• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전력기술부문
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• pp.240-242
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• 2005

전력계통안정화장치(PSS)는 전력안정화를 위하여 발전기의 여자기에 보조신호를 주입하여 전력계통의 진동문제를 해결할 수 있는 장치이다. 본 논문은 기존의 비실시간 툴 (PSS/E, EMTDC/PCAD.,)을 사용한 경우와 달리 실시간 시뮬레이션 툴을 사용하여 전력계통안정화장치(Power System Stabilizer : PSS)의 영향 및 효과를 검토하였다. 이에 사용된 실시간 툴은 RTDS의 PC 버전인 RSCAD를 이용하여 분석하였다. 모의에 사용된 선로는 3상 3회선 송전선로이며 무한모선에 연결하였다. 사고는 3회선 중의 1회선 중앙에 3상 지락 상정사고를 발생시켜 선로 차단 및 재투입을 고려하여 실시하였다. 본 연구에서 RSCAD에 대한 기존의 전통적인 형태인 IEEE의 PSS1A type과 보다 정교한 이중구조를 가진 PSS2A type을 사용하여 검토하였다. IEEE의 PSS1A type은 각속도 ${\omega}$를 측정하여 사용하고 PSS2A type은 각속도 ${\omega}$와 유효전력 P를 측정하여 사용할 수 있는 형태이다. 그리고 실시간 시뮬레이션 결과는 각속도 ${\omega}$와 유효전력 P를 측정하여 PSS의 입력에 주입하고 이에 대한 효과를 비교하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기물성,응용부문
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• pp.48-50
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• 2005

As technology is developed, customers want to use many functions in one system. Manufacturers want to reach the customer's needs, make systems more small, thin, light-weight. To make them real, it is necessary to make components to be small and thin. But components of power stage are big, thick and heavy-weighted yet. especially power inductor is the most significant component. This paper proposed a novel chip-type power inductor I-type inductor. Inductor that proposed has 3225-size, 5.6uH and 1.3A of max saturation current. And it has $R_{DC}$ of $0.25{\Omega}$ which is smaller than $0.45{\Omega}$ of chip-type inductor and $0.9{\Omega}$ of coil-type inductor.

• Journal of applied mathematics & informatics
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• 제28권1_2호
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• pp.217-231
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• 2010

We consider a class of elliptic problems of a logistic type $$-div(|{\nabla}_u|^{m-2}{\nabla}_u)\;=\;w(x)u^q\;-\;(a(x))^{\frac{m}{2}}\;f(u)$$ in a bounded domain of $\mathbf{R}^N$ with boundary $\partial\Omega$ of class $C^2$, $u|_{\partial\Omega}\;=\;+{\infty}$, $\omega\;\in\;L^{\infty}(\Omega)$, 0 < q < 1 and $a\;{\in}\;C^{\alpha}(\bar{\Omega})$, $\mathbf{R}^+$ is non-negative for some $\alpha\;\in$ (0,1), where $\mathbf{R}^+\;=\;[0,\;\infty)$. Under suitable growth assumptions on a, b and f, we show the exact blow-up rate and uniqueness of the large solutions. Our proof is based on the method of sub-supersolution.

• 대한수학회논문집
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• 제11권2호
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• pp.503-514
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• 1996

We consider non-constant coefficient elliptic equations of the type -div(a \bigtriangledown u) = f$, and employ the P-version of the finite element method as a numerical method for the approximate solutions. To compute the integrals in the variational form of the discrete problem we need the numerical quadrature rule scheme. In practice the integrations are seldom computed exactly. In this paper, we give an $L_2(\Omega)$-error estimate of $\Vert u = \tilde{u}_p \Vert_{0,omega}$ in comparison with $\Vert u = \tilde{u}_p \Vert_{1,omega}$, under numerical quadrature rules which are used for calculating the integrations in each of the stiffness matrix and the load vector.

• The Korean Journal of Physiology and Pharmacology
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• 제1권6호
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• pp.625-637
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• 1997

