Photooxidation of ABS of long-wavelengths

The evolution of the photochemical degradation of ABS has been studied in conditions of long wavelength irradiation (λ's> 300 nm). The main photoproducts involved in the oxidative evolution have been identified by using FTIR spectroscopy and chemical titrations. A particular attention has been devoted to α–β unsaturated ketones that appear as secondary photoproducts. Those ketones present a low photochemical stability when exposed in the range 300–400 nm. Conditions for their formation have been experimentally studied. Formation of oxidation photoproducts has been also studied at the macroscopic level and it has been shown that their repartition in the polymer is heterogeneous. The origins of the heterogenities have been studied.     

A study of the effect of network angle of fabrics on kinetics of impregnation upon molding of articles made from carbon plastics

The permittivity coefficient, volume, and porosity of an elementary cell of fabric filler have been calculated. Two types of fabric structures have been considered using the example of carbon fabric: standard, in which filament yarn is cylindrical, and spread, it which it has a rectangular shape. A reflector of a mirror space antenna has been considered characterized by the presence of doubly curved surfaces is used as the object of study. Modeling of the kinetics of impregnation of reflector for two types of fabric structures has been carried out using the RAM–RTM program. In the work, the effect of the network angle on the duration of impregnation process has also been investigated. Based on the results of calculation, reflector samples have been made and their quality has been evaluated. Theoretical and experimental results have been compared.     

Thermodynamics of mixing of polymers

A method of calculating free energy of mixing of two polymers has been proposed. From a study of the sorption of organic solvents vapour by different polymers and their mixtures, Gibbs free energy of mixing for polymer-solvent systems are calculated. The free energy of mixing of two polymers has been calculated by the method proposed. Heats of mixing of polymers have been measured with a Calvet type microcalorimeter. Entropy of mixing has been calculated. Stabilities of polymer-polymer systems have been discussed.     

Synthesis and studies of structure and biological properties of D-homoanalogs of steroid estrogens

In order to estimate the potential of steroid estrogens modification, three D-homoanalogs of estrogens have been prepared; their structures and biological properties have been studied. The expansion of D-ring in such compounds has lead to strong decrease if the uterotropic action, however, the unfavorable hypertriglyceridemic effect has been retained. The latter has been eliminated by combined action of the studied steroids and ursolic acid; therewith the hypocholesterolemic activity has been retained.     

Kinetics of oxidation of some disaccharides in ammoniacal medium

Kinetics of oxidation of lactose, maltose, cellobiose and melibiose has been studied by hexacyanoferrate(III) in the presence of ammonia. A general mechanism involving the formation of intermediate enodiol anion has been suggested. The effects of dielectric constant and salts have been studied in detail. The oxidation products have been characterised by descending paper chromatography. Compensation effects have been observed.     

Study of acid-base properties of morin by tristimulus colorimetry

Acid-base properties of morin in aqueous solutions have been studied by means of chemical tristimulus colorimetry, and the ionization constants have been determined. The pK values have been assigned to the corresponding functional groups, and their dissociation scheme has been suggested. Diagram of distribution of ionic and molecular forms of morin at pH 1–13 has been constructed. Spectral parameters of equilibrium acid-base forms of morin have been determined.     

Kinetics of homopolycondensation of furfuryl alcohol

The kinetic features of the homopolycondensation of furfuryl alcohol in an aqueous medium in the presence of acids of different strengths have been studied. The second order of the reaction with respect to the monomer has been established. A kinetic scheme of the polycondensation reaction has been proposed, and the activation parameters of the process have been calculated.     

Fine structure analysis of the even parity configuration system of Ti I

Even-parity configuration system of Ti I has been considered on the basis of the experimental data available in literature. The fine structure analysis has been performed with the aid of a linked-parameter method of level-fitting calculations in a large multiconfiguration basis. Fine structure parameters have been determined and precise wavefunctions of even energy levels have been evaluated. Appropriate pseudorelativistic Hartree-Fock ab initio calculations of fine structure parameters have been presented for comparison purposes. Configuration interaction effects on even-parity configurations have been discussed.     

