• Korean Journal of Applied Biomechanics
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• v.24 no.3
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• pp.229-238
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• 2014

This study comparatively analyzed the speed and segment coordination characteristics of Taekwondo hand techniques, while different attention focusing strategies were utilized. Ten elite Taekwondo poomsae athletes participated, and three different strategies (no focus, target focus, body focus) were utilized in random order. The hand velocity and upper body segment coordination characteristics were analyzed, with the following results. First, the maximum magnitudes of the hand velocity differed between the focus conditions for the Araenaereomakgi and Momtongjireugi techniques. Second, the angular velocity and kinetic energy transfer patterns of the segments differed between the focus conditions, and in the case of the body focus condition, the movement was more correct according to the theory. Third, the shoulder and elbow joint coordination patterns differed between the focus conditions, with more efficient movement shown with the body focus condition. In conclusion, we confirmed the potential of effectively using an attention focusing strategy in a taekwondo teaching situation. However, the effect on the movement coordination and results of the movement could be changed by a difference in the cue provided or the type of the task. In addition, depending on the task, the attention focusing strategy could affect the efficiency of the movement. Therefore, coaches and masters of Taekwondo will have to constitute determine the appropriate attention focusing cues based on the task.

• Journal of Welding and Joining
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• v.19 no.3
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• pp.311-316
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• 2001

This paper presents that the affecting factors to the solderability and initial reliability. It is the factor that the coefficient of thermal expansion between package and PCB(Printed Circuit Board), the quantity of solder paste and reflow condition, and Au thickness of the solder ball pad on polyimide tape. As the reflow soldering condition for 48 ${\mu}BGA$ is changed, it is estimated that the quantity of Au diffusion at eutectic Sn-Pb solder surface and initial bonding strength of eutectic Sn-Pb solder and lead free solder. It is the result that quantitative measurement of Au diffusion quantity is difficult, but the shear strength of eutectic Sn-Pb solder joint is 842 mN at first reflow and increases 879 mN at third reflow. The major failure mode in solder is judged solder fracture. So, Au diffusion quantity is more affected by reflow temperature than by the reflow times.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.2
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• pp.311-316
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• 2008

Powder type Ag system insert metals were manufactured by ball milling process. The variables of milling process were constant except the milling time. The milling times were selected for 24, 48 and 72 hours. The insert metals made by milling process were evaluated by performing scanning electron microscope, DSC(differential scanning calorimetry) analyses, spreading test and further in terms of wettability test. The selected insert metals that have the good characteristics compared to commercial insert metals were applied to make the brazed joints. The characterizations of those brazed joints were also conducted by microstructural observations. The results indicated that milling time of 48 hours for making powder type insert metals was the best condition showing the good spreadibility, low wetting angle. The brazed joints that applied the 48 hours milled insert metal were very sound condition indicating the stable microstructure in spite of containing small amount of porosity and the microhardness value of the joint was about 138VHN.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.4
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• pp.2021-2026
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• 2013

In this study, the effect on the welding angle distortion was reviewed by carrying out a thermal elastic-plastic analysis while changing the cooling condition(width, length, and distance from weld torch to cooling torch) the back of the welding zone for the butt weld joint. The review results revealed that maximum 57% of reduction in the angle distortion was achieved when the distance between weld torch and cooling tip of 25mm, cooling length of 80mm, and cooling width of 30mm were maintained.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.7
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• pp.21-27
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• 2010

The effect of COG bonding parameters, especially the bonding temperature, on the bonding quality and reliability was investigated in this paper. We measured the bubble area formed in the ACF resin during the bonding process and tried to investigate the relationship between bubble area and bonding peel strength. 85/85 test which exposes a sample to a 85% humidity and $85^{\circ}C$ temperature condition was also carried out. The bubble area was dramatically increased under ~$10^{\circ}C$ lower than recommended bonding temperature. The bubble area formed at the edge of IC chip was larger than the other parts of IC chip. But the peel strength was not associated with the bubble area. High temperature and humid condition made the bubble area larger, but we could not find clear trend of change in the peel strength.

• Korean Journal of Acupuncture
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• v.30 no.3
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• pp.171-177
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• 2013

Objectives : The purpose of this study is to investigate the mechanism of Cosmetic Acupuncture through reinterpretation of anatomy and physiology. Methods : The causes of wrinkle increases and rapid aging of facial skin were studied and the theoretical system of Cosmetic Acupuncture treatment was analyzed through anatomy and physiology reinterpretation. Results and Conclusions : An increase in wrinkles and rapid aging of facial skin is caused by xerosis. Skin condition represents the condition of subcutaneous muscle. The reason why skin becomes easily dry is the heat produced by craniofacial part. Craniofacial part always generates lot of physiological fever because of the muscles. This physiological fever is produced from the muscles that are responsible for maintaining skull suture, controlling the movement of temporomandibular joint, maintaining head and neck posture. Controlling this fever is the crux of Cosmetic Acupuncture mechanism. These muscles correspond to Foot Taeyang meridian-muscle, Foot Soyang meridian-muscle and Foot Yangmyung meridian-muscle. Cosmetic Acupuncture is effective for preventing facial skin from aging and wrinkle increase by mechanical stimulus on facial muscles, and for controlling craniofacial part meridian-muscle system producing the heat.

