• Journal of Mechanical Science and Technology
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• 제20권7호
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• pp.941-949
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• 2006

Nonlinear behavior analysis was used to verify whether a one-way clutch is effective for reducing the torsional vibration of a paired spur gear system under periodic excitation. The dynamic responses were studied over a wide frequency range by speed sweeping to check the nonlinear behavior using numerical integration. The gear system with a one-way clutch showed typical nonlinear behavior. The oscillating component of the dynamic transmission error was reduced over the entire frequency range compared to a system without a one-way clutch. The one-way clutch also eliminated unsteady continuous jump phenomena over multiple solution bands, and prevented double-side contact, even with very small backlash. Installing a one-way clutch on both sides of the gear system was more effective at mitigating the negative effects of external periodic excitation and various parameter changes than a conventional gear system without a one-way clutch.

• The Journal of the Acoustical Society of Korea
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• 제28권2E호
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• pp.51-59
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• 2009

Mutual radiation impedance becomes more important in the design and analysis of acoustic transducers for higher power, better beam pattern, and wider bandwidth at low frequency sonar systems. This review paper focused on literature survey about the researches of mutual radiation impedance in the acoustic transducer arrays over 60 years. The papers of mutual radiation impedance were summarized in terms of transducer array structures on various baffle geometries such as planar, cylindrical, spherical, conformal, spheroidal, and elliptic cylindrical arrays. Then the computation schemes of solving conventional quadruple integral in the definition of mutual radiation impedance were surveyed including spatial convolution method, which reduces the quadruple integral to a double integral for efficient computation.

• 패션비즈니스
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• 제1권1호
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• pp.53-70
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• 1997

The purpose of this thesis is to make clear particulartity of young adult generation which leads industry in their demands so that fashion trends are foresaw, and to describe style of costume satisfied with picture of new male. This thesis is to consider young adult style of costume in terms of double root described by W$\ddot{o}$lfflin in the internal meaning and the external form, so as to analyze their unique style. In conclusion, domestic young adult style of costume is embodied in the internal meanings of individuality, aestheticism and new classicism in terms of the external forms which means body-priority-form by open-form, whole-form, integration-form, rounded-form, indeterminate-form. With these results, domestic fashion industry is demanded to be from classic to modern expressions so as to be reflected in sophisticated masculinity of young adult.

• 전산구조공학
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• 제11권4호
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• pp.135-146
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• 1998

대형 시스템의 건전성 평가를 위한 동적 재하시험에 있어서 변위를 측정하는 것보다 가속도를 측정하는 것이 수월하나 대부분의 공학적 기준은 응력과 비례관계를 지니는 변화를 기준으로 하고 있다. 본 연구에서는 시스템의 재하시험시 측정된 가속도신호를 이용하여 변위응답을 산정하는데 그 목적을 두고 적분을 위한 신호처리시 발생되는 문제점을 정상상태 및 천이영역에 대하여 규명하였다. 기존의 연구에서 고려하지 못하였던 초기조건의 항을 도입함으로써 시간영역의 적분과 주파수영역의 적분결과가 일치함을 해석적으로 입증하였으며 이동하중을 받는 보의 동적거동에 대하여 제시된 타당성을 검증하였다.

• Structural Engineering and Mechanics
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• 제38권3호
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• pp.301-314
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• 2011

The paper constitutes the second part of the author's study. The first part (Podworna 2010) formulates four fundamental tasks in dynamics of the bridge-track-train systems. The following cyclic moving loads are considered: a concentrated forces stream (model P), an unsprung masses stream (model M), a single-mass viscoelastic oscillators stream (model $M_o$) and a double-mass viscoelastic oscillators stream (model $MM_o$). Three problems precluding to the numerical simulations have been developed, i.e., prediction of the forced resonances, the parameters of integration of equations of motion, the output results. A computer programme was written in Pascal and numerical research in the scope of the fundamental tasks was worked out. The investigations were focused on adequacy evaluation of the moving load models, P, M, $M_o$, $MM_o$, in predicting dynamic processes in railway bridges.

