First engineering application of a 4,000m ocean floor survey successful

DTA-4000, a deeptow acoustic system jointly developed by researchers from the CAS Institute of Acoustics and their co-workers, has accomplished the task of examining an international submarine cable route in the northern part of South China Sea in last February. The system worked stably for 145 hours undersea, checking the cable for 640 km with plenty of reliable data.     

潜艇主要噪声源分离技术综述

潜艇主要噪声源的分离技术对于指导潜艇降噪措施的正确实施和辅助水下噪声系统的声学设计和噪声预报有着重要意义;本文从潜艇主要噪声源产生机理及其传播途径入手,讨论潜艇噪声源识别研究的特点;然后在综合分析国内外相关研究成果的基础上,给出一些潜艇主要噪声源分离技术前瞻。     

Information technology in rural emergency management

Abstract

Rural communities face a multitude of hazardous conditions—from blizzards, floods, droughts, and insect infestations caused by nature to hazardous material spills, transportation accidents, and dam failures that result from human activities. Information technology offers to rural emergency managers potentially important tools with which to better plan, alert, and respond to disasters.

Three case studies are presented about uses of different technologies. Each technology is currently in place, but not in widespread use. The first case is the use of a microcomputer in a rural Minnesota county to manage emergency resources, aid planning, and other important tasks. The second case uses cable television as a two‐way alerting link to fire, emergency medical, and police systems. The third case involves the use of satellites to form a statewide communication system among emergency service offices. Each use of information technology clearly contributes to improved emergency management, but widespread application is necessary before the full impact of information technology in rural emergency management can be felt.     

The use of alternating currents for submarine marine cable transmission

This paper contains the results of experiments performed by members of the Signal Corps Research Laboratory, Bureau of Standards, in an attempt to develop a method or methods of signal transmission over submarine cables which would permit of a more effective use of existing cable systems.In the method proposed and developed, signals are transmitted by means of alternating currents simultaneously with the normal battery of direct-current operation of the cable. Currents of several different frequencies may be used, reserving a given frequency for each message, and by tuning or equivalent methods at the receiving end these messages may be separated, so that the simultaneous transmission of a number of messages is redered possible.Accurate determination of the fundamental physical properties of a particular cable for different frequencies has been accompalished, and the results are given herewith. From these physical properties accurate calculations for any length of cable can be made, so that the design of proper apparatus becomes purely a laboratory problem.Actual trial of the proposed alternating-current method was made covering distances up to approximately 700 kilometres, with results which were in all cases completely satisfactory, indicating that the method is an entirely feasible one, and one which will render cables of this length, and undoubtedly of several times this length, much more useful.     

物理发泡挤出成型的关键工艺分析

随着移动通信行业的迅猛发展,同轴电缆的性能要求也越来越高。同轴电缆的材料、加工工艺等因素将对同轴电缆的性能产生直接的影响,文章主要分析了整个同轴电缆制造过程中最重要的物理发泡工序的关键工艺。     

浅谈光纤光缆和通信电缆技术的发展

综述了近期光纤光缆和通信电缆在制造、施工及维护技术上的发展特点,分析了其发展趋势,并就我国光纤光缆及通信电缆技术与产业的发展提出了一些值得思考的问题。     

有线电视数字机顶盒的关键技术

有线电视数字机顶盒的关键技术包括实时操作系统、中间件、加解扰技术及电缆调制解调等,这些技术使机顶盒向着多功能方向发展。     

天津子牙河大桥上部结构安装施工工艺

文章以天津子牙河大桥上部结构安装施工为例,说明自锚式悬索桥上部结构包括塔顶索鞍底板及索鞍安装;主缆施工工艺;吊杆安装的工艺及配套附属件的安装工艺。     

光缆线路维护与管理

光通信技术是最新电信技术之一，各种电信新业务几乎都是依托光纤传输网络发展的。光绳线路的日常维护比传统的电绳维护尤为重要，保证光网络高质量的运行，是保障通信畅通的重要环节。本文对光绳线路日常雏护、故障判断及抢修方法进行了阐述。     

Success in Failure: The National Centre for Popular Music

Abstract

The development and deployment of technologies for delivering broadband services to homes in Australia are investigated using the ‘social shaping of technology’ (SST) approach. The focus is on the period from 1993 to 1998 when there were five main technological options for delivering residential broadband services: ‘hybrid’ fibre coaxial (HFC) cable; direct broadcast satellite (DBS); multipoint microwave distribution systems (MDS); ‘Integrated Services Digital Network’ (ISDN); and ‘Asymmetric Digital Subscriber Line’ (ADSL). The main broadband services planned for delivery to homes over this period were pay television and fast Internet access. A sequence of snapshots of sociotechnical relationships at critical times during the study period, termed ‘sociotechnological configurations’, is used to track the evolutionary pathway of the broadband technologies. The mapping technique assists in identifying key features and explaining the driving factors of the pathway, including why HFC cable emerged as the predominant technology, and two competing HFC cable networks were rolled out in capital cities at an additional cost of over $2 billion when a single network would have had ample capacity.     

