• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.174.1-174.1
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• 2013

최근에 우수한 광학적 특성과 높은 화학적 안정성을 갖는 적황색 형광체 개발에 많은 노력이 경주되고 있다. 본 연구에서는 고상반응법을 사용하여 모체 결정 $YNbO_4$에 $Eu^{3+}$와 $Dy^{3+}$이온의 농도를 각각 체계적으로 치환 고용하여 발광 효율이 높은 적색과 황색 형광체를 제조하였다. 특히, $Eu^{3+}$와 $Dy^{3+}$이온의 농도를 달리하여 합성한 형광체 분말의 결정구조, 표면형상, 흡광과 발광 스펙트럼을 비교 분석하여 최적의 이온 농도를 조사하였다. 합성된 형광체 분말의 회절상은 $Eu^{3+}$와 $Dy^{3+}$이온의 함량비에 관계없이 모든 형광체 분말 시료는 약 $28,6^{\circ}$ 에서 최대값을 갖는 (021)면에서 발생하였고, 형광체 분말은 JCPDS #72-2077에 제시된 회절상과 일치하는 단사정계 결정 구조임을 확인 하였다. $Dy^{3+}$이온의 함량비가 0.01 mol에서 주 회절 피크의 세기는 최대이었으며, 함량비가 더욱 증가함에 따라 회절 피크의 세기는 점점 감소하였다. 이에 반하여, $Eu^{3+}$가 도핑된 형광체는 함량비가 0.15 mol일때 최대 회절피크가 관측되었다. $Dy^{3+}$이온이 도핑된 $YNbO_4$ 형광체의 경우에 두 종류의 흡광 스펙트럼이 관측되었다. 첫째는 약 267 nm를 피크로 하여 230~300 nm 영역에 걸쳐 폭넓게 분포하는 흡광 스펙트럼이고, 두 번째는 약 356, 393, 456 nm에 피크를 갖는 상대적으로 세기가 약하고 밴드폭이 좁은 흡광 스펙트럼이 관측되었다. $Eu^{3+}$이온이 도핑된 형광체 분말의 주 흡광 스펙트럼은 약 270 nm에 피크를 갖는 폭넓게 분포하는 전하전달 밴드이었다. $YNbO_4$ 형광체 분말의 발광 스펙트럼은 $Eu^{3+}$이온이 도핑된 경우에 620 nm에 강한 세기를 갖는 적색 발광이 관측되었고, $Dy^{3+}$이온이 도핑된 경우에는 580 nm에 최대 발광세기를 갖는 황색 발광 스펙트럼이 나타났다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4483-4488
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• 2010

In comparison with some other light sources, LED has merits such as long lifetime, pollution free, and high energy efficiency. Lately, due to development of LED with high brightness and capacity, LED, which has been applied in display system only, has applied in the field of lighting system. Driving current of power LED has to be controlled below the designed value. In this paper, half-bridge LLC series resonant converter, which has the current limiting function, has been described. Half-bridge LLC series resonant converter allows in relatively wide input voltage and output load range when compared to the other resonant converter. Also, it is possible to reduce a magnetic component, because leakage inductance of transformer is used as a resonant inductance. It has been validated by designing and testing 200[W] half-bridge LLC converter of DC24[V] output voltage for LED lamp driver, which includes a current limiting function and power factor correction(PFC) function.

• Journal of Korea Port Economic Association
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• v.25 no.3
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• pp.303-320
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• 2009

Korea has achieved a remarkable growth by pursuing externally-oriented growth policy since 1960s. That is, we imported raw materials and spare parts, manufactured them into products and exported them, which led to successful economic development. Therefore, our marine business has played an important roles as one of key industries. The development of marine business has contributed to efficient distribution and cost reduction in addition to production of added value and creation of employment creation, which improved external competitive power. In spite of economic importance of marine business, national perception on it is in general low and its developmental conditions are considerably poor. Therefore, this study aims to speculate the effect of Port-related business on regional economy using regional input-output tables.

