并励直流电动机的机械特性分析

分析了他励直流电动机的机械特性,然后分析并励直流电动机的机械特性,并与他励直流电动机的机械特性相比较,得出它的不同点：空载转速不随电压U_a变化,而机械特性曲线的斜率随U_a的增大而减小。这为更好地使用并励直流电动机提供理论依据。     

求异步电动机机械特性的一种简易方法

异步电动机是应用最广泛的一种电动机.对机械类学生和工程技术人员来说,为了能设计高质量的机械产品,正确使用机械产品,就要选择和使用异步电动机,了解异步电动机的性能.机械特性是异步电动机最重要最基本的特性之一.如何能在他们现有的理论基础上进一步提高,并能用简易的方法作出较理想的机械特性曲线来,这是一个非常有实用意义的工作.本文就是在这个基础上提出了作异步电动机机械特性的方法,以供参考.     

GDJC型高压断路器机械特性智能测试仪研制成功

高压断路器的机械特性是否满足指标,关系到电力系统能否安全可靠地运行,在出厂前、投运前均需测试其机械特性。高压断路器的机械特性是指其动触头的速度特性和断口的时间特性。传统的测试方法存在着读数不直观、精度低、难于测量自动重合闸等缺点。随着电力工业的发展,需要一种使用方     

电动机机械特性的超声波测量方法

在介绍利用超声波测量电动机机械特性原理的基础上,对具体的测量方法、实验结果、测量范围做了论述,指出此方法可用于电动机机械特性的大批量测试。     

感应电动机串级调速机械特性方程

指出了应用现行的感应电动机串级调速机械特性方程进行计算时出现的问题；提出了另一种表达形式的机械特性方程．     

绕线式异步机串频敏变阻器的机械特性分析

本文采用变压器空载串联等值电路的方法,对频敏变阻器的频敏特性进行分析,并利用异步电动机机械特性的参数表达式,对绕线式异步电动机串频敏变阻器的机械特性进行分析。     

载体驱动硅微机械陀螺的电学模型研究

本文针对载体驱动硅微机械陀螺的动力学特性，建立了基于微机械陀螺机械振动特性和电学特性的等效电路模型，利用电学模拟工具Pspice对模型进行了验证。模拟分析与实验结果表明，采用机电模拟方法建立的微机械陀螺电学模型可替代动力学模型，用于接口电路的设计与仿真， 利用该模型设计的电路能满足载体驱动硅微机械陀螺性能指标的要求。     

三相异步电动机机械特性的直观表达式

推导通过三相异步电动机机械特性的直观表达式，表明了改变哪些参数就能改变其机械特性的斜率β，以达到调速的目的。     

分析高压开关机械特性检测仪应用中所遇问题及处理措施

高压供配电是常见的工程项目应用之一,其中,高压开关是一种常见的真空断路器,在施工使用之前需要进行必要的机械特性测试。高压开关的机械特性测试仪就是通过现代光电隔离技术来测试高压开关机械特性的一种重要设备,适用于各种型号的断路器、接触器、继电器和空气开关等。     

新型混合式液压机械复合变速器的特性分析

针对单行星排液压机械复合变速器存在变速范围有限,抗负载能力不强等问题,提出了一种新的混合式液压机械复合变速器(HMCVT),建立了混合式液压机械复合变速器特性的统一关系式.利用AMESim软件对混合式液压机械变速器进行了仿真.对样机进行了试验,得出了混合式液压机械无级变速器的工作特性曲线,并与输出耦合式复合变速器进行了对比.结果表明:混合式液压机械复合变速器的实际调速特性曲线和理论值一致,液压机械复合变速器具有无级调速功能;混合式液压机械复合变速器速度线性度更好,更容易调节;混合式复合变速器的液压功率分流比在0到1.0之间,不存在功率循环,机械效率较高.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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