Detailed Kinetics Modeling of Indium Phosphide Films in Mocvd Reactors

1997 ◽  
Vol 485 ◽  
Author(s):  
Maurizio Masi ◽  
Carlo Cavallotti ◽  
Guido Radaelli ◽  
S. Carrà
Keyword(s):  
Boundary Layer ◽  
Indium Phosphide ◽  
Gas Phase ◽  
Dissociative Adsorption ◽  
Boundary Layer Theory ◽  
Chemical Mechanism ◽  
Deposition Kinetics ◽  
Detailed Kinetics ◽  
Kinetics Of ◽  
Dual Site

AbstractThe deposition kinetics of InP in MOCVD reactors is presented. The proposed chemical mechanism involves both gas phase and surface reactions. The fundamental hypothesis adopted in deriving the mechanism was a dual site dissociative adsorption of the precursors on the growing surface. In any case, all the rate constants either were taken from the literature or estimated through thermochemical methods. In addition, the deposition reactor was simulated by means of a monodimensional model that accounts for the main reactor features through the boundary layer theory.

Predicting the kinetics of the dissociative adsorption of homonuclear molecules on metal surfaces in gas phase and solution

2004 ◽  
Vol 554 (2-3) ◽  
pp. 159-169 ◽  
Author(s):  
Ernst D. German ◽  
Alexander M. Kuznetsov ◽  
Moshe Sheintuch
Keyword(s):  
Gas Phase ◽  
Metal Surfaces ◽  
Dissociative Adsorption ◽  
Kinetics Of

scholarly journals Radicals in the marine boundary layer during NEAQS 2004: a model study of day-time and night-time sources and sinks

2009 ◽  
Vol 9 (9) ◽  
pp. 3075-3093 ◽  
Author(s):  
R. Sommariva ◽  
H. D. Osthoff ◽  
S. S. Brown ◽  
T. S. Bates ◽  
T. Baynard ◽  
...  
Keyword(s):  
Boundary Layer ◽  
New England ◽  
Gas Phase ◽  
Marine Boundary Layer ◽  
Peroxy Radical ◽  
Chemical Mechanism ◽  
Physical Parameters ◽  
Peroxy Radicals ◽  
Night Time ◽  
Aerosol Composition

Abstract. This paper describes a modelling study of several HOx and NOx species (OH, HO2, organic peroxy radicals, NO3 and N2O5) in the marine boundary layer. A model based upon the Master Chemical Mechanism (MCM) was constrained to observations of chemical and physical parameters made onboard the NOAA ship R/V Brown as part of the New England Air Quality Study (NEAQS) in the summer of 2004. The model was used to calculate [OH] and to determine the composition of the peroxy radical pool. Modelled [NO3] and [N2O5] were compared to in-situ measurements by Cavity Ring-Down Spectroscopy. The comparison showed that the model generally overestimated the measurements by 30–50%, on average. The model results were analyzed with respect to several chemical and physical parameters, including uptake of NO3 and N2O5 on fog droplets and on aerosol, dry deposition of NO3 and N2O5, gas-phase hydrolysis of N2O5 and reactions of NO3 with NMHCs and peroxy radicals. The results suggest that fog, when present, is an important sink for N2O5 via rapid heterogeneous uptake. The comparison between the model and the measurements were consistent with values of the heterogeneous uptake coefficient of N2O5 (γN2O5)>1×10−2, independent of aerosol composition in this marine environment. The analysis of the different loss processes of the nitrate radical showed the important role of the organic peroxy radicals, which accounted for a significant fraction (median: 15%) of NO3 gas-phase removal, particularly in the presence of high concentrations of dimethyl sulphide (DMS).

scholarly journals The influence of cloud chemistry on HO<sub>x</sub> and NO<sub>x</sub> in the Marine Boundary Layer: a 1-D modelling study

