基于粒子群的全空间瞬变电磁二维反演方法研究

针对煤矿实际采掘情况的复杂性,为了提高探测精度,为钻探提供有效靶点,为矿井水害防治提供可靠的地质资料,研究了基于粒子群的全空间瞬变电磁二维反演方法。通过建立Q型地电模型,开展基于时域有限差分的二维正演模拟,得到不同时刻各网格节点处的磁场强度值;抽取正演模拟得到的磁场强度值与实测资料中的磁场强度值进行最小二乘法反演,采用粒子群算法对电阻率和地层厚度参数进行寻优,使反演结果拟合误差满足精度要求;按测点号依次对最小二乘法反演后的磁场强度值进行全空间瞬变电磁二维反演计算,分析二维反演后得到的瞬变电磁场响应规律和反演精度。实际应用结果表明,基于粒子群的全空间瞬变电磁二维反演方法是可行的,反演结果中的低阻异常体具有成层特性及一定的连通性,更能反映层状地层以砂泥岩为主的岩性结构特征及含水特性,提高了探测精度和分辨率。     

瞬变电磁法地质勘探的仿真研究

针对优化地质勘探准确性问题,采用瞬变电磁法进行地质勘探,由于地质构造复杂,存在各种矿质材料.为优化探测,采用有限元分析软件ansys仿真半空间瞬变电磁场的传播特性,对比分析含高阻异常体、低阻异常体时线圈的响应数值,用瞬变电磁法对低阻异常体敏感程度好,并改变低阻异常体的埋深、尺寸、导电特性,对低阻异常体不同参数仿真分析,拟合相应的探测结果,得到相应的函数曲线.仿真结果表明:瞬变电磁法能比较灵敏地探测出低阻异常体,而对低矿质材料不能很好地区分,但对低阻异常体的阻值、尺寸和埋深是瞬变电磁法的探测效果较好.     

VB调用Matlab在瞬变电磁法反演中的应用

将VB调用Matlab方法应用到瞬变电磁反演中,介绍了利用ActiveX技术实现VB调用Matlab的详细编程步骤,以VB编写瞬变电磁法反演系统主界面,利用Matlab神经网络工具箱完成对瞬变电磁法探测结果的反演判释,两者相互取长补短,该系统具有良好人机交互界面,方便用户使用.实例验证结果表明,利用VB调用Matlab方法开发瞬变电磁法反演系统,其反演结果可信,且能够满足实际工程中超前探测的要求,反演结果能够用于指导工程施工.     

基于瞬变电磁法的电磁场矿藏解释仿真技术研究

将瞬变电磁法（Transient Electromagnetic Method,TEM）应用到布敦花铜矿矿区的解释中,首先需建立电磁感应模型,对瞬变电磁场中的二次磁场频率、时间特性进行分析,通过MATLAB软件进行程序编写,得出相应的特性曲线图。然后分别计算早、晚期视电阻率和全程视电阻率,得出瞬变电磁场在矿区变化时的视电阻率参数变化,得出相应的数据结论。最后,利用MATLAB的网格化函数,对数据进行处理,模拟出瞬变电磁场在铜区时的异常场变化,完成对矿区的解释。从结果分析可以看出,利用瞬变电磁法解释的结果比利用物探资料进行矿区解释的结果更简单、更精确。这样一来,既提高了工作效率,又提高了解释的准确率。     

基于并行直流电法和瞬变电磁的综合物探

为了提高井下工作面异常体勘探的准确度,详细叙述了直流电法和瞬变电磁物探技术的原理,并分析了各自的优缺点,初步探索了综合物探技术在提高探测质量中的应用。首先对一工作面进行直流电法的探测并反演成图,然后利用瞬变电磁技术对同一工作面进行探测并反演成图,最后找出直流电法和瞬变电磁技术反演成图中的共同异常区作为重点异常体。实验数据结果表示：综合物探技术更能突出工作区内异常体,更为准确地确定异常区的位置,对实际物探具有一定的指导意义。     

瞬变电磁法在山地变电站边坡接地网检测研究

接地网的完整对于电力系统的安全和可靠运行起到重要作用.实验地点的变电站建设在山丘上,由于边坡滑动的作用,北侧上下游挡土墙均出现了裂缝.采用瞬变电磁仪对变电站上下马道和边坡进行无损检测,通过对视电阻率成像图进行分析,反映出了实验地点的接地网结构状态.实例检测结果表明:瞬变电磁法能够高效、简便运用在在接地网无损检测.     

