A new spectrophotometric method for the determination of ferrous iron in the presence of ferric iron

A new spectrophotometric method for the determination of ferrous iron concentration in samples containing ferric iron is presented. This new method is a modification of the Muir o-phenanthroline ferrous iron determination method. The new method consists of the quantitative spectrophotometric determination of Fe(II) by o-phenanthroline, but in which the ferric iron is complexed with sodium fluoride to eliminate interferences. A critical experimental comparison between the Muir spectrophotometric method, the Kolthoff titrametric method and the new proposed method is presented. Whenever Fe(III) accounts for more than 50% of the total iron in a sample, the method of Muir overestimates Fe(II). The proposed method has a range of 1–10 μg ferrous iron. It is as insensitive to other metal ions as the original method of Muir and is insensitive to Fe(III) up to a point where Fe(III) might be as high as 95% total iron. The proposed method is suitable for Fe(II) determination in bacterial leaching systems, where Fe(II) might be as low as 1% of total iron.     

Combination of the direct-forcing fictitious domain method and the sharp interface method for the three-dimensional dielectrophoresis of particles

In this paper, we combine the direct-forcing fictitious domain (DF/FD) method and the sharp interface method (SI) to resolve the problem of particle dielectrophoresis in three dimensions. The flow field is solved with the DF/FD method. The electric field governed by a Laplace equation with a jump coefficient across the particle surface is solved with the sharp interface (SI) method, and the dielectrophoretic force on particles is then calculated with the Maxwell stress tensor (MST) method. The main feature of our method is that both hydrodynamic and dielectrophoretic forces on particles are calculated with the interface-resolved methods instead of the point-particle model. The accuracy of the SI/MST method for the dielectrophoretic force without the consideration of the flow is validated via two problems: the electrostatic force on the particle in a non-uniform electric field, and the electrostatic force between two particles. The capability of the proposed DF/FD-SI/MST method is demonstrated with two numerical examples: the aggregation of particles due to the conventional dielectrophoretic force, and the motion of particles due to both conventional and traveling wave dielectrophoretic forces.     

Existence of two kinds of representations of the helmholtz-kohlrausch effect. II. the models

A formulation for predicting the Helmholtz-Kohlrausch (H-K) effect is given to the new VCC (variable chromatic color) method, which can derive the luminance factors of various chromatic object colors that match in perceived lightness with a fixed achromatic color. By using the formulation, the H-K effect by the VCC method is predicted within the whole chromaticity gamut including spectral colors. the magnitude of the effect in logarithmic scale by the VCC method is estimated to be twice as large as that by the VAC (variable achromatic color) method previously used. It is also stated that the VCC method is practically more important than the VAC method. the effectiveness of the new formulation is confirmed by comparing its predictions with the observations in two kinds of experiments. © 1994 John Wiley & Sons. Inc.     

气相色谱内标法测定苯乙烯纯度

采用安捷伦气相色谱7890完成苯乙烯纯度测定的内标法建岗,并与面积归一化法比较。内标法是通过测量内标物与被测组分峰面积的相对值来进行计算,测定的结果较为准确。缺点是操作程序较为麻烦,每次分析时内标物和试样都要准确称量。     

含氟废水的处理研究

以山东东岳化工有限公司焚烧炉排放含氟废水处理装置为实例,介绍了日本KURITA公司独创的KHDS法处理含氟废水的工艺。经过两年的运行证明该方法处理效果稳定,处理后水质达到国家规定的排放标准,即F-≤10mg/L。     

密炼机齿轮箱上水平基准块实际意义的分析

阐述了密炼机配套齿轮箱上所配置的水平安装基准块的意义和使用方法。目前很多密炼机齿轮箱在现场安装时,为保证水平基准块的水平度,多采用调整齿轮箱底部垫板和地脚螺栓的方法进行调整。该方法虽能使水平基准块水平度达到设计值,但是会影响内部齿轮的啮合情况,存在很大的风险。本文结合实例对该方法进行了分析,并给出了更合适的调整方法。     

A new method for the reconstruction of the particle radius distribution function from the sedimentation curve

