• International Journal of Aeronautical and Space Sciences
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• v.16 no.4
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• pp.602-613
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• 2015

As one of the mission payloads to be verified through the cube satellite mission of Cube Laboratory for Space Technology Experimental Project (STEP Cube Lab), we developed a hinge driving separation nut-type holding and releasing mechanism. The mechanism offers advantages, such as a large holding capacity and negligible induced shock, although its activation principle is based on a nylon cable cutting mechanism triggered by a nichrome burn wire generally used for cube satellite applications for the purpose of holding and releasing onboard appendages owing to its simplicity and low cost. The basic characteristics of the mechanism have been measured through a release function test, static load test under qualification temperature limits, and shock measurement test. In addition, the structural safety and operational functionality of the mechanism module under launch and on-orbit environments have been successfully demonstrated through a vibration test and thermal vacuum test.

• Journal of Korea Foundry Society
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• v.25 no.6
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• pp.249-253
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• 2005

The present study focuses on 7075 aluminum wrought alloy to investigate the potential industrial applications of thixoextrusion process. The microstructural evolution of 7075 aluminum wrought alloy for thixoextrusion has been investigated as a function of isothermal holding temperature and time in the partially remelted semisolid state. The results showed that the liquid fraction increased with increasing isothermal holding temperature and time while the average grain size was inversely proportional to isothermal holding temperature and time up to 5min. However, there was no big change of liquid fraction and average grain size with respect to isothermal holding temperature and time. The important fact that the liquid fraction and average grain size were almost uniform after 5 min holding time is considered very useful for thixoextrusion in terms of process control.

• Korean journal of food and cookery science
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• v.20 no.1
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• pp.34-41
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• 2004

The retention rate of riboflavin in two cooked vegetable salads (spinach salad and sesame leaf salad) were examined at every cooking stage, holding temperature and holding time, with various cooking methods, and a better food preparation method developed. The riboflavin contents of the samples were analyzed by HPLC, with fluoresence detection. The changes in the pH and water contents of the samples were measured during the holding stage at various temperatures and times. There were significant differences in the riboflavin contents during the various preparation and cooking processes, such as trimming, washing, boiling and parching etc. The retention rates of the riboflavin with the various holding methods and cooking temperature were also significantly different. The boiling process caused large losses of riboflavin: in the cases of spinach salad and sesame leaf salad these were 78％ and 52％ respectively. The pH and water contents showed faster change during 0-6 hours than during 6-12 hours.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.3
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• pp.541-544
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• 1992

Duck eggs from Indigenous (desi), Khaki Campbell and Crossbred (Indian Runner $\times$ Khaki Campbell, $F_1$) were incubated to investigate fertility, hatchability and other related traits. The fertility was highest in crossbred followed by Khaki Campbell and Indigenous ducks respectively. The embryonic mortality was highest in Khaki Campbell followed by Indigenous and crossbred respectively. The embryonic mortality was higher in eggs of 7 days pre-incubation holding period and lower in eggs of 3 days pre-incubation holding period. A significant positive correlation was found between temperature and embryonic mortality as well as relative humidity and embryonic mortality. The hatchability on fertile eggs was highest in crossbred ducks and almost similar in both Khaki Campbell and Indigenous ducks. The hatchability was higher in eggs stored for 3 days in comparison with that of 7 days pre-incubation holding period. A negative correlation was found between temperature and hatchability as well as humidity and hatchability. The normal ducklings hatched out from the eggs of Khaki Campbell ducks was highest followed by Indigenous and crossbred respectively. There was a negative correlation between temperature and normal ducklings hatched as well as relative humidity and normal ducklings hatched. The preincubation holding temperature and relative humidity had positive correlation with dead-in-shell.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.199-203
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• 1995

The technology of Semi-Solid Forging (SSF) has been actively developed to fabricate near-net- shape products using light and hardly formable materials, the SSF process is composed of slug heating, forming, compression holding and ejecting step. After forming step in SSF, the slug is compressed during a certain holding time in order to be completely filled in the die cavity and be accelerated in solidification rate. The compression holding time that can affect mechanical properties and shape of products is important to make decision, where it is necessary to find overall hert transfer coefficeient properly which has large effect on heat transfer between slug and die. This paper presents the procedure to predict compression holding time of octaining the final shaped part with information of temperature and solid fraction for a cylindrical slug at compression hoiding step in closed-die compression process using heat transfer analysis considering latent heat by means of finite element method. The influence of the predicted compression hoiding time on mechanical properties of products is finally investigated by experiment.

