藻胆体发射终端能量传递过程的研究

利用超快速时间分辨光谱研究了蓝绿藻藻胆体的２个变藻蓝发射终端（ＡＰＢ,ＡＰＩ）单体和三聚体内的能量传递过程,探测到ＡＰＢ和ＡＰＩ单体的两组亚基α＾ＡＰ／β＾ＡＰ和α＾ＡＰＢ／β＾ＡＰ间的能量传递时间常数分别为３０ｐｓ和１９４ｐｓ。ＡＰＢ和ＡＰＩ三聚体所共有的９－３２ｐｓ的短寿命组分来源于同一单体内能量由α＾ＡＰ向βＡＰ的传递过程。     

酞侧基聚芳醚酮的应力松弛与屈服行为的模型解析

根据不同温度下酞侧基聚芳醚酮（ＰＥＫ—Ｃ）的应力松弛曲线及时－温等效原理，得到了ＰＥＫ—Ｃ在任意参考温度下的总曲线．应用Ｋｏｈｌｒａｕｓｃｈ—Ｗｉｌｌｉａｍｓ－Ｗａｔｔｓ（ＫＷＷ）模型定量解释了应力松弛现象的温度依赖性，并通过ＫＷＷ模型建立了应力松弛现象与屈服行为间的相关性．     

Electrical Potential Distribution around a Charged Colloidal Particle: Nonlinear Integral Equation

多电解质溶液中带电胶体粒子的电势分布由球形Ｐｏｉｓｓｏｎ－Ｂｏｌｔｚｍａｎｎ方程（ＰＢＥ）描述．ＰＢＥ是一个非线性的微分方程，且难以求得其解析解．本文采用非线性Ｐ－Ｂ积分方程，计算电势分布的数值解．首先，根据静电场和热力学系统中的物理定理，导出描述电势分布的Ｐ－Ｂ积分方程（ＰＢＩＥ）；其次，用迭代方法求ＰＢＩＥ的数值解．最后，计算了在３－１型电解液中无量纲半径κａ分别为０．１２和０．２２，无量纲表面电势ξ分别为１，２，４，６时球形胶体粒子外部的电势值．为了检验数值解的精度，计算了表面电荷密度，并与Ｌｏｅｂ（１９６１）和Ｏｓｈｉｍａ（１９９５）等人的结果比较，本文结果的相对误差小于１％，优于Ｏｓｈｉｍａ的结果．     

EXTRACTION AND SEPARATION OF RADISH RED PIGMENT FROM A WASTE WATER OF SALTING RADISH BY D61 RESIN

ＥＸＴＲＡＣＴＩＯＮＡＮＤＳＥＰＡＲＡＴＩＯＮＯＦＲＡＤＩＳＨＲＥＤＰＩＧＭＥＮＴＦＲＯＭＡＷＡＳＴＥＷＡＴＥＲＯＦＳＡＬＴＩＮＧＲＡＤＩＳＨＢＹＤ６１ＲＥＳＩＮＺｈｏｕＸｉａｏｈｕａ；ＫａｎｇＪａｎｅ；ＳｈａｎＸｕｅｍｉｎｇ（Ｒｅｓｏｒｓｅｓ＇Ｃｏ...     

高聚物两相体系相行为的流变学研究Ⅰ．均聚物共混体系相行为的研究

本文从流变学角度研究了氯化聚乙烯（ＣＰＥ）／、乙烯－醋酸乙烯酯（ＥＶＡ）共聚物及聚苯乙烯（ＰＳ）／聚乙烯基甲基醚（ＰＶＭＥ）两共混物不稳相分离的动力学过程．发现在相分离早期,共混物的粘度和贮能模量增加,中期及后期,两者逐渐变小．从Ｄｏｉ－Ｅｄｗａｒｄｓ模型出发．考虑到剪切引起的分子形变伴随的流体力学相互作用的变化及其作用下,相互的增长、破裂、旋转等因素,引入Ｄｉｃｋｉｅ有效体积的概念,分析、解释了上述实验现象．但对ＰＳ／ｐｖｍｅ（９０／１０,Ｗｔ％）ＨＣＰＥ／ＥＶＡ（２５／７５,Ｗｔ％）两共混物在相分离后期,粘度有所增长的实验事实,还需深入细致的研究．     

