Spatial and Temporal Evolution of the Static Water Level of the Cuauhtemoc Aquifer during the Years 1973, 1991 and 2000: A Geographical Approach

In hydrogeology it is of great interest to examine the temporal and spatial evolution of aquifers. There are different ways of modeling an aquifer: physical models, models based on analog and mathematical techniques. Usually, mathematical techniques involve complex operations difficult to understand for some people, such as differential or partial equations. In contrast, our method requires only a basic knowledge of geometry and trigonometry. Moreover, it is only necessary to know the static level of the aquifer at three different dates. Of course, the results may be limited compared to those that use advanced mathematical methods;however, our method provides a first approximation to determine the behavior of the aquifer through time. Overall, our results allowed us to follow the evolution of the aquifer in detail of various areas of increased extraction and in which removal has been increasing, but also of areas with a considerable recharge during the study period.

基于静力水准的采空区地表变形监测及误差分析

目前,采空区上方的地表沉降变形监测主要采用人工水准仪测量,该方法效率低、成本高、周期长,且无法实现自动化实时监测。为解决上述问题,引入静力水准自动化监测技术,在分析静力水准自动化监测工作原理及监测系统构成的基础上,对其可靠性、误差来源及消除方法进行了深入探讨,最后结合条带采空区上方地表监测实例从监测方案、测点布置、数据分析等多个角度进行了系统研究。研究结果表明:该技术能够满足条带采空区上方地表沉降变形自动化监测的要求,可为相关监测工作提供技术支撑。

Graph Modeling for Static Timing Analysis at Transistor Level in Nano-Scale CMOS Circuits

The development and the revolution of nanotechnology require more and effective methods to accurately estimating the timing analysis for any CMOS transistor level circuit. Many researches attempted to resolve the timing analysis, but the best method found till the moment is the Static Timing Analysis (STA). It is considered the best solution because of its accuracy and fast run time. Transistor level models are mandatory required for the best estimating methods, since these take into consideration all analysis scenarios to overcome problems of multiple-input switching, false paths and high stacks that are found in classic CMOS gates. In this paper, transistor level graph model is proposed to describe the behavior of CMOS circuits under predictive Nanotechnology SPICE parameters. This model represents the transistor in the CMOS circuit as nodes in the graph regardless of its positions in the gates to accurately estimating the timing analysis rather than inaccurate estimating which caused by the false paths at the gate level. Accurate static timing analysis is estimated using the model proposed in this paper. Building on the proposed model and the graph theory concepts, new algorithms are proposed and simulated to compute transistor timing analysis using RC model. Simulation results show the validity of the proposed graph model and its algorithms by using predictive Nano-Technology SPICE parameters for the tested technology. An important and effective extension has been achieved in this paper for a one that was published in international conference.

Kalman滤波在自动化监测数据噪声处理上的应用研究

对Kalman滤波在静力水准和固定式测斜仪原始数据降噪处理中的应用进行研究。结果表明,在缓慢变形条件下,Kalman滤波可以有效过滤原始数据中的噪声,提供试验结果,还原监测对象真实变形情况。但在突发变形情况下,Kal-man滤波反应滞后。因此,实际应用中应综合使用滤波前和滤波后的数据,以更准确地研判变形趋势和规律,为自动监测数据的噪声处理提供了新的思路和方法。通过Kalman滤波的应用,可以进一步提高监测数据的准确性和可靠性,为工程安全监测和地质灾害预警等领域提供支持。

基于力图解原型的结构形态参数化生成

图解静力学由彼此交互的力图解和形图解组成,通过力图解生成形图解对方案阶段的结构形态推敲有十分积极的作用。本文首先根据认知心理学的理论,分析得出力图解原型应具备适宜的抽象水平,即中等抽象水平;其次,从结构内力方向、支座数量、构件姿态、荷载分布状态与荷载分解方式构建了二维力图解原型谱系;最后,确定参数数量、梳理参数间关系、编写程序生成多个结构形态。本文的研究目的旨在提升力图解操作的交互水平,使设计师在构思方案时更容易操作。

