Physico-Chemical Aspects on Uranium and Molybdenum Extraction from Aqueous Solution by Synthesized Phosphinimine Derivative Chelating Agent

Journal of Inorganic and Organometallic Polymers and Materials - To retain uranium and molybdenum ions from G.Gattar leach liquor (GI), North Eastern Desert, Egypt, a new fabricated chelating...     

Correction to: Physico-Chemical Aspects on Uranium and Molybdenum Extraction from Aqueous Solution by Synthesized Phosphinimine Derivative Chelating Agent

Journal of Inorganic and Organometallic Polymers and Materials -     

Some Aspects of Polymer Stabilisation

Abstract

Basic principles of polymer oxidation and the mechanism of action of antioxidants are briefly discussed and applications of different antioxidant functions are outlined. Harnessing the processing operation has contributed to the development of targeted reactive processing methods designed to enhance antioxidant performance and polymer durability.     

提高物理化学教学效果的三个方面

物理化学作为化学化工类专业的主干课程,其教学效果的好坏直接关系着学生专业能力的发展。本文从主动质疑的思考习惯、前后联系的学习方法和应用知识的实践意识三个方面,介绍了我们在物理化学教学中的教学实践和体会。     

Some Aspects of the Theory of Adhesive Joints

The molecular and the rheological theories of adhesion are compared and the limits of their applicability discussed.     

Some Probabilistic Aspects in the Discovery of Species

Abstract

From a population containing m different kinds of species in various proportions, units are drawn randomly until all the species are discovered. We show that, irrespective of whether the population is finite or infinite and, in the first case, whether the successive draws are with or without replacement, the number of trials needed for the discovery of all the species is stochastically minimized and hence has the minimum expected value when the species are as equally abundant as possible.     

Some Fundamental Aspects of Transfer Printing

Conventional studies of integral sorption rates to determine diffusion coefficients cannot be applied to transfer printing. A simple technique based on the Daynes time–lag method is described which allows the steady–state diffusion coefficients of dyes to be determined under conditions of transfer printing. Both diffusion coefficients and activation energies of diffusion are similar to those found in vapour–phase and heat–fixation methods of dyeing. The saturation values and extent of fibre–bundle penetration by dye vapour are discussed in terms of dye flux to the surface and mean free–path lengths over a range of ambient pressures.     

On the pH-Dependence of Greducing in the Radiation Chemistry of Aqueous Solutions

Alkaline N₂O-saturated solutions of 2-D-2-propanol and ferri-ferrocyanide mixtures were irradiated. The results indicate that G_red, which is the sum of G_eaq + G_H = 3.3, is pH-independent in the range 11 – 14. The results do not indicate that G_eaq and G_H are pH-dependent.     

Mass Transfer in Molybdenum Extraction from Aqueous Solutions Using Nanoporous Membranes

Modeling of non‐disperse solvent extraction of molybdenum(VI) with PC‐88A as extractant and a nanoporous hollow‐fiber membrane contactor as extractor was performed. Computational fluid dynamics was applied for modeling and simulation of molybdenum extraction. Concentration, pressure, and velocity distributions for molybdenum were determined. The extraction of Mo⁶⁺ was greatly influenced by the flow rate of feed solution. The extraction efficiency was reduced with higher feed flow rate and increased with the molybdenum content in the feed. The pressure drop along the shell side of the membrane extractor was found to be not significant, being one of the advantages of membrane extractors which assist in reducing the operational costs. The proposed simulation method is capable to prognosticate the performance of solvent extraction of molybdenum in membrane extractors.     

电镀车间设计简介

<正> 电镀是一项应用十分广泛的表面处理技术,其内容复杂、品种繁多。通过电镀我们获得的产品部件光亮美观、防锈耐用、防腐耐磨,从而延长了使用寿命,增加了表面强度。电镀的原理是:电镀液通过电解作用,将溶液中金属离子在镀件上凝聚而实现,对于不同形状,不同用途的部件,我们选用不同金属镀层。为此,工艺上的处理方法、电镀液的配方、操作条件、控制参数等也各不相同。不但要使电镀产品达到质量好、消耗少、成本低,同时又要确保生产安全、环境卫生,除了与工厂生产技术与管理水平有关外,在很大程度上是取决于正确的设计。当前国内很多旧厂、老厂,由于设计考虑不周,因而给生产带来了许多不合理的后遗症,因此要求我们认     