77K下藻胆体模型复合物能量传递过程

利用多变鱼腥藻的藻胆蛋白（ＰＥＣ,ＰＣ和ＡＰＣ）重组出具有完整捕光系统和惟一终端发射基团的ＰＢＳ模型复合物ＰＥＣ／ＰＣ／ＡＰＣ,用超快速时间分辨光谱研究了 ７７Ｋ下重组复合物内能量传递的过程和机制．通过对不同探测波长下复合物激发态衰减曲线的拟合,讨论了不同色团间能量传递关系,尤其是能量在杆与核间的传递关系．探测到复合物杆中两个ＰＥＣ三聚体之间的能量传递时间常数为 ２９ｐｓ; ＰＥＣ六聚体与 ＰＣ六聚体间传递时间常数为 １２ ｐｓ;能量由杆向 ＡＰＣ核传递的时间常数为 ５１ ｐｓ．     

SYNTHESIS OF 1-(TRIPHENYLGERM YLPROPIONO)-4-SUBSTITUTED THIOSEMICARBAZIDES

ＳＹＮＴＨＥＳＩＳＯＦ１－（ＴＲＩＰＨＥＮＹＬＧＥＲＭＹＬＰＲＯＰＩＯＮＯ）－４－ＳＵＢＳＴＩＴＵＴＥＤＴＨＩＯＳＥＭＩＣＡＲＢＡＺＩＤＥＳ￥ＲｕＹｕＣＨＥＮ；ＰｅｎｇＦｕＬｌ（ＩｎｓｔｌｔｕｔｅｏｆＥｌｅｍｅｎｔｏ－ＯｒｇａｎｉｃＣｈｅｍｉｔｒｙ，...     

Keyword Index Vol. 7, 1996

ＫｅｙｗｏｒｄＩｎｄｅｘＶｏｌ．７，１９９６￥／／Ｑ，ａ－Ｄｉｏｘｏ（ｅｓｔｅｒ）ｋｅｔｅｎｅ（－）１０－ＥＰＩ－ａ－－ｃｙｐｅｒｏｎｅｄｉｅｎｅ（７Ｏ３）ｃｙｃｌｅｄｉｔｈｉｏａｃｅｔａｌｓ（６９５）２－ＢｅｎｚｅｎｉｍｉｄａＺｏｌｅｔｈｉｏｌ（９...     

INVESTIGATION OF FRAMEWORK AND EXTRAFRAMEWORK Ti IN TS-1 BY USING RAMAN AND XPS SPECTROSCOPIES

ＩＮＶＥＳＴＩＧＡＴＩＯＮＯＦＦＲＡＭＥＷＯＲＫＡＮＤＥＸＴＲＡＦＲＡＭＥＷＯＲＫＴｉＩＮＴＳ１ＢＹＵＳＩＮＧＲＡＭＡＮＡＮＤＸＰＳＳＰＥＣＴＲＯＳＣＯＰＩＥＳＣｈｅｎｇＳｈｉｂｉａｏ，ＷｕＷｅｉ，ＪｉｎＺｅｍｉｎｇ，ＭｉｎＥｎｚｅ（Ｒｅｓｅａｒ...     

