Thermometrische Schnellanalyse von Martin- und Hochofenschlacken sowie anderen Silicaten

Summary A novel method has been developed for the rapid analysis of silicates. Each component is determined from the temperature variation of the solution resulting from the addition to the test solution of a selectively reacting reagent. By suitable construction of the instrument the concentration of the component to be determined can be read directly in per cent. The determination of a component takes usually 4 to 8 minutes.In the test solution a temperature change proportional to the concentration of the component to be determined has been produced by the following reagents: sulphuric acid for barium, ammonium peroxodisulphate for iron, hydrogen peroxide for titanium, hydrofluoric acid for silicic acid, potassium permanganate for sulphur, ammonium molybdate and hydrogen peroxide for phosphate, potassium permanganate for manganese, potassium oxalate for calcium, diammonium hydrogenphosphate for magnesium, ascorbic acid for chromium. The above components can be determined without any separations. Only in the case of aluminium a separation of silicic acid from aluminium by dehydrating with perchloric acid in necessary. Thereafter the aluminium can be determined with hydrofluoric acid.The precision of the determinations is practically identical with the precision of the usual plant methods.     

On conditions affecting correctness of the measurement of solution/membrane equilibrium

The paper deals with simulation of conditions affecting the correctness of the measurement of a solution/membrane equilibrium which is determined by the method based on saturation of the membrane with the solution and subsequent extraction of a component into water or a suitable solution. Attention has been paid to the step when the solution remaining at the membrane surface is removed by washing with water. In this step, an amount of the component can be transferred into rinsing water which represents a loss of the component in the membrane, and the equilibrium is measured incorrectly. In the numerical simulation, the membrane has been considered as a slab, and unsteady-state mass transfer from the membrane into water has been solved. The simulation, whose results are given graphically, has shown that the loss of the component into water increases with increasing washing time, diffusivity of the component in the membrane, and liquid mass transfer coefficient. On the contrary, the loss of the component decreases with increasing partition coefficient and the membrane thickness. Furthermore, it has been found that the relative loss of the component is independent of the initial concentration of the component in the membrane.     

比值导数波谱法用于极谱及伏安法多组分分析

叙述了比值导数波谱法在电化学波谱解析中应用的原理。首先以混合物的极谱波（或伏安波）除以干扰组分的标准波谱得到比值波谱，再以比值波谱对电位求导得到比值导数波谱，藉此可消除干扰组分的影响。采用该法可对二组分体系进行分析，如选择合适的零交点便可对三组分体系进行分析。利用本法对苋菜红－日落黄的伏安波及铜－镉－镍的极谱波进行了解析及定量分析，获较好的结果。     

Synthesis of a macromonomer based on ɛ-caprolactone and 2-hydroxyethyl methacrylate

The mechanism of forming the macromonomer based on ?-caprolactone and 2-hydroxyethyl methacrylate under the effect of dibutyltin dilaurate has been investigated. The molecular-mass characteristics and the functional-type distribution of the macromonomer have been determined. It has been established that, as the concentration of the methacrylic component is increased, the contribution of side reactions related to its anionic polymerization rises. It has been shown that macromonomers with caprolactone backbones and terminal methacrylic and hydroxyl groups may be obtained. A method has been proposed for the purification of polymerization products from low-molecular-mass impurities, such as dimethacrylates and diols.     

Studies on the Surface Free Energy of Carbon-Carbon Composites: Effect of Filler Addition on the ILSS of Composites

The effect of an inorganic oxidation inhibitor, such as MoSi(2), on the surface energetics of carbon-carbon composites has been studied. According to contact angle measurements based on a linear fit method obtained from multiple testing liquids, such as water, diiodomethane, ethylene glycol, and glycerol, it is observed that increasing the MoSi(2) filler content of the composites leads to an increase of the surface free energy, mainly due to the increase of the London dispersive component of surface free energy, even if its specific or polar component is decreased. As an experimental result, the London dispersive component is strongly dependent on the results of the interlaminar shear strength of the composites. In this work, it has been possible to show that the results obtained from the linear fit method correlate with those determined from a two-liquid geometric mean when water and diiodomethane testing liquids are considered as a two-liquid pair. Copyright 2000 Academic Press.     

Application of the least-squares method in the matrix form: simultaneous spectrophotometric determination of rifampicin and isoniazid in binary pharmaceutical formulations

A least-squares method in the matrix form is described for the simultaneous determination of rifampicin and isoniazid in a mixture. The method allows the rapid analysis of binary pharmaceutical formulations with minimum error. The concentration of each component in the mixture has been determined spectrophotometrically by measuring the absorbance of the mixture at 5-nm intervals from 230 to 290 nm. To calculate the matrix of the proportionality constant a standard mixture was used for each component. All data analyses were performed on a personal computer.     

紫外光度法间接测定脱脂乳中的芽孢数量

为了有效控制乳制品生产过程、保证质量,克服芽孢杆菌传统计数方法周期长的缺点,本实验通过分光光度法检测芽孢中特异性物质2,6-吡啶二羧酸(DPA)。根据DPA浓度与芽孢数量的关系,建立了快速检测脱脂乳中芽孢数量的方法。本研究对脱脂乳及其芽孢处理、DPA释放及采用紫外分光光度法检测做了研究。通过准确度和加标回收率检验,建立DPA含量与芽孢数的线性关系,回归方程为y=0.2084x-0.9363,r=0.6998,经验证可有效估测脱脂乳中芽孢数量(P<0.05)。     

Homogeneity of solids: A proposal for quantitative definition

A simple formula has been deduced to predict the detectability of chemical homogeneity of solid substances by use of an analytical method with known spatial resolution. The formula includes the ratio of the spatial resolution of the method to the spatial distribution of the component to be determined, and the standard deviation of the method.     

Comparison of methods to enhance flame ionization detector (FID) signals in gas chromatography

The performances of some numerical methods to improve the signal to noise ratio are compared and applied to enhance noisy signals obtained in gas chromatography with capillary columns and a flame Ionization detector. Several methods have been considered: cutoffs In the Fourier transform of the recorded signal; real time numerical filtering; theoretical model curve fitting; and the correlation of a chromatogram recorded from a pseudorandomly injected sample with the pseudorandom injection function. Numerical real time filtering is shown to be the most convenient method when the main periodic component of the noise has been determined by Fourier analysis.     

Multi-Target Classification Pattern Recognition Applied to Computer-Aided Materials Design

Abstract

A multi-target classification pattern recognition method based on the principal component analysis (PCA) has been proposed for computer-aided materials design considering the multiple specialties of materials. The designed sample with probable optimal specialties is determined in such way that its representing point should be at the optimal region in the PC sub-space, where most optimal samples can be discriminated from non-optimal samples by means of features. The experimental parameters of the sample represented by this point can be obtained using a non-linear inverse mapping method from the PC sub-space to the original space. Based on the information provided using the method, several samples of V-PTC materials with optimal multiple specialties are synthesized.