• Analytical Science and Technology
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• v.15 no.3
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• pp.229-235
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• 2002

Plasma source ion implantation (PSII) technique was utilized to improve the wettability of polystyrene surfaces. It is well known that treated surfaces undergo aging, leading to hydrophobic recovery with time. We investigated the aging effect of polystyrene thin film on the various molecular weights. Polystyrenes with several molecular weights ($M_w$ = 760, 2430, 31600, 115700, 280000, 903600) were treated in different experimental conditions including gas species and pulse energy, and their hydrophilicity was measured by contact angle goniometer. To study wettability decay as a function of the molecular weight, PSII-treated samples were aged at different temperatures. Hydrophobic recovery of high molecular weight polystyrene was much slower than that of low molecular weight, even at high temperatures. The methods used to characterize treated surfaces were water contact angle measurement, TOF-SIMS, XPS, SEM and AFM.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.10
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• pp.61-70
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• 2006

A Supersonic air intake model was designed for the high performance ramjet and dual-mode scramjet engine to operate at Mach 4 flight condition. The air intake was tested in the blowdown-type wind tunnel of Kyushu University to identify the internal flow characteristics corresponding to the flight parameters such as the back pressure, angle of attack and angle of yaw. Flow visualization was achieved by the Schlieren and oil flow visualization techniques. The intake performance was analyzed quantitatively based on the surface pressure and total Pressure measurements. The experimental results were compared with the computational fluid dynamics results. The present study exhibits the fundamental but rarely found experimental results of the high Mach number supersonic air intake.

• Journal of the Korean Society of Radiology
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• v.8 no.7
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• pp.397-400
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• 2014

This study purpose is to know about the effect of Cobb's angle of scoliosis patient by Pilates ecercise. It was executed for prove this exercise with Pilates Postural Correct Exercise(PCE), Spine Stretching Exercis(SSE), Muscle Strengthing Exercise(MSE). PCE is useful for unbalanced muscle energy and SSE gives relax for hypertensioned muscles and MSE is correcting balance for prime mover and secondary mover and so it will be recovery for elasticity and flexibility of paraspine muscles. The method study was proved with a Cobb's angle measurement of Lumbar spine by X-ray test before and after. As a result for the test, Cobb's angle by X-ray it shows reduced about 5 degree in statistics(p=0.005). And so It shows the Pilates exercise gives reduce for Scoliosis.

• Journal of the Korean Society of Physical Medicine
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• v.15 no.1
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• pp.43-54
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• 2020

PURPOSE: This study examined the effects of mild-intensity exercise (MIE) and high-intensity interval exercise (HIIE) on the recovery of the motor function over time in sciatic nerve crush injury rats. METHODS: The MIE group ran on a treadmill at a speed of 8.3 m/min to perform low-intensity training with maximum oxygen uptakes ranging from 40 to 50%. The HIIE group ran on the treadmill at a speed of 25 m/min to perform high-intensity training with a maximum oxygen uptake of 80%. The interval training was performed based on a 1:1 work-to-rest ratio. The effects of each form of exercise on the rats' walking abilities following their recovery from the peripheral nerve injuries were evaluated based on the results of behavior tests performed at one and 14 days. RESULTS: According to the test results, the MIE group showed significant improvements in the rats' ankle angle in the initial stance phase, and in the ankle and knee angles in the toe-off phase (p<.05). The HIIE group exhibited significant improvements in the ankle and knee angles in the initial stance phase, SFI(p<.05). CONCLUSION: The state of such patients can be improved by applying the results of this study in that MIE and HIIE on a treadmill can contribute to the recovery of the peripheral nerve and motor skill. In particular, MIE is used as a walking functional training in the toe-off stance phase, while HIIE is suitable in the initial stance stage.

• Journal of the Ergonomics Society of Korea
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• v.14 no.1
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• pp.9-23
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• 1995

The objectives of the study were twofole: (1) to investigate effects of rhythmic contraction and sustained contraction methods on recovery rate of isometric endurance capacity and (2) to compare aptterns of muscle recruitment of both arms observed during each contraction period. In the experiment, each of two subjects performed five successive rhythmic or sustained isometric contractions at 50% MVC with both arms to the point of fatigue, which was the failure to maintain the required tension. In making the contractions, the subjects stood erect with upper arms held at an angle of approximately 90 .deg. to the forearm. The interval between the successive contractions was kept constant at 3, 7, 20, or 40 minutes. Regardless of the contraction methods, the recovery rate was least at the shortest interval and was highest at the longest interval. However, a statistical analysis showed that the recovery rates for the rhythmic contractions were significantly lower than those for the sustained contractions throughout 4 different intervals. Furthermore, as the frequency of the rhythmic contractions per min, increased 4 to 6 times, the recovery rate of isometric endurance capacity decreased. From an EMG anglysis, recruitment pattern of the muscules of both arms was found to be common between two different contraction methods. The biceps muxcles of the upper arms played a major role in exerting 50% MVC, while the brachioradialis muscles of the forearms acted as synergists. As the contraction proceeded, the role of the biceps muscles as a prime mover lessened due to the fatigue. Then, the brachioradialis muscles exerted more strength to sustain 50% MVC. The implications of these finding were discussed.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.1
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• pp.6-14
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• 2007

