高频预提升和补偿在双绞线视频传输中的运用

在监控系统中用双绞线传输视频信号时，高频往往跌落很多。该文讨论一种预提升和补偿的办法，对不同长度的双绞线在传输高频信号时进行不同的补偿，使输出的视频图像信号得到很好的补偿效果，再加上驱动器和接收器，使用双绞线来传视频图像信号的长度可以达到１ｋｍ以上。     

基于宽带接入网技术的探讨

本文简述了宽带接入网技术。如基于双绞线传输的接入网技术，基于同轴电缆传输的接入网技术，基于光传输的接入网技术和基于无线传输的接入网技术，对几种接入网技术进行了比较。     

常见视频干扰现象分析

视频监控信号传输的传统方式视频基带传输。所谓的视频基带传输是指视频信号不经过频率变换等任何处理由图像摄取端通过同轴电缆直接传输到监视端的传输方式,图像在传输时直接利用同轴     

光纤雷达传输系统试验成功

为了开发光纤的应用,了解光纤传输雷达信号的特点,我院通信研究所与720厂设计所共同进行了光纤雷达传输系统的试验,经过不到半年时间的努力,整个系统的试验工作已于最近完成。试验系统是用一根长度为1km、衰耗为7dB的光缆代替原有的四根100m同轴电缆,把796型导航雷达与带有计算机终端的616终端显示相连,传送796雷达送出的视频信号、触发脉冲、方位增量,正北信号。在终端显示器上动目标清楚,计算机录取正确,传输效果不低于原来的同轴电缆。试验表明,光纤是传输雷达信号的一种良好介质,与同轴电缆相比,不仅容量大、损耗小,而且具有较强的抗干扰、抗辐射能力,对雷达通信具有重要意义。此外,雷达具有多种信     

面向广电有线网络的EPON+EOC技术方案

EPON+EOC技术利用光纤的远距离传输和EOC的高性能同轴电缆接入为广电有线网络提供一种安全可靠、性能优越的组网方式,可提供高速上网、高清互动点播、语音电话等高质量多业务宽带接入服务。该文从组网方式、EPON传输技术、EOC接入技术、小区网改案例等方面对EPON+EOC技术方案进行介绍。     

一种HFC双向传输网的设计

光纤同轴电缆混合（HFC）网络传输技术是目前世界上公认的一种较好的宽带输入方式,是信息高速公路最后1km宽带接入网的良好解决方案,是有线电视网的基础。以某小区为设计实体,详尽阐述了该小区的HFC双向传输网设计的方案。     

智能住宅小区能耗自动检测计量收费管理系统的设计与开发

随着住宅小区智能化水平的提高,能耗检测、计量和收费系统的智能化建设将显得越来越重要.本文结合一个智能小区能耗自动检测计量收费系统的设计与开发,介绍了一个完整的系统实例.该系统在检测、通讯和收费管理方面具有许多新的特点,与国内同类系统相比具有一定的先进性[1].     

用双绞线长距离(1 km)传输视频信号的驱动器和接收器的研制

在监控系统中常用双绞线来传图像信号,但是往往信号跌落很多．本文讨论了长距离在双绞线上传输视频信号用的驱动和接收,利用运算放大器ＥＬ１５０１ 和ＥＬ２２８０ 制作的长线驱动器和用ＥＬ２１４２ 和ＡＤ８１８ 视频运算放大器制作的接收器达到了很好的效果,图像清晰稳定,传送测试信号时效果也很好     

浅谈光纤局域网的组建与维护

随着信息技术的发展,光纤作为网络传输介质,具有许多双绞线和同轴电缆无法比拟的优点,已开始被越来越多的单位及个人所接受.面对光纤局域网组建与维护过程中的常见问题,本文通过分析光纤局域网的类型,针对网络组建与维护的关键技术进行探讨,以期在最大程度上保障网络传输的畅通性和安全性,同时降低网络维护成本.     

基于光载射频通信技术的业务终端在智能小区中的应用

作者在光载射频通信技术ROF传输系统的基础上,结合智能小区在多种新型业务方面的需求,对ROF技术在智能小区的系统架构和传输链路中的应用,以及基于ROF技术的多种新型业务终端在智能小区中的实现进行研究.     

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.