海底光缆故障路由探测用拖曳电缆的研制

海底光缆损坏事故发生时,为及时修复故障,需准确探测到损坏部位。拖曳电缆是水下光缆维护系统中水下金属物体探测设备、海底光缆定位设备、拖曳浮标等设备的关键元件．可有效确保探测头的电力供应和探测信号的传输使用。拖曳电缆用于海水下轻型作业物体的拖曳和信号传输,具有良好的绝缘电气性能,优良的耐环境适应性。能够阻水、能漂浮;优良的机械性能。抗拉强度大,能够在小弯曲半径下弯曲上百次。     

连接器对拖曳线列阵水动力和姿态仿真分析

拖曳线列阵在军事及民用领域有着广泛的应用,其水动力学和姿态控制是各种拖曳线列阵系统设计的关键。基于Albow和Schechter方法,建立了拖缆——子阵——连接器的联合水动力模型,并采用有限差分方法和牛顿迭代法求解。以某拖曳线列阵为研究对象,研究分析了不同工况的拖曳深度、拖曳力和俯仰角参数。研究结果表明：随着拖曳速度的变化,拖曳线列阵深度和拖曳力变化很大;不同分段长度的拖曳线列阵的姿态在不同拖曳力下变化不大。该模型可对各种拖缆及拖曳线列阵的拖曳力及水下姿态等做出预判,为绞车及整个拖曳线列阵系统等整体设计提供支撑。     

捕鱼装置拖曳造成的海底光缆损伤中张力和扭矩的影响（二）

在之前对捕鱼装置拖曳造成的海底光缆损伤的研究中，美国Tyco通信公司的研究人员得出的结论是：摸拟因捕鱼装置拖曳造成的不同惑生张力和力矩的可控负荷实际上减轻了拖曳对光缆造成的损伤。目前，通过制备较长的铠装光缆试样及仿制捕鱼装置以便模拟光缆被捕鱼装置钩住并随其一起移动的情况，公司的研究人员正在继续研究捕鱼装置拖曳对光缆造成的损伤。光缆的张力和力矩不像以前一样被对称控制，但它们会因受到捕鱼装置拖曳而在光缆试样中自然产生。对光缆损伤的评定不仅要通过光缆物理性能的变化，还要通过光缆中和高压试验中光纤的衰减变化来表征。这为受损光缆及其受到拖曳袭击后的耐久性提供了一种更实际的评定方法。在实际的光缆拖曳模拟过程中，研究人员研究了张力和力矩的协同效应，并与之前的研究进行了比较。研究的试样不仅有铠装光缆，还包括特殊用途光缆。根据光缆损伤和光纤性能的结果，研究人员发现了拖曳严重程度与光缆损伤情况之间的相互关系，并获得了应对捕鱼装置拖曳的更好的光缆设计。     

水下电视摄像装置的选择

水下电视摄像装置的选择中船总７５０试验场杨化俊近年来，随着半导体技术、微光技术和数字技术的高速发展，作为应用电视一分支的水下电视摄像设备取得了非常迅速的发展，在海洋研究与开发、海洋地质研究、水下工程建设、水下石油钻探勘察、船舶维修和水下打捞方面的应用...     

机械天线通信技术研究现状

与电调天线相较,机械天线具有全新的电气参数定义,其信号的频率只与携带辐射场的物质机械运动的频率相关,因而克服了电调天线信号频率对天线尺寸的依赖,可以用小型设备产生低频信号,应用于水下和地下便携式低频通信设备的设计中。从辐射场特性、辐射场发生装置以及信息加载三个方面介绍了机械天线通信系统的研究现状,总结了机械天线发展需要重点解决的技术难点。     

小型锅炉控制系统的设计

本文就小型锅炉系统运行情况分析，介绍了一种适用小型锅炉装置的自控系统的设计及应用情况。     

基于水下拖缆电磁信道的信号传输方法研究

针对目前水下拖曳系统有线通信成本高,易受外力损坏等缺点,提出一种基于水下裸露拖曳钢缆的电磁信号传输方法.利用等效传输线理论,建立了传输信道的电路模型和传递函数.分析了水的电导率、信号发射频率、拖缆入水长度对接收信号电压的影响,得到传输距离与信道通频带的关系;分析了水下拖缆长度的动态变化对信道时变特性的影响,选择FSK为...     

捕鱼装置拖曳造成的海底光缆损伤中张力和扭矩的影响（一）

捕鱼装置等造成的外部损伤对海底通信光缆极其有害，会导致通信中断和潜在的资金损失。通常所说的损伤是指压扁或切断光缆。海底光缆的设计采用铠装钢丝来保护光缆，使其免受由捕鱼装置拖曳和摩擦造成的潜在损伤或其它外部袭击。通常这些起铠装作用的钢丝呈螺旋状卷绕在缆芯外，但这种螺旋形状并不是一成不变的。当光缆受到捕鱼装置的侵袭时，对铠装光缆的损伤不能仅用简单的压扁来表征。由于铠装钢丝的螺旋形状随张力和扭矩而变化，保护作用在受到捕鱼装置侵袭的过程中也会不断变化。通常在受力状态下敷设铠装光缆。因此，在受到捕鱼装置等外部元件的碰撞时张力迅速增大。另外，在捕鱼装置拖曳的过程中光缆会产生张力和扭矩。这两个因素有助于增强铠装光缆抗捕鱼装置接触损伤的能力。为了了解拖曳张力的影响以及光缆损伤机理中产生的与光缆有关的扭矩，美国Tyco通信公司光缆开发部设计并进行了一系列的研究和试验。结果将用于风险评定以及进一步增强铠装层对光缆的保护能力。     

水下目标信号特征提取与采集研究

提出了基于子波变换的辐射噪声特征提取方法，据此获得了水下目标的有效频率分布范围，为水下目标信号采集器的设计确定了频率范围，同时介绍了水下目标信号采集器的硬件结构、实现方法和实验结果。     

一种海洋可控源电磁发射拖体姿态及海洋环境参数在线监测的方法

近年,海洋可控源电磁法(Controlled-Source Electromagnetic Method,CSEM)在海底油气资源探测中有了更进一步的应用,其中,深海拖曳式CSEM的应用更为广泛。文章把CDTV(声速剖面仪和温盐深仪)和离底高度计安装到可控源拖体上,开发了基于RS232串口数据传输的实时监测程序,进行设备数据采集,通过拖缆把参数上传,在甲板上对水下拖体姿态、离底高度和海洋环境参数进行实时监测。     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks     

Call for Papers—Feature Topic,Vol.12,No.7,2015

正Information Centric Networking Information-Centric Networking(ICN) is an emerging direction in Future Internet architecture research,gaining significant tractions among academia and industry.Aiming to replace the conventional host-to-host communication model by a data-centric model,ICN treats data content as the first     

JOURNAL OF ELECTRONICS(CHINA)

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NEXT GENERATION WIRELESS NETWORKS–ESPECIALLY THE USE OF MILLI-MICROWAVE BANDS

The global bandwidth shortage of wireless communications has motivated the exploration of the naillimeter wave （ram-wave） frequency spectrum for the next generation wireless communications. Recent advances in RF CMOS technology and high speed baseband signal processing technologies have enabled tile extensive research and development of turn-wave wireless communications. The multi gigabit per second data rate of ram-wave system will lead to applications in many important scenarios, such as WPAN, WLAN,back-haul for cellular system. And the frequency bands include 28 GHz, 38 GHz, 45GHz, 60GHz, E-BAND and even beyond 100 GHz. The propagation and the imitation of the RF circuits design in these frequency bands make the directional antennas be inevitable for mm-wave communications.