• The Transactions of the Korean Institute of Electrical Engineers D
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• v.51 no.3
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• pp.96-99
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• 2002

We developed 1:1 resistance ratio measurement system for precision measurement of a series-resistor type dc voltage divider. By using active guard technique and exchange technique, any leakage effects, which are one of the most critical error sources, were successfully removed. The best measurement uncertainty with the developed ratio measurement system was estimated to be approximately $10^{-8}\;for\;10\;k{\Omega}\;and\;100\;k{\Omega}$.

• Journal of the Korean Mathematical Society
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• v.54 no.3
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• pp.1015-1030
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• 2017

This paper is concerned with the following Klein-Gordon-Maxwell system: $$\{-{\Delta}u+{\lambda}V(x)u-(2{\omega}+{\phi}){\phi}u=f(x,u),\;x{\in}\mathbb{R}^3,\\{\Delta}{\phi}=({\omega}+{\phi})u^2,\;x{\in}\mathbb{R}^3$$ where ${\omega}$ > 0 is a constant and ${\lambda}$ is the parameter. Under some suitable assumptions on V (x) and f(x, u), we establish the existence and multiplicity of nontrivial solutions of the above system via variational methods. Our conditions weaken the Ambrosetti Rabinowitz type condition.

• Journal of The Korean Astronomical Society
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• v.28 no.1
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• pp.61-65
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• 1995

We discuss a model4-dimensional Friedmann cosmology which may have evolved from a model of 4+D dimensions which admits spontaneous compactification of D dimensions (or N-dimensional variants of the Brans-Dicke (BD) theory). The BD parameter appearing in dimensional reduction is negative $-1<\omega<0$ (for the N-dimensional variants of the BD theory, $-1.5{\leq}{\omega})$. We find that if there had been inflationary transtion to the standard big-bang model, the Universe can undergoe a polar-type expansion during when the gravitational coupling becomes negative. The unique feature is that for the negative w, the density parameter of the post-inflationary Universe falls in a range 0<0<1 even if the Universe is geometrically flat (k = 0).

• Communications of the Korean Mathematical Society
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• v.33 no.2
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• pp.409-421
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• 2018

Let X be a complex manifold of dimension n $n{\geqslant}2$ and let ${\Omega}{\Subset}X$ be a weakly q-convex domain with smooth boundary. Assume that E is a holomorphic line bundle over X and $E^{{\otimes}m}$ is the m-times tensor product of E for positive integer m. If there exists a strongly plurisubharmonic function on a neighborhood of $b{\Omega}$, then we solve the ${\bar{\partial}}$-problem with support condition in ${\Omega}$ for forms of type (r, s), $s{\geqslant}q$ with values in $E^{{\otimes}m}$. Moreover, the solvability of the ${\bar{\partial}}_b$-problem on boundaries of weakly q-convex domains with smooth boundary in $K{\ddot{a}}hler$ manifolds are given. Furthermore, we shall establish an extension theorem for the ${\bar{\partial}}_b$-closed forms.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.642-646
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• 1989

We have developed analysis program of discharge chracteristics of KrF laser system with charge transfer type, that studied about deposited energy, nonlinear discharge, and electron number density in the laser tube. With this program, voltagr, current, and deposited energy was calculated 27 KV,32.6 KA,200 MW at total pressure 2 atm and charging voltage 33 KV, respectively. At this condition, circuit parameters are L1=150nH, R1=$0.3{\Omega}$, L2=15nH, R2= $0.3{\Omega}$. In addition, nonlinear discharge resistance and electron number density was calculated ${\infty}{\sim}0.17{\Omega}.1{\times}10^{16}cm^{-3}$, respectively.

• Bulletin of the Korean Chemical Society
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• v.35 no.1
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• pp.147-150
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• 2014

Copper ink has been prepared by mixing copper(II) formate and 2-ethyl-1-hexylammonium bicarbonate (EHABC) to overcome some weak points such as aggregation and degradation of copper nano-type ink. Ink was coated on glass substrate and calcined at $110^{\circ}C$ to $150^{\circ}C$ to generate electrically conductive copper film under two different atmospheres such as nitrogen gas and gaseous mixture of formic acid and methanol. The lowest resistivity of $1.88{\mu}{\Omega}{\cdot}cm$ of copper film was obtained at $150^{\circ}C$ in gaseous formic acid condition. The long-term resistivity shows to increase from $1.88{\mu}{\Omega}{\cdot}cm$ to $2.61{\mu}{\Omega}{\cdot}cm$ after one month.

