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1.
A range of monoazo blue disperse dyes has been synthesised by coupling benzenoid and heterocyclic diazo components to aniline derivatives containing ester functions. The colour properties and wet fastness of the dyes on polyester at 1/1 standard depth have been examined and rationalised in terms of dye structure. Styryl dyes have also been prepared in order to compare their wet fastness properties to those of the azo dyes.  相似文献   

2.
The copolymer P(AM‐co‐4VP) of acrylamide (AM) and 4‐vinylpyridine (4VP) was synthesized by radical copolymerization in solution, and then the copolymer was quaternarized using dimethyl sulfate to produce cationic P(AM‐co‐4VP) (CPAV), a cationic polyacrylamide containing quaternary pyridine salt. Two series of CPAV have been synthesized. The structure and composition of the copolymer and the cationic copolymer were characterized by their FTIR, 1H NMR and ultraviolet spectra Flocculation and corrosion inhibition properties of the cationic copolymer were studied in detail and effects of cationic degree and molecular weight on the flocculation and corrosion inhibition properties were discussed. The results showed that cationic polyacrylamide containing quaternary pyridine salt possesses excellent flocculation, corrosion inhibition and other functions. The higher the degree of cationization, the better are these functions, and the molecular weight also effects the functions significantly. Copyright © 2003 Society of Chemical Industry  相似文献   

3.
An attempt is made to change the electrode properties of alkali silicate glasses containing various glass-formers and modifiers by introducing fluorine components into their compositions. Model systems with the initial hydrogen and metallic electrode functions are investigated. The study is based on the assumption that new ionogenic structural units with a mixed-anion constituent are formed in the glass structure. Lithium, sodium, and potassium silicate glasses with different fluorine contents are synthesized. Their potentiometric properties are studied. It is shown that the introduction of fluorine exerts the strongest effect on the electrode properties of alkali aluminosilicate glasses. An indirect corroboration is obtained for the assumption that strongly acid groupings containing fluorine can be formed in the glass network. It is found that the technological properties of the electrode glasses are significantly improved and the chemical durability in the potassium-containing system also becomes much higher. From the results obtained, the inference is drawn about the prospects of fluorine introduction into electrode glasses.  相似文献   

4.
Polystyrene particles were coated by electroless deposition of copper, nickel or copper and nickel. The metal-coated polystyrene particles were molded at high temperature and pressure into plaques, in which the metallic shell continuity was preserved and a continuous conducting metal network was formed. Very high conductivities at low metal concentrations (less than 1 percent v/v) are obtained by this procedure. The resistivity, dielectric constant, and dissipation factor of these metal containing composites are presented as functions of the metal concentration, frequency, and temperature. The metal containing composites exhibit reasonable flexural properties.  相似文献   

5.
Plastisol viscosity reduction and control is an important property specification in many vinyl plastisol formulations. A unique benzoate plasticizer is under development that functions as a viscosity reducer. It also is a highly solvating plasticizer in standard plastisol systems. Data are presented on the effects of the new benzoate plasticizer on the properties of phthalate‐ and benzoate‐containing plastisols and vinyl sheet.  相似文献   

6.
Unsteady axisymmetric boundary layer equations for power-law non-Newtonian fluids are analyzed. A number of new exact solutions containing arbitrary functions and free parameters are constructed using generalized or functional separation of variables. The solutions are obtained using a Crocco-type transformation reducing the order of the equations examined and simpler point transformations. Along with the exact solutions to axisymmetric boundary layer equations, some new exact solutions to planar boundary layer equations for non-Newtonian fluids are constructed. Several properties have been discovered that allow the exact solutions of the unsteady axisymmetric boundary layer equations to be generalized by including additional arbitrary functions therein. All results refer to an arbitrarily shaped streamlined solid of revolution.  相似文献   

7.
Modeling of the process dynamics needed for (linear-quadratic) design of multivariable composition control schemes in distillation is treated. It is illustrated how an (experimentally obtained) model consisting of simple transfer functions containing dead times is transformed into a sampled model, suitable for controller computation.

Two distillation systems, with quite different properties, are used in the simulations, illustrating the controller properties: a column modeled by Toijala and Fagervik (1972) and the experimental system modeled by Wood and Berry (1973).

