• KSBB Journal
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• v.14 no.3
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• pp.284-290
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• 1999

Glucose fed-batch culture was studied to improve cellulose productivity by Acetobacter xylinum BRC5. When initial glucose concentrations in batch cultures were less than 20 g/L, yield coefficients of cellulose (Yp/s) remained a constant value of 0.21 g cellulose/g glucose. But a low yield coefficient, Yp/s=0.13 was obtained from an initial glucose concentration of 40 g/L. Since initial high glucose concentrations in batch culture resulted in low yields of cellulose, constant fed-batch cultures were carried out. The optimal feed rate for fed-batch culture was 2.22 g glucose/L.h. In constant fed-batch culture without DO control, 10 g/L of cellulose was obtained from 40 g/L of glucose with this feed rate, which was approximately two fold higher than that of the batch culture with the same initial glucose concentration. In DO stat plus fed-batch culture, the highest cellulose productivity could be obtained when dissolved oxygen level was controlled at 10% of air saturation, and cellulose productivity increased about 1.5 times compared with that of the culture without DO control.

• Korean Journal of Medicinal Crop Science
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• v.3 no.1
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• pp.30-34
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• 1995

Theses studies were conducted to clarify the germinating characteristics of seed treated with different temperature, light, and ($Gibberellin(GA_3)$) to produce the homogeneous seedlings Angelicogigas NAKAI. The results obtained are summarized as follows: Rate and speed of germinating at $25^{\circ}C$ were higher than $15^{\circ}C$and $20^{\circ}C$ by 87.3% and 68.9% and also the required day for germination at 25°C was shortest by 14.1 days. Germination rate at the light condition was 90.7% and that at the dark was 65.7%. Germinating ability of seed stored at $4^{\circ}C$and $-10^{\circ}C$ for 165 days as dried states was 92.0% and 91.3%, while that at room temperature was 50.3%, but the longer storage of seed than 165 days decreased the ability. Gibberellin treatment by 10ppm to seed stored at $4^{\circ}C$ and by 6ppm to seed stored at $-10^{\circ}C$ increased the germination rate more by 20.9% and 31.7% than nontreated seed.

• The Journal of the Korea Contents Association
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• v.22 no.5
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• pp.576-584
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• 2022

As an important branch of cognitive psychology, "constructivism" is called a "revolution" in contemporary educational psychology, which has a profound influence on the field of pedagogy and psychology. Based on "WOS" database, this study selects "WOS Core database" and "KCI database", uses CiteSpace visualization software as analysis tool, and makes knowledge map analysis on the research literature of "constructivism" in the field of education in recent 35 years. Analysis directions include annual analysis, network connection analysis by country(region) branch, author, institution or University, and keyword analysis. The purpose of the analysis is to grasp the subject areas, research hotspots and future trends of the research on constructivism, and to provide theoretical reference for the research on constructivism. There are three conclusions from the study. 1. Studies on the subject of constructivism have continued from the 1980s to the present. It is now in a period of steady development. 2. Countries concerned with the subject of constructivism mainly include the United States, Canada, Britain, Australia and the Netherlands. The main research institutions and authors are mainly located in these countries. 3. Currently, the keywords constructivism research focus on the clusters of "instructional strategies", and the development of science and technology is affecting individual learning. In the future, instructional strategies will become the focus of structural constructivism research. With the development of instructional technology, it is necessary to conduct research related to the development of new teaching models.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3D
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• pp.453-459
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• 2006

This paper presents an experimental evaluation of wandering effect on asphalt concrete pavement responses. A laser-based wandering system has been developed and its performance is verified under various field conditions. The portable wandering system composed of two laser sensors with Position Sensitive Devices can allow one to measure the distance between laser sensors and tire edges of moving vehicle. Therefore, lateral position of each wheel on the pavement can be determined in a real time manner. Pavement responses due to different loading paths are investigated using a roll over test which is carried out on one of asphalt surfaced pavements in the Korea Highway Corporation test road. The pavement section (A5) consists of 5 cm thick surface course; 7 cm intermediate course; and 18 mm base course, and is heavily instrumented with strain gauges, vertical soil pressure cells and thermo-couples. From the center of wheel paths, seven equally-spaced lateral loading paths are carefully selected over an 140 cm wandering zone. Test results show that lateral horizontal strains in both surface and intermediate courses are mostly compressive right under the loading path and tensile strains start to develop as the loading offset becomes 40 cm from the wheel path. The development of the vertical stresses in the top layers of subbase and anti-frost is found to be minimal once the loading offset becomes 50 cm.

