Nonlinear chemical reactions in dispersed media: The effect of slow mass exchange on the steady-state of the Schlögl models

1999 ◽  
Vol 110 (9) ◽  
pp. 4505-4513
Author(s):  
V. K. Vanag ◽  
G. Nicolis
Keyword(s):  
Steady State ◽  
Chemical Reactions ◽  
Mass Exchange ◽  
Dispersed Media

Gas Phase Reactions in Horizontal MOCVD Reactors

1987 ◽  
Vol 94 ◽  
Author(s):  
Hitoshi Tanaka ◽  
J. Komeno
Keyword(s):  
Steady State ◽  
Gas Phase ◽  
Chemical Reactions ◽  
Chemical Species ◽  
Kinetic Simulation ◽  
Gas Phase Reactions ◽  
Mocvd Reactor

ABSTRACTWe have applied kinetic simulation to MOCVD chemistry in a horizontal MOCVD reactor. Both chemical reactions and material diffusion are considered. For trimethylgallium decomposition, concentrations of chemical species reach their steady state values which differ largely from the equilibrium values.

CHEMICAL REACTIONS IN ELECTRICAL DISCHARGES: I. THE SPECTRUM OF THE METHANE–OXYGEN SYSTEM AT LOW PRESSURE IN THE POSITIVE COLUMN OF A D-C. GLOW DISCHARGE

1964 ◽  
Vol 42 (8) ◽  
pp. 1792-1810
Author(s):  
Pierre A. Bois D'enghien ◽  
Jacques M. Deckers
Keyword(s):  
Carbon Monoxide ◽  
Steady State ◽  
Glow Discharge ◽  
Chemical Reactions ◽  
Positive Column ◽  
Quantitative Relationship ◽  
Chemical Bonds ◽  
Mechanism Of Formation ◽  
Electrical Discharges ◽  
Oxygen System

A technique is described which permits the study of changes in the spectra emitted by fast flowing reacting gas mixtures in the plasma of the positive column of a weak d-c. glow discharge. In certain cases a quantitative relationship is shown to exist between the concentration of a species and the intensity of emission of its spectrum. In particular such a correlation exists between the emission intensity of CO and its concentration. Use of this fact is then made to follow the rate of formation of carbon monoxide in methane–oxygen mixtures flowing through a discharge. The mechanism of formation of the various emitters either by means of a chemical reaction or by electron impact on molecules or radicals is discussed. It is concluded that to account for the rate of formation of CO, at least in the early stages of the presence of the gases in the discharge, before the steady state concentrations of atoms, radicals, and molecules have been approached, most of the energy of the electrons is used in breaking chemical bonds. The electric Held values needed to impart the necessary amount of energy to the electrons are of the same magnitude as those measured in this laboratory (~60 V cm−1).

scholarly journals Stochasticity in multi-phosphorylation and quasi steady state approximation in stochastic simulation

2018 ◽  
Author(s):  
S. Das ◽  
D. Barik
Keyword(s):  
Steady State ◽  
Stochastic Simulation ◽  
Chemical Reactions ◽  
Quasi Steady State ◽  
Chemical Noise ◽  
State Approximation ◽  
Steady State Approximation ◽  
Qualitative Nature ◽  
Multistep Reactions ◽  
Simulation Scheme

AbstractQuantitative and qualitative nature of chemical noise propagation in a network of chemical reactions depend crucially on the topology of reaction networks. Multisite reversible phosphorylation-dephosphorylation of target proteins is one such recurrently found topology in various cellular networks regulating key functions in living cells. Here we analytically calculated the stochasticity in multistep reversible chemical reactions by determining variance of phosphorylated species at the steady state using linear noise approximation. We investigated the dependence of variance on the rate parameters in the reaction chain and the number of phosphorylation sites on the species. Assuming a quasi steady state approximation on the multistep reactions, originating from the disparity in time scales in the network, we propose a simulation scheme for coupled chemical reactions to improve the computational efficiency of stochastic simulation of the network. We performed case studies on signal transduction cascade and positive feedback loop with bistability to show the accuracy and efficiency of the method.

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