单回路PID控制系统参数整定算法的仿真研究

用计算机仿真过程控制系统ＰＩＤ调节器的工程整定法，即采用凑试法，衰减曲线法，临界比例度法和响应曲线法等，研究了改变ＰＩＤ调节器的比例（Ｐ），积分（Ｉ），微分（Ｄ）参数对系统过渡过程性能的影响，得到了仿真响应曲线。     

一种新型自校正PID励磁调节器的研究

提出了一种新型的同步发电机自校正比例－积分－微分（ＰＩＤ）励磁调节器。该调节器以加权的多变量（电压偏差加转速偏差）作为反馈信号，运用最小二乘估计在线辨识同步发电机的参数以及零－极点配置的设计方法，实时改变ＰＩＤ调节器的增益系数ｋＰ，ｋＩ，ｋＤ，从而实现同步发电机励磁的自适应优化控制。数字仿真计算结果表明，自校正励磁调节器能够自动适应同步发电机运行条件及网络结构的变化，可以获得比恒定增益的ＰＩＤ励磁调节器更好的发电机端电压和功角的响应特性。     

基于极点配置的自适应PID调节器

提出一种新的自适应ＰＩＤ（比例－积分－微分）调节器。与现有的自适应ＰＩＤ调节器方案相比，它不仅算法简单，而且自整定方法所需的先验信息甚少，适用范围广。文章给出它的工作原理和设计方案，讨论了它的性能和实现问题。理论分析和仿真实验证实了该设计方法的有效性。     

专家自适应PID控制系统仿真

针对固定参数的控制器不能满足特性经常变化的控制系统要求的问题，给出了一种专家自适应ＰＩＤ（比例积分微分）控制器的设计及其仿真程序。该设计使用了临界比例度法、响应曲线法、模型识别法及积分分离控制算法，给出了模型识别法的公式及具体的整定规则。实验结果表明，当系统特性发生变化时，该控制器的控制效果明显优于固定参数控制器控制效果。     

控制系统中PID预测方法的实质研究

控制系统的滞后是难免的，滞后系统的预测理论和方法研究一直是控制工程中的重要课题，本剖析了工业中常用的比例－积分－微分（ＰＩＤ）预测方法的实质，指出ＰＩＤ调节器一个按二阶自回归模型进行控制的系统。笔接着分析了ＰＩＤ调节器的预测误差，高于二阶的系统用ＰＩＤ方法预测时误差很大，从理论上得到到良好的控制效果。ＰＩＤ只能适用于某些特场合，中探讨了使用方法。     

全程优化增益调度控制

提出了一种全程优化增益调度控制策略。与常规ＰＩＤ（比例－积分－微分）调节器相比，它具有适应性强和调节品质好等优点。给出了该控制策略的工作原理和设计方法，以及用于发电机励磁系统的仿真实验结果。     

模糊PID增益调节器的算法,结构及硬件实现

提出了一种模糊ＰＩＤ增益调节器算法。通过模糊推理在线调整ＰＩＤ控制器的参数,从而改善控制效果。仿真结果表明,模糊ＰＩＤ增益调节器在稳定时间、超调和均方误差上均比传统ＰＩＤ控制有较大的改进。     

控温系统品质的比较和评定

本文试对ＰＩ（比例积分）、ＰＤ（比例微分）和ＰＩＤ（比例积分微分）三种复合控温系统的品质──稳定性、稳态误差和动态响应等作一比较和评定，以期选择最佳控温系统．     

PID控制参数的整定方法

在分析常用的ＰＩＤ（比例积分微分）控制器控制参数的整定方法（扩充临界比例度法、扩充响应曲线法、模型识别法）的同时，给出了其中几种方法的操作步骤。用微机对典型对象进行实验研究，通过改变被控对象的参数，分别研究了用上述三种方法整定控制器参数的适应能力。提出了用模型识别法确定控制器整定参数的规则，给出了识别系统特征参数的方法。实验结果表明，模型识别法参数调整方便，适应能力强，应用范围广，较其他方法控制效果优越。     

位置伺服系统PID控制器参数在线整定算法

为了使ＰＩＤ控制器参数能够在线自动调整,获得最优或次优的控制器参数,提出了基于浮点数编码遗传算法（ＧＡ）的位置伺服系统ＰＩＤ控制器参数在线整定算法（ＧＡＣＰＴ）,设计了相应的改进遗传操作,同时提出了通过运动学习保证控制器稳定鲁棒性的适合度函数设计方法．完成一次ＰＩＤ控制器参数在线整定只需１０ｍｉｎ,效率较人工整定有很大提高．对一个实际机电位置伺服系统的仿真研究表明,ＧＡＣＰＴ算法能够在对象参数未知时,使系统阶跃响应趋于期望曲线,高效地完成ＰＩＤ控制器参数在线整定．该方法可用于数控机床位置伺服控制、过程控制等一般工业控制系统,以及机器人高精度轨迹控制系统．     

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