scholarly journals The effect chemical treatment of the substrate cadmium telluride on the quality of epitaxial structures

2019 ◽  
Vol 21 (1) ◽  
pp. 43-47
Author(s):  
V. V. Paramonov ◽  
O. V. Novikova ◽  
V. G. Kosushkin
Keyword(s):  
Mass Transfer ◽  
Sulfuric Acid ◽  
Cadmium Telluride ◽  
Hydrobromic Acid ◽  
Potassium Dichromate ◽  
Epitaxial Layers ◽  
Building Structures ◽  
Isobutyl Alcohol ◽  
Nonaqueous Solutions

The etching of wafers of cadmium telluride in aqueous and nonaqueous solutions before the epitaxial process of building structures CdxHg1-xTe and its influence on the surface quality of epitaxial layers. As the etchants investigated 2—20 % solution of bromine in isobutyl alcohol, 5 % solution of bromine in methanol, dimethylsulfoxide, ethylene glycol, solutions of bromine in hydrobromic acid and mixed with glycerin, a saturated solution of potassium dichromate in sulfuric acid. The speed of etching was varied from 0.2 to 9 µm/min. Polishing Set nature of the etching substrate of cadmium telluride in 5 % solution of bromine in i-butanol, the dissolution process is diffusion in nature and is limited by the mass transfer of the reactants in the temperature range of 10—60 °C, depending on the concentration of bromine and the viscosity of the solution. Studied the morphology and surface finish of epitaxial layers of CdxHg1-xTe, depending on the method of etching the original substrate. Found the optimal compositions of etchants for precipitaciones processing of obtaining structures with a height of asperities of the surface at 0.1 atm.

Preparation of Thin Cadmium Telluride Samples for Electron Microscope Studies

1974 ◽  
Vol 32 ◽  
pp. 548-549
Author(s):  
T. J. Magee ◽  
J. Peng ◽  
J. Bean
Keyword(s):  
Electron Microscope ◽  
Sulfuric Acid ◽  
Solid State ◽  
Sample Preparation ◽  
Cadmium Telluride ◽  
Potassium Dichromate ◽  
Optical Components ◽  
The Past ◽  
Solid State Devices

Cadmium telluride has become increasingly important in a number of technological applications, particularly in the area of laser-optical components and solid state devices, Microstructural characterizations of the material have in the past been somewhat limited because of the lack of suitable sample preparation and thinning techniques. Utilizing a modified jet thinning apparatus and a potassium dichromate-sulfuric acid thinning solution, a procedure has now been developed for obtaining thin contamination-free samples for TEM examination.

scholarly journals Assess the Effectiveness of protective Concrete coatings of microbiological sulfuric acid Aggression

2019 ◽  
Vol 97 ◽  
pp. 02022
Author(s):  
Viktor Sopov ◽  
Julia Danchenko ◽  
Ekaterina Latorez
Keyword(s):  
Sulfuric Acid ◽  
Building Structures ◽  
Predominant Role ◽  
Microbiological Processes ◽  
Repair Materials ◽  
Bactericidal Properties ◽  
Mineral Acids ◽  
Concrete Building ◽  
Modified Epoxy

Specification of corrosion processes in sewerage networks, the predominant role of microbiological processes in them requires the protection of concrete with materials resistant to specific biogenic sulfuric acid aggression. The effective protective materials, in this case, are those that, in addition to acid-proofing materials, have bactericidal properties. Polymer composite materials (PCM) of cold curing based on modified epoxy-resin, resins with dispersed oxides as fillers are widely used in construction. Unique properties and simple technologies make it possible to use them as injection formulations for repair, restoration and restoration of building structures and structures, waterproofing and facing materials, for impregnating, gluing and coating metal, wooden, brick and concrete building structures and parts. In the reconstruction and restoration of sewerage collectors operating under conditions of exposure to liquid biochemically aggressive media with mineral acids and organic substances, particular attention is paid to the permeability of repair materials. Based on the results of the study, PCM compositions were chosen whose estimated lifetime is about 20 years, ensuring reliable protection of the sewage collectors from corrosion.

