FDM에서 경사면의 표면과 면적오차법의 관계에 대한 연구

전재억,정진서,황영모,김수광,김준안,계중읍,하만경 한국공작기계학회 2002 한국공작기계학회 추계학술대회논문집 Vol.2002 No.-

In any rapid prototyping process, the layer by layer building process introduces an area error between the staircase and the surface line specified by the computer-aided design model. This affects the dimensional accuracy as well as the surface finish for different part build orientations. This paper describes a methodology for computing the area error for any orientation of the part built by the fused deposition modelling system. This technique can be applied to determine the best build orientation of the part, based on the minimum area error. This technique is verified by comparing the results with the experimental measurements of the area error of the parts built at different orientations.

K3에 축적된 내부 응력이 피로 파절에 미치는 영향

김준영,김진우,조경모,박세희 大韓齒科保存學會 2012 Restorative Dentistry & Endodontics Vol.37 No.2

Objectives: This study aimed to evaluate the relationship between the cyclic fatigue of a K3 file and internal stress intentionally induced until the activation of the auto-stop function of the torque-controlled motor. Materials and Methods: K3 (Sybron Endo) .04 and .06 taper, size 25, 30, 35, 40 and 45 were used in this study. To give the internal stress, the K3 files were put into the .02 taper Endo-Training-Bloc (Dentsply Maillefer until the activation of the auto-stop function of the torque-controlled motor. The rotation speed was 300 rpm and torque value was 1.0 N·cm. K3 were grouped by the number of induced internal stress and randomly distributed to 4 experimental groups (n = 10, Stress 0 [control], Stress 1, Stress 2 and Stress 3). For measuring the cyclic fatigue failure, the K3 files were worked against a sloped glass block and time for file separation was recorded. Data was statistically analyzed Statistical analyses were performed using two-way ANOVA and Duncan post-hoc test at p < 0.05 level. Results: Except .04 taper size 30 in Stress 1 group, there were statistically significant differences in time for file separation between control and all experimental groups. K3 with .04 taper showed higher cyclic fatigue resistance than those of .06 taper. Conclusion: In the limitation of this study, the cyclic fatigue of the K3 file was influenced by the accumulated internal stress from use until the auto-stop function was activated by the torque-controlled motor. Therefore, clinicians should avoid the reuse of the K3 file that has undergone auto-stops. (Restor Dent Endod 2012;37(2):74-78)

폐 섬유 보강 복합재의 제조와 마찰특성

차준용,이정민,모상영,이재달,배기서,홍영기 忠南大學校 産業技術硏究所 1996 산업기술연구논문집 Vol.11 No.2

Fiber-reinforced composite materials are used in a wide variety of applications in the advanced field of industries such as electric clutch, motor, car, space and aviation etc. It is well known that the brake lining made of fiber-reinforced composites show excellent friction and wear properties compared to the conventional asbestos brakes and also are known to have high absorption energy and excellent high temperature properties in braking. In order to endow high friction and wear stability to the commercial brake lining, the waste fiber such as cotton, PAN, PET, nylon,kevlar, glass and it's binary mixture fibers were used the fiber reinforcements. The fiber/phenolic resin system has been carried out by preform molding method. The friction tester was especially designed and prepared for evaluation of frictional properties such as friction coefficient and stability. The physical properties of fiber reinforced composites were investigated in terms of the 3-point bending strength, the properties of friction, and morphology. The results obtained from the work are as follows ; 1. The friction properties of the cotton fiber reinforced composites were similar to those of the commercial brake linings, but in the cases of reinforcement of kevlar, glass. we can improve those properties, 2. The proper amount of organic and inorganic fiber mixtures can improve the properties of friction and the mechanical properties, 3. It is more desirable to manufacture hybrid fiber reinforced composites because single cotton or synthetic fiber reinforced composites aren't improved frictional properties, and 4. On evaluating frictional properties of waste fiber reinforced composites, frictional properties of waste fiber reinforced composites are superior to commercial disc lining. Therefore we can confirm practical possibility of waste fiber reinforced disc lining.

