Localized relaxation theory of circuits and its applications in electro-thermal analyses

In the high-performance IC design with increasing design complexity,it is a very important design content to efficiently analyze IC parameters.Thus,the electro-thermal (ET) analyses including power/ground (P/G) analysis and thermal analysis are hot topics in today’s IC research.Since ET analysis equation has a sparse,positive definite and strictly diagonally dominant coefficient-matrix,we prove that the ET analysis has the advantage of locality.Owing to this advantage,localized relaxation method is formally proposed,which has the same accuracy as the global relaxation done with the constraint of the same truncation error limitation.Based on the localized relaxation theory,an efficient and practical localized successive over-relaxation algorithm (LSOR2) is introduced and applied to solve the following three ET analysis problems.(1) Single-node statistical voltage analysis for over-IR-drop nodes in P/G networks;(2) single-node statistical temperature analysis for hot spots in 3D thermal analysis;(3) fast single open-defect analysis for P/G networks.A large amount of experimental data demonstrates that compared with the global successive over-relaxation (SOR) algorithm,LSOR2 can speed up 1-2 orders of magnitudes with the same accuracy in ET analyses.     

基于几何解析的双雷达地面目标定位算法

传统的双雷达地面目标定位算法因测量数据本身固有的误差和量测噪声,使得基于非线性估计定位算法的定位精度不高。本文研究了一种新的双雷达地面目标定位算法,该算法将已知雷达探测数据以几何方式加以表示,通过几何解析对地面目标进行定位。此外,还详细分析了各种因素在不同情况下对定位精度的影响。所研究的算法具有计算量小、远距离定位精度高等优点。最后,通过仿真验证了该算法能够提高远距离定位的定位精度。     

卫星运行三维场景及星下点轨迹可视化研究

应用可视化技术构造卫星运行的虚拟场景,实时显示卫星运行状态及星下点轨迹,可为卫星轨道设计、卫星运行状态监控及卫星应用提供直观的分析和指导。通过对卫星轨道计算方法、几何建模、虚拟场景装配及虚拟场景驱动方法研究,本文开发了卫星运行三维场景及星下点轨迹可视化软件。本文详细给出了地球模型、卫星模型的建模及由此模型组装卫星运行场景的方法,卫星轨道计算及星下点轨迹可视化方法。该软件可实时模拟卫星在太空中的运行场景,给出卫星的即时经纬度坐标及星下点位置坐标。该软件已在实践中得到应用。     

水工混凝土构件裂缝检测方法及应用

水利工程在长期运行过程中,其混凝土构件会出现磨蚀、裂缝等损伤,如这类问题不能够及时得到处理,将会严重影响水利工程的安全运行。本次研究主要针对水工混凝土构件中的裂缝检测方法进行研究,提出从“定性”到“定量”的一体化检测思路,具体实施过程分为四部分,即“普探—详查—判定—验证”,其中,普探阶段采用探地雷达法,确定裂缝的总体分布;详查阶段采用超声横波反射三维成像的方法,确定裂缝的纵深向分布;判定阶段分别采用裂缝测宽法和表面声波法,用来确定裂缝的表面宽度和贯穿深度;验证采用钻孔电视,确定探测结果的正确性和准确性。上述技术路线突破了单一方法的限制,可有效地运用于水工混凝土构件裂缝检测,经实践证实,具有良好的检测效果。     

电力配电网单相接地故障选线技术的发展

作为供电系统中的重要部分,电力配电网的重要性毋庸置疑。从实际情况来看单相接地故障是配电网建设与使用过程中经常出现的问题,要求专业人员提高对选线环节的重视,选择应用多种科学的选线方法以从根本上降低单相接地故障的发生风险。本文阐述了常见的几种故障选线方法,并就每一种线型的特性进行了分析。     

新型防雷及抗干扰方法在电铲控制系统的应用

电铲是采区主要采掘设备,其弱电控制系统是电铲正常可靠运行的关键。由于雷击或电磁干扰造成弱电控制系统装置的损坏或工作异常等故障,已成为影响电铲安全正常运行的重要因素。针对现有电铲控制系统防雷抗干扰现状、存在的问题及影响,研究了一种新型防雷抗干扰方法,并分析了其在电铲弱电控制系统中的应用和实施效果。实际运行表明,新型防雷抗干扰方法能够有效提高电铲弱电控制系统防雷及抗干扰能力,对电铲及其他弱电控制系统防雷抗干扰的研究和应用具有积极的现实意义,且有着很好的推广价值。     

湿陷性黄土地区几种地基处理方法的比较

通过一工程实例,介绍了在湿陷性黄土地区几种地基处理方法的应用,并从技术、经济、施工进度等方面进行了分析比较,可供土建设计人员借鉴、参考。     

高地温条件下深埋隧洞围岩温度—应力分析及施工对策

以位于西昆仑山区的齐热哈塔尔水电站引水发电隧洞高地温洞段为例,初步分析了工程区隧洞高地温洞段大地热流背景及其形成机理,针对隧洞围岩的高地温分布特征,建立典型高地温洞段地质模型,利用有限元软件模拟隧洞施工贯通通水后的围岩岩体温度场,并由此来推断热应力对于围岩稳定性的影响。结果表明,围岩温度90℃以上、空气温度50℃以上的高地温洞段,内外温差大于10℃(里低外高),若采用无衬砌和一次支护方案对高地温洞段围岩进行支护,该洞段内大部分区域的最大主拉应力将超过C25混凝土的抗拉强度,易产生整体拉裂破坏;若采用钢筋混凝土衬砌结构方案,则可以通过增加衬砌结构的配筋量来降低其最大主应力值,此时隧洞围岩及衬砌结构均未出现整体拉裂破坏。研究成果能够为保证该高地温隧洞的安全运行提供可靠的设计依据。     

流动注射分析法对复合肥中五氧化二磷的分析

在复合肥的生产过程中，用流动注射分析测定磷矿，磷石膏，磷酸中的五氧化二磷，该方法制样简单，分析速度快，结果准确。     

Longitudinal and temporal water temperature patterns in the Yangtze River and its influence on spawning of the Chinese sturgeon (Acipenser sinensis Gray 1835)

In this study, water temperature longitudinal and temporal patterns were investigated in four locations of the Yangtze River to identify their influence on spawning of the Chinese sturgeon (Acipenser sinensis Gray 1835). The results showed that, historically (1960–1980), the four locations, Pingshan (PS, 2,687 river kilometres [rkm]), Yichang (YC, 1,640 rkm), Chenglingji (CLJ, 1,265 rkm), and Hukou (HK, 805 rkm), all had similar average annual water temperatures (around 18.0 °C) but very different amplitudes: The upper two locations, PS (11.4–23.2 °C) and YC (9.1–25.9 °C), were relatively stable and had smaller amplitude than the lower two ones, CLJ (6.0–30.0 °C) and HK (5.9–30.8 °C). On the basis of the physiological effects for Chinese sturgeon, we defined three water temperature ranges: stressing (>23 °C), holding (23–20 °C), and spawning (20–16 °C). We found that the upper two locations with successful spawning of the Chinese sturgeon (PS and YC) had short or no stressing period but long holding and spawning periods. Currently (2013–2016), the impoundment of the Three Gorges Reservoir increases the time for water temperature decreasing to 20 °C at the current spawning ground (YC) in autumn, which increases the stressing and holding periods, and has significant negative impact on the spawning of Chinese sturgeon. Nonetheless, considering the very high stressing temperature and the short duration of the holding and spawning periods at CLJ and HK, we propose that YC is still the most suitable spawning location for the Chinese sturgeon.