2001 ◽  
Vol 1 (2) ◽  
pp. 277-335
Author(s):  
J. E. Williams ◽  
F. J. Dentener ◽  
A. R. van den Berg
Keyword(s):  
Boundary Layer ◽  
Gas Phase ◽  
Marine Boundary Layer ◽  
Phase Transfer ◽  
Cloud Model ◽  
Chemical Mechanism ◽  
Marine Stratocumulus ◽  
Modelling Studies ◽  
A Minor ◽  
The Impact

Abstract. A 1-D marine stratocumulus cloud model has been supplemented with a comprehensive and up-to-date aqueous phase chemical mechanism for the purpose of assessing the impact that the presence of clouds and aerosols has on gas phase HOx, NOx and O3 budgets in the marine boundary layer. The simulations presented here indicate that cloud may act as a heterogeneous source of HONOg via the conversion of HNO4(g) at moderate pH (~4.5). The photolysis of nitrate (NO3-) has also been found to contribute to this simulated increase in HONOg by ~5% and also acts as a minor source of NO2(g). The effect of introducing deliquescent aerosol on the simulated increase of HONOg is negligible. The most important consequences of this elevation in HONOg are that, in the presence of cloud, gas phase concentrations of NOx species increase by a factor of 2, which minimises the simulated decrease in O3(g), and results in a regeneration of OHg. This partly compensates for the removal of OHg by direct phase transfer into the cloud and has important implications regarding the oxidising capacity of the marine boundary layer. The findings presented here also suggest that previous modelling studies, which neglect the heterogeneous HNO4(g) reaction cycle, may have over-estimated the role of clouds as a sink for OHg and O3(g)in unpolluted oceanic regions, by ~10% and ~2%, respectively.

scholarly journals The influence of cloud chemistry on HO<sub>x</sub> and NO<sub>x</sub> in the moderately polluted marine boundary layer: a 1-D modelling study

2002 ◽  
Vol 2 (1) ◽  
pp. 39-54 ◽  
Author(s):  
J. E. Williams ◽  
F. J. Dentener ◽  
A. R. van den Berg
Keyword(s):  
Boundary Layer ◽  
Gas Phase ◽  
Marine Boundary Layer ◽  
Phase Transfer ◽  
Cloud Model ◽  
Chemical Mechanism ◽  
Cloud Chemistry ◽  
Marine Stratocumulus ◽  
The Impact ◽  
Heterogeneous Source

Abstract. A 1-D marine stratocumulus cloud model has been supplemented with a comprehensive and up-to-date aqueous phase chemical mechanism for the purpose of assessing the impact that the presence of clouds has on gas phaseHOx, NOx and O3 budgets in the marine boundary layer. The simulations presented here indicate that cloud may act as a heterogeneous source of HONOg. The conversion of HNO4(g) at moderate pH (~ 4.5) is responsible for this, and, to a lesser extent, the photolysis of nitrate (NO3-). The effect of introducing deliquescent aerosol on the simulated increase of HONOg is negligible. The most important consequences of this elevation in HONOg are that, in the presence of cloud, gas phase concentrations of NOx species increase by a factor of 2, which minimises the simulated decrease in O3(g), and results in a regeneration of OHg. This partly compensates for the removal of OHg by direct phase transfer into the cloud and may have important implications regarding the oxidising capacity of the marine boundary layer.

scholarly journals Mathematical modelling of burning surface in parallel flow of oxidant

2018 ◽  
Vol 209 ◽  
pp. 00007 ◽  
Author(s):  
Veronika Tyurenkova ◽  
Nickolay Smirnov ◽  
Mariya Smirnova
Keyword(s):  
Boundary Layer ◽  
Laminar Flow ◽  
Gas Phase ◽  
Burning Surface ◽  
Boundary Layer Theory ◽  
Material Surface ◽  
Condensed Material ◽  
Surface Burning ◽  
And Diffusion ◽  
Phase Chemical

The paper presents the problem of condensed material surface burning in a flow of oxidant within the framework of the assumptions of the laminar boundary-layer theory. It is used assumption of fuel gasification and gas phase chemical reacting in a diffusion flame. The regression rate of the material surface in the turbulent and laminar flow regimes is studied. The zones correspond to kinetic and diffusion regime is defined.

