• 열처리공학회지
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• 제4권3호
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• pp.1-6
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• 1991

In this study, intermediate thermo-mechanical treated Al-2.0 wt%Li, and Al-2.0 wt%Li-1.2 wt%Cu-1.0 wt%Mg-0.12 wt%Zr alloys were tested in tension at $10^{\circ}C$ and elevated temperature(100, 200 and $300^{\circ}C$). The results are follows : The tensile strength of Al-Li-Cu-Mg-Zr alloy is the highest but the elongation of Al-Li alloy is the highest(106%) among the all alloys in tension at $300^{\circ}C$. The Portervin-LeChartlier effect is showed in AI-Li-Cu-Mg-Zr alloy at 10 and $100^{\circ}C$, because of tangled dislocation by Mg and Cu. In the true stress-strain curves of all alloy, the peaks of stress at $300^{\circ}C$ are showed at the strain less than 0.1. In the binary alloy, the dynamic restoration process at 200 and $300^{\circ}C$ is nearly similar to dynamic recovery type. The hot deformation stress is decreased with increase of dynamic recovery degree, but the elongation is increased. When the strain the strain rate are constant, the temperature dependence of hot deformation stress is increased with increase of deformation temperature. The elongation and degree of dynamic recovery are decreased with increase of hot deformation activation energy, but the deformation stresses slightly increased.

• 한국융합학회논문지
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• 제12권12호
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• pp.401-409
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• 2021

이 연구는 천안시 태조산의 산림 경사 트레킹 시 80bpm 및 130+30bpm의 속도로 걷기 운동 후 정적회복 및 동적회복방법이 회복 중 심박수, 혈중젖산농도, 혈중글루코스에 미치는 영향을 분석하여 산림환경의 경사 트레킹 후 효율적인 회복방법을 알아보고자 하였다. 걷기 운동을 하는데 이상이 없는 20-30대 남자 9명을 대상으로 80bpm 속도와 130+30bpm 속도로 트레킹 후 정적회복방법과 동적회복방법에 따라 얻은 결과를 이원 반복측정 분산분석(Two-way repeated ANOVA)방법으로 분석하였으며, 유의한 차이가 나는 경우 contrast의 repeated 방법을 적용하여 비교 분석하였다. 80bpm 조건에서의 심박수는 방법(p=.008)과 시기(p=.000)에 따라 유의한 차이가 있었으며, 혈중젖산농도는 회복방법에 따라 유의한 차이가 없었으나(p=.401), 시기에 따라 유의한 차이가 나타났다(p=.000). 혈중글루코스는 회복방법에 따라 유의한 차이가 나타나지 않았으며(p=.093), 정적회복방법의 시기에서 유의한 차이가 나타났다(p=.002). 130bpm+30bpm 조건에서의 심박수는 방법(p=.002)과 시기(p=.000)에 따라 유의한 차이가 있었으며, 혈중젖산농도는 방법(p=.001)과 시기(p=.000)에 따라 유의한 차이가 나타났고, 혈중글루코스농도는 방법(p=.721)과 시기(p=090)간 유의한 차이가 나타나지 않았다.

• 소성∙가공
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• 제8권2호
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• pp.169-177
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• 1999

Different pass strains and rolling temperatures were applied to understand the effects of pass strain and rolling temperature on flow stress and flow strain of AA5083 alloy. The specimens were prepared by conventional casting process followed by hot rolling. Hot torsion tests were conducted at temperature ranges of 350 to 52$0^{\circ}C$ under a strain rate of 1.0/sec. During the process, hot-restoration mechanisms, dynamic recovery(DRV) or dynamic recrystallization (DRX), of the AA5083 alloy were analyzed from the flow curves and deformed microstructures. It was found that while the rolling strain per pass and rolling temperature have little effect on the folw stress, they have significant effect on the failure strain. The DRV was responsible for the hot restoration mechanism of the hot-rolled specimen. heavily elongated grains and small subgrains containing dislocations were obtaned during the hot deformation. This was due to the presence of Al6Mn precipitate in the alloy.

• 대한물리치료과학회지
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• 제11권2호
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• pp.38-45
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• 2004

Appropriate physical position and balance means giving the least stress and the most useful biomechanically to the body. As this fails, one would have functional recovery problem regardless of disability. There reported better effective on Dynamic training rather than Static training for a proper recovery of physical position, and additionally required Sensory Feedback. Those who have disability of balance, especially Central Nervous System lesion should he provided with variety of Sensory Feedback, and also Dynamic Balance training used by is quite effective.

• 대한산업공학회지
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• 제31권3호
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• pp.240-247
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• 2005

Today's hightech society requires thousands of different products which ultimately result in billions of tons of materials discarded, most of which end up in landfills. Therefore industrial circles could not help thinking about environmental problems by regulations of government or pressures of consumer. Generally, the related research subjects are classified into both of environmentally conscious manufacturing and product recovery, where product recovery aims to minimize the amount of waste sent to landfills by recovering materials and parts from old or outdated products by means of recycling and remanufacturing (including reuse of parts and products). In this research, we constructed a model for remanufacturing various goods using a single facility and developed a dynamic programing(DP) algorithm based upon the optimal solution characterization. We showed the efficiency of the developed DP algorithm with a numerical example.

