• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2003년도 춘계학술대회 논문집
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• pp.43-47
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• 2003

This paper presents the optimum design of cylindrical shell under external pressure loading. Two kinds of material, AI7075-T6, Ti-6AI-4V, are considered. For each material, the design variable is a thickness of the unstiffened parallel middle body shell, and the state variable, constraint, is hoop stress and the object function is total weight of the cylindrical shell. Optimization is performed by conventional FE Program, ANSYS. In addition, buckling analysis is performed for the middle body of the cylindrical shell. Finally, we calculates the payload of the cylindrical shell to keep neutral buoyancy with optimized thickness in deep-sea applications.

• 한국수산과학회지
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• 제47권5호
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• pp.577-581
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• 2014

The aim of this study was to investigate the effect of diet extruder conditions, such as feed-loading rate and screw speed, on growth performance and biochemical responses in olive flounder Paralichthys olivaceus. Over 8 wks, we used four identical diets (triplicated per treatment) with differing ratios of feed-loading rate (kg/h):screw speed (rpm/min) in a laboratory-scaled twin-screw extruder of 50:640, 80:640, 120:640, and 80:400, designated as EP1, EP2, EP3, and EP4, respectively. Screw speed impacted the buoyancy of experimental diets. Diets produced at a screw speed of 640 rpm/min floated for > 24 hrs, whereas those produced at a speed of 400 rpm/min sank between 10 s and 5 min. Fish that were fed EP1 and EP4 diets grew significantly faster than those fed EP2 and EP3 diets. Fish fed EP1 diets ate and gained weight most efficiently among treatments, a result that is likely to be related to feed-loading rate, i.e., ingredients extruded at a low feed-loading rate may have more time to cook in the pre-conditioner of the extruder. A cooked diet may be easier to digest in fish. Fish fed EP4 diets also showed significant weight gain, as compared to those fed EP2 and EP3 diets. However, we found no differences among treatments in proximate compositions of dorsal muscle, liver, and viscera of fish. Our results suggest that extruder conditions, may influence feed quality, impacting feed efficiency and growth of fish.

• 농약과학회지
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• 제16권4호
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• pp.391-394
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• 2012

Chlorpyrifos 유제 살포액 조제 시 작업자의 손 노출량 측정하였으며, 위해성 평가를 실시하였다. 분석기기상의 검출한계는 0.25 ng, 정량한계는 1 ng로 설정하였고, 표준 검량선의 직선성과 분석재현성은 우수하였다. 장갑의 회수율은 72.3-103.4% 이었다. 살포액 조제 시 평균 손 노출은 3.9 mg이었으며, 조제 약량 대비 0.004%이었다. 위해성평가를 하기 위하여 한국 평균 남자 체중, 농작업자노출허용량(AOEL, acceptable operator exposure level) 손 노출량을 비교하였다. 또한 하루 조제 횟수는 8회로 가정하였고, 가장 많이 노출되는 최악의 경우를 확인하기 위하여 30 반복 손 노출량의 75 percentile에 해당하는 노출량(4.6 mg)을 이용하여 위해성 평가 결과 위해성이 낮은 것으로 판단되었으나, 30반복 각각의 위해성 평가 결과 2회는 노출량보다 허용량보다 많아서 위해성이 예상되었다.

• 한국잠사곤충학회지
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• 제40권1호
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• pp.38-42
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• 1998

This study designed to investigate the blood glusose lowering effect of sericultural products using allozan-induced byperglycemic mice. The administration of sericultural products did not affect body weight between normal mice and alloxan induced hyperglycemic mice. High blood glucose level in alloxan-induced mice group was maintained, during all the experimental period. In the 2-3 weeks, a significant decrease in the blood glucose level was observed in the group treated with sericultural products. Up to 5 weeks, blood glucose level of those group was maintained. Sericultural products treatment group have an activity for glucose tolerance test. Sericultural products showed the blood glucose lowering acivity for loading maltose and sucrose.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 춘계학술대회 논문집
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• pp.295-299
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• 2007

Biped robot requires that an energy source and a control part should be installed on the body to realize active system. So, we choose the DC motor having high torque in compact size in this study. In the DC motor serve system, we choose power amplifier with analog configuration, developed the module combined the controller and the driver. We applied this module to robot actuator and studied the response characteristics in an action and a return. Main controller with serve system, loading PIC micro controller, can be load on the robot with light weight.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.155-161
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• 2007

A bogie frame is typical safty part of railway vehicle. Main performance of a bogie frame is to support a car body and passenger weight and transfer traction and braking force. This paper is to evaluate the static strength and fatigue strength for the end trailer bogie with UIC 615-4 code. Therefore stress analysis of the end trailer bogie frame has been performed for various loading condition according to the UIC 615-4 code and haigh diagram is used for evaluation of fatigue strength. By the results of these analysis, static and fatigue strength of the end trailer bogie is satisfied with a applied criterion.

• 한국운동역학회지
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• 제26권2호
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• pp.143-151
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• 2016