Kinetic Evaluation of Carbon Formation in Steam/CO2-Natural Gas Reformers. Influence of the Catalyst Activity and Alkalinity

2002 ◽  
Vol 1 (1) ◽  
Author(s):  
Joost-Willem Snoeck ◽  
Gilbert Froment ◽  
Martin Fowles
Keyword(s):  
Natural Gas ◽  
Gas Phase ◽  
Catalyst Activity ◽  
Accurate Determination ◽  
Activity Level ◽  
Carbon Formation ◽  
Kinetic Evaluation ◽  
Detailed Kinetics ◽  
Kinetics Of

The production of synthesis gas with a low H2/CO ratio from natural gas requires recycling the produced CO2, but this enhances the risk of carbon formation. A simulation model for steam/CO2 reformers comprising detailed kinetics of the main reactions but also of the carbon formation and gasification was used to evaluate the potential of carbon formation in the bulk gas phase and inside the catalyst particles along the reactor tube. Simulation results are presented for a number of cases with varying amounts of CO2 in the feed. The model permits an accurate determination of the minimum amount of steam or the maximum amount of CO2 that can be tolerated in the feed. Thermodynamic and kinetic criteria are compared, and a strategy for the evaluation of the risk of carbon formation is proposed. The importance of the activity level of the catalyst and of its alkalinity is also illustrated.

scholarly journals Radicals in the marine boundary layer during NEAQS 2004: a model study of day-time and night-time sources and sinks

2008 ◽  
Vol 8 (4) ◽  
pp. 16643-16692 ◽  
Author(s):  
R. Sommariva ◽  
H. D. Osthoff ◽  
S. S. Brown ◽  
T. S. Bates ◽  
T. Baynard ◽  
...  
Keyword(s):  
Boundary Layer ◽  
New England ◽  
Gas Phase ◽  
Marine Boundary Layer ◽  
Peroxy Radical ◽  
Chemical Mechanism ◽  
Physical Parameters ◽  
Peroxy Radicals ◽  
Night Time ◽  
Aerosol Composition

Abstract. This paper describes a modelling study of several HOx and NOx species (OH, HO2, organic peroxy radicals, NO3 and N2O5) in the marine boundary layer. A model based upon the Master Chemical Mechanism (MCM) was constrained to observations of chemical and physical parameters made onboard the NOAA ship R/V Brown as part of the New England Air Quality Study (NEAQS) in the summer of 2004. The model was used to calculate [OH] and to determine the composition of the peroxy radical pool. Modelled [NO3] and [N2O5] were compared to in-situ measurements by Cavity Ring-Down Spectroscopy. The comparison showed that the model generally overestimated the measurements by 30–50%, on average. The model results were analyzed with respect to several chemical and physical parameters, including uptake of NO3 and N2O5 on fog droplets and on aerosol, dry deposition of NO3 and N2O5, gas-phase hydrolysis of N2O5 and reactions of NO3 with NMHCs and peroxy radicals. The results suggest that fog, when present, is an important sink for N2O5 via rapid heterogeneous uptake. The comparison between the model and the measurements were consistent with values of the heterogeneous uptake coefficient of N2O5 (γN2O5)>1×10−2, independent of aerosol composition in this marine environment. The analysis of the different loss processes of the nitrate radical showed the important role of the organic peroxy radicals, which accounted for a significant fraction (median: 15%) of NO3 gas-phase removal, particularly in the presence of high concentrations of dimethyl sulphide (DMS).

Detailed kinetics of methylphenyldichlorosilane synthesis from methyldichlorosilane and chlorobenzene by gas phase condensation

2015 ◽  
Vol 23 (6) ◽  
pp. 954-961
Author(s):  
Tong Liu ◽  
Tiefeng Wang ◽  
Yunlong Huang ◽  
Chao Wang ◽  
Jinfu Wang
Keyword(s):  
Gas Phase ◽  
Detailed Kinetics ◽  
Kinetics Of
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