• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2005년도 추계종합학술대회
• /
• pp.833-836
• /
• 2005

Nano-gap trench is fabricated by the novel electrochemical etching technique using forward biased PN junction formed at the backside of the wafer. PN junction is formed using boron nitride wafer and the concentration of the boron doping is the high value of $1{\times}10^{19}$ $cm^{-3}$. The electro-chemical etching is performed in the 5% HF solution under the forward bias voltage of $1{\sim}2V$. The relationship between the etch rate of the trench and the voltage of the forward bias is investigated and the dependence of the gap for the voltage also examined. The etch rate increase from 0.027 ${\mu}m/min$ to 0.031 ${\mu}m/min$ as the value of the applied voltage increase from 1V to 2V, but the the gap is kept constant value of 40 nm.

• 전기의세계
• /
• 제22권2호
• /
• pp.57-69
• /
• 1973

The aim of this study was to investigate the behaviors of plasma jet under coaxial magnetic field in paralled with it for controlling optical characteristics and input power of plasma jet without impurity and instability of arc plasma column. Because the discharge characteristics of plasma jet were so distinctively different according to the existence or non-existence of magnetic field, the input power, luminous intensity of plasma jet and thermal efficiency were comparatively studied in respect of such variables as arc current, gap of electrode, quantity of argon flow, magnetic flux density, diameter and length of nozzle, with the use of several materials which were different in diameter and length of nozzel. The results were as follows; 1) The voltage tends to show a drooping characteristic at law current and then rises gradually. The luminous intensity of plasma jet increases exponentially with arc current. 2) Arc voltage increases and luminous intensity tends to decrease gradually as gap of electrode increases. 3) Arc voltage and luminous intensity tends to decrease gradually as gap of electrode increases. 3) Arc voltage and luminous intensity increase in accordance with the quantity of argon flow. 4) At first step, arc voltage increases to maximum value with the growth of flux density and then tends to show a gradual decrease. Luminous intensity decreases with the growth flux density. 5) Arc voltage decreases as the constriction length of nozzle increases, maximum decrease is shown at the constriction length of 20(mm) and it increases beyond that value. The luminous intensity decreases as the constriction length grows. 6) Arc voltage and luminous in tensity increase with the growth of diameters of nozzle. 7) Thermal efficiency has values between 50% and 75%, being influenced by arc current, the quantity of argon flow, flux density, the length of electrode gap and the constriction length of nozzle.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1997년도 하계학술대회 논문집 E
• /
• pp.1770-1772
• /
• 1997

In this paper, Voltage-time characteristics of lightning impulse and switching surge breakdown in SF6 is studied on the gap and various pressure. The characteristics is categorized into three pattern depending on the configuration of the gap and gas pressure. The properties of the voltage-time characteristics in these patterns are generalized as semi-empirical formula which will be useful in the quantitation voltage evaluation of insulation coordination and the abnormal voltage protection of SF6 insulated power equipment.

• 한국안전학회지
• /
• 제19권1호
• /
• pp.56-59
• /
• 2004

In this paper, we investigated the influence of gap length and tip radius on breakdown of mineral based insulation oil. Applied voltages were DC and AC voltage. Electrode system was needle-plane structure. The tip radius of needle electrode was 5, 10, 20 and 25${\mu}m$, respectively. We measured breakdown voltage for each of tip radius with increasing electrode gap, 2mm to 12mm. Electric breakdown strength at tip was calculated using Mason's equation contained geometric figure. As gap length increased, breakdown strength increased linearly. But, as tip radius of needle increased, breakdown strength decreased exponentially. It can be explained by the phenomenon that electron is easily injected, as tip radius increases, and effective work function decreases. When appling DC voltage, breakdown strength was higher when polarity of needle was negative than positive. It is because of the space charge effect in accordance with the influence of liquid motion.

