水杨酸戊酯的催化合成

以对甲苯磺酸为催化剂，通过水杨酸和戊醇酯化反应合成水杨酸戊酯、研究了催化剂用量、酸醇物质的量比以及反应时间等因素对水杨酸酯化率的影响．实验结果表明，对甲苯磺酸是合成水杨酸戊酯的良好催化剂．在酸醇物质的量比为1：1．6，催化剂用量为6％，带水剂甲苯10mL，反应时间5h，反应温度120～140℃的条件下，水杨酸的酯化率可达94．1％．     

富马酸双十二酯的合成

以富马酸和十二醇为原料,对甲苯磺酸为催化剂,合成了富马酸双十二酯。运用正交实验法考察了反应时间、反应温度、原料配比及催化剂用量对酯化的影响。     

活性炭负载硅钨酸催化合成柠檬酸三丁酯

用活性炭负载硅钨酸催化剂催化柠檬酸与正丁醇酯化合成柠檬酸三丁酯.对柠檬酸与正丁醇酯化反应条件进行优化,其优化条件是:在酸醇的摩尔比为1:6.0,催化剂的负载量为18%,催化剂用量为柠檬酸质量的1.2%,反应温度为150℃,反应时间4小时,柠檬酸的酯化率达92.3%,产物经过红外光谱表征.     

硅钨酸掺杂聚苯胺催化剂催化合成苹果酯

自制了硅钨酸(H4SiW12O40)掺杂聚苯胺(PAn)催化剂H4SiW12O40／PAn．以乙酰乙酸乙酯和乙二醇为原料合成苹果酯．较系统地研究了原料摩尔比、催化剂用量、反应时间诸因素对产品收率的影响．实验表明：最佳反应条件为n(乙酰乙酸乙酯)：n(乙二醇)=1：1．5。催化剂用量为反应物料总质量的0．5％。环己烷为带水剂，反应时间1．0h．上述条件下．苹果酯的收率为71．5％．     

Dawson型锌钨酸配合物催化苯乙烯氧化制苯甲醛正交试验研究

文章以Dawson型锌钨酸配合物催化苯乙烯氧化制苯甲醛反应为模板,利用正交试验来优化反应条件.通过实验得到：反应时间达到20h,反应温度达到50℃,催化剂用量达到1.5g,过氧化氢用量达到4.0ml条件下,反应的酯化率可达89.5％,反应选择性较高.催化剂的重复使用表明杂多酸具有优良的催化选择性能.     

壳聚糖硫酸盐催化合成苯甲酸乙酯

研究了以壳聚糖硫酸盐作为催化剂，由苯甲酸和乙醇为原料合成苯甲酸乙酯的反应条件，重点讨论了催化剂用量、酸醇摩尔比与反应时间对酯化率的影响。实验表明，壳聚糖硫酸盐是合成苯甲酸乙酯的良好催化剂，且可重复使用。通过正交试验确定最佳反应条件为：催化剂用量为苯甲酸用量的4．1％；醇酸摩尔比为5：l；反应时间为3h。此条件下，酯化率为86．5l％。     

钨硅杂多酸催化合成桂皮酸正戊酯

以钨硅杂多酸为催化剂，通过桂皮酸和正戊醇酯化反应合成桂皮酸正戊酯，研究了各有关因素对桂皮酸酯化率的影响．实验证明：钨硅杂多酸是合成桂皮酸正戊酯的良好催化剂，在酸醇物质的量比为1：2．5．催化剂用量1g／0．05mol桂皮酸，带水剂苯7mL，反应时间为1．5h条件下，桂皮酸的酯化率可达99．2％．     

脱铝超稳Y沸石催化合成对羟基苯甲酸异戊酯

本研究了脱铝超稳Y沸石催化对羟基苯甲酸与异戊醇的酯化反应，考察了催化剂硅铝化、催化剂用量和反应时间对酯反应的影响。结果表明，在优化反应条件下，反应在6h内完成，酯转化率达58．0％同时，对水杨酸与异戊醇的酯化反应也进行了研究。     

固体超强酸SO42-/TiO2的制备及催化合成苯甲酸异戊酯的工艺研究

以固体超强酸为催化剂，用苯甲酸和异戊醇两种原料，直接酯化合成苯甲酸异戊酯．首先制备固体超强酸SO4^2-／TiO2，然后以此为催化剂进行酯化反应．反映过程中，考察了反应温度，原料配比，催化剂用量，反应时间等酯化反应的影响，由此确定最佳合成工艺条件：反应温度170℃，反应时间3h，异戊醇和苯甲酸摩尔比4：1，催化剂用量2％（以体系总质量计算）．由此条件下，其中苯甲酸异戊酯的收率达87．50％．     

TiSiW12O40/TiO2催化合成甲酸丁酯

介绍了新型催化型TiSiW12O40/TiO2的制备方法，实验考察了以自制的该催化剂催化合成甲酸丁酯的酸醇化，催化剂用量，反应时间等因素对反应产率的影响，实验表明：在酸醇物质的量比为2．5：1，催化剂用量为反，反液的1．78％，酯化反应时间为40min，反应温度为94－98℃时，反应产率可达72．2％。     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

库克斯顿城堡

城堡, 是欧洲典型的建筑之一, 每个城堡都有一个美丽的传说或是一段历史。从本期开始, 我们将推出“城堡之旅”, 带各位读者去浏览、观赏欧洲各地的城堡, 开始一段文化与历史的旅途!     

The Reader Response Approach to Teaching of English Literature

During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context.