Indolo[3,2-b]carbazole: Promising building block for highly efficient electroluminescent materials

Two luminescent materials based on indolo[3,2-b]carbazole have been designed and synthesized. They were highly fluorescent both in solution and in the solid state. High-performance electroluminescent devices with indolo[3,2-b]carbazole luminescent derivatives as the emissive materials were fabricated for the first time with low turn-on voltage of 2.65 V, high luminescence efficiency of 7.92 lm W^?1, and high brightness of 68729 cd m^?2. The results demonstrated that indolo[3,2-b]carbazole has great potentials as promising building block for highly efficient electroluminescent materials.     

无线局域网802.11a标准展望

无线局域网的时代已经来临电话可以轻而易举地摘掉电线，发展成为日下十分普及的移动电话。因此，毫不奇怪，无线技术在个人和商业计算领域也将日益流行起来。 802.11b（通常又称Wi-Fi）是现在最普及的无线标准之一，它在无线局域网（WLAN）领域已经占据绝对优势，而各行各业的商业客户也越来越多地将其视为一种通用连接替代技术。随着WLAN日益增多和广泛流行，802.11b规范必须支持越来越多需要大量带宽的应用，如，IP语音、视频数据流、视频会议，而WLAN所面临的最大挑战就是需要更强大的安全解决方案。802.11a标准的开发使更多无线…     

前景广阔的虚拟专用网业务

虚拟专用网是利用公众网资源为客户构成专用网 的一种业务。本文首先回顾了ＶＰＮ的发展简史，指出经济的全球化带动了ＶＰＮ的迅速发展，市场需求和技术发展是两大主要推动力。ＶＰＮ业务可使运营公司，电信客户和最终用户均能受益，其发展趋势是提供数据业务。最后简述了ＶＰＮ在我国的发展情况。     

三屏联动精准广告大有可为

目前,电信传媒业务是重要的转型业务之一。但目前电信传媒的媒体资源种类多但缺少强势的主流媒体,要想在目前竞争日益激烈的媒体广告市场上打响品牌,必须发挥电信自身资源的特点采取差异化策略建立差异化优势。     

埋入无源元件:促使改善性能

电子制造商把更多的功能压缩成更小、更便携的电子产品,这些电子产品已明显要求增加无源器件的数量。例如典型的奔腾Ⅲ母板(pentium Ⅲ matherboard)需要采用大约为2200个无源器件。而另一个例子是典型的蜂窝电话(call phone)所用印制板上的550个器件中无源器件占了500个。用于PC母板中的无源器件的增长数量和类型示于表1中。     

Exploring Promising Technology in ICT Sector Using Patent Network and Promising Index Based on Patent Information

This research proposes the use of a patent analysis methodology that can suggest promising technology in the ICT sector at the micro‐level. This approach identifies core patents from the technology field, groups them as research frontiers (RFs), and develops a visualized network based on the citing relationships to monitor the relationship among RFs. In addition, it calculates a “promising index” based on the growth potential, impact, and marketability of patents to ultimately derive promising RFs. To illustrate the proposed approach, this research presents analysis results for a chosen area, which is the user interface and user experience (UI/UX) technology field. By proposing promising technological fields at the micro‐level, the proposed methodology will serve as a useful decision‐making support tool in selecting R&D projects, technology planning, and determining technology policy direction.     

宽带固定无线接入技术及市场分析

本文综述了当前几种发展极为迅速的宽带固定无线接入技术，讨论了其演变过程及在国内的发展现状，并总结了无线接入在未来的主要发展趋势。     

EPON与GPON,小荷才露尖尖角

介绍了EPON与GPON两种技术。并从标准成熟度、支持速率等级和业务能力、传输效率、安全性和可扩展性等几个方面对EPON与GPON进行了比较。最后指出,EPON,GPON的发展尚需关注网络建设成本、运营维护成本以及完善产业链等问题。     

Mathematical Modeling of Promising Structures of Metal Oxides

Russian Microelectronics - Information about the structure and properties of materials is especially important when working with micro-and nanoscale objects due to the complexity of obtaining it....     

