• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.369-369
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• 2011

양자점 감응형 태양전지는 가시광 영역을 흡수, 이용할 수 있는 광감응 물질로 무기물 양자점을 사용하며, 이 경우 나노미터 크기의 무기물 양자점으로 인한 양자제한 효과 (quantum confinement effect)에 의해 양자점의 사이즈 조절 만으로 밴드갭을 조절할 수 있어 광학적 특성 조절이 용이하며, 하나의 광자를 흡수하여 두개 이상의 전자-정공쌍을 만들 수 있는 (multiple exciton generation) 가능성이 있어 기존 태양전지가 가지는 이론적 한계효율(Shockley-Queisser limit)을 뛰어넘을 수 있다. 본 연구에서는 양자점 및 염료 감응형 태양전지분야에서 가장 많이 사용되고 있는 TiO2 다공성 필름이 아닌, ZnO 나노선 구조를 이용하여 양자점 감응형 태양전지를 제작하였다. ZnO의 경우 TiO2보다 높은 전자이동도를 가지며, 나노선 구조가 바닥전극까지 수직 연결된 1차원의 전자전달경로를 제공하여 결과적으로 광전자 포집에 유리하다. 또한, CdS, CdSe 양자점을 동시에 사용하여 광흡수 범위를 가시광 전 영역으로 확장하였으며, 계단형 밴드구조를 통해 광전자-정공 분리 및 포집을 용이하게 하였다. 더 나아가 전해질의 조성, 나노선의 길이 등 다양한 부분을 조절하면서 각 변수가 소자의 효율에 미치는 영향을 관찰하였다.

• Journal of Environmental Science International
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• v.26 no.7
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• pp.847-858
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• 2017

For 26 soil series distributed more than 1% among 63 soil series in Jeju Island, natural uncultivated soil samples were collected. For these soils, the chemical speciation of eight heavy metals (Cd, Cr, Cu, Mn, Ni, Pb, V, and Zn) was examined. Further, the Plant Bioavailability (PB) and Mobility Factor (MF) of these heavy metals were evaluated using Tessier's 5-step sequential extraction method (exchangeable, carbonate, reducible (bound to Fe/Mn oxides), oxidizable (bound to organic matter), and residual fraction). The main form present was residual fraction for Cd and Zn; residual and oxidizable fractions for Cr, Cu, Ni, and Pb; reducible fraction for Mn; and carbonate fraction for V. The average plant availability and average mobility factor were found to be V (57.37%) > Zn (12.49%) > Cd (11.76%) > Cu (11.19%) > Pb (9.37%) > Cr (9.09%) > Mn (3.13%) > Ni (2.63%), and Mn (61.04%) > V (59.94%) > Zn (31.54%) > Cd (17.65%) > Cr (15.66%) > Ni (13.89%) > Pb (13.80%) > Cu (13.53%), respectively.

• Bulletin of the Korean Chemical Society
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• v.31 no.12
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• pp.3611-3616
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• 2010

Five new 4- or 8-substituted-7-hydroxycoumarin derivatives (1-5) were synthesized as fluorescent sensors for metal ions. Fluorescent changes and selectivity for metal ions were compared based on the introduction of different ligands and/or testing with different substitution positions of 7-hydroxycoumarin in aqueous solution. Especially, probes 2, 3 and 5 displayed large fluorescence enhancements with $Zn^{2+}$ and $Cd^{2+}$. Probes 2 and 3 showed moderate selectivity for $Zn^{2+}$ over $Cd^{2+}$. On the other hand, probe 4 showed large fluorescence quenching effects upon the addition of $Ag^+$ and $Hg^{2+}$.

