全程实时程线的冷链NEC的RFID解决方案帮助泰凌实现了国内领先的冷链管理系统

冷链必须是全程的 实时的 作为国内拥有雄厚实力的进口疫苗分销商,泰凌医药集团旗下的海南泰凌生物制品有限公司肩负着一些垒球知名厂商的疫苗产品在中国的分销和冷链配送服务.每当看到专用的冷藏车将一箱箱的疫苗运送到仓库的时候,泰凌人的心中感受到更多的是责任.     

收视价值的迷失 高端人群在远离卫视 2008目睹中国电视之怪现状

近两个月来,本刊网站的论坛里又不太安静。有个叫"高清迷"的香港网友遭到了广东一些网友的质疑。彼此论战的焦点大部分在说香港电视好看或不好看。"高清迷"网友说大陆电视越来越好,水平已经超过香港的电视节目。广东网友们则是缅怀香港电视的辉煌历史。这原本是简单的我说你好你说我好,互相捧场的事情,但是网络的奇妙性在于事情并没有朝积极的方向发展,其结果是吵架不可避免的发生了。外来的和尚是不是会念经,我们先不去管他。重要的是我们要弄清楚自己是怎么回事。本文,是专业电视人对我国各省卫视台做的调查评估。让我们了解一下我国的电视台的现状吧。     

ADSL服务

现在使用ADSL上宽带网的用户是越来越多了,对ADSL设备的维护也成了一个不容忽视的问题.只有维护保养好它,不但让你的"宽带之旅"省心又省力,还能延长其寿命.ADSL的维护可分为软件和硬件两个方面来分析,软件主要是PPPOE协议的问题,和计算机本身的气操作系统,和网卡方面的事情.硬件主要是局端的节点设备,和用户端猫的问题.还有通信的线路等一些因素.     

谁卡住了中国3G的脖子高通公司大中华区前总裁雷鸣告诉你鲜为人知的内幕

热闹了多年,也翻炒了多年,但中国的3G进程到现在仍处于一片迷茫当中。是谁卡住了中国3G进程的脖子？毫无疑问,部分跨国公司设置的高昂专利费是阻碍中国3G步伐前进的一块巨石。2005年4月23日,信息产业部副部长奚国华在参加2005年博鳌亚洲论坛年会时公开表示,跨国公司收取过高3G专利费这一行为导致3G进程缓慢,并呼吁这些跨国公司降低专利费用。奚国华副部长的一席话成为“3G专利谈判受阻”事件的最好注解。据悉,在这场关于WCDMA的专利费谈判过程中,高通公司在其他专利拥有者摩托罗拉、诺基亚、爱立信等同意降低专利费的情况下,谈判最终因高通公司的拒绝接受而搁浅。作为世界最大的通讯市场,中国通讯业的每一步进展都充满着坎坷;作为世界知名的通讯公司,高通公司已演变成CDMA生态圈里的巨鳄,其拥有的1400多项专利足以让人望而却步。这家出售知识产权的公司真的是阻拦中国3G进程的巨石吗?也许,从另一侧面观察,更能了解高通的真实面目。雷鸣先生是高通公司大中华区前总裁,他见证了高通的成长,更熟悉高通的一切事务。到底谁是卡住中国3G脖子的幕后主角?现在,经过雷鸣先生的观察和反思,一件件鲜为人知的事终于曝光在读者的面前。相信看完此文披露的诸多内幕,答案就在你的心中！     

电磁环境对人体健康的危害效应和剂量学中存在的若干问题

高频电磁辐射作用于人体后,一部分被反射,一部分会被人体吸收,被吸收的电磁能量使人体组织内的分子和电介质的偶极子产生振动,媒质的磨擦把动能变为热能,从而导致使人体产生温升的热效应.电磁辐射的功率、频率、波形、环境温度以及人体被照射的部位等因素影响热效应伤害的深度和程度.     

