磷钨杂多酸催化合成乙酸乙酯的研究

经实验确定了以磷钨杂多酸为催化剂、乙醇和乙酸为原料合成乙酸乙酯的最佳反应条件为酸醇比为2．0：1～2．5：1，磷钨酸用量为酸质量的2．0％～2．5％，反应时间4h，反应酯化率达94．6％以上。     

钨硅酸催化合成乙酸辛酯

以钨硅酸为催化剂，通过乙酸和辛醇反应合成了乙酸辛酯。探讨了酸醇物质的量比、催化剂用量以及反应时间对酯化率的影响。实验结果表明：钨硅酸催化合成乙酸辛酯的最佳条件为：酸醇物质的量比1．3：1，催化剂用量0．2g／0．1mol(辛醇)，带水剂(环己烷)10mL，反应时间1h．温度100～118℃．在此条件下其酯化率可达99．30％。     

己二酸的绿色合成探究——绿色化学实验在基础有机化学实验中的应用

以30%过氧化氢为氧化剂,用钨磷酸催化氧化环己醇合成己二酸,考察了催化剂用量,反应物配比和反应时间对己二酸产率的影响。当反应物物质的量比为钨磷酸：环己醇：过氧化氢=1：250：1125,在一定温度下回流反应4~6h,产率可达到50%;且催化剂可以重复使用。结果表明：本方法操作简单,无污染,符合绿色化学发展的要求,可用于基础有机合成实验。     

环保型聚磷酸酯阻燃剂的合成研究

以磷酸和尿素为原料,制备聚磷酸铵无机阻燃剂。考察磷酸、尿素、氨水的用量和反应温度对聚磷酸铵平均聚合度的影响,用X射线衍射（XRD）法表征聚磷酸铵的晶体结构,实验结果表明,制备聚磷酸铵的最佳反应条件为n（磷酸）：n（尿素）=1：1．85,反应温度180—220℃,反应时间为150min。聚磷酸铵的平均聚合度为170。以聚磷酸铵和聚醚多元醇为主要原料,合成具有一定含氮量的聚磷酸酯并采用红外光谱分析。聚磷酸酯对聚丙烯阻燃性能测试表明：该阻燃剂可以有效地降低释烟量,不会造成环境污染。     

磷钨杂多酸催化合成丙酸丁酯

以磷钨杂多酸为催化剂，通过丙酸和丁醇反应合成丙酸丁酯，研究了各有关因素对丙酸酯化率的影响．实验证明，磷钨杂多酸是合成丙酸丁酯的良好催化剂．在酸醇物质的量比为1：1．2，催化剂用量1．0％（占反应物总质量的百分数），带水剂环己烷10mL／0．2mol丙酸，反应时间为80min，反应温度100～115℃的条件下，丙酸的酯化率可达99．3％．     

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％．     

高取代度季铵型阳离子化玉米淀粉在处理城市生活废水中的应用

研究了以聚合硫酸铁(PFS)为主凝剂、高取代度季铵型阳离子化玉米淀粉(HQCC)为助凝剂处理城市生活废水的各种影响因素．实验结果表明：PFS和HQCCS分别以200mg／L和10mg／L的复配浓度、pH值接近中性时混凝效果为最佳，CODCr去除率达到80％，色度与浊度去除率均达99％以上．     

大枣、葡萄醋复配饮料的研制

采用单因素试验与正交试验相结合的方案,确定以葡萄皮醋为基料,大枣为辅料研制复配果醋的最佳生产工艺.大枣葡萄醋的最佳工艺配比是：葡萄醋30%,大枣汁25%,蜂蜜5%,所得复配型果醋醋体澄清透明,酸味柔和,营养丰富.复合果醋开发价值高,市场前景广阔.     

Dawson结构钨磷酸复合有机聚合物高质子导体的制备与导电性能研究

摘要：采用Dawson结构钨磷酸（P2W18）与有机聚合物基质（聚乙二醇、聚乙烯吡咯烷酮或壳寡糖）进行复合,制备了一系列有机一无机复合高质子导体材料（PEG／P2W18、PVP／P2W158、COS／P2W18）．通过红外光谱对Dawson结构钨磷酸进行了表征,并通过电化学阻抗谱对Dawson结构钨磷酸及其复合高质子导体材料的质子电导率进行了研究．结果表明P2W18、PEG／P2W18、PVP／P2W18和COS／P。W,8的质子电导率分别为：4．73×10^3 3.71x10^-4、5．75×10^-3和2．78x10-4 S·cm^-1,为新型固体高质子导体。     

杂多配合物催化丁烯二酸环氧化的研究

报道以第一过渡系金属取代型杂多硅钨配合物为催化剂，用过氧化氢水溶液进行丁烯二酸环氧化反应的条件。     

汉字倒说

汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。     

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?     

钱生钱!

我们绝大部分人都同意一件事情——我们喜欢金钱。但是你对金钱的喜欢之情足够到让你创立一份事业么?.财富通常被人忽视,主要在于人们不能真正了     

Inequalities for inscribed simplexes

The problem on the geometrc inequalities involving an n-dimensional simplex and its inscribed simplex is studied. Aninequality is established, which reveals that the difference between the squared circumradius of the n-dimensional simplex andthe squared distance between its circumcenter and barycenter times the squared circumradius of its inscribed simplex is not lessthan the 2(n-1)th power of n times its squared inradius, and is equal to when the simplex is regular and its inscribed siplex is atangent point one. Deduction from this inequality reaches a generalization of n-dimensional Euler inequality indicating that thecircumradius of the simplex is not less than the n-fold inradius. Another inequality is derived to present the relationship betweenthe circumradius of the n-dimensional simplex and the circumradius and inradius of its pedal simplex.     

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.     

微薄的薪水,高尚的情操

现在,我们可以没有面包,没有钱,没有房子,没有车子……但我们唯独不能丢失的是高尚的情操,笃定的信念,还有,满满的希望!     

Virtual reality approach for 3D large model browsing on web site

Using virtual reality for interactive design gives a designer an intuitive vision of a design and allows the designer to achieve a viable, optimal solution in a timely manner. The article discusses the process of making the Virtual Reality System of the Humble Administrator＇s Garden. Translating building data to the Virtual Reality Modeling Language （VRML） is by far unsatisfactory. This creates a challenge for computer designers to do optimization to meet requirements. Five different approaches to optimize models have been presented in this paper. The other methods are to optimize VRML and to reduce the file size. This is done by keeping polygon counts to a minimum and by applying such techniques as object culling and level-ofdetail switching.