• 지적과 국토정보
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• 제52권1호
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• pp.5-16
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• 2022

다각형 필지의 면적오차계산에 대한 일반식으로부터 직사각형 필지의 면적오차계산식을 도출하고 관련 법률 시행령에서 정하고 있는 면적오차계산의 상수항 0.026² × M(축척분모)이 갖는 의미를 분석하였다. 그 결과, 현행의 면적오차 공식은 직사각형 필지모형으로서 도해측량의 특성을 적절히 반영하고 있으나, 정량적으로는 면적오차를 비교적 크게 허용한다는 것을 알 수 있었다. 또, 면적이 같더라도 필지의 형상에 따라 정사각형 필지보다 50% 더 많은 면적오차가 산출될 수 있다는 문제, 필지 분할시 허용면적오차가 달라져야 하는 문제 등을 파악하였다. 이와 더불어, 본 연구에서 도출한 면적오차계산식으로써 지적측량의 관점에서 문제를 한꺼번에 해결할 수 있는 방안을 제시하였다. 즉, 필지의 크기와 형상을 반영하는 문제, 측량의 정확도를 반영하는 문제, 도해측량과 수치측량을 구분할 필요 없이 단일의 면적오차계산식을 채택하는 문제에 대한 해결책이다. 이들 문제를 해소하는 새로운 면적오차계산식의 채용은 많은 관련 요소들의 개선을 촉진하여 선진적 지적제도로의 발전을 강화할 것이다.

• 해양환경안전학회지
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• 제20권4호
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• pp.451-460
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• 2014

본 연구에서 해양플랜트 구조물에 주로 사용하고 있는 알루미늄 합금 A6082-T6의 재료특성을 반영한 사각형 판에 대한 패치 로딩의 구조 안정성 문제를 검토하였다. 구조 안정성 문제를 검토 시 네 가지 패치 로딩 형태와 종횡비 효과, 주변지지조건을 적용하여 임계 탄성 좌굴하중을 산출하였다. 고유치 좌굴해석 간 사용한 요소는 4절점 쉘요소 shell181을 적용하였다. 패치 로딩을 받는 판은 균일 축 압축하중과 비교 시 상이한 탄성 좌굴거동이 발생되는 것을 관찰할 수 있었으며 하중형태와 위치, 종횡비 효과 등과 같은 변수에 대해 상당히 영향을 받고 있는 것을 확인할 수 있다. 또한, 종횡비(a/b) 1.0, 하중길이(${\gamma}b$) 200 mm 단순지지 사각형 판에서 패치 로딩 형태에 따른 임계 탄성좌굴하중은 67 %(하중 I), 119 %(하중 II), 76 %(하중 III), 160 %(하중 IV)이 각각 산출되었으며 하중 I과 III은 하중 II와 IV보다 훨씬 더 탄성 좌굴거동에 강한 것으로 판단할 수 있다.

• 한국전자파학회논문지
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• 제29권4호
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• pp.277-284
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• 2018

본 논문은 향후 투명 디스플레이, 스마트글래스(smart glass) 등의 그 활용도가 증가 추세에 있는 투명전극과 관련된 논문이며, 본 논문에서는 투명 안테나 등의 투명 고주파 수동소자 설계 시, 투명 디스플레이 등에 가장 많이 사용되고 있는 ITO(Indium-Tin-Oxide)을 이용한 박막형(thin film type) 투명전극의 낮은 전기적 특성(면저항>$5({\Omega}/sq)$)으로 인한 성능저하를 개선하고자, 고주파 소자에 가장 일반적으로 사용되는 도체인 구리선(copper wire)으로 구현되는 정방형 메탈메쉬(square metal mesh)를 이용하여 투명전극을 구현하고, 이를 기본 단위로 하여 투명 패치 안테나를 구현하였고, 그 성능을 비교 분석하였다. 본 논문에서는 투명전극의 기본 설계 블록인 정방형 메탈메쉬의 광학적 특성(광 투과도) 및 전기적 특성(면저항)을 측정 및 분석하였고, 이를 이용하여 투명 패치 안테나를 설계, 측정, 분석하였다. 또한, 정방형 메탈메쉬는 광 투과도를 높이기 위해 얇은 구리선(w=0.2 mm)을 사용하였으며, 망(mesh) 크기(l=1, 2 mm)에 따른 광 투과도와 안테나 성능(방사이득, 방사패턴)과의 관계를 분석하였다. 투명 안테나 성능 측정 결과, 안테나 성능은 정방형 메탈메쉬의 광학적 특성과 반비례하며, 실제 활용 시에는 광학적 특성, 전기적 특성, 제작비용을 종합적으로 고려하여, 응용에 따른 투명 안테나의 활용이 필요하다.

