• 대한수학회보
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• 제58권3호
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• pp.745-765
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• 2021

Let Ω be a proper open subset of ℝⁿ and p(·) : Ω → (0, ∞) be a variable exponent function satisfying the globally log-Hölder continuous condition. In this article, the author introduces the "geometrical" variable Hardy spaces H^p(·)_r (Ω) and H^p(·)_z (Ω) on Ω, and then obtains the grand maximal function characterizations of H^p(·)_r (Ω) and H^p(·)_z (Ω) when Ω is a strongly Lipschitz domain of ℝⁿ. Moreover, the author further introduces the "geometrical" variable local Hardy spaces h^p(·)_r (Ω), and then establishes the atomic characterization of h^p(·)_r (Ω) when Ω is a bounded Lipschitz domain of ℝⁿ.

• 호남수학학술지
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• 제44권2호
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• pp.296-309
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• 2022

In this paper, we establish the Fricke Group Γ_F (N) which is a new special group of Non-Euclidean Crystallograhic (NEC) group. We obtain this group whose congruence subgroup Γ₀(N) is expanded with Fricke reflection $F(z)={\frac{1}{N{\bar{z}}}}$. Then, we research and calculate the structure of signature and fundamental domain of this group. And then, we calculate the number of boundary components in the signature for this group. Finally, we find the 2, 3, ∞ valued link periods of these boundary components with the H. Jaffee technique.

• 한국전자파학회논문지
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• 제19권3호
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• pp.281-293
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• 2008

평면형 구조에서 공간 영역 그린 함수를 구하기 위해서는 무한 Sommerfeld 적분을 계산하여야 한다. 무한 적분을 짧은 시간에 계산하기 위한 실수축 적분 방법(real axis integration method)은 주파수와 거리에 대해 넓은 범위에 걸쳐 매우 정확한 방법이지만 관측점의 수지 성분 z가 변하게 되면, 근사의 과정을 반복해야 하는 비효율성과 z가 커질수록 파수 영역 함수의 변화가 심해져 정확한 근사가 어렵다는 단점이 있다. 본 논문에서는 폐루프 적분 경로를 이용하여 파수 영역 함수를 근사화 함으로써 일반적인 마이크로스트립 구조에서 기존의 결과에 비해 정확한 closed-form 그린 함수를 구하는 방법을 제시하였다.

• Restorative Dentistry and Endodontics
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• 제25권3호
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• pp.359-370
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• 2000

The purpose of this investigation was to observe the viscoelastic properties of five commercial flowable(Aeliteflo, Flow it, Revolution, Tetric flow, Compoglass flow), three conventional hybrid(Z-100, Z-250, P-60) and two condensable(Synergy compact, SureFil) resin composites. A dynamic oscillatory shear test was done to evaluate the storage shear modulus (G'), loss shear modulus(G"), loss tangent(tan ${\delta}$) and complex viscosity(${\eta}^*$) of the resin composites as a function of frequency - dynamic frequency sweep test from 0.01 to 100 rad/s at $25^{\circ}C$ - by using Advanced Rheometric Expansion System(ARES). To investigate the effect on the viscosity of resin composites of filler volume fraction, the filler weight % and volume % were measured by means of Archimedes' principle using a pyknometer. The results were as follows 1. The complex viscosity ${\eta}^*$ of flowable resins was lower than that of hybrid resins and significant differences were observed between brands. The complex viscosity ${\eta}^*$ of condensable resins was higher than that of hybrid resins. The order of complex viscosity ${\eta}^*$ at ${\omega}$=10 rad/s was as follows, Surefil, Synergy compact, P-60, Z-250, Z-100, Aeliteflo, Tetric flow, Compoglass flow, Flow it, Revolution. The relative complex viscosity of flowable resins compared to Z-100 was 0.04~0.56 but Surefil was 30.4 times higher than that of Z-100. 2. The storage shear modulus G' and the loss shear modulus G" of flowable resins were lower than those of hybrid resins but those of condensable resins were higher. The patterns of the change of loss tangent, tan ${\delta}$, of resin composites with increasing frequency were significantly different between brands. The phase angles, ${\delta}$, ranged from $30.2{\sim}78.1^{\circ}$ at ${\omega}$=10 rad/s. 3. All composite resins represent pseudoplastic nature with increasing shear rate. 4. The complex shear modulus $G^*$ and the phase angle ${\delta}$ was represented by the frequency domain phasor form, $G^*({\omega})=G^*e^{i{\delta}}=G^*{\angle}{\delta}$. The locus of frequency domain phasor plots in a complex plane was a valuable method that represent the viscoelastic properties of composite resins. 5. There was no direct linear correlationship but a weak positive relation was observed between filler volume % or weight % and the viscosity of the resin composites.

