红藻条斑紫菜R—藻红蛋白中的能量传递过程

本文通过对条斑紫菜Ｒ－ＰＥ（藻红蛋白）及其α、β、２亚基的吸收光谱和荧光光谱进行计算机解叠，研究了Ｒ－ＰＥ内发色团之间的能量传递过程，并对Ｒ－ＰＥ及亚基门的各发色团进行了“Ｓ”和“ｆ”型的指认。发现在亚基中为“ｆ”型的发色团在Ｒ－ＰＥ中起着“ｓ”型发色团的作用，且将能量传递给量最后的“ｆ”型发色团。荣光激发偏振光谱进一步证明了Ｒ－ＰＥ内的能量转移过程与计算机解叠的结果一致。     

多变鱼腥藻藻胆蛋白共价复合物的合成及其分子内能量传递

利用双功能基偶联剂３－（２－吡啶联巯基）丙酸Ｎ－羟基琥珀酰亚胺酯（ＳＰＤＰ）合成了两个藻胆蛋白复合物,藻红蓝蛋白－变藻蓝蛋白复合物ＰＥＣ－ＡＰＣ和藻红蓝蛋白－藻蓝蛋白复合物ＰＥＣ－ＰＣ．利用吸收光谱和荧光光谱证明了藻胆蛋白构型与构象在反应后得到保持．通过荧光光谱观察到能量传递现象．计算出复合物ＰＥＣ－ＡＰＣ的分子内能量传递效率约为９０％．复合物ＰＥＣ－ＰＣ中藻红蓝蛋白ＰＥＣ的荧光寿命比ＰＥＣ本身的寿命大大缩短,证明存在分子内能量传递．二硫苏糖醇（ＤＴＴ）还原二硫桥键后能量传递被阻断．这进一步证明复合物合成成功及分子内能量传递．     

螺旋藻中藻蓝素的提取研究

从螺旋藻中提取藻胆蛋白,用甲醇解离其硫醚键得藻蓝素。其最佳解离条件是：温度为４０℃,解离时间为２４ｈ,Ｖ（甲醇）∶ｍ （藻胆蛋白） ＝２００∶１ 。提取率可达１－５％ ,产物的ＵＶ,ＩＲ和文献相符。藻蓝素发色团在酸性溶液中呈比较扩展型,而在中性溶液中呈比较闭合的结构。     

藻胆蛋白免疫荧光法的初步探索

采用CNBr活化的琼脂糖凝胶小珠作为固相载体,应用藻胆蛋白荧光标记物对血清可溶性抗原检测作了初步的探索. 结果表明, 藻胆蛋白免疫荧光法用于可溶性抗原检测不但可行,而且具有荧光强度高、可长期保存且无明显衰减等特点.     

B-藻红蛋白在表面活性剂中的光谱性质

对标题化合物在3种不同类型的表面活性剂中的可见吸收光谱进行了研究.实验条件下,阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)使B-藻红蛋白的最大吸收峰由545 nm蓝移至506 nm,随CTAB浓度增加,最大吸收值显著下降.阴离子表面活性剂十二烷基硫酸钠(SDS)在低浓度时对B-藻红蛋白的特征吸收峰形影响不大,当SDS的浓度2.0×10-3mol/L时,B-PE在564 nm的吸收峰消失.非离子表面活性剂Triton X-100对B-藻红蛋白的吸收峰形没有产生明显影响,并使吸收峰强度均有所增加.还初步探讨了B-藻红蛋白在3种表面活性剂中光谱变化的机理.     

藻蓝蛋白对Au（Ⅲ）原位还原与纳米Au（0）形成动态过程的谱学研究

在4℃、避光条件下,将藻蓝蛋白（PC）与AuCl3作用,通过UV、FS、FT-IR等谱学方法研究了PC与Au（Ⅲ）作用的动态过程,结果显示：PC在615nm的特征吸收峰强度明显减弱,并随Au（Ⅲ）浓度增加和时间延长单调降低;PC的荧光发射峰和荧光激发峰也均呈现衰减趋势.同时通过TEM观察到纳米Au（0）粒子形成,纳米金基本呈球形,有较窄的分布尺寸,粒径在20 nm左右,均匀地分散于PC中,这是PC原位还原Au（Ⅲ）所形成的.     

藻蓝蛋白对Au(III)原位还原与纳米Au(0)形成动态过程的谱学研究

在4℃、避光条件下,将藻蓝蛋白(PC)与AuCl3作用,通过UV、FS、FT-IR等谱学方法研究了PC与Au(III)作用的动态过程,结果显示:PC在615nm的特征吸收峰强度明显减弱,并随Au(III)浓度增加和时间延长单调降低;PC的荧光发射峰和荧光激发峰也均呈现衰减趋势.同时通过TEM观察到纳米Au(0)粒子形成,纳米金基本呈球形,有较窄的分布尺寸,粒径在20 nm左右,均匀地分散于PC中,这是PC原位还原Au(III)所形成的.     

