• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권5호
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• pp.203-210
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• 2003

This paper describes high voltage and high energy density capacitor developed for pulsed power applications. The rated voltage of the developed capacitor is DC 22 [kV], the capacitance is 206 [$\mu$F] and the energy density is about 0.7 [kJ/kg]. Polypropylene film and kraft paper were used as the dielectrics. The ratio of the thickness of each dielectric material which consists of the composite dielectric structure, stacking factor and the termination method were determined by the charging and discharging tests on model capacitors. In terms of energy density, the developed capacitor has higher energy density compared with the products of foreign leading companies. In addition, it has been proved that the life expectancy can be more over 2000 shots through the charging and discharging test. The voltage reversal factor was 20%. This capacitor can be used as numerous discharge applications such as military, medical, industrial fields.

• 화약ㆍ발파
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• 제24권2호
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• pp.1-8
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• 2006

본 연구는 규석광의 터널 굴착시 굴진장 향상과 사압현상 및 소결현상을 예방하기 위해 모든 장약공의 장약밀도를 다르게 적용하였다. 이 때 심발공은 동일 장약공내에 2개의 뇌관을 이용한 정기폭과 역기폭의 복합기폭방식을 도입하였다. 자유면 형성이 어려운 공저부분은 높은 장약밀도로 장전하고, 주상부분은 공저보다 낮은 장약밀도로 장전함으로써 폭약의 위력이 효과적으로 암반에 대응할 수 있는 공법인 복합장약기폭시스템을 개발하였다. 그 결과 경암이나 장공발파에서 흔히 발생되는 사압현상 및 소결현상 등을 방지할 수 있었다. 또한 1회 천공장 대비 굴진장을 95% 이상 증대시킴으로써 약 15% 정도의 시공능율이 향상되고 비장약량이 20% 정도 감소되었다.

• 한국표면공학회지
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• 제46권3호
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• pp.126-132
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• 2013

It was investigated that the effects of hydrogen charging on the properties of 590 MPa Dual Phase(DP) steels at the surface layers. The hydrogen-charging time was changed from 5 to 50 hours and current densities from 100, 150, and 200 $mA/cm^2$, respectively. It was found that the hydrogen content in the specimen was increased with as the charging time and the current density. The microvickers hardness of the subsurface zone was increased from 215.3 HV to 239.5 HV due to the increase in current density and charging time. The comparison of the absorbed energies tested by a small-punch (SP) test showed that the absorbed energy of the specimen was greatly reduced from 436 to 283 $kgf-mm^2$ because of hydrogen embrittlement. It was confirmed that bulb aspects of fracture surface became more brittle with increasing hydrogen content.

• 한국전기전자재료학회논문지
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• 제35권4호
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• pp.322-332
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• 2022

Energy storage capacitors based on dielectric ceramics with superior polarization properties and dielectric constant can provide much higher output power density due to their very fast energy charging/discharging rates, which are particularly suitable for operating pulsed-power devices. For an outstanding energy storage performance of dielectric capacitor, a large recoverable energy density could be derived by introducing a slim polarization-electric field hysteresis loop into dielectric materials by various technical approaches. Many research teams have explored various dielectric capacitor technologies to demonstrate high output power density and ultrafast charging/discharging behavior. This article reviews the recent research progress in high-performance dielectric capacitors for pulsed-power electronic applications.

• 한국재료학회지
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• 제31권2호
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• pp.84-91
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• 2021

To cope with automobile exhaust gas regulations, ISG and charging control systems are applied to HEV vehicles for the purpose of improving fuel economy. These systems require quick charge-discharge performance of high current. Therefore, a Module of the AGM battery with high energy density and EDLC(Electric Double Layer Capacitor) with high power density are constructed to study the charging and discharging behavior. In CCA, which evaluates the starting performance at -18 ℃ & 30 ℃ with high current, EDLC contributed for about 8 sec at the beginning. At 0 ℃ CA (Charge Acceptance), the initial Charging current of the AGM/EDLC Module, is twice that of the AGM lead acid battery. To play the role of EDLC during high-current rapid charging and discharging, the condition of the AGM lead-acid battery is optimally maintained. As a result of a Standard of Battery Association of Japan (SBA) S0101 test, the service life of the Module of the AGM Lead Acid Battery/EDLC is found to improve by 2 times compared to that of the AGM Lead Acid Battery.

