• 한국수소및신에너지학회논문집
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• 제20권6호
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• pp.485-491
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• 2009

In present work, NiO/YSZ anode functional layer was prepared by nano NiO powder and 8YSZ powder. The nano NiO powders were made by Pulsed wire evaporation (PWE) method. Nano NiO- YSZ functional layer was sintered at the temperature of $900-1400^{\circ}C$. The prepared functional layer was characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy. The nano NiO- YSZ anode functional layer sintered at $1300^{\circ}C$ shows the lowest polarization resistance. Nano NiO- YSZ anode functional layer shows about two times smaller polarization resistance than the anode functional layer made by commercial NiO-YSZ powders. Based on these experimental results, it is concluded that the nano NiO-YSZ cermet is suitable as a anode functional layer operated at $800^{\circ}C$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.571-574
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• 2003

The thin films fabricated by using the layer-by-layer sputtering was compared with the thin film fabricated by using the evaporation method. Re-evaporation in the form of Bi atoms or $Bi_2O_3$ molecules easily bring out the deficiency of Bi atoms in thin film due to the long sputtering time of the layer-by-layer deposition. On the other hand, the respective atom numbers corresponding to BiSrCaCuO phase is concurrently supplied on the film surface in the evaporation deposition process and leads to BiSrCaCuO phase formation. Also, it is cofirmed that by optimizing the deposition condition, each single phase of the Bi2201 phase and the Bi2212 phase can be fabricated, the sticking coefficient of Bi element is clearly related to the changing of substrate temperature and the formation of the Bi2212 phase.

• 한국콘텐츠학회논문지
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• 제7권10호
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• pp.1-9
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• 2007

한정된 자원을 다수의 사용자에게 분배해야 하는 무선 네트워크의 환경에서 자원의 할당과 관리는 중요하다. 이를 위해 다른 레이어 간에 통합 적응하는 레이어를 디자인해야 하는 필요성이 대두되고 있다. 본 논문에서는 크로스 레이어 기반의 스케줄링 기법에 대해 다룬다. 기존의 스케줄링 기법들 살펴보고 이를 보완한 스케줄링 기법을 제시한다. 멀티미디어 서비스 환경에서는 다양한 서비스를 제공하기 때문에 스케줄링 기법 또한 다양하게 적용할 수 있어야 한다. 따라서 기존 기법에서 적용되지 않았던 서비스에 따른 스케줄링 기법을 제시하였다. 제시한 기법은 시뮬레이션을 통해 기존의 기법에 비해 무선자원 이용효율이 뛰어남을 보였다.

• Geomechanics and Engineering
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• 제3권2호
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• pp.117-130
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• 2011

The methods of design available for geocell-supported embankments are very few. Two of the earlier methods are considered in this paper and a third method is proposed and compared with them. In the first method called slip line method, plastic bearing failure of the soil was assumed and the additional resistance due to geocell layer is calculated using a non-symmetric slip line field in the soft foundation soil. In the second method based on slope stability analysis, general-purpose slope stability program was used to design the geocell mattress of required strength for embankment. In the third method proposed in this paper, geocell reinforcement is designed based on the plane strain finite element analysis of embankments. The geocell layer is modelled as an equivalent composite layer with modified strength and stiffness values. The strength and dimensions of geocell layer is estimated for the required bearing capacity or permissible deformations. These three design methods are compared through a design example. It is observed that the design method based on finite element simulations is most comprehensive because it addresses the issue of permissible deformations and also gives complete stress, deformation and strain behaviour of the embankment under given loading conditions.

• Advances in Computational Design
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• 제9권2호
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• pp.115-136
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• 2024

Stochastic optimization methods have been extensively studied for structural optimization in recent decades. In this study, a novel algorithm named the CA-SA method, is proposed for topology optimization of steel double-layer grid structures. The CA-SA method is a hybridized algorithm combining the Simulated Annealing (SA) algorithm and the Cellular Automata (CA) method. In the CA-SA method, during the initial iterations of the SA algorithm, some of the preliminary designs obtained by SA are placed in the cells of the CA. In each successive iteration, a cell is randomly chosen from the CA. Then, the "local leader" (LL) is determined by selecting the best design from the chosen cell and its neighboring ones. This LL then serves as the leader for modifying the SA algorithm. To evaluate the performance of the proposed CA-SA algorithm, two square-on-square steel double-layer grid structures are considered, with discrete cross-sectional areas. These numerical examples demonstrate the superiority of the CA-SA method over SA, and other meta-heuristic algorithms reported in the literature in the topology optimization of large-scale skeletal structures.

