• Korean Journal of Applied Biomechanics
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• v.13 no.1
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• pp.63-72
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• 2003

This study is examine and analysis of the most flying and run distance during swing three times with six balls between two amateurs and pro-golfers in golf field in Sungnam airport. During down swing, kinetics variances are velocity of club-head and balls, vertical angular velocity. this scientic data present amateur golfers with recognition of long flying distances for golf balls. Through this study, the conclusions are as follows. 1. Before impact the balls, The club-head velocity of amateur golfers and pro-golfers show 33.34 - 39.53m/s, 39.04 - 42.82m/s respectively during the down swing. But The club-head velocity, flight and Run distances comparative $K_1$ amateur golfer with the pro-golfer are similar. 2. After impact the balls, The balls velocity if amateur golfers show 53.04 - 61.57m/s, The pro-golfers show 62.32 - 63.4m/s respectively during the down swing. In case of $K_3$,$K_4$, After the impact balls velocity comparative The RA brand with other brand are similar, Flight and Run distance are difference. 3. After impact the balls, The balls velocity are difference to other brand but The long flight and Run distance arrange RA, BIG, TITL. 4. In the vertical flight angle of the ball after impact, amateur golfer showed 16.75 - $18.73^{\circ}$. The pro-golfer showed 15.03 - $16.04^{\circ}$. In the vertical flight angle of the balls ideal $12-13^{\circ}$, The long flight and Run distance approach In the vertical flight angle the balls $12-13^{\circ}$.

• Korean Journal of Applied Biomechanics
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• v.13 no.2
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• pp.101-114
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• 2003

The purpose of this study was to examine the major kinematicak variance to Increase the club head velocity during the driver swing two PGA prp-golfers utilizing 3-dimensional Image analyzing linear velocity of the club-head during the impact quantiatively. To achive these purpose, two high speed camera in 120 field/s and one high-speed camera in 500 field/s were used in this study. The program made by Younghoo Kwon(1944) was used to analysis the digitalization of reference point, digitalization of joint venter, synchronization, calculation of 3-Dimensional coordinate by DLT method, and smoothing. Through this study, the conclusions are as follow. 1. During the drivel swing, in the percentile of the total time, two pro-golfer showed 0.925, 0.929 second from adress to top-swing, 0.236, 0.929 second from top-swing to impact. 2. During the driver swing, in the displacement of the center of the body, two pro-golfer showed 45.3, 45.23% from adress, 44.3, 44.24% front impact. 3. In the velocity variance, The maximum club-head velocity two pro-golfer showed 43.36, 43.24m/s respectively the down swing. The ball velocity showed 63.12, 63.06m/s. 4. In the rotational angle of the shoulder joint. two pro-golfer showed $-13.5,-13.53^{\circ}$, during the back swing respectively. Two subject adressed opening status og upper body. 5. In the rotational angle of the right knee angle showed $156.3,154.7^{\circ}$ from the adress.

• Korean Journal of Applied Biomechanics
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• v.13 no.1
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• pp.155-171
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• 2003

The purpose of this study was to analyze the kinematic variables of over head kick(OHK) in soccer with three dimensional analysis technique and show the kinematic characteristics of it. The 7 subjects were university football player who have been playing football more than 7 years. The OHK was filmed on 16mm video camera(30frame/sec.) kinematic variables were temporal, postures, and COG(center of gravity). The mean values and the standard deviation for each variables were obtained and used as basic factors for examining characteristics of OHK. The results of this analysis were as follows : Temporal variables : The total time elapsed(TE) of OHK was $0.95{\sim}1.14sec$, the 1st phase was 0.35sec., 2nd phase was 0.46sec., and 3rd phase was 0.22sec.. Posture variables : When subjects performed OHK at the impact event, the ankle and knee angle of kicking foot were more extend than supporting foot. but the hip angle of supporting foot were more extend than kirking foot. Moving distance of the center of mass of the both foot. When subject performed OHK at the impact event, the range of distance on mediolateral direction aspect into right left shoulder line, anteroposterior direction aspect was $20.9{\pm}10.5cm$, vertical direction aspect was $92.3{\pm}19.9cm$. Angular velocity : the faster angular velocity of knee ankle on the kicking foot pew form jump position to landing position, the faster velocity of ball became. C. O. G. variables. When subject performed OHK at the impact event, upper part of the body was getting lower, lower part of the body was getting higher.