一种适用于协作多点联合传输的自适应PMI反馈方法

作为下一代无线通信系统的关键技术,协作多点传输能够有效降低相邻小区之间的干扰,提高小区边缘用户的频谱效率。在频分双工系统中,其性能依赖于各基站获取的基于有线反馈的信道状态信息的准确性。然而,所有协作基站都获得相同精确程度的信道状态信息会导致用户终端的反馈开销随着协作基站数线性增长。本文关注于如何在性能增益和反馈开销之间取得折中,提出一种适用于协作多点联合传输的自适应预编码矩阵索引反馈方法。用户终端根据不同协作基站下行链路的信道质量指示的相对大小,自适应的用不同的比特数表示不同强度链路的预编码矩阵索引,即用较多比特数表示具有较高信道质量指示的预编码矩阵索引,反之亦然。仿真结果表明,与传统反馈方案相比,该方法在几乎不牺牲频谱效率的前提下,大幅降低了反馈开销。      

中國精神六大重構之五传媒理念重构:信息开放的力量

汶川5·12大地震,这场突如其来的灾难让大半个中国遭受重创.我们每天被迫面对无数死伤的同胞和几乎被夷为平地的城市和村镇,悲痛欲绝的同时却又让我们达到空前的团结,5·12是悲惨的,也是悲壮的.我们感受到了全方位的力量,灾民、政府、同胞……尤其媒体的表现让所有人震撼,电视、广播、网络成为灾难的发言人,成为灾区与整个中国乃至全世界连接的信息生命线.     

ADSL用户需求解决方案

通信技术的进步推动了电信市场的发展,当前ADSL用户的需求旺盛,给北京通信的发展创造了有利的商机,同时也给我们带来一些急需解决的新课题,如何利用北京通信的传统优势克服发展瓶颈、充分满足ADSL市场的需要.本文首先分析了目前阻碍ADSL发展的原因,结合北京通信的实际情况提出了利用语音分配点安装OSLAM设备以解决瓶颈问题的新思路,然后介绍了新研制的多功能有源交接箱的设计特点和应用前景及用户纤光缆交换点的建立储备.最后对采用本文的思路和应用新设备的投资、回报等进行了经济性分析,从而系统完整地提出了一套可行的解决方案和相关实施建议.     

基于模式比较的漏洞分析技术研究

介绍了一种利用厂商发布的漏洞补丁信息分析漏洞细节的方法.该方法的关键是利用PE文件在安装补丁前后的不同,综合运用模式比较的方法建立模式匹配图,从而分析处漏洞的细节以及问题代码.该方法函数比较算法的清晰,以及模式图的差异的直观性,很容易分析出问题代码的位置,从而有效地提高了漏洞分析的成功率.     

追日

去年10月一个温暖的早晨,在澳大利亚内陆深处,14名麻省理工学院的学生和校友上午6点就爬出了他们的睡袋,准备车队,进行又一天的艰苦驾驶,在护卫队的护送下,他们驶过一段平坦、笔直、炎热、灰尘弥漫的道路.领头的车辆迎着其他车流,形成了一个缓冲带,一辆货车断后以监测整个队伍的进程.     

基于2007-2013年COSMIC掩星数据的电离层振幅闪烁研究

利用2007-2013年的COSMIC掩星数据，分析了E区与F区电离层闪烁的变化特征.发现用闪烁出现频次、闪烁发生率以及闪烁强度来表征的电离层闪烁出现规律比较相似.E区电离层闪烁在夏季半球的中纬地区最强，其次是春秋季的低纬地区和冬季半球.就经度分布来说，春秋季E区电离层闪烁呈四波结构.对F区电离层闪烁来说:南美-大西洋扇区在12月至点最为显著；非洲和太平洋扇区在6月至点最为显著；大西洋扇区在春秋分季最为显著.极区也出现中等强度的闪烁，尤其在南半球的90°E~180°E扇区较为显著.高纬E区电离层闪烁强度随太阳活动的增强而增强，而低纬和南半球的中纬E区闪烁随太阳活动的增强而减弱.高纬和低纬F区闪烁随太阳活动的增强而增强，而中纬F区电离层闪烁对太阳活动无显著依赖关系.对于赤道区来说，北半球60°W~60°E经度区闪烁强度随太阳活动的变化最为显著，其次是南半球60°E~210°E附近；而对于高纬地区来说，F区闪烁强度随太阳活动的变化最为显著的区域在南半球60°E~210°E附近.     

