• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.3
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• pp.259-264
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• 2014

This paper is research paper on the MPD(Magnet Position Device) for the outdoor MGV(Magnet /Magnet Gyro Guidance Vehicle). Usually, MGV is used in indoor environment because of a measurement height of the magnet position device. CMPD(Commercial magnet position device) has 30 mm measurement height, so this is suitable structure in indoor environment like to a flat surface. Outdoor environment is an uneven and irregular, So Outdoor MGV must has a suspension. But CMPD is unsuitable for outdoor environment because of a collision with a surface caused by suspension. Thus, measurement height of the outdoor MPD is positively necessary more than 100 mm. So, we suggest the outdoor MPD using analog magnet hall sensor, moving average filter and Characteristic(rate of the magnet hall sensor) function of the localization. Result of the experiments, the proposed Magnet Position Device for the outdoor MGV has localization accuracy 4.31 mm, measurement height 150 mm and width 150 mm and is efficient more than CMPD.

• Journal of Korean Society of Steel Construction
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• v.13 no.4
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• pp.381-393
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• 2001

The current traffic situation in Korea can be described as rapid change in traffic volume and diversity in vehicle size from compact cars to large trucks. W-beam barrier most widely used in Korea was found not to satisfy the stiffness requirement for the Koran impact condition of 14 ton-60Km/h-15deg. and it was too stiff for small vehicles impacting with more realistic speed to satisfy the safety of vehicle occupants. To develop a guardrail system satisfying the two contradicting goals, a thrie-beam guardrail system, which had the beam thickness of 3.2mm and rubber cushions, was conceived. Even though the height of the thrie-beam(450mm) is increased by 100mm as compared to that of W-beam (350mm), there was only 2% increase in the weight of the thrie-beam. The new thrie-beam barrier system could contain more wide range of vehicle bumper heights, and showed better performance in the viewpoint of stiffness and energy absorbing capability than the W-beam system. The impact performance was evaluated from a crash test. The developed thrie-beam guardrail system satisfied all applicable criteria for NCHRP 350 test designation 3-10.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.6
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• pp.587-593
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• 2008

Transdermal and topical drug delivery with minimal tissue damage has been an area of vigorous research for years. Our research team has initiated the development of an effective method for delivering drug particles across the skin (transdermal) for systemic circulation, and to localized (topical) areas. The device consists of a laser ablation based micro-particle acceleration system that can be integrated with endoscopic surgical techniques. We have successfully delivered 3μm size cobalt particles into gelatin models that represent soft tissue with remarkable penetration depth.

• Journal of the KSME
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• v.37 no.10
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• pp.41-46
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• 1997

철강구조물 부재 내에 노치나 균열이 존재할 수 있고, 외부의 피로하중에 의하여 취약부에서 발생한 균열이 진전하여 전구조물의 최종파손을 야기시킬 수 있다. 부재를 보다 안전하게 사용하고 또한 신뢰성을 확보하기 위해서는 이미 손상된 부재에서 균열의 진전상태를 계측할 수 있는 방법이 확립되어져야 하고, 파괴역학적 파라미터를 이용한 사용재의 균열진전거동특성이 평가되어야 한다. 균열길이의 측정방법은 지금까지 많은 연구자들에 의하여 개발되어져 왔는데 크게 광학현미경을 이용하여 육안으로 직접 균열길이를 측정하는 방법과 컴플라이언스, 초음파, AE 또는 전기적 신호를 통하여 얻어진 결괄부터 균열길이로 환산하는 간접적인 방법으로 대별된다. 대부분의 균열길이의 측정방법은 많은 수작업이 요구되고, 특히 하한계응력확대계수영역의 미세한 균열진전량을 측정하기에는 어려움이 따르고 있다. 이에 대하여 전도체 시험편에 일정전류를 흐르게 하고 균열길이의 증가에 따라 변화하는 전위차로 이를 균열길이로 평가하는 전기적인 측정방법이 있다. 이 방법은 실험장치가 비교적 간단하고 미세한 균열길이의 측정이 용이하여 균열길이의 직접적인 측정이 곤란한 고온역 그리고 충격하중하에서의 균열길이 측정에 이용이 확대되고 있다. 이 글에서는 여러 균열길이 측정방법의 장.단점에 대하여 고찰하고, 그 중 많은 장점을 갖고 있는 직류전위차법의 실험방법을 소개한다.

