Dislocation Walls in Finite Media: The Case of an Infinite Slab

ABSTRACTThe dislocation microstructure observed in solids exhibits cellular patterns. The interiors of these cells are depleted of dislocations while the walls contain dense bundles including the geometrically necessary dislocations leading to misorientations of the crystal lattice on either side. This clustering is the result of short-range interactions which favor the formation of dislocation dipoles or multipoles and tilt and twist boundaries. While this short-range ordering of dislocations is readily understood, the long-range pattern formation is still being studied. We examine finite tilt boundaries in an infinite medium, a model grain, and a free slab to investigate the conditions for long-range stress interactions. We find that finite tilt walls in a larger medium generally possess a long-range stress field because the local bending at the tilt wall is constrained by the surrounding material.

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Long-range and short-range ordering in 2D honeycomb-lattice magnet Na2Ni2TeO6

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2019.153354 ◽

2020 ◽

Vol 820 ◽

pp. 153354

Author(s):

Alexander I. Kurbakov ◽

Artem N. Korshunov ◽

Stanislav Yu Podchezertsev ◽

Mikhail I. Stratan ◽

Grigory V. Raganyan ◽

...

Keyword(s):

Long Range ◽

Short Range ◽

Honeycomb Lattice ◽

Short Range Ordering

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Relation of Long-Range Interatomic Interactions to the Sign and Type of Short-Range Ordering in Alloys

physica status solidi (b) ◽

10.1002/pssb.2220510204 ◽

1972 ◽

Vol 51 (2) ◽

pp. 457-461 ◽

Cited By ~ 7

Author(s):

A. A. Katsnelson

Keyword(s):

Long Range ◽

Short Range ◽

Short Range Ordering

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Nanoscale Pattern Formation in Polyelectrolyte Gels

MRS Proceedings ◽

10.1557/proc-1234-qq02-07 ◽

2009 ◽

Vol 1234 ◽

Author(s):

Prateek K. Jha ◽

Francisco J. Solis ◽

Juan J. de Pablo ◽

Monica Olvera de la Cruz

Keyword(s):

Pattern Formation ◽

Phase Behavior ◽

Long Range ◽

Short Range ◽

Physical Parameters ◽

Finite Range ◽

Complex Phase ◽

One Dimensional ◽

Polyelectrolyte Gels ◽

Poor Solvent

AbstractPolyelectrolyte (PE) gels exhibit complex phase behavior that includes the existence of nanostructures in poor-solvent conditions. The formation of these inhomogeneous structures is made possible by the competition between the short-range hydrophobic, elastic, and entropic interactions and the long-range electrostatic forces. We develop a theoretical framework that describes the effect of monomer and charge inhomogeneities in PE gels. Numerical calculations performed on a salt-free PE gel with one-dimensional heterogeneities demonstrate the presence of nanophases for a finite range of physical parameters.

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Long-range vs. short-range ordering in synthetic Cr-substituted goethites

Geochimica et Cosmochimica Acta ◽

10.1016/j.gca.2004.01.017 ◽

2004 ◽

Vol 68 (14) ◽

pp. 3053-3063 ◽

Cited By ~ 24

Author(s):

Elsa E Sileo ◽

Aline Y Ramos ◽

Graciela E Magaz ◽

Miguel A Blesa

Keyword(s):

Long Range ◽

Short Range ◽

Short Range Ordering

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Pattern formation and self-assembly driven by competing interactions

Soft Matter ◽

10.1039/c7sm02125a ◽

2017 ◽

Vol 13 (48) ◽

pp. 9259-9272 ◽

Cited By ~ 16

Author(s):

Davide Pini ◽

Alberto Parola

Keyword(s):

Pattern Formation ◽

Long Range ◽

Self Assembly ◽

Short Range ◽

Competing Interactions ◽

Effective Potentials ◽

Simple Mechanism ◽

Colloidal Fluids

Colloidal fluids interacting via effective potentials which are attractive at the short range and repulsive at the long range have long been raising considerable attention because such an instance provides a simple mechanism leading to pattern formation even for isotropic interactions.

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Long-range and short-range ordering of hydrogen or deuterium atoms in solid solution in yttrium

Journal of the Less Common Metals ◽

10.1016/0022-5088(87)90063-4 ◽

1987 ◽

Vol 129 ◽

pp. 287-295 ◽

Cited By ~ 27

Author(s):

J.E. Bonnet ◽

D.K. Ross ◽

D.A. Faux ◽

I.S. Anderson

Keyword(s):

Solid Solution ◽

Long Range ◽

Short Range ◽

Short Range Ordering

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Spontaneous Lateral Composition Modulation in III-V Semiconductor Alloys

MRS Bulletin ◽

10.1557/s088376940003339x ◽

1997 ◽

Vol 22 (7) ◽

pp. 38-43 ◽

Cited By ~ 38

Author(s):

J. Mirecki Millunchick ◽

R.D. Twesten ◽

S.R. Lee ◽

D.M. Follstaedt ◽

E.D. Jones ◽

...

