• 대한환경공학회지
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• 제34권3호
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• pp.168-176
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• 2012

2011년 3월에 대구광역시의 대형유통업소주차장을 대상으로 총 48개의 먼지시료를 채취하여 100 ${\mu}m$ 이하로 걸러서 산추출한 후 ICP로 14개 원소를 분석하였다. 미량원소성분 중 Ca, Fe, K, Mg, Mn, Na, V는 자연적 발생원의 영향을, 그리고 Cd, Cr, Cu, Ni, Pb, Zn은 인위적 발생원의 영향을 받는 것으로 추정된다. 미량원소성분의 농도는 자연적 발생원 성분이 인위적 발생원 성분보다 뚜렷하게 높았고, 인위적 발생원 성분은 지상옥상이 지상실내와 지하실내보다 농도가 높았다. 미량원소성분의 조성백분율은 인위적 발생원 성분에 비해 자연적 발생원 성분이 대부분을 차지하였고, 인위적 발생원 성분은 지상옥상이 지상실내와 지하실내보다 함유율이 높았다. 주차장은 유해중금속오염이 거의 없는 수준을 보였고, 지상옥상은 지상실내와 지하실내보다 중금속오염도가 높았다. 미량원소성분간의 상관성은 지상옥상이 지상실내와 지하실내보다 양호한 상관성이 많았고, 인위적 발생원 성분은 주차장연수와 주차밀도와도 상관성이 양호하였다.

• Design & Manufacturing
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• 제14권4호
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• pp.65-70
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• 2020

Partial reinforcement of sheet metal parts with CFRP patch is a technology that can realize ultra-lightweight body parts while overcoming the high material cost of carbon fiber. Performing these patchworks with highly productive press equipment solves another issue of CFRP: high process costs. The A-pillar is the main body part and has an undercut shape for fastening with other parts such as roof panels and doors. Therefore, it is difficult to bond CFRP patches to the A-pillar with a general press forming tool. In this paper, a flexible system that applies uniform pressure to complex shapes using ceramic particles and silicone rubber is proposed. By benchmarking various A-pillars, a reference model with an undercut shape was designed, and the system was configured to realize a uniform pressure distribution in the model. The ceramic spherical particles failed to realize the uniform distribution of high pressure due to their high hardness and point contact characteristics, which caused damage to the CFRP patch. Compression equipment made of silicone rubber was able to achieve the required pressure level for curing the epoxy. Non-adhesion defects between the metal and the CFRP patch were confirmed in the area where the bending deformation occurred. This defect could be eliminated by optimizing the process conditions suitable for the newly developed flexible system.

• 국제초고층학회논문집
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• 제9권2호
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• pp.113-125
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• 2020

Beginning in the late 19th century, construction of skyscrapers spread throughout Chicago, New York City, and then the world as demand of space in buildings and increase of cost of land. With this change curtain wall systems have evolved to be more visually complex; these unique profiles of the skyscraper became powerful images and symbols of our cities. A curtain wall is defined as usually aluminum-framed wall containing in-fills of glass and metal panels. The framing is attached to the building structure and does not carry the floor or roof loads of the building.

• Structural Engineering and Mechanics
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• 제46권3호
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• pp.387-402
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• 2013

A dynamic load protocol has been used to experimentally simulate fatigue behavior in cold-formed metal panels with screwed connections under wind loading. The specific protocol adopted is an adaptation of SIDGERS, originally developed for non-metallic membranes, which is composed of levels each under increasing load values. A total of 19 tests were performed on 3.35 m long by 0.91 m wide panels, identified as Type B-wide rib and Type E, both with screw connections at the edge and at the center, thus conforming two-span specimens. In some configurations the panels were fixed at the valleys, whereas crest-fixed connections were also investigated. Reinforcing the connections by means of washers was also investigated to evaluate their efficiency in improving fatigue capacity. The experimental results show maximum load capacities in improved connections with washers of approximately twice of those with classical connections.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2000년도 춘계학술대회논문집
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• pp.159-162
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• 2000

Wrinkles and shape distortions are generated during the forming of B-pillar(or center pillar) which is a component of the automobile side-frame. The stretch flanging modes at the joining part of the B-pillar and the roof-rail or the side-still give rise to forming problems when taior-welded blanks are applied to the side-frames. The authors simplified B-pillar lower part to T shaped section to investigate the forming behaviors. Three of die step locations and two of blank types were tested to show the effects of weld line locations and edge conditions on he forming of tailor welded blanks. The heights of body wrinkles and the strain distribution in the stretch flanged area were measured and compared.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1553-1554
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• 2015

건축물의 외장재로 널리 쓰이는 금속지붕패널을 피뢰시스템의 자연적 구성부재로 적용하기 위해 KS C IEC 62305-3 규격을 바탕으로 검토하였다. 금속패널을 피뢰시스템의 자연적 구성부재로 적용할 수 있다면 피뢰시스템을 설치하기 위해 건축물의 미관을 해치지 않을 뿐 아니라 경제성과 시공성도 확보할 수 있다. 이를 위해 KS C IEC 62305-3에서 규정한 자연적 구성부재의 조건을 확인하고 LPL I~IV 등급의 임펄스전류를 인가하여 적용성 여부를 확인하였다.

