Ethanol loading in an inductively coupled plasma

Changes to the fundamental and analytical parameters of a plasma have been investigated when ethanol has been added to aqueous or organic solutions. Excitation temperature, electron number density, and intensity of the H(alpha) line increased when ethanol has been added to aqueous solutions, while an electron density decrease and signal reduction have been found when ethanol has been added to xylene. The sensitivity has been improved for all ethanol concentrations when water has been the solvent, but the reverse has been found for xylene solutions.     

Polymers from 12-hydroxymethyltetrahydroabietic acid and its vinyl and acrylate esters

12-Hydroxymethyltetrahydroabietic acid has been homopolymerized by melt condensation and homopolyester has been obtained. Vinyl 12-hydroxymethyltetrahydroabietate has been prepared from 12-hydroxymethyltetrahydroabietic acid by vinyl interchange procedure with vinyl acetate, and has been homopolymerized, copolymerized with vinyl chloride, vinyl acetate, and terpolymerized with styrene and acrylonitrile. The acrylate ester of 12-hydroxymethyltetrahydroabietic acid also has been prepared from 12-hydroxymethyltetrahydroabietic acid and acrylyl chloride. The acrylate thus obtained has been homopolymerized and copolymerized with vinyl chloride and vinyl acetate. Polymers thus obtained have been characterized.     

Overpressured thin-layer chromatography

The properties, apparatus and applications of overpressured thin-layer chromatography (OPTLC) have been reviewed. In the Introduction planar chromatography has been briefly characterized, with particular attention to TLC. The general properties of OPTLC and methods of development of chromatograms in this technique have been then given. The construction of chambers and equipment for OPTLC has been described, paying attention to two-dimensional columns. The properties of chambers for OPTLC have been characterized considering the flow of eluent, sorbent-eluent interactions and the efficiency of various systems. OPTLC, TLC and HPTLC have been compared and also a comparison between OPTLC with a constant (linear) eluent flow-rate and with a decreasing eluent flow-rate has been made. Analytical applications of OPTLC have been described and examples of separations of mixtures have been given.     

Facile synthesis methodology and characterization studies of silica-decorated hybridized anisotropic nanotubes and nanosheets

Carbonaceous nanomaterials and their derivatives have been inspired tremendous enthusiasm in the scientific community. They have been excogitated as the encouraging attributes and the qualified dispersed phase to develop multi-functional composites. Particularly, graphene and carbon nanotube (anisotropic fillers) have gained substantial research interest owing to their promising characteristics. This highlights an innovative technique to synthesize hybridized nanotube and nanosheet. Initially, parent materials have been synthesized: The pristine CNT has been modified by acid mixture solution, and reduced graphene oxide has been prepared by chemical reduction method. Henceforth, the self-assembly in situ sol–gel technique has been endorsed here. The synthesized nanohybrids have been characterized by different spectroscopic techniques: FTIR, Raman, UV, and XPS to confirm the attachment of multifunctionalities; meanwhile, the composition and stability have been investigated from XRD and TGA plots. The magnitude of surface charge and particle size distribution have been evaluated for the parent and hybridized products; further, morphology of all the samples has been authenticated from FESEM and TEM.     

Phase structure of silanol-modified ethylene-vinyl acetate copolymers

For (ethylene-vinyl acetate copolymer)-tetraethoxysilane and (ethylene-vinyl acetate copolymer)-polydimethylsiloxane systems, the solubility of components has been studied in a wide range of temperatures and compositions. Phase diagrams have been constructed, pair interaction parameters have been calculated, and diffusion coefficients and activation energies of diffusion have been estimated. The temperature and concentration ranges of a change in solubility related to chemical interactions between the components have been revealed, and the structure of the modified copolymers has been studied. On the basis of the kinetic data on the movement of isoconcentration planes in diffusion zones of component mixing, time intervals corresponding to the onset of the chemical reaction between the components have been determined and the apparent activation energies of the process have been computed. Complex-shaped binodal and boundary curves have been interpreted within the framework of the classical Flory-Huggins theory.     

Ethanol loading in an inductively coupled plasma

Changes to the fundamental and analytical parameters of a plasma have been investigated when ethanol has been added to aqueous or organic solutions. Excitation temperature, electron number density, and intensity of the H line increased when ethanol has been added to aqueous solutions, while an electron density decrease and signal reduction have been found when ethanol has been added to xylene. The sensitivity has been improved for all ethanol concentrations when water has been the solvent, but the reverse has been found for xylene solutions.     