• East Asian mathematical journal
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• v.31 no.1
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• pp.55-63
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• 2015

Let $\mathbb{B}$ be the unit ball in $\mathbb{C}^n$. For a weight function ${\omega}$, we define the generalized growth space $A^{\omega}(\mathbb{B})$ by the space of holomorphic functions f on $\mathbb{B}$ such that $${\mid}f(z){\mid}{\leq}C{\omega}({\mid}{\rho}(z){\mid},\;z{\in}\mathbb{B}$$. Our main purpose in this note is to get the corona type decomposition in generalized growth spaces on $\mathbb{B}$.

• Communications of the Korean Mathematical Society
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• v.38 no.4
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• pp.1045-1061
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• 2023

Using variational methods, Krasnoselskii's genus theory and symmetric mountain pass theorem, we introduce the existence and multiplicity of solutions of a parameteric local equation. At first, we consider the following equation $$\{-div[a(x,{\mid}{\nabla}u{\mid}){\nabla}u]\,=\,{\mu}(b(x){\mid}u{\mid}^{s(x)-2}-{\mid}u{\mid}^{r(x)-2})u\;in\;{\Omega},\\u\,=0\,on\;{\partial}{\Omega},$$ where Ω⊆ ℝ^N is a bounded domain, µ is a positive real parameter, p, r and s are continuous real functions on ${\bar{\Omega}}$ and a(x, ξ) is of type |ξ|^p(x)-2. Next, we study boundedness and simplicity of eigenfunction for the case a(x, |∇u|)∇u = g(x)|∇u|^p(x)-2∇u, where g ∈ L^∞(Ω) and g(x) ≥ 0 and the case $a(x,\,{\mid}{\nabla}u{\mid}){{\nabla}u}\,=\,(1\,+\,{\nabla}u{\mid}^2)^{\frac{p(x)-2}{2}}{\nabla}u$ such that p(x) ≡ p.

• Korean Journal of Materials Research
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• v.14 no.11
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• pp.769-774
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• 2004

15 nm-Co/15 nm-Ni/P-Si(100)[Type I] and 15 nm-Ni/15 nm-Co/P-Si(100)(Type II) bilayer structures were annealed using a rapid thermal annealer for 40sec at $700/sim1100^{\circ}C$. The annealed bilayer structures developed into composite NiCo silicides and resulting changes in sheet resistance, composition and microstructure were investigated using Auger electron spectroscopy and transmission electron microscopy. Prepared NiCoSix films were further treated in a sequential annealing set up from $900\sim1100^{\circ}C$ with 30 minutes. The sheet resistances of NiCoSix from Type I maintained less than $7\;{\Omega}/sq$. even at the temperature of $1100{\circ}C$, while those of Type II showed about $5\;{\Omega}/sq$. with the thinner and more uniform thickness. With the additive post annealing, the sheet resistance for all the composite silicides remained small up to $900^{\circ}C$. The proposed NiCoSix films were superior over the conventional single-phased silicides and may be easily incorporated into the sub-0.1 ${\mu}m$ process.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.11
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• pp.791-803
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• 2001

Mach-Zehnder type traveling-wave Ti：LiNb $O_3$ optical modulators were designed and fabricated. Optimum parameters of optical waveguides were calculated by means of the FDM. Design of CPW traveling-wave electrodes were performed by the FEM in the active region and by the CMM in the input/output section to obtain the conditions of MW effective index and impedance matching. From the measured S parameters, MW characteristics of the traveling-wane electrodes were extracted to be ${\alpha}_m$=0.05426 $\sqrt{f}$, $N_{eff}$=2.2025, and $Z_{c}$=39 ${\Omega}$. The calculated optical response R($\omega$) showed the 3 dB bandwidth of 10 GHz.z..