基于三维激光扫描技术的爆破对象数字化研究

爆破对象的数字化,是整个爆破过程数字化的基础。三维激光扫描技术首先快速、准确获取物体表面点的三维坐标数据,然后由点云构建出物体的立体模型。介绍了采用三维激光扫描技术实现爆破对象数字化的过程,包括:爆破对象数字化模型建立、爆破设计数字化、爆破效果数字化和爆破质量控制数字化。     

三维摄影测量用于露天深孔爆破设计初探

精细爆破要求精确控制炸药爆炸能量释放与介质破碎和抛掷的过程。为了实现精细爆破的要求,需要有准确的地形资料、先进的设计方法以及精确的理论计算和数值模拟。采用ShapeMetrix3D三维摄影测量系统为获得准确的爆区三维地形资料并建立最初的三维模型提供了有效的工具。基于Windows开发环境,利用ShapeMetrix3D三维摄影测量系统获得三维地形资料并建立地形数据库,以C#作为开发工具,开发了能够实现深孔布置、深孔三维坐标获取、装药量计算等功能的露天深孔爆破设计系统,为精细爆破提供了先进的设计平台。系统可以准确地再现爆区的地形地质条件,实现人机交互爆破设计,准确地确定孔位、孔网参数和爆破药量,使爆破效果和爆破有害效应得到有效的控制,最终实现安全可靠、绿色环保及经济合理的爆破作业。     

基于GPS的智能化设计在露天石灰石矿山爆破中的应用

传统露天矿山爆破设计与施工多基于爆破作业人员的经验或工程类比法实施,普遍存在设计偏差大、钻孔精度低、爆破大块多等问题。为提高台阶爆破工程中设计与施工的匹配度,减少人工、材料和机械的浪费,有效改进爆破效果,开发了一套智能化台阶爆破设计优化系统软件,该软件具有台阶爆破设计、爆堆块度分布统计分析、爆破振动分析与预测、爆破效果综合评价等模块功能,软件使用过程中基于高精度GPS测量技术,提取爆破对象原始数据完成自适应设计,并将设计成果导出到施工现场。以贵州某水泥厂露天石灰石矿山开采为例,运用GPS采集当前采矿区域地形数据,结合现场实际进行台阶爆破智能化设计,再通过GPS技术将设计数据精确反馈到施工现场,指导现场施工。结果表明,智能化设计软件自适应能力强,采用基于GPS的智能化设计,提高了设计和钻孔的准确度,降低大块率33%,改善爆破效果显著,实现了设计与施工的精细管理,达到安全、经济、高效采矿的目的。     

精准控制钻孔角度的定向装置研究

光面(预裂)爆破效果好坏主要取决于钻孔的平行度,钻孔前方便、快捷、精确地测量和调节钻杆姿态是关键.为此将一种先进的高精度电子罗盘安装在钻架臂上,随时监测钻臂的三维姿态,使钻孔方向处于被监控状态,方便及时调整钻孔方向误差,保证钻孔平行度达到设计要求.与国外开发的GPS测向装置相比不仅成本低,且克服了GPS受卫星信号强弱影...     

基于三维巷道模型的深孔爆破扇形布孔优化设计

为了满足生产实际并提升深孔爆破布孔优化设计的效率,介绍了三维巷道模型的构建及切割方法,并在此基础上通过3种方法对比选择出基于Dij kstra算法建立深孔爆破扇形炮孔排面优化设计算法模型,在Auto CAD平台进行二次开发深孔爆破炮孔优化设计程序模块,并成功应用于某铁矿.深孔爆破优化设计程序的开发,解决了炮孔布置方案中...     

爆破荷载作用下岩石边坡动态响应的FLAC3D模拟研究

已有的岩石边坡爆破动力响应分析多用有限单元法.作者尝试运用FLAC3D的动力分析模块进行岩石边坡爆破动力响应分析.建立了能够反映主要地质构造的三维岩石边坡数值模型.介绍了三维有限差分程序FLAC3D动力分析的理论基础,包括边界条件的设定、动力荷载的输入、阻尼的选取以及岩体本构模型的选择.采用FLAC3D模拟了该岩石边坡在爆破荷载作用下的动态响应.分析了爆破结束后边坡体内位移场、应力场、速度场以及塑性区的分布情况,并与爆破前进行对比.将计算结果与实测数据进行了比较,结果表明FLAC3D用于爆破荷载作用下岩石边坡动态响应的数值模拟是可行的.     