Electron microtomography: A new method for studying the spatial structure of catalysts

The spatial arrangement of active component (Pt) particles on the surface of a support (Sibunit globule) has been studied by bright-field electron tomography. A tomographic attachment for a standard specimen holder and tomographic grids have been designed. The tomographic procedure has been refined, and adequate tilt series alignment and tomographic reconstruction algorithms have been chosen. The 3D distribution of the active component in the catalyst grain has been studied: particles hidden in micropores have been directly observed, and the size of the pores connecting internal cavities with the exterior has been estimated.     

Multibiosensor based on enzyme inhibition analysis for determination of different toxic substances

An original concept of an enzyme multibiosensor for determination of toxic substances based on enzyme inhibition analysis has been proposed and its main performances have been analysed. For the development of this multibiosensor, two types of transducers such as potentiometric pH-sensitive field-effect transistors and conductometric thin-films interdigitated electrodes, and three enzymes, namely urease, acetylcholinesterase and butyrylcholinesterase have been used. The experimental data have been treated by multivariate correspondence analysis. A complete procedure for a simultaneous determination of some heavy metal ions and pesticides has been proposed and its advantages have been discussed.     

Action of trypsin on a nucleoprotein from sturgeon gonads

A nucleoprotein has been isolated from the gonads of the Caspian sturgeon and its composition has been determined. It has been shown that it contains 55% of DNA, 2% of RNA, 36% of protamines, and about 7% of nonprotamine proteins of nonbasic nature. The nucleoprotein has been hydrolyzed with trypsin, and the amino acid compositions of some hydrolysis products have been studied. On the basis of the results obtained, the hypothesis has been put forward of a possible linkage of the DNA with the basic proteins. It has been shown that protamines react with the DNA through the basic amino acid residues located at various regions of their molecules.     

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.     

快原子轰击质谱及其在金属有机配合物研究中的应用

本文介绍FAB质谱的原理、功能和优点。综述了FAB机理,讨论了影响FAB谱的因素。归纳了FAB法在金属有机配合物研究中的应用。     

Synthesis, structure, and properties of the Cu(II) coordination compounds with the pyruvic acid nicotinoyl and isonicotinoyl hydrazones

New coordination compounds of Cu(II) and hydrazones of nicotinic and isonicotinic acids have been prepared. The complexes isolated have been studied by elemental analysis, thermogravimetric analysis, magnetic susceptibility measurements, IR, diffuse reflectance, and EXAFS spectroscopy. The geometry of the compounds has been determined and the type of the ligands coordination has been revealed. Antibacterial activity of the complexes has been studied.     

Development and in situ synthesis of monolithic stationary phases for electrochromatographic separations

Organic monolithic stationary phases have been synthesized in UV-transparent fused-silica capillaries, which have been used as test format of microfabricated device channels. The columns have been prepared by in situ polymerization of butyl acrylate, lauryl acrylate, 1,3-butanediol diacrylate, and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) in a ternary porogenic solvent. The resulting stationary phases have been tested in capillary electrochromatography and exhibited reversed-phase chromatography behavior toward neutral solutes. Van Deemter plots of phenylureas and polycyclic aromatic hydrocarbons, selected as model analytes, have been determined to study the influence of various polymerization and separation parameters on properties of the monoliths. The amount of AMPS and the nature of monomers in the polymerization solution have been thus adjusted. It has been observed that the ionic strength of the mobile phase may affect significantly the efficiency of the separation. The effect of the percentage of acetonitrile in the mobile phase on efficiency and permeability of the organic monoliths has also been investigated. Efficiencies greater than 300,000 plates/m have been obtained with the test compounds. Stability and reproducibility have been extensively studied.     

Structural defects in poly(vinylchloride)—III. Degradation of vinyl chloride-phenylacetylene copolymers in solution

Vinylchloride-phenylacetylene copolymers have been prepared and characterized. A known amount of defined defect sites, viz. double bonds, has been introduced into the main chain of the polymer. Thermal degradation behaviour of the copolymers has been studied in trichlorobenzene solution. A strong dependence of the kinetics of dehydrochlorination and polyene formation on the defect concentration has been found. Rate constants and activation parameters have been determined. The effects of different structures have been compared.     