• 한국생산제조학회지
• /
• 제5권1호
• /
• pp.17-26
• /
• 1996

In this paper, we have studied about the relationships between a core gap and a feeding velocity, an amplitude and the core gap by the exciting force, the parts movement and a bowl materials, and the feeding velocity and the weight of the parts in the parts feeder. The obtained are as follow : 1) Optimal condition of mean feeding velocity is speeded up largely when the core gap is in 0.6mm. 2) It can be safe to say that the relation between the feeding velocity and the exciting voltage relay on the core gap. 3) An exciting voltage is rised by an increase of the weight, but an amplitude has been in the range between 23$mu extrm{m}$ through 40${\mu}{\textrm}{m}$.

• Progress in Superconductivity
• /
• 제3권2호
• /
• pp.146-150
• /
• 2002

We performed the point contact spectroscopy on newly discovered superconductor $MgB_2$ thin films with Au tip. In the point contact spectroscopy of the metallic Sharvin limit, the differential conductance below the gap is twice as that above the gap by virtue of Andreev Reflection. After some surface cleaning processes of sample preparation such as ion-milling and wet etching, the obtained dI/dV versus voltage curves are relatively well fitted to the Blonder-Tinkham-Klapwijk (BTK) formalism. Gaps determined by this technique were distributed in the range of 3meV~ 8meV with the BCS value of 5.9meV in the weak coupling limit. We attribute these discrepancies to the symmetry of the gap parameter and the degradation of the surface of the sample. We also present the temperature dependence of the conductance vs voltage curve and thereby the temperature dependence of the gap.

• 한국정밀공학회지
• /
• 제13권1호
• /
• pp.22-28
• /
• 1996

From the experimental study of Wire-Cut Electric Discharge Machining of STD-11 alloy steel and P-20 tungsten carbide, the characteristics such as hand drum form and discharge gap have been observed and evaluated for various conditions. Hand drum form can be improved when gap have been observed and evaluated for various conditions. Hand drum form can be improved when gap voltage and spark cycle become smaller, thickness become thinner, wire tension become larger and the no of cutting increases. When 60mm thickness tungsten carbide is cut in normal condition, hand drum form becomes larger due to the low conductivity machining allowance become slightly larger when peak discharge current and gap voltage become larger, or wire tension becomes smaller. Under the same condition, machining allowance of tungsten carbide is larger than alloyed steel by 1/100mm.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 하계학술대회 논문집 C
• /
• pp.1145-1148
• /
• 1999

This paper is introducing a newly developed spark gap switch with dual trigger system, into which the current from the voltage source is injected along wi th the test sequence during the synthetic testing of high voltage circuit-breaker.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
• /
• pp.89-90
• /
• 2008

본 논문에서는 전압과 마찰전기에 의하여 전하를 가진 대전입자가 운동을 기반으로 이미지를 구현하는 대전입자형 디스플레이의 패널을 셀과 전극이 형성된 상판과 하판으로 제작하였으며, 각 패널은 격벽높이를 다르게 하여 대전입자층을 여러 층으로 addressing하여 spacer로 cell gap에 변화를 두어 합착하였다. 합착한 패널에 낮은 전압부터 인가하여 threshold voltage와 driving voltage, breakdown voltage를 확인하여 선명한 이미지 구현을 할 수 있었다.

• 전기학회논문지
• /
• 제65권9호
• /
• pp.1571-1576
• /
• 2016

A Tesla coil is an electrical resonant transformer circuit invented by Nikola Tesla in 1891. It is used to produce high-voltage, low-current, high frequency alternating-current electricity. Tesla coil can generate a long streamer with several million volts of electricity as a high voltage device. It is basically consists of a voltage transformer, high voltage capacitor, spark gap, primary coil, secondary coil and toroid. It is difficult to appear in the output size of the streamer is controlled by the spark gap. The general decision method of the length of streamer is to display the electric output in accordance with the design specifications in initial development plan. Design specifications and the electric output is determined by the application of facilities. In this paper the spark gap is replaced with periodic switching semiconductor device to control output voltage easily in order to apply overvoltage protective circuit due to a secondary coil and a performance test. In these days, their main use is for entertainment and educational displays of the museum, although small coils are still used as leak detectors for high vacuum systems.