现代生物技术的物种特性及演化路径研究

以生态遗传学成种理论和技术进化论为理论依据,研究现代生物技术的形成和进化路径,一方面可以为技术的形成和演变增加研究角度,另一方面,也可从影响物种形成的因素分析过程中探寻生物技术演化的内在机理,为促进现代生物技术研究和发展,培育现代生物技术产业提供指导和借鉴。类比物种形成和成种机理,研究了现代生物技术所具有的拓展、派生和驱动等物种特性,总结了现代生物技术的形成机理和四种典型演化路径(,i)选择——渐进性创新过程中的技术自我强化;(ii)重组——技术的嫁接或融合;(iii)突变——产生于突破性创新的间断性技术;(iv)迁徙——现有技术应用到新领域。     

卸荷岩体锚固失效研究

介绍了边坡的分类以及在边坡支护中主要用到的支护方法。其中预应力锚索由于具有良好的工作性能而被广泛的应用在工程实践中。岩石锚固是预应力锚固技术应用中的一个重要组成部分,而其锚固效应的成败直接决定了边坡支护的成败。影响预应力锚索锚固效应的因素很多,如:岩体的应力状态、岩体岩性、锚固时间等。对卸荷岩体提出了其复杂的应力状态对锚固技术的影响。     

绿色革命揭开新篇章——生物技术应用于农业的成果和效益

生物技术——基因工程、细胞工程、酶工程和发酵工程,正广泛应用于农业领域:动植物良种培育、快速繁殖、动植物保护、固氮基因工程和土壤改善,以及农产品的深层次加工,并取得了明显的经济效益。生物技术是第二次绿色革命的先导技术,其应用于农业的特点和优势是:开发的层次深,应用的领域广,产出的效益高。     

Information technology and the developing world: Opportunities and obstacles

Abstract

The developing countries, although not homogeneous, share a growing recognition of the importance of information technology for fostering the development process. Rapid advancements in computer and telecommunications technologies offer new opportunities for improved resource management and for the successful employment of these tools in rural areas. Although developing nations have responded enthusiastically to the advantages of modem information technology, they are equally cognizant of the negative impact that reliance on foreign technology and services may have. As a result, developing countries are taking a number of actions—at the national, regional, and international levels—to ensure their active participation in the emerging Information Age.     

激光焊接技术在金属带接带中的应用

射频同轴电缆在生产外导体时广泛采用焊接方式对接铝带、铜带,以此来解决来料定长不标准、不符合订单定长要求的问题,当前使用最广泛的焊接技术是氩弧焊对接技术,而本文所述,随着激光科学的发展和普及,激光焊接带技术,应用到金属接带中成为一种更新、更好的技术。     

Java MIDP平台下蓝牙通信软件设计

蓝牙是一种低成本、低能耗、小范围的无线通信技术,主要用途是为移动设备(手机、PDA和其他便携设备)提供相互通信的能力。蓝牙并非是一项新的技术,但利用Java在MIDP平台下开发蓝牙应用程序却是一项新的技术。为了在JavaMIDP平台下开发支持蓝牙技术的软件,JCP定义了JSR82标准--Java蓝牙无线技术APIs(JABWT)。本文阐述了如何使用JABWT设计蓝牙应用程序,并对串口仿真协议(RFCOMM)进行了详细的分析和深入的研究,然后应用RFCOMM协议在JavaMIDP平台下开发了蓝牙通信应用程序。     

光通信网技术研究

本文介绍了电通信网向光通信网转变的必然趋势,对于光通信网络的关键技术、结构特征和未来发展作了详细阐述。     

海底管道失效原因分析及其对策

海底管道作为海上油气田的生命线，在海洋石油开发中发挥着重要作用．但恶劣的工作条件使海底管道经常因腐蚀、波流冲刷、机械破坏等原因而失效，海底管道的安全一直是人们关注的问题．文中对海底管道失效的主要原因进行了分析，同时也从选线、设计等多方面提出了防止海底管道失效的对策，并对海底管道检测方法进行了简单介绍．     

苏联技术向中国转移的特点及其影响

20世纪50年代至60年代初,苏联技术向中国进行了一次成功的转移。这次技术转移是一种混合式的技术转移,一种属于社会主义大家庭内部的有偿的技术转移。它通过三种途径得以实现———援建工业项目、进行科学技术合作、帮助建立和调整高等院校以及中等技术学校并吸收大量留学生和进修生。本文分析了这次技术转移的特点及其对中国的影响,认为它所转移的技术基本上比较先进,符合中国国情,大致上属于适宜技术,是新中国长期的技术老本。文章得出如下结论:这次技术转移推动了现代技术向中国进行大规模的、系统的、水平较高的转移,奠定了中国现代技术和工业化的基础,初步构建了比较完整的现代技术和工业体系,带动了科学研究的发展,形成"以任务带学科"的发展模式,对20世纪中国社会发展产生了深远的影响。     

技术发展的两种趋势

自主技术论是技术决定论的变种,在技术哲学和技术社会学中占有重要的理论地位。本文全面分析了自主技术论的基本观点及其有价值的方面,指出了它的片面性和局限性.在此基础上,本文认为,技术的自然属性决定了技术的自主发展规律,技术和社会属性决定了技术的非自主发展规律.技术的自主发展指技术系统内部存在的逻辑规律性,不受外部条件和环境影响;技术的非自主发展指社会因素限制了技术的发展速度、方向和规模,在宏观整体、中观群体和微观个体三个层次上对技术施加作用。技术的两种发展趋势在不同的历史时期具有不同的特点,第二次世界大战以后,这两种发展趋势有机地结合起来。在体制改革时期,应致力于协调科技体制与政治、经济和文化体制之间的关系,有效地实现技术的社会控制,应该建立一种具有特殊功能的组织机构——技术的社会建制.