嵌段共聚物微胶束行为的研究Ⅰ．体积排斥色谱法研究聚（苯乙烯－异成二烯）二嵌段共聚物在选择性溶剂中微胶束的形成过程

采用体积排斥色谱研究聚（苯乙烯－异成二烯）二嵌段共聚物在选择性溶剂－二氧六环／甲醇混合体系中以ＰＩ为核ＰＳ为壳的微胶柬形成过程，以及在正庚烷／乙酸异戊酯混合体系中以ＰＳ为核ＰＩ为壳的微胶束形成过程。讨论了温度、混合溶剂的配比和共聚物分子量对微胶束形成的影响。根据体积排斥色谱图估算了形成微胶束时的表观缔合能和微胶束的表观缔合数．     

2,4-二硝基氯苯碱性水解胶团催化的活化能

研究了阳离子表面活性剂氯化十六烷基吡啶(CPC)和十六烷基三甲基氯化铵(CTAC)胶团对2,4-二硝基氯苯(DNCB)碱性水解的催化作用和小分子极性有机物丁醇的加入对该反应的影响,计算了反应活化能.结果表明:(1)CPC和CTAC胶团对DNCB碱性水解都有明显的催化作用;(2)加入少量叔丁醇略有利于提高催化效果;(3)在CPC和CTAC胶团溶液中DNCB碱性水解反应的活化能约为49kJ/mol,比纯水中的91kJ/mol低得多,说明反应机制可能存在差异.     

Counterion specificity of the micelle surface and its implications on micellar catalysis

Dodecyltrimethylammonium bromide — Dodecyltrimethyl-ammonium hydroxide — water mixtures were studied with ion-selective electrodes, and the aggregation behavior, degree of ionization of the micelles and the distribution constants of bromide and hydroxide ions between water and micelles were found, showing that some suppositions about the interpretation of micellar catalysis are incorrect, and these interpretations must be revised. The results support the mass action model for the theoretical treatment of micellar catalysis.     

Micellar effects upon electron transfer from ferrocenes

The oxidations of ferrocene (FcH) and n-butylferrocene (FcBu) by ferric salts (nitrate or bromide) are strongly inhibited by aqueous cetyltrimethylammonium bromide and nitrate (CTABr and CTANO₃, respectively). The kinetics of inhibition fit a model in which the substrates are distributed between water, and the micelles and binding constants K_s to the micelle can be estimated. The oxidations are strongly catalyzed by micelles of sodium lauryl sulfate (NaLS), and the kinetics can be fitted to a model in which the reaction rate depends upon the concentration of both reactants in the micellar pseudophase and the rate constants in that pseudophase, which for both substrates are very similar to those in water. Some added salts reduce the micellar catalysis by excluding ferric ions from the micelle. The oxidations of FcH and FcBu by ferricyanide ions are too fast to be followed in water, but they are inhibited by anionic micelles of NaLS. By analyzing the rate surfactant profiles using independently measured values of K_s the second-order rate constants in water have been estimated.     

Kinetics of alkaline fading of methyl violet in micellar solutions of surfactants: Comparing Piszkiewicz's,Berezin's,and pseudophase ion-exchange models

The micellar effect of surfactants of various types on the rate of the reaction between methyl violet and hydroxide ion is studied. The absorption spectra show that the cation of methyl violet is bound by micelles of all types at proper concentrations of surfactants. The observed rate constant in micellar systems containing nonionic Brij-35, zwitterionic 3-(dimethyldodecylammonio)-propanesulfonate, cationic cetyltrimethylammonium bromide and hydroxide surfactants is higher, whereas in solutions of the anionic surfactant sodium dodecylsulfate is lower than that one in the surfactant-free system. Piszkiewicz's, Berezin's, and pseudophase ion-exchange models of the kinetic micellar effect are used for the treatment of the dependences of the above-mentioned constants on the surfactant concentration. The values of the corresponding kinetic parameters are compared and discussed. The influence of nonionic, zwitterionic, and anionic micelles on the reaction rate is discussed on the basis of medium and concentration kinetic effects. The character of the cationic micelles effect is somewhat paradoxical. Although the observed pseudo–first-order reaction rate constant substantially increases in the presence of such micelles, the second order-rate constant in these micelles is lower than the corresponding value in surfactant-free aqueous solution. As a possible explanation, the decrease in the reactivity of the HO^– ions is proposed, owing to their electrostatic association with the cationic headgroups (“diverting effect”).     

