Self-Interstitial Injection Effects on Carbon Diffusion in Silicon At High Temperatures

1985 ◽  
Vol 59 ◽  
Author(s):  
L. A. Ladd ◽  
J. P. Kalejs
Keyword(s):  
High Temperatures ◽  
Carbon Diffusion ◽  
Time Dependent ◽  
Ambient Conditions ◽  
Significant Time ◽  
Temperature Range ◽  
Carbon Diffusivity ◽  
Sims Analysis ◽  
Diffusion Profiles

ABSTRACTCarbon diffusivity is reported for different ambient conditions imposed during annealing of silicon in the temperature range from 800 to 100°C, which produce varying levels of silicon self-interstitial supersaturation. The diffusivities are deduced from SIMS analysis of carbon out-diffusion profiles. Carbon diffusivity is increased by up to a factor of 70 in annealing with phosphorus in-diffusion, and by a factor of as much as seven in an oxidizing ambient, when compared to anneals in a nitrogen ambient. The enhancements tend to decrease above 11000C. This behavior can be explained by attributing the increase in carbon diffusivity to self-interstitial supersaturation which increases the concentration of highly mobile carbon selfinterstitial pairs. Significant time dependent effects were also observed for 800 and 9000C phosphorus in-diffusion conditions.

scholarly journals The combustion of aromatic and alicyclic hydrocarbons. II. The ignition of aromatic hydrocarbons at high temperatures

1939 ◽  
Vol 171 (946) ◽  
pp. 421-433 ◽  
Keyword(s):  
High Temperatures ◽  
Aromatic Hydrocarbons ◽  
Isothermal Oxidation ◽  
Present Communication ◽  
Temperature Range ◽  
Benzene Toluene ◽  
The Subject ◽  
Kinetics Of

In the first paper of this series (Burgoyne 1937) the kinetics of the isothermal oxidation above 400° C of several aromatic hydrocarbons was studied. The present communication extends this work to include the phenomena of ignition in the same temperature range, whilst the corresponding reactions below 400° C form the subject of further investigations now in progress. The hydrocarbons at present under consideration are benzene, toluene, ethylbenzene, n -propylbenzene, o-, m - and p -xylenes and mesitylene.

Effects of Nb doping on thermoelectric properties of Zn4Sb3 at high temperatures

2009 ◽  
Vol 24 (2) ◽  
pp. 430-435 ◽  
Author(s):  
D. Li ◽  
H.H. Hng ◽  
J. Ma ◽  
X.Y. Qin
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
High Temperatures ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Thermoelectric Performance ◽  
Temperature Range ◽  
A Value ◽  
Nb Doping ◽  
Thermal Conductivities

The thermoelectric properties of Nb-doped Zn4Sb3 compounds, (Zn1–xNbx)4Sb3 (x = 0, 0.005, and 0.01), were investigated at temperatures ranging from 300 to 685 K. The results showed that by substituting Zn with Nb, the thermal conductivities of all the Nb-doped compounds were lower than that of the pristine β-Zn4Sb3. Among the compounds studied, the lightly substituted (Zn0.995Nb0.005)4Sb3 compound exhibited the best thermoelectric performance due to the improvement in both its electrical resistivity and thermal conductivity. Its figure of merit, ZT, was greater than the undoped Zn4Sb3 compound for the temperature range investigated. In particular, the ZT of (Zn0.995Nb0.005)4Sb3 reached a value of 1.1 at 680 K, which was 69% greater than that of the undoped Zn4Sb3 obtained in this study.

ON MEASUREMENT OF THERMAL CONDUCTIVITY AT HIGH TEMPERATURES

1961 ◽  
Vol 39 (7) ◽  
pp. 1029-1039 ◽  
Author(s):  
M. J. Laubitz
Keyword(s):  
Thermal Conductivity ◽  
Heat Flow ◽  
High Temperatures ◽  
Mathematical Analysis ◽  
Temperature Range ◽  
Linear Heat ◽  
Flow Systems

A method is given for exact mathematical analysis of linear heat flow systems used in measuring thermal conductivity at high temperatures. It is shown that a popular version of such a system is very sensitive to the alignment of its components, which seriously limits the temperature range of its satisfactory use.

The Influence of Stress on Interstitial Diffusion - Carbon Diffusion Data in Austenite Revisited

2010 ◽  
Vol 297-301 ◽  
pp. 1408-1413 ◽  
Author(s):  
Thomas L. Christiansen ◽  
Marcel A.J. Somers
Keyword(s):  
High Temperatures ◽  
Carbon Diffusion ◽  
Interstitial Diffusion ◽  
Diffusion Data ◽  
Induced Stress ◽  
Induced Stresses ◽  
Expanded Austenite

The present paper addresses the influence of chemical induced stresses on diffusion in interstitial systems. This is exemplified by simulations of carbon diffusion in austenite at high temperatures and it is shown that old well established literature data is flawed by the occurrence of composition induced stress. For the technological relevant system of expanded austenite the diffusion can be dramatically affected by composition induced stress.

