• East Asian mathematical journal
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• 제1권
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• pp.89-100
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• 1985

A mapping f: X$\rightarrow$Y is introduced to be weakly irresolute if, for each x $\varepsilon$ X and each semi-neighborhood V of f(x), there exists a semi-neighborhood U of x in X such that $f(U){\subset}scl(V)$. It will be shown that a mapping f: X$\rightarrow$Y is weakly irresolute iff(if and only if) $f^{-1}(V){\subset}sint(f^{_1}(scl(V)))$ for each semiopen subset V of Y. The relationship between mappings described in [3,5, 6,8] and a weakly irresolute mapping. will be investigated and it will be shown that every irresolute retract of a $T_2$-space is semiclosed.

• 한국철도학회논문집
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• 제10권2호
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• pp.112-116
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• 2007

In this paper, we proposed a selection and application recommendations of ZnO arresters for DC electric traction vehicles. To decide the Continuous Operating Voltage($U_C$), the Rated Voltage($U_r$), and the Nominal Discharge Current(In), we measured and analyzed system voltages and surge currents flowing the arrester installed on a DC electric traction vehicle under running state. System voltages measured up to 1,800 V in 1,500 V-system, and surge currents were recorded up to 3 times per a running-service-route and their magnitudes were ranges of $150A{\sim}2kA$. From these results and a standard EN50163, we could proposed $U_C$, $U_r$, and In available for the 1,500 VDC electric traction vehicles.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.265.1-265.1
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• 2016

여러 application에 적용하기 위하여 p-type SnO 박막과 전극 간의 접촉 저항을 분석이 필요하였다. 이를 Transmission Line Method(TLM) 패턴 소자를 제작한 후 전기적 특성을 분석함으로써 알 수 있었다. $Si/SiO_2$ 기판에 Reactive Magnetron Sputtering법을 이용하여 c축 우선 배향된 SnO를 100nm 증착하고 photolithography 공정을 통해 전극을 패턴화하여 100nm 두께로 증착하였다. 전극 간 거리는 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, $1024{\mu}m$로 각각 2배씩 증가하는 패턴이고 폭 W는 $300{\mu}m$ 이다. p-type SnO 의 경우, work function이 4.8eV이기 때문에 전극과 ohmic contact이 되기 위해서는 4.8eV보다 높은 work function 값을 가지는 전극이 필요하였다. 이 조건과 맞는 후보로 Ni(5.15eV), ITO(5.3eV)를 설정한 후 소자를 제작하였다. 제작된 소자는 열처리 하지 않은 소자와 Rapid Thermal Annealing(RTA) 장비에서 $100^{\circ}C$, $200^{\circ}C$, $300^{\circ}C$에서 각각 1분씩 열처리한 소자의 특성을 분석하였다. 열처리 하지 않은 소자의 경우 Ni 전극의 specific contact resistance는 $3.42E-2{\Omega}$의 값을 나타내었고, ITO의 경우 $3.62E-2{\Omega}$값을 나타내었다.

• 한국해양바이오학회지
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• 제2권2호
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• pp.123-125
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• 2007

Vibrio anguillarum is a gram-negative bacterium that causes vibriosis in approximately 80 different fish species. V. anguillarum produces several exotoxins are correlated with the pathogenesis of vibriosis. This study is focused on the composition of the outer membrane vesicle. Most of gram-negative bacteria produce outer membrane vesicle (OMV) during cell growth. OMV was formed from the outer membrane surface of cell and than released to extracellular environment. OMV consists of outer membrane lipids, outer membrane protein (OMP), LPS, and soluble periplasmic components. Also, they contain toxins, adhesions, and immunomodulatory. Many gram-negative bacteria were studied out forming OMV. In Vibrio sp., formation of OMV by electron microscopy has been reported from V. cholerae and V. parahaemolyticus. In present study, we isolated OMV from V. anguillarum and OMV protein was separated by SDS-PAGE. Magor band was sliced and analyzed by MALDI-TOF. The major protein band of 38kDa was identified as OmpU by MALDI-TOF MS analysis.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.602-602
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• 2013

산화아연(ZnO)은 직접 천이 와이드 밴드갭(3.37 eV)과 큰 excitation binding energy (60 meV)를 갖는 II-VI 반도체로 광촉매, light emitting diodes (LED), dye-sensitized solar cell 등의 여러 가지 분야에서 각광받고 있는 물질이다. ZnO는 열역학적으로 안정한 polar terminated (001)면과 nonpolar low-symmetry (100)면을 갖으며 (100)면이 (001)면보다 더 안정하기 때문에 (100)방향의 일차원구조가 쉽게 합성된다. 이러한 일차원 구조는 빛의 산란을 유도하여 더 많은 빛의 흡수를 야기 시킬 뿐만 아니라 일차원 구조를 따라 효율적인 전하 전달을 가능하게 한다. 본 연구에서는 일차원 구조의 장점을 살리면서 더 넓은 표면적을 갖는 hierarchical ZnO nanowire 구조를 수열합성법과 스퍼터링증착법을 이용하여 합성하였다. Hierarchical ZnO nanowire는 SEM, TEM을 이용하여 구조를 관찰하였고 UV-visable spectroscopy를 이용하여 일차원 구조의 ZnO nanowire와의 absorbance, transmittace 차이를 확인하였다.

