浅谈压延铜箔光面色差的成因

针对压延铜箔在表面处理过程中光面易出现色差的问题,从设备、工艺、人员操作等方面进行成因探讨,并给出了应对措施。     

帮坡角变化对露天矿采剥量以及经济效益的影响

露天矿最终帮坡角是影响露天矿安全生产的主要因素之一,也对露天经济效益产生重要影响,特别是对大型深凹露天矿的影响尤为突出。在保障露天矿安全生产条件下,本文通过优化矿区不同帮坡角条件下的最终境界,研究帮坡角变化对矿山岩石剥离量、矿石采出量以及经济效益的影响。结果表明,随着帮坡角的增加,最终境界内的岩石剥离量、矿石采出量可能增多也可能减少,但经济效益呈现增加趋势。     

Unsteady conjugate mass transfer of a 2D deformable droplet in a modest extensional flow in across-slot

This work aims to investigate the unsteady conjugate interphase mass transfer between a stationary deformed drop and the modest extensional flow in a cross-intersected 2D channel. It is very difficult to accurately quantify the transient mass transfer rate of solute in such a geometry. Therefore, we established a mathematical model on the basic of the Stokes equation and solved it by the boundary element method, which could deal precisely with a two-phase flow system with a deformable interface; meanwhile, the convection-diffusion equation was solved by the finite difference method to calculate the unsteady conjugate interphase mass transfer. The simulation results showed that the mass transfer rate, analyzed and characterized in terms of mean concentration variation and Sherwood number Sh, was affected by capillary number Ca, Peclet number Pe, viscosity ratio λ , interior-to-exterior diffusivity ratio K, distribution coefficient m, and wall effect factor W.     

茅台酒厂26层剪力墙结构大楼爆破拆除

根据茅台酒厂钟楼的结构特性、周围环境特点及爆破要求,分析该栋26层高楼的爆破拆除控制要点,采用了单向三折叠的爆破方案。通过爆破方法预先拆除切口内部分剪力墙,有效地降低爆破总药量;通过切口间开设铰链,使大楼在空中充分解体,减小了塌落体的触地块度,从而降低了触地冲击;采用胶皮网覆盖和敷设减振带等防护措施,有效地控制了爆破飞石及触地振动。结合高速摄影对钟楼倒塌后坐造成排污管及排污沟破坏的原因进行了分析,可为类似工程提供参考。     

高纯半绝缘SiC电阻率影响因素

采用物理气相传输(PVT)法进行高纯半绝缘SiC晶体生长,利用高温真空解吸附以及在系统中通入HCl和H2的方法,有效降低了系统中N、B和Al等杂质的背景浓度。使用二次离子质谱(SIMS)对晶体中杂质浓度测试,N、B和Al浓度分别小于1×1016、1×1015和2×1014 cm-3。对加工得到的晶片进行测试,全片的电阻率均在1×1010Ω·cm以上,微管密度小于0.02 cm-2,(004)衍射面的X射线摇摆曲线半高宽为34″。结果表明,该方法可以有效降低SiC晶体中N、B和Al等杂质浓度,提升SiC晶片的电阻率。使用该方法成功制备了4英寸(1英寸=2.54 cm)高纯半绝缘4H-SiC晶体。     

基于未确知集对联系数法的溃坝社会影响评价

针对溃坝社会影响因素的不确定性和复杂性易造成评价过程信息缺失的问题,采用未确知测度理论和层次分析法,将其不确定信息转换为具有相对确知信息的综合测度向量,结合集对分析可有效处理研究系统的确定性与不确定性关系的特点,引入五元集对联系数,建立了基于未知集对联系数法的溃坝社会影响评价模型,以未确知集对联系数所属区间的等级作为溃坝社会影响严重程度等级判定的依据,并通过工程实例验证了所建溃坝社会影响评价模型的合理性和有效性,为溃坝社会影响评价提供了一种新的方法和思路。     

Study of the behavior of mechanically stabilized earth (MSE) walls subjected to differential settlements

The limit equilibrium (LE) analysis has been used to design MSE walls. Presumably, the deflection of MSE walls can be limited to an acceptable range by ensuring sufficient factors of safety (FOSs) for both external and internal stabilities. However, unexpected ground movements, such as movements induced by excavations, volume changes of expansive soils, collapse of sinkholes, and consolidations of underlying soils, can induce excessive differential settlements that may influence both the stability and the serviceability of MSE walls. In this study, a numerical model, which was calibrated by triaxial tests and further by a specially-designed MSE wall tests, investigated the behavior of an MSE wall as well as the influence of various factors on the performance of the MSE wall when the wall facing settled relatively to the reinforced zone. The numerical results showed that the differential settlement would cause substantial vertical and horizontal movements for the MSE wall, as well as an increase in lateral earth pressure and geosynthetic reinforcement strain. The maximum horizontal movement and increase of the lateral earth pressure occurred at about 1.0 m above the toe. The differential settlement resulted in a critical plane that coincided with the plane of 45°+?/2. The maximum increase of the strain for each geogrid layer occurred in that plane, and the bottom layer had the greatest strain increase among all layers of reinforcement. The study further indicated that the surcharge, backfill friction angle, tensile stiffness of geogrid, reinforcement length and MSE wall height had noticeable influences on horizontal and vertical movements, and strain in geosynthetics. According to the results, the MSE wall that had a higher factor of safety would have less movements and geosynthetic strain increase. In contrast, only the friction angle, tensile stiffness and MSE wall height showed some degree of influence on the lateral earth pressure due to differential settlements.