Spectrophotometric determination of association equilibrium constants of certain phenol substitution derivatives with triethylamine

A spectrophotometric technique was used to determine the association equilibrium constants of phenol, o-isopropylphenol, p-tert-butylphenol, 3,4-, 2,5-, 2, 6-dimethylphenols, and thymol with triethylamine (in an n-heptane medium). The ultraviolet spectra recorded serve as proof of the formation of a hydrogen bond between the hydrogen atoms of the hydroxyl group and the nitrogen atom of triethylamine in these systems (phenol-triethylamine-n-heptane).In conclusion we express out sincere thanks to Prof. V. M. Tatevskii for his interest and valuable advice.     

Magnetic moment relaxation of a shallow acceptor center in heavily doped silicon

Results of studying the temperature dependence of the residual polarization of negative muons in crystalline silicon with germanium (9×10 ¹⁹ cm ^?3 ) and boron (4.1×10 ¹⁸ , 1.34×10 ¹⁹ , and 4.9×10 ¹⁹ cm ^?3 ) impurities are presented. It is found that, similarly to n-and p-type silicon samples with impurity concentrations up to ～10 ¹⁷ cm ^?3 , the relaxation rate ν of the magnetic moment of a _μ Al acceptor in silicon with a high impurity concentration of germanium (9×10 ¹⁹ cm ^?3 ) depends on temperature as ν～T ^q , q≈3 at T=(5–30) K. An increase in the absolute value of the relaxation rate and a weakening of its temperature dependence are observed in samples of degenerate silicon in the given temperature range. Based on the experimental data obtained, the conclusion is made that the spin-exchange scattering of free charge carriers makes a significant contribution to the magnetic moment relaxation of a shallow acceptor center in degenerate silicon at T?30 K. Estimates are obtained for the effective cross section of the spin-exchange scattering of holes (σ _h ) and electrons (σ _e ) from an Al acceptor center in Si: σ _h ～10^?13 cm² and σ _e ～8×10^?15 cm² at the acceptor (donor) impurity concentration n _a (n _d )～4×10¹⁸ cm^?3.     

Measurements of the magnetic moment of the negative muon in the bound state in various atoms

The magnetic moment of the negative muon in the 1s state was measured in carbon, oxygen, magnesium, silicon, sulfur, and zinc. The attained precision of measurements allowed the dependence of the relativistic correction to the magnetic moment of the bound muon on the charge of the nucleus to be verified.     

Deposition of thin electroplated Cd-Se layers

Cadmium-selenium alloys were electrodeposited from a sulfuric acid electrolyte. The effect of the H₂SeO₃, CdSO₄, and sulfuric acid concentrations, current density, and temperature on the composition and quality of cathode deposits was studied.     

Synthesis of halomethyl-substituted bicyclo[2.2.1]hept-2-yl(meth)acrylates

Russian Journal of Applied Chemistry - Bicyclic esters, which are reactive monomers for the synthesis of new polymeric products and also of organic compounds, were synthesized by the reaction of...     

Influence of lanthanum concentration on acid and catalytic properties of H-pentasil in the μ-xylene isomerization reaction

Russian Journal of Applied Chemistry - Acid and catalytic properties of pentasil-type lanthanum-containing zeolites in the μ-xylene isomerization reaction were studied.     

A fundamental solution to the Cauchy problem for a fourth-order pseudoparabolic equation

The Cauchy problem for a fourth-order pseudoparabolic equation describing liquid filtration problems in fissured media, moisture transfer in soil, etc., is studied. Under certain summability and boundedness conditions imposed on the coefficients, the operator of this problem and its adjoint operator are proved to be homeomorphism between certain pairs of Banach spaces. Introduced under the same conditions, the concept of a θ-fundamental solution is introduced, which naturally generalizes the concept of the Riemann function to the equations with discontinuous coefficients; the new concept makes it possible to find an integral form of the solution to a nonhomogeneous problem.     

Nature of the cathode polarization during reduction of chromate ions in alkaline solutions

The effect of potential scanning rate and temperature on the kinetics of the reduction of chromate ions in alkaline solutions was studied, and the nature of polarization in separate stages of the cathode process was determined.