A method of determining the electron reflection coefficient from the emitter surface in a thermionic-emission converter

A method is proposed for determining the transparency of the potential barrier at the surface of the emitter in a thermionic-emission converter by means of measured arc voltage-current characteristics. That method can also be used to determine the barrier transparency for the collector by measuring the voltage-current characteristics when the current flows from the collector to the emitter. The method can be used to track the variation in the reflection coefficient from the plasma for the emission electrons. Kurchatov Institute Russian Scientific Center. Translated from Atomnaya énergiya, Vol. 86, No. 2, pp. 107–113, February, 1999.     

Superplastic behavior of a 7055 aluminum alloy

It is shown that a high strength 7055 aluminum alloy with partially recrystallized initial structure exhibits superplastic behavior in the temperature interval 400–490 °C within a wide strain rate range from 8.3×10⁻⁵ to 3.3×10⁻² s⁻¹. Maximum total elongation of about 960% and strain rate sensitivity coefficient, m, of 0.6 were obtained at a temperature of 450 °C and a strain rate of 3.3×10⁻⁴ s⁻¹.     

Metal-Semiconductor Nanoheterostructures with an AlGaN Quantum Well and In Situ Formed Surface Al Nanoislands

We report on fabrication and studies of composite heterostuctures consisting of an Al_0.55Ga_0.45N/A_l0.8Ga_0.2N quantum well and surface Al nanoislands, grown by plasma-assisted molecularbeam epitaxy on c-sapphire substrates. The influence of a substrate temperature varied between 320 and 700ºC on the size and density of the deposited Al nanoislands is evaluated. The effect of Al nanoislands on decay kinetics of the quantum well middle-ultraviolet photoluminescence has been investigated by time resolved photoluminescence. The samples with the maximum density of Al nanoislands of 10⁸ cm^–2 and lateral dimensions in the range of 100–500 nm demonstrated shortening of the photoluminescence lifetime, induced by interaction of the emitting quantum well and the plasmonic metal particles.