• 한국방사선학회논문지
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• 제14권7호
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• pp.1003-1011
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• 2020

본 연구는 듀얼 에너지 CT를 사용하여 금속인공물을 감소시키는 기법을 적용함에 있어 단일 선원과 이중 선원간의 영상 차이를 비교 평가하고자 한다. 단일 선원 장치로는 Discovery CT 256(GE, USA), 이중 선원 장치로는 Somatom Definition Flash(Siemens Health Care, Forchheim, Germany)를 이용하였다. 자체 제작한 팬텀(의료용 Titanium Screw를 삽입한 돼지다리)을 이중에너지 CT를 이용하여 동일 조건하에 선량을 변화시키며 영상을 얻은 후 정량적, 정성적 평가 하였다. 평가 방법으로는 뼈 주변, 조직 주변으로 나누고 금속삽입물로 인해 발생한 금속인공물(선속경화, 산란, 줄무늬)에 대하여 SNR을 측정하여 비교 분석하였다. 단일 선원 장치와 이중 선원 장치 간 금속 인공물 감소기법에는 영상의 차이가 있었다. 단일 선원 장치에서는 금속삽입물에 의한 선속경화 인공물이 이중 선원 장치에서 얻은 영상보다 많은 감소를 보이며 인공물의 방해 없이 주변 조직부가 잘 관찰 되었다. 이중 선원 장치에서는 금속삽입물에 의한 산란과 줄무늬 인공물이 단일 선원 장치에서 보다 많은 감소를 보이며 금속삽입물을 둘러싼 인접 조직들의 신호가 감소 없이 잘 관찰 되었다. 환자를 검사 시 보고자 하는 부위가 금속삽입물에 인접한 주변 조직이냐, 금속삽입물을 감싸는 전체적 조직이냐에 따라 단일 선원 장치와 이중 선원 장치를 구분하여 검사가 행해진다면 진단적으로 도움이 되는 영상을 획득할 수 있을 것으로 생각된다.

• Journal of Welding and Joining
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• 제14권1호
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• pp.99-106
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• 1996

Development of an automatic TIG welding system incorporating a vision sensor and torch control mechanism leads to an improved welding quality and greater production efficiency. The automatic welding system should be greatly restricted in its size and weight for the LNG(Liquefied Natural Gas) storage tank and also provide a unique torch rotating mechanism which keeps the torch tip in the constant position while the angle is changed continuously to maintain the welding torch substantially perpendicular to the weld line. The developed system is driven by two translation axes X, Z and one rotational axis. A moving line window method is adopted to the image recognition of the corrugated membranes with specular reflection. This method decides original laser stripe patterns in image which is affected by multi-reflection. A self-teaching algorithm, which guides the automatic welding machine with the information provided by the CCD camera without any previous learning of a reference trajectory, was developed for tracking the corrugated membrane of the LNG tank along the weld line.

• Journal of Korean Vacuum Science & Technology
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• 제3권1호
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• pp.79-84
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• 1999

the photolithographic patterning on an indium-tin oxide (ITO) glass and the electro-phoretic deposition were combined for preparing the screen of the full-color field emission display(FED). the patterns with a pixel of 400$\mu\textrm{m}$ on the ITO-glass were made by etching the ITO with well-prepared etchant consisting of HCL, H2O, and HNO3. Electrophoretic method was carried out in order to deposit each spherical red (R), green(G), and blue (B) phosphor on the patterned ITO-glass. The process parameters such as bias voltage, salt concentration, and deposition time were optimized to achieve clear boundaries. It was found that the etching process of ITO combined with electrophoretic method was cost-effective, provided distinct pattern, and even reduced process steps compared with conventional processes. The application of reverse bias to the dormant electrodes while depositing the phosphors on the stripe pattern was found to be very critical for preventing the cross-contamination of each phosphor in a pixel.