• Korean Journal of Applied Biomechanics
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• v.20 no.4
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• pp.447-455
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• 2010

The objective of this study was to analyze the difference in kinematic variables for successful and unsuccessful golf putting strokes. The study population included 8 male secondary school golf players who had played golf for over 3 years and whose handicap was 4 or lower. A hole was made on a 5-m-long artificial flat mat for practice, and an environment similar to that of a real green was created. The participants' motions were analyzed through 3D image analysis, and the difference in kinematic variables for successful and unsuccessful putting strokes in the same direction was determined. Data analysis revealed the following findings: The time spent for a segment of putting was the greatest for the backswing segment for both successful and unsuccessful strokes. During address and impact, the both changed to a larger extent. For successful putting strokes, the change in the elbow angle during the downswing was greater for the right elbow than for the left elbow. For both successful and unsuccessful putting strokes, the left shoulder angle increased during the segment from address to the turning point and decreased during the segment from the turning point to impact. In contrast, the right shoulder angle significantly differed between successful and unsuccessful putting strokes only during address. During successful and unsuccessful motions, the swing was executed with the moving displacement of the X-axis of the club head maintained almost constant along a straight light without back and forth movement. In the backswing segment, moving displacement of the Y- and Z-axes was greater in successful strokes than in unsuccessful strokes; however, this difference was very small for the Y-axis. The velocity of the club head for successful and unsuccessful motions significantly differed during address and at the turning point. The highest velocity of the ball was greater for successful than for unsuccessful putting strokes.

• Korean Journal of Applied Biomechanics
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• v.18 no.3
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• pp.43-80
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• 2008

The purpose of this research is to analysis the swing of driver used by professional golfers during on-season. In order to collect on-season driver swings of research objects, which are three KPGA(Korean Professional Golfer Association) professional golfers, measurements were carried out right after the last game of a season. The analysis range was set to down-swing point while analysis was conducted to after-impact, release point. As a result, systematic process between leading segments of the previous precise kinematic analysis research seems to turn up the same. However, there were different results compared to the preceding research. All three testers expressed adduction of left hand which could not be described with forming cocking angle, in consequence, adduction of left hand does not have a big effect on formation of cocking. Moreover, chest movement right before the impact; which was emphasized in previous research, the direction was not opposite but the same with the ball.

• Korean Journal of Applied Biomechanics
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• v.23 no.2
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• pp.117-123
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• 2013

The purpose of this study was to provide data to increase the success rate of penalty kicks through quantifying the shape of skilled kicks by performing a kinematic analysis on the change of movement during the kicking phase which the goalkeeper uses as a vital clue. Three high definition video cameras(GR-HD1KR, JVC, Japan) were used for the study and 18 reflective markers were attached to the body joints. Corners of the goal, difficult for goalkeepers to block, were set as aims and 1 m by 1.2 m targets were installed. Each subject had five sets of kicks at random, and the analysis was done on the movements that hit the target. Time, speed of the right lower limb's center of mass, joint angle, and angular velocity were chosen as factors and the results of the analysis showed statistical significance. The player taking a penalty kick should train to avoid leaning one's body towards the kicking direction and change the angle of the right foot right before the impact to decide the direction of the ball. The goalkeeper can increase the save success rate by studying the angle of the kicker's body and the right foot as well as the timing of the kick.

• Nuclear Engineering and Technology
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• v.50 no.6
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• pp.957-962
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• 2018

