Convergence of iterated boolean sums of simultaneous approximants

Explicit error estimates are given for the iterated Boolean sum of a sequence of simultaneous approximants; the rate of convergence is shown to be improved for smooth functions. The general results are applied in the case of the Bernstein, Durrmeyer and Stancu operators.     

在役加氢反应器试验板脆化和氢损伤的测定与研究

充分利用了带主焊缝的役后试板，在国内首次开展回火脆化、氢介质下断裂韧性与疲劳扩展的研究，结果表明，加氢反应器焊缝有明显的脆化表现。同时，核查了反应器开停车升温速度和降温速度规定，以及确定了裂纹允许尺寸的参考数据，为今后安全运行提供了充分的依据。     

一般应力比时焊接结构S－N曲线的预测方法

本文考虑了焊接结构的几何形状、受载形式、应力比、残余应力、尺寸效应以及材料等因素对疲劳寿命的影响，利用Ｐｅｔｅｒｓｏｎ公式和极值疲劳切口系数概念，建立了一般应力比时焊接结构Ｓ－Ｎ曲线的预估模型．文中对几类典型的焊接结构的Ｓ－Ｎ曲线进行了预测，预测值与实验结果符合较好．本文方法可以大量减少疲劳实验，具有一定的工程实用价值．     

DETERMINATION OF TOTAL NITROGEN IN BARLEY AND MALT BY COMBUSTION METHOD—COLLABORATIVE TRIAL

A combustion method, relying on the Dumas principle, for the determination of total nitrogen in barley and malt, has been collaboratively tested by the Analysis Committee of the European Brewery Convention. Repeatability, r₉₅, and reproducibility, R₉₅, values were 0.063 and 0.116% of dry matter, respectively, for samples with nitrogen contents in the range 1.23 to 1.86% N of dry matter. There was no significant difference between these values for barley and malt. The Analysis Committee approved the adoption of the combustion method for inclusion in Analytica EBC as an alternative method.     

A method of estimating the standard gibbs free energy of formation

Standard Gibbs free energy of formation (ΔG_f⁰), an important property needed in design calculations has been estimated using molar refraction, R_M. The linear relationships derived between ΔG_f⁰ and R_M tested with the data on 8 series of hydrocarbons at 228 compounds yielded average deviations comparable to the methods cited in recent literature. The method can be used as an alternative to the existing ones, because of its simplicity combined with reasonable accuracy.     

循环流液相等电聚焦方法及应用研究

利用循环流液相等电聚焦技术，对Ｈｂ、Ｃｙｔ．Ｃ和ＢＳＡ混合物进行分离，对ＲＮａｓｅＡ粗制品进行精制。该方法上样量大，活性回收好。对聚焦过程中扩散、对流和电渗的影响进行了讨论。     

开关磁阻电机传动技术及其应用

本文主要论述了开关磁阻电机传动技术的工作原理，系统结构和技术性能。介绍了该技术的发展背景、目前的应用情况和国内外发展水平。并对其前景表明了一些看法。     

The bioconversion of tunisian phosphorite usingAspergillus niger

It is well known that the production of phosphoric fertilizers by traditional methods is connected with certain environmental problems, particularly related to use of acids during the decomposition of natural phosphates. A basic problem is also the fact that only 15 – 20% of the phosphorus contained in superphosphates is assimilated by plants.The development of methods to process natural phosphates without acid precipitation has potential advantages and in this respect biotechnological processing of natural phosphates in order to obtain organo-mineral fertilizers is very promising. The possibility of bioconverting the phosphorus of natural phosphates by usingAspergillus niger fungi through their deep incubation has been investigated. The investigations aim to achieve a high degree of P₂O₅ extraction from the phosphates with conversion from a non-utilizable to a utilizable form. The influence of the fungal strain, the kind of nutritive medium and the time of incubation of the process of biological mobilization of the phosphate rock is examined.It was established that the time of incubation, the kind of micro-organisms of theAspergillus niger group, as well as the kind of nutritive medium, influence significantly the process of bioconversion and the conversion of phosphorus from non-utilizable to water-soluble and utilizable for plants form. A maximum degree 90% of phosphorus extraction in the form of water-soluble and citrate-soluble has been reached for 10-day incubation. Physicochemical examinations have been carried out and they have proved that, as a result of the produced organic acids, a process of decomposition of the initial Tunisian phosphorite takes place.     

45号钢二次枝晶臂间距与冷却速度的关系

本文利用可控平均冷却速度的单向凝固实验炉测定了４５号钢在不同平均冷却速度下的冷却曲线，由此得到其在凝固期间的平均冷却速度Ｒ，相应地测量了不同平均冷却速度下试样的二次枝晶臂间距Ｓ２，通过回归，得到了如下关系式：Ｓ２＝７２７Ｒ－０．４１，并将引式成功地应用于实际生产中。     

Fractional composition of partly hydrolysed polyvinyl acetate and its compatibility with hydroxypropyl methylcellulose in aqueous solutions

Fractionation of partly hydrolysed polyvinyl acetate (PVA) was performed by warming of its aqueous solutions. The following properties of the obtained fractions were determined: viscosity, molecular weight and molecular weight distribution, surface tension, and absorbance in the IR range. The blockiness of the polymer molecules, characterized by their behaviour towards iodine-containing systems such as I₂,-H₃BO₃ and I₂,-KI, was estimated. Fractionation of the aqueous solutions of PVA by warming is based mainly on the different internal molecular structure of the separated products, i.e. on the length of the vinyl acetate blocks in the PVA molecules and, to a lesser extent, on the degree of hydrolysis and the degree of polymerization. The more blocklike are the PVA molecules, the less compatible are the polymers in the PVA-hydroxypropyl methylcellulose (HPMC)-water system. At phase separation in this sytem the PVA molecules which are not compatible with HPMC are, in the first place, those of the highest blockiness.