分光光度计与计算机联机

人工记录的方法进无法准确记录分光光度计所批示的消光值，特别是因浓度（１０＾－５－１０＾－４ｍｏｌ／Ｌ）改变，而导致精度和准确度不高，采用计算机的方式是可以克服此种弊端，精确度和准确度都很高并有良好线性关系，且自动绘图（即经耳定律的线性图）并输出。此装置具有快速、直观、图文并茂等特点。     

分析化学中液膜富集方法的研究——痕量锰的液膜分离富集与火焰原子吸收光谱法测定

本文以N_(205)-P_(507)-煤油-液体石蜡-HCl液膜体系分离富集了痕量Mn~(2+),五次提取分离,富集倍数可达87倍,回收率近于98％。与火焰原子吸收光谱法结合,可富集测定ppb级的Mn~(2+)。     

Dense Sphene-type Solid Electrolyte Through Rapid Sintering for Solid-state Lithium Metal Battery

The sphene-type solid electrolyte with high ionic conductivity has been designed for solid-state lithium metal battery. However, the practical applications of solid electrolytes are still suffered by the low relative density and long sintering time of tens of hours with large energy consumption. Here, we introduced the spark plasma sintering technology for fabricating the sphene-type Li_1.125Ta_0.875Zr_0.125SiO₅ solid electrolyte. The dense electrolyte pellet with high relative density of ca. 97.4% and ionic conductivity of ca. 1.44×10^-5 S/cm at 30℃ can be obtained by spark plasma sintering process within the extremely short time of only ca. 0.1 h. Also the solid electrolyte provides stable electrochemical window of ca. 6.0 V(vs. Li⁺/Li) and high electrochemical interface stability toward Li metal anode. With the enhanced interfacial contacts between electrodes and electrolyte pellet by the in-situ formed polymer electrolyte, the solid-state lithium metal battery with LiFePO₄ cathode can deliver the initial discharge capacity of ca. 154 mA·h/g at 0.1 C and the reversible capacity of ca. 132 mA·h/g after 70 cycles with high Coulombic efficiency of 99.5% at 55℃. Therefore, this study demonstrates a rapid and energy efficient sintering strategy for fabricating the solid electrolyte with dense structure and high ionic conductivity that can be practically applied in solid-state lithium metal batteries with high energy densities and safeties.     

Special Mixing Behavior of Chelate-based Ionic Liquid with Methanol

Compared to the general ionic liquids (ILs), a significant deviation of the binary mixtures of 1-decyl-3-methylimidazolium tri(hexafluoroacetylaceto)-copper(II) ([C₁₀mim][Cu(hfacac)₃]) with methanol was found, indicating the way methanol interacts with ILs might be governed by the special structure of the chelating anion. IR results showed that the (C2-H) of 1-decyl-3-methylimidazolium hexafluoroacetylacetonate ([C₁₀mim][hfacac]) blue-shifted more significantly than that of [C₁₀mim][Cu(hfacac)₃], meanwhile the (C=O) red-shifted in [C₁₀mim][Cu(hfacac)₃], which is contrast with that in [C₁₀mim][hfacac]. Two-dimensional correlation analysis of the FTIR spectra indicated that the chelating cavity has little effect on the sequence of the ILs sites that interact with methanol. Combined with small angle X-ray scattering (SAXS) results, the picture of mixing processes in these two systems were proposed. Methanol interacts directly with the anion followed by the cation in [C₁₀mim][hfacac], while methanol preferentially enters the chelating cavity and enhances the packing effect in the [C₁₀mim][Cu(hfacac)₃] system.     

A bird nest-like manganese dioxide and its application as electrode in supercapacitors

A novel bird nest-like nanostructured MnO2(BNNS-MnO2) was prepared by a facile and cost-effective strategy. Their structures and morphologies were characterized by field emission scanning electron microscopy, transmission electron microscopy and powder X-ray diffraction. Capacitive behaviors were investigated by cyclic voltammetry and galvanostatic charge-discharge. The obtained nano-MnO2 possesses a well designed loose-assembled hierarchical nanoarchitecture with an appropriate crystallinity which gives rise to excellent performances as an electrode material for supercapacitors. A maximum specific capacitance of 917 F/g has been obtained at a current density of 5 mA/cm2 in 6 mol/L KOH aqueous solution, and a specific capacitance of 210 F/g has been maintained for 500 cycles. As the low cost of MnSO4 and KCr2O7 and the low reaction temperature, the present method avoids the requirements for complicated operations, time/energy-consuming and expensive reagents, and perhaps is ready for the industrialization of nano-MnO2 production.     

Comparative pharmacokinetic study of four major bioactive components after oral administration of Zhi‐Zi‐Hou‐Po decoction in normal and corticosterone‐induced depressive rats

A highly selective and efficient LC–MS/MS method was developed to determine the plasma concentration of magnolol, hesperidin, neohesperidin and geniposide following oral administration of Zhi‐Zi‐Hou‐Po decoction in normal and depressed rats. Plasma samples were pretreated by protein precipitation with methanol. Chromatographic separation was performed on an XTerra^® MS C₁₈ column using a gradient elution with a mobile phase composed of acetonitrile–0.1% aqueous formic acid. The proposed method was validated to be specific, accurate and precise for the analytes determination in plasma samples. The calibration curves displayed good linearity over definite concentration ranges for the analytes. The intra‐ and inter‐day precision of the proposed method at three different levels were all within <11.13% and the relative errors ranged from ?8.46 to 8.93%. The recovery of the four compounds ranged from 82.72 to 89.08% and no apparent matrix effect was observed during sample analysis. After full validation, the established method was successfully applied for comparing the pharmacokinetics of four components between normal and depressed rats. The results showed that the AUC and C_max of four analytes in depressed rats were significantly different from those in normal rats and might provide helpful information to guide the clinical use of Zhi‐Zi‐Hou‐Po to treat depression.     

A comparative study of GLS finite elements with velocity and pressure equally interpolated for solving incompressible viscous flows

A comparative study of the bi‐linear and bi‐quadratic quadrilateral elements and the quadratic triangular element for solving incompressible viscous flows is presented. These elements make use of the stabilized finite element formulation of the Galerkin/least‐squares method to simulate the flows, with the pressure and velocity fields interpolated with equal orders. The tangent matrices are explicitly derived and the Newton–Raphson algorithm is employed to solve the resulting nonlinear equations. The numerical solutions of the classical lid‐driven cavity flow problem are obtained for Reynolds numbers between 1000 and 20 000 and the accuracy and converging rate of the different elements are compared. The influence on the numerical solution of the least square of incompressible condition is also studied. The numerical example shows that the quadratic triangular element exhibits a better compromise between accuracy and converging rate than the other two elements. Copyright © 2008 John Wiley & Sons, Ltd.