Keyword(s):

Long Range ◽

High Speed ◽

Short Range ◽

Carrier Mobility ◽

Alloy System ◽

Semiconductor Alloys ◽

Chemical Ordering ◽

Short Range Ordering ◽

Device Structures ◽

Long Range Ordering

The application of III-V semiconductor alloys in device structures is of importance for high-speed microelectronics and optoelectronics. These alloys have allowed the device engineer to tailor material parameters such as the bandgap and carrier mobility to the need of the device by altering the alloy composition. When using ternary or quaternary materials, the device designer presumes that the alloy is completely disordered, without any correlation between the atoms on the cation (anion) sublattice. However the thermodynamics of the alloy system often produce material that has some degree of macroscopic or microscopic ordering. Short-range ordering occurs when atoms adopt correlated neighboring positions over distances of the order of a few lattice spacings. This can be manifested as the preferential association of like atoms, as in clustering, or of unlike atoms, as in chemical ordering (e.g., CuPt ordering). Long-range ordering occurs over many tens of lattice spacings, as in the case of phase separation. In either short-range or long-range ordering, the band structure and the crystal symmetry are greatly altered. Therefore it is absolutely critical that the mechanisms be fully understood to prevent ordering when necessary or to exploit it when possible.

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Synthetic mammalian pattern formation driven by differential diffusivity of Nodal and Lefty

10.1101/372490 ◽

2018 ◽

Author(s):

Ryoji Sekine ◽

Tatsuo Shibata ◽

Miki Ebisuya

Keyword(s):

Pattern Formation ◽

Long Range ◽

Mammalian Cells ◽

Short Range ◽

Mammalian Cell Culture ◽

Reaction Diffusion ◽

Minimal Network ◽

Range Distribution ◽

Domain Structures ◽

Diffusion Pattern

AbstractPattern formation is fundamental for embryonic development. Although synthetic biologists have created several patterns, a synthetic mammalian reaction-diffusion pattern has yet to be realized. TGF-β family proteins Nodal and Lefty have been proposed to meet the conditions for reaction-diffusion patterning: Nodal is a short-range activator that enhances the expression of Nodal and Lefty whereas Lefty acts as a long-range inhibitor against Nodal. However, the pattern forming possibility of the Nodal-Lefty signaling has never been directly tested, and the underlying mechanisms of differential diffusivity of Nodal and Lefty remain unclear. Here, through a combination of synthetic biology and theoretical modeling, we show that a reconstituted minimal network of the Nodal-Lefty signaling spontaneously gives rise to a pattern in mammalian cell culture. Surprisingly, extracellular Nodal was confined underneath the cells as small clusters, resulting in a narrow distribution range compared with Lefty. We further found that the finger 1 domain of the Nodal protein is responsible for its short-range distribution. By transplanting the finger 1 domain of Nodal into Lefty, we converted the originally long-range distribution of Lefty to a short-range one, successfully preventing the pattern formation. These results indicate that the differences in the localization and domain structures between Nodal and Lefty, combined with the activator-inhibitor topology, are sufficient for reaction-diffusion pattern formation in mammalian cells.

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TEM Study of a Tilt Boundary in Hot-Pressed Silicon

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100097454 ◽

1981 ◽

Vol 39 ◽

pp. 160-161

Author(s):

C. B. Carter ◽

J. Rose ◽

D. G. Ast

Keyword(s):

Electron Diffraction ◽

Imaging Technique ◽

Interface Structure ◽

Large Area ◽

Weak Beam ◽

Lattice Fringe ◽

Electron Diffraction Technique ◽

Tilt Boundaries ◽

Beam Technique ◽

Twist Boundaries

The hot-pressing technique which has been successfully used to manufacture twist boundaries in silicon has now been used to form tilt boundaries in this material. In the present study, weak-beam imaging, lattice-fringe imaging and electron diffraction techniques have been combined to identify different features of the interface structure. The weak-beam technique gives an overall picture of the geometry of the boundary and in particular allows steps in the plane of the boundary which are normal to the dislocation lines to be identified. It also allows pockets of amorphous SiO2 remaining in the interface to be recognized. The lattice-fringe imaging technique allows the boundary plane parallel to the dislocation to be identified. Finally the electron diffraction technique allows the periodic structure of the boundary to be evaluated over a large area - this is particularly valuable when the dislocations are closely spaced - and can also provide information on the structural width of the interface.

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High-resolution x-ray analysis of dislocation networks nn tilt boundaries

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100105126 ◽

1988 ◽

Vol 46 ◽

pp. 612-613

Author(s):

J. R. Michael ◽

C. H. Lin ◽

S. L. Sass

Keyword(s):

Grain Boundaries ◽

Analytical Electron Microscopy ◽

Solute Segregation ◽

X Ray ◽

Periodic Arrays ◽

Analytical Electron ◽

Primary Dislocation ◽

Tilt Boundaries ◽

Polycrystalline Solids ◽

Twist Boundaries

The segregation of solute atoms to grain boundaries in polycrystalline solids can be responsible for embrittlement of the grain boundaries. Although Auger electron spectroscopy (AES) and analytical electron microscopy (AEM) have verified the occurrence of solute segregation to grain boundaries, there has been little experimental evidence concerning the distribution of the solute within the plane of the interface. Sickafus and Sass showed that Au segregation causes a change in the primary dislocation structure of small angle [001] twist boundaries in Fe. The bicrystal specimens used in their work, which contain periodic arrays of dislocations to which Au is segregated, provide an excellent opportunity to study the distribution of Au within the boundary by AEM.The thin film Fe-0.8 at% Au bicrystals (composition determined by Rutherford backscattering spectroscopy), ∼60 nm thick, containing [001] twist boundaries were prepared as described previously. The bicrystals were analyzed in a Vacuum Generators HB-501 AEM with a field emission electron source and a Link Analytical windowless x-ray detector.

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