ELECTRICAL BREAKDOWN IN XENON AND KRYPTON AT ULTRAHIGH FREQUENCIES

1959 ◽  
Vol 37 (10) ◽  
pp. 1166-1170 ◽  
Author(s):  
H. M. Bradford ◽  
D. M. Fraser ◽  
G. F. O. Langstroth ◽  
A. D. MacDonald
Keyword(s):  
Electric Fields ◽  
Pressure Range ◽  
Electrical Breakdown ◽  
Resonant Cavity ◽  
Ultrahigh Frequencies

Breakdown electric fields have been measured in a resonant cavity for xenon and krypton gases in the pressure range of 0.05 to 100 mm of mercury, at a frequency of 2800 Mc/sec. Extensive precautions were taken to ensure gas purity.

ELECTRICAL BREAKDOWN IN ARGON AT ULTRAHIGH FREQUENCIES

1956 ◽  
Vol 34 (4) ◽  
pp. 395-397 ◽  
Author(s):  
A. D. MacDonald ◽  
J. H. Matthews
Keyword(s):  
Electric Fields ◽  
Electrical Breakdown ◽  
Resonant Cavities ◽  
Argon Gas ◽  
Pure Argon ◽  
Ultrahigh Frequencies ◽  
Made In

Measured values of breakdown electric fields in pure argon gas are presented. Measurements were made in two resonant cavities at a frequency of 2800 Mc./sec. and for pressures varying from 4 × 10−2 to 200 mm. of mercury. The present results are in agreement with those of Krasik, Alpert, and McCoubrey.

scholarly journals Electrical tunability of terahertz nonlinearity in graphene

2021 ◽  
Vol 7 (15) ◽  
pp. eabf9809
Author(s):  
Sergey Kovalev ◽  
Hassan A. Hafez ◽  
Klaas-Jan Tielrooij ◽  
Jan-Christoph Deinert ◽  
Igor Ilyakov ◽  
...  
Keyword(s):  
Electric Fields ◽  
Quantitative Agreement ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Single Cycle ◽  
Terahertz Frequency Range ◽  
Third Harmonic ◽  
Accurate Design ◽  
Electronic Signal Processing ◽  
Ultrahigh Frequencies

Graphene is conceivably the most nonlinear optoelectronic material we know. Its nonlinear optical coefficients in the terahertz frequency range surpass those of other materials by many orders of magnitude. Here, we show that the terahertz nonlinearity of graphene, both for ultrashort single-cycle and quasi-monochromatic multicycle input terahertz signals, can be efficiently controlled using electrical gating, with gating voltages as low as a few volts. For example, optimal electrical gating enhances the power conversion efficiency in terahertz third-harmonic generation in graphene by about two orders of magnitude. Our experimental results are in quantitative agreement with a physical model of the graphene nonlinearity, describing the time-dependent thermodynamic balance maintained within the electronic population of graphene during interaction with ultrafast electric fields. Our results can serve as a basis for straightforward and accurate design of devices and applications for efficient electronic signal processing in graphene at ultrahigh frequencies.

scholarly journals Broadband Plasmonic Nanopolarizer Based on Different Surface Plasmon Resonance Modes in a Silver Nanorod

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 447
Author(s):  
Junxi Zhang ◽  
Lei Hu ◽  
Zhijia Hu ◽  
Yongqing Wei ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Electric Fields ◽  
Near Infrared ◽  
Near Field ◽  
Resonant Cavity ◽  
Transverse Magnetic ◽  
Wave Mode ◽  
Fdtd Simulation ◽  
Nanophotonic Devices ◽  
Resonance Modes ◽  
Polarization Characteristics