柳州站悬臂结构施工分析及监测

以柳州火车站的高架层悬臂结构为工程背景,通过有限元法分析了施工阶段临时支撑回顶与否,临时支撑和临时支架拆除与否等不同工况的内力、变形、裂缝等结果,确定了悬臂板上部设置临时支架,下部设置临时支撑进行回顶,后期拆除临时支撑和临时支架的施工方案。同时为了保证施工的顺利进行,利用静力水准仪进行了挠度的监测,通过监测发现变形符合规范要求,保证了施工安全。

浅析动车组转向架静压载试验调平影响因素

介绍了我国高速动车组转向架技术发展的历程,根据CRH1型动车组转向架静压载试验的具体要求,非常详细地分析了构架、轮径、弹簧组3个关键因素对转向架静压载试验的影响,并针对这些影响因素提出了具体调平措施。对于进一步提高静压载试验一次合格率具有较强的实际意义。

静力水准自动化监测在运营地铁隧道的应用研究

为了实时获得地铁运营时隧道的变化情况,确保地铁运营的安全性,以静力水准仪自动化监测在某城市运营地铁隧道下穿洛河段的应用为例,将人工监测数据和静力水准自动化监测数据在不同季节进行对比分析,验证静力水准自动化监测的可靠性。研究结果显示,静力自动化水准仪具有高精度、实时性和可靠性,在地铁隧道监测中具有较高的应用价值。

临近基坑建筑物沉降自动化监测方法研究

为实时掌握基坑工程施工期间临近建筑物的安全状态,信息化指导施工,文中以某市政基坑工程施工为例,将静力水准仪应用于基坑周边临近建筑物沉降的自动化监测,对自动化监测精度和建筑物沉降变形规律进行分析,并将自动化监测和人工监测数据进行对比。结果表明静力水准仪自动化监测观测精度高,具有较好的系统稳定性,可用于建筑物变形的实时监测,对信息化施工和保证建筑物安全具有重要意义。

等级保护测评过程中常见的静态密码风险及防护建议

随着信息科学的发展,身份验证技术也随之持续更新,但静态密钥仍然是信息系统中最常见的身份验证手段。尤其是伴随着信息系统构造模式的转变,信息系统相关的操作系统、网络设施、保护装置等领域的静态密钥面临着新的挑战。本文梳理了在等级保护评价流程中经常遇到的静态密码危机,并为每种危机制定了适当的预防方案。

基于实车试验的大跨度桥梁轨道静态长波高低不平顺验收标准验证

由于温度、施工偏差、二期恒载等因素影响,高速铁路大跨度桥梁成桥线形与设计线形存在较大差异,且矢距差法不适用于大跨度桥梁和地基大面积沉降等区域的轨道线形验收。针对速度为250 km/h的高速铁路有砟轨道大跨度桥梁,基于轨道高低不平顺不同弦测值与车体垂向振动加速度之间的相关性,提出高低不平顺60 m弦测值与车体垂向振动加速度之间的关联关系,进而给出桥上轨道静态高低长波不平顺60 m中点弦测值10 mm的验收限值建议,最后在某主跨为672 m的高速铁路斜拉桥上预设“四峰三谷”形式的轨道高低不平顺并进行实车验证,证明此限值建议的合理性。结果表明:对于速度为250 km/h的高速铁路,车体垂向振动加速度与不平顺60 m弦测值之间呈线性关系;大跨度桥梁温度变形显著,整体表现为桥面高程与温度成反相关关系,但桥梁温度变形主要表现为长波不平顺;预设的60 m余弦波形式的轨道高低不平顺主要影响行车舒适性,对安全性影响较小,且列车速度在275 km/h及以下时,产生的车体垂向振动加速度最大值为0.98 m/s2,舒适性指标最大为2.47,评价为“优秀”,接近优秀/良好分界线。

