• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.149-149
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• 2010

The origin of the inhomogeneous distribution of photoluminescence (PL) peak wavelength on a commercial 2" GaN wafer for green light emitting diode has been investigated by wide momentum transfer (Q) range x-ray diffraction (XRD) profile of InGaN/GaN multiple quantum wells. Near the GaN (0004) Bragg peak, wide-Q range XRD (${\Delta}Q$ > $1.4{\AA}-1$) was measured along the growth direction. Wide-Q XRD gives precise and direct information of ultra-thin InGaN quantum well structure. Based on the QW structural information, the variation of PL spectra can be explained by the combined effect of temperature gradient and slightly uneven flow of atomic sources during the QW growth. In narrow variations of indium composition and thickness of QW, an effective indium composition can be a good character to match structural data to PL spectra.

• 한국자동차공학회논문집
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• 제14권2호
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• pp.184-193
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• 2006

Rotation of intake and exhaust valves are very closely related to the long term durability of automotive engines. If the valves do not rotate even at a rated engine speed, it causes the uneven wear of the valve seat and valve head contact area, which eventually shortens the engine life. A principle of valve rotation mechanism was presumed based on some findings from experiments, and computer programs were developed to simulate the valve rotation phenomena. In this study we investigated the valve rotation mechanism by using the computer simulation models.

• Tribology and Lubricants
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• 제15권2호
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• pp.199-205
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• 1999

Using a coupled thermal-mechanical analysis, the thermal distortion of the ventilated disk brakes has been investigated based on the air cooling effects during 15 braking operations. The FEM results show that the bendings and distortions of the disk toward the left side are decreased, but the sinusoidal distortion of the disk rubbing surface along the arc length of the vent hole is highly increased by increasing the convective air cooling effects, which is heavily related to the squeal, wear and micro-thermal crackings at the rubbing surfaces due to uneven dissipation rates of friction heatings.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.247-253
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• 2005

In this stydy, the characteristics of the spatial location based on rural environment pollution facilities which can cause environmental pollution and thus lower the value of rural amenity was analyzed. This study showed that livestock feedlot occupied the highest percentage among the facilities analyzed and the size of facilities increased with increasing distance from the residential area. In addition, the facilities showed two typical characteristics in terms of their spatial distribution; uneven and even distribution which are characterized by concentrated distribution in a certain area and by scattered distribution in a wide area, respectively. As the facilities including livestock feedlot have a great potential to cause environmental problem such as air, water, soil and noise pollution, it is necessary to develop systematic plans for the management and improvement of the facilities.

• 한국작물학회지
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• 제36권5호
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• pp.459-480
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• 1991

인삼의 생리장해를 산지중심으로 증상별로 종합검토하였다. 뿌리의 장해는 적피, 은피, 동해, 동해, 근부, 안삼, 출아불재, 달래삼, 소수가 있고 지상부에는 황엽, 조기낙엽, 소엽, 지엽, 백반엽, 동해, 풍해와 경열이 있다. 적피와 황엽이 인삼생산에 가장 크게 영향한다. 농약해, 붕소과 잉해 및 산업공해에 의한 피해 경우도 보고되었다. 원료수삼 가공한 후의 품질요인에 관계되는 생리장해들도 검토하였다.

• 패션비즈니스
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• 제15권4호
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• pp.110-121
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• 2011

As car seat is the closest part between driver and rider, the interest of the security and comfort of the seat is increasing. This research discovered the best condition for dyeing and finishing to produce a fabric for car seat and also developed the design of fabrication to give the feeling from such a finishing. The best condition of coating finishing solution is aqueous PU 65%, dye resist reagent 20%, water 12%, thicker 3%, and knife thickness 2mm, tenter temperature $170^{\circ}C$, tenter speed 35yard/min, viscosity 12,000cps and stirring time 100kg * 30min. According to the processing time of knife coating upon stirring the change of resin and the uneven of coating quantity was shown. This problems will be solved by means of automatic temperature control apparatus for resin and sealing device through a coming research.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권3호
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• pp.131-140
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• 2005

Fault-tolerant gait generation of a hexapod robot with crab walking is proposed. The considered fault is a locked joint failure, which prevents a joint of a leg from moving and makes it locked in a known position. Due to the reduced workspace of a failed leg, fault-tolerant crab walking has a limitation in the range of heading direction. In this paper, an accessible range of the crab angle is derived for a given configuration of the failed leg and, based on the principles of fault-tolerant gait planning, periodic crab gaits are proposed in which a hexapod robot realizes crab walking after a locked joint failure, having a reasonable stride length and stability margin. The proposed crab walking is then applied to path planning on uneven terrain with positive obstacles. i.e., protruded obstacles which legged robots cannot cross over but have to take a roundabout route to avoid. The robot trajectory should be generated such that the crab angle does not exceed the restricted range caused by a locked joint failure.

• Transactions on Electrical and Electronic Materials
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• 제8권2호
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• pp.97-102
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• 2007

The charging/discharging characteristics of electric double layer capacitors (EDLCs) for an electric power storage device application were investigated. The specific area of the carbonaceous electrode surface by the BET method was in the range of $1800{\sim}2000\;m^2/g$. The charge distributions during charging and discharging were measured by means of a pulsed-electro-acoustic (PEA) method, and the voltage characteristics of EDLCs connected to solar cells were evaluated. The results showed that the distributions of positive and negative charges were spatially uneven, which was due to the mobility of the positive and negative charges in the carbonaceous electrode surface of the EDLCs. The charge accumulation region concentrated on central part of the carbonaceous electrode and the required times for charging and discharging were almost same.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.567-571
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• 2004

The 2-dimensional unsteady flows on and around the cambered airfoils were computed by applying LES with the deductive dynamic SGS model. The unsteady flow field were used as inputs to compute the far-field sounds and directivity patterns from rotating blades by a hybrid approach that exploits Farassat's formula. The BEM (Boundary Element Method) was applied to predict the frequency characteristics from the rotating blades for the cases of even- and uneven-pitched fans. The BEM results suggested that the unevenly pitched fan have less pronounced discrete peaks at BEF frequencies, which was confirmed by the experiment.

• International Journal of Control, Automation, and Systems
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• 제6권4호
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• pp.551-558
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• 2008

This paper deals with the real-time stable walking for a humanoid robot, ISHURO-II, on uneven terrain. A humanoid robot necessitates achieving posture stabilization since it has basic problems such as structural instability. In this paper, a stabilization algorithm is proposed using the ground reaction forces, which are measured using FSR (Force Sensing Resistor) sensors during walking, and the ground conditions are estimated from these data. From this information the robot selects the proper motion pattern and overcomes ground irregularities effectively. In order to generate the proper reaction under the various ground situations, a fuzzy algorithm is applied in finding the proper angle of the joint. The performance of the proposed algorithm is verified by simulation and walking experiments on a 24-DOFs humanoid robot, ISHURO-II.