Fourth quarter 2009 IEEE communications surveys and tutorials

Welcome to the fourth issue of 2009 of the IEEE Communications Surveys and Tutorials. Paper in this issue survey the research effort in several areas such mobility in Wimax, mobility models in VANET, handoff in cellular networks, admission control in MANETS, physical impairments in optical networks, physical layer issues in the 802.11n standard as well as jamming in wireless sensor networks     

Inventive payoff from R&D in Japanese industry: convergencewith the West

An attempt is made to determine if investment in R&D and the hiring of college-educated employees result in a higher rate of inventions. The relationship between the input of R&D and inventive output is studied in two samples of Japanese factories, 34 in 1982 and 44 in 1970. These results are compared with findings in a parallel American study. The correlations between R&D and inventive output are similar in Japan and America in the 1980s, despite some differences in the management of innovation in the two nations. Moreover, the most Westernized subsample of Japanese firms in the 1970s had correlations between R&D and invention similar to those observed in the American study. Thus, it is concluded that some degree of convergence may be taking place in R&D management strategies in the two nations     

Effect of photovoltage on current flow in metal-semiconductor schottky-barrier contacts

It is shown that changes in device characteristics and an increase in the light-to-electrical energy conversion efficiency in metal-semiconductor Schottky barrier contacts are associated with a peripheral electric field built into the contact. For contacts with longer perimeters, variations in device characteristics and the light-to-electrical energy conversion efficiency are significantly larger. Since the photovoltage and peripheral electric fields in the contact region are codirected with the intrinsic electric field of the space-charge region, contact illumination results in a larger increase in the “dead” zone in forward portions of current-voltage characteristics, a larger decrease in the effective Schottky barrier height, and an increase in the field electron emission. An increase in the reverse field emission under photovoltage leads to an increase in the recombination current in the space-charge region, which provides dc photocurrent flow in the circuit.     

开放体系下云母表面纳米气泡的制备与观察

固/液界面纳米气泡的存在已经得到证实,并成为界面科学研究的一个焦点.在原子力显微镜液体池内制备纳米气泡的基础上,本研究建立了在开放体系中进行醇水替换,制备纳米气泡的方法.原子力显微镜观察显示.开放体系中进行醇水替换,也可以在水/云母界面上稳定地生成纳米气泡.将不同环境下制备的纳米气泡进行比较,统计结果显示,在开放体系下制备的纳米气泡密度较低,形态也较小.不同环境下醇水替换产生的纳米气泡数量和形态的差异,为纳米气泡形成的机制提供了新的佐证.开放体系下纳米气泡制备方法的建立拓展了纳米气泡的制备条件,揭示了纳米气泡存在的普遍性,同时也为纳米气泡性质研究提供了新的途径.     