Polymers from 12 α-hydroxymethylabiet-7,8-enoic acid and vinyl 12 α-hydroxymethylabiet-7,8-enoate

12 α-Hydroxymethylabiet-7,8-enoic acid has been homopolymerized by melt condensation, and a partially crystalline polyester has been obtained. Vinyl 12 α-hydroxymethylabiet-7,8-enoate has been prepared from 12 α-hydroxymethylabiet-7,8-enoic acid by vinyl interchange with vinyl acetate and has been homopolymerized, copolymerized with vinyl chloride, vinyl acetate, butadiene, and acrylonitrile, and terpolymerized with styrene and acrylonitrile. Polymers thus obtained have been characterized.     

Alpha-cyclodextrin functionalized CdS nanocrystals for fabrication of 2/3 D assemblies

Different types of cyclodextrins (CDs) have been tested as mediators for the water phase transfer of organic-capped CdS nanocrystals (NCs), and alphaCD has been demonstrated to be the most effective system. The formation of a complex based on alphaCDs and colloidal NCs has been considered to be responsible for the phase transfer process and extensively investigated by optical, structural, and calorimetric measurements, as a function of the experimental parameters (pH and NC and CD concentration). A mechanism for the complexation phenomena has been suggested. The fabrication of 2/3 D supramolecular architectures has been proposed according to two different strategies. First, a layer-by-layer procedure has been used to obtain multilayered structures where polyelectrolyte layers have been intercalated with negatively charged alphaCD-CdS NC complexes by exploiting electrostatic interaction between polyelectrolyte and cyclodextrin OH groups. Second, a monolayer of CdS NCs has been deposited onto a self-assembled monolayer of sulfated CDs, thus combining the use of an electrostatic-force-based approach and host-guest chemistry. The important role played by host-guest interactions has then been revealed.     

On temperature- and space-dimension dependent matter agglomerations in a mature growing stage

Model matter agglomerations, with temperature as leading control parameter, have been considered, and some of their characteristics have been studied. The primary interest has been focused on the grain volume fluctuations, the magnitude of which readily differentiates between two commonly encountered types of matter agglomeration/aggregation processes, observed roughly for high- and low-density matter organizations. The two distinguished types of matter arrangements have been described through the (entropic) potential driving the system. The impact of the potential type on the character of matter agglomeration has been studied, preferentially for (low-density) matter aggregation for which a logarithmic measure of its speed has been proposed. A common matter diffusion as well as mechanical relaxation picture, emerging during the mature growing stage, has been drawn using a phenomenological line of argumentation. Applications, mostly towards obtaining soft agglomerates or so-called jammed materials, have been mentioned.     

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.     

Transformation of 1,1-Dichloro-2,2-bis(4-nitrophenyl)ethene in the Reaction with Nitrite Ion in Polar Aprotic Solvents

The reaction of 1,1-dichloro-2,2-bis(4-nitrophenyl)ethene with sodium nitrite in polar aprotic solvents has been studied. Products of the reaction have been identified, and effects of different factors, including reactant dissociation and solvation, on the reaction rate constants have been analyzed. Thermodynamic parameters of the reaction have been determined, the multistep process has been simulated by quantum chemical calculations, and a plausible mechanism has been proposed.     

Copper ferrocyanide — polyurethane foam as a composite ion exchanger for removal of radioactive cesium

A method has been developed for the removal of cesium from the aqueous radioactive waste using a composite ion-exchanger consisting of Copper-Ferrocyanide Powder (CFC) and Polyurethane (PU) Foam. Polyvinyl acetate has been used as a binder in the preparation of CFC-PU foam. The physical properties of CFC such as density, surface area, IR stretching frequency and lattice parameters have been evaluated and also its potassium and copper(II) content have been estimated. Optimization of loading of CFC on PU foam has been studied. The CFC-PU was viewed under microscope to find out the homogeneity of distribution. Exchange capacities of the CFC-PU foam in different media have been determined and column studies have been carried out. Studies have been undertaken on extraction of cesium from CFC foam and also on digestion of spent CFC-PU foam and immobilization of digested solution in cement matrix. The cement matrices have been characterized with respect to density, bio-resistance and leaching resistance.