농업인 평생학습체계 구축을 위한 농업인교육 발전방안 연구

정철영,송병국,김진모,문택석,허영준,주대진,최수정,한승완 한국농업교육학회 2008 농업교육과 인적자원개발 Vol.40 No.2

이 연구의 목적은 우리나라 농업인의 평생학습체계 구축을 위한 농촌진흥기관의 역할을 정립하고, 한국농업대학의 농업인대학 운영 본부화 방안을 수립하는데 있다. 이를 위해 관련 문헌고찰, 농업인 및 농촌진흥기관의 농업인 교육 담당자들의 인식 및 요구분석, 전문가 자문 및 협의회 등의 방법을 활용하였으며, 이를 토대로 도출된 연구의 결과를 제시하면 다음과 같다. 첫째, 농촌진흥기관의 농업인교육관련 연계를 위해서는 한국농업대학이 농업인평생교육기관으로 평가인정을 받고, 전국의 농업인대학을 총체적으로 지원하는 역할을 수행하는 것이 바람직하다. 이때 지역의 농업기술센터는 한국농업대학과 협력적 관계를 구축하여 학점은행제 운영에 소요되는 교육 및 이력관리를 지원하는 역할을 수행하는 것이 필요하다. 둘째, 한국농업대학의 농업인대학 운영본부화를 위하여 평생학습원의 조직이 추가되는 것이 바람직하다. 이에 따라 평생학습원의 비전, 미션 및 전략이 제시되었으며, 조직의 기능 및 세부과제가 제시되었다. 셋째, 농업인교육의 학점은행제를 도입을 위한 체계를 설정한 후, 농업관련 기존 표준교육과정 분석, 농업인 요구분석, 전국 농업인대학 교육과정 분석, 기존 농업관련 전공 교육과정 분석, 전문가 검토 등의 과정을 거쳐서 '영농 전문학사'와 '농업 경영 학사'의 표준교육과정을 개발하였다. 넷째, 고졸미만 농업인을 위한 사전학습제도화를 위하여 농업인교육의 평가인정을 통한 방안과 One-Stop 평생학습모델을 통한 방안을 제시하였다. The purposes of this research were to assign the role of rural development organizations, and to establish the strategy for the making headquarter of farmer's university. The study was performed as follows: (1) analyzing the related literatures, documents, records review, (2) need analysis of farmers and members ig rural development organizations in terms of farmer's lifelong learning, (3) consulting experts. The following four findings are the results of this study: (1) Korean national agricultural college should be headquarter of farmer's universities and be approve for lifelong learning credit. Also, agricultural technology & extension centers should run educational program for the lifelong learning credit. (2) For the doing role of headquarter of farmer's university, division of lifelong learning should be add to department of technology training in Korea agricultural college. In relation with this, vision, mission and strategy of division of lifelong learning were suggested. (3) Steps for introduction of credit bank system of farmer education were suggested. Also standard curriculums of 'farming associate degree' and 'agricultural management bachelor's degree' were developed through analyzing existing standard curriculum related with agriculture, analyzing need of farmer, analyzing curriculum of farmer's university, analyzing curriculum of agriculture major. (4) For farmer who do not have high school graduate, two solutions were suggested which are approving farmer's education and one-stop lifelong learning model.

흉요추부 굴곡-신연 손상에서 척추체의 골절 양상

고영도,김종오,윤여헌,유재두,정준모 대한골절학회 2003 대한골절학회지 Vol.16 No.2

목적 : 흉요추부 굴곡-신연 손상에 동반되는 척추체의 골절 양상을 알아 보고자 하였다. 대상 및 방법 : 흉요추부 굴곡 - 신연 손상 21례의 방사선 검사를 검토하여 골절된 척추체의 위치, 전후방 추체 높이, 손상된 분절의 후만각, 척추체 골편의 척추관내 침범 정도 및 척추체의 분쇄 정도를 관찰하였다. 결과 : 총 21례 중 압박 골절이 11례, 방출성 골절이 9례 있었다. 척추체 골절은 85%에서 굴곡-신연 손상된 분절내에서 하부 척추체에 위치하였다. 전방 추체 높이는 평균 27% 감소하였고, 압박 골절이 동반된 경우 18%, 방출성 골절이 동반된 경우 40% 감소하였다. 후방 추체 높이는 평균 1% 감소하였고, 압박 골절이 동반된 경우 1% 증가하였으며, 방출성 골절이 동반된 경우 4% 감소하였다. 손상된 분절의 후만각은 평균 19.5도이었고, 압박 골절이 동반된 경우는 15.4도, 방출성 골절이 동반된 경우는 26.8도이었다. 방출성 골절이 동반된 9례 중 골편의 척추관내 침범은 평균 27%이었으며, 척추체의 분쇄 정도는 71.4%에서 경미하였다, 결론 : 흉요추부 굴곡-신연 손상에서 척추세의 골절은 매우 흔하며 분절내 하부 척추체에 호발하였다. 가해진 힘에 비하여 전후방 추체 높이의 감소, 척추관내 침범 및 분쇄 정도가 적었으며, 이는 굴곡력이나 축성 부하의 효과가 신연력에 의해 일부 상쇄되었기 때문이다. Purpose : To evaluate the configuration of vertebral body fractures in flexion-distraction injuries of thoracolumbar spine. Materials and Method : We investigated the location of fractures, anterior or posterior vertebral body height, kyphotic angle of injured segments, canal encreachment and severity of comminution on radiologic examinations of 21 cases. Result : There were 11 compression fractures and 9 burst fractures. 85% of fractures were located in the inferior vertebrae of injured segments. Anterior vertebral height decreased by 27% on average with decrease of 18% in compression fractures and 40% in burst fractures. Posterior height decreased by 1% on average with increase of 1% in compression fractures and decrease of 4% in burst fractures. The average kyphotic angle of injured segments was 19.5˚ with 15.4˚ in compression fractures and 26.8˚ in burst fractures. The canal encreachment in 9 burst fractures was 27% on average, and the comminution of vertebral body was mild in 74%. Conclusion : The fracture of vertebral body in flexion-distraction injuries of thoracolumbar spine was very common, and located on the inferior vertebare of injured segment. The decrease of vertebral height, canal encreachment and severity of comminution was relatively less than the estimated from mechanism of injury, with offset effect of distraction force.