浅析油品蒸发损耗及发展趋势

油品蒸发损耗不仅影响环境质量,还影响油品质量。除了该问题之外,蒸发损耗将促进汽油氧化,辛烷值减小,长时间运行对汽车发动机造成不利影响。此外,油品蒸发损耗还有一定的安全隐患,易造成局部火灾,并对人类和动植物也有毒害性。目前,国内外正结合油品蒸发损耗的相关因素,发掘降耗措施,比如对输送和储油设备的结构进行设计和改进,尽可能加大对烃蒸气的回收力度,并采取合适的方法来抑制油品蒸发损耗。

Static loading and vertical displacement at southern Siberia

Seismic method is usually used for elastic parametric estimation. This is why this method presents dynamic parameters of Earth. Frequency seismic range changes greatly from geodynamic modelling time. Now we have opportunity to use geodesy result for some years for elastic parameters estimation. Static solution from elastic theory may be used for the interpretation of long term results. It presents static elastic parameter. The inverse problem for different types of vertical surface loading on one year period is calculated. Two cases of loading with maximal and minimal area are presented. Results are determined by space geodesy and leveling methods. Current relation between atmospheric pressure and vertical displacements was estimated at the center of Siberian Anti Cyclone with size varied from 2000 km to 3000 kin. Pressure-displacement coefficients （PDC） can be achieved by three years obser- vation （0.997 mm/mbar for NVSK GPS station）. It is used for elastic module study of geology medium with maximum thickness up to 600 km. In the context of elastic model, the modulus of rigidity is estimated to be 113 GPa. Vast expanse of anti-cyclone may relate with rheology of crust and upper mantle. Smaller size of surface loading - local loading is seasonal variation of water reservoir. Annual vertical changes were obtained by leveling near the dam of the reservoir. PDC ratio was 1.15 mm/bar for these places. In elastic theory, the Young modulus E = 80 GPa （Poisson ratio = 0.25, the modulus of rigidity - 32 GPa） was calculated by sixteen years of leveling measurements. This result can effectively be represented for upper crust. Our results were checked by solution for coseismic displacement of Chyia- Altai earthquake （Sep. 27, 2003, M = 7.3）. Coseismic results calculated by static modules agree with experimental coseismic GPS data at 10% level.

A study on the seismic behavior of a retrofitted building based on nonlinear static and dynamic analyses

This study describes the seismic performance of an existing five storey reinforced concrete building which represents the typical properties of low-rise non-ductile buildings in Turkey. The effectiveness of shear walls and the steel bracings in retrofitting the building was examined through nonlinear static and dynamic analyses. By using the nonlinear static analysis, retrofitted buildings seismic performances under lateral seismic load were compared with each other. Moreover, the performance points and response levels of the existing and retrofitting cases were determined by way of the capacity-spectrum method described in ATC-40 (1996). For the nonlinear dynamic analysis the records were selected to represent wide ranges of duration and frequency content. Considering the change in the stiffness and the energy dissipation capacities, the performance of the existing and retrofitted buildings were evaluated in terms of story drifts and damage states. It was found that each earthquake record exhibited its own peculiarities, dictated by frequency content, duration, sequence of peaks and their amplitude. The seismic performance of retrofitted buildings resulted in lower displacements and higher energy dissipation capacity depending mainly on the properties of the ground motions and the retrofitting strategies. Moreover, severe structural damage (irreparable or collapse) was observed for the existing building. However, buildings with retrofit alternatives exhibited lower damage levels changing from no damage to irreparable damage states.