B-藻红蛋白多层复合薄膜的静电组装及其光谱特性

B-藻红蛋白是一种理想的生物光电材料.利用静电组装技术制备了聚二甲基二烯丙基氯化铵(PDDA)与B-藻红蛋白组装的多层复合薄膜.对薄膜的可见吸收光谱和荧光光谱进行了分析,结果表明:与B-藻红蛋白在溶液中的光谱特征相比,B-藻红蛋白在薄膜上的最大吸收峰由545 nm红移至553 nm,并在573 nm处产生了延迟荧光现象,且薄膜的最大吸光度和光致发射强度均与组装层数呈线性递增关系.随着薄膜组装层数的增加,倒置荧光显微镜能很好地观察到B-藻红蛋白在薄膜上出现明显的聚集体.     

两种不同光谱类型的R-藻红蛋白的荧光性质研究

红藻中的R-藻红蛋白(R-PE)依照其吸收光谱可分为两种不同的光谱类型,即“双峰型”和“三峰型”.本文通过对不同pH条件下的R-PE的荧光光谱及荧光寿命的研究,发现“三峰型”R-PE的pH稳定范围较“双峰型”R-PE大.在R-PE浓度对荧光光谱的影响实验中,随着蛋白浓度的增加,荧光峰位置逐渐红移。荧光寿命逐渐增大,荧光强度先行增加而后减弱.用碘离子对其荧光进行猝灭,随着碘离子浓度的增大,荧光强度逐渐降低,荧光寿命逐渐缩短,并服从Stem-Volmer规则.     

蒽－对二氰基乙烯基苯激基复合物的形成与能量传递

本文设计合成了三个以不同链长相连接的蒽－对二氰基乙烯基苯（Ａｎ－ＤＣＶＢ）化合物。利用吸收光谱，荧光光谱，激光闪光光解和单光子计数器等证实Ａｎ－ＤＣＶＢ受光激发，发生分子内电子转移，生成激基复合物且发现有三重态能量传递，描述了分子内电子转移的主要途径，研究并探讨了Ａｎ－ＤＣＶＢ的三种不同连接链长对分子构象，激基复合物的形成以及三重态能量传递的影响。     

一类以双酚A为连接链的电子给体—受体体系的合成及分子内电子转移反应研究

本文合成了一类以９，１０－二甲氧基蒽为给体，双酚Ａ为连接链连接不同受体的电子给体受体新体系，通过稳态荧光光谱及时间分辨荧光光谱研究了它们的光致电子转移反应，并通过测定氧化还原电位，计算出各电子给个受体体系电子转移反应的自由能变化。结果表明，在这一类体系中，光致电子转移速率常数与自由能变化关系符合Ｒｅｈｍ－Ｗｅｌｌｅｒ关系式。     

Nucleophilic substitution reactions on 3-bromo- and 3-nitrobenzanthrones

Nucleophilic substitution reactions of 3-bromobenzanthrone and 3-nitrobenzanthrone have been studied. Reaction of 3-bromobenzanthrone with different arylamines gave rise to 6-arylamino-3-bromobenzanthrones. Anomalous behaviour was observed with 2-aminobenzothiazole, when the bromine atom underwent displacement, and with thiourea, when 3-mercaptobenzanthrone was obtained. Reactions of 3-nitrobenzanthrone, on the other hand, gave rise to 4-substituted amino derivatives.     

NiNb2O6半导体电极的能级结构和腐蚀机理研究

本文通过测量伏安特性和光谱响应了被还原的ｎ型ｎ型ＮｉＮｂ２Ｏ６半导体晶电极的光电化学物质及其能级结果。观察到两个吸收带，强者在３．２４ｅＶ，对应于氧－铌跃廷；弱者在１．７５ｅＶ，在可见光区，对应于镍－铌跃迁，探讨了阳极暗腐蚀、光腐蚀和水的光电解机理，缓出了ＮｉＮｂ２Ｏ６的电子能级和主主要的裂解能级。     

几种荧光有机化合物的电荷转移光谱

几种荧光有机化合物的电荷转移光谱英柏宁，宦萍，涂敬仁（中山大学化学系，广州５１０２７５）关键词荧光有机化合物，电荷转移络合物，电离势具有荧光的有机化合物是一些具有多个共轭双键，分子呈平面结构，有大的电子离域体系的化合物。这类光致发光的化合物中，一般含...     

New daylight fluorescent pigments

The synthesis and properties of a series of plastosoluble daylight fluorescent pigments based on benzanthrone, 1-azabenzanthrone, 14H-[2,1,9-mna]thioxanthene-14-one and its 5-aza analogue are reported.     

