• 한국가정과교육학회지
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• 제33권4호
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• pp.31-48
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• 2021

본 연구는 고령화연구패널조사(KLoSA)의 1-6차 연도 자료를 분석하여 노년기의 우울, 만성질환, 인지기능의 다중적 측면에서의 건강 변화 유형을 파악하고 이와 관련이 있는 요인들을 분석하고자 하였다. 연구의 대상은 1차 연도 조사 시점에서 65세 이상이고 결측률이 없는 총 2,059명이다. 잠재성장모형을 통해 세 가지 건강 측면이 시간에 따라 어떠한 변화궤적을 보이는지 살펴보았으며, 성장혼합모형을 활용해 세 건강 요인에서 서로 다른 변화 궤적을 보이는 집단들을 유형화하였다. 또한 일원분산분석 및 Scheffé 사후검증, 교차분석을 통해 건강 변화유형 집단에 따라 인구사회학적 특성, 건강행동, 삶의 만족도에서 차이가 나타나는지를 살펴보았다. 본 연구의 주요 결과는 다음과 같다. 첫째, 잠재성장모형 분석 결과 우울과 만성질환의 수는 연령에 따라 점차 증가하고 인지기능은 점차 감소했다. 둘째, 성장혼합모형을 분석한 결과 노인의 건강 변화는 일반적 노화, 질환 증가, 만성적 문제의 세 집단으로 유형화되었다. 셋째, 노인의 인구사회학적 특성, 건강행동, 삶의 만족도는 세 집단에 따라 유의한 차이가 나타났다. 특히 만성적 문제 집단의 경우 교육 및 소득수준이 낮고, 전반적으로 낮은 삶의 만족도를 나타냈다. 본 연구는 노년기 건강증진 교육 프로그램에 있어 노인들이 경험하는 건강의 다중적 측면을 고려하는 것이 중요함을 보여주며, 노년기 건강증진 교육 프로그램을 위한 제언을 제공한다. 또한 전생애적 건강관리를 위한 건강정보문해력 증진에 있어서 가정과 교과과정이 갖는 중요성에 대해 논의하고자 한다.

• 자원환경지질
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• 제43권5호
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• pp.523-528
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• 2010

미국발 금융위기 여파로 세계경제가 침체되변서 LME의 base metal 가격이 2008년 4/4, 분기 급락하였으나, 2009년 1-7월 거시경제 회복신호와 함께 base metal 가격이 다시 상승세를 보였다. Base meta1 상승 배경에는 미국 기업들의 개선된 실적 발표로 산업생산 및 제조업지수가 개선된 것 미달러화 약세로 인한 원자재 가격 상승, 그리고 무엇보다도 세계 금융 위기 속에도 경제성장을 위한 중국의 원자재 수요 증가가 주요 원인으로 꼽힌다. 이에 본 논문에서는 base metal 가격상승에 주요 base metal소비국의 수요가 영향을 주었는지를 중국 및 주요국 경제성장률을 가지고 회귀분석 하였다. 분석결과 중국의 경제 성장만이 LME시장의 base metal 가격상승에 영향을 주는 것으로 나타났다. 하지만 이런 결과에도 불구하고, 그동안 중국 상품의 주요 소비시장이었던 미국, 유럽 동 선진국들 경제의 본격적인 회복 없이 중국경제만으로 base metal 가격 상승랠리가 지속될지 여부를 보고자 한다.

• Composites Research
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• 제34권5호
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• pp.323-329
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• 2021

본 논문에서는 불균일한 접착 상태를 가지는 복합재 접착 체결 시편에 대하여 모드 I 하중에서의 파괴 특성을 분석하였다. 이를 위하여 Double Cantilever Beam(DCB) 시험을 수행하였으며 모드 I 파괴 인성을 도출하였다. 불균일한 접착 상태를 갖는 시편의 경우 안정한 균열 성장 구간과 불안정한 균열 성장 구간이 나타남을 확인하였다. DCB 시험에서 구한 하중-변위 선도와 시편의 파손 단면을 통해 각 구간의 파괴 특성을 관찰하였다. 시험에서 측정된 균열 길이를 기준으로 세분화된 구간과 각 구간의 모드 I 파괴 인성을 이용하여 유한요소해석을 수행하였다. DCB 시험 결과와 유한요소해석 결과를 통해 불균일한 접착 상태를 가지는 시편의 파괴 거동을 모사할 수 있음을 확인하였다.