Objective: The purpose of this study was to investigate the effect of fatigue induction on ground reaction force (GRF) components, postural stability, and vertical jump performance in Taekwondo athletes. Method: Ten Taekwondo athletes (5 men, 5 women; mean age, $22.30{\pm}2.62years$; mean height, $174.21{\pm}9.20cm$; mean body weight, $67.28{\pm}12.56kg$) participated in this study. Fatigue was induced by a short period of strenuous exercise performed on a motorized treadmill. The analyzed variables included vertical jump performance, static stability (mediolateral [ML], center of pressure [COP], anteroposterior [AP] COP, ${\Delta}COPx$, ${\Delta}COPy$, and COP area), postural stability index values (ML stability index [MLSI], AP stability index [APSI], vertical stability index [VSI], dynamic postural stability index [DPSI]), and GRF components (ML force, AP force, peak vertical force [PVF], and loading rate). To analyze the variables measured in this study, PASW version 22.0 was used to calculate the mean and standard deviation, while a paired t-test was used to evaluate the pre- versus post-fatigue results. Pearson's correlation coefficients among variables were also analyzed. The statistical significance level was set at ${\alpha}$ = .05. Results: Vertical jump performance decreased significantly after the induction of fatigue, while AP COP, ${\Delta}COPx$, COP area, APSI, VSI, and DPSI increased significantly. PVF and loading rate increased significantly after the induction of fatigue, while the postural stability variables (AP COP, ${\Delta}COPy$, COP area, APSI, VSI, DPSI) were similarly correlated with GRF components (PVF, loading rate) after fatigue was achieved (r = .600, $R^2$ = 37%). Conclusion: These results suggest that the induction of fatigue can decrease postural stability and exercise performance of Taekwondo athletes during training and competition sessions.

• 한국운동역학회지
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• 제24권1호
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• pp.43-50
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• 2014

The purpose of this study was to analyze of the GRF (ground reaction force) parameters according to the change of positions and weights of bag during downward stairs between dominant and non-dominant in upper & lower limbs. To perform this study, participants were selected 9 healthy women (age: $21.40{\pm}0.94yrs$, height: $166.50{\pm}2.68cm$, body mass: $57.00{\pm}3.61kg$, BMI: $20.53{\pm}1.03kg/m^2$), divided into 2 carrying bag positions (dominant arm/R, non-dominant arm/L) and walked with 3 type of bag weights (0, 3, 5 kg) respectively. One force-plate was used to collect GRF (AMTI OR6-7) data at a sample rate of 1000 Hz. The variables analyzed were consisted of the medial-lateral GRF (Fx), anterior-posterior GRF (Fy), vertical GRF (Fz), impact loading rate and center of pressure (COPx, COPy, COP area, COPy posterior peak time) during downward stairs. 1) The Fx, Fy, Fz, COPx, and COP area of GRF were not statistically significant between dominant leg and non-dominant leg, but non-dominant leg, that is, showed the higher COPy, and showed higher impact loading rate than that dominant leg during downward stairs. 2) In bag wearing to non-dominant arm, Fx, Fz, COPx, COPy, impact loading rate and COP area showed increase tendency according to increase of bag weights. Also, against bag wearing to dominant arm, non-dominant showed different mechanism according to increase of bag weights. The Ground Reaction Force parameters showed different characteristics according to the positions and weights of bag during downward stairs between dominant and non-dominant arm.

• 한국운동역학회지
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• 제27권1호
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• pp.1-7
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• 2017

Objective: The purpose of this study was to analyze the relationship between ground reaction force (GRF) and attack time according to the position of hand segments during counter attack in Kendo. Method: The participants consisted of 10 kendo athletes (mean age: $21.50{\pm}1.95yr$, mean height: $175.58{\pm}5.02cm$, mean body weight: $70.96{\pm}9.47kg$) who performed standard head strikes (A) and counter attack with a preferred hand position of +10 cm (B), 0 cm (C), and -10 cm (D). One force-plate (AMTI-OR-7., USA) was used to collect GRF data at a sample rate of 1,000 Hz. The variables analyzed were the attack time, medial-lateral GRF, anterior-posterior GRF (AP GRF), peak vertical force (PVF), and loading rate. Results: The total attack time was shorter in types A and C than in types C and D. The AP GRF, PVF, and loading rate had significantly higher forces in types C and D than in types A and C. The attack time (bilateral and unilateral leg support and total) was positively correlated with the GRF variables (vertical GRF and loading rate) during the counter attack in Kendo (r = 0.779 [$R^2=0.607$], p < 0.001). Conclusion: The positions of the hand segments can be changed by various conditions of the opponent in Kendo competitions; however, the position preferred by an individual can promote the successful ratio of the counter attack.

• Animal Bioscience
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• 제34권10호
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• pp.1684-1694
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• 2021

Objective: This study investigated the association between feed efficiency, physicochemical properties, flavor precursors and biomolecules in the thigh meat of Korat (KR) chickens. Methods: The feed intake and body weight of individual male KR chickens were recorded from 1 to 10 weeks old to calculate the individual residual feed intake (RFI) of 75 birds. At 10 weeks of age, chickens with the 10 highest (HRFI) and lowest RFI (LRFI) were slaughtered to provide thigh meat samples. The physicochemical properties (ultimate pH, water holding capacity [WHC], drip loss) and flavor precursors (guanosine monophosphate, inosine monophosphate (IMP), adenosine monophosphate and inosine) were analyzed conventionally, and Fourier transform infrared spectroscopy was used to identify the composition of biomolecules (lipids, ester lipids, amide I, amide II, amide III, and carbohydrates) and the secondary structure of the proteins. A group t-test was used to determine significant differences between mean values and principal component analysis to classify thigh meat samples into LRFI and HRFI KR chickens. Results: The physicochemical properties of thigh meat samples from LRFI and HRFI KR chickens were not significantly different but the IMP content, ratios of lipid, lipid ester, protein (amide I, amide II) were significantly different (p<0.05). The correlation loading results showed that the LRFI group was correlated with high ratios of lipids, lipid esters, collagen content (amide III) and beta sheet protein (rg loading >0.5) while the HRFI group was positively correlated with protein (amide I, amide II), alpha helix protein, IMP content, carbohydrate, ultimate pH and WHC (rg loading >0.5). Conclusion: The thigh meat from chickens with different RFI differed in physiochemical properties affecting meat texture, and in the contents of flavor precursors and biomolecules affecting the nutritional value of meat. This information can help animal breeders to make genetic improvements by taking more account of traits related to RFI.