• 천문학회보
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• 제35권2호
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• pp.84.2-84.2
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• 2010

Radial changes of stellar population within the Galactic globular clusters have been reported in many spectroscopic and photometric studies. We present new integrated spectroscopic data for 24 Galactic globular clusters and have measured line indices within various aperture sizes. Radial gradients have been investigated for the Balmer lines and metal lines (Mgb). Our results show an increase in the strength of the Balmer lines toward the centres in some clusters including NGC7078, NGC7089, and NGC6934, in which colour gradients also have been detected previously. However, some other clusters show little trend or even an increase toward the outskirt in the Balmer lines. Metal sensitive lines generally have an anti-correlation with the Balmer lines. We discuss possible stellar populations being responsible for the radial change in line indices.

• 한국물환경학회지
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• 제25권4호
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• pp.560-567
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• 2009

Treated or untreated wastewater may be a major source of refractory organic matters (R-OM) in drinking water sources. For this study, spectroscopic characteristics of wastewater OM were investigated using the samples from 20 wastewater treatment plants, which are located at the upstream of the lake Paldang, to suggest a estimate index for R-OM in wastewater. R-OM was quantified by measuring total organic carbon (TOC) concentration of the wastewater samples remaining after 28-day dark incubation. Among the traditional OM indices such as chemical oxygen demand (COD) and initial TOC, CODMn showed the lowest correlation coefficients with R-TOC of the samples. The ratios of carbonaceous biochemical oxygen demand (CBOD) to $COD_{Cr}$ had a better correlation with the percent distribution of R-OM than $BOD/COD_{Cr}$ ratios. terrestrial humic-like fluorescence (THLF) exhibited the highest correlation coefficient with R-TOC among the indices obtained from the synchronous fluorescence spectra of the samples. Milori index, one of the humification indices, showed a good correlation with the percent distribution of wastewater. This study demonstrated that fluorescence properties might be a better indices to estimate the concentrations and the distributions of wastewater OM compared to the specific UV absorbance (SUVA) values. Some useful formulas based on OM spectroscopic characteristics were finally suggested to predict R-OM in wastewater.

• 한국물환경학회지
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• 제32권1호
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• pp.98-107
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• 2016

This study examined the effects of environmental conditions and the presence of refractory organic matter on oxidation rates of total organic carbon (TOC) measurements based on high temperature combustion and ultraviolet-sulfate methods. Spectroscopic indices for prediction of oxidation rates were also explored using the UV spectra and fluorescence excitation-emission matrix (EEM) of humic acids. Furthermore, optimum TOC instrument conditions were suggested by comparing oxidation rates of a standard TOC material under various conditions. Environmental conditions included salts, reduced ions, and suspended solids. Salts had the greatest influence on oxidation rates in the UV-sulfate method. However, no effect was detected in the high temperature combustion method. The UV-sulfate method showed lower humic substance oxidation rates, refractory natural organic matter, compared to the other methods. TOC oxidation rates for the UV-sulfate method were negatively correlated with higher specific-UV absorbance, humification index, and humic-like EEM peak intensities, suggesting that these spectroscopic indices could be used to predict TOC oxidation rates. TOC signals from instruments using the UV-sulfate method increased with increasing chamber temperature and increasing UV exposure durations. Signals were more sensitive to the former condition, suggesting that chamber temperature is important for improving the TOC oxidation rates of refractory organic matter.

• 생태와환경
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• 제56권4호
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• pp.339-347
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• 2023

본 연구는 TOC/TN-IRMS를 이용하여 총 유기탄소 및 총 질소 안정동위원소 분석법을 연구하였으며, 수환경 중저농도 시료에서도 분석이 가능하게 시스템을 구축하였다. 수생태계로 유입되는 다양한 유기탄소 기원을 파악하기 위하여 형광지표와 δ¹³C-DOC 안정동위원소비를 활용한다면 효율적인 수질 관리를 위한 해석기능을 제공할 것이며, 추후 유역 오염원의 대표값(end member)의 지속적인 조사를 통하여 자료구축이 이루어져야 할 것이다.

