基于3G通信网络的移动数字化校园建设研究

为了提高数字化校园网资源的利用率和改善高校学生的学习手段,介绍了一种基于3G移动通信网的数字化校园网--移动数字化校园网.在传统数字化校园网基础上,移动数字化校园网通过增设WAP内容服务器和WAP网关服务器,以3G移动通信网络为信息传递网,实现移动设备(手机)在"任何地方和任何时间在移动过程中与数字化校园网保持连续连接"的目标.     

移动数字化校园中流媒体的实现

为了提高数字化校园网的利用率和现代教育技术水平,本丈提出基于3G移动通信网的移动数字化校园网方案.结合校园网的IP协议和电信网的UMTS协议,提出了实现流媒体传输的协议栈,并且,通过分析一个主PDP上下文激活和两个次PDP上下文激活过程,介绍流媒体会话发起过程.利用微格教学方案,移动数字化校园网可以有效地为远程教育和移动学习服务.     

图书馆数字化管理体系构建

针对通过分析现行图书馆数字化管理体系的特点,阐述了其存在的不足。并针对制约图书馆信息资源港作用发挥问题。提出了一种图书馆数字化管理体系,通过标准化的数据库和软件架构,可实现资源共享、数据库对接,以扩充馆藏资源,并为今后的信息平台建设打好基础。     

浅论数字化图书馆

1　数字图书馆的体系结构1.1　数字图书馆的概念数字图书馆的概念是组织数字化信息及其技术进入图书馆并提供有效服务。几乎图书馆的所有载体的信息均能以数字化的形式获得 ,包括所有联机采购、编目、公共查询 ;对各种信息资源的检索 ,通过网络组织读者访问外界数字图书馆和文献信息数据库系统 ,如电子杂志 ,电子图书、声像资料、动画片、影视片、多媒体资料等 ;用计算机系统管理图书、期刊等的读者服务 ;图书馆和校园的网络 (或单位的网络 )连接到教室、办公室、实验室、甚至家庭和宿舍 ,让人们很方便地共享资源。从另一层意义而言 ,数字图书馆又称为虚拟图书馆 ,即在本地图书馆以外还有很多图书馆可被联机地访问 ,用户访问它们就向访问本地图书馆一样。许多电子信息中心 ,电子杂志中心等也将成为数字图书馆的重要成员。1.2　数字图书馆的特征数字图书馆的基本特征如下 :( 1)使用计算机将各种文献信息资源数字化 ;并用数字化信息提供网上服务 ;有些还能提供各种动画片、影视片、多媒体资料等的网上服务。( 2 )通过各种电子通信手段 ,特别是网络 ,连接各种信息服务中心和数字图书馆 ,包括地区、国家和国际上的信息数据库系统。( 3)使用新技...     

教学资源平台在数字化校园中的应用与实践

随着我国数字化技术的发展与应用,学校为满足学生学习与教师教学中的各种需求,在对信息与数字化技术充分应用的基础上,通过将各类型教学资源上传到校园网的上方式,来实现数字化教学资源平台的构建。本文就主要对数字化技术概念进行介绍,并详细分析教学资源平台在数字化校园中的应用与实践,再对其发展趋势进行研究,以期能够通过完善的教学资源平台,来促进数字化校园的科学、规范、合理建设。     

图书与情报工作

0005319信息数字化对图书馆工作的挑战[刊]/吴成英//信息工程学院学报.—1999,18(4).—60～61(A)论述了信息数字化给图书馆工作带来的挑战,认为只有提高图书馆工作人员的业务素质,才能主动迎接挑战,开创图书馆工作的新局面。参20005320     

网络环境下的数字化图书馆

21世纪将是一个全新的信息时代,图书馆在经历了传统图书馆、自动化图书馆之后,随着计算机技术、通讯和网络技术、高密度存储技术以及多媒体技术的飞速发展,人类正在向旨在建立有序的信息空间,实现真正意义上的信息资源共享为目标的新领域--数字化图书馆迈进.     

浅析构架安全的校园网络

近些年来,我国教育信息化快速发展。作为数字化校园的基础设施,校园网络建设也发展迅速。从刚开始的简单连接、到高性能冗余结构、再到认证计费广泛应用,校园网建设越来越普及。网上教学、网上办公、网上信息发布等校园网络信息服务越来越广,但校园网的安全问题也逐渐显现出来。但随着其应用的深入,校园网络的安全问题也逐渐突出,直接影响着学校的教学、管理、科研活动。如何构建一个安全高速的校园网络承载平台成为各高等院校越来越重视的问题。     

构建“云计算”数字化校园网解决方案探究

云计算作为一项迅速发展的信息技术目前已应用在国内外诸多领域,其强大的云服务能力将对高校数字化校园建设产生巨大影响和无限的机遇。通过对基于云计算的数字化校园网进行资源整合,以信息服务为切入点,构建高效、快捷的信息化服务体系,为高校信息化建设提供了新的解决思路。     

网络环境下的数字化图书馆

21世纪将是一个全新的信息时代,图书馆在经历了传统图书馆、自动化图书馆之后,随着计算机技术、通讯和网络技术、高密度存储技术以及多媒体技术的飞速发展,人类正在向旨在建立有序的信息空间,实现真正意义上的信息资源共享为目标的新领域－数字化图书馆迈进。     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.