The Effect of Carbon/Self-Interstitial Clusters on Carbon Diffusion in Silicon Modeled by Kinetic Monte Carlo Simulations

2000 ◽  
Vol 610 ◽  
Author(s):  
R. Pinachoa ◽  
M. Jaraíz ◽  
H. J. Gossmann ◽  
G. H. Gilmer ◽  
J. L. Benton ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Kinetic Monte Carlo ◽  
Carbon Diffusion ◽  
Interstitial Concentration ◽  
Carbon Structures ◽  
Kinetic Monte Carlo Simulations ◽  
Equilibrium Concentrations ◽  
Low Solubility ◽  
Carbon Concentrations ◽  
Diffusion Profiles

AbstractA new model for carbon diffusion in silicon that explains carbon diffusion during annealing at 850°C and 900°C in superlattice carbon structures grown by MBE is implemented using the Monte Carlo atomistic simulator DADOS. Carbon concentrations in the delta layers are 2×1020 cm−3, exceeding by far the solid solubility. The simple kick-out mechanism which incorporates the well established values of the product of diffusivity and equilibrium concentrations of intrinsic point defects and in-diffusion experiments of carbon in silicon does not explain the observed C diffusion profiles. A more detailed analysis of the experiments shows that, in order to fit them, a more unstable Ci is required. Therefore, we include the formation of clusters in the simulations. The formation of carbon/Si self-interstitial clusters promotes the premature break-up of Ci and the increase of the Si self-interstitial concentration in the carbon rich regions and, consequently, provides a better fit to the experiments. The low solubility of carbon in silicon at the annealing temperatures explains why these clusters are formed, even under conditions where the self-interstitial concentration is below the equilibrium value.

scholarly journals Temperature Dependent Seed Germination of Dalbergia nigra Allem (Leguminosae)

2001 ◽  
Vol 44 (4) ◽  
pp. 401-404 ◽  
Author(s):  
Fernanda G. A. Ferraz-Grande ◽  
Massanori Takaki
Keyword(s):  
Seed Germination ◽  
Endangered Species ◽  
High Temperatures ◽  
Broad Temperature Range ◽  
Optimum Temperature ◽  
Temperature Dependent ◽  
Temperature Range ◽  
Dalbergia Nigra ◽  
The Mean ◽  
Kinetics Of

The germination of endangered species Dalbergia nigra was studied and 30.5° C was found as optimum temperature, although the species presented a broad temperature range where germination occurs and light had no effect. The analysis of kinetics of seed germination confirmed the asynchronized germination below and above the optimum temperature. The light insensitive seed and germination also at high temperatures indicated that D. nigra could occur both in understories and gaps where the mean temperature was high.

Induction of thermodormancy in Avena sativa seeds

1993 ◽  
Vol 3 (2) ◽  
pp. 111-117 ◽  
Author(s):  
F. Corbineau ◽  
M. Black ◽  
D. Côme
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Avena Sativa ◽  
Inhibitory Action ◽  
Whole Grains ◽  
Temperature Range ◽  
Primary Dormancy

AbstractFreshly harvested oat (Avena sativa L.) seeds are considered to be dormant because they are unable to germinate at relatively high temperatures (above 20°–25°C). This primary dormancy results partly from the structures surrounding or adjacent to the embryo (pericarp, testa and endosperm) and partly lies in the embryo itself. Incubation of imbibed dormant seeds at 30°C induces a thermodormancy which is expressed as germination in a narrower temperature range. Induction of thermodormancy is apparent after 3–8 hours at 30°C, is optimal after about 1–2 days at this temperature, but diminishes with longer treatment times. Although whole grains become more dormant as a result of such treatment, the embryos themselves become less dormant, therefore the tissues covering or adjacent to the embryos must have become more inhibiting or the embryos have become more sensitive to their inhibitory action. The germination and sensitivity to ABA or oxygen of embryos isolated from such seeds are no longer so dependent on temperature. The effect of high temperature on primary dormancy and induction of thermodormancy is discussed with reference to sensitivity to ABA and temperature.