The paper is focused on how errors in the process models affect the control properties of the multivariable control system. The relations between the model structure, the performance index, the control quality, and the sensitivity are discussed.  相似文献   

8.
功能水凝胶作为一种三维高分子网络结构的软湿材料,具有可灵活调控的功能特性,为设计和构建高性能柔性超级电容器提供了理想的材料。本文综述了近年来面向柔性超级电容器领域的功能水凝胶材料的研究进展,重点分类介绍了面向电化学双层电容器和赝电容器的功能水凝胶材料的设计构建和性能强化。探讨了通过水凝胶电解质及电极材料的组成结构设计和性能调控来提升超级电容器的电化学性能和力学性能的策略。同时,探讨了水凝胶电解质及电极材料的组成结构设计和性能调控在实现其自愈合、高耐寒等多样化功能特性方面的重要作用。最后,对功能水凝胶材料柔性超级电容器在高储能、高柔性、高保水、自愈合、高耐寒、绿色可降解等方面的未来发展进行了展望。  相似文献   

9.
Hydrophilic fluoropolymers were obtained by grafting phosphonated monomers onto activated poly(vinylidene fluoride) (PVDF). By using an ozonization technique, dialkylperoxide and hydroperoxide groups were formed onto PVDF which may be decomposed thermally in a subsequent step to initiate graft copolymerization. By using an iodometric titration technique, the effect of ozone oxidation time and temperature on the concentration of peroxides was studied. However, degradation was observed by viscosimetry and FTIR for the hardest ozonization conditions. An effect of the grafting conditions (monomer concentration and monomer end groups) on the degree of grafting was determined and diester‐acrylated phosphonate is grafted at a higher rate than are the homologous acid derivatives. Adhesion of the graft copolymers applied to galvanized steel substrates was studied. The experiments clearly show stronger adhesive properties of PVDF coatings containing phosphonic acid functions than those of the ones containing carboxylic acid functions. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 611–620, 1999  相似文献   

10.
一种功能性化妆品原料--透明质酸   总被引:10,自引:0,他引:10  
张延坤  金京顺 《日用化学工业》2004,34(2):111-114,118
论述了透明质酸的理化与生物特性、简易制备方法、特殊功能及其在化妆品中的应用,同时提供了几个常用的化妆品基础配方。透明质酸是一种对人体具有一系列特殊保护功能且性能优良的天然酸性黏多糖物质。它用于化妆品,可起到保湿护肤、抗衰老、营养皮肤、促进伤口愈合、抗菌消炎及稳定乳化等功能。展望了其在今后国内日化市场上的发展前景,为国内透明质酸资源的充分开发利用提供一些有益信息。  相似文献   

11.
李伟  欧阳藩 《化工学报》2000,51(Z1):348-351
液相色谱是现代生化分离的主要技术,填料是色谱技术的核心。本信息系统由填料数据库及填料综合评估系统组成,数据库中收录了近200种用于生化分离的离了交换、疏水及凝胶过滤色谱填料数据,包括基本特性参数、操作性能、稳定性、生产厂家及相关文献信息。综合评估系统针对离子交换填料,由筛选(鉴定性)评估及选优(水平性)评估两部分构成,可针对数据是否完备进行详细与粗略两种评估。系统目前数据量为26M字节,管理信息系统采用 Microsoft Access 2000。  相似文献   

12.
We have synthesized a series of epoxy resins containing melamine phosphate (MP) and investigated their thermal and flame retardation properties. MP functions as a hardener and a flame retardant or as an additive of the cured epoxy resin to enhance flame retardation properties of epoxy resins. The reactions of DGEBA cured in the presence of MP were monitored by NMR and FTIR. Our results show that in both reactive and additive modes, MP is effective in increasing limiting oxide index (LOI) and the char yields of epoxy resins at lower phosphorous content. We observed that flame retardation by MP in its reactive mode is better than in its additive mode; the same phenomenon was found also for the glass-transition temperature (T g). Thermogravimetric analysis (TGA) demonstrated that epoxy resins containing MP decompose at relatively lower temperatures than those lacking MP; this decomposition results in a protective layer forming that prevents the epoxy resins from decomposing further by combustion.  相似文献   

13.
噻吩并吡嗪是一类含有富电子的含氮杂环化合物,具有大的π-共轭刚性平面结构,这种独特的结构使其及衍生物表现出了许多优异的光电性能和生物活性。噻吩并吡嗪类化合物作为精细化学品的重要中间体,可在许多领域都有十分广泛的应用,本文介绍了噻吩并吡嗪的研究历史,综述了噻吩并吡嗪及其衍生物在光电材料方面的最新应用进展,并对噻吩并吡嗪及其衍生物的应用研究进行展望。  相似文献   

14.
The review summarizes the long-term experience in theoretical research of combustion of gasifying condensed systems with periodically varied pressure. Most results are obtained within the framework of the Zel'dovich-Novozhilov theory. The main properties of the linear function of the burning rate response to harmonically varied pressure are discussed. The concept of nonlinear response functions is introduced, which is illustrated by the explicit form of a number of second-order response functions. A new phenomenon is described: bifurcations of response functions with a varied amplitude or frequency of pressure oscillations. For the simplest gunpowder model containing three parameters only, the sequence of bifurcations of doubling of the burning rate oscillation period is studied, which finally leads to a random combustion regime. An analytical relation between the linear response functions to harmonically varied pressure and to an oscillating radiant heat flux is noted. An example of calculating the response function with allowance for thermal inertia of the gas phase is presented. __________ Translated from Fizika Goreniya i Vzryva, Vol. 41, No. 6, pp. 116–136, November–December, 2005.  相似文献   