Calcium ions are implicated in a variety of physiological functions, including enzyme activity, membrane excitability, neurotransmitter release, and synaptic transmission, etc. Calcium antagonists have been known to be effective for the treatment of exertional angina and essential hypertension. Selective and nonselective voltage-dependent calcium channel blockers also have inhibitory action on the acute and tonic pain behaviors resulting from thermal stimulation, subcutaneous formalin injection and nerve injury. This study was undertaken to investigate the effects of iontophoretically applied $Ca^{++}$ and its antagonists on the responses of WDR (wide dynamic range) cells to sensory inputs. The responses of WDR cells to graded electrical stimulation of the afferent nerve and also to thermal stimulation of the receptive field were recorded before and after iontophoretical application of $Ca^{++}$, EGTA, $Mn^{++}$, verapamil, ${\omega}-conotoxin$ GVIA, ${\omega}-conotoxin$ MVIIC and ${\omega}-agatoxin$ IVA. Also studied were the effects of a few calcium antagonists on the C-fiber responses of WDR cells sensitized by subcutaneous injection of mustard oil (10%). Calcium ions and calcium channel antagonists ($Mn^{++}$, verapamil, ${\omega}-conotoxin$ GVIA & ${\omega}-agatoxin$ IVA) current-dependently suppressed the C-fiber responses of WDR cells without any significant effects on the A-fiber responses. But ${\omega}-conotoxin$ MVIIC did not have any inhibitory actions on the responses of WDR cell to A-fiber, C-fiber and thermal stimulation. Iontophoretically applied EGTA augmented the WDR cell responses to C-fiber and thermal stimulations while spinal application of EGTA for about $20{\sim}30\;min$ strongly inhibited the C-fiber responses. The augmenting and the inhibitory actions of EGTA were blocked by calcium ions. The WDR cell responses to thermal stimulation of the receptive field were reduced by iontophoretical application of $Ca^{++}$, verapamil, ${\omega}-agatoxin$ IVA, and ${\omega}-conotoxin$ GVIA but not by ${\omega}-conotoxin$ MVIIC. The responses of WDR cells to C-fiber stimulation were augmented after subcutaneous injection of mustard oil (10%, 0.15 ml) into the receptive field and these sensitized C-fiber responses were strongly suppressed by iontophoretically applied $Ca^{++}$, verapamil, ${\omega}-conotoxin$ GVIA and ${\omega}-agatoxin$ IVA. These experimental findings suggest that in the rat spinal cord, L-, N-, and P-type, but not Q-type, voltage-sensitive calcium channels are implicated in the calcium antagonist-induced inhibition of the normal and the sensitized responses of WDR cells to C-fiber and thermal stimulation, and that the suppressive effect of calcium and augmenting action of EGTA on WDR cell responses are due to changes in excitability of the cell.

• 복합신소재구조학회지
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• 제4권1호
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• pp.14-20
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• 2013

• 대한수학회논문집
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• 제36권2호
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• pp.247-256
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• 2021

Using variational methods, we show the existence of a unique weak solution of the following singular biharmonic problems of Kirchhoff type involving critical Sobolev exponent: $$(\mathcal{P}_{\lambda})\;\{\begin{array}{lll}{\Delta}^2u-(a{\int}_{\Omega}{\mid}{\nabla}u{\mid}^2dx+b){\Delta}u+cu=f(x){\mid}u{\mid}^{-{\gamma}}-{\lambda}{\mid}u{\mid}^{p-2}u&&\text{ in }{\Omega},\\{\Delta}u=u=0&&\text{ on }{\partial}{\Omega},\end{array}$$ where Ω is a smooth bounded domain of ℝⁿ (n ≥ 5), ∆² is the biharmonic operator, and ∇u denotes the spatial gradient of u and 0 < γ < 1, λ > 0, 0 < p ≤ 2^# and a, b, c are three positive constants with a + b > 0 and f belongs to a given Lebesgue space.

• 센서학회지
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• 제3권1호
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• pp.83-87
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• 1994

EBE법으로 S,In과 Cu를 순차적으로 증착하여 S/In/Cu 적층막을 제작하고, 진공 및 별도 S(Sulphur)공급하면서 열처리하여 다결정 $CuInS_{2}$ 박막을 제작하였다. 진공중에서 열처리한 박막은 chalcopyrite 구조를 갖는 n형 $CuInS_{2}$ 이었고 이때 최저 저항율은 $142{\Omega}Cm$이었다. 또한 별도 S 공급하면서 열처리한 박막은 p형으로 chalcopyrite 구조를 갖고 성장되었으며 최저 저항율은 $137{\Omega}Cm$ 이었다.

• 조명전기설비학회논문지
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• 제19권5호
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• pp.17-22
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• 2005

본 연구에서는 직경이 50[mm], 두께가 4.5[mm]인 디스크형 압전 변압기의 구동부와 발전부의 전극 면적비를 각각 1.4:1, 2:1 및 3:1로 분할하여, 부하 저항을 변화(100${[\Omega]}\~70{[k\Omega]}$)시키면서 전기적 특성을 측정하고, 이를 토대로 한 압전변압기의 승압비에 관한 메카니즘을 정량적 및 정성적으로 해석하였다.

• 대한화학회지
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• 제41권3호
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• pp.138-143
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• 1997

30$^{\circ}C$의 센(-Ho < 2.23) 과염소산 수용액 속에서 3,3-bis(methylthio)-2-propen-1-phenyl-1-one 유도체들의 산-촉매 가수분해 반응을 속도론적으로 연구하였다. 치환기 효과, 가수분해 생성물의 분석, Bunnett식 및 Bunnett-Olsen식의 hydration 파라미터(${\omega}$및 ${\phi}$)로부터 3.8 M 이하의 묽은 산 용액에서는 A-1형 반응($3.3 >{\omega},\;0.58 > {\phi}$ 및 ${\rho} < 0$)이 그리고 3.8 M 이상의 진한 산 용액에서는 A-2형 반응($0 <{\omega},\;0 < {\phi}$ 및 ${\rho} > 0$) 메카니즘으로 산-촉매 가수분해 반응이 일어난다.