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单酯基芳香醛及芳香腈类液晶的合成与液晶相研究 总被引：1，自引：0，他引：1
以对羟基苯甲醛、对羟基苯腈,与4-正丙基苯甲酸、4-正丙基联苯甲酸为主要原料,通过氯化、酯化等方法,合成了四个多环单酯基类液晶：4-正丙基苯甲酸-4′-氰基苯酚酯,4-正丙基苯甲酸-4′-醛基苯酚酯,4-（4-（4-正丙基联苯）酰氧基）苯甲醛,4-4-（4-（4-正丙基联苯）酰氧基）苯腈。产物结构经元素分析、IR及MS表征,化合物的液晶相通过DSC及POM（偏光显微镜）确定。结果表明其中2个化合物具有热致液晶性,呈典型的向列项纹影织构。 相似文献
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以2,7-萘二酚,1,5-萘二酚和对甲基苯甲酸,对丙基苯甲酸以及对乙基环己基甲酸为原料,合成了4个萘二酚酯类液晶化合物,其中3个为香蕉型分子,1个为棒状分子。产物通过红外光谱仪、气-质联用仪(GC-MS)、紫外-可见分光光度计进行结构表征,采用示差扫描量热仪(DSC)及偏光显微镜(POM)研究了化合物的液晶行为。结果表明,所合成的这类萘环衍生物具有液晶的性质。 相似文献
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设计合成对-7-辛烯羰氧基苯甲酸(A)和对-7-辛烯羰氧基苯甲酸胆固醇酯(B),采取红外(FT-IR)、 核磁(1H-NMR)、质谱(MS)及元素分析法对其结构进行表征。用DSC分析B的相变温度,发现在78.3 ℃出现第一个相变峰,在123.4 ℃到达了各向同性的液相,介晶温度范围也较宽。用POM观察B液晶相态,选取90 ℃时进行拍摄出现明显的片状有序排列,说明化合物B具备液晶性能。 相似文献
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合成了一种既有液晶性又有光敏性的多功能化合物4-[4-(4-丙基苯酰氧)苯偶氮]苯甲醛,运用差热扫描量热分析（DSC）、偏光显微技术（POM）研究了化合物的液晶相性质,运用紫外光谱分析法研究了其紫外光照射后的光反顺异构化过程。结果显示,该化合物具有典型的液晶相性质,且液晶相温度范围宽;同时,该化合物能够发生光致反-顺异构化反应,在甲醇或者THF溶液中反-顺光异构反应为一级速率过程。 相似文献
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合成了由没食子酸醚和没食子酸酯形成的树状小分子化合物,研究其液晶相性质。以没食子酸,正丁醇等为主要原料,通过醚化、催化酯化、室温酯化等反应步骤,合成以没食子酸为基本结构单元的目标化合物;通过元素分析、1HNMR、IR及MS表征其结构;通过DSC及偏光显微镜测试其液晶性质。结果表明,以没食子酸为中心结构单元可以合成树状小分子化合物,该树状分子具有较低的熔点,并显示出热致液晶性。 相似文献
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介绍了光致变色液晶化合物的分类及光致变色液晶高分子在信息存储领域的应用.综述了光致变色液晶小分子化合物研究进展及其应用前景.总结了光致变色液晶材料光调控的方式. 相似文献
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运用AM1和PM3两种SCF-MO方法,通过能量梯度全优化计算,给出5种1-甲氧基环己硅烷类液晶化合物(联苯基乙烷类系列)的稳定几何构型、电子结构和生成热、偶极矩、前沿轨道能级等性质,并结合有机电子理论进行了分析和讨论。 相似文献
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从3-硝基-4-氯苯甲酸,通过碱性水解、催化加氢及脱盐三步反应,合成得到3-氨基-4-羟基苯甲酸.结果表明,最佳NaOH水解量为5.0～5.5eq,时间为3.5h;正交试验催化加氢较佳条件为：H2压力为0.25Mpa,pH在5.4～5.6,反应温度为100℃,催化剂5%Pd-C的用量为2.5%（3-硝基-4-羟基苯甲酸）.氢化后粗品经重结晶得白色结晶体3-氨基-4-羟基苯甲酸盐酸盐,调pH至2,得3-氨基-4-羟基苯甲酸,纯度（HPLC）≥99.5%,反应总得率为84.3%. 相似文献
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N-(4-氯苯基)-N''-(1,2,4-三氮唑)脲的合成 总被引：1，自引：0，他引：1
冯桂荣 《廊坊师范学院学报》2002,18(4):63-65
以4-氯苯甲酸为原料，经过CURTIUS重排反应制得4-氯苯异氰酸酯，再进一步与3-氨基-1H-1，2，4-三氮唑发生亲核加成反应，合成了目标化合物N-(4-氯苯基）-N'-(1，2，4-三氮唑）脲，其产率为89%。对目标化合物经元素分析、IR和^1HNMR表征，并初步测定了此化合物的植物生长调节活性。 相似文献
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Thirty-six mothers whose children had been abused were interviewed and compared with 36 mothers matched for social class and ethnic background. The abuse group mothers had lower self-esteem than the comparison mothers as judged by their desire that their children should not grow up to be like themselves or their partners. They were also less likely to discuss their problems with other people. They were less likely than the comparison mothers to have been brought up by their own parents. They had significantly more negative feelings than the comparison mothers towards their fathers when they were children and these negative feelings persisted into adult life. It is important that emphasis on treatment programs for these mothers should be placed on building up self-esteem and skills in interpersonal relationships. 相似文献
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哈姆莱特和俄瑞斯忒斯是莎士比亚和萨特这两位戏剧大师创造的杰出的艺术典型，他们不仅身世、遭遇惊人的相似，而且他们所面临的荒诞的生存境遇，以及面对荒诞的思考，孤独感，乃至最终的选择，都极为相似。他们都以自己的行动生动地阐释了存在主义的哲理，因而都成为当之无愧的存在主义英雄。这不仅表明了西方学的一脉相承，而且表现了两个伟大艺术家在反映人类心灵和生存状态方面的感应和相通。 相似文献
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Stephen M. Ritchie Kenneth Tobin Maryam Sandhu Satwant Sandhu Senka Henderson Wolff‐Michael Roth 《科学教学研究杂志》2013,50(2):137-161
Teachers often have difficulty implementing inquiry‐based activities, leading to the arousal of negative emotions. In this multicase study of beginning physics teachers in Australia, we were interested in the extent to which their expectations were realized and how their classroom experiences while implementing extended experimental investigations (EEIs) produced emotional states that mediated their teaching practices. Against rhetoric of fear expressed by their senior colleagues, three of the four teachers were surprised by the positive outcomes from their supervision of EEIs for the first time. Two of these teachers experienced high intensity positive emotions in response to their students' success. When student actions/outcomes did not meet their teachers' expectations, frustration, anger, and disappointment were experienced by the teachers, as predicted by a sociological theory of human emotions (Turner, J. H. (2007). Human emotions: A sociological theory. London, England: Routledge). Over the course of the EEI projects, the teachers' practices changed along with their emotional states and their students' achievements. We account for similarities and differences in the teachers' emotional experiences in terms of context, prior experience, and expectations. The findings from this study provide insights into effective supervision practices that can be used to inform new and experienced teachers alike. © 2012 Wiley Periodicals, Inc. J Res Sci Teach 50:137–161, 2013 相似文献
