• 한국구조물진단유지관리공학회 논문집
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• 제13권1호통권53호
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• pp.169-178
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• 2009

링 형태의 강섬유 (Ring-type steel fibers: 이하 RSF)는 원형의 폐곡선 형태를 갖는 강섬유로서 선형 강섬유와는 다른 저항 메카니즘을 가지며 폐곡선으로 둘러싸인 평면에 대하여 동일한 방향성을 가지는 특성을 갖는다. 이 연구에서는 섬유의 단위투입량 $15kg/m^3$과 $30kg/m^3$의 RSF 및 선형 강섬유를 혼입한 콘크리트 패널의 휨인성을 실험, 비교하였다. 파단면에서의 RSF의 저항 형태를 규명하였으며 RSF를 혼입한 패널이 선형 강섬유를 혼입한 패널에 비하여 우수한 인성값을 나타냄이 관찰되었다. RSF에 대한 방향성을 제시하였으며 RSF를 혼입한 실험체의 경우, 보 실험체에 비하여 두께가 상대적으로 얇은 패널 실험체에서 RSF가 더 효율적으로 인성 증가에 기여함이 관찰되었다.

• 대한토목학회논문집
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• 제10권4호
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• pp.1-10
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• 1990

RILEM에서는 콘크리트의 파괴에너지를 결정하기 위하여 3점휨시험 방법을 제시하였으나, 콘크리트의 자중의 영향으로 인하여 이론치와 실험치가 잘 일치하지 않는 경향이 있다. 본 연구에서는 콘크리트의 자중의 영향을 고려하기 위하여 완전탄성체지지대로서 proving ring을 이용한 4점휨시험을 제시하였으며, 인조균열길이의 변화에 따른 콘크리트의 파괴에너지 변화를 알아보기 위하여 보의 높이에 대한 인조균열길이의 비를 0.2부터 0.6까지 변화시켜 실험을 실시하였다. 본 연구에서 제안된 4점휨 시험을 통하여 콘크리트의 파괴거동을 보다 쉽게 파악할 수 있었으며, 4점휨시험이 3점휨시험 보다 파괴역학이론에 잘 들어맞는 것을 알 수 있었다.

• 한국광학회지
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• 제5권1호
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• pp.51-59
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• 1994

네 개의 평면 반사경과 두 개의 볼록 렌즈로 구성된 Newtonian 망원경 형의 negative branch confocal unstable ring (NBCUR) 공진기를 이용한 진행파형 Nd:YAG 레이전 발진기를 설계 제작하였다. 출력경으로 scraper mirror를 사용하여 원고리형 출력광을 얻었다. 이 레이저 발진기는 22개의 광학면을 가지고 있으며 이의 광학적 시준은 등경사 간섭법에 의해 간섭무늬를 관측함으로서 해결하였다. 일방향 진행파형 레이저 발진을 이룩하기 위하여 고리형 공진기 내에 자체 설계 제작된 영구 자석형 Faraday isolator를 삽입하였고, 이에 의한 발진 효과를 검토 하였다. 전기 입력 에너지 70J에서 레이저 출력에너지 약 80mJ 이었으며, BDN 색소에 의한 수동형 Q 스위칭에 의하여 첨두 출력 0.5 MW를 얻었다.

• 한국소음진동공학회논문집
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• 제23권8호
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• pp.690-697
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• 2013

The magnets and vacuum chambers, which are the main facilities of the Pohang light source are installed on the storage-ring girders. System safety and reliability should be taken into account for the precise operating of the main facilities, so vibration analysis is essential to do this. Static and seismic analyses were performed for the design of structure considering safety, and also frequency and response spectrum analyses were performed for the precise alignment. With these results, the effects of surrounding vibration were checked. This paper explains about the design and vibration analysis of girder systems.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 D
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• pp.1546-1548
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• 1998

Dual mode ring resonators(DMRR) have been fabricated using laser ablated $YBa_2Cu_3O_{7-x}$ superconducting thin films. The transition temperature of YBCO thin films were 85 - 88 K and the film thicknesses were about 5,000 $\AA$. Dual mode ring resonators were patterned by standard photolithography process and wet-etching. Then two-layer metal thin films (Ti/Ag) have been deposited for the ground plane on the back side of substrate by e-beam and thermal evaporation. The input/output feedline angles of each resonator were $60^{\circ}$, $100^{\circ}$, $180^{\circ}$. A network analyzer was used for testing the performance of the resonators in the frequency range of 6-13 GHz at 77 K.

