Faceted crystal growth in two dimensions

Nature ◽  
1991 ◽  
Vol 350 (6316) ◽  
pp. 322-324 ◽  
Author(s):  
Bruno Berge ◽  
Luc Faucheux ◽  
Keith Schwab ◽  
Albert Libchaber
Keyword(s):  
Crystal Growth ◽  
Two Dimensions

Reactive crystal growth in two dimensions: Silicon nitride on Si(111)

1995 ◽  
Vol 51 (24) ◽  
pp. 17891-17901 ◽  
Author(s):  
E. Bauer ◽  
Y. Wei ◽  
T. Müller ◽  
A. Pavlovska ◽  
I. S. T. Tsong
Keyword(s):  
Crystal Growth ◽  
Silicon Nitride ◽  
Two Dimensions

scholarly journals Crystal Growth and the Formation of Spikes in the Surface of Supercooled Water

1960 ◽  
Vol 3 (28) ◽  
pp. 698-704 ◽  
Author(s):  
J. Hallett
Keyword(s):  
Crystal Growth ◽  
Single Crystal ◽  
Composite Structure ◽  
Liquid Surface ◽  
Supercooled Water ◽  
Two Dimensions ◽  
Optic Axis ◽  
Ice Crystals ◽  
Precise Form ◽  
Initial Nucleus

Abstract Observations made of ice crystals growing on the surface of supercooled water show that they take the form of a composite structure, called surface needles, each of which consists of dendrites growing into the liquid, and of ribs growing in the liquid surface. Each needle is a single crystal. The precise form of the needle is determined by the orientation of the initial nucleus. If its optic axis is near normal to the surface, growth occurs rapidly in two dimensions and covers a much larger proportion of the surface than is covered by the narrow surface needles, so that ice forming this way appears to have its optic axis vertical. Hollow ice spikes observed on pools are shown to have been formed by the freezing of water forced from beneath the surface at the intersection of two or three surface needles, the shape of the spike depending on their orientation.

Seven basic regimes of steady crystal growth in two dimensions

1994 ◽  
Vol 77 (1-2) ◽  
pp. 199-215 ◽  
Author(s):  
D. J. Gates ◽  
M. Westcott
Keyword(s):  
Crystal Growth ◽  
Two Dimensions

Graphical modelling of crystal aggregates and its relevance to cement diagnosis

1983 ◽  
Vol 309 (1509) ◽  
pp. 465-502 ◽  
Keyword(s):  
Crystal Growth ◽  
Boundary Migration ◽  
Morphological Type ◽  
Two Dimensions ◽  
Crystallographic Form ◽  
Carbonate Cements ◽  
Graphical Modelling ◽  
Growth Diagram ◽  
Two Generations ◽  
Active Substrate

The identification of carbonate cements in rock sections is accomplished by means of textural criteria. Some of these criteria, relating to crystal fabric, may be modelled graphically in crystal growth diagrams. Existing crystal growth diagrams are oversimplified. Three new crystal growth diagrams are presented for calcite {1011}, {4041} and {0112} rhombohedra The crystals are envisaged as growing by zones of equal width from an inert substrate. The patterns that growth zones create on cuts through individual crystals are used as templates to produce the crystal growth diagrams. 151 crystals seeded on the substrate, on both sides of the crystal growth diagram, are considered to grow at identical rates and impinge on one another. The three crystal growth diagrams illustrate features of crystal initiation and shape in two dimensions not found in previously published diagrams. The rate of maturation of the crystal fabric away from the substrate is shown to depend partly on crystallographic form. Optical elongation is also shown to be related to crystallographic form. The enfacial junction, a special type of triple junction, is shown to be absent from the crystal growth diagrams. The diagrams presented are constrained. Changes in (i) the direction of crystal cutting, (ii) crystallographic form during growth, (iii) the number of crystallographic forms at one time, (iv) the positioning of nuclei, (v) shape of the substrate, and (vi) the change to an active substrate where epitaxy occurs, would all change the character of the crystal growth diagram. The technique of using a list of textural criteria for identifying cements is rejected. Such lists may be used to identify the morphological type of crystal aggregate. After examination of other properties, the decision as to whether that type of aggregate is cement or not can be made. The recognition of impingement growth is made easy if all stages of maturation are present. Where insufficient space is available for mature growth to develop, recognition must rely on features other than textural. A calcite aggregate developed in a Permian bryozoan biolithite is used to illustrate immature impingement growth. This aggregate is identified as of impingement type principally from the arrangement of growth zonation shown in each crystal by cathodoluminescence. The enfacial junction, often regarded as the least equivocal criterion for the recognition of cements, is absent from the crystal growth diagrams and the Permian biolithite. The origin of enfacial junctions in a Lower Carboniferous spar is thought to be due either to unusual sporadic growth inhibition or, more likely, to intercrystalline boundary migration due to dissolution. Enfacial junctions are common in ancient spars: if generated by intercrystalline dissolution considerable quantities of CaCO 3 have been liberated. Enfacial junctions also develop at the junction of two generations of crystals not exhibiting epitaxy.

