• Bulletin of the Korean Mathematical Society
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• v.59 no.4
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• pp.961-977
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• 2022

In this paper, we consider the following Kirchhoff type equation on the whole space $$\{-(a+b{\displaystyle\smashmargin{2}{\int\nolimits_{{\mathbb{R}}^3}}}\;{\mid}{\nabla}u{\mid}^2dx){\Delta}u=u^5+{\lambda}k(x)g(u),\;x{\in}{\mathbb{R}}^3,\\u{\in}{\mathcal{D}}^{1,2}({\mathbb{R}}^3),$$ where λ > 0 is a real number and k, g satisfy some conditions. We mainly investigate the existence of ground state solution via variational method and concentration-compactness principle.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.11
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• pp.77-83
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• 2010

This paper presents the dual resonance PIFA(Planar Inverted F-Antenna) which satisfies the requirements of the 802.11n standard at both 2.4 GHz and 5 GHz frequency bands. Patch for 2.4 GHz and U-Type slot for 5 GHz were used for dual resonance, respectively. In this paper, the characteristics of an antenna were investigated by varying locations of short plate and feed point, the width of the short plate, the thickness and the location of U-Type slot. To investigate the characteristics of the PIFA, HFSS(High Frequency Structure Simulation) for the simulation was used. And the measurement results of a fabricated PIFA were compared with the simulated ones. The measurement and simulation results show that good dual resonance characteristics as the thickness of U-type slot decreases and when the location of U-type slot is far from the feed point.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1675-1680
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• 2011

Inductive power transfer module(IPTM) is a contact-less power supply device and its application range has been extended to the large capacity devices such as electric vehicles, industrial mover and railway system as well as small capacity devices such as electric toothbrush charger, celluar phone charger, and so on. For railway application, the IPTM will transfer energy while train stops at a station for around 30[sec]. Therefore, equivalent circuit parameters and coupling coefficient of IPTM are an important design factor for the high energy transfer efficiency. This paper investigates the properties of equivalent circuit parameters and coupling coefficient of U-U type IPTM and U-I type IPTM using an analytical method and experimental method. Considering the coupling coefficient of the U-U type is larger than U-I type's, the U-U type is suitable for an application which need maximum power transfer and high efficiency.

• Journal of the Korean Institute of Educational Facilities
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• v.10 no.2
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• pp.15-22
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• 2003

The purpose of this study is to find problems and to provide architectural design standards of the Learning Space Unit(L.S.U.) in Elementary Schools through the Post-occupancy Evaluation(POE). In this study, we found six major problems of the type of the L.S.U. in elementary schools. More than 50% of users expressed dissatisfactions in these items : size, safety, cooling facility, noise, privacy and primary meaning for its original purpose. After the interrelation-analysis, we checked pros and cons about each forms of L.S.U. It is the result of analysis of the layout method in L.S.U. 1) "$8.4m{\times}8.4m$" classroom unit got the highest positive responses 2) "2-classroom type" and "4-classroom type" got higher score than "3-classroom type" 3) "Whole faced type" 1) made more active Multi-space than "Partial faced type" 4) prefered prepared "Open-classroom" to "Closed-classroom" 5) 'Zoning type between L.S.U.s' couldn't influence to user's responses. Designers can consult those informations when they plan a new, remodeling and additional elementary school.

• Nuclear Engineering and Technology
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• v.33 no.3
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• pp.307-314
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• 2001

The changes of weight gain, structure, morphology and uranium oxidation states in l0wt% G $d_2$ $O_3$-doped U $O_2$ during the oxidation below 475$^{\circ}C$ and heat treatment at 130$0^{\circ}C$ in air were investigated using TGA, XRD, SEM, EPMA and XPS. The room temperature ( $U_{0.86}$G $d_{0.14}$) $O_2$Cubic Phase Converted to highly distorted ( $U_{0.86}$G $d_{0.14}$)$_3$ $O_{8}$ -type sing1e Phase by oxidation at 475 $^{\circ}C$ in air. This oxidized phase was reduced by annealing at 130$0^{\circ}C$ in air. The room temperature XRD pattern of the 130$0^{\circ}C$ annealed powder revealed that ( $U_{0.86}$G $d_{0.14}$)$_3$ $O_{8}$ -type single phase was separated into Gd-depleted $U_3$ $O_{8}$ and Gd-enriched ( $U_{0.7}$G $d_{0.3}$) $O_2$$_{+x}$ type cubic phase. The reduction and phase separation by the high temperature annealing of kinetically metastable and highly deformed ( $U_{0.86}$G $d_{0.14}$)$_3$ $O_{8}$ -type phase are interpreted in terms of cation size difference between G $d^3$$^{+}$ and U according to the oxidation state of U.U.U.U.U.te of U.U.U.U.U.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.361-362
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• 2006

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.763-764
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• 2008

• Journal of the Korean Mathematical Society
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• v.44 no.5
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• pp.1065-1078
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• 2007

We consider initial value problems for the semirelativistic Hartree type equations with cubic convolution nonlinearity $F(u)=(V*{\mid}u{\mid}^2)u$. Here V is a sum of two Coulomb type potentials. Under a specified decay condition and a symmetric condition for the potential V we show the global existence and scattering of solutions.

• East Asian mathematical journal
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• v.38 no.1
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• pp.13-20
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• 2022

We establish multiplicity results for positive solutions to the Schrödinger-type singular positone problem: -∆u + V (x)u = λf(u) in Ω, u = 0 on ∂Ω, where Ω is a bounded domain in ℝ^N, N > 2, λ is a positive parameter, V ∈ L^∞(Ω) and f : [0, ∞) → (0, ∞) is a continuous function. In particular, when f is sublinear at infinity we discuss the existence of at least three positive solutions for a certain range of λ. The proofs are mainly based on the sub- and supersolution method.

• Journal of Power System Engineering
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• v.13 no.6
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• pp.117-122
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• 2009

The wedge type rail clamp compresses the rails with small clamping force at first, and with large clamping force when the wind speed increases because of the wedge working. If the supporter is not installed in the rail clamp with V-type wedge when the wind speed increases more and more, the structure will occur overload which leads the structure to fracture. But in the clamp with U-type wedge the supporter is not necessary because the tangential angle of the wedge increases as the sliding distance increases. The proper shape of U-type wedge is determined by the initial clamping force and the tangential angle of the wedge. Accordingly we, first carry out the finite element analysis in order to analyze the relation between the sliding distance and the wedge angle. Next we suggest the proper shape of U-type wedge as analyze the relation between the radius of curvature and the sliding distance.