纤锌矿CdSe量子椭球的电子结构和光学性质

在有效质量包络函数理论的框架下，经过坐标变化给出了椭球形纤锌矿结构CdSe量子点的哈密顿量并对其电子结构和光学性质进行了计算，给出了电子和空穴能级随椭球横纵比变化的图形并对其做出了解释，对量子椭球发光的偏振性给出了解释，分别讨论了晶格分裂场，温度和短轴半径对偏振度的影响，最后计算了长短轴对能带的影响。     

无线电管理局刘岩副局长：推动无线电管理法制化

2003年，我们在原有基础上进行了无线电频率规划，编写完成了无线电频率规划英文版工作，调整1800兆无线接入频率的容量，从原来5兆扩展到现在的20兆。对全国的台站进行了一次普查，而且对数据库进行了重新跟踪，对集群频率进行了     

CR:一种逆向的关联规则挖掘算法

引入与交易相关的有关概念，对传统关联规则挖掘的概念进行了扩展，并基于交易提出了一种关联规则挖掘算法，该算法从较长的交易入手，试图找出长的频繁项集，再确定它们的子项集，从而避免了组合爆炸问题。该算法对原数据库进行1次扫描，对压缩数据库进行了2次扫描，较Apriori算法减少了扫描次数，提高了挖掘效率。     

玻璃钢的二氧化碳激光碳化实验研究——玻璃钢的激光碳化破…

本文介绍了利用二氧化碳激光器对新型复合材料４５０１Ａ型玻璃钢进行烧蚀实验，测量了烧蚀失重，碳化热和碳化深度，并对玻璃钢的碳化物，烧蚀物进行红外散射谱分析，作为碳化破坏对微波传输影响的直接相关量，我们利用微波矢量网络分析仪对８．２～１２．４ＧＨｚ微波的传输特性进行了测量，得到了透射率，插入相移随能量密度的变化。     

第三层交换技术浅析

第三层交换技术（Ｌａｙｅｒ３Ｓｗｉｔｃｈｉｎｇ）的兴起，对整个网络界产生了极大的影响，它提高网络的性能，对局域网乃于广域网的网络体系结构设计也产生了很大的影响，本文在回顾了交换技术发展过程的基础上，对第三层交换技术的实现要点和技术进行了详细地阐述，在文章的最后，给出了作者对第三层交换技术的未来的一些看法。     

船舶海上超视距无线自定位技术研究

针对卫星拒止环境下，海上船舶及其编队对导航定位性能的最低保障需求，开展了一系列研究。首先分析了线阵综合测角的基本理论，用遗传算法对线阵进行了综合仿真，用谱估计对线阵测角进行了研究；其次对圆阵综合测角进行了理论分析，对圆阵、圆柱阵进行了综合计算和谱估计测角仿真，分析了不同阵元数、信噪比等情况下的测向夹角情况，并对多信号同时测角情况进行了仿真；最后阐述了夹角定位的基本思想，提出了船舶传感器构阵测角的可能形式， 并对定位数据进行了分析及滤波优化。研究结果表明，相关技术对船舶海上导航定位有积极的参考意义。     

履带车横纵摇对雷达天线指向影响的计算分析

建立了履带车横纵摇对雷达天线指向影响的分析模型，推导了一套计算公式，并实现了程式化，给出了一个算例，对产生的误差进行了分析，用CAD三维系统进行了仿真。     

多媒体通信网

文章首先对多媒体通信的应用与服务作了一个概括介绍，接着对多媒体通信的要求，着重于带宽，数据压缩，服务质量以及同步进行了简要分析，最后对数据压缩特别是常用的图像压缩方法和标准以及同步技术作了扼要介绍。     

