大倾角中厚煤层软弱顶底板柔性护巷技术

在大倾角中厚煤层沿空留巷中,以往的支护方式难以满足大倾角中厚煤层巷道特殊的围岩结构稳定的需要,同时无法适应工作面内矸石垮落造成留巷困难。文章针对这一难题,首次提出并采用了"柔性护巷"技术,通过利用巷道上帮形成的由垮落矸石堆积在特制钢筋网上的"包护带",允许巷道顶板有一定的下沉量,从而使矸石充分为巷道顶板组合岩梁结构提供支撑力。在总结其施工工艺的基础上,通过现场试验,研究了巷道矿压显现规律、顶板移动规律、矸石垮落堆积规律和钢筋网变形规律;实验结果表明,在利用锚、网、索、支柱联合支护的基础上,应用"柔性护巷"技术能有效地解决大倾角中厚煤层沿空留巷技术难题。     

Novel experimental strategy for high resolution AFM imaging of membrane-associated bacterial toxins

Bacterial pore-forming toxins （PFTs） are essential virulence factors of many human pathogens. Knowl- edge of their structure within the membrane is critical for an understanding of their function in pathogenesis and for the development of useful therapy. Atomic force microscopy （AFM） has often been employed to structurally interrogate many membrane proteins, including PFTs, owing to its ability to produce sub-nanometer resolution images of samples under aqueous solution. However, an absolute prerequisite for AFM studies is that the samples are single-layered and closely-packed, which is frequently challenging with PFTs. Here, using the prototypical member of the cholesterol-dependent cytolysin family of PFTs, perfringolysin O （PFO）, as a test sample, we have developed a simple, highly robust method that routinely produces clean, closely-packed samples across the entire specimen surface. In this approach, we first use a small Teflon well to prepare the supported lipid bilayer, remove the sample from the well, and then directly apply the proteins to the bilayer. For reasons that are not clear, bilayer preparation in the Teflon well is essential. We anticipate that this simple method will prove widely useful for the preparation of similar samples, and thereby enable AFM imaging of the greatest range of bacterial PFTs to the highest possible resolution.     

城市交通规划模型的探讨

通过对中美两国城市交通模型的现状和发展的比较.首先回顾了美国在交通规划模型实践中的经验和存在的问题,并分析了中国交通问题的特征,及其交通模型的选择和数据采集方面的优势,主张中国在模型的开发和应用上,不应该局限于西方国家的实践经验,而应当大胆创新.其次,认为交通规划模型的研发,应该从提高预测能力和增强分析能力两个层面入手.当前一项紧迫的任务是由国家交通运输部组织专家工作组,对不同的模型和方法做客观的评价,为交通规划建模提供规范化的技术指导.最后,讨论了交通规划和GIS软件在实际应用中常常被忽略的一些技术问题.     

基于PLC与变频器的船用载货电梯控制系统研究

某型船用载货电梯采用PLC控制。PLC单独使用时,在控制装置在使用过程中存在一些不足,会出现运行不稳定、能耗大、噪音大等问题。通过加装变频器对某型船的PLC单独控制的系统进行系统的升级改造,介绍了基于PLC与变频器的电梯控制系统硬件组成方案及逻辑控制程序。仿真结果表明加装变频器后,电梯故障率降低,提高了电梯运行的安全性和可靠性。     

A non-geometrically similar model for predicting the wake field of full-scale ships

The scale effect leads to large discrepancies between the wake fields of model-scale and actual ships, and causes differences in cavitation performance and exciting forces tests in predicting the performance of actual ships. Therefore, when test data from ship models are directly applied to predict the performance of actual ships, test results must be subjected to empirical corrections. This study proposes a method for the reverse design of the hull model. Compared to a geometrically similar hull model, the wake field generated by the modified model is closer to that of an actual ship. A non- geometrically similar model of a Korean Research Institute of Ship and Ocean Engineering (KRISO)’s container ship (KCS) was designed. Numerical simulations were performed using this model, and its results were compared with full-scale calculation results. The deformation method of getting the wake field of full-scale ships by the non-geometrically similar model is applied to the KCS successfully.     

汽车雨水管理的数值仿真与评价

汽车在雨天行驶时,落到侧窗表面的雨水会影响驾驶员的侧向视野和后视野,从而危及行车安全,故侧窗雨水管理对于整车安全非常重要。但迄今为止对于侧窗雨水管理问题尚未有一个统一而有效的评价方法。为此,本文中应用液膜模型和拉格朗日粒子模型对某款SUV进行了雨水仿真,基于人机工程学和粒子束轨迹技术提出了侧窗雨水管理的评价方法,并对仿真结果进行了相应的分析。     

浅析K型隐藏式把手受力件材料应用及DV测试

随着近年来汽车创新发展不断兴起,汽车把手这一传统领域也推出了创新产品隐藏式车门把手.针对目前市场出现旋转式隐藏门把手断裂或折断等失效问题,提出了对于隐藏式把手总成主要受力件的塑料材料选择方案和相关塑料材料物理性能分析.又对此方案下的总成试验件进行了机械性能测试并给出结果.     

海浪与船舶安全航行

本文采用流体重力波动力学原理,分析因流体重力波引起的海面动能的传播,即海水表面质点的扰动,对航行在大风浪的船舶有一定的影响,为了使船舶在大风浪中安全、经济航行,航海人员必须了解大风浪的发生、发展和传播,并采取有效、合理的措施,保证船舶在大风浪中安全、经济航行。     

亚洲豪华游船市场发展研究

亚洲经济的发展促进了豪华游船市场的开发及发展,为此论述了亚洲豪华游船发展现状及发展原因,并对中国、韩国及日本之间豪华游船市场发展进行了展望。     

船用柴油机12PA6B超负荷性能试验研究

我国船用柴油机功率标准规定柴油机应能够在超负荷功率(即110%标定功率)下连续运转。超负荷工况各参数变化可以反映柴油机的整体性能,是船用柴油机负荷试验的重要工况点。本文通过陕柴重工生产的12PA6B柴油机的负荷试验,研究证实该机型在超负荷工况下能保持较低的燃油消耗率和烟度排放,以及较高的功率和扭矩输出。