Electrochemical determination of synthetic antioxidants of bisdithiophosphonic acids

It has been found that bisdithiophosphonic acids with aryl substituents at the phosphorus atom quantitatively interact with electrogenerated halogens under the conditions of galvanostatic coulometry. Stoichiometric coefficients of the reaction between synthetic antioxidants and coulometric titrants-halogens have been determined. The corresponding reaction schemes have been proposed. The total antioxidant capacity (TAC) of the analytes has been estimated by their reaction with electrogenerated bromine. It has been demonstrated that bisdithiophosphonic acids bearing ionolic fragments demonstrate the highest TAC. It has been established that bisdithiophosphonic acids are irreversibly oxidized on a glassy carbon electrode at a potential of 800 mV with 0.1 M NaClO₄ in acetonitrile as the supporting electrolyte. The quantification limit and the analytical range of the analyte determination have been found.     

Continual stochastic description of systems with chemical reactions in the presence of a long-range interaction and concentration dependence of the electrical conductivity of electrolytes

It has been shown that recombination-dissociation processes influence the relaxation correction to the concentration dependence of the conductivity of electrolytes. A theoretical treatment has been carried out in the framework of the continual stochastic formalism of birth-and-death processes with a long-range interaction. Evaluations of the observed effects have been given and the possibility of their experimental measurement has been discussed. The question of the concentration dependence of the Hall effect has also been considered.     

Effect of the composition of polyacrylimide-forming copolymers on their processing

Thermomechanical studies of thermosetting copolymers of acrylonitrile with methacrylic acid and acrylamide with acrylic acid that form similar polyacrylimide foam plastics during curing have been performed. The dependence of the glass-transition temperatures of the copolymers on the degrees of intramolecular imidization has been calculated and confirmed experimentally. Procedures to control the curing rate have been proposed. The influence of plasticizing additives on the glass-transition temperatures, imidization, and foaming of foam-forming compositions has been studied. Plasticized powdered foam-forming compositions with delayed imidization have been developed, and temperature conditions for their processing have been determined.     

A study of the pectins of wild apples

Pectins have been isolated from five species of wild apples and have been characterized. They contain galacturonic acid, galactose, glucose, and arabinose residues. The titrimetric indices of the substances isolated have been determined. It has been shown by IR spectroscopy the pectins isolated are extracted partially in the form of pectic acids.     

The question of the production of Plantaglyutsid

The stage of extracting Plantaglyutsid from the leaves of rippleseed platain has been optimized by the methods of mathematical statistics. Information has been obtained on the optimum parameters of performing the process, as a result of which the yield of desired product has been increased and the amount of energy used and the consumption of extractant have been decreased.     

Kinetics and mechanism of the production of higher olefins from stearic acid in the presence of an alumina-supported nickel sulfide catalyst

A nickel sulfide catalyst which efficient in the decarbonylation of fatty acids to olefins and dienes has been obtained for the first time by treating alumina-supported nickel sulfate with hydrogen, and its properties have been studied. In its presence, the olefin selectivity of the reaction can exceed 90%. The kinetics of stearic acid deoxygenation to heptadecenes has been investigated, a kinetic model has been constructed, and a mechanism has been proposed for the reaction over this catalyst. Olefin oligomerization is the dominant side reaction. Kinetic evidence for the catalytic inhibition of oligomerization by nickel hydrides formed on the catalyst has been obtained. The compositions of active site–reactant adsorption complexes have been discussed.     

