Theoretical Study of the Frequency Multiplier Based on Irregular Quarter-Wavelength Microstrip Resonator with Thin Magnetic Film

Russian Physics Journal - The characteristics of a frequency doubler on a resonant microstrip structure with a thin magnetic film were studied theoretically. The electrodynamic calculation of the...     

Effect of Ethanedioic Acid Additives on the Dissolution of Manganese Oxides in Sulfuric Acid Solution

The effect of ethanedioic acid additives on the rate of manganese(IV) oxide dissolution in sulfuric acid solutions was studied by kinetic and electrochemical methods. Interaction modes were established, and some details of the studied process mechanism were elucidated. Interaction schemes corresponding to the observed kinetic dependences were proposed.     

High-temperature heat capacity of Pb<Subscript>8</Subscript>La<Subscript>2</Subscript>(GeO<Subscript>4</Subscript>)<Subscript>4</Subscript>(VO<Subscript>4</Subscript>)<Subscript>2</Subscript> in the range 320–1000 K

The oxide compound Pb₈La₂(GeO₄)₄(VO₄)₂ with an apatite structure has been synthesized by a ceramic method. The effect of temperature on the molar hear capacity of polycrystalline samples in the temperature range 320–1000 K has been studied by differential scanning calorimetry. The results have been used to calculate the thermodynamic functions of the synthesized compound.     

Model of oxide film growth during anodization of aluminum

A theiretical model is proposed for describing the growth of an amorphous or polycrystalline oxide film on an aluminum surface during its anodization. an example of anodization in electrolytes based on salts of dicarboxylic acids is used to illustrate a satisfactory agreement of the model with the experimental data.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 30, No. 5, pp. 272–276, September–October, 1994.     

Ferromagnetic resonance features in anisotropic magnetic films with a metastable state of magnetic moment

In experiments on single-domain magnetic films with uniaxial in-plane anisotropy, a new homogeneous ferromagnetic resonance peak was observed in a planar magnetic field oriented at an angle to the easy magnetization axis and directed opposite to the magnetization projection onto the field direction. The peak was observed in fields smaller than the magnetization reversal field of the film, and the origin of the peak was found to be related to the metastable state of the magnetic moment. A good agreement was obtained between phenomenological calculations and experimental data.     

Singlet two-electron states in superconducting materials based on iron pnictides

Two-electron states with a zero pulse for the symmetry group of superconducting materials based on iron pnictides are considered. Cases are established for the introduction of one or two additional quantum numbers, notably, the internal quantum number, which characterizes single-electron states, or an additional quantum number, i.e. the irreducible representation index of the intermediate group. The octet structure of zeros observed in photoelectron spectra and the phase difference between the two-electron states on various Fermi surfaces are interpreted.     

Increasing Crystallization Rate in Growing Single Crystals of Quartz

A new method was proposed to increase the crystallization rate in growing single crystals of quartz. In this method, the crystallization is accelerated by using surfactants (polyethyleneamine, tetramethylammonium base, and polyethyleneimine) added to a soda-alkaline solution of standard concentration. Within studied ranges of pressures and concentrations of components of the solution, polyethyleneimine at a concentration of 0.002–0.05 wt % is the most efficient crystallization accelerator, which can increase the quartz crystal growth rate on the average by a factor of 2.     

Dislocation mobility in C<Subscript>60</Subscript> fullerite crystals

The dependences of the path of leading dislocations in indentation rosette rays on the load, the loading time, and the indentation temperature in the range 260 < T ≤ 373 K were studied for C₆₀ fullerite crystals. The dislocation mobility parameters are estimated: the exponent m characterizing the stress dependence of the dislocation velocity depends on the structural perfection of the crystal and ranges from 2.3 to 24.5, the activation energy for dislocation motion ΔH ₀ ? (0.4–0.5) eV, and the velocity of leading dislocations in indentation rosette rays v _l ? 10^?5?10^?4 cm/s. The data from micro-and macromechanical experiments are shown to agree with each other. The dislocation mobility is assumed to be controlled by the dislocation interaction with local barriers.     

Fullerit C<Subscript>60</Subscript> single crystals grown on earth and in space

Fullerit C₆₀ single crystals were grown by sublimation on Earth and under microgravity during the FOTON-M3 mission using the same growth parameters and the same multizoned electrovacuum POLIZON-M furnace. IR spectroscopy and X-ray measurements revealed the considerably better crystal structure of the crystals grown under microgravity.