Kinetic and Solubility Studies in Zwitterionic Surfactant Solutions

The zwitterionic micelles formed with two carboxybetaines and fivesulfobetaines have been investigated by micellar catalysis and dye solubility studieswith the probe Ni²⁺/PADA complexation reaction and the dye,pyridine-2-azo-p-dimethylaniline (PADA). Catalysis occurs with the carboxybetaines, butinhibition of the probe reaction arises with all of the sulfobetaines. Bothreactants enter carboxybetaine micelles, but Ni²⁺ ions are not appreciablyadsorbed by sulfobetaine micelles.     

Micellar effects of a triazole-based cationic gemini surfactant on the rate of a nucleophilic aromatic substitution reaction

The reaction between 2,4-dinitrochlorobenzene (DNCB) and hydroxide ion was studied spectrophotometrically at 25 °C in micelles of a triazole-based cationic gemini surfactant 18-triazole-18 or micelles of the conventional cationic surfactant CTAB. Both CTAB and 18-triazole-18 accelerated this nucleophilic aromatic substitution reaction. The binding constant of the substrate to the micelle, K _S, for 18-triazole-18 (K _S=335 M⁻¹) was found to be much larger than that for CTAB (85 M⁻¹) by fitting the kinetic results with pseudophase ion-exchange (PIE) model, which suggests that DNCB binds with gemini micelles more easily than it does with CTAB micelles. It was also found that 18-triazole-18 catalytic system was in accordance with PIE model at surfactant concentrations below ca. 0.5 mM, above which the increase of viscosity and the change of micelle size with increased surfactant concentration may remarkably influence the reaction. This was quite different from the reaction catalyzed by micelles of the conventional surfactant CTAB.     

Numerical Calculation of the Electrostatic Potential Around an Ionic Micelle with Counter Ion Binding

A numerical solution of the nonlinear Poisson-Boltzmann equation (PBE) is presented for a system of spherical micelles with counterfoil binding. The approach investigates the following effects on ion micelle interactions, (i) total surface charge, (ii) competitions of different counter ions on micellar surfaces and (iii) surface potential determination. The theory is applied to interpret the ion activities in micellar solution as measured by ion-selective electrodes.     

Micellar Catalysis of Composite Reactions—The Effect of SDS Micelles and Premicelles on the Alkaline Fading of Crystal Violet and Malachite Green

ABSTRACT

The effect of SDS micelles and premicelles on the reversible alkaline fading reactions of crystal violet and malachite green were studied. Micellar and premicellar catalysis models for 1-1 type reversible reactions were proposed. The rate constants of forward and backward reactions and equilibrium constants of these reversible alkaline fading reactions in SDS micellar solutions were obtained from a micellar catalytic model. Under the premicellar condition the average number of SDS molecules per substrate molecule with n surfactant molecules was obtained from a premicellar catalytic model. The results indicated that both SDS micelles and premicelles exhibited an inhibiting effect on the forward reaction, while they exhibited an accelerating effect on the backward reaction. These results can reasonably be accounted for in terms of electrostatic interactions.     

THE EFFECT OF SURFACTANT MICELLES ON THE ALKALINE HYDROLYSIS OF DIMETHYLFORMAMIDE

The alkaline hydrolysis of dimethylformamide has been studied at 40'C in micellar solutions of single surfactant (CTAB. SDS. Brij 35) with the analog thermoanalytical curve method of thermokinetics. A kinetic equation of micellar catalysis under the condition of highter reactant concentration than micellar concentration ([S]>[M]) has been derived from the pseudophase model of micellar catalysis and some relative assumptions, The kinetic parameters. k_m, k_2mand the association constant of reactant with micelle K₁, have been calculated in this way. the results indicate that these surfactant micelles exhibit catalytic effect on the reaction. This is attributed to the micropolarity and local concentration effect of micelles.