• 천문학논총
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• 제30권2호
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• pp.489-490
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• 2015

We present population synthesis models for the calcium II triplet (CaT), currently the most popular metallicity indicator, based on high-resolution empirical spectral energy distributions (SEDs). Our new CaT models, based on empirical SEDs, show a linear correlation below [Fe/H] ~ -0.5, but the linear relation breaks down in the metal-rich regime by converging to the same equivalent width. This relation shows good agreement with the observed CaT of globular clusters (GCs) in NGC 1407 and the Milky Way. However, a model based on theoretical SEDs does not show this feature of the CaT and fails to reproduce observed GCs in the metal-rich regime. This linear relation may cause inaccurate metallicity determination for metal-rich stellar populations. We have also confirmed that the effect of horizontal-branch stars on the CaT is almost negligible in models based on both empirical and theoretical SEDs. Our new empirical model may explain the difference between the color distributions and CaT distributions of GCs in various early-type galaxies. Based on our model, we claim that the CaT is not a good metallicity indicator for simple stellar populations in the metal-rich regime.

• 환경영향평가
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• 제9권1호
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• pp.1-11
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• 2000

An environmental geochemical survey of heavy metal distribution in marine surface sediments around the ocean of Samcheonpo coal-fired power plant was conducted to investigate the possibility of coal-ash leakage from ash pond and the associated heavy metal pollution in sedimental deposits due to the operation of the coal-fired power plant. The X-Ray Diffractometry (XRD) analysis showed that the main leakage point of coal-ash was limited to a single site of the first ash pond. It also appeared that the amounts of organic carbon and metal elements were positively correlated to the grain size distribution, and that Co, Cr, Cu, Fe, Ni, and Zn were bounded to organic ligands. However, the distributions of Cd, Hg, and Mn did not have any significant correlation with the sediment grain size and organic matters. In particular, the distribution of Cd appeared to be affected by the concentration of the carbonate materials in the study area.

• 센서학회지
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• 제21권2호
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• pp.83-89
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• 2012

A simple array of metal-insulator-metal capacitive elements was proposed for a potential application in humidity sensing platforms. We fabricated meso-scale sensors with different sizes(large-size: $2.7{\times}2.7mm^2$ ; mid-size: $1.5{\times}1.5mm^2$ ; small-size: $0.7{\times}0.7mm^2$) and characterized the performance of each design. Polyimide films were utilized as a humidity-sensitive layer. Capacitance changes of the polyimide layer were measured with respect to water absorption. The device showed sensitivity in the full range of relative humidity (RH) with excellent linearity(correlation coefficient > 0.994). This array structure exhibits unique advantages including easy fabrication process, high batch productivity, and high structural compatibility with various substrate materials. It is anticipated that this device structure will be potentially useful in unique applications including mapping spatial humidity variations over a meso-scale area and implementing flexible humidity sensing element arrays.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.152-152
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• 2013

Mechanism of energy conversion from chemical to electrical during exothermic catalytic reactions at the metal surfaces has been a fascinating and crucial subject in heterogeneous catalysis. A metal-semiconductor Schottky nanodiode is novel device for direct detection of chemically induced hot electrons which have sufficient energy to surmount the Schottky barrier. We measured a continuous chemicurrent during the hydrogen oxidation under of 760 Torr of O2 and 6 Torr of H2 by using Pt/Si and Pt/TiO2 nanodiodes at reaction temperatures and compared the chemicurrent with the reaction turnover rate. The thermoelectric current was measured by carrying out an experiment under O2 condition for elimination of the background current. Gas chromatograph and source meter were used for measurement of the chemical turnover rate and the chemicurrent, respectively. The correlation between the chemicurrent and the chemical turnover rate under hydrogen oxidation implies how hot electrons generated on the metal surface affect hydrogen oxidation.

