Hopping transport in the space-charge region of p-n structures with InGaN/GaN QWs as a source of excess 1/f noise and efficiency droop in LEDs

Semiconductors - It is shown that the emission efficiency and the 1/f noise level in light-emitting diodes with InGaN/GaN quantum wells correlate with how the differential resistance of a diode...     

Analysis of performance of fuel elements of the BOR-60 reactor with vibrocompacted uranium-plutonium oxide fuel

Translated from Atomnaya Énergiya, Vol. 66, No. 5, pp. 299–302, May 1989.     

Size and shape influence of luminescent orthovanadate nanoparticles on their accumulation in nuclear compartments of rat hepatocytes

In this paper the process of nonfunctionalized negatively charged orthovanadate nanoparticle accumulation and redistribution in cells dependent on their shape and size was investigated. Aqueous colloidal solutions of nReVO₄:Eu^3 + (Re = Gd, Y, La) luminescent nanocrystals of different sizes and shapes have been synthesized. The average sizes of spherical particles were 2, 20, and 300 nm, of spindle-like particles – 22 × 6.3 nm, and of rod-like particles – 57 × 4.4 nm. Luminescence of nReVO₄:Eu^3 + nanocrystals was effectively excited by UV and visible irradiation. By means of luminescence microscopy and luminescence microspectroscopy, it has been revealed that spherical nanocrystals with an average diameter of 2 nm tend to accumulate mainly in the rat hepatocyte nuclei in situ and also in the isolated nuclei of these cells. An additional experiment has shown that nanoparticles reveal tropism to nuclear structural components. The penetration into nuclei does not require any modifications of the surface of nanoparticle and is governed by the shape and size of nanoparticle and also is determined by the cellular type.     

Rolls with electric heating in equipment for the processing of plastics

Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 11, pp. 1–3, November, 1989.     

Characteristics of the martensite transformation in powder titanium nickelide

Conclusions Titanium nickelide powder produced by the calcium hydride reduction method possesses a very extended transformation range. Hence the material must exhibit the combined properties of superelasticity and shape memory over a very wide temperature range.During powder compacting additional factors (geometrical and physical) come into play which alter the transformation temperature. The effect of these becomes stronger with increasing compacting pressure. These factors are the binding of structural elements at contacts between particles, which may be released by the restoring stress which increases with increasing temperature, and also the participation of the usual plastic flow mechanisms in the process of deformation of the material.Translated from Poroshkovaya Metallurgiya, No. 11 (347), pp. 40–46, November, 1991.     

Effect of the built-in electric field on optical and electrical properties of AlGaAs/InGaAs/GaAs P-HEMT nanoheterostructures

This study is concerned with the photoluminescence spectra and electrical parameters of AlGaAs/InGaAs/GaAs pseudomorphic high-electron-mobility transistor (P-HEMT) structures with a quantum well grown at different depths L _b with respect to the surface. The samples are produced so as to make the concentration of electrons in the quantum well unchanged, as the barrier layer thickness L _b is reduced. It is established that the photoluminescence spectra of all of the samples exhibit peaks at the photon energies ħ _ω = 1.28−1.30 and 1.35–1.38 eV. The ratio between the intensities of these peaks increases as L _b is decreased. Calculations of the band structure show that variations in the spectra are due to the fact that the built-in electric field increases as the quantum well is set closer to the surface.