The gamma radiation shielding capability (GRSC) of two clay-materials (Ball clay and Kaolin)of Southwestern Nigeria ($7.49^{\circ}N$, $4.55^{\circ}E$) have been investigated by determine theoretically and experimentally the mass attenuation coefficient, ${\mu}/{\rho}(cm^2g^{-1})$ of the clay materials at photon energies of 609.31, 1120.29, 1173.20, 1238.11, 1332.50 and 1764.49 keV emitted from $^{214}Bi$ ore and $^{60}Co$ point source. The mass attenuation coefficients were theoretically evaluated using the elemental compositions of the clay-materials obtained by Particle-Induced X-ray Emission (PIXE) elemental analysis technique as input data for WinXCom software. While gamma ray transmission experiment using Hyper Pure Germanium (HPGe) spectrometer detector to experimentally determine the mass attenuation coefficients, ${\mu}/{\rho}(cm^2g^{-1})$ of the samples. The experimental results are in good agreement with the theoretical calculations of WinXCom software. Linear attenuation coefficient (${\mu}$), half value layer (HVL) and mean free path (MFP) were also evaluated using the obtained ${\mu}/{\rho}$ values for the investigated samples. The GRSC of the selected clay-materials have been compared with other studied shielding materials. The cognizance of various factors such as availability, thermo-chemical stability and water retaining ability by the clay-samples can be analyzed for efficacy of the material for their GRSC.

• The Journal of Korean Physical Therapy
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• v.28 no.1
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• pp.27-32
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• 2016

Purpose: The purpose of this study is to examine the effects of sensorimotor training on knee joint stability after anterior cruciate ligament reconstruction. Methods: The subjects were sixteen 16 adults who received anterior cruciate reconstruction by arthroscopy, and underwent sensorimotor training for which was to have them maintenanceain of a standing position with a step Balance ball on the affected side over 30 degrees knee flexion with 100% weight bearing for 15-20 seconds. Before the genuine experiment commenced, the Lysholm scale was had been used to assess functional disorders on the affected knee joint. KT-2000 Arthrometer measurement equipment was used to measure anterior displacement of tibia against to femur before and after the sensorimotor training. Results: There was significant relaxation on the affected side in tibia anterior displacement of the affected and sound sides on in supine position before the sensorimotor training. There was little significant difference in tibia anterior displacement of the affected knee joints on in the supine position before and after the sensorimotor training. The results also showed that there was a reduction in the difference of tibia anterior displacement of the affected knee joints on in the standing position. These results suggest that the effects of sensorimotor training on knee joint stability after anterior cruciate ligament reconstruction is to induce the change of tibia anterior displacement against femur and the variation of muscles activation. Conclusion: The sensorimotor training may contribute to the improvement of joint functional stability in people who are in post-operation state and with orthopedic musculoskelectal injuries.

• Journal of Chest Surgery
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• v.38 no.2 s.247
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• pp.175-179
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• 2005

The operative case of transmanubrial osteomuscular sparing approach for the tumor involving thoracic inlet is reported. A 69-year-old man visited the hospital due to right upper extremity weakness. Chest roentgenogram showed bronchiectasis, chronic pulmonary tuberculosis, and fungal ball in right upper lobe. On computed tomogram, tumor was located in epidural space of the 6th, the 7th cervical, and the 1st thoracic spine and extended to the apex of the right thorax. A neurosurgeon performed laminectomy and removed the tumor located in the spinal canal. A thoracic surgeon performed a transmanubrial osteomuscular sparing approach and removed the tumor involving thoracic inlet. The tumor was diagnosed as hemangiopericytoma. The patient recovered without complication.

• Journal of the Korean Vacuum Society
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• v.4 no.S2
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• pp.100-105
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• 1995

Nitrogen implantation process has been applied for improvement of wear resistance of Zircaloy-4 fuel cladding materials. Nitrogen was implanted at 120keV to a total dose range of $1\times 10^{17}$ions/$\textrm{cm}^2$ to $1\times 10^{18}$ions/$\textrm{cm}^2$ at various temperatures between $270^{\circ}C$ and $671^{\circ}C$. The microstructure changes by nitrogen implantation were analyzed by XRD and AES and wear behavior was evaluated by performing ball-on-disc type wear testing at various loads and sliding velocities under unlubricated condition. Nitrogen implantation produced ZrNx nitride above $3\times 10^{17}$ions/$\textrm{cm}^2$ as well as heavy dislocations, which resluted in an increase in microhardness of the implanted surface of up to 1400 $H_k$ from 200 $H_k$ of unimplanted substrate. Hardness was also found to be increased with increasing implantation temperature up to 1760 $H_k$ at $620^{\circ}C$. The wear resistance was greatly improved as total ion dose and implantation temperature increased. The effective enhancement of wear resistance at high dose and temperature is believed to be due to the significant hardening associated with high degree of precipitation of Zr nitrides and generation of prismatic dislocation loops.