Low field magnetocaloric effect and heat capacity of A-site ordered NdBaMn2O6 manganite

The magnetocaloric effect (MCE) in the A-site ordered manganite NdBaMn₂O₆ is studied. The MCE in this compound has an anomalous behavior. In low magnetic fields, the abrupt transitions between the direct and inverse magnetocaloric effects are observed. In a relatively strong magnetic field , the direct and inverse effects are observed only at cooling, while the heating mode reveals only an inverse MCE. The value of the MCE ( and for  kOe) does not reach high values, but the proximity of the effects occurring at room temperatures expects the use of both effects in the magnetic cooling technology.     

Approximation of analytical functions by k-positive linear operators in the closed domain

This work treats the problem of convergence for the sequences of linear \(k\) -positive operators on a space of functions that are analytic in a closed domain. By convergence in this space, we mean a uniform convergence in a closed domain that contains the original domain strictly inside itself, while the linear \(k\) -positive operators are naturally associated with Faber polynomials related to the considered domain. Until now, this problem has been solved in the space of functions analytic in an open bounded domain with the topology of compact convergence.     

Influence of oxygen pressure on the photochemical oxidation of phenol

The influence of the oxygen pressure on the photochemical oxidation of phenol is investigated. It is shown that raising the oxygen pressure from 0.1 to 0.7 MPa leads to an increase in the photochemical oxidation of phenol by a factor of approximately 3.7.     

Synthesis and antioxidant activity of 1-amino-4-phenyl-2-butanethiols

1-Amino-4-phenyl-2-butanethiols were synthesized and characterized and their antioxidant activity in auto-oxidation of cumene and in their reaction with cumyl peroxide radicals and cumyl hydroperoxide was studied.     

A study of the reaction of propane dehydrogenation on a Cr,Co,Ni,Bi,K/γ-Al2O3 catalyst in the presence of atmospheric oxygen

Russian Journal of Applied Chemistry - Effect of the C3H8 dehydrogenation temperature (560–650°C) and oxygen on the rates of C3H8 conversion and C3H6 formation was studied using a...     

Azabenzene chemisry. Part 2. Methylation of 2,3-dihydrooxazolo[4,5-b]pyridin-2-thione

Studies have been made on the reactions of 2,3-dihydrooxazolo[4,5-b]pyridin-2-thione and of its potassium and sodium salts with methylating agents under various conditions.See [1] for Part 1.Plant Substance Chemistry Institute, Uzbekistan Academy of Sciences, Tashkent 700170. Organic Nitrogen Technology Association, Interbioskrin, Moscow a/ya 218, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 87–89, January, 1999.     

Problems of modeling and optimal stabilization of the gas-lift process

The problems of motion of fluids, gases and gas–liquid mixtures in pipes related to gas-lift oil recovery are mathematically formulated as systems of nonlinear hyperbolic partial differential equations. Optimal-control problems are posed based on the proposed models and some real assumptions. These problems can be used to design programmed paths and controls, which underlie the controllers that stabilize the pressure or volume of injected gas. That the mathematical models agree with available field and laboratory data is demonstrated by examples     

Five-membered 2,3-dioxo heterocycles: LXIX. Direct heterocyclization of [3,4-dihydroisoquinolin-1(2H)-ylidene]-acetamides with 5-arylfuran-2,3-diones. Crystalline and molecular structure of (3E,5Z)-3-[3,3-dimethyl-3,4-dihydroisoquinolin-1(2H)-ylidene]-5-(2-oxo-2-phenylethylidene)pyrrolidine-2,4-dione

5-Arylfuran-2,3-diones react with (Z)-2-[3,3-dimethyl-3,4-dihydroisoquinolin-1(2H)-ylidene]acetamides to give (3E,5Z)-5-(2-aryl-2-oxoethylidene)-3-[3,3-dimethyl-3,4-dihydroisoquinolin-1(2H)-ylidene]-pyrrolidine-2,4-diones. The crystalline and molecular structures of one of the products were determined by X-ray analysis.     

Raman spectroscopic study of vibrational and orientational relaxation in melts of akaline-earth metal nitrates

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 52, No. 3, pp. 429–434, March, 1990.