• The Korean Journal of Nuclear Medicine
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• v.29 no.1
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• pp.118-124
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• 1995

단일광자방출전산화 단층촬영술을 이용한 영상정보를 효과적으로 얻기 위하여 고려되어야 할 사항으로는 1) 조준기(collimator)의 선택, 2) 기질(matrix)의 크기, 3) 회전각의 수 (number of angles), 4) 360도 또는 180도 획득(acquisition), 5) continuous 또는 step& shoot, 6) 원형 또는 비원형회전 등이 있다. 저자들은 비원형회전으로 검체와 검출기 사이의 거리를 단축시킴으로써 직선성, 균일성, 대조도, 해상력에 미치는 영향을 알아보기 위하여 원형회전 방법과 비교하여 다음과 같은 결과를 얻었다. (1) 비원형회전을 하여도 균일성(uniformity)과 직선성(linearlity)을 유지한다. (2) 균일성, 대조도(contrast), 해상력(resolution)들이 비원형 회전을 한 경우에 보다 더 개선되었다. (3) 영상 획득시간은 비원형회전인 경우에 더 소요되었다. (매스캔 당 10분) 따라서 검사자는 영상 화질의 개선효과와 상반되는 보정(calibration)과 설치(set-up)에 소요되는 시간(매스캔당 10분이상)을 비교하여 자료획득(data acquisition) 회전방법을 선택하여야한다.

• Korean Journal of Microbiology
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• v.23 no.4
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• pp.265-270
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• 1985

Overall procedure of cell fusion between Brevibacterium flavum and Corynebacterium glutamicum was morphologically observed by transmission electron microscopy. Protoplasts formed by treatment of cells with penicillin G and lysozyme in order were released through the pores generated on a certain region of cell walls to be spherical form. When two different protoplasts were met, cell wall and membrane in the contact zone was disappeared and followed by the mutual exchange of cytoplasmic and/or chromosomal materials. Cell xall regeneration speed of the protoplasts fused was slower than that of the non-fused, whereas the size of the former was confirmed as bigger than that of the latter.

• Journal of the Korean Society for Advanced Composite Structures
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• v.1 no.2
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• pp.36-43
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• 2010

In this study, the buckling loads and mode shapes characteristic of circular and non-circular(elliptical) closed composite shells were analyzed. To analyses the buckling behaviors, we develop and report an improved generalized shell element called 4EAS-FS through a combination of enhanced assumed strain and the substitute shear strain fields. A flat shell element has been developed by combining membrane element with drilling degree-of-freedom and a plate bending element. The combined influences of length, thicknesses, cross-sectional parameters, and fiber-angle on the critical buckling loads and mode shapes of circular and non-circular(elliptical) closed shells are examined.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.6
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• pp.1292-1300
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• 1989

본 연구에서는 비원형관의 평판길이의 변화가 평판과 원관사이의 상호작용 으로 나타나는 온도장, 유동장, 국소 Nusselt 수 및 평균 Nusselt 수에 미치는 영향 에 대하여 고찰하였다.

• Proceeding of EDISON Challenge
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• 2012.04a
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• pp.61-64
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• 2012

원형 실린더 주위의 비정상 유동은 공학적으로 매우 중요한 유동 현상으로서 2차원 원형 실린더 주위의 비정상 유동 현상인 와류 흘림에 관해 수치적으로 계산해 보고 실제 유동 현상과 비교해 본다. 또한 실린더 주위 유동의 와류 흘림 현상이 공학적인 측면에서 어떠한 중요한 역할을 하는지 고찰해 본다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.7
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• pp.743-749
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• 2014

In this study, a noncircular drawing (NCD) sequence for manufacturing high-strength and high-ductility pearlitic steel wires was investigated. Multipass NCD was conducted up to the 12th pass at room temperature with two processing routes (defined as the NCDA and NCDB), and compared with the wire drawing (WD). During the torsion test, delamination fracture in the drawn wire was observed in the 10th pass of the WD whereas it was not observed until the 12th pass of the NCDB. From X-ray diffraction, the circular texture component that increases the likelihood of delamination fracture of the drawn wire was rarely observed in the NCDB. Thus, the improved ability of the multipass NCDB to manufacture high-strength pearlitic steel wires with high torsional ductility compared to the WD (by reducing the likelihood of delamination fracture) was demonstrated.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.682-685
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• 2017

An experimental study was carried out to investigate the injection characteristics of non-circular effervescent type twin-fluid nozzles. For this purpose, two types of non-circular nozzles (E1, E2) and one kind of circular nozzle (C) were used. At this time, the Aerorator mounted on the nozzle used three different diameters to match the aspect ratio with the nozzle exit area. Therefore, experiments were performed according to three aspect ratios for each nozzle, and a total experiments were conducted. Experiments were carried out by controlling the amount of air flowing after fixing the flow rate of the liquid, and the nozzle internal pressure and SMD were measured, and the jet image was taken from the nozzle. The discharge coefficients of the three kinds of nozzles were compared with the conventional equation and the Jedelsky's equation, and the Jedelsky's equation was found to be about 4 times larger. The droplet size (SMD) injected from the nozzle was found to be smaller in the non-circular shape than in the circular shape, which is expected to be caused by the difference of the discharge coefficient values.

