数字式彩色电视机

在国外,一种新型的数字式彩色电视机正在进入家庭。目前,美国、日本、联邦德国、英国和荷兰等国都在积极发展数字式彩色电视机。作为世界最大潜在电视机市场的我国,第一台数字式彩色电视机已由华南工学院研制成功。我们知道,现行的电视制式中,视频信号是连续变化的模拟信号,这种制式存在清晰度不高和重影等,虽经努力,仍难以进一步提高电视的性能,而数字式彩色电视机就可解决这些问题。数字式彩色电视机的主要标志就是以数字电路代替模拟电路,使那些     

DDS在电子测量与仪表中的应用

介绍了直接数字式频率合成（DDS）技术的基本工作原理及其DDS在电子测量与仪表中的应用，并对相位截断条件下DDS的输出频谱进行了分析．     

柴油机数字式电子调速器

提出了一种采用ＭＣＳ－８０９８单片机控制的柴油机数字式电子调速器．通过单片机对柴油机转速进行数字ＰＩＤ调节，克服了传统机械式调速器的许多缺点．实验表明该调速器能够满足大多数中高速柴油机不同工况下的调速要求．     

全彩色立体打印成型机——ZPrinter

美国ZCorp．公司研制出了一种全彩色立体打印成型机——ZPrinter，它可以把照相机拍摄的物体自动制成立体模型，并且快速“打印”出全彩立体模型来。比如对一些珍贵的文物古董器皿，只要有了足够的数据，很快就可以通过这种“全彩色立体打印成型机”获得这些古玩的逼真仿制品。也可以用于制作工业新产品的试验模型，或者制作医用骨骼模型等等。     

电子温度计的设计及其测量误差分析

分析PN结的温度特性,设计制作了指针式电子温度计和数字式电子温度计,根据实测数据对温度测量误差作了定量分析。     

某型涡扇发动机数字式综合电子调节器研制

为解决某型涡扇发动机模拟式综合电子调节器普遍存在的使用寿命与发动机使用寿命不相匹配、监控水平不高、虚警不断等问题,以该型综合调节器为研究对象,完成了该型发动机数字式综合电子调节器的软、硬件系统设计.为了提高系统的可靠性,调节器内部设计了双余度硬件系统,并由系统的切换电路选择工作正常的硬件参与工作.工作过程中控制系统采用热备份的工作状态,并接收主控通道的工作信息,使备份通道始终跟随主控通道,从而保证控制系统平稳转换.最后对所设计的数字式综合电子调节器进行了试验,试验结果表明所设计的数字式综合电子调节器合理可靠并满足实际使用中的需求.     

数字式HDTV何以克服现行电视制式的缺陷

本文论述了在黑白彩色兼容框架下的现行电视制式存在缺陷的主要原因,分析了数字式高清晰度电视机制能提高电视图象清晰度、消除闪烁的主要方法和物理机理。     

浅谈数字式电子汽车衡偏载误差调整方法

在对电子汽车衡检定时,发现数字式电子汽车衡,可以通过仪表软件自动调整其偏载,一遍加载即可完成偏载调整,免除了打开接线盒行反复手工调试的麻烦,简单方便,提高了工作效率,也提高了电子汽车衡的准确度.     

如何做好TD2-A型数字式电子探空仪的施放工作

介绍了TD2—A型数字式电子探空仪施放前的准备工作、探测资料的接收工作和探测资料的整理工作。     

数字式汽车衡检定分析

论述了数字式汽车衡的首次检定、后续检定和使用中的检验,进行了检定前的分析,详细阐述了电子汽车衡各称量点的检定及计算。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the