巧用明线载波技术解决地县长话紧张问题

本文介绍了现有地县长话网的状况，对明线电路进行了分析，提出了利用明线载波技术，增加复用系数，以解决电路紧张的矛盾，对不同线路，如何配置载波设备等也提出了建议。     

微通道式PCR芯片温度的研究

微通道式PCR芯片是对DNA扩增的新方法，通过样品试剂在三个温区间的流动，实现对试剂中特定DNA片段的几何级数扩增。研究了一种新型微通道式PCR芯片，利用有限元技术，对芯片上热区的温度梯度和均匀性进行了计算，对影响PCR反应的三种温度因素作出了定量分析。另外，针对传感器和加热器的外形、放置以及加热区的不均匀化，采取了系列优化措施，计算了薄膜电阻功率和电阻参数，改善了芯片的热特性，提高了其倍增的效率。     

WDM光传送网络中数字包封与前向纠错分析

为适应多种不同格式信号 (如 ATM、SDH、IP等 )透明传送的需要 ,高速 WDM光传送网络采用数字包封技术。按照 RS纠错码编码规则 ,采用相应的编码形式可纠正一定的突发误码。WDM光网络系统的 TDM数字包封采用 RS纠错码编码 FEC应用形式。分析了 TDM数字包封的基本原理及 RS纠错码编码 FEC的纠错性能特性。     

All-optical WDM to TDM transmultiplexer

An all-optical WDM to TDM converter, or transmultiplexer, is described. The transmultiplexer is based on optical frequency conversion by gain compression in semiconductor optical amplifiers. Operation of the transmultiplexer is demonstrated experimentally, and bit error rate measurements are reported     

Calculation of dispersion and nonlinear effect limited maximum TDMand FDM bit rates of transform-limited pulses in single-mode opticalfibers

The dispersion-limited maximum time-division-multiplexed (TDM) bit rates and the optical nonlinear-effect-limited maximum frequency-division multiplexed (FDM) channel numbers in single-mode optical fibers have been calculated for transform-limited optical pulses. The total bit rate attainable with combinations of TDM and FDM on Gaussian-type transform-limited pulses is about 7 Tbt/s in the typical 15 THz wide low-loss region of single-mode fibers at each of 1.3 and 1.5 μm wavelength bands. The maximum total bit rate attainable with dispersion-shifted (DS) fibers in the Er-doped fiber amplifier (EDFA's) gain region of 1525-1565 nm is calculated to be about 2.3 Tbt/s, but reduces to 1.2 to 1.8 Tbt/s depending on fiber length for cases of a uniform TDM bit rate over the entire FDM channels. For DS fibers the four-wave mixing effect is a dominant effect limiting the channel power and the maximum FDM channel number, but for normal single-mode fibers the chromatic dispersion effect and cross-phase modulation (CPM) and stimulated Raman scattering (SRS) effects are dominant effects limiting the TDM bit rate and channel power, respectively     

A high capacity metropolitan area network using lightwavetransmission and time multiplexed switching

The technical feasibility of a lightwave communication system capable of providing service to thousands of subscribers within cities or large suburban areas is examined. Each subscriber in this system has available upon demand an aggregate bit rate of up to 100 Mb/s. The aggregate bit rate of the entire network is on the order of 5 Tb/s. The network topology is that of a star-on-star wherein each subscriber line terminates on one of a multitude of remote concentrators. Each high-speed link from a remote concentrator to a centrally located time-multiplexing photonic switch consists of a single-mode fiber carrying several wavelength-division multiplexed (WDM) channels. Each channel operates in a time-division multiplexed (TDM) mode at a data rate of 2 Gb/s and is powered by a multimode laser. No regeneration is required at the central switch, and at the remote concentrators, each channel is terminated by a direct-detection receiver. The approach achieves high throughput by reusing the same channels, that collectively occupy a tiny fraction of the optical band, among all interconnecting links and, with the exception of large-dimensional switch arrays, employs readily available technology     

Flexible hybrid WDM/TDM PON architectures using wavelength selective switches

For building an optical access network, we propose some new hybrid WDM/TDM passive optical network (PON) architectures that use wavelength selective switches (WSSs) at the remote node to improve flexibility, data security and power budget. Through simulations we demonstrate that the switching capabilities of a WSS can provide additional gains in terms of wavelength usage by a better statistical multiplexing. Several WSS-based hybrid WDM/TDM PON variants are proposed and assessed. These architectures are also compared with the more commonly used hybrid WDM/TDM PONs consisting of power splitters and/or arrayed wavelength gratings (AWGs), in terms of cost and power budget.     

