scholarly journals Growth Kinetics of Thin Film Epitaxy

2020 ◽  
Author(s):  
Hong Liu
Keyword(s):  
Growth Stage ◽  
Deposition Process ◽  
Film Structure ◽  
Film Deposition ◽  
Diffusion Reaction ◽  
Growth Modes ◽  
Adsorption Surface ◽  
The Relationship ◽  
Thin Film Epitaxy ◽  
Kinetics Of

This chapter mainly introduces five basic stages of the film deposition process (vapor adsorption, surface diffusion, reaction between adsorbed species, reaction of film materials to form bonding surface, and nucleation and microstructure formation), analyzes the influence of deposition process parameters on the three basic growth modes of the film, focuses on the relationship between the control parameters of homoepitaxy and heteroepitaxy and the film structure, gives the dynamic characteristics of each growth stage, and examines the factors determining epitaxy film structure, topography, interfacial properties, and stress. It is shown that two-dimensional nucleation is a key to obtain high-quality epitaxial films.

scholarly journals Kinetics of extraction from water solutions of Fe3+, Cu2+ and Pb2+ + ions by filter loading, obtained by blinding plasters

2020 ◽  
pp. 76-80
Author(s):  
A. I. Teran
Keyword(s):  
Deposition Process ◽  
Reaction Products ◽  
Maximum Probability ◽  
Continuous Layer ◽  
Steelmaking Slags ◽  
Initial Stage ◽  
Formal Kinetic ◽  
Filter Loading ◽  
The Relationship ◽  
Kinetics Of

In this study, we investigated the kinetics of extraction from aqueous solutions of Fe3+, Cu2+ and Pb2+ by filter loadings, derived from the steelmaking slags. A formal kinetic approach based on the relationship between the relative deposition rate (α) and time (τ) was used to estimate the mechanism and kinetic parameters of the deposition process). From the set of equations are selected those that in a given region of the degree of completion of the process gave the minimum value of the variance, that is, described the process in the system at this stage with the maximum probability. Three models that best correspond to real processes are selected. It was found that the deposition process at the initial stage limits the chemical stage of nucleation (formation of crystalline precipitate), then – the reaction at the interface (formation of a continuous layer of reaction products on the surface of the nuclei), and at the final stage – the growth of a continuous layer of reaction products.

scholarly journals Growth Kinetics of Monodisperse Polystyrene Microspheres Prepared by Dispersion Polymerization

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Fan Li ◽  
Chong Geng ◽  
Qingfeng Yan
Keyword(s):  
Dispersion Polymerization ◽  
Growth Stage ◽  
Initial Conditions ◽  
Monomer Concentration ◽  
Polymerization Process ◽  
Colloidal Spheres ◽  
Size Evolution ◽  
Micron Size ◽  
The Relationship ◽  
Kinetics Of

Dispersion polymerization has been widely applied to the synthesis of monodisperse micron-sized polymer colloidal spheres. Many efforts have been devoted to studying the influence of initial conditions on the size and uniformity of the resultant microspheres, aiming to synthesize micron-size monodisperse colloidal spheres. However, the inner contradiction between the size and the size distribution of colloidal spheres hinders the realization of this goal. In this work, we drew our attention from the initial conditions to the growth stage of dispersion polymerization. We tracked the size evolution of colloidal sphere during the dispersion polymerization, through which we established a kinetic model that described the relationship between the monomer concentration and the reaction time. The model may provide a guideline to prepare large polymer colloidal spheres with good monodispersity by continuous monomer feeding during the growth stage to maintain the concentration of monomer at a constant value in a dispersion polymerization process.

