混凝土简支梁预设变形值探讨

以某高速公路钢筋混凝土与预应力混凝土工程为例，从简支梁的预拱度和下挠度的设置两方面进行了阐述，提出了钢筋混凝土简支梁下挠变形和预应力混凝土简支梁上拱变形的不同之处。     

水价提高对天津市水资源需求量的影响分析

针对天津市用水现状,运用价格弹性理论分析了天津市需水量变化与提高自来水价格之间的定量关系,提出了水价调整方案,并对方案实施的结果进行了相应的预测.     

Flow of solutions of hydroxypropyl guar-poly(ethylene oxide) mixtures through a porous medium

Summary In flow through porous media, solutions of poly(ethylene oxide) (PEO) exhibit extension thickening, whereas hydroxypropyl guar (HPG) solutions are shear-thinning at high concentrations. The results show that the extension-thickening exhibited by PEO solutions becomes less critical with increasing flow rate as the concentration of HPG in the solution is increased. At high concentrations of HPG, the presence of PEO inhibits the shear-thinning behaviour, without increasing the apparent viscosity of the solution. The presence of HPG reduces the rate and extent of degradation of PEO in the flowing solution.     

A methodology for investigating effects of cell size on operational flexibility in flexible manufacturing systems

There are two aspects to cell formation in flexible manufacturing systems, cell sizing or deciding on the optimum number of machines to be allocated to each cell, and then allocation of specific machines to each cell. Although the latter problem has been investigated extensively there is a paucity of published work on the former. This paper discusses the effects of cell sizing on operational flexibility.Operational flexibility is that aspect of flexibility that enables manufacturing systems to respond with speed and efficiency to changes in the manufacturing environment while maintaining an effective level of control.     

Modulation of the enzymatic activity of papain by interdomain residues remote from the active site

The two main catalytic residues Cys25 and Hisl59 of the monomericcysteine protease papain are located on different walls of acleft formed by two domains. This topology suggests a possiblerelationship between relative domain organization and catalyticmechanism. The effect on enzymatic parameters of structuralmodifications at various locations of the twodomain interfaceof papain was examined by individual or double replacementsby Ala of pairs of interacting residues. Most modificationshad no effect on enzyme activity. However, the enzyme's substrateturnover (k_cat) decreased following simultaneous alterationof the two most conserved residues, forming an apolar contactlocated 15 Å away from the active site. The pH activityprofile of the double mutant was unchanged, indicating a conservedionization state of the active site thiolate-imidazolium ionpair. This state is strongly dependent on the distance separatingthe two residues, thus suggesting that the active site geometryhas not been significantly altered. Efficient enzymatic activityin papain requires more than a correct active site geometryand is influenced by domain packing properties in a region remotefrom the active site.     

新疆叶尔羌河中游渠首工程地基处理设计

叶尔羌河洪水动态规律极为复杂,以其极高的起涨速率、异常的高洪峰值闻名于世。中游渠首地基是粘粒极少、极松散的粉细沙层。针对其特点,采用振冲挤密砂石桩、防渗防冲连续墙、抗冲柔性土工布金属网格石笼等综合处理措施进行设计。     

支持状态机建模的工作流引擎研究

为了能清晰地描述存在较多审批环节和步骤跳转的业务流程,提出利用状态机为流程建模的方法。通过改进传统的关系结构工作流引擎,给出一个支持状态机建模的关系结构工作流引擎的设计方案,详细介绍该引擎的设计原理和实现柔性方法。最后通过一个示例,演示支持状态机建模的工作流引擎的工作机制和实例迁移的过程。原型已经应用到高校学费管理系统中。实践证明,该引擎可以有效地支持状态机建模,并缩短关键业务的开发周期。     

膨胀弯管在管道柔性设计中的定性分析

为防止管道因热胀冷缩、管道支撑或端点附加位移造成的应力问题,对管线中设置的膨胀弯管进行定性分析.通过2个参数的变化对膨胀弯管进行编号得到多种设计方案,用ANSYS建立管道的有限元模型,并分析各方案中膨胀管道的变形、应力和弯矩等;根据分析结果对膨胀弯管设计半径、设置位置和形状进行定性分析.该定性分析结果可为膨胀弯管概念设计和管道柔性设计提供参考.     

柔性基电磁屏蔽材料的研究进展

本文介绍了电磁屏蔽材料的屏蔽原理、电磁屏蔽损耗材料的类型及性能,总结了柔性基电磁屏蔽材料的制备方法及其研究进展。     

面向主动需求响应的需求侧荷源二重性建模方法

以面向主动需求响应的荷源二重性建模方法为主题,从需求侧灵活性资源参与电网调度的视角分析了国内外在荷源二重性建模方面的研究成果,按照研究对象划分,负荷跟随电源（load-follows-generation, LFG）模型分为一般负荷、储能设备、分布式能源及其组合,对负荷响应建模、优化目标、约束条件、调度方法、控制方式等进行阐述,阐述了负荷跟随发电的模式能够实现主动需求响应,优化负荷曲线,缓解发电侧调度压力,促进可再生能源消纳。