上保护层开采底板破坏深度和应力分析研究

上保护层开采导致的底板变形、应力释放会使被保护层内高瓦斯沿着上覆岩层内形成的空隙裂隙结构向上运移，很容易造成所采工作面采空区内瓦斯增加，造成工作面瓦斯超限。以峰峰集团以黄沙矿为研究实例，针对其主采的2号煤层利用FLAC^3D模拟软件进行上保护层开采底板应力研究，揭示了上保护层开采底板应力的规律特性，对于保护层开采工作瓦斯治理具有一定的指导意义。     

Evolution of properties of parts during MIM and sintering of recycled oxide particles

Metal injection moulding (MIM) is an established process for high volume production of complex shaped metallic parts using commercially available feedstocks. The characteristics of parts after moulding, debinding, and sintering cannot be simply predictable from raw materials because the properties get altered with the process parameters and the corresponding levels of porosity during processing steps. In this study, physical properties, microstructure, and mechanical properties of the MIM parts have been characterised to understand the evolution of strength during various steps in MIM processing. Feedstocks with different binder loading show a considerable difference in physical as well as mechanical characteristics. During sintering of parts which have solid loading of grinding sludge, simultaneous in situ reduction and densification takes place, whereas only densification occurs in carbonyl iron parts. It is, therefore, possible to make complex shaped parts of different levels of porosity from downgraded shop floor metallic waste.     

Evaluation of standard and real fire exposures on thermal response of rail car floor assembly

This work developed a computational methodology to evaluate and compare standard fire exposures such as those outlined in ASTM E119 with real fire exposures and determine the difference in the temperature rise of a rail car floor assembly. The real fire exposures simulated in this work were identified in a review of incidents and consisted of a constantly-fed diesel fuel spill, a localized trash fire, and a gasoline spill simulated from a collision of the railcar with an automobile. These realistic fire exposures were applied to a variety of exemplar rail cars representative of single-level and bi-level passenger cars. These floor assembly models exposed to realistic fires were simulated in Fire Dynamics Simulator (FDS). The thermal exposure at the underside of railcar provided by FDS was coupled with a thermal model in ABAQUS, which provided the evolution of temperature in different components of the floor assembly. The standard scenarios were simulated for 2 hours instead of the typical 30 minutes to identify the appropriate exposure duration in ASTM E119, which can better represent a real fire scenario. The average and maximum temperatures predicted at the unexposed surface for both scenarios were compared with the threshold values given in NFPA 130.     

地源热泵——辐射地板联供试验

通过地源热泵－辐射地板系统冬夏联供试验，讨论了该系统作为新型环保节能空调方式的可行性及优越性，并对运行中出现的问题进行分析。     

Research on Marine Boiler＇s Pressurized Combustion and Heat Transfer

The effect of pressure on combustion and heat transfer is analyzed. The research is based on the basic combustion and heat transfer theorem. A correction for the heat calculation method for pressurized furnace is made on the basis of the normal pressure case. The correction takes the effect of pressurizing into account. The results show that the correction is reasonable and the method is applicable to combustion and heat transfer of the marine supercharged boiler.     

无粘结预应力楼板新规范设计方法

目前国内现浇预应力楼板几乎均采用无粘结预应力方案,因而掌握其设计方法无疑具有现实意义。本文根据新规范,系统地介绍了高层建筑无粘结预应力楼板的设计方法,内容包括:设计原理、基本步骤及设计中需要注意的一些问题。     

垂直平行束状孔爆破模型试验与分析

垂直平行密集束状孔落矿有底柱崩落法是一种新的采矿方法。通过爆破模型试验，测试爆破应力，观察分析爆破效果，探求最佳布孔形式，选择最优爆破孔网参数。试验结果表明：用平行束状孔取代扇形落矿，改善了爆破效果，简化了采场结构，减少了采切工程量。     

砖混结构现浇楼板的裂缝分析及预防措施

针对目前多层住宅采用砖混结构现浇钢筋混凝土产生裂缝的情况，分析了其产生原因，提出了预防措施。指出这些预防措施可使裂缝得到有效控制。     

大跨度钢桁架桥的施工与实践

介绍了天生桥一级水电站引水道进水塔大跨度钢桁架桥施工的全过程，包括制作，运输、安装、试验等几个部分，以供类似工程施工参考。     

《燃气红外线辐射供暖系统设计选用及施工安装》国家标准图集介绍

介绍了该国家标准图集的主要内容：设计说明、典型设计、工程实例、系统设备、燃气管道安装、液化石油气气化站、电气控制及温度检测、施工安装说明。