Conventional polarizers including sheet, wire-grid, prism, and Brewster-angle type polarizers are not easily integrated with photonic circuits. Polarizing elements on the nanoscale are indispensable for integrated all-optical nanophotonic devices. Here, we propose a plasmonic nanopolarizer based on a silver nanorod. The polarization characteristics result from the excitation of different resonance modes of localized surface plasmons (LSPs) at different wavelengths. Furthermore, the polarization characteristics in near field regions have been demonstrated by the electric field distribution of the nanorod based on finite-difference time-domain (FDTD) simulation, indicating a strong local resonant cavity with a standing wave mode for transverse electric (TE) polarization and weak electric fields distributed for transverse magnetic (TM) polarization. The nanopolarizer can efficiently work in the near field region, exhibiting a nanopolarization effect. In addition, very high extinction ratios and extremely low insertion losses can be achieved. Particularly, the nanopolarizer can work in a broadband from visible to near-infrared wavelengths, which can be tuned by changing the aspect ratio of the nanorod. The plasmonic nanopolarizer is a promising candidate for potential applications in the integration of nanophotonic devices and circuits.

HIGH FREQUENCY GAS DISCHARGE BREAKDOWN IN NEON

1952 ◽  
Vol 30 (5) ◽  
pp. 565-576 ◽  
Author(s):  
A. D. MacDonald ◽  
D. D. Betts
Keyword(s):  
Kinetic Theory ◽  
Electric Fields ◽  
Cross Sections ◽  
Electrical Breakdown ◽  
Ionization Rate ◽  
Gas Discharge ◽  
Distribution Functions ◽  
Boltzmann Transport ◽  
Discharge Data ◽  
Confluent Hypergeometric Functions

Electrical breakdown of neon at high frequencies has been treated theoretically on the basis of the Boltzmann transport equation. Exciting and ionizing collisions are accounted for as energy loss terms in the Boltzmann equation and measured values of the ionization efficiency are used in the integral determining the ionization rate. Electrons are lost to the discharge by diffusion. The equations are treated separately for the cases in which the collision frequency is much less than or much greater than the radian frequency of the applied field. The electron energy distribution functions are expressed in terms of Bessel functions, confluent hypergeometric functions, and simple exponentials. The ionization rate and the diffusion coefficient are calculated using these distribution functions in kinetic theory formulas, and combined with the diffusion equation to predict breakdown fields. The theoretically predicted fields are compared with experiment at 3000 Mc. per sec. The breakdown equations, calculated from kinetic theory and using no gas discharge data other than collision cross sections, predict breakdown electric fields within the limits of accuracy determined by these cross sections over a large range of experimental variables.

scholarly journals Reduction of Electric Breakdown Voltage in LC Switching Shutters / Elektriskās Caursites Sprieguma Samazināšana Šķidro Kristālu Šūnās

2015 ◽  
Vol 52 (5) ◽  
pp. 47-57 ◽  
Author(s):  
G. Mozolevskis ◽  
A. Ozols ◽  
E. Nitiss ◽  
E. Linina ◽  
A. Tokmakov ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Electric Fields ◽  
Electrical Breakdown ◽  
Liquid Crystal Display ◽  
Threshold Value ◽  
Buffer Layers ◽  
Limiting Factors ◽  
Dust Particles ◽  
Crystal Layer ◽  
Liquid Crystal Layer

Abstract Liquid crystal display (LCD) industry is among the most rapidly growing and innovating industries in the world. Here continuously much effort is devoted towards developing and implementing new types of LCDs for various applications. Some types of LCDs require relatively high voltages for their operation. For example, bistable displays, in which an altering field at different frequencies is used for switching from clear to scattering states and vice versa, require electric fields at around 10 V/μm for operation. When operated at such high voltages an electrical breakdown is very likely to occur in the liquid crystal (LC) cell. This has been one of the limiting factors for such displays to reach market. In the present paper, we will report on the results of electrical breakdown investigations in high-voltage LC cells. An electrical breakdown in the cell is observed when current in the liquid crystal layer is above a specific threshold value. The threshold current is determined by conductivity of the liquid crystal as well as point defects, such as dust particles in LC layer, pinholes in coatings and electrode hillocks. In order to reduce the currents flowing through the liquid crystal layer several approaches, such as electrode patterning and adding of various buffer layers in the series with LC layer, have been tested. We demonstrate that the breakdown voltages can be significantly improved by means of adding insulating thin films.

