• 한국광학회지
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• 제16권3호
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• pp.248-253
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• 2005

다중모드간섭 기반의 $1.31/1.55{\mu}m$ 파장분리기의 크기 및 성능개선을 위해 'Improved Quasi-State' 불완전 단일상 개념을 설계에 도입하였다. 코어와 클래딩의 굴절률 차이가 작은 경우의 모드간 위상오차를 역이용 하도록 설계하여 'Quasi-State'의 출력 파워와 소멸비를 월등히 개선하였다. 다중모드간섭기의 폭이 $14.4{\mu}m$, 입력도파로의 수평 이동이 $5.3{\mu}m$가 되도록 설계한 구조를 유효굴절률법과 MPA를 사용하여 분석한 결과 최대 소멸비는 양 파장대역 모두 -25dB 이하로 나타났다. 설계된 파장분리기는 일반적인 다중 모드간섭기의 길이의 1/5정도에 불과한 $2620{\mu}m$의 간섭길이를 가진다. 소프트 리소그래피 공정을 통해 설계된 파장분리기를 제작하였으며, $1.31{\mu}m$와 $1.5{\mu}m$의 성공적인 파장분리를 확인하였다.

• 한국기계연구소 소보
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• 통권17호
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• pp.99-109
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• 1987

Mechanisms with fully elastic members must consider both inertial forces due to the rigid motion of mechanisms and due to the elastic vibration of links. The main objectives of the kineto-elasto static and dynamic analyses are to calculate the quasi-static and the time-domain responses, respectively. An iterative transfer matrix method is used for a four-bar, fully elastic linked mechanism. Houbolt direct integration scheme is incorporated for the inertial effects due to the elastic link vibration. The analytical results are compared with the experimental responses and both responses show in good agreement.

• 대한수학회지
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• 제35권3호
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• pp.503-525
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• 1998

In the theory of retrial queues it is usually assumed that the flow of primary customers is Poisson. This means that the number of independent sources, or potential customers, is infinite and each of them generates primary arrivals very seldom. We consider now retrial queueing systems with a homogeneous population, that is, we assume that a finite number K of identical sources generates the so called quasi-random input. We present a survey of the main results and mathematical tools for finite source retrial queues, concentrating on M/G/1//K and M/M/c//K systems with repeated attempts.

• 한국경영과학회지
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• 제30권2호
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• pp.131-142
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• 2005

This paper proposes queueing models for a Web server system which is composed of an infinite-buffer main server and finite-buffer auxiliary server(s). The system is modeled by the level-dependent quasi-birth- death (QBD) process. Utilizing the special structure of the QBD, we convert the infinite level-dependent QBD into a finite level-independent QBD and compute the state probabilities. We then explore the operational characteristics of the proposed web-server models and draw some useful conclusions.

• 대한수학회논문집
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• 제20권4호
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• pp.751-763
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• 2005

For a given gauge invariant state $\omega$ on the CAR algebra A isomorphic with the C$\ast$ -algebra of $2{\times}2$ complex matrices, we construct a family of quantum Markov semigroups on A which leave w invariant. By analyzing their generators, we decompose the algebra A into four eigenspaces of the semigroups and show some properties.

• 대한기계학회논문집
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• 제17권7호
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• pp.1805-1812
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• 1993

Two-dimensional spin-up in a rectangular domain is analysed by the numerical computation of the Navier-Stokes equations. The cells are in most cases generated by the vorticity developed near the uper and lower surfaces. Moreover, the movement and interaction of those vortices play a key role in establishing the quasi-steady state. The critical phenomena observed in the previous experiment turns out to be caused by the critical movement of the vortices.

• Journal of Photoscience
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• 제4권2호
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• pp.53-59
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• 1997

Absorption and fluorescence studies of E-1-(p-methoxyphenyl)-2-(p-nitrophenyl) ethene in homogeneous solvents, polymer matrix and normal and reverse micelles showing strong solvatochromic fluorescent emission properties with quasi-planar intramolecular charge transfer characteristics in the electronically excited singlet state are discussed.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2011년도 춘계학술논문집 1부
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• pp.489-492
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• 2011

Supercritical fluid technology has been an alternative for purification and separation of biological compounds in cosmetic, food, and pharmaceutical products. Solubility information of biological compounds in supercritical fluids is essential for choosing a supercritical fluid processes. The equilibrium solubility of hinokitiol was measured in supercritical carbon dioxide with a static method in the pressure range from 8 to 40 MPa and at temperatures equal to 313.2, 323.2 and 333.2 K. The experimental data were correlated well by Peng.Robinson equation of state and quasi-chemical nonrandom lattice fluid model.

• Journal of Welding and Joining
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• 제10권2호
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• pp.19-31
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• 1992

A numerical study was performed to investigate the flow field and the heat transfer characteristics occurring in high power density welding which is important in many fields of engineering applications. A two dimensional quasi-steady state of keyhole welding model is simulated by using the finite volume methods. It is shown that the shape of isothermal line is elliptic and the temperature gradient is very steep compared with other welding method and the welding speed has on welding width and observed beam power.

• Bulletin of the Korean Chemical Society
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• 제32권10호
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• pp.3555-3556
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• 2011