Pimples reduce and dimples enhance flat dielectric surface image repulsion

Electron microdiffraction patterns, obtained when a small electron probe with diameter of 10-15 Å is directed to run parallel to and outside a flat crystal surface, are sensitive to the surface nature of the crystals. Dynamical diffraction calculations have shown that most of the experimental observations for a flat (100) face of a MgO crystal, such as the streaking of the central spot in the surface normal direction and (100)-type forbidden reflections etc., could be explained satisfactorily by assuming a modified image potential field outside the crystal surface. However the origin of this extended surface potential remains uncertain. A theoretical analysis by Howie et al suggests that the surface image potential should have a form different from above-mentioned image potential and also be smaller by several orders of magnitude. Nevertheless the surface potential distribution may in practice be modified in various ways, such as by the adsorption of a monolayer of gas molecules.

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Spark Discharge over the Solid Dielectric Surface in Vacuum

Elektrichestvo ◽

10.24160/0013-5380-2018-7-31-36 ◽

2018 ◽

Vol 7 (7) ◽

pp. 31-36

Author(s):

Vyacheslav I. ASYUNIN ◽

◽

Sergei G. DAVYDOV ◽

Alexander N. DOLGOV ◽

Andrei V. KORNEYEV ◽

...

Keyword(s):

Dielectric Surface ◽

Spark Discharge ◽

Solid Dielectric

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Evaluation of Far Infrared Camera for Surface Image Velocimeter Versatile in Day and Night Measurement

Journal of Korea Water Resources Association ◽

10.3741/jkwra.2015.48.8.659 ◽

2015 ◽

Vol 48 (8) ◽

pp. 659-672 ◽

Cited By ~ 2

Author(s):

Yu Kwonkyu ◽

◽

Kim Seojun ◽

Yoo Byeongnam ◽

Bae Inhyuk

Keyword(s):

Infrared Camera ◽

Far Infrared ◽

Surface Image

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Development of a real-time surface image velocimeter using an android smartphone

Journal of Korea Water Resources Association ◽

10.3741/jkwra.2016.49.6.469 ◽

2016 ◽

Vol 49 (6) ◽

pp. 469-480

Author(s):

Kwonkyu Yu ◽

Jeong-Geun Hwang

Keyword(s):

Real Time ◽

Surface Image

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Autonomous Crack and Bughole Detection for Concrete Surface Image Based on Deep Learning

IEEE Access ◽

10.1109/access.2021.3088292 ◽

2021 ◽

pp. 1-1

Author(s):

Yujia Sun ◽

Yang Yang ◽

Gang Yao ◽

Fujia Wei ◽

Mingpu Wong

Keyword(s):

Deep Learning ◽

Concrete Surface ◽

Surface Image

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Experimental and Simulation Investigation of the Nanoscale Charge Diffusion Process on a Dielectric Surface: Effects of Relative Humidity

The Journal of Physical Chemistry C ◽

10.1021/acs.jpcc.1c02272 ◽

2021 ◽

Author(s):

Xuejie Bai ◽

Adriaan Riet ◽

Song Xu ◽

Daniel J. Lacks ◽

Haifeng Wang

Keyword(s):

Relative Humidity ◽

Diffusion Process ◽

Surface Effects ◽

Dielectric Surface

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Current Filaments in Asymmetric Surface Dielectric Barrier Discharge

Applied Sciences ◽

10.3390/app11052079 ◽

2021 ◽

Vol 11 (5) ◽

pp. 2079

Author(s):

Cecilia Piferi ◽

Ruggero Barni ◽

H. Eduardo Roman ◽

Claudia Riccardi

Keyword(s):

Electromagnetic Waves ◽

Dielectric Surface ◽

Half Cycle ◽

Dielectric Barrier Discharges ◽

Time Duration ◽

Lower Electrode ◽

Dielectric Barrier ◽

Forward Stroke ◽

Mean Charge ◽

Mean Current

In this study, we examine the statistical properties of asymmetric surface dielectric barrier discharges (SDBD) produced by applying a periodic high voltage between two conducting displaced electrodes, located at the opposite sides of a flat dielectric panel. Here, the asymmetry refers to the fact that the lower electrode is fully covered with an insulating material, while the upper one, glued onto the dielectric surface, is otherwise left exposed to the air. Such a configuration allows the formation of a thin layer of plasma above the insulating surface. A single cycle signal consists of two well-separated half-cycle patterns, denoted as forward and backward strokes, corresponding to positive and negative voltages, respectively. They display a quite complex discharge pattern constituted by a sequence of individual peaks (bursts) of varying current and time duration. Specifically, we find that backward stroke bursts carry a positive mean charge Q≃0.3 nC and mean current I≃35 mA, with a mean duration τ≃15 ns, while forward stroke bursts have a negative mean charge Q≃−0.1 nC, a mean current I≃−20 mA, and a mean duration τ≃11 ns. The statistical analysis suggests that power injection can be tailored to produce the active agents in the plasma needed for a particular application. We also determined discharge spatial correlation patterns from measurements of the associated stimulated optical emission. The optical excitations occur as a result of the ionizing effect of the electromagnetic waves which ignite the discharge, followed by the electric current flow. In particular, we point out that one of the phases of the discharge is compatible with a cathode directed streamer phenomenon (backward stroke), while the mechanism acting for a forward stroke has a different structure.

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