硝基苯化合物对聚对苯撑乙炔基咔唑荧光淬灭性能研究

以2,5-二甲氧基对苯二乙炔和3,6-二碘-9-戊基咔唑为单体,采用Sonogashira偶合反应合成了含有咔唑基团的聚对苯撑乙炔基咔唑(P).硝基苯衍生物对该聚合物的荧光淬灭实验结果表明,当对位取代基团不同时,取代基的推电子能力越强对聚合物P的淬灭效率越高;对相同取代基的淬灭剂而言,邻、对位取代时的淬灭效率明显高于间位取代化合物.淬灭剂是与P通过形成电荷转移络合物而使处于激发态的P分子链发生能量转移的,淬灭剂对P荧光的淬灭效率随其浓度的增大而非线性升高.     

Solvent effects on photophysical properties of copper and zinc porphyrins

The photophysics of Zn（tetraphenylporphyrin,TPP）, Zn（tetra-2,4,6-trimethylphenyl porphyrin, TMP）, Zn （tetra-（o-dichlorophenyl） porphyrin, TPPCI8）, Cu（tetraphenylporphyrin,TPP）, Cu（tetra-2,4,6-trimethyl- phenyl porphyrin,TMP）, and Cu（tetra-（o-dichlorophenyl） porphyrin, TPPCIE, TPPCI8） in several solvents have been investigated on steady state and time-resolved spectroscopy. The Cu（TPPCI8 ） is normal and shows no evidence of CT transition in the visible or near UV regions in nonpolar solvent. However, Cu（TPPCI8）shows a blue shift in the absorption spectrum and intramolecular CT bands at absorption spectra in polar solvent, which shows a fluorescence maximum emission at 650 nm and 8.4 ns lifetime. The reason can be attributed to two points. Firstly, the increase of solvent polarity can enlarge outer reorganisational energy, which is favorable to reduce the activation free energy of charger-transfer transition based on Marcus theory of electron transfer. Moreover, the internal heavy-atom effect on Cu（TPPCIE） is encouraging to stabilize the 2T1 state also, which increases the possibility of population to CT band from 2T1 state. This result is in accord with an earlier estimate of a 10 ns lifetime and CT absorption at 640 nm bands for the CT state of Cu （11） octethylporphyrins. Other possible reasons arousing unusual fluorescence like H-bonding, axial ligands, molecular aggregation are excluded.     

Three-dimensional fluorescence spectral characteristics of dissolved organic carbon in cave drip waters and their responses to environment changes: Four cave systems as an example in Guizhou Province,China

Understanding the responses of fluorescence spectral characteristics of cave drip waters to modern environment and climate changes is key to the reconstructions of environmental and climatic changes using fluorescence spectral characteristics of speleothems. The fluorescence spectral characteristics of dissolved organic carbon （DOC） in four active cave systems were analyzed with a three-dimensional （3D） fluorescence spectral analysis method. We found that the fluorescence types of DOC were mainly of fulvic-like and protein-like fluorescences, both in soil waters and cave drip waters. The intensity of fulvic-like fluorescence was positively correlated with the concentrations of DOC, suggesting that the DOC of cave drip waters was derived from the overlying soil layer of a cave system. Compared with the other cave systems, the variation range of the excitation and emission wavelengths for fulvic-like fluorescence of cave drip waters in Liangfeng cave system that had forest vegetation was smaller and the excitation wavelength was longer, while its fluorescence intensity varied significantly. By contrast, the excitation and emission wavelengths and fluorescence intensity for that in Jiangjun cave system that had a scrub and tussock vegetation showed the most significant variation, while its excitation wavelength was shorter. This implies that the variation of vegetation overlying a cave appears to be a factor affecting the fluorescence spectral characteristics of cave drip waters.     

摘花序和打顶对怀牛膝叶绿素荧光特性和品质的影响

以现蕾期怀牛膝为材料,研究了摘除全部花序、打顶等处理对怀牛膝生育性状特征、叶绿素含量、叶绿素荧光特性、根部产量和多糖含量的影响.结果表明,现蕾期摘除全部花序后,怀牛膝植株生长健壮,叶绿素含量升高,Fw/Fo,Fv/Fm和ETR升高.潜在光合性能增强,根部产量和多糖含量升高;打顶后植株生殖生长旺盛,根部增产效果不明显.     

