Modification of the defect structure in binary semiconductors under the action of microwave radiation

Possible athermic processes caused by microwave processing (at f = 2.45 and 84 GHz) of semiconductors that influence their structure are analyzed. Models explaining the variation of the concentration of point and extended defects upon microwave irradiation are proposed. These models are qualitatively corroborated by experimental data for the structure and luminescence of semiconductors.     

Electrochemical Determination of Dopamine with Ruthenium(III)-Modified Glassy Carbon and Screen-Printed Electrodes

Here is reported for the first time the application of sodium bis[N-2-oxyphenyl-5-bromosalicylideneiminato-ONO]ruthenate(III) as a mediator with multiwalled carbon nanotubes and Nafion at glassy carbon and screen-printed electrodes for the determination of dopamine in the presence of ascorbic acid. Electrochemical studies were performed using cyclic voltammetry, differential pulse voltammetry, and flow injection amperometry. In flow injection mode, the flow rate was 0.4?mL?min^?1, the injection volume 250?µL, and the operation potential 0.05?V vs. Ag/AgCl. In 0.1M pH 7.5 phosphate buffer, the sensor provided a linear dynamic range up to 50?mg?L^?1 dopamine with a detection limit of 0.11?±?0.04?mg?L^?1. The sensor was used for the determination of dopamine in ampoules of dopamine hydrochloride by cyclic voltammetry, differential pulse voltammetry, and flow injection amperometry.     

Proof of lower estimates for the complexity of self-correcting circuits by the method of basis changing

A method for obtaining new lower estimates for the implementation complexity of individual Boolean functions is presented in the paper. The method is based on the transition from some considered basis to another one possessing already known good lower estimates for the complexity of those functions. The effective use of this method is illustrated by the example of obtaining the asymptotic value for the implementation complexity of threshold functions by self-correcting circuits composed of multiple-input elements.     

亚临界与超临界压力水在管内的对流传热与传质

本文对含有金属腐蚀物杂质的亚临界与超临界压力水在竖直加热圆管内的受迫对流与混合对流传热与传质进行了数值模拟，分析了变物性、浮升力以及压力等因素对管内对流传热与传质的影响。结果表明：浮升力使自下而上流过竖直加热圆管的对流传热和传质增强；在不同的温度条件下，超临界压力水的热物性对传热传质的影响有很大不同。     

The preparation of hydrogen by the catalytic pyrolysis of ethanol on a nickel catalyst

High efficiency of a nickel catalyst on the SiO₂ support in low-temperature ethanol conversion as a method for the preparation of hydrogen was demonstrated. One mole of the alcohol was found to yield one mole of hydrogen. The catalyst studied did not stimulate the methanation and shift reactions.     

A method for determining the equilibrium states of dynamic systems

A heuristic method is presented for determining the equilibrium states of motion of dynamic systems, in particular, spacecraft. The method can also be applied to the solution of sets of linear or nonlinear algebraic equations. A positive-semidefinite functional is formed to convert the problem to that of finding those minimum points where the functional vanishes. The process is initiated within a selecteddomain of interest by random search; convergence to a minimum is obtained by a modified Davidon's deflected gradient technique. To render this approach feasible in the presence of constraints, the functional is modified to include penalty terms which cause the functional to approach infinity at the constraint boundaries. Close approximations to solutions near the constraint boundaries are found by applying Carroll's approach in successively reducing the weighting factors of the penalty terms. After finding a minimum, the local domain around this point is eliminated by adding to the functional an interior constraint term, representing the surface under a hypersphere centered at the minimum point. The domain of consideration now becomes the subdomain formed by subtracting the space contained within this hypersphere from the previous domain of interest. Minima are now sought within the remaining space, as before.This paper is derived from research performed by the author while employed by TRW Systems Group, Redondo Beach, California.The author acknowledges the helpful suggestions of Dr. G. Bekey, University of Southern California, and those of Mr. E. A. Quast, Dr. M. P. Scher, and Dr. R. J. Wiley, Dynamics Department, TRW Systems Group, Redondo Beach, California.     

Magnetoelectric effect in samarium molybdate

This paper reports on the nonlinear magnetoelectric effect (MEE) in the orthorhombic ferroelectric ferroelastic β′ phase of samarium molybdate Sm₂(MoO₄)₃ observed in magnetic fields up to 20 T and temperatures from 4.4 to 0.43 K. The magnetic-field-induced electric polarization in Sm₂(MoO₄)₃ is an order of magnitude larger than that in isomorphic Gd₂(MoO₄)₃. This provides support for the magnetostriction mechanism proposed by us for the MEE in rare-earth molybdates. The polarization in Sm₂(MoO₄)₃ was found to fall off with time. The relaxation time constant τ increases with decreasing temperature from τ=10² s at T=4.4 K to τ≈10³ s at T=0.43 K.     

The Effect of Sc<Subscript>2</Subscript>O<Subscript>3</Subscript> on the Physicochemical Properties of Low-Melting Cryolite Melts КF–AlF<Subscript>3</Subscript> and КF–NaF–AlF<Subscript>3</Subscript>

Quasibinary phase diagrams of the system “low-melting cryolite–Sc₂O₃” the potential media for synthesizing alloyed alloys Al–Sc are plotted by the method of thermal analysis. The phase diagrams of (KF–NaF–AlF₃)–Sc₂O₃ with different content of NaF and the cryolite ratio (CR) 1.3 and 1.5 are the diagrams with simple eutectics. The liquidus temperature of the (KF–AlF₃)–Sc₂O₃ system increases with the increase in the Sc₂O₃ concentration due to the formation of a high-melting compound: potassium hexafluoroscandiate К₃ScF₆. The solubility of Sc₂O₃ in low-melting cryolite melts KF–NaF–AlF₃ increases with the increase in temperature and CR. In contrast Al₂O₃, the solubility of Sc₂O₃ in melts containing KF–AlF₃ with CR = 1.3–1.5 is much lower than in cryolite melts containing NaF. The conductivity of low-melting cryolite melts measured by the method of impedance spectroscopy decreases in proportion to the Sc₂O₃ concentration in the similar way as in salt melts containing Al₂O₃. Based on the experimental data obtained, the compositions of low-melting cryolite melts are proposed for the synthesis of doped Al–Sc alloys.     

Synthesis of acyl derivatives of L-tryptophan containing residues of anthranilic and oxalic acids

Oxamoyl derivatives of dipeptide, N-anthranoyl-L-tryptophan, were synthesized by acylation of L-tryptophan methyl ester hydrochloride with 3,1-benzoxazinone derivatives. A one-stage procedure was developed for the synthesis of esters of N-[2-(N′-R-amidooxalyl)aminobenzoyl]-L-tryptophan.     

Growth of Faceted Pores in a Crystal by the Burton–Cabrera–Frank Mechanism

Physics of the Solid State - The growth of a faceted pore in a crystal by the Burton–Cabrera–Frank mechanism under action of a mechanical tensile load is considered. The growth is...