scholarly journals Crystal Growth and the Formation of Spikes in the Surface of Supercooled Water

1960 ◽  
Vol 3 (28) ◽  
pp. 698-704 ◽  
Author(s):  
J. Hallett
Keyword(s):  
Crystal Growth ◽  
Single Crystal ◽  
Composite Structure ◽  
Liquid Surface ◽  
Supercooled Water ◽  
Two Dimensions ◽  
Optic Axis ◽  
Ice Crystals ◽  
Precise Form ◽  
Initial Nucleus

AbstractObservations made of ice crystals growing on the surface of supercooled water show that they take the form of a composite structure, called surface needles, each of which consists of dendrites growing into the liquid, and of ribs growing in the liquid surface. Each needle is a single crystal. The precise form of the needle is determined by the orientation of the initial nucleus. If its optic axis is near normal to the surface, growth occurs rapidly in two dimensions and covers a much larger proportion of the surface than is covered by the narrow surface needles, so that ice forming this way appears to have its optic axis vertical. Hollow ice spikes observed on pools are shown to have been formed by the freezing of water forced from beneath the surface at the intersection of two or three surface needles, the shape of the spike depending on their orientation.

scholarly journals Bridgman Crystal Growth of an Alloy With Thermosolutal Convection Under Microgravity Conditions

2001 ◽  
Vol 123 (5) ◽  
pp. 990-998 ◽  
Author(s):  
James E. Simpson ◽  
Suresh V. Garimella ◽  
Henry C. de Groh ◽  
Reza Abbaschian
Keyword(s):  
Crystal Growth ◽  
Growth Conditions ◽  
Convective Cell ◽  
Two Dimensions ◽  
Experimental Results ◽  
Thermosolutal Convection ◽  
Microgravity Environment ◽  
Uniform Grid ◽  
Microgravity Conditions ◽  
Bridgman Crystal Growth

The solidification of a dilute alloy (bismuth-tin) under Bridgman crystal growth conditions is investigated. Computations are performed in two dimensions with a uniform grid. The simulation includes the species concentration, temperature and flow fields, as well as conduction in the ampoule. Fully transient simulations have been performed, with no simplifying steady state approximations. Results are obtained under microgravity conditions for pure bismuth, and for Bi-0.1 at.% Sn and Bi-1.0 at.% Sn alloys, and compared with experimental results obtained from crystals grown in the microgravity environment of space. For the Bi-1.0 at.% Sn case the results indicate that a secondary convective cell, driven by solutal gradients, forms near the interface. The magnitude of the velocities in this cell increases with time, causing increasing solute segregation at the solid/liquid interface. Finally, a comparison between model predictions and results obtained from a space experiment is reported. The concentration-dependence of the alloy melting temperature is incorporated in the model for this case. Satisfactory correspondence is obtained between the predicted and experimental results in terms of solute concentrations in the solidified crystal.

A 3-D crystal growth-disorder model with cubic symmetry

1979 ◽  
Vol 367 (1729) ◽  
pp. 175-192 ◽  
Keyword(s):  
Crystal Growth ◽  
Three Dimensional ◽  
Two Dimensions ◽  
Nearest Neighbour ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Cubic Symmetry ◽  
One Dimensional ◽  
Growth Disorder

A three-dimensional model of crystal growth-disorder is described. It is shown that imposition of m 3 m symmetry on the model results in the same reduction to essentially one dimensional properties, as occurs in pre­viously described work in two dimensions. The probability parameter space is subject to more stringent restrictions than for the corresponding two dimensional model and only realizations with nearest-neighbour two-point correlations less than √2 -1 can occur. For zero two-point corre­lation a considerable degree of variation in multi-point properties is possible. The three-dimensional distributions are shown to have Markov chains embedded in them.

The tangled web of agency

2018 ◽  
Vol 41 ◽  
Author(s):  
Alain Pe-Curto ◽  
Julien A. Deonna ◽  
David Sander
Keyword(s):  
Two Dimensions ◽  
Bad Company

AbstractWe characterize Doris's anti-reflectivist, collaborativist, valuational theory along two dimensions. The first dimension is socialentanglement, according to which cognition, agency, and selves are socially embedded. The second dimension isdisentanglement, the valuational element of the theory that licenses the anchoring of agency and responsibility in distinct actors. We then present an issue for the account: theproblem of bad company.

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