• Transactions of the Korean hydrogen and new energy society
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• v.21 no.6
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• pp.540-546
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• 2010

In order to confirm the effect of Nafion ionomer content in catalyst layer on the performance of PEMFC, we have fabricated several electrodes which were prepared by varying the quantity of Nafion ionomer from 24 wt.% to 39 wt.% in catalyst layer. The effect of Nafion ionomer of each electrode was evaluated with cyclic voltammetry measurement. In addition, cell performance was obtained through single cell test using hydrogen and air. The Pt utilization and performance of single cell were changed by addition of Nafion ionomer to the electrode. Single cell fabricated with 33 wt.% of Nafion ionomer in catalyst layer showed the maximum Pt utilization and performance.

• Journal of Korea Multimedia Society
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• v.6 no.7
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• pp.1312-1320
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• 2003

In this paper, we consider a multilayer neural network, with a single hidden layer. Error backpropagation learning method used widely in multilayer neural networks has a possibility of local minima due to the inadequate weights and the insufficient number of hidden nodes. So we propose a fuzzy supervised learning algorithm by using self-generation that self-generates hidden nodes by the compound fuzzy single layer perceptron and modified ART1. From the input layer to hidden layer, a modified ART1 is used to produce nodes. And winner take-all method is adopted to the connection weight adaptation, so that a stored pattern for some pattern gets updated. The proposed method has applied to the student identification card images. In simulation results, the proposed method reduces a possibility of local minima and improves learning speed and paralysis than the conventional error backpropagation learning algorithm.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.344-349
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• 2005

This paper is studied on the effect of TiAlN coated ball end mill on cutting characteristic of high hardness steels in dry cutting condition without coolant. KP4 steels[HRC32] and STD11[HRC60] heat treated steels wert: used as the workpiece and WC-Co ball end mill and single and multi layer TiAlN coated ball end mill were utilized. Results showed that TiAlN coated ball end mill were increased the cutting length than WC-Co ball end mill in the cutting speed$[245\~320m/min]$ about $2\~5$ times for KP4 steels and about $2.7\~4.3$ times for STD11 heat treated steels. The multi layer TiAlN coated ball end mill is good about $1.2\~1.7$ times for KP4 steels and STD11 steels than single layer coated.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.9
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• pp.878-882
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• 2006

We have fabricated single organic layer devices of the organolanthanide complex, terbium tris-(1-phenyl-3-methyl-4-(tertiarybutyry)pyrazol-5-one)triphenylphosphine oxide [$(tb-PMP)_{3}Tb-(Ph_{3}PO)$] for the investigation of its light emission and electrical conduction properties. The thickness of ($(tb-PMP)_{3}Tb-(Ph_{3}PO)$) layer was varied to 60, 75, 95 nm. Mg and Ca layers were used for the cathode contact. The electrical conduction in the $(tb-PMP)_{3}Tb-(Ph_{3}PO)$ single layer devices was dominated by the injection of electrons into the organic layer from the cathode. A higher current density at much lower voltages can be attained with Ca cathode because of the enhanced electron injection. The device shows very sharp emission at 548 nm. The FWHM of the strongest emission peak was 12 nm.

• Journal of Environmental Science International
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• v.21 no.3
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• pp.305-312
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• 2012

This work is to study the variations of adsorption characteristics of binary vapor according to packing system of double-layer bed by fixed bed experiment. Breakthrough curves of single and binary vapor composed of acetone and benzene on single-layer and double-layer adsorption bed composed of activated carbon (AC) and silica-aluminar (SA) were compared. Adsorptions of binary vapor on double-layer bed were influenced by the differences of surface area between adsorbents as well as the polarity difference between adsorbent and adsorbate. The roll-up phenomenon of acetone vapor was happened by replacement with competing adsorption between acetone vapor and benzene vapor on AC bed, but it was not happened on SA bed because acetone vapor and benzene vapor had less difference in affinity with SA bed. The breakthrough times of acetone vapor and benzene vapor on AC/SA double-layer bed were three times and 1.4 times larger respectively than on SA/AC double-layer bed, the differences of breakthrough times were relatively larger than the equilibrium adsorption capacities according to packing system of double-layer bed.