scholarly journals Theoretical–Computational Study of Atmospheric DBD Plasma and Its Utility for Nanoscale Biocompatible Plasmonic Coating

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 5106
Author(s):  
Taj Muhammad Khan ◽  
Shahab Ud-Din Khan ◽  
Muhammad Raffi ◽  
Riaz Khan
Keyword(s):  
Electric Fields ◽  
Electrical Breakdown ◽  
Computational Study ◽  
Plasma Jet ◽  
Visible Spectral Region ◽  
Time Dependent ◽  
Half Cycle ◽  
Dbd Plasma ◽  
One Dimensional ◽  
Plasma Device

In this study, time-dependent, one-dimensional modeling of a surface dielectric barrier discharge (SDBD) device, driven by a sinusoidal voltage of amplitude 1–3 kV at 20 kHz, in argon is described. An SDBD device with two Cu-stripe electrodes, covered by the quartz dielectric and with the discharge gap of 20 × 10−3 m, was assumed, and the time-dependent, one-dimensional discharge parameters were simulated versus time across the plasma gap. The plasma device simulated in the given arrangement was constructed and used for biocompatible antibacterial/antimicrobial coating of plasmonic particle aerosol and compared with the coating strategy of the DBD plasma jet. Simulation results showed discharge consists of an electrical breakdown, occurring in each half-cycle of the AC voltage with an electron density of 1.4 × 1010 cm−3 and electric field strength of 4.5 × 105 Vm−1. With SDBD, the surface coating comprises spatially distributed particles of mean size 29 (11) nm, while with argon plasma jet, the nanoparticles are aggregated in clusters that are three times larger in size. Both coatings are crystalline and exhibit plasmonic features in the visible spectral region. It is expected that the particle aerosols are collected under the ionic wind, induced by the plasma electric fields, and it is assumed that this follows the dominant charging mechanisms of ions diffusion. The cold plasma strategy is appealing in a sense; it opens new venues at the nanoscale to deal with biomedical and surgical devices in a flexible processing environment.

Membrane Fusion and Deformation of Red Blood Cells by Electric Fields

1980 ◽  
Vol 35 (11-12) ◽  
pp. 1081-1085 ◽  
Author(s):  
Peter Scheurich ◽  
Ulrich Zimmermann ◽  
Maja Mischel ◽  
Ingolf Lamprecht
Keyword(s):  
Electric Field ◽  
Red Blood Cells ◽  
Membrane Fusion ◽  
Electric Fields ◽  
Blood Cells ◽  
Electrical Breakdown ◽  
Osmotic Shock ◽  
Sine Wave ◽  
Hypotonic Solution ◽  
Alternating Electric Field

Abstract Human red blood cells suspended in a slightly hypotonic solution of low electric conductivity were exposed to an inhomogeneous and alternating electric field (sine wave, 30 V peak-to-peak value, electrode distance 120 μm, 0.5 to 2 MHz). Due to the dielectrophoretic effect the cells align parallel to the field lines under the formation of pearl chains. At high voltages (10 V amplitude) membrane fusion is observed between the adhered red blood cells in the pearl chains, whereby the chains become attached to the electrodes. In contrast to the pearl chains observed at voltages of up to 5 V amplitude the resulting fused and uniform aggregates which exhibit no recognisable individual cells under the light microscope, remain stable, even after the alternating electric field has been switched off or after haemolysis in response to osmotic shock. The fused aggregates are highly elastic. If the field strength of the applied alternating electric field is further increased they are stretched in the direction of the opposite electrode. Frequently, bridges are formed between the two electrodes. The uniform bridges remain stable for some time even in the absence of an electric field. The possibility of cell fusion and its initiation by electrical breakdown of the cell membranes are discussed.

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