LC-MS characterization of efficacy substances in serum of experimental animals treated with Sophora flavescens extracts

Anti-DHBV (duck hepatitis B virus) activity was found in the aqueous extracts of Sophora flavescens Ait. in vivo. Liquid chromatography/electrospray ionization ion trap mass spectrometry was applied to characterize the components in duck serum after oral administration of S. flavescens extract. Oxymatrine (1), sophoranol (2), sophoridine (3) and matrine (4) were identified in the serum. Further research on the four compounds was evaluated for their antiviral activity against HBV (hepatitis B virus) in cell culture. The results suggested that oxymatrine, sophoranol and matrine were the efficacy substances for anti-HBV activity in aqueous extracts of S. flavescens Ait.     

Stereoselective construction of spiro(butyrolactonepyrrolidines) by highly efficient copper(I)/TF-BiphamPhos-catalyzed asymmetric 1,3-dipolar cycloaddition

Pyrrole into one: The catalytic asymmetric 1,3-dipolar cycloaddition of cyclic aldimino esters has been accomplished for the first time, enabling facile access to spiro(butyrolactonepyrrolidines) containing one spiro quaternary center and three tertiary stereogenic centers (see scheme). The catalytic system performs well with a broad range of substrates, furnishing synthetically useful adducts in high yields, with excellent diastereo- and enantioselectivities under mild conditions.     

最小二乘法计算苯、噻吩和正辛烷在NaY上程序升温脱附活化能

采用程序升温脱附(TPD)技术测定了苯、噻吩和正辛烷在NaY上以不同升温速率升温时的TPD谱图. 利用TPD谱图的峰形和其微分曲线判断了程序升温脱附过程中的脱附级数. 提出了一种利用最小二乘法计算吸附剂/催化剂的脱附活化能及其动力学参数的方法. 以这些TPD谱图为基础, 分别采用传统TPD计算模型、最小二乘法以及一阶微分曲线法计算了苯、噻吩和正辛烷在NaY上的脱附活化能和动力学参数. 结果表明, 最小二乘法对在不同线性升温速率时的程序升温脱附活化能的计算结果是一致的.     

H∞ control for uncertain Takagi–Sugeno fuzzy systems with time-varying delays and nonlinear perturbations

This paper investigates the robust H_∞ control for Takagi–Sugeno (T–S) fuzzy systems with time-varying delays and nonlinear perturbations. Delay-dependent criteria for uncertain fuzzy systems have been proposed. The LMI optimization approach is applied to solve the H_∞ control problem and find the minimization of H_∞ norm bound. Computer simulations show that significant improvement over the previous results can be obtained.     

Preparation of p-type ZnO:(Al, N) by a combination of sol--gel and ion-implantation techniques

We report the preparation of p-type ZnO thin films on (0001) sapphire substrates by a combination of sol--gel and ion-implantation techniques. The results of the Hall-effect measurements carried out at room temperature indicate that the N-implanted ZnO:Al films annealed at 600\du\ have converted to p-type conduction with a hole concentration of $1.6\times10¹⁸cm^-3, a hole mobility of 3.67cm²/V.s and a minimum resistivity of 4.80cm.\Omega$. Ion-beam induced damage recovery has been investigated by x-ray diffraction (XRD), photoluminescence (PL) and optical transmittance measurements. Results show that diffraction peaks and PL intensities are decreased by N ion implantation, but they nearly recover after annealing at 600\du. Our results demonstrate a promising approach to fabricate p-type ZnO at a low cost.     

Benzene Adsorption in Microporous Materials

The adsorption behaviour of benzene in silicalite-1, AlPO₄-5 and EU-1 has been investigated using gravimetric techniques and molecular simulation methods. For the one-dimensional, 12-membered ring (MR) channels of AlPO₄-5 and the unidirectional, 10-MR channels with 12-MR side pockets of EU-1, the isotherms of benzene show simple type I behaviour. For the three dimensional 10-MR channels of silicalite-1, an anomalous behaviour of the benzene molecules sorbed has been observed. Two steps at loadings of ca. 4 and 6 molecules per unit cell [m.(u.c.)⁻¹], respectively, and an hysteresis loop between loadings from 6 to 8 m.(u.c.)⁻¹ can be found in the isotherms of this system. These stepped isotherms can be classified as showing type VI isotherm behaviour but in this system the reasons behind the steps are of a new and novel nature. These abnormal adsorption properties have been ascribed to the subtle interplay of increased sorbate-sorbate interactions and decreases in the entropy of sorption due to the energetically heterogeneous surfaces which are present in silicalite-1. The composition and structure of the silicalite-1 samples also play an important role on the adsorption properties of this system.     

嵌入定理和BZ反应机理研究

The central object of this work is to explore a method, which can be used to get information of other dynamic variables from the dependent time behaviors of any one dynamic variable in complex systems. The embedding phase patterns of o-NH2C4COOHBZ reaction systems were made based on embedding theorem and the experimental data of concentration of bromine ion received by computer. A saturated embedding dimension m≥8 has been shown, and a related BZ reaction mechanics with 10 chemical species as dynamic variables was presented and resolved by Gear algorithm. The concentrations with time of Br-. Mn3+, HBrO2, HOBr and BrO2 were simulated.     

环戊烷和环己烷在silicalite-1上的吸附、扩散和热脱附

Adsorption,diffusion and thermal desorption features of cyclopentane and cyclohexane in silicalite-1 have beeninvestigated using the intelligent gravimetric technique.Both the saturation adsorption loadings and diffusion coef-ficient of cyclopentane were greater than those of cyclohexane.The diffusivity of cyclopentane was about one orderof magnitude greater than that of cyclohexane at the same temperature and initial loading.For cyclopentane,therewas only one kind of desorption process at adsorption loadings lower than 4 muc(molecule per unit cell),but twodesorption processes appeared at the adsorption loadings higher than 4 muc.While for cyclohexane,one desorptionprocess was found in the whole range of loadings.Both thermal desorption peaks of cyclopentane and cyclohexanemoved to higher temperature region with increasing loading.     

氧非正分La0.9Ba0.1MnO3-δ/SrTiO3:Nb p-n异质结的整流特性研究

利用脉冲激光沉积技术在掺Nb的SrTiO₃衬底上制备了氧非正分La_0.9Ba_0.1MnO_3-δ/SrTiO₃:Nb p-n异质结.在20—300K这一较宽的温度范围内获得了光滑的整流曲线.整流实验表明：该p-n异质结的正向扩散电压V_D随着温度升高在薄膜金属—绝缘转变温度附近出现极大值,表现出与氧正分La_0.9Ba_{0. 关键词： 0.9}Ba_0.1MnO_3-δ薄膜')" href="#">La_0.9Ba_0.1MnO_3-δ薄膜 锰氧化物p-n结 整流性质