Error analysis and modelling of non-linear stress-strain behaviour in measuring dynamic mechanical properties of polymers with the Rheovibron

The Rheovibron is widely used for measuring the dynamic mechanical properties of polymers. Poor reproducibility and data variation which have been considered inherent to the Rheovibron operation necessitate both instrument modifications and modelling of the instrument operation for quantitative interpretation of the experimental data. The instrument modifications that have been made in this study include electronic modifications, a new clamp design that eliminates sample mounting and slippage problems, and the design of an environmental chamber, which, along with a nitrogen purge, eliminates moisture condensation on the sample at low temperatures. A previously-developed mathematical model for the instrument has also been extended to account for the effect of the static stress and the stress rate imposed on the sample during measurement. Based on a simple constitutive relation for non-linear stress-strain behaviour of polymers, this model has been applied to a number of polymeric materials including polyethylene, polyimide, poly (ethylene terephthalate), and polypropylene, among others. The instrument modifications and modelling of the influence of static stress and the stress rate imposed on the sample during dynamic mechanical testing allows for reproducible (within 5%) and accurate use of the Rheovibron.     

Molecular motion in melt samples of poly(propylene glycol) studied using dielectric and Kerr effect relaxation techniques

Dielectric relaxation times and electro-optical Kerr-effect relaxation times have been measured for melt samples of pure poly(propylene glycol) of nominal molecular weight 1025, 2025 and 4000, over the temperature range 209K–255K. Kerr-effect relaxation curves were analysed in terms of two main components: a ‘fast’ primary process (A), associated with a negative optical birefringence; and a ‘slow’ secondary process (B), associated with a positive optical birefringence. Measurement of dielectric loss at different frequencies for poly(propylene glycol) of molecular weight 2025 and 4000 indicated two main relaxation processes: a ‘fast’ process (the normal α-process), which carried with it most of the dielectric loss; and a ‘slow’ secondary process of much smaller amplitude. The close correspondence between dielectric and Kerr-effect relaxation times, for the primary and secondary relaxation processes, indicated that these techniques are probing effectively different aspects of the same molecular motion. Dielectric and Kerr-effect relaxation times for the secondary process depended greatly on the molecular weight of the polymer and were compared with the predictions of the models for the reptational motions of chains in the bulk polymer, as proposed by De Gennes and by Doi and Edwards.     

Mechanism of the emulsion polymerization of methyl acrylate: 1. Initiation

The emulsion polymerization of methyl acrylate (MA) has been carried out under two different experimental conditions so as to establish the mode of chain initiation. In the first system, the initiator was Fenton's reagent (FeSO₄ and H₂O₂ redox pair) in acid solution at 20°C in the presence of a cationic detergent, cetyltrimethyl — ammonium bromide (CTAB), while in the second system the initiator was potassium persulphate (K₂S₂O₈) at 50°C in the presence of an anionic detergent, sodium lauryl sulphate (NaLS). The polymerization was followed by the conventional dilatometric and gravimetric methods. Initial rates were determined by keeping the conversion below 10% and by plotting the (yield/time) versus time, and extrapolating the straight line to zero time. It was found that in either case, Initial rate (v) ∝ (Initiator)^0.50 while the viscosity average molecular weight ($\text{M}{}_{\mathrm{v}}$) of the polymers up to 20% conversion was found to be approximately inversely proportional to the square root of the initiator concentration (I), i.e. $\text{(}\text{M}{}_{\mathrm{v}}\text{) ∝ (I)}{}^{\mathrm{?0.50}}$. The rate of polymerization up to 10% conversion was found to be approximately linear with the monomer concentration (from 0.5 to 5.0—, v/v) in the presence of detergents (above CMC) [critical monomer concentration] under the experimental conditions. Since the kinetics of the emulsion polymerization of MA at zero conversion are the same as that of the homogeneous polymerization of MA initiated by the free radicals, it is suggested that the initiation of the emulsion polymerization of MA takes place in the aqueous phase with little or no initiation in the detergent micelles containing monomer. If the polymerization is carried out within the solubility range of MA in the aqueous phase, then the initiation will take place entirely in the aqueous phase. Assuming homogeneous polymerization at zero conversion, the value of the termination rate constant (k_t) has been extracted from the experimental data at different initiator efficiencies.     

E.s.r. study of annealing and melting effects on the molecular motion of spin trapped chain-end radicals located on the polyethylene surface

E.s.r. spectra of chain-end spin labels on the surface of polyethylene powder were obtained for high and low density polyethylene samples at various stages of heat treatment process. The subsequent crystalline structures of the samples were examined with wide angle and small angle X-ray diffraction spectra. The effects of annealing on the motion of the labels were dependent on annealing temperature and the type of the samples. Higher temperature annealing decreased the rotational correlation times (τ_c) and their activation energy in high density polyethylene but did not affect those of low density polyethylene. Melting decreases the values of τ_c and ΔE for both high an low density polyethylene samples. The cause of these decreases were attributed to the changing of the sites of the chain-end labels. The motion of the labels appeared to be influenced by the local segmental motion of the polymer main chains.