Towards Measuring the Pu Self-Diffusion Coefficient in Polycrystalline U0.55Pu0.45O2±x

This paper describes an original method to measure the plutonium self-diffusion coefficient in the mixed oxide U0.55Pu0.45O2±x. This method is based on using 242Pu as a tracer atom. A thin film of the tracer was deposited on the well-polished surface of the samples and then diffusion annealings were performed from 1500°C to 1700°C, in an Ar-H2 5% atmosphere. The oxygen potential was fixed at-395 kJ.mol-1. After annealing, the 242Pu self-diffusion profiles were established by means of secondary ion mass spectrometry (SIMS). The 242Pu concentration profiles were determined by assessing the relative U, Am and Pu ionisation yields according to the experimental parameters. The choice of favourable experimental conditions and the relevance of the resulting concentration profiles are discussed at length.

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Zinc Self-Diffusion in ZnO

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.237-240.163 ◽

2005 ◽

Vol 237-240 ◽

pp. 163-168 ◽

Cited By ~ 6

Author(s):

M.A.N. Nogueira ◽

Antônio Claret Soares Sabioni ◽

Wilmar Barbosa Ferraz

Keyword(s):

Diffusion Coefficient ◽

Grain Boundary ◽

Diffusion Coefficients ◽

Boundary Diffusion ◽

Volume Diffusion ◽

Grain Boundary Diffusion ◽

Polished Surface ◽

Self Diffusion ◽

Zinc Diffusion ◽

Diffusion Profiles

This work deals with the study of zinc self-diffusion in ZnO polycrystal of high density and of high purity. The diffusion experiments were performed using the 65Zn radioactive isotope as zinc tracer. A thin film of the tracer was deposited on the polished surface of the samples, and then the diffusion annealings were performed from 1006 to 1377oC, in oxygen atmosphere. After the diffusion treatment, the 65Zn diffusion profiles were established by means of the Residual Activity Method. From the zinc diffusion profiles were deduced the volume diffusion coefficient and the product dDgb for the grain-boundary diffusion, where d is the grain-boundary width and Dgb is the grain-boundary diffusion coefficient. The results obtained for the volume diffusion coefficient show good agreement with the most recent results obtained in ZnO single crystals using stable tracer and depth profiling by secondary ion mass spectrometry, while for the grain-boundary diffusion there is no data published by other authors for comparison with our results. The zinc grain-boundary diffusion coefficients are ca. 4 orders of magnitude greater than the volume diffusion coefficients, in the same experimental conditions, which means that grain-boundary is a fast path for zinc diffusion in polycrystalline ZnO.

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Diffusion of Arsenic in Single Crystalline CoSi2

MRS Proceedings ◽

10.1557/proc-402-51 ◽

1995 ◽

Vol 402 ◽

Cited By ~ 6

Author(s):

A. Pisch ◽

J. Cardenas ◽

B. G. Svensson ◽

C. S. Petersson

Keyword(s):

Diffusion Coefficient ◽

Secondary Ion Mass Spectrometry ◽

Lattice Diffusion ◽

High Dose ◽

Exponential Factor ◽

Self Diffusion ◽

Different Temperatures ◽

Secondary Ion ◽

Self Diffusion Coefficient ◽

Different Doses

AbstractThe lattice diffusion of arsenic in CoSi2 has been studied in the temperature range from 750°C to 950°C. Two types of bulk samples were used: single crystals prepared by a modified Czochralski pulling technique from a radio frequency levitated melt and polycrystals synthesised by quenching from the melt. The latter samples were subsequently annealed in vacuum at 900°C and displayed grain sizes in the millimetre range. Starting from an ion implanted arsenic profile with two different doses (5·1014 and 5·1015 cm−2) the concentration versus depth profiles after annealing at different temperatures and different times were measured using secondary ion mass spectrometry (SIMS). Contrary to previous studies by other authors substantial diffusion has been observed with an activation energy of 3.3 eV and a pre-exponential factor of 7.37 cm2/s for the diffusion coefficient. These values are very close to the self diffusion coefficient of Si in CoSi2 suggesting that the As atoms migrate via thermal vacancies on nearest neighbour lattice sites by a similar type of mechanism as the Si (and Co) atoms. In the high dose implanted polycrystalline samples arsenic precipitation occurred which gives an estimate for the solid solubility in the 1019 atoms/cm3 range at 800 °C.