• 전자공학회논문지SC
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• 제46권4호
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• pp.64-69
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• 2009

본 논문은 모바일 디스플레이모듈의 signal integrity와 power integrity의 시뮬레이션 방법에 관한 것이다. 본 제안 방법은 커넥터, FPCB, 드라이버IC를 포함하는 회로모듈 해석에 사용할 수 있다. 최근에 모바일 디스플레이 업계의 시리얼 인터커넥션기술에 대한 필요성 대두로 시스템오동작 방지 및 전자기파 발생을 억제하기 위해 신호선과 전원전압에 대한 섬세한 컨트롤이 필요하다. S파라미터와 Z파라미터 분석으로 주파수 도메인과 시간 도메인에서의 상관관계를 분석한다. 멀티포트 매크로를 이용하여 시간 도메인에서 sigh integrity를 power integrity에 함께 분석할 수 있다.

• Bulletin of the Korean Chemical Society
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• 제28권12호
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• pp.2539-2542
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• 2007

• 호남수학학술지
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• 제25권1호
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• pp.83-91
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• 2003

We prove a unique continuation theorem for $C^{\infty}$ functions in pseudoconvex domains in ${\mathbb{C}}^{n}$. More specifically, we show that if ${\Omega}$ is a pseudoconvex domain in ${\mathbb{C}}^n$, if f is in $C^{\infty}({\Omega})$ such that for all multi-indexes ${\alpha},{\beta}$ with ${\mid}{\beta}{\mid}{\geq}1$ and for any positive integer k, there exists a positive constant $C_{{\alpha},{\beta},{\kappa}}$ such that $$|{\frac{{\partial}^{{\mid}{\alpha}{\mid}+{\mid}{\beta}{\mid}}f}{{\partial}z^{\alpha}{\partial}{\bar{z}}^{\beta}}{\mid}{\leq}C_{{\alpha},{\beta},{\kappa}}{\mid}f{\mid}^{\kapp}}\;in\;{\Omega}$$, and if there exists $z_0{\in}{\Omega}$ such that f vanishes to infinite order at $z_0$, then f is identically zero. We also have a sharp result for the case of strongly pseudoconvex domains.

• 소음진동
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• 제9권1호
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• pp.103-112
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• 1999

A new modeling and analysis technique for one-dimensional distributed parameter systems is presented. First. discretized equations of motion in Laplace domain are derived by applying discretization methods for partial differential equations of a one-dimensional structure with respect to spatial coordinate. Secondly. the z and inverse z transformations are applied to the discretized equations of motion for obtaining a dynamic matrix for a uniform element. Four different discretization methods are tested with an example. Finally, taking infinite on the number of step for a uniform element leads to an exact dynamic matrix for the uniform element. A generalized modal analysis procedure for eigenvalue analysis and modal expansion is also presented. The resulting element dynamic matrix is tested with a numerical example. Another application example is provided to demonstrate the applicability of the proposed method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1977-1978
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• 2008

In this paper, we compare performance of common-mode rejection between a differential and a non-differential amplifier system with two electrodes. A differential amplifier system is constant for common-mode rejection ratio(CMRR) on the frequency domain. But a non-differential amplifier's CMRR is determined by $Z_{FB}/Z_e$ ($Z_{FB}$ ; feedback impedance, $Z_e$; electrode impedance). There is trade-off between a non-differential amplifier's CMRR and its differential input impedance. And a non-differential amplifier system has some advantages for a bio-potential measurement with two electrodes because a designer can control the impedance between the body and system's common.

• 충청수학회지
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• 제31권1호
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• pp.47-52
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• 2018

Let ${\delta}$ be a derivation in a noetherian integral domain A. It is shown that a natural map induces a homeomorphism between the spectrum of $A[z;{\delta}]$ and the Poisson spectrum of $A[z;{\delta}]_p$ such that its restriction to the primitive spectrum of $A[z;{\delta}]$ is also a homeomorphism onto the Poisson primitive spectrum of $A[z;{\delta}]_p$.