• 대한토목학회논문집
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• 제28권6A호
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• pp.765-778
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• 2008

리스크 관리에 기반한 교량관리를 위해서는 시간 및 환경에 따른 성능변화를 예측하기 위한 성능이력모델이 필수적이다. 일반적으로 성능이력모델의 산출은 어려운 작업이므로 전문가 의견 또는 교량의 겉보기 상태 진단평가 기록을 이용한 상태 성능 이력모델이 많이 사용되어 왔다. 하지만 상태성능 이력모델은 교량의 실제 안전도와는 일치하지 않은 경우가 많아 근본적인 문제를 내포하고 있다. 성능 평가 및 이에 따른 성능이력모델의 정확도는 교량 유지관리 시스템(Bridge Management System, BMS)의 정확도와 직접적인 관계가 있으며 유지관리 예산의 합리적인 분배를 위한 최적 대안 산출을 위해 매우 중요하다. 본 연구에서는 기존의 방법, 즉 정성적 전문가 의견 및 불충분한 정기점검 기록에 의해 작성되는 상태 성능 이력모델의 단점을 극복하기 위하여 열화를 고려한 수치해석결과를 바탕으로 산출되는 안전성능이력모델을 제안하였다. 제안한 성능이력모델 구축을 위해서 다양한 교량 형식이 검토 되었으며, 그 중 설계 변수 간 종속성이 높아 고려되어져야 할 설계 변수의 수가 비교적 적은 강박스 교량을 중심으로 다양한 환경 조건 및 시간에 따른 안전성능이력의 변화를 분석하였다. 교량 유지관리 시스템 내에서의 안전성능 이력모델의 역할은 특정 환경 하에서 시간에 따른 안전성능변화 예측에 있으며 안전성능이력모델의 산출 속도는 시설물 관리시스템의 효율성에 직접적인 영향을 미치기 때문에 일반적으로 실시간 해석을 수행하기 보다는 기 작성된 예측모델을 사용하는 방법이 주로 사용된다. 본 연구에서는 정량적 성능이력의 신속한 산출을 위하여 주요 설계 변수로 구성된 응답면 기법(Response Surface Method, RSM)을 사용하였다. 응답면 기법 적용을 위한 설계 변수 및 설계 값의 범위는 국내 강상자형교 설계 기준, 가이드라인 및 유지관리 자료를 근거로 산정하였다.

• Journal of the korean society of oceanography
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• 제32권2호
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• pp.63-68
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• 1997

Stable isotope profiles with fine-scale resolution were constructed from the fossil mollusk shells, Mercernaria mercernaria, obtained from the late Pleistocene transgressive deposits of Gomez Pit, Virginia, USA. Incremental sampling were made along the axis of maximum growth to provide high-resolution ${\delta}^{18}$O and ${\delta}^{13}$C records. The ${\delta}^{18}$O shell profiles exhibit a series of pronounced cycles in the overall amplitude, corresponding to strong seasonal variations in temperature, which is apparently positive environmental variable. Contrasts between the patterns of ${\delta}^{18}$O and ${\delta}^{13}$C profiles reflect the relationship influencing the seasonal carbon cycling in the shallow marine environment. Positive anomalies of the ${\delta}^{13}$C values during the summer were observed to be out of phase with the ${\delta}^{18}$O profile. Such relatively heavier carbon source may be alternated due to seasonal methanogenesis during the summer. A hypothesized methane-based system may be operated in the shallow and marginal marine environment, resulting in a ${\delta}^{13}$C enriched bicarbonate pool, in which the heavier isotope seems to be incorporated to the shell carbonate.

• 한국해안해양공학회지
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• 제14권3호
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• pp.222-231
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• 2002

ADP는 음향의 Doppler효과를 이용하여 층별 유속과 유향을 측정하는 장비이며, 최근에는 반사음향의 강도로부터 부유 퇴적물의 농도측정이 가능하다고 제기되고 있다. 본 연구에서는 염산 인근의 한 정점에 ADP 기기를 설치하고 자료를 수집하였다. 부유사 농도를 분석하기 위하여 해수 분석을 통한 음향계수를 정한 후 보정된 음향강도를 이용하여 부유사 농도를 구하였다. 관측된 부유사 농도분포 식은 해석해와 비교하였으며, 농도변화의 경향에 대해서는 비교적 양호한 결과를 나타냈다. 또한, 관측기간 동안의 부유물질의 이동량에 대한 정량적 결과를 얻었으며 ADP를 활용한 연직방향의 부유입자 농도변화를 관측할 수 있음을 보였다.