Improved LUT Technique for HPA Nonlinear Pre-Distortion in OFDM Systems

In this paper, we focus on the Look-up Table (LUT) technique for the compensation of HPA nonlinear distortion. An improved LUT method is proposed with better performance compared with conventional LUT technique in terms of convergence speeds, BER and total degradation (TD). It can get over 8 dB gain in out-of-band spectrum re-growth suppression and about 0.3 dB BER performance gain than conventional LUT technique with the same iteration times. Also, we propose an actual application of HPA with pre-distorter in OFDM transmitter. Ai Bo was born in Shannxi Province in China on February 7, 1974. He received a BSc. Degree from Engineering Institute of Armed Police Force in 1997, a Master and Dr. degree from Xidian University in 2002 and 2004 in China respectively, and now working as a post dr. in Dept. of E&E, state of key lab. on microwave and digital communications in Tsinghua University in China. He has once participated in the key research project on HDTV in TEEG (Team of Engineering Expert Group) of China. He is an editorial committee member of journal of “Computer Simulations”, “Information and Electronic Engineering”, an IEEE member and a senior member of Electronics Institute of China (CIE). He has published over 60 scientific papers in his research area till now. His current interests are the research and applications of OFDM techniques with emphasis on synchronization and HPA linearization techniques. Yang Zhi-Xing graduated from Tsinghua University, P.R. China in 1970. He is now a Professor and Deputy Director of State Key Lab. on Microwave and Digital Communication at the Department of Electronic Engineering and the Director of the DTV R&D Center in Tsinghua University. As a DTV technical expert for the Chinese government, Professor Yang has also been a member of the DTV standardization Committee of China and a leader of the DTV Standardization Harmonizing Group in Ministry of Information Industry of China. His major research interests include broadband information transmission technologies and DTV broadcasting systems. Pan Chang-Yong received the B.S. and M.S. degrees from the Department of Electronic Engineering in Tsinghua University, P.R. China, in 1996 and 1999, respectively. He is now an associate professor in the Department of Electronic Engineering and a member of the DTV R&D Center in Tsinghua University. His research interests are in the areas of broadband wireless transmission systems and satellite communications. Zhang Tao-Tao was born in Shandong Province in China in 1982, he received BSc. degree from Tsinghua University in 2004 and now pursing his Master degree in Dept. of E&E, state of key lab. on microwave and digital communications in Tsinghua University in China. His research interests is the power amplifier linearization techniques. Wang Yong was born in Shannxi Province in China in 1976. He received a BSc., a Master and a Dr. Degree from Xidian University in China in 1997, 2002 and 2005, respectively, and now is an associate professor in Xidian University. He has once participated in the key research project on HDTV in TEEG (Team of Engineering Expert Group) in China and is an IEEE Member. His interests are broadband multimedia communications. Ge Jian-Hua was born in September, 1961 in JiangSu Province in China. He received the B.Sc., Master and Ph.D. degree from Xidian University in 1982, 1985 and 1989, respectively. He is now the professor in both Xidian University in Xi’an and Shanghai Jiaotong University in Shanghai. He is the senior member of Chinese Electronics Institute. He has won lots of scientific and technical prizes in China and published many papers. His interests are transmission communications and web security.     

A Strategy for Broad-Band Network Introduction in Italy

Studies are being carried out in Italy concerning the strategy for the introduction in the 1990's of optical fiber systems in the distribution network, in order to supply customers with broad-band services (in particular with video services). This paper deals with some of the main choices that are being done, in particular in view of a field trial which is planned in Rome in 1988.     

Changes in hemoglobin and ferritin biosynthesis in leukemias detected by M?ssbauer spectroscopy

The primary results of the study of hemoglobin and ferritin in erythrocytes in leukemia are considered in the light of the M?ssbauer spectroscopy data. The quantitative changes in hemoglobin and ferritin during differentiation of cells in the Friend erythroleukemia are shown. The qualitative changes in iron electronic structure of oxyhemoglobin in different forms of human leukemias are shown.     

Photovoltaics in architecture in The Netherlands: an architect's view

The Netherlands has a programme for the integration of photovoltaic (PV) modules in the built environment. The aim of this programme is to realize 250 MWp in PV systems by the year 2010. Within this programme the integration of PV modules in architecture has an important role, presenting opportunities for architects. New Technology and materials are an invitation for new design. BEAR Architecten is involved in several low-energy, bio-climatic building projects, amongst them are a few PV projects: De Kleine Aarde, an Environmental Education Centre with transparent PV panels in the glass roof; roof retrofit with PV modules in five houses in Leiden; facade integration with PV shading in 22 houses in Dordrecht; roof integration in row houses in Enschede; roof integration in a utility building in Geldermalsen. Information about these projects is given, but also the possibilities and the problems are discussed here. A general conclusion is that custom-made modules are often necessary to make well-designed buildings.     

微孔无铜原因分析与改善

文章主要分析了PCB制造过程中微孔出现孔无铜的各类原因以及改善预防措施,并且详细介绍了对于火山灰堵孔造成的微孔孔无铜的原因分析。