Direct Measurement of Crystal Nucleation and Growth Rate Kinetics in Backmixed Crystal Slurry. Study of the K2SO4System

1970 ◽  
Vol 9 (1) ◽  
pp. 165-171 ◽  
Author(s):  
A. D. Randolph ◽  
Krishnaswami Rajagopal
Keyword(s):  
Growth Rate ◽  
Direct Measurement ◽  
Nucleation And Growth ◽  
Crystal Nucleation ◽  
Rate Kinetics

Nucleation And Growth Rates in Isothermal Crystallization Op Amorphous Si50Ge50 Films

1993 ◽  
Vol 321 ◽  
Author(s):  
J. H. Song ◽  
James S. Im
Keyword(s):  
Growth Rate ◽  
Nucleation Rate ◽  
Growth Rates ◽  
Isothermal Crystallization ◽  
Nucleation And Growth ◽  
Crystal Nucleation ◽  
Two Dimensional ◽  
Transmission Electron ◽  
Amorphous Si ◽  
Si Films

ABSTRACTIsothermal crystallization behavior of as-deposited thin amorphous Si50Ge50 films (∼1000Å-thick) at 580°C has been investigated using transmission electron Microscopy (TEM). The crystal counting method was employed in order to obtain directly the two-dimensional steady-state crystal nucleation rate of 3.9×103 #/cm2sec (equivalent volumetric nucleation rate of 3.4×108 #/cm3sec). The Modified two-dimensional Johnson-Mehl-Avrami analysis, in which the growth rate of the crystals was the only adjustable parameter, and in which the time-dependent nucleation rate and the size effect associated with the onset of the observation are considered, was developed in order to extract the crystal growth rate of 16.5 Å/sec. When compared to the crystallization of a-Si films, these nucleation and growth rates confirm the observation that it is possible to achieve significantly faster crystallization at lower temperatures while producing substantially better Microstructures (i.e., > 5 μ grain-sized poly-Si50Ge50 obtained within two hours at 580°C vs. 1–2Μm grain-sized poly-Si obtained in about > 10 hours at 600°C).

scholarly journals Molecular Dynamics Simulations of Crystal Nucleation near Interfaces in Incompatible Polymer Blends

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 347
Author(s):  
Wenlin Zhang ◽  
Lingyi Zou
Keyword(s):  
Molecular Dynamics ◽  
Polymer Blends ◽  
Md Simulations ◽  
Nucleation And Growth ◽  
Crystal Nucleation ◽  
Crystalline Order ◽  
Mobile Species ◽  
Deep Supercooling ◽  
Crystallizable Polymer ◽  
Dynamics Simulations

We apply molecular dynamics (MD) simulations to investigate crystal nucleation in incompatible polymer blends under deep supercooling conditions. Simulations of isothermal nucleation are performed for phase-separated blends with different degrees of incompatibility. In weakly segregated blends, slow and incompatible chains in crystallizable polymer domains can significantly hinder the crystal nucleation and growth. When a crystallizable polymer is blended with a more mobile species in interfacial regions, enhanced molecular mobility leads to the fast growth of crystalline order. However, the incubation time remains the same as that in pure samples. By inducing anisotropic alignment near the interfaces of strongly segregated blends, phase separation also promotes crystalline order to grow near interfaces between different polymer domains.

Phase separation in undercooled molten Pd80Si20: Part I

1999 ◽  
Vol 14 (9) ◽  
pp. 3653-3662 ◽  
Author(s):  
K. L. Lee ◽  
H. W. Kui
Keyword(s):  
Growth Rate ◽  
Phase Separation ◽  
Crystal Growth ◽  
Grain Refinement ◽  
Crystallization Temperature ◽  
Sharp Decrease ◽  
Nucleation And Growth ◽  
Crystal Growth Rate ◽  
Large Undercooling ◽  
Kinetic Crystallization

Three different kinds of morphology are found in undercooled Pd80Si20, and they dominate at different undercooling regimens ΔT, defined as ΔT = T1 – Tk, where T1 is the liquidus of Pd80Si20 and Tk is the kinetic crystallization temperature. In the small undercooling regimen, i.e., for ΔT ≤ 190 K, the microstructures are typically dendritic precipitation with a eutecticlike background. In the intermediate undercooling regimen, i.e., for 190 ≤ ΔT ≤ 220 K, spherical morphologies, which arise from nucleation and growth, are identified. In addition, Pd particles are found throughout an entire undercooled specimen. In the large undercooling regimen, i.e., for ΔT ≥ 220 K, a connected structure composed of two subnetworks is found. A sharp decrease in the dimension of the microstructures occurs from the intermediate to the large undercooling regimen. Although the crystalline phases in the intermediate and the large undercooling regimens are the same, the crystal growth rate is too slow to bring about the occurrence of grain refinement. Combining the morphologies observed in the three undercooling regimens and their crystallization behaviors, we conclude that phase separation takes place in undercooled molten Pd80Si20.

Direct Measurement of Nucleation and Growth Modes in Titania Nanoparticles Generation by a CVD Method

2004 ◽  
Vol 37 (11) ◽  
pp. 1379-1389 ◽  
Author(s):  
Chan Soo Kim ◽  
Kikuo Okuyama ◽  
Koichi Nakaso ◽  
Manabu Shimada
Keyword(s):  
Direct Measurement ◽  
Nucleation And Growth ◽  
Titania Nanoparticles ◽  
Cvd Method ◽  
Growth Modes

scholarly journals Crystal nucleation and growth kinetics of NaF in photo-thermo-refractive glass

2013 ◽  
Vol 378 ◽  
pp. 115-120 ◽  
Author(s):  
I. Dyamant ◽  
A.S. Abyzov ◽  
V.M. Fokin ◽  
E.D. Zanotto ◽  
J. Lumeau ◽  
...  
Keyword(s):  
Growth Kinetics ◽  
Nucleation And Growth ◽  
Crystal Nucleation ◽  
Kinetics Of

Membrane-protein crystals for neutron diffraction

2018 ◽  
Vol 74 (12) ◽  
pp. 1208-1218 ◽  
Author(s):  
Thomas Lykke-Møller Sørensen ◽  
Samuel John Hjorth-Jensen ◽  
Esko Oksanen ◽  
Jacob Lauwring Andersen ◽  
Claus Olesen ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Neutron Diffraction ◽  
Membrane Protein ◽  
Neutron Source ◽  
Nucleation And Growth ◽  
Crystal Nucleation ◽  
Protein Crystals ◽  
Macromolecular Crystallography ◽  
Transport Mechanisms ◽  
Potential Impact

Neutron macromolecular crystallography (NMX) has the potential to provide the experimental input to address unresolved aspects of transport mechanisms and protonation in membrane proteins. However, despite this clear scientific motivation, the practical challenges of obtaining crystals that are large enough to make NMX feasible have so far been prohibitive. Here, the potential impact on feasibility of a more powerful neutron source is reviewed and a strategy for obtaining larger crystals is formulated, exemplified by the calcium-transporting ATPase SERCA1. The challenges encountered at the various steps in the process from crystal nucleation and growth to crystal mounting are explored, and it is demonstrated that NMX-compatible membrane-protein crystals can indeed be obtained.

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