共查询到20条相似文献，搜索用时 93 毫秒
1.
对叔丁基杯芳烃合成及性能研究的综合实验 总被引：3，自引：0，他引：3
文中对叔丁基杯芳烃的合成和性质研究设计为本科生综合实验。用对叔丁基苯酚和37%的甲醛在碱性条件下合成了对叔丁基杯[4]芳烃、对叔丁基杯[6]芳烃和对叔丁基杯[8]芳烃,并对三种产物进行了结构检测,还比较了三种杯芳烃对铜离子萃取能力的大小。 相似文献
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林洪梅 《沈阳教育学院学报》1999,(Z1)
杯芳烃是由苯酚和甲醛在酚羟基邻位缩合而成的一类大环化合物.因为它是由多个苯环构成的芳香族分子,且分子形状酷似希腊圣杯,由此得名杯芳烃.杯芳烃的命名习惯上写成“杯[n]芳烃”.n为苯酚环的个数.例如对位由特丁基取代的环状四聚体写成“对特丁基杯[4]芳烃”.如果取代基较复杂时,可根据Chemical Abstract方式,按图1中的编号进行命名.如上述化合物可命名为“5,11,17,23—四特丁 相似文献
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采用紫外光谱和荧光光谱对杯[4]芳烃衍生物A与Ce(Ⅲ)的配合物进行了研究.实验结果表明,配合物在λ=250nm产生一个新的紫外吸收峰,同时Ce(Ⅲ)可产生λex,max=254 nm,λem,max=361 nm的自身荧光.而杯[4]芳烃A在一定条件下能淬灭其荧光,可见杯[4]芳烃衍生物A在稀土分离与提取中有潜在的应用价值. 相似文献
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采用气泡式准乳化液膜法,研究了不同条件下对－叔丁基杯[4]芳烃对三磷酸腺苷（ATP）的传输影响,并对其传输规律及传输机理作了初步探讨。 相似文献
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研究了乙酰异丙胺基取代和丁基取代杯[4]芳烃聚硅氧烷固定相的合成.按此合成路线得到的杯芳烃衍生物产率高,约为60%. 相似文献
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近20年来的研究表明,各种杯芳烃在模拟酶催化、物质的分离和检测、功能材料等领域有着广阔的应用前景.本文选用难分离的位置异构体对所制备的杯[4]芳烃聚硅氧烷固定相色谱柱进行了应用研究.结果表明,含有杯芳烃衍生物的混合固定相,对多数芳香族位置异构体化合物均有良好的选择和分离能力. 相似文献
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将四种杯芳烃衍生物，即分别含乙酰异丙胺基和丁基的杯芳烃衍生物与OV—1701的混涂固定相(C[4]A：OV—1701和C[4]B：OV—1701)，及其聚硅氧烷(PSO—C[4]A和PSO—C[4]B)制备成毛细管拄，对其相变温度进行测定，并对色谱拄的热稳定性作了对比分析．结果表明，聚硅氧烷化的杯芳烃衍生物相变温度较高，分别为137℃和122℃，热稳定性较好，可在高温下使用． 相似文献
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对-叔丁基杯[6]热力学及热分析动力学研究 总被引：1，自引：0，他引：1
用热重TG和DSC对对-叔丁基杯[6]的热分解过程进行了研究,用"DSC-TG"结合法推断出了对-叔丁基杯[6]热分解的可能过程,求出了其热分解反应动力学方程及热分析动力学参数;其热分解的过程为四号机理函数,为球型三维扩散过程.其动力学方程为:f(a)=3/2[(1-a)1/3-1],活化能为168.7KJ.mol-1,指前因子为8.54×1037S-1. 相似文献
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通过杯[6]芳烃六乙酸乙酯与多乙烯多胺进行氨解反应,合成了系列酰胺型杯[6]芳烃聚合物,它们对软金属离子具有较高的吸附容量,其吸附能力与聚合物中杯芳烃的含量成正比,在吸附过程中杯芳烃单元起决定性作用． 相似文献
11.
罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 相似文献
12.
Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 相似文献
13.
Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F. 相似文献
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《海外英语》2007,(5):10-11
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? 相似文献
17.
陈美曦 《山东教育学院学报》2008,23(2):103-107
Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language. 相似文献
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邱崇丙 《唐山师范学院学报》2014,(1):21-23
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。 相似文献
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《海外英语》2007,(4):36
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. 相似文献