Study of C2H5O2 using modulated photolysis: ultra-violet spectrum and self-reaction kinetics in the temperature range 233-363 K

1997 ◽  
Vol 94 ◽  
pp. 484-502
Author(s):  
S Fauvet ◽  
JP Ganne ◽  
J Brion ◽  
D Daumont ◽  
J Malicet ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
Ultra Violet ◽  
Temperature Range

scholarly journals Mechanism of reaction of silica and carbon for producing silicon carbide

2019 ◽  
Vol 45 ◽  
pp. 146867831989141
Author(s):  
Bahador Abolpour ◽  
Rahim Shamsoddini
Keyword(s):  
Experimental Data ◽  
Silicon Carbide ◽  
Reaction Kinetics ◽  
Direct Effect ◽  
Solid Reaction ◽  
Carbon Reduction ◽  
Temperature Range ◽  
Carbon Particles ◽  
Mechanism Of Reaction ◽  
Kinetics Of

The reaction kinetics of carbon reduction of silica were investigated using thermodynamic concepts and by fitting to relevant models the experimental data obtained for this reduction using a thermogravimetric unit in the temperature range of 1566 to 1933 K. The results show that the only way to produce SiC in this reduction is the reaction of Si, SiO, or SiO2 at the surface or by diffusion of SiO inside the carbon particles while CO and CO2 have no direct effect on the process. The controlling step of this reduction at temperatures lower than 1750 K is the chemical gas–solid or solid–solid reaction at the surface of the carbon particles, while at higher temperatures, the rate of SiO diffusing inside the carbon particles controls the rate of this reduction.

The reactions of oxygen at dark and irradiated zinc oxide surfaces

1960 ◽  
Vol 255 (1280) ◽  
pp. 124-144 ◽  
Keyword(s):  
Zinc Oxide ◽  
Previous History ◽  
Ultra Violet ◽  
Normal Behaviour ◽  
Adsorption And Desorption ◽  
Kinetics Of Adsorption ◽  
Temperature Range ◽  
Interstitial Zinc ◽  
Chemisorbed Oxygen ◽  
Type Semiconductor

Studies of the kinetics of adsorption of oxygen on zinc oxide over the temperature range from 25 to 390°C have provided evidence for two distinct types of chemisorption, one prevalent below 200 and the other above 300°C. This pattern of activity has been confirmed by measurements of desorption rates over the same temperature range. The mode of preparation and pretreatment of the oxide exert a strong influence on the adsorption behaviour, and these differences are accentuated when the processes of adsorption and desorption are studied in the presence of irradiation in the ultra-violet and visible. Photodesorption of oxygen is confirmed to be the normal behaviour for zinc oxide, but photo-adsorption has been observed under conditions of high excess zinc concentration. The photo-effects are especially marked below 300°C. The adsorption studies have been followed up by experiments on the rate of the intermolecular oxygen reaction 18 O 2 + 16 O 2 ⇌2 18 O 16 O, and on the influence of irradiation on this catalysis. It is evident that irradiation stimulates both adsorption and desorption, but the balance between them depends on the previous history of the specimen. The experiments with heavy oxygen have also included a brief study of oxygen exchange with zinc oxide at 400 to 500°C. The results as a whole are discussed in terms of the model of zinc oxide as an n -type semiconductor with interstitial zinc, and oxygen chemisorbed as O¯ and O 2¯ , respectively, are held to be mainly responsible for the phenomena observed. The relationship with conductivity studies is emphasized and the depletive chemisorption of oxygen, forming a boundary layer, is discussed in some detail. The depletion of electrons is not exhaustive for normal specimens of zinc oxide, and the treatment of this case leads to an expression consistent with the observed kinetics. Several possible mechanisms for photo-adsorption are put forward, and the association with high donor concentrations is discussed. Interstitial zinc diffusing under the influence of the electric field of chemisorbed oxygen is considered to play an important role in specimens heated above 300°C.

scholarly journals A combined high-temperature experimental and theoretical kinetic study of the reaction of dimethyl carbonate with OH radicals

2017 ◽  
Vol 19 (10) ◽  
pp. 7147-7157 ◽  
Author(s):  
Fethi Khaled ◽  
Binod Raj Giri ◽  
Milán Szőri ◽  
Tam V.-T. Mai ◽  
Lam K. Huynh ◽  
...  
Keyword(s):  
High Temperature ◽  
Shock Waves ◽  
Kinetic Study ◽  
Reaction Kinetics ◽  
Dimethyl Carbonate ◽  
Oh Radicals ◽  
Temperature Range ◽  
Reflected Shock ◽  
Kinetics Of

The reaction kinetics of dimethyl carbonate (DMC) and OH radicals were investigated behind reflected shock waves over the temperature range of 872–1295 K and at pressures near 1.5 atm.

Interface Reaction Kinetics for Permalloy-Tantalum Thin Film Couples

1994 ◽  
Vol 343 ◽  
Author(s):  
A.J. Kellock ◽  
J.E.E. Baglin ◽  
K.R. Coffey ◽  
J.K. Howard ◽  
M.A. Parker ◽  
...  
Keyword(s):  
Thin Film ◽  
Grain Boundaries ◽  
Reaction Kinetics ◽  
Interface Reaction ◽  
Nucleation And Growth ◽  
Fast Diffusion ◽  
Temperature Range

ABSTRACTThermal interdiffusion mechanisms and kinetics have been studied for Ta-Permalloy (Ni80Fe20), Ta-Ni and Ta-Fe thin film couples, in the temperature range 300°C - 600°C. Interaction modes identified for the Ta-NiFe system include: fast diffusion of Ta into grain boundaries of NiFe, and nucleation and growth of Ni3Ta, with consequent depletion of Ni in the remaining NiFe, and eventual segregation of Fe.

Photoluminescence from Gd-implanted AlN and GaN Epilayers

2006 ◽  
Vol 955 ◽  
Author(s):  
John M Zavada ◽  
Neeraj Nepal ◽  
J. Lin ◽  
K. H. Kim ◽  
H. X. Jiang ◽  
...  
Keyword(s):  
Thin Films ◽  
Emission Intensity ◽  
Emission Band ◽  
Ultra Violet ◽  
Sample Temperature ◽  
Temperature Range ◽  
Ti:Sapphire Laser ◽  
Uv Emission ◽  
Pl Emission

ABSTRACTGaN and AlN thin films were implanted with gadolinium (Gd)atoms and characterized using deep ultra-violet (UV) photoluminescence(PL). The Gd-implanted samples were annealed at temperatures up to 1178K in a flowing N2 gas to facilitate recovery of implantation-related damage. Using the output at 195 nm from a quadrupled Ti:sapphire laser, narrow PL emission was observed at 318 nm from the Gd- implanted AlN thin films. This emission is characteristic of the lowest energy 4f transition of the trivalent Gd ion. A boarder emission band, also centered at 318 nm, was observed under excitation at 266 nm. No PL emission was observed from the Gd-implanted GaN thin films at either the bandedge or due to a 4f transition. The dependence of the UV emission on AlN sample temperature was systematically studied. The peak PL emission intensity decreased by less that a factor of 3 over the temperature range of 10 K to 300 K. Decay transients of the UV emission were measured indicating that the lifetime of this emission is very fast.

Study of ClCH2CH2O2 using modulated photolysis: Ultra-violet spectrum and self-reaction kinetics

2003 ◽  
Vol 5 (12) ◽  
pp. 2573 ◽  
Author(s):  
A. Chakir ◽  
J. Brion ◽  
J. P. Ganne ◽  
D. Daumont
Keyword(s):  
Reaction Kinetics ◽  
Ultra Violet
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