城市燃气管道内检测技术

分析了管道内检测的必要性,介绍了基于无损检测理论的漏磁检测、超声波检测、射线检测、涡流检测以及红外热成像检测等管道内检测技术,探讨了漏磁检测技术在城市燃气管道中的应用,提出了加强管道完整性管理的建议。     

液化石油气中加臭剂的检测与控制

论述了对液化石油气中加臭剂进行检测的必要性,介绍了加臭剂的检测方法和仪器选择。结合加臭剂检测的实践,探讨了加臭剂的控制措施。     

基于小波包变换的长周期结构高频地震动瞬态反应研究

高频地震动对长周期结构的影响往往不被重视,结构瞬态振动的作用通常被忽略。借助小波包分解,以简谐地震反应为理论基础进行多自由度体系在实际地震动作用下的瞬态反应计算。通过长周期和短周期结构工程实例的瞬态反应计算,揭示了长周期结构在高频地震动作用下的瞬态振动规律。研究结果表明,结构在低阶振型的振动位移主要受瞬态反应的影响;长周期结构在高频地震动作用下随建筑物高度的增加,瞬态振动的影响愈加显著。因此,高频地震动作用下,长周期结构的瞬态振动不能被忽略,其最大值甚至超过结构在地震激励期间所发生的共振位移,由此提出以结构基本自振频率与激震频率之比值作为划分长、短周期标准的建议。     

地铁与建筑物合建中不同固有频率钢弹簧浮置板轨道的适用性分析

以基于车辆-轨道耦合动力理论的地铁-钢弹簧浮置板耦合动力模型为基础,按照钢弹簧底座位置上力相互协调的原则,建立隧道-建筑物-地基二维有限元模型。然后从分析合建结构的自振特性和钢弹簧支反力的频谱特征入手,采用1/3倍频程振级评价法探讨不同固有频率钢弹簧浮置板轨道在不同合建结构形式中的适用性。研究结果表明:①地铁与建筑物合建结构的竖向自由振动20～80Hz的参振质量比例较高,可达50%以上,而4～10Hz竖向参振质量却差异较大,这与结构尺寸和刚度有关;②4～10Hz钢弹簧浮置板都可有效削减合建结构20～80Hz的竖向振动能量,但会放大浮置板固有频率附近的振动能量;③地铁低频振动传播容易在合建结构内引起共振,因此钢弹簧浮置板固有频率应避开合建结构4～10Hz内竖向参振质量较大且较集中的频段。     

幕墙中空玻璃失效在线检测技术

针对幕墙中空玻璃中空层气体泄漏并导致其节能功能失效及外片脱落质量事故问题,研究中空玻璃中空层密封性能在线检测技术及装置。根据中空玻璃的承载特性,给出集中载荷作用下中空玻璃在中空气体层密封和泄漏状态下的中空玻璃内、外片变形量理论计算方法。理论和试验研究揭示相同载荷作用下中空层失效后改变中空玻璃的变形性能,失效后中空玻璃承载面变形明显增大,而另一面玻璃几乎不变形,且整体承载能力明显降低。基于此现象,提出采用在中空玻璃面板中心施加集中荷载,并通过观测中空玻璃内、外片变形量的大小或中空层的厚度变化来评价中空玻璃中空层的密封性能。通过一个实施例,描述该方法的实施过程,验证该方法的实用性和可靠性。     

混凝土结构扣件式钢管模板高支撑体系现场检测和分析

现场监控整个施工过程中支撑架轴力的变化,是确保模板高支撑体系安全的一种有效方法。通过对某工程高支撑体系的现场检测试验,研究混凝土浇筑过程泵管的周期性冲击作用、混凝土振捣棒的振动作用以及混凝土浇筑路线等因素对高支模架体系的轴力影响,揭示混凝土振捣棒对高支模架的受荷影响范围和大小,以及高支模架所受的动态轴力和静态轴力的关系。     

某中学教学楼抗震鉴定及加固

上海市某中学教学楼建于1983年,原设计按6度抗震设防,存在明显不符合现行抗震规范的问题.为保证校舍继续安全使用,进行原始资料调查、现场检测及结构抗震性能评定,根据评定结果提出相应的加固方案.加固后的结构基本达到重点设防类抗震设防标准,结构整体性及承载力得到显著提高,从而改善了结构的安全状况.     

Transient thermo-mechanical coupling simulation of wet brake friction disk on tracked vehicle

The transient finite element technique is applied,and a transient heat conduction model of wet brake friction disk is established.For obtaining the accurate heat-flow density mathematic model and avoiding possibly instable thermoelastic stress produced by the non-uniform contact pressure of friction pair,a test method is applied to collect accurate contact pressure between the dual sheet steel and friction disk in the combining process.And then the heat-flow density and transient thermo-mechanical coupling simulation are analyzed.At the same time all possible boundary conditions are considered,such as the heat generation,heat conduction problem,relation between friction and contact,variation in load and heat change problem etc.The simulation results show that the mechanical model of thermo-mechanical coupling can express well the dynamic characteristics of friction disk,and gives perfect reference for more study on thermoelastic distortion of brake friction pairs.     

Perceptual and decisional factors influencing the discrimination of inversion in the Thatcher illusion.

The Thatcher illusion (Thompson, 1980) is considered to be a prototypical illustration of the notion that face perception is dependent on configural processes and representations. We explored this idea by examining the relative contributions of perceptual and decisional processes to the ability of observers to identify the orientation of two classes of forms—faces and churches—and a set of their component features. Observers were presented with upright and inverted images of faces and churches in which the components (eyes, mouth, windows, doors) were presented either upright or inverted. Observers first rated the subjective grotesqueness of all of the images and then performed a complete identification task in which they had to identify the orientation of the overall form and the orientation of each of the interior features. Grotesqueness ratings for both classes of image showed the standard modulation of rated grotesqueness as a function of orientation. The complete identification results revealed violations of both perceptual and decisional separability but failed to reveal any violations of within-stimulus (perceptual) independence. In addition, exploration of a simple bivariate Gaussian signal detection model of the relationship between identification performance and judged grotesqueness suggests that within-stimulus violations of perceptual independence on their own are insufficient for producing the illusion. This lack of evidence for within-stimulus configurality suggests the need for a critical reevaluation of the role of configural processing in the Thatcher illusion. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

食源性真菌毒素检测技术研究进展

本文分析了真菌毒素致病机理及危害,评述了真菌毒素检测技术与方法,了解和掌握了真菌毒素检测技术研究的进展,阐述了加强我国真菌毒素检测技术研究的重要性,为建立准确、快速、简便的检测技术体系提供了依据.