• 한국양식학회지
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• 제15권2호
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• pp.79-86
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• 2002

This study is the first attempt to understand the feeding physiology of a sea-urchin larva on a red-tide dinoflagellate. Fifteen day old larvae of S. intermedius capture C. polykrikoides cells by localized reversal of ciliary beats. No failure to transporte the algal cells from theciliated band to mouth and no rejection at the mouth suggest that C. polykrikoides has no feeding deterrence to S. intermedius larvae. The trend obtained for the clearance rate of S. intermedius larvae is similar to that of other sea urchin larvae. Thus, the clearance rate decreased as the algal concentration increased. Maximum clearance rate of S. intermedius on C. polykrikoides was 17.7 $\mu l$/larva/hr. Ingestion rate rapidly increased at lower algal concentrations and saturated at higher concentrations. There was no inhibition in ingestion rate at the highest prey concentration of ca. 3000 cells/ml. Maximum ingestion rate of S. intermedius on C. polykrikoides was 131 ngC/larva/d, which is higher than that reported for the larvae of the mussel Mytilus gal-lotrovincialis, but lower than that of the ciliate Strombidinopsis sp. The grazing rate, calculated by combining the field data on algal abundances with experimental data on ingestion rate, suggests that due to its low abundance, sea urchin Iarva has no significant grazing impact on C. polykrikoides population.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 1998년도 유체기계 연구개발 발표회 논문집
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• pp.240-247
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• 1998

Leakage vortices formed near blade tip causes an increase of total pressure loss near casing endwall region and as a result, the efficiency of rotor decreases. The reduction of rotor efficiency is related to the size of tip clearance. In this study, the three-dimensional flowfields in an axial flow rotor were calculated with varying tip clearance under various flow rates, and the numerical results were compared with experimental ones. The effects of tip clearance and attack angle on the leakage vortex and overall performance, and the less distributions were investigated through numerical calculations. In this study, tip leakage flow rate and total pressure loss by tip clearance were evaluated using numerical results and aprroximate equations were presented to evaluate the reduction of rotor efficiency by tip leakage flow.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.240-243
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• 2008

In this paper, the design of Centrifugal Compressor which is used in sizes 50 horse power has 8 pressure ratio and numerical analysis of the flow within compressor varying tip clearance length are performed. To get high pressure ratio with low power the exit height of impellers is low but compressor has very high speed of revolution. So compressor has high specific speed although mass flow rate is very small. The shape of impellers at the first stage is carried out. Flow and performance characteristics of impellers has been analyzed by using a commercial CFD program, $Fine^{TM}$/turbo. The result shows that loss coefficient is affected by tip clearance length and compressor has proper tip clearance length. It is possible to decrease loss by selecting apt tip clearance length.

• 대한한방내과학회지
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• 제1권1호
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• pp.92-97
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• 1976

Upon feeding dried Ginseng to rats of either low-protein or high protein diet ethanol was administered intraperitoneally and disappearance rate blood alcohol was enzymatically measure. In terms of residual blood alcohol after a time lapse of 3.5 hours between intraperitonial administration and blood withdrawal neither ginseng nor ginseng plus 40% casein did improve the rate, of alcohol clearance but sexual difference was clearly demonstrated in favor of female rats. In the case of blood withdrawn only 2 hours after intraperitoneal injection of alcohol, the tendency of female superiority in alcohol clearance rate is demonstrated when a comparison is made among the groups fed with ginseng and this was particularly true is groups of rats fed with basal diet plus 1 percent ginseng residual blood ethanol being 15.4 mg/ml vs. 8.8 mg/ml. Liver homogenate alcohol dehydrogenase activity measured in terms of residual ethanol content after in vitro reaction on which a known amount of alcohol was added clearly demonstrated a male superiority in alcohol clearance.

• 한국패류학회지
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• 제30권2호
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• pp.101-106
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• 2014

인공종묘로 생산된 동죽, Mactra veneriformis의 크기, 수온, 염분 변화에 대한 여수율과 먹이섭이량의 차이를 조사하였다. 수온의 경우 소형, 대형그룹의 여수율은 $5^{\circ}C$에서 최소값을 보였으며 $20^{\circ}C$에서 가장 높은 값을 보였으나, $25^{\circ}C$에서 급격한 감소 경향을 보였다. 염분에 대한 소형그룹의 여수율은 26‰에서 가장 높은 값을 보였고 8‰에서 가장 낮은 값을 보였다. 대형그룹은 32‰에서 가장 높은 값을 보였고, 8‰에서 가장 낮은 값을 보였다. 본 연구를 통해 동죽의 최적 수온, 염분 환경은 $20^{\circ}C$, 27-32‰이며, $10^{\circ}C$ 이하 또는 $25^{\circ}C$ 이상의 수온과 20‰ 이하의 저염분에서 여수율이 낮아진다는 사실을 확인할 수 있었다.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제17권1호
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• pp.41-46
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• 2014

