The Kinetics of Low Pressure Rapid Thermal Oxidation of Silicon

1989 ◽  
Vol 146 ◽  
Author(s):  
Stephan E Lassig ◽  
John L
Keyword(s):  
Activation Energy ◽  
Thermal Oxidation ◽  
Rate Constant ◽  
Linear Dependence ◽  
Oxidation Kinetics ◽  
Parabolic Rate Constant ◽  
Parabolic Model ◽  
Parabolic Rate ◽  
Kinetics Of ◽  
Short Times

ABSTRACTA study of the oxidation kinetics of lightly doped (100) silicon in dry oxygen has been carried out at different pressures (0.03 atm. to 1.0 atm.) and temperatures (900ºC to 1200ºC) for short times (< 500 seconds). The data can be fit equally well to the parabolic model as it can to the linearparabolic or parallel oxidation models. The activation energy derived from analysis of the parabolic rate constant is 0.94 eVand is the same at 1.0 and 0.1 atmosphere dry O2. It was also found that the parabolic rate constant displayed a linear dependence on the O2 pressure.

Effect of Tackifier on Thermal Oxidation Kinetics and Effective Storage Time of Raw Natural Rubber

2014 ◽  
Vol 898 ◽  
pp. 102-106
Author(s):  
Bei Long Zhang ◽  
Hong Hai Huang ◽  
Wei Yong Deng ◽  
Yong Zhou Wang ◽  
Li Ding ◽  
...  
Keyword(s):  
Activation Energy ◽  
Natural Rubber ◽  
Thermal Oxidation ◽  
Oxidation Kinetics ◽  
Storage Time ◽  
Hydrazine Sulfate ◽  
Accelerated Storage ◽  
Thermal Oxidation Kinetics ◽  
Storage Times ◽  
Kinetics Of

The thermal oxidation kinetics of natural rubber containing hydrazine dihydrochloride or hydrazine sulfate used as tackifier were studied, and the effective storage time of natural rubber containing tackifier was predicted with a method of heat accelerated storage aging. The results show that the thermal oxidation activation energy of natural rubber containing hydrazine dihydrochloride is 105.6kJ/ mol, being a little higher than that (104.7 kJ/ mol) of the control. The thermal oxidation activation energy of natural rubber containing hydrazine sulfate is 103.1kJ/ mol, being a little lower than that of the control. The effective storage time of natural rubber containing hydrazine dihydrochloride is 13.4 years at 30°C,27.0years at 25°C, and 55.9years at 20°C. The effective storage time of natural rubber containing hydrazine sulfate is 11.6years at 30°C,23.0 at 25°C, and 46.8years at 20°C.The effective storage times of natural rubber containing two tackifiers hydrazine dihydrochloride or hydrazine sulfate are higher than that of the control at the same condition.

On the Defect Structure and Transport Properties of NiS2

2012 ◽  
Vol 323-325 ◽  
pp. 315-320
Author(s):  
Zbigniew Grzesik ◽  
A. Poczekajło ◽  
S. Mrowec
Keyword(s):  
Transport Properties ◽  
Rate Constant ◽  
Defect Structure ◽  
Parabolic Rate Constant ◽  
Cation Sublattice ◽  
Cation Vacancies ◽  
Parabolic Rate ◽  
Pressure Independent ◽  
Kinetics Of

Because of considerable experimental difficulties, the defect structure of NiS2 has not been elucidated so far. The first step in these investigations was to explain which sublattice of this compound is predominantly disordered. In order to solve this problem, the mechanism of sulphidation of NiS to NiS2 has been studied using marker technique. These experiments have been carried out at temperatures 823-923 K in sulphur vapors under pressure 103 105 Pa. It has been found that the predominant defects in NiS2 occur in cation sublattice. The problem then arised whether these defects are cation vacancies or interstitial cations. This phenomenon could have been explained in studying the kinetics of NiS sulphidation as a function of sulphur activity. It has been found that the parabolic rate constant of this reaction increases with sulphur activity, strongly suggesting that cation vacancies, and not cation interstitials, are the prevailing defects. If, namely, interstitial cations would prevail, the sulphidation rate would be virtually pressure independent.

Oxidation of Nickel(II) and Manganese(II) by Peroxodisulfate in Aqueous Solution in the Presence of Molybdate. Crystal Structure of the (NH4)6[NiMo9O32].6H2O Product

1992 ◽  
Vol 45 (12) ◽  
pp. 1943 ◽  
Author(s):  
SJ Dunne ◽  
RC Burns ◽  
GA Lawrance
Keyword(s):  
Rate Constant ◽  
Linear Dependence ◽  
Ph Dependence ◽  
Order Rate Constant ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Order ◽  
Oxidant Concentration ◽  
Ph Range ◽  
Kinetics Of

Oxidation of Ni2+,aq, by S2O82- to nickel(IV) in the presence of molybdate ion, as in the analogous manganese system, involves the formation of the soluble heteropolymolybdate anion [MMogO32]2- (M = Ni, Mn ). The nickel(IV) product crystallized as (NH4)6 [NiMogO32].6H2O from the reaction mixture in the rhombohedra1 space group R3, a 15.922(1), c 12.406(1) � ; the structure was determined by X-ray diffraction methods, and refined to a residual of 0.025 for 1741 independent 'observed' reflections. The kinetics of the oxidation were examined at 80 C over the pH range 3.0-5.2; a linear dependence on [S2O82-] and a non-linear dependence on l/[H+] were observed. The influence of variation of the Ni/Mo ratio between 1:10 and 1:25 on the observed rate constant was very small at pH 4.5, a result supporting the view that the precursor exists as the known [NiMo6O24H6]4- or a close analogue in solution. The pH dependence of the observed rate constant at a fixed oxidant concentration (0.025 mol dm-3) fits dequately to the expression kobs = kH [H+]/(Ka+[H+]) where kH = 0.0013 dm3 mol-1 s-1 and Ka = 4-0x10-5. The first-order dependence on peroxodisulfate subsequently yields a second-order rate constant of 0.042 dm3 mol-1 s-1. Under analogous conditions, oxidation of manganese(II) occurs eightfold more slowly than oxidation of nickel(II), whereas oxidation of manganese(II) by peroxomonosulfuric acid is 16-fold faster than oxidation by peroxodisulfate under similar conditions.

