排序方式: 共有33条查询结果,搜索用时 31 毫秒
1.
L. I. Kravets A. B. Gilman M. Yu. Yablokov V. M. Elinson B. Mitu G. Dinescu 《Russian Journal of Electrochemistry》2013,49(7):680-692
The surface and electrochemical properties of polypropylene track membrane treated by plasma of nitrogen, air, and oxygen are studied. The effect of the plasma-forming gas composition on the surface morphology is considered. The membrane surface microrelief formed during the gas-discharge etching is found to change. Moreover, the non-polymerizing gas plasma treatment induces oxidation of the membrane surface layer and generates oxygen-containing functional groups, mostly carbonyl and carboxyl. The higher membrane roughness and its hydrophilization is shown to lead to its better wettability. In addition, the presence of polar groups in the membrane surface layer modifies its hydrodynamic and electrochemical properties so that water permeability and conductivity of modified membranes increase. 相似文献
2.
Effect of denaturation of DNA on the molecular organization of a fluorescent dye in ultra thin films
Acridine Orange (AO) forms H-dimer in solid state and in ultra thin films. However, H dimer of AO reduces its efficiency as a usefull material for fluorescence probe. In the present work detailed investigations has been done on the interaction of AO with different forms of DNA in order to check the effectiveness in controlling the dimeric sites of AO in the Layer by Layer (LbL) self assembled film. It was found that single stranded DNA (ssDNA) is most effective than the dsDNA and coil-shaped DNA in controlling the dimeric sites of AO in LbL film. 相似文献
3.
Priya Budhani Sayed Aftab Iqbal Suman Malik Mamta Bhattacharya Liviu Mitu 《Journal of Saudi Chemical Society》2010,14(3):281-285
The present paper deals with the synthesis and characterization of Schiff base complexes of pyrazinamide an antitubercular drug. Metals selected for complexation are copper, silver, gold, zinc, mercury, iron and cobalt. The complexes have been suitably synthesized and isolated in pure powdered form. Analytical data agrees with the compositions M(L), M′(L)2 and M″(L)2·2H2O, respectively where M = Ag, M′ = Cu, Au, Zn and Hg and M″ = Fe and Co, ligand metal ratios were also confirmed by monovariation method and Job’s method of continuous variation. Molar conductance values suggest the non ionic nature of the complexes. The tentative structure assigned to the complexes on the basis of stoichiometry and analytical data were further supported by spectral studies viz; IR, NMR, magnetic susceptibility and electronic spectra. A preliminary attempt has also been made to compare the potencies of metal complexes with parent drug. The Cu and Ag complexes are giving encouraging results. Particle size studies further suggest that the drug molecule undergoes reduction in size on complexation. 相似文献
4.
Kravets L. I. Dmitriev S. N. Satulu V. Mitu B. Dinescu G. 《Russian Journal of Applied Chemistry》2010,83(9):1628-1635
Structure and electrotransport properties of poly(ethylene terephthalate) track membranes modified in pyrrole plasma were
studied. Physicochemical aspects of the conductivity asymmetry arising from the contact of two layers with functional groups
of different nature and from changes in the pore geometry are discussed. 相似文献
5.
Dumitru?OanceaEmail author Valentin?Munteanu Domnina?Razus Maria?Mitu 《Journal of Thermal Analysis and Calorimetry》2011,103(3):911-916
The ignition of catalytic combustion of the stoichiometric propane/air mixture on an isothermally heated platinum wire in
different experimental conditions of total pressure and wire temperature is studied and discussed on the basis of a simplified
kinetic model. The platinum wire is heated electrically with a specially designed power supply, which ensures a quasi-rectangular
profile of its temperature. The ignition process is monitored by measuring the input power required to maintain a constant
temperature of the wire during an exothermic catalytic reaction. The difference between the input powers recorded in air and
in a fuel/air mixture, for the same wire temperature and gas total pressure, allows the elimination of the heat transferred
to surroundings and conversion of the results into the catalytic reaction rate r
R versus time curves of S-shaped form, illustrating the transition from kinetic to diffusion regime. The curve can be used
to evaluate the ignition delay, as reported previously and also to fit different models to the data. The quasi-exponential
increase of the isothermal reaction rate during the early stages of the process can be rationalized on the basis of a simplified
kinetic model implying the multiplication of the adsorbed active intermediates. The adopted hypotheses allow the derivation
of an analytical solution for the catalytic reaction rate before and during the ignition process, without diffusion limitations. 相似文献
6.
