• KIEAE Journal
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• 제9권1호
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• pp.39-45
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• 2009

The lateral pressure that functions on the form of the rammed earth method occupies an important part in the construction of the form. The following research constructed testing forms of $800mm{\times}1200mm$, that have the wall thickness of 200mm, 300mm, 400mm and 500mm to measure the lateral pressures according to the wall thicknesses. Research showed that compared to the concrete construction lateral pressures, the form results measured 2.3-8.9 times higher, and rather than thickness of the form, the distance between the rammer and mold and assuring time had direct relation to the lateral pressure of the form.

• 대한가정학회지
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• 제38권12호
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• pp.145-158
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• 2000

The purpose of this study was to examine the relative importance of parental expectations to adolescents'psychological, behavioral, school-based adjustment, and academic achievement. Subjects of this study consisted of 359 adolescents(177 boys and 182 girls) in Cheong-ju City. There was a statistically meaningful difference in the effect of parental expectations of academic performance on adolescents'adjustment according to sex of adolescents'. Maternal pressure, support form mothers, and paternal pressure were significant factors predicting adolescents'relative psychological adjustment and academic achievement. Support and pressure from mothers were associated with adolescents'behavioral adjustment. The research suggest that maternal pressure was the strongest risk factors in relation to the effects of parental expectations of academic performance on adolescents'adjustment.

• 한국세라믹학회지
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• 제29권2호
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• pp.136-142
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• 1992

The effects of cyclic stress, frequency and bias-pressure on densification of Al2O3 powder cyclic compaction are investigated. The effect of frequency was not significant on densification of Al2O3 powder under cyclic compaction. The higher the cyclic stress and the lower the bias pressure, the higher densification was achieved. To obtain a higher densification, cyclic compaction was more efficient than 1 stroke compaction. A densification equation was proposed to describe an cyclic time dependent pressure-volume relation for Al2O3 powder under cyclic compaction. This equation was obtained empirically, based on the pressure-volume equation proposed by Cooper and Eaton, the time dependent densification equation by Kim and Suh and experimental data for Al2O3 powder under cyclic compaction. The agreement between the proposed equation and experimental data for Al2O3 powder under cyclic compaction was very good.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2012년도 제38회 춘계학술대회논문집
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• pp.515-519
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• 2012

Lapple 방식의 사이클론 내부유동 특성과 작동온도와의 연관성이 수치해석적으로 관찰되었다. 수치계산의 결과는 과거 실험적/수치해석적 연구결과와 좋은 일치를 보였다. 사이클론 작동온도의 상승으로 벽면전단응력과 접선방향속도가 감소되어 압력손실이 저감되는 것이 관찰되었으며, 아울러 다양한 작동온도 조건에서 수치해석의 결과와 이론적 예측모델들의 압력손실 결과가 비교 분석되었다.

• Journal of Preventive Medicine and Public Health
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• 제24권2호
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• pp.161-170
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• 1991

The purpose of this study is to find the tracking of blood pressure in primary school-age children. A follow-up study was conducted from 1986 to 1990 on 330 first grade children attending primary schools in Kangwha County, Kyungki-Do. Basically we employed a linear regression model with random coefficients to figure out the relation between blood pressure changes and initial blood pressure. We obtained the following results ; 1. The mean blood pressures were increased grade went up in both sexs and were generally higher in female than male except for the systolic blood pressure at first grade. The size of difference was about 0.8 mmHg in mean systolic blood pressure and 1.5 mmHg in mean diastolic blood pressure. 2. The average annual increasing rates of systolic blood pressure were 2.5 mmHg in male and 3.1 mmHg in female respectively. For the diastolic blood pressure IV the average annual increasing rates were observed to be 3.0 mmHg in male and 2.9 mmHg in female respectively. Increasing rate of systolic blood pressure was significantly higher in female than male. 3. The adjusted regression coefficient of systolic blood pressure change on initial value was -0.11 in male and -0.13 in female and that coefficient of diastolic blood pressure change on initial value was -0.01 in male and -0.11 in female. This result shows that children with higher initial blood pressure do not pick up their blood pressure faster than others with lower initial blood pressure. There is no evidence of tracking of blood pressure in children. It is essential to find the earliest age having the tracking of blood pressure and we leave it for the further study.

• 한국식품영양과학회지
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• 제24권6호
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• pp.829-836
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• 1995