Vertically self-organized gold nanoparticles in amorphous alumina matrices

2006 ◽  
Vol 960 ◽  
Author(s):  
Chunming Jin ◽  
Honghui Zhou ◽  
Wei Wei ◽  
Roger J. Narayan
Keyword(s):  
Gold Nanoparticles ◽  
Vertical Direction ◽  
Deposition Process ◽  
Film Deposition ◽  
Multilayered Structures ◽  
Cross Sectional ◽  
Self Organized ◽  
Growth Modes ◽  
Transmission Electron ◽  
Amorphous Alumina

ABSTRACTIn this study, self-organized growth of gold nanoparticles dispersed in amorphous alumina matrices was investigated. Au/Al2O3 multilayered structures were grown on silicon (001) substrates using pulsed laser deposition. Vertical ordering of particles was examined with cross-sectional transmission electron microscopy and image Fourier transformation. Self-organization of gold nanoparticles along the vertical direction was observed in the samples grown at room temperature and 320 °C. This process occurred through two-different growth modes, known as top-on-top growth and top-on-middle growth. The driving force for the vertical ordering was attributed to long-range elastic interactions among nanoparticles during the film deposition process.

Diffusion model for deposition of epitaxial GaAs layers prepared by the MOCVD method

1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Kinetic Model ◽  
Gas Phase ◽  
Substrate Surface ◽  
Deposition Process ◽  
Hydrogen Atmosphere ◽  
Epitaxial Gaas ◽  
Kinetics Of ◽  
Good Agreement

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.

Cooperation between universities and SMEs: A systematic literature review

2021 ◽  
pp. 095042222199511
Author(s):  
Rosivalda Pereira ◽  
Mário Franco
Keyword(s):  
Literature Review ◽  
Systematic Literature Review ◽  
Growth Stage ◽  
Innovation System ◽  
Objective Data ◽  
Main Difficulty ◽  
Study Objective ◽  
Cooperative Relationships ◽  
Scopus Database ◽  
The Relationship

This study aims to present the relationship between universities and small and medium-sized enterprises (SMEs) through a systematic literature review. SMEs play an important role in economic development. Similarly, universities are important actors in the innovation system. To fulfil the study objective, data were collected from the Scopus database. The bibliometric results found, using bibliometrix software, reveal that this topic first appeared in the literature in 1995 and entered a growth stage in 2014. Systematically, studies have focused mostly on European countries and the emphasis in cooperation is on knowledge transfer. In addition, the results show that SMEs form cooperative relationships with universities in search of competitive results. However, the main difficulty with regard to the establishment of such relationships is a lack of knowledge in SMEs about university programmes that can support them and about how to access such programmes. Therefore, it is suggested that universities should establish more effective communication channels in order to reach this type of firm.

Study on leaching kinetics of hexavalent chromium from aged calcium-free chromium slag

2021 ◽  
pp. 1-13
Author(s):  
Quan Qi ◽  
Liang Li ◽  
Liangyu Wei ◽  
Baoming Hu ◽  
Zheng Liu ◽  
...  
Keyword(s):  
Hexavalent Chromium ◽  
Resource Utilization ◽  
Scientific Basis ◽  
Diffusion Reaction ◽  
Leaching Kinetics ◽  
Leaching Rate ◽  
Chromium Slag ◽  
Leaching Solution ◽  
Main Components ◽  
Kinetics Of

To provide a scientific basis for the resource utilization of chromium slag, this article studies the release law of hexavalent chromium in the aged calcium-free chromium slag. XRD (X-ray diffractometer) and MLA (Mineral Liberation Analyzer) were used to analyze the composition of the chromium slag; using sulfuric acid-nitric acid as the leaching solution, the release law of hexavalent chromium in chromium slag and the leaching kinetics were studied. The results show that main components of the chromium slag are magnesioferrite, chromite, hematite, hydrargillite, and spinel; chromium is mainly present in chromite and magnesioferrite; the leaching rate of hexavalent chromium increases with the increase of temperature or the decrease of pH. The analysis of leaching kinetics shows the leaching rate is controlled by the internal diffusion reaction, and the apparent activation energy is 11.93 kJ·mol–1. The chromium slag is aged in high temperature seasons, which is conducive to the precipitation of hexavalent chromium in the chromium slag, can increase the yield of chromate in the roasting kiln, and is conducive to resource utilization; chromium slag should be stored in order to prevent acid rain erosion which leads to environmental pollution risk (e.g. drinking water).