• Korean Journal of Social Welfare
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• v.58 no.1
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• pp.175-207
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• 2006

Beveridge report has been supported by domestic and overseas since the second world war and has considerately effected on welfare policy of many countries including UK. But criticism regarding his social security's principles assumptions continuously has been proposed since the 1990s. Certainly, no one might object to the truth that there might be no possibility to come true Beveridge's principles and assumptions. However according to this studies, some of these criticisms were based on wrong understanding, interpretation or recent situation and policy which was executed differently from Beveridge's meaning. It's shown that Beveridge has been more misestimated than what he has to be suffered. Therefore from now on, it is constructive to endeavor to set up the better principles and assumption of social security which can adhere to social solidarity and universalism as well as preserve and improve welfare state' ideology and value considering transformed circumstances rather than criticize Beveridge's principles and assumptions that was suitable for that time.

• The Journal of the Korea Contents Association
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• v.9 no.4
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• pp.154-161
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• 2009

Thanks to the circumstance of digital convergence, most of the world TV and radio stations are gearing up for digitalisation of broadcasting. In this flux, digital switchover in South Korea should be completed by 2012 when transmission of analogue broadcasting signal will be ceased. According to the report, it shows only over 30% take up roughly so far, but there is no official survey from relevant organisation. It is very comparable with British digital switchover which is same year as S. Korea and has been reported 88% take up as of 2008 Q2. Yet the digital switchover in S. Korea inferred from this current is not a rosy future and even seems to be perilous. The purpose of this paper is to predict the media future of S. Korea at the view point of futurology and draw out the possibilities which enable to affect viewing behavior. In order to analyse it applies the futures wheel which is one of useful tools for future work. Consequently it suggests a number of scenarios how to cope with the impending situation in S. Korea.

• Composites Research
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• v.33 no.5
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• pp.268-274
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• 2020

This paper analyzed the degradation behaviors of silica nano epoxy composite based on the isoconversional method. The size of the silica nano particle was about 12 nm and the particles were mixed by three different weight ratios to make the degradation test samples. The thermogravimetric analyses were performed under six different temperature increase rates to measure the weight changes. Four different methods, Friedman, Flynn-Wall-Ozawa, Kissinger and DAEM (Distributed Activation Energy Method), were employed to calculate the activation energies depending on the conversion ratios, and their calculation results were compared. The results represented that the activation energy was increased when the silica nano particles were mixed up to 10%, indicating the definite contribution of the particles to the degradation behavior enhancements. However, the enhancement was not proportional to the particle mixture ratio by demonstrating the similar activation energies between 10% and 18% samples. The calculation results by the different methods were also compared and discussed.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1058-1062
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• 2008

지구 온난화에 의한 대기 순환의 변화와 이에 따른 수증기 수송 및 강수량의 변화는 전지구 및 지역적인 수문환경의 변화를 초래하므로 장기적인 차원의 수자원 계획 수립에는 반드시 기후 변화에 따른 영향이 제대로 반영되어야 한다. 그러나 개별 모델이 사용하는 역학과정과 물리과정의 모수화 및 분해능이 다르고 이에 따른 모의 결과도 다르게 나타나는 등의 상당한 불확실성이 내재되어 있다. 따라서 본 연구에서는 기후변화에 관한 정부간 패널인 IPCC(Intergovernmental Panel on Climate Change)에 참여한 대기해양결합 대순환모델(AOGCMs)이 온실가스 배출 시나리오를 바탕으로 생산한 기온과 강수의 불확실성을 동아시아에 대해 평가하고 이를 바탕으로 미래 기후를 전망하였다. 국립기상연구소 ECHO-G/S 모델과 IPCC 23개 모델의 배출 시나리오(Special Report on Emissions Scenarios, SRES) 자료는 20세기(1900-1999년)와 21세기(2000-2099년)의 200년 동안이고, 관측자료는 영국 CRU(Climate Research Unit) 월평균 2m 기온의 30년(1961-1990년) 평균값과 CMAP 월 평균 강수량의 21년간(1979-1990년) 평균값을 이용하였다. 동아시아지역 기온과 강수의 불확실성을 평가하기 위해서 모델과 관측간 편이, 평균제곱근오차(RMSE) 등의 통계적인 방법을 사용하였다. 동아시아 지역의 연평균 기온은 대체로 모델의 기온이 관측보다 적게 모의되는 음의 편이를 나타내고, 강수는 모델이 관측보다 더 크게 모의 되는 양의 편이를 나타냈다. 계절적으로는 여름철 강수와 봄철 기온의 편이가 크게 나타났다. 연평균 및 겨울철 강수와 기온의 RMSE는 비례하는데 이는 기온 모의성능이 좋은 모델이 강수 모의성능도 좋게 나타나는 것을 의미한다.