• Journal of Welding and Joining
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• v.29 no.5
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• pp.82-89
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• 2011

The effect of welding condition on tensile properties of KS5J32 Al Alloy was investigated under various welding conditions. The 1.6 mm thick KS5J32 alloy sheets were joined by friction stir welding (FSW) technique with butt joint. The tool rotation speeds were 1000, 1250 and 1500 rpm, and the welding speeds were varied within the range from 100 to 600 mm/min. Voids mainly occurred at the advancing side of the tool probe, when the tool rotation speed was low, due to insufficient materials flow. When the weld pitch exceeded 0.4 mm/rev, voids were observed under all welding conditions and the area of voids increased with increasing weld pitch. For void-free specimens, fracture always occurred at base materials. However voids affected the location of fractures, base metal or welded zone, when the voids existed within the welds.

• Journal of Welding and Joining
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• v.22 no.1
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• pp.77-82
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• 2004

The effect of bonding condition on tensile properties of joints diffusion bonded spheroidal graphite cast iron, FCD60 to Cr-Mo steel, SCM 440 was investigated. Diffusion bonding was performed with various temperatures, holding times, pressures and atmospheres. All tensile specimens were fractured at the bonding interface. The tensile strength and elongation was increased with increasing bonding temperature. Especially, tensile strength of joints bonded at 1123K was higher than that of a raw material, FCD60, and tensile strength of joints bonded at 1173K was equal to that of a raw material, SCM440, but elongation of all joints was lower than those of raw materials. There was little the effect of holding time on the tensile properties. In comparison with bonding atmosphere, the difference of tensile strength was not observed, but elongation of joint bonded at vacuum(6.7mPa and 67mPa) was higher than that of Ar gas. Higher the degee of vacuum, elongation increased. Tensile properties of diffusion bonds depended on microstructures of cast iron at the interface and void ratio. Microstructures of cast iron at interface changed with temperature, because decarburizing and interdiffusion at the interface occurs and transformation of austenite-1 ferrite + graphite occurs on the cooling process. The void ratio decreased with increasing temperature, especially, effected on the elongation.

• Journal of Welding and Joining
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• v.29 no.6
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• pp.49-55
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• 2011

With the development of pre-painted steel sheets for automotive body application, a new joining method is required such as hybrid joining with combination of adhesive bonding and mechanical joining. The objective of this study is to investigate the effect of pre- and post-baking of adhesive bonding on failure mode and strength of hybrid joining of automotive steel sheets. Experiments show that the hybrid joining exhibits better bonding strength and displacement than conventional adhesive joining and mechanical fastening each. Comparison of pre- and post-baked hybrid joining results suggested that baking at $160^{\circ}C$ after mechanical joining was found to have higher joining properties than pre-baking condition. The prebaking condition changed its fracture mode from interfacial to button fracture. The changes in fracture mode with post-baking of hybrid joining was attributed to variation in neck thickness and undercut of joint.

• Journal of Yeungnam Medical Science
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• v.36 no.2
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• pp.92-98
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• 2019

Forefoot disorders are often seen in clinical practice. Forefoot deformity and pain can deteriorate gait function and decrease quality of life. This review presents common forefoot disorders and conservative treatment using an insole or orthosis. Metatarsalgia is a painful foot condition affecting the metatarsal (MT) region of the foot. A MT pad, MT bar, or forefoot cushion can be used to alleviate MT pain. Hallux valgus is a deformity characterized by medial deviation of the first MT and lateral deviation of the hallux. A toe spreader, valgus splint, and bunion shield are commonly applied to patients with hallux valgus. Hallux limitus and hallux rigidus refer to painful limitations of dorsiflexion of the first metatarsophalangeal joint. A kinetic wedge foot orthosis or rocker sole can help relieve symptoms from hallux limitus or rigidus. Hammer, claw, and mallet toes are sagittal plane deformities of the lesser toes. Toe sleeve or padding can be applied over high-pressure areas in the proximal or distal interphalangeal joints or under the MT heads. An MT off-loading insole can also be used to alleviate symptoms following lesser toe deformities. Morton's neuroma is a benign neuroma of an intermetatarsal plantar nerve that leads to a painful condition affecting the MT area. The MT bar, the plantar pad, or a more cushioned insole would be useful. In addition, patients with any of the above various forefoot disorders should avoid tight-fitting or high-heeled shoes. Applying an insole or orthosis and wearing proper shoes can be beneficial for managing forefoot disorders.