• 한국결정성장학회지
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• 제15권6호
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• pp.239-243
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• 2005

The effect of pH and particle size on the dispersion stability of ultra-fine $BaTiO_3$ suspensions in aqueous medium have been investigated by means of zeta potential, sediment experiments, and powder properties (particle analysis, specific surface area) etc. Zeta potential as a function of pH for two particles of different size increases from -75 to +10 mV with decreasing pH from 8.5 to 1.4. The curve of zeta potential for small particle (150 nm) has slow slope than that of large particle (900nm), giving IEP (isoelectric point) value of pH=1.6 for small particle and pH=1.9 for large particle respectively, which means that it is more difficult to control zeta potential with pH fur small particle than large particle. The dispersion stability of $BaTiO_3$ particles in aqueous medium was found to be strongly related with the agglomeration of colloidal suspensions with time through the sedimentation behaviors of colloidal particles with time and pH value.

• Structural Engineering and Mechanics
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• 제32권3호
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• pp.459-475
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• 2009

This paper presents analytical methodologies for remaining life prediction of plain concrete structural components considering tension softening and size effects. Non-linear fracture mechanics principles (NLFM) have been used for crack growth analysis and remaining life prediction. Various tension softening models such as linear, bi-linear, tri-linear, exponential and power curve have been presented with appropriate expressions. Size effect has been accounted for by modifying the Paris law, leading to a size adjusted Paris law, which gives crack length increment per cycle as a power function of the amplitude of a size adjusted stress intensity factor (SIF). Details of tension softening effects and size effect in the computation of SIF and remaining life prediction have been presented. Numerical studies have been conducted on three point bending concrete beams under constant amplitude loading. The predicted remaining life values with the combination of tension softening & size effects are in close agreement with the corresponding experimental values available in the literature for all the tension softening models.

• The Journal of Asian Finance, Economics and Business
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• 제4권4호
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• pp.61-66
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• 2017

Environmental awareness and its relation to the development of economy has garnered increased attention in recent years. Researchers, over the years, have argued that sustainable development warrants for minimizing environmental degradation since one depends on the other. This study analyzes the relationship between environmental degradation (carbon emission taken as proxy for degradation), economic growth, total energy consumption and industrial production index growth in Bangladesh from year 1998 to 2013. This study uses Vector Autoregression (VAR) Model and variance decomposition of VAR to analyze the effect of these variables on carbon emission and vice-versa. The findings of VAR model suggest that industrial production and GDP per capita has significant relationship with carbon emission. Further analysis through variance decomposition shows carbon emission has consistent impact on industrial production over time, whereas, industrial production has high impact on emission in the short run which fades in the long run which is consistent with Environmental Kuznets Curve (EKC) hypothesis. Carbon emission rising along with GDP per capita and at the same time having low impact in the long run on industrial index indicates there may be other sources of pollution introduced with the rise in income of the economy over time.

• 한국세라믹학회지
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• 제33권1호
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• pp.83-91
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• 1996

