• 전기의세계
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• 제39권6호
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• pp.14-19
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• 1990

1. CAD system과 PROPS를 접속하여 CADsystem에서 Design된 surface를 사용할 수 있으며 Robot Kinematics를 graphic library화하여 surface배치 수상 및 path generation 및 animation을 통하여 가공작업을 위한 로보트 운동을 simulation할 수 있게 되었다. 2. Denavit-hartenberg transformation form에 의해 여러 Robot Kinematic을 일반적인 형식으로 library화 하였다. 3. 금형 가공의 공정들을 Menu로 만들어서 Expert system을 도입, 손쉽게 Interactive한 작업을 할 수 있게 하였다. 4. 차후의 연구 목표는 로보트 Calibration S/W의 개발 및 실현 그리고 Expert System을 이용한 Robot Program Generator의 완성을 통한 전체 Off-line programming System을 정립하는데 있다. 이를 위해서 더 실제적인 Tool Path Generation과 Expert System을 이용한 가공 조건의 결정 및 User Interface를 위한 Window가 개발되어야 한다. 5. 1차년도에 개발된 Robotonomic Tool System의 유연성을 확장시킨다. 실험결과를 바탕으로 공정 자동화 시스템을 확장시킨다. 6. 연마공정자동화에 필수적인 공구 및 공구 Tip의 표준화 및 자동교환장치를 개발한다. 7. 금형연마 Cell의 구성요소들간의 Interface 및 System Controller에서의 집적화를 시킨다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2000년도 제32회 추계학술대회 정기총회
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• pp.341-346
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• 2000

The effect of OTS(octadecyltrichlorosilane) SAM(self-assembled monolayer) on the micro-adhesion has been studied. OTS SAM was formed on the Si(100) surface and SPM (scanning probe microscope) tips with different radius of curvature were fabricated by a series of masking and etching processes. Pull-off forces of different tips on Si and OTS SAM surfaces were measured by SPM in different relative humidities. The surface of OTS SAM was changed to hydrophobic surface and the micro-adhesion force of OTS SAM was lower than that of pure Si. As the tip radius of curvature and the relative humidity increased. the micro-adhesion force increased. Based on the test results. the main parameter affected to the micro-adhesion was absorbed humidity on the surface.

• Journal of Korean Vacuum Science & Technology
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• 제3권1호
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• pp.54-58
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• 1999

We deposited diamond-like carbon (DLC) films using ion beam sputtering of a graphite target on flat substrates for use as a thin film field emitter. An n-type silicon wafer, titanium-coated silicon, and indium tin oxide (ITO) coated glass were used as a substrate. All films exhibited a sudden increase in the emission after a breakdown occurred at high voltage. The morphology of the films after the breakdown depended on the substrate. On ITO and Ti substrates, the DLC film peeled off upon breakdown, but on the Si substrate the surface melting due to breakdown resulted in the formation of various structures such as a sharp point, mound, and crater. By scanning the deformed surface with a tip anode, we found that the emission was concentrated at the deformed sites, indicating that the field enhancement due to the morphology change was responsible for the increased emission.

• International Journal of Control, Automation, and Systems
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• 제4권6호
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• pp.748-755
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• 2006

In this paper, a trade-off design and fabrication of IPMC(Ionic Polymer Metal Composites) as an actuator for a flapping device have been described. Experiments for the internal solvent loss of IPMCs have been conducted for various combinations of cation and solvent in order to find out the best combination of cation and solvent for minimal solvent loss and higher actuation force. From the experiments, it was found that IPMCs with heavy water as their solvent could operate longer. Relations between length/thickness and tip force of IPMCs were also quantitatively identified for the actuator design from the tip force measurement of 200, 400, 640, and $800{\mu}m$ thick IPMCs. All IPMCs thicker than $200{\mu}m$ were processed by casting $Nafion^{TM}$ solution. The shorter and thicker IPMCs tended to generate higher actuation force but lower actuation displacement. To improve surface conductivity and to minimize solvent evaporation due to electrically heated electrodes, gold was sputtered on both surfaces of the cast IPMCs by the Physical Vapor Deposition(PVD) process. For amplification of a short IPMC's small actuation displacement to a large flapping motion, a rack-and-pinion type hinge was used in the flapping device. An insect wing was attached to the IPMC flapping mechanism for its flapping test. In this test, the wing flapping device using the $800{\mu}m$ thick IPMC. could create around $10^{\circ}{\sim}85^{\circ}$ flapping angles and $0.5{\sim}15Hz$ flapping frequencies by applying $3{\sim|}4V$.