• Nuclear industry
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• v.35 no.9
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• pp.46-52
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• 2015

1975년 우라늄협회로 출발한 세계원자력협회(WNA)는 원자력을 평화적으로 이용하는 것을 적극 지원하고, 원자력 발전과 핵연료주기 전반에 걸친 원자력 산업 발전을 위하고자 설립한 세계적 민간 기구로, 우라늄 채광부터 변환, 농축, 핵연료 제조, 원자력발전 운영, 기자재(설비) 제작 및 사용후핵연료 처분에 이르기까지 원자력발전의 전 주기 산업을 촉진하고 관련 정보를 지원하고 있다. 2001년 지금의 명칭으로 변경한 WNA는 전 세계 원자력산업체와 원자력 관련 기관, 대학 등 175개 회원사를 두고 상호 협력과 전문 인력 교육 기반 강화, 국제화에 적극 나서고 있으며, 원자력산업 정보 제공과 교환을 위해 관련 보고서와 자료도 수시로 발행하고 있다. 2013년부터 WNA를 이끌고 있는 아그네타 라이징 사무총장은 지난 11월 영국 런던 소재 WNA를 방문한 <원자력신문>과의 인터뷰를 통해, 원전과 주변지역 주민의 갑상선암 발병에 대한 인과 관계에 대하여 "갑상선암 발병이 원전과 연관성 있다는 주장은 과학적 근거가 없다"고 단호히 말하고, "한국과 유사한 사례가 해외 원자력계(과학계)와 의학계에 보고된 적이 있냐"는 질문에 "해외에서 정상 운영되고 있는 원전 시설은 국제방사선방호위원회(ICRP)의 엄격한 기준(ICRP-60)이 적용하고 있으며, 방사선 방호와 관련된 연구보고서(논문)를 꾸준히 내고 있지만 원전 주변 주민에 대한 여러 역학 조사에서도 갑상선암이 증가했다는 사례는 보고된 바 없다"고 말했다. 또한 "실제로 일본 원폭 생존자 연구와 체르노빌 원전 주변 주민 연구에 의하면 20세 이상의 성인에서 방사선 노출에 의해 갑상선암이 증가한다는 증거는 없었다."면서 "체르노빌 사고와 후쿠시마 원전 사고 이후 방사선 누출로 인해 방사선이 갑상선암의 발생률을 증가시키는 것으로 알려졌지만 실제로 원전에서 발생하는 방사능은 갑상선암을 유발시킬 수 있는 양에 비해 아주 적다. 그럼에도 원전 시설에서 나오는 방사능 수치에 대해 제대로 밝히는 기관이 없기 때문에 원전 주변에 살아도 영향을 받는 것으로 오해할 수 있다."고 덧붙였다. 아그네타 라이징 사무총장은 스웨덴 출신의 방사선 방호 전문가로, 스웨덴 국영기업 Vattenfall AB 그룹에서 원자력 에너지 환경 분야 최고 전문가로 활동했으며, 스웨덴원자력학회, 유럽원자력학회, 세계여성원자력전문인회(WiN-Global) 회장 등을 역임했다. 인터뷰 전문을 게재한다.

• The korean journal of orthodontics
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• v.23 no.3 s.42
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• pp.415-425
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• 1993

Fluoride is one of the most potent stimulators of bone formation in vivo. But its direct effects on osteoblast is not yet clear This study was to investigate the effects of Sodium fluoride on alkaline phosphatase(ALP) activity, cAMP formation responsive to parathormone(PTH) and type I $\alpha$ 2 collagen ribonucleic acid (mRNA) level in Murin osteoblast-like (MC3T3-E1) cells. The cells were cultured in $\alpha-Minimal$ essential medium $(\alpha-MEM)$ supplemente with $10\%$ fetal bovine serum (FBS) and then changed to $0.1\%$ FBS with various concentration of Sodium fluoride. The ALP activity was assayed by the method of Lowry with disodium phenyl phosphated as substrate. cAMP formation was measured by Radioimmuno Assay(RIA). Type I $\alpha$ 2 collagen ribonucleic acid(mRNA) expression was studied by Nothern blot analysis. The results were as follows: 1. cAMP level was increased by PTH in MC3T3-E1 cells. 2. Sodium fluoride showed the tendency of inhibitory effects on cAMP responsiveness to PTH in MC3T3-E1 cells. 3. Sodium fluoride increased ALP activity at cocentration of $2{\mu}M,\;4{\mu}M,\;and\;10{\mu}M$ significantly different from control at the 0.001 level. ALP activity revealed maximum value at $10{\mu}M$ in this study. 4. Nothern blot analysis of Sodium fluoride treated cells, using Type I $\alpha$ 2 collagen prove, revealed significant increase at $10{\mu}M$ in MC3T3-E1 cells.