• Wind and Structures
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• 제12권4호
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• pp.383-400
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• 2009

Low rise building roofs can be subjected to large fluctuating pressures during a tropical cyclone resulting in fatigue failure of cladding. Following the damage to housing in Tropical Cyclone Tracy in Darwin, Australia, the Darwin Area Building Manual (DABM) cyclic loading test criteria, that loaded the cladding for 10000 cycles oscillating from zero to a permissible stress design pressure, and the Experimental Building Station TR440 test of 10200 load cycles which increased in steps to the permissible stress design pressure, were developed for assessing building elements susceptible to low cycle fatigue failure. Recently the 'Low-High-Low' (L-H-L) cyclic test for metal roofing was introduced into the Building Code of Australia (2007). Following advances in wind tunnel data acquisition and full-scale wind loading simulators, this paper presents a comparison of wind-induced cladding damage, from a "design" cyclone proposed by Jancauskas, et al. (1994), with current test criteria developed by Mahendran (1995). Wind tunnel data were used to generate the external and net pressure time histories on the roof of a low-rise building during the passage of the "design" cyclone. The peak pressures generated at the windward roof corner for a tributary area representative of a cladding fastener are underestimated by the Australian/New Zealand Wind Actions Standard. The "design" cyclone, with increasing and decreasing wind speeds combined with changes in wind direction, generated increasing then decreasing pressures in a manner similar to that specified in the L-H-L test. However, the L-H-L test underestimated the magnitude and number of large load cycles, but overestimated the number of cycles in the mid ranges. Cladding elements subjected to the L-H-L test showed greater fatigue damage than when experiencing a five hour "design" cyclone containing higher peak pressures. It is evident that the increased fatigue damage was due to the L-H-L test having a large number of load cycles cycling from zero load (R=0) in contrast to that produced during the cyclone.

• 건축역사연구
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• 제16권4호
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• pp.77-93
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• 2007

According to documentary records Woljeong-gyo(stone bridge) is built in 760(Silla the 35th King Gyeongdeok 19) and used as original function until 1280(Goryeo the 25th King Chungryeol 6) as Chunyang-gyo. But in those days "Donggyeongjapgi" was published in 1669(Joseon Hyeonjong 10) we assume that it was lost its original function. There are four pier in the type of a ship with the same distance in the middle of river. We can see it is the site of bridge as parts of stonework of bridge are remained. In 1975 the abutments and piers are surveyed and in 1984 stone investigation twice and excavation three times which were to plan restoration were done. Now the restoration of abutments both ends are worked. For restoration of Woljeong-gyo studied documentary records and excavation recoeds were collected and examined. It helped to see the bridge in southern China twice to restore the bridge. Unearthed articles such as yeonham(a kind of member to support roof tiles) and giwa(roof tile) gave decisive clues to assume upper structure of the bridge and from Chinese bridges are helped to type of the bridge. It is certain Woljeong-gyo was ranggyo which means that upper structure was made with wooden members and the stone piers shaped of a ship below and near the abutments both ends another buildings were. Youngjocheok(the architectural measure) of this bridge is similar to gokcheok(the metal measure, 301.84mm) used now that the length of piers is 46choek(尺), the width of that is 9choek(尺), the length between two piers is 42choek(尺), the length between abutment and pier is 38choek(尺). Also we can see that entirely the length of the bridge is 210choek(尺), width is 40choek(尺).

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2009년도 추계 학술논문 발표대회
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• pp.113-116
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• 2009

This study analyzed fire-resistant characteristics according to changes in repair methods of PFH mixed high-strength concrete roof structures having undergone fire damage. The results of the study are as follows. First, as a repulsive characteristics of structures, the remaining repulsion was shown to increase following fire-resistance tests according to increases in depth of coverings. The results of the relationship between depth of coverings and remaining repulsion rates following fire-proofing tests showed a high correlation. At a covering depth of 67.3mm, remaining repulsion rate was estimated to be 100%. For fire-resistant characteristics following repairs of structure, as for spalling, severe separation was shown in the case of general plaster while general plaster + Metal Lath showed overall superior spalling prevention. For internal structure temperatures, general plaster showed max temperatures of 705℃, average temperatures of 636℃ while general plaster + metal lath showed max temperature of 660℃ and average temperature of 520℃, demonstrating lower temperature distributions than use of only general plaster. In conclusion, after removing the covering of structures damaged due to high temperatures of fires within high-strength concrete installations, the use of fire-resistant mortars and applying metal laths on surfaces of general plaster will provide superior fire-resistance performance in the occurrence of a 2nd fire.

• 한국습지학회지
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• 제21권2호
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• pp.173-180
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• 2019

본 연구는 도로, 주차장 및 지붕에서 발생된 TSS와 중금속의 거동을 분석하기 위해 수행되었다. 강우시 도로, 주차장, 지붕에서 발생되는 중금속은 입자상 물질(TSS)에 부착되어 이동된다. 이는 TSS 부하량과 Cr, Fe, Cu 및 Pb의 입자상 중금속 및 용존성 중금속의 부하량의 상관관계로 판단 가능하다(r =0.52~0.73, p <0.01). 일반적으로 도로 및 주차장에서 발생된 TSS 및 중금속은 지붕에 비해 더 높은 것으로 분석되었는데, 이는 차량에 의해 중금속이 많이 발생하며, 집수면적 또한 도로 및 주차장이 넓기 때문으로 보여진다. 첨두유출발생시까지 TSS 부하량의 65~75%가 유출되는 것으로 나타났으며, 이는 인근 수계로 유출되는 TSS를 제거하기 위해서는 첨두유출을 제어하는 것이 가장 효과적인 것을 의미한다. 또한 비용경제적인 LID 시설의 규모를 산정하기 위해 시설의 적정 크기(시설의 표면적/배수구역 면적)에 따른 TSS와 중금속 제거율을 평가하였다. 본 연구는 LID 시설의 설계시 참고 가능한 기초데이타로 중요한 의미가 있는 것으로 사료된다.