• 대한수학회지
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• 제57권6호
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• pp.1347-1372
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• 2020

We study bifurcation for the following fractional Schrödinger equation $$\{\left.\begin{eqnarray}(-{\Delta})^su+V(x)u&=&{\lambda}f(u)&&{\text{in}}\;{\Omega}\\u&>&0&&{\text{in}}\;{\Omega}\\u&=&0&&{\hspace{32}}{\text{in}}\;{\mathbb{R}}^n{\backslash}{\Omega}\end{eqnarray}\right$$ where 0 < s < 1, n > 2s, Ω is a bounded smooth domain of ℝⁿ, (-∆)^s is the fractional Laplacian of order s, V is the potential energy satisfying suitable assumptions and λ is a positive real parameter. The nonlinear term f is a positive nondecreasing convex function, asymptotically linear that is $\lim_{t{\rightarrow}+{\infty}}\;{\frac{f(t)}{t}}=a{\in}(0,+{\infty})$. We discuss the existence, uniqueness and stability of a positive solution and we also prove the existence of critical value and the uniqueness of extremal solutions. We take into account the types of Bifurcation problem for a class of quasilinear fractional Schrödinger equations, we also establish the asymptotic behavior of the solution around the bifurcation point.

• 한국재료학회지
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• 제12권1호
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• pp.94-99
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• 2002

The electrical properties of porous $SiO_2/ITO$ nano thin film were studied by complex impedance and conductive mechanisms were analyzed. According to the results of complex impedance, the activation energy of $SiO_2/ITO$ and $Zn-SiO_2/ITO$ were 0.309 eV, 0.077 eV in below $450^{\circ}C$ and 0.147 eV in over $450^{\circ}C$, respectively. In case of $SiO_2/ ITO$, slightly direct tunneling occurred at room temperature. The contribution for conduction was very tiny because of high barrier of silica. However, the conductivity abruptly increased in over $300^{\circ}C$ by Thermally assisted tunneling. In case of $Zn-SiO_2/ITO$, high conductivity in 1.26 ${\Omega}^{ -1}{cdot}cm^{-1}$ at room temperature appeared by space charge conduction or Frenkel-poole emission that Zn ions play a role as localized electron states.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.145.1-145.1
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• 2013

A prerequisite for the development of graphene-based field effect transistors (FETs) is reliable control of the type and concentration of carriers in graphene. These parameters can be manipulated via the deposition of atoms, molecules, and polymers onto graphene as a result of charge transfer that takes place between the graphene and adsorbates. In this work, we demonstrate a unique and facile methodology for the homogenous and stable p-type doping of graphene by hybridization with ZnO thin films fabricated by MeV electron beam irradiation (MEBI) under ambient conditions. The formation of the ZnO/graphene hybrid nanostructure was attributed to MEBI-stimulated dissociation of zinc acetate dihydrate and a subsequent oxidation process. A ZnO thin film with an ultra-flat surface and uniform thickness was formed on graphene. We found that homogeneous and stable p-type doping was achieved by charge transfer from the graphene to the ZnO film.

• The Korean Journal of Ceramics
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• 제3권4호
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• pp.245-248
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• 1997

Photoluminescence (PL) and cathodoluminescence (CL) characteristics of Ce-activated $Y_{2-x}Ce_xSiO_5$ have been investigated as functions of Ce concentration and firing condition. According to the X-ray, PL and CL results, $Y_2SiO_5$ is found to have two phases depending on the firing temperature. For the specimen fired above 127$0^{\circ}C$, the emission band peaked at 395nm with a shoulder at 424 nm under ultraviolet (u.v.) and cathode-ray (c.r.) excitation. However, for the specimen fired below 120$0^{\circ}C$ in air the peak was observed at 424 nm and it shifted to longer wavelength with reduction level. The reduced specimen for x=0.02 showed the brightest emission under u.v. excitation whereas under c.r. excitation the brightest emission was observed for the reduced specimen for x=0.06.

• 대한화학회지
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• 제13권1호
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• pp.16-24
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• 1969

Ni, Co, Zn, Cd, Mn, Mg, Ca, Sr, Ba 등의2가 금속과 U(VI) 및 V(IV)의 이온이 만드는 $MCup_2$ 조성의 cupferrates 착화합물에 관하여, 그 용해도가 좋은 dioxane-$H_2O$, methanol-$H_2O$, ethanol-$H_2O$ 및 2-propanol-$H_2O$의 혼합용매를 사용하여, 그들의 몰분율을 변화시키면서 제 1, 제 2 및 전체의 열역학적인 안정도상수를 전위차적정법에 의하여 측정하고, 안정도 상수와 유기용매의 몰분율에 관한 실험식을 얻었다. 한편 분광광전법에 의하여 가능한 cupferrates의 전체 안정도 상수를 측적하여 이들과 비교하였다. 2가 금속 cupferrates의 안정도상수는 위에 적은 금속의 순서로 감소하고, 이들의 log $K_1$은 log $K_2$보다 크지만, U(VI)과 V(IV)의 cupferrates는 log $K_1$$K_2$여서 1:1과 1:2 착화합물 사이에 구조 변화가 있는듯하다. 몰분율이 영인 점에서의 안정도상수는 금속 cupferrates의 수용액에서의 용해반응의 평형상수에 해당하며, 금속의 착화합물의 안정도상수와 용해도와는 무관하고, K<$10^5$인 cupferrates에 관해서는 분광전법을 적용하기 어렵다.