Determination of silicon point defect properties from oxidation enhanced diffusion of buried layers

1993 ◽  
Vol 63 (6) ◽  
pp. 800-802 ◽  
Author(s):  
Anuradha M. Agarwal ◽  
Scott T. Dunham
Keyword(s):  
Point Defect ◽  
Enhanced Diffusion ◽  
Buried Layers

The Study of the Interaction of the Components of Imitator-Glasses of Glassified Radioactive Wastes With Various Surrounding Rocks

1981 ◽  
Vol 6 ◽  
Author(s):  
V. I. Spitsyn ◽  
A. A. Minaev ◽  
L. I. Barsova ◽  
P. Ya. Glazunov ◽  
V. N. Vetchkanov
Keyword(s):  
Gamma Irradiation ◽  
High Temperatures ◽  
Phosphate Glass ◽  
Phosphate Glasses ◽  
Radioactive Wastes ◽  
X Ray ◽  
Enhanced Diffusion ◽  
Radiation Enhanced Diffusion

ABSTRACTThis work is one of the first attempts to work out a proper technique for the determination of the diffusion of the phosphate glass components into various rocks by using X-ray microanalysis. Under study was thermal and radiationenhanced diffusion of phosphorus, chromium from phosphate glasses into the samples of basalt, metagabbro, metadunite and quartz at high temperatures (to 600°) during gamma irradiation. Radiation enhanced diffusion of ions into rocks.

Determination of the energy of electron in a quantum wire with a point defect

2014 ◽  
Vol 49 (2) ◽  
pp. 43-49 ◽  
Author(s):  
D. M. Sedrakian ◽  
D. A. Badalyan ◽  
L. R. Sedrakyan
Keyword(s):  
Point Defect ◽  
Quantum Wire

Determination of silicon point defect parameters and reaction barrier energies from gold diffusion experiments

1995 ◽  
Vol 77 (3) ◽  
pp. 1320-1322 ◽  
Author(s):  
K. Ghaderi ◽  
G. Hobler ◽  
M. Budil ◽  
L. Mader ◽  
H. J. Schulze
Keyword(s):  
Point Defect ◽  
Reaction Barrier ◽  
Gold Diffusion

Determination of Residual Oil Saturation Using Enhanced Diffusion

1998 ◽  
Author(s):  
Ridvan Akkurt ◽  
Dave Marschall ◽  
Ramsin Y. Eyvazzadeh ◽  
John S. Gardner ◽  
Duncan Mardon ◽  
...  
Keyword(s):  
Residual Oil ◽  
Oil Saturation ◽  
Residual Oil Saturation ◽  
Enhanced Diffusion

Determination of Residual Oil Saturation by Use of Enhanced Diffusion

1999 ◽  
Vol 2 (03) ◽  
pp. 303-309 ◽  
Author(s):  
Ridvan Akkurt ◽  
Dave Marschall ◽  
R.Y. Eyvazzadeh ◽  
J.S. Gardner ◽  
Duncan Mardon ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Surface Relaxation ◽  
Diffusion Method ◽  
Residual Oil ◽  
Oil Saturation ◽  
Residual Oil Saturation ◽  
Enhanced Diffusion ◽  
Two Phases ◽  
And Diffusion

Summary The enhanced diffusion method (EDM) exploits the diffusion contrast between oil and water separating their respective nuclear magnetic resonance (NMR) signals. Unlike standard NMR logs acquired with short interecho time (TE), measurements, EDM data are acquired using long T E accentuating diffusion. Fundamentally the EDM establishes an absolute upper bound for the T2 of water, thus any T2's greater than this limit unambiguously indicates that oil is present. The EDM's best application is with intermediate viscosity oils (approximately 1 to 50 cp) complementing other NMR hydrocarbon-typing applications designed for lighter hydrocarbons (i.e., the differential spectrum method). While expanding the viscosity range of NMR hydrocarbon-typing applications, the EDM also provides a method by which to determine residual oil saturation (ROS), which is the main focus of this article. The potential use of NMR as a direct indicator of hydrocarbon saturation via techniques such as the differential spectrum method (DSM) has generated significant interest in the petrophysical community in recent years. Although originally developed for applications involving natural gas, the DSM has also been used successfully in light hydrocarbon environments. However, success has been limited to the low end of the viscosity spectrum because of the T1 separation requirements between the brine and hydrocarbon phases. The T1 separation requirement imposed on diffusion applications in higher viscosity oils can be eliminated by using the EDM, where diffusion is turned into the dominant relaxation mode for the wetting brine phase. Given that brine is more diffusive than the hydrocarbons, the longest apparent T2 from the brine phase can be made short enough to cause separation between the two phases in T2 space, thereby eliminating the need for T1 separation. Wait time manipulation can then be used to quantify hydrocarbon volumes when the two phases are separated in the T2 domain. In this article we focus on determination of the residual oil saturation using the EDM, while also providing guidelines for job screening and acquisition parameter selection. Several case histories that are provided are used to illustrate the basic concepts and different methodologies available. Introduction The enhanced diffusion method is a new method developed to distinguish oil and water NMR signals in a gradient magnetic field by exploiting the diffusion contrast between the two fluids. The method is applicable for moderate oil viscosities, approximately in the ~1 to ~50 cp range. The major objective of this article is to discuss EDM signal processing techniques for residual oil saturation, and the reader is referred to existing literature1 for a detailed discussion regarding the petrophysical concepts and related laboratory measurements of the EDM. A secondary objective is to provide guidelines that can be used to screen potential EDM applications and to determine optimal acquisition parameters. Within the context used in this article, residual oil saturation is defined as the oil saturation in the flushed zone after drilling fluid invasion, and the terms residual and flushed zone oil saturation are used interchangeably. Theory The basic concept of the EDM is to turn diffusion into an effective transverse relaxation mechanism while minimizing the dominance of surface relaxation by acquiring NMR logs at long interecho times. Three different mechanisms, which operate in parallel, contribute to the overall apparent relaxation rate of water in porous media: $$1/T {2AW}=1/T {2BW}+1/T {2SW}+1/T {2DW},\eqno ({\rm 1})$$ where the subscript W stands for water, and A, B, S, D denote apparent, bulk, surface-induced, and diffusion-induced mechanisms, respectively. The surface and diffusion induced relaxation rates are given by $$1/T {2SW}=\rho {2}S/V,\eqno ({\rm 2})$$$$1/T {2DW}=((\gamma GT {E})^{2}D {0W})/12,\eqno ({\rm 3})$$ where ?2 is surface relaxivity, S/V is the surface-to-volume ratio, ? is the gyromagnetic ratio, G is the magnetic field gradient, TE is the interecho time, and D0W is the self-diffusion coefficient of water. In standard logging modes using short TE surface relaxation dominates since (1) T2BW is very long, especially at elevated temperatures, and (2) T2BW is also very long because of the short TE values used, despite large magnetic field gradients of the logging tools.