Modem version of supersonic jet fighter aircraft must have been guaranteed appropriate controllability and stability in HAoA(High Angle of Attack). Limit value of aircraft entering into the departure in HAoA is related to aircraft configuration design. But, the control law such as AoA and yaw-rate limiter is implemented in digital Fly-By-Wire flight control system of supersonic jet fighter to guarantee the aircraft's safety in HAoA. The HAoA flight control law have two parts, one is control law of departure prevention and the other is control law of departure recovery support. The control laws of departure prevention for advanced jet trainer consist AoA limiter, roll command limiter and rudder fader. The control laws of departure recovery support are consist yaw-rate limiter and MPO(Manual Pitch Override) mode. The guideline of pitch rocking using MPO mode is simple, but operating skill of pitch rocking is very difficult by the pilot with inexperience of departure situation. This paper addresses the design and validation of APR(Automatic Pitch Rocker) control law instead of MPO in order to automatic recovery without manual pitch rocking by the pilot. And, recovery characteristic with APR verifies by the nonlinear analysis and pilot evaluation.

• Korean Journal of Applied Biomechanics
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• v.21 no.3
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• pp.259-268
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• 2011

This study aimed to examine the kinematic characteristics of the national elite cross-country skiers' double poling technique and to provide the quantitative data for better performance. Four male elite cross-country roller skiers skied maximum velocity with Double Pole technique. The cycle characteristics with angles of elbow, hip, and knee joint were analyzed. The results showed that CM velocity of the body was increased with the third cycle, the cycle time and length were also increased. The poling time and recovery time rate showed with 32.79%, 67.44% respectively. The joint angles with elbow, hip and knee were $106^{\circ}$, $133.14^{\circ}$ $156.87^{\circ}$ at pole in event, $158.94^{\circ}$, $65.7^{\circ}$, $140.19^{\circ}$ at pole out event. Elite skiers should decrease double poling time rate and increase recovery time rate in order to improve the double poling performance. The cycle length and velocity of the double poling should be increased for the better performance. The elbow angle should be minimized at pole in event with maximum extension until pole out event. The hip and knee angles should be increased for the recovery phase.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.4
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• pp.71-77
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• 2008

This paper presents a methodology for recovering the industrial radiographic images from the effects of nonlinear distortion. Analytical approach based on the inverse square law and Beer's law is developed in order to improve a mathematic model of nonlinear type. The geometric effect due to dimensions of the radioactive source appeals on the digitized images. The relation that expresses parameters values(angle, position, absorption coefficient, length, width and pixel account) is defined in this model, matching with the sample image. To perform the search for image recovery most similar to the model, a correction procedure is designed. The application of this method on the radiographic images of steel tubes is shown and recovered results are discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.216-219
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• 2002

Much quantity of anti-tracking agent, ATH is added to the silicone rubber for the protection of silicone rubber against surface discharge. Hydrophobicity recovery properties of silicone rubber could be different by the content, surface treatment state and particle size of ATH. Because hydrophobicity of silicone rubber is depend much on the surface state of ATH. In this paper, the properties of silicone rubber is investigated according to the addition of different particle size of ATH to the silicone rubber. Hydrophobicity recovery properties and arc resistance of silicone rubber were investigated according to the addition of different particle size of ATH. Hydrophobicity recovery properties of silicone rubber were evaluated by the measurement of contact angle.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.10
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• pp.465-472
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• 2002

This paper presents a study on the aging and recovery of HTV (high temperature vulcanized) silicone rubber used for outdoor insulators. UV irradiation, corona discharge and water immersion were employed as factors of the artificial aging. The effects of changes derived from these stresses on the tracking and arc resistance of silicone rubber were examined. We have investigated the aging phenomena of HTV silicone rubber by the above stresses using the surface energy calculation with contact angle measurement, solvent-extraction, and surface/volume resistivity and so on. These results showed that UV irradiation and corona discharge lead to nearly the same surface oxidation, but the percentage change of mobile low molecular weight by these stresses was different. Furthermore, the oxidized layer induced under UV irradiation restricted the recovery of hydrophobic surface. Water immersion little lowered hydrophobicity level and leaded to a loss of tracking and arc resistance. The degradation mechanism based on our results was discussed.