Diffusion model for the crystal growth of Pr1+xBa2−xCu3O7–δ by the top seeded crystal pulling method

1997 ◽  
Vol 12 (11) ◽  
pp. 2880-2888 ◽  
Author(s):  
Minoru Tagami ◽  
Takateru Umeda ◽  
Yuh Shiohara
Keyword(s):  
Ternary Phase Diagram ◽  
Diffusion Flux ◽  
Growth Interface ◽  
Self Diffusion ◽  
Solidification Model ◽  
Flux Balance ◽  
Tie Lines ◽  
Rich Liquid ◽  
Self Diffusion Coefficient ◽  
Good Agreement

A solidification model for Pr1+xBa2−xCu3O7−δ ternary oxides by the top seeded crystal pulling (SRL–CP: Solute Rich Liquid–Crystal Pulling) method is presented in which the composition of the grown single crystals is estimated from the starting composition in the crucible. This model involves the diffusion flux balance of each element at the growth interface in the liquid considering equilibrium tie-lines in the PrOy–BaO–CuO ternary phase diagram which have been obtained experimentally. The self-diffusion coefficient for Pr and the interdiffusivities for Ba and Cu in the liquid are used in this model because this liquid is a dilute solution for Pr. The calculated results are in good agreement with the experimental ones.

scholarly journals Self-Diffusion in Molten Silver Nitrate

1966 ◽  
Vol 21 (3) ◽  
pp. 276-278 ◽  
Author(s):  
C.-A. Sjöblom ◽  
J. Andersson
Keyword(s):  
Diffusion Coefficient ◽  
Silver Nitrate ◽  
Temperature Interval ◽  
Glass Fibre ◽  
The Self ◽  
Paper Strip ◽  
Self Diffusion ◽  
Sources Of Error ◽  
Self Diffusion Coefficient ◽  
Good Agreement

The self-diffusion coefficient of the Ag+-ion in molten AgNO3 has been measured with the glass fibre paper strip technique in the temperature interval 220—336 °C. The result can be described by the equationD=3.2 × 10—4 exp{-3400/(RT)} cm2s—1.A comparison with the results obtained by other workers shows good agreement between the two sets of values. Possible sources of error are discussed.

Determination of Diffusion Coefficient of Cation Vacancies in Nickel Oxide

1969 ◽  
Vol 24 (3) ◽  
pp. 441-443 ◽  
Author(s):  
Romano Morlotti
Keyword(s):  
Electrical Conductivity ◽  
Diffusion Coefficient ◽  
Nickel Oxide ◽  
Equilibrium Concentration ◽  
The Self ◽  
Self Diffusion ◽  
Partial Pressures ◽  
Self Diffusion Coefficient ◽  
Good Agreement

AbstractPolycrystalline NiO samples were equilibrated with different oxygen partial pressures from 10-3 to 1 Atm in the temperature range 750 °C -1000 °C. Transient electrical conductivity was measured until a new equilibrium was attained after changing the oxygen partial pressure. By the time dependence of the electrical conductivity in isothermal conditions the diffusion coefficient of nickel vacancies was determined. Using the pertinent value for the vacancies equilibrium concentration, the self-diffusion coefficient of nickel in nickel oxide was obtained in good agreement with literature data.

Short-time self-diffusion of nearly hard spheres at an oil–water interface

2009 ◽  
Vol 618 ◽  
pp. 243-261 ◽  
Author(s):  
Y. PENG ◽  
W. CHEN ◽  
TH. M. FISCHER ◽  
D. A. WEITZ ◽  
P. TONG
Keyword(s):  
Diffusion Coefficient ◽  
Surface Coverage ◽  
Hard Spheres ◽  
Hydrodynamic Interactions ◽  
Water Interface ◽  
Self Diffusion ◽  
Oil Water ◽  
Short Time ◽  
Self Diffusion Coefficient ◽  
Good Agreement

Optical microscopy and multi-particle tracking are used to study hydrodynamic interactions of monodisperse polymethylmethacrylate (PMMA) spheres at a decalin–water interface. The short-time self-diffusion coefficient measured at low surface coverage has the formDSS(n) = αD0(1 − βn), wherenis the area fraction occupied by the particles, andD0is the Stokes–Einstein diffusion coefficient in the bulk suspension of PMMA spheres in decalin. The measured values of α are found to be in good agreement with the numerical calculation for the drag coefficient of interfacial particles. The measured values of β differ from that obtained for bulk suspensions, indicating that hydrodynamic interactions between the particles have interesting new features at the interface.

Transport and Surface Properties of Liquid Metals using their Diffusion Data

2016 ◽  
Vol 4 (2) ◽  
pp. 137-140
Author(s):  
R. Lalneihpuii ◽  
◽  
Raj Kumar Mishra
Keyword(s):  
Surface Properties ◽  
Potential Surface ◽  
Liquid Metals ◽  
Excess Entropy ◽  
Scaling Law ◽  
Atomic Diffusion ◽  
Self Diffusion ◽  
Square Well ◽  
Self Diffusion Coefficient ◽  
Good Agreement

The atomic diffusion in liquid Na, K, Cs, Mg, Al, In and Pb have been evaluated from the well-known Einstein’s formula of self-diffusion coefficient, D  D  kBT ⎞ under square well (SW) interaction. The friction coefficient, ( of liquid    ⎝ ⎠ metals has been computed on the basis of Helfand-Rice-Nachtrieb approach under Helfand’s linear trajectory (LT) approximation. Shear viscosity of liquid metals were determined using modified Stokes-Einstein equation for SW potential. Dzugutov’s scaling was modified for SW interaction and has been employed to compute excess entropy of the considered liquids. The isothermal compressibility of liquid metals was determined using equation of state of SW potential. Surface entropy of these liquids has been determined through temperature derivative of surface tension. Dzugutov’s scaling law has also been tested in these liquid metals. It is found that the various transport and surface properties of these liquid metals extracted from the diffusion coefficients are in a good agreement with the experimental data.

