Metal diffraction gratings as laser power or energy dividers

The authors survey published results on the application of metal diffraction gratings as laser power or energy dividers when the laser beam is split into two approximately equal pans. The normal incidence of laser radiation on metal diffraction gratings of various profiles in the case of three propagating diffraction orders n=0, ±1 is discussed, along with the case of oblique incidence with only two propagating diffraction orders n=0 and n =–1.Translated from Izmeritel'naya Tekhnika, No. 2, pp. 22–26, February, 1994.     

Alpha induced reactions on Sn: An experimental study of excitation functions and possible production pathways

In the frame of a systematic study of light ion induced threshold reactions on natural tin (Sn) excitation functions for alpha particles induced reactions are presented in a 12–38 MeV energy domain. Using a stacked foil activation method the following radioisotopes were identified: ¹¹⁶Te, ¹¹⁷Te, ¹¹⁸Te, ¹¹⁹Te, ¹²¹Te, ¹²³Te, ¹¹⁷Sb, ¹¹⁸Sb, ¹²⁰Sb, ¹²²Sb, ¹²⁴Sb, ¹²⁶Sb, ¹¹⁷Sn, ¹¹¹In. The experimental cross sections for these isotopes are presented for the first time in this energy range and a direct comparison with values calculated with the ALICE-IPPE code is discussed. Possible use of these data for production of some isotopes relevant in nuclear medicine is suggested.     

High-resolution X-ray photoelectron spectroscopy and characteristic electron-energy loss spectroscopy of the electronic structure of phosphorus-implanted silicon and quantum dots of silicon dioxide with silicon impurities

The effect of phosphorus impurities on the electronic structure of silicon single crystals and SiO₂: Si nanocomposites is studied. The SiO₂: Si structures with phosphorus impurities that are annealed over 2 h at a temperature of 1000°C exhibit an increase in the photoluminescence peak related to Si nanocrystals. The experimentally determined densities of states in the valence and conduction bands of SiO₂: Si composites are in good agreement with the local electronic structure in the vicinity of silicon impurities that is calculated within the approximation of linear muffin-tin orbitals.     

A mechanism of formation of gas-liquid systems

A mathematical model is constructed for the process of formation of a disperse liquid-gas bubble system as a result of evolution of dissolved gas due to changes in the external pressure. The model is implemented numerically for chlorine and air and is used to explain the difference in the rates of bubble growth at small and large excess pressures.     

Influence of a Jump in the Power of Laser Radiation on Its Measurement

Simulation and investigation of the effect of an isolated jump on realization of the unit of power of laser radiation and dissemination of the size of the unit are considered. Results are obtained by means of a newly developed algorithm that characterizes the behavior of the mean value of a signal and the standard deviation of a system as functions of the parameters of a jump in the power of laser radiation and the length and amplitude of the jump. If information concerning the time when a jump occurs is available, the proposed algorithm makes it possible to take into account how a jump affects the ultimate result of a measurement.     

Collagen and its rational content in meat products: Part 1. Analytical studies

Computer-assisted simulation has been used to study the effect of collagen content on the biological value of meat proteins. It has been shown that an increase in the collagen content from 2·5% to 15-20% of the total amount of proteins contained in minced meat tangibly enhances protein utilization for tissue synthesis. Hence, the above collagen content in meat products heightens their nutritional and biological value and renders them more suited for human metabolism.     

Metallochemical Analysis of the Reaction in a Mixture of Nickel and Aluminum Powders

Phaseformation processes are considered at the level of a mesocell of a mixture with the use of the state diagram for a binary system. Consecutive schemes of metallochemical reactions of formation and decomposition of intermetallide compounds in a mixture of nickel and aluminum powders are suggested. The problem of diffusion annealing of this mixture is numerically solved for two different conditions: at a constant temperature and at a temperature slowly increasing by a linear law.