用气室法研究分子反应动力学的新进展

介绍了研究分子反应动力学的两大主要实验方法之一的气室法、在研究有热原子参与的反应所取得的新进展，讲述了此方法“新用”的理论依据及相应的实验条件，至此，可以获得对分子反应动力学更精细的信息，例如，态－态分辨的微分反应截面，并对两大方法进行了“现代”对比。还对两方法的发展前景作了适度的分析。     

A Novel Method for Fabrication of a Glass-Electrode-Based Lipase Sensor

Lipase is one of the hydrolases. It catalyzes the hydrolysis of triglycerides, liberating fat acids. Based on its catalysis and the response of a glass electrode to the acids, a glass-electrode-based lipase sensor can be fabricated1, which has great potential in clinical medicine for the detection of blood fat in human serum samples.The immobilization of lipase on the bulb of a glass electrode is the key to the development of the sensor. In addition to its response time, which has a lot to do …     

Two New Steroidal Saponins from Diuranthera inarticulata

There are only three species in the genus Diuranthera (Liliaceae), which is endemic in the southwest of China1. Four steroidal saponins, diuranthosides A-C and chloromalo-side A were isolated from the fresh roots of D. major. This paper deals with the structure elucidation of two new steroidal saponins, diuranthosides D and E, which were isolated from the methanolic extract of whole plant of D. inarticulata Wang et K. Y. Lang.Diuranthoside D (1), [(]-38 (c 0.08, pyridine), afforded galac…     

Study on Phase Equilibrium Properties for CO_(2+) Cosolvent Binary Systems

Recently, the application of supercritical fluid technology is very interested, and it is applied in many areas for its special properties. The performance of supercritical fluid (SCF) as a solvent can be greatly affected by addition of an entrainer to the system. An entrainer can be added to a supercritical fluid to enhance its solvent strength and/or selectivity. Critical point data for these dilute supercritical fluid-cosolvent systems are imperative for the design of efficient separation …     

Study on the Structure of Supramolecular Inclusion Complex of β-Cyclodextrin with Retinoic Acid

The importance of Vitamin A for human health has been stressed in resent studies1, meanwhile its derivative so-called retinoic acid (RA) has been widely used as pharmaceutical to treat several types of skin disease and cancer2,3. However the application of retinoic acid is restrained for its poor water solubility, unstability and side effect on the human body.Cyclodextrins (CDs) are macrocyclic oligosaccharides built up from 6, 7, or 8 glucopyranose units called (, (, and (-CD, respectively…     

Three New Coumarins from Micromelum integerrimum

Micromelum integerrimum (Rutaceae) is a shrub growing in Yunnan Province. Leaves and barks of this plant have been used for the treatment of dysentery, and arthritis1. Previous researches revealed that this plant contained coumarins2-8. Micromelin, the main chemical constituent of this plant, showed significant inhibition against leukaemia P-388 cell line (T/C 149% at 10 mg/kg) but was inactive in lower doses, and also showed significant activity (T/C 228% at 1.25 mg/kg) against Lewis lung…     

ESTIMATION OF ACTIVATED ENERGY OF DESORPTION OF n-HEXANE ON ACTIVATED CARBONS BY TPD TECHNIQUE

1. INTRODUCTION In some cities of China, cancer and breath system diseases caused by the pollution of volatile organic compounds (VOCs) have been obviously increasing. The VOCs includes BTEX (benzene, toluene, ethylbenzene, and xylene), aldehydes, cresol, phenol, acetic acid, polynuclear aromatic hydrocarbons (PAHs), which have long-term human health implications. Emission of the VOCs has threatened the health of people seriously [1,2]. The pollution of the VOCs mostly hails from…     

Study on the energy transfer between UO_2~(2 ) and Eu~(3 ) in sol-gel derived titania matrix by luminescence spectroscopy

The TiO2 gel doped with UO22 and Eu3 has been prepared by a sol-gel method. The quenching of the UO22 emission by Eu3 and the energy transfer from the excited state of UO22 to the ground state of Eu3 have been investigated. The energy transfer has been studied by the measurement of luminescence lifetime τ, calculations of energy transfer efficiency ηET and energy transfer rate WET. The experimental results indicated that the quenching is combined static and dynamic mechanism, but the static mechanism is dominant.     

Rare Earth Complex Initiated Ring-Opening Polymerization of 2,2-Dimethyltrimethylene Carbonate

Aliphatic polycarbonate is a series of useful biodegradable materials attracting more interests recently. Poly(2,2-dimethyltrimethylene carbonate) (polyDTC) has been studied for a long time. Polymerization of DTC can be catalyzed by alkyl metals1, trifluoromethanesulfonic acid and its esters2, alcohol/methylaluminum diphenolate system3 and etc. Herein tris(2,6-di-tert-butyl-4-methylphenoxo) lanthanides (Ln(OAr)3, Ln=La, Nd) are firstly applied to initiate the polymerization of DTC. Ln(O…     

Synthesis and magnetic properties of CdS/α-Fe_2O_3 hierarchical nanostructures

CdS/α-Fe2O3 hierarchical nanostructures, where the CdS nanorods grow irregularly on the side surface of α-Fe2O3 nanorods, were synthesized via a three-step process. The diameters and lengths of CdS nanorods can be tuned by changing the ethylenediamine (EDA) and Cd ion concentrations. The magnetic investigations by superconducting quantum interference device indicate that the hierarchical nanostructures have an Morin transition at lower temperature (230 K) than that of the single bulk α-Fe2O3 materials (263 ...