Self-Transport, Electro-Convection and Effective Self-Diffusion in Liquid Rubidium Metal

1967 ◽  
Vol 22 (2) ◽  
pp. 215-219 ◽  
Author(s):  
A. Norden ◽  
A. Lodding
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficients ◽  
Mass Effect ◽  
Small Current ◽  
Self Diffusion ◽  
Zero Current ◽  
Electro Osmosis ◽  
Self Diffusion Coefficient ◽  
Dependent Mechanism ◽  
Good Agreement

Isotope electrotransport in liquid Rb has been measured. Results of earlier measurements of the mass effect μ have been confirmed and their accuracy further improved. μ ranges from 2 x 10-5 at the m.p. to 10-4 at 400°C. Up to about 200°C the temperature dependence of μ is similar to that of the (theoretically computed) self-diffusion coefficient. At higher temperatures the apparent “activation energy” increases.With the aid of electrotransport, electro-convection in the liquid metal has been studied. Analysis of data at three different currents indicates that in horizontal 0.5 mm i.d. capillaries, at less than some 9 Amps, the main source of electro-convection in Rb is an I2 sensitive mechanism, probably electro-osmosis. At higher currents an I4 dependent mechanism may become dominant. A relatively small current independent term may influence the effective self-diffusion. The zero-current values of the effective self-diffusion coefficients are computed. Between 333° and 500°K they can be represented by (Deff) 0=5.7 x 10–4 exp (-1910/R T), with about 15 percent error margin in “activation energy”. These values are in good agreement with self-diffusion coefficients as calculated from experimental viscosity.

scholarly journals Effect of Modification on the Fluid Diffusion Coefficient in Silica Nanochannels

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4030
Author(s):  
Gengbiao Chen ◽  
Zhiwen Liu
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Coefficients ◽  
Surface Effect ◽  
Bulk Water ◽  
Self Diffusion ◽  
Average Diffusion Coefficient ◽  
Average Diffusion ◽  
Chain Lengths ◽  
Fluid Diffusion ◽  
Self Diffusion Coefficient

The diffusion behavior of fluid water in nanochannels with hydroxylation of silica gel and silanization of different modified chain lengths was simulated by the equilibrium molecular dynamics method. The diffusion coefficient of fluid water was calculated by the Einstein method and the Green–Kubo method, so as to analyze the change rule between the modification degree of nanochannels and the diffusion coefficient of fluid water. The results showed that the diffusion coefficient of fluid water increased with the length of the modified chain. The average diffusion coefficient of fluid water in the hydroxylated nanochannels was 8.01% of the bulk water diffusion coefficient, and the diffusion coefficients of fluid water in the –(CH2)3CH3, –(CH2)7CH3, and –(CH2)11CH3 nanochannels were 44.10%, 49.72%, and 53.80% of the diffusion coefficients of bulk water, respectively. In the above four wall characteristic models, the diffusion coefficients in the z direction were smaller than those in the other directions. However, with an increase in the silylation degree, the increased self-diffusion coefficient due to the surface effect could basically offset the decreased self-diffusion coefficient owing to the scale effect. In the four nanochannels, when the local diffusion coefficient of fluid water was in the range of 8 Å close to the wall, Dz was greater than Dxy, and beyond the range of 8 Å of the wall, the Dz was smaller than Dxy.

scholarly journals Insights into the interactions and dynamics of a DES formed by phenyl propionic acid and choline chloride

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Parisa Jahanbakhsh Bonab ◽  
Alireza Rastkar Ebrahimzadeh ◽  
Jaber Jahanbin Sardroodi
Keyword(s):  
Diffusion Coefficient ◽  
Liquid Phase ◽  
Propionic Acid ◽  
Structural Parameters ◽  
Choline Chloride ◽  
Self Diffusion ◽  
Phenyl Propionic Acid ◽  
Donor And Acceptor ◽  
Experimental Values ◽  
Self Diffusion Coefficient

AbstractDeep eutectic solvents (DESs) have received much attention in modern green chemistry as inexpensive and easy to handle analogous ionic liquids. This work employed molecular dynamics techniques to investigate the structure and dynamics of a DES system composed of choline chloride and phenyl propionic acid as a hydrogen bond donor and acceptor, respectively. Dynamical parameters such as mean square displacement, liquid phase self-diffusion coefficient and viscosity are calculated at the pressure of 0.1 MPa and temperatures 293, 321 and 400 K. The system size effect on the self-diffusion coefficient of DES species was also examined. Structural parameters such as liquid phase densities, hydrogen bonds, molecular dipole moment of species, and radial and spatial distribution functions (RDF and SDF) were investigated. The viscosity of the studied system was compared with the experimental values recently reported in the literature. A good agreement was observed between simulated and experimental values. The electrostatic and van der Waals nonbonding interaction energies between species were also evaluated and interpreted in terms of temperature. These investigations could play a vital role in the future development of these designer solvents.

Self-diffusion coefficient of lithium in lithium oxide

1979 ◽  
Vol 87 (2-3) ◽  
pp. 341-344 ◽  
Author(s):  
Y. Oishi ◽  
Y. Kamei ◽  
M. Akiyama ◽  
T. Yanagi
Keyword(s):  
Diffusion Coefficient ◽  
Lithium Oxide ◽  
Self Diffusion ◽  
Self Diffusion Coefficient
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