• 제어로봇시스템학회논문지
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• 제22권10호
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• pp.811-816
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• 2016

In light of recently developed 3D printers for rapid prototyping, there is increasing attention on the 3D scanner as a 3D data acquisition system for an existing object. This paper presents a prototypical 3D scanner based on a striped laser light image. In order to solve the problem of shadowy areas, the proposed 3D scanner has two cameras with one laser light source. By using a horizontal rotation table and a rotational arm rotating about the latitudinal axis, the scanner is able to scan in all directions. To remove an additional optical filter for laser light pixel extraction of an image, we have adopted a differential image method with laser light modulation. Experimental results show that the scanner's 3D data acquisition performance exhibited less than 0.2 mm of measurement error. Therefore, this scanner has proven that it is possible to reconstruct an object's 3D surface from point cloud data using a 3D scanner, enabling reproduction of the object using a commercially available 3D printer.

• 한국해양공학회지
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• 제16권2호
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• pp.53-59
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• 2002

This paper shows the experimental results controlling the height of surface and back bead in GMAW by analyzing the unexpected gaps between base metals produced in welding and by controlling welding velocity due to the variation of the gap between base metals in thin-plate welding. The back bead behavior and burn-through in I-type butt joint $CO_2$ welding of thin mild steel are analyzed in the views of short circuit time ratio and short circuit frequency. It is shown through experimental consideration that the short circuit time ratio method is more reasonable than the short circuit frequency method in analyzing the formulation of back bead under changing the gap between base metals. Based on the these results, welding manipulator is designed so as to satisfy the bead height control in real time by measuring the short circuit time ratio. To show the effectiveness of the developed bead formulation control system, the experiment is implemented under two welding conditions such as increasing gap from 0mm to 0.8mm and gradually increasing gap from 0mm to 1.2mm. The experimental results show that the bead formulation can be controlled uniformly in spite of the variation of the gap between base metals.

• 한국정보과학회논문지:시스템및이론
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• 제30권7_8호
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• pp.397-407
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• 2003

인간의 신체에 대한 정확한 3차원 표면모델을 추출할 수 있는 기술에 대한 요구와 관심이 최근 멀티미디어 등 다양한 응용 분야에서 증폭되고 있다. 본 논문에서는 인체의 ,3차원 모델을 효율적으로 추출하기 위한, 3차원 스캐너를 소개하였으며, 취득된 3차원 정보로부터 등고선(Wire-frame Contour)을 안정적으로 생성하는 반자동 등고선 생성 방법을 제안하였다. 또한 생성된 등고선으로부터 3차원 표면모델을 추출하기 위한 표면 삼각분할 알고리즘을 제안하였다. 실험을 통해 개발된 시스템과 제안된 방법이 안정적이고 효과적으로 인체의, 3차원 표면모델을 생성하는 것을 확인할 수 있었다.

• 대한수의학회지
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• 제59권3호
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• pp.119-122
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• 2019

The goals of this study were, first, to evaluate the feasibility of inducing gastric perforation with 99% alcohol injection after electrocautery (EA-method), and, second, to observe "enhanced peritoneal stripe sign (EPSS)" and other lesions upon induction of gastric perforation. Six clinically normal beagle dogs were prepared for gastric perforation using endoscopy. After gastric perforation, EPSS and other lesions on ultrasonography were observed eventually (at 0 h, 3 h, day 1, day 2, day 3, day 4, day 5, and day 6). We graded the EPSS depending on its width and number. EPSS was observed until day 4 of the examination in all the 6 dogs. The grades of EPSS were the highest at 3 h and declined gradually. Peritoneal effusion was observed in all dogs at 3 h and on day 1. Regional bright mesenteric fat was confirmed in all dogs on days 3 and 4. In conclusion, gastric perforation can be induced by EA-method. EPSS and peritoneal effusion appear at a very early stage, and regional bright mesenteric fat was identified on days 3 and 4 in almost all dogs with gastric perforation.

