在金色大厅聆听

2003年的圣诞前夕，我随中国电影电视技术学会声音委员会组织的中国高级录音师考察团踏上了出访奥地利、德国的音乐之旅。之所以把此行称为音乐之旅，是因为我们所到之处，总被浓浓的音乐氛围包围着。十几天的行程使我们深深地感受到：奥地利、德国不愧是培养音乐家和录音师的摇篮。尤其使我难忘的是此行第一站——在金色大厅的聆听……     

在维也纳金色大厅听交响音乐会

维也纳是世界著名的音乐之都,世界著名的音乐家如莫扎特,贝多芬、海顿、舒伯特、勃拉姆斯、斯特劳斯父子,瓦格纳等都曾工作生活在这个美丽优雅的城市。他们的乐曲激荡着多瑙河的波浪,他们的歌声回旋在古老的歌特与巴洛克风格的建筑之间。我的一位朋友讲：”就连维也纳的鸣禽也耳嚅目染受到音乐的熏陶,叫声也格外动听。”据说维也纳大大小小的音乐厅有200多家,要知道维也纳的常住人口也不过100多万。     

证券交易在可视图文业务中的应用

可视图文(Videotex)是一种公用的、交互型的信息服务系统.它可以通过公用分组网或Internet网将社会各地的信息互联起来,实现全社会的信息资源共享.它覆盖面广,安装使用方便,用户只需利用可视图文终端,通过现有的公用电话网和公用分组网,检索查询全国各地的信息.目前,可视图文业务有检索和交易两大功能.前者指用户只能查询信息,但不能通过终端直接处理各种事务;而后者能使用户通过终端完成各种买卖、交易合同.例如车票预订、订货购物、外汇买卖、证券委托、期货买卖等商贸交易.可视图文证券交易系统的开发成功,使可视图文的应用从单一的信息查询转向了商贸交易领域,这标志着可视图文正在迈向一个新阶段.     

证券交易离不开通信

证券交易离不开通信曹永秋我国古典神话小说《封神演义》里就有“顺风耳”、“于里眼”奇特功能的故事。Ｌ大这种幻想直到近百多年来，才由电话的发明开始变成现实。电话这八奇怪的发明把我们讲话的声音转变成电信号，经一对电线传输出去，然后又把它转换成声音。这种声音...     

数据广播在传输证券交易行情中的运用

贵州电视台用图文电视数据广播传输证券交易行情,本文介绍了该播出系统运用于网络之上,对行情和文件数据完成接收,转换,播出及用户管理等;、介绍其系统结构图及数据流程等。     

互联网实时证券交易系统

随着Ｉｎｔｅｒｎｅｔ应用的飞速增长和业务覆盖面的逐步扩大,ＷＷＷ应用已从简单信息检索、业务介绍及软件下载等初级应用,发展到实时信息发布、在线交易等高级应用。国际金融市场、证券市场一体化和电子商业化步伐加快,传统的银行业、证券业的经营环境已随着Ｉｎｔｅｒｎｅｔ的出现和推广发生了巨大变化。国内证券业的传统交易方式也受到了Ｉｎｔｅｒｎｅｔ的冲击,越来越多的券商和投资者关注着网上交易的发展。1　证券业应用Ｉｎｔｅｒｎｅｔ的优势Ｉｎｔｅｒｎｅｔ在证券业中的应用可提供多种优势,具体介绍如下:ａ.Ｉｎｔｅｒｎｅｔ凭借…     

证券交易信息安全保险研究

本文通过撰写本报告给保险公司提供一个在中国的证券行业开设网络交易安全保险险种的可行性建议,并为保险公司提供以下证券保险答案:市场多大、发展趋势怎样、开什么险种、如何理赔。     

证券交易网络改造方案

本文介绍了一种将10M证券交易网改造为100M网的设计思想。     

Theoretical analysis of hall factor and hall mobility in p-type silicon

Using a two-band (i.e. heavy-hole and light-hole band) model and the relaxation time approximation, the Hall factor was calculated for the case of silicon doped with boron. Contributions from scattering by acoustical and optical phonons and by ionized and neutral impurities were considered. In addition, the effects of hole-hole scattering, as well as valence band nonparabolicity and anistropy were also taken into account. The scattering and anistropy factors were separately evaluated to emphasize their individual contributions to the Hall factor. Theoretical values of the Hall factor at 300 K vary between 0.882 and 0.714 over the dopant density ranges 10¹⁴ ≦ N_A ≦ 3 × 10¹⁸ cm^?3. Hall mobilities for p-type silicon were calculated and compared with published data 100 ≤ T ≤ 400 K and 10¹⁴ ≦ N_A ≦ 3 × 10¹⁸ cm^?3. The present model is limited to the case of uncompensated material and for the weak field in which μ_HB ? 1.     