L. I. Kravets V. A. Altynov M. Yu. Yablokov A. B. Gilman V. Satulu B. Mitu G. Dinescu 《High Energy Chemistry》2018,52(4):335-342
The morphology and chemical structure of nanosized polytetrafluoroethylene films deposited on the surface of track-etched poly(ethylene terephthalate) membranes by means of radiofrequency magnetron sputtering and electron-beam sputtering of the polymer in a vacuum have been studied using atomic force microscopy and X-ray photoelectron spectroscopy. It has been established that the morphology of films formed with the use of these coating techniques varies considerably. This is due to the size of the deposited polymer particles. The particles formed by the electron-beam sputtering of polytetrafluoroethylene are larger than those produced by magnetron sputtering of the polymer. It has been shown that the chemical composition of the films deposited by electron-beam sputtering in a vacuum is more in line with the composition and structure of the initial polymer than the films obtained by radiofrequency magnetron sputtering. 相似文献
7.
Maria Mitu Domnina Razus Dumitru Oancea 《Journal of Thermal Analysis and Calorimetry》2018,131(1):175-181
The present work aims to investigate several kinetic aspects of catalytic combustion of the stoichiometric propane–air mixture on a platinum wire in the presence of progressive CO2 dilution, using a micro-calorimetric method. The method allowed the determination of the induction periods and of the reaction rates during transient and steady-state regimes at different initial pressures P 0 (10–101 kPa), wire temperatures T w (470–575 K) and gas-phase composition. The kinetic parameters were evaluated from regression analysis using empirical and mechanistic models. The dilution with CO2 of the stoichiometric propane–air mixture (4.02% propane) was 10, 20, 30, 40, 50%. For additions equal to or greater than 23%, the gaseous system is outside the flammability limits reported in the literature. The kinetic characteristics of the catalytic combustion remain similar for the whole range, even for 50% CO2 addition when the propane concentration in mixture diminishes to 2%, a concentration smaller than the lower explosion limit in air in normal conditions. 相似文献
8.
9.
N. Ramana R. Jeyamurugan B. Rajkapoor L. Mitu 《Journal of the Iranian Chemical Society》2010,7(4):917-933
Novel copper(II) and zinc(II) complexes of the type [ML(dppz)]Cl2, [L = Schiff base derived from the condensation of 3-(3- phenyl-allylidene)-pentane-2,4-dione and para-substituted aniline; X = -NO2 (L1), -H (L2), -OH (L3) and -OCH3 (L4); dppz = dipyrido (3,2-a:2′, 3′ -c)phenazine] were synthesized and characterized by various analytical and spectral techniques. The physicochemical studies and spectral data indicated that all the complexes were monomeric and cationic with square-planar geometry. Spectroscopic data and viscosity measurements showed that the complexes intercalated to DNA with large binding constants. The substituted groups such as -NO2, -H, -OH and -OCH3 in aniline moiety influenced the observed trend in the redox potentials of the complexes. The peak potential separation and formal potential of complexes were independent of sweep rate or scan rate (ν) indicating a quasireversible one-electron redox process. In all the cases, i p was linear function of ν1/2, as expected for diffusion controlled process, and i pa/i pc ≈ 1 at all sweep rates. It was found that the decrease in i pc was due to the higher binding of copper complexes and slowly diffusing DNA. In the presence of a reducing agent like 3-mercaptopropionic acid (MPA), the chemical nuclease activity order of the copper complexes under dark reaction condition was -NO2 > -H > -OH > -OCH3. The hydrolytic cleavage of DNA by the zinc complexes was supported by the evidence from free radical quenching and T4 ligase ligation. 相似文献
10.
The characteristics of carbonic materials obtained by downstream deposition in a low pressure argon plasma beam injected with acetylene are reported. The influence of substrate temperature, presence of Ni catalyst and hydrogen in gas composition on the material properties is described. By increasing the substrate temperature, an enhanced order in the material is revealed by Raman spectroscopy, while FTIR measurements show a decreasing of the hydrogen content and the disappearing of sp1 hybridized carbon in the deposit. The SEM and Raman investigation show a clear tendency of crystalline phases formation when hydrogen is assisting the deposition. 相似文献