• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.108-108
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• 2003

본 연구에서는 넙치(Paralichthys olivaceus)를 이용한 고ㆍ저온에서의 혈액 생리학적인 변화뿐만 아니라 항산화 효소인 CAT 및 SOD등의 효소 변화를 조사하여 스트레스에 대한 생리적인 변화에 대한 지표를 설정하고자 실시하였다. 실험어는 평균 전장의 29.0$\pm$1.5 cm, 평균 중량 246.5$\pm$25 g인 것을 사용하였다. 실험구는 각각 15$^{\circ}C$, 2$0^{\circ}C$(대조군), $25^{\circ}C$ 및 3$0^{\circ}C$로 설정하였으며, 실험 개시 후 1, 2, 4, 6 및 8 hr후에 혈액성상을 분석하였다. 측정항목으로는 헤마토크리트(Ht)수치, 혈색소 농도(Hb), 적혈구 수(RBC), 코티졸, Catalase (CAT) 및 Superoxide dismutase (SOD)를 각각 측정하였다. 실험결과 아가미 운동은 대조구에 비해 3$0^{\circ}C$ 및 $25^{\circ}C$ 에서 유의한 증가를 나타내었고, 저온인 15$^{\circ}C$ 및 1$0^{\circ}C$에서는 감소하는 결과를 보였다. Ht수치는 3$0^{\circ}C$에서 실험 개시 후 6시간까지 높은 값을 나타내었으며, $25^{\circ}C$에서는 1 시간까지는 증가하였다가 이후 6 시간까지는 감소되었다. 그러나 저 수온인 15$^{\circ}C$ 및 1$0^{\circ}C$에 서는 전체적으로 감소된 값을 나타내었다. RBC는 3$0^{\circ}C$ 및 $25^{\circ}C$에서 전반적으로 증가하였으며, 저 수온인 15$^{\circ}C$는 4 시간까지 낮아지다가 이후 증가 되었다. Hb농도는 3$0^{\circ}C$및 $25^{\circ}C$에서 전반적으로 증가하는 경향을 보였으나 4 시간째 일시적으로 감소하는 경향을 보였다. 15$^{\circ}C$에서는 4시간째까지는 감소되었다가 6 시간째에는 높아지는 경향을 보였다. 이러한 증가된 경향은 온도가 높아질수록 용존 산소의 포화도가 낮아져 산소부족 요인에 의해 적혈구수의 증가와 함께 Ht수치도 높아지며 아가미운동을 통한 혈액으로의 산소운반이 능동적으로 이루어지고 있음을 나타내고 있다. 혈장 코티졸의 농도는 $25^{\circ}C$에서는 증가하는 경향을 보였으며, 1$0^{\circ}C$및 3$0^{\circ}C$에서는 1 시간까지 증가되었다가 회복되는 경향을 나타내었다. 신장에서의 SOD활성은 $25^{\circ}C$인 경우 대조구보다 높은 값을 유지하였다. 하지만, 30도에서는 4 시간째까지 증가하는 경향을 보였으나 이후 감소하는 경향을 보였으며, 저온인 1$0^{\circ}C$에서는 감소하였다. 간장에서의 CAT의 활성은 3$0^{\circ}C$인 경우 4시간까지 $25^{\circ}C$ 및 15$^{\circ}C$에서는 2 시간까지 증가하였다가 이후 낮아지는 경향을 보였다. 이상의 결과로 고ㆍ저 수온변화에 따른 스트레스가 장기화될 경우 어체의 건강상에 문제점의 발생하여 대량 폐사 및 질병발생의 야기될 것으로 사료된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.150-155
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• 2019

Cavitation refers to a phenomenon in which empty spaces occur in a fluid due to changes in pressure and a velocity. When a liquid moves at a high speed, the pressure drops below the vapor pressure, and vapor bubbles are generated in the liquid. This study used CFD to analyze the flow of fluid machinery used in marine and offshore plants. The goals are to ensure the validity of the analysis method for marine propellers in an open water test, to increase the forward ratio, and to use FLUENT to understand the flow pattern due to cavitation. A three-dimensional analysis was performed and compared with experimental data from MOERI. The efficiency was highest at advance ratios of 0.7 - 0.8. Thrust was generated due to the difference between the pressure surface and the suction surface, and it was estimated that bubbles would be generated in the vicinity of the back side surface rather than the face side of the propeller, resulting in more cavitation. The cavitation decreased sharply as the advance ratio increased. The thrust and torque coefficients were comparable to those of the MOERI experimental data except at the advance ratio of 1, which showed a difference of less than 5%. Therefore, it was confirmed that CFD can evaluate an open water propeller test.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.1
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• pp.79-94
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• 2022