一种快速准确的大功率IGBT建模方法

高压大功率绝缘栅双极晶体管(insulated gate bipolar transistor,IGBT)的准确建模对IGBT应用中的损耗计算、机理分析、骚扰特性预测有重要意义。基区载流子分布计算是IGBT建模的核心内容,对于计及不同注入条件下大功率IGBT载流子分布计算,现有模型存在计算量大或精度低等缺点。文中首先研究大功率IGBT工作过程中基区载流子的分布特性,然后,以准静态和非准静态条件下基区载流子分布的差异性为突破口提出一种快速、准确、适用于大功率IGBT的建模方法。依据器件内基区耗尽层的边界是处于栅极区域附近还是越过栅极区域,该方法将IGBT工作状态分为两部分,并分别基于准静态假设和非准静态假设对两部分建模。由此可在不失精度的情况下避免载流子二维分布计算,有效地减小在计及不同注入条件下的计算量。最后,通过与现有方法和试验对比,验证所提方法在精度和计算速度方面的优势。

Numerical Simulation of Level Magnetic Field

According to Maxwell electromagnetic field theory and magnetic vector potential integral equation,a mathematical model of LMF(Level Magnetic Field)for EMBR(Electromagnetic brake)was proposed,and the reliable software for LMF calculation was developed.The distribution of magnetic flux density given by numerical simulation shows that the magnetic flux density is greater in the magnet and magnetic leakage is observed in the gap.The magnetic flux density is uniform in horizontal plane and a peak is observed in vertical plane.Furthermore,the effects of electromagnetic and structural parameters on magnetic flux density were discussed.The relationship between magnetic flux,electromagnetic parameters and structural parameters is obtained by dimensional analysis,simulation experiment and least square method.

基于多指标分析的大跨度超高超重钢连廊整体提升施工控制技术

针对大跨度超高超重钢连廊在整体提升过程中提升时间长、结构偏心、遭遇台风雨季以及不同步位移积累等一系列难点,采用包括钢索索力、竖向位移、应力、风速、倾角等多指标分析控制的方法,并首次提出采用计算扭转变形的姿态控制设置预警值,不仅使钢结构连廊整体提升提前顺利完成,而且监控结果与理论计算结果接近,取得良好的效果,充分说明该控制方法的科学性和可行性,优化了提升施工过程,同时为其他整体提升项目提供了重要参考。

静力水准仪测试大型钢构件不同步提升位移的应用研究

针对大型钢结构整体提升过程中产生的不同步位移,通过有限元软件进行敏感性分析后,首次提出采用计算扭转变形的姿态控制设置预警值,并在每个连廊吊点上安装静力水准仪,用静力水准仪精准控制每个吊点的不同步位移,最终钢结构连廊整体提升提前顺利完成。该方法相比传统的通过光学仪器校核调整不同步位移的方法更加科学,不仅提高了结构提升效率,减少了大量滞空时间,而且适用于夜间施工,优化了提升施工过程。

CFRP−泡沫铝夹芯结构控制臂优化设计

为满足控制臂的轻量化设计需求,提出了一种采用碳纤维复合材料(CFRP)−泡沫铝夹芯结构的汽车悬架控制臂,并对CFRP面板进行结构优化设计.通过泡沫铝准静态压缩试验验证了泡沫铝六面体胞孔模型的准确性,利用CFRP力学性能试验获得了碳纤维复合材料的性能参数,设计一种由CFRP−泡沫铝夹芯结构本体和铝合金连接件组成的悬架控制臂,控制臂本体与连接件之间采用胶−螺混合连接.在此基础上,建立CFRP−泡沫铝夹芯结构控制臂有限元模型,利用多层次优化方法对CFRP面板进行铺层优化.结果表明,相较于钢制控制臂,优化后夹芯结构控制臂的质量减少了26%,同时强度、刚度和模态性能都有所改善.

高精度小量程静力水准仪的设计与应用

设计了一种高精度小量程静力水准仪,详细阐述了其测量原理和机械结构。分析了静力水准仪在沉降监测应用中的系统精度,并根据系统精度设计确定了仪器出厂的最大残余误差。为保证仪器的测量精度,进行了仪器关键器件的选型。经试验验证,该静力水准仪具有测量精度高、重复性好、迟滞误差小、分辨率高和环境适应性强等特点,满足设计要求。将该静力水准仪应用于某大科学装置的沉降位移监测中,通过现场抬升实验和应用数据分析,表明该静力水准仪测量精度满足项目设计精度,实现了对大科学装置的沉降变化的实时精确监测,为该装置的稳定运行提供有力保障。