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        검색결과 3

        1.
        2019.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        정전기 문제에 대한 연속체 기반 설계 민감도 해석(DSA) 방법을 해석적으로 유도하였다. 고차 항을 포함한 목적 함수를 고려하기 위해 해석 및 DSA 방법을 위해 9 노드 유한요소법 기반 함수를 형상 함수로 사용하였다. 최적화 과정에서의 설계 변수를 B- 스플라인 함수로 매개 변수화하여 비현실적인 형상이 아닌 부드러운 경계를 가진 최적 형상을 얻을 수 있었다. 유한요소법을 이용한 최적화 과정에서 일반적으로 발생하는 메쉬 얽힘 문제를 해결하기 위해 메쉬 균일화 기법을 사용하였 다. 이 기법은 디리쉴릿 에너지 범함수를 최소화함으로써 메쉬 균일성을 자동으로 얻을 수 있게 한다. 몇 가지 수치 예제들 을 통해 DEP 힘을 최대화하기 위한 평행판의 최적 형상을 얻어낸다. 이를 기존에 실험적으로 검증된 평행판의 최적 형상과 비교하여 그 특성을 논의하였다.
        4,000원
        2.
        2015.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Anodic aluminum oxide (AAO) has been widely used for the development and fabrication of nano-powder with various morphologies such as particle, wire, rod, and tube. So far, many researchers have reported about shape control and fabrication of AAO films. However, they have reported on the shape control with different diameter and length of anodic aluminum oxide mainly. We present a combined mild-hard (or hard-mild) anodization to prepare shape-controlled AAO films. Two main parameters which are combination mild-hard (or hard-mild) anodization and run-time of voltage control are applied in this work. The voltages of mild and hard anodization are respectively 40 and 80 V. Anodization was conducted on the aluminum sheet in 0.3 mole oxalic acid at 4oC. AAO films with morphologies of varying interpore distance, branch-shaped pore, diameter-modulated pore and long funnel-shaped pore were fabricated. Those shapes will be able to apply to fabricate novel nano-materials with potential application which is especially a support to prevent volume expansion of inserted active materials, such as metal silicon or tin powder, in lithium ion battery. The silicon powder electrode using an AAO as a support shows outstanding cycle performance as 1003 mAh/g up to 200 cycles.
        4,000원
        3.
        2010.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper, the effect of electrical characteristics and electrode shape on the alignment and attachment of multi-walled carbon nanotubes (MWNTs) has been studied. The attraction and alignment of MWNTs between the gaps has been investigated by applying electric field which is called electrophoresis and dielectrophoresis. According to the frequency of electric field, positive or negative dielectrophoretic force can be determined. The concentration of MWNTs solution was , and a droplet of was dropped between two electrodes. Through the repeated experiments, the optimal electrical conditions for aligning and attaching MWNTs in the desired places were obtained. Since the frequency range of 100 kHz~10 MHz generated positive dielectrophoretic force, MWNTs were attracted and aligned between the gaps with this frequency range. For generating enough force to attract MWNTs, the appropriate voltage range was . Furthermore, the effect of electrode shape on the alignment of MWNTs was investigated. A single MWNT attachment was accomplished on the round shaped with 70% yield.
        4,000원