• Journal of Nutrition and Health
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• 제27권6호
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• pp.574-582
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• 1994

The effects of age and dietary fatty acid composition on prostagladin production was investigated in Sprague-Dawley strain male rats. Animals weighing 88.6$\pm$2.2g were fed 10% dietary fat(W/W, 20% of total energy). The P/S ratios of dietary lipid were three levels(0.5, 1, 2) and there were three different levels of n-6/n-3 fatty acid ratio(2, 4, 8) in each P/S ratio. The experimental period were 1 month and 12 months, respectively. The results of this study were as follows. As the age of rats increased, the plasma thromboxane B2 production increased, but aorta 6-keto prostaglandin F1$\alpha$ decreased. When a higher amount of n-3 fatty acid was fed in each P/S ratio, the relative percentage of linolenic acid and EPA in platelet increased.

• Journal of the Korean Wood Science and Technology
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• 제49권4호
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• pp.287-298
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• 2021

Torch ginger (Etlingera elatior Jack) is a potential source of lignocellulose material for various derivative products. This study aims to determine the chemical components, ratio of syringyl to guaiacyl units (S/G) in lignin, and crystallinity of the biomass of torch ginger. The effects of soda pulping on the chemical characteristics of torch ginger pulp were also studied. Pulping of the chips was conducted with active alkali of 15%, 20%, and 25% and a Liquor-to-Wood (L/W) ratio of 4:1, 5:1, and 6:1. The impregnation and pulping times at maximum temperature (170℃) were 120 and 90 min, respectively. To assess the effect of treatments on the properties of pulping, a two-factorial experimental design was applied. Results showed that the content of α-cellulose and hemicellulose in the torch ginger was 48.48% and 31.50%, respectively, with an S/G ratio of 0.70 in lignin. Soda pulping changed the crystalline structure of the biomass from triclinic to monoclinic. Active alkali, L/W ratio, and interactions considerably influenced the observed responses. The degree of delignification increased with an increase in the loading of active alkali, which lead to a decrease in the kappa number of the pulp. An active alkali content of 25% and an L/W ratio of 6:1 resulted in the highest delignification selectivity with a kappa number of 2.78 and a yield of 24%. Given its cellulose content and ease of pulping, torch ginger can be a potential raw material for derivative products that require delignification as pretreatment. However, the increase in cellulose crystallinity should be considered when converting torch ginger to bioethanol.

• Journal of Nutrition and Health
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• 제27권7호
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• pp.687-698
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• 1994

The effects of age and dietary fatty acid composition on lipid metabolism were investigated in Sprague-Dawley strain male rats. These animals weighing 88.6$\pm$2.2g were fed 10% dietary fat(W/W, 20% of total energy) with 0.5, 1, 2 P/S ratio and in each P/S ratio there were three different levels of n-6/n-3 fatty acid ratio ; 2, 4, 8. The experimental period was 1 month, 6 months and 12 months. The results of this study were as follows. The body weight of rats increased rapidly for the first two months, then increased slowly until 7 to 8 months. After 10 months of dietary regimen their weight decreased. The weight of liver, kidney and epidydimal fat pad increased along with the body weight and then decreased in the 12 months. Plasma total lipid increased with age and it decreased significantly when P/S ratio of dietary fatty acid was high. In creased with age and it decreased significantly when P/S ratio of dietary fatty acid was high. In creasing n-3 fatty acid intake in each P/S ratio resulted in lower plasma total lipid although was not statistically significant. The amount of plasma total cholesterol increased at 6 months, but decreased at 12 months. In case of 1, 12 months, increasing P/S ratio significantly plasma total cholesterol and LDL-cholesterol were decreased and hepatic cholesterol was increased, VLDL-HDL-cholesterol did not changed. The n-6/n-3 ratio did not affect any of theses. The amount of plasma triglyceride and VLDL-triglyceride increased at 6 month then decreased. When the rats consumed higher amount of n-3 fatty acid in each P/S ratio, their plasma triglyceride and hepatic triglyceride increased at 1, 12months.

• 한국항공운항학회지
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• 제13권4호
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• pp.92-99
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• 2005

A closed-circuit type wind tunnel is designed, which has a test section with the dimensions $1.2(W){\times}1.2(H){\times}3.4(L)$. A subsonic wind tunnel is designed to improves educational circumstances and promote ground tests. It is constituted of an exchangeable test section, first and second diffusers, a fan, a settling chamber, a contraction, and 4 corners. The maximum velocity in the test section is 70m/s and the contraction ratio is 6.25:1. Input power in the wind tunnel is about 96.1 kw (128.8 hp) and its energy ratio is 3.89. It has the dimension of about $7.4(W){\times}3.6(H){\times}21.7m(L)$. The wind tunnel designed in this investigation will be an effective educational and investigational equipment.

• 대한기계학회논문집
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• 제4권3호
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• pp.113-118
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• 1980

Stresses were calculated for finite-width orthotropic laminates with a circular hole and remote uniaxial loading using a two-dimensional finite-element analysis with both uniform stress and uniform displacement boundary conditions. Five different laminates were analyzed: quasi-isotropic [0.deg./.+-.45.deg./90.deg.].$\_$s/, 0.deg., 90.deg., [0.deg./90.deg.]$\_$s/, and [.+-.45.deg.]$\_$s/, Computed results are presented for selected combinations of hole diameter-sheet-width ratio d/w and length-to width ratio L/w. For small L/w values, the stress-concentration factors K$\_$tn/ were significantly different for the uniform stress and uniform displacement boundary conditions. Typically, for the uniform stress conditions, the K$\_$tn/ values were much larger than for the infinite-strip reference conditions; however, for the uniform displacement conditon, they were only slighty smaller than for this reference. The results for long strips are also presented as width-correction factor. For d/w.leg.33, these width-correction factors are nearly equal for all five laminates.

