基于USB 2.0的光散射系统上位机软件设计与实现

为了方便用户直观明了地观测光电转换状态,在Microsoft Visual C+ 6.0和MFC等开发环境下设计开发了一个光静态散射上位机软件。上位机软件运用USB 2.0标准的接口芯片与下位机进行通信,可实现设备的打开、关闭以及数据的接收、解析、存储、显示等,还可实时绘制状态参数曲线以监测光电转换状态。详细介绍了该上位机软件的工作原理、结构、功能和特点,实际应用表明该软件具有良好的稳定性、完善的功能性和友好的操作界面等优点,可以满足光静态散射系统的需求。     

三维抛物型方程的一个高精度恒稳定的PC格式

对三维抛物型方程,构造了一个高精度恒稳定的PC格式,格式的截断误差阶达到O（△t^2＋△x^4）,通过数值实例验证了所得格式较现有的同类格式的精度提高了二位以上有效数字;然后将Richardson外推法应用于本文格式,得到了具有O（△t^3＋△x^6）阶精度的近似解,并将所得格式推广到了四维情形．     

Comparison of the Effect of an Organoclay,Triphenylphosphate, and a Mixture of Both on the Degradation and Combustion Behaviour of PC/ABS Blends

Summary: Polycarbonate Acrylonitrile-Butadiene-Styrene blends (PC/ABS) with flame retardants Triphenyl Phosphate (TPP), nanoclay and their mixtures were prepared in a twin- screw extruder. The morphological properties were characterized by X-ray diffractometry (XRD) which showed the intercalated structure of nanoclay in the matrix. Thermal stability of the samples was studied using Thermogravimetric Analysis (TGA), and the degradation kinetic parameters were determined using various methods including Kissinger, Flynn-Wall-Ozawa and Coats-Redfern methods. It was found that the sample containing both TPP and nanoclay has the highest activation energy. The activation energy order of PC/ABS blends with different flame retardant packages, obtained by Kissinger method agrees well with that obtained by Coats-Redfern. Cone calorimetry and limited oxygen index (LOI)/underwriters laboratory 94 (UL94) methods were used to investigate the fire behaviour and flammability of materials. The reduced mass loss rate (MLR), peak heat release rate (PHRR) and enhanced LOI of the composite containing mixture system confirmed a synergistic effect of TPP and nanoclay.     

Solid-state NMR on thermal and fire residues of bisphenol A polycarbonate/silicone acrylate rubber/bisphenol A Bis(diphenyl-phosphate) (PC/SiR/BDP) and PC/SiR/BDP/zinc borate (PC/SiR/BDP/ZnB) — Part II: The influence of SiR

Solid residues of bisphenol A polycarbonate (containing 0.45 wt% poly(tetrafluoroethylene))/silicone acrylate rubber/bisphenol A bis(diphenyl-phosphate) (PC/SiR/BDP) and PC/SiR/BDP/zinc borate (PC/SiR/BDP/ZnB) after thermal treatment were investigated by solid-state and liquid-state NMR, focusing on the role and interaction of SiR with the other components of the polymer blend.In PC/SiR/BDP, part of the SiR reacts to an amorphous silicate network rather than being completely released in the gas phase. The silicate network consists of Q₄ and Q₃ groups formed via intermediate D and T groups. The D groups are formed by a reaction of SiR with bisphenol-A units as well as phenyl groups of PC and BDP. In addition a small amount of silicon diphosphate was observed after thermal treatment at temperatures higher than 810 K. The same decomposition products (without SiP₂O₇) occur in the solid residues of PC/SiR/BDP/ZnB samples. The formation of intermediate D and T groups occurs earlier, at slightly lower temperatures. Any formation of a borosilicate network was excluded.The results also apply for the fire residues of PC/SiR/BDP and PC/SiR/BDP/ZnB and are thus valuable for understanding the impact of SiR on pyrolysis and flame retardancy mechanisms in the condensed phase during the burning of PC/SiR/BDP blends. SiR was found to influence the pyrolysis and the char formed. Beyond the replacement of highly combustible mechanical modifiers, SiR harbours the potential to enhance flame retardancy.     