• Advances in concrete construction
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• 제2권3호
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• pp.177-192
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• 2014

One of the main applications of FRP composites is confining concrete columns. Hence identifying the cyclic and monotonic stress-strain behavior of confined concrete columns and the parameters influencing this behavior is inevitable. Two significant parameters affecting the stress-strain behavior are aspect ratio and corner radius. The present study aims to scrutinize the effects of corner radius and aspect ratio on different aspects of stress-strain behavior of FRP confined concrete specimens (rectangular, square and circular). Hence 44 FRP confined concrete specimens were tested and the results of the tests were investigated. The findings indicated that for specimens with different aspect ratios, the relationship between the ultimate stress and the corner radius is linear and the variations of the ultimate stress versus the corner radius decreases as a result of an increase in aspect ratio. It was also observed that increase of the corner radius results in increase of the compressive strength and ultimate axial strain and increase of the aspect ratio causes an increase of the ultimate axial strain but a decrease of the compressive strength. Investigation of the ultimate condition showed that the FRP hoop rupture strain is smaller in comparison with the one obtained from the tensile coupon test and also the ultimate axial strain and confined concrete strength are smaller when a prism is under monotonic loading. Other important results of this study were, an increase in the axial strain during the early stage of unloading paths and increase of the confining effect of FRP jacket with the increase and decrease of the corner radius and aspect ratio respectively, a decrease in the slope of reloading branches with cycle repetitions and the independence of this trend from the variations of the aspect ratio and corner radius and also quadric relationship between the number of each cycle and the plastic strain of the same cycle as well as the independence of this relationship from the aspect ratio and corner radius.

• 한국조경학회지
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• 제28권2호
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• pp.71-84
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• 2000

In this study, design characteristics of Village Parks in Seoul are investigated through an analysis of structuring themes expressed in spatial design. The goals and objectives of this study are: to emphasize the significance of design themes; and to demonstrate an approach to the design of landscapes through an analysis of structuring themes. For conducting this study, geometric forms and naturalistic forms were examined first. That is, the following 15 structuring themes were examined, as guiding themes: the 90$^{\circ}$rectangular theme; the 45$^{\circ}$/90$^{\circ}$angular theme; the 30$^{\circ}$/60$^{\circ}$ angular theme; circles on circle; concentric circles and radii; arcs and tangents; circle segments; the ellipse; the spiral; the meander; the free ellipse and scallops; the free spiral; the irregular polygon; the organic edge; and clustering and fragmentation. Forty five Village Parks in Seoul, built between 1996 and 1997, were analyzed through these 15 structuring themes. An analysis of Village Parks was conducted by the following two categories: land shape and structuring themes; and design directions and structuring themes. The research results are as follows; 1) Geometric forms are more frequently applied than naturalistic forms. 2) Regardless of land shape, geometric forms derived from simple primary shapes, the square and the circle, are frequently used. And the meander and the irregular polygon among naturalistic forms are frequently used. 3) Regarding design directions and structuring themes, design concepts, symbolic meanings and spatial forms are, to some degree, integrated. 4) The spiral is not applied among geometric forms. And the meander and the irregular polygon, as naturalistic forms, are frequently utilized. Research findings obtained from this study could be used in the designing of future Village Parks. For a profound study, future, research is needed in two-dimensional plans and three-dimensional elements of Village Parks.

• 한국의학물리학회지:의학물리
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• 제13권1호
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• pp.21-26
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• 2002

블록을 사용한 부정형 전자선 조사면에서의 선량율(relative output factor, ROF)을 계산하는 전자선 알고리듬을 개발하고, 측정값과 계산값을 비교하여 알고리듬을 평가하였다. 전자선의 선량은 산란판, 전자선 cone 등 모든 요소를 고려한 1차선 부분과 블럭에 의한 2차선의 합으로 표시할 수 있다고 가정하였으며, 1차선은 가우스 분포를, 2차선은 거리역제곱 법칙만을 따른다고 가정하였다. 2차선 블럭 산란에 의한 각 분포는 고려하지 않았다. 이런 방법으로 전자선의 ROF를 유효 SSD, 1차선 분포 표준편차, 2차선 발생율 등 3가지의 인자만을 이용하여 선량율을 계산할 수 있는 단순한 방식을 고안하였다. 6, 9, 12, 16, 20 MeV의 전자선을 사용하여 이 모델을 검증하였다. 측정은 항상 개방 조사면의 선량 최대지점 깊이에서 실시하였으며 다양한 정사각형 치료면 측정으로 3개의 인자를 구할 수 있었다 직사각형 조사면과 부정형 조사면에 대하여 이 모델을 이용한 계산값과 측정값의 차이는 평균 1.0％이내였으며, 최대 2.1％를 넘지 않았다. 본 연구에서 개발한 알고리듬은 필요한 인자가 3개이면서 매 전자선 콘마다 5∼6회 측정으로 구할 수 있어서 임상 적용에 편리하며, 계산 결과가 정확하여 특이 오차를 보이는 유형에 관한 보완 연구를 수행하면 임상에 사용할 수 있음을 보였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.276-279
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• 2004

