砂轮线速度对CBN砂轮磨损影响的磨削试验研究

通过用陶瓷结合剂CBN砂轮对45淬硬钢工件进行磨削试验，深入分析了砂轮线速度对砂轮磨损的影响，获得能够进行高速高效磨削的合理砂轮线速度。     

Effects of process-control agents on mechanical alloying of nanostructured aluminum alloys

The effects of the process-control agents (PCAs) stearic acid and methanol on the mechanical alloying (MA) of a nanostructured aluminum alloy (Al₉₃Fe₃Ti₂Cr₂) have been investigated. The dependency of the powder-particle sizes, grain sizes, atomic-level strains, lattice parameters, formation of solid solutions, and microstructural evolution of the aluminum alloy on the types of PCAs and their concentrations have been studied using a variety of analytical instruments including X-ray diffraction scanning electron microscopy, and transmission electron microscopy. The results clearly indicate that prevention of excessive cold welding of Al particles can be achieved by the addition of a PCA at the expense of reductions in the grain size, formation rate of solid solutions, and rate of microstructural refinement, all of which are desired in MA of the Al alloy. Furthermore, a PCA that is more effective in preventing excessive cold welding will also impose more hindrance to the MA process. These phenomena have been discussed in the light of the adsorption of the PCA on the metal surface and the lubricating function of the PCA.     

Aerostatic Reliability Analysis of Long-Span Bridges

The response surface Monte Carlo method (RSMCM) is proposed for reliability analysis of aerostatic response and aerostatic stability for different types of long-span bridges, in which the nonlinear effects due to geometric nonlinearity and deformation-dependent aerostatic loads are taken into consideration. The geometric parameters, the material parameters, and the aerostatic coefficients of the bridge girder are regarded as random variables in the proposed method. RSMCM has higher accuracy in comparison with the traditional response surface method and requires much less computational cost than the conventional Monte Carlo method. The proposed method is applied to reliability analysis of aerostatic response and aerostatic stability of the Hong Kong Ting Kau Bridge, and reasonable results illustrating effectiveness of the method are obtained.     

Hot Compression Mechanical Behavior of Solution Heat-Treated and Pre-aged Mg-Zn-Gd-Er Alloys

The mechanical behavior of solution heat-treated and pre-aged Mg-6Zn-1Gd-1Er alloys during hot compression (from 180 to 330 °C) has been investigated. The results showed that the flow stress curves of the pre-aged sample (PAS) intersected with that of the solution heat-treated sample (SHTS) during hot compression. At 180 °C, when the true strain is 0.27 and 0.47, the PAS showed larger and smaller stress (210.80 MPa vs. 207.58 MPa and 205.67 MPa vs. 207.93 MPa) than the SHTS, respectively. These phenomena were due to the stronger interaction of W phase and dislocations/twins under the strain of 0.27, while dynamic recrystallization softening occurred under the strain of 0.47. When the temperature increased to 330 °C, the flow stress of PAS and SHTS showed an opposite trend to that of 180 °C. Continuous dynamic recrystallization and particle stimulated nucleation based on slip operations are the main deformation mechanisms under 330 °C. At the true strain is 0.33 and 0.53, the PAS has smaller and larger stress (61.32 MPa vs. 63.69 MPa and 58.75 MPa vs. 57.09 MPa) than the SHTS, respectively. The increasing deformation resistance of dynamic precipitation improved the flow stress under smaller strain and dynamic recrystallization decreased the flow stress under high strain, which resulted the opposite phenomena of SHTS.     

淘汰落后产能优化产品结构走新型钢铁工业发展道路——中国钢铁工业协会常务副会长罗冰生2006年11月14日在钢管分会第四届三次会员代表大会上的讲话(节选)

通过各钢管生产企业和广大职工的共同努力,2005年我国钢管产量达到2 781.12万t,成为全球钢管生产大国,产品质量明显提高,产品结构优化见成效,国际竞争力提高,我国已连续3年成为钢管净出口国.同时,钢管生产企业经营状况明显好转,盈利水平显著提高.     

