Analysis of the line broadening of diode-pumped solid-state lasers

The output parameters of the most effective system for pumping of solid-state lasers that is based on laser diode arrays are studied. The spatial profile of radiation of specific diode arrays and the differences in the radiation spectra of emitting elements are determined. It is demonstrated that the main reason for the generation of additional modes and the spectral broadening of laser radiation is related to thermal effects resulting from the spatial nonuniformity of radiation of the diode pumping system.     

Comparative characteristics of nutrition of the male population in some cities of the USSR (a cooperative study)]

The state of nutrition was studied in men of varying age groups (20-29, 30-39, 40-49, 50-54 years) living in different cities of the USSR. The standard method of food ration "daily reproduction" was used to investigate 25% of representative subsample in each age group. It has been found that the daily ration of men living in the European part of the USSR (Moscow, Kiev, Tallinn) is characterized by a rather high caloric value and by a significant imbalance in the consumption of the main food substances.     

Synthesis and characterization of Fe doped CeO2 nanoparticles for pigmented ultraviolet filter applications

Iron doped CeO2 nanoparticles with doping concentrations between 0 and 30 mol% were synthesized by the co-precipitation method for potential application as a pigmented ultraviolet filtration material. Each sample was calcined in air and in argon. The iron solubility limit in the CeO2 lattice was found to be between 10 and 20 mol%. Raman spectroscopy results revealed that both iron doping and argon calcination increase the concentration of oxygen vacancies in the CeO2 lattice. Iron doping causes a blue-shift of the absorbance spectrum, which can be linked to the decreased crystallite size, as obtained by XRD peak broadening using the Scherrer formula. The undoped samples showed weak ferromagnetic behaviour whereas the doped samples were all paramagnetic.     

Mechanism of the current flow in Pd-(heavily doped p-AlxGa1−x N) ohmic contact

The physical mechanism of the current flow in Pd-(heavily doped p-Al_xGa_1?x N) ohmic contact is studied. Chloride-hydride epitaxy was used to grow the p-Al_0.06Ga_0.94N solid solution with uncompensated acceptor concentration N _a –N _d ranging from 3×10¹⁸ up to 10¹⁹ cm^?3. Thermal vacuum deposition and subsequent thermal treatment were used to form an ohmic Pd contact. It is shown that, after the thermal treatment, the Pd-p-Al_0.06Ga_0.94N barrier contact with a potential barrier height of about 2.3 V becomes ohmic and the barrier height decreases to approximately 0.05 V. For uncompensated acceptor concentration N _a –N _d =3×10¹⁸ cm^?3, thermionic emission is found to be the main mechanism of the current through the Pd-p-Al_0.06Ga_0.94N ohmic contact. An increase in N _a –N _d to approximately 10¹⁹ cm^?3 in the solid solution leads to a transition from thermionic emission (at high temperatures) to tunneling (at low temperatures).     

EM Wave Propagation in Ferrite-Filled Transversely Magnetized Circular Waveguide

This paper presents a rigorous method of solving Maxwell's equations for ferrite-filled transversely magnetized circular waveguide. Solutions for cylindrical coordinate system are derived by using power series expansion of the field's potentials. Complex propagation constants are obtained by applying boundary conditions and representing fields in partial cylindrical modes. Plane wave representation of propagation is also considered. Numerical calculations of the propagation constants as well as the dominant waveguide mode reflection and transmission from a ferrite-filled waveguide section are presented.     

Structural and electrical properties of layered tetradymite-like compounds in the GeTe—Bi2Te3 and GeTe—Sb2Te3 systems

Analysis of the available crystallographic data shows that the GeTe-Bi₂Te₃ and GeTe-Sb₂Te₃ pseudobinary systems contain a wide variety of many-layered, long-period compounds belonging to the nGeTe · mBi₂Te₃ and nGeTe · mSb₂Te₃ homologous series. The Hall coefficient, thermoelectric power, and electrical conductivity of some of these compounds were measured over a wide temperature range. The temperature-dependent carrier mobility data suggest that both acoustic phonons and point defects contribute to the scattering of charge carriers. The lattice thermal conductivity of the many-layered, long-period compounds studied, κ_ph = 6–8 mW/(cm K), is notably lower than that of the constituent tellurides     

On the numerical properties of the schur approach for solving the matrix riccati equation

An a posteriori estimate of the relative error in the solution of the algebraic matrix Riccati equation, found by the Schur approach, is derived. It is shown that in some cases the Schur approach is numerically unstable.     

Deposition of Amorphous and Microcrystalline Films of Silicon by the Gas-Jet Plasma-Chemical Method

Semiconductors - Uniform thin films of amorphous and microcrystalline silicon are obtained within the forevacuum range of pressures by the gas-jet plasma-chemical method with the activation of gas...     

Tissue distribution of polybutylcyanoacrylate nanoparticles loaded with spin-labelled nitrosourea in Lewis lung carcinoma-bearing mice

The tissue distribution of polybutylcyanoacrylate nanoparticles (PBCN) with a diameter of 127 nm, loaded with 1-(2-chloroethyl)-3-(1-oxyl-2,2,6,6-tetramethylpiperidinyl)-1- nitrosourea (spin-labelled nitrosourea, SLCNU) is described. PBCN-suspensions were intraperitoneally (i.p.) injected into Lewis lung carcinoma bearing mice. The biodistribution of PBCN in the visceral organs, blood and tumor was studied by electron spin resonance (ESR) spectroscopy. A relatively low accumulation of nanoparticles in the liver and spleen was found. The accumulation was negligible in the i.m. implanted primary tumor. SLCNU-loaded nanoparticles were mainly found in the lungs, kidneys, and heart. The highest content of the particles studied was observed in the lungs of tumor bearing experimental animals damaged by metastases. These findings suggest that PBCN offer some opportunities in the targeting of SLCNU to lung metastases.