Picosecond Laser Induced Melting: The Dielectric Function of Molten Silicon and Superheating in the Liquid Phase

1988 ◽  
Vol 100 ◽  
Author(s):  
P. M. Fauchet ◽  
K. D. Li
Keyword(s):  
Liquid Phase ◽  
Melting Temperature ◽  
Dielectric Function ◽  
Picosecond Laser ◽  
Computer Code ◽  
Molten Silicon ◽  
Complex Dielectric Function ◽  
Liquid Temperature ◽  
Transient Heating ◽  
Pump And Probe

ABSTRACTThe complex dielectric function of molten silicon produced after picosecond illumination is found to be well described by a Drude model from 1.1 eV to 3.5 eV. Close to the melting temperature, we obtain ωp = 2.50 1016rad/s and τ = 212 10−18s. Transiently, the liquid temperature can exceed the melting temperature or even the boiling temperature Tb. We observe this transient heating and model it with a relatively simple computer code which includes superheating of the liquid above Tb. These measurements are possible thanks to a novel pump and probe technique.

Complex dielectric function and opto-electronic characterization using VEELS for the lead-free BCZT electro-ceramic perovskite

Micron ◽  
2021 ◽  
pp. 103124
Author(s):  
G. Herrera-Perez ◽  
C. Ornelas-Gutierrez ◽  
A. Reyes-Montero ◽  
F. Paraguay-Delgado ◽  
A. Reyes-Rojas ◽  
...  
Keyword(s):  
Dielectric Function ◽  
Lead Free ◽  
Complex Dielectric Function

scholarly journals Breakdown of the Stokes-Einstein relation above the melting temperature in a liquid phase-change material

2018 ◽  
Vol 4 (11) ◽  
pp. eaat8632 ◽  
Author(s):  
Shuai Wei ◽  
Zach Evenson ◽  
Moritz Stolpe ◽  
Pierre Lucas ◽  
C. Austen Angell
Keyword(s):  
Liquid Phase ◽  
Phase Change ◽  
Melting Temperature ◽  
Phase Change Materials ◽  
Dynamic Properties ◽  
Switching Behavior ◽  
Einstein Relation ◽  
Elastic Neutron ◽  
Phase Switching ◽  
Memory Applications

The dynamic properties of liquid phase-change materials (PCMs), such as viscosity η and the atomic self-diffusion coefficientD, play an essential role in the ultrafast phase switching behavior of novel nonvolatile phase-change memory applications. To connect η toD, the Stokes-Einstein relation (SER) is commonly assumed to be valid at high temperatures near or above the melting temperatureTmand is often used for assessing liquid fragility (or crystal growth velocity) of technologically important PCMs. However, using quasi-elastic neutron scattering, we provide experimental evidence for a breakdown of the SER even at temperatures aboveTmin the high–atomic mobility state of a PCM, Ge1Sb2Te4. This implies that although viscosity may have strongly increased during cooling, diffusivity can remain high owing to early decoupling, being a favorable feature for the fast phase switching behavior of the high-fluidity PCM. We discuss the origin of the observation and propose the possible connection to a metal-semiconductor and fragile-strong transition hidden belowTm.

Carbon Capture From Natural Gas via Polymeric Membranes

2018 ◽  
pp. 3043-3055
Author(s):  
Nayef Mohamed Ghasem ◽  
Nihmiya Abdul Rahim ◽  
Mohamed Al-Marzouqi
Keyword(s):  
Liquid Phase ◽  
Low Temperature ◽  
Gas Flow ◽  
Polymeric Membrane ◽  
Co2 Absorption ◽  
Membrane Contactor ◽  
Liquid Temperature ◽  
Liquid Phase Boundary ◽  
Key Factor ◽  
Absorption Performance

Polymeric membrane is a promising energy effective and an active alternative for conventional CO2 absorption column. The type of absorption liquid and operating parameters plays an efficient role in the ultimate absorption/stripping performance using gas-liquid membrane contactor. The gas flow rate has a significant effect on CO2 absorption performance, by contrast, it has no effect on stripping performance. Further the CO2 absorption performance in membrane contactor could be enhanced by high liquid flow rates. Because the gas–liquid contact time was a key factor to enhance the stripping flux at low temperature while liquid phase boundary layer thickness and associated mass transfer resistance is important at elevated temperature. So by controlling the liquid phase velocity and the length of module at low temperature better stripping performance can be achieved. The effect of liquid temperature on absorption performance in gas-liquid is not straightforward, since the liquid temperature cooperatively influence several factors.

A Crucibleless Liquid Phase Growth Method of Preparing the Y‐Ba‐Cu‐0 Superconducting Films

1989 ◽  
Vol 169 ◽  
Author(s):  
K.C. Chen ◽  
L.H. Perng ◽  
C.H. Lin ◽  
T.P. Perng ◽  
T.B. Wu ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Buffer Layer ◽  
Melting Temperature ◽  
Superconducting Films ◽  
Superconducting Transition ◽  
Phase Growth ◽  
Initial Weight ◽  
Growth Method ◽  
Liquid Phase Growth

AbstractSuperconducting Y‐Ba‐Cu‐0 film can be prepared by a liquid phase growth method without crucible on 96 % and 99 % alumina substrates. A buffer layer of sputtered gold or platinum was necessary for the formation of Yba2Cu3Ox phase. The flux of Ba2Cu3O10. was appropriate for this purpose. For a film of 10 mm x 20 mm x 10 micron, 0.6 to 0.8 gm initial weight was optimal, the optimum melting temperature was 1090 to 1110 °C for 20 ‐ 30 minutes. In order to obtain films with superconducting transition, an additional Y2BaCuO5‐underlayer was necessary. The resultant optimal films had Tc‐onset of above 80 % and Tc ‐zero of typically around 60 K.

Influence of Fe2O3 on Molten Slag Properties in Slag Splashing on Nickel Smelting Converter

2011 ◽  
Vol 402 ◽  
pp. 249-252 ◽  
Author(s):  
De Gang Ma ◽  
Wei Qing Chen
Keyword(s):  
Liquid Phase ◽  
Melting Temperature ◽  
Molten Slag ◽  
High Melting ◽  
Melting Points ◽  
Slag Splashing ◽  
Slag Properties ◽  
Factsage Software ◽  
Nickel Smelting ◽  
Slag Column

To predict the effect of Fe2O3 on slag splashing properties in the nickel smelting converter, Factsage software was used to calculate the proportion of the liquid phase and the viscosity for MgO-FeO-Fe2O3-SiO2 melts, the melting temperature was measured using slag column deformation, and the microstructure was also observed. The results show that, when the content of Fe2O3 is increased from 13.79% to 24.14%, the liquid phase at 1250°C maintains a high proportion of 82.68% and the melting temperature is below 1200°C; The magnetite and hortonolite with high melting points are considerably increased, and the viscosity rises accordingly. The melting and viscous properties for the slag with high content of Fe2O3 were improved by adding MgO. Desired slag splashed layer was formed with the saturated Fe2O3 and MgO slag.

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