉｖｅｒｉｎｅｏｒｇｌａｃｉａｌｉｎｔｒｕｓｉｏｎａｎｄｃｏｎｔｉｎｅｎｔａｌｂｒｅａｋｐｒｏｖｉｄｅｓｅｃ ｏｎｄａｒｙｇｅｎｅｒａｔｉｎｇｍｅｃｈａ…     

基于条码扫描的特种冰箱集存库系统设计与应用

本文将条码扫描器应用于特种冰箱的制造中,建立了一种新型全自动集存库系统,重点分析了本系统的工作原理和硬件配置,及PLC的程序设计和触摸屏组态软件设计。     

Charge transport and luminescent properties of PMMA-dehydrate nanotubed titanic acid nanocomposites

In this paper, we doped p-type conductivity dehydrated nanotubed titanic acid (DNTA) into insulator polymer poly(methyl methacrylate) (PMMA). The electric properties of this nanocomposite were investigated. The photoluminescence efficiency of fluorescent dye 4-(dicyanomethylene)-2-t-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) in PMMA matrix was enhanced by doping with DNTA. Moreover, screen effect by DNTA with high permittivity caused the emission from DCJTB to be blue-shifted.     

酮亚胺对水性聚氨酯性能的改进

用丙酮分别和乙二胺、己二胺反应制备酮亚胺,并以其作为潜伏性扩链剂改善水性聚氨酯(PU)的性能。研究了酮亚胺以不同方式、加量对水性PU漆膜的厚度、硬度、耐水性、耐酸性、热稳定性和机械性能的影响。结果表明,采用丙酮缩乙二胺扩链的水性PU乳液的漆膜的耐水性优于用丙酮缩己二胺和用水扩链的PU乳液的漆膜,且加入过量的酮亚胺扩链效果较好,但其热稳定性并没有得到明显提高。     

Extended Graetz problem including streamwise conduction and viscous dissipation in microchannel

Extended Graetz problem in microchannel is analyzed by using eigenfunction expansion to solve the energy equation. The hydrodynamically developed flow is assumed to enter the microchannel with uniform temperature or uniform heat flux boundary condition. The effects of velocity and temperature jump boundary condition on the microchannel wall, streamwise conduction and viscous dissipation are all included. From the temperature field obtained, the local Nusselt number distributions are shown as the dimensionless parameters (Peclet number, Knudsen number, Brinkman number) vary. The fully developed Nusselt number for each boundary condition is obtained also in terms of these parameters.     

Sensor fault tolerant control using sliding mode observers

Previous work has considered the use of sliding mode observers for fault detection and isolation (FDI) in uncertain linear systems whereby the unknown faults are reconstructed by appropriate processing of the so-called equivalent output error injection. The paper builds on this work and considers such a scheme within the broader context of fault tolerant control. Specifically, by correcting the faulty measurement by an estimate of the fault obtained from the sliding mode FDI scheme, good closed-loop performance is still maintained. An example of such a scheme, which has been implemented in real-time on a laboratory dc motor rig, is described.     

Epoxidation of high trans‐1,4‐polyisoprene and its properties

A new organic‐solvent‐free water‐phase suspension method was used to synthesize partially epoxidized high trans‐1,4‐polyisoprene (TPI) to improve its properties, including oil resistance and wet‐skid resistance. The epoxidation was conducted in an aqueous peracetic acid solution and on the TPI granules prepared by a bulk precipitation method with supported titanium catalyst. The effects of the synthesis conditions, including reaction temperature, reaction time, and pH value, on the epoxy content were investigated. Epoxidized trans‐1,4‐polyisoprene (ETPI) with epoxy contents between 10 and 80% were obtained within 4 h. Both the amorphous and crystalline regions of TPI were epoxidized. The crystallization properties decreased with increasing epoxy content. ETPIs possessed lower mechanical properties than TPI but could be enhanced by vulcanization. The oil resistance and wet‐skid resistance were significantly improved after epoxidation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Negative selection based immune optimization

An immune optimization algorithm is proposed in this paper based on the immune negative selection. The algorithm NSIOA is motivated by the negative selection mechanism in biological immune recognition. Different from the existing immune optimization methods, NSIOA constantly removes the worst solutions to get the optimal solution. Considering that removal of poor members of a population might lead to the loss of design information that may actually help identify better solutions in the search space, the proposed NSIOA is designed to keep the diversity of antibodies while removing poor members, therefore the algorithm will converge to global optimal solution with high probability. The convergence property and the complexity of the algorithm have also been analyzed. To illustrate the efficiency of the algorithm is used in solving the travel salesman problem. The theoretical analysis and experimental results show that the algorithm is of a strong potential in solving practical problems.     

Enhanced Ruiz criterion for the evaluation of crack initiation in contact subjected to fretting fatigue

The fatigue-fretting damage parameter (FFDP) introduced by Ruiz is comprehensively discussed in this paper. Shortcomings and limitations of this criterion are presented resulting in a combined energetic-multiaxial enhancement (eFFDP). Specific frictional power was supposed to control the fretting damage and the critical plane approach is used to solve the multiaxial stress state in the fretting contact. The significance of the eFFDP is evaluated for the key–shaft–hub connection under combined torque and bend loading. Applying the analysis to recent fatigue tests, a comparison of stress and fretting parameters is made for different loading conditions including estimation of the fretting fatigue limit.