应用原子力显微镜对单晶硅进行纳米级加工

以原子力显微镜（AFM）作为加工工具,基于金刚石针尖对单晶硅进行了纳米加工实验,对纳米加工区域特性,材料在不同垂荷荷下的去除机理及切屑形成特征,进行了系统的研究和分析,提出了一种在纳米尺度下研究加工机理的新方法,在此基础上,应用有限元方法（FEM）对AFM纳米加工中存在于金刚石针尖和被加工材料之间的作用机制进行了计算仿真。     

微加工硅表面基于AFM的纳米压痕测量与分析

原子力显微镜(AFM)在完成对单晶硅的微加工后,其金刚石针尖被用做一个纳米压痕头以实现微加工区域内外机械性质的测量与分析.结果表明,以安装有金刚石针尖的AFM在经过化学机械抛光的硅基片上所进行的微加工,即使使用极小的切削力也会在加工表面形成变质层,但是其厚度值要小于化学机械抛光的硅表面变质层.由AFM测量的纳米级硬度值要大于由传统的Vickers和Hysitron 硬度测试仪所测量的值.另外,随着AFM压入载荷的减小,纳米级硬度值呈现出增加的趋势,这是由于在很小的压入载荷下所呈现出的压痕尺寸效应所导致.     

针尖扫描原子力显微镜的光点跟踪设计

提出了一种用于针尖扫描原子力显微镜(AFM)的光点跟踪设计方案,结构简单,容易实现。设计方案对扫描器的负载能力要求不高,而且能使原子力显微镜实现较大范围的针尖扫描。实验结果表明,采用此光点跟踪设计方案的针尖扫描原子力显微镜能实现最大100μm×100μm范围的扫描,z方向上的误差最大1 nm,能很好地满足大样品扫描的需要。     

基于隧道电流检测方式的原子力显微镜纳米检测系统设计

原子力显微镜（AFM）是当前进行材料表面微观形貌观察及分析的强有力工具之一。本文主要介绍一种隧道显微镜（STM）检测方式的原子力显微镜纳米检测系统（AFM.IPC-208B）,该AFM系统设计是在STM.IPC-205B系统设计的基础上,采用隧道电流工作方式,将STM与AFM功能组合兼容。文章详细阐述了AFM.IPC-208B系统的设计原理、镜体、扫描控制以及数据采集。新设计的AFM.IPC-208B系统仍具有0.1nm的分辨率,检测范围为0～2mm×2mm,系统操作简易,工作效率高,与原STM.IPC-205B系统兼容,工作性能稳定可靠。     

竖立在晶态金表面上的短单壁碳纳米管

合成和提纯了单壁碳纳米管(SWCNTs),用胶体将其竖直地组装在金薄膜表面上。用此组装技术制造了扫描隧道显微镜(STM)的针尖,成功地观测到了金晶粒的形貌像和高定向石墨的原子像。SWCNTs竖立在金表面上对于电学特性测量,制造场发射电子源,组装纳米电子器件,制作扫描探针显微镜(SPM)针尖等有重要意义。     

微加工硅表面基于AFM的纳米压痕测量与分析

原子力显微镜 (AFM )在完成对单晶硅的微加工后 ,其金刚石针尖被用做一个纳米压痕头以实现微加工区域内外机械性质的测量与分析。结果表明 ,以安装有金刚石针尖的AFM在经过化学机械抛光的硅基片上所进行的微加工 ,即使使用极小的切削力也会在加工表面形成变质层 ,但是其厚度值要小于化学机械抛光的硅表面变质层。由AFM测量的纳米级硬度值要大于由传统的Vickers和Hysitron硬度测试仪所测量的值。另外 ,随着AFM压入载荷的减小 ,纳米级硬度值呈现出增加的趋势 ,这是由于在很小的压入载荷下所呈现出的压痕尺寸效应所导致     

