• 대한기계학회논문집A
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• 제39권1호
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• pp.95-103
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• 2015

평엔드밀 가공된 측벽 형상에 공구 형상이 미치는 영향에 대하여 알아보고자 한다. 이를 위하여, 공구 형상을 비틀림각, 절삭날 수, 직경으로 구분하여 특징지었으며, 가공면의 기하학적 특성은 서로 직교하는 이송방향 형상과 축방향 형상으로 나누어 고려하였다. 각 방향의 형상 특성은 공구와 공작물 및 절삭날과 공작물의 간섭 영역으로부터 계산한 순간 절삭면적을 바탕으로 추정하였으며, 추정의 타당성을 가공면 형상 및 배분력 측정을 통하여 검증하였다. 연구 결과, 이송방향 형상의 결함은 공구 퇴출 및 공구 경로의 곡률반경이 변하는 구간에서 나타나며, 이외의 구간에서는 축방향 형상의 결함이 주를 이루는 것이 확인되었다. 측벽의 가공정밀도를 향상시키기 위해서는, 상대적으로 직경이 작고, 비틀림각이 큰 절삭날을 많이 갖는 엔드밀을 사용하여 상향절삭 하는 것이 바람직할 것으로 추천된다.

• 한국구조물진단유지관리공학회 논문집
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• 제7권2호
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• pp.201-208
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• 2003

In domestic, bearing wall apartment building have not rectangular walls but irregular walls which are designed at walls of various cross-sectional shapes such as H-shaped, T-shaped, Box-shaped and L-shaped. In these irregular walls connected with rigid joint each other, one side walls of irregular walls is expected to show effective behavior for rigid-jointed the other side walls. Moreover, previous studies have focused on simplifying irregular walls into rectangular walls because of the complication in structural design and analysis. So studies for variables affecting behaviors of irregular walls, such as aspect ratios and compressive strength of concrete, are insufficient. The objective of this study is to evaluate the behaviors of T-shaped structural walls with different concrete compressive strengths and aspect ratios by experimental works. Results of this experimental study show that flange wall is contributed to increase the flexural strengths by the variation of concrete strengths and aspect ratios, and that it is needed to evaluate the effect width of flange wall for rational wall design.

• Journal of electromagnetic engineering and science
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• 제11권3호
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• pp.220-226
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• 2011

We have proposed a new method to accurately predict the resonance of Fabry-Perot Cavity (FPC) antennas enclosed with conducting side walls. When lateral directions of an FPC antenna are not blocked with metallic walls, the conventional technique is accurate enough to predict the resonance of the FPC antenna. However, when the FPC antenna has side walls, especially for case with only a short distance between the walls, the conventional prediction method yields an inaccurate result, inevitably requiring a tedious, time-consuming tuning process to determine the correct resonant height to provide the maximum antenna gain in a target frequency band using three-dimensional full-wave computer simulations. To solve that problem, we have proposed a new resonance prediction method to provide a more accurate resonant height calculation of FPC antennas by using the well-known resonance behavior of a rectangular resonant cavity. For a more physically insightful explanation of the new prediction formula, we have reinvestigated our proposal using a wave propagation characteristic in a hollow rectangular waveguide, which clearly confirms our approach. By applying the proposed technique to an FPC antenna covered with a partially reflecting superstrate consisting of continuously tapered meander loops, we have proved that our method is very accurate and readily applicable to various types of FPC antennas with lateral walls. Experimental result confirms the validness of our approach.