• Journal of Information Display
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• 제5권2호
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• pp.1-5
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• 2004

We developed an a-Si TFT-LCD panel with integrated gate driver circuit using a standard 5-MASK process. To minimize the effect of the a-Si TFT current and LC's capacitance variation with temperature, we developed a new a-Si TFT circuit structure and minimized coupling capacitance by changing vertical architecture above gate driver circuit. Integration of gate driver circuit on glass substrate enables single chip and 3-side free panel structure in a-Si TFT-LCD of QVGA ($240{\times}320$) resolution. And using double ASG structure the dead space of TFT-LCD panel could be further decreased.

• 대한전기학회논문지
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• 제39권7호
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• pp.740-748
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• 1990

In this paper, we consider the problem of parameter estimation, i.e., definding the internal structure of a linear distribution parameter system from its input/output data. First, a linear partial differential equation describing the system is double-integrated with respect to two variables and then transformed into an integral equation. Next the Walsh Operation Matrix for Walsh function and their integration are introduced to transform the integral equation into algebraic simultaneous equations. Finally, we develop an algorithm to estimate the parameters of the linear distributed parameter system from the simple linear algebraic simultaneous equations. It is also shown that our algorithm could be effective in real time data processing since it uses the Fast Walsh Transform.

• 한국자기공명학회논문지
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• 제6권2호
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• pp.103-112
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• 2002

The photoproduced cation radical of N-methylphenothiazine $(PC_1)$ doped into phenyltriehtoxysilane (PhiTEOS), vinyltriethoxysilane (VTEOS) and methyltriethoxysilane (METOS) was studied with electron spin resonance (ESR) and electron nuclear double resonance (ENDOR). The photoinduced charge separation efficiency was determined by integration of ESR spectra which correspond to the amount of photoproduced cation radical in the matrices. This was correlatively studied with the polarity and pore size of the gel matrices. The relative polarity of the matrices was determined by measuring ${\lambda}_{max}$ values of $PC_1$ in the different matrices. The relative pore size among the matrices was determined by measuring relative proton matrix ENDOR line widths of the photoproduced cation of $PC_1$. The decay kinetic constants of the cation radical of $PC_1$ in the different matrices with relatively studied with fitting the biexponential decay curves after exposure at the ambient condition. This is correlatively interpreted with the polarity and pore size of the matrices.

• 대한수학회보
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• 제61권4호
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• pp.1033-1051
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• 2024

In this paper, we define a parametric variant of generalized Euler sums and construct contour integration to give some explicit evaluations of these parametric Euler sums. In particular, we establish several explicit formulas of (Hurwitz) zeta functions, linear and quadratic parametric Euler sums. Furthermore, we also give an explicit evaluation of alternating double zeta values ${\zeta}({\bar{2j}};\,2m+1)$ in terms of a combination of alternating Riemann zeta values by using the parametric Euler sums.

• 에너지공학
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• 제5권2호
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• pp.160-169
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• 1996

석탄가스화복합발전소의 가스터빈 공기압축기와 공기분리장치 간의 최적 연계설계를 위한 매개변수 연구를 수행하였다. 본 연구에서는 복수형 증류탑공정의 공기분리장치를 사용하였으며, 증류탑공정의 특성으로부터 압축기와의 연계조건인 공기추출량, 공기추출압력 및 공기/질소 열교환 조건들을 정의, 수식화하였다. 공기분리장치와 연계된 가스터빈용 공기압축기의 성능변화는 유선곡률방법과 압력손실모델을 결합한 해석방법을 사용하였으며, 예측결과들을 실제 압축기성능 시험결과와 비교하여 예측정확도를 검증하였다. 본 압축기성능 해석방법을 이용하여, 압축기와 공기분리장치의 연계조건인 열교환기의 핀치포인트 온도차, 추출공기량 및 추출 공기압력이 압축기성능에 미치는 영향을 정량적으로 검토하였다. 공기추출량이 늘어나거나 핀치포인트 온도차가 커질수록, 압축기의 압축비 및 소요동력은 증가하였다. 반면에, 압축기 효율은 공기추출량의 증가에 따라 고압공기추출시에는 저하되고, 저압공기추출시에는 향상되었다. 더나아가, 압축기의 일반화된 입구조건과 효율간의 특성곡선을 통해, 압축기 효율을 극대화 할 수 있는 압축기/공기분리장치간의 최적연계조건을 제시하였다.