考虑爆燃气体滤失和多裂缝的复合射孔裂缝扩展动态模拟

裂缝几何尺寸参数的准确预测是复合射孔优化设计和增产增注效果评价的前提条件,在复合射孔实施过程中,爆燃气体滤失和多裂缝会对裂缝扩展形态产生影响.在分析中外爆燃气体驱动裂缝扩展数学模型的基础上,结合流体力学、弹性力学和线弹性断裂力学理论,建立了全面考虑爆燃气体滤失和多裂缝的复合射孔裂缝扩展数学模型,通过假设与多个变量相关的裂缝内爆燃气体压力分布函数,利用迭代法实现了模型的数值耦合求解,获得了裂缝几何尺寸随时间的动态变化规律.实例计算结果表明:地层渗透率和裂缝条数对复合射孔裂缝扩展形态影响很大,缝长随地层渗透率和裂缝条数的增加而减小;不考虑爆燃气体滤失和多裂缝导致计算得到的缝长偏大,且相对误差随地层渗透率和裂缝条数的增大而增大.     

大型LNG地上全容储罐的冷却技术研究

大型常压LNG储罐是LNG接收站中极其重要的单元设备,占有很高的投资比例,其正式启用时对调试工作的技术要求较高,而LNG储罐调试工作最关键和最危险的环节就是冷却。为此,详细介绍了国内LNG接收站常用16×104 m3 常压LNG储罐的冷却过程,分析了LNG储罐冷却前应具备的条件及注意事项,讨论了LNG储罐冷却过程中的压力控制、冷却介质（LNG）供应及流量控制、冷却过程的监控及冷却速率控制等调试技术,指出了冷却过程容易出现管线位移过大、法兰泄漏等问题,并给出了相应解决方法。研究成果对国内其他LNG项目具有借鉴意义。     

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钻井过程中，在井壁上形成的动态滤饼不仅是安全、快速钻进的重要因素，而且动态滤饼的质量与油气层受伤害的程度，测井解释的准确性、油气井的产能等都有重大的影响，因此，动态滤饼一直为国内外众多石油界专家、工程技术人员所重视，对它的研究也未曾中断。渗透率及厚度是动态滤饼的两个重要物性参数，影响因素很多，错综复杂。准确测定动态滤饼的渗透率和厚度是必要的，但也是不易的。以往的实验测定方法，需要人力、物力与时间，费时费事。笔者利用人工神经网络原理，建立了动态滤饼的渗透率及厚度预测的神经网络模型。从ＳＷ－Ⅱ型高温高压动态污染仪测得的实验数据，通过ＢＰ算法，对动态滤饼的渗透率及厚度作出参数预测，其精度在９０％以上，表明该模型的正确性。利用此模型作动态滤饼的参数预测具有省时、省事，在计算机上易于实现，操作简单、快捷的特点，在现场生产及室内研究中，此模型具有广泛的应用前景。     

科幻小说科学传播影响力提升的AMO 分析

随着互联网、手机的普及,搜索引擎以及基于搜索的互动式知识问答分享平台等自媒体应用,人们获取科学信息的能力与速度有了大幅提高。传统强调科学信息传播的“科学普及”,逐渐被强调从受众出发的“科学传播”所替代,后者更加注重传播过程的趣味性、情节性和传播效果的影响力。科幻小说在传播科学思想、科学观念、科学精神以及科学方法与知识方面,尤其符合自媒体时代的传播特征,显现出其他通俗科普读物难以匹及的科普功效。本文从传播学的角度出发,拟借助说服传播的精细加工可能性模型（ELM）,将其中的AMO （能力、动机、机会）三因素作为分析视角,对科幻小说科学传播影响力的提升提出了分众化、娱乐化、多媒体化的传播策略。