• Acta Via Serica
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• 제7권2호
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• pp.39-64
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• 2022

Ancient Iranians highly esteemed the horse and horse tacks, one of which is the jul (saddlecloth). It is a felt, sheepskin, or woven pad placed between the horse's back and saddle. The aim of this paper is to identify and categorize jul designs in the Sāsānian period. The research questions are about the variety of jul designs and how to categorize them. This is fundamental research and the method is descriptive and analytical. Neither a jul nor a saddle-cover remains from the Sāsānian period, therefore the statistical population includes all available items, such as metal and stone items and parget and plasterworks, in which juls are recognizable. Due to the scarcity of such items, all the available samples were studied; so the sampling method is a total enumeration. This is documentary research by means of note-taking and using reliable websites; the data has been analyzed qualitatively. The results show that jul designs were not diverse in the Sāsānian period. All-over designs were dominant. In terms of pattern types, these designs are classified into five groups, each of which has its own formal and aesthetic characteristics: all-over design with a four-petal flower pattern, allover design with a checkered pattern, all-over design with a spotted pattern, allover design with a tiger stripe pattern, and all-over design with a zigzag pattern.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 추계학술발표강연 및 논문개요집
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• pp.20-20
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• 2003

We developed 30 ㎽-AlInGaN based violet laser diodes. The fabrication procedures of the laser diodes are described as follows. Firstly, GaN layers having very low defect density were grown on sapphire substrates by lateral epitaxial overgrowth method. The typical dislocation density was about 1-3$\times$10$^{6}$ /$\textrm{cm}^2$ at the wing region. Secondly, AlInGaN laser structures were grown on LEO-GaN/sapphire substrates by MOCVD. UV activation method, instead of conventional annealing, was conducted to achieve good p-type conduction. Thirdly, ridge stripe laser structures were fabricated. The cavity mirrors were formed by cleaving method. Three pairs of SiO$_2$ and TiO$_2$ layers were deposited on the rear facet for mirror coating. Lastly, laser diode chips were mounted on AlN submount wafers by epi-down bonding method. The lifetime of the laser diodes was over 10,000 hrs at room temperature under automatic power controlled condition. We expect the performance of the LDs to be improved by the optimization of the growth and fabrication process. The detailed characteristics and important issues of the laser diodes will be discussed at the conference.

• 식물병연구
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• 제8권2호
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• pp.92-100
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• 2002

한국산 땅콩에 감염되어 있는 바이러스를 동정하기 위하여 땅콩 재배지 에서 모자이크, 괴저를 동반한 얼룩무늬, 황화, 줄무늬, 엽맥녹대, 위축 등의 바이러스 감염 증상을 나타내는 땅콩잎 및 땅콩을 채집하였다. 이들 시료로부터 기주범위, 면역전자현미경(ISEM), 감염 세포내의 바이러스의 존재양식, direct immune staining assay(DISA), RT-PCR 등에 의하여 Bean common mosaic virus(BCMV-PSt)와 Peanut mottle virus(PeMoV)를 분리하였다. 이들 시료를 DN법에 의거하여 전자현미경으로 관찰한 바 길이가 약 780 nm의 사상형 입자와 세포질 봉입체를 관찰하였다. 초박절편의 시료 관찰에서도 길이 약 700 nm의 사상 입자가 엽육세포 등의 세포질과 액포에 산재 혹은 병행 배열로 존재해 있는 영상 및 세포질 봉입체가 반드시 확인되었다. 또한, 이들 시료를 BCMV-PSt와 PeMoV의 항혈청으로 ISEM을 실시한 결과, 두 항체에 모두 decoration 되었음을 확인하였다. 두 바이러스가 종자전염이 되는 지를 확인하기 위하여 땅콩을 직접 BCMV-PSt와 PeMoV의 항혈청으로 DISA를 실시하였다. 그 결과, BCMV-PSt 및 PeMoV 항혈청에 발색이 되었으며, 이들을 발아시켜 유식물체를 획득하였다. 이들 유식물체에서도 바이러스 감염 증상인 얼룩무늬 증상이 관찰되었고, 이들을 BCMV-PSt와 PeMoV의 항혈청으로 ISEM방법으로 검경한 결과, 두 항체에 모두 decoration 되었다. 또한, 자연감염 식물체 및 DISA에 의해 바이러스 감염이 확인된 종자를 발아시킨 2년생 식물체로부터 생물검정 법 및 ISEM에 의해 두 종의 바이러스가 검출되었다. Rl-PCR을 실시한 결과, 약 1.2Kb크기의 BCMV-PSt coat protein유전자가 증폭 되었다. 이 연구결과, 한국산 땅콩에 BCMV-PSt가 가장 많이 감염되어 있음을 확인하였다.