• The Korean Journal of Financial Studies
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• v.7 no.1
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• pp.153-170
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• 2001

선물의 만기효과는 선물의 만기일에 가까워질수록 선물가격의 변동성이 증가하는 현상으로 사무엘슨 효과라고도 하는데, 이는 선물가격의 행태를 이해하고 투자전략과 헤지전략을 수립하는 데 매우 중요하다. 그 동안 미국을 비롯한 선진국에서 이에 대한 많은 실증연구가 있었다. 본 연구에서는 KSE의 KOSPI 200 지수선물과 KOFEX의 CD 금리선물, 국채선물, 미국달러선물, 금선물을 대상으로 선물가격의 만기효과를 검정하였으며, 그 결과는 다음과 같다. 먼저, Conover 제곱순위검정과 F-검정의 결과, KOSPI 200 지수선물에서는 만기일에 가까워질수록 변동성이 증가하는 만기효과가 나타난 반면에 CD 금리선물과 국채선물에서는 만기일에 가까워질수록 변동성이 오히려 감소하는 역 만기효과가 나타났다. 그러나 미국달러선물과 금선물에서는 만기효과를 판단하기가 어려웠다. 나아가, 연도효과를 통제한 회귀분석 결과, KOSPI 200 지수선물에서는 5% 수준에서 유의한 만기효과가 나타났다. 이는 금융선물에서 만기효과를 처음으로 발견한 Milonas(1986)의 연구와 일치하지만, Chen-Duan-Hung(1999)의 연구와는 상반된다. 그리고 CD 금리선물에서는 1% 수준에서, 그리고 국채선물에서는 5% 수준에서 각각 유의한 역 만기효과가 나타났으며, 미국달러와 금 선물에서는 만기효과가 나타나지 않았다. 또한 CD 금리선물을 제외한 KOSPI 200 지수, 국채, 미국달러 및 금 선물에서 모두 1% 수준에서 유의한 연도효과가 나타났다. 이는 Milonas-Vora(1985), Khoury-Yourougou(1993), Galloway-Kolb(1996) 등의 연구와 일치한다.

• Analytical Science and Technology
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• v.10 no.1
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• pp.31-34
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• 1997

Barium titanyl oxalate which is a precursor of barium titanate has been precipitated at pH 4~5 by a rapid addition of aqueous titanyl oxalate solution to artificial environmental water samples containing equivalent weight of $Ba^{2+}$ ions. Quantitative recoveries of $Cd^{2+}$ and $Pb^{2+}$ from the water samples has been confirmed and found to be usable as a possible method of preconcentration for their determination.

• Journal of Korea Foundry Society
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• v.25 no.6
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• pp.226-232
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• 2005

Contact material is widely used in the field of electrical parts. Ag-CdO material has a good wear resistance and stable contact resistance. In order to establish optimizing heat treatment condition, rolling temperature and oxidation process, we studied the microstructure of Ag-CdO material with various conditions. The experimental procedure were melting using high frequency induction, heat treatment, rolling and internal oxidation. And we experimented on difference process, Post-oxidaion. In this study, we obtained the optimizing heat treatment condition was $700^{\circ}C$ for 15 min. and the optimizing rolling temperature was $730^{\circ}C$. In investigation of the microstructure of oxidized material, coarse oxide and depleted oxidation layer existed. The hardness was average Hv 70. When we used Post-oxidation, oxides were finer than prior process and depleted oxidation layer did not exist. The hardness of Post-oxidation material was average Hv 80. And the optimizing rolling temperature was $800^{\circ}C$.

• Proceedings of the Ginseng society Conference
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• 2002.10a
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• pp.288-297
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• 2002

In this paper, we present evidence that the red ginseng from Panax ginseng C.A. Meyer inhibits the recurrence of advanced gastric cancer and shows immunomodulatory activities during postoperative chemotherapy. Flow cytometric analyses for peripheral T-lymphocyte subsets showed that the red ginseng powder restored CD4 levels to the initial preoperative values during postoperative chemotherapy. Depression of CD3 during postoperative chemotherapy was also inhibited by the red ginseng powder ingestion. This study demonstrated a 5-year disease free survival and overall survival rate that was significantly higher in patients taking the red ginseng powder during postoperative chemotherapy vs. control $(68.2\%\;vs.\;33.3\%,\;76.4\%\;vs.\;38.5\%,$ respectively, p<0.05). The mean value of serum IL-10 of the ginseng group was reduced progressively during the postoperative chemotherapy. The values of the ginseng group were close to that of the control group on postoperative months 3. These studies suggest that the red ginseng may have some immunomodulatory properties associated with CD3 and CD4 activity and interleukin 10 during postoperative chemotherapy and some potential of improving prognosis in patients with advanced gastric cancer.

