Interval Charting Schemes for Joint Monitoring of Process Mean and Variance

Shewhart mean and variance schemes continue to enjoy great popularity among process engineers because they are easy to understand and are the most sensitive in detecting large process shifts. For some processes, for example the screen printing process in memory modules assembly, there is a possibility of the process mean and variance shifting at the same time due to special causes. Thus, instead of studying the joint behavior by looking at the mean and variance information on two separate charts, it is practical and usually more meaningful to look at the combined mean and variance information on an interval charting scheme. The interval scheme is found to have a similar run length performance to the Shewhart mean and variance schemes and only a single chart needs to be managed. A simple design procedure for the interval scheme that matches the corresponding Shewhart scheme is provided for easy implementation. Also, the interval and Shewhart schemes are compared based on real manufacturing data sets. Copyright © 2004 John Wiley & Sons, Ltd.     

节理倾向玫瑰花图在水利工程中的应用

采用节理倾向玫瑰花图和节理走向玫瑰花图分析某地区节理对坝基岩体稳定及渗漏的影响，比较说明了节理倾向玫瑰花图在水利工程应用中的相对直观、全面性。     

LW6-220开关绝缘拉杆脱落分析及对策

通过对一起绝缘拉杆脱落故障的主要原因分析，提出了针对LW6型开关的重点检修改造项目，对防止高压开关发生非全相故障，保证电网的安全稳定运行具有积极的意义。     

聊城2号机(600MW)高压转子叶片脱落的故障诊断

论述了聊城2号机组3000r/min稳定期间出现的机组异常振动,并根据振动特征正确诊断高压缸质量不平衡—高压第五级一叶片突然脱落的故障。     

智能路灯控制设计

本设计以TI公司的MSP430F2274单片机为核心组建了一个智能路灯控制系统。该系统由核心控制模块、键盘和显示模块、信号检测模块、LED恒流驱动电源模块、报警模块组成;实现了人机交互、开关灯的时间设定、LED灯随交通情况的自动调节、独立控制LED开和关的时间、报警功能以及LED灯的调光功能。     

Approximate trajectory tracking of input‐disturbed PVTOL aircraft with delayed attitude measurements

In this paper, we address the flight‐trajectory tracking problem of an input‐disturbed planar vertical take‐off and landing (PVTOL) aircraft with delayed attitude measurements. By applying the first‐order Padé approximation to deal with the time delay functions, the problem is reduced to the output tracking of a new non‐minimum‐phase system without delay. A tracking controller, consisting of a linear static‐state feedback term, a switching control term and a nonlinear auxiliary input term, is proposed for robust stabilization of the output‐tracking errors together with the internal dynamics. Numerical simulations are performed to show the main results. Copyright © 2009 John Wiley & Sons, Ltd.     

Analysis of through silicon via thermal stress induced device mobility variations

This paper studies the mobility variations of the devices placed in different crystal orientations induced by the through silicon via thermal stress. According to the elasticity theory, the mismatch of thermal expansion coefficients between copper and silicon substrate can induce the through silicon via thermal stress, which may cause carrier mobility variations due to the piezoresistive effect. In this paper, a compact analytical model of the through silicon via thermal stress is given based on the planar strain theory. Then the impacts of the through silicon via thermal stress on carrier mobility are presented by using Matlab with the channel direction along［100］ and［110］, respectively. And the Keep Off Zone is defined for considering the reliability of the device. Finally, we draw a conclusion that the［100］ crystal orientation and the［-110］ crystal orientation should be preferred as the NMOS device and the PMOS device, respectively.     

基于非线性压缩变换的某型航空发动机整机试车排故分析

基于非线性压缩变换对某型航空发动机整机试车振动信号进行了特征提取与故障诊断;非线性压缩变换由于其幅值无关性,能够增强微弱信号特征的表征能力,同时能够提高时频图的能量聚集性;对某型航空发动机进行地面整机试车试验,并通过数据采集装置获取各测点的振动信号,然后利用非线性压缩变换良好的微弱特征表征能力与时频聚集性,并结合其他信号分析方法,对采集到的振动信号进行分析;最终,结合航空发动机的结构与理论知识,实现了对其可能存在故障的排查与猜测,同时验证了非线性压缩变换在航空发动机实际试车振动信号分析中的有效性与实用性。     

Quantification of soil erosion and sediment yield for ungauged catchment using the RUSLE model: Case study for Lake Basaka catchment in Ethiopia

Soil erosion is a monumental land degradation problem in many parts of the world, threatening the well‐being of humans and ecosystems. The Lake Basaka catchment is heavily affected by serious land degradation problems related to land use–land cover changes (LULC), population dynamics and settlement, introduction of large‐scale irrigation schemes, etc. Accordingly, the objective of the present study was to quantify the magnitude of soil lost from the Lake Basaka catchment and the sediment subsequently delivered to the lake on the basis of the limited available dataset in a distributed manner using the RUSLE model in a GIS environment. The results indicated about 36 million m³ of soil were lost from the catchment between 1973 and 2007. Soil erosion and sedimentation in the lake catchment continue to increase from time to time, being attributed to the significant LULC occurring in the catchment. About 23 cm of the economically productive top soil in the catchment was lost during the study period (1960–2015), which translates into a significant degradation of the catchment (e.g. further reduction of infiltration capacity, thereby accelerating run‐off and erosion rates). Similarly, about a 1.3 m deep sediment layer was deposited in the lake during the same period. The computed sediment yield indicates about 14% of the lake incremental volume and depth in recent periods (post‐2000s) is attributable to sedimentation. Certain coincidental changes are also occurring in the catchment, including organic matter declines, soil nutrient depletion and soil depth decrement, which may lead to decreased production and productivity and associated ecosystem imbalances. The present study identified the potential areas that contribute significantly to erosion and sedimentation, thereby providing guidance regarding where land use/cover practices must be implemented to limit/reduce, if not avoid, the impacts of erosion and subsequent sedimentation in Lake Basaka.     

大型供水泵站泵阀启闭方式优化

由于离心泵的工作原理和特性,其泵组运行启闭方式一般为电机直接启动,水泵闭阀启动,关阀停泵,该方式对机组及配套水力机械设备产生较大振动。根据某大型泵站离心泵组运行实际情况,对该泵组启动方式进行优化,减轻了振动现象。