Technology takes to securities trading

The Internet and other communications technologies are changing the way financial markets operate. Some markets will be full-service marketplaces, others will provide only certain services, and others will be ill-defined-such as smart agents on the Internet. Technology will allow orders to be routed to the most appropriate market. So the market of the future is likely to be a glass box of markets with different but transparent trading opportunities accessible through technology. The result will be seamless electronic trading, around the clock and around the world, with investors buying and selling individual stocks, currencies, commodities and mixed portfolios. Trades will be based on a variety of parameters. Liquidity will be provided primarily by investors, as opposed to intermediaries. Settlement will occur in real time. Multiple types of competing markets and market centers will provide multiple services. Transaction costs will fall to competitive levels on a worldwide basis. Technology will help us achieve this goal, but foresight and thoughtful proactive regulation are also necessary. Let us hope that, if the technical community keeps providing the former, the government will try hard to provide the latter     

Influence of the skin-effect on hall voltage in semiconductors

The Maxwell equations were solved for the case of perpendicular semiconducting plate in which Hall voltage arises under operation of the permanent magnetic field and h.f. input current. The dependence of the Hall plate impedance and Hall voltage on frequency was considered. The numerical calculations of these dependences were made.     

The accuracy of the relaxation solution for the potential problem of a hall plate with finite hall electrodes

The potential values of the relaxation method are converted to the values of the geometrical coefficient and the Hall side resistance. As a guide to the accuracy of the data obtained from the relaxation method, these converted values are compared with the known conformal transformation solutions. A conclusion is found upon the variation of the geometrical coefficient and the Hall side resistance with the mesh size and the Hall electrode length. The paper concludes by demonstrating new data which may be difficult to obtain by the analytical method.     

An optical alternative to the hall test

Effective mass ratios, m*, of electrons in n-type InSb, GaAs, and near intrinsic and n-type Hg_1−xCd_xTe for 0.20 < × < 0.30 over the temperature range 77K < T < 296K were measured using Faraday rotation spectroscopy. m* ranged from 0.0186 to 0.0357 for InSb with carrier concentrations, N, in the range 1.76 < N < 110 × 10¹⁶ cm⁻³ at 296K, in good agreement with available values in the literature. Effective masses of HgCdTe were found to be about twice as large at room temperature as band edge effective mass, m*_be calculations. These calculations can be corrected for thermal excitation by adding a factor, m**, to the band edge calculation: m* = m** m*_be, where m** was found empirically to be m** = 4.52 × 10₋₃T + 0.78. The electron’s mobility is proportional to the ratio of the electron’s Faraday rotation to its absorption; that is, the absorption due to the intraband transitions of the electron itself, not the sample’s total absorption, which may include holes, interband transitions, and the like. The constant of proportionality, or the “mobility constant”, was measured in n-type GaAs and InSb doped above 18 × 10¹⁶ cm⁻³ using absorption directly. Both HgCdTe and InSb have large intrinsic carrier concentrations, on the order of 10¹⁶ cm⁻³. Hole absorption is the majority component of the sample’s absorption at lower n-type dopant concentrations. In these cases, the mobility constant was determined using an absorption cross section.     

Nonlinearity in hall devices and its compensation

Three types of nonlinearity effects can be distinguished in Hall devices: material, geometrical and junction field-effect nonlinearity. Material nonlinearity, a magnetic field dependence of the Hall coefficient, is experimentally characterized for n-type silicon as a function of carrier concentration and temperature. Geometrical nonlinearity, which is due to the short-circuiting effects by the sensor contacts, is related to the geometrical correction factor. It is shown that material and geometrical non-linearity can mutually cancel. Junction field-effect nonlinearity comes about as a modulation of the plate thickness in junction-isolated, integrated Hall devices. The junction field-effect can also be used to compensate nonlinearity.     

新加坡滨海艺术中心音乐厅的声学特性

新加坡滨海艺术中心音乐厅是目前全世界声学规模最大、声学设置最复杂和齐全的音乐厅，并采用混响室来控制音乐厅自然混响。对该音乐厅的设计思想、结构特征、声学控制机构以及音乐厅建成后实测的声学特性作了比较全面的介绍。