贵金属Au冷却过程中结构及能量变化的分子动力学计算机模拟

通过分子动力学方法,研究了不同冷速下贵金属Au在温度2000～300K的冷却过程中微观结构的变化特点。结果发现,冷却速度对Au的微观结构产生重要影响。采用偶关联函数和键对分析技术对原子局域团簇结构进行分析,并考察了冷却过程中原子势能随温度的变化,比较了Au的微观结构转变与能量变化的对应关系,从能量转化的角度对冷却过程中Au的结构变化进行了说明。     

Synthesis of nanocrystalline calcium phosphate in microemulsion--effect of nature of surfactants

Nanosized calcium phosphate (CP) powders have been synthesized by an inverse microemulsion system using kerosene as the oil phase, a cationic surfactant Aliquat 336, a non-ionic surfactant Tween 20 and their mixture and aqueous solutions of calcium nitrate tetrahydrate and biammonium hydrogen phosphate as the water phase. It has been found that the nature of surfactants played an important role to regulate the size and morphologies of the calcium phosphate nanoparticles. The cationic surfactant Aliquat 336 has been found to regulate the nucleation and crystal growth. The synthesized powders have been comprehensively characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), powder X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Our results show that the brushite (DCPD) is the major phase comprising the calcium phosphate nanoparticles. In mixed surfactants mediated system a morphological controlled highly crystalline particles have been synthesized. Further, the role of Aliquat 336 has been established and a plausible synthetic mechanism has been proposed.     

Research of Fluorination Process of Rutile Concentrate

The brief review of industrial technologies of titanium-containing concentrates processing has been carried out. Drawbacks of the existing titanium manufacture schemes are shown and the necessity of the essentially new fluoride technologies development has been proved. The reactions proceeding during the fluorination of rutile concentrate with element fluoride are described in the given work. The thermodynamic research of the process has been carried using ASTRA software. Dependence of mass concentration change of titanium tetrafluoride has been investigated in products of reaction on the temperature of the process, and the choice of optimum excess of fluoride has been proved.     

The influence of the concentration and size of silver nanoparticles on the conductivity of ring-shaped deposits resulting from evaporation of colloidal solution droplets

The conductivity of ring-shaped deposits formed at the periphery of evaporating droplets of silver nanoparticle colloidal solutions has been studied. The dependence of the resistance of the ring-shaped deposits on nanoparticle size has been shown to exhibit a percolation transition. The specific conductivity of the deposits has been estimated in relation to their geometric shapes. The conductivity has been established to nonmonotonically depend on nanoparticle sizes. It has been noted that, in rather strong fields, the conductivity of the composite layers dramatically increases after some induction period. The X-ray spectra of silver have been revealed to alter for samples the conductivity of which has increased under the action of an external electric field.     

Specific Features of Photolysis of Optical Bleachers of Various Chemical Nature in a Polyvinyl Alcohol Matrix

The photophysical and photochemical parameters of organic luminophores used as optical bleachers in a polyvinyl alcohol matrix at room temperature have been determined and optimal conditions for their estimation have been found. The effect of organic and inorganic additives on the fluorescence and photodegradation processes of optical bleachers has been studied and recommendations for photostabilization of the latter at a minimum sacrifice in their quantitative and qualitative consumers' characteristics have been made. The effect of additives of the degradation pathways of optical bleachers under actinic light has been characterized.     

Optical, morphological and structural characterization of Langmuir-Schaefer films of a functionalized copper phthalocyanine

Langmuir-Schaefer (LS) films of copper(II) tetrakis-(isoprpoxy-carbonyl)-phthalocyanine (TiPCuPc) have been deposited onto various solid supports. Its floating film have been characterized at the air-water interface by means of Brewster Angle Microscopy and Langmuir curves. Vibrational modes of multilayer transferred LS film have been studied by Raman spectroscopy and the optical parameters (refractive index n and extinction coefficient k) have been determined in the visible range of the electromagnetic spectrum. Linearly polarized light absorbance measurements have been performed at room temperature in the 400-800 nm spectral range and the average orientation of the phthalocyanine rings have been estimated. Transmission electron microscopy has been also used to characterize the morphological properties of the LS film and a close packed arrangement of the deposited molecules has been observed.