多出口下的校园网NAT应用探析

为了在经济的基础上提高校园网的出口带宽和安全性，在策略路由的基础上运用NAT技术实现了双出口接入互联网。首先介绍了我校校园网的基本情况，说明了双出口接入互联网的必要性，然后提出了所面临的问题以及解决问题的思路，最后详细叙述了用iptables实现NAT功能的全过程。     

校园网多ISP接入及优化方案

由于高校校园网接入CERNET的出口带宽低,造成校园网用户访问INTERLNET的速度慢,而且费用昂贵。所以大部分高校都接入其他ISP的带宽解决出口问题,在接入其他ISP带宽的时候采用NAT技术、策略路由均衡各个ISP的带宽,同时采用限制线程数、限制带宽等技术保证高校校园网各个用户合理利用带宽。     

多出口环境下校园网用户访问互联网的策略研究

针对接入网络之间存在带宽瓶颈问题,阐述了在校园网多出口环境下,采用策略路由、网络地址转换(即NAT)和智能DNS等技术,有效提高了校园网用户访问因特网的速度。     

基于VRRP和NAT多出口校园网可靠性仿真试验设计

本文介绍了结合VRRP和NAT保证多出口校园网可靠性的设计方案.网络正常工作时实现网关冗余和负载均衡,网络出现故障时,备用路由器负责数据包转发,从而保证校园网用户在访问互联网资源时不受任何影响.     

基于策略域名解析和硬件防火墙的校园网双出口解决方案

由于CERNET和CHINANET之间存在带宽瓶颈等问题,很多高校都采用同时接入教育网（CERNET）和电信网（CHINANET）的双出口方案,以提高校园网对公网的访问速度。本文结合网络规划、设计和实施中的亲身实践,分析研究了该技术的主要特征,介绍了一种在不增加校园网软硬件基础上的基于策略域名解析和硬件防火墙的校园网双出口解决方案,提出了具体的实现方案,解决了目前许多高校因采用双出口方式带来的一系列问题,优化了网络的配置。     

NAT技术在校园网中的应用

介绍了NAT技术在校园网多链路接入、VOD点播负载均衡及网络安全等方面的具体实现方法，同时指出了NAT技术的优缺点。     

校园网双出口的设计与实现

本文通过分析当今高校校园网的现状,原有单一的CERNET出口已不能满足,有必要进一步扩大带宽。提出了一个校园网双出口解决方案,通过当地网络服务提供商（ISP）开辟第二出口连入Internet。详细阐述了其解决方案和实现过程,方案使校园网同时实现了教育网和公网的高速接入,并在一定程度上提高了校园网的安全性。     

双出口校园网的设计与实现

分析当今高校校园网的现状,提出一个校园网双出口解决方案,详细阐述了其采用策略路由、网络地址转换等关键技术的实现过程.方案使校园网同时实现了教育网和公网的高速接入,并在一定程度上提高了校园网的安全性.     

校园网双(多)出口的基本解决策略和方法

大多数高校的校园网在接入CERNET的同时,又相继接入了中国电信(CHINANET)、网通等公众网。由于各学校的域名地址及校园网内的服务器地址,通常使用的是教育网的IP地址,因而,在校园网存在着双(多)出口的情况下,如何规划和配置网络出口处的设备,提高校园网内的用户对整个互联网的访问速度,以及解决CERNET地址外的用户对校内开放资源的快速访问,是值得分析和探讨的问题。     

基于策略路由和NAT的多出口校园网仿真实验设计

原有一条ISP出口链路已不能满足校园网日常应用需求,文章提出了增加校园网ISP出口链路,并在校园网出口路由器上应用策略路由和NAT技术的解决方案,不仅给出了详细的配置过程,而且还模拟了在出口链路发生故障情况下,数据包的路由过程.测试证明该方案实现了多出口校园网流量负载均衡和链路备份,满足了校园网日常应用需求.     

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

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.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

A computer generator for randomly layered structures

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

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。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.