Effect of Oil/Water Ratios on the Phase Behavior and the Solubilization Ability of Microemulsion Systems Containing Sodium Dodecyl Sulfate

An α–ε–β fish-like phase diagram of three phase microemulsions was proposed and used to investigate the phase behavior of the microemulsion systems sodium dodecyl sulfate (SDS)/alcohol/oil/water at various oil/water ratios. Related physicochemical properties of the microemulsion systems were calculated. As the oil/water mass ratio increases, the solubility (ε _B) of the alcohol increases, while both the mass fraction of alcohol in the interfacial layer (A ^S) and the solubilization ability (SP ^∗) decrease. The effect of oils on the properties of the microemulsion systems was investigated.     

Microwave-assisted synthesis of some novel fluorinated pyrazolo[3,4-d]pyrimidine derivatives containing 1,3,4-thiadiazole as potential antitumor agents

A facile microwave-assisted procedure for synthesis of novel fluorinated pyrazolo[3, 4-d]pyrimidine derivatives containing 1, 3, 4-thiadiazole is described. This protocol presented such advantages as short reaction time, high yields, simple purification and environmentally benign procedures. Their antitumor activities were evaluated against HL-60 by an MTT assay. The preliminary results indicated that some title compounds exhibit more potent antitumor inhibitory activity than doxorubicin (DOX).     

The study on the dynamic response performance of PEMFC with electrodeposited RuO_2·xH_2O-Pt/C electrode

Dynamic response performance of proton exchange membrane (PEM) fuel cells affects its durability and reliability significantly. In this study, electrodeposited RuO2 xH2O-Pt/C was prepared to promote the PEM fuel cell dynamic response performance. The prepared RuO2 xH2O-Pt/C was characterized by scanning electron microscopy (SEM) equipped with energy disperse spectroscopy (EDS), which shows that RuO2 xH2O was electrodeposited on the surface of Pt/C. Performance of single cells with and without RuO2 xH2O-Pt/C at the cathode under a certain operating condition was studied using cyclic voltammetry, electrochemical impedance spectra (EIS) and polarization curve techniques. When the fuel cell modified with RuO2 xH2O-Pt/C was operated at lower pressure, a faster and more stable dynamic response could be found. Modifying with RuO2 xH2O-Pt/C composite material not only slightly increases the single cell performance but also dramatically improves the dynamic response performance, revealing that RuO2 xH2O-Pt/C can buffer the voltage undershoot whenever the current increases instantly.     

一种合成柔红霉素糖基类似物的新方法

与很多蒽环类抗生素一样,柔红霉素分子中含有3-氨基2,3,6-三脱氧己糖单元,糖基部分对药物分子的活性起着至关重要的作用.本文介绍了一种合成柔红霉素糖基类似物的新方法.     

A convenient and efficient H2SO4-promoted regioselective monobromination of phenol derivatives using N-bromosuccinimide

Abstract

A convenient, rapid H₂SO₄-promoted regioselective monobromination reaction with N-bromosuccinimide was developed. The desired para-monobrominated or ortho-monobrominated products of phenol derivatives were obtained in good to excellent yields with high selectivity. Regioselective chlorination and iodination were also achieved in the presence of H₂SO₄ using N-chlorosuccinimide and N-iodosuccinimide, respectively.     

On Stability and Strong Convergence for the Spatially Homogeneous Boltzmann Equation for Fermi-Dirac Particles

 The paper considers the stability and strong convergence to equilibrium of solutions to the spatially homogeneous Boltzmann equation for Fermi-Dirac particles. Under a cutoff condition on the collision kernel, we prove a strong stability in L ¹ topology at any finite time interval, and, for hard and Maxwellian potentials, we prove that the solutions converge strongly in L ¹ to equilibrium under a high temperature condition. The basic tools used are moment-production estimates and the strong compactness of the collision gain term. (Accepted 25, October 2002) Published online March 14, 2003 Communicated by P.-L. Lions