• 자원환경지질
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• 제30권6호
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• pp.637-644
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• 1997

Active young back-arc basin such as Mariana, Havre, Lau, Manus, East Scotia basins have asymmetric topography of two types in respect to the spreading axis. The arc-trench wing of Mariana Trough, Lau basin and Havre Trough are shallower toward the active arc, whereas those Manus and East Scotia basins are nearly symmetric to the opposite wings. The other asymmetry which shows the spreading axis deviated from the geographic axis toward the active arc is observed in each basin. Active young back-arc basins show a large variety of asymmetry rates ranging from the lowest East Scotia Basin to the highest Mariana Trough. The asymmetric topography of these young back-arc basins seems to be caused by the rollback rate of downgoing slab under the basin. As the rollback rate increases, the asymmetry rate systematically decreases.

• 한국전자파학회논문지
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• 제23권1호
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• pp.29-37
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• 2012

본 논문에서는 능동 위상 배열 안테나(APAA: Active-Phased Array Antenna)의 능동 반사 계수(ARC: Active Reflection Coefficient) 개선 및 보호 회로 구성을 통한 안정적인 시스템 운용에 관하여 연구하였다. 수동 위상배열 안테나에서와 달리 APAA는 복사 소자와 송수신 모듈이 결합된 형태로 일반적인 수동 위상 배열 안테나의 반사 계수 특성과 차별된 새로운 ARC의 정의가 적용되어야 한다. ARC는 방사하는 소자로부터의 자기 반사계수 외에 인접한 방사 소자로부터 유기되는 결합량의 중첩을 고려한 반사 계수이다. 이는 능동 위상 배열 레이더(APAR: Active-Phased Array Radar) 시스템의 특성을 예측하고 분석하는데 중요한 파라미터가 된다. 운용 중 발생하는 높은 ARC는 시스템 성능 열화에 직접적인 원인이 된다. 본 논문에서는 APAR의 안정적인 운용을 위한 방안으로 ARC의 성능을 개선시키는 방안과 보호 회로를 통한 열화 방지 방안에 관하여 분석하였다. 실제 제작한 능동 위상 배열 안테나의 실험 결과를 통해 두 방안의 유효성을 검증하였다.

• 핵의학기술
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• 제22권1호
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• pp.84-89
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• 2018

Purpose Renin is a proteolytic enzyme synthesized and secreted from epidermal(juxtaglomerular) cells in kidney. Renin acts on the renin substrate angiotensinogen to produce angiotensin I, and then angiotensin II is produced by the action of angiotensin converting enzyme. This causes the adrenal glands to boost blood pressure (vasoconstriction) and promote aldosterone secretion. While Plasma renin activity (PRA) is to test angiotensin I, the active renin concentration (ARC) is a renin test directly. They have different test methods and their own substrates. However, these two methods are sometimes interpreted as the same as a result. The purpose of this study was to evaluate the usefulness of the ARC test by comparing the results between PRA and ARC. Materials and Methods For the diversity of the experiment, 26 samples were requested to test with PRA(TFB company) and ARC(Cisbio company) to other institution. We compared and analyzed PRA(Immunotech company) and ARC(Cisbio company) tests using 28 samples from September $15^{th}$ to October $13^{th}$ in 2017. The statistical analysis method for PRA/ARC evaluated the usefulness using Microsoft Excel program by verifying a correlation analysis of Aldosterone/PRA ratio and a correlation analysis of Aldosterone/ARC ratio and conducting T-test. Results The regression equation of the PRA(Immunotech company)/ARC(Cisbio company), which was tested in the department, was y = 0.0619x + 0.4615 and the correlation coefficient was 0.73. The regression equation of the PRA(TFB company)/ARC(Cisbio company), which was tested in the other institution, was y = 0.0888x + 0.3316 and the correlation coefficient was 0.91. In addition, The regression equation of Aldosterone / PRA ratio and Aldosterone / ARC ratio was y = 0.875x - 11.688 and the correlation coefficient was 0.87. Plus T - test showed no significant difference (P>0.05). Conclusion Both tests showed a strong positive correlation, but this only represents the strength and direction of the relationship between the two tests. Furthermore, the actual results showed somewhat differences. It is presumed that the measured value was influenced by the endogenous renin group mass in the plasma, the condition of the enzyme reaction and the kind of the inhibitor. When the active renin concentration (ARC) test is performed, it is useful to distinguish between the two tests as they are complementary.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.581-586
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• 2000

Gas metal arc welding(GMAW) uses a continuously fed electrode as a filler metal. The arc is shielded from atmospheric contamination by an inert gas active or inert/active gas mixture delivered through the welding gun and cable assembly. The recent research topics on $CO_2$ are welding machines are focused mainly on the reduction method of generated spatter by using new type consumable electrode metal or inverter control method. The various current waveform control methods have been researched for welding performance improvement. Until now current waveform control methods reduce to spatter occurred by instantaneous short circuiting,. but these methods is drawback that no reduce spatter occurred by arc reignition. In this paper the previous arc reignition current control method for welding performance improvement of inverter arc welding machine is studied and compared the various current control methods with the previous arc reignition current control method.