A Tem study of GaN Grown by ELO on (0001) 6H-SiC

1999 ◽  
Vol 595 ◽  
Author(s):  
P. Ruterana ◽  
B. Beaumont ◽  
P. Gibart ◽  
Y. Melnik
Keyword(s):  
Basal Plane ◽  
Lattice Mismatch ◽  
Early Stage ◽  
Vapour Phase ◽  
Epitaxial Layers ◽  
Prismatic Plane ◽  
Vapour Phase Epitaxy ◽  
Hexagonal Shape ◽  
To Come

AbstractThe misfit between GaN and 6H-SiC is 3.5% instead of 16% with sapphire, the epitaxial layers have similar densities of defects on both substrates. Moreover, the lattice mismatch between AlN and 6H-SiC is only 1%. Therefore, epitaxial layer overgrowth (ELO) of GaN on AlN/6H-SiC could be a route to further improve the quality of epitaxial layers. AlN has been grown by Halide Vapour Phase Epitaxy (HVPE) on (0001) 6H-SiC, thereafter a dielectric SiO2 mask was deposited and circular openings were made by standard photolithography and reactive ion etching. We have examined GaN layers at an early stage of coalescence in order to identify which dislocations bend and try to understand why. The analysed islands have always the same hexagonal shape, limited by {0110} facets. The a type dislocations are found to fold many times from basal to the prismatic plane, whereas when a+c dislocations bend to the basal plane, they were not seen to come back to a prismatic one.

scholarly journals Arsenic in Chemical and Metallurgical Conversions of Copper-zinc Concentrates

2020 ◽  
Author(s):  
Evgeny Nikolaevich Selivanov ◽  
Dmitry Olegovich Novikov ◽  
Vyacheslav Vasi- Lyevich Belyaev ◽  
Gennady Veniaminovich Skopov
Keyword(s):  
Sulfuric Acid ◽  
Electrostatic Precipitator ◽  
Metallic Copper ◽  
Gas Treatment ◽  
Sulfuric Acid Production ◽  
Keywords Arsenic ◽  
Copper Zinc ◽  
Sulfide Concentrates ◽  
Impurity Elements

Due to the deterioration of the quality of obtained sulfide-copper concentrates, arsenic circulates and accumulates in the intermediate products, which reduces the quality of the metal and associated product – sulfuric acid. A method of estimation the distribution of impurity elements can be created using the recycling of sulfide concentrates by various technologies (including autogenous smelting, matte conversion and flotation of slags). This technique is based on solving balance equations for iron, copper and arsenic with known compositions of the resulting products. The obtained data were used to assess of the extraction of arsenic into produce outputs (slag, matte, dust, etc.). In this study, the concentration of arsenic in the dust of metallurgical processes and sludge for cleaning acid solutions is confirmed. The increased temperature in the electrostatic precipitator of gas purification of autogenous processes lead to a partial transition of arsenic into the gas stream directed to the sulfuric acid production. It is possible to regulate the fraction of transition of arsenic to dust and sulfuric acid while changing the operating temperature in the electrostatic precipitator. To a lesser extent arsenic is concentrated in the tails of flotation of slag (11.7%) and metallic copper (2.9%). These data are useful for substantiating measures for the wastes recycling and improvement of the ecological environment in the enterprise operating districts. Keywords: arsenic, autogenous melting, matte conversion, slag flotation, purified gas treatment, distribution, dust, sludge

scholarly journals Interaction of landscape space and indoors in architecture of the open-air concert hall “Mitava”

2021 ◽  
Vol 17 ◽  
pp. 55-67
Author(s):  
Aija Grietena
Keyword(s):  
Interdisciplinary Collaboration ◽  
Building Structures ◽  
Acoustic Characteristics ◽  
Concert Hall ◽  
Emotional Quality ◽  
Indoor Space ◽  
The Baltic ◽  
Wooden Structures

In the search for balancing factors in the art of environmental design between architecture, landscape architecture, and interiors needed to improve interdisciplinary collaborative planning and enhance the psycho-emotional quality of the environment, the study of landscape space-indoor interaction through comparative analysis and inductive reference is continued. On the Latvian scale, the new, 21st-century technological capabilities in the design and production of wooden structures in the architecture of the open air concert hall “Mītava”, constructed in 2019 on Pasta Island. The importance of the structure on the Baltic scale is emphasized by the unique design, which resembles a shell washed on the bank of the Lielupe River, large (<60m) arched timber continuous roof structures and high acoustic characteristics. Original building structures have opened up new opportunities for interaction between landscape space and indoor space, creating a broad, spatial synthesis. The realization of an artistically stylistic concept in the open-air concert hall “Mītava”, which is subordinated to the existing landscape space and supplemented with appropriate greenery, is considered a valuable contribution to the urban environment. The specific case study analyzed in detail underlines the importance of successful interdisciplinary collaboration in the harmonious interaction between landscape space and indoor.