• 한국광학회지
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• 제12권6호
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• pp.472-478
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• 2001

가변입사각 분광타원법(Variable Angle Spectroscopic Ellipsometry)을 사용하여 유기발광소자(OLED)의 발광층인 유기박막 의 광학상수와 두께를 결정하였다. 광투과영역에서 모델링분석으로 박막의 평균두께와 굴절률 분산식을 결정하고, 광흡수영역으로 확장하여 유기막의 다층구조, 각 층의 두께와 밀도 그리고 각 파장에서의 복소굴절률을 결정하였다. 분광광도계를 사용하여 구한 투과율 스펙트럼을 가변입사각 분광타원법을 사용하여 결정한 다층구조 및 복소굴절률로 계산한 투과율 스펙트럼과 비교하여 분석의 정확성을 확인하였다.

• 천문학논총
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• 제8권1호
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• pp.17-31
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• 1993

In order to check whether the 4-degree objective prism spectra can be used for deep spectroscopic studies of galactic structure, we measured the Rose(1984)'s seven indices between 3500 A and 4400 A for 19 Hyades stars on the Kiso Schmidt prism plate, K3496. By comparing the $4^{\circ}$-indices with those of Rose(1984), we have found that $H{\delta}/FeI$, $H{\gamma}/4325$, and P(3912)/P(CN) measured on the 4-degree prism spectra, are still useful for the derivation physical parameters.

• 천문학회보
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• 제35권2호
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• pp.31.1-31.1
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• 2010

We present a spectroscopic study of the globular clusters (GCs) in the giant elliptical galaxy (gE) NGC 4636 in the Virgo cluster. Line indices of GCs in NGC 4636 are measured from the integrated spectra obtained with Faint Object Camera and Spectrograph (FOCAS) on the Subaru Telescope. We derive the [Fe/H] of the GCs in NGC 4636 using Brodie & Huchra (1990) method. The [Z/H], age, and alpha-element of the GCs are obtained from the comparison of the Lick line indices with the SSP model grid. We investigate the distribution and radial variation of the metallicity, age, and alpha-element of NGC 4636 GCs. The metallicity distribution of NGC 4636 GCs shows a bimodality. The chemical properties of these GCs show little radial variation. These results will be discussed with regard to the formation and evolution of NGC 4636.

• 한국표면공학회지
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• 제29권5호
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• pp.556-562
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• 1996

Carbon nitride (CN) films were synthesized on silicon substrates by a combined ion-beam and laser-ablation method under various conditions; ion-beam energy and ion-beam current were varied. Raman spectroscopy and spectroscopic ellipsometry (SE) were employed to characterize respectively the structural and the optical properties of the CN films. Raman spectra show that all the CN films are amorphous independent of the ion-beam current and the ion-beam energy. Refractive indices, extinction coefficients and optical band gaps which were determined from the measured SE spectra exhibit a significant dependence on the synthesis conditions. Especially, the decrease of the refractive indices and the shrinkage of the optical band gap is noticeable as the ion-beam current and/or the ion-beam energy increase.

• 한국광학회:학술대회논문집
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• 한국광학회 2004년도 하계학술발표회
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• pp.276-277
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• 2004

• 한국진공학회지
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• 제17권2호
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• pp.138-147
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• 2008

RF 스퍼터링 시스템을 이용하여 $SiO_2/TiO_2/ZrO_2$ 광대역 반사방지막을 단계별로 제작하였고, 분광타원계와 $UV-V_{is}$ 분광광도계를 이용하여 박막의 두께, 굴절률 및 투과율 스펙트럼을 300$\sim$900nm의 파장 영역에 걸쳐 측정 및 분석하였다. 측정 및 분석된 박막의 두께, 굴절률 및 투과율 스펙트럼을 설계값과 비교 평가한 결과 각층의 두께, 굴절률의 차이에 따른 투과율의 변화를 분석할 수 있었고, 박막의 두께보다는 굴절률과 굴절률의 분산형태가 투과율의 변화에 더 크게 기여함을 알 수 있었다.