基于VPN企业办公系统的设计及实现

虚拟专用网络（VPN：Virtual Private Networks）是Internet技术迅速发展的产物，能提供与专网类似的安全性，可靠性，优先级别和可管理性，为企业内部的工作和业务流程自动化、信息化提供了网络平台，首先介绍了VPN的基本原理，提出了一种基于VPN技术的办公系统设计方案，给出了基于VPN技术实现企业办公的网络平台规划、软件平台规划和全网的安全保护措施，为企业实现“扁平化”管理提供物理平台，利用群件系统实现日常办公流程、工作流程，为企业实现EPR打下基础。     

基于VPN技术企业办公系统的设计及实现

虚拟专用网络 (VPN:Virtual Private Networks)是 Internet技术迅速发展的产物 ,能提供与专网类似的安全性、可靠性、优先级别和可管理性 ,为企业内部的工作和业务流程自动化、信息化提供了网络平台。首先介绍了 VPN的基本原理 ,提出了一种基于 VPN技术的办公系统设计方案 ,给出了基于 VPN技术实现企业办公的网络平台规划、软件平台规划和全网的安全保护措施 ,为企业实现“扁平化”管理提供物理平台 ,利用群件系统实现日常办公流程、工作流程 ,为企业实现 ERP打下了基础。     

基于VPN远程访问Intranet的实现

利用VPN技术，可以在现有的公用网络平台上构筑不受地域限制而受企业统一策略控制和管理的Intranet。本文从VPN的基本概念出发，探讨了其基本特征和解决方案，并给出了利用VPN技术远程访问NT局域网的实现过程。     

基层体工大队网络平台的规划与设计

设计和规划了一个通用网络平台，即可以满足体工大队对因特网信息的需求，又可以提供安全的运行环境供内部信息管理系统使用。该网络平台综合使用有线网和无线网技术，确保网络的可用性和稳定性。同时，应用防火墙技术、三层交换技术和VPN功能组建网络，即保证了网络的相对安全性，也方便员工的使用，从而更好地为基层体工大队提供一个良好的信息交换平台。     

校园网建设规划

校园网是利用现代网络技术、多媒体技术等为基础建立起来的计算机网络，为学校的教学、管理、办公、信息交流和通讯等提供综合的网络平台。文章就校园网总体建设规划、网络安全平台建设和校园网功能实现三方面进行了简要介绍。     

浅谈校园网建设规划

校园网是利用现代网络技术、多媒体技术及Internet技术等为基础建立起来的计算机网络，为学校的教学、管理、办公、信息交流和通讯等提供综合的网络应用环境。文章就校园网总体建设规划、构筑安全网络平台和校园网功能实现三方面进行了简要介绍。     

浅析VPN在企业移动办公和远程接入中的应用

迅速发展的广域网技术使公网带宽成倍增长,同时又为企业VPN网络提供了广阔的发展空间。VPN技术已逐渐成为企业网安全建设的必要选择。本文针对市场应用的发展需求,介绍了企业移动办公VPN应用和NAT情况下的VPN应用方案,及其采用硬件加速VPN处理的重要性。     

VPN客户端在Windows2000下的实现

简要介绍了IPSec协议体系结构以及在Windows平台下利用NDIS驱动程序接口技术开发基于IPSec协议的VPN客户端软件的方法后，利用流程图阐述了内核模块输入和输出处理的过程以及应用模块的实现。这种借鉴有线网络中的VPN技术和Windows环境编程技术为安全移动办公提供了一种新思路。     

基于IP—VPN的协同设计网络安全问题

异地协同设计与制造技术作为敏捷制造的重要方法和手段，已经成为制造业研究的热点。介绍了IP－VPN的基本概念和关键技术，提出了一个基于IP－VPN的实用协同设计网络模型，而异地协同设计是典型的多用户参与的多任务系统，用户之间存在大量的协同过程，因此网络平台的安全性是协同设计实施的关键问题，对基于IP－VPN的协同设计网络的安全性问题进行了研究，得出了通过采用数据加密、用户认证和基于角色的多层强制访问控制等技术可以构建一个经济、实用、安全的协同设计网络平台的结论。     

三基于企业网的VPN应用方案

分析了虚拟专用网技术的原理,针对企业网实际运行中出现的问题,提出了一种基于企业网的VPN应用方案,将VPN技术应用于基于公共互联网构架的企业网,较好的解决了企业网多办公地点、远程访问、远程管理等问题.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the