Sol—Gel固定磷钨酸催化合成乙酸丁酯

制备了正硅酸乙酯凝胶（Sol-Gel)固定磷钨酸催化剂，催化合成乙酸丁酯，实验表明，Sol-Gel与磷钨酸的质量比为15：1时催化性能最高，在催化剂用量为总反应物质量为5％，酸醇比为1．5：1，反应温度为105度，反应时间为3．5h的条件下，酯产率可达87％以上，催化剂易与产物分离，重复使用8次催化效果仍然较好。     

无毒增塑剂乙酰柠檬酸三丁酯的合成

用固体氯化物催化合成柠檬酸三丁酯,柠檬酸三丁酯和乙酸酐反应合成乙酰柠檬酸三丁酯。研究了催化剂用量、原料配比、反应温度、反应时间对合成反应的影响,确定了最佳工艺条件：（１）酯化反应：柠檬酸∶正丁醇为１∶３．５（ｍｏｌ）;反应温度为１３０℃;反应时间５ｈ,催化剂用量０．７％;（２）乙酰化反应：柠檬酸三丁酯∶乙酸酐为１∶１．６,反应温度为８５℃,反应时间为１ｈ,催化剂用量为０．０６％。酯化收率为９６．３％,乙酰化收率为９８．５％。     

钛酸四丁酯催化合成柠檬酸三丁酯

以柠檬酸和正丁醇为原料，钛酸四丁酯为催化剂合成柠檬酸三丁酯，用单因素分析法研究醇酸摩尔比、催化剂用量、反应时间及反应温度对酯化反应的影响。结果表明，酯化反应的最佳条件为：n(醇)：n(酸)：3．6：1.0，催化剂用量为柠檬酸质量的0．40％，反应时间4h，反应温度130～140℃，酯化率达到94．51％，纯度大于99．1％。     

活性炭负载磷钨酸催化合成三醋酸甘油酯

研究了用活性炭负载磷钨酸催化合成三醋酸甘油酯的反应．考察了磷钨酸的负载量、醇酸比、催化剂用量、带水剂种类和用量对反应的影响，并且对其他催化剂的催化活性进行了比较．结果表明：活性炭负载磷钨酸是合成三醋酸甘油酯的优良催化剂；在优化条件下，三酯产率达86．4％，纯度99．2％；催化剂可重复使用。     

正交试验法合成柠檬酸三丁酯

采用柠檬酸和正丁醇为原料合成柠檬酸三丁酯。通过正交试验考察了催化剂种类、醇酸摩尔比、反应时间及反应温度对酯化率的影响,从而确定了最佳合成工艺条件为：采用一水舍硫酸氢钠为催化剂,醇酸摩尔比为4：1,反应时间为2．5h,反应温度为115℃,柠檬酸三丁酯的酯化率可达96．94％。     

硫酸氢钾催化合成柠檬酸三丁酯

采用硫酸氢钾作催化剂,对柠檬酸与正丁醇间的酯化反应进行了研究。考察了催化荆用量和醇酸摩尔比对柠檬酸三丁酯酯化率的影响。实验结果表明：以0．02mol柠檬酸为基准,醇酸摩尔比7：1,催化剂的用量1．5％（质量百分比）,反应时间2h,酯化率可达94．54％。     

磷钨酸催化合成水杨酸正丁酯的研究

以环境友好试剂磷钨酸为催化剂对其催化合成水杨酸正丁酯的反应进行了研究，利用正交实验法得出了该反应的最优化条件，即醇酸摩尔比为2：1，催化剂用量为酸质量的7％；反应时间为4h。酯产率可达80．5％。实验表明该催化剂催化活性高。选择性好，对设备无腐蚀，是一种环境友好的催化剂。     

四氯化锡催化合成柠檬酸三丁酯的研究

本文研究了以四氯化锡水合物作催化剂催化合成柠檬酸三丁酯,确定了酯化优化条件。实验结果表明,醇酸摩尔比为4：1,柠檬酸用量为0．2mol的情况下,催化剂用量为反应物质量的2．5％,带水剂甲苯15ml,反应时间80min,反应温度为108－148℃是最佳反应条件,酸的酯化率达到96．23％。     

磷钨酸催化合成香料苯甲醛正己硫醇缩醛

用大孔阳离子交换树脂和磷钨酸制得离子交换树脂固载磷钨酸催化剂，用此催化剂合成了苯甲醛正己硫醇缩醛，考察了影响其收率的因素．发现催化合成的优化条件为：苯甲醛：正己硫醇：催化剂：二氯甲烷=0．1mol：0．215mol：2．0g：35．0mL，43℃回流下进行，反应时间5．0h，收率可达86．3％，由此可见，离子交换树脂固载磷钨酸为催化剂对苯甲醛和正己硫醇缩醛反应具有较高的催化活性，且稳定性较佳，可重复使用．     

活性炭负载磷钨酸催化合成香料乙酸异丁酯

利用负载磷钨酸为催化剂合成乙酸异丁酯,以异丁醇和冰乙酸为合成原料,反应条件温和,反应速度快,产率高。探讨并找出最佳条件,在醇酸摩尔比为1：1．6,催化剂用量占反应物总量的7．23％。反应时间为100min时,得到的乙酸异丁酯产率最高,为91．28％。     

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