The Kinetics of Damage Removal Metastable Carrier Concentration Relaxation and Secondary Defect Evolution During RTA

1988 ◽  
Vol 100 ◽  
Author(s):  
Xu Ii ◽  
Tsien Peihsin ◽  
Li Zhljan
Keyword(s):  
Critical Temperature ◽  
Carrier Concentration ◽  
Annealing Temperature ◽  
Activation Energies ◽  
Time Duration ◽  
Defect Evolution ◽  
Secondary Defect ◽  
Kinetics Of

ABSTRACTThe kinetics of damage removal, metastable carrier concentration relaxation and secondary defect evolution in As+-implanted and rapidly annealed silicon was studied m detail. It was found that these processes are characterized by different activation energies. There is a critical temperature Tc for RTA. Only when the annealing temperature is higher than Tc, with suitable time duration can the RTA advantages be fully exloited.

Kinetics of esterification of monoisopropylphenols with phosphoryl trichloride

1989 ◽  
Vol 54 (5) ◽  
pp. 1311-1317
Author(s):  
Miroslav Magura ◽  
Ján Vojtko ◽  
Ján Ilavský
Keyword(s):  
Liquid Phase ◽  
Rate Constants ◽  
Reaction Rates ◽  
Activation Energies ◽  
The Individual ◽  
Kinetics Of

The kinetics of liquid-phase isothermal esterification of POCl3 with 2-isopropylphenol and 4-isopropylphenol have been studied within the temperature intervals of 110 to 130 and 90 to 110 °C, respectively. The rate constants and activation energies of the individual steps of this three-step reaction have been calculated from the values measured. The reaction rates of the two isomers markedly differ: at 110 °C 4-isopropylphenol reacts faster by the factors of about 7 and 20 for k1 and k3, respectively. This finding can be utilized in preparation of mixed triaryl phosphates, since the alkylation mixture after reaction of phenol with propene contains an excess of 2-isopropylphenol over 4-isopropylphenol.

scholarly journals Physical properties and water absorption kinetics of three varieties of Mucuna beans

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ajibola B. Oyedeji ◽  
Olajide P. Sobukola ◽  
Ezekiel Green ◽  
Oluwafemi A. Adebo
Keyword(s):  
Physical Properties ◽  
Water Absorption ◽  
Rate Constant ◽  
Geometric Mean ◽  
Seed Mass ◽  
Activation Energies ◽  
Mucuna Pruriens ◽  
Absorption Kinetics ◽  
Kinetics Of ◽  
Soaking Temperature

AbstractThe physical properties and water absorption kinetics of three varieties of Mucuna beans (Mucuna pruriens, Mucuna rajada and Mucuna veracruz) were determined in this study. Physical properties including length, width, thickness, geometric mean diameter, sphericity, porosity, bulk density, area, volume and one thousand seed mass were calculated while hydration kinetics was studied by soaking Mucuna beans in water at 30 °C, 40 °C and 50 °C and measuring water uptake at 9 h interval. Peleg’s equation was used to model the hydration characteristics and Arrhenius equation was used to describe the effect of temperature on Peleg’s rate constant k1 and to obtain the activation energies for soaking. Significant variations were observed in almost all the physical properties of the different varieties, however, there were no significant differences (p < 0.05) in their thicknesses and bulk densities. The effectiveness of fit of Peleg’s model (R2) increased with increase in soaking temperature. Peleg’s rate constant k1 decreased with increase in soaking temperature while k2 increased with temperature increase. Activation energies of Mucuna pruriens, Mucuna rajada and Mucuna veracruz were 1613.24 kJ/mol, 747.95 kJ/mol and 2743.64 kJ/mol, respectively. This study provides useful information about the properties of three varieties of Mucuna beans that could be of importance to processors and engineers for process design and optimization.

