BP人工神经网络在聚合物溶液体系活度预测中的应用

应用不同BP人工神经网络对不同聚合物溶液体系的活度进行了训练,共12个系统,613个数点,总的平均相对误差为0．0263,在采用相同BP人工神经网络对聚合物PS与不同溶剂溶液体系的活度进行试练时,总的平均相对误差为0．0212,而利用相同BP人工神经网络对同一聚合物不同溶剂溶液体系的活度进行预测时,总的平均相对误差为0．0484。     

用原子吸收光谱法测定交联聚合物中的铬含量

用原子吸收光谱法直接测定了聚丙烯酰胺中的铬含量，并对影响铬测量值的因素进行了分析。实验结果表明，加人交联剂可有效地提高聚合物溶液的粘度，改善聚合物的抗温、抗盐、抗剪切的性能，从而提高聚合物驱油效果。对空白试剂进行了考察，该测量方法的相对标准偏差为2．3％，试样加标回收率达到95％～105％。铬的检出限为0．016mg/L。实际测定了不同浓度聚丙烯酰胺中的铬含量，测量结果的相对误差小于1％。     

烃类混合物及油气藏流体的粘度计算模型

根据ｖａｎｄｅｒＷａａｌｓ单流体混合规则,将基于两参数ＰｅｎｇＲｏｂｉｎｓｏｎ状态方程的流体粘度计算模型应用于烃类混合物及油气藏流体粘度的计算。对３种二元烃类混合物（甲烷丙烷、甲烷正丁烷和甲烷正癸烷）的粘度进行了计算,２４３９个数据点的平均相对误差为１６．７２％．计算了９种天然气及１７种油藏原油的粘度,其平均相对误差分别为９．８０％和１７．２９％．这种模型优于现有的油气藏流体粘度模型。     

乙醇-水混合溶剂中尿苷酸浓度与溶液密度的关系

获取尿苷酸溶析结晶动力学参数须测定其溶液浓度变化，针对密度法浓度在线测量技术，研究了乙醇-水混合溶剂中尿苷酸(Uridine-5’-monophosphate)质量浓度与溶液密度的关系。20℃条件下，测定了尿苷酸在不同质量分数乙醇．水混合溶剂中的溶解度和溶液密度，以及混合溶剂质量分数一定时的尿苷酸质量浓度和溶液密度。实验结果表明：乙醇一水混合溶剂中，溶液体积与尿苷酸质量浓度具有较高的相关性，可以拟合得到三元溶液体系尿苷酸质量浓度与溶液密度的变化关系式。     

高压流体气液相导热系数模型的建立

对温度Ｔ、导热系数λ和压力ｐ三者之间的关系进行了分析,建立了一个能够同时预测纯组分气液相导热系数的统一模型,它能够描述高压流体和超临界流体的导热系数随温度和压力的变化。在较宽的温度和压力范围内（Ｔ＝８０～１４００Ｋ,ｐ＝０．１～３５０ＭＰａ）,对油气藏流体中常见组分的气液相导热系数进行了计算,２２个组分３２６３个数据点的拟合结果的平均相对误差为１２．５３％。通过引入常规的状态方程混合规则,将模型拓展应用于混合物导热系数的计算,１３种二元和三元混合物２６０个数据点的平均相对误差为１１．１９％;对３个石油馏分２２个点导热系数的预测结果的平均相对误差为８．８９％     

超高相对分子质量聚乙烯溶液的制备

讨论了超高相对分子质量聚乙烯粉末在矿物油及矿物油与煤油的混合溶剂中的溶胀、溶解,并测定所得溶液在不同温度下的落球粘度。结果表明:聚乙烯的最佳溶胀温度随混合溶剂中煤油质量分数的增大而降低;溶液粘度随聚乙烯质量分数的升高而升高,随溶液温度的降低而升高;溶液粘流活化能随聚乙烯质量分数的升高而升高;采用混合溶剂时,溶液粘度随溶剂中煤油质量分数的升高而降低,且煤油质量分数越高,其溶液的粘流活化能越小。     

高压流体气—液相导热系数模型的建立

对温度Ｔ、导热系数λ和压力ｐ三者之间的关系进行了分析，建立了一个能够同时预测纯组分气－液相导热系数的统一模型，它能够描述高压流体和超临界流体的导热系数随温度和压力的变化。在较宽的温度和压力范围内（Ｔ＝８０－１４００Ｋ，ｐ＝０．１－３５０ＭＰａ），对油气藏流体中常见组分的气－流相导热系数进行了计算，２２个组分３２６３个数据点的拟合结果的平均相对误差为１２．５３％。通过引入常规的态方程混合规则，将模型     

粘度法测定高聚物分子量实验的改进

针对高分子材料与工程专业实验＂粘度法测定高聚物分子量实验＂存在的问题进行了改进,利用能够摄像的现代先进仪器设备代替传统的秒表测定高聚物溶液或溶剂在乌氏粘度计中的流动时间。实践表明,改进后的实验与传统的实验方法相比具有许多优点：高聚物溶液流动时间测试结果更为准确,测试效率得到提高,能够摄像的实验器材来源广泛。     

高分子溶液表面张力的测定、关联与预测

采用吊环法测定了聚二甲基硅氧烷(PDM S,1 000 mm2/s)在甲苯、环己烷、丁酮以及环己烷和丁酮混合溶剂中的表面张力随浓度的变化关系。在P rigog ine-D efay模型的基础上,引入了高分子链节有效浓度的概念,获得了相应的计算高分子溶液表面张力的改进模型,该改进模型对实验数据关联的平均相对误差为0.59%;对PDM S(1 000 mm2/s)在丁酮-环己烷混合溶剂体系的表面张力预测的平均相对误差为0.44%。     

应用BP神经网络预测超临界CO2的摩尔体积

用BP神经网络，在1．017≤pr≤8．134和1．019≤Tr≤5．917的范围内，对798组超临界CO2的p—V—T数据进行训练和预测，预测160组，平均相对误差为2.01％；用RK、RKS及PR状态方程法计算这160组数据，平均相对误差分别为2．66％、3．24％和2．48％，表明神经网络法优于状态方程法。     

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