PMMA薄膜nm尺度下表面电荷的制备和观察

利用扫描探针显微镜(SPM)的导电探针在PMMA薄膜表面μm/nm尺度下通过摩擦方式产生了电荷,并用静电力显微镜(EFM)对生成的电荷进行了观察。讨论了生成电荷的极性、数量、区域大小与摩擦过程中探针加工速度、所加电压大小及正负之间的关系:产生电荷的极性与摩擦过程中针尖所加电压的正负保持一致,且所加电压越大,产生电荷的区域和面积越大。但相同情况下,PMMA表面出现的正电荷区域和数量要多于负电荷;针尖带电摩擦时,摩擦速度越快,产生电荷的数量和区域也随之减小。为探索PMMA表面电荷生成规律及生成机理提供了一种新的途径。     

基于原子力显微镜（AFM）的微小结构加工工艺研究

为了解决AFM单独用于机械刻蚀加工存在的局限性以及加工过程中各种因素对加工结果的影响等问题，提出一种基于AFM的非硅工艺微结构的加工方法。把三维微动工作台叠加到原子力显微镜工作台上组成新的微加工系统，采用金刚石针尖作为加工工具。根据AFM在线成像后的结果对该工艺过程中各种因素产生的影响进行了研究、分析和说明，得出主要参数优选的一般方法，讨论了与其他微机械加工方法相比较采用该方法的优缺点和可行性。应用该系统进行了微结构的加工实验，实验结果表明该系统能够实现较高尺寸精度和重复性精度的微结构的加工，并且通过优选参数改进工艺完全可以应用于微机械领域中诸如掩模或微尺度模具等简单和复杂的准三维或三维微小结构的加工。     

扫描探针显微学研究细胞的超微结构

利用近场光学显微镜(SNOM)和原子力显微镜(AFM)研究细胞的超微结构。SNOM对传统的光学分辨极限产生了革命性的突破,能够在纳米距离内探测光与样品物质之间的相互作用,在超高光学分辨率下对细胞成像,这种技术无侵入性和破坏性,能在细胞的自然状态下进行观测     

纳米材料的几种扫描探针显微表征方法

扫描探针显微镜（SPM）作为一种广泛应用的表面表征工具,不仅可以表征三维形貌,还能定量地研究表面的粗糙度、孔径大小和分布及颗粒尺寸,在许多学科均可发挥作用.以纳米材料为主要研究对象,综述了国外最新的几种扫描探针显微表征技术,包括扫描隧道显微镜（STM）、原子力显微镜（AFM）和近场扫描光学显微镜（SNOM）等方法,展示了这几种技术在纳米材料的结构和性能方面的应用.     

Trends in the standardization of telecommunications on GII,multimedia, and other network technologies and services

Global standardization is becoming more and more important in achieving a global information infrastructure (GII). Telecommunication and information standardization organizations such as the International Telecommunications Union (ITU) and International Organization for Standardization/International Electrotechnical Commission (ISO/IEC) Joint Technical Committee (JTC) have each set up special groups to focus on determining standards for GII. This article presents the activities of these organizations as they relate to GII. It also reviews the current status of standards for multimedia, asynchronous transfer mode (ATM)/broadband integrated services digital network (B-ISDN), Universal Personal Telecommunications (UPT), Future Public Land Mobile Telecommunication System (FPLMTS), and telecommunications management network (TMN), which are all key elements in GII     

Global standards

Pan-European standardization bodies and activities are discussed with particular attention given to their impact on international trade. Since many International Organization for Standardization (ISO) and International Electrotechnical Commission (IEC) standards have been derived from US and Japanese products, primarily in telecommunications, the fear that European standards may keep US companies out of the market is said by European experts to be largely unfounded. Of prime concern to the 12 European Community (EC) nations is whether they can generate standards fast enough to be of any benefit to the EC. Applying international standards is difficult because they are so complex. Because of the time (from two to ten years) and effort needed to generate standards, priority has been given to those that are important for safety and government procurement. The standardization process and funding and the role of the European Commission are examined     

扫描探针显微镜中数据格式的分析及转换程序的设计

随着扫探针显微镜技术发展和广泛应用,扫描探针显微镜的技术标准化问题在国内外受到越来越多的关注.然而在数据格式方面,由于所用硬件平台的不同等原因,各制造商所生产的扫描探针显微镜大多使用专用的数据格式.这些数据格式又往往互不兼容,给数据后续的分析处理和交流共享带来不便.本文首先对扫描探针显微镜中数据格式的发展及应用较多的格...     

