• 한국정보전자통신기술학회논문지
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• 제8권1호
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• pp.37-44
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• 2015

본 논문에서 전계효과 트랜지스터 (field effect transistor; FET) 제작을 위한 표면 프로그램된 aminopropylethoxysilane(APTES)와 1-octadecyltrichlorosilane(OTS) 패턴을 이용하여 단일벽 탄소 나노튜브(single-walled carbon nanotube; SWCNT)를 실리콘 기판 위에 선택적으로 흡착시키는 공정방법을 제안하였다. 양성 표면 분자 패턴을 만들기 위해 형성된 APTES 패턴은 많은 양의 SWCNT의 흡착을 위해 제작되었고, OTS 만을 이용한 공정보다 효과적인 SWCNT 흡착이 가능하다. 산화막(silicon dioxide)이 형성된 실리콘 기판 위에 사진공정(photolithography process)을 이용하여 임의의 감광액(photoresist; PR) 패턴이 형성되었다. PR 패턴이 형성된 기판은 헥산 용매를 이용하여 1:500 (v/v)로 희석된 OTS 용액 속에 담가진다. OTS 박막이 표면 전체에 만들어지고, PR 패턴이 제거되는 과정에서 PR 위에 형성되었던 OTS 박막도 같이 제거되어, 선택적으로 형성된 OTS 박막 패턴을 얻을 수 있다. 이 기판은 다시 에탄올 용매를 이용하여 희석된 APTES 용액 속에 담가진다. APTES 박막은 OTS 박막 패턴이 없는 노출된 산화막 위에 형성된다. 마지막으로 이처럼 APTES와 OTS에 의해 표면 프로그램된 기판은 SWCNT가 분산된 다이클로로벤젠(dichlorobenzene) 용액 속에 담가진다. 결과적으로 SWCNT는 양 극성을 띠는(positive charged) APTES 박막 패턴 위에만 흡착된다. 반면 중성O TS 박막 패턴 위에는흡착되지 않는다. 이러한 표면 프로그램 방법을 사용하여 SWCNT는 원하는 영역에 자기 조립시킬 수 있다. 우리는 이 방법을 이용하여 소오스와 드레인 전극사이에 SWCNT가 멀티 채널로 구성된 다중채널 FET를 성공적으로 제작하였다.

• 대한기계학회논문집
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• 제16권2호
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• pp.267-280
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• 1992

This paper describes a numerical analysis of the light scattering patterns of roughness profiles. This analysis was based upon the light scattering theory developed by Beckmann. In the analysis, the roughness profile was regarded as a profile whose irregularities depend on the production process and the shape of cutting tool. Generally, waviness of an actual surface seriously distorts the scattered pattern of roughness profile. In order to avoid the effects of waviness of actual surfaces, several theoretically calculated scattering patterns, instead of actual scattering patterns, were used to analyze the scattering patterns of typical engineering roughness profiles. The characteristics of the light scattering patterns for five model surfaces were studied.

• 한국의상디자인학회지
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• 제23권4호
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• pp.149-166
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• 2021

This study tried to suggest a drafting method to draft tight fit torso patterns suitable for adult males with a sway back somatotype and a bend forward somatotype by setting and distributing the ease through the completion of the somatic surface pattern using the 3D body surface segment method. It was intended to be presented as a drafting method. As for the research method, the suitability of the somatic surface patterns and the tight fit torso patterns were confirmed by the evaluation of virtual wear, and the patterns were modified and supplemented. The research results are as follows. In the first evaluation of the tight fit torso patterns, the average, for 55 evaluation items, was 3.92 points for the sway back somatotype and 3.89 points for the bend forward somatotype. In the second evaluation, the bend forward somatotype was 4.51 points and the sway back somatotype was 4.62 points. The chest circumference ease amount for the bend forward somatotype and the sway back somatotype are 6.5% (6.8 cm) and 7% (6.8 cm) of the chest circumference, respectively, and the distribution of the front and back ease is the same at 4:6 (2.72 cm:4.08 cm). The waist circumference ease amount is 6.5% (5.8cm) and 6.5% (5.6 cm) of the waist circumference dimensions, and the distribution of the front and backease are 5:5 (1.45 cm: 1.45 cm) and 4:6 (2.24 cm: 3.36 cm), respectively. The completed tight fit torso patterns were converted into institutional formulas and presented as a drafting method.

• Journal of Pharmaceutical Investigation
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• 제15권2호
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• pp.45-52
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• 1985

For the model tablets using mannitol and Avicel PH 101 as excipients, the patterns of disintegration and dissolution from the differences of physical properties were investigated. It was found that the patterns in the dissolution and binding forces in the interaction of materials by estimates of solid-solid or liquid surface free energy due to cohesive or adhesive properties of materials, and solid surface free energy in binding forces of tablet should be considered as an important factor in dissolution processes.