Promising Performance of PA-Coded SIMO FM-DCSK Communication Systems

Frequency-modulated differential chaos shift keying (FM-DCSK) is an attractive scheme which combines chaotic modulation with the spread-spectrum property. It is simple to implement and robust in multipath fading channels. A single-input multiple-output (SIMO) FM-DCSK architecture has recently been developed to increase data rate and achieve diversity gain. In this paper, several main channel coding schemes, i.e., error-correcting coding schemes, are introduced into the SIMO FM-DCSK communication system, with different code rates and different frame lengths, over multipath fading channels. It is found that, in contrast to low density parity check codes and convolutional codes, product accumulate (PA) codes can provide outstanding bit error rate performance improvement to the existing SIMO FM-DCSK system. In this paper, moreover, the optimum code rate for the PA-coded SIMO FM-DCSK system is investigated through simulations at a medium frame length. Because of its merits in several aspects, such as prominent advantages in better performance, simple encoding and decoding structures, and a flexibly adjustable code rate, this paper demonstrates that PA code is a strong candidate as the error-correcting scheme for the SIMO FM-DCSK system in transmitting medium and long frame lengths over multipath fading channels. This research was partially supported by the City University of Hong Kong under the SRG Grant 7002274, the Dept. of Education Administration of China (NCET-04-0601), NSFC (No. 60272005), as well as the Key Project of Science and Technology in Fujian Province of China (No. 2006H0039).     

推动三网融合 未来极具前景 IPTV得加油!

IPTV早在五六年前就出现了，近年来之所以成为关注的焦点，是因为IPTV代表着一个即将形成的、极具前景的产业。在国内，随着宽带的快速发展和用户群的扩大，宽带应用成为运营商关注的主要问题，IPTV也由此被推向了前台。     

ASON：光网络的新宠

随着全球数据业务的爆炸式增长，要求光传输网络提供更灵活的网络指配和高效快速的网络保护恢复能力，ASON技术的出现无疑是雪中送炭。     

Internet寻呼业务应用前景可观

随着Ｉｎｔｅｒｎｅｔ网络技术的发展,Ｉｎｔｅｒｎｅｔ用户和寻呼业务用户日益增多,Ｉｎｔｅｒｎｅｔ寻呼业务应运而生,Ｉｎｔｅｒｎｅｔ寻呼业务按使用方法可分为万维网寻呼和电子邮件寻呼两大类,目前提供电子邮件寻呼业务的公司较多。     

黑莓,3G市场的利器

随着网络通信的发展,人们对邮件的依赖越来越强。但是,依托于电脑终端的局限使其在带给我们方便的同时,也有很大的不便——无法实现随时随地的沟通。无线电子邮件可以帮助我们实现这一愿望,而黑莓作为无线电邮的代表性技术,将慢慢渗入人们的日常生活,并引领无线电子邮件的发展。     

一代前景诱人的新型器件——真空微电子管

描述了真空微电子器件的发展概况，特别对场发射阵列的结构设计进展、微波用场发射阵列研究、低压场发射阵列研究以及场发射平板显示器的现状进行了全面阐述。     

缅甸：湄公河畔的信息化沃土

从中国青海省唐古拉山发源，流经西藏自治区，由云南省南部西双版纳傣族自治州出境，于越南胡志明市附近注入南中国海；这条全长4880公里，在中国境内段被称为澜沧江，境外段称为湄公河的国际河流所流经的地区，也许是由于历史和地理的原因，竞都是清一色的发展中国家。例如缅甸、老挝、泰国、柬埔寨、越南。     

Navigational cosGBOC Signals in Promising Satellite Radio-Navigation Systems

The formation and structure of the modulation function (MF) of cosine generalized binary offset carrier (cosGBOC) signals applied in promising satellite radio-navigation systems, such as Galileo (European Union), global positioning system (GPS) (USA), and BeiDou/Compass (China), are discussed. Analytical expressions for the spectral density and energy spectrum characterizing the single components of cosGBOC-signal MFs are derived at the different values of pulse multiplicity coefficients N_R (N_R=2, 4, 6, …) and duty cycles ρ (ρ ∈ [0, 1]). The obtained general formulas for cosGBOC signals are employed to analyze spectra in the important particular cases of cosGBOC and BPSK signals. With the help of the Mathcad software package, the graphs of the energy spectra of the single components entering into the cosGBOC-signal MF are constructed for the following types of modulation: cosGBOC(1, 1, ρ), cosGBOC(2, 2, ρ), and cosGBOC(10, 5, ρ). The properties of the given energy spectra are investigated.     

MOS-Controlled Thyristor: A Study of a Promising Power-Switching Device

A type of MOS-controlled thyristor is designed, produced, and studied experimentally. Its static and switching characteristics are examined. The effect of electron irradiation on the characteristics is addressed. It is found that electron irradiation can significantly increase the maximum anode-current density.     

Promising acoustic-optical light filtering method for optical information-telecommunication systems

The opportunities of creating multifrequency matched acoustooptical (AO) light filters have been systematically investigated. It is revealed that these AO filters enable us to develop new principles underlying the construction of noncoherent optical code-division multiple-access systems and the hyperspectral sensors of Earth remote sensing systems with optimal predetection filtering of optical information.