• 한국응용과학기술학회지
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• 제37권6호
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• pp.1646-1658
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• 2020

이 연구의 목적은 운동 후 수중회복방법의 차이가 성장호르몬, 테스토스테론, 혈중젖산농도, 심부담도, 통증의 변화를 알아보는 것이다. 저항운동 경력 6개월 이상인 남자 7명을 대상으로 집중 웨이트 트레이닝과 서킷 웨이트트레이닝을 1RM의 60%강도로 실시한 다음 회복방법으로 수중걷기회복과 수중앉기 회복을 진행하였다. 성장호르몬은 모든 운동형태와 회복방법에서 운동 후, 회복 후, 안정 시 순으로 높게 나타났으며, 테스토스테론은 운동 후, 회복 후, 안정 시 순으로 높았다. 혈중젖산농도는 모든 운동형태와 회복방법에서 운동 후, 회복 후, 안정 시 순으로 높았으며 집중저항운동 후 동적회복이 정적회복보다 낮았다. 심부담도는 모든 운동형태와 회복방법에서 운동 후, 회복 후, 안정 시 순으로 높았다. 근통증은 모든 운동형태와 회복방법에서 운동직후, 회복 후, 24시간, 48시간, 72시간 순으로 감소하였다. 물속 환경에서도 동적회복이 정적회복보다 근피로 개선에 효과가 있는 것으로 사료된다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제14권4호
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• pp.322-331
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• 2014

Chaotic dynamics is an active area of research in biology, physics, sociology, psychology, physiology, and engineering. This interest in chaos is also expanding to the social scientific fields such as politics, economics, and argument of prediction of societal events. In this paper, we propose a dynamic model for addiction of tobacco. A proposed dynamical model originates from the dynamics of tobacco use, recovery, and relapse. In order to make an addiction model of tobacco, we try to modify and rescale the existing tobacco and Lorenz models. Using these models, we can derive a new tobacco addiction model. Finally, we obtain periodic motion, quasi-periodic motion, quasi-chaotic motion, and chaotic motion from the addiction model of tobacco that we established. We say that periodic motion and quasi-periodic motion are related to the pre-addiction or recovery stage, respectively. Quasi-chaotic and chaotic motion are related to the addiction stage and relapse stage, respectively.

• 대한기계학회논문집B
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• 제24권7호
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• pp.994-1001
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• 2000

The dynamic behavior of a single-pressure heat recovery steam generator and turbine system for the combined cycle power plant is simulated on the basis of one-dimensional unsteady governing equations. A water level control and a turbine power control are also included in the calculation routine. Transient response of the system to the variation of gas turbine exit condition is simulated and effect of the turbine power control on the system response is examined. In addition, the effect of the treatment of inertia terms(fluid inertia and thermal inertia of heat exchanger metal) on the simulated transient response is investigated.

• 전기학회논문지P
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• 제67권4호
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• pp.208-213
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• 2018

In this paper, we studied the control strategy of applying STATCOM(static synchronous compensator) to mitigate the FIDVR(fault induced delayed voltage recovery) phenomenon. The proportion of motor loads is gradually increasing which might affect power system stability. Excessive reactive power consumption by the stall of the motor loads causes FIDVR phenomenon. In addition, the low inertia of the small HVAC(heating, ventilation and air conditioner) unit will not separate itself in the event of a contingency, causing system instability. For this reason, we have developed a control strategy that utilizes STATCOM efficiently through static and dynamic analysis. Case studies on a Korean power system have validated the performance of the proposed scheme under severe contingency scenarios. The results have verified that the proposed strategy can effectively mitigate FIDVR and improve the stability and reliability of the system.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.1066-1069
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• 2002

Dynamic postural control varies with the environmental context, specific task and intentions of the subject. In this paper, dynamic postural control against forward-backward perturbations of a platform was estimated using tri-axial accelerometers and a force plate. Ten young healthy volunteers stood upright in comfortable condition on the perturbation system which was controlled by an AC servo motor. With anterior-posterior perturbations, movements of ankle, knee and hip Joints were obtained by tri-axial accelerometers. and ground reaction forces with corresponding displacements of the center of pressure(CoP) by the force plate. The result showed that the ankle moved first and the trunk forward, which implies that the mechanism of the dynamic postural control in forward-backward perturbations, occurred in the procedure of the ankle, the knee and the hip. Knee flexion and hip extension in the period of acceleration, constant velocity and deceleration phase is very important fur the balance recovery. These responses depends on the magnitude and timing of the perturbation. From the present study the accelerometry-system appears to be a promising tool for understanding kinematic accelerative In response to a transient platform perturbation. A more through understanding of balance recovery mechanism may aid in designing methods for reducing falls and the resulting injuries.