• 한국환경과학회지
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• 제10권6호
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• pp.437-444
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• 2001

The characteristic features of surface ozone concentration and the forecasting procedure of high ozone days have been studied. The ozone concentration was continuously measured during 3 years (1997~1999) at air quality monitoring stations in five major cities in Korea. The diurnal variation of surface ozone concentration on high ozone days is characterized by low ozone concentration at night. The ozone concentration Increases continuously after sunrise, In reach a peak at 1500~1600 LST. Thereafter it decreases steadily to a low concentration at sunset. The diurnal and annual maximum of the surface ozone concentration at Seoul were observed in May and June, respectively. The favorable synoptic condition for the high ozone day is divided into 4 different synoptic weather patterns: a high-pressure system from the Sea of Okhotsk, the Pacific subtropical high extending westward, a moving high-pressure system covering the Korean peninsula. and a synoptic system In front of a typhoon. Most of high ozone days occur under the high pressure system in Korea.

• Bulletin of the Korean Chemical Society
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• 제34권10호
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• pp.3141-3142
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• 2013

• Tribology and Lubricants
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• 제35권6호
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• pp.337-342
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• 2019

This paper presents an experimental investigation of friction and wear characteristic with respect to patterns occurring on the surface of 3D printed polymer products by fused deposition modeling method. The purpose of this study was to investigate the effect of the patterns and sliding directions on the tribological properties of 3D printed polymer surface. A cubic specimen was printed using polylactic acid filament as the printing material. Friction tests were conducted for different directions with respect to the patterns that were generated on the top and the side surfaces of the specimen, by using a ball-on-reciprocating type tribotester. SUJ2 bearing ball of which the diameter was 11 times greater than the width of the largest pattern was used as the counter surface to assess the frictional behavior. Friction tests were conducted on the top and the side surfaces with respect to the patterns in 3 (0°, 45°, 90°) different directions respectively. Coefficient of friction increased as cycles increased in all cases. The results of the tests showed that the lowest coefficient of friction was measured with the 45° sliding direction on the side surface. The wear rate was the lowest at 45° sliding direction on the side surface, while it was the highest at 0° sliding direction on the top surface. Coefficient of friction of about 0.45 was determined to be the converging value on the top compared to the side surface.

• 한국기계가공학회지
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• 제14권3호
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• pp.124-130
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• 2015

The purpose of this study is to investigate friction characteristics according to micro-dimple patterns. The surface texturing of micro-dimple patterns was tested to examine the friction of pin-on-disk using flat-on-flat contact geometry. The patterns of both dimple circle and groove pattern were adopted to carry out the effect of those ones. In the low loads, such as 13.8N and 27.7N, the friction coefficients of groove pattern were lower than those of dimple circle pattern. In many other comparisons of normal loads, the groove pattern had lower friction forces, which showed the effect of surface texturing. The relationship between sliding time and friction forces showed that the increase of friction forces of groove pattern were relatively lower than those of dimple pattern. In conclusion, the dimple patterns of dimple-circle pattern and groove pattern strongly contributed to reducing the friction between contacting materials.

• Current Applied Physics
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• 제18권11호
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• pp.1235-1239
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• 2018

We present a novel process to fabricate three-dimensional (3D) metallic patterns from 3D printed polymeric structures utilizing different hygroscopic swelling behavior of two different polymeric materials. 3D patterns are printed with two different polymers as cube shape. The surface of the 3D printed polymeric structures is plated with nickel by an electroless plating method. The nickel patterns on the surface of the 3D printed cube shape structure are formed by removing sacrificial layers using the difference in the rate of hygroscopic swelling between two printing polymer materials. The hygroscopic behavior on the interfaced structure was modeled with COMSOL Multiphysics. The surface and electrical properties of the fabricated three-dimensional patterns were analyzed and characterized.

• Journal of Advanced Research in Ocean Engineering
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• 제2권2호
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• pp.48-60
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• 2016

Accurate simulation of free-surface wave flows around a ship is very important for better hull-form design. In this paper, a computational fluid dynamics (CFD) code which is based on the open source libraries, OpenFOAM, was developed to predict the wave patterns around a ship. Additional anti-diffusion source term for minimizing a numerical diffusion, which was caused by convection differencing scheme, was considered in the volume-fraction transport equation. The influence of the anti-diffusion source term was tested by applying it to free-surface wave flow around the Wigley and KCS model ships. In results, the wave patterns and hull wave profiles of the Wigley and KCS model ships for various anti-diffusion coefficients showed quite close patterns. While, the band width of the water volume-fraction values between 0.1 to 0.9 at the Wigley and KCS model hull surfaces was narrowed by considering the anti-diffusion term. From the results, anti-diffusion source term decreased free-surface smearing.