• Journal of Korean Institute of Industrial Engineers
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• v.30 no.2
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• pp.76-83
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• 2004

This study aimed to empirically investigate perceived discomfort depending upon external load, upper limb postures and their holding time. Discomfort was obtained through an experiment, in which external load, wrist flexion/extension, elbow flexion, shoulder flexion and adduction/abduction were used as experimental variables. The subjects were instructed to hold given postures for 60s and to rate their subjective discomfort scores at 5s, 20s, 40s and 60s by using the free modulus method of magnitude estimation. The results showed that while only external load and elbow flexion were statistically significant at the holding time of 5s at ${\alpha}=0.05$ or 0.10, external load and upper limb postures excluding shoulder adduction/abduction significantly affected discomfort ratings at 20s, 40s and 60s at ${\alpha}=0.01$ or 0.05. Discomfort scores were also significantly different between four posture holding times at ${\alpha}=0.01$. The effects of external load and holding time were much larger than those of upper limb postures. Based on the results of this study, it is recommended that external load and holding time as well as working postures betaken into consideration to precisely quantify postural load in industry.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.1
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• pp.83-87
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• 2003

The study evaluates the enzymatic dry matter (DM) degradability and water holding capacity of leaf and stem fractions of orchardgrass (Dactylis glomerata L.) at different growth stages with or without the presence of surfactant Tween 80. While Tween 80 significantly (p<0.05) increased water and enzyme holding capacities in the leaf blades fraction, less was observed in the fraction of leaf sheath and stem of orchardgrass. The enzyme holding capacity in the leaves was also altered more than that for water holding capacity. This resulted in the increased rate and extent of enzymatic hydrolysis of the leaf blade fractions at two growth stages, whereas little was with leaf sheath and stem fractions. It was also observed that at 0.005% concentrations of Tween 80 the enzymatic DM degradability of young leaf blades was higher (p<0.05) by 20-30% compared to that of the control, as well as for water and enzyme holding capacity. For matured leaf blades the DM degradability were increased with over 0.01% concentrations of the surfactant, but the increase was less than leaf blades of young orchardgrass. This result suggests the possibility of using the surfactant Tween 80 to improve forage digestibility in the rumen.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.43-46
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• 1997

The interfacial bond strength and microstructural analysis of pre-heat treated porcelain-fused-metal (PFM) were investigated using a mechanical three-point bending tester and scanning electron microscope(SEM). Four kinds of heat treated samples were prepared as follows; A: heating $1200^{\circ}F\rightarrow1600^{\circ}F$, holding 1min, reheating $\rightarrow1850^{\circ}F$, hold 3min under vacuum, B: heating $1200^{\circ}F\rightarrow1600^{\circ}F$ holding 1min, reheating $\rightarrow1850^{\circ}F$ under vacuum condition, C: heating $1200^{\circ}F\rightarrow1600^{\circ}F$, holding 1min, reheating $\rightarrow1850^{\circ}F$, holding 3min in the air, repeat same heat treatment process under vacuum condition, D: heating $1200^{\circ}F\rightarrow1600^{\circ}F$, holding 1min, reheating $\rightarrow1850^{\circ}F$, holding 1min in the air. The three-point bending test results shows that the interfacial bond strength of specimen B and C were higher than that of A and B. The SEM study reveals that Specimen C shows the highest surface density.

• Journal of Technologic Dentistry
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• v.19 no.1
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• pp.37-42
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• 1997

The interfacial bond strengh and microstructural analysis of pre-heat treated porcelain-fusedmetal(PFM) were investigated using a mechanical three-point bending tester and scanning electron microscope(SEM). Four kinds of heat treated samples were prepared as follows ; A: Heating $1200^{\circ}F{\to}1600^{\circ}F$, holding 1min, reheating ${\to}1850^{\circ}F$, hold 3min under vacuum, B: heating $1200^{\circ}F{\to}1600^{\circ}F$, holding 1min, reheating${\to}1850^{\circ}F$ under vacuum conditon, C: heating $1200^{\circ}F{\to}1600^{\circ}F$, holding 1min, reheating${\to}1850^{\circ}F$, holding 3min in the air, repeat same heat treatment process under vacuum condition, D: heating $1200^{\circ}F{\to}1600^{\circ}F$, holding 1min, reheating${\to}1850^{\circ}F$, holding 1min in the air. The three-point bening test result shows that the interfacial bond strength of specimen B and C were higher than that of A and D. The SEM study indicate that Specimen C shows the highest surface density.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.42-47
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• 2004

Air-fuel mixing and flame-holding are two important factors that have to be considered in the design of an injection system. Different injection strategies have been proposed with particular concern for rapid air-fuel mixing and flame-holding. Two representative injection techniques can be applied in a supersonic combustor. One of the simplest approaches is a transverse(normal) injection. The cavity flame holder, an integrated fuel injection/flame-holding approach, has been proposed as a new concept for flame holding and air-fuel mixing in a supersonic combustor. This paper describes numerical efforts to characterize the flame-holding and air-fuel mixing process of a model scramjet engine combustor, where hydrogen is injected into a supersonic cross flow and a cavity. The combustion phenomena in a model scramjet engine, which has been experimentally studied at University of Queensland and Australian National University using a free-piston shock tunnel, were observed around the separation region of the transverse injector upstream and the inside cavity. The results show that this flow separation generates recirculation regions which increase air-fuel mixing. Self-ignition occurs in the separation-freestream and cavity-fteestream interfaces.