• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.273-273
• /
• 2010

고열부하 환경에 노출되는 핵융합로의 플라즈마 대향부품은 주로 낮은 원자번호 물질-열전도가 좋은 물질-구조체의 순으로 다층 구조를 이루고 있으며, 이들 간의 우수한 접합성은 부품의 성능을 좌우하는 핵심 요소이다. 이러한 플라즈마 대향부품의 건전성을 평가하기 위해서는 고열속의 열부하를 반복적으로 인가하는 시험이 요구되며, 이를 위해 본 연구원에서는 KoHLT-1, 2의 시험시설을 운용하고 있다. 본 시설에서는 열부하원으로서 그라파이터 히터를 사용하며, 히터는 두 개의 시험 대상부품 사이에 설치되고, 히터에 고전류를 인가하여 복사열에 의해 시험 부품에 열부하를 가하게 된다. 고열부하 환경에서 열피로 시험을 위해 히터에 인가되는 전류를 시간에 따라 일정한 패턴으로 반복적으로 ON-OFF 하게 된다. 본 논문에서는 이러한 고열부하시험을 수행함에 있어 고려해야 할 여러 가지 요소에 대해 논의하였다. 우선 인가하는 열유속(heat flux) 값은 일차적으로 시험시설의 최대 출력에 의해 좌우되며, 시험대상물의 운전조건 및 열부하 반복횟수에 의해 결정된다. 열부하 반복횟수는 주어진 열유속 값에 대해 total strain이 파단에 이르는 수준에 의해 결정된다. 열부하를 인가하는 시간은 히터에 전류를 인가했을 때 요구되는 온도로 상승하는 데 걸리는 시간과 시험대상물의 온도가 더 이상 증가하지 않는데 걸리는 시간에 의해 좌우된다. 냉각시간은 길수록 시험대상물의 온도가 냉각수의 온도에 접근하게 되나 너무 길어지면 시험시간이 급격히 증가하게 되므로, 온도 감소 곡선을 검토하여 적절한 시간을 정하게 된다. 열유속 측정은 냉각수의 온도 상승값과 유량으로부터 계산하게 되며, 정확한 측정을 위해서는 열부하를 인가하는 시간이 충분히 길어야 한다. 또한 시험대상 부품에서 열부하가 인가되는 면적을 정확히 정의해야 하며, 냉각관로에 열부하가 인가되어서는 않된다. 또한 시험대상부품을 지지하는 지지구조체를 통한 열손실을 최소화해야 정확한 열유속을 측정할 수 있다. 시험대상부품을 설치할 때 히터와의 간격 또한 결정해야 할 중요한 요소이며, 간격이 좁을수록 최대 열유속 값을 증가시킬 수 있으나, 너무 가까운 경우 히터의 열변형에 의한 접촉 및 아크 방전의 가능성이 있으며, 이 경우 히터와 시험대상부품의 손상을 가져오게 된다. 시험대상물이 국제열핵융합로(ITER)의 일차벽과 같이 베릴륨이 포함되어 있는 경우 방전에 의한 손상은 인체에 유해한 오염의 원인이 될 수 있다. 또한 순간적인 방전은 고가의 고전류전원의 고장을 유발할 수도 있다. 열부하 시험 중 시험대상물의 온도를 정확히 측정하는 것은 필수적이며, 온도 변화 곡선으로부터 시험대상물의 건전성 여부를 판단할 수 있다. 이를 위해 변화를 가장 잘 탐지 할 수 있는 위치에 온도 센서를 설치하는 것이 관건이며, 이는 사전 분석을 통해 알 수 있다.

