Hydrogen Segregation at the Al/Si Interface Studied Using a Nuclear Resonant Reaction

1989 ◽  
Vol 163 ◽  
Author(s):  
Joyce C. Liu ◽  
A.D. Marwick ◽  
F.K. Legoues
Keyword(s):  
Binding Energy ◽  
Annealing Time ◽  
Release Rates ◽  
Depth Profiles ◽  
First Order ◽  
Thermally Activated ◽  
Isothermal Anneal ◽  
Hydrogen Segregation ◽  
Resonant Reaction ◽  
Trapping Process

AbstractHydrogen segregation at the interface between an epitaxial Al film and a Si (111) substrate is studied using the 1H(15N, αγ)12C nuclear resonant reaction. Hydrogen depth profiles show that H atoms diffuse through the 1600 Å thick Al layer during 500 eV H implantation and are trapped at the Al/Si interface. The total amount of interface H is about 2 × 1015 /cm2 after a 1.4 × 1018 H/cm2 implantation, and the H atoms are narrowly distributed in the direction normal to the interface. During an isothermal anneal at 360 K, the amount of interface H decreases exponentially with annealing time; and during ramp annealing from 110 to 500 K, an abrupt release of the interface H is observed at temperature around 380 K. The release rates in both cases are controlled by a first order thermally activated de-trapping process with a binding energy of 0.86 eV/atom.

scholarly journals Kinetics of K release from soils of Brazilian coffee regions: effect of organic acids

2008 ◽  
Vol 32 (2) ◽  
pp. 533-540 ◽  
Author(s):  
Vladimir Antônio Silva ◽  
Giuliano Marchi ◽  
Luiz Roberto Guimarães Guilherme ◽  
José Maria de Lima ◽  
Francisco Dias Nogueira ◽  
...  
Keyword(s):  
Release Kinetics ◽  
Kinetic Studies ◽  
Release Rates ◽  
First Order ◽  
Potassium Release ◽  
Minas Gerais State ◽  
Soil Clay ◽  
Extractant Solution ◽  
Kinetics Of ◽  
K Release

Kinetic studies on soil potassium release can contribute to a better understanding of K availability to plants. This study was conducted to evaluate K release rates from the whole soil, clay, silt, and sand fractions of B-horizon samples of a basalt-derived Oxisol and a sienite-derived Ultisol, both representative soils from coffee regions of Minas Gerais State, Brazil. Potassium was extracted from each fraction after eight different shaking time periods (0-665 h) with either 0.001 mol L-1 citrate or oxalate at a 1:10 solid:solution ratio. First-order, Elovich, zero-order, and parabolic diffusion equations were used to parameterize the time dependence of K release. For the Oxisol, the first-order equation fitted best to the experimental data of K release, with similar rates for all fractions and independent of the presence of citrate or oxalate in the extractant solution. For all studied Ultisol fractions, in which K release rates increased when extractions were performed with citrate solution, the Elovich model described K release kinetics most adequately. The highest potassium release rate of the Ultisol silt fraction was probably due to the transference of "non-exchangeable" K to the extractant solution, whereas in the Oxisol exchangeable potassium represented the main K source in all studied fractions.

scholarly journals Oxidative Degradation of Amoxicillin in Aqueous Solution by Thermally Activated Persulfate

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Juanjuan Zhao ◽  
Yujiao Sun ◽  
Fachao Wu ◽  
Minjian Shi ◽  
Xurui Liu
Keyword(s):  
Aqueous Solution ◽  
Reaction Temperature ◽  
Oxidative Degradation ◽  
Water Remediation ◽  
Order Kinetic ◽  
Production Chain ◽  
First Order ◽  
Thermally Activated ◽  
Pseudo First Order ◽  
Activated Persulfate

Antibiotic residues and antibiotic resistance genes (ARGs) pose a great threat to public health and food security via the horizontal transfer in the food production chain. Oxidative degradation of amoxicillin (AMO) in aqueous solution by thermally activated persulfate (TAP) was investigated. The AMO degradation followed a pseudo-first-order kinetic model at all tested conditions. The pseudo-first-order rate constants of AMO degradation well-fitted the Arrhenius equation when the reaction temperature ranged from 35°C to 60°C, with the apparent activate energy of 126.9 kJ·mol−1. High reaction temperature, high initial persulfate concentration, low pH, high Cl− concentration, and humic acid (HA) concentration increased the AMO degradation efficiency. The EPR test demonstrated that both ·OH and SO4·− were generated in the TAP system, and the radical scavenging test identified that the predominant reactive radical species were SO4·− in aqueous solution without adjusting the solution pH. In groundwater and drinking water, AMO degradation suggested that TAP could be a reliable technology for water remediation contaminated by AMO in practice.

