扣件式钢管满堂支撑体系稳定性的有限元分析及试验研究

通过对大量不同搭设参数下满堂支撑体系进行考虑初始缺陷及直角扣件半刚性性质的有限元分析,定量地分析步距、立杆间距、最小搭设跨数、立杆伸出顶层水平杆的长度、剪刀撑设置方式等一系列因素对满堂支撑体系承载力的影响。对满堂支撑架与满堂脚手架这两种受力机理不同的支架体系力学性能进行研究,并进行一系列超高满堂支撑架及脚手架的原型试验。通过将各种方法计算所得结果进行对比,指出原《建筑施工扣件式钢管脚手架安全技术规范》(JGJ 130—2001)中对于模板支架的计算方法存在一定不足。总结对满堂支撑体系的有限元及试验研究成果,并结合对规范(JGJ 130—2001)的修订工作,进而提出满堂支撑体系稳定性承载能力计算方法一系列改进。     

兰州某地铁站蒸发冷却通风降温系统测试与应用研究

介绍了兰州某地铁站蒸发冷却通风降温系统,通过对该系统中机组进出风温度、站厅站台公共区环境温湿度、空气品质的实际测试,分析出该系统在实际运行过程中的情况.同时,对该系统中现存的一些问题,进行了分析说明,并提出了后期的优化改进措施.最终的测试结果表明,该蒸发冷却通风降温系统的运行情况较好,车站内公共区的降温效果良好,为以后...     

预应力索拱体系在包头一机展览馆中的应用

通过预应力索拱体系在包头一机展览馆中的应用,对索中预应力值的确定、索张拉方式的选择以及索节点的处理作了一定的探讨;同时比较了预应力索拱体系和拱-柱体系的特点。分析结果表明,索拱体系的采用使得工程的用钢量大大减少。由于工程设计与施工紧密结合,使设计合理,施工也大大简化。     

构筑实现梦想的舞台——惠州市金山湖游泳跳水馆设计

通过对惠州市金山湖游泳跳水馆设计项目概念设计及技术设计的介绍,阐述现代游泳跳水馆的设计理念,分析独特的结构形式与空间的内在关系。     

不同气候区的汽车展厅热回收装置设置的合理性分析

为了研究处于不同气候区的汽车展厅新风机组设置排风热回收装置的合理性,以赤峰、北京、重庆、广州和昆明的汽车展厅作为实例,采用全年逐时动态计算方法进行经济性分析。结果表明,严寒和寒冷地区设置排风热回收装置时节能效果明显,夏热冬冷地区效果不甚明显,夏热冬暖和温和地区效果相对较差。     

基于智能图像处理和三维建模技术的特高压换流阀厅用套管运行状态监测方法

从智能图像处理和三维造型技术的角度提出一种针对特高压换流阀厅用套管运行状态特征的监测方法。该方法主要包括:应用智能图像处理技术对红外热像仪、紫外成像仪数据库进行辨识、分类处理;通过Kalman滤波技术针对典型金具绝缘距离进行实时在线测量;应用基于有限元法三维造型技术建立阀厅典型主设备套管的电场模拟模型,获得关键金具表面电场分布情况。结合图像数据库信息、绝缘距离信息和典型主设备套管电场分布信息有效获取其运行状态参量,并应用智能算法对其运行状态进行自动评估。结果表明:未使用Kalman滤波技术时,在0～160 s内对于关键位置处的距离预估偏差跳变较为剧烈,使用Kalman滤波技术后预估偏差跳变幅度缩小,基本控制在同一误差水平;神经网络具有较好的学习效果,适应度函数迭代100次后趋于稳定,且模糊神经网络局部权值出现较为典型的非线性特征。研究结论可有效发掘潜伏性隐患、定位正发性故障,为主设备套管运行维护提供有效的数据支撑和保护策略。     

开关磁阻电机中霍尔位置传感器细分电路

介绍了一种开关磁阻电机用的霍尔位置传感器细分电路。霍尔位置传感器磁环的加工精度是影响位置检测精度的主要原因,尤其是多转子极数的开关磁阻电机,霍尔位置传感器的磁环中磁块份数较多,这样磁环的制造成本大大增加,精度也难以保证。提出的细分电路,能减少磁环中磁块份数,降低制造成本,提高位置检测精度。     

Detection of Nontrivial Topology Driven by Charge Density Wave in a Semi-Dirac Metal

The presence of electron correlations in a system with topological order can lead to exotic ground states. Considering single crystals of LaAgSb₂ which has a square net crystal structure, one finds multiple charge density wave transitions (CDW) as the temperature is lowered. Large planar Hall (PHE) signals are found in the CDW phase, which are still finite in the high-temperature phase though they change sign. Optimizing the structure within first-principles calculations, one finds an unusual chiral metallic phase. This is because as the temperature is lowered, the separation between the Ag/Sb atoms on different layers decreases, leading to stronger repulsions between electrons associated with atoms on different layers. This leads to successive layers sliding with respect to each other, thereby stabilizing a chiral structure in which inversion symmetry is also broken. The large Berry curvature associated with the low-temperature structure explains the low-temperature PHE. At high temperature, the PHE arises from the changes induced in the anisotropic Dirac cone in presence of a magnetic field. This work represents a route toward detecting and understanding the mechanism in a correlation-driven topological transition through electron transport measurements, complemented by ab-initio electronic structure calculations.     

Heat transfer rotating MHD two-liquid slip flow regime with Hall current

In this paper, we examine the effect of thermal radiation on rotating magnetohydrodynamic two liquid flows of ionized gasses past horizontal channel under slip and Hall conditions. The fluids in the two zones are considered to be immiscible, incompressible, and electrically conducting with various viscosities, thermal and electrical conductivities. We derive the exact solutions for the temperature profiles and coefficients of heat transfer rate at the plates in the two zones by solving governing equations in the presence of slip-regime analytically. The temperature fields have been figured for various sets of values of the involved governing characteristics to analyze the behavior of heat transport. It has been noted that there is an enhancement in the temperature profile as the slip parameter rises for fixed values of the remaining parameters. Also, stimulations occur in the temperature field, with an increment in Taylor's number. This study may have some significant implementations in biomedical science such as destroying cancer cells during the drug delivery treatment, polishing damaged internal cavities, heart valves, and so forth.