• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.270-273
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• 2009

A comb-like copolymer consisting of a poly(vinylidene fluoride-co-chlorotrifluoro-ethylene) backbone and poly(hydroxy ethyl acrylate) side chains, i.e. P(VDF-co-CTFE)-g-PHEA, was synthesized through atom transfer radical polymerization (ATRP) using CTFE units as a macroinitiator. Successful synthesis and a microphase-separated structure of the copolymer were confirmed by proton nuclear magnetic resonance (1H-NMR), FT-IR spectroscopy, and transmission electron microscopy (TEM). This comb-like polymer was crosslinked with 4,5-imidazole dicarboxylic acid (IDA) via the esterification of the -OH groups of PHEA and the -COOH groups of IDA. Upon doping with phosphoric acid ($H_3PO_4$) to form imidazole-$H_3PO_4$ complexes, the proton conductivity of the membranes continuously increased with increasing $H_3PO_4$ content. A maximum proton conductivity of 0.015 S/cm was achieved at $120^{\circ}C$ under anhydrous conditions. In addition, these P(VDF-co-CTFE)-g-PHEA/IDA/$H_3PO_4$ membranes exhibited good mechanical properties (765 MPa of Young's modulus), and high thermal stability up to $250^{\circ}C$, as determined by a universal testing machine (UTM) and thermal gravimetric analysis (TGA), respectively.

• Journal of the Korean Vacuum Society
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• v.7 no.3
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• pp.237-241
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• 1998

The growth orientation and the surface roughness of AIN/Si(111) films grown by radio frequency (RF) reactive magnetron sputtering were investigated using in-situ x-ray scattering technique and atomic force microscopy (AFM). AIN films were initially grown with the <001> preferred growth orientation under most growth conditions. As the film gets thicker, however, the growth orientation changes significantly, especially at high substrate temperature and high RF powers. We attribute the observed behavior to the competition between the surface energy that prefers the <001> growth orientation and the strain energy that randomizes the growth orientation. In addition, we investigated the evolution of the surface morphology during the growth using the x-ray reflectivity measurement.

• IEMEK Journal of Embedded Systems and Applications
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• v.11 no.4
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• pp.243-249
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• 2016

Energy-harvesting nodes in wireless sensor networks(WSNs) can be exhausted due to a heavy workload even though they can harvest energy from their environment. On contrast, they can sometimes fully charged, thus waste the harvested energy due to the limited battery-capacity. In order to utilize the harvested energy efficiently, we introduce a selective data compression and transmission range control scheme for energy-harvesting nodes. In this scheme, if the residual energy of a node is expected to run over the battery capacity, the node spends the surplus energy to exploit the data compression or the transmission range expansion; these operations can reduce the burden of intermediate nodes at the expanse of its own energy. Otherwise, the node performs only basic operations such as sensing or transmitting so as to avoid its blackout time. Simulation result verifies that the proposed scheme gathers more data with fewer number of blackout nodes than other schemes by consuming energy efficiently.

• Environmental and Resource Economics Review
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• v.19 no.3
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• pp.633-658
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• 2010

In this paper, we estimate the Translog cost function in Korean manufacturing, using capital (K), labor (L), material (M), electricity (E), fuel (F) data over the period from 1970 to 2005. Especially, this paper investigates the impact of imposing concavity in the estimation of a Translog cost function. Although the value of log-likelihood is somewhat reduced in a concavity imposed function rather than a function which is not, a concavity imposed function satisfies regularity conditions (monotonicity, positivity, concavity) at all data points. We also calculate price elasticities using a concavity imposed Translog cost function. Electricity complements capital so electricity demand increases as capital demand increases. Meanwhile, electricity substitutes labor, fuel, and material. These results show that Korean manufacturing experienced a structural change of increase in electricity demand.

• Journal of IKEEE
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• v.22 no.4
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• pp.959-964
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• 2018

In this study, a study is conducted on a monitoring system that can control the environment of plants using sensors in conjunction with the LED light system and the plant growth control system. To verify the performance of the developed plant growth system, an experiment was conducted on the characteristics of energy efficiency, data transmission rate, and light volume control. The experiment resulted in a satisfactory result by controlling more than 80% energy efficiency, 1Mb/sec wireless communication speed, and 5 levels of optical control. The proposed system can be applied to LED plant facilities and will contribute to the automation of agriculture by organizing an automated system for production efficiency and labor cost reduction for future commercialization.

