Equilibrium position of misfit dislocation dipole and critical parameters of buried strained nanoscale inhomogeneity in system of viscoelastic matrix

In polyethylene single crystals pairs of black and white lines spaced 700-3,000Å apart, parallel to the [100] and [010] directions, have been identified as microsector boundaries. A microsector is formed when the plane of chain folding changes over a small distance within a polymer crystal. In order for the different types of folds to accommodate at the boundary between the 2 fold domains, a staggering along the chain direction and a rotation of the chains in the plane of the boundary occurs. The black-white contrast from a microsector boundary can be explained in terms of these chain rotations. We demonstrate that microsectors can terminate within the crystal and interpret the observed terminal strain contrast in terms of a screw dislocation dipole model.

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Formation of Persistent Slip Band in Fatigued Copper Single Crystals

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100054807 ◽

1982 ◽

Vol 40 ◽

pp. 470-471

Author(s):

N. Y. Jin

Keyword(s):

Volume Fraction ◽

Fatigue Cracks ◽

Wall Structure ◽

Matrix Structure ◽

Dislocation Dipole ◽

Slip Bands ◽

Persistent Slip Bands ◽

The Matrix ◽

Hard Shell ◽

Copper Single Crystals

Localised plastic deformation in Persistent Slip Bands(PSBs) is a characteristic feature of fatigue in many materials. The dislocation structure in the PSBs contains regularly spaced dislocation dipole walls occupying a volume fraction of around 10%. The remainder of the specimen, the inactive "matrix", contains dislocation veins at a volume fraction of 50% or more. Walls and veins are both separated by regions in which the dislocation density is lower by some orders of magnitude. Since the PSBs offer favorable sites for the initiation of fatigue cracks, the formation of the PSB wall structure is of great interest. Winter has proposed that PSBs form as the result of a transformation of the matrix structure to a regular wall structure, and that the instability occurs among the broad dipoles near the center of a vein rather than in the hard shell surounding the vein as argued by Kulmann-Wilsdorf.

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Misfit Dislocations in the Ilmenite (FeTiO3)-Hematite (Fe2O3) System

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600000921 ◽

1980 ◽

Vol 38 ◽

pp. 212-213 ◽

Cited By ~ 1

Author(s):

K.P.D. Lagerlöf ◽

A.H. Heuer ◽

T.E. Mitchell

Keyword(s):

Misfit Dislocation ◽

Lattice Parameters ◽

Dislocation Network ◽

Misfit Dislocations ◽

Space Group ◽

Two Phases ◽

Hematite Fe2o3

It has been reported by Lally et. al. [1] that precipitates of hematite (Fe2O3, space group R3c) in a matrix of ilmenite (FeTiO3, space group R3) are lens shaped and flattened along the [0001]-direction. The coherency across the interface is lost by the introduction of a misfit dislocation network, which minimizes the strain due to the deviation in lattice parameters between the two phases [2]. The purpose of this paper is to present a new analysis of this network.

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Multi-layer Tablets: Study of the Critical Parameters by a Compression Simulator

10.26226/morressier.57d6b2bdd462b8028d88db27 ◽

2016 ◽

Author(s):

Alessandra Rossi

Keyword(s):

Critical Parameters

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New Insights into the Nature of the Band Gap of CuGeO3 Nanoparticles: Synthesis, Electronic Structure, and Optical and Photocatalytic Properties

10.26434/chemrxiv.8362409.v1 ◽

2019 ◽

Author(s):

Victor Y. Suzuki ◽

Luís Henrique Cardozo Amorin ◽

Natália H. de Paula ◽

Anderson R. Albuquerque ◽

Julio Ricardo Sambrano ◽

...

Keyword(s):

Electronic Structure ◽

Band Gap ◽

Material Design ◽

Photocatalytic Properties ◽

Critical Parameters ◽

Synthetic Approach ◽

Microwave Assisted ◽

Theoretical Approaches ◽

Nanoparticles Synthesis ◽

First Time

We report, for the first time, new insights into the nature of the band gap of <a>CuGeO3 </a>(CGO) nanocrystals synthesized from a microwave-assisted hydrothermal method in the presence of citrate. To the best of our knowledge, this synthetic approach has the shortest reaction time and it works at the lowest temperatures reported in the literature for the preparation of these materials. The influence of the surfactant on the structural, electronic, optical, and photocatalytic properties of CGO nanocrystals is discussed by a combination of experimental and theoretical approaches, and that results elucidates the nature of the band gap of synthetized CGO nanocrystals. We believe that this particular strategy is one of the most critical parameters for the development of innovative applications and that result could shed some light on the emerging material design with entirely new properties.

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