• 환경위생공학
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• 제7권1호
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• pp.87-94
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• 1992

In order to investigate the content of heavy metals in soil according to vertical profiles, 72 soil samples were collected from 4 sampling sites : Ulchiro-2 ga, Dugdo, Sungnaedong, and Amsa- dong. The content of mercury was measured by a mercury analyzer and those of lead, copper and zinc were measured by an atomic absorption spectrophotometer. From the results of this study, it was shown that the content of heavy metals decreased gradually from the surface soil to the 2 m- depth soil. But, there was no difference in the contents of the heavy metals in the 3m, the 4m and the 5m-depth soil.

• 통합자연과학논문집
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• 제1권1호
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• pp.54-57
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• 2008

This report examines the variation on structural properties of $SnO_2$ thin films. TEM studies shows some of the interfaces to be atomically faceted. Secondary X-ray photoelectron Spectroscopy Analysis(XPS) depth profiles show that films have a uniform composition along the depth.

• Design & Manufacturing
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• 제17권4호
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• pp.24-32
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• 2023

In this study, we introduce research aimed at minimizing machining errors without compromising productivity by compensating for the machining errors caused by tool deformation. Our approach experimentally establishes the direct correlation between cutting depth and machining error, and creates predictive models using mathematical functions. This method allows for the prediction of compensated cutting depths to obtain the desired cutting profiles, thereby maximizing the compensation of machining errors in the cutting process.

• 한국진공학회지
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• 제10권2호
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• pp.225-233
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• 2001

Oxygen flooding을 이용한 Secondary ion Mass Spectrometry(SIMS) 분석에 있어서 표면에 산화막이 있을 때 발생하는 SIMS depth profile의 왜곡현상에 대한 원인을 분석하고 이를 보정하였다. 이러한 왜곡현상은 표면 산화막에서와 Si 매질에서의 sputter rate이 다른 데서 발생하는 깊이 보정 오류와 상대감도인자(relative sensitivity factor, RSF)가 다른 데서 발생하는 농도보정 오류로부터 발생됨이 밝혀졌다. 깊이보정 오류를 바로잡기 위하여 $N^a+$ 이온을 산화막과 Si 매질의 계면에 대한 marker로 사용하였으며 산화막 두께는 SEM 및 XPS로 측정하였다. 산화막과 Si 매질에서의 sputter rate 및 RSF의 차이는 주로 oxygen flooding이 유발한 산화막 형성시의 부피팽창에 의한 것으로 해석되었으며 이를 보정한 depth profile은 oxygen flooding없이 분석한 경우와 거의 동일한 결과를 보여주었다.

• 한국생산제조학회지
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• 제25권1호
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• pp.83-88
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• 2016

Because of the increasing tool cost for cutting hard-to-cut materials, abrasive water jet (AWJ) milling recently has been regarded as a potential alternative machining method. However, it is difficult to control the depth and width of cut in AWJ milling because they vary depending on many AWJ cutting parameters. On 27 conditions within a limited range of pressure, feed rate, and abrasive flow rate, AWJ cutting was conducted on titanium, and depth profiles were measured with a laser sensor. From the depth profile data, depth and width of cut were acquired at each condition. The relationships between depth and parameters and between width and parameters were derived through regression analysis. The former can provide proper cutting conditions and the latter the proper pick feed necessary to generate a milled surface. It is verified that pressure mostly affects depth, whereas abrasive flow rate mostly affects width.

• 한국해양공학회지
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• 제25권4호
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• pp.23-27
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• 2011

This experimental study was performed to find rpms of the impeller and the surface flow accelerator to make a uniform velocity vertical distribution in the circular water channel. PIV technique was employed to measure the water velocity profiles into the water depth from the free surface. The number of instantaneous velocity profiles was decomposed into mean and turbulence velocity components, and the distribution of velocity fluctuation and turbulence intensity were computed for each experimental condition. From these results, the velocity uniformity was quantitatively determined to present the flow quality in the measuring section of the circular water channel. It has been shown that the proper operation of the surface flow accelerator would make the uniform velocity profiles and reduce the velocity fluctuation near the free surface.