A new method for the reconstruction of the particle radius distribution function from the sedimentation curve is proposed. This method permits us to obtain a continuous smooth distribution function. Two approaches are compared. The first approach is based on the calculation of the second derivative from the sedimentation curve. The second one is based on the solution of the original integral equation which describes a sedimentation process. Both of these approaches can be reduced to the problem of the solution of the Fredholm integral equation of the first kind. From the theory of integral equations, it is known that this problem is ill-posed. The usual methods lead to unstable solutions and we are forced to use special regularizing algorithms. In this paper, the Tikhonov regularization method is used to stabilize the solution of the integral equation. It is shown that the accuracy of both methods is higher than the accuracy of the graphical method, but the approach based on the solution of the original integral equation gives a more stable solution than that based on the derivative. The accuracy of the new method permits us to reconstruct the fine structure of the particle radius distribution function. Such an analysis cannot be carried out with the rough bar diagram obtained from the graphical method. The new method is absolutely indispensable in technology for controlling the degree of powder fineness.     

Fenton法的反应机理及类Fenton法的应用研究

Fenton法是高级氧化技术的一种,包括常规Fenton法和各种类Fenton法,在高浓度、难降解和有毒害的工业废水的处理中取得了较好的效果。文章介绍了Fenton法的反应机理以及各种类Fenton法的应用和发展,并对备类型的优势、问题和发展趋势作出评述。     

平行板谐振法测量高介电材料微波特性

讨论高介电材料介电常数、损耗角正切的测量技术、测量基本原理及相关参数的计算方法。介绍平行板谐振法的测量方法、测量装置和测量系统,阐述该方法的软硬件构成。给出实际测量中模式的判别方法及测量误差分析,并给出部分测量结果。介电常数ε,的测量相对误差小于0．26％,损耗角正切tanδ的测量相对误差小于7．5％。通过不同的方法对所选取的新型高介电材料微波特性进行测量,对比测量结果,验证该测量方法的正确性。     

Existence of two kinds of representations of the helmholtz-kohlrausch effect. I. the experimental confirmation

In the representation of the Helmholtz-Kohlrausch effect, a new method (the VCC method using variable chromatic colors) is proposed in addition to the method used so far (the VAC method using variable achromatic colors). The new VCC method showed a significantly larger Helmholtz-Kohlrausch effect than the VAC method previously used. For practical applications, the results by the VCC method are more effective than the VAC method. Three kinds of experiments are reported for clarifying the difference in effect between the two methods. © 1994 John Wiley & Sons, Inc.     

精馏-结晶联合分离法分离挥发度相近物系

研究了精馏 -结晶联合法的分离工艺 ,介绍了精馏 -结晶联合分离法的传质机理、数学模型、操作线方程。用对二氯苯 -邻二氯苯物系 ,对精馏 -结晶联合分离法与纯精馏方法进行了对比 ,结果表明 ,前者设备投资比后者节省 6 0 % ,能耗节省 5 7% ,冷却水消耗减少 5 7% ,表明它是一种很有开发前景的工业分离方法。     

Analysis of the stress distribution in two-dimensional bins by the method of characteristics

The method of characteristics, as outlined by Sokolovski [8], is used to calculate the stress distribution in two-dimensional parallel-sided bins containing granular material under either a uniform or zero surcharge. Both active and passive states are considered and the analyses are extended to include cohesive as well as cohesionless materials.In the active state, a continuous stress distribution is generated. The method of computing this has been investigated by many workers [3, 8, 9]. In the passive state, however, a discontinuity is shown to emanate from the top comer and be “reflected” at the centreline and wall, thus proceeding down the bin. The numerical method of computation is outlined.Wall stresses by this method are compared with those by the Janssen—Walker method [5]. There are large discrepancies, especially in the passive state, although the somewhat oscillatory plot of stresses by the method of characteristics does seem to be about the corresponding Janssen—Walker curve.     

