基于Markov链的集束型晶圆制造设备预防性维护建模

为了有效提高集束型晶圆制造设备的运行可靠性,同时降低其维护成本,提出了基于Markov链的预防性维护建模方法.根据集束型晶圆制造设备的特点,将设备使用情形分为运行状态、预防性保养状态、保养未能回复状态、预防性维修状态和维修无法回复状态,建立了设备状态转移模型.在此基础上,建立了集束型晶圆制造设备的预防性维护成本模型,进行了仿真实验分析.结果表明,该模型可有效分析不同参数组合下的单位时间预防性维护期望成本.     

混合Petri Net在制造系统建模与仿真中的应用

针对大批量制造系统,建立了一种有效的建模仿真工具——混合Petrinet(PN),并对其进行了数学描述。在混合PN中,连续节点被用来表示大容量库所和短时变迁,解决了传统的离散PN在仿真过程中存在的可达状态爆炸和仿真时间过长的问题。对离散PN和混合PN在事件数量和仿真时间方面进行了比较;运用混合PN对某汽车冲压加工单元进行了建模和仿真,并对其输出缓冲区的容量进行了优化设计,明显提高了设计和分析的效率。     

钢铁企业轨梁万能生产线仿真建模

针对钢铁企业的轨梁万能生产线在生产中存在的新产品调试生产周期过长、生产瓶颈不易诊断、设备利用率低等问题,分析了钢铁企业轨梁万能生产线不同于传统离散制造以及流程制造过程的特点,在此基础上建立了半连续半离散的轨梁万能生产线的Petri网模型和各设备的仿真组件模型,开发了轨梁万能生产线的仿真系统,并用一个实际的工程应用案例,验证了该仿真模型及其系统的可操作性以及有效性,达到了提高生产现场轨梁万能生产线的生产效率和产能的目的.     

基于随机流网络与Markov过程的制造系统可靠性建模及维护优化

针对制造系统中设备数量与输入的不确定性,考虑制造过程中的不良品以及不良品的返工情况,分析系统可靠性与各设备数量、设备输入的关系,建立基于随机流网络的制造系统可靠性评价模型.采用齐次Markov过程对系统衰退和维护进行状态分析,以最小化维护成本为目标,以系统可靠性为约束,建立系统设备的维护模型.通过算例分析,验证该模型的有效性和先进性.     

混流制造系统的Petri网建模与仿真研究

以赋时Petri网为分析工具,将混流制造系统工艺流程、产品类型标识、缓冲区和加工时间等用基本Petri网语言表示,建立了基于赋时库所Petri网的混流制造系统模型,从全局观点描述事件之间的顺序、并发和同步等关系,并基于该模型,进一步分析混流制造系统的性能,包括操作间的逻辑约束关系、资源冲突、生产能力和设备利用率等.相关实例的仿真结果证明了该模型的有效性.     

可重组制造系统车间设施动态重构研究

针对制造系统车间设施重构的决策问题,给出了面向可重组制造系统车间设施动态重构方法.利用多色图理论着色原理定义设施围道,建立制造车间多色图模型,通过布尔矩阵生成车间作业单元配置模型和物流模型,并构建工艺可行的作业单元配置方案;利用仿真分析软件构建作业单元配置方案的数字化仿真模型,结合生产物流及设施利用率分析,重构作业单元内设施系统.以某公司机械加工车间为研究对象,验证了车间设施动态重构过程的可行性和有效性.     

基于Flexsim的制造车间生产线仿真优化研究

对制造企业生产线优化能有效降低运营成本。某制造生产车间同时生产三种产品,加工设备、生产线复杂。为提高生产效率,采用Flexsim仿真软件建立生产线模型,并通过仿真试验分析现有生产线瓶颈;采用增加加工设备、增加搬运设备及采用柔性生产调度方法等三种方案对生产线进行优化;结果表明,优化后的生产线投入产出率提高了13.83%,车间生产趋于平衡,同时,设备利用率也得到提高。     

基于PN的可重入医学检测调度系统优化研究

基于一类具有可重入特点的医学检测过程的设备调度问题,研究了具有约束条件的优化解.首先分析了调度约束条件和优化目标,建立了其Petri Networks(PN)形式化模型,并分析了其规则调度系统的稳定性和其他性能.然后利用PN模型和调度约束条件解出调度可行解结合对医学检测部分工序要求连续的基础上建立时间约束矩阵,对可行解进一步优化,最终得到满足所有约束条件的优化可行解.通过对实际医学检测系统的实例分析和CPN Tools仿真,结果表明所建立的模型和方法的有效性.     

蜂窝移动通信基站的离散时间排队分析

用有限用户离散时间损失制系统对蜂窝移动通信基站进行建模,利用Markov链方法,给出稳态下系统每一时隙上发生损失的概率、平均信道利用率和平均吞吐率等性能指标。并通过数值仿真解释了该模型对数字蜂窝移动通信网络设计及性能分析的应用。     

基于NSGAⅡ的生产线缓存与设备布局协同优化

为解决因布局过程忽略或粗略设置缓冲区占地面积而造成的生产拥挤或空间浪费问题,针对缓存配置与设备布局问题展开协同优化.基于连续时间Markov随机过程原理建立排队网节点状态模型,求解生产线设备平均利用率.以设备利用率、物料搬运距离和占地面积为优化目标,建立缓存配置与设备布局协同优化模型.通过改进的NSGA-Ⅱ算法对该模型进行优化.最终,通过某柴油机缸体生产线实例验证了本文提出方法的有效性.     

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