Simulation of Structural Transformations in Modified Near-Surface Layers of Crystals

2019 ◽  
Vol 970 ◽  
pp. 276-282
Author(s):  
Yury Borodin ◽  
Anastasia Mantina
Keyword(s):  
Quantum Wells ◽  
Riemannian Space ◽  
Structural Transformations ◽  
Thin Layers ◽  
Surface Layers ◽  
Near Surface ◽  
Internal Geometry ◽  
Structure Ordering

Superlattice formation in thin layers of oxidizing crystals and the effect of near-surface proton saturation on structure ordering, formation and periodical distribution of quantum wells have been discussed. The paper shows, it is necessary to develop non-Euclidean approach to the crystal’s internal geometry and consider, in consecutive order, the question of the four-dimentional Riemannian space into three-dimentional Eucliden space interpretation (RE interpretation).

scholarly journals Влияние индия на спектральные и структурные характеристики Lu-=SUB=-0.98-x-=/SUB=-In-=SUB=-x-=/SUB=-Eu-=SUB=-0.02-=/SUB=-BO-=SUB=-3-=/SUB=-

2020 ◽  
Vol 62 (12) ◽  
pp. 2110
Author(s):  
С.З. Шмурак ◽  
В.В. Кедров ◽  
А.П. Киселев ◽  
Т.Н. Фурсова ◽  
И.И. Зверькова
Keyword(s):  
Structural Modification ◽  
Sample Volume ◽  
Structural Transformations ◽  
Ion Concentration ◽  
Luminescence Spectra ◽  
Ir Absorption ◽  
Surface Layers ◽  
Near Surface ◽  
Structural Modifications ◽  
Absorption And Luminescence Spectra

The structure and the IR absorption and luminescence spectra of the Lu0.98-хInхEu0.02BO3 orthoborates are studied at 0 ≤ x ≤ 0.1. The Lu1-xInxBO3 solid solution, which consists of lutetium borate LuBO3 having two stable structural modifications (calcite, vaterite) and indium orthoborate InBO3 having one structural modification (calcite), crystallizes at x = 0.1 to form a calcite structure almost throughout the volume. We showed that the structural transformations in the Lu0.98-хInхEu0.02BO3 orthoborates induced by an increase in the In3+ ion concentration begin in the near-surface layers of the orthoborate microcrystals. The amount of calcite increases in the sample volume with x, and calcite occupies 98% of the Lu0.88In0.1Eu0.02BO3 sample volume.

The Use of Ratio-Recording Interferometry for the Measurement of Infrared Emission Spectra: Applications to Oxide Films on Copper Surfaces

1975 ◽  
Vol 29 (6) ◽  
pp. 496-500 ◽  
Author(s):  
D. Kember ◽  
N. Sheppard
Keyword(s):  
Emission Spectra ◽  
Black Body ◽  
Infrared Emission ◽  
Thin Layers ◽  
Oxide Surface ◽  
Surface Layers ◽  
Selective Reflection ◽  
Copper Surfaces ◽  
Emission And Absorption Spectra ◽  
Direct Correspondence

Infrared emission spectra from metal samples with oxide surface layers are shown to be very advantageously studied using the spectrum-ratioing facility of a recording infrared interferometer. The emission from a given sample is ratioed against that from a black-body emitter at the same temperature so as to give emittance as a function of wavenumber directly. This method has very useful application to irregularly shaped metal emitters. In the absence of selective reflection there is a direct correspondence between emission and absorption spectra for thin layers of an emitting substance. However, the presence of selective reflection leads to reduced emission and to considerable differences in the appearance of “absorption” and emission spectra in regions of strong absorption. Emission spectra obtained from copper plates heated, above 150°C, for different periods in air are shown clearly to indicate the presence of cuprous, Cu(I), and cupric, Cu(II), oxides in the surface layer.

scholarly journals Contribution of top barrier materials to high mobility in near-surface InAs quantum wells grown on GaSb(001)

