Reactive fluxes delivered by plasma jets to conductive dielectric surfaces during multiple reflections of ionization waves

2020 ◽  
Vol 128 (20) ◽  
pp. 203301
Author(s):  
Natalia Yu. Babaeva ◽  
George V. Naidis
Keyword(s):  
Plasma Jets ◽  
Multiple Reflections ◽  
Dielectric Surfaces ◽  
Ionization Waves

scholarly journals Role of charge accumulation in guided streamer evolution in helium DBD plasma jets

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mikhail Pinchuk ◽  
Anton Nikiforov ◽  
Vadim Snetov ◽  
Zhaoquan Chen ◽  
Christophe Leys ◽  
...  
Keyword(s):  
Duty Cycle ◽  
Strong Field ◽  
Atmospheric Pressure Plasma ◽  
Plasma Jet ◽  
Plasma Jets ◽  
Propagation Mode ◽  
Dbd Plasma ◽  
Duty Cycles ◽  
Ionization Waves

AbstractExperimental data are presented on the evolution of a helium atmospheric pressure plasma jet driven by a tailored voltage waveform generated as bunches of voltage pulses consisting of a superposition of $$\approx 43$$ ≈ 43  kHz bipolar square pulses and $$\approx 300$$ ≈ 300  kHz oscillations. The characteristics of directed ionization waves (guided streamers) are compared for bunches with different first pulse polarities and different bunch duty cycles. The longest and brightest streamers are achieved at the voltage bunch with the first negative pulse and a minimum duty cycle. The dynamics of streamers at the voltage bunch with the first positive pulse are characterized by the shortest length and a lower brightness. The plasma jet length can be smoothly changed by varying the number of pulses in the bunch and the polarity of the first pulse. It is thus possible to precisely localize the region of a strong field in space by combining the parameters of the applied voltage (the duty cycle and polarity of the first pulse of a bunch) with a stepwise propagation mode of a guided streamer.

scholarly journals Ionization waves in nanosecond pulsed atmospheric pressure plasma jets in argon

High Voltage ◽  
2021 ◽  
Author(s):  
Bangdou Huang ◽  
Cheng Zhang ◽  
Wenchao Zhu ◽  
Xinpei Lu ◽  
Tao Shao
Keyword(s):  
Atmospheric Pressure ◽  
Atmospheric Pressure Plasma ◽  
Plasma Jets ◽  
Pressure Plasma ◽  
Ionization Waves

The Impact of Light Polarisation on Light Field of Scenes with Multiple Reflections

2020 ◽  
pp. 108-115 ◽  
Author(s):  
Vladimir P. Budak ◽  
Anton V. Grimaylo
Keyword(s):  
Mathematical Model ◽  
Light Field ◽  
Global Illumination ◽  
Multiple Reflections ◽  
Software Environment ◽  
The Monte Carlo Method ◽  
Mueller Matrices ◽  
Volume Integration ◽  
The Impact

The article describes the role of polarisation in calculation of multiple reflections. A mathematical model of multiple reflections based on the Stokes vector for beam description and Mueller matrices for description of surface properties is presented. On the basis of this model, the global illumination equation is generalised for the polarisation case and is resolved into volume integration. This allows us to obtain an expression for the Monte Carlo method local estimates and to use them for evaluation of light distribution in the scene with consideration of polarisation. The obtained mathematical model was implemented in the software environment using the example of a scene with its surfaces having both diffuse and regular components of reflection. The results presented in the article show that the calculation difference may reach 30 % when polarisation is taken into consideration as compared to standard modelling.

Interactions of Ge Atoms with High- ê Oxide Dielectric Surfaces

2005 ◽  
Vol 879 ◽  
Author(s):  
Scott K. Stanley ◽  
John G. Ekerdt
Keyword(s):  
Oxide Layer ◽  
Photoelectron Spectroscopy ◽  
Chemical Vapor ◽  
Temperature Programmed Desorption ◽  
Tungsten Filament ◽  
X Ray ◽  
Dielectric Surfaces ◽  
Temperature Programmed ◽  
The Stability ◽  
Ge Nanocrystals

AbstractGe is deposited on HfO2 surfaces by chemical vapor deposition (CVD) with GeH4. 0.7-1.0 ML GeHx (x = 0-3) is deposited by thermally cracking GeH4 on a hot tungsten filament. Ge oxidation and bonding are studied at 300-1000 K with X-ray photoelectron spectroscopy (XPS). Ge, GeH, GeO, and GeO2 desorption are measured with temperature programmed desorption (TPD) at 400-1000 K. Ge initially reacts with the dielectric forming an oxide layer followed by Ge deposition and formation of nanocrystals in CVD at 870 K. 0.7-1.0 ML GeHx deposited by cracking rapidly forms a contacting oxide layer on HfO2 that is stable from 300-800 K. Ge is fully removed from the HfO2 surface after annealing to 1000 K. These results help explain the stability of Ge nanocrystals in contact with HfO2.

Microwave Non-Destructive Testing of Coatings and Paints Using Free Space Microwave Measurement

2005 ◽  
Vol 2 (2) ◽  
pp. 17
Author(s):  
Norhayati Hamzah ◽  
Deepak Kumar Ghodgaonkar ◽  
Kamal Faizin Che Kasim ◽  
Zaiki Awang
Keyword(s):  
Free Space ◽  
Protective Coatings ◽  
Microwave Measurement ◽  
Multiple Reflections ◽  
Destructive Testing ◽  
Lens Antennas ◽  
Coatings And Paints ◽  
Microwave Nondestructive Testing ◽  
Mode Transitions ◽  
Diffraction Effects

Microwave nondestructive testing (MNDT) techniques are applied to evaluate quality of anti-corrosive protective coatings and paints on metal surfaces. A tree-space microwave measurement (FSMM) system is used for MNDT of protective coatings. The FSMM system consists of transmit and receive spot-focusing horn lens antennas, a vector network analyzer, mode transitions and a computer. Diffraction effects at the edges of the sample are minimized by using spot-focusing horn lens antennas. Errors due to multiple reflections between antennas are corrected by using free-space LRL (line, reflect, line) calibration technique. We have measured complex reflection coefficient of polyurethane based paint which is coated on brass plates.

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