基于整体承载极限状态的钢结构可靠度设计方法及其在门式钢刚架设计中的应用

本文提出了基于整体承载极限状态的钢结构可靠度设计思路。这种思路建立在钢结构整体非线性分析和验算的基础上,并确保结构整体而非构件的可靠度水平,使结构整体的实际可靠度水平尽可能地接近于设计的目标值。本文针对门式钢刚架结构建立了一套实现这种设计的方法,包括结构整体非线性分析、结构体系可靠度计算以及实用的设计表达式。通过三个门式钢刚架结构设计实例比较了传统的构件设计方法,不考虑体系可靠度的整体承载极限状态设计方法和本文考虑体系可靠度的整体承载极限状态设计方法的设计结果,说明本文所提出设计思想的先进性。     

Probabilistic Modelling in the Water Industry

The water authorities in England and Wales, which have now become water companies, recently had to provide anticipated costs for maintaining the water supply and sewerage systems over the next 20 years. Probabilistic models and statistical inference provide an opportunity to quantify the uncertainty in such exercises. Their use in a study undertaken by a water authority in the north-east of England is described and illustrated with interim data which were available at an early stage in the exercise.     

混凝土结构火灾后的检测方法研究

本文通过对混凝土结构火灾后的火场温度确定分析以及不同方法检测火灾后混凝土的强度试验，系统地研究了混凝土结构在遭受火灾后的检测方法．提出了一些有效的检测手段。     

概率修整在卷材生产线调整中的应用

通过一个案例,介绍了利用概率修整的方法来判断卷材生产线调整正确与否,从而为采取相应的措施提供依据。     

突发事故中结构易损性的研究

易损性是指系统容易受到伤害或损伤的程度,世贸大厦的倒塌,使得结构易损性问题在土木工程领域引起了广泛关注.本文用结构倒塌分析程序对天津第二毛纺厂中南楼结构中各构件的重要性进行了分析,并对国内外结构易损性研究进行了分析和展望.     

浅谈工程量清单计价

对工程量清单计价在工程造价管理中的重要作用及编制方法进行了明确地阐述 ,指出我国加入WTO后 ,原有工程价格的形成体系会受到很大冲击。推行工程量清单计价是深化工程造价管理的重要举措 ,也是与国际接轨所需要的     

Organophosphate and phthalate esters in air and settled dust - a multi-location indoor study

This paper reports the abundance in indoor air and dust of eleven organophosphate esters and six phthalate esters. Both groups of these semi-volatile compounds are widely incorporated as additives into plastic materials used in the indoor environment, thus contributing to indoor exposure to industrial chemicals. Thirty sampling sites representing three different indoor environments (private homes, day care centers, and workplaces) in the Stockholm area, Sweden, were selected to obtain representative concentration profiles in both ambient air and settled dust. Eight of the target organophosphate esters and all six phthalate esters were found in both air and dust samples at all locations. The phthalate esters were more abundant than the organophosphate esters, typically ten times higher total concentrations. Especially interesting were the high levels of tributoxyethyl phosphate in the day care centers, the relatively high levels of chlorinated organophosphate esters in the air of workplaces and the overall high levels of diethylhexyl phthalate in dust. The air concentration profiles of the phosphate esters differed significantly between the three indoor environments, whereas the concentration profiles of the phthalate esters as well as their total concentrations were similar. The correlation between concentrations found in air and in dust was found to be weak. PRACTICAL IMPLICATIONS: Organophosphate esters and phthalate esters are commonly used as additives in numerous building materials and consumer products. The use of these compounds is increasing, and phosphate and phthalate esters are to be regarded as ubiquitous contaminants in the indoor environment. These compounds comprise a number of different compounds that have been associated with biologic effects in animal studies as well as in humans. Thus, it is of concern to increase the knowledge about human exposure of these compounds because of their presence in indoor air. In this paper, thirty indoor environments have been surveyed with respect to seventeen of the most abundant of these compounds.     

泛滥平原沉积物的超低密度采样代表性研究(二):统计学检验及地质意义

设计了１个采样点／１ｋｍ２、１个组合样／４ｋｍ２，１个采样点／１００～１０００ｋｍ２和１个采样点／１０００～１００００ｋｍ２３个层次的采样密度，系统研究了泛滥平原沉积物的超低密度采样代表性。运用统计学原理对泛滥平原沉积物中３０～４０余种元素进行正态母体显著性检验、ｔ检验及对多元素总体的灰关联分析，表明用１个采样点／１０００～１００００ｋｍ２的采样密度采集的泛滥平原沉积物具有代表性。因此建议在国际地球化学填图中用泛滥平原沉积物作为全球超低密度地球化学填图的采样介质。     

三维图像栈中神经末梢点的自动检测

作为神经元追踪算法的种子点,神经元的末梢点的检测非常关键。此前的研究提出了一种基于发散射线模型(rayshooting model)的检测方法,通过分析神经元图像中候选末梢点附近邻域的灰度强度分布来检测神经元的末梢点。然而,在此模型中,射线的长度以及z方向切片的数量都是固定值,所以在处理一些神经元直径尺寸变化较大的图像时,算法的准确性很受影响。因此,提出了一种可以根据神经元局部直径大小来改变射线长度以及相邻切片数量的自适应发散射线模型,神经元的局部直径由一种结合了Rayburst sampling算法及MSFM(multistencils fast marching)算法的方法测得。实验结果表明,与之前的方法相比,检测精度提高了约10%。     

基于变采样周期的CPS多重优先级调度研究

信息物理融合系统(CPS)是实现能源互联网中信息技术和电网技术融合的重要技术体系。针对在CPS中采用传统调度策略导致的高丢包率、低利用率和网络延时长等问题,提出了一种多重优先级的调度策略,该调度策略能够保证信息在网络中传递的灵活性;基于该调度策略,针对CPS不同组成部分的特点,提出了两种变采样周期算法,该算法能够同时兼顾网络资源情况和系统控制性能,使系统在网络资源受限的情况下能够达到稳定状态。最后,根据能源互联网的特点,描述了如何将该调度策略应用于能源互联网中。