• Applied Chemistry for Engineering
• /
• v.25 no.1
• /
• pp.1-13
• /
• 2014

Lithium ion batteries (LIBs) are the state-of-the-art technology among electrochemical energy storage and conversion cells, and are still considered the most attractive class of battery in the future due to their high specific energy density, high efficiency, and long cycle life. Rapid development of power-hungry commercial electronics and large-scale energy storage applications (e.g. off-peak electrical energy storage), however, requires novel anode materials that have higher energy densities to replace conventional graphite electrodes. Germanium (Ge) and silicon (Si) are thought to be ideal prospect candidates for next generation LIB anodes due to their extremely high theoretical energy capacities. For instance, Ge offers relatively lower volume change during cycling, better Li insertion/extraction kinetics, and higher electronic conductivity than Si. In this focused review, we briefly describe the basic concepts of LIBs and then look at the characteristics of ideal anode materials that can provide greatly improved electrochemical performance, including high capacity, better cycling behavior, and rate capability. We then discuss how, in the future, Ge anode materials (Ge and Ge oxides, Ge-carbon composites, and other Ge-based composites) could increase the capacity of today's Li batteries. In recent years, considerable efforts have been made to fulfill the requirements of excellent anode materials, especially using these materials at the nanoscale. This article shall serve as a handy reference, as well as starting point, for future research related to high capacity LIB anodes, especially based on semiconductor Ge and Si.

• Journal of Science and Technology Studies
• /
• v.3 no.2 s.6
• /
• pp.29-60
• /
• 2003

Inter-Korean Cooperation in Science and Technology will contribute to building the trust between S.K and N.K as a leading factor and cut down the cost of unification by diminishing the technology lag and the gap of economic level. This study has shown that we can increase the productivity of unified Korea Innovation system if we systematically analyse the present condition of the Inter-Korean Cooperation and promote Inter-Korean Cooperation. In this study, the author analyses the present condition of the Inter-Korean Cooperation with integrated framework of three aspects to clear up the policy of Inter-Korean Cooperation. First, in the national aspect, we make use of the notion of international cooperation and multilateral mechanism of an international organization. Thereafter, we make out the alternatives in the aspects of international relationship and legal and institutional view Second, in the unification aspect, we consider the Inter-Korean Cooperation by the notion of national innovation system. Thereafter, we make out the alternative in the aspect of a phase-dependent approach. Finally, in technology aspect, we consider the Inter-Korean Cooperation by the notion of technology gap, the framework of technology transfer, and technology dependency theory. As a conclusion, through this study, the author have tried to integrate the various theoretical backgrounds. As a result, the author could analyse the present condition of ter-Korean Cooperation in Science and Technology and team a good lesson from it; Therefore, we can use it as a means of evaluation on a cooperation program and prediction for the future status of cooperation.

• Korean Journal of Social Welfare
• /
• v.51
• /
• pp.5-28
• /
• 2002

The purpose of this paper is to examine the issues and the characteristics of the recent social security pension debate in the United States. For the purpose the transforming process from the funded system to the pay-as-you-go system in the 1930s, three alternatives of social security reform proposed by the Social Security Administration in 1996, and the other various alternatives proposed by the politicians, the business leaders and the scholars were analysed. While the alternatives were compared, the critical issues could be identified. The core issues were as follows. First, the individual accounts should be newly made or not? Second, who is the main administrator, government or private investment companies? Third, what is important, the inter-generational and the vertical income redistribution effect or the individual equity in social security pension system? Besides, the different positions of the social forces were also examined. The supporters of privatizing the social security pension, supporters of IA and PSA, prefer the value of equity, the effect of promoting savings, the private management of the social security funds, and the investment of the funds to the private capital markets. The supporters of pay-as-you-go system, supporters of MB, prefer the inter-generational and the vertical income redistribution effect of social security pension, and were convinced that fundamental changes of the systems are not necessary, and the insolvency problem could be overcome through a few reform, for example, increasing the rate and decreasing the benefits.

