排序方式: 共有18条查询结果,搜索用时 15 毫秒
11.
12.
以苯甲酸正丁酯的合成为例,介绍了有机化学实验"学、教、做、评"四位一体的教学模式。以导学、助学、促学、先学后教等方式促进学生自主学习的积极性;采用以问题为中心的教学方法,确立了以教师为主导、学生为主体的师生关系,充分发挥了学生的主观能动性;以开放性实验代替传统实验,充分培养了学生的实验技能和科学素养;对实验成绩进行综合立体评价,体现了评价的客观性和真实性。实践表明"四位一体"的教学模式不仅能够充分调动学生的主观能动性,培养学生的实验技能和兴趣,而且能有效地提高实验教学质量。 相似文献
13.
α-含氧取代酞菁的聚集性质研究 总被引:2,自引:0,他引:2
以3-硝基邻苯二腈为原料分别与苯酚和甲醇反应合成3-苯氧基邻苯二腈和3-甲氧基邻苯二腈, 这些α-取代的邻苯二腈以二甲氨基乙醇为溶剂, 在有无醋酸锌条件下环合, 分别形成α-四苯氧基锌酞菁、α-四苯氧基无金属酞菁、α-四甲氧基锌酞菁、α-四甲氧基无金属酞菁, 对产物结构进行了表征. 光谱分析结果表明, 此类锌酞菁在氯仿等非配位溶剂中能自发形成J型聚集体, 其Q带出现一个红移吸收带, 经UV-Vis光谱、荧光光谱及MALDI-TOF质谱分析表明, 该聚集体的形成机理为基于酞菁分子间的锌-氧自配位相互作用. 相似文献
14.
本文通过重氮化反应设计、合成了鲁米诺偶联的氨基锌酞菁,对其电子吸收光谱和荧光光谱性质进行了研究,结果表明该分子激发单重态可能以振动驰豫的方式使大部分能量耗散,鲁米诺偶联前后,氨基取代锌酞菁的荧光光谱有明显差别,为进一步开发酞菁类荧光光存储材料提供了理论依据. 相似文献
15.
克酮酸染料是一类新型的近红外吸收染料,由于具有良好的光热稳定性和荧光性能,因而在光记录与存储等领域有着潜在的应用价值.本文利用简并四波混频技术,在近红外区不同吸收波长,在脉宽为130 fs条件下研究了一种吲哚克酮酸染料在溶液和薄膜中的三阶非线性光学性质.该克酮酸染料在773 nm,四氢呋喃溶液中的共振三阶超分子极化率γ为5.3×10-29esu,在薄膜中的共振三阶非线性极化率χ(3)值达到10-8esu数量级.同时,对于三阶非线性光学响应及其动力学机制也进行了研究和探讨. 相似文献
16.
Resonant Third-Order Optical Nonlinearities of Poly(methyl methacrylate) Films Containing J-Like Aggregates of a Thiadicarbocyanine Dye
下载免费PDF全文
![点击此处可从《中国物理快报》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The third-order optical nonlinearities and responses of poly(methyl methacrylate) (PMMA) coating films containing J-like aggregates of a thiadicarbocyanine dye, 3,3'-diethyl-2,2'-thiadicarbocyanine iodide (DTDC1), are measured by degenerate four-wave mixing (DFWM) technique under resonant conditions. The temporal profiles of the DFWM signal of PMMA coating films containing J-like aggregates of DTDC1 are found to consist of three components: i.e., the coherent instantaneous nonlinear response (electronic response) and the two slow responses uqth decay time constants of about 0.8ps and about 7.0ps. The electronic component of the effective third-order nonlinear susceptibility, χc^(3), of one of the present films is as high as about 2.1×10^-8 esu, and the figure of merit of third-order nonlinearity F (F=χ^(3)/α) is evaluated to be about 1.9 ×10^-13 esu cm at 850nm. 相似文献
17.
Nonlinear Optical Properties of Novel Polymeric Rare Earth Phthalocyanine Studied Using Picosecond Z-Scan Technique
下载免费PDF全文
![点击此处可从《中国物理快报》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Three novel tri-dimensional phthalocyanine polymers, with lanthanum (LaPPc), gadolinium (GdPPc) and ytterbium (YbPPc) as centric atoms, have been synthesized from a tetranuclear phthalonitrile. Third-order optical nonlinearities of these compounds in DMF solution are measured by a picosecond Z-sacn technique at 532 nm. It is found that all the compounds show reverse saturation absorption and nonlinear self-focus refraction effect. The second-order molecular hyperpolarizabilities are calculated to be 1.82×10^-23, 1.48×10^-23 and 1.45×10^-23 esu for LaPPc, GdPPc and YbPPc, respectively. The differences among their nonlinear optical properties are attributed to the special tri-dimensional structure and the variation in rare earth atoms. 相似文献