分配的非线性偏离对难分离多组分色谱流出特性的影响

本文用微扰方法讨论了分配非线性对难分离多组分流出特性的影响,并给出了分配的非线性偏离对流出特性影响的近似表达式.     

用计算机模拟方法讨论分配等温线的非线性对流出曲线的影响

用计算机模拟方法给出了分配等温线非线性项K_1较小情况下的色谱流出曲线;计算了K_1=0,K_1>0,K_1<0不同情况下的偏态特性(三次中心矩μ_3c)。结果表明,从塔板理论出发,用模拟方法得到的非线性色谱流出曲线的偏态特性与微扰方法及数值分析方法得到的结果一致。     

非线性条件下的塔板理论模型和计算机模拟

以非线性吸附等温线方程Langmuir方程为例,创建了一种非线性条件下塔板理论模型的色谱流出曲线的计算机模拟方法,用此方法模拟非线性条件下的色谱流出曲线,能直观地看到吸附系数和样品量对色谱峰拖尾的影响,此模拟程序用于一些大学的色谱分析教学,效果很好。     

转矩分配策略在SRM中的应用及其优化

转矩脉动较大是开关磁阻电机(SRM)的主要缺点。为了减小转矩脉动,提高电机性能,将转矩分配策略应用到电机中。由于开关磁阻电机的非线性,在转矩分配策略中,传统PID控制器的效果受到了限制。考虑到神经网络对非线性系统的自学习和自适应能力,提出采用RBF神经网络PID控制器进行优化。仿真结果表明,转矩分配策略有效抑制了转矩脉动,优化后的转矩分配策略获得了更好的性能。     

开关磁阻电机转矩分配策略的优化

转矩分配策略是近年来开关磁阻电机(SRM)转矩控制中比较流行的一种控制策略,旨在通过合理的分配电磁转矩,达到平稳换相、减小转矩脉动的目的.SRM的非线性特性使得固定形状的转矩分配函数(TSF)无法在整个转速范围内既能抑制脉动,也能保持高效率.文章提出了一种基于常规转矩分配策略的以转矩/安培比最大化为目标的优化方案,在允许的转矩误差范围内在线调整电机的开关角度,保证输出转矩的前提下降低绕组中通过的相电流.在Matlab/Simulink软件中分别建立了常规转矩分配方案和优化方案的直接瞬时转矩控制系统模型.比较分析仿真结果得出,优化后的转矩分配方案在保证合理分配电磁转矩的同时,提高了SRM的效率.     

复杂系统辨识的网络初始化算法

针对用于非线性辨识的连续激发函数的神经网络 ,提出一种根据被测对象非线性特性设计网络初值的算法。这种方法分析了双曲函数 f(x) =tanh(x)敏感区分布和神经网络的灵敏度对网络输出的影响 ,根据样本 ,求出敏感区宽度 Gb,网络隐层权值与 Gb成反比 ,同时满足网络的第 K层权值小于 (K- 1 )权值。电动机非线性磁场的辨识表明这种初始化算法不仅使辨识精度有所提高 ,且加快了网络的收敛速度。     

理想非线性色谱中非平衡偏离对流出的影响

在一级近似下讨论了非平衡偏离对非线性色谱流出的影响,讨论了K→∞的极限情形,井将结果与D的影响进行了比较.     

色谱峰的流出曲线方程

从塔板理论导出的色谱流出曲线方程是正态分布峰,用它可判断目前一般教科书中所叙述的流出曲线方程的正确性。本文详述了色谱流出曲线方程的特性,判别了七个公式的正确性。同时,还讨论了流出曲线方程所能解决的问题与不足。     

基于异类传感器的战场运动目标识别算法

利用异类传感器的互补特性,提出了一种新的运动目标识别算法:选取目标速度、第1主频、第2主频作为识别的有效特征;运用模糊推理得到目标分类信息的基本概率分配函数;把D-S证据推理和基于概率分配函数的决策相结合,获得对目标的有效识别.仿真结果证明了该算法的有效性.     

理想非线性双组分色谱方程解析解与GC实验结果的比较

在理想非线性单组分色谱分析的基础上，用ＧＣ做了理想非线性双组分色谱的流出曲线。在非线性条件下，得出了各组分不同温度下的保留时间和最大浓度值。理想非线性双组分色谱的数学模型的解析解则通过双组分模型的理论公式结合计算机求解，解析解与实验结果进行了比较。     

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