A Comprehensive Model for Carbon Suppression of Boron Transient Enhanced Diffusion

2001 ◽  
Vol 669 ◽  
Author(s):  
Julie L. Ngau ◽  
Peter B. Griffin ◽  
James D. Plummer
Keyword(s):  
Point Defect ◽  
Recent Work ◽  
Comprehensive Model ◽  
Pairing Mechanism ◽  
Diffusion Behavior ◽  
Interstitial Carbon ◽  
Enhanced Diffusion ◽  
Transient Enhanced Diffusion ◽  
Single Temperature ◽  
Carbon Interstitial

ABSTRACTIn this work, the time evolution of B transient enhanced diffusion (TED) suppression due to the incorporation of 0.018% substitutional carbon in silicon was studied. The combination of having low C concentrations, which reduce B TED without completely eliminating it, and having diffused B profiles for several times at a single temperature provides much data upon which various models for the suppression of B TED can be tested. Recent work in the literature has indicated that the suppression of B TED in C-rich Si is caused by non-equilibrium Si point defect concentrations, specifically the undersaturation of Si self-interstitials, that result from the coupled out-diffusion of carbon interstitials via the kick-out and Frank-Turnbull reactions. Attempts to model our data with these two reactions revealed that the time evolved diffusion behavior of B was not accurately simulated and that an additional reaction that further reduces the Si self-inter- stitial concentration was necessary. In this work, we incorporate a carbon interstitial, carbon substitutional (CiCs) pairing mechanism into a comprehensive model that includes the C kick-out reaction, C Frank-Turnbull reaction, {311} defects, and boron interstitial clusters (BICs) and demonstrate that this model successfully simulates C suppression of B TED at 750 °C for anneal times ranging from 10 s to 60 min.

Modeling of TED Point Defect Paramater Extraction

2002 ◽  
Vol 717 ◽  
Author(s):  
Heidi Meyer ◽  
Scott T. Dunham
Keyword(s):  
Point Defect ◽  
Diffusion Capacity ◽  
Enhanced Diffusion ◽  
Self Diffusion ◽  
Transient Enhanced Diffusion ◽  
Two Factors

AbstractThe work investigates simple transient enhanced diffusion (TED) behavior, which is a reflection of the interstitial behavior in the system. The analysis shows that TED depends mainly on two factors: the intial demage profiles and the DICI product. We find that, based on these two inputs, the extent of TED can be accurately diffusion capacity (DICI) which is compared to values previously extracted from diffcusion and silicon self-diffusion experiments.

MIGRATION ENTHALPY OF THERMAL VACANCIES BY POSITRON SPECTROSCOPY

2005 ◽  
Vol 12 (04) ◽  
pp. 493-498
Author(s):  
EMAD A. BADAWI
Keyword(s):  
Point Defect ◽  
Positron Annihilation Lifetime ◽  
Defect Migration ◽  
Positron Spectroscopy ◽  
Vacancy Site ◽  
Al Mg Alloys ◽  
Migration Enthalpy ◽  
Sensitive Method ◽  
Enthalpy Data

The trapping of positrons at vacancy site in some materials provide a new and sensitive method for the equilibrium determination of point defect migration enthalpy. Data are presented for commercial Al–Mg alloys and fitted to a model allowing presentation in the form of Arrhenius plots, hence the migration enthalpy [Formula: see text] can be determined by positron annihilation lifetime technique (PALT). The results show that as the concentration of Mg increases the value of [Formula: see text] increases too.

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