三维数字化爆破质量评价技术

爆破质量的全面定量检测和评价是推动精细化爆破的基础。三维激光扫描技术具有快速、准确和区域整体测绘的特点,为高效、定量检测和评价爆破质量提供了技术手段。采用三维激光扫描技术对爆后结构面和爆堆形态进行扫描,建立三维实景数字模型,然后在三维实景模型中进行几何测量和质量评价。研究内容包括爆破结构面、爆堆形态的现场三维激光扫描、三维实景数字化模型建立、爆破质量立体检测和爆破质量评价。研究表明,三维激光扫描技术具备精细化管理的全面质量检测和评价能力,为实现爆破数字化和智能化提供数据基础。     

三维数字化爆破质量评价技术

爆破质量的全面定量检测和评价是推动精细化爆破的基础。三维激光扫描技术具有快速、准确和区域整体测绘的特点,为高效、定量检测和评价爆破质量提供了技术手段。采用三维激光扫描技术对爆后结构面和爆堆形态进行扫描,建立三维实景数字模型,然后在三维实景模型中进行几何测量和质量评价。研究内容包括爆破结构面、爆堆形态的现场三维激光扫描、三维实景数字化模型建立、爆破质量立体检测和爆破质量评价。研究表明,三维激光扫描技术具备精细化管理的全面质量检测和评价能力,为实现爆破数字化和智能化提供数据基础。     

基于神经网络的台阶爆破参数优化设计

台阶爆破技术作为一种破碎岩石的方法,广泛应用于矿山、水利水电工程、交通工程、土建工程等领域,而由于爆破对象及爆破过程的复杂性和不确定性,很难用一套统一的计算公式来完成爆破设计.充分利用神经网络的特点,利用BP神经网络建立台阶爆破设计优化模型,将已有的成功实例输入模型,采用Maflab对模型训练,使模型的传递函数相关系数趋于最优,最后将模型应用于实际爆破工程,结果表明,该方法具有一定的实际应用价值和工程指导意义.     

近景摄影测量技术在台阶爆破可视化中的应用

爆破可视化是爆破设计结果三维可视化显示和爆破施工过程的仿真模拟.基于爆破可视化技术的研究现状,分析了其关键技术三维地质建模的方法和特点,针对该技术存在的获取资料难、建模周期长、精度差等问题,引入近景摄影测量技术.分析了近景摄影测量建模高效、操作简单的优势,介绍了利用该技术获取地形地质资料的步骤,讨论了其在爆破可视化中的应用.     

Flow-Induced Instabilities in Pump-Turbines in China

The stability of pump-turbines is of great importance to the operation of pumped storage power (PSP) stations. Both hydraulic instabilities and operational instabilities have been reported in PSP stations in China. In order to provide a reference to the engineers and scientists working on pump-turbines, this paper summarizes the hydraulic instabilities and performance characteristics that promote the operational instabilities encountered in pump-turbine operations in China. Definitions, analytical methods, numerical and experimental studies, and main results are clarified. Precautions and countermeasures are also provided based on a literature review. The gaps between present studies and the need for engineering practice are pointed out.     

Differences in coagulation in clotting of vascular access in hemodialysis patients