• 한국축산시설환경학회지
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• 제7권3호
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• pp.147-154
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• 2001

가축의 행동에 대한 관심이 치근 고조되고 있으며, 향후에는 가축복지법의 규제도 받게 될 실정인데 비하여 우리 나라는 아직 동물과 환경과의 관계에 대한 연구가 미진한 실정이다. 돈사의 구조적 특성은 돼지에게 여러 가지 측면에서 영향을 미쳐 생산성을 좌우하게 될 뿐만 아니라 동물복지 차원에서도 연구가 진행되어야 할 시점이다. 따라서 본 실험은 무창 육성·비육돈사에서 계절별 환기시스템에 따른 휴식공간을 파악하고자 하였으며, 또한 측벽밀폐 비율이 돼지의 배분 습성에 미치는 영향을 조사하고자 하였다. 1. 돈방 측벽밀폐율을 50%, 75%, 100% 세수준으로 하였을 때 돼지의 배분습성은 온도, 습도, 공기유속과 상관없이 일정한 지역에 배분하는 행동을 보였다. 따라서 돼지는 돈방내의 어두운 지점에서 배분하는 것으로 관찰되어 무엇보다도 조명의 영향을 받는 것으로 나타났다. 2. 측벽 밀폐율에 따른 분뇨의 배분집적 높이는 50% 일 때 10cm, 75%는 5cm 그리고 100%일 때는 3 cm가 직접 되었으며, 폭은 각각 30 cm, 25 cm, 20 cm로 나타났다. 3. 돈방의 휴식공간에서의 암모니아 농도는 각 돈방 측벽의 배분율이 50%일 때 $4.2mg/{\ell}$, 75%는 $5.1mg/{\ell}$ 그리고 100%일 때 $5.8mg/{\ell}$그리고 100% 일 때 $5.8mg/{\ell}$으로 측정되어 돈방바닥면에 분뇨가 넓게 분포되는 100%일 때 암모니아의 농도가 가장 높았다. 이것을 배분습관과 연관되어 돈방내의 어두운 부분을 최소한 줄일 경우 휴식공간에서의 암모니아 농도는 줄일 수 있는 것으로 판단되었다. 4. 요인중 돼지의 휴식공간의 위치 영향에서 환경변인은 무엇보다도 공기유속인 등 하다. 겨울철에는 0.03 m/g 지점에서 휴식을 하였으며, 여름철에는 0.24 m/g 지점에서 휴식을 취하였다. 따라서 돼지의 휴식공간은 공기의 유속에 의한 영향이 매우 큰 것으로 관찰되었다.

• 한국공간구조학회논문집
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• 제11권2호
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• pp.63-70
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• 2011

축사는 비닐하우스 다음으로 자연재해에 취약한 농촌시설물이다. 축사의 경우 측벽 없이 지붕만 있는 형태가 가장 많이 사용되고 있는데, 태풍이 불면 지붕 전제가 날아가 많은 피해가 발생하는 실정이다. 그래서 농가에서는 태풍피해예방을 위한 측벽에 윈치 커튼설치하여 피해를 예방하고 있는 실정이다. 본 논문에서는 측벽 개방에 따른 축사지붕에 위치별 풍압 계수 분포특성에 대해서 알아보고자 한다. 측벽유무에 관계없이 축사지붕면의 피크외압계수분포에서 풍향각 $0^{\circ}$로 불어오는 방향에 대해서 불리하게 작용하고 있는 것을 알 수 있다. 그러나 측벽의 유무에 따라 피크외압계수가 풍향각과 처마의 길이에 영향을 받는 것을 확인할 수 있었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1994년도 가을 학술발표회 논문집
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• pp.225-230
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• 1994

This paper concerns a case study on the design concept, analysis, construction methodology of a subway tunnel excavated in the soft ground beneath an existing building where the distance between the bottom of the building and the crown of the tunnel is separated by about 3 meters only. The silot tunnels are excavated in advance, and side reinforced-concrete walls are installed. Then, main tunnels are excavated with ring cut method. The steel ribs are installed and supported by the side walls made in advance. Between the steel ribs and the side walls, the screw jack is installed to apply prestressing so that settlement can be controlled at minimum. Various in-situ seasurements are made and compared with computed values obtained by numerical methods. By choosing this underpinning method with very caraful construction control, tunnelling projects could be finished successfully without having any damage to the building located very closely to the tunnel crown.