The Analysis of Theophylline — Containing Pharmaceuticals by Room Temperature Phosphorescence

Abstract

A simple and specific technique is used in analyzing pharmaceutical preparations (capsules, elixirs, syrups, and tablets) for theophylline and related compounds. The procedure consists of dissolving (diluting) appropriate amounts of the preparations and standards in (with) a 1 M KI-water solution, spotting 5 μL of each resultant solution onto filter paper discs, determining the phosphorescence intensities at room temperature and comparing sample signal levels to those of standards. The quantities of active ingredients and standards used in the determinations ranged from 25 ng to 1 μg. The results indicate that room temperature phosphorescence is useful for analyzing pharmaceutical preparations where active ingredients are usually contained in a wide variety of matrices.     

Enhancement of Sensitivity for Antimony Determination in Atomic Absorption Spectrophotometry by Introducing Stibine into an Argon-Hydrogen Flame

Abstract

The sensitivity of antimony determination with atomic absorption spectrophotometry is enhanced to a large extent by introducing stibine gas into an argon-hydrogen flame. As a reducing agent, zinc tablet made from the zinc powder paste with water is successfully used for quantitative and rapid productions of stibine from antimony (III) solution. The sensitivity for 1% absorption of the signal is estimated to be about 0.004 ppm of antimony.     

联立方程组新解法测定面康净片中两组分含量

采用联立方程组新解法不经提取分离直接测定面康净片中甲硝唑和维生素Ｂ６的含量。甲硝唑和维生素Ｂ６的平均回收率和相对标准偏差分别是１０１．４％，０．９７％和１００．６％，１．３１％。方法简便、快速、准确。     

CPA-矩阵法测定舒尔芬片剂中两组分的含量

本文采用ＣＰＡ－矩阵法不经分离同时测定舒尔芬片剂中双氯芬酸钠和磷酸可待因的含量。计算程序用ＢＡＳＩＣ语言编制。双氯芬酸钠和磷酸可待因的平均回收率及ＲＳＤ分别为９９．８５％，０．４６％和９９．８０％，０．５０％。方法简便、快速。     

A total synthesis of verbenachalcone, a bioactive diaryl ether from Verbena littoralis

Verbenachalcone 1, isolated from the aerial part of Verbena littoralis H. B. K. (Verbenaceae), has successfully been synthesized by employing anodic oxidation of the phenol derivative 3, as the key step. The bromine and chlorine substituents of 3 effected regioselective introduction of a methoxy group, as well as modulating the oxidation reaction. A flow-cell type apparatus of anodic oxidation provided the desired diaryl ether 4 in good yield.     

High performance liquid chromatographic analysis of dehydroepiandrosterone and its pharmaceutical tablet formulation

A rapid, sensitive and stability indicating high performance liquid chromatographic method was developed and validated for the analysis of dehydroepiandrosterone (DHEA) in pharmaceutical tablet formulation. The analysis was done on a Supelcosil C(18) column (25 cm x 4.6 mm i.d., 5 microm). The mobile phase consisted of methanol:sodium acetate buffer solution (5 g/L):acetic acid (500 mL/L), 57:42:1, v/v/v, adjusted to pH 5 at a flow rate of 1 mL/min. Detection was carried out at a wavelength of 258 nm. The polynomial regression data for the calibration curve showed good linear relationship in the concentration range of 0.2-1 mg/mL with r = 0.9996. The method was validated for precision, accuracy and recovery. The limit of detection was found to be 50 ng/ microL. The method was applied for the analysis of DHEA in its pharmaceutical tablet formulation. The effects of different buffers and alcohols on the retention of DHEA were studied and the role of acetic acid as an organic phase modifier was also investigated.