• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1993.04a
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• pp.23-29
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• 1993

내부공진 (.omega.$_{3}$ = .omega.$_{1}$ + 2.omega.$_{2}$)을 가진 원판 의 조합공진(.OMEGA. = 2.omega.$_{1}$ + .omega.$_{2}$)응답의 안정성 을 해석한 결과 다음과 같은 결론을 얻었다. 1) 모든 진폭이 0(.alpha.$_{1}$=.alpha.$_{2}$=.alpha.$_{3}$=0)인 공진응답 은 매개변수의 값에 관계없이 안정하다. 2) 모든 진폭이 0이 아닌 (.alpha.$_{1}$.neq.0, .alpha.$_{2}$.neq.0, .alpha.$_{3}$.neq.0) 공진응답은 쌍으로 존재하는데 진폭이 큰 응답(upper branch)은 안정하나 진폭이 작은 응답(lower branch)은 불안정하다. 3) 진폭이 0이 아닌 공진응답이 존재하지 않는 경우에는 선형계와 마찬가지 로 모든 진폭이 0이 공진응답(결과적으로 비공진 응답)이 계의 응답을 지배 하지만 모든 진폭이 0이 아닌 공진응답이 존재하는 경우에는 안정한 공진응 답이 2개이므로 초기조건이 실제의 응답을 결정하게 된다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.12 no.2
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• pp.133-138
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• 1987

In this paper the tuning characteristics of resonant frequencies are experimentally studied through the variation of the length of the inner conducting rod in a re-enterant eavity resonator. The re-enterant eavity resonator consists of a coaxial cable and a cylindrical wave guide. The length of the inner conducting rod can be varied to the longitudinal direction. The resonant frequencies of TMonq modes are measured according to the arbitrary length. In order to verify the propriety of experimental results, experimental results are compared with other theoretical results. The results in this paper can be applied to wave meter and resonant circuit of amplifier. They will be use to vary resonant frequencies of a dielectric resonator in MIC and filter.

• Journal of the korean Society of Automotive Engineers
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• v.5 no.3
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• pp.1-7
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• 1983

승용차의 차실 내부소음 특성 및 저감에 과한 일련의 고찰로 다음의 결론을 얻었다. (1) 차실 내부소음의 주된 근원은 회전속도의 제이고주파에 해당되는 주파수 성분이 지배적이다. (2) 차실 공진(명) 음은 engine으로부터의 진동 입력에 대한 차체의 ring mode 공진 및 차실 공명현상으로 발생되며 실험 결과는 종래의 연구 결과들과 잘 일치되었다. (3) 차실 내부소음이 차체의 구조, 진동 및 실내 음향공영에 크게 의존하기 때문에, 이 두가지 요소로써 문제의 발견이 가능하며 이들을 이용한 저감대책 수립은 효과적이다. (4) 차실 내부소음의 저감을 위하여 구조적damping이나 흡음재의 적절한 사용 등이 다소의 효 과를 주나 공진(명) 음의 근본적인 대책이 되지 못하며, 차실 공명 특성을 변화시키는 것은 사 실상 불가능하다. (5) 차체의 구조적 진동 특성을 고려하여 보강된 차량의 경우 문제 영역에서의 현저한 소음감 소효과가 얻어졌다. 그러나 이와 같은 방안의 적용은 개발의 초기 단계에서 실시됨이 바람직하다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.4
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• pp.201-208
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• 2013

This paper is a study of an empirical design of an open-ended coaxial cavity resonator. It can be done by using the radius of the inner conductor, the inner radius and the length of the resonator. However, the basic coaxial transmission -line theory can be seen that the characteristics of the resonant frequency and the Q value are varied by the change of length, regardless of the value of radius of the inner conductor and inner radius of the resonator. We find out the impact of radius of the inner conductor, inner radius of the resonator and the length of the resonator parameter and propose the optimized empirical resonator design method by reducing the error between the theoretical value and the design value. Based on the simulation, several resonators are fabricated by the size of 14 mm for the radius of inner conductor, 2 mm, 5 mm, 10 mm respectively for the inner radius of resonator, and 8.5 mm for the length of the resonator. The resonant frequencies of the produced resonators were measured at 6.1, 5.7, 6.5 GHz respectively. According to the result of simulation and measurement, we know that we can design the relatively exact open-ended coaxial cavity resonator by applying the basic coaxial transmission-line theory directly when the length of the resonator is less than 10 mm, and adding the correction factor of 0.5 GHz to the calculated resonant frequency in case of more than 10 mm of the length of the resonator.