2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Joon Sue Lee ◽  
Borzoyeh Shojaei ◽  
Mihir Pendharkar ◽  
Mayer Feldman ◽  
Kunal Mukherjee ◽  
...  
Keyword(s):  
Quantum Wells ◽  
High Mobility ◽  
Near Surface ◽  
Barrier Materials

Investigation of inhomogeneous structures of near-surface-layers in ion-implanted silicon

1998 ◽  
Vol 319 (1-2) ◽  
pp. 39-43 ◽  
Author(s):  
Z Swiatek ◽  
J.T Bonarski ◽  
R Ciach ◽  
Z.T Kuznicki ◽  
I.M Fodchuk ◽  
...  
Keyword(s):  
Surface Layers ◽  
Near Surface ◽  
Ion Implanted

45° REFLECTOMETRY OF SEMICONDUCTOR QUANTUM WELLS

2001 ◽  
Vol 15 (17n19) ◽  
pp. 683-687
Author(s):  
A. SILVA-CASTILLO ◽  
F. PEREZ-RODRIGUEZ
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Growth Direction ◽  
Angle Of Incidence ◽  
Near Surface ◽  
New Information ◽  
Difference Formula ◽  
Exciton Polaritons ◽  
The Difference ◽  
First Time

We have applied the 45° reflectometry for the first time to study exciton-polaritons in quantum wells. The 45° reflectometry is a new polarization-modulation technique, which is based on the measurement of the difference [Formula: see text] between the p-polarization reflectivity (Rp) and the squared s-polarization reflectivity [Formula: see text] at an angle of incidence of 45°. We show that [Formula: see text] spectra may provide qualitatively new information on the exciton-polariton modes in a quantum well. These optical spectra turn out to be very sensitive to the zeros of the dielectric function along the quantum-well growth direction and, therefore, allow to identify the resonances associated with the Z exciton-polariton mode. We demonstrate that 45° reflectometry could be a powerful tool for studying Z exciton-polariton modes in near-surface quantum wells, which are difficult to observe in simple spectra of reflectivity Rp

Important factors in the tracking of tropical cyclones in operational models

2021 ◽  
Author(s):  
Timothy Marchok
Keyword(s):  
Geophysical Fluid Dynamics Laboratory ◽  
Surface Layers ◽  
Individual Parameter ◽  
Near Surface ◽  
Parameter Configuration ◽  
Multiple Variables ◽  
The Mean ◽  
Tropical Cyclone Center ◽  
Multiple Configurations ◽  
Better Than

AbstractMultiple configurations of the Geophysical Fluid Dynamics Laboratory vortex tracker are tested to determine a setup that produces the best representation of a model forecast tropical cyclone center fix for the purpose of providing track guidance with the highest degree of accuracy and availability. Details of the tracking algorithms are provided, including descriptions of both the Barnes analysis used for center-fixing most variables and a separate scheme used for center-fixing wind circulation. The tracker is tested by running multiple configurations on all storms from the 2015-2017 hurricane seasons in the Atlantic and eastern Pacific Basins using forecasts from two operational National Weather Service models, the Global Forecast System (GFS) and the Hurricane Weather Research and Forecast (HWRF) model. A configuration that tracks only 850 mb geopotential height has the smallest forecast track errors of any configuration based on an individual parameter. However, a configuration composed of the mean of eleven parameters outperforms any of the configurations that are based on individual parameters. Configurations composed of subsets of the eleven parameters and including both mass and momentum variables provide results comparable to or better than the full 11-parameter configuration. In particular, a subset configuration with thickness variables excluded generally outperforms the 11-parameter mean, while one composed of variables from only the 850 mb and near-surface layers performs nearly as well as the 11-parameter mean. Tracker configurations composed of multiple variables are more reliable in providing guidance through the end of a forecast period than are tracker configurations based on individual parameters.

