常减压蒸馏装置生产计划与过程操作的优化集成

为确保石化企业得到可行的最优生产计划,并确定实现计划的操作条件,将石化企业的生产计划与过程操作进行了优化集成.提出了石化企业优化集成的一般策略: 利用GIOPIMS优化得到生产计划,采用过程模拟软件求得实现计划的装置操作条件,根据模拟结果来修正生产计划模型并再进行优化,经过决策→检验→修正的求解过程,实现生产计划和装置过程操作的优化集成.根据常减压蒸馏装置的特点,提出了该装置实现优化集成的具体解决方案.并以某炼油厂常减压蒸馏装置炼制长庆油为例验证了该优化集成方案.     

非结构网格在周期性充分发展流动数值模拟中的应用

为了解决周期性充分发展流动数值模拟的计算复杂性，该文提出了非结构网格上周期性边界进出口条件相互回代的方法。应用此方法对横掠叉排管束周期性充分发展层流流动进行了数值模拟，并将其结果与流动进口内8个管束层流流动的充分发展区域的数值模拟结果进行了比较，得到了较一致的结果。实验表明：单周期上进出口条件相互回代的方法可以替代多周期的数值计算，从而简化了计算过程，节省了计算时间。     

银催化剂上乙烯选择氧化反应的强制周期操作

本文以乙烯在银催化剂上的选择氧化反应作为模型反应,通过实验研究证明,在适宜的周期操作条件下,反应器的操作特性优于最佳稳态.在此基础上,从反应机理、动态响应和周期操作特性相互关系的角度,对这一重要体系作了进一步的研究,从而在理沦上对这一体系在周期操作下时均性能的改善作了解释.     

3种水文模型在淮河息县流域洪水模拟中的比较

选用新安江模型、TOPMODEL模型和SWAT模型这3种具有代表性的水文模型,对淮河息县流域洪水过程进行模拟,并对它们的模型结构、汇流方法和模拟结果进行比较。结果表明：新安江模型和TOPMODEL模型模拟结果略好于SWAT模型,说明结构复杂、考虑全面的分布式模型在洪水模拟中结果不一定最优;SWAT模型的最大优点不在于洪水模拟,而在于其考虑因素全面,适合做各种条件下的水文变化研究;这3种模型各有优缺点,下一步可以考虑如何采用集合预报的方法取长补短,提高模拟精度。     

金融混沌Duffing-Holms模型及其控制方法研究

分析并发掘了金融混沌的Duffing-Holms模型的序参量,提出了DuffingHolms模型存在周期解的条件,这表明可以通过OGY方法和非线性同步方法对金融混沌进行控制.在进行OGY控制时,设定了Duffing-Holms模型的一个周期解,并通过数值模拟将混沌控制到该轨道上,结果指出要对中国金融市场进行有效的混沌控...     

乙烯环氧化固定床膜反应器性能CFD模拟分析

为了提高乙烯氧化合成环氧乙烷反应体系的选择性，建立了乙烯由膜管进料的固定床膜反应器模型，对其进行了相关的计算流体力学（CFD）计算模拟，并与传统固定床反应器作比较。结果表明：在反应器构型、催化剂、反应条件相同的前提下，相较于传统固定床反应器而言，固定床膜反应器的选择性较高但乙烯转化率和环氧乙烷收率较低；改变操作条件使得两种反应器的选择性相同时，固定床膜反应器中乙烯转化率和环氧乙烷收率较大。据此得出固定床膜反应器较传统固定床反应器更具优势的结论。本文工作为乙烯环氧化固定床膜反应器的放大与固定床膜反应器替代传统固定床反应器的可行性提供了理论基础。     

汽提法脱除2，4-二硝基甲苯的模拟与分析

采用平衡级模型法，对TDI生产过程中产生的含2，4-二硝基甲苯（DNT）废硫酸的汽提过程进行了严格的计算机流程模拟，分析了汽提压力、蒸汽用量和理论板数对汽提效果和硫酸浓度的影响，得到了优化的操作条件．适宜的操作条件为：压力20kPa左右，蒸汽用量与原料量之比为1：10左右，理论板数7～9块．针对优化后的操作条件进行了汽提小试实验，实验结果与计算机模拟结果相一致，表明优化后的操作条件可用于指导实际生产．     

一类随机互惠模型的遍历性和最优收获策略

讨论一个非线性生物互惠模型在随机扰动环境下的性质特征,以及最优收获策略问题.为了解模型系统的动力学特征,首先利用随机方程的比较原理证明系统解的存在唯一性,并给出两物种平均持续存在的条件;然后利用集合和遍历的方法得到最优收获策略的表达形式,且利用数值模拟直观表现物种在捕获条件下的生长情况,并与所得的理论结果吻合;这帮助人...     

滞育影响下的蜱虫种群动力学模型及分析

目的 研究滞育产生的时间延迟对蜱虫种群动力学模型的影响.方法 分析正平衡点的存在性,并利用中心流形定理和规范形理论,研究分岔周期解的方向和稳定性.结果 给出了滞育对系统稳定性的影响,得到了模型出现Hopf分岔的分岔条件、周期解及其性质.结论 通过实验仿真验证了理论分岔值与数值模拟结果的一致性.     

炼油厂气分装置生产计划与工艺条件的集成优化

为在操作指标受到限制且要满足产品质量要求时,也可保证得到可执行的生产计划,建立了生产计划与工艺条件的集成优化模型。在该模型中,加入工艺条件约束,利用生产计划优化软件与流程模拟软件结合求解。在求解非线性优化模型时,使用了逐次反馈修正装置收率限制的迭代方法。加入了判断生产计划是否可行以及求解不可行物流的收率限制。对某炼油厂气体分离装置生产计划与工艺条件进行集成优化。结果表明,该模型可以得到最优的可行生产计划,有实用价值。     

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