Modeling of nonlinear processes of nucleation and growth of GaSxSe1–x(0 ≤ х≤ 1) solid solutions

The results on the study of modeling and physico-chemical study of the kinetics ofnucleation and growth of GaSxSe1–x(0 ≤ х≤ 1) solid solution. The nucleation heterogeneous process and growth of GaSxSe1–xcrystals have been studied and simulated taking into account nonlinear equations considering the kinetic behavior of crystallizing phases.GaSxSe1–xsingle and nanocrystals were grown from solution, melt, and by chemical transport reaction through steam. GaSxSe1–xcrystals were grownbychemical transport reaction in a two-tem-perature gradient furnace in a sealed quartz ampoule. Iodine was used as a transporting additive. Using the Fokker–Planck equation, the evolution of the distribution function of crystals of solid solutions of the GaS–GaSe system by size at the nucleation time is studied by a numerical method. For the convenience of comparing theory with experimental data, we used the GaS1–xSex(x= 0.7 molar fraction of GaSe) composition of the solid solution. The Monte Carlo method is used to approximate the time evolution of the nucleation of two types of particles for the GaS0.3Se0.7 solid solution, simulated by a constant nucleus size. The results of modeling non-linear crystallization processes are consistent with experimental data.

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Подавление температурной зависимости длины волны излучения в светодиодных структурах со ступенчатым гетеропереходом II типа InAsSb/InAsSbP

Физика и техника полупроводников ◽

10.21883/ftp.2021.03.50607.9549 ◽

2021 ◽

Vol 55 (3) ◽

pp. 277

Author(s):

А.А. Семакова ◽

В.В. Романов ◽

Н.Л. Баженов ◽

К.Д. Мынбаев ◽

К.Д. Моисеев

Keyword(s):

Experimental Data ◽

Solid Solution ◽

Active Region ◽

Molar Fraction ◽

Type Ii ◽

Ternary Solid Solution ◽

Dominant Contribution ◽

Temperature Range ◽

Radiative Transitions ◽

Operating Wavelength

The results of a study of the electroluminescence of the asymmetric InAs/InAs1−ySby/InAsSbP LED heterostructures with a molar fraction of InSb in the ternary solid solution in the active region y=0.15 and y=0.16 in the temperature range 4.2−300 K are presented. Based on the experimental data, the formation of a staggered type II heterojunction at the InAs1−ySby/InAsSbP heterointerface was determined. The dominant contribution of the interface radiative transitions at the type II heterointerface in the temperature range 4.2−180 K was shown, which makes it possible to minimize the temperature dependence of the operating wavelength of the LEDs.

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Facile Synthesis of ZnxCd1-xS Solid Solution Microspheres through Ultrasonic Spray Pyrolysis for Improved Photocatalytic Activity

Journal of Nanomaterials ◽

10.1155/2017/6356021 ◽

2017 ◽

Vol 2017 ◽

pp. 1-8 ◽

Cited By ~ 2

Author(s):

Jianhui Huang ◽

Wenting Lin ◽

Liyan Xie ◽

Wingkei Ho

Keyword(s):

Electron Microscopy ◽

Solid Solution ◽

Spray Pyrolysis ◽

Solid Solutions ◽

Molar Fraction ◽

Ultrasonic Spray Pyrolysis ◽

Mesoporous Structure ◽

Practical Applications ◽

Ultrasonic Spray ◽

Transmission Electron

Nanocrystal ZnxCd1-xS solid solutions were successfully prepared using a facile and reproducible method of ultrasonic spray pyrolysis with Cd(Ac)2·2H2O, ZnCl2, and thiourea as precursors. Scanning electron microscopy and transmission electron microscopy images show that the prepared particles possess microspherical morphology. The band gaps of the solid solutions can be tuned by changing the constituent stoichiometries of Cd and Zn. The X-ray diffraction peaks gradually shift to small angle, and the absorption edge shifts to long wavelength with increasing Cd molar fraction in the solid solution. The sample prepared at the Cd/Zn ratio of 1 : 1 displays the optimal activity by using the photocatalytic degradation of methyl orange in the aqueous solution as model reactions under visible light irradiation. This study provides an effective route to prepare spherical ternary photocatalysts with mesoporous structure for further investigations and practical applications.

