Effect of increased linings on micro-pressure waves in a high-speed railway tunnel

A micro-pressure wave (MPW) is generated when a train enters a tunnel at high speed, which causes a strong impact on the environment around the tunnel. The increased lining used to repair damage in high-speed railway tunnels changes cross-sections and has a strong influence on the MPW at the tunnel exit. In this paper, the methods of full-scale measurement, numerical simulation and moving-model experiments are used to study the MPW generated in a tunnel whose lining is increased. The rules governing the effect of increased linings on MPWs are obtained, which can be used as a reference for the Tunnel Damage Regulation Project in China.     

标准CMOS工艺在高速模拟电路和数模混合电路中的应用展望

从速度、集成度、功耗和成本等几个方面深入的分析了利用标准CMOS工艺来设计开发高速模拟器件和混合处理芯片的现状及发展潜力。     

电子类EDA教学中引入MPW计划的研究与实践

EDA技术的快速发展，给我国高校电子技术教学带来严峻挑战。如何使高校培养的EDA人才符合市场需求，是现代EDA教学改革的目标。论文首先分析了现代EDA教学现状，介绍了MPW的基本概念及国内外MPW计划的实施情况，然后提出在本科电子类EDA教学中结合科研项目，引入MPW计划的必要性和可行性，并以多年来我校工程实践和毕业设计实践说明MPW计划在现代电子设计教学和人才培养中的作用。     

Wave formation mechanism in magnetic pulse welding

Wavy interface morphology is observed in Magnetic Pulse Welding (MPW) similarly to that of the Explosion Welding process (EXW). It is recognized that interfacial waves are formed in a periodic manner and have well defined wavelength and amplitude. The phenomenon of wave formation in EXW has been subjected to extensive investigations in which empirical and numerical models have been published. In the present study, a wave formation mechanism for MPW is presented. This wave-creation mechanism was studied by evaluating the influence of sample geometry on wave morphology using stereoscopic optical microscopy. It was found that interfacial waves are formed in a Kelvin–Helmholtz instability mechanism. Reflected shock waves interact with the welding collision point at the weld interface, where interferences are the source for the wave's initiation. The collision energy, impact angle, and the geometry of the joint, were found to have the most significant influence on the waves' characteristics. An empirical relationship between interfacial wavelength and the free moving distance of the shock waves in the welded tubular parts was found.     

考虑缺陷率模型的多项目晶圆布图规划算法

针对随机缺陷会降低多项目晶圆实际产出的问题,提出一种新的多项目晶圆布图规划算法。通过在布图规划中引入缺陷率模型的方法,增加芯片产量的裕量,降低因随机缺陷造成的产量损失。同时优化模拟退火流程,使得在布图尺寸约束条件下,布图规划过程能够跳出局部最优解陷阱。对工业实例进行布图规划的结果表明,该算法能够接受不满足布图尺寸约束条件的中间结果,从而遍历解空间,得到全局最优的布图,并且相对已有算法,使用相同数量晶圆进行切割时,算法的布图结果增加了137%的芯片产量的总裕量,同时,降低了25%的工作芯片所需要生产的晶圆数量。     

利用光刻机挡板优化MPW光罩布局

伴随着国内市场竞争的日趋激烈,常规的MPW(多项目晶圆)布局也不能满足客户的要求,同时也不能最大限度地降低设计公司的研发成本,也不利于国内foundry厂市场的开拓.鉴于此,文章着重提出了利用光刻机挡板把光罩进行区域划分,在不增加流片和满足客户要求的前提下,使光罩得到最大限度的利用,降低了客户的流片费用.通过在15cm...     

电磁轴承功率放大器参数设计

由于功率放大器处于电磁轴承系统的执行环节,其动态性能将直接影响系统的性能。为了提高电磁轴承系统的性能,针对电流响应速度、力的响应速度、同频允许的最大振幅和不平衡量控制等指标,以采用最小脉宽开关功率放大器的电磁轴承系统为例,从系统的频响角度出发,分析了满足实际工况下功率放大器参数设计要求。从而在保证系统运行性的同时,通过合理设计功率放大器的主要个数,节省设备制造成本。在经过理论分析和仿真试验之后,给出一些设计的实例,从而对实际电磁轴承功率放大器的设计提供了指导依据。     

Application of high velocity impact welding at varied different length scales

Three complementary impact welding technologies are described in this paper. They are explosive welding, magnetic pulse welding, and laser impact welding, which have been used to provide metallurgical bonds between both similar and dissimilar metal pairs. They share the physical principle that general impact-driven welding can be carried out by oblique impact but are used at different length scales from meters to sub-millimeter. The different length scales require different kinds of systems to drive the process, and the scales themselves can give different weld morphologies. Metallographic analysis on cross-sections shows a wavy interface morphology which is likely the result of an instability associated with jetting, which scours the surfaces clean during impact. The normalized period and amplitude of the undulations increase with increasing impact energy density. Microhardness testing results show the impact welded interface has a much greater hardness than the base metals. This can lead to weldments that have strengths equal to or greater than that of the weakest base material.     

通过MPW降低IC设计创新门槛

多项目晶圆(Multi-Project Wafer,MPW)是降低IC设计风险的重要手段之一。以搭建交流IC设计和流片经验、了解最新工艺发展,共同推动MPW服务平台建设为目的,上海集成电路技术与产业     

电磁成形技术在汽车制造中的应用

介绍了电磁成形基本原理,阐述了电磁复合冲压成形与电磁焊接在汽车制造领域中的应用以及其成形件的性能研究现状,探讨了电磁成形技术的发展趋势:将在铝合金汽车制造方面发挥巨大的作用。