• 한국추진공학회지
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• 제2권2호
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• pp.30-37
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• 1998

연소 반응을 가지는 비압축성 및 압축성 후류유동에 대하여 선형 불안정성 해석을 수행하였따. 기본유동의 속도장 및 온도장은 해석적 함수 및 연소 반응을 포함하는 유동 계산의 결과를 사용하였다. 후류유동은 두 개의 변곡점을 가지며 sinuous mode와 varicose mode의 두 개의 불안정성 모드가 존재한다. 후류유동에서는 sinuous 모드가 varicose 모드보다 더 불안정하여 자유 유동에 가까운 위상 속도를 가지는 sinuous 모드에 의해 지배된다. 해석적 함수의 형태를 가지는 후류 유동의 경우 속도구배가 클수록, 밀도구배가 클수록 운동량의 차이가 커지므로 더욱 불안정하여진다. 계산되어 일관된 유동장과 온도장을 사용한 비압축성과 압축성 후류유동의 경우 모두 완전연소에 가까울수록 유동장의 온도가 증가하고 유체의 점성의 증가로 유동이 안정되어진다. 압축성 후류유동의 경우에는 유속이 증가함에 따라 점성소산에 의한 열발생으로 유동이 안정되는 경향을 보인다.

• 한국식품영양과학회:학술대회논문집
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• 한국식품영양과학회 2004년도 Annual Meeting and International Symposium
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• pp.73-79
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• 2004

The large-scale preparation method for black soybean peptide (BSP; about 70% less than 10,000 Da; highly enriched with glutamic acid, aspartic acid, and arginine) was developed, and its effect on weight reduction and lipid profiles in rats was investigated. Sprague-Dawleymale rats were assigned to four dietary groups (high-fat diets containing 0, 2, 6, and 10% BSP) and fed four weeks to examine the effects of BSP. During the experiment, food intake was measured every two days and body weight was monitored two times a week. After the supplementation of BSP, liver and adipose tissues (epididymal, retroperitoneal and perirenal adipose tissue) in the rats were weighted and the lipid profiles in serum, liver, and feces were analyzed. At the results of body weight gain, liver and epididymal adipose tissue weight, BSP groups were more decreased than HF group (0% BSP), with greater decreases at higher BSP levels. The same patterns were shown in lipid profiles of serum, as BSP was increased, triglyceride and total cholesterol concentration decreased. The serum HDL-cholesterol level was increased with increasing at BSP levels. Total cholesterol concentration of liver and feces were decreased and increased, respectively, as BSP increased. The results confirm that BSP is involved in reducing the body weight and the improvement of lipid composition in serum and liver of rats and that BSP can be applied in weight reduction in the food products industry.

• 한국유체기계학회 논문집
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• 제5권4호
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• pp.54-60
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• 2002

Experimental study was conducted to obtain the air velocity profiles in turbulent pipe flow. The acrylic smooth pipe (${\phi}=80mm$) was used for the test section of the flow loop. It was known that the velocity profiles of turbulent flow were different with Reynolds numbers and the viscous sublayer was usually quite thin. The following conclusions were drawn from the experimental investigations. Maximum velocity of the pipe center and flow-rate are useful for the duct design on the spot. The velocity profiles of high Reynolds number was flatter than those of low Reynolds number. It was known that the exponent, n, for power-law velocity profiles was $6{\sim}9$ depending on Reynolds number ranging from $10^4$ to $10^5$ in the turbulent flow, However, in this experiment study, it was $9{\sim}14$ depending on Reynolds number ranging from 17,000 to 123,727 in the turbulent flow, and $1.7{\sim}3.5$ depending on Reynolds number ranging from 2,442 to 4,564 in the transition region.

