scholarly journals MECHANISM OF HYDROCHEMICAL OXIDATION OF HEAZLEWOODITE IN NITRIC ACID

2020 ◽  
pp. 83-89
Author(s):  
Анна Игоревна Пичугина ◽  
Дарья Дмитриевна Гончар
Keyword(s):  
Activation Energy ◽  
Mathematical Model ◽  
Nitric Acid ◽  
Rate Constant ◽  
Effective Activation Energy ◽  
Dissolution Process ◽  
Effective Activation ◽  
Kinetic Characteristics ◽  
Dilute Solutions ◽  
Modes Of Interaction

В работе представлена математическая модель гидрохимического окисления хизлевудита в разбавленных растворах азотной кислоты. Дана физико-химическая интерпретация основных кинетических характеристик процесса растворения: константа скорости и эффективная энергия активации. Установлены режимы взаимодействия хизлевудита с азотной кислотой, выявлены вероятные лимитирующие стадии. По наблюдаемым кинетическим закономерностям при моделировании процесса, предложен механизм гидрохимического окисления хизлевудита. The paper presents a mathematical model of the hydrochemical oxidation of heazlewoodite in dilute solutions of nitric acid. A physicochemical interpretation of the main kinetic characteristics of the dissolution process is given: the rate constant and the effective activation energy. The modes of interaction of heazlewoodite with nitric acid have been established, and probable limiting stages have been identified. According to the observed kinetic regularities in modeling the process, a mechanism for the hydrochemical oxidation of heazlewoodite has been proposed.

MAGNETIC RESISTIVITY IN Bi2Sr2Ca(Cu1-xCox)2Od EPITAXIAL THIN FILMS

2007 ◽  
Vol 21 (01) ◽  
pp. 127-132
Author(s):  
T. R. YANG ◽  
G. ILONCA ◽  
V. TOMA ◽  
P. BALINT ◽  
M. BODEA
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
Activation Energy ◽  
Glass Transition ◽  
Effective Activation Energy ◽  
Epitaxial Thin Films ◽  
Effective Activation ◽  
High Quality ◽  
Plastic Deformations ◽  
Magnetic Resistivity

The scaling behavior of the effective activation energy of high-quality epitaxial c-oriented Bi 2 Sr 2 Ca ( Cu 1-x Co x)2 O d thin films with 0≤x ≤0.025 has been studied as a function of temperature and magnetic field. For all samples, the effective activation energy scales as U(T, μoH)=Uo(1-T/T c )mHn with exponent m=1.25±0.03, n=-1/2 and the field scaling 1/μoH and -UμoH for thick films and ultra thin films, respectively. The results are discussed taking into account of the influence of the Co substitution with a model in which U(T, H) arises from plastic deformations of the viscous flux liquid above the vortex-glass transition temperature.

Correlation between effective activation energy and pre-exponential factor for diffusion in bulk metallic glasses

1999 ◽  
Vol 14 (8) ◽  
pp. 3200-3203 ◽  
Author(s):  
S. K. Sharma ◽  
F. Faupel
Keyword(s):  
Activation Energy ◽  
Metallic Glasses ◽  
Effective Activation Energy ◽  
Bulk Metallic Glasses ◽  
Supercooled Liquid ◽  
The Novel ◽  
Effective Activation ◽  
Exponential Factor ◽  
Liquid States ◽  
Fitting Parameters

The values of effective activation energy (Q) and pre-exponential factor (D0) reported in the literature for diffusion in the novel bulk metallic glasses, both in the glassy and the deeply supercooled liquid regions, are found to follow the same correlation as reported earlier in conventional metallic glasses, namely D0 = A exp(Q/B), where A and B are fitting parameters with values A = 4.8 × 10−19 m2 s−1 and B = 0.056 eV atom−1. A possible explanation for the observed values of A and B is given by combining an activation energy and a free volume term. The interpretation favors a cooperative mechanism for diffusion in the glassy and deeply supercooled liquid states.

MAGNETORESISTIVITY PROPERTIES AND EFFECTIVE ACTIVATION ENERGY IN YBa2Cu3O7-ρ SUPERCONDUCTING THIN FILM

2006 ◽  
Vol 20 (29) ◽  
pp. 1847-1852
Author(s):  
ALI IHSAN DEMIREL ◽  
SALIM ORAK
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Activation Energy ◽  
Applied Field ◽  
Effective Activation Energy ◽  
Creep Process ◽  
Two Dimensional ◽  
Effective Activation ◽  
Exponential Behavior ◽  
Superconducting Thin Film

The resistive properties and activation energy of YBa 2 Cu 3 O 7-ρ ( YBCO ) superconducting materials change in magnetic field. It is explained that magnetoresistive behavior in terms of the presence of two-dimensional vortices being pinned effectively when they are perpendicular to the CuO 2 planes and an exponential behavior of the activation energy versus the applied field was obtained. The resulting activation energies ranging from 1 to 5 Tesla were attributed to inter-granular flux creep process.

Temperature Dependence of the Electrical Transport of Carbon Doped Gan

1996 ◽  
Vol 421 ◽  
Author(s):  
Wim Geerts ◽  
J.D. MacKenzie ◽  
C.R. Abernathy ◽  
S.J Pearton ◽  
Thomas Schmiedel
Keyword(s):  
Activation Energy ◽  
Charge Transport ◽  
Temperature Dependence ◽  
Electrical Transport ◽  
Effective Activation Energy ◽  
Impurity Band ◽  
Hall Voltage ◽  
Effective Activation ◽  
Carbon Doped ◽  
P Type

AbstractThe temperature dependence of the Hall voltage and resistivity of highly carbon doped GaN were measured. From the sign of the Hall voltage, the material appears to be p-type. Charge transport takes place in an impurity band and the valence band. The effective activation energy as estimated from the maximum in the temperature versus Hall voltage relation is 10–30 meV.

(Rapid) Thermal Nitridation of SiO2 films

1989 ◽  
Vol 146 ◽  
Author(s):  
J.B. Oude Elferink ◽  
F.H.P.M. Habraken ◽  
W.F. van der Weg
Keyword(s):  
Activation Energy ◽  
Silicon Dioxide ◽  
Effective Activation Energy ◽  
Effective Activation ◽  
Nitrogen Incorporation ◽  
Nitridation Process ◽  
Initial Stage ◽  
Thermal Nitridation ◽  
Silicon Nitridation

ABSTRACTIn this paper we report on the composition of thermally nitrided silicon dioxide films on silicon. Nitridation temperatures ranging from 950 to 1150ºC and nitridation times ranging from 10 to 240 s were used. The purpose of this study is to reveal the mechanisms involved in the nitridation process with emphasis on the role of hydrogen. From the temperature dependence of the amount of nitrogen in the films the effective activation energy for nitrogen incorporation in this initial stage was deduced.

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