우리나라 농촌 성인 남녀의 납 섭취량, 혈중 농도, 소변 중 배설량과 혈압, 혈청 지질수준과의 관계를 알아보기 위하여 농촌에 거주하고 신체 건강한 성인 남녀 30명을 대상으로 신체계측, 3일간의 식이섭취조사 및 식이와 소변수거, 혈액체쥐를 통해 납의 섭취량, 혈중농도, 소변 중 배설량과 혈압 및 혈청 지질 함량을 측정하고 이들간의 관계를 살펴본 결과는 다음과 같다. 연구 대상자들의 평균 납 섭취량, 혈중 수준 및 뇨중 배설량은 각각 $226.1{\pm}263.8\mu\textrm{g}/day,\;10.8{\pm}3.6\mu\textrm{g}/dl\;및\;36.5{\pm}9.5\mu\textrm{g}$이었다. 수축기와 이완기 혈압은 $113.0{\pm}16.9mmHg와\;76.7{\pm}12.1mmHg$였고, 혈청 총콜레스테롤, 중성지질, HDL-콜레스테롤, LDL-콜레스테롤 및 ${\beta}-lipoprotein$ 함량은 각각 $158.8{\pm}32.9mg/dl,\;104.6{\pm}48.8mg/dl,\;45.7{\pm{9.9mg/dl,\;92.2{\pm}28.5mg/dl\;및\;426.4{\pm}141.5\;mg/dl$인 것으로 나타났다. 납의 섭취량, 혈중 수준 및 뇨중 배설량과 혈압간에는 유의한 상관성이 나타나지 않았으나 납 섭취량과 에너지 및 당질 섭취량간에 유이한 정의 상관성이 있었다. 납과 혈청 지질수준과의 관계에서 납 섭취량과 HDL-콜레스테롤 함량간에 유의한 부의 상관성이 나타난 납의 섭취로 동맥경화 발생의 가능성이 높았으며 납과 그밖의 지질간에는 유의한 상관성이 없었다. 본 연구는 조사 지역과 규모면에서 많은 제한점이 있지만 앞으로 본 연구를 기본으로 다양한 지역과 납의 노출수준이 다른 많은 대상자 및 다양한 중금속을 비교 분석할 수 있는 다각적인 연구가 필요하다고 생각한다.

• 산업기술연구
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• 제21권A호
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• pp.317-327
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• 2001

For soils with high void ratios, the inverse method of utilizing results obtained from centrifuge model test was used to find the constitutive relation of effective stress - void ratio - permeability whereas conventional oedometer test and constant rate of strain consolidation test were also used to fine its relation at ranges of relatively low void ratio. Results of column test about settlement of interface and pore pressure and distribution with time were compared with numerically estimated values to confirm such a constitutive relation as obtained from the inverse method. Consolidational settlement in dredged and reclaimed ground, where the consolidation was in progress, was predicted by using the numerical technique implemented with the finite strain consolidation theory.

• 한국연소학회지
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• 제16권2호
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• pp.16-22
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• 2011

It is a challenging task to apply large detailed chemical mechanisms of fuel oxidation in simulation of complex combustion phenomena. There exist a few systematic methodologies to reduce detailed chemical mechanisms to smaller sizes involving less computational load. This research work concerns generation of a skeletal chemical mechanism by a directed relation graph with specified accuracy requirement. Two sequential stages for mechanism reduction are followed in a perfectly stirred reactor(PSR) for high temperature chemistry and to consider the autoignition delay time for low and high temperature chemistry. Reduction was performed for the detailed chemical mechanism of n-heptane consisting of 561 species and 2539 elementary reaction steps. Validation results show acceptable agreement for the autoignition delay time and the PSR calculation in wide parametric ranges of pressure, temperature and equivalence ratio.

• 동력기계공학회지
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• 제18권5호
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• pp.66-73
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• 2014

This study was considered to occur the local wall thinning at elbow which is flowing the steam and high-pressure water of high-temperature. The angle of elbow is ${\Theta}=45^{\circ}$ and $67.545^{\circ}$. The damage behaviors of inner or outer wall thinning elbow under internal pressure were calculated by FEA(finite element analysis). We compared the simulated results by FEA with experimental data. The FEA results are as follows: In the FEA results of three types of wall thinning ratio, the circumferential and longitudinal stresses show the similar values regardless of the angle of elbow, respectively. The circumferential strain was greater at elbow of small angle, but the longitudinal strain was nearly same. The FEM stress of outer wall thinning elbow was slightly higher than that of the inner wall thinning elbow, and strain was also slightly higher. In the experiments, the circumferential strain was increased with the increase in the internal pressure, and increased rapidly on about 0.2% of strain. The longitudinal strain was small. The strain at break was much smaller than 0.2%. In the relation between pressure and eroded ratio, the criteria that can be used safely under operating pressure and design pressure were obtained. The results of FEA were in relatively good agreement with those of the experiment.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 동계학술발표대회 논문집
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• pp.591-596
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• 2005

The objectives in the present study are to investigate that the enhancement heat transfer was experimentally measured and was compared with the acoustic pressure obtained by numerical analysis. From the results of the present study, a strong Fluid motion initiated by ultrasonic vibrations can affect heat and mass transfer. This phenomenon. called acoustic streaming, clearly observed by PIV measurement leads to increase in velocity of a Fluid which is a crucial physical concept to explain the enhancement heat transfer. The heat transfer coefficient is increased with increase in the ultrasonic intensities. The largest enhancement heat transfer (about 26%) is measured at the ultrasonic intensity of 300W. Acoustic streaming results from sudden acoustic pressure variations in the liquid. The results of numerical analysis reveal that acoustic pressure is increased by 59.5% at the ultrasonic intensity of 300W. The higher acoustic pressure near four ultrasonic transducers develops more intensive flow destroying the flow instability. Also, the profiles of acoustic pressure variation are consistent with those of enhancement heat transfer.