퇴행성 요추부 질환에서 골이식 방법에 따른 치료 결과 : 후외방 유합술 및 후방 요추체간 유합술의 비교 Comparison between Posterolateral Fusion and Posterior Lumbar Interbody Fusion

양준영,이준규,김영모,남대철,강찬 대한정형외과학회 골.연부조직이식학회 2003 대한골.연부 조직이식학회지 Vol.3 No.1

폐암과 동반되어 나타난 기관기관지병증 골연골형성증 1예

이영진,전현수,박시형,김모세,김현주,이승헌,이영민,이현욱,이현경 仁濟大學校 白病院 2010 仁濟醫學 Vol.31 No.-

Tracheobronchopathia osteochondroplastica (TPO) is a rare benign disease of unknown etiology characterized by multiple cartilaginous or bony submucosal nodules, which project into the tracheobronchial lumen. Although some disorders were reported combined with TPO, these seemed to be considered casual. We report a case of TPO that combined with adenocarcinoma of lung. She was 50-year-old non smoking woman presented with chronic cough with right chest pain. Lung mass on right lower lobe was found on chest x-ray, so lung cancer was suspected. Multiple scattered whitish small elevations from trachea to bronchial trees were found on bronchoscopic exam. We mistook these lesions for metastases from lung cancer and biopsies of these lesions were done. Transbronchial biopsy for right lower lobe mass lesion was also done. But biopsies from trachea and bronchus revealed TPO rather than lung cancer. Transbronchial lung biopsy of right lower lobe mass was diagnosed adenocarcinoma of lung. So TPO combined with adenocarcinoma of lung was diagnosed.

근위 대퇴골 및 요추부 골밀도 검사의 상관관계 분석

양준연,김영모 대한골절학회 2003 대한골절학회지 Vol.16 No.4

고출력 레이저에 의한 이종금속 용접시험평가에 관한 연구

유영태,신호준,송성욱,모양우 朝鮮大學校 機械技術硏究所 2004 機械技術硏究 Vol.7 No.1

Laser welding techniques have been characterised for various materials. In this paper. the laser weldability of STS304 stainless steel and Inconel 600 at dissimilar metal welds using a continuous wave Nd:YAG laser are experimentally investigated. Inconel 600 is being used in a steam generator tubing of pressurized water reactor(PWR) exposed to some corrosion. Stress corrosion cracking can occur on this material. An experimental study was conducted to determine effects of welding parameters, on eliminating or reducing the extent welding zone formation at dissimilar metal welds and to optimize those parameters that have the most influence parameters such as focus length, power, beam speed, shielding gas, and wave length of laser were tested.

고출력레이저에 의한 인코넬600의 맞대기용접 시험 평가

유영태,신호준,모양우 조선대학교 에너지.자원신기술연구소 2004 에너지·자원신기술연구소 논문지 Vol.26 No.1

Welding characteristics of Inconel 600 Alloy using a continuous wave Nd:YAG laser are experimentally investigated. The major process parameters studied in the present laser welding experiment were position of focus, laser power, travel speed. The gap and offset maintained as small as possible. Optical microscope were used to investigate the microstructures of the welded zone. This study shows the result of the tension experiments. And then this paper used the Electronic Speckle Pattern Interferometry to present the welding residual stress in welds. The follow conclusions can be drawn the laser power and travel speed have a pronounced effect the fusion zone size and shape.