Carbon and the Kinetics of Oxygen Precipitation in Silicon

1982 ◽  
Vol 14 ◽  
Author(s):  
R.F. Pinizzotto ◽  
S. Marks
Keyword(s):  
Oxygen Content ◽  
Oxygen Concentration ◽  
Carbon Concentration ◽  
Oxygen Solubility ◽  
Low Oxygen ◽  
Subsequent Increase ◽  
High Oxygen Content ◽  
Oxygen Precipitation ◽  
Precipitate Growth ◽  
Initial Oxygen

ABSTRACTOxygen precipitation in Czochralski silicon has been studied as a function of anneal time, oxygen concentration and carbon concentration using FTIR. It was found that the oxygen supersaturation controls the precipitation kinetics in high oxygen content samples, whereas the carbon concentration is of prime importance in low oxygen content samples. The decrease in sustitutional carbon concentration after nucleation and its subsequent increase with extended growth anneals supports the view that carbon affects precipitate nucleation, but not precipitate growth. The measured oxygen solubility at 1000°C was found to depend on both the initial oxygen concentration and the initial carbon concentration.

Large Eddy Simulation of Multiple-Stage Ignition Process of n-Heptane Spray Flame

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Wanhui Zhao ◽  
Lei Zhou ◽  
Wenjin Qin ◽  
Haiqiao Wei
Keyword(s):  
Oxygen Concentration ◽  
Mixture Fraction ◽  
Ignition Process ◽  
Low Oxygen ◽  
Nonpremixed Combustion ◽  
Eddy Simulation ◽  
Spray Flames ◽  
Large Eddy ◽  
Initial Oxygen ◽  
Oxygen Concentrations

Large eddy simulation of n-heptane spray flames is conducted to investigate the multiple-stage ignition process under extreme (low-temperature, low oxygen, and high-temperature, high-density) conditions. At low oxygen concentrations, the first-stage ignition initiates in the fuel-rich region and then moves to stoichiometric equivalence ratio regions by decreasing the initial temperature. It is also clear that at high temperatures, high oxygen concentrations, or high densities, the reactivity of the mixture is enhanced, where high values of progress variable are observed. Analysis of key intermediate species, including acetylene (C2H2), formaldehyde (CH2O), and hydroxyl (OH) in the mixture fraction and temperature space provides valuable insights into the complex combustion process of the n-heptane spray flames under different initial conditions. The results also suggest that C2H2 appears over a wider range in the mixture fraction space at higher temperature or oxygen concentration condition, implying that it mainly forms at the fuel-rich regions. The initial oxygen concentration of the ambient gas has great influence on the formation and oxidization of C2H2, and the maximum temperature depends on the initial oxygen concentration. OH is mainly formed at the stoichiometric equivalence ratio region, which moves to high-temperature regions very quickly especially at higher oxygen concentrations. Finally, analysis of the premixed and nonpremixed combustion regimes in n-heptane spray flames is also conducted, and both premixed and nonpremixed combustion coexist in spray flames.

scholarly journals False Oxygen Consumption Effect and Factors Causing It

2011 ◽  
Vol 2011 ◽  
pp. 1-5
Author(s):  
M. V. Miniaev ◽  
M. B. Belyakova ◽  
N. V. Kostiuk ◽  
D. V. Leshchenko
Keyword(s):  
Oxygen Consumption ◽  
Low Temperature ◽  
Oxygen Content ◽  
Incubation Medium ◽  
Low Oxygen ◽  
Salting Out ◽  
Low Concentration ◽  
Initial Oxygen Content ◽  
Initial Oxygen

False oxygen consumption effect characterized by a decrease of the polarographic sensor readings by the introduction of neutral microadditives into the incubation medium was modeled and tested. These neutral microadditives neither consume oxygen nor cause its consumption by other components of the medium. It is shown that microadditives less than 3% of the volume of incubation medium can cause statistically significant effect of false oxygen consumption more than 4% of the initial oxygen content. The effect can reach more than 15% at higher volumes of additives. The most important properties of additives enhancing the effect are low oxygen content, low temperature, and low concentration of oxygen salting out components.

The Difference between Iodine Number and Nitrogen Surface Area Determinations for Carbon Blacks

2006 ◽  
Vol 79 (1) ◽  
pp. 120-134 ◽  
Author(s):  
J. B. Donnet ◽  
A. Santini ◽  
D. Maafa ◽  
H. Balard ◽  
F. Padella ◽  
...  
Keyword(s):  
Iodine Number ◽  
Surface Area ◽  
Oxygen Content ◽  
Analytical Relationship ◽  
Low Oxygen ◽  
High Oxygen Content ◽  
Carbon Blacks ◽  
Elementary Analysis ◽  
Disordered Carbon ◽  
The Difference