• 재활복지
• /
• v.21 no.1
• /
• pp.253-277
• /
• 2017

The purpose of this study was to develop the Constraints in Physical Activity Scale for people with physical Disabilities(CPASD) which measures the constraints in physical activity of people with physical disabilities. For this study, the 5 step analytic framework of unified validity developed by Messick (1995), the framework for conducting a strong program of construct validation by Benson (1998) method were applied. Furthermore, the validity of CPASD was systematically presented by applying common factor model and measurement model to 264 persons with physical disabilities. The conclusion based on the results and discussions of this study is as follows. First, CPASD presented evidence of job validity. Four factors (17 items) were developed, consisting of leader constraints, economic constraints, prejudice, and exercise environment constraints through the analysis of the factor structure and the fit of factor coefficients. Second, the factor structure of the developed CPASD (leader constraint, economic constraint, prejudice, exercise environment constraint) was statistically distinguished and stably reflected the existing exercise participation constraints theory. Third, the developed CPASD presented evidence of the validity of the criteria. Leader constraints and prejudice were negatively correlated with positive motor emotions, leader constraints, prejudice, and exercise environment constraints were positively correlated with negative motor emotions. Therefore, in future research, it is necessary to reevaluate the current system and actual condition related to leader constraints, economic constraints, prejudices, and exercise environment constraints derived as factors of CPASD. To do this, it is necessary to judge the degree of reality based on the causal relationship verification and IRT theory using CPASD.

• Journal of Korean Historical Folklife
• /
• no.45
• /
• pp.7-50
• /
• 2014

This study focuses on the funeral rites for Queen Wongyeong during the early Joseon period as part of a review of the changes in the state funeral system and ceremonial procedures. Conducted by the king in his role as chief mourner, the state funeral for King Taejong's wife Queen Wongyeong that emerged during the 2nd year of King Sejong marked the first example recorded in the sillok (Annals of the Joseon Dynasty) of the three year-mourning rite being applied. In terms of the clothing for the state funeral, the significance of Jolgok (a rite conducted on the 100th day following the day of death) was emphasized, while the existing yeokwolje (period of wearing mourning clothes, one month was equated with one day) was abandoned. The existing temporary office system for state funerals was reorganized into a three-office system consisting of the Binjeon dogam (Office for Chapel of Rest), Gukjang dogam (Office for Funeral Rites), and Salleung dogam (Office for the Establishment of Royal Tombs). Buddhism-related rites greatly decreased and were increasingly regulated. The ceremonial procedures were also modified in accordance with the rites directly conducted by the king during the three-year mourning period. The basic pattern of the ceremonial procedure consisted of kneeling / wailing - salute - kneeling/ wailing, and, based on the wuje (rites to console the deceased), was divided into 'make offerings to the deceased' (奠, jeon) and 'hold a memorial service for the deceased' (祭, je). This reflected the differing perceptions of jeon (奠) and je (祭) following the establishment of auspicious rites (gillye) during the reign of King Taejong. In short, the state funeral for Queen Wongyeong provides materials with which to analyze the establishment of the funeral rites and ceremonial procedures designed based on the actual three-year mourning period observed by the king, study the ritual ceremonies conducted during the ancient period, as well as foster an understanding of ancient systems.

• Korean Journal of Remote Sensing
• /
• v.15 no.3
• /
• pp.253-266
• /
• 1999

ADEOS(Advanced Earth Observing Satellite)/IMG(Interferometric Monitor for Greenhouse Gases) measurements - temperature, water vapor($H_2O$), ozone($O_3$) have been compared with the radio sonde and ozone sonde observations at Osan and Pohang stations for the 4 cases on 10 Jan.(a), 28 Jan.(b), 2 Apr.(c), and 19 Jun.(d) 1997 to detect the error ranges of the IMG data. It showed that the IMG data of the cases (b), (d) when the ADEOS passed over the central part of Korea were quite stable with the good agreement with the sonde observations, however, that of (a),(c) when the ADEOS passed over south- east coastal area were unstable with the larger differences from the sonde-observations. The RMSE and bias analyses of temperature for the stable cases (b),(d) showed that the differences between the IMG data and the sonde observations were about 1~4 K at the 700~300 hPa level and about 4~5 K or more at the higher level, and the IMG measurements tended to be larger than the sonde observations at the higher level above 200 hPa, while no typical bias was seen at the lower level. The RMSE and bias analysis for the version of level 2 5_6_4_4 of ozone showed that the RMSE of ozone were quite small, in general, except at the higher level above 50~60 hPa in the all 4 cases, however the bias was generally big with the positive value in the troposphere and the negative in the stratosphere. An example of vertical profile of trace gases such as $CO_2, N_2O, CH_4, HNO_3$, CO measured by IMG was also presented and it showed that the IMG data had large differences between the 5 different observation points.