• Korea journal of population studies
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• v.9 no.2
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• pp.107-128
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• 1986

본 연구의 목적은 노동력의 사회적 특성적인 면에 있어서 각기 다른 산업에 종사하는 노동력의 "누가" "어떻게" 변화해 가는가에 중점을 두면서 한국의 산업 각 부분간의 변천과정을 조사하는 데 있다. 이 연구에는 1960, 1970, 1980년에 실시된 한국 센서스 자료가 주로 사용되었다. 본 연구의 결과에 따르면 1960년과 1980년 사이의 한국의 산업 구조적인 면에 있어서의 급속한 변화를 보여주고 있다. 그러한 변화들은 주로 경제발전 정책과 더불어 농촌지역에서 도시지역으로의 인구이동에 기인된다고 하겠다. 예를 들면 1960년에 65%의 노동력이 1차 산업에 종사한 반면에 1980년에는 38.5%로 감소했고 이와는 대조적으로 1960년에 오직 8.7%의 노동력이 2차산업에 종사하던 것이 1980년에는 27.6%로 증가하였다. 3차 산업 역시 1960년에 23.8%에서 1980년에 33.9%로 10%의 증가를 보였다. 경제.발전이 이루어지는 과정에서 실업자들이나 잠재 실업자들이 경제활동에 참여할 수 있었기 때문에 경제구조 자체가 예전에 비해 더 안정이 되고 생활수준도 향상이 되었다고 하겠다. 이러한 결과는 부분적으로는 계속된 5개년 경제개발 계획에 기인된다고 할 수 있다. 경제발전 과정에서의 대도시로의 인구집중, 특히나 2차 산업과 3차 산업이 집중되어 있는 서울로의 인구집중은 주택, 교통, 범죄등 많은 문제를 낳고 있다. 동시에 도시지역에의 과잉 노동력의 존재와 농촌지역에는 특히나 농번기에 노동력 부족현상을 야기시키고 있다. 시간의 흐름에 따라 여성노동력의 비율, 전문직과 사무직 종사자, 그리고 서비스분야 종사자들의 비율이 증가하였는 데 비해 대부분의 다른 국가에서 처럼 한국에 있어서도 자영인의 비율은 경제발전 과정에서 감소하였다. 경제발전과 더불어 보다 전문화되고 조직화된 시장중심의 생산체제가 가구와 지역사회 중심의 생산기능을 흡수하므로서 많은 노동력이 임금 노동자가 되었다. 특히나 단순노동을 통한 많은 젊은 여성들을 고용하는 제조산업 분야에서 여성들이 낮은 임금과 과로 그리고 나쁜 작업환경으로 인하여 그들의 건강을 해치고 직업병을 유발할 가능성이 많다고 하겠다. 지난 20년에 걸친 급속한 정부 주도형의 경제발전은 노동력의 제 산업 간의 급속한 변천과 더불어 긍정적인 측면과 부정적인 측면을 모두 낳았다고 할 수 있겠다.측면을 모두 낳았다고 할 수 있겠다.

• Korea journal of population studies
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• v.35 no.2
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• pp.159-184
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• 2012

This study purports to analyze how individuals' labor market integration affect their transition to marriage. In doing so, I construct variables for job stability and continuity to represent labor market integration using labor force status and years of participation at the time of marriage and during the three years up to the point of marriage. In particular, I focus on differential effects of these labor market integration on the transition to marriage by cohorts: one for those who are likely to enter the labor market after the 1997 financial crisis and the other for those who are before the 1997 financial crisis. I used the Korean Labor and Income Panel Study and analyzed individuals aged above 18 in 2008. The main results are as follows. being currently employed and regular employment increases hazards of the first marriage for men but decreases them for women. long-term no-jobs decreases hazards of marriage for both women and men. long-term regular employment increases hazards of marriage for women but not for men at the statistically significant level. These effects vary by cohorts implying that recent economic and labor market instability deteriorated economic conditions for the youth making transitions to marriage.

