• Transactions on Electrical and Electronic Materials
• /
• v.14 no.3
• /
• pp.133-138
• /
• 2013

Acrylonitrile-butadiene-styrene (ABS) plastic is a polymer material extensively used in electrical and electronic applications. Nickel (Ni) thin film was deposited on ABS by electroless plating, after its surface was treated and modified with atmospheric plasma generated by means of dielectric barrier discharges (DBDs) in air. The method in this study was developed as a pre-treatment for electroless plating using DBDs, and is a dry process featuring fewer processing steps and more environmentally friendliness than the chemical method. After ABS surfaces were modified, surface morphologies were observed using a scanning electron microscope (SEM) to check for any physical changes of the surfaces. Cross-sectional SEM images were taken to observe the binding characteristics between metallic films and ABS after metal plating. According to the SEM images, the depths of ABS by plasma are shallow compared to those modified by chemically treatment. The static contact angles were measured with deionized (DI) water droplets on the modified surfaces in order to observe for any changes in chemical activities and wettability. The surfaces modified by plasma showed smaller contact angles, and their modified states lasted longer than those modified by chemical etching. Adhesion strengths were measured using 3M tape (3M 810D standard) and by 90° peel-off tests. The peel-off test revealed the stronger adhesion of the Ni films on the plasma-modified surfaces than on the chemically modified surfaces. Thermal shock test was performed by changing the temperature drastically to see if any detachment of Ni film from ABS would occur due to the differences in thermal expansion coefficients between them. Only for the plasma-treated samples showed no separation of the Ni films from the ABS surfaces in tests. The adhesion strengths of metallic films on the ABS processed by the method developed in this study are better than those of the chemically processed films.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.08a
• /
• pp.234-234
• /
• 2010

The PR transitions in asymmetric dot-in-double-quantum-well (DdWELL) photodetector is identified by bias-dependent spectral behaviors. Discrete n-i-n infrared photodetectors were fabricated on a 30-period asymmetric InAs-QD/[InGaAs/GaAs]/AlGaAs DdWELL wafer that was prepared by MBE technique. A 2.0-monolayer (ML) InAs QD ensemble was embedded in upper combined well of InGaAs/GaAs and each stack is separated by a 50-nm AlGaAs barrier. Each pixel has circular aperture of 300 um in diameter, and the mesa cell ($410{\times}410\;{\mu}m^2$) was defined by shallow etching. PR measurements were performed in the spectral range of $3{\sim}13\;{\mu}m$ (~ 100-400 meV) by using a Fourier-transform infrared (FTIR) spectrometer and a low-noise preamplifier. The asymmetric photodetector exhibits unique transition behaviors that near-/far-infrared (NIR/FIR) photoresponse (PR) bands are blue/red shifted by the electric field, contrasted to mid-infrared (MIR) with no dependence. In addition, the MIR-FIR dual-band spectra change into single-band feature by the polarity. A four-level energy band model is proposed for the transition scheme, and the field dependence of FIR bands numerically calculated by a simplified DdWELL structure is in good agreement with that of the PR spectra. The wavelength shift by the field strength and the spectral change by the polarity are discussed on the basis of four-level transition.

• Journal of Surface Science and Engineering
• /
• v.53 no.3
• /
• pp.116-123
• /
• 2020

Ion beam irradiation induces self-organization of nanostructure on the surface of polymer film. We show that the incident angle of Ar ions on polyethylene naphthalate(PEN) film changes self-organized nanostructure. PEN film was irradiated by argon ion beams with the ion incident angle of 0°, 30°, 45°, 60°, and 80°. Nanostructure was altered from dimple to ripple structure as the angle increases. The ripple structure changed to pillar structure after 60°due to that the shallow incident angle increased the ion energy transfer per depth up to 50 eV/Å, which value could induce excessive surface heating and oligomer formation reacting as a physical mask for anisotropic etching. And quantitative analysis of the nanostructures was adapted by using ABC model and fractal dimension theory.

• Journal of the Korean Geotechnical Society
• /
• v.17 no.4
• /
• pp.289-299
• /
• 2001

본 연구는 균질 및 2개층 비균질지반에서 사질토지반 상에 놓인 정방형 기초의 극한지지력과 침하에 대하여 고찰하였다. 본 연구는 얕은기초의 거동에 대한 정방형 기초의 크기, 지반 상대밀도, 기초 폭에 대한 상부층의 두께 비(H/B), 상부층 아래 경계면의 경사($\theta$) 그리고 지반강성비의 영향을 규명하기 위하여 모형실험을 수행하였다. 동일 상대밀도에서 지지력 계수($N_{{\gamma}}$)는 일정하지 않으며 기초 폭에 직접적으로 관련되며 지지력계수는 기초 폭이 증가함에 따라 감소하였다. 기초크기의 영향과 구속압력의 영향을 고려하는 Ueno 방법에 의한 극한지지력의 예측값은 고전적인 지지력 산정식보다 더 잘 일치하며 그 값은 실험값의 65% 이상으로 나타났다. $\theta$=$0^{\circ}$인 2개층 지반의 결과에 근거하여, 극한지지력에 대한 하부층 지반의 영향을 무시할 수 있는 한계 상부층 두께는 기초 폭의 2배로 결정되었다. 그러나, 73%의 상부층 상대밀도인 경우는 침하비($\delta$B) 0.05 이하에서만 이 결과가 유효하였다. 경계면이 경사진 2개층 지반의 결과에 근거하여, 상부층의 상대밀도가 느슨할수록 그리고 상부층의 두께가 클수록 극한지지력에 대한 경계면 경사의 영향은 크지 않는 것으로 나타났다. 경계면의 경사가 증가함에 따른 극한침하량의 변화는 경계면이 수평인 경우($\theta$=$0^{\circ}$)를 기준으로 0.82~1.2(상부층 $D_{r}$=73%인 경우) 그리고 0.9~1.07(상부층 $D_{r}$=50%인 경우) 정도로 나타났다.Markup Language 문서로부터 무선 마크업 언어 문서로 자동 변환된 텍스트를 인코딩하는 경우와 같이 특정한 응용 분야에서는 일반 문자열에 대한 확장 인코딩 기법을 적용할 필요가 있을 수 있다.mical etch-stop method for the etching of Si in TMAH:IPA;pyrazine solutions provides a powerful and versatile alternative process for fabricating high-yield Si micro-membranes. the RSC circle, but also to the logistics system in the SLC circle. Thus, the RSLC model can maximize combat synergy effects by integrating the RSC and the SLC. With a similar logic, this paper develops "A Revised System of Systems with Logistics (RSSL)" which combines "A New system of Systems" and logistics. These tow models proposed here help explain several issues such as logistics environment in future warfare, MOE(Measure of Effectiveness( on logistics performance, and COA(Course of Actions) for decreasing mass and increasing velocity. In particular, velocity in logistics is emphasized.