15.
Thermolabile microcapsules are formed by interfacial polycondensation in which one of the wall-forming reactants contains azo functions. These reactants are compounds of the general structure X? R? N?N? R? X (X = ? OH, ? NH2, ? NCO, COCl). Their properties are described in detail. Experimental details of the microencapsulation such as particle size, dependence from stirrer speed and stability of the capsules are given. An ink ribbon containing a carrier covered with dye filled microcapsules is applied for thermal-transfer-printing.  相似文献   

16.
The use of artificial neural networks (ANNs) in the modeling and prediction of alkyd enamel coating properties, as well as in the sensitivity analysis that can be performed between the properties and the different paint components, are described. A feedforward neural network with sigmoidal activation functions was used with a conjugate gradient algorithm to recognize the complex input-output relation between the paint properties and the formula components. We restricted the study to only two properties of alkyd enamel paints: gloss and drying time. A database of five different families of alkyd enamel paints, containing the different components of the formulations as well as process information, was used in this study. The results obtained show, within the expected uncertainty tolerance, that predictive power of more than 90% for these two properties can be achieved. A sensitivity analysis was also performed using ANNs, yielding the relative importance of the different components of the formulation on the properties of the enamel coatings, which agrees with experience for gloss but gives mixed results for the drying time (apparently due to the high uncertainties in the measurement of this property).  相似文献   

17.
Gold nanoparticles exhibit novel optical and catalytic properties, are nontoxic and biocompatible, and attract considerable interest in a range of applications, e.g. photonics, diagnostics, and therapeutics. The morphology (size and shape) of the nanoparticles and their surface/colloidal properties are very important in the various applications. A methodology for the synthesis in aqueous media of gold nanoparticles with controlled size and shape and exceptional colloidal stability is reviewed. This methodology is based on designer polymers that can exhibit multiple functions on the basis of the polymer intramolecular and supramolecular organization. In addition to being water based, this methodology requires no external energy input and employs commercially available polymers, e.g., poly(ethylene oxide) containing Pluronics or Poloxamers, resulting in low cost and potential environmental benefits.  相似文献   

18.
Thermochemical changes occurring during wood welding were investigated in Eucalyptus saligna and Eucalyptus pilularis. Unwelded reference wood and material from welded interface were compared via Py-GC/MS, thermogravimetric analyses, X-ray photoelectron spectroscopy, and attenuated total reflection Fourier transform infrared spectroscopy to explain differences in mechanical properties of welded wood between species. It appeared that the species originally containing more condensed substructures also provided stronger joints. The condensation index after welding allowed validating that the adhesive properties of lignin are more accessible in such species. The presence of more carbonyl functions, attributed to carbohydrate solicitation during welding process, potentially made lignin less accessible. Changes following welding were evidenced by the contribution of extractive compounds, fatty acid chains, and terpenoids, possibly reacting with hydroxyl groups and leading to adhesive properties by chemical linkage through new covalent bonds formation. Results corroborate the better mechanical properties of E. saligna, providing stronger joints possibly due to more accessible adhesive properties by esterification between lignin and fatty acid.  相似文献   

19.
Coenzymes are often considered as remnants of primordial metabolism, but not as hereditary molecules. I suggest that coenzyme-like molecules (CLMs) performed hereditary functions before the emergence of nucleic acids. Autocatalytic CLMs modified (encoded) surface properties of hydrocarbon microspheres, to which they were anchored, and these changes enhanced autocatalysis and propagation of CLMs. Heredity started from a single kind of self-reproducing CLM, and then evolved into more complex coenzyme autocatalytic networks containing multiple kinds of CLMs. Polymerization of CLMs on the surface of microspheres and development of template-based synthesis is a potential evolutionary path towards the emergence of nucleic acids.  相似文献   

20.
Lactobacillus casei is a group of phenotypically and genetically heterogeneous lactic acid bacteria, able to colonize various natural and man-made environments. Strains of the Lactobacillus casei group have been widely studied with respect to their health-promoting properties. Several beneficial functions for the human organism have been attributed to regular consumption of food products containing these strains. Bacteria of the Lactobacillus casei group are of great interest for the food industry to improve food quality. A number of studies have been conducted in order to evaluate the viability of strains of Lactobacillus casei group as probiotic in dairy products, desserts, among others food products. Despite its importance for the food industry, the taxonomy of the Lactobacillus casei group is still unclear. This review discusses important studies related to characterization of strains of Lactobacillus casei group, the application of these bacteria as probiotic in different food products and the main beneficial effects attributed to regular consumption of products containing such microorganisms.  相似文献   

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