瞬变电磁信号降噪算法

研究地下异常体的有用信息,由于需要野外采集,所接收的瞬变电磁信号会叠加各种电磁干扰和噪声,而传统的降噪方法不能较好地对瞬变电磁接收的二次场衰减信号降噪,严重影响了利用信号对地下异常体特征的数据成图和地质状况解释.针对上述问题,提出了改进的基于独立成分分析的瞬变电磁接收信号降噪处理算法.由接收的瞬变电磁信号构成多维观测向量,利用独立成分分析方法从观测向量中分离出信号空间基向量,然后采用峰度判别准则对信号空间和噪声空间进行分离,保留二次场信号基向量,用二次场信号基向量张成信号子空间,实现降低噪声的目的.降噪后的瞬变电磁信号可以更好地反演出地下相关信息.通过对实测数据的验证,结果表明提出的算法应用于瞬变电磁法信号降噪是可行的,能有效地降低噪声并分离出二次场信号的有用信息,对提高瞬变电磁数据成图和地质状况解释质量具有较好的作用.     

三维梯度矢量瞬变电磁仪的建模及其仪器研制

为了探索和解决瞬变电磁物探在空间信息解析方面存在多解性问题,提出三分量梯度矢量瞬变电磁法模型和仪器方案,解决瞬变电磁探测深度的计算依赖于地层电导率和磁导率的问题。新型模型和仪器采集探测点的二次场三分量数据,得到其梯度矢量方向和大小,结合测点之间的距离和空间三角函数关系,计算出探测方向中低阻体的方位和距离。新型瞬变电磁仪在煤矿工作面的超前探测得到试用,验证预期效果,推广到物探工程应用中。     

物探实验成图与异常识别结果的分析与研究

基于瞬变电磁法的水体与云南省楚雄州腰站变电站物探实验.采用的设备为LTEM-1型瞬变电磁仪,其中,水体实验采用1条测线,12个测点的实验布局,变电站实验采用4条测线,平均32个测点的实验布局,利用改进的等值线图生成算法与异常区域识别算法对实验所得视电阻率数据进行了应用分析与研究.     

基于低温SQUID瞬变电磁系统的涡流补偿方法

为了避免瞬变电磁法TEM(Transient Electromagnetic Method)系统中的金属成分受发射场激发带来的涡流干扰,本文利用传输函数与发射场卷积获得系统涡流大小,并进行抵扣,以获得真实的地下响应信号。文中介绍了瞬变电磁法工作原理,描述了涡流形态及对SQUID接收信号的影响,同时建立了SQUID系统传输函数的测量装置,并对该传输函数的卷积效果进行了验证,确保卷积结果与实测结果一致。实验结果证明该涡流补偿方法可以应用于实际探矿工作中,提高了探测精准度。     

凹凸科技进军网络安全领域

2006年2月28日,网络安全及电源管理芯片供应商凹凸科技(O2Micro)向中国用户隆重推介凹凸科技在网络安全领域的独特理念和全新方案.此举标志着凹凸科技已正式进军网络安全领域.特别在ASIC防火墙和SSL VPN技术和产品的竞争中,凹凸科技已经担负了不可或缺的重要角色.而其在模拟与数字集成电路方面拥有的强大设计和制造能力,无疑将为其最终成为全球网络安全领域的主要供应商增加关键筹码.凹凸科技在评述中国安全市场发展趋势的同时,还将携两款最具代表性的成熟产品--ASIC防火墙SifoWorks和SSL VPN产品Succendo一起亮相.     

2006 Sun科技日在中国举行——"Java之父"James Gosling再来中国

继成功举办2005年Sun JAVA中国开发者大会之后,Sun一年一度全球规模的开发者大会——2006Sun科技日又分别于今年9月23～24日和27～28日相继在中国上海和北京两大都市举行“。Java之父”James Gosling再次来到中国,与中国的开发者讨论软件开发者所关心的问题,讲述Sun的软件发展策略、介绍Solaris10操作系统的独特的特性和新的Java开发工具、展望Java技术发展前景,特别是阐明Sun实施Java技术开源的策略。Sun科技日是Sun公司最重要的全球开发者的大会,它针对Java技术、Solaris10OS、NetBeans、OpenSolaris、开源技术、开发工具和Web…     

陕西省第一届国防科工系统内网安全研讨会召开

2006年3月15日,“陕西省第一届国防科工系统内网信息安全建设专题研讨会”在西安市隆重召开。此次会议的议题是,在当前的信息安全形势下,陕西省国防科工系统内网面临的信息安全问题,以及如何采取有效的解决方案进一步提高国家机要部门内部网络的安全保护等级,以适应形势发展的需要。此次会议由陕西省国防科工委主办,陕西省国防科工委信息中心和北京榕基网安科技有限公司、北京理工先河科技发展有限公司、陕西金叶西工大共同承办,国家保密局和陕西省国防科工委的有关领导出席会议并发表了重要讲话。在为期两天的会议中,共有100多名国防科工系…     