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卢有泉 《山西大学师范学院学报》2013,(3):58-60
北朝诗歌有自己的源流和生成系统。北朝诗人在传统诗观的导引下,经过长期的创作实践,已确立了自己地域的诗歌创作观念和文学思想,对南北不同地域诗歌风气之差异具有明确的认识。他们站在自己的立场客观地认知南诗,对南诗在技术上的优势比较认同,而对南诗绮丽、细腻的风格并不认同。这样,他们虽学南诗,但仍保留了自己固有的发展道路和品格。 相似文献
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一个合格的教师必须经常学习新的知识,包括学科知识、教学法知识、教育学知识,以及社会道德、文化道德和职业道德,这些学习本身就是研究型教师的重要因素.对于合格的研究型数学教师的界定,应满足:(1)具有较高的道德约束;(2)教师能够根据实际教学情况,发现并解决问题;(3)对数学学科内容应有不同的、发展性的认识;(4)能够与专家进行不同形式的对话和交流. 相似文献
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In changing times for higher education that are dominated by a neoliberal ideology, we set out to uncover how Heads of Departments (HoDs) perceive their role with respect to supporting their staff and their academic freedom. Freedom to pursue academic research is seen as key to the generation of new knowledge yet it is potentially constrained by funding regimes and university accountability systems. As HoDs operate at the interface between university systems and individual academic projects, how they perceive their role can have a profound influence on the working environment of their departmental staff. The research study is located in two successful departments in a research intensive university in England. The study shows that the HoDs were not captured by the neoliberal discourse and aimed to protect their staff so they could ‘get on with their work’. In so doing they interpreted university demands to the best advantage of their departments but were not active in challenging university driven changes, thus raising questions about the effects of accommodating to change, so risking incremental change, and of how less successful departments might be able to protect their staff and their academic freedom. 相似文献
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To encourage increased student attendance and engagement in a third-year economics unit, the curriculum was redesigned to incorporate continuous assessment throughout the semester. A component of group project marks were allocated to peer assessment, in an attempt to address concerns about free-riding colleagues sharing a common mark. This study investigated the consistency of marks awarded to peers within teams, and the acceptance by students of marks awarded by peers. Students were asked to provide ratings and explanatory comments for each of their group peers. Focus groups were conducted to determine students’ acceptance of this strategy. Eighty student ratings were compared to determine consistency of assessment. Within groups, students who received higher marks from their peers generally awarded marks to their peers across a wider range, whereas students who received lower average grades often awarded the same mark to all team members. These results might indicate that students who were attending class regularly and/or contributing at a higher level were more discriminating in the marks awarded to their peers. Similarly, non-contributors (as identified by their peers) assigned the same or similar grades to each of their peers, possibly due to a lack of knowledge about their peers’ contributions. 相似文献
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The present study examined how adolescents' and their romantic partners' romantic working models and relational styles were related to their interactions with each other. Sixty-five couples (M age = 18.1 years) were observed interacting. Romantic working models were assessed in interviews about their romantic experiences; romantic styles were assessed by self-report. Data were analyzed using the Actor Partner Interdependence Model. Working models of romantic relationships, especially girls' models, were predictive of their behavior, the partners' behavior, and the dyads' behavior. Fewer links were found between relational styles and observed behavior. The present study extends past work by showing that representations of romantic relationships influence or are influenced by romantic interactions, even as these representations and relationships are just developing. 相似文献