• International Journal of Vascular Biomedical Engineering
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• 제1권1호
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• pp.24-31
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• 2003

As endothelial cells are subject to flow shear stress, it is important to determine the detailed velocity distribution in microvessels in the study of mechanical interactions between blood and endothelium. This paper describes a velocity field of the arteriole in the rat mesentery using an intravital microscope and high-speed digital video system obtained by a highly accurate PIV technique. Red blood cells (RBCs) velocity distributions with spatial resolutions of $0.8{\times}0.8{\mu}m$ were obtained even near the wall in the center plane of the arteriole. By making ensemble-averaged time-series of velocity distributions, velocity profiles over different cross-sections were calculated for comparison. The shear rate at the vascular wall also evaluated on the basis of the ensemble-averaged profiles. It was shown that the velocity profiles were blunt in the center region of the vessel cross-section while they were steep in the near wall region. The wall shear rates were significantly small, compared with those estimated from the Poiseuille profiles.

• Journal of Nutrition and Health
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• 제36권7호
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• pp.667-674
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• 2003

The study was performed to investigate the effects of isoflavone and/or grape seed oil supplementation on serum and liver lipid profiles and bone strength in ovariectomized female rats. Female Spraque-Dawley rats were assigned into 4 groups of ovariectomized (O), isoflavone (0.085 mg/100 g b.w/day) in ovariectomized rats, grape seed oil in ovariectomized rats and isoflavone and/or grape seed oil in ovariectomized rats. After 8 weeks, biochemical profiles of serum, liver and bone were analyzed. Total food intakes, body weight gains and FER (food efficiency ratio) were not statistically significantly different among groups. Total cholesterol, triglyceride and LDL-cholesterol levels in serum were decreased by fed of isoflavone and/or grape seed oils. However, crude lipid and total cholesterol contents in liver were not affect of isoflavone and/or grape seed oil. The hepatic glutathione contents were increased by isoflavone and/or grape seed oil fed. The hepatic glutathione-S-transferase activity in isoflavone and/or grape seed oil supplemented groups were higher than that O group. Bone (scapular and femur bone) dry weight, femur of max weight and bending strength were no significant difference among groups. Our finding suggest that isoflavone/grape seed oils might have potential role for serum lipid profiles improvement and bone strength in vivo.

• Nutrition Research and Practice
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• 제1권2호
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• pp.84-88
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• 2007

The purpose of this study was to identify dietary patterns among children and adolescents in Korea and to examine their associations with obesity and some blood profiles. One day food consumption data measured by 24-hour recalls on 2704 subjects aged 1 to 19 were used from 2001 Korea National Health and Nutrition Survey. The data of blood profiles available in the ages of 10 or older was also used. After categorizing each food consumed into 29 food or food groups, five dietary patterns were derived through a factor analysis and subjects were classified into three major dietary patterns via a cluster analysis using the factor scores. Three dietary patterns were identified as 'traditional diet' (25.6%), 'westernized-fast food' (6.2%), and 'mixed diet' (68.2%). The 'traditional diet' pattern had a higher percentage in boys. Both the 'traditional diet' and the 'westernized-fast food' had higher proportions of adolescents (12-19 y) than younger children, while the 'mixed diet' had a higher percentage of preschool children (1-5 y). Obesity rate analyzed within each age group showed no differences among 3 dietary pattern clusters. Blood pressure and all plasma profiles were not different among dietary patterns when adjusted with age and gender. Conclusively, children and adolescents in Korea had three distinct dietary patterns, which were associated with gender and age. These patterns could be useful to plan nutrition interventions for teenager health promotion.

• Journal of Nutrition and Health
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• 제38권9호
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• pp.698-705
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• 2005

The purpose of this research was to investigate the effect of the boron supplementation on lipid profiles and antioxidant capacities in ovariectomized (OVX) rats. Rats were divided into 3 groups and fed diet with intake levels of boron (0.5 ppm,50 ppm,100 ppm) for 4 weeks. The half of rats in each group was ovariectomized and the others were sham-operated. And rats were fed same diets for 8 weeks after operation. Feed intake and weight gain were significantly increased by increasing boron intake and higher in OVX group than those in sham-operated. FER was significantly higher in OVX group than that of sham-operated. There were no significant differences in serum lipid profiles among the groups. The contents of hepatic total lipid were significantly higher in OVX group than those of sham-operated and the lowest in high-boron group. Hepatic GST activity was significantly decreased by ovariectomy and the lowest in very high-boron group. Hepatic catalase activity was the lowest in high-boron group of OVX. Hepatic TBARS level of high-boron group was the lowest in sham-operated groups. Hepatic TBARS level induced by AAPH was significantly decreased by increasement of boron supplementation. Taken together, this results suggest that the boron supplementation have the potential role for improving lipid profiles and antioxidant capacities in OVX rats.