• 전기학회논문지
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• 제57권8호
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• pp.1470-1477
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• 2008

In this paper, a new detection method of series arc-fault signals occurring at the wiring of home appliances is proposed. The discrete wavelet transform was used for the numerical analysis of the variation rate in peak, RMS, noise energy, shoulder of the arc-fault current wave. As a results, the arc distinction threshold value of these variation rates was about 0.1 in most cases. The arc-fault current of the loads with the active PFC circuit showed a high rate of variation in noise energy and shoulder, but arc-fault current of the loads without the active PFC circuit showed a high rate of variation in peak and RMS. The arc fault current in resistive loads showed a high rate of variation in shoulder.

• Journal of Welding and Joining
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• 제32권5호
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• pp.26-31
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• 2014

Conventional TIG(C-TIG) welding process guarantees higher quality weldment when compared with other processes. However, C-TIG with inherent low penetration shows disadvantages in productivity, especially for thick-walled structure. To overcome these handicaps, active-flux TIG(A-TIG) welding has been introduced and studied widely in a motivation to improve both quality and productivity. Present study made a focus on optimum combination of oxide components to enhance arc contraction and penetration. Results indicated that arc contraction inducing enhancement of penetration could be possible when composition of active fluxes was well matched with base metal.

• Journal of Welding and Joining
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• 제26권6호
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• pp.42-47
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• 2008

TIG welding enables to produce high quality weldment. However it has some problems such as shallow penetration and large distortion due to low penetration aspect ratio after welding. In order to overcome those problems, there are many ongoing studies on A-TIG welding, which use active flux. In this study, the effect of arc length and shield gas on penetration aspect ratio with melt-run welding on STS 304 6t, on which active flux was spreaded, was investigated. Arc length was changed from 1mm to 3mm, and aspect ratio became higher as arc length was decreased in this range. 100% Ar gas, Ar-$H_2$ mixed gas, Ar-He mixed gas, and 100% He gas were used as shield gas in this study. When Ar-$H_2$ mixed gas, Ar-He mixed gas, and 100% He gas were applied, penetration and melting efficiency were both increased as compared with 100% Ar gas. Aspect ratio was the highest with Ar-2.5% $H_2$ mixed gas.

• 한국산학기술학회논문지
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• 제8권3호
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• pp.444-453
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• 2007

최근에 전기 아-크로의 보급과 그 운전으로 전력계통에 전압플리커 및 유효전력변동과 같은 전력품질상의 문제가 발생될 가능성이 높은 것으로 보고되고 있다. 이 문제를 해결할 수 있는 방법에는 대표적으로 무효전력보상방법이 있는데, 이것은 유효전력변동의 전력품질문제해결에는 한계가 있다. 따라서, 본 논문에서는 이의 해결책으로서 X/R 비율에 근거한 유효전력보상 개념과 그 최적앨고리즘을 제안하여 이의 타당성을 모델링과 시뮬레이션을 통하여 검증하였다.

• Journal of Electrical Engineering and Technology
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• 제1권2호
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• pp.153-160
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• 2006

This paper presents a new compensating system, which consists of a shunt active filter and passive components for mitigating voltage and current disturbances arising from an Electric Arc Furnace (EAF). A novel control strategy is presented for the shunt active filter. An extended method based on instantaneous power theory in a rotating reference frame is developed for extraction of compensating signals. Since voltages at the point of common coupling contain low frequency interharmonics, conventional methods cannot be used for dc voltage regulation. Therefore, a new method is introduced for this purpose. The passive components limit the fast variations of load currents and mitigate voltage notching at the Point of Common Coupling (PCC). A three-phase electric arc furnace model is used to show power quality improvement through reactive power and harmonic compensation by a shunt active filter using the proposed control method. The system performance is investigated by simulation, which shows improvement in power quality indices such as flicker severity index.

• 천문학회보
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• 제44권1호
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• pp.83.2-83.2
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• 2019

We study the stability of the magnetic structure in active region (AR) 12371 producing an M6.5 flare on June 22 2015. We first perform a nonlinear force-free fields (NLFFFs) extrapolation to derive three-dimensional (3D) magnetic fields based on time series of observed photospheric magnetic fields. The NLFFFs well describe an observed sigmoidal structure with the shape of a double arc magnetic configuration. Next, we examine three possible instabilities (kink, torus, and double arc) to investigate how the M6.5 flare is triggered in the double arc loops. Consequently, the double arc loops are stable against kink and torus instabilities, but possibly unstable against the double arc instability before the flare occurrence. Finally, we discuss a probable scenario for the M6.5 flare.