The formation of nickel(II) chloride ammine complexes in the pores of modified fibers of cellulose cloth

A sorbent was synthesized as a cellulose cloth, the fibers of which have nanopores with walls made of cellulose chains and ethanol cyclams. The formation of (NH₄)₂[NiL(NH₃)₂Cl₂] complexes where L^2– is the CH–(O^–)–CH–(O^–) glucopyranose group was established by chemical analysis and IR and UV/Vis spectroscopy. Using small-angle X-ray scattering and measurement of the partial free space and adsorption capacity, the complex formation in the [Ni(NH₃)₆]Cl₂ concentration range of up to 0.43 mol/L was found to occur in nanopores with the sorption constant K _sorb = 15.8. The limiting content of the complexes is 2.63 mmol/g and their effective radius is 0.45 nm. In the concentration range of 0.43–0.91 mol/L, the complexation occurs on the fiber surface, K _sorb = 1.85. The effective radius of the complexes is 0.5 nm.     

1H and 13C hyperfine coupling constants of the tryptophanyl cation radical in aqueous solution from microsecond time-resolved CIDNP

Relative values of the 1H and 13C isotropic hyperfine couplings in the cationic oxidized tryptophan radical TrpH*+ in aqueous solution are determined. The data are obtained from the photo-CIDNP (chemically induced dynamic nuclear polarization) enhancements observed in the microsecond time-resolved NMR spectra of the diamagnetic products of photochemical reactions in which TrpH*+ is a transient intermediate. The method is validated using the tyrosyl neutral radical Tyr*, whose 1H and 13C hyperfine couplings have previously been determined by electron paramagnetic resonance spectroscopy. Good agreement is found with hyperfine coupling constants for TrpH*+ calculated using density functional theory methods but only if water molecules are explicitly included in the calculation.     

Analysis of the interrelation between the processes of polarization and microstructuring in a magnetic fluid layer

The results of examining and analyzing the interrelation between the processes of polarization and structuring in magnetic fluid microlayers under the influence of the temperature, external electric and magnetic fields, and variations in the structure and amount of stabilizer have been presented.

     

Impurity photovoltaic effect in <Emphasis Type="Italic">p-i-n</Emphasis> structures of undoped GaAs

Photo-emf in the range hv = 0.76 ? 1.35 eV was found in p-i-n structures produced from undoped GaAs crystals with known parameters; the current sensitivities in the impurity and intrinsic (hv > 1.35 eV) regions were comparable. It was proven that the impurity photovoltaic effect results from EL2 and EL3 structural defects creating deep donor levels in the forbidden zone. Calculations were performed that justified the possibility of observing this effect on the investigated structures.     

Structure of Ir-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> coatings obtained by chemical vapor deposition in the hydrogen atmosphere

Chemical vapor deposition is used to obtain Ir and Ir-Al₂O₃ coatings with a thickness of up to 5 μm and growth rate of 2.5 μm/h on steel substrates previously covered with an alumina layer. Tris-acetylacetonates of Ir(III) and Al(III) are used as precursors. The deposition process is carried out at the atmospheric pressure in the presence of hydrogen. The coatings obtained are studied by X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy. A dependence of the structure and composition of coatings on their preparation conditions is found.     

Conducting polyaniline prepared by the laccase-catalyzed method in a water dispersion of sodium dodecylbenzenesulfonate micellar solution

In the present work, physico-chemical properties of conducting polyaniline (PANI) prepared by laccase-catalyzed oxidative polymerization in water dispersions of sodium dodecylbenzenesulfonate micellar solutions were studied. The polymer was characterized using FTIR spectroscopy, cyclic voltammetry, termogravimetry, transmission electron microscopy, and electron diffraction. The antistatic properties of the obtained polyaniline were also studied.     

Correction of the readings of albedo dosimeters at the MC400 LNR cyclotron with the use of the spherical albedo system and comparison with other correction methods

The results of correcting the readings of DVGN-01 albedo dosimeters behind the shielding of the MC400 cyclotron at the Laboratory of Nuclear Reactions (LNR) with the use of the spherical albedo system are presented. The formulas approximating the dependences of correction coefficients used to correct the readings on the hardness parameters of low-energy neutron spectra were obtained based on these results and the results of earlier studies. Neutron spectra were measured at three points behind the MC400 shielding, and the correction coefficients for DVGN-01 were calculated based on these spectra. It was demonstrated that these coefficients agree well with the coefficients obtained with the use of the spherical albedo system. This suggests that the obtained correction coefficient values are accurate. The recommended correction coefficient values to be used in the individual dosimetric control at LNR were specified based on the results of the present study and the data given in other papers.     

Photooxidation of Histidine by 3,3′,4,4′-Benzophenone Tetracarboxylic Acid in Aqueous Solution: Time-Resolved and Field-Dependent CIDNP Study

The photooxidation reaction between 3,3′,4,4′-benzophenone tetracarboxylic acid (TCBP) and l-histidine (His) has been investigated in neutral aqueous solution using the technique of chemically induced dynamic nuclear polarization (CIDNP). Relative values of ¹³C isotropic hyperfine couplings in the TCBP and His radicals were obtained from the ¹³C-time-resolved CIDNP spectrum, recorded during the photoreaction of TCBP with His at natural abundance of the magnetic isotope ¹³C. Good agreement was found for the hyperfine coupling constants of the TCBP ketyl radical calculated using methods of density functional theory, and those obtained from the ¹³C-time-resolved CIDNP spectrum. The mechanism of the quenching reaction of triplet-excited TCBP by His in neutral aqueous solution was established. ¹H CIDNP field dependencies for the photoreaction of TCBP with His were obtained and the g-factor of the histidyl radical was found.     

Investigation of self-action effects of magnetostatic waves in ferromagnetic structures in terms of the system of Schr?dinger equations with coherent or incoherent coupling

The effect of coupling on the nonlinear dynamics of magnetostatic wave pulses in layered ferromagnetic structures consisting of two ferromagnetic films has been investigated using the numerical solution to the systems of coherent and incoherent nonlinear Schr?dinger equations. The conditions of formation and the possibility of controlling such effects as nonlinear beats, instability of fast solitons, trapping, and tracking have been discussed. The main features of these effects have been analyzed and the applicability of coupled structures to control the formation of nonlinear pulses of magnetostatic waves has been considered.