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Crystal growth of the corundum-type iron and chromium oxide solid solution by chemical transport reaction

Journal of Crystal Growth ◽

10.1016/0022-0248(80)90295-x ◽

1980 ◽

Vol 49 (4) ◽

pp. 687-692 ◽

Cited By ~ 4

Author(s):

K. Hayashi ◽

A.S. Bhalla ◽

R.E. Newnham ◽

L.E. Cross

Keyword(s):

Solid Solution ◽

Crystal Growth ◽

Chromium Oxide ◽

Chemical Transport ◽

Chemical Transport Reaction ◽

Transport Reaction ◽

Oxide Solid Solution

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Thermodynamic Modelling and Aqueous Chemistry in the CaO-Al2O3-SiO2-H2O System

MRS Proceedings ◽

10.1557/proc-212-395 ◽

1990 ◽

Vol 212 ◽

Cited By ~ 3

Author(s):

A. Atkinson ◽

J. A. Hearne ◽

C. F. Knights

Keyword(s):

Experimental Data ◽

Solid Solution ◽

Radioactive Waste ◽

Solid Solutions ◽

Chemical Properties ◽

Average Composition ◽

Radioactive Waste Repositories ◽

Waste Repositories ◽

Hydrolysis Of ◽

Main Influence

ABSTRACTThe chemical properties of the CaO-Al2O3-SiO2-H2O system are important for understanding and predicting the behaviour of Portland cements in cementitious wasteforms and radioactive waste repositories. Solids of known average composition in this system have been synthesised by the co-hydrolysis of mixed alkoxides. The solids have been equilibrated with water at 25°C and the composition of the aqueous phase characterised. A thermodynamic model for the system has been developed by extending an earlier model of solid solutions in amorphous gels to include aluminium compounds. The model accounts for most of the experimental data and predicts that the main influence of aluminium is to form a hydrogarnet solid solution of general composition C3AH6−2xSx The model can be used to predict the chemistry of hydrated cements and the interaction of cements with groundwaters.

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Chemical Polishig of CdTe and Solid Solution ZnxCd1-xTe and Cd0.2Hg0.8Te by the HNO3 – НІ – Glycerin Acid Aqueous Solutions

Фізика і хімія твердого тіла ◽

10.15330/pcss.18.1.117-121 ◽

2017 ◽

Vol 18 (1) ◽

pp. 117-121

Author(s):

E.E. Hvozdiyevskyi ◽

R.O. Denysyuk ◽

V.M. Tomashyk ◽

Z.F. Tomashyk

Keyword(s):

Experimental Data ◽

Solid Solution ◽

Aqueous Solutions ◽

Dissolution Rate ◽

Single Crystals ◽

Solid Solutions ◽

Etching Rate ◽

Organic Content ◽

Chemical Dissolution

The chemical dissolution of the CdTe, ZnxCd1-xTe and Cd0,2Hg0,8 solid solutions single crystals in the HNO3 – HI – glycerin aqueous solutions has been investigated. The etching rate dependences of the mentioned above materials versus the iodine and organic content in the compositions and the kinetic peculiarities of the chemical dissolution have been determined. It was established that the dissolution rate of the semiconductor solid solutions in the HNO3 – HI – glycerin etchant compositions decreases with the increasing of oxidizer and glycerin. Using experimental data, the compositions of polishing solutions and the conditions of chemical-dynamic polishing of the CdTe, ZnxCd1-xTe and Cd0,2Hg0,8Te surfaces have been optimized.

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Muscovite solid solutions in the system K2O-MgO-FeO-Al2O3-SiO2-H2O: an experimental study at 2 kbar PH2O and comparison with natural Li-Free white micas

Mineralogical Magazine ◽

10.1180/minmag.1986.050.356.08 ◽

1986 ◽

Vol 50 (356) ◽

pp. 257-266 ◽

Cited By ~ 36

Author(s):

Gilles Monier ◽

Jean-Louis Robert

Keyword(s):

