最少拍无波纹计算机控制系统的一种综合方法

大部分文献对最少拍计算机控制系统的综合都作了一些假定，因而使综合方法不够完整准确．笔者对闭环脉冲传递函数Φ（Ｚ）的综合方法、问题的提出、分析及解决、系数求取等方面作了一定的完善，从而使Φ（Ζ）的综合更加完整准确，而且直观、简炼．最后，还就最少拍系统对各种典型输入适应性差的问题进行分析讨论，并进一步地提出了一些具体的解决方法．     

基于最小拍无纹波数字化的PMSM速度调节器

研究用最小拍无纹波数字化方法设计永磁同步电动机（PMSM）伺服系统速度调节器.把电机传动过程模型的连续域传递函数转换成数字域z形式传递函数,根据速度指令的z变换输入形式,设定预期误差传递函数,使得在有限拍内能输出稳定的速度信号,然后依据最小拍无纹波零极点配置原则,反推出数字调节器的形式,并使速度调节器输出的电流指令信号...     

一类高阶线性微分方程解的复振荡性质

研究了高阶线性微分方程f（k）＋Ak-1（z）epk-1（z）f（k-1）＋Ak-2（z）epk-2（z）f（k-2）＋…＋A0（z）.ep0（z）f=0和f（k）＋Ak-1（z）epk-1（z）f（k-1）＋Ak-2（z）epk-2（z）f（k-2）＋…＋A0（z）ep0（z）f=F（z）解的增长性问题,其中pj（z）=ajzn＋bj,1zn-1＋…＋bj,n,Aj（z）和F（z）是有限级整函数.针对pj（z）中aj（j=0,1,…,k-1）的幅角主值不全相等的情形,得到了方程解的增长级的精确估计.     

液压转速系统的最少拍控制

文中研究了用于飞机发动机地面模拟台的大功率电液速度伺服控制系统的控制方法.为使系统达到快的响应特性,应用计算机控制手段,采用最少拍控制结合模糊控制的方法.在实验和理论分析的基础上,建立了简化的一阶环节模型和二阶环节模型,分别设计了最少拍控制器,并进行了控制实验.实验结果表明,应用二阶环节模型进行最少拍控制并结合模糊控制,可获得满意的响应特性.     

磁致伸缩的响应速度特性及其校正

本文研究了磁致伸缩微小位移机构的传递函数和动态响应特性;研究了采用单板机进行最少拍校正和等速率双拍校正,进一步提高其响应速度的理论和方法;并利用计算机闭环校正控制系统进行了车床主轴回转误差补偿信号的跟踪模拟实验。提出的等速率校正的控制思想,对于其它类似的控制问题也具有一定的参考价值。     

一类近于凸函数子族的研究

函数g（z）〈G（z）,当且仅当存在单位开圆盘E内的解析函数w（z）∈B0,即满足：w（0）=0,｜w（z）｜〈1,使得g（z）=G（w（z））（z∈E）,设P[A,B]={p（z）：p（0）=1,p（z）在E内解析且满足p（z）〈1＋Az/1＋Bz,-1≤B〈A≤1,一个函数g（z）∈C[A,B]当且仅当（zg＇（z））＇/g＇（z）〈1＋Az/1＋Az.函数族KB＇[A,B]={f（z）：f（0）=f＇（0）-1=0,f（z）在E内解析g（z）∈C[A,B],且Re{zf＇（z）/g（z）}〉B,-1≤B〈A≤1},这是近于凸函数的一个子集,从而这些函数是单叶的．利用Janowski介绍的函数类P[A,B]的性质,参考Khalida Inayat Noor研究CB＋[A,B]的方法,研究这个函数族系数估计和半径问题,同时讨论KB’[A,B]与其他单叶函数子族的关系．     

关于全纯函数的正规定则

本文讨论只有重级零点的情况下正规定则的问题.对有关结果作了推广和改进,得到了①f（z）为只有重级零点的整函数,若fk—af2≠0（a≠0）为有穷复数,k为正整数,则f（z）为常数.②设F（z）为区域D内一个全纯函数,K为正整数,ai（z）（i=0,1,…,K—1）,b（z）,a（z）均在D内全纯,a（z）≠0.若对任意f∈F只有重级零点,fk（z）+sum from i=1 to （k-1）(ai（z）+b（z）f（z）-a（z）f2（z）≠a0（z）则F在D内全纯.     

IM分担一个值的整函数

讨论了整函数IM分担一个值的唯一性,并得到了如下唯一性定理：设f（z）和g（z）是超越整函数,令n,k（≥2）是两个整数且有n〉5k＋7.如果（f^n（z））^（k）和（g^n（z））^（k）IM分担1,则f（z）=c1e^cz,g（z）=c2e^-cz,其中c1,c2,c是满足（-1）^k（c1c2）^nc^2k=1的常数,或者f（z）≡tg（z）,t是满足t^n=1的常数.     

亚纯函数φ（z）f（z）M[f]的值分布

设k和n0,n1,…,nk为任意的非负数,f（z）是复平面上超越亚纯函数,φ（z）为f（z）的小函数,φ（z）0,M[f]=（f（z））n0（f＇（z））n1…（f（k）（z））nk.讨论了亚纯函数φ（z）f（z）M[f]值分布,提出一个新的定理,并进行了较为详细的证明.     

单位圆内解析系数的高阶线性微分方程的解与小函数的增长性

研究了高阶线性微分方程f（k）＋Ak-1f（k-1）＋Ak-2f（k-2）＋…＋A1f＋A0f=0和f（k）＋Ak-1f（k-1）＋Ak-2f（k-2）＋…＋A1f（z） ＋A0f=F解的增长性,其中A0（z）,A1（z）,…,Ak-1（z）,F（z）≠0是单位圆△={z：｜ z｜＜1｜内的解析函数.得到了微分方程解的超级、零点收敛指数与小函数之间的关系.     

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