scholarly journals Analysis of the Kinetics of Swimming Pool Water Reaction in Analytical Device Reproducing Its Circulation on a Small Scale

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4820 ◽  
Author(s):  
Wojciech Kaczmarek ◽  
Jarosław Panasiuk ◽  
Szymon Borys ◽  
Aneta Pobudkowska ◽  
Mikołaj Majsterek
Keyword(s):  
Activation Energy ◽  
Water Quality ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Small Scale ◽  
Pool Water ◽  
Swimming Pool Water ◽  
Kinetics Of ◽  
Analytical Device

The most common cause of diseases in swimming pools is the lack of sanitary control of water quality; water may contain microbiological and chemical contaminants. Among the people most at risk of infection are children, pregnant women, and immunocompromised people. The origin of the problem is a need to develop a system that can predict the formation of chlorine water disinfection by-products, such as trihalomethanes (THMs). THMs are volatile organic compounds from the group of alkyl halides, carcinogenic, mutagenic, teratogenic, and bioaccumulating. Long-term exposure, even to low concentrations of THM in water and air, may result in damage to the liver, kidneys, thyroid gland, or nervous system. This article focuses on analysis of the kinetics of swimming pool water reaction in analytical device reproducing its circulation on a small scale. The designed and constructed analytical device is based on the SIMATIC S7-1200 PLC driver of SIEMENS Company. The HMI KPT panel of SIEMENS Company enables monitoring the process and control individual elements of device. Value of the reaction rate constant of free chlorine decomposition gives us qualitative information about water quality, it is also strictly connected to the kinetics of the reaction. Based on the experiment results, the value of reaction rate constant was determined as a linear change of the natural logarithm of free chlorine concentration over time. The experimental value of activation energy based on the directional coefficient is equal to 76.0 [kJ×mol−1]. These results indicate that changing water temperature does not cause any changes in the reaction rate, while it still affects the value of the reaction rate constant. Using the analytical device, it is possible to constantly monitor the values of reaction rate constant and activation energy, which can be used to develop a new way to assess pool water quality.

Thermal oxidation reaction process and oxidation kinetics of abietic acid

RSC Advances ◽  
2015 ◽  
Vol 5 (22) ◽  
pp. 17123-17130 ◽  
Author(s):  
Fan Ren ◽  
Yan-Fei Zheng ◽  
Xiong-Min Liu ◽  
Qiong-Qiong Yang ◽  
Qiang Zhang ◽  
...  
Keyword(s):  
Kinetic Study ◽  
Thermal Oxidation ◽  
Oxidation Kinetics ◽  
Oxidation Reaction ◽  
Abietic Acid ◽  
Reaction Process ◽  
Basic Data ◽  
Kinetics Of

A kinetic study on the oxidation of abietic acid, providing new basic data.

Oxidation kinetics of Si and SiGe by dry rapid thermal oxidation, in-situ steam generation oxidation and dry furnace oxidation

2017 ◽  
Vol 121 (24) ◽  
pp. 245308 ◽  
Author(s):  
Fabien Rozé ◽  
Olivier Gourhant ◽  
Elisabeth Blanquet ◽  
François Bertin ◽  
Marc Juhel ◽  
...  
Keyword(s):  
Thermal Oxidation ◽  
Oxidation Kinetics ◽  
Steam Generation ◽  
Rapid Thermal Oxidation ◽  
Kinetics Of

scholarly journals The combination of carbon monoxide–haem with apoperoxidase

1969 ◽  
Vol 114 (4) ◽  
pp. 719-724 ◽  
Author(s):  
Charles Phelps ◽  
Eraldo Antonini
Keyword(s):  
Activation Energy ◽  
Carbon Monoxide ◽  
Rate Constant ◽  
Binding Sites ◽  
Order Process ◽  
First Order ◽  
Effects Of Ph ◽  
Kinetics Of

1. Static titrations reveal an exact stoicheiometry between various haem derivatives and apoperoxidase prepared from one isoenzyme of the horseradish enzyme. 2. Carbon monoxide–protohaem reacts rapidly with apoperoxidase and the kinetics can be accounted for by a mechanism already applied to the reaction of carbon monoxide–haem derivatives with apomyoglobin and apohaemoglobin. 3. According to this mechanism a complex is formed first whose combination and dissociation velocity constants are 5×108m−1sec.−1 and 103sec.−1 at pH9·1 and 20°. The complex is converted into carbon monoxide–haemoprotein in a first-order process with a rate constant of 235sec.−1 for peroxidase and 364sec.−1 for myoglobin at pH9·1 and 20°. 4. The effects of pH and temperature were examined. The activation energy for the process of complex-isomerization is about 13kcal./mole. 5. The similarity in the kinetics of the reactions of carbon monoxide–haem with apoperoxidase and with apomyoglobin suggests structural similarities at the haem-binding sites of the two proteins.

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