• Advances in Computational Design
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• 제4권3호
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• pp.251-272
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• 2019

This study performed lateral load testing on seventeen wood wall frames in two sections. Section one included eight tests studying structural foam sheathing of shear walls subjected to monotonic loads following the ASTM E564 test method. In this section, the wood frame was sheathed with four different types of structural foam sheathing on one side and gypsum wallboard (GWB) on the opposite side of the wall frame, with Simpson HDQ8 hold down anchors at the terminal studs. Section two included nine tests studying wall constructed with oriented strand board (OSB) only on one side of the wall frame subjected to gradually applied monotonic loads. Three of the OSB walls were tied to the baseplate with Simpson LSTA 9 tie on each stud. From the test results for Section one; the monotonic tests showed an 11 to 27 percent reduction in capacity from the published design values and for Section two; doubling baseplates, reducing anchor bolt spacing, using bearing plate washers and LSTA 9 ties effectively improved the OSB wall capacity. In comparison of sections one and two, it is expected the walls with structural foam sheathing without hold downs and GWB have a lower wall capacity as hold down and GWB improved the capacity.

• Earthquakes and Structures
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• 제7권2호
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• pp.217-231
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• 2014

Ancient masonry towers are regarded as among the most important historical heritage structures of the world. These slender structures typically have orthogonal and circular geometry in plane. These structural forms are commonly installed with adjacent structures. Because of their geometrical shapes and structural constraints, ancient masonry towers are more vulnerable to earthquake damage. The main goal of the paper is to investigate the seismic behavior of Erzurum Clock Tower under earthquake loading and to determine the contribution of the castle walls to the seismic performance of the tower. In this study, four three-dimensional finite element models of the Erzurum Clock Tower were developed and the seismic responses of the models were investigated. Time history analyses were performed using the earthquakes that took place in Turkey in 1983 near Erzurum and in 1992 near Erzincan. In the first model, the clock tower was modeled without the adjacent walls; in the second model, the clock tower was modeled with a castle wall on the south side; in the third model, the clock tower was modeled with a castle wall on the north side; and in the last model, the clock tower was modeled with two castle walls on both the north and south sides. Results of the analyses show that the adjacent walls do not allow lateral movements and the horizontal displacements decreases. It is concluded that the adjacent structures should be taken into consideration when modeling seismic performance in order to get accurate and realistic results.

• 한국기계가공학회지
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• 제18권10호
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• pp.20-26
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• 2019

This study was conducted on cooling systems in which, for the first time at home and abroad, cold water panels are embedded in the walls of small buildings for radiant cooling by heat absorption with cold water. In summer, cold water is circulated through cold water (chiller) circulation tubes embedded in three walls (two side walls and one rear wall) of a building to implement radiant cooling by the coldness of the water. From the results of this study, the experimental and theoretical natural convection heat transfer coefficients were relatively well-matched over the entire experimental range, thereby verifying the reliability of the experimental results. The surface temperature reduction rate of the walls in which cold water panels are embedded was large whereas that of the walls where no cold water panels are embedded was very small.

• Steel and Composite Structures
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• 제32권3호
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• pp.337-346
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• 2019

The present paper tries to contribute fill the gap of application of the component method to tubular connections. For this purpose, one typical joint configuration in which just one component can be considered as active has been studied. These joints were selected as symmetrically loaded welded connections in which the beam width was the same as the column width. This focused the study on the component 'side walls of rectangular hollow sections (RHS) in tension/compression'. It should be one of the main components to be considered in welded unstiffened joints between I beams and RHS columns. Many experimental tests on double-sided I-beam-to-RHS-column joint with a width ratio 1 have been carried out by the authors and a finite element (FE) model was validated with their results. Then, some different analytical approaches for the component stiffness and strength have been assessed. Finally, the stiffness proposals have been compared with some FE simulations on I-beam-to-RHS-column joints. This work finally proposes the most adequate equations that were found for the stiffness and strength characterization of the component 'side walls of RHS in tension/compression' to be applied in a further unified global proposal for the application of the component method to RHS.