纳米型H3PW12O40/SiO2催化合成MMF

采用单因素方法进行合成富马酸单甲酯的研究.以顺丁烯二酸酐、甲醇为原料,纳米型固载杂多酸H3PW12O40/SiO2为催化剂,产品收率可达85%以上.     

防霉剂富马酸单甲酯的合成研究

以马来酸酐和甲醇为原料,无水AlCl3为异构化催化剂,合成了富马酸单甲酯.考察了影响收率的因素,其优化合成工艺条件为:n(甲醇):n(顺酐)=1.1:1,在60℃下酯化反应0.5 h,无水AlCl3用量为反应物总质量的4%,80℃下异构化2 h,收率可达到84%以上.     

介绍一个综合化学实验——十聚钨酸盐催化绿色合成苯甲酸

作者合成了一种十聚钨酸十六烷基吡啶催化剂．通过红外光谱方法对其结构进行表征,以质量分数为30％的H2O2为氧化剂,在回流温度下,十聚钨酸盐催化氧化苯甲醇可得到产率（基于苯甲醇）为90％-93％的苯甲酸。这是一条苯甲酸绿色合成的新途径,克服了目前有机化学实验教材中采用的浓HNO3或KMnO4氧化法存在的污染大、反应时间长等缺点。     

新型防腐剂富马酸二甲酯的合成研究

在固体酸S04^2-/ZrO2-MoO3催化下，由马来酸酐和甲醇催化合成富马酸二甲酯(DMF)。探讨了催化剂用量，原料配比，反应时间对DMF产率的影响，确定了最佳反应条件为：醇酸摩尔比为6：1，反应时间3h，催化剂用量1．5％，该条件下，产物收率达93％以上。     

硅钨酸催化合成富马酸二甲酯

研究了以硅钨酸为催化剂，以富马酸和甲醇为原料合成富马酸二甲酯的方法。讨论了影响酯化反应的各种因素，并得出了酯化反应的最佳工艺条件：醇酸比为6：1，催化剂硅钨酸用量为酸质量的6％，15ml环己烷为带水剂，反应时间4h，酯化率达92．7％。与浓硫酸、氯化铁、硫酸氢钠催化剂作比较，实验结果表明以硅钨酸为催化剂具有催化剂用量少、重复使用效果好，反应时间短，酯收率高，方法简单等优点。     

β-硝基苯乙烯合成方法改进

提供一种快速高效合成周俊峰 -硝基苯乙烯的环境友好合成法．分别研究了在超声波辅助Henry反应和甲醇助剂存在Claisen-Schmidt反应的条件下由苯甲醛、硝基甲烷合成周俊峰 -硝基苯乙烯的反应条件，发现Claisen-Schmidt反应条件下收率最高，产率为84％。     

2—戊基蒽醌的合成

以叔戊苯和苯酐为原料,通过酰基化和关环合成了２－戊基蒽醌,改进和优化了各步合成工艺条件,酰化收率８０．２％,关环产品收率８１．４％。     

富马酸二甲酯的合成研究

采用顺酐、甲醇、盐酸为原料合成富马酸二甲酯，并对有关影响因素进行了研究。     

微波促进磺化炭催化合成月桂酸甲酯

探讨了从山苍籽核仁油中分离出的月桂酸在微波辐射下,用活性炭磺化制得固体磺化炭作为催化剂与甲醇酯化合成月桂酸甲酯.对月桂酸与甲醇酯化反应条件进行优化,其优化条件是:反应温度为160℃,反应时间20 min,催化剂用量0.1 g.月桂酸甲酯的酯化率达92.97%.产物经过红外光谱表征.     

磷钨杂多酸催化合成富马酸二甲酯

研究了以磷钨杂多酸为催化剂,以马来酸酐和甲醇为原料合成富马酸二甲酯.反应的最佳条件是:马来酸酐和甲醇的物质的量比为1∶6,催化剂用量为马来酸酐质量的8%,反应时间6h,产率达91.7%.     

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.