Shaping future telecommunications: the challenge of globalstandardization

Rapid changes in telecommunication technologies and the telecommunications environment are presenting new opportunities and challenges to global telecommunication standardization. This article begins with a short introduction of the International Telecommunication Union (ITU), its structure and main responsibilities, before focusing on global standardization at ITU. But first one must take note of one important point: on March 1, 1993 a major structural reform of the ITU was implemented. Among other important changes, CCITT ceased to exist, and was resurrected as the new ``ITU Standardization Sector.' It is for this reason that the readers will find the term ``CCITT' used for the standardization activities up to February 28, 1993; after this date, the new term ``ITU Standardization Sector' (ITU-T) will be applied. The same situation exists for many other terms as well. It is hoped that the explanations provided in the text are clear enough to assist readers in understanding which new terms have come into use to replace the traditional terms that have been in use for so many years     

视频压缩编码国际标准综述

国际标准化组织和国际电信联盟制定了一系列视频压缩编码国际标准,有H.261,MPEG1,MPEG2, H.263, MPEG4和H.264等.该文分别对这些标准的技术特征和性能进行分析,并详细描述H.264中采用的视频编码新技术.     

Multimedia in the ODP-RM standard

To coordinate the various standards, we need a framework or architecture that covers many aspects of distributed systems without specifying implementation details. The International Standardization Organization (ISO), realizing the growing importance of standardizing distributed systems, initiated the Open Distributed Processing (ODP) standardization activity in 1987. The ODP reference model (ODP-RM) provides a general framework addressing distributed systems operating in a heterogeneous environment. This article presents ODP-RM and discusses its relevance to multimedia. The standard seeks to enable seamless interfacing of distributed application components despite their heterogeneity. The ODP-RM provides concepts, rules, and languages for building distributed systems. The ODP-RM is based on object orientation, communications, and distributed systems technology. It provides an overall framework for the design of open distributed systems     

Management and control of CCSDS cross-support services

A candidate architecture for management and control of Consultative Committee for Space Data Systems (CCSDS) services is presented. An operations concept is presented. Candidate management procedures and a management information base for the resources to be managed are suggested. This architecture is based on concepts of network management of computer and telecommunication networks which are under study by other international standards bodies such as the International Organization for Standardization (ISO) and the International Telephone and Telegraph Consultative Committee (CCITT)     

Toward a unified theory of managing large networks

The growing web of computer networks has triggered a search for an organizing principle to monitor and control operations. The various system management functions are identified, and the development of network management standards is discussed. Particular attention is given to the Basic Reference Model for Open Systems Interconnection (OSI), developed by the International Organization for Standardization (ISO)     

IEEE Recommended Practice: Rules for the Use of Units of the International System of Units

As a service to its members principle of international sta Standards Committee reviews recommendations, particularly those of the Interantional Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC), in its area of interest. This document is identical with ISO Recommendation R1000 except that in accordance with other IEEE recommendations the spellings ``kilogram,' ``meter,' ``liter,' and ``deka-' have been used in place of ``kilogramme,' ``metre,' ``litre,' and ``deca-.' ISO R1000 was drawn up by Technical Committee ISO/TC 12 (Quantities, Units, Symbols, Conversion Factors, and Conversion Tables) and was first published in 1969. It was reviewed and recommended for adoption by the IEEE Standards Coordinating Committee on Quantities and Units and was adopted by the IEEE Standards Committee on December 3, 1970. Comments concerning this document may be sent to the Secretary, IEEE Standards Committee, 345 East 47 Street, New York, N.Y. 10017.     

MPEG-4 high-efficiency AAC coding

The name MPEG-4 high-efficiency AAC (HE-AAC) refers to a family of recent audio coders that was developed by the International Organization for Standardization/International Electrotechnical Commission (ISO/IEC) Moving Picture Experts Group (MPEG) by subsequent extension of the established Advanced Audio Coding (AAC) architecture. These algorithmic extensions facilitate a significant increase in coding efficiency relative to previous standards and other known systems. Thus, they provide a representation for generic audio/music signals that offers high audio quality also to applications limited in transmission bandwidth or storage capacity, such as digital audio broadcasting and wireless music access for cellular phones. This article presents a compact overview of the evolution, technology, and performance of the MPEG-4 HE-AAC coding family.