• ETRI Journal
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• 제28권6호
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• pp.709-720
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• 2006

In this paper, we suggest a simple and efficient multiple-forwarder-based file distribution method which can work with a tree-based application layer multicast. Existing multiple-forwarder approaches require high control overhead. The proposed method exploits the assumption that receivers join a session at different times. In tree-based application layer multicast, a set of data packets is delivered from its parent after a receiver has joined but before the next receiver joins without overlapping that of other receivers. The proposed method selects forwarders from among the preceding receivers and the forwarder forwards data packets from the non-overlapping data packet set. Three variations of forwarder selection algorithms are proposed. The impact of the proposed algorithms is evaluated using numerical analysis. A performance evaluation using PlanetLab, a global area overlay testbed, shows that the proposed method enhances throughput while maintaining the data packet duplication ratio and control overhead significantly lower than the existing method, Bullet.

• 반도체디스플레이기술학회지
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• 제2권4호
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• pp.27-30
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• 2003

The effect of fabrication method of catalytic layer on electrode performance has been investigated. Brush, spray gun and screen printer were used as fabrication tool and catalytic layers were formed by several methods in screen printing. Direct screen printing on polymer membrane, screen printing on carbon paper, and their combined method were applied. In the electrode fabricated by the screen printing method, Pt loading of Pt/C catalysts could be cut down to 50%, compared with results by the brushing and spraying methods. The best result of electrode was obtained as 0.6 V, at 1 A/$\textrm{cm}^2$ when catalytic layer was formed by the combined way.

• International Journal of Ocean System Engineering
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• 제3권3호
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• pp.111-115
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• 2013

Blasius equation describes the boundary layer formed over a flat plate inside a fluid and this equation is solved numerically by the method of moments which is a type of weighted residual methods. Compared to the traditionally used Runge - Kutta Method, Method of Moments propose a direct solution to Blasius Equation which makes it easier to solve. The obtained solutions show good agreement with the results found in literature and this study aims to demonstrate the power of the method.

• International Journal of Naval Architecture and Ocean Engineering
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• 제11권1호
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• pp.510-520
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• 2019

To investigate the morphology characteristics of air layer in the air cavity, a numerical method with the combination of RANS equations and VOF two-phase-flow model is proposed for a plate with air cavity. Based on the model above, the dynamic and developmental process of air layer in the air cavity is studied. Numerical results indicate that the air layer in the plate's air cavity exhibits the dynamic state of morphology and the wavelength of air layer becomes larger with the increasing speed. The morphology of air layer agrees with the Froude similarity law and the formation of the air layer is not affected by the parameters of the cavity, however, the wave pattern of the air layer is influenced by the parameters of the cavity. The stable air layer under the air cavity is important for the resistance reduction for the air layer drag reduction.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.413-413
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• 2014

In this paper, we present a fabrication method of functionalized gold nanostructures on flexible substrate that can be implemented for plasmonic sensing application. For biomolecular sensing, many researchers exploit unconventional lithography method like nanoimprint lithography (NIP), contact transfer lithography, soft lithography, colloidal transfer printing due to its usability and easy to functionalization. In particular, nanoimprint and contact transfer lithography need to have anti-adhesion layer for distinctive metallic properties on the flexible substrates. However, when metallic thin film was deposited on the anti-adhesion layer coated substrates, we discover much aggravation of the mold by repetitive use. Thus it would be impossible to get a high quality of metal nanostructure on the transferred substrate for developing flexible electronics based transfer printing. Here we demonstrate a method for nano-pillar mold and transfer the controllable nanoparticle array on the flexible substrates without an anti-adhesion layer. Also functionalization of gold was investigated by the different length of thiol applied for effectively localized surface plasmonic resonance sensing. First, a focused ion beam (FIB) and ICP-RIE are used to fabricate the nanoscale pillar array. Then gold metal layer is deposited onto the patterned nanostructure. The metallic 130 nm and 250 nm nanodisk pattern are transferred onto flexible polymer substrate by bi-layer functionalized contact imprinting which can be tunable surface energy interfaces. Different thiol reagents such as Thioglycolic acid (98%), 3-Mercaptopropionic acid (99%), 11-Mercaptoundecanoic acid (95%) and 16-Mercaptohexadecanoic acid (90%) are used. Overcoming the repeatedly usage of the anti-adhesion layer mold which has less uniformity and not washable interface, contact printing method using bi-layer gold array are not only expedient access to fabrication but also have distinctive properties including anti-adhesion layer free, functionalized bottom of the gold nano disk, repeatedly replicate the pattern on the flexible substrate. As a result we demonstrate the feasibility of flexible plasmonic sensing interface and anticipate that the method can be extended to variable application including the portable bio sensor via mass production of stable nanostructure array and other nanophotonic application.