Arteriovenous graft (AVG) thrombosis is a frequent cause of graft failure. We evaluated coagulation protein concentrations, platelet function, and viscoelasticity factors in 20 hemodialysis (HD) patients with AVGs. The goal was to determine whether significant differences in protein concentrations, platelet function, and viscoelasticity factors exist among dialysis patients requiring frequent AVG declot procedures vs. those who do not. Twenty HD patients were enrolled: 10 frequent clotters (>3 declots in the previous year) and 10 were nonclotters. Patients on antiplatelets or chronic anticoagulation were excluded. Laboratories were drawn pretreatment and heparinase was added to counteract any potential heparin effect. Coagulation protein concentrations including tissue factor (TF), thrombin/antithrombin III complex (TAT), and prothrombin fragment 1 + 2 (F₁₊₂) were assayed. The time to clot onset was measured by force onset time (FOT). Platelet contractile force (PCF) measured the force produced by platelets during clot retraction, whereas clot rigidity was measured as clot elastic modulus (CEM). FOT, CEM, and PCF were measured by Hemodyne. Both groups had upregulation of the TF pathway, as TF, TAT, and F₁₊₂ levels were similarly increased over baseline levels. Hemodialysis patients with frequent AVG clotting had higher levels of both PCF and CEM compared with nonclotters. Additionally, the frequent clotters had a lower FOT relative to nonclotters, although both were considered in the normal range. Our study suggests that HD patients with recurrent AVG thrombotic events form clots with higher tensile strength compared with HD patients without recurrent graft thrombosis.     

Trends in alcohol-impaired driving in Canada

While a general decreasing trend in the number of persons killed in a traffic crash involving a drinking driver has occurred in Canada since the 1980s, it is evident that much of this decrease occurred in the 1990s. Since 2002, less progress has been made as the number of persons killed in crashes involving drinking drivers remains high. To better understand the current situation, this paper describes trends in drinking and driving in Canada from 1998 to 2011 using multiple indicators based on data collected for the Traffic Injury Research Foundation's (TIRF) Road Safety Monitor (RSM), the National Opinion Poll on Drinking and Driving, and trends in alcohol-related crashes based on data collected for TIRF's national Fatality Database in Canada. There has been a continued and consistent decrease in the number of fatalities involving a drinking driver in Canada. This remains true when looking at the number of fatalities involving a drinking driver per 100,000 population and per 100,000 licensed drivers. This decreasing trend is also still apparent when considering the percentage of persons killed in a traffic crash in Canada involving a drinking driver although less pronounced. Data from the RSM further show that the percentage of those who reported driving after they thought they were over the legal limit has also declined. However, regardless of the apparent decreasing trend in drinking driving fatalities and behaviour, reductions have been relatively modest, and fatalities in crashes involving drivers who have consumed alcohol remain high at unacceptable levels.     

Gender differences in publication productivity in psychology in India

An analysis of gender differences in psychology in India provides quantitative and qualitative assessment of R&D output contributed by psychologists with the indication of the trend of growth, skewness, relatedness, co-authorship pattern of productivity.     

离子液体中电沉积的研究进展

离子液体作为绿色溶剂和可设计性溶剂越来越受到重视.对电沉积来说,离子液体融合了高温熔盐和水溶液的优点.分别综述了AlCl3型离子液体、非AlCl3型离子液体和其他新型离子液体3类离子液体中电沉积的研究现状,在此基础上指出了目前尚存在的问题及今后的研究方向.采用离子液体进行电沉积能克服传统水溶液电沉积时存在的缺点,为电沉积领域找到了新的突破点,是一种很有应用前景的方法.     

高聚物银纹化的研究进展

结合最新的研究进展,对银纹引发、生长与断裂,银纹细观结构以及裂纹在银纹中的扩展等问题作了较全面的介绍和分析,对这一领域未来的研究方向和重点进行了展望。     

铁电陶瓷中电畴翻转研究进展

电畴为铁电陶瓷固有的独特微观组织特征之一,铁电陶瓷的许多性能均与其密切有关.综述了铁电陶瓷中的电畴结构,系统介绍了电场、机械作用引起的电畴翻转,概述了电畴翻转对铁电陶瓷断裂韧性的影响及其研究进展.     

Standardization in the Cultural Heritage in China

China has begun its standardization process in the cultural heritage since 1960.The standards contributed a lot to the development of the heritage conservation practices. In this paper, the author summaries the existing condition of standardization in the cultural heritages and museums field in China, and presents Standards for the Classification of Collected Cultural Heritages. Also this paper points out the problems which exist in the standardization in the cultural heritage, and gives the advice to solve these problems.