• Tribology and Lubricants
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• v.35 no.4
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• pp.199-205
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• 2019

Two-dimensional materials such as graphene, h-BN, and $MoS_2$ have attracted increased interest as solid lubricant and protective coating layer for nanoscale devices owing to their superior mechanical properties and low friction characteristics. In this work, the frictional properties of single-layer graphene, h-BN, and $MoS_2$ are experimentally investigated under various normal forces using atomic force microscope (AFM) tips with a spherical and flat end, with the aim to gain a better understanding of frictional behaviors. The nonlinear relationship between friction and normal force friction was clearly observed for single-layer graphene, h-BN, $MoS_2$ specimens slid against the spherical and flat AFM tips. The results also indicate that single-layer graphene, h-BN, $MoS_2$ exhibit low frictional properties (e.g., friction coefficient below 0.1 under 70~100 nN normal force). In particular, graphene is found to be superior to h-BN and $MoS_2$ in terms of frictional properties. However, the friction of single-layer graphene, h-BN, $MoS_2$ against the flat tip is larger than that against the spherical tip, which may be attributed to the relatively large adhesion. Furthermore, it is shown that the fluctuation of friction is more significant for the flat tip than the spherical tip. The resutls of this study may be helpful to elucidate the feasibility of using two-dimensional materials as solid lubricant and protective coating layer for nanoscale devices.

• Progress in Superconductivity and Cryogenics
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• v.8 no.4
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• pp.8-11
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• 2006

High temperature superconducting coated conductor has various buffer structures on Ni-W alloy. We comparatively studied the growth conditions of a multi buffer layer $(CeO_2/YSZ/CeO_2)$ and a single buffer layer$(CeO_2)$ on textured Ni-W alloy tapes. XRD data showed that the qualities of in-plane and out-of-plane textures of the two type buffer structures were good. Also, we investigated the properties of SmBCO superconducting layer that was deposited on the two type buffer structure. The SmBCO superconducting properties on the single and multi buffer structure showed different critical current values and surface morphologies. FWHM of In-plane and out-of-plane textures were $7.4^{\circ},\;5.0^{\circ}$ in the top CeO2 layer of the multi-buffer layers of $CeO_2/YSZ/CeO_2$, and $7.3^{\circ},\;5.1^{\circ}$ in the $CeO_2$ single buffer layer. $1{\mu}m-thick$ SmBCO superconducting layers were deposited on two type buffer layer. $I_c$ of SmBCO deposited on single and multi buffer were 90 A/cm, 150 A/cm and corresponding $J_c$ were $0.9MA/cm^2,\;1.5MA/cm^2$ at 77K in self-field, respectively.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.352-354
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• 2005

As further Studies on 4th generation mobile telecommunication are progressed, the importance of a Cross-Layer is being increased. However, it has focused on coordination model only between MAC layer and PHY layer. It is necessary to expand into II' layer and upper layers. In this paper, we introduce a Cross-layer optimization which can be used to transmit video data with effect by managing resources among layers. It can gives further more adaptive method to solve QoS model problem than single layer.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.178.1-178.1
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• 2015

In and Ga doped ZnO (IGZO) thin films were prepared by radio frequency magnetron sputtering without intentional substrate heating on glass substrate and TiO2-deposited glass substrates to consider the effect of a thin TiO2 buffer layer on the optical and electrical properties of the films. The thicknesses of the TiO2 buffer layer and IGZO films were kept constant at 5 and 100 nm, respectively. Since the IGZO/TiO2 bi-layered films show the higher FOM value than that of the IGZO single layer films, it is supposed that the IGZO/TiO2 bi-layered films will likely perform better in TCO applications than IGZO single layer films.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.178.2-178.2
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• 2015

In and Ga doped ZnO (IGZO) films were deposited on 5 nm thick Cu film buffered Polycarbonate (PC) substrates with RF magnetron sputtering and then the effect of Cu buffer layer on the optical and electrical properties of the films was investigated. While IGZO single layer films show the electrical resistivity of $1.2{\times}10-1{\Omega}cm$, IGZO/Cu bi-layered films show a lower resistivity of $1.6{\times}10-3{\Omega}cm$. Although the optical transmittance of the films in a visible wave length range is deteriorated by Cu buffer layer, IGZO films with 5 nm thick Cu buffer layer show the higher figure of merit of $2.6{\times}10-4{\Omega}-1$ than that of the IGZO single layer films due to the enhanced opto-electrical performance of the IGZO/Cu bi-layered films.