Experimental Data ◽

Solid Solution ◽

Experimental Study ◽

High Temperature ◽

Solid Solutions ◽

Granitic Rocks ◽

Formula Unit ◽

Increasing Temperature ◽

Tetrahedral Layer ◽

Layer Composition

AbstractThis paper presents the results of an experimental study of muscovite solid solutions in the system K2O-M2+O-Al2O3-SiO2-H2O-(HF), with M2+ = Mg2+ or Fe2+ in the temperature range 300-700°C under 2 kbar PH2O. Muscovite solid solutions can be described, in this system, as the result of two substitutions. One is the phengitic substitution (x), which preserves the pure dioctahedral character of the mica; the second is the biotitic substitution (y), which leads to trioctahedral micas and does not change the composition of the tetrahedral layer Si3Al. The general formula of muscovite in this system is K(Al2−x−2y∕3M2+x+y□1−y∕3)(Si3+xAl1−x)O10(OH,F)2. Both substitutions x and y are more extensive at lower temperatures. The extent of solid solution decreases drastically with increasing temperature.For T > 600°C, the phengitic substitution (x) becomes negligible, but some biotitic substitution (y) persists. This unsymmetrical decrease of the solid solution of muscovite with increasing temperature is similar to that previously observed in phlogopite, the micas with a tetrahedral layer composition of Si3Al being the most stable. The behaviour of muscovite solid solutions in the ferrous system is qualitatively identical to that observed in the magnesian one, but the extent of solid solution is smaller than with Mg2+. Fluorine neither changes the size nor the shape of the solid solution fields but increases their stability by about 50°C.A comparison of these experimental results with data on natural muscovites is presented. Most natural primary (magmatic) granitic muscovites lie very close to the muscovite end member, in agreement with their high-temperature origin. Low-temperature muscovites (300–400°C), typically muscovites from hydrothermally altered granitic rocks, can have high x and y values. The rate of the biotitic substitution y can reach 0.6, which corresponds to an octahedral occupancy of 2.2 atoms per formula unit (based on 11 oxygens), consistent with the experimental data.

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PHYSICO-CHEMICAL PROPERTIES OF COMPOSITES ON THE BASE OF CERIA OBTAINED BY A CITRIC ACID METHOD

Ukrainian Chemistry Journal ◽

10.33609/0041-6045.85.4.2019.98-109 ◽

2019 ◽

Vol 85 (4) ◽

pp. 98-109

Author(s):

Iryna Romanova ◽

Sviatosla Kirillov

Keyword(s):

Solid Solution ◽

Citric Acid ◽

Low Temperature ◽

Manganese Oxide ◽

Solid Solutions ◽

Chemical Properties ◽

Specific Area ◽

Physico Chemical ◽

Ethanol Combustion ◽

Temperature Programmed

Composites with the formula nMOx–СеО2, where n is the mole part of copper or manganese oxide have been synthesized via citric acid aided route. Physico-chemical properties of materials obtained are investigated by XRD, low temperature desorption of nitrogen and by temperature-programmed reduction (TPR). It is defined that the composites with the n < 0.25 (for Cu) and < 0.75 (Mn) are the solid solutions obtained by the replacement of cerium ions in the structure of fluorite (СеО2) by copper or manganese ions. The existence of the separate phases of oxides such as CuO and Mn3O4 has been identified in the XRD patterns of composites with formula 0.25CuО–СеО2 and 0.75MnOx–СеО2. The parameters of cell and the particles size for all samples are calculated; decreasing these values occurs due to the solid solutions formation. Specific area of composites obtained is much bigger than specific area of individual oxides; the biggest values are determined for the samples containing the biggest part of copper or manganese oxide. According to TPR profiles of composites themaximal intensity of low temperature peak has the composite 0.25CuО–СеО2 that means the biggest part of the solid solution; so this material is the most active in CO and ethanol combustion. This fact can be explained by appearance of additional oxygen vacancies when ions Ce4+ are replacement by ions with the less oxidation state. The quantities of hydrogen used for reduction of samples with the copper oxide and samples with the manganese oxide with n < 0.5 are much bigger than the theoretical values; in this case the reduction of the part of ceria in the solid solution is happened. The composite 0.25MnOx–CeO2 is the most active in the ethanol combustion; full conversion to CO2 is finished at 205°С. The high activity of individual oxide MnOx and the composite 0.75MnOx–СеО2 in the reaction of toluene oxidation explains by the biggest part of Mn3+ ions in their structure among the all oxides investigated.

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Identifying Physico-Chemical Laws from the Robotically Collected Data

10.26434/chemrxiv.8490149 ◽

2019 ◽

Author(s):

Liwei Cao ◽

Danilo Russo ◽

Vassilios S. Vassiliadis ◽

Alexei Lapkin

Keyword(s):

Experimental Data ◽

Numerical Models ◽

Predictor Variable ◽

Physical Models ◽

Training Data ◽

Mixed Integer ◽

Physico Chemical ◽

Data Points ◽

Future Work ◽

The Relationship

A mixed-integer nonlinear programming (MINLP) formulation for symbolic regression was proposed to identify physical models from noisy experimental data. The formulation was tested using numerical models and was found to be more efficient than the previous literature example with respect to the number of predictor variables and training data points. The globally optimal search was extended to identify physical models and to cope with noise in the experimental data predictor variable. The methodology was coupled with the collection of experimental data in an automated fashion, and was proven to be successful in identifying the correct physical models describing the relationship between the shear stress and shear rate for both Newtonian and non-Newtonian fluids, and simple kinetic laws of reactions. Future work will focus on addressing the limitations of the formulation presented in this work, by extending it to be able to address larger complex physical models.

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