• Analytical Science and Technology
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• v.6 no.4
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• pp.369-374
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• 1993

Plasma oscillation has been observed during the development of the glow discharge as detector for gas chromatography. The variation of oscillation frequency shows the better stability and detection limits than the changes in the dischange curent. To investigate the range of useful operating conditions and to gain insight into the mechanism, the effect of experimental parameters on plasma oscillation have been studied. This study includes the variation of discharge current, pressure and discharge gap. Frequency ranges of 10KHz to 10MHz have been observed with the various shapes of oscillation. Two kinds of mode for oscillation are observed with the variation of electrode gap at low pressure and low voltage.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.480-480
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• 2007

A large diameter plasma filled backward wave oscillator is investigated experimentally. The parameters of slow wave structure are chosen so that the oscillation frequency is high beam energy. Plasma is produced by the beam and it has favorable effects on beam propagation and Cerenkov oscillation.

• Current Optics and Photonics
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• v.1 no.5
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• pp.544-550
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• 2017

This simulation based study reports a novel tunable, compact, room temperature terahertz (THz) transistor source, operated on the concept of charge plasma oscillation with the capability of radiating within a terahertz gap. A vertical cavity with a quasi-periodic distributed-Bragg-reflector has been attached to a THz plasma wave transistor to achieve a monochromatic coherent surface emission for single as well as multi-color operation. The resonance frequency has been tuned from 0.5 to 1.5 THz with the variable quality factor of the optical cavity from 5 to 290 and slope efficiency maximized to 11. The proposed surface emitting terahertz transistor is able to satisfy the demand for compact solid state terahertz sources in the field of teratronics. The proposed device can be integrated with Si CMOS technology and has opened the way towards the development of silicon photonics.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.12
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• pp.1880-1885
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• 2012

Nonlinear dynamical behaviors in thermionic low pressure discharge are investigated using a particle-in-cell(PIC) simulation. An electrostatic PIC code is developed to model the plasma discharge system including the kinetic effects. The elastic collision, excitation collision, ionization collision, and electron-ion recombination collision are considered in this code. The generated electrons and ions are traced to analyze physical characteristics of the plasma. The simulation results show that the nonlinear oscillation structures are observed for cold plasma in the system and the similar structures are observed for warm plasma with a shift in values of the bifurcation parameter. The detailed oscillation process can be subdivided into three distinct mode; anode-glow, temperature-limited, and double-layer modes.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.53.2-53.2
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• 2019

$H{\alpha}$ surges (i.e. cool/dense collimated plasma ejections) may act as a guide for a propagation of magnetohydrodynamic waves. We report a high-resolution observation of a surge observed with 1.6m Goody Solar Telescope (GST) on 2009 August 26, from 18:20~UT to 18:45UT. Characteristics of plasma motions in the surge are determined with the normalizing radial gradient filter and the Fourier motion filter. The shape of the surge is found to change from a 'C' shape to an inverse 'C' shape after a formation of a cusp, a signature of reconnection. There are apparent upflows seen above the cusp top and downflows below it. The upflows show rising and rotational motions in the right-hand direction, with the rotational speed decreasing with height. Near the cusp top, we find a transverse oscillation of the surge, with the period of ~2 min. There is no change of the oscillation phase below the cusp top, but above the top a phase change is identified, giving a vertical phase speed about 86kms-1. As the height increases, the initial amplitude of the oscillation increases, and the oscillation damping time decreases from 5.13 to 1.18min. We conclude that the oscillation is a propagating kink wave that is possibly excited by an x-point oscillation.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.10
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• pp.517-521
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• 2001

The voltage controlled ramp(VCR) waveform has recently been introduced in the reset period prior to addressing for plasma display. However, this method shows the oscillation of gap voltage when the ramp rate is increased in order to reduce reset period. In this paper a current controlled ramp(CCR) waveform method is suggested. This method can suppress the oscillation of gap voltge under the condition of shorter ramp time. Moreover, the reset time can be reduced about 30% compared with VCR method under the same background luminance.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.585-587
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• 2009

A large diameter slot waveguide made backward wave oscillator is investigated experimentally. The parameters of slow wave structure are chosen so that the oscillation frequency is about 20 GHz. Plasma is produced by the beam and it has favorable effects on beam propagation and Cherncov oscillation. The output power strongly enhanced when the guiding magnetic field approaches to the fundamental electron cyclotron resonance.

• YAKHAK HOEJI
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• v.37 no.1
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• pp.76-83
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• 1993

The changes in discharge current, emission and/or oscillation frequency of the electric oscillation of a glow discharge are the potential sensitive measure of the concentration of an impurity in the argon plasma supporting gas. A single jet enhanced glow discharge has been interfaced with the gas chromatograph via 1/8" O.D. tube with a heating pad to study the changes in discharge current. To investigate the optimum operating conditions of the glow discharge system as detector for gas chromatography, pressure, gas flow rate, discharge current, distance between the anode and the cathode have been studied.

• Development and Reproduction
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• v.24 no.4
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• pp.297-306
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• 2020

Repetitive changes in the intracellular calcium concentration ([Ca²⁺]i) triggers egg activation, including cortical granule exocytosis, resumption of second meiosis, block to polyspermy, and initiating embryonic development. [Ca²⁺]i oscillations that continue for several hours, are required for the early events of egg activation and possibly connected to further development to the blastocyst stage. The sources of Ca²⁺ ion elevation during [Ca²⁺]i oscillations are Ca²⁺ release from endoplasmic reticulum through inositol 1,4,5 tri-phosphate receptor and Ca²⁺ ion influx through Ca²⁺ channel on the plasma membrane. Ca²⁺ channels have been characterized into voltage-dependent Ca²⁺ channels (VDCCs), ligand-gated Ca²⁺ channel, and leak-channel. VDCCs expressed on muscle cell or neuron is specified into L, T, N, P, Q, and R type VDCs by their activation threshold or their sensitivity to peptide toxins isolated from cone snails and spiders. The present study was aimed to investigate the localization pattern of N and P/Q type voltage-dependent calcium channels in mouse eggs and the role in fertilization. [Ca²⁺]i oscillation was observed in a Ca²⁺ contained medium with sperm factor or adenophostin A injection but disappeared in Ca²⁺ free medium. Ca²⁺ influx was decreased by Lat A. N-VDCC specific inhibitor, ω-Conotoxin CVIIA induced abnormal [Ca²⁺]i oscillation profiles in SrCl₂ treatment. N or P/Q type VDC were distributed on the plasma membrane in cortical cluster form, not in the cytoplasm. Ca²⁺ influx is essential for [Ca²⁺]i oscillation during mammalian fertilization. This Ca²⁺ influx might be controlled through the N or P/Q type VDCCs. Abnormal VDCCs expression of eggs could be tested in fertilization failure or low fertilization eggs in subfertility women.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2008.05a
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• pp.43-45
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• 2008