The demand for tunnel construction is increasing as part of underground space development due to urban saturation. The shield TBM method minimizes vibration and noise and minimizes ground deformation that occurs simultaneously with excavation, and shield TBM is generally applied to tunnel construction in urban areas. The importance of urban ground settlement prediction is increasing day by day, and in the case of shield TBM construction, ground deformation is minimized, but ground settlement due to tunnel excavation inevitably occurs. Therefore, in this study, the correlation between shield TBM, which is highly applicable to urban areas, and ground settlement is analyzed to suggest the shield TBM construction factors that have a major effect on ground settlement. Correlation analysis was performed between the shield TBM construction data and ground settlement measurement data collected at the actual site, and the degree of correlation was expressed as a correlation coefficient "r". As a result, the main construction factors of shield TBM affecting ground settlement were thrust force, torque, chamber pressure, backfill pressure and muck discharge. Based on the results of this study, it is expected to contribute to the presentation of judgment criteria for major construction data so that the ground settlement can be predicted and controlled in advance when operating the shield TBM in the future.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.11 no.2
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• pp.169-178
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• 2008

Purpose: The purpose of this study was to determine the efficacy of early low-dose iron supplementation in term breast-fed infants. Methods: Eighty-seven healthy term infants were divided into 3 groups: A, formula-fed; B, breast-fed only; S, breast-fed with iron supplementation (5 mg/day from 2 months of age). We measured ferritin, iron, total iron binding capacity (TIBC), transferrin saturation rate (TFSAT), hemoglobin (Hb), hematocrit (Hct), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and red cell distribution width (RDW) at birth, 6 months of age, and 12 months of age. Results: 1) At 6 months of age, ferritin, iron, TFSAT, and Hb in Group B were the lowest among the 3 groups, whereas TIBC and RDW were the highest. The incidences of iron deficiency (ID) and iron deficiency anemia (IDA) in Group B were 33% and 30%, respectively, significantly higher than those seen in Groups A (5% and 8%, respectively) and S (7% and 5%, respectively). 2) At 12 months of age, ferritin, TFSAT, Hb, MCV, and MCH in Group B were the lowest among the 3 groups, whereas TIBC and RDW were the highest. Iron and Hct did not differ among the 3 groups. The incidences of ID and IDA in Group B were 64% and 50%, respectively, again significantly higher than those seen in Groups A (4% and 3%, respectively) and S (9% and 7%, respectively). Conclusion: The prevalences of ID and IDA were higher in breast-fed infants than in formula-fed infants, even at 6 months of age. Early and low-dose iron supplementation in breast-fed infants improved iron status and lowered the incidence of iron deficiency anemia in early infancy.

• Korean Journal of Food Science and Technology
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• v.10 no.2
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• pp.112-118
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• 1978

Four domestic frying oils (soybean, corn, rapeseed and rice bran oil) were studied on their changing properties according to thermal oxidation by means of chemical analysis of their compositions and measurements of various physical and chemical properties. The content of linoleic acid which is an essential unsaturated fatty acid and the total amount of unsaturated fatty acids were highest in soybean oil (53.2% and 80.3% respectively) among the unheated frying oils and the degree of its thermal degradation was lowest during the continuous heating period for 48 hours at $180^{\circ}C$. However in general, the contents of unsaturated fatty acids were sharply decreased by thermal oxidation whereas the saturated fatty acid contents ranging 10-17% were not changed considerably, which largely agreed with the results of iodine value measurements. The free acid and peroxide values were also lowest in soybean oil (0.09 and 5.6 respectively) among the unheated oils whereas an anomalously high free acid value was observed in rapeseed oil (54.8) which was packed in unleveled glass bottles. Such a high value is probably ascribed to the photo-catalyzed oxidation during storage. The viscosity measurements have shown similar values before heating, but after thermal oxidation for 32 hours the rapeseed and rice bran oils became too thick to measure viscosity by capillary flow method with heavy darkening in color.

• Journal of Chest Surgery
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• v.31 no.8
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• pp.749-755
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• 1998

Background: Twelve patients with acyanotic tetralogy of Fallot(TOF), characterized by the combination of a malaligned ventricular septal defect(VSD) and infundibular pulmonic stenosis with the clinical finding of acyanosis at rest, underwent surgical correction between January 1988 and July 1997. Materials and methods: 9.92% of patients with the diagnosis of TOF were acyanotic TOF in the same period. Ages ranged from 12 to 42 months(mean 25.2 months). 2D-echocardiographic studies, cardiac catheterization, and angiocardiograms were performed in all patients before operation. The preoperative mean systemic arterial oxygen saturation was 93.5%. According to the 2D-echocardiographic analysis, there was Lt-to-Rt shunt through VSD in 4 patients, bidirectional shunt in 2 patients, and no shunt in 6 patients. Results: The preoperative mean right ventricle to pulmonary artery(RV-PA) pressure gradients were 52.3 mmHg on 2D- echocardiogram and 48.4 mmHg on cardiac catheterization. The repair of ventricular septal defect was performed through a right atrial approach and the hypertrophic infundibular muscle bundles were resected by the transatrial and transpulmonary approach. Six patients(50%) received a transannular patch. The mean cardiopulmonary bypass time was 135.0 minutes, and the aortic crossclamp time was 87.8 minutes. Postoperative complications included bleeding necessitating reentry in one and chylothorax in one. No patient died after operation and there were no late deaths. Postoperative 2D-echocardiograms revealed tiny patch dehiscence in 5 cases and a moderate RV-PA pressure gradients(mean 15.3 mmHg). All patients were in New York Heart Association functional class 1 after operation. Conclusions: acyanotic TOF is the uncommon form of TOF, and acyanotic TOF can be repaired with a good outcome.