共查询到20条相似文献，搜索用时 109 毫秒
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李涛 《成都信息工程学院学报》2005,20(5):582-586
自动重发清求（ARQ）是高速无线网络最常用的有效差错控制方法。SR-ARQ和GBN-ARO传统差错控制方案已不适应高速无线需要，PRIME ARQ和SRPB ARQ改进方案优化了确认开销和延迟，数据吞吐量等同于SR-ARQ，但算法简单容易实现。SRPB ARQ更因为精密的没计使其能在多种无线信道中达到最大数据吞吐量，被应用到HiperLAN／2系统中。描述、分析和比较了以上差错控制方案的特征和性能。 相似文献
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陆斌 《成都信息工程学院学报》1989,(3)
混合差错控制(HEC)是数据传输系统中一种有效的差错控制方法,本文介绍了一种用计算机软件实现混合ARQ的方法,并讨论了混合ARQ系统在VHF信道上的性能。 相似文献
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介绍了链路层用于差错控制的常用技术－－前向纠错编码（FEC）和自动重传请求（ARQ）结合的技术，即混合ARQ。主要介绍HARQ的3种基本类型（编码方案）和ARQ的3个标准重传协议，最后简要给出了3GPP HARQ的两种应用方式。 相似文献
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陕西柞水东甘沟金矿是一个构造角砾岩型氧化金矿床,氧化带深约２００ ｍ ,地表延长达４ ０００ ｍ 。前人对其进行过少量普查和开发（ 全泥氰化）工作。笔者在充分调查研究的基础上,提出了一个科学、合理、可行的详查方案,并对该方案进行了工作量和经费预算。 相似文献
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根据蚀变破碎带型贵金属及多金属矿床多存在高极化的金属硫化物这一特性，利用常规的激电测井及井中激电法，采用１～２ｍ小极距，配合５～１０ｍ大极距梯度测井，井中地—井方式，井口零方位和γ≠０的主、反两方位。通过对蚀变破碎带上不同装置的激电测井曲线特征的讨论，提出了利用常规激电测井对蚀变破碎带进行划分的方案 相似文献
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吴序运 《广东海洋大学学报》1995,(1)
１９９０年在潮上带３ｍ的大梅沙养殖场选２８口共１０９００２．４ｍ２虾池进行斑节对虾高产养殖试验。采用提水式供水、虾池小型化、投苗高密度，配备增氧机，精心管养。试验结果获得总产６９５７７．３ｋｇ，平均０．６４ｋｇ／ｍ２，最高１．０１ｋｇ／ｍ２。潮上带提水式高密度精养斑节对虾，具备条件是确实可行的。 相似文献
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林东年 《广东海洋大学学报》1995,(1)
为了提高渔业生产力，拓展外海作业渔场，设计了外海快速高产拖网（主尺度：１２８．００ｍ×８７．０１ｍ（４５．１２ｍ））。该拖网采取短网盖、短网袖、长网身和增加浮沉力的措施来减少拖网阻力，加快拖速，从而提高拖网的捕鱼能力。１９８８年１２月至１９８９年１１月在博贺港外海进行了对比捕鱼试验，１９９０年６月在东海水产研究所水槽进行了网模试验，均获得良好结果，并在茂名市渔港进行了推广应用，推广面达８７．５％。 相似文献
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奥斯特 《地球科学与环境学报》1994,(2)
现代气候条件下，秦岭中部（３３°５８＇Ｎ／１０７°４５＇Ｅ）３４００ｍ以上存在一具有冰缘地貌特征和冰川作用的高山草甸环境。冰冻泥流斜坡、千奇百怪的砾石和无植被覆盖的冰冻泥流、各种形式的冰阶和冰坎以及石环和石多边形等，组成了目前冰缘环境的地貌特征。在３４００ｍ以上发现了高山永久性冻土。通过冰蚀漏斗和冰融四地，证明在２９００～３３００ｍ之间秦岭中部存在一晚更新世时期的冰融地区。根据古冰斗和冰碛的地貌形态调查及形态测量分析，可得出如下假设：在拔仙台、酉跑马梁附近当时存在一个晚更新世时期的小冰盖，冰盖边缘派生了５个小的外流冰舌。在拔仙台附近的沟谷里一些冰碛地貌存在于２５００ｍ以上。笔者根据调查结果，划分了两个晚更新世时期的冰期，即太白Ⅰ和太白Ⅱ冰期。在这两个冰期之间，估计存在一间冰期。晚更新世３２５０～３３００ｍ的冰川雪线高度是根据太白Ⅰ冰期冰碛位置得出的。同目前所推测的现代冰川雪线位置相比，形成的雪线下降大约在１０００～１３００ｍ之间，没有观察到全新世冰川遗迹。 相似文献
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报导了１９９４～１９９５年春在湛江港进行浒苔、礁膜的生态调查。每月在湛江港的特呈岛东北角及南三岛湖村两个海区插竹签观察幼苗附着及藻体的消长情况。发现４月份大部份藻体成熟，并放散孢子。５月份藻体逐渐消失。６月底竹签上出现极小的幼苗，７、８、９三个月幼苗生长缓慢，１０月份幼苗生长加快，１１月份藻体长达３～５ｃｍ，１２、１、２月份生长最茂盛。１１月份又在两海区各安放一个１００×１００ｃｍ的维尼纶网片，１２月份附着一定数量的幼苗，生长迅速．２月份长达１０ｃｍ以上。３月份收获，特呈岛海区为１１６ｇ／ｍ２干品，南三岛海区为１２５ｇ／ｍ２干品。初步结论：采天然苗生产应该在１１月份进行。 相似文献
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Based on the hydrographic data in austral summer during the 22nd Antarctic Expedition of China(2005/2006),some features can be found about the northern margin of Emery ice shelf as follows.The heat content in the surface layer(0-50 m) at the eastern end and the western end of the ice-shelf margin is much higher than that at the middle.The upper mixing-layer depth and the seasonal thermocline depth at the middle of the ice-shelf northern margin are much shallower than those at the both ends.However there is much less difference between the middle and the ends in the bottom layer.The remote sensing photos show that the inhomogeneity in the surface-layer water is closely related to the spatial distribution of the floes and polynia in the area. 相似文献