The kinetics of hydration of tricalcium silicate

1970 ◽  
Vol 48 (21) ◽  
pp. 3291-3299 ◽  
Author(s):  
K. G. McCurdy ◽  
B. P. Erno
Keyword(s):  
Reaction Mechanism ◽  
Intermediate Product ◽  
Activation Energies ◽  
Tricalcium Silicate ◽  
Rate Data ◽  
Large Excess ◽  
First Order ◽  
Kinetics Of ◽  
Subsequent Decomposition

An investigation has been made of the kinetics of hydration of tricalcium silicate at several temperatures in a large excess of water in the presence of various added ions. The rate data have been interpreted by a reaction mechanism which involves: (a) the first order hydration of tricalcium silicate to form an intermediate product, 1.5CaO•SiO2, which can react by two pathways, (b) the direct first order decomposition of intermediate, 1.5CaO•SiO2, to form lime and silica or (b′) complexing of intermediate with silica and subsequent decomposition to form lime and silica. This reaction mechanism predicts the rate of production of base during the hydration. The effect of various added ions is interpreted in terms of the proposed mechanism.Rate constants and activation energies for the various steps in the proposed mechanism are reported.

Reduction Kinetics of Mill Scale Briquettes by Using A3 Fine Coal as a Reductant

2021 ◽  
Vol 21 (4) ◽  
pp. 2563-2567
Author(s):  
Nguyen Hoang Viet ◽  
Pham Ngoc Dieu Quynh ◽  
Nguyen Thi Hoang Oanh
Keyword(s):  
Reaction Rate ◽  
Reduction Process ◽  
Reduction Reaction ◽  
Reaction Rate Constant ◽  
Reduction Degree ◽  
Furnace Temperature ◽  
Time Duration ◽  
Mill Scale ◽  
Fine Coal ◽  
Kinetics Of

In this work, a mixture of mill scale with 5 wt% molasses as binder was pressed under pressure of 200 MPa to prepare briquettes. The reduction process was performed at the temperature of 1000, 1050, 1100, 1150 and 1200 °C in the bed of A3 fine coal as the reductant. The degree of reduction was evaluated at time duration of 15, 30, 45, 60, 90 and 150 minutes, after the furnace temperature reached the predetermined reduction temperature. The highest reduction degree is 94.7% at the reduction process temperature of 1200 °C. Reaction rate constant (k) increased from 4.63×10-4 to 5.03×10-3 min-1 when the temperature increased from 1000 to 1200 °C. The apparent activation energy of the reduction reaction (Ea) is about 95.6 kJ/mole.

scholarly journals Influence of Annealing Temperature on the Crystallization Kinetics of Fe82Si8B10 Amorphous Ribbon

2020 ◽  
Vol 11 (1) ◽  
pp. 107-112
Author(s):  
A Said Sikder ◽  
SD Nath ◽  
SS Sikder
Keyword(s):  
Crystallization Kinetics ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Amorphous Ribbon ◽  
Primary Crystallization ◽  
Soft Magnetic Materials ◽  
Power Transformers ◽  
Soft Magnetic ◽  
Potential Applications ◽  
Kinetics Of

Amorphous soft magnetic materials have significant potential applications in specialist power transformers and in inductive devices. With the composition of Fe82Si8B10, 82% of the transition metals Fe and about 18% of metalloid or glass-former elements like B and Si are strongly magnetic at room temperature and offer dynamic opportunities for engineering applications. The crystallization kinetics has been studied by differential thermal analysis (DTA). The sample was annealed in a controlled way in the temperature range of 350-450°C at constant annealing time one hour. The kinetics of primary crystallization α-Fe(Si) phase and secondary crystallization Fe2B phase was studied as affected due to temperature. The sample annealed at 350oC temperature is almost unchanged which is still lower than that of primary crystallization temperature but the same condition when sample annealed at 450°C completely shows that the primary crystallization α-Fe(Si) phase has vanished and crystallization event took place to a good extent. Journal of Engineering Science 11(1), 2020, 107-112

scholarly journals Desorption and re-adsorption of PAHS on aircraft soot surface

2020 ◽  
Vol 42 (4) ◽  
Author(s):  
Nguyen Mai Lan
Keyword(s):  
High Performance ◽  
Flow Reactor ◽  
Activation Energies ◽  
Binding Energies ◽  
Desorption Kinetics ◽  
Chemical Transformations ◽  
Polycyclic Aromatic ◽  
Kinetics Of Degradation ◽  
Kinetics Of ◽  
Pyrex Tube