• 한국가스학회지
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• 제19권1호
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• pp.64-70
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• 2015

TRIP강의 수소에 의한 취성화정도를 확인하기 위하여 산성과 알칼리성 전해질 분위기 하에서 전류밀도와 주입시간을 달리하여 수소를 강제주입시킨 후 sp시험으로 평가하고자 하였다. SP시험결과 산성 전해질 분위기가 알칼리성 전해질 분위기에 비해 수소 취성화가 더욱 민감하게 반응하는 것으로 조사되었다. 또한 산성 전해질은 주입시간과 전류밀도가 수소취성화에 영향을 미치는 인자로 확인되었으며, 알칼리성 전해질은 주입시간이 전류 밀도보다 수소 취성화를 촉진하는 요소로 조사되었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.582-585
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• 2012

The aluminum extruded panel used for a high speed train shows the largest contribution to sound insulation performance of the train body. However, comparing with the flat panel having the same weight, the transmission loss falls sharply in the local resonance frequency band. Such fall of transmission loss can be improved by increasing the damping of local resonance. This study examines the charging effect of an urethane foam on the aluminum extruded panel of a high speed train. We charged the urethane foam with different mass density and in different way in the core part of the extruded panel. We measure the transmission loss and compare the sound insulation performance according to the density and charging method. Finally, Improvement effect of the transmission loss is compared and analysed in aspect of weight increment.

• 한국전기전자재료학회논문지
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• 제14권5호
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• pp.417-422
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• 2001

The needs of new materials that substitute Si Oxide capacitor layer in high density DRAM increase. So in this paper, we choose the slim region 14/50/50 PLZT composition and fabricated thin films by PLD and estimated the characteristics for DRAM application. 14/50/50 PLZT thin films have crystallized into perovskite structure in the $600^{\circ}C$ deposition temperature and 200 mTorr Oxygen pressure. In this condition, PLZT thin films had 985 dielectric constant, storage charge density 8.17 $\mu$C/$\textrm{cm}^2$ and charging time 0.20ns. Leakage Current density was less than 10$^{-10}$ A/$\textrm{cm}^2$ until 5V bias voltage.

• 한국표면공학회지
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• 제47권5호
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• pp.257-262
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• 2014

In this paper, the behavior of hydrogen embrittlement of 680MPa DP sheet steel according to hydrogen charging conditions in acid and alkali electrolytes atmosphere was investigated. At this time, 0.5 M $H_2SO_4$ and 0.5M NaOH was used for electrolytes atmosphere and the effect on embrittlemnet of 680MPa DP sheet steel according to current density and charging time was evaluated by the change of subsurface microhardness in DP specimens chared hydrogen. As a result of this experiment, the microhardness of the layer directly below the surface was increased more than the microhardness of the subsurface zone in both electrolytes cases, but the change of the subsurface microhardness in both electrolytes was more affected by the increase of charging time than the increase of current density. The microhardness of subsurface zone in 0.5 M $H_2SO_4$ acid electrolyte was increased more than the microhardness in 0.5M NaOH alkali electrolyte. It was supposed that acid atmosphere was more sensitive to hydrogen embrittlement than alkali atmosphere on electrolyte atmosphere of hydrogen charge.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1984년도 하계학술회의논문집
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• pp.226-229
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• 1984

A novel high intensity charging device has been developed for the control of the submicron particles, such as the diesel soot particulates, which are very hard to charge highly by any means of the conventional charging device. Having new corona electrodes of a multineedle disk with the corona field-control electrodes in the outer-cylinder electrode, extremely intense and stable coronas on there sharp points expanding both radially and axially are established in the corona charging region between the multi-corona -needles and an outer-cylinder electrode. As a result, the maximum corona field intensity and current density of the charging device of the standard one on soot load in laboratory tests have been 8.5KV/cm(E=$2V_m$/D(1nD/d)) and $6.5{\mu}A/cm^2$ which enhance greatly the charging of soot particles about several 100 times higher than those obtained in conventional cylinder precipitators.