• Journal of Energy Engineering
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• v.9 no.3
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• pp.178-183
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• 2000

본 연구에서는 유동과 냉각수를 이용하는 아이슬러리 제조관정을 관찰하고, 이 시스템의 가장 큰 문제점인 관내동결 특성을 파악하였다. 시험수로는 수도수(city water)를 이용하였다. 시스템을 순환하는 시험수가 제빙관내에서 $0^{\circ}C$ 이하의 과냉각 조건이 형성되어 제빙관을 빠져 나오면서 축냉조에 설치된 충격판상에서 과냉각 해소가 일어났다. 이때 유동과냉각수는 내부에너지를 방출하면서 그 일부가 얼음 입자로 상변화되었고, 나머지는 실험장치를 계속순환하였다. 제빙관에서 시험수와 브라인의 열교환 방식을 대향류와 평행류 두 조건에서 시험수의 과냉각도는 Reynolds 수가 증가함에 따라 감소하는 경향을 보였고, 이들 결과 값으로부터 각각의 관계식을 유도하였다. 또한 브라인의 냉각속도가 0.29~0.53[$^{\circ}C$/min] 범위에서 시험수의 과냉각도는 브라인 냉각속도에 종속되지 않았다.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.05a
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• pp.290-291
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• 2023

모빌리티 기술의 발전으로 자율주행 및 센서 데이터 처리를 위한 신뢰할 수 있는 고성능 저장 시스템의 수요가 증가하고 있다. SSD(Solid State Drive)는 빠른 데이터 처리 속도의 장점뿐만 아니라 외부 충격에 강한 내구성과 저전력의 특징 때문에 모빌리티 환경의 저장 시스템으로 사용되고 있다. 그러나 고온에 장시간 노출되면 NAND 플래시 메모리 소자에 손상이 발생할 수 있는 특성 때문에 모빌리티 내부 SSD의 온도를 관리해야 한다. 본 논문에서는 SSD의 외부 및 내부의 온도를 측정하여 저장장치가 고온에 장시간 노출되지 않도록 쿨링 시스템을 설계하고 실험을 통하여 적정 온도를 유지할 수 있는 최적화 방법을 제안한다. 또한 실험을 통해 쿨링 시스템이 SSD의 내부와 외부에 미치는 온도 변화를 측정하여 제안하는 시스템의 효과를 증명한다.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.4
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• pp.39-45
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• 2008

Breakaway support for small signs of size $0.293\;m^2{\sim}0.360\;m^2$ using indented tube type bolt of D12 mm with 6 mm inner diameter has been developed and the structural strength of the support system for the wind load was verified through static shear and tension tests. One important value in understanding the dynamic behavior of sign post and impact vehicle is the fracture energy of the sign support. In this study, fracture energy needed to break the sign support was estimated by pendulum test and computer simulation using LS-DYNA program. Support system composed of 3 indented bolts was found to sustain the 43.1 kg$\sim$51.2 kg wind load safely. Fracture energy for one indented bolt was measured as 163.3J from the pendulum test, and was calculated as 153J from the LS-DYNA simulation. The closeness between these two values verified the validity of the simulation model.

• The Journal of Engineering Geology
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• v.23 no.1
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• pp.29-36
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• 2013

The application of appropriate rehabilitation methods can improve the efficiency of clogged wells and extend their life. In this paper, we study the feasibility of well cleaning using high-voltage pulsed discharge, in which electrical energy is used to produce impulsive pressure in water, in contrast to conventional methods that employ chemical or pneumatic energy sources. This technique utilizes the compressive shock wave generated by the expansive force of hot, dense plasma that is produced during a pulsed discharge in the gap between electrodes immersed in water. Compared with conventional techniques, this method is simple, and easy to handle and control. Using a capacitive pulsed power system with an electrical energy of 200 J, an impulsive pressure of 10.7 MPa is achieved at the position 6 cm away from the discharge gap. The amplitude of the impulsive pressure was easily controlled by adjusting the charging voltage of the capacitor and was almost linearly proportional to peak discharge current. The technique achieved good results in cleaning feasibility tests with mock-up specimens similar to clogged well screens.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.363-366
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• 2011

Mixing and combustion experiments with a vent slot mixer were performed in Mach 2 supersonic wind tunnel. Helium and hydrogen gases each were used for the mixing and the combustion experiment with a plasma jet (PJ) torch. The vent slot mixer holds plenty of fuel in the downstream mixing region, even though the fuel is transversely injected. In case of the combustion, the injected fuel is ignited by the PJ torch, and then unburned mixture is burned by shock-induced combustion downstream. Thermal choking in the combustor leads to shock trains in the isolator, causing the unstable combustion.

• Tribology and Lubricants
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• v.27 no.3
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• pp.140-146
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• 2011

A miniature pendular type impact testing machine was designed and developed, adopting a magnetic powder brake in order to investigate tensile and shear behavior of a small solder ball at high speed. In this testing system, the potential energy of the pendulum is transferred into the impact energy during its drop. Then, the impact energy is transmitted through the striker which is connected to the push rods to push the specimen for tensile loading. The tensile behavior of lead-free solder ball in diameter of 760 ${\mu}m$ was successfully investigated in a speed range of 0.15 m/s~1.25 m/s using this designed device. The maximum tensile strength of the solder joint decreases with the loading speed in the testing condition. The maximum tensile strength of the joint was 56 MPa in the low speed region.