IT in teacher training in France

Abstract To understand what is going on in France at the moment in the domain of computers and related communication technologies in teacher training, there are two major developments that have to be kept in mind. Firstly, the ways of becoming a teacher in France underwent major changes in 1991. It is therefore too early to come to general conclusions about the effects of this reform in the field of new information technologies. Secondly, French IT in schools policy has shifted from a large-scale centralized equipment operation, which provided microcomputers in each school from 1985 to 1987, to a more regional management of equipment funding, with less national piloting in the field. This paper describes what happened during the previous period and what is taking place now. With matters still evolving the paper represents a snapshot rather than an exhaustive survey; such a survey remains to be done.     

Teacher education in IT in Germany

Abstract In 1988 the eleven West-German Kultusminister , with responsibility for the school systems in their respective Bundeslaender , reached agreement with the Federal Ministry of Education and Science on the broad concept of 'Information and Communications Technology', ITG. After four years of discussion it was agreed that ITG should be introduced into the secondary level of the general schools. In spite of strong disagreements about the ways and speed of implementation, and after several years of experiments, important parts of the concept have become a reality in practically all of the old Bundeslaender. While acknowledging the complexity of the German educational system the paper attempts to outline the development of the concept of Information and Communications Technology and its consequences in teacher education. The development in the eastern part of Germany, the former GDR, has been completely different to that in the western part and this is also commented upon in the paper.     

IT in teacher education in Scotland

Abstract This paper outlines the consensual approach to the formulation of curriculum policy in general, and in relation to information technology (IT) in particular, in Scotland. It outlines the approaches to IT that have emerged as a result. These are founded on the premises that all children should develop knowledge and understanding about IT and skills in using IT; that IT should influence both content and delivery of the curriculum; and that IT (computing studies in Scotland) should be an elective for secondary school pupils. Against this background, the paper describes the evolution of policy and practice relating to IT in teacher education. It appraises the strategies which institutes are using for developing the professional skills necessary to deliver IT in the Scottish curriculum. It notes significant progress but highlights the need to develop strategies which integrate IT more deeply with other professional studies so that student teachers develop deeper, more reflective approaches to IT.     

Informatics in teacher education in Japan

Abstract This paper charts the developments in information technology (IT) policies in education in Japan over the past decade with particular emphasis on the impacts on teacher education. Beginning with the work of the National Council on Educational Reform in 1985, the Japanese education system initiated a thorough analysis of the role of information technology in all aspects of education from kindergarten through to high school, vocational education and pre- and in-service teacher education. The various approaches culminated in guidelines and statutory requirements relating to both schools' curricula and teacher training, published in the period 1990–1992. More recently other ministries have contributed to developments including the Ministry for International Trade and Industry which has categorized the different types of information engineers and among these is the new Educational Engineer. The paper reports the processes leading to these developments.     

IT in teacher education in Denmark

Abstract As with many European countries Denmark is experiencing change in teacher education and most notably in the wake of an act of government in 1992 which was designed to set out common aims for teacher education. Prior to that the content and structure of teacher education had been highly specified including, for example, the requirement that student teachers should take a course of 42 hours IT-related lessons. This paper provides a brief history of the background to the changes in teacher education and focuses on the implications that the more flexible aims for teacher education have for the future integration of IT in teacher education.     

在网络层实现安全传输通道技术的研究

安全传输通道是对传输的原始信息进行加密和协议封装处理,从而实现安全传输的技术,本文在TCP/IP的网络层上提出了实现安全传输通道的技术和解决方案。并对网络层的安全传输通道技术提出了实现机制。     

Recent developments in ergonomics in China

Ergonomic thought and practice were introduced in ancient China in relation to modern developments in Chinese ergonomics. Despite the ten-year interruption of the 'cultural revolution’ in the late 1960s and 1970s, ergonomics has made great progress in China in the last decade. In this paper some general developments in recent ergonomics’ teaching and in professional organizations are described. Four major areas of ergonomics research are illustrated: (1) Visual displays and signal design; (2) Human-computer interface with Chinese computers; (3) Cognitive strategies and decision support; (4) Mental workload and occupational stress. The main characteristics of Chinese ergonomics are discussed and new directions are highlighted, based on recent developments and progress.