Oxidation of Olefins Representing Some Structural Units of GR-S

1952 ◽  
Vol 25 (1) ◽  
pp. 21-32 ◽  
Author(s):  
W. C. Warner ◽  
J. Reid Shelton
Keyword(s):  
Phenyl Group ◽  
Kinetic Mechanism ◽  
Oxidation Reactions ◽  
Chain Reaction ◽  
Instantaneous Rate ◽  
Initial Oxygen ◽  
Oxidation Of Olefins ◽  
A Minor ◽  
The Relationship ◽  
Kinetics Of

Abstract Three olefins were oxidized in the liquid phase with molecular oxygen to determine the kinetics of the oxidation reactions and the relationship to oxidation of rubber. The instantaneous rate of oxidation was found to be related to the analytically determined olefin and peroxide concentrations by the equation : Rate=k (unreacted olefin)(peroxide), where rate equals moles of oxygen per mole of original olefin per hour and the parentheses represent molarities. Presence of a phenyl group was found to affect k, but only in a minor way, indicating that the same fundamental kinetic mechanism applies in both aromatic and aliphatic olefins. The data are consistent with the general kinetic mechanism of Bolland involving oxygen attack at the alpha-methylenic group. However, it appears probable that initial oxygen attack can also occur at the double bond, resulting in the formation of a peroxide biradical, which may then react with other olefin molecules, initiating the usual chain reaction mechanism.

CORRELATION BETWEEN ELECTRIC CHARGING OF THE SAMPLE SURFACE AND KINETICS OF OPTICALLY STIMULATED EXOELECTRON EMISSION (OSEE) FROM CRYOSOLIDIFIED NaCl SOLUTION

1990 ◽  
Vol 04 (03) ◽  
pp. 201-209
Author(s):  
A. GIEROSZYŃSKI
Keyword(s):  
Electric Fields ◽  
Surface Potential ◽  
Surface Region ◽  
Sample Surface ◽  
Exoelectron Emission ◽  
Nacl Solution ◽  
Emitter Surface ◽  
Emitter Layer ◽  
The Relationship ◽  
Kinetics Of

It was found that OSEE kinetics from electron bombarded cryosolidified NaCl solution, depend on electric charging of the sample surface. It was shown that from the relationship between the maximum surface potential and the parameters of OSEE kinetic, intensities of electric fields in the emitter layer could be estimated. It is supposed that nonhomogeneous electric fields existing in the emitter surface region, influence the emission levels responsible for the course of OSEE kinetics.

Development of Thin Metal Film Deposition Process for the Intravascular Catheter

1999 ◽  
Author(s):  
Seok Chung ◽  
Jun Keun Chang ◽  
Dong Chul Han
Keyword(s):  
Metal Film ◽  
Three Dimensional ◽  
Deposition Process ◽  
Medical Application ◽  
Thin Metal Film ◽  
Film Deposition ◽  
Thin Metal ◽  
Mems Devices ◽  
Sensors And Actuators ◽  
Custom Made

Abstract To make some MF.MS devices such as sensors and actuators be useful in the medical application, it is required to integrate this devices with power or sensor lines and to keep the hole devices biocompatible. Integrating micro machined sensors and actuators with conventional copper lines is incompatible because the thin copper lines are not easy to handle in the mass production. To achieve the compatibility of wiring method between MEMS devices, we developed the thin metal film deposition process that coats micropattered thin copper films on the non silicon-wafer substrate. The process was developed with the custom-made three-dimensional thin film sputter/evaporation system. The system consists of process chamber, two branch chambers, substrate holder unit and linear/rotary motion feedthrough. Thin metal film was deposited on the biocompatible polymer, polyurethane (PellethaneR) and silicone, catheter that is 2 mm in diameter and 1,000 mm in length. We deposited Cr/Cu and Ti/Cu layer and made a comparative study of the deposition processes, sputtering and evaporation. The temperature of both the processes were maintained below 100°C, for the catheter not melting during the processes. To use the films as signal lines connect the signal source to the actuator on the catheter tip, we machined the films into desired patterns with the eximer laser. In this paper, we developed the thin metal film deposition system and processes for the biopolymeric substrate used in the medical MEMS devices.

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