Polycyclic Aromatic Hydrocarbons (PAHs) in aircraft soot are capable to distribute in the gas phase and particulate phase in chemical transformations in the atmosphere. The desorption of PAHs from the soot surface is a preliminary step in the study of the reactivity of particulate PAHs. The desorption kinetics of PAHs are measured from soot samples to determine desorption rate constants for different PAHs as a function of temperature and the binding energies between PAHs and soot. The kinetics of degradation of particulate PAHs were studied in the flow reactor. The soot samples previously deposited on a Pyrex tube are introduced into the reactor along its axis and the concentrations of PAHs adsorbed on soot are determined by the High-Performance Liquid Chromatography (HPLC) as a function of the desorption time. The results show a correlation between the size of PAHs and the thermodynamics of desorption: with the PAHs have the same number of carbon atoms, their energies of desorption are very similar and increase with this number. The activation energies EA and the number of carbon atoms in PAHs have a linear correlation. It is consistent with the additivity of the laws Van der Waals. The similarity between the activation energies of desorption of PAHs and the corresponding sublimation enthalpies is consistent with the similarity between the graphitic structure of soot and the structure of PAHs.

Study of Donor Centres in n-InSb due to the Temperature Annealing

2005 ◽  
Vol 480-481 ◽  
pp. 197-200
Author(s):  
Y. Sayad ◽  
A. Nouiri
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Annealing Time ◽  
Annealing Temperature ◽  
Theoretical Study ◽  
Donor Concentration ◽  
Model Based ◽  
Proposed Model ◽  
Kinetics Of ◽  
Best Fit

An increasing of donor centres has been detected in n-InSb when it was submitted to anneal/quench with various annealing temperature (450 °C - 850 °C) and various annealing time (5 - 100 hours). A theoretical study of the kinetics of the conduction conversion of n-InSb at temperature annealing above 250 °C has been made. The present analysis indicates that the donor concentration increases with increasing of annealing time. In order to study this variation and to give a model for donor centres generated, a proposed model based on the simple kinetic is used to fit the variation of donor concentration as a function of annealing time. However, from the best fit of experimental data using the proposed model, the activation energy is determined.

Growth Kinetics of Interfacial Intermetallic Compound in Al(AA4343)/Steel(SUS316) Clad Strip

2020 ◽  
Vol 993 ◽  
pp. 447-456
Author(s):  
Xiao Jun Zhang ◽  
Kun Yuan Gao ◽  
Xiu Hua Hu ◽  
Yu Sheng Ding ◽  
Guo Zhan Wang ◽  
...  
Keyword(s):  
Growth Kinetics ◽  
Annealing Temperature ◽  
Optical Microscope ◽  
Alloy Layer ◽  
Kinetics Analysis ◽  
Growth Constant ◽  
Transmission Electron ◽  
Dispersive System ◽  
The Relationship ◽  
Kinetics Of

The composition and microstructure of intermetallic compounds (IMC) at the interface of aluminum(AA4343)-stainless steel(SUS316) were studied upon annealing at 550°C for 1h to 20h and at 610°C for 15min to 10h by means of optical microscope(OM) , scanning electron microscope (SEM) with energy dispersive system(EDS) and transmission Electron Microscopy (TEM). The results showed that the IMC was of 4.3μm to 36.1μm thick during heat treatment at 550°C for 1h to 20h, and the IMC contained Al-Fe-Si-Cr-Ni-Mo and Al-Fe-Si -Ni. During annealing at 610°C for 15min to 5h, the thickness of IMC was 31.2 μm to 208 μm, and the IMC were mainly of η-Fe2Al5 and τ10- Al4Fe1.7Si at 550°C for 10h. As the annealing time extended to 10h, natural delamination occurred at the interface between the aluminum alloy layer and IMC layer. The growth kinetics analysis showed that the relationship between the thickness of IMC “X” and time “t” followed the relational equation X=(kt)n. For AA4343(solid) - SUS316(solid), n was 1/2, and the growth constant k = 1.9×10-13m2/s at annealing temperature of 550 °C. When the temperature was 610°C, AA4343 - SUS316 was a liquid-solid contact reaction, n was 1, the growth constant k=1.45×10-8m/s.

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