光盘存储技术,产品和市场的发展（下）

本文介绍了在与磁存储技术对比和竞争中各种光盘存储技术的发展，从家用小型光盘系列到专业用数字光存储系统，分析了今后光盘存储技术的发展方向，主要为提高光盘存储密度和数据传输速率，以及需要解决的关键技术问题，并列出了可能发展途径，介绍了光盘技术市场的发展状况，指出它是多媒体技术系统中的主要介质，将成为光电子技术领域中最主要的产业之一。     

丁坝群三维水流数值研究

丁坝是河道整治及防洪护岸工程中一种常见的建筑物,丁坝水流一般是具有不规则的曲面边界和自由表面的三维紊流,本文采用修正的K-ε模型封闭Reynolds方程作为紊流控制方程、引入通度概念处理不规则边界、引入VOF法追踪自由表面,对丁坝群三维水流进行了数值模拟,给出了自由表面形状、流速分布图及回流长度,并与试验结果进行了比较,从水流条件出发,给出了丁坝群间距的推荐值。     

Research Progress on High-Density Optical Storage Materials for Blue-Green Laser Recording

The key for the development of high -density optical storage technology nowadays is to develop short wavelength (blue-green laser) recording media and devices. Based on the progress achieved in the key program of National Natural Science Foundation of China "high-density optical storage materials using blue -green laser recording", the chemical composition, microstructure, storage performance and related mechanisms of some kinds of novel high density optical storage materials are presented in this paper. The research method and clew for super high -density optical storage materials and technologies are highlighted.     

脂肪酸酯季铵盐表面活性剂的合成及其抗静电性研究

由脂肪酸和二甲胺基乙醇进行酯化,再以卤化物季铵化的方法,合成了十二种文题化合物。测定了它们用于腈纶纤维、涤纶纤维及涤纶平绒织物的抗静电效果,讨论了影响抗静电效果的因素。发现月桂酸及棕榈酸的二甲胺基乙醇酯与氯甲烷形成的季铵盐,具有卓越的抗静电性,超过了常用的抗静电剂SN。     

基于均方差权值法的山东省县域城镇化水平评价

在多指标综合评价中,各属性指标权重系数的大小对评价结果有着直接而重要的影响.均方差权值法作为诸多客观赋权法中的一种,较好地解决了主观赋权法无法避免的某些随机性和主观臆断性问题,同时也在一定程度上摆脱了某些客观赋权法存在的局限.文章介绍了均方差权值法的基本原理及其操作过程,并运用该方法对山东省县域城镇化综合发展水平进行了评价,就县域城镇化要素特征进行了深入探讨.结果表明,山东省县域城镇化发展极不平衡,空间分异特征极其明显.从总体上看,城镇化发展水平的空间分布同经济发展和社会发展较相吻合,大致呈现为两轴相交的"┣"型格局.     

Discovering Attack Path Oriented-IP Traceback

The technique of IP traceback may effectively block DOS (Denial Of Service) and meet the requirement of the computer forensic, but its accuracy depends upon that condition that each node in the Internet must support IP packet marking or detected agents. So far, this requirement is not satisfied. On the basis of traditional traeeroute, this paper investigates the efficiency of diseovering path methods from aspects of the size and order of detecting packets, and the length of paths. It points out that the size of padding in probed packets has a slight effect on discovering latency, and the latency with the method of bulk sending-receiving is much smaller than one with the traditional tracemute. Moreover, the loss rate of packets with the technique of TTL (Time To Live) which increases monotonously is less than that with the technique of TTL which decreases monotonously. Lastly,OS (Operating System) passive fingerprint is used as heuristic to predict the length of the discovered path so as to reduce disturbance in network traffic.     

有机化学教材中有机化合物命名存在问题之浅见

对近几年出版的有机化学教材中，有机化合物命名方面存在的一些问题进行了讨论     

跨世纪的信息存储

一、信息存储市场将成为下世纪信息领域的主要市场　　众所周知，冷战结束后，发达国家对世界争夺的重心已经转移到信息领域。由于信息高速公路具有军民兼容、深度军备和国家利益等特征和倍增国力的功能，当前发达国家及一些发展中国家都先后制定了本国“信息高速公路”计划，不仅全面规划本国国家利益在信息领域的发展方向，还特别具体规定了本世纪末和２１世纪初所要达到的目标。根据预测，全球的信息量今后几年会以更快的速度增长（见图１）。当前信息的发展以多媒体化和数字化为主要特征。由于信息的多媒体化，人们需要处理的不仅是数据…     

Short-wavelength static optical recording properties of subphthalocyanine thin films

The static optical recording properties of novel bromoboron trinitro-subphthalocyanine (BTN-SubPc) thin films were studied using a self-developed short-wavelength optical disk tester with high NA objective lens. High reflectivity contrast (>30%) was obtained at low writing power (8 mW) and short writing pulsewidth (200 ns) using the Ar⁺ laser (514.5 nm) irradiation. These results demonstrate that subphthalocyanine is not only qualified for red-light recording but also a promising candidate for the recording medium of a green-light DVD-R. The leading edge, just like the falling edge, of the dye’s absorption band can also be used to realize optical disk storage if an appropriate reflector was used. It provides a new clew for double-wavelength writing/reading and choosing short-wavelength recording materials.     

Study on read-only optical disk with Sb mask super-resolution

In this note, by using Sb to replace the Al reflective layer in the conventional optical disk, the recording pits with a diameter 380 nm and a depth 50 nm are read out in the device, whose laser wavelength l is 632.8 nm and numerical aperture (NA) is 0.40. In the course of reproduction, the readout laser power is 4 mW and the rotation velocity of the disk is 5 m/s. The optimum Sb film thickness is 28-30 nm and the CNR is 38-40 dB.