四水氯化锰催化合成乙酸正丁酯

用四水氯化锰作冰乙酸和正丁醇的酯化催化剂，成功地合成了乙酸正丁酯，考察了影响反应的各种因素，探讨并找到了较好的反应条件：冰乙酸0．30mol.n(冰乙酸)：n(正丁醇)=1．0：1．5(mol/mol)，催化剂用量为5％(反应物总质量的百分数)，反应时间为2．5h，产品收率可达85．3％．     

AlCl_3·6H_20催化合成醋酸异戊酯

以异戊醇和冰乙酸为原料 ,采用六水合三氯化铝作催化剂合成醋酸异戊酯。考察了催化剂用量、原料配比和反应时间等因素对反应的影响。确定了三氯化铝作为催化剂的最佳反应条件 :n冰乙酸∶n异戊醇 =1∶0 .7(摩尔比 ) ,六水合三氯化铝用量为 0 .6g ,反应时间为 3.0h ,转化率 (以 0 .2mol冰乙酸计 )达 94 2 %。     

AlCl3·6H2O催化合成醋酸正丁酯

以正丁醇和冰乙酸为原料,采用三氯化铝(AlCl3*6H2O)作催化剂合成醋酸正丁酯.考察了催化剂用量、原料配比和反应时间等因素对反应的影响.找到了一种无污染、催化活性高的催化剂--AlCl3*6H2O,确定了AlCl3*6H2O作为催化剂的最佳反应条件:醇酸比n正丁醇∶n冰乙酸=1∶0.7,催化剂用量为0.6 g,反应时间为2.0 h,产率高达98.6%(以0.2 mol冰乙酸为基准);并且对催化剂的重复使用效果作了研究.     

AlCl3*6H20催化合成醋酸异戊酯

以异戊醇和冰乙酸为原料,采用六水合三氯化铝作催化剂合成醋酸异戊酯.考察了催化剂用量、原料配比和反应时间等因素对反应的影响.确定了三氯化铝作为催化剂的最佳反应条件n冰乙酸∶n异戊醇＝1∶0.7(摩尔比),六水合三氯化铝用量为0.6 g,反应时间为3.0 h,转化率(以0.2 mol冰乙酸计)达94.2%.     

固体超强酸Fe2O3—SO4催化合成醋酸丁酯的研究

以固体超强酸Fe2O3-SO4为催化剂，醋酸和正丁醇为原料合成了醋酸丁酯，结果表明：正丁醇用量为0．2mol，催化剂用量1．2g，醇酸摩经为1：1．5，反应时间3h，收率达85％以上。     

新型固体酸催化合成乙酸乙酯

以铁钾矾为催化剂,通过乙醇和乙酸反应合成乙酸乙酯,并对影响酯化率的因素进行了研究．结果表明最佳条件为：催化剂用量为0．6g／0．05mol冰乙酸,醇酸物质的量比为1．2：1,带水剂（苯）15mL,反应温度为73～78℃,反应时间为120min,酯化率可达96．78％．     

三氯化铝催化合成醋酸正丁酯的研究

以正丁醇和冰乙酸为原料 ,采用三氯化铝 (AlCl3·6H2 O)作催化剂合成醋酸正丁酯 .考察了催化剂用量、原料配比和反应时间等因素对反应的影响 .确定了三氯化铝作为催化剂的最佳反应条件 ;醇酸比例为n正丁醇∶n冰乙酸 =1∶0 .7;催化剂用量为0 .6g ;反应时间为 2 .0h ;产率高达 98.4% (以冰乙酸为基准 ) .并且对催化剂的重复使用效果作了研究     

固体超强酸树脂催化合成戊二酸二丁酯

以固体超强酸树脂为酯化催化剂合成了戊二酸二丁酯，考察了醇酸摩尔比、带水剂用量、催化剂用量及反应时间对酯化率的影响，通过极差分析，确定了合成戊二酸二丁酯的优化反应条件：以0．25mol戊二酸二丁酯为基准，醇酸摩尔比为3．0，催化剂用量为0．6％，带水剂环己烷24ml，反应时间为90min，戊二酸二丁酯收率可达99．3％以上。     

复合催化剂Hβ沸石／TiO2催化合成乙酸辛酯

采用复合催化剂Hβ沸石／TiO2合成了乙酸辛酯。确定反应的最佳条件为：酸醇物质的量比1：1．1、催化剂用量3．0g／mol乙酸、催化剂中TiO2的质量百分比10％、环己烷用量20mL／mol乙酸、反应时间3．5h。与其它单一固体酸催化剂比较，复合催化剂的催化性能更优越，乙酸的转化率更高。     

硫酸铝催化合成醋酸异戊酯的研究

以异戊醇和冰乙酸为原料,采用硫酸铝(Al_2(SO_4)_3·18H_2O)作催化剂合成醋酸异戊酯.考察了催化剂用量、原料配比和反应时间等因素对反应的影响.确定了硫酸铝作为催化剂的最佳反应条件:n_(冰乙酸):n_(异戊醇)=1:0.6(摩尔比),硫酸铝用量为0.5 g,反应时间1.5 h,产品收率(以0.2mol冰乙酸计)达95.2％.并且对催对剂的重复使用效果作了讨论.     

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