EFFECT OF SLOW HEATING AND COOLING ON THE INTERDIFFUSION OF THIN FILMS

2007 ◽  
Vol 14 (04) ◽  
pp. 703-707 ◽  
Author(s):  
H. D. JOUBERT ◽  
J. J. TERBLANS ◽  
H. C. SWART
Keyword(s):  
Thin Films ◽  
Annealing Time ◽  
Slow Heating ◽  
Heating Period ◽  
Depth Profiles ◽  
Heating And Cooling ◽  
Diffusion Parameters ◽  
Exact Moment ◽  
The Moment ◽  
Heating Profiles

Interdiffusion parameters are often extracted from depth profiles of the interface of annealed thin films by measuring the annealing time of the sample as well as the distance over which interdiffusion took place. The annealing time is usually taken as the time from the moment the sample enters the oven to the exact moment the sample is removed from the oven. However, diffusion does not start and stop at these points, as the temperature of the sample does not change instantaneously. Any calculation performed with the instantaneous and therefore erroneous time will result in incorrect diffusion parameters extracted from the depth profiles. The influence of the extended heating period is studied by solving Fick's second law numerically and employing three distinct heating profiles in the calculations, namely instantaneous, actual, and linear. The results indicate a clear difference between the first two calculated depth profiles. Using these calculations and some experimental results, a method that employs linear heating and cooling of a sample is proposed for studying the interdiffusion of fast diffusing elements (with low activation energies).

The interaction of normal and metastable helium atoms

1952 ◽  
Vol 213 (1114) ◽  
pp. 327-349 ◽  
Keyword(s):  
Binding Energy ◽  
Dipole Interaction ◽  
Wave Functions ◽  
Positive Maximum ◽  
Metastable Helium ◽  
Helium Atoms ◽  
First Order ◽  
Singlet States ◽  
Energy Of Interaction ◽  
Analytic Wave

The energy of interaction of a normal helium atom and one excited to the first triplet or singlet metastable state is calculated over a range of nuclear separations from a 0 to 12 a 0 . The Heitler-London method is followed, with inclusion of all non-orthogonality integrals, and using analytic wave functions. Because of identity of the nuclei, g and u states of interaction occur, the energy of the u state having a minimum at about 2·1 a 0 , and a positive maximum of 0·29 and 0·26 eV (for triplet and singlet states respectively) at about 4 a 0 ; the g state is entirely repulsive. Comparison is made with experimental evidence for the binding energy of normal and metastable (triplet) atoms. An estimate is made of the second-order dipole-dipole interaction for large separations, and it seems certain that the first-order interaction dominates at least to 12 a 0 . Methods of calculating the necessary integrals are discussed in an appendix.

Oxidative Degradation and Kinetics of Trichloroethylene by Thermally Activated Persulfate

2014 ◽  
Vol 675-677 ◽  
pp. 547-550
Author(s):  
Jun Jie Yue ◽  
Xiao Qiao Zhu ◽  
Yu Ting Wang ◽  
Yu Qin Zhang ◽  
Li Zhao ◽  
...  
Keyword(s):  
Oxidative Degradation ◽  
Chemical Oxidation ◽  
Molar Ratio ◽  
Pseudo First Order Reaction ◽  
In Situ Chemical Oxidation ◽  
First Order ◽  
Molar Ratios ◽  
Thermally Activated ◽  
Kinetics Of

In situ chemical oxidation with persulfate (PS) anion (S2O82-) is a viable technique for remediation of groundwater contaminants such as trichloroethylene (TCE). This laboratory study investigated the use of the oxidant sodium PS for the chemical oxidation of TCE at different conditions to determine the influence of temperature, pH, and the PS/TCE molar ratio. Experiments revealed that higher temperatures, lower pH, and higher PS/TCE molar ratios were to the benefit of TCE oxidation by PS. By investigating the reaction kinetics, the degradations of contaminant can be described by use of pseudo-first-order reaction. At the temperatures ranging from 25°C to 40°C, the activation energy for the degradation of TCE was determined to be 85.04 KJ/mol.

scholarly journals Donor binding energy and thermally activated persistent photoconductivity in high mobility (001) AlAs quantum wells

2007 ◽  
Vol 91 (14) ◽  
pp. 142120 ◽  
Author(s):  
S. Dasgupta ◽  
C. Knaak ◽  
J. Moser ◽  
M. Bichler ◽  
S. F. Roth ◽  
...  
Keyword(s):  
Binding Energy ◽  
Quantum Wells ◽  
High Mobility ◽  
Persistent Photoconductivity ◽  
Thermally Activated ◽  
Donor Binding Energy
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