The photospectral system for the space experiment «Uragan»

Belyaev, B. I.; Belyaev, Yu. V.; Domaratskii, A.V.; Katkovskyi, L.V.; Krot, Yu.A.; Rogovets, A. V.; Khvalei, S.V.

doi:10.15407/knit2010.02.041

Cited by 3 publications

(2 citation statements)

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“…where

ε_{II}^{T}

is the in-plane strain at the growth temperature;

ε_{II}^{T}

is the in-plane strain at RT;

a_{S}^{RT}

and

a_{L}^{RT}

are lattice constants of the substrate and the layers at RT;

α_{II}^{S}

and

α_{II}^{L}

are thermal expansion coefficients of the substrate and the layers (

α_{II}^{GaN}

= 6.2 × 10 −6 /K,

α_{II}^{AlN}

= 7 × 10 −6 /K,

α_{II}^{A l 2 O 3}

= 7.5 × 10 −6 /K) [20,21]; and

normalΔ T

is the difference between T gr. and RT.…”

Section: Resultsmentioning

confidence: 99%

Substrate effects on the strain relaxation in GaN/AlN short-period superlattices

et al. 2012

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We present a comparative study of the strain relaxation of GaN/AlN short-period superlattices (SLs) grown on two different III-nitride substrates introducing different amounts of compensating strain into the films. We grow by plasma-assisted molecular beam epitaxy (0001)-oriented SLs on a GaN buffer deposited on GaN(thick)-on-sapphire template and on AlN(thin)-on-sapphire template. The ex-situ analysis of strain, crack formation, dislocation density, and microstructure of the SL layers has established that the mechanism of strain relaxation in these structures depends on the residual strain in substrate and is determined mainly by the lattice mismatch between layers. For growth on the AlN film, the compensating strain introduced by this film on the layer prevented cracking; however, the densities of surface pits and dislocations were increased as compared with growth on the GaN template. Three-dimensional growth of the GaN cap layer in samples with pseudomorphly grown SLs on the AlN template is observed. At the same time, two-dimensional step-flow growth of the cap layer was observed for structures with non-pseudomorphly grown SLs on the GaN template with a significant density of large cracks appearing on the surface. The growth mode of the GaN cap layer is predefined by relaxation degree of top SL layers.

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“…where

ε_{II}^{T}

is the in-plane strain at the growth temperature;

ε_{II}^{T}

is the in-plane strain at RT;

a_{S}^{RT}

and

a_{L}^{RT}

are lattice constants of the substrate and the layers at RT;

α_{II}^{S}

and

α_{II}^{L}

are thermal expansion coefficients of the substrate and the layers (

α_{II}^{GaN}

= 6.2 × 10 −6 /K,

α_{II}^{AlN}

= 7 × 10 −6 /K,

α_{II}^{A l 2 O 3}

= 7.5 × 10 −6 /K) [20,21]; and

normalΔ T

is the difference between T gr. and RT.…”

Section: Resultsmentioning

confidence: 99%

Substrate effects on the strain relaxation in GaN/AlN short-period superlattices

et al. 2012

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“…Обратная линейная дисперсия полихроматора с вогнутой ДР определяет энергетику спектрометра и спектральное разрешение. Этот параметр можно вычислить по приближенной формуле (10): где n -плотность штрихов решетки; m -порядок дифракции; r b -расстояние от решетки до приемника; β 1 , β 2 -углы дифракции для длин волн начала и конца рабочего спектрального диапазона [10].…”

Section: конструкция модульного гиперспектрометраunclassified

The Small-Scale Satellite Modular Hyperspectrometer

Martinov

Беляев

Beliaev

et al. 2019

Prib. metody izmer.

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Recently in the world practice of aerospace monitoring of the Earth there has been an increasingly active using of methods and devices of hyperspectral imaging. Thus creation of systems designed for recording hyperspectral data and methods for their processing is an actual task for remote sensing of the Earth. The aim of the article was to develop and create a small-sized satellite modular hyperspectrometer in visible and near infrared range, designed to receive information on remote sensing of the Earth in order to constantly update data about state of natural environment and infrastructure objects using videospectral methods with the possibility of comprehensive study of both spectral and spatial characteristics of the observed objects.A small-scale satellite modular hyperspectrometer has been developed. The distinctive features of the equipment include high spectral resolution and small dimensions. A hyperspectrometer includes two main modules: an optical module and an electronics one. The design feature of the optical module is the use of a concave holographic diffraction grating in a polychromator. The electronics module is based on a single board computer. Their description and design features, a scheme for the formation of a hypercube and software for its further processing are presented in the paper. The developed hardware (test equipment, a space experiment simulator and a spatial scanning system) for efficiency testing is presented also, as well as test measurements ware conducted. It is worth noting the extremely small dimensions for this class of devices in comparison with analogues as well as the vibration resistance of the equipment.

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