Pitzer model parameters for sparingly soluble salts from solubility measurements. The systems TlCl+SrCl2+H2O and TlCl+BaCl2+H2O at 25°C

The solubility of thallium(I) chloride has been determined in aqueous solutions of strontium chloride and barium chloride at concentrations up to 1.5 mol kg^–1. The data were analyzed using Pitzer's equations without making explicit assumption of association to ion pairs by assuming =3 instead of =2, with the ⁽¹⁾ term for TlCl being equivalent to the ⁽²⁾ term for 2-2 electrolytes. Best values of ⁽⁰⁾ and ⁽¹⁾ for TlCl are recommended together with K _s , the activity solubility product. These were used to fit the present solubility data and derive the Pitzer model mixture parameters relevant to the systems, _fTIN and _fTINCl (N=Sr, Ba). Mixture parameters for TlCl+MCl+H₂O systems are also derived to complete the parameter base. The fit of the experimental data was found to be worse when higher-order terms for asymmetrical mixing were included in the analysis. Activity coefficients for thallium(I) chloride in the mixtures are derived.     

固定波长同步荧光光谱参数的理论计算

基于荧光激发光谱和发射光谱对波长呈高斯分布的设定,本文推导出固定波长同步荧光光谱峰峰值位置、相对强度和半峰宽度等3个主要光谱参数的理论计算式。所提出的计算式应用于若干荧光物质光谱参数的计算,并和实测值、文献计算值作了对照。结果表明,和文献计算方法相比,本法与所研究物质的实际光谱参数较为接近,可为固定波长同步荧光光谱参数的理论计算提供一有效方法。     

甘氨酸与氯化碱金属在水中的焓相互作用参数

氨基酸在混合溶液中的热力学性质及相互作用的研究不论对溶液化学还是生命科学都是十分重要的．对此国内已有不少的研究h，’1．利用偿效应的方法研究氨基酸与电解质间的相互作用是很有效的卜一句，但大多数的工作都是在低浓度下研究一个氨基酸分子和一个电解质离子对间的相互作用烩．本文测定了甘氨酸在水中和在LICI、NaCI、KCI的水溶液中的溶解偿，计算出甘氨酸与各个公在水中的偿对相互作用参数和三相互作用参数，并由此讨论了甘氨酸与这些盐的对分子相互作用和三分子相互作用．1实验部分试剂：甘氨酸为ARfa，K甲醇一水重结晶．LI…     

Solvent Effects on the Structure-Activity Relationship of Pharmacological Active 3-Substituted-5,5-Diphenylhydantoins

Absorption spectra of eight 3-substituted-5,5-diphenylhydantoins have been recorded in fourteen solvents in the range 200–400 nm. The effect of solvent dipolarity/polarizability and solvent/solute hydrogen bonding interactions are analyzed by means of the linear solvation energy relationship (LSER) concept proposed by Kamlet and Taft. The lipophilic activity of the investigated hydantoins was estimated by the calculation of log ₁₀ P values with the Advanced Chemistry Development Software. The calculated values of log ₁₀ P were correlated with the ratio of the contributions of specific solvent interactions, and, by employing the linear dependence thus obtained, the pharmacological activity of the studied hydantoin derivatives is discussed.     

Prediction of soil organic carbon partition coefficients by soil column liquid chromatography

To avoid the limitation of the widely used prediction methods of soil organic carbon partition coefficients (KOC) from hydrophobic parameters, e.g., the n-octanol/water partition coefficients (KOW) and the reversed phase high performance liquid chromatographic (RP-HPLC) retention factors, the soil column liquid chromatographic (SCLC) method was developed for KOC prediction. The real soils were used as the packing materials of RP-HPLC columns, and the correlations between the retention factors of organic compounds on soil columns (ksoil) and KOC measured by batch equilibrium method were studied. Good correlations were achieved between ksoil and KOC for three types of soils with different properties. All the square of the correlation coefficients (R2) of the linear regression between log ksoil and log KOC were higher than 0.89 with standard deviations of less than 0.21. In addition, the prediction of KOC from KOW and the RP-HPLC retention factors on cyanopropyl (CN) stationary phase (kCN) was comparatively evaluated for the three types of soils. The results show that the prediction of KOC from kCN and KOW is only applicable to some specific types of soils. The results obtained in the present study proved that the SCLC method is appropriate for the KOC prediction for different types of soils, however the applicability of using hydrophobic parameters to predict KOC largely depends on the properties of soil concerned.     

钇离子及其阳离子卟啉配合物与金黄色葡萄球菌的相互作用

用LKB-2277生物活性检测系统考察了Y~(3+)，TMP及其阳离子型钇卟啉配合物 {[Y(TMP)(H_2O)_3]Cl, TMP = 5, 10, 15, 20-四（4-甲氧基苯基）卟啉}对金黄色 葡萄球菌全程代谢作用的影响，测定了Y~(3+)，TMP和[Y(TMP)(H_2O)_3]Cl对金黄 色葡萄球菌作用的产热曲线，根据产热曲线求算了金黄色葡萄球菌在Y~(3+)，TMP ，[Y(TMP)(H_2O)_3]Cl作用下生长代谢的速率常数k_1，k_2，抑制率I_1，I_2，和 半抑制浓度IC_(50)~1，IC_(50)~2等热动力学参数。实验结果表明：Y~(3+)，[Y (TMP)(H_2O)_3]Cl对金黄色葡萄球菌的生长代谢有双向调节作用，在低浓度下表现 为刺激作用，高浓度为抑制作用，而TMP对金黄色葡萄球菌的生长代谢主要为抑制 作用，在低浓度下表现为刺激作用，高浓度为抑制作用，而TMP对金黄色葡萄球菌 的生长代谢主要为抑制作用，对金黄色葡萄球菌的抑制作用[Y(TMP)(H_2O)_3]Cl > TMP > Y~(3+)。     

Solubility and Flory Huggins parameters of SBES, poly(styrene-b-butene/ethylene-b-styrene) triblock copolymer, determined by intrinsic viscosity

Solubility parameter and Flory Huggins interaction parameter of a triblock SBES have been obtained from intrinsic viscosity measurements. The solubility of the block copolymer in all solvents (methyl-cyclohexane, cyclohexane, cyclopentane, toluene and benzene) was found good except in the case of n-hexane. The results obtained are similar to other found in literature for SBR and SBS rubbers, and indicate that cyclohexane and cyclopentane and methylcyclohexane are the most compatible solvents for this kind of polymer.     

STABILITY OF POLY（N,N＇-METHYLENEBISACRYLAMIDE-co-4-VINYLPYRIDINE） MICROGEL DISPERSION AND ADJUSTMENT OF THE HYDROPHOBICITY IN THE MICROGELS

In the UV-Vis spectra of pure light-scattering systems, there is an exponential relationship between absorbance and wavelength （A = Kλ^-n）. Here, the exponent n is named as flocculation-coagulation parameter. In the present paper, the effects of different additives on the stability of poly（N,N＇-methylenebisacrylamide-co-4-vinylpyridine） （poly（Bis-co-4-VP）） microgel dispersion were studied in detail via this parameter. The results showed that the stability of the dispersion mainly comes from the ionization of pyridine groups, making the microgel positively charged on its surface. This was confirmed by the measurement of Zeta potential and the result of conductometric titration. The result of fluorescence analysis indicated that the hydrophobicity in the microgels is enhanced with the increase in total 4-VP unit content.