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Phylogenetic analysis based on 16S rDNA of 8 strains of cultivable bacteria isolated from Arctic sea-ice was studied.The results showed that strain BJ1 belonged to genus Planococcus,which was a genus of low mole percent G C gram-positive bacteria;strain BJ6 belonged to genus Burkholderia of β-proteobacteria and the rest 6 strain all belonged to γ-proteobacteria,of which strain BJ8 was a species of Pseudoalteromonas,strain BJ2-BJ5 and BJ7 were members of genus Psychrobacter.Phylogenetic analysis also indicated that bacteria of genus Psychrobacter of the isolates formed a relatively independent phylogenetic cluster in comparison with other bacteria belonged to genus Psychrobacter. 相似文献
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《极地研究(英文版)》2014,(3)
正1 Aims and Scope Advances in Polar Science(APS)is an international,peer-reviewed journal jointly sponsored by the Polar Research Institute of China and the Chinese Arctic and Antarctic Administration.APS is a comprchensive academic journal dedicated to presentation of multi-disciplinary achievements in Arctic and Antarctic expeditions and research.Its primary purpose is to publish achievements in fundamental research,applied 相似文献
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《山地科学学报》2014,(4):I0004-I0009
<正>AIMS AND SCOPE(Editorial Policy)The Journal of Mountain Science(JMS)is devoted to mountains and their surrounding lowlands-ecoregions of particular global importance,with a particular emphasis on the important highlands/mountains in the world,such as the Tibetan Plateau,the Himalayas,the Alps,the Andes,the Rockies and many other mountain ranges of our planet. 相似文献
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《山地科学学报》2014,(4)
<正>The Journal of Mountain Science(JMS),founded in2004,is an international English-language journal on mountain sciences.JMS is supervised by the Chinese Academy of Sciences(CAS),sponsored by the Chengdu Institute of Mountain Hazards and Environment,CAS,published by Science Press China,and distributed by Springer exclusively throughout the world(excluding Mainland China).The JMS is published bimonthly,fulltexted in SpringerLink and CNKI,indexed/abstracted by 相似文献
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References： 《极地研究(英文版)》2007,18(1):73-83
Using the NCEP/NCAR reanalysis monthly 500 hPa height data on a 2.5 latitude-longitude grid and 1°×1° sea ice data,the polar vortex area,intensity index and arctic sea ice area index are calculated respectively,and the meridional distribution,period variation and the abrupts in the long range trend are analyzed to study their relationship.The results show that the meridional distribution of sea ice and polar vortex h-ave distinctive difference,the relative positions of them are different in the eastern and western hemispheres,and exept they have periods of 4 months,quasi half year,quasi year,4-5 years and 10 years commonly,and each of them has its own respective variation as well.The sea ice area is decreasing apparently since 1980's,so is the polar vortex area,but their abrupt changge time are different totally.The area of sea ice and polar vortex has prominent positive correlation,but the relationship of sea ice intensity,polar vortex intensity,polar vortex area is complicated. 相似文献
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《中国海洋大学学报(英文版)》2014,(3):I0001-I0001
<正>The Journal of Ocean University of China(Oceanic and Coastal Sea Research)is a comprehensive academic quarterly sponsored by the Ocean University of China,published one volume per year.This journal is devoted to the publication of the theoretical and applied research 相似文献