• 한국환경농학회지
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• 제8권1호
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• pp.1-6
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• 1989

사과잎중(中)의 중금속함량(重金屬含量)을 측정하고 과수원토양과 사과잎중(中)의 중금속함량간(間)의 상관관계(相關關係)를 규명하기 위해서 우리나라 58개 과수원에서 채취한 사과잎 시료 중(中) Cu, Cd 및 Pb을 분석(分析)하여 다음과 같은 결과를 얻었다. 1. 사과잎중(中)의 중금속 평균함량은 Cu 26,44 (6.23-182.85) ppm, Cd 0.34 (0.07-0.61) ppm, pb 9.47(0.00-225.50) ppm 이었다. 2. 토양(土壤)과 사과잎중(中)의 중금속함량간(間)의 상관관계 분석(分析)에서 Cu와 Pb은 유의성(有意性)있는 정(正)의 상관을 보였고, Cd은 유의성은 없었다. 또한 사과 두 품종(品種) 국광과 홍옥 및 기타품종을 분류 비교한 결과 품종간의 차이는 인정되지 않았다. 3.토양과 사과잎중(中)의 중금속함량간의 상관관계를 조사한 결과 $IN\;NH_4\;OAC$ (pH 7.0) 침출액 보다는 0.1N HCl 침출액을 토양침출액으로 사용하는 것이 더욱 높은 유의성있는 정(正)의 상관을 보여서 0.1N HCl이 더 적합한 것으로 밝혀졌다.

• 한국환경생태학회지
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• 제22권3호
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• pp.260-267
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• 2008

본 연구는 경남 산림지역의 산성강하물과 토양 화학적 특성의 관련성 조사를 위하여 수행하였다. 토양 pH는 평균 4.40이었으며, 가장 높은 조사구는 밀양 산내 조사구로 pH 5.02였고, 가장 낮은 조사구는 pH 4.08의 남해 서면이었다(p<0.05). 산림토양내 유기물, 유효인산, 칼륨, 칼슘, 마그네슘, 양이온치환용량(CEC)은 지역별 유의차가 있었다(p<0.05). 산림토양내 중금속 함량은 납이 평균 3.86mg/kg이었고, 거제 신현이 9.87mg/kg으로 가장 높았으며, 밀양 산내가 0.86mg/kg으로 가장 낮았다(p<0.05). 토양의 화학적 특성과 강우산도의 상관은 토양 $pH(r=0.7826^{**})$, 칼슘 $(r=0.6278^*)$, 마그네슘$(r=0.5841^*)$, 양이온치환용량$(r=0.6341^{**})$, 카드뮴$(r=0.5995^*)$과 정의 상관이었고, 납$(r=-0.5283^*)$은 부의 상관이었다. 대기 중의 $SO_2$, 농도와 상관은 토양 pH$(r=-0.6796^{**})$, 칼슘$(r=-0.5810^*)$, 마그네슘$(r=-0.5522^*)$, 양이온치환용량$(r=-0.5905^*)$과 부의 상관이었다. 대기 중의 $NO_2$, 농도와 상관은 유기물$(r=0.6208^*)$, 칼륨$(r=0.5380^*)$과 정의 상관이었다. 따라서 강우산도 및 대기 중의 $SO_2$는 토양의 산성화에 영향을 미치는 것으로 사료되며, 그리고 토양 내 중금속 함량에 영향을 미치는 것은 Cd와 Pb함량과 관련성이 있으며, 그 외 중금속의 영향은 없었다.