• The korean journal of orthodontics
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• v.49 no.1
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• pp.32-40
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• 2019

Objective: Precise identification of landmarks on posteroanterior (PA) cephalograms is necessary when evaluating lateral problems such as facial asymmetry. The aim of the present study was to investigate whether the use of lateral (LA) cephalograms can reduce errors in landmark identification on PA cephalograms. Methods: Five examiners identified 16 landmarks (Cg, N, ANS, GT, Me, RO, Lo, FM, Z, Or, Zyg, Cd, NC, Ms, M, and Ag) on 32 PA cephalograms with and without LA cephalograms at the same time. The positions of the landmarks were recorded and saved in the horizontal and vertical direction. The mean errors and standard deviation of landmarks location according to the use of LA cephalograms were compared for each landmark. Results: Relatively small errors were found for ANS, Me, Ms, and Ag, while relatively large errors were found for N, GT, Z, Or, and Cd. No significant difference was found between the horizontal and vertical errors for Z and Or, while large vertical errors were found for N, GT, and Cd. The value of identification error was lower when the landmarks were identified using LA cephalograms. Statistically significant error reductions were found at N and Cd with LA cephalograms, especially in the vertical direction. Conclusions: The use of LA cephalograms during identification of landmarks on PA cephalograms could help reduce identification errors.

• IMMUNE NETWORK
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• v.23 no.2
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• pp.12.1-12.17
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• 2023

Ssu72, a dual-specificity protein phosphatase, not only participates in transcription biogenesis, but also affects pathophysiological functions in a tissue-specific manner. Recently, it has been shown that Ssu72 is required for T cell differentiation and function by controlling multiple immune receptor-mediated signals, including TCR and several cytokine receptor signaling pathways. Ssu72 deficiency in T cells is associated with impaired fine-tuning of receptor-mediated signaling and a defect in CD4⁺ T cell homeostasis, resulting in immune-mediated diseases. However, the mechanism by which Ssu72 in T cells integrates the pathophysiology of multiple immune-mediated diseases is still poorly elucidated. In this review, we will focus on the immunoregulatory mechanism of Ssu72 phosphatase in CD4⁺ T cell differentiation, activation, and phenotypic function. We will also discuss the current understanding of the correlation between Ssu72 in T cells and pathological functions which suggests that Ssu72 might be a therapeutic target in autoimmune disorders and other diseases.

• Bulletin of the Korean Chemical Society
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• v.33 no.5
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• pp.1517-1522
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• 2012

Anion effects on structures of $Cd^{II}$ complexes containing 2,2'-bipyridine (2,2'-bpy) ligands have been studied, and compared with $Zn^{II}$-(2,2'-bpy) complexes. For each anion, different structures have been obtained in both $Zn^{II}$-(2,2'-bpy) and $Cd^{II}$-(2,2'-bpy). Polymeric structures of $Cd^{II}$-2,2'-bpy complexes can be produced by hydrogen bonding interactions as shown in $Zn^{II}$-2,2'-bpy complexes. In addition, the bigger size of a $Cd^{II}$ ion gives higher coordination numbers forming variety of structures, and it makes that chlorides can act as bridging ligands to form a one-dimensional structure. The compound $\mathbf{5}$ catalyzed efficiently the transesterification of a variety of esters with methanol, while the rest of the compounds have displayed very slow conversions. In addition, the emission bands of complexes $\mathbf{1}$, $\mathbf{2}$, $\mathbf{4}$, and $\mathbf{6}$ are blue-shifted compared to the corresponding ligand 2,2'-bpy, whereas $\mathbf{3}$ and $\mathbf{5}$ showed the similar emission observed for the ligand.