隧道围岩施工监测及位移动态模拟分析

为了研究不同支护结构参数和不同开挖方法对围岩位移的影响,以百勺洋隧道为研究对象,通过现场实测、回归分析和数值模拟的技术手段,以大型非线性有限元软件ADINA为研究工具,建立有限元模型。通过改变锚杆支护相关参数和开挖方法,进行大量模拟运算。运算结果表明,随着锚杆长度的增加,地表点下沉量不断减小,隧道的底鼓幅度也逐渐减小,边墙的收敛量也逐渐减小;随着锚杆间距的增加,顶端最大下沉点的竖直方向沉降值增大,边墙收敛值也增大;开挖方法不同时,随着开挖步数的减少,地表下沉值增加,隧道底鼓现象也越明显。开挖步数越多,洞周收敛值越小。     

深部岩体传热机理的研究现状与进展

基于国内外深部工程普遍面临的高温状况,探讨了深部高温的形成机制与影响因素。围绕岩体导热性质研究、水热耦合迁移问题和工程环境对传热的影响三个方面阐述了深部岩体传热机理的研究现状,目前的研究成果主要体现在建立了深部工程的热交换理论体系、矿山地热学的理论体系和地下工程制冷降温系统的热力学基础。在总结分析的基础上,确立了深部岩体流固耦合传热问题的研究思路：开展深部工程区域的的渗流场监测和开展岩体的流固耦合传热实验和建立岩体在应力-渗流-温度耦合条件下的传热模型,揭示深部岩体的传热机理。     

Microhabitat selection in the sand recluse spider (Sicarius thomisoides): the effect of rock size and temperature

In spiders, temperature is considered an important environmental variable for microhabitat selection. In this study, we evaluated the effect of temperature and rock size on the presence of the sand recluse spider Sicarius thomisoides and the degree of selectivity in different locations. This species is a large spider that lives under rocks in desert and semi-desert climates and is particularly active during the summer. In Chile, these spiders can be found at both coastal and inland locations under different thermal conditions, where usually the temperatures are lower near the coast. If large-scale climatic conditions are important for this species, they may be expected to select lower rock temperatures on the coast than at inland locations. In addition, we would expect that the spiders would choose larger rocks in inland compared to coast locations, which reduce the effect of high temperatures. We found that the probability of finding individuals of this species increased according to rock temperature and rock size in the field. Our results suggest that S. thomisoides prefers larger and warmer rocks to shelter under during the day, this selectivity being similar at both coastal and inland locations. Thus, this species tends to select rocks with the same thermal and structural conditions, independent of the climatic conditions.     

基于博弈论的开放环境下场景规约监控语义

在开放环境中,环境和系统本身行为的改变可能使得软件系统的实现不再满足原来规约,从而最终导致软件失效的发生.运行时监控是一种轻量级的形式化动态验证技术,已成为开放环境下检测软件失效的基本手段.针对基于场景的规约属性序列图,从博弈论的角度定义其多值监控语义:满足、无限可控、系统有限可控、系统紧急可控、环境有限可控、环境紧急可控和违例.通过多值监控语义的定义,监控器能够根据当前轨迹尽可能早地检测到系统失效或异常,并提供足够信息为失效的预防和恢复服务.实例研究表明了属性序列图多值监控语义的实用价值,并显示了其广泛的应用前景.     

急倾斜煤层巷道围岩变形破坏机理及支护研究

急倾斜煤层巷道大多采用单一的支护体系,变形破坏极为严重.为了找出适合急倾斜煤层巷道的支护体系,对急倾斜巷道围岩变形破坏特征进行了深入的分析.以赵家坝煤矿3964运输平巷作为研究对象,借助岩石点荷载试验、围岩松动圈测试和数值模拟软件,对该巷道围岩力学性质、围岩松动范围、应力分布、变形情况分别进行研究,得出急倾斜煤层巷道围岩变形破坏机理,提出了锚网索钢带+注浆的支护体系.工程实践表明,该支护体系大大增强了急倾斜煤层巷道的稳定性,为急倾斜煤层巷道支护提供了科学依据以及实践经验.     

超声热疗中媒质特性对声聚焦的影响

以凹球面自聚焦超声换能器为例,用瑞利积分进行数值模拟计算,研究声衰减、声速、温度等参数对声聚焦的影响,并对不同生物组织中声聚焦的特点进行了比较.研究表明,不同的媒质的特性参数聚焦表现出不同的特点.声衰减系数增大,则焦斑向声源靠近且焦斑缩短;声速越大,则焦距越小,但焦域最大声压值升高,焦斑的面积增大;温度变化不大时,对声聚焦的影响不明显.     

Forecasting for the LCD monitor market

The TFT‐LCD (thin‐film transistor–liquid crystal display) industry is one of the key global industries with products that have high clock speed. In this research, the LCD monitor market is considered for an empirical study on hierarchical forecasting (HF). The proposed HF methodology consists of five steps. First, the three hierarchical levels of the LCD monitor market are identified. Second, several exogenously driven factors that significantly affect the demand for LCD monitors are identified at each level of product hierarchy. Third, the three forecasting techniques—regression analysis, transfer function, and simultaneous equations model—are combined to forecast future demand at each hierarchical level. Fourth, various forecasting approaches and disaggregating proportion methods are adopted to obtain consistent demand forecasts at each hierarchical level. Finally, the forecast errors with different forecasting approaches are assessed in order to determine the best forecasting level and the best forecasting approach. The findings show that the best forecast results can be obtained by using the middle‐out forecasting approach. These results could guide LCD manufacturers and brand owners on ways to forecast future market demands. Copyright 2008 John Wiley & Sons, Ltd.     

基于PLC的船舶电站物理仿真综合实验装置的监控设计

开发研制了船舶电站物理仿真实验装置,对其主要的工作原理,尤其是并车控制器设计部分进行简要地介绍.通过对分布式控制结构、底层数据采集和高端管理软件等方面的研究,提出利用WinCC6.0组态软件和西门子S7系列PLC对自动化电站物理仿真实验装置进行监控系统设计.仿真结果表明,系统可以正确地实时监测和记录,监测效果很好.     

计算机监控的高压试验用大功率变频电源

针对当前电力系统中现场高压测试所面临的试验电源问题,提出了一种新型的高压试验用大功率变频电源的工作原理和设计方法,并在此基础上开发了其计算机监控系统,提高了该设备在使用过程中的安全性和自动化程度,现场试验和在实际中的应用证明该设备可靠性高、安全性好、实用性强。     

水中气泡群对水声信号传播的影响

从单个气泡的存在形式及其物理意义出发,针对水中声波对气泡的作用,进而形成的共振现象,阐述了气泡的“消声”特点．为今后靶场水声设备的建设以及相关试验,提出了重点关注的事宜．