• Ocean and Polar Research
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• 제25권1호
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• pp.89-106
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• 2003

Analyses of tidal observations and a numerical model of the $M_2$ and $M_4$ tides in the Uldolmok waterway located at the southwestern tip of the Korean Peninsula are described. This waterway is well known fer its strong tidal flows of up to more than 10 knots at the narrowest part of the channel. Harmonic analysis of the observed water level at five tidal stations reveals dramatic changes in the amplitude and phase of the shallow water constituents at the station near the narrowest part, while survey results show a decreasing trend in local mean sea levels toward the narrow section. It was also observed that the amplitudes of semi-diurnal constituents, $M_2$ and $S_2$ are diminishing toward the narrowest part of the waterway. Two-dimensional numerical modeling shows that the $M_2$ energy flux is dominated by the component coming from the eastern boundary. The $M_2$ energy is inward from both open boundaries and is transported toward the narrow region of the channel, where it is frictionally dissipated or transferred to other constituents due to a strong non-linear advection effect. It is also shown that the $M_4$ generation is strong around the narrow region, and the abrupt decrease in the M4 amplitude in the region is due to a cancellation of the locally generated M4 with the component propagated from open boundaries. The superposition of both propagated and generated M4 contributions also explains the discontinuity of the M4 phase lag in the region. The tide-induced residual sea level change and the regeneration effect of the $M_2$ tide through interaction with $M_4$ are also examined.

• 한국전기전자재료학회논문지
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• 제22권8호
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• pp.632-636
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• 2009

The local oxidation using an atomic force microscopy (AFM) is useful for Si-based fabrication of nanoscale structures and devices. SiC is a wide band-gap material that has advantages such as high-power, high-temperature and high-frequency in applications, and among several SiC polytypes, 4H-SiC is the most attractive polytype due to the high electron mobility. However, the AFM local oxidation of 4H-SiC for fabrication is still difficult, mainly due to the physical hardness and chemical inactivity of SiC. In this paper, we investigated the local oxidation of 4H-SiC surface using an AFM. We fabricated oxide patterns using a contact mode AFM with a Pt/Ir-coated Si tip (N-type, 0.01-0.025 ${\Omega}cm$) at room temperature, and the relative humidity ranged from 40 to 50 %. The height of the fabricated oxide pattern (1-3 nm) on SiC is similar to that of typically obtained on Si ($10^{15}^{\sim}10^{17}$ $cm^{-3}$). We perform the 2-D simulation to further analyze the electric field between the tip and the surface. We demonstrated that a specific electric field (4 ${\times}$ $10^7\;V/m$) and a doping concentration ($^{\sim}10^{17}$ $cm^{-3}$) is sufficient to switch on/off the growth of the local oxide on SiC.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 춘계학술대회 논문집
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• pp.79-80
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• 2009

The local oxidation using an atomic force microscopy (AFM) is useful for Si-base fabrication of nanoscale structures and devices. SiC is a wide band-gap material that has advantages such as high-power, high-temperature and high-frequency in applications, and among several SiC poly types, 4H-SiC is the most attractive poly type due to the high electron mobility. However, the AFM local oxidation of 4H-SiC for fabrication is still difficult, mainly due to the physical hardness and chemical inactivity of SiC. In this paper, we investigated the local oxidation of 4H-SiC surface using an AFM. We fabricated oxide patterns using a contact mode AFM with a Pt/Ir-coated Si tip (N-type, $0.01{\sim}0.025\;{\Omega}cm$) at room temperature, and the relative humidity ranged from 40 to 50%. The height of the fabricated oxide pattern ($1{\sim}3\;nm$) on SiC is similar to that of typically obtained on Si ($10^{15}{\sim}10^{17}\;cm^{-3}$). We perform the 2-D simulation to further analyze the electric field between the tip and the surface. Whereas the simulated electric field on Si surface is constant ($5\;{\times}\;10^7\;V/m$), the electric field on SiC surface increases with increasing the doping concentration from ${\sim}10^{15}$ to ${\sim}10^{17}\;cm^{-3}$. We demonstrated that a specific electric field ($4\;{\times}\;10^7\;V/m$) and a doping concentration (${\sim}10^{17}\;cm^{-3}$) is sufficient to switch on/off the growth of the local oxide on SiC.