Ti diffusion in feldspar

2020 ◽  
Vol 105 (7) ◽  
pp. 1040-1051
Author(s):  
D. J. Cherniak ◽  
E. B. Watson
Keyword(s):  
Trace Elements ◽  
Silica Glass ◽  
Rutherford Backscattering Spectrometry ◽  
Chemical Diffusion ◽  
Calcic Plagioclase ◽  
Crustal Rocks ◽  
Temperature Range ◽  
Chemical Signatures ◽  
Order Of Magnitude ◽  
Diffusion Profiles

Abstract Chemical diffusion of Ti has been measured in natural K-feldspar and plagioclase. The sources of diffusant used were TiO2 powders or pre-annealed mixtures of TiO2 and Al2O3. Experiments were run in crimped Pt capsules in air or in sealed silica glass capsules with solid buffers (to buffer at NNO). Rutherford backscattering spectrometry (RBS) was used to measure Ti diffusion profiles. From these measurements, the following Arrhenius relations are obtained for diffusion normal to (001):For oligoclase, over the temperature range 750–1050 °C:DOlig=6.67×10-12exp(-207±31kJ/mol/RT)m2s-1For labradorite, over the temperature range 900–1150 °C:DLab=of4.37×10-14exp(-181±57kJ/mol/RT)m2s-1For K-feldspar, over the temperature range 800–1000 °C:DKsp=3.01×10-6exp(-342±47kJ/mol/RT)m2s-1. Diffusivities for experiments buffered at NNO are similar to those run in air, and the presence of hydrous species appears to have little effect on Ti diffusion. Ti diffusion also shows little evidence of anisotropy. In plagioclase, there appears to be a dependence of Ti diffusion on An content of the feldspar, with Ti diffusing more slowly in more calcic plagioclase. This trend is similar to that observed for other cations in plagioclase, including Sr, Pb, Ba, REE, Si, and Mg. In the case of Ti, an increase of 30% in An content would result in an approximate decrease in diffusivity of an order of magnitude. These data indicate that feldspar should be moderately retentive of Ti chemical signatures, depending on feldspar composition. Ti will be more resistant to diffusional alteration than Sr. For example, Ti zoning on a 50 μm scale in oligoclase would be preserved at 600 °C for durations of ~1 million years, with Sr zoning preserved only for ~70 000 yr at this temperature. These new data for a trace impurity that is relatively slow-diffusing and ubiquitous in feldspars (Hoff and Watson 2018) have the potential to extend the scope and applicability of t-T models for crustal rocks based on measurements of trace elements in feldspars.

P1838Thrombocytopenia under ECMO and Shear-induced shedding of platelet receptor Glycoprotein-(GP)Ialpha

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
F Vincent ◽  
A Rauch ◽  
M Desvages ◽  
H Spillemaeker ◽  
N Rousse ◽  
...  
Keyword(s):  
Platelet Count ◽  
Continuous Flow ◽  
High Speed ◽  
Time Dependent ◽  
Loop Model ◽  
High Shear ◽  
Significant Time ◽  
Platelet Receptor ◽  
Flow Device

Abstract Background Several mechanisms are suspected to thrombocytopenia under Extracorporeal Membrane Oxygenation (ECMO) such as platelet-consumption or sepsis. Shedding of glycoprotein-(GP)Ibα is a recently identified mechanism of platelet clearance. ECMO generates high shear stress forces that could impact GPIbα-shedding. We hypothesized that ECMO continuous-flow devices could directly induce thrombocytopenia through shear-induced GPIbα-shedding. Aims Determine if ECMO induce GpIb-shedding in vitro and in vivo and determinates the kinetic evolution of platelet-count and GpIb-shedding after patient's implantation. Methods Platelet GPIbα-shedding was first investigated in vitro using a high-shear pump loop model. Plasma with normal platelet count (plasma-NPC) was obtained by dilution of platelet-rich plasma obtained from healthy donors in fresh-frozen-plasma. Samples were collected before and after (5, 30, 60 and 180 min) perfusion at 37°C of plasma-NPC at intermediate and high speed (2.6 and 3.6 L min–1 respectively, n=4 each). Platelet count and GPIbα-shedding were next investigated in 20 ECMO patients before/after implantation (WITECMO trial) and in 20 healthy volunteers. The geometric mean-fluorescence-intensity (gMFI) of platelet GPIbα (PE-staining) and GPIX (FITC-staining) was measured with a Navios flow cytometer (Beckman Coulter, Miami, FL). Results are expressed as GPIbα/GPIX gMFI-ratio. Results A significant time-dependent loss of GPIbα/GPIX gMFI-ratio was already apparent after 30 min in vitro and was significantly more pronounced at high-speed compared to intermediate-speed (pANOVA<0.001 and p<0.01 at 180 min respectively). GPIbα/GPIX gMFI-ratio was significantly increased in ECMO patients compared to healthy subjects 1- and 24-hour after implantation (p<0.001). A significantly lower platelet count was observed 1 hour after ECMO implantation (−23% vs baseline, p<0.01) with a further significant decrease at 24-hours (−53% vs baseline, p<0.0001). Figure 1. A. Significant time-dependent loss of platelet GPIbα/GPIX gMFI-ratio (pANOVA <0.001) assessed by flow-cytometry after 30 min of perfusion at 3.6 L/min with a high-shear continuous-flow device in vitro. B. Representative experiment showing the apparition of a platelet sub-population with loss of GPIbα expression after 30 min of perfusion at 3.6 L/minwith a high-shear continuous-flow device in vitro.

Sign in / Sign up

Export Citation Format

Share Document