Abstract The iodine number furnishes surface area values in disagreement with the NSA technique in the case of disordered carbon i.e., lower than NSA in case of high oxygen content (more than 2%), but higher for low oxygen content (less than 1%). Because carbon blacks are solids which exhibit graphitic structure, some milled graphite samples, were taken as model materials and analyzed. Surface area was determined by using both NSA and N≩I2 techniques, and the difference between the results given by the two techniques were observed and related to the microstructure, which was analyzed by using X-ray diffraction, Raman spectroscopy, and the oxygen content was measured by using elementary analysis. Two different models of iodine adsorption have been proposed, respectively, for the graphitic parts of the graphite grains and for the disordered part of the grains. An analytical relationship between the differences of iodine and nitrogen surface area values, microstructure and oxygen content was proposed and successfully tested. The same relationship was applied to some commercial and experimental carbon black with good results.

scholarly journals Characterization of Municipal Solid Waste Incineration and Flue Gas Emission Under Anoxic Environment in Tibet Plateau

2021 ◽  
Author(s):  
Dan Zeng ◽  
Wenwu Zhou ◽  
Peng Zhou ◽  
Yuechi Che ◽  
Zhiyong Han ◽  
...  
Keyword(s):  
Oxygen Content ◽  
Flue Gas ◽  
Waste Incineration ◽  
Tibet Plateau ◽  
Low Oxygen ◽  
Gas Emission ◽  
High Oxygen Content ◽  
Msw Incineration ◽  
Air Temperatures ◽  
Plateau Area

Abstract Waste incineration is a process of full combustion reaction between waste and oxygen at high temperature. It is a new problem whether the special natural environmental conditions of Tibet Plateau, such as low air pressure, low oxygen content and low temperature, will affect the waste incineration in the plateau area. In this work, the influence of different parameters on MSW incineration efficiency and flue gas emission were investigated. The results showed that the temperatures exhibited a significant impact on the flue gas emission. Under the lower temperature, CO was determined to be the main pollutant. With the increase of temperature, NOx became the main pollutant. The optimal temperature range of flue gas emission was between 800ºC to 900ºC. A slight negative pressure in incinerator was benefit for incineration system safety and flue gas emissions. The optimal range was -50Pa to 0Pa. Lower oxygen content (3%-6%) in the incinerator affected the incineration efficiency and flue gas emission. Meanwhile, the high oxygen content had no obvious impact on the flue gas emission, but the cost increased and the service life of the incinerator was affected. The optimal oxygen content in the incinerator was controlled at 6%-8%. Furthermore, the air temperatures, pressures and oxygen content in the natural environment had no significant effect on MSW incineration process. Increasing the air volume would bring about the increase of N 2 in the incinerator. This work provides the basic data support for MSW incineration technology in plateau area.

The Effect of Oxygen on the Thermal Stability of Si1−xGex Strained Layers Grown by Limited Reaction Processing

1991 ◽  
Vol 220 ◽  
Author(s):  
D. B. Noble ◽  
J. L. Hoyt ◽  
P. Kuo ◽  
W. D. Nix ◽  
J. F. Gibbons ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Solid Solution ◽  
Oxygen Content ◽  
Low Oxygen ◽  
Strained Layers ◽  
High Oxygen Content ◽  
Solid Solution Strengthening ◽  
Solution Strengthening ◽  
Effect Of Oxygen ◽  
Content Support

ABSTRACTSi1−xGex layers containing 2×1020 oxygen atoms/cm3 exhibit an enhancement in thermal stability when compared to similar films (comparable Ge content and thickness) with 2 orders of magnitude less oxygen. X-ray measurements of the lattice constants in the strained films indicate that the oxygen does not substantially change the amount of strain in the layers. A prediction of the effect of oxygen based on solid solution strengthening theory is shown to be consistent with experimental annealing results. In addition, experimental measurements of slower misfit dislocation velocities in the layers with high oxygen content compared to those measured in films with low oxygen content, support the idea of solid solution strengthening. It is therefore likely that oxygen impedes the kinetics of dislocation formation.

Oxygen Control for Wet Clean Process on Single Wafer Platform

2016 ◽  
Vol 255 ◽  
pp. 260-264 ◽  
Author(s):  
Lucile Broussous ◽  
Kevin Hoarau ◽  
Come de Buttet ◽  
Stephane Zoll
Keyword(s):  
Oxygen Uptake ◽  
Oxygen Content ◽  
Oxygen Concentration ◽  
Process Optimization ◽  
Low Oxygen ◽  
Oxygen Control ◽  
Full Control ◽  
Wet Processing ◽  
Atmosphere Control ◽  
Wafer Processing

Wet processing with low oxygen content may provides some advantages, however, full control to avoid oxygen uptake during wafer processing remains a challenge for short process industrialization on single wafer tool. Inline oxygen concentration monitoring was used for process optimization. Then, cobalt etch in diluted HF solutions was evaluated depending on the recorded oxygen concentration and hardware available options for atmosphere control in the process chamber.