The Effect of As+ Ion Implantation and Annealing on the Electrical Properties of Near-Surface Layers in Graded-Gap n-Hg0.78Cd0.22Te Films

2021 ◽  
Vol 47 (2) ◽  
pp. 189-192
Author(s):  
A. V. Voitsekhovskii ◽  
S. N. Nesmelov ◽  
S. M. Dzyadukh ◽  
V. S. Varavin ◽  
S. A. Dvoretskii ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Ion Implantation ◽  
Surface Layers ◽  
Near Surface

scholarly journals Movement of the Ward Hunt Ice Shelf, Ellesmere Island, N.W.T., Canada

1971 ◽  
Vol 10 (59) ◽  
pp. 211-225 ◽  
Author(s):  
E. Dorrer
Keyword(s):  
Power Flow ◽  
Field Work ◽  
Ellesmere Island ◽  
Ice Shelf ◽  
Surface Layers ◽  
Atmospheric Refraction ◽  
Near Surface ◽  
Angle Measurements ◽  
Ice Velocity ◽  
Ice Forces

AbstractThe movement at a marginal location on the Ward Hunt Ice Shelf, northern Ellesmere Island, was determined by repeated survey measurements with theodolite and geodimeter. The purpose and duration of the field work, and reduction of the observational data are described, and the resulting mean ice velocity of 0.53 m year-1is discussed. Strain-rates of a 1 km by 1 km deformation figure are determined. The parametersnandBof Glen’s power flow law are determined by using the equations given by Nye and Weertman. The results are compared with experimental data. Computed ice stresses show that the “ridge-and-trough" structure on the ice shelf surface is not originated by internal ice forces. The elevations of all survey markers have been determined from vertical-angle measurements, and the peculiarities of atmospheric refraction in near-surface layers are discussed.

scholarly journals Tropospheric BrO column densities in the Arctic derived from satellite: retrieval and comparison to ground-based measurements

2012 ◽  
Vol 5 (11) ◽  
pp. 2779-2807 ◽  
Author(s):  
H. Sihler ◽  
U. Platt ◽  
S. Beirle ◽  
T. Marbach ◽  
S. Kühl ◽  
...  
Keyword(s):  
Boundary Layer ◽  
The Arctic ◽  
Trace Gas ◽  
Natural Phenomenon ◽  
Satellite Measurements ◽  
Surface Layers ◽  
Vertical Column ◽  
Near Surface ◽  
The Vertical Distribution ◽  
Good Agreement

Abstract. During polar spring, halogen radicals like bromine monoxide (BrO) play an important role in the chemistry of tropospheric ozone destruction. Satellite measurements of the BrO distribution have become a particularly useful tool to investigate this probably natural phenomenon, but the separation of stratospheric and tropospheric partial columns of BrO is challenging. In this study, an algorithm was developed to retrieve tropospheric vertical column densities of BrO from data of high-resolution spectroscopic satellite instruments such as the second Global Ozone Monitoring Experiment (GOME-2). Unlike recently published approaches, the presented algorithm is capable of separating the fraction of BrO in the activated troposphere from the total BrO column solely based on remotely measured properties. The presented algorithm furthermore allows to estimate a realistic measurement error of the tropospheric BrO column. The sensitivity of each satellite pixel to BrO in the boundary layer is quantified using the measured UV radiance and the column density of the oxygen collision complex O4. A comparison of the sensitivities with CALIPSO LIDAR observations demonstrates that clouds shielding near-surface trace-gas columns can be reliably detected even over ice and snow. Retrieved tropospheric BrO columns are then compared to ground-based BrO measurements from two Arctic field campaigns in the Amundsen Gulf and at Barrow in 2008 and 2009, respectively. Our algorithm was found to be capable of retrieving enhanced near-surface BrO during both campaigns in good agreement with ground-based data. Some differences between ground-based and satellite measurements observed at Barrow can be explained by both elevated and shallow surface layers of BrO. The observations strongly suggest that surface release processes are the dominating source of BrO and that boundary layer meteorology influences the vertical distribution.

Sign in / Sign up

Export Citation Format

Share Document