Metal surface defect formation arising by the laser heating

AbstractDipolar but achiral organic molecules may undergo orientational disorder in the bulk but particularly at the surface of a seed crystal. In cases where the activation energy for reversal of the dipoles in the bulk is much larger than that for reversal at the growing crystal faces, thermodynamic arguments predict that orientational disorder occurring at surface attachment sites can produce metastable but macroscopically large growth sectors, featuring different polar properties than the seed. If the process of nucleation produces a non-pyroelectric symmetry group, then orientational disorder at the surface may give rise to pyroelectric properties during subsequent growth. Similarly, for seeds belonging to a pyroelectric group, orientational disorder can reduce the initial pyroelectric effect. According to this new surface-related mechanism of intrinsic defect formation, acentric and achiral molecules are likely to form real-structures which show a pyroelectric effect, although from a crystallographic point of view, such crystals may be described topologically by e.g. a centric structure. These present views are applied to the space group

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Bubble morphological evolution and surface defect formation mechanism in the microcellular foam injection molding process

RSC Advances ◽

10.1039/c5ra07512b ◽

2015 ◽

Vol 5 (86) ◽

pp. 70032-70050 ◽

Cited By ~ 13

Author(s):

Lei Zhang ◽

Guoqun Zhao ◽

Guiwei Dong ◽

Shuai Li ◽

Guilong Wang

Keyword(s):

Injection Molding ◽

Surface Defect ◽

Defect Formation ◽

Morphological Evolution ◽

Injection Molding Process ◽

Multiphase Model ◽

Microcellular Foam ◽

Molding Process ◽

Foam Injection Molding ◽

Surface Collapse

A multiphase model was established to simulate the bubble morphological evolution in MFIM, and a new phenomenon of surface collapse and pits with the gradient depth was discovered.

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Two Stages of Surface-Defect Formation in a MOS Structure under Low-Dose Rate Gamma Irradiation

Semiconductors ◽

10.1134/s1063782616030209 ◽

2016 ◽

Vol 50 (3) ◽

pp. 349-351 ◽

Cited By ~ 3

Author(s):

V. D. Popov

Keyword(s):

Gamma Irradiation ◽

Dose Rate ◽

Surface Defect ◽

Low Dose ◽

Defect Formation ◽

Mos Structure ◽

Low Dose Rate ◽

Two Stages

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Deposition, Defect and Weak Bond Formation Processes in a-Si:H

MRS Proceedings ◽

10.1557/proc-507-897 ◽

1998 ◽

Vol 507 ◽

Cited By ~ 3

Author(s):

J Robertson ◽

M J Powell

Keyword(s):

Hydrogen Evolution Reaction ◽

Surface Defect ◽

Defect Formation ◽

Defect Density ◽

Bond Formation ◽

Surface Processes ◽

Formation Processes ◽

Weak Bond ◽

Further Development ◽

Surface Defect Density

ABSTRACTThe growth of a-Si:H and the resulting weak bond and defect formation mechanism is analysed in terms of the adsorbed Sill3 model of growth. It is found that this model describes the surface processes well, but it needs further development to correctly describe the temperature dependence of the formation of defects and weak bonds, since the surface defect density decreases monotonically with temperature and does not show a minimum near 250C. We show that the experimentally observed increase in hydrogen content, weak bond and defect density at lower deposition temperatures can be accounted for by a hydrogen evolution reaction from H2* sites.

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