High Performance Magnets - Microstructure and Coercivity

1999 ◽  
Vol 577 ◽  
Author(s):  
J. Fidler ◽  
S. Sasaki ◽  
E. Estevez-Rams
Keyword(s):  
Energy Density ◽  
Oxygen Content ◽  
Coercive Field ◽  
High Performance ◽  
Magnetic Energy ◽  
Low Oxygen ◽  
Critical Temperatures ◽  
High Oxygen Content ◽  
Magnetic Energy Density ◽  
Strip Cast

ABSTRACTThe importance of newly developed permanent magnetic materials in many electro-, magnetomechanical and electronic applications can be attributed to the drastic improvement of the magnetic energy density product and coercive field. A systematic study has been undertaken in order to determine the influence of oxygen content on microstructure and coercivity of high remanence Nd2Fe14B based sintered magnets. The energy density product >400 kJ/m3 (50 MGOe) and the coercive field of 800 kA/m were obtained after a combination of rubber isostatic and transverse die pressing methods. Magnets of the composition Nd151−xFe78+xB6Cu0.03A10.7 [x= 0-2.5] were prepared using strip cast materials. The high oxygen content of the magnets was gradually decreased from values of 4000-6000 ppm to a value < 1000 ppm. Abnormal grain growth (AGG) of the 2:14:1 grains occurred preferentially in magnets with low oxygen content, thus the squareness of the demagnetisation curve drastically decreased. The oxygen content strongly affects the AGG and the magnets with higher oxygen content have the higher critical temperatures at which the AGG occurs. On the other hand, isotropic magnets tend to have the lower critical temperatures than anisotropic magnets by 10-20°C. In the second part of the paper examples of the influence of intergranular phases, grain size and grain shape observed by TEM on coercivity of sintered and melt-spun Nd-Fe-B magnets are compared.

Radiative Properties of Y-Ba-Cu-0 Films With Variable Oxygen Content

1992 ◽  
Vol 114 (4) ◽  
pp. 958-964 ◽  
Author(s):  
B. I. Choi ◽  
Z. M. Zhang ◽  
M. I. Flik ◽  
T. Siegrist
Keyword(s):  
Oxygen Content ◽  
Optical Constants ◽  
Deposition Process ◽  
Film Deposition ◽  
Radiative Properties ◽  
Low Oxygen ◽  
High Oxygen Content ◽  
Thin Film Optics ◽  
Electron Contribution ◽  
Measurement And Control

The room-temperature radiative properties of YBa2Cu3O7−δ superconducting films with varying oxygen content (δ = 0 to 1) on a LaAlO3 substrate are investigated. The fitting of reflectance spectra using thin-film optics and the Drude-Lorentz model function with multiple oscillators determines the optical constants. The film with high oxygen content (δ = 0) has a metallic optical behavior. A decrease in the oxygen content causes a removal of free carriers, and the film with low oxygen content (δ = 1) acts like a dielectric with a very weak free-electron contribution. Knowledge of the optical constants of oxygen-deficient YBa2Cu3O7-δ films facilitates accurate substrate temperature measurement and control during the film deposition process.

Grain Boundary Modification by Si3N4 Additions and the Effect on Corrosion Behaviors in Two Sintered Nd-Fe-B Magnets

2010 ◽  
Vol 89-91 ◽  
pp. 733-738
Author(s):  
Qiong Zhen Liu ◽  
Lan Ting Zhang ◽  
Ai Dang Shan ◽  
Jian Sheng Wu ◽  
Matahiro Komuro
Keyword(s):  
Grain Size ◽  
Corrosion Resistance ◽  
Oxygen Content ◽  
Corrosion Potential ◽  
Low Oxygen ◽  
High Oxygen Content ◽  
Intergranular Phase ◽  
Microstructure Observation ◽  
Corrosion Behaviors ◽  
Boundary Modification

Two sintered magnets Nd15Dy1.2Fe77Al0.8B6 and Nd22Fe71B7 were modified by intergranular additions of Si3N4. The remanence as well as sintering density of the two magnets increased slightly with appropriate amount of Si3N4 additives. Meanwhile, there was an obvious increase in coercivity of the Nd-rich Nd22Fe71B7 magnet after 0.3 wt. % Si3N4 was added to magnets. Besides the effects on magnetic properties, an improved corrosion resistance was observed. Compared with the native magnets without any additions, corrosion potential of the magnets with Si3N4 additives is more positive and the current density in the anodic branch of the polarization curve is reduced. Microstructure observation reveals that Si3N4 additives have been incorporated into the intergranular phases in the magnets. Si is found to enrich in the Nd-rich intergranular phase with low oxygen content. With the introduction of Si3N4 additives, more intergranular phase with high oxygen content is formed, which may contribute to improved corrosion resistance. In addition, addition of Si3N4 refines the grain size of Nd22Fe71B7.

Sign in / Sign up

Export Citation Format

Share Document