Monolithic AlN and AlN-W composites were fabricated by pressure-less sintering at 190$0^{\circ}C$ under nitrogen atmosphere and the influences of tungsten phase on the microstructure and mechanical properties were investi-gated. In the fabrication of sintered specimen no additive was used. And monolithic AlN showed substantial grain growth and low relative density. AlN-W composites were fully densified and grain growths of matrix were inhibited. The densification behavior of composites were inferred to be achieved through the liquid phase sintering process such as particle-rearrangement and solutino-reprecipitation. Also the oxid phases which is expected to form liquid phases duringsintering process were detected by XRD analysis. As the tungsten volume content increases fracture strength was decreased and fracture toughness was increased. It was suppo-sed that the strength decrease of composites with tungsten content was due to existence of interface phases. The subcritical crack growth behavior was observed from the stress-strain curve of composites. The effect of the secondary phase and interface phases on toughness in crease were studied through observation of crack propagation path and the influence of residual stress on crack propagation was investigated by X-ray residual stress measurement. In the result of residual stress measurement the compressive stress of matrix in composi-test was increased with tungsten volume content and the compressive stress distribution of matrix must have contributed to the inhibition of crack propagation.

• International Journal of Oral Biology
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• 제38권2호
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• pp.81-85
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• 2013

There are estimated to be about 700 species of bacteria in the oral cavity. Based on epidemiological investigations, some of these strains have been proposed as the pathogens responsible for oral diseases such as dental caries, gingivitis and periodontitis. Since electrolyzed hydrogen-rich water has been shown to have beneficial effects on human immunity, its use has increased. In our study, the antibacterial activity of hydrogen-rich water for oralagainst bacteria associated with oral disease was evaluated. The bacterial strains Streptococcus mutans, Fusobacterium nucleatum, Porphyromonas gingivalis and Tannerella forsythia were cultured in specific growth medium. S. mutans, F. nucleatum and P. gingivalis were soaked to thein both hydrogen water and tap water for 30 sec and then inoculated onto mitis-salivarius agar and brain heart infusion agar including supplemented withvitamin K and hemin, respectively. The numbers of bacterial colonies were then measured after cultivation for 48 hours. In the case of T. forsythia, which does not grow well on agar plates, inoculations into modified new oral spirochete (NOS) broth were performed and growth curve analysis was undertaken every day with a spectrophotometer. Hydrogen water showed antibacterial activity against all four bacterial strains in comparison with tap-water. We conclude from this that hydrogen water may have a positive impact on oral hygiene by helping to remove cariogenic bacteria and periodontopathogens.

• 아동학회지
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• 제36권4호
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• pp.91-110
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• 2015

In upper elementary period school adjustment and the effect of parenting face a new set of dynamics. We assumed that parental supervision, affection, incoherence, over-expectation, over-interruption and logical explanation would have an effect on individual trajectories in the development of school adjustment. Additionally, we hypothesized that this model would be different among boys and girls. In this study we analyzed three waves of data collected from 2,378 children nationwide in South Korea. This data was gathered from the Panel Study of Korean Youth and Adolescents conducted by the National Youth Policy Institute(NYPI). Growth-curve longitudinal analysis was conducted and the results indicate that levels of school adjustment had decreased through the $4^{th}$ to $6^{th}$ grade. Parents' supervision, affection and logical explanation significantly predict children's initial school adjustment as well as their rate of decrease in their levels of school adjustment. Parents' supervision had a positive effect on girls' school adjustment. Parents' over-expectation had negative effect on boys' school adjustment levels. Policy implications and future directions for research were also discussed.

• 한국기후변화학회지
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• 제7권4호
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• pp.493-498
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• 2016

This study was conducted to investigate the effect of environment factors on full bloom stage and fruit width in four peach cultivars. The average temperature in March was the main factor to determine the date of full bloom in 'Kurakatawase'($-0.6871^*$) and 'Changhowon Hwangdo'($-0.5270^*$). The fruit growth curve after 35 days from full bloom was the double sigmoid shape in 'Changhowon Hwangdo' cultivar. Environmental factors affecting fruit width were mean diurnal range(BIO2) and temperature annual range(BIO 7) in 'Kurakatawase', growing degree days(GDD) after 30 days from full bloom and July precipitation in 'Yumyeong', and annual mean temperature(BIO1), BIO7, and July precipitation in 'Kawanakajima Hakuto'. Of these, major environmental factors affecting fruit width in more than two cultivars were BIO7 and July precipitation.