流化床干燥器中临界湿含量测定

介绍用气相法和固相法测定流化状态下物料临界湿含量的方法，并将实验结果与洞道式干燥器中测得的数据做了比较。结果表明，用气相法测定流化状态下物料临界湿含量具有操作简便、快速和省料的优点。     

Iterative evaluation of the complex constants of piezoceramic resonators in the thickness mode

An iterative method is presented for the characterization of lossy piezoelectric materials in the thickness resonant mode, which allows to calculate the frequencies at which the electrical impedance is to be measured. This new method considerably reduces the measurement time by separating the programs for data acquisition and for processing thus simplifying the measurement procedure. The accuracy of the method was tested for several piezoceramic materials, covering a wide range of values of the thickness coupling factor and mechanical quality factor. The new method proved to be as accurate as other iterative methods, but it is easier to apply.     

An analytical method for the determination of cationic flocculants of the epichlorohydrin-dimethylamine condensate type

A method for the analysis of epichlorohydrin-dimethylamine flocculants is presented. The method is applicable to concentrations of flocculant of between 2 and 60 parts per million. These concentrations are used in coal and other mineral processing operations. An extension of the method may be used to give semiquantitative estimations of higher concentrations.     

不同处理方法对鱼金注射液含量影响

建立鱼金注射液含量的气相色谱测定方法,研究鱼金注射液萃取、回流两种处理方式注射液含量变化情况。采用键合交联聚乙二醇为固定液的毛细管柱分离,氢火焰离子化检测器检测,对两种方法提取出的甲基正壬酮进行定量分析。结果表明,鱼金注射液在萃取条件下含量更高、更稳定,确定为鱼金注射液质量标准样品处理方法。     

Testing the accuracy of methods for the computation of CIE tristimulus values using weighting tables

The least squares method for computing colorimetric weighting tables is presented and its connection with the optimum weights method is investigated. Each requires solving three linear systems of equations with the same coefficient matrix but three different right hand side vectors. It is shown that the two methods have nearly the same performance when the wavelength interval of the data is large. The two methods however, will perform differently when Δλ is small. Comparisons are also made between the least squares method, the optimum weights method, the zero‐ and second‐order weighting tables, and the ASTM weighting tables, both the original 1985 tables and the new 2013 Tables V and VI. The results show that the least squares method is the best for measurement intervals equal to or lower than 10 nm, and is competitive with the optimum weights method for 20 nm steps. The results presented in this article will contribute to the work of CIE Technical Committee TC1‐71 Tristimulus Integration as it seeks to make recommendations for the calculation of tristimulus values. © 2015 Wiley Periodicals, Inc. Col Res Appl, 41, 125–142, 2016     

原子吸收标准加入法测定染料中铜含量

采用原子吸收光谱标准加入法测定染料中微量铜含量,方法简便快速,特征浓度为0.299μg/mL·1%,检出极限为0.002μg/mL,百分回收率为99.2%.     

水中氰化物测定方法改进及回收率提高探讨

水中总氰化物的测定是水质全分析中的一项毒性含量指标。它是衡量水体中生物生存、人类饮用用水、工业生产用水的重要参数。但其含量监测方法(GB7486-1997)步骤繁琐、费时。作者提出了在原方法基础上用蒸馏水分别代替氢氧化钠作为氰化氢吸收液和氰化钾稀释液的实验方法，通过对照试验分别采用不同浓度样品进行回收率测定。测得该法标准偏差为0．0004、检出限达到0．0026，监测效果较好，在一定程度上简化了试验操作的繁琐性。并讨论了使用改进后方法对于提高该法回收率测定的几点建议。     

A modification of the p-anisidine method for the determination of free and total gossypol

Summary A modification of the Pons and Guthrie method for determining free gossypol in cottonseed materials is presented. The use of aniline, rather than p-anisidine, as the color-producing reagent is necessary if meals containing dianilinogossypol are to be analyzed correctly. Increasing the reaction temperature eliminates a serious weakness in the method and results in greater accuracy. The proposed method is applicable to all types of cottonseed meal now marketed. A slight modification of the Pons method for total gossypol is also presented. By doubling the strength of the oxalic acid used to hydrolyze bound gossypol and by using aniline to develop the color, the method is made applicable to chemically treated meals containing dianilinogossypol. Presented at 45th annual meeting, American Oil Chemists' Society, San Antonio, Tex., Apr. 12–14, 1954.