• Korean Journal of Optics and Photonics
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• v.8 no.6
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• pp.456-460
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• 1997

Several methods of aligning ring type cavities have been investigated for long time. The measurement of cavity transmission spectrum control is somewhat effective due to aligning cavity with measuring cavity loss at the same time. In this research, four mirrors are aligned and attached by the measurement of pulse width of the transmitted light. The intracavity loss is optimized to about 0.98%, giving the calculated total reflection coefficient of about 99.02%.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.11
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• pp.26-35
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• 2007

We characterized the properties of the fabricated filter with the total internal reflection mirror (TIR) in the rectangular ring resonator and very small multimode interference (MMI) couplers on an InP material platform for photonic integrated circuits. Coupling power in and out of a resonator is increased by using an optimum MMI length of 110 ${\mu}m$ and a width of 9 ${\mu}m$, respectively. The semiconductor optical amplifier with the length of 120 ${\mu}m$ is integrated in the resonator to compensate the loss of the internal waveguide and the TIR mirror. A free spectral range of approximately 2 nm (244 GHz) is observed with an on-off ratio of 13 dB. The curve fitting also yields the power coupled per pass as 42%. To reach critical coupling at this coupling level would require a round trip loss of about 2.4 dB.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1603-1604
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• 2006

본 논문은 구멍(aperture)이 나있는 육면체 진기에 전자파가 조사 되었을 때, 공진기 내부에 침투한 전자파를 Modal MoM 수치계산법을 이용하여 추정하였다. 공진기 내부의 전자파는 cavity Green 함수로, 외부는 자유 공간 Green 함수로 표현 할 수 있고, 구멍이 난 부분에서 전계와 자계의 접선 성분이 연속하다는 경계조건을 이용하여, 차폐하고자 하는 도체공간 내부에 침투한 전자파를 알 수 있다.

• Korean Journal of Optics and Photonics
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• v.11 no.4
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• pp.294-298
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• 2000

The output characteristics of intracavity frequency doubling of laser-diode end-pumped Nd:S-VAP laser were investigated. Nd:S-VAP is suitable for a microchip laser medium, which has a low threshold property because of a very high value of the stimulated emission cross-section and lifetime product. The threshold energy measured was 81 J.ll. The second harmonic output energy measured was $126\mu\textrm{J}$at a pump energy of $2\mu\textrm{J}$. We described for intracavity frequency doubling by using theoretical calculations. Q-switched second harmonic energy measured was $15\mu\textrm{J}$per pulse with a pulse-width of 26 ns. at a pump energy of 2 mJ and an $M^2$ of 1.47 represented a good beam quality. ality.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.11
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• pp.2098-2110
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• 1992

An analysis is presented for the combination resonance of a clamped circular plate, which occurs when the frequency of the excitation is near the combination of the natural frequencies, that is, when ohm.=2.0mega.／sub 1／+omega.／sub 2／. The internal resonance, Omega.／sub 3／=omega.／sub 1／+2.omega.／sub 2／, is considered and its influence on the response is studied. The clamped circular plate experiencing mid-plane stretching is governed by a nonlinear partial differential equation. By using Galerkin's method the governing equation is reduced to a system of nonautonomous ordinary differential equations. The method of multiple scales is used to obtain steady-state responses of the system. Results of numerical investigations show that the increase of the excitation amplitude can reduce the amplitudes of steady-state responses. We can not find this kind of results in linear systems.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.11a
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• pp.113-114
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• 2022

This study demonstrates the performance of flexible surface wave resonators in spaces on a ship to overcome environmental limits like non-metallic walls where conventional surface wave resonators cannot installable. Although test results in plane structures show that the performance of conventional surface wave resonators are better than the flexible ones, the results are reversed in curved structures. Flexible surface wave resonators can be installed on metal-pipes that connects all spaces in a ship, and this will allow to build ultimate communication network all over the ship including the rooms like cabins or bridges that are enclosed in non-metallic walls.