• Journal of the Korean Regional Science Association
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• v.37 no.4
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• pp.3-19
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• 2021

This study examines changes in commercial space in Seoul from 1999 to 2016 by investigating operating periods of commercial businesses. This study finds that the characteristics of spatial changes in commercial districts are classified by the following two major points. First, the traditional CBD and Yeongdeung-po commercial districts show that both ages (survival duration) of operating commercial businesses and operating periods of market-exit businesses have changed to become longer than the average values of the two business types in Seoul. In contrast, the Gangnam and the Mapo commercial districts show that the operating periods of survived and closed commercial businesses have changed to become shorter over time. The difference suggests that survival-exit relations of businesses are closely related to the characteristics of each commercial district. In addition, this study shows that each commercial district has experienced dynamic changes in the intensity of commercial activities and the hierarchy of commercial space. Finally, this study indicates that public policies for commercial space should consider survival-exit dynamics of commercial activities in commercial districts.

• Korean Journal of Labor Studies
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• v.24 no.1
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• pp.229-260
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• 2018

Workaholism refers to a state in which work is the center of self, a state in which other life other than work is deemed worthless, and a state in which one feels that his or her life ends when things get lost. There are concerns that South Korea's work-centered institutions, cultures and long-time labor practices expose workers to workaholism. This study identifies the prevalence of workaholism and its risk factors among workers using a representative sample from Korean Labor and Income Panel Study. The results of empirical analysis of the wide range of workaholism showed that 7.0% of Korean workers were work-addicts. Male, workers working long hours, daily workers, employers, the self-employed were more likely to be work-addicts. Those who think that workload is high beyond regular working hours are more likely to be work-addicts. These results were also confirmed by regression analysis. It suggests that policies to shorten working hours and strengthen job and income stability can reduce the risk of workaholism and balance between work and life.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.2
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• pp.65-71
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• 2022

In the case of Mobile PKG Trend is in a situation where a decrease in Mold Top Margin is inevitable due to its miniaturization and high capacity product requirements. However, conventional laser marking technology has an average depth of deep, and when applied to narrow top margin products, PKG strength is expected to decrease due to overlapping processing, and reliability is reduced due to poor quality such as chip damage due to laser exposure. Therefore, we have secured the technology through research on low-depth laser marking solutions that can accommodate narrow top margin products. As a result of the evaluation of applicable technology application for PKG development products, it was verified that the marking depth decreased by 67% reduced and the PKG strength increased by 12%. Furthermore, the quality verification of Laser Damage that can occur through PKG Mechanical analysis was performed, and no Chip Damage defects were found. This ensured the stability of mass production application quality.

• Korean Journal of Social Welfare Studies
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• v.42 no.4
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• pp.137-163
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• 2011

The objective of this study is to examine the trend of real earnings for TANF leavers. Using administrative data in Wisconsin, this study tracks the 1998 TANF leavers over 7 years. Based on the cyclicality of real wage hypothesis, this study finds: First, although the average real quarterly earnings of TANF leavers have remained stable since their exits, there are substantial labor mobility among TANF leavers. Second, the panel data analysis shows that the real earnings of TANF leavers are significantly associated with local labor market conditions, which supports the hypothesis on the cyclicality of real wages. This study has policy implications that labor market conditions matter for the economic well-being of TANF leavers and the labor demand policies are needed for the economic security of TANF leavers after the exit.

• Journal of Korea Entertainment Industry Association
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• v.14 no.4
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• pp.289-303
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• 2020

The purpose of this study is to provide adequate datas on number of people who are in golf related field and also further expend that number for golf industry. The main stream of this study is to map out present golf related jobs and how this study can help golf industry in general. To make a greater improvements on golf industry with more job opportunity following ideas were presented. First, improving education on "hand on experiences on the field of golf industry" Better educating potential employees for golf industry for the right positions can enhance overall work environment. To do so, the society and the schools must come to agreement to provide adequate curriculum for people. Second, implementing "a golf club division program." The support from Ministry of Culture and Sports and Tourism Department, which are govern by Republic of Korea, are aggressively working to expend the golf business and also recruit elite personnel like former tour players to work on the field to better operate the whole system. Third, performing a thorough research on current golf related jobs and numbers and diversity on the field. Fourth, developing a specific and a differentiated golf job fields for better future for people and students who majored in golf industry. So that they cam feel secured and have a sense of dignity. Finally, strengthening the golf industry's competitiveness. The golf related companies have to step up to higher gear. With working in harmony between golf industry and government can assure of brighter future for our next generation.