Purpose: The spontaneous seroconversion rate of hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) virus infection in children is lower than that in adults. However, few studies have investigated the rate of transition from the immune-tolerant to the early immune-clearance phase in children. Methods: From February 2000 to August 2011, we enrolled 133 children aged <18 years who had visited the Department of Pediatrics, Kyungpook National University Hospital. All subjects were in the immune-tolerant phase of HBeAg-positive CHB virus infection. The estimated transition rate into the early immune-clearance phase was calculated using the Kaplan-Meier method. Results: Among the 133 enrolled pediatric CHB virus infection patients in the HBeAg-positive immune-tolerant phase, only 21 children (15.8%) had converted to the early immune-clearance phase. The average age at entry into active hepatitis was $10.6{\pm}4.8$ years. The incidence of transition from the immune-tolerant to the early immune-clearance phase in these children was 1.7 episodes/100 patient-years. When analyzed by age, the estimated transition rate was 4.6%, 7.1%, and 28.0% for patients aged <6, 6-12, >12 years, respectively. Conclusion: In children with CHB virus infection, the estimated rate of entry into the early immune-clearance phase was 28.0% for patients aged 12-18 years, which was significantly higher than that observed for children aged <12 years (11.7%; p=0.001).

• 한국유체기계학회 논문집
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• 제2권1호
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• pp.73-80
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• 1999

Leakage vortices formed new blade tip causes an increase of total pressure loss near the casing endwall region and as a result, the efficiency of rotor decreases. The reduction of rotor efficiency is related to the size of the tip clearance. In this study, the three-dimensional flowfields in an axial flow rotor were calculated by varying the tip clearance under various flow rates, and the numerical results were compared with experimental ones. The effects of tip clearance and attack angle on the leakage vortex and overall performance, and the loss distributions were investigated through numerical calculations. In this study, tip leakage flow rate and total pressure loss by tip clearance were evaluated using numerical results and approximate equations were presented to evaluate the reduction of rotor efficiency by tip leakage flow.

• 대한기계학회논문집B
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• 제23권9호
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• pp.1113-1120
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• 1999

Leakage vortices fonned near the blade tip cause an increase of total pressure loss near the casing endwall region and as a result, the efficiency of rotor decreases. The reduction of rotor efficiency is related to the size of tip clearance. In this study, the three-dimensional flow fields in an axial flow rotor were calculated with varying tip clearance under various flow rates, and the numerical results were compared with experimental ones. The effects of tip clearance and the of attack on the leakage vortex and overall performance, and the los9 distributions were investigated through numerical calculations. In this study, tip leakage flow rate and total pressure loss due to the tip clearance were evaluated using numerical results and approximate equations were presented to evaluate the reduction of rotor efficiency due to the tip leakage flow.

• 한국패류학회지
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• 제21권1호
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• pp.41-46
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• 2005

A series of radiotracer studies were conducted to evaluate the influence of water temperature and/or body size on the clearance rates and uptake rates of Cd, Se and Zn in the Asiatic clam, Corbicula fluminea, Asian clam Potamocorbula amurensis and Balthic clam, Macoma balthica. Uptake rates of Cd, Se and Zn were estimated simultaneously with clearance rate of clams under 3 different water temperature conditions (5, 13 and $21^{\circ}C$). The weight specific clearance and metal uptake rates of P. amurensiswere increased with temperature, however, no consistent temperature effect was observed for the other clams. The variation of uptake rates of Cd, Se and Zn along with temperature or body size in each clam species was well associated with clearance rates. The inter-species as well as the intra-species difference of metal uptake rates could be well explained by the variation of clearance rates of clam individuals.

• 대한기계학회논문집
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• 제17권7호
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• pp.1700-1709
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• 1993

The stepped specimen which is subjected to step loading is modeled to study the initiation and growth of adiabatic shear band using explicit time integration finite element method. Three different clearance sizes are tested. The material model for the stepped specimen includes effects of strain hardening, strain rate hardening and thermal softening. It is found that the material inside the fully grown adiabatic shear band experiences three phase of deformation, (1) homogeneous deformation phase, (2) initiation/incubation phase, and (3) fast growth phase. The second phase of deformation is initiated after sudden shear stress drop which occurs at the same time regardless of the clearance size. The incubation time prior to fast growth phase increases, as the clearance size of the stepped specimen increases. Whereas, after incubation period, the growth rate of the adiabatic shear band decreases, as the clearance size decreases. It is also found that two adiabatic shear band may develop instead of one for the smaller clearance size.