• 자원환경지질
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• 제40권6호
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• pp.751-759
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• 2007

황해 군산분지의 지하 지질구조를 파악하기 위하여 인공위성 해면고도계 중력자료를 이용하여 파워 스펙트럼 분석(power spectrum analysis) 방법으로 밀도 불연속면의 평균 깊이를 계산하였다. 계산 결과에 의하면 군산분지를 포함한 본 연구지역에서는 각각 -1.1km, -3.4km, -9.1km 그리고 -31.0km의 평균 깊이를 가지는 밀도 불연속면이 검출되었다. -1.1km 평균 깊이의 밀도 불연속면은 본 연구지역의의 탄성파 단면에서 관찰되는 왕복 주시 1초 부근에서 나타나는 광역 부정합면으로 해석되었고, -3.4km 평균 깊이의 밀도 불연속면 또한 탄성파 단면에서 인지되는 음향기반암 상부면과 일치하는 것으로 해석되었다. -9.1km 평균 깊이의 밀도 불연속면은 본 연구지역의 시추공 자료, 탄성파 단면, 광역 지질 등을 고려하여 화성기원 기반암의 상부면으로 해석하였다. 이는 본 연구지역의 음향 기반암층은 기존의 연구에서 고려 대상이 되지 않았던 퇴적암으로 이루어져 있음을 의미한다. -31.0km의 평균 깊이를 가지는 밀도 불연속면은 일반적인 대륙지각의 평균 두께와 유사한 값을 보이므로 모호면으로 해석하였다. 화성기원 기반암 상부면으로 해석된 -9.1km 평균 깊이의 밀도 불연속면의 검출은 군산분지의 석유 가스 부존 가능성에 관한 연구에 있어 기존의 연구보다 심부층(음향 기반암층)에 대한 연구가 필요함을 시사하였다.

• 분석과학
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• 제10권2호
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• pp.105-113
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• 1997

본 실험은 경남 일광 지역의 한 폐광의 토양에 함유된 중금속의 함량을 연구한 것이다. 세 지점을 선택하여, 각 지점마다 30cm씩 210 또는 240cm까지 굴착하였다. 각 시료는 풍건한 후 왕수분 해법으로 추출한 다음, 유도결합쌍 플라즈마 원자방출분광법(ICP-AES)으로 정량분석하였다. Zn, Pb, Cr, Cd, Cu, Mn 및 Fe를 대상으로 분석하였고, Pb, Cd 및 Zn의 함유량의 최대값은 $(4.6{\pm}0.1){\times}10^3$, 9.4(${\pm}3.6$) 및 $(2.7{\pm}0.1){\times}10^2{\mu}g/g$으로 각각 나타났다. 1번 지역의 평균 pH값은 3.2, 2번 지역은 2.6, 그리고 3번 지역은 2.8로 나타났다. 그 값들은 4.9로 나타난 표준 시료 토양의 pH값에 비해 현저히 낮다. 각 시료 채취 지점에서, 중금속의 최대값은 30cm부터 60cm 깊이 사이에서 관찰되었다. Zn, Cd, Pb 및 Cu의 깊이에 따른 중금속 함량들은 분포된 경향이 비슷하게 나타나지만, Fe, Cu 및 Mn은 앞의 중금속들과는 분포된 경향이 다르게 나타났다.

• Smart Structures and Systems
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• 제16권4호
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• pp.667-681
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• 2015

The scour induced by strong currents and wave action decreases the embedded length of monopiles and leads to a decrease of their structural stability. The objective of this study is the development and consideration of scour-monitoring techniques for offshore monopile foundations. Tests on physical models are carried out with a model monopile and geo-materials prepared in a cylindrical tank. A strain gauge, two coupled ultrasonic transducers, and ten electrodes are used for monitoring the scour. The natural frequency, ultrasonic reflection images, and electrical resistivity profiles are obtained at various scour depths. The experimental results show that the natural frequency of the model monopile decreases with an increase in the scour depth and that the ultrasonic reflection images clearly detect the scour shape and scour depth. In addition, the electrical resistivity decreases with an increase in scour depth. This study suggests that natural frequency measurement, ultrasonic reflection imaging, and electrical resistivity profiling may be used as effective tools to monitor the scour around an offshore monopile foundation.

• 한국진공학회지
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• 제5권3호
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• pp.218-222
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• 1996

STrained layers and strain depth profile of high dose As ion implanted (100) si wafer annealed at various temperatures have been investigated by means of X-ray double crystal diffractometry (X-ray DCD). The results obtained by x-ray rocking curve analysis showed a defect layer at the original amorphous /crystalline interface of 1400$\AA$ depth. In addition arsenic ion concentrtion profiles and defect distributions in depth were obtained by the SIMS and TRIM -code simulation . the positive strain depth profile determined from the rocking curve analysis were only presented under 0.14 $\mu$m from the surface for samples ananelaed at $600^{\circ}C$. The results was shown that the thickness of amprphous layer is 0.14 $\mu$m indirectry, and it was good agreement with the TRIM -Code simulation. Additionally, it could be thought that the positive strain have been affected residual intersitial atoms under the amorphous/crystalline interface formed by ion implantation.