邻氯酚红与牛血清白蛋白相互作用的荧光光谱研究

应用荧光光谱法研究了三苯甲烷类染料邻氯酚红与牛血清白蛋白(BSA)的相互作用.研究表明,邻氯酚红能与牛血清白蛋白形成稳定的络合物从而引起BSA的荧光猝灭,疏水作用是结合反应的主要作用力,二者的结合常数为1.2002×106L.mol-1,结合位点数n=1.2586(17℃时),能量转移效率为E=0.3086,染料距色氨酸残基最短距离为r=4.92nm.同时考察了邻氯酚红的加入对BSA构象的影响.     

多元校正荧光法同时测定α-萘乙酸和吲哚-3-乙酸

在紫外光激发下,植物生长调节剂萘乙酸（NAA）和吲哚-3-乙酸（IAA）均能发射荧光,最大激发／发射波长分别为λex／em=291／337nm,λex／em=287／371nm。研究了酸度、光照时间、温度及共存物对荧光强度的影响。建立了多元校正不经分离同时测定NAA和IAA两组分的新方法。NAA和IAA线性范围分别是6．44×10^-8-29×10^-6mol·L^-1,1．94×10^-8-3．88×10^-7mol·L^-1;最低检测限为2．10×10^-8mol·L^-1,1．08×10^-8mol·L^-1。该法对两组分合成样及强化水样均有较好的解析能力,回收率在92％-103％之间。     

一类特殊整数规划问题的DNA计算

通过22种荧光标记DNA链的办法,在基于表面方式的实验环境中,将变量用变异的二进制变量组来表示,提出一种基于DNA计算的特殊整数规划问题的求解算法.算法通过将上述问题转化为特殊的-1-0-1规划问题,解决了运筹学中特殊的整数规划问题,并为最终解决一般的整数规划问题奠定了基础.     

铬原子束激光感生荧光强度的理论和实验

采用铬原子束激光感生荧光激光稳频技术解决铬原子光刻实验中激光频率随时间漂移的问题.从理论和实验两个方面对铬原子束激光感生荧光强度随激光功率和坩埚温度的变化情况进行了研究.结果显示,在坩埚温度一定的情况下,由于铬原子的饱和效应,当激光功率增大到6 mW左右时,荧光斑点的中心强度会达到饱和然后随激光功率的增加变化不大.另外,随着激光功率的增加,荧光斑点轮廓曲线的半高宽在变大的同时,对比度减小.在激光功率一定的情况下,由于铬原子喷射的个数与坩埚温度成正比,荧光斑点的中心强度随坩埚温度的增加而增加,并且不出现饱和效应;随着坩埚温度的升高,荧光斑点轮廓曲线的半高宽基本不变,而对比度增大.这些变化趋势和理论结果符合地很好.     

温度、酸碱度和变性剂对黄花石蒜凝集素活性和构象的影响

采用荧光光谱研究了不同温度、pH和变性剂对黄花石蒜凝集素（Lycoris aurea agglutinin,简称LAA）凝血活性和分子构象的变化关系,结果表明：LAA具有较强的温度和酸碱度的耐受性,经过3种变性剂的处理都能使LAA分子构象发生不同程度的变化并导致活性的丧失,浓度为6 mol/L的盐酸胍和脲,20 mmol/L的SDS可以使LAA完全丧失凝血活性,荧光光谱的变化表明了这种变性过程具有阶段性.     

新型含氟细胞钙离子荧光探针Fluo-3F的合成

目的设计并合成新型含氟荧光素类细胞钙离子荧光探针Fluo-3F。方法以5-氟邻硝基苯酚为起始原料,5步反应得到中间体BAPTA-F-CHO,再与4-氯间苯二酚缩合。结果新型含氟荧光素类钙离的结构经核磁共振光谱,红外光谱,质谱,元素分析得到证实。结论合成的新型含氟荧光素类钙离子荧光探针Fluo-3F荧光性能优异,为合成新型钙离子荧光探针提供了新的思路。