• Journal of Korean Society of Steel Construction
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• v.21 no.5
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• pp.527-536
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• 2009

The purpose of this experimental study was to investigate the block shear fracture behavior and curling effect on a single shear-bolted connection in thin-walled carbon steel fabricated with four bolts. The specimens that fail by block shear were planned to have a constant dimension of the edge distance perpendicular to the loading direction, bolt diameter, pitch, and gage. The main variables of the specimens were plate thickness and end distance parallel to the loading direction. A monotonic tensile test was carried out for the bolted connections, and the ultimate behaviors, such as the fracture shape, ultimate strength, and curling, were compared with those that had been predicted using the current design specifications. The conditions of curling occurrence in terms of plate thickness and end distance were also investigated, and the strength reduction due to curling was considered.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.11 s.353
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• pp.14-18
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• 2006

Optical interferometer is used for various optical measurement fields in optical metrology and biomedical measurements. In an optical interferometer, optical delay line has to change the optical path length of a reference arm to match with that of a sample in and it's speed was limited by reference arm movement speed. In this paper, we proposed an all-fibered RSODRapid Scanning-speed Optical Delay) without any mechanical movement, and we applied this system to optical interferometer. Experimental setup is consist of pulse laser source (center wavelength 1304nm, pulse width 30ps, repetition rate 10GHz), two phase modulators and dispersive shifted fiber. As experimental results, we obtain the maximum time delay of 11ps at 10MHz repetition rate, and it is easily tuneable the time delay by modulation frequency and modulation voltage.

• Journal for History of Mathematics
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• v.20 no.2
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• pp.1-18
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• 2007

In the middle of 19th century, Chosun mathematicians Nam Byung Gil(南秉吉) and Lee Sang Hyuk(李尙爀) studied mathematical structures developed in Song(宋) and Yuan(元) eras on top of their early studies on Jiu zhang suan shu(九章算術) and Shu li jing yun(數理精蘊). Their studies gave rise to a momentum for a prominent development of Chosun mathematics in the century. In this paper, we investigate Nam Byung Gil's JipGoYunDan(輯古演段) and MuIHae(無異解) and then study his theory of equations. Through a collaboration with Lee, Sang Hyuk, he consolidated the eastern and western structure of theory of equations.

• 유학연구
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• v.43
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• pp.165-192
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• 2018

이 논문은 『주역참동계고이(周易參同契考異)』를 주희의 철학에서 고립된 영역으로 간주하는 대신, 주희의 삶의 후반기에 있어 그의 사유, 특히 그의 철학의 핵심 개념 인 리(理)에 관한 사유와 관련하여 고찰했다. 『참동계』는 우주론이나 선천역학(先天易學)과 관련이 있지만, 『참동계』의 저자인 위백양(魏伯陽)은 『주역』의 해석이 아니라, 연단술의 기초를 확립하기 위해 음양 개념과 선천역학의 괘상 형성 원리를 빌렸을 뿐이다. 그러므로 우주론과 선천역학과의 관계는 간접적인 것이다. 주희에 따르면, 연단술이 근거하고 있는 『참동계』는 과학과 자연학의 공통 기반으로서 리에 기초하고 있다. 이런 맥락에서, 그는 리의 기초 위에서 자연학으로서의 외단술과 내단술을 정립하려고 했다. 주희에 따르면, 외단술은 도가의 일원론에서 일자(一者)와 같은 종류의 물질로 만들어진 단약을 찾는 방법이다. 주희는 단약이 영원한 존재와 동류로 구성되어야 함을 인정하지만, 기본적으로 외단술과 일원론을 이기이원론의 관점에서 비판한다. 또한 주희는 이기이원론에 기초하여 내단술을 재해석한다. 당시 내단을 수행함으로써 불사의 존재로 인정되던 선인(仙人)은 사실 불사의 존재가 아니라고 한다. 주희는 수명의 한계 내에서 내단의 호흡술을 통해 기의 발산을 조금 지연시킬 가능성은 인정하지만, 내단은 외단과 마찬가지로 기의 양생(養生)에 지나지 않는다고 주장한다. 그러나 양심(養心)은 마음속 리에 기초한 불사관의 새로운 전망을 가능하게 한다. 말하자면, 기의 양생과 달리 리와 관련된 자기수양은 일종의 불사와 영생에 관련된다.

• Journal of Korean Society of Steel Construction
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• v.26 no.1
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• pp.43-53
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• 2014

A single plate connection(SPC) consists of a plate welded to the columns and bolts connected to the beam web. The SPC is widely used for a simple shear connection of steel structure because it is easy-to-fabricated, easy-to-installed and economical. The conventional SPC is used for 2 to 12 bolts in a single vertical row. It is designed to limit the plate thickness by bolt diameter to obtain flexible and ductile connections. The design strength for eccentric shear shall be the lesser of the shear strength of bolts or bearing strength of plate and when the design strength is decided by edge distance failure, the results can be very conservative. Although the research on special solution for 'weak-plate/strong-bolt' model with 2 to 4 bolts has been conducted by L. S. Muir, and W. A. Thonton, 2004, study on generalized design procedures did not conduct. This study proposed design procedure for evaluation of the design strength of eccentric shear bolt groups on a single plate connection based on the actual edge distance and the direction of bolt reaction forces by using elastic vector method(EVM) and instantaneous center of rotation method(ICM).

• The Science & Technology
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• v.23 no.2 s.249
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• pp.45-47
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• 1990

• Journal of Korea Ship Safrty Technology Authority
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• v.6
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• pp.22-28
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• 2001

• Journal of Korean Society of Steel Construction
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• v.10 no.4 s.37
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• pp.601-613
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• 1998

This paper reports the first-of-its-kind free vibration solutions for sectorial plates having re-entrant corners causing stress singularities when the circular edge is either clamped or simply supported. The Ritz method is employed with two sets of admissible functions assumed for the transverse vibratory displacements. Accurate frequencies and normalized contours of the transverse vibratory displacement are presented for the spectra of sector angles.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.4
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• pp.861-864
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• 2005

In this paper, we system the system design and numerical analysis of the ultrafast optical delay line using by optical phase modulator. The numerical analysis carried out with 1310nm, lops laser and electro-optic phase modulator. As the results of numerical analysis, we show a scanning rate of 0.5 GHz and a delay range of 19.0ps. Compare with mechanical delay line, the optical delay line has a high scanning speed and a high repetition rate.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.438-440
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• 2005

광위상변조기를 이용하여 OCT용 초고속 광지연단을 설계하고 수치해석을 수행하였다. 수치해석은 electro-optic 위상 변조기에 1310nm, 10ps의 펄스폭을 갖는 레이저 광원을 적용하여 수행하였다. 수치해석결과로 500MHz의 변조 주파수일때 19ps의 시간 지연을 얻었으며, 이는 기존의 기계적 검출방식(수십kHz)의 OCT장치에 비해 1000배이상 빠른 검출이 가능할 것으로 예상된다.