• Journal of the Korean Society of Child Welfare
• /
• no.36
• /
• pp.101-132
• /
• 2011

Using data collected from Korean mothers (N＝429) with preschool children (aged 3 to 5 years) in 12 day care centers in Seoul, this study aims to empirically demonstrate the different pathways acute and chronic stress affect parenting efficacy of mothers according to the income group to which they belong. Analytic results show mothers in the low-income group show higher levels of depressive symptoms than mothers in the middle-income group, and the former also show more frequent and higher levels of acute and chronic stress than the latter. The mediation model results show that acute stress and chronic stress did not directly affect parenting efficacy, but rather indirectly affect parenting efficacy through maternal depressive symptoms. Acute stress and chronic stress are both significant factors affecting depressive symptoms with chronic stress exerting greater influence. When the total effect was analyzed, chronic stress has a greater effect on parenting efficacy than acute stress. The effect of chronic stress on maternal depressive symptoms is greater on low-income mothers than middle-income mothers, while the effect of acute stress on maternal depressive symptoms and the effect of those symptoms on parenting efficacy are greater on middle class families than low-income families. In order to maximize effective parenting in high-risk situations, the psychological welfare of mothers needs to be protected from the environmental difficulties they face. Based on the results, policies to support women and parents at the national and social levels are discussed.

• Korean Journal of Social Welfare Studies
• /
• v.49 no.2
• /
• pp.181-209
• /
• 2018

This study aims to examine the relationship between physical environment and depression symptoms of middle-aged and older adults in metro city. To verify correlates of community environment and depression, mediating effect model structured by social capital and sense of coherence(SOC) were used. For the purpose, a survey was conducted aged 48 - 70 from the local community centers and senior welfare centers in Seoul, and the total collected cases were 331. After data cleaning, total 309 cases were used. The structured equation modeling applied to analyse the direct and indirect effects. The findings were followed : First, the community environment did not directly affect level of depression. Second, in the indirect effect analysis, social capital was not statistically significant, thus indirect effect was confirmed only through the SOC. To be specific, the higher the satisfaction of the physical environment increased SOC, and decreased the level of depression. The results of this study shed lights on practical interventions to promote mental health of the middle-aged and older adults those who are exposed to poor community environment.

• Korean Journal of Comparative Education
• /
• v.26 no.4
• /
• pp.55-80
• /
• 2016

Kerala, a southern-west state of India, has been vigorously studied due to its unique development status. Indeed, Kerala shows such a high level of social development as Human Development Index indicates, yet it is suffering from the low level of economic. As a result, scholars have examined a broad range of rationales to understand the 'Kerala Development Model' as discussing historical contexts, social welfare policies, land reforms by Communist Party of India, and so on. Among them, scholars agree that education is one of the most critical factors that led to social development of Kerala. Despite the consensus, there has been lack of research that deeply look into how education has been delivered, what impacts it has on people, and why it contributes to social development in Kerala. This research, thus, would discuss the meanings, values and impacts of education with the capability approach that is originally termed by Amartya Sen. The approach criticize the dominant paradigm of 'development' that is materialistic oriented, instead it emphasizes expanding a range of capabilities of people to reach 'development' that people can act upon what they value and cherish. Based on Sen's perspective, we believe that dimensions of education can be re-defined and expanded in a relation to development.