scholarly journals A Study on the Characteristics of Chemical Accidents and Reduction of Accidents in Jeollabuk-do

2020 ◽  
Vol 34 (2) ◽  
pp. 49-53
Author(s):  
Jae-Uk Jeong ◽  
Chong-Eun Park
Keyword(s):  
Adverse Reaction ◽  
Sulfuric Acid ◽  
Silicon Tetrachloride ◽  
Government Support ◽  
Safety Education ◽  
Chemical Accidents ◽  
Vehicle Accidents ◽  
Transport Vehicle ◽  
And Training

This study aimed to identify the characteristics of 40 chemical accidents that occurred in Jeollabuk-do from 2004 to 2019. During this time, there were 2.5 accidents per year on average in the province; their types were classified as spill/leak, fire, explosion, adverse reaction, and complex. There were 34 leaks and six explosions, and they are categorized as follows: 12 by worker error, 16 from facility defects, and 12 by transport vehicle accidents. The substances involved in these accidents were ammonia (15%), sulfuric acid (12.5%), and silicon tetrachloride (7.5%). Notably, the rate of chemical accidents (75%) is the highest during spring and summer. In order to reduce chemical accidents, first, there should be compliance with the relevant laws. Second, the quality of safety education and training of workers should be improved. Finally, valuable government support is also necessary to improve facilities.

Who Made Mauveine First: Runge, Fritsche, Beissenhirtz or Perkin?

2016 ◽  
Vol 40 (12) ◽  
pp. 758-762
Author(s):  
M. John Plater ◽  
Andrea Raab
Keyword(s):  
Sulfuric Acid ◽  
Potassium Dichromate ◽  
Original Method

The oxidation of aniline or a mixture of aniline with o-toluidine and p-toluidine following Runge's original method as carefully as possible, using chloride of lime [Ca(OCl)2], produces a coloured solution from which small amounts of mauveine were purified, isolated and analysed by LC-MS. The oxidation of aniline by the method of Fritsche and Beissenhirtz, using potassium dichromate and sulfuric acid, similar to W.H. Perkin's patented method, also gave small quantities of mauveine. The composition of the anilines are suggested depending upon their sources and Kekulé's comments on these early contributions are summarised.

Study of Properties of Multicomponent Heterostructures Based on AIIIBV Compounds

2017 ◽  
Vol 265 ◽  
pp. 728-733 ◽  
Author(s):  
M.L. Lunina ◽  
A.E. Kazakova ◽  
D.A. Arustamyan
Keyword(s):  
Temperature Gradient ◽  
Complex Analysis ◽  
Lattice Parameters ◽  
Epitaxial Layers ◽  
Structural Perfection ◽  
Gradient Zone ◽  
Substrate Orientation ◽  
Zone Recrystallization

Complex analysis of the quality of the surface of the multicomponent epitaxial layers AIIIBV compounds grown at the different conditions of temperature gradient zone recrystallization was performed. Main parameters that determine the quality of the surface and structural perfection of multicomponent heterostructures AlInGaPAs / GaAs have been found: the temperature gradient, the composition of the solution-melt, subcooling, matching the lattice parameters and the CTE of the layer and the substrate, the substrate orientation.

Heat and Mass Transfer during Drying of Clay Ceramic Materials: A Three-Dimensional Analytical Study

2017 ◽  
Vol 10 ◽  
pp. 93-106 ◽  
Author(s):  
M.K. Teixeira de Brito ◽  
D.B. Teixeira de Almeida ◽  
A.G. Barbosa de Lima ◽  
L. Almeida Rocha ◽  
E. Santana de Lima ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Analytical Study ◽  
Separation Of Variables ◽  
Three Dimensional ◽  
Ceramic Materials ◽  
Governing Equations ◽  
Convective Boundary ◽  
Good Agreement

This work aims to study heat and mass transfer in solids with parallelepiped shape with particular reference to drying process. A transient three-dimensional mathematical model based on the Fick ́s and Fourier ́s Laws was developed to predict heat and mass transport in solids considering constant physical properties and convective boundary conditions at the surface of the solid. The analytical solution of the governing equations was obtained using the method of separation of variables. The study was applied in the drying of common ceramic bricks. Predicted results of the heating and drying kinetics and the moisture and temperature distributions inside the material during the process, are compared with experimental data and good agreement was obtained. It has been found that the vertices of the solid dry and heat first. This provokes thermal and hydric stresses inside the material, which may compromise the quality of the product after drying.

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