NTT ultra-fast,large-capacity optical transmission at 400 Gbit/s

By combining optical time-division-multiplexing (TDM) and wavelength division-multiplexing (WDM) with a single super-continuum light source NTT Corp. has successfully conducted an ultra-fast, large-capacity optical transmission experiment at 400 Gbit/s (equivalent to sending 100 years of newspapers in a second) over a distance of 100 km. Having already confirmed that the PLL timing extraction circuit and all optical time-division demultiplexer are able to function at 400 Gbit/s and 200 Gbit/s, respectively, NTT plans to continue R&D efforts to develop an optical transmission system exceeding 1 T bit/s.     

Transmission of 622 Mbit/s spectrum-sliced WDM channel over 60 kmof nondispersion-shifted fibre at 1550 nm

The transmission of a spectrum-sliced WDM channel at 622 Mbit/s over 60 km of nondispersion-shifted fibre using an optical bandwidth of only 0.23 nm is reported. This is the highest single channel bit rate-length product (40 Gbit/s·km) and smallest channel bandwidth reported to date for spectrum-sliced WDM systems. The bit error rate performance is theoretically predicted and experimentally confirmed and limits on the bit rate-length products of spectrum-sliced WDM channels using nondispersion-shifted fibre in the 1550 nm window are given     

WDM与TDM技术的比较

WDM与TDM是光传输网可采用的两种主要技术，对这两种技术的实现原理，优缺点以及相互关系作了详细的比较说明，并对未来光传输网如何合理地选择WDM和TDM技术作了一些简要介绍。     

Architectures and technologies for high-speed optical data networks

Current optical networks are migrating to wavelength division multiplexing (WDM)-based fiber transport between traditional electronic multiplexers/demultiplexers, routers, and switches. Passive optical add-drop WDM networks have emerged but an optical data network that makes full use of the technologies of dynamic optical routing and switching exists only in experimental test-beds. This paper discusses architecture and technology issues for the design of high performance optical data networks with two classes of technologies, WDM and time division multiplexing (TDM). The WDM network architecture presented stresses WDM aware Internet protocol (IP), taking full advantage of optical reconfiguration, optical protection and restoration, traffic grooming to minimize electronics costs, and optical flow-switching for large transactions. Special attention is paid to the access network where innovative approaches to architecture may have a significant cost benefit. In the more distant future, ultrahigh-speed optical TDM networks, operating at single stream data rates of 100 Gb/s, may offer unique advantages over WDM networks. These advantages may include the ability to provide integrated services to high-end users, multiple quality-of-service (QoS) levels, and truly flexible bandwidth-on-demand. The paper gives an overview of an ultrahigh-speed TDM network architecture and describes recent key technology developments such as high-speed sources, switches, buffers, and rate converters     

Long Haul System Issues with Bragg Fiber Grating-Based Dispersion Compensation

Using an accurate optical system simulation for Bragg fiber grating dispersion compensators, the fundamental limitations on system performance incurred by these devices operating in reflection and transmission, are studied. When the devices are operating in reflection, the limitation on system performance is due to group delay and reflectivity ripple. When they are operating in transmission, the limitation on system performance is due to dispersion slope of the grating. A range of issues, including the impact on system performance of ripple period and amplitude, concatenating many gratings, and system bit rate are considered. The results show that systems based on WDM with lower channel line rates are the more resilient to limitations introduced by these devices than high-speed TDM systems.