• Journal of Korean Society of Steel Construction
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• v.21 no.5
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• pp.505-514
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• 2009

This paper describes the structural behavior and the ultimate strengths of circular hollow steel (CHS) sections based on a series of compression tests. The ultimate strengths of CHS section columns are mainly dependent on both diameter-thickness ratio and column slenderness ratio. For the CHS sections with a high diameter-thickness ratio, an elastic or an inelastic local buckling may occur prior to the overall buckling, and it may decrease the column strength. Test sections were fabricated from SM400 steel plate of 2.8 mm and 3.2 mm in thickness and were tested to failure. The diameter-thickness ratios of the test sections ranged from 45 to 170 to investigate the effect of local buckling on the column strength. The compression tests indicated that the CHS sections of lower diameter-thickness ratio than the yield limit in the current design specifications showed an inelastic local buckling and a significant post-buckling strength in the local mode. Their ultimate stresses were larger than the nominal yield stress. It was known that the allowable stresses of the sections predicted by the Korean Highway Bridge Design Specifications (2005) were too conservative in comparison with test results. The Direct Strength Method which was newly developed was calibrated for application to the CHS sections by the experimental and numerical results. The Direct Strength Method proposed can predict properly the ultimate strength of CHS section columns whether a local buckling and an overall buckling occur nearly simultaneously or not.

• Journal of the Korean Society of Costume
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• v.51 no.8
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• pp.111-121
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• 2001

본 연구는 중년여성의 상반신을 대상으로 기존원형에 대한 평가를 실시한 후 이를 기본으로 제도법을 수정·보완하여 중년여성 체형에 맞는 상반신 토루소 연구원형을 제작하기 위한 목적으로 연구되었다. 연구 대상은 35세에서 59세의 중년여성으로 하였으며, 45세를 전후로 체형이 변한다는 선행 연구를 토대로 중년 전기(35세∼45세), 중년 후기(46세∼59세)로 나눠 연구하였다. 연구원형 제작을 위해서 97년 국민체위조사보고 자료에 나온 35세∼59세에 해당하는 신체치수를 사용하여 대학에서 교재로 사용되고 있는 4가지 원형을 설계하고 이를 CADsystem을 이용하여 각 Pattern간의 차이를 정확하게 비교하고, 4가지 원형의 실험복을 제작하여 착의 실험을 통해 객관적 평가 11항목, 주관적 평가 23항목에 대해 설문 조사를 하여 문제점을 파악하였다. 이를 기초로 연구원형을 제작하였고 제작 후 연구원형의 신체 적합성을 알아보기 위해 기존원형과 마찬가지로 착의 실험을 하여 평가하였다. 실험 결과 기존원형들이 착용시 진동부분과 뒤중심부분의 당김으로 인해 착용자가 불편함을 느끼는 것으로 나타났고 외관상으로는 가슴둘레와 엉덩이둘레 부분에 여유분량이 중년여성 체형에 비해 상대적으로 적었으며 가슴선, 허리선, 엉덩이선의 위치 역시 중년여성의 체형과는 맞지 않은 것으로 나타났다. 대체로 중년 전기에 비해 중년 후기에서 수정 보완이 더 요구되었는데 특히 나이가 들수록 등이 뒤로 젖혀지는 현상으로 인해 측면에서 봤을 때 허리가 들어가는 현상이 두드러져 뒤 허리부분의 수정이 요구되었다. 이에 연구원형에서는 기존원형에서 나타났던 가슴선, 허리선, 엉덩이선의 위치 조절을 위해 앞목기준선을 위로 2cm 올려 주었고 가슴둘레와 엉덩이둘레 부분에 여유분을 각각 2cm더 주어 제작하였으며 중년 후기에서 두드러지게 나타났던 뒤허리부분의 문제점을 허리중심선 설정시 1∼2cm안쪽으로 설정하여 체형변화를 반영하였다. 이에 따른 연구원형에 대한 주관적·객관적 착의 평가 결과는 착용시 기존원형에서 나타났던 진동부분과 뒤중심부분의 당김이 없어지고 외관상 가슴선, 허리선, 엉덩이선이 기존원형보다 개선된 것으로 나타났으며, 전체적인 외관에서도 전·후기 모두 기존원형 보다 좋은 것으로 평가되었다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.3
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• pp.370-377
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• 2001

This paper proposed an eccentric annular ring microstrip antenna which has an asymmetric slot and a tuning stub for improving bandwidth and size of the circular microstrip patch antenna. The field characteristics of the eccentric annular ring microstrip antenna have been calculated by using the method of FDTD (finite difference time domain). The calculated results showed good agreement with the measured results. As a result of measurement, the antenna size and the bandwidth has been improved to that of 12.2 % and 4.8 % respectively, comparing to circular microstrip patch antenna.