Phase Relations in the Li–V2O5–Cu System at 600°C and Cathodic Properties of Cu x V2O5

The phase relations in the Li–V₂O₅–Cu system at 600°C are studied by x-ray diffraction. The existence of the known vanadium bronzes M _x V₂O₅ (M = Li, Cu) is confirmed, and the composition ranges of the related solid solutions are determined. -Li _x V₂O₅ (0.22 x 0.49) and -Li _x V₂O₅ (0.88 x 1.0) are shown to dissolve Cu, forming Li _x Cu _y V₂O₅ solid solutions with y = 0.72 – 1.48x and y = 0.58 – 0.18x, respectively. Cu _x Li _y V₂O₅ solid solutions (y= 0.51 – 0.76 x) are only obtained from -Cu _x V₂O₅ (0.24 x 0.67). -Li _x V₂O₅ and -Cu _x V₂O₅ form a continuous series of solid solutions. The cathodic properties of Li–V₂O₅–Cu materials in high-temperature pulsed lithium batteries are investigated.     

On the transport of intensity technique for phase retrieval

The Transport of Intensity technique is becoming a viable alternative to electron holography for phase retrieval in Transmission Electron Microscopy. However, several issues are still to be clarified in order to ascertain the applicability of the technique; among them, the controversy regarding its geometrical or wave-optical nature, as related to the phase detection limit. We show here that the Transport of Intensity is a wave-optical technique that works in a special regime of small defocus where the image intensity is linear with the defocus parameter. By a simple analytical example we show that the Transport of Intensity correctly reconstructs the electron optical phase shift even when the phase is smaller than pi, a value defining the boundary between the geometrical and wave approaches. Another example is given, the reconstruction of a phase jump, accompanied with experimental support showing that phase retrieval by Electron Holography and Transport of Intensity techniques yields results in good agreement.     

Electrochemical Oxidation of Am(III) Ions in HNO3 Solutions

Formal oxidation potentials (E0 ^p) of the Am(IV)/Am(III) couple were measured and the kinetics of electrochemical oxidation of Am(III) on platinum electrode in concentrated solutions of nitric acid (1-6 M) containing potassium phosphotungstate K_{1 0}P₂W_{1 7}O_{6 1} (KPW) was studied. The formal potential E0 ^p only slightly depends on the concentration of HNO₃ and is shifted toward the negative region by 1.0 V as compared with the standard values. The extent of Am(III) oxidation increases with increasing KPW concentration and decreasing concentration of nitric acid. Electrochemical oxidation of Am(III) is accompanied by radiochemical reduction of Am(IV) and is described by the equation -dC _{A m ( I I I )}/dt = (k + k ₁)C _Am(III) - k ₁ C ₀ - k ₀, where k is the apparent rate constant of electrochemical oxidation of Am(III), k ₁ is the apparent rate constant of Am(IV) reduction, and k ₀ is the constant of radiation-chemical reduction of Am(IV).     

Mathematical simulation of a supersonic flow around complex objects. Influence of the position of a wing on the gasdynamic characteristics of a complex object

Results of numerical simulation of a supersonic flow around spatial configurations of flying vehicles with the use of the Euler equations are presented. A model of a complex object was constructed on the basis of simpler base objects. Results of numerical solution of the problem on a three-dimensional flow around objects with an ogival-cylindrical airframe and a triangular wing with a diamond-shaped profile, arranged in different ways, at a Mach number M_∞ = 4.03 and an angle of attack α = 10.1^o have been analyzed. Calculation data were compared with the analogous data of a physical experiment. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 79, No. 3, pp. 47–55, May–June, 2006.     

Aero-optic effects in turbulent flows

Large-scale vortices and related aero-optic effects in a turbulent boundary layer, a free mixing layer, and an underwater stream have been mathematically simulated. The results are used for the analysis of distortions in the wavefront-phase function of a coherent light beam, which are induced by turbulent fluctuations in the parameters of the medium. The results of numerical calculations are compared to the experimental data and to a solution of the Reynolds equations.     

A Radiofrequency–Optical Modulation Spectroscope for Investigating Semiconductor Structures

A radiofrequency –optical spectroscope that makes it possible to investigate the modulation optical reflectance spectra of the various layers of a semiconductor structure is proposed and manufactured. Near the edge of the fundamental optical absorption, the light reflectance is modulated by an RF field with various spatial orientations. By using the RF–optical modulation spectroscope, new features of the electron–hole interaction in the layers of a selectively doped GaAs/AlGaAs heterostructure are discovered and investigated.