共查询到20条相似文献，搜索用时 62 毫秒
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夏桥 《广东海洋大学学报》1980,(1):72-79
新型的劳兰A接收机设置了一系列的自动控制电路，不但使操作更简单，并且保证了测量的速度和精度，减少了测量精度对操作人员技巧的依赖。自动控制系统包括自动搜索，自动同步、自动跟踪以及自动增益控制等。 相似文献
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微波脉冲调制及其功率测量电路的设计 总被引：1，自引：0，他引：1
脉冲调制电路采用HMC232LP4开关元件,由74HC04构成的控制电路产生互补开关驱动电压来控制HMC232LP4的导通状态,用开关切换的方式实现了输入连续载波的脉冲调制.功率测量电路中.AD8317对数解调放大器将输入微波信号功率转化为电压输出,且输出电压正比于输入功率,实现微波信号功率的测量.通过实验测试.微波脉冲调制器实现了快速切换的功能,隔离度达到了55dB,信号动态范围70dB;功率测量电路线性输出动态范围达50dB,功率测量灵敏度为-55dBm,频率特性稳定,输入输出满足某种关系,能方便地完成微波功率的测量. 相似文献
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一种新型的多界面液位传感器设计 总被引：1，自引：0，他引：1
设计一种基于ATmegal 6芯片作为微控制器的电容测量电路,适应多种电容式传感器测量的需求。利用正弦波实现了小电容量的相位检测,根据电路参数计算电容容值,还可以根据具体情况调整电路参数,电路适用性广。理论分析和仿真证明,这种多界面的智能液位传感器具有优良的性能。 相似文献
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悬索桥主缆施工控制与监测 总被引：1，自引：0，他引：1
分析悬索桥主缆施工过程中测量数据的影响因素及误差来源，介绍测量方法的应对调整方案。主缆线形基准索股测量无法使用几何水准，采取先进高精度测量全站仪器、只能单向三角测量，一台全站仪器进行单向三角测量如果出现粗差无法校对，同时测量的基准索股对温度变化、风力的大小、塔位的偏移等因素十分敏感，因此对测量方案进行调整，选择在无风或风力很小、温度稳定的夜间进行，用两台高精度的自动跟踪全站仪同步单向三角测量，使得测量任务能在短时间完成，满足悬索桥主缆施工控制精度要求。 相似文献
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王荣辉 《广东海洋大学学报》1997,(1)
阐述了以MCS－8098单片机为处理机实现STD工控总线的方法，给出了8098单片机的最小系统配置，选择不同的标准功能模板及少量特殊电路，就可以构成不同的实时控制系统。 相似文献
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王荣辉 《广东海洋大学学报》1997,17(1):56-60
阐述了以ＭＣＳ－８０９８单片机为处理机实现ＳＴＤ工控总线的方法，给出了８０９８单片机的最小系统配置，选择不同的标准功能模板及少量特殊电路，就可以构成不同的实时控制系统。 相似文献
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夏桥 《广东海洋大学学报》1980,(1)
新型的劳兰A接收机设置了一系列的自动控制电路,不但使操作更简单,並且保证了测量的速度和精度,减少了测量精度对操作人员技巧的依赖。自动控制系统包括自动搜索,自动同步、自动跟踪以及自动增益控制等。本文分别介绍自动控制 相似文献
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在传统激光测距仪设计思路的基础上重点论述了激光光源选择与人眼安全、光电探测器选择与接收前置放大电路的设计、光学系统设计以及噪声分析等方面的问题。 相似文献
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TCM-3型测温仪采用Pt100铂电阻作为温度传感元件,结合铂电阻稳定性和重复性好、线性度高的特点及实际应用环境的限制,通过后续电路的设计使TCM-3型测温仪达到了要求的测量精度,并从理论上进行误差分析,检验了其测量精度的可靠性. 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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The ability of cell to modulate the fluidity of plasma membrane was crucial to the survival of microorganism at low temperature. Plasma membrane proteins, fatty acids and carotenoids profiles of Antarctic psychrophilc yeast Rhodotorula sp. NJ298 were investigated at -3 ℃, 0 ℃ and 8 ℃. The results showed that plasma membrane protein content was greater at -3 ℃ than that at 8 ℃, and a unique membrane polypeptide composition with an apparent molecular mass of 94.7 kDa was newly synthesized with SDS-PAGE analysis; GC analysis showed that the main changes of fatty acids were the percentage of unsaturated fatty acids (C18∶ 1 and C18∶ 2) and shorter chain saturated fatty acid (C10∶ 0) increased along with the decrease of the culture temperature from 8 ℃ to -3 ℃; HPLC analysis indicated that astaxanthin was the major functional carotenoids of the plasma membrane, percentage of which increased from 54.6±1.5% at 8 ℃ to 81.9±2.1% at -3 ℃. However the fluidity of plasma membrane which was determined by measuring fluorescence anisotropy was similar at -3 ℃, 0 ℃ and 8 ℃. Hence these changes in plasma membrane's characteristics were involved in the cellular cold-adaptation by which NJ298 could maintain normal plasma membrane fluidity at near-freezing temperature. 相似文献