矿用钻孔深度测量仪的设计

设计了一种以STM32F103微控制器为控制核心,基于24位高精度模数转换器的钻孔深度测量仪器。利用弹性波回波测距原理,通过测量出钻孔中钻杆的长度,实现钻孔深度的快速、无损、准确的测量,主要用于井下瓦斯抽放钻孔、探放水钻孔等煤矿通防工作的施工验收。仪器小巧轻便,操作简单,单人即可完成测量工作,节约下井的人力物力,提高生产效率,最长测量长度可达250米,误差不超过1米。     

Enhancing urban infrastructure investment planning practices for a changing climate.

Climate change raises many concerns for urban water management because of the effects on all aspects of the hydrological cycle. Urban water infrastructure has traditionally been designed using historical observations and assuming stationary climatic conditions. The capability of this infrastructure, whether for storm-water drainage, or water supply, may be over- or under-designed for future climatic conditions. In particular, changes in the frequency and intensity of extreme rainfall events will have the most acute effect on storm-water drainage systems. Therefore, it is necessary to take future climatic conditions into consideration in engineering designs in order to enhance water infrastructure investment planning practices in a long time horizon. This paper provides the initial results of a study that is examining ways to enhance urban infrastructure investment planning practices against changes in hydrologic regimes for a changing climate. Design storms and intensity-duration-frequency curves that are used in the engineering design of storm-water drainage systems are developed under future climatic conditions by empirically adjusting the general circulation model output, and using the Gumbel distribution and the Chicago method. Simulations are then performed on an existing storm-water drainage system from NE Calgary to investigate the resiliency of the system under climate change.     

Exposed Die-Top Encapsulation Molding for an Improved High- Performance Flip Chip BGA Package

The recent advancement in high- performance semiconductor packages has been driven by the need for higher pin count and superior heat dissipation. A one-piece cavity lid flip chip ball grid array (BGA) package with high pin count and targeted reliability has emerged as a popular choice. The flip chip technology can accommodate an I/O count of more than five hundreds500, and the die junction temperature can be reduced to a minimum level by a metal heat spreader attachment. None the less, greater expectations on these high-performance packages arose such as better substrate real estate utilization for multiple chips, ease in handling for thinner core substrates, and improved board- level solder joint reliability. A new design of the flip chip BGA package has been looked into for meeting such requirements. By encapsulating the flip chip with molding compound leaving the die top exposed, a planar top surface can be formed. A, and a flat lid can then be mounted on the planar mold/die top surface. In this manner the direct interaction of the metal lid with the substrate can be removed. The new package is thus less rigid under thermal loading and solder joint reliability enhancement is expected. This paper discusses the process development of the new package and its advantages for improved solder joint fatigue life, and being a multichip package and thin core substrate options. Finite-element simulations have been employed for the study of its structural integrity, thermal, and electrical performances. Detailed package and board-level reliability test results will also be reported     

连续油管技术与装备发展综述

自世界上第一台连续油管作业机问世至今,连续油管作业技术与装备已经过了40多年的发展历程,以其占地面积小、作业成本低、搬迁安装方便、保护油层、增加油井产量和使用范围广等诸多不可比拟的优势,得到迅速发展,并广泛应用于钻井、完井、试油、采油、修井和集输等各个作业领域。实践表明,连续油管作业技术与装备是一项具有巨大潜力和生命力的实用性技术。目前,该项技术的应用日趋活跃,备受关注。在总结连续油管作业技术与装备的发展现状和展示其发展趋势的基础上,客观地分析了国内连续油管技术与装备的应用与研究现状,提出相应的发展对策。