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Optical investigations of Estonian and Finnish lakes 总被引：2，自引：0，他引：2
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为了实现封堵器海洋工作环境中的无线遥控动作,封堵器在海底工作中采用了水声通信技术.文章首先介绍了水声通信系统的整体设计.在前期工作中,从影响水声通信的因素出发,对水声通讯频率的选择及水声换能器的选型进行了研究,确定了水声通讯的载波频率.在此基础上提出了基于单片机的水声Modem的制作方案,设计了单片机系统电路.并对单片... 相似文献
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描述了能量效率(energy efficiency)和在水下无线通信网络中最优化的数据包结构特点.由于水下传感器节点的电池能量受到限制,能效就成为数据包结构设计中最先考虑的环节.ns2是一种面向对象的,由离散事件驱动的,运行在UNIX操作系统中的网络模拟器,本文利用模拟器软件得到水声通信能效图表,从而对最优的数据包的选择进行了研究. 相似文献
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《Journal of Modern Optics》2012,59(20):1998-2007
ABSTRACTWe report on experiments where non-uniformly correlated (NUC), Gaussian Schell (GSM) and Multi-Gaussian Schell (MGSM) model spatially partially coherent laser beams were propagated underwater. Two scenarios were explored: still water and mechanically agitated water. The main objective of our study was the experimental comparison of the scintillation performance among beams with different correlation functions. The results show generally increased absolute values of scintillation index for NUC beams as compared with GSM and MGSM beams. We hypothesized that this effect is related to the method of NUC beams generation. It should be noted, that the presented results document only the given experimental scenarios and show the relative comparison between GSM, MGSM and NUC beams with Gaussian used as a turbulence level benchmark. Further investigation is necessary to broaden the scope of our explorations of the propagation of uniformly correlated spatially partially coherent as well as non-uniformly correlated beam classes. 相似文献
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《Journal of Modern Optics》2012,59(19):1871-1875
ABSTRACTThe effect of the anisotropy on the bit-error-rate (BER) performance of subcarrier intensity modulated (SIM) binary phase shift keying (BPSK) optical wireless communication (OWC) links operating in weakly turbulent underwater channels is examined. BER variations versus the anisotropic factor are examined when the bandwidth, photodetector responsivity, load resistor and the underwater turbulence parameters are varied. As anisotropy in the underwater channel becomes larger, SIM BPSK OWC links have better BER performance at any link and turbulence parameter. 相似文献
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In order to improve the explosion characteristics of emulsion explosives, titanium hydride was added to emulsion explosives to produce a new type of hydrogen storage emulsion explosives. Charges with different contents of titanium hydride were evaluated through underwater explosion experiments and detonation velocity tests. The tests on underwater explosion and detonation velocity reveal that compared to pure emulsion explosives, the detonation parameters of emulsion explosives containing titanium hydride showed a trend of first increasing and then decreasing. When the mass ratio of titanium hydride in the emulsion explosive is 1 % to 3 %, all detonation parameters have been improved to a certain extent. When the mass ratio of titanium hydride in the emulsion explosive is 3 % to 10 %, only part of the detonation parameters (specific impulse, specific shock energy, specific total energy and volume energy density) has been improved. The maximum increase of specific impulse, specific shock energy, specific total energy and volume energy density of emulsion explosive containing titanium hydride is 7.06 %, 8.95 %, 3.97 % and 8.22 %, respectively. Based on the analysis, it is evident that though powdered TiH2 participates in the detonation reaction process of the emulsion explosive, the majority of TiH2′s energy is released during the secondary reaction occurring after the detonation wave front. Therefore, the detonation performance of emulsion explosives can be effectively improved by adding a certain mass ratio of titanium hydride. 相似文献