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采用中规模集成电路设计同步计数器，是中规模电路的一种应用，它省去了小规模集成电路设计中过于繁琐步骤。使得同步计数器的设计变得简单、方便、实用。而且还有省时省力、提高效率的优点，有一定的参考价值。 相似文献
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何震 《广东海洋大学学报》1989,(Z1)
本文是关于采用三个TTL D触发器和六个译码器来组成扭形计数器的设计。但是在讨论扭环形计数器之前,要用2个TTL D触发器来组成一个异步计数器,这样处理可以避免在译码时产生的竞争冒险。 相似文献
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周珏 《成都信息工程学院学报》1998,(3)
针对用“直接反馈法”不能实现移位寄存器型计数器的自启动,提出了一种简单、实用的措施,即在原电路的基础上仅对反馈逻辑关系作修改,使电路变成能自启动的移位寄存器型计数器。 相似文献
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研究矢量匹配、多尺度海洋数据集成、同步更新技术和更新冲突处理规则与方法等关键技术,设计浙江省海洋基础空间要素数据库更新系统,实现了岛(礁)、滩涂、水下地形三个独立的海洋数据库与海洋基础库的同步更新,提高了海洋基础空间数据的应用服务能力。 相似文献
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地震监测SAR卫星需求分析与轨道设计 总被引：1，自引：1，他引：0
通过对SAR卫星在地震监测任务中的需求分析。确定者这种卫星应该具备干涉和大视角两种工作模式。并利用太阳同步准回归轨道设计方法初步进行了地震监测SAR卫星的轨道设计。 相似文献
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针对空间大地测量及航天技术的需求．分析了提高SLR数据精度和数据量的技术和方法,讨论了在原有流动卫星激光测距仪TROS-Ⅰ的基础上对激光器、计数器以及控制设备等关键部分进行改造的可行性,并提出了设计方案。 相似文献
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监测网的精度是通过它的网形和观测方案来实现,因而研究设计合理的观测网形和观测方案有很重要的意义。针对以往一、二类设计分开单独进行解算不可能求得整体上最优,提出了非线性一、二类同步设计的新方法。该方法将一、二类设计的决策变量在一个模型中解算,可获得整体最优解。 相似文献
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基于纠缠光子对二阶相关函数的时间特性分析,设计时钟同步测量方案,并考虑传播过程中色散效应及衰减等对精度的影响。该方案可提供均值1 ns、精度0.01 ns的同步信息。利用该方案获得观测数据,结合顾及哈达玛方差的抗差卡尔曼方法估计出卫星钟差模型系数,进行钟差预测。仿真表明,该方案预测精度与IGS预报星历产品精度相当,且钟差初始值更精确。 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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Livestock behaviour in the Pyrenees includes free grazing and a long resting period that provokes the accumulation of dung and urine in some places,so-called camping areas. The aims of this study were （i） to analyze any change in floral composition,and in nutritional and chemical contents of plants in a livestock camping area; and （ii） to relate the floral composition with soil chemical properties. In a linear transect,five sampling zones were established,from the centre of the camping area to the surrounding Nardus stricta-dominant pasture. The above ground plant biomass and the topsoil were sampled in each zone with 6 replicates per zone. Plant species were classified and weighed to calculate above ground biomass,nutritional and chemical contents,and Shannon diversity and evenness indices. Additionally,soils were sampled in two periods,at the beginning and at the end of grazing period. Soil available nutrients （nitrate,ammonium,phosphorus,potassium,calcium and magnesium）,total nitrogen,organic carbon and pH were measured.
Plant chemical contents （protein,lignin and others） were significantly related to the proportions of grasses,legumes and other plants; so,the protein content is positively correlated with legumes plant biomass while lignin content is negatively correlated with grasses. Both plant and soil nutrients increased linearly towards the centre of the camping area. However,the relationship among plant species richness,diversity and evenness relative to its position along the studied transect was bell-shaped. From the outskirts to the centre of the camping area,plants with low nutrient demand were progressively replaced by those with medium and high nutrients demand and by pioneers.
Nardus stricta-dominant pasture has low plant diversity and plant nutrient content as well as a poor soil nutrient availability. The presence of the camping area introduced patches with more soil nutrients and new species in the large spatial scale. However at a small spatial scale,the strong soil nutrien 相似文献
Plant chemical contents （protein,lignin and others） were significantly related to the proportions of grasses,legumes and other plants; so,the protein content is positively correlated with legumes plant biomass while lignin content is negatively correlated with grasses. Both plant and soil nutrients increased linearly towards the centre of the camping area. However,the relationship among plant species richness,diversity and evenness relative to its position along the studied transect was bell-shaped. From the outskirts to the centre of the camping area,plants with low nutrient demand were progressively replaced by those with medium and high nutrients demand and by pioneers.
Nardus stricta-dominant pasture has low plant diversity and plant nutrient content as well as a poor soil nutrient availability. The presence of the camping area introduced patches with more soil nutrients and new species in the large spatial scale. However at a small spatial scale,the strong soil nutrien 相似文献
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文章概略介绍了利用卫星进行定位的原理 ;由卫星信号传播、信号接收和SA政策等引起的理论误差 ;给出了多种快速、高精度定位的工作模式和观测点选择的原则 ;列出了将WGS - 84坐标转换为我国坐标的公式及解算参数的具体方法 ,供读者在GPS工作中参考。 相似文献