• 항공우주시스템공학회지
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• 제13권1호
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• pp.47-53
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• 2019

한국항공우주연구원(KARI)은 전기추진 수직이착륙(eVOTL) 항공기 공력성능 향상 방안 연구의 일환으로 교차회전 방식에 대한 기술개발 타탕성에 관한 연구를 진행하였다. 프로펠러 반지름을 증가시켜 전산해석을 수행하고 기존 상용 멀티콥터를 구매하여 0.11 m와 0.21 m 프로펠러를 적용하여 교차회전 구동방식에 관한 기술개발 가능성을 확인한 후, 총 중량 3 kg급의 멀티콥터를 설계 제작하여 추력 및 소음을 측정하기 위한 지상시험을 수행하였다. 교차회전 방식의 효율성을 검증하기 위해 지상시험은 15 in.와 22 in. 프로펠러를 적용하여 동일한 깃끝 속도(Tip speed) 조건에서 추력 및 소음을 측정하여 결과를 비교 분석 하였다. 지상시험결과 요구동력은 22 in. 프로펠러를 적용한 교차회전 방식이 15 in. 프로펠러와 비교하여 약 30%정도 절감 되며 공력소음의 경우 3~5 dB의 소음감소 효과가 측정 되었다.

• 한국의류학회지
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• 제36권1호
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• pp.12-26
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• 2012

Young people have got to like 'party' and 'attending parties' is considered 'reflection of trendy lifestyle' nowadays. The more party experiences they have, the more party wear styles get various and detail. They want different styles for the next party and it stimulates designers to create something new. We now realize that the party has become popular with an increased market demand for party wear. In addition, we analyze dress styles according to party types to suggest a new dress style to satisfy consumer needs. We suggest two ways to research party wear industry conditions in Korea. Off-line shop managers need to offer practical and various designs for a good price according to party types that make distinctions between on-line and off-line shops. On-line shop managers need to use better materials and develop better service. Considering an analysis of dress style according to party types, an elegant style is good for a formal dinner party and an evening party. A romantic style is good for a season party (such as a New Year's party, a Valentines party and a Christmas party) and a chic style is good for a music party (such as a classic party, jazz party and pop-era party). In addition, the result of a dress style analysis according to party types can be used for the tip for the development of designs to come in the party wear market as well as for a dress style guide to the partiers.

• 한국응용곤충학회지
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• 제40권1호
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• pp.15-21
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• 2001

여섯줄 위축선충속에 1신종 Geocenamus seonunensisn. sp.과 1미기록종 Geocenamus processus (Siddiqi, 1979) Brzeski, 1991를 새로히 채집하였다; Geocenamus seonunensis n. sp.는 G. myungsugae Choi & Geraert, 1993와 비슷하나 구순부가 단추모양이 아니고, 구침 길이가 56~67$\mu$m 으로 훨씬 긴 점이 다르다. G. tumensis(Skwiercz, 1984)Brzeski, 1991와는 둥근 수정낭을 가지고, 구침이 훨씬 긴 것이 다르고, G. superbus(Allen, 1955) Fortuner & Luc, 1990와는 꼬리 끝이 주름 진 것이 다르고, G. brevicaudatus(Peng & Hunt, 1995) Brzeski, 1998와는 구침이 긴 것이 다르고, G. longes (Wu, 1969) Tarjan, 1973. 와는 표피의 종주선의 수가 적은 것이 다르다.