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Electrointercalation of silver into 2H–NbSe2

Canadian Journal of Physics ◽

10.1139/p81-165 ◽

1981 ◽

Vol 59 (9) ◽

pp. 1267-1277 ◽

Cited By ~ 13

Author(s):

J. T. Folinsbee ◽

M. H. Jericho ◽

R. H. March ◽

D. A. Tindall

Keyword(s):

Diffusion Coefficient ◽

Electron Beam ◽

Critical Concentration ◽

Sample Surface ◽

Radioactive Tracer ◽

Concentration Profiles ◽

Self Diffusion ◽

Sharp Fronts ◽

Two Stages ◽

Self Diffusion Coefficient

The electrointercalation of Ag into single crystals of 2H–NbSe2 was studied. The distribution of Ag in the samples was measured with an electron beam probe. Intercalation generally proceeded in two stages, with the Van der Waals gaps, near the sample surface, appearing to intercalate first, while a critical concentration, [Formula: see text] of Ag, was required before intercalation in the bulk took place. The Ag concentration profiles were generally characterized by sharp fronts which remained stationary for long periods of time after intercalation was discontinued. Radioactive tracer measurements gave Ag self-diffusion coefficient of [Formula: see text] for [Formula: see text].

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Experimental Conditions to Obtain an Accurate Value of Self-Diffusion Coefficient by Serial Sectioning Technique

Journal of the Ceramic Association Japan ◽

10.2109/jcersj1950.82.945_291 ◽

1974 ◽

Vol 82 (945) ◽

pp. 291-294 ◽

Cited By ~ 1

Author(s):

Seiichi KURIHARA ◽

Kazuo FUEKI ◽

Takashi MUKAIBO

Keyword(s):

Diffusion Coefficient ◽

Serial Sectioning ◽

Experimental Conditions ◽

Self Diffusion ◽

Self Diffusion Coefficient

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Self-Diffusion in Intrinsic and Extrinsic Silicon Using Isotopically Pure 30Silicon Layer

MRS Proceedings ◽

10.1557/proc-669-j3.3 ◽

2001 ◽

Vol 669 ◽

Cited By ~ 1

Author(s):

Yukio Nakabayashi ◽

Hirman I. Osman ◽

Toru Segawa ◽

Kazunari Toyonaga ◽

Satoru Matsumoto ◽

...

Keyword(s):

Mass Spectrometry ◽

Diffusion Coefficient ◽

Temperature Dependence ◽

Diffusion Coefficients ◽

Secondary Ion Mass Spectrometry ◽

Intrinsic Diffusion Coefficient ◽

Intrinsic Diffusion ◽

Self Diffusion ◽

Secondary Ion ◽

Diffusion Profiles

ABSTRACTSilicon self–diffusion coefficients were measured in intrinsic and extrinsic silicon from870 to 1070°C using isotopically pure 30Si layer. 30Si diffusion profiles are determined by secondary ion mass spectrometry. The temperature dependence of intrinsic diffusion coefficient in bulk Si isobtained. Comparing it in heavily As-doped or B-doped Si, it is found that Si self-diffusion is entirely mediated by interstitialcy mechanism at lower temperatures below 870°C.

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Effect of Modification on the Fluid Diffusion Coefficient in Silica Nanochannels

Molecules ◽

10.3390/molecules26134030 ◽

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.

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

Scientific Reports ◽

10.1038/s41598-021-85260-z ◽

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.

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Transport and Electromechanical Properties of Ca3TaGa3Si2O14 Piezoelectric Crystals at Extreme Temperatures

MRS Advances ◽

10.1557/adv.2019.16 ◽

2019 ◽

Vol 4 (09) ◽

pp. 515-521

Author(s):

Yuriy Suhak ◽

Ward L. Johnson ◽

Andrei Sotnikov ◽

Hagen Schmidt ◽

Holger Fritze

Keyword(s):

Secondary Ion Mass Spectrometry ◽

Tone Burst ◽

Total Conductivity ◽

Transport Mechanisms ◽

Electromechanical Properties ◽

Self Diffusion ◽

Oxygen Ion ◽

Piezoelectric Strain ◽

Secondary Ion ◽

Diffusion Profiles

ABSTRACTTransport mechanisms in structurally ordered piezoelectric Ca3TaGa3Si2O14 (CTGS) single crystals are studied in the temperature range of 1000-1300 °C by application of the isotope 18O as a tracer and subsequent analysis of diffusion profiles of this isotope using secondary ion mass spectrometry (SIMS). Determined oxygen self-diffusion coefficients enable calculation of oxygen ion contribution to the total conductivity, which is shown to be small. Since very low contributions of the cations have to be expected, the total conductivity must be dominated by electron transport. Ion and electron conductivities are governed by different mechanisms with activation energies (1.9±0.1) eV and (1.2±0.07) eV, respectively. Further, the electromechanical losses are studied as a function of temperature by means of impedance spectroscopy on samples with electrodes and a contactless tone-burst excitation technique. At temperatures above 650 °C the conductivity-related losses are dominant. Finally, the operation of CTGS resonators is demonstrated at cryogenic temperatures and materials piezoelectric strain constants are determined from 4.2 K to room temperature.

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