Dissolution Kinetics of Nickel(II) Hydroxide in a Mixed Ammonia–Carbonate Solution

Theoretical Foundations of Chemical Engineering - The reaction of nickel(II) hydroxide and a mixed ammonia–carbonate solution to form nickel(II) aqua–ammonia complexes is studied in the...     

On manifestation & physics of the Kurdjumov and spillover effects in carbon nanostructures,under intercalation of high density hydrogen

Abstract

Some experimental evidences and the physics (thermodynamics) of the nanoscale self-intercalation of high-density gaseous molecular hydrogen (ρ?≈?0.045?g/cm³, T?≈?300?K) into surface nanoclusters in highly oriented pyrolytic graphite and epitaxial graphene, as well as the nanoscale self-intercalation of high density solid molecular hydrogen (ρ?≈?0.5?g/cm³, T?≈?300?K, the compressed pressure ～ 0.5 Mbar) into graphite nanofibers are considered, with regard to the problem of compact and efficient hydrogen on-board storage and other clean energy applications. Perspectives of further developments of these results are considered, as well.     

Photophysical properties of indolo[3,2-b]carbazoles as a promising class of optoelectronic materials

The photophysical properties of new synthesized indolocarbazoles, i.e., indolo[3,2-b]carbazole and its derivatives, have been comparatively analyzed. It is shown that their photosensitivity (total photosensitivity to (5–8) × 10⁻² (lx s)⁻¹, spectral photosensitivity ∼10⁵ cm² J⁻¹, and free carrier photogeneration quantum yield of 0.1) and transport (effective mobility in 5,11-dioctyl indolo[3,2-b]carbazole is more than 10⁻⁵ cm²/(V s)) parameters significantly exceed those of pentacene, which, among molecular media (organic crystals), exhibits the highest carrier photogeneration quantum yields. The high photoluminescence intensity of synthesized indolo[3,2-b]carbazole derivatives shows promise for their applicability in electroluminescent devices.     

LPCVD-silicon oxynitride films: interface properties

The interface properties of silicon oxynitride films prepared by low-pressure chemical vapor deposition at a temperature of 860 ° C have been investigated analyzing the capacitance–voltage and ac conductance–voltage characteristics of the metal-SiO_xN_y-silicon capacitors. Consistent results for the interface trap density have been obtained from single frequency ac conductance technique, approximation C–V method and from the interface density spectrum. The post-deposition annealing results in an improvement of the interface charge properties. The contribution of the interface traps to the estimation of the fixed oxide charge has been discussed which is important for the threshold voltage control in MOS devices.     

New catalytic processes for a sustainable chemistry of cellulose production from wood biomass

The present paper describes the results of studies directed to novel catalytic processes design for the environmentally friendly production of cellulose. The new delignification catalyst which is produced by chemical interaction of elemental sulfur with hydrazine in superbase medium was used for the improvement of efficiency and ecological purity of the conventional pulping process. This catalyst reduces the concentration of polysulfides in pulping liquor and the yield of side sulfur-containing compounds (by 1.5 times). The processes of wood delignification with sulfur-free reagents based on catalytic pulping with acetic acid and hydrogen peroxide and on the delignification of steam-activated wood with NaOH or Na₂CO₃ solutions have prospects for the environmentally benign production of cellulose. The new catalytic process of vanillin production by oxidation of lignosulfonates with molecular oxygen was described.     

The determination of diffusion coefficients of counter ion in an ion exchange membrane using electrical conductivity measurement

Electrical conductivity experiments were carried out in a bi-ionic (chloride-nitrate) electrolyte with and without a permselective anion exchange membrane (ACS of Tokuyama Soda) at variable chloride/nitrate concentration. Diffusion coefficients of counter ions (Cl⁻ and NO₃⁻) in the membrane were determined from a mathematical model based on the Nernst-Planck diffusion-convection theory: the mean diffusion coefficients in the membrane were obtained by fitting the (conductivity vs. concentration) curves with the Nernst-Planck equation.     

Reflection electron-energy-loss spectroscopy of Fe<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Si<Subscript>1 − <Emphasis Type="Italic">x</Emphasis></Subscript> thin films

The values of the product of the inelastic mean free path and the differential cross section for inelastic scattering of electrons have been determined from the reflection electron-energy-loss spectra of thin films of the Fe _x Si_{1 − x} system (0 ≤ x ≤ 1). A new approach to the quantitative analysis of components in such composite media is proposed.     

Synthesis,characterization, and structure-property relationships of aromatic polyimides containing 4,4′-diaminotriphenylmethane

This work reports two series of structurally different aromatic polyimides based on 4,4´-diaminodiphenylmethane (DPM) and 4,4´-diaminotriphenylmethane (TPM) and three commercial dianhydrides. All TPM-based polyimides formed membranes due to their high molecular weight (inherent viscosities ~0.93–1.14 dl/g), they exhibited high thermal stability (5 %: 490–544 °C), glass transition temperatures between 269 and 293 °C, and reasonable mechanical properties. The incorporation of pendant phenyl moieties in the TPM-based polyimides has a strong effect producing an improvement in solubility, thermal stability, density and gas permeability coefficient in comparison with DPM-based polyimides. The most interesting polyimide TPM-6FDA, containing phenyl and trifluoromethyl as bulky pendant groups, showed higher gas permeability coefficient for CO₂ (23.73 Barrer) and the best ideal selectivity to the gas pair CO₂/CH₄ (α = 28.93).     

Properties of the regulatory subunit of cAMP-dependent protein kinase type II from human brain

The regulatory subunit type II (RII) of cAMP-dependent protein kinase purified from human brain was represented by two proteins with apparent molecular masses of 51-52 kD and 54 kD. Dephosphorylation of human RII containing 3 mol phosphate/mol protein did not change the electrophoretic pattern. One-dimensional peptide mapping of 51-52 kD and 54 kD proteins after digestion with St. aureus V8 protease evidenced to their being distinct proteins. The data obtained permit to assume that human RII of neural type is represented by two isoforms.