• 한국구조물진단유지관리공학회 논문집
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• 제10권6호
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• pp.105-113
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• 2006

본 연구는 잔골재와 굵은 골재를 전량 플라이애쉬로 치환한 콘크리트의 공학적 특성을 밝히기 위한 실험적 연구의 결과이다. 그리고 플라이애쉬 전량 치환 콘크리트의 유동성 저하 문제를 추가수량($W_f$)으로 해결하고자 하였다. 실험은 물-시멘트 비($W_c/C$)를 0.35, 0.45 그리고 물-플라이애쉬 비($W_f/FA$)를 0.35, 0.45로 하였다. 플라이애쉬 치환은 P와 Q의 두 가지 방법으로 하였다. P 방법은 플라이애쉬와 첨가수량($W_f$)의 중량이 골재의 중량과 같은 배합법이다[$FA+W_f$ = G (또는 S)]. Q 방법은 플라이애쉬와 골재의 중량이 같고 첨가수량($W_f$)을 추가하는 배합법이다 [$FA+W_f$ > G (또는 S)]. 실험은 굳기 전 콘크리트의 특성과 3, 7, 28 및 91일 압축강도 특성을 측정하였다. 실험결과 압축강도는 $Wc/C=0.35$, $W_f/C=0.35$ 일 때, P 치환법 중에서 잔골재 치환이 다른 배합들보다 향상되었다. Q 방법은 P 방법에 비해 유동성은 향상되었으나, 압축강도는 그렇지 않았다. 실험결과는 잔골재와 굵은 골재를 플라이애쉬로 전량 치환한 콘크리트의 유동성과 강도 특성이 향상됨을 알 수 있었고, 플라이애쉬 치환방법으로 효과적임을 보여주었다.

• 한국유체기계학회 논문집
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• 제15권3호
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• pp.32-38
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• 2012

This paper is aimed to propose the design database(DB) of the inline micro-turbine for 5kW class. CFD analysis is performed to investigate the effect of a turbine on each parameter. This study showed that RadhaKrishna's data is different from the 5kW class in the low-head and the micro-turbine. Therefore, new DB for the design of inline micro-turbine for 5kW class could be needed. This study configured new design DB for the design of inline micro-turbine for 5kW class. The DB of this study showed that the optimal hub ratio(Dp/DR), the optimal body ratio(Db/DR) and the optimal range of body length ratio(Lh/DR) is 50%, 1.1 and 2.3 to 2.9, respectively.

• 대한화장품학회지
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• 제20권1호
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• pp.52-63
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• 1994

4성분계 o/w 형 microemulsion의 안정성과 유동특성에 비이온 계면활성제와 보조계면 활성제의 혼합비가 미치는 영향을 연구하였다. 비이온 계면활성제와 보조계면 활성제의 혼합비에서 계면활성제의 양이 증가함에 따라 입자의 크기가 작아졌고, 경시안정성이 양호하였으며, 이 때의 혼합비는 20/40 - 30/30으로 나타났다. Rheogram을 통하여 시료에는 일정한 내부구조가 형성됨을 의미하는 항복점이 존재함을 알 수 있었으며, 전단속도 증감 시 전단응력이 일치하지 않는 hysteresis를 나타내었다. hysteresis의 면적은 혼합비에서 계면활성제의 양이 많아짐에 따라 커졌으며 제조된 microemulsion은 rheopetic한 특성을 보였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
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• pp.143-150
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• 1997

The maturity concept was adopted to predict the strength of concrete, which was subjected to same temperature conditions and variable curing conditions. Penetration test and compressive test were conducted to measure the initial and final setting time and the compressible strength of concrete specimen, respectively. Also, the temperature and time were recorded at some intervals of time for calculating the maturity. The initial and final setting were delayed as the w/c ratio increased and curing temperature decreased. The activating energy decreased as the w/c ratio increased. The relationships at the relative strength and the maturity were proposed at different w/c ratio for the same temperature curing condition, and these were applied for the variable curing conditions. The results indicated that the difference between the strength of the proposed and the specimen was big at 1 days's age but quite similar after 3 day's age.

• International Journal of Automotive Technology
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• 제7권4호
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• pp.385-390
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• 2006

A fast response $CO_2$ analyzer has been developed to study transient characteristics on an SI engine. The analyzer has the delay time of 4.5 ms and time constant of 2.8 ms, which is fast enough to measure $CO_2$ concentration on a transient condition. Wide range of A/F(Air/Fuel) ratio can be estimated using the analyzer with an additional switch type oxygen sensor. The results of measurement of $CO_2$ concentration and A/F ratio on a transient condition including rapid acceleration/deceleration and EGR(Ehxaust Gas Recirculation) on/off are presented and compared with a commercial exhaust gas analyzer and UEGO(Universial Exhaust Gas Oxyzen) sensor.