• Safety and Health at Work
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• 제3권1호
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• pp.31-42
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• 2012

Objectives: The objectives of this study were to determine the psychological fatigue and analyze muscle activity of production workers who are performing processes jobs while standing for prolonged time periods. Methods: The psychological fatigue experienced by the workers was obtained through questionnaire surveys. Meanwhile, muscle activity has been analyzed using surface electromyography (sEMG) measurement. Lower extremities muscles include: erector spinae, tibialis anterior, and gastrocnemius were concurrently measured for more than five hours of standing. Twenty male production workers in a metal stamping company participated as subjects in this study. The subjects were required to undergo questionnaire surveys and sEMG measurement. Results: Results of the questionnaire surveys found that all subjects experienced psychological fatigue due to prolonged standing jobs. Similarly, muscle fatigue has been identified through sEMG measurement. Based on the non-parametric statistical test using the Spearman's rank order correlation, the left erector spinae obtained a moderate positive correlation and statistically significant ($r_s$ = 0.552, p < 0.05) between the results of questionnaire surveys and sEMG measurement. Conclusion: Based on this study, the authors concluded that prolonged standing was contributed to psychological fatigue and to muscle fatigue among the production workers.

• 천문학회보
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• 제38권2호
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• pp.37.2-37.2
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• 2013

Recently it turns out that simple-looking elliptical galaxies and lenticular galaxies are more complex and intriguing than expected. One of the most surprising and intriguing findings in extragalactic studies during the last two decades is a discovery that color distribution of the globular clusters in these galaxies is bimodal, suggesting that there are two subpopulations: blue and red globular clusters. We present a determination of the two-dimensional shape parameters of the blue and red globular cluster systems (GCSs) in a large number of bright elliptical galaxies and lenticular galaxies. The position angles of both and red GCSs show a correlation with those of the stellar light distribution, showing that the major axes of the GCSs are well aligned with those of their host galaxies. However, the shapes of the red GCSs show a tight correlation with the stellar light distribution as with the rotation property of their host galaxies, while the shapes of the blue GCSs do much less. These provide clear geometric evidence that the origins of the blue and red globular clusters are distinct and that these galaxies may have dual halos: a blue (metal-poor) halo and a red (metal-rich) halo. These two halos show significant differences in metallicity, structure, and kinematics, indicating that they are formed in two distinguishable ways. The red halos might have formed via dissipational processes with rotation, while the blue halos are through accretion.

• 소성∙가공
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• 제27권2호
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• pp.115-122
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• 2018

Most domestic and international standards on the forming limit diagram (FLD) including ISO 12004-2, use a 'position-dependent method,' which determines the forming limit from a strain distribution measured on the specimen after necking or fracture. However, the position-dependent method has inherent problems such as the incidence of asymmetry of a strain distribution, the estimation of missing data near fracture, the termination time of test, and the deformation due to the new stress equilibrium after a fracture, which is blamed for causing sometimes a significant lab-to-lab variation. The 'time-dependent method,' which is anticipated to be a new international standard for evaluating the forming limit, is expected to greatly improve these intrinsic disadvantages of the position-dependent method. It is because the time-dependent method makes it possible to identify and accurately determine the forming limit, just before the necking point from the strain data as continuously measured in a short time interval. In this study, we propose a new time-dependent method based on a Gaussian fitting of strain acceleration with the introduction of 'normalized correlation coefficient.' It has been shown in this study that this method can determine the forming limit very stably and gives a higher value, which is in comparison with the results of the previously studied position-dependent and time-dependent methods.

• 대한한의학방제학회지
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• 제24권2호
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• pp.71-79
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• 2016

Objectives : To verify the equivalence between Atractylodis Rhizoma Alba herbal prescription(HP-ARA) and Atractylodis Rhizoma Alba herbal sub stance(HS-ARA). Methods : Safety tests by microbial regulation and heavy metal analysis (total heavy metal, Pb, As) and a stability test by long term shelf test for HP-ARA according to notification of the Ministry of Food and Drug Safety were carried out. Then, multi component profile of HP-ARA and HS -ARA were analyzed by HPLC. Results : The safety and stability of HP-ARA confirmed by several tests. Correlation coefficient of equivalence of HP-ARA and ARA-HS showed 0.992. Conclusion : Based on this result of equivalence between HP-ARA and HS-ARA, HP-ARA can substitute HS-ARA used to make herbal medicines (herbal decoction, pills and powder).