• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집C
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• pp.408-413
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• 2001

The structural optimization is carried out in the continuous design space or discrete design space. Methods for discrete variables such as genetic algorithms are extremely expensive in computational cost. In this research, an iterative optimization algorithm using orthogonal arrays is developed for design in discrete space. An orthogonal array is selected on a discrete design space and levels are selected from candidate values. Matrix experiments with the orthogonal array are conducted. New results of matrix experiments are obtained with penalty functions for constraints. A new design is determined from analysis of means(ANOM). An orthogonal array is defined around the new values and matrix experiments are conducted. The final optimum design is found from iterative process. The suggested algorithm has been applied to various problems such as truss and frame type structures. The results are compared with those from a genetic algorithm and discussed.

• 한국진공학회지
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• 제10권1호
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• pp.57-60
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• 2001

우리는 술폭시화디메틸에 $_CdCl2$와 S를 포함하는 전해질로부터 양극산화된 알루미나 막의 세공 안으로 반도체를 직접 전착하여 5$\mu\textrm{m}$까지의 길이와 20nm의 작은 직경의 균등한 CdS 나노선 배열을 제조하였다. 나노선 배열은 주사전자현미경법과 X-선회절에 의해 연구되었다. 전착된 물질은 주로 (100) 우선방위를 지닌 육방정계 CdS로 이루어져 있다.

• 한국정밀공학회지
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• 제17권6호
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• pp.69-75
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• 2000

At the stage of initial design, prototypes are needed for engineering and aesthetic purposes. In order to get a fast and non-expensive prototype, designers prefer rapid prototyping(RP) to any other means. In driving a 3D CAD model into rapid prototyping, sectioning the model is essential and there are two negotiation-needed targets, enhancing accuracy while taking less build-time, which makes adaptive slicing taken into account. In spite of the advantages of adaptive slicing, it is not yet applied to real RP machines because of the limits of hardwares. In this thesis, a new slicing algorithm which (1)uses several values of thickness available in a RP machine. (2)determines total number of layers to make the prototype within the intended time and (3)arranges the layers using orthogonal arrays to minimize the volume error caused by the difference between a given CAD model and a fabricated model is presented. And the algorithm is expected to have possibility of assisting RP machines to take the advantages of adaptive slicing.

• Transactions on Electrical and Electronic Materials
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• 제14권1호
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• pp.28-31
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• 2013

A volcano shaped gated Si-FEA (silicon field emitter array) was simply fabricated using sputtering as a gate electrode deposition and lift-off for the removal of the oxide mask, respectively. Due to the limited step coverage of well-controlled sputtering and the high aspect ratio in Si dry etch caused by high RF power, it was possible to obtain Si FEAs with a stable volcano shaped gate structure and to realize the restriction of gate leakage current in field emission characteristics. For 100 tip arrays and 625 tip arrays, gate leakage currents were restricted to less than 1% of the anode current in spite of the volcano-shaped gate structure. It was also possible to keep the emitters stable without any failure between the Si cathode and gate electrode in field emission for a long time.

• 대한수학회지
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• 제46권4호
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• pp.827-840
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• 2009

Let {$X_{ni}$ | $1{\leq}i{\leq}n,\;n{\geq}1$} be an array of rowwise negatively dependent (ND) random variables. We in this paper discuss the conditions of ${\sum}^n_{t=1}a_{ni}X_{ni}{\rightarrow}0$ completely as $n{\rightarrow}{\infty}$ under not necessarily identically distributed setting and the strong law of large numbers for weighted sums of arrays of rowwise negatively dependent random variables is also considered.

• 품질경영학회지
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• 제40권1호
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• pp.15-24
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• 2012

For the construction of fractional factorial designs, the various arrays can be widely used. In this paper we review the statistical properties of fractional designs constructed by two arrays such as orthogonal array and partially balanced array, and develop a quick and easy method for analyzing unreplicated saturated designs. The proposed method can be characterized that we control the error rate by experiment-wise way and exploit the multivariate Student $t$-distribution. Especially the proposed method can be used efficiently together with some exploratory analysis methods, such as half normal probability plot method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1529_1530
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• 2009

The process conditions for fabricating p-type silicon pillars were optimized by controlling current density, bath temperature. To get best process flexibility for pillar arrays formation, three factors affecting pillar formation were changed. First, the solution bath was designed to keep constant temperature during the experiment irrespective of external temperature. Second, the counter Pt electrode was changed from rod type to mesh to obtain uniform distribution of current density. Third, Cr-Cu alloy electrode instead of Cu was used to increase electrode current density.

• International Journal of Aeronautical and Space Sciences
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• 제18권2호
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• pp.245-254
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• 2017

In this paper, deployment dynamics of large-scale flexible solar arrays with deployable mast is investigated. The adopted solar array system is introduced firstly, then kinematic description and kinematic constraint equations are deduced, and finally, dynamics equation of the system is established by the Jourdain velocity variation principle and a new method to deal with topology changes of the deployable mast is introduced. The dynamic behavior of the system is studied in detail. Simulation results indicate that the proposed model is effective to describe the deployment dynamics of the solar arrays and that the introduced method is applicable for topology changes.

• 한국분말재료학회지
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• 제22권3호
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• pp.216-220
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• 2015

Vertically oriented nickel nanowire arrays with a different diameter and length are synthesized in porous anodic aluminium oxide templates by an electrodeposition method. The pore diameters of the templates are adjusted by controlling the anodization conditions and then they are utilized as templates to grow nickel nanowire arrays. The nickel nanowires have the average diameters of approximately 25 and 260 nm and the crystal structure, morphology and microstructure of the nanowires are systematically investigated using XRD, FE-SEM and TEM analysis. The nickel nanowire arrays show a magnetic anisotropy with the easy axis parallel to the nanowires and the coercivity and remanence enhance with decreasing a wire diameter and increasing a wire length.

• 통합자연과학논문집
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• 제6권3호
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• pp.170-175
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• 2013

Silicon nanowires were detached and obtained from silicon nanowire arrays on silicon substrate using a ultrasono-method. Silicon nanowire arrays on silicon substrate were prepared with an electroless metal assisted etching of p-type silicon. The etching solution was an aqueous HF solution containing silver nitrate. SEM observation shows that well-aligned nanowire arrays perpendicular to the surface of the silicon substrate were produced. After sonication of silicon nanowire array, an individual silicon nanowire was confirmed by FESEM. Optical characteristics of SiNWs were measured by FT-IR spectroscopy. The surface of SiNWs are terminated with hydrogen.