Model of the penetration of a metal barrier by a rod projectile with an angle of attack

A relatively simple dynamic model is proposed for calculating parameters characterizing the penetration of a barrier by a rod projectile with an angle of attack. Together with the factors examined in the case of axisymmetric penetration within the framework of the well-known Alekseevskii-Tate scheme, the model considers the action of transverse forces and rotation of the rod. Calculations of the penetration of steel barriers by tungsten projectiles with a relative length of 12.8–17.4 at collision velocities of 1800–2100 m/sec along a normal to the surface showed good agreement with experimental data for angles of attack from 0 to 68°.All-Union Scientific Research Institute of Experimental Physics, 607200 Aramas-16. Translated from Fizika Goreniya i Vzryva, Vol. 31, No. 3, pp. 104–109, May–June, 1995.     

Possibilities for Producing Radionuclides in Nuclear Power Plants with RBMK Reactors

It is shown that radiation doping of silicon and the production of medical and industrial radioisotopes in the reactors at the Leningrad nuclear power plant are possible and safe. The production of cobalt with specific activity ~100 Ci/g in an RBMK-1000 reactor is studied. Some promising developments for improving the quality of the radioisotopes produced are described. It is shown that the production volumes can be increased by linking up other nuclear power plants with RBMK reactors into the production chain.     

High performance quantum dot lasers on GaAs substrates operating in 1.5 /spl mu/m range

Stacked InAs/InGaAs quantum dots are used as an active media of metamorphic InGaAs-InGaAlAs lasers grown on GaAs substrates by molecular beam epitaxy. High quantum efficiency (/spl eta//sub i/>60%) and low internal losses (/spl alpha/<3-4 cm/sup -1/) are realised. The transparency current density per single QD layer is estimated as /spl sim/70 A/cm/sup 2/ and the characteristic temperature is 60 K (20-85/spl deg/C). The emission wavelength exceeds 1.51 /spl mu/m at temperatures above 60/spl deg/C.     

Temperature characteristics of low-threshold high-efficiency quantum-dot lasers with the emission wavelength from 1.25 to 1.29 µm

The temperature behavior of the operation characteristics of low-threshold (the threshold current density is below 100 A/cm²) high-efficiency (differential quantum efficiency is as high as 88%) injection laser heterostructures is studied. The active region of structures emitting in the range from 1.25 to 1.29 μm included two, five, and ten layers of InAs-GaAs quantum dots. It is shown that both the threshold current density and the external differential quantum efficiency become N-shaped functions of temperature as the distribution of carriers in the active region changes from nonequilibrium to equilibrium one. __________ Translated from Fizika i Tekhnika Poluprovodnikov, Vol. 37, No. 10, 2003, pp. 1270–1273. Original Russian Text Copyright ? 2003 by Novikov, Maksimov, Shernyakov, Gordeev, Kovsh, Zhukov, Mikhrin, Maleev, Vasil’ev, Ustinov, Alferov, Ledentsov, Bimberg.     

Amplification of femtosecond pulses over by 18 dB in a quantum-dot semiconductor optical amplifier

We demonstrate amplification (> 18 dB) of 200-fs pulses in a quantum-dot (QD) semiconductor amplifier. Our measurements have shown that such QD devices can provide amplification of femtosecond pulses over a spectral range that exceeds 100 nm.     

Computer panoramic tomography for industrial application

Problems of the development and application of a high-capacity X-ray tomograph intended for testing bar-type fuel elements are considered. The tomograph created by the authors and designed for detecting and measuring flaws in welded joints in an automatic mode is briefly described, and its performance characteristics are presented. A technique for measuring flaws using reconstructed panoramic images, which is optimal for rejecting defective fuel elements under the conditions of a technological conveyor, is presented. The results of experimental tests of the tomograph involving automatic measurements of pore-type flaws in different detection modes are presented. The results of this study can be useful for other industrial applications of X-ray tomography.