• Nuclear industry
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• v.38 no.3
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• pp.5-7
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• 2018

원전 관련 기관은 물론, 학계, 산업계, 노동계, 여성계, 언론계, 청년 학생 대표 등 각계각층 인사들이 자발적으로 참여하여 구성된 '원전수출 국민행동'(이하 '원국행')은 3월 20일 한국프레스센터 19층 기자회견장에서 '원전수출 국민행동 출범 기자회견'을 갖고 본격적인 원전 수출 국민 운동에 나섰다. 원국행은 기자회견에서 자타가 공인하는 세계 최고의 수준에 도달한 한국 원자력발전의 기술을 세계에 수출하는 것이야말로 경제적 위기를 극복할 가장 확실한 대안임을 강조하고, 우리 국민 모두가 정부와 힘을 합쳐 합심하여 원전 수출을 지원한다면, 연간 150조 원 규모의 에너지 수출에 원전이 중심적 역할을 할 수 있음을 호소했다. 원전수출 국민행동은 4월 21일 오후 2시 서울 광화문광장에서 범국민적 조직의 출발을 기념하는 '원전수출 국민통합대회'를 개최할 예정이다. 다음은 기자회견문 전문이다.

• IEMEK Journal of Embedded Systems and Applications
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• v.11 no.2
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• pp.79-86
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• 2016

In wireless sensor networks, increasing the sensing rate of each node to improve the data accuracy usually incurs a decrease of network lifetime. In this study, an energy-adaptive data compression scheme is proposed to efficiently control the sensing rate in an energy-harvesting wireless sensor network (WSN). In the proposed scheme, by utilizing the surplus energy effectively for the data compression, each node can increase the sensing rate without any rise of blackout time. Simulation result verifies that the proposed scheme gathers more amount of sensory data per unit time with lower number of blackout nodes than the other compression schemes for WSN.

• Korea Petroleum Association Journal
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• no.7 s.185
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• pp.77-79
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• 1996

95년중 우리나라는 1인당 국민소득이 처음으로 1만달러를 넘어 섰으며, 경제규모 (경상GNP)는 4,517억달러로 세계 11위, 교역규모는 2,603억달러로 세계13위(94년기준) 국가로 부상하였음. 경제구조면에서도 농림어업의 비중이 낮아지고 광공업 및 서비스업의 비중이 높아지는 등 산업구조가 고도화되었으며, 최종 소비지출의 비중이 낮아진 반면 설비 및 건설투자의 비중이 높아졌음. 또한 엥겔계수가 낮아지고 노동소득분배율이 높아지는 등 경제구조가 전반적으로 선진국형에 근접해가고 있는 것으로 나타났음. 이와 같은 경제발전에 따라 제조업 근로자의 주당 평균 근로시간, 인구 1만명당 의사수, 주택 보급률, 고등교육기관 학생수 및 연구개발투자액의 대GNP 비중 등 주요사회지표가 크게 호전된 것으로 나타났음. 특히 이중에서도 고등교육기관 학생수 및 연구개발투자액의 대GNP비중등은 우리나라의 높은 교육열등을 반영하여 주요국의 1만달러시기 수준보다 높은 것으로 나타났음.

• 한국연소학회:학술대회논문집
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• 2013.06a
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• pp.121-122
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• 2013

In recent years, the usage of fossil fuels has caused problems of climate change and global warming. Because the combustion of fossil fuels is related to the production of greenhouse gases ($CO_2$, $CH_4$, etc.), new technology in the field of combustion is needed in order to handle the crisis of climate change and the global warming. As one of the efforts to reduce the emission of greenhouse gases, the concept of regenerative oxy-fuel combustion for energy efficiency and carbon capture was suggested, In the current study, the development of an industrial regenerative oxy-fuel combustion furnace was introduced, which has been being performed at Korea Institute of Energy Research (KIER).

• Korea journal of population studies
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• v.34 no.2
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• pp.45-64
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• 2011

This study examines changes and educational differences in parental time spent in childcare. Based on time diary data 1999-2009, it finds as follows. First, compared to 1999, parental time spent in childcare has increased in 2009. Unlike the tendency of convergence of time spent in childcare by sex in US, differences by sex have increased in Korea. Second, those who are highly educated tend to spend more time with children than their counterparts. For preschool aged children, parental time spent in physical care and playing has significantly increased by educational level. For school aged children, those who are highly educated are more likely than those who have lower level of education to help with children's study. Third, compared to 1999, time for leisure and economic activity has decreased in 2009 whereas time for commute, sleep, and care for others has increased.