• Steel and Composite Structures
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• 제22권1호
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• pp.183-201
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• 2016

Perforated steel beams can be optimised by increased beam depth and the moment of inertia combined with a reduced web thickness, favouring the use of original I-section beams. The designers are often confronted with situations where optimisation cannot be carried out effectively, taking account of the buckling risk at web posts, moment-shear transfers and local plastic deformations on the transverse holes of the openings. The purpose of this study is to suggest solutions for reducing these failure risks of tested optimal designed beams under applying loads in a self-reacting frame. The design method for the beams is the hunting search optimisation technique, and the design constraints are implemented from BS 5950 provisions. Therefore, I have aimed to explore the strengthening effects of reinforced openings with ring stiffeners, welded vertical simple plates on the web posts and horizontal plates around the openings on the ultimate load carrying capacities of optimally designed perforated steel beams. Test results have shown that compared to lateral stiffeners, ring and vertical stiffeners significantly increase the loadcarrying capacity of perforated steel beams.

• 한국진공학회지
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• 제2권2호
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• pp.131-138
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• 1993

독일의 1.2GeV 전자 저장링 델타(DELTA)에 대한 초전도 비대칭 다극 위글라에 대한 연구계획이 진행 중에 있다. 본 연구에서는 이 삽입장치의 비선형 효과에 대한 영향이 연구되었다. 표준 라티스(lattice)는 고려된 오차들에 관한 빔역학적인 문제에 대해서 안정함을 보였다.

• 한국실내디자인학회논문집
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• 제13호
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• pp.203-215
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• 1997

This Study typed the roof-design in analysis of structural design of the glulam architecture, developed worldwidely, nowaday. For this, it is studied the characters of glulam as the history of glulam architectures, manufacture of glulam, shapes and section of glulam, fireproof and combution of glulam. And it is studied roof-design according to structural type of glulam roof-structure. Conclusively, types of glulam roof design typied as 1)the Simple Beam str., 2)the Multi-Joints continous Beam str. 3)the Hinge str. 4)the Rahmen str. 5)the Archi str. 6)the Grid str. 7)etc str. (Folded-plate str., Radial str., Cylinder Shell str., Ring Dome str., Geodesic Dome str., Conic Coloid Shell str., H.P Shell str. Cantilever Shell str.)

• Tribology and Lubricants
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• 제8권2호
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• pp.50-63
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• 1992

The minimum oil film thicknesses (MOFT) in the crankshaft main bearings of a 1.5 liter, L-4, gasoline engine are measured and calculated to study the dynamically loaded engine bearing. The MOFT are measured simultaneously at each of the five main bearings using the total capacitance method(TCM). To improve the reliability of the TCM, a reasonable determination method of bearing clearance is introduced and the effects of bearipg cavitation and aeration on the test results are analyzed. Also the crankshaft is grounded by means of a slip ring instead of the friction contact method to improve the test precision. The calculation is based on the model of statically determinate beam, short bearing approximation and Mobility method. From the comparison between the measured and calculated MOFT curves, it is found that a qualitative similarity exists between them, but in all cases, measured MOFT are smaller than that of calculated. The crankshaft vibration and the imbalance of the load distribution between the engine bearings have important influence upon the MOFT curve. So it is found that the calculation result from the model of the statically determinate beam has a limitation in predicting bearing performance.

• The Journal of the Acoustical Society of Korea
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• 제18권4E호
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• pp.3-9
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• 1999

Deep-water sonar transducers of FFR (Free Flooded Ring) type have been designed using a coupled FE-BEM. The proposed sonar transducers are composed of piezoelectric ceramic tubes and structural steel materials for simple fabrication. In order to have an omnidirectional beam pattern around 30kHz, a conic steel is placed below a piezoelectric tube or a steel disc is placed between two piezoelectric tubes. The dynamics of the sonar transducer is modelled in three dimensions and is analyzed with external electrical excitation conditions. Various results are available such as directivity patterns and transmitting voltage responses. The most optimal structure and dimensions of the steel material were calculated, so that the beam patterns of the sonar transducers had +/- 3dB omnidirectivity at 30kHz.