固体超强酸TiO_2/SO_4~(2-)催化合成丙酸苄酯

以固体超强酸 Ti O2 /SO2 - 4 为催化剂 ,环己烷为带水剂 ,合成了丙酸苄酯 .考察了催化剂制备 ,催化剂用量 ,原料配比 ,反应时间等因素对酯化率的影响 ,其最佳反应条件为 :醇酸摩尔比 1∶ 3,催化剂用量 1 g,反应时间 1 .5h,反应温度 95～ 1 1 0℃ ,酯化率达到 88% .     

十八水硫酸铝催化合成氯乙酸异戊酯

以Al2SO4318H2O为催化剂,氯乙酸和异戊醇反应合成了氯乙酸异戊酯,研究了醇酸物质的量比、催化剂的用量、带水剂的用量、催化剂反复使用次数及反应时间等因素对酯化率的影响.结果表明:Al2SO4318H2O对氯乙酸异戊酯的合成具有良好的催化活性,当氯乙酸为0.10mol,异戊醇为0.14mol,催化剂的用量为反应物总重量的1.5%,带水剂环己烷的用量为7mL,反应时间1.5h,反应温度105~118℃时,酯化率可达96.5%.     

微波辐射下水合硫酸铁催化合成丙酸环己酯

用水合硫酸铁作催化剂,以丙酸和环己醇为原料,在微波辐射条件下,合成了丙酸环己酯.系统考察了微波辐射功率、辐射时间、醇酸物质的量比、带水剂用量、催化剂用量等因素对酯化率的影响.研究表明反应的最佳条件为:微波辐射功率700 W,固定丙酸用量0.05 mol,醇酸物质的量比为3∶1,水合硫酸铁用量为1.5 g,带水剂环己烷用量为6 mL,反应30 min后酯化率达94.4%.     

微波辐射水合硫酸铁催化合成乳酸环己酯

研究了以水合硫酸铁为催化剂、乳酸和环己醇在微波辐射下进行酯化反应时,醇酸物质的量比、反应时间、催化剂用量、带水剂用量、微波功率等因素对酯化率的影响.结果表明：当醇酸物质的量比为2∶1、催化剂水合硫酸铁用量为2.5 g、反应时间为25 min、带水剂环己烷用量为6 mL、微波功率为640 W时,酯化率达到91.9%,为该酯化反应的最佳条件.     

杂多酸H_6PMo_9V_3O_(40)催化合成乙酸乙酯

以磷钼钒杂多酸H6PMo9V3O40为催化剂,通过乙酸和乙醇反应合成乙酸乙酯.分别考察了醇酸摩尔比、催化剂用量、回流时间对酯化率的影响,实验结果表明:H6PMo9V3O40具有良好的催化活性;酯化最佳反应条件为:醇酸摩尔比2∶l,催化剂用量为反应体系总质量的3.5%,回流反应时间为25 min,酯化率达80%以上.     

硫氢酸钠催化合成氯乙酸异丙酯

以硫酸氢钠作为催化剂合成氯乙酸异丙酯,研究了醇酸摩尔比、催化剂种类、催化剂用量、带水剂种类以及带水剂用量对合成氯乙酸异丙酯的酯化反应的影响.在醇酸摩尔比1.2/1、催化剂用量1.0%(以酸的摩尔数计量)、反应时间2.5 h、反应温度为回流温度以及10 mL环已烷作为带水剂的反应条件下,酯化率可达97.1%.     

硫酸钛催化合成丙酸丙酯

以硫酸钛为催化剂催化丙酸与正丙醇的酯化反应合成了丙酸丙酯,研究了催化剂用量，醇酸摩尔比，反应时间，带水剂用量对酯化反应的影响，在最佳工艺条件下丙酸丙酯的收率为96．5％。     

对甲基苯磺酸催化合成乙酸仲丁酯

以对甲基苯磺酸为催化剂、对乙酸和仲丁醇间的酯化反应进行了研究,考察了催化剂用量、醇酸物质的量比和反应时间对酯化率的影响.其最佳反应条件为：乙酸用量为0.1 mol时,催化剂用量为0.4 g,仲丁醇与乙酸的物质的量之比为1.2：1,环己烷作带水剂,反应1.5 h,酯化率可达94.4%.     

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。     

稀土固体超强酸SO_4~(2-)-TiO_2-La~(3 )催化合成癸二酸二乙酯

研究以稀土固体超强酸 SO2 -4-Ti O2 -L a3 为催化剂 ,癸二酸和无水乙醇为原料 ,合成癸二酸二乙酯 ,并考察影响反应的因素 .结果表明 ,最适宜的反应条件为醇酸摩尔比 4.0∶ 1,催化剂用量 1.0 g (癸二酸 0 .1mol) ,带水剂苯 15 m L,反应时间 3.0 h.酯化率达 96 .8% .     

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.     

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     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has