• Journal of electromagnetic engineering and science
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• 제5권1호
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• pp.21-25
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• 2005

In this paper, a new method is suggested to improve the frequency responses of dual-mode waveguide-filters that employ cross-shaped slots. In accordance with this method, regarding one cross-shaped slot between two cavities, the horizontal(vertical) mode in one cavity can be designed to influence far less the vertical(horizontal) mode in cavity. Therefore, it improves the overall performances. A 4th-order dual-mode filter is taken as an example and it validates the method.

• 한국통신학회논문지
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• 제17권8호
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• pp.816-822
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• 1992

본 논문에서는 중심코어가 사다리꼴분포를 갖는 segmented core 단일모드 광섬유의 전파특성을 \ulcorner=1.55um에서 영분산을 만족하는 조건하에서 상대 굴절율차비의 변화에 대해 이론적으로 조사하였다. 기존의 광섬유(삼각형 굴정율, 이중형 코어)와 곡률손실을 비교한 결과 크게 감소함을 확인하였다. 그리고 코어내의 모드필드의 집속효과가 기존의 사다리꼴 굴절율 광섬유보다 28% 더 향상되었다. 기존의 삼각형 분포를 갖는 segmented core 광섬유와 비교하여 여러 장점들을 제시 하였다.

• International Journal of Precision Engineering and Manufacturing
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• 제2권3호
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• pp.11-18
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• 2001

A simple and convenient method of analysis for obtaining the individual stress intensity factors in a three-dimensional mixed mode crack is proposed. The procedures presented here are based on the path independence of J integral and mutual or two-state conservation integral, which involves two elastic fields. The problem is reduced to the determination of mixed mode stress intensity factor solutions in terms of conservation integrals involving known auxiliary solutions. Some numerical examples are presented to investigate the effectiveness and applicability of the method for a three-dimensional penny-shaped crack problem under mixed mode. This procedure is applicable to a three-dimensional mixed mode curved crack.

• 대한토목학회논문집
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• 제28권6A호
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• pp.827-833
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• 2008

이 논문은 elastica형 아치의 자유진동에 관한 연구이다. Elastica형 아치의 선형은 항상 일정한 곡선길이를 갖는 후좌굴 기둥의 정확탄성곡선을 이용하였다. 이 Elastica형 아치의 곡률항을 일반아치의 자유진동을 지배하는 미분방정식에 적용하여 고유진동수 및 진동형을 산출하였다. 수치해석 예에서는 회전-회전, 회전-고정 및 고정-고정의 지점조건을 고려하였다. 회전관성이 고유진동수에 미치는 영향을 분석하고, 아치의 높이비 및 세장비와 고유진동수와의 관계를 그림에 나타내었다. Elastica형 아치와 포물선형 아치의 고유진동수를 비교한 결과, elastica형 아치의 고유진동수가 포물선 아치의 고유진동수보다 매우 크게 나타나는 동적 특성을 보였다. 진동형의 전형적인 예를 그림에 나타내었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.223-224
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• 2006

This paper present a new disk-type piezoelectric transformer. The input side of the transformer has a crescent-shaped electrode and the output side has a focused poling direction. This transformer has multi-layered structure. The piezoelectric transformers operated m each transformer's resonance vibration mode. The electrodes and poling directions on commercialy available piezoelectric ceramic disks were designed so that the planar or shear mode coupling factor ($k_p,\;k_{15}$) becomes effective rather than the transverse mode coupling factor ($k_{31}$). The Resonance frequency is 65.22[kHz] and maximum voltage step-up ratio is 149. Multi-layered transformer has better efficiency and step-up ratio than the single-layered transformer.

• ETRI Journal
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• 제33권6호
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• pp.953-956
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• 2011

A novel dual-mode bandpass filter (BPF) using a dual spiral-shaped defected ground waveguide (DGW) resonator is proposed in this letter. The dual-mode characteristic of this filter is achieved by loading a defected T-shaped stub at the midline of the spiral-shaped DGW resonator. Also, non-orthogonal input and output feed-lines are adopted in the filter. Based on the compact DGW structure, a dual-mode BPF with central frequency of 1.5 GHz for the global positioning system is designed, fabricated, and measured. Measured results agree well with the predicted response and verify the proposed methodology.

• International Journal of Precision Engineering and Manufacturing
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• 제1권2호
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• pp.14-23
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• 2000

A numerical scheme is proposed to obtain the individual stress intensity factors in an axisymmetric crack and in a three dimensional mixed mode crack. The method is based on the path independence of J and M integral and mutual or two-state conservation integral , which involves two elastic fields. Some numerical example are presented to investigate the effectiveness and applicability of the method for and axisymmetric crack and a three dimensional penny shaped crack problem under mixed mode.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.367-370
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• 2004

This paper present a new disk-type piezoelectric transformer. The input side of the transformer has a crescent-shaped electrode and the output side has a focused poling direction. The piezoelectric transformers operated in each transformer's resonance vibration mode. The electrodes and poling directions on commercially available piezoelectric ceramic disks were designed so that the planar or shear mode coupling factor $(k_p,\;k_{15})$ becomes effective rather than the transverse meed coupling factor $(k_{31})$. A single layer prototype transformer, 26[m] in diameter and 2.0[mm] thickness, was fabricated, such as step-up ratio, power transformation efficiency and temperature were measured.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.234-235
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• 2005

This paper present a new disk-type piezoelectric transformer. The input side of the transformer has a crescent-shaped electrode and the output side has a focused poling direction. The piezoelectric transformers operated in each transformer's resonance vibration mode. The electrodes and poling directions on commercially available piezoelectric ceramic disks were designed so that the planar or shear mode coupling factor ($k_p,\;k_{15}$) becomes effective rather than the transverse mode coupling factor ($k_{31}$).

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2001년도 종합학술발표회 논문집 Vol.11 No.1
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• pp.157-160
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• 2001

본 논문에서 5.8GHz의 주파수 대역에서 사용할 수 있는 향상된 커플링 구조와 크기를 줄인 dual-mode microstrip bandpass filter를 설계하였다. 여기서 meander loop resonator를 쓰는 이유는 크기가 작고 방사 손실이 적으며 패턴이 간단하기 때문이다. 또한 이와 비슷한 특성을 갖는 ring, square patch, disk등은 불연속 성분을 가짐으로써 이중모드의 구현이 가능하다. 향상된 형태의 dual-mode microstrip bandpass filter의 변형된 T-shaped meander loop resonator를 소형으로 발전되고. 높은 선택도를 가지는 구조이다. 이 형태의 filter에서 150MHz의 bandwidth을 가지고 5.8GHz주파수를 가지는 구조로 설계하였다.