• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.159-169
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• 2000

본논문에서는 강섬유 철근 콘크리트 보(SFRC) 의 감쇄 거동에 대해서 실험적인 방법과 수치 해석적인 방법으로 연구를 수행하였다 SFRC는 보다 향상된 에너지 소산능력으로 일반 철근 콘크리트보에 비하여 뛰어난 감쇄 거동을 보인다. 감쇄거동은 종방향 철근비강섬유의 형태와 부피 콘크리트 강도 응력 수준등에 의해 영향을 받는다 SFRC보의 감쇠는 다양한 수준의 균열상태에서의 동적실험 데이터를 통하여 평가하였다 곡률과 감쇠의 관계식에 기초한 유한요소 프로그램(TICAL) 이 개발되었으며 0.44%의 강섬유를 혼입한 보의 경우 5-35%의 감쇠비 증가를 보였다

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.2
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• pp.59-66
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• 2003

A novel application of nano-technology in the field of engineering, called colloidal damper, is investigated. This device is complementary to the hydraulic damper, having a cylinder-piston construction. Particularly for colloidal damper, the hydraulic oil is replacedby a colloidal suspension, which is consisted from a nano-porous matrix with controlled architecture and a lyophobic fluid. In this experimental work, the porous matrix is composed from silica gel, with labyrinth architecture, coated by organo-silicones substances in order to achieve a hydrophobic surface. Water is considered as associated lyophobic fluid. The colloidal damper test rig and the measuring technique of the hysteresis are described. the influence of the hydrophobicity level upon the colloidal damper hysteresis is investigated, for silica gels with similar pores distribution. A certain desired shape of the hysteresis can be achieved by employing mixture of silica gels with different level of hydrophobicity and/or architecture. With these results, it is believed that the proposed damper can be designed and be applied to the desired structure.

• Journal of the Korean Ceramic Society
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• v.40 no.3
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• pp.286-292
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• 2003

In this study, new shock absorbing system was proposed using silica gel particles according to the nano-technology. For the design and real application of the proposed damper, an experimental investigations are carried out using colloidal damper, which is statically loaded. The porous matrix is composed from silica gel(labyrinth architecture), coated by organo-silicones substances, in order to achieve a hydrophobic surface. Water is considered as associated lyophobic liquid. Reversible colloidal damper static test rig and the measuring technique of the static hysteresis were described. Iufluence of the water volume and particle diameters upon the reversible colloidal damper hysteresis was investigated. Also, influence of the relaxation time on the hysteresis of the damper was investigated. As a result, the proposed new shock absorbing damper is proved as an effective one, which can be replaced for the conventional hydraulic damper.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.60-61
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• 2002

Laser-induced incandescence (LII) 측정법은 조사된 레이저에 의하여 입자가 가열됨에 따라서, 그 온도에 상응하는 흑체복사의 시간적 감소추이가 입자의 크기에 따라서 달리 나타나는 것을 이용하여 입자의 크기를 측정하는 방법이다. LII 감쇄법은 레이저에 의하여 가열된 입자의 에너지 균형 상관식에서 입자의 크기가 클수록 신호의 감쇄속도가 느리고, LII 신호의 감쇄비가 실험적으로 입자의 크기에 비례한다는 사실을 이용하여 연소진단에 응용되어 왔다. (중략)

• Journal of the Korea Concrete Institute
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• v.14 no.5
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• pp.718-725
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• 2002

A wall type friction damper is newly Proposed in this paper to improve the performance of R/C framed structures under earthquake loads. Although traditional dampers are usually placed as bracing members, the application ot bracing-type dampers into R/C structures is not as simple as those of steel structures due to the connection between R/C members and dampers and the stress concentration in connection region. Proposed damper is consisted of Teflon-sheet slider and R/C shear wall. The damper can also avoid stress concentration and reduce P-Δ effect. To evaluate the performance of proposed damper, nonlinear dynamic analyses are carried on 10 story and 3 bay R/C structures with numerical model for the damper. It is shown that the damper reduces the inter-story drifts and the time-historic responses; especially the damper prevents from forming plastic hinges on the lower columns.

• Electronics and Telecommunications Trends
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• v.18 no.2 s.80
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• pp.67-78
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• 2003

모든 RF 통신 시스템에서 사용되는 마이크로파 필터는 통과 대역에서 에너지를 전달하고, 저지 대역에서 에너지를 감쇄시키는 역할을 한다. 주파수 사용 효율을 높이기 위해서 대역내 평탄도 및 군지연 특성이 우수하고, 대역외에서 높은 감쇄를 갖는 필터 개발에 많은 연구가 이루어졌다. 본 고에서 필터 개발에 필수적인 전달 함수 특성 및 결합 구조에 관하여 고찰한다.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.2141-2145
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• 2008

Three kind of system composed with buoyant flap hinged at the sea floor are modeled experimentally. The mechanically coupled system provides shelter by reflecting incident waves and by attenuating wave energy through structural and viscous damping. The characteristics of wave reflection, transmission and dynamic angle of the flap oscillation for various conditions were investigated. The structure can minimize wave transmission by attaching offshore wing wall.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.05b
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• pp.111-112
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• 2003

자외선의 영역에서 에너지 흡수를 일으키는 기준 가스들을 측정하는 방법은 여러 가지가 있다. 근래에 이르러 분광학적인 방법으로 이들을 측정하는 시도가 늘어나고 있다. 유럽에서 널리 이용중인 도아즈는 현재는 위성에 응용되어 개발되고 있으며 가스의 파장에 대하여 흡수선을 이용하여 해당가스를 검출해내는 기술을 그 원리로 하고 있다. 지점 측정 방법에 대하여 많은 장점을 가지고 있으나 현재로서는 지속적으로 개발되고 있고 응용 기술의 난해함 등으로 그 응용범위가 한정되어 있다. 본 연구는 국내에서 개발된 도아즈 시스템으로부터 시정 거리를 산출하는 데 필요한 550 nm 에서의 광 감쇄도 측정을 내용으로 한다. (중략)

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.6 no.4
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• pp.57-61
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• 1995

This paper reports on a theoretical and experimental study on an effect of length between the EUT and surge generator. In the case of using 40m line, surge energy was decreased to 77% of the output of surge generator.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.2
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• pp.83-91
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• 2012

An RF energy detector for spectrum sensing in TV white space transceiver is presented. It is based on an RF active filtering technique that comprises a low-noise amplifier with a frequency-translation high-pass filtering feedfoward loop, which attenuates the unwanted sideband energy and only passes the wanted band energy. Unlike the conventional architecture, a new architecture that can attenuate both sidebands at the same time is proposed. A simplified system modeling method is presented to assess the non-ideality effects on the RF energy detector performances. System behavioral simulations demonstrate that the proposed architecture can be instrumental for realizaing a RF energy detector circuit in CMOS.