矿井瞬变电磁法定向超前探测机理及方法研究

巷道掘进前方隐伏的导、含水构造或老窑采空积水区极易造成矿井突水事故,对煤矿安全生产构成极大威胁。研究定向超前探测技术,准确及时地预报掘进前方隐伏的赋水构造,对于煤矿的防治水工作与安全生产具有重要意义。本文首先通过数值模拟分析了磁偶源平行层理激发方式下全空间瞬变电场的扩散衰减过程,得到了不同地电断面瞬变磁场的响应特征,分析了矿井瞬变电磁定向超前探测的原理,在此基础上研究了瞬变电磁定向探测的数据采集与处理技术。最后通过实例分析,说明矿井瞬变电磁法定向超前探测技术对老窑采空积水区和巷道前方断层的探测取得了好的应用效果。     

瞬变电磁法在深部巷道底板超前探水中的应用

矿井瞬变电磁法作为一种非接触式探测技术,在煤矿水害探查中发挥着重要的作用。本文系统介绍了矿井瞬变电磁场探测技术的基本原理和基于"烟圈效应"理论的视电阻率计算和时深转换;并采用适合巷道探测环境的测量装置和施工方法对深部巷道底板进行超前探测,通过实际钻孔验证取得良好的探测效果。     

瞬变电磁法在邢台矿71101工作面探测底板富水性的应用

本文介绍了瞬变电磁法在邢台矿探测71101工作面底板富水性的应用效果及探采对比情况,实际揭露资料验证说明,该方法用来探测煤层底板富水位置是比较准确的,能为矿井水害预防及治理提供技术保障。     

基于Matlab的矿井瞬变电磁超前探测三维显示技术

目前,矿井瞬变电磁超前探测的成果图都只是二维显示,但是,地下是全空间的,用电磁法探测到的信息是整个立体空间中的介质的综合影响,所以数据资料的二维成图显示难以描述三维空间的地质信息。本文简要介绍了自编的基于Matlab的矿井瞬变电磁三维显示程序,实现了对矿井瞬变电磁超前探测三维数据体的可视化,展示了各种功能成图的效果,比较直观、形象地显示出异常的位置及范围。     

瞬变电磁技术在矿井小窑破坏区内寻找煤炭资源中的应用

瞬变电磁法是目前应用较广的矿井物探工作方法之一,该方法观测纯二次场,故分辨率高,可分辨出地下规模较小的不均匀体,尤其对低阻地质体反应灵敏。本文将瞬变电磁法用于云冈矿小窑破坏区的探测及范围圈定,取得良好的效果,为煤矿在小窑破坏区内寻找可采资源,延续矿井寿命提供了技术基础。     

瞬变电磁法在谢桥矿13-1煤层顶板砂岩裂隙水防治中的应用

在矿井防治水工作中,煤层顶板砂岩水的防治一直是防治水工作中的难点,具有探测难,疏放难。为保证工作面正常开采,在煤层开采之前进行水文地质勘查,查明煤层顶板围岩的富水情况具有十分重要的意义[1-2]。谢桥煤矿13-1煤层底板砂岩水具有赋水区域分布广,突水量大的特点,瞬变电磁法的应用,解决了探测难的问题,为矿井13-1煤层顶板砂岩水的探测提供了理论依据。     

某地下工程涌水分析及处治

本文对某地下工程的工作面涌水情况进行了无线电波透视、三维直流电法、音频电透视法及瞬变电磁法等相关的地球物理探测工作,同时对涌水区及其周边三维地震数据进行了分析解释,并结合定向钻孔明确了导水通道的位置和范围;通过布置钻孔注浆及相应效果检查验证的方法有效解决了工程问题,并为后续安全施工提供了保障。     

瞬变电磁在探测采空区中的应用

地下煤层采空后形成的采空区,使矿山安全面临很大的安全问题,本文利用瞬变电磁法来探测采空区的存在,重点阐述瞬变电磁法的原理,并应用于实际采空区中的探测,检验应用效果。     

瞬变电磁虚拟波场成像方法在煤矿井下精细探测中的应用

矿井瞬变电磁法凭借对低阻体敏感、方向性好、施工便捷的优势,是当前煤矿水害探查的重要方法,但同时也存在着体积效应明显、精细成像能力差的问题。本文探讨了瞬变电磁波场变换理论,实现了对瞬变电磁信号中波场特性的提取,提出了基于虚拟波场波形特征的速度分析反演成像方法。通过工程试验,对利用瞬变电磁虚拟波场反演成像方法对常规瞬变电磁探测数据进行精细解释的实用性和可靠性进行了检验。研究表明:瞬变电磁虚拟波场反演成像方法能够有效减小瞬变电磁超前探测体积效应、提高解释精度。     

瞬变电磁法在谢一矿井下超前探测灰岩水中的应用

利用瞬变电磁全空间效应探测技术,探测介质之间存在的电阻率差异,实现超前探测巷道前方灰岩富水区域和范围,为矿井水害预报和防治提供可靠的依据。     

To serve and promote science development via innovation

CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing.     

Students' Reactions to the Introduction of Videoconferencing for Classroom Instruction

This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors.     

Tracing the origin and early radiation of birds——Paleornithologist ZHOU Zhonghe

With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants."     

Cooler temperatures inductive to locust outbreaks

Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007.     

Exploring Multiplexity: Social Network Structures in a Computer-Supported Distance Learning Class

A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction.     

The Role of Intermediating Institutions in the Diffusion of Electronic Data Interchange (EDI): How Industry Associations Intervened in Denmark, Finland, and Hong Kong

Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies.     

How Electronic Publishers are Protecting Against Piracy: Doubts About Technical Systems of Protection

The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means.     

Rough Justice: A Statistical Assessment of ICANN's Uniform Dispute Resolution Policy

Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP.     

Prevalence of soft neurological signs in Chinese people

Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.     

Stern-Gerlach effect goes chiral

Prof. SUN Changpu from the CAS Institute of Theoretical Physics and coworkers from University of Basel in Switzerland have worked out a way --at least in theory --to split a beam of molecules according to their chirality. The technique involves passing the molecules through three different laser beams and is similar to the famous Stern-Gerlach effect, whereby a beam of atoms passing through a magnetic field is split in two according to the atoms＇ spin states （Phys. Rev. Lett. 99 130403）.