• Journal of Korea Foundry Society
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• v.2 no.1
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• pp.12-18
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• 1982

The present investigation was made to abtain a fine distribution of Pb Particles in AL - Pb binary alloys , which have a broad miscibility gap and large specific difference, by means of rapid Cooling of the molten alloys. Al-2.4% Pb, Al-5.5wt% Pb and Al-8.0wt % Pb alloy were used. The rapid cooling operation was performed by free falling of homogeneous liquid Al-Ph alloys into the water-cooled copper mold, and thermal analysis was made. Microstructures were observed, and variations of size and number of Pb particles were analysicle analyzer. By the result of examination with the varing cooling rates 100 to $210^{\circ}C/sec$ fine distributions of Pb particles were obtained with high cooling rate. Under same cooling condition, the best rapid cooling effect was recognized in Al-5.5wt% Pb alloy.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.491-495
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• 2015

Currently, selfie stick, a monopod take selfie photographs, got its popularity. Cradle used to connect selfie stick and smartphone usually uses electric force of spring to get smartphone fixed. But, using electric forces makes it hard to attach and detach smartphone from the cradle and gives possibility of smartphone falling down. CoQue suggests new solution of smartphone cradle by using cable tie (patent number US 8407863 B2) instead of electric force. It will give more easy and stable way of using selfie stick.

• Fibers and Polymers
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• v.7 no.2
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• pp.195-202
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• 2006

Tight-fitting clothing pattern reflecting the accurate information of the 3D body shape has been one of the challenges for garment industry, however, fitting problems still exist. The objectives of the paper is to develop a 2D pattern which fits tightly to the 3D human scan data for sports suits that need comfort and function for maximum performance. In this study, the user graphic interface application software for the semi-automatic garment pattern generation has been implemented using the triangle simplification scheme together with 2D projections of free-falling of 3D surface polygons keeping the original 3D surface area preservation. A typical application of the developed pattern to the functional body suits is presented and verification of the proposed method is also provided.

• Journal of the Korean Chemical Society
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• v.43 no.3
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• pp.251-256
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• 1999

Viscosities of toluene were experimentally determined by the falling-ball method at several temperatures and pressures to investigate the pressure and temperature dependence of the viscosity of toluene. With the shear stress of the viscous flow of toluene, the shear free energy, the shear entropy, and the shear enthalpy were defined to discuss the variations of the shear thermodynamic properties with pressure. The effect of temperature and pressure on the shear thermodynamic properties obtained experimentally can be explained by means of the molecular thermal agitation due to temperature incleasing and the steric effect of the closed molecules of to Iuene due to pressure elevation.

• Proceedings of the Korean Society of Computer Information Conference
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• 2012.01a
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• pp.59-60
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• 2012

자유 낙하하는 물체가 받는 힘은 중력 뿐이다. 우리는 중력만을 받아서 운동하는 것을 자유 낙하 운동이라고 하고 자유 낙하하는 물체를 자유낙체라 한다. 다시 말해서, 물체의 초기 운동 상태와 무관하게 중력의 영향으로만 자유롭게 낙하하는 물체를 말하는 것이다. 본 논문에서는 공기의 저항을 무시하고, 수직방향으로 짧은 거리의 범위 내에서 고도에 의한 자유낙하 가속도의 변화가 없다는 가정을 하고, 자동차가 수직 상 방향으로 출발하여 도약하고 최고점에 도달하는 시간, 최대높이, 자동차가 출발 위치로 돌아오는 시간과 자동차의 속도, 자동차가 땅에 떨어질 때의 시간 및 속도에 대해 알 수 있다.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.153-156
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• 2005

Surface dry condition examination method on the KS F 2504(Testing method for specific gravity and absorption of fine aggregate) has dim detail prescriptions which can cause different ways of understanding based on one's convinence, not on correct means of rule. So we investigate the problems about the inconsistency on decisioing surface dry condition at management examination in the lab and scene. In conclusion, free-falling method is easier and faster than self-weight method. And we also found that the most important face on decisioning surface dry is compacting factor of tamping rod.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.71-78
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• 2002

The N-value from the standard penetration test(SPT) is affected by the magnitude of the rod penetration energy transmitted from the falling hammer as well as the geotechnical characteristics of the ground. Understanding of the striking energy efficiency in the SPT equipment is getting important for that reason. The energy efficiencies of the various type of equipment were investigated through field tests using the instrumented rod and wave-signal acquisition systems including the pile driving analyzer(PDA). The rod energy ratio, ERr was defined as the ratio of the energy delivered to the drilling rod to the potential free-fall energy of the hammer. It appears that the type of the hammer and lift/drop system had a strong influence on the energy transfer mechanism and ERr also varies according to the energy instrumentation system and the analysis methods.

• 한국기계연구소 소보
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• s.20
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• pp.27-32
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• 1990

A counter balance valve is used as one part of hydraulic motor brake system. The function of this valve is to protect over-run or free falling of inertia load. But occasionally the brake system with counter balance valve makes some undesirable problems such as pressure surges or vibrations. In this study, for the purpose of easy estimation about dynamic chrcteristics of hydraulic system including counter balance valve, precise formulation describing fluid dynamics and valve dynamics under various boundary conditions were made. dynamic caracteristics were analysed by numerical intergration using Runge-Kutta method, because the equations in this circuit with counter balance valve contain various nonlinear terms. So the analyzing method developed in this study enabled very easy estimating the relation between the performance of counter balance valve and various physical parameters related to the valve.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.135-136
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• 2011

자유낙체란 자유로이 낙하하는 물체를 말한다. 즉 물체의 초기 운동 상태와 무관하게 중력의 영향으로만 자유롭게 낙하하는 물체를 말하는 것이다. 본 논문에서는 공기의 저항을 무시하고, 수직방향으로 짧은 거리의 범위 내에서 고도에 의한 자유낙하 가속도의 변화가 없다고 가정한다. 이러한 가정 하에, 자동차가 수직 상 방향으로 출발하여 최고점에 도달하는 시간, 최대높이, 자동차가 출발 위치로 돌아오는 시간과 자동차의 속도, 자동차가 땅에 떨어질 때의 시간 및 속도에 대하여 알아본다.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.1186-1190
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• 2006

Rising in important of alternative energy due to the recenfly high oil price and environment problem. Application of alternative energy has become higher than before. In this study, facility test of Geothermal energy to bankfiltration was examined appliying changwon pumping well. Initial installation cost was efficiently saved by connecting a heat pump system to pumping well in changwon bankfiltration site. A falling-off in efficiency of heat pump was free due to the bankfiltration that is rare for the temperature fluctuation. Therefore, Heat soure as bankfiltration system solve the existing facilities problems of geothermal heat pump system.