Structure and Chemistry of Oxide Films Thermally Grown on Molybdenum Silicides

The oxides grown during thermal oxidation of molybdenum silicides were studied using electron microscopy, infrared absorption, and thermogravimetric techniques. Analysis of the oxidation mechanism based on thermochemical and diffusion rate data was correlated with experimental results. Because of the higher oxidation potential of silicon, it may be preferentially depleted from the silicide substrate to form a single-phase silica layer. Whether this occurs depends also on the relative diffusion rates in the oxide and substrate layers. Alternately, a duplex oxide layer containing both silica and molybdenum oxide phases will form. The molybdenum oxide phase is a necessary condition for the silicide pest, a low-temperature failure mechanism in which oxidation results in a nonadherent powder rather than in a protective film.     

Some Drying Aspects of Multistage Fluidized Beds

Multistage fluidized beds with and without downcomers to the horizontal perforated plates are used to dry food materials under different experimental conditions. The influence of various operating parameters such as inlet temperature of the heating medium, flow rate of the heating medium, material flow rate, and number of stages have been investigated. The performance of multistage fluidized beds with and without downcomers is compared and the difference in performance is explained based on stagnancy and short-circuiting of materials in each stage.     

Some Aspects of Thermal and Photochemical Autoxidation

Following an outline of the pioneering work of Haber's School, emphasis is placed on a critical review of the most important recent achievements. These embrace, in the area of thermal autoxidation: the concept of critical antioxidant concentration, the multiple effects of heavy metals (including catalyst-inhibitor conversion), the development of new synergistic antioxidant combinations composed of free radical acceptor and peroxide decomposer and, finally, Denisov's direct experimental evidence for the reaction of heavy metals with molecular oxygen in organic media in support of Uri's trace metal hypothesis of the general mechanism of the initiation of autoxidation. The following recent advances in the field of photochemical autoxidation are described: photosensitized initiation by trace metals and its inhibition, the singlet oxygen hypothesis, the inadequacy of phenolic antioxidants and the reliance on UV absorbers, the importance of energy transfer in photochemical protection leading to new stabilizers. A very recent innovation which is relevant to both thermal and photochemical autoxidation is highlighted, i.e., the development of new α-dithidiketone chelates, particularly bis (stilbenedithiolate) nickel (= NiS₄C₄Ph₄or, abbreviated, NiSDT) as antioxidants which combine in a unique way the properties of free radical acceptors, peroxide decomposers and UV stabilizers. They were then found to be the most powerful antioxidants for polyethylene and polypropylene.     

Some Aspects of Deriving Multicomponent Separation Potential

Theoretical Foundations of Chemical Engineering - The initial postulates and mistakes of the existing theory of potential of multicomponent isotope separation have been analyzed. It is shown that...     

药物化学教学的几点思考

为培养满足人类社会发展的新药研发人员,掌握药物化学知识非常重要。药物化学是药学类专业的一门核心课程,也是培养创新性新药研发人员的基础课程。关于如何改善药物化学的教学效果,笔者基于当前药物化学教学中存在的问题,从学科整合、教学方式、教师和优化实验等几个方面提出了自己的几点思考,以期提高教学质量。     

关于绿色化学教育的思考

本文依据绿色化学的定义和内涵、绿色化学的12条原则,思考了实施绿色化学教育的意义     

关于胶体化学的教学思考

胶体化学是一门古老而又年轻的学科,它的发展同步于工农业,在人们的生产和生活中有着广泛的应用.教学过程中首先讲述胶体化学的发展简史及胶体理论,接着对胶体的结构进行详细叙述,从而引发出对胶体性质的探讨和论述,最后由胶体的性质引起对胶体化学实际应用的讨论.这种层次分明的教学方式,可以进一步激发学生的学习积极性,有助于提高教学效果.     

Some Physico-Chemical Aspects of the Fibre-Matrix Interphase in Composite Materials

This paper deals with the influence of interphase formation on the stress transfer capacity of the fibre-matrix interface in single fibre composites and constitutes a brief review of our recent work. This influence is studied through the deviation of the experimental results from a recent theoretical analysis relating the interfacial shear strength to the reversible work of adhesion established between the fibre and the matrix. Two examples of interphases are considered: a transcrystalline layer in carbon fibre-PEEK composites and a pseudo-glassy interphase in carbon fibre-elastomer systems. In the former case, the low transverse mechanical properties of the transcrystalline layer lead to a decrease of the interfacial shear strength, whereas, in the latter case, the glassy behaviour of the interphase explains the improved interfacial stress transfer capacity.