Plasma enhanced chemical vapor deposition (PECVD) of silicon nitride (SiN) is a proven technique for obtaining layers that meet the needs of surface passivation and anti-reflection coating. In addition, the deposition process appears to provoke bulk passivation as well due to diffusion of atomic hydrogen. This bulk passivation is an important advantage of PECVD deposition when compared to the conventional CVD techniques. A further advantage of PECVD is that the process takes place at a relatively low temperature of 300t, keeping the total thermal budget of the cell processing to a minimum. In this work SiN deposition was performed using a horizontal PECVD reactor system consisting of a long horizontal quartz tube that was radiantly heated. Special and long rectangular graphite plates served as both the electrodes to establish the plasma and holders of the wafers. The electrode configuration was designed to provide a uniform plasma environment for each wafer and to ensure the film uniformity. These horizontally oriented graphite electrodes were stacked parallel to one another, side by side, with alternating plates serving as power and ground electrodes for the RF power supply. The plasma was formed in the space between each pair of plates. Also this paper deals with the fabrication of multicrystalline silicon solar cells with PECVD SiN layers combined with high-throughput screen printing and RTP firing. Using this sequence we were able to obtain solar cells with an efficiency of 14% for polished multi crystalline Si wafers of size 125 m square.

• Computers and Concrete
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• 제23권1호
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• pp.61-68
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• 2019

This paper presents a computational rational model to predict the ultimate and optimized load capacity of reinforced concrete (RC) beams strengthened by a combination of longitudinal and transverse fiber reinforced polymer (FRP) composite plates/sheets (flexure and shear strengthening system). Several experimental and analytical studies on the confinement effect and failure mechanisms of fiber reinforced polymer (FRP) wrapped columns have been conducted over recent years. Although typical axial members are large-scale square/rectangular reinforced concrete (RC) columns in practice, the majority of such studies have concentrated on the behavior of small-scale circular concrete specimens. A high performance concrete, known as polymer concrete, made up of natural aggregates and an orthophthalic polyester binder, reinforced with non-metallic bars (glass reinforced polymer) has been studied. The material is described at micro and macro level, presenting the key physical and mechanical properties using different experimental techniques. Furthermore, a full description of non-metallic bars is presented to evaluate its structural expectancies, embedded in the polymer concrete matrix. In this paper, the mechanism of mechanical interaction of smooth and lugged FRP rods with concrete is presented. A general modeling and application of various elements are demonstrated. The contact parameters are defined and the procedures of calculation and evaluation of contact parameters are introduced. The method of calibration of the calculated parameters is presented. Finally, the numerical results are obtained for different bond parameters which show a good agreement with experimental results reported in literature.

• Structural Monitoring and Maintenance
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• 제5권3호
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• pp.391-416
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• 2018

The purpose of this article is to strengthen concrete structures using buckling and non-buckling braces. Connection plates are modeled in three shapes including the effect of 1.5t hinge zone length, 2t one and without the zone (1.5t-CP, 2t-CP and WCP). According to the verification performed with ABAQUS software, the connection plates which are superior in ductility and strengthening are found. The results show adding steel braces in concrete moment frames increase the strength and stiffness of the structures up to about 12 and 3 times, respectively. The frame strength increased about 21 and 25 percent with considering the effect of 2t hinge length in connection plates compared to 1.5t-CPs and WCPs. Also the ductility of retrofitted frames with 2t-CP improved 2.06 times more than WCP ones. Thus, 2t-CP sample is the best choice for connecting steel braces to concrete moment frames for retrofitting them. Afterwards, optimum conditions for elemental coating in braces with no buckling are assessed. The length of concrete coatings could be reduced about 30 percent, and buckling did not occur. Therefore, the weight of restraining coating decreased, and its performance improved. It is worth noting that BRBs could be constructed with only steel materials, which have outer steel tubes too. In fact, only the square cross sections of the tube profiles are appropriate for removing the filler concrete, and the rectangular ones are prone to buckle around their weak axis.

• 한국분말재료학회지
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• 제20권5호
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• pp.355-358
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• 2013

Micro trench structures are applied in gratings, security films, wave guides, and micro fluidics. These micro trench structures have commonly been fabricated by micro electro mechanical system (MEMS) process. However, if the micro trench structures are machined using a diamond tool on large area plate, the resulting process is the most effective manufacturing method for products with high quality surfaces and outstanding optical characteristics. A nonferrous metal has been used as a workpiece; recently, and hybrid materials, including polymer materials, have been applied to mold for display fields. Thus, the machining characteristics of polymer materials should be analyzed. In this study, machining characteristics were compared between nonferrous metals and polymer materials using single crystal diamond (SCD) tools; the use of such materials is increasing in machining applications. The experiment was conducted using a square type diamond tool and a shaper machine tool with cutting depths of 2, 4, 6 and 10 ${\mu}m$ and a cutting speed of 200 mm/s. The machined surfaces, chip, and cutting force were compared through the experiment.