• Journal of Welding and Joining
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• 제25권5호
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• pp.64-71
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• 2007

The aim of this paper is to investigate the effects of welding parameters on the weld shape in seal-welding of STS304L capsule for manufacturing a radioisotope source which is widely used in nondestructive testing of metal structures using gamma ray. Pulsed gas tungsten arc (Pulsed GTA) welding is performed for thin cross sectional area of the capsule. Seven welding parameters including current waveform parameters and arc length etc. are selected as main process parameters using design of experiment. The weld shape such as bead width, penetration depth, weld area, aspect ratio and area rate is investigated to assess the effects of welding parameters. As results, the combination of pulse duty/welding speed largely affects on bead width, penetration depth, area and aspect ratio. Finally, it is concluded that the key parameters are the combination of pulse duty/welding speed, base current and arc length, and their optimal conditions are 50%/1.77mm/s, 6.4A and 1 mm.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제34회 춘계학술대회논문집
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• pp.251-253
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• 2010

산화제 개폐밸브 개발 과정의 시험에서 금속 코니컬 씰이 장착된 밸브 중간 플랜지부에서 외부 누설이 발생하였다. 이에 기밀과 관련된 형상 변수인 볼트 수 및 플랜지 형상이 변경된 3가지 모델에 대하여 구조 해석을 수행하여, 설계 변경에 따른 무게 증가를 줄이고 동시에 플랜지간 벌어짐 양이 가장 적은 모델을 개선 모델로 선정하였다. 선정된 모델의 플랜지 부를 모사하는 시험 치구를 제작하여 기밀시험을 재수행하여 누설이 발생하지 않는 것은 확인하였으며, 결과적으로 플랜지 부의 기밀을 확보할 수 있는 설계 해석 방법을 검증하였다.

• 대한치과보철학회지
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• 제34권4호
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• pp.869-902
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• 1996

Flexion of a metal/ceramic fixed partial denture(EPD) frameworks under function can cause fracture of porcelain or deterioration of the cement seal. This study evaluated the flexion characteristics of three-unit mandibular FPD frameworks, repacing the second pre-molar under compressive load(200g, 400g). Testing was accompished with real-time holographic interferometry, using 6 porcelain fused-to metal frameworks. Tested alloys were non-precious alloy(Heracles, Holland), semi-precious alloy(Degudent U, Germany) and precious alloy(Degudent H, Germany). Changes of the fringe patterns according to the heat treatment(porcelain firing cycle), various loads(200g, 400g), occlusal forms(occlusal porcelain veneering, facial porcelain veneering), various alloys and post-soldering units were compared. Dental study model(Nissan dental products, Inc. D51DP-500A, Japan) and six 3-unit metal/ceramic fixed partial denture frameworks were used as experimental materials. 36 holograms were taken on fixed dental study model by using the 10mW He-Ne laser and real-time holographic interferometry. On the basis of this study, the following conclusions can be drawn : 1. In the frameworks for facial porcelain veneering, the semi-precious alloy framework was least deformed and precious alloy framework, non-precious alloy framework orderly before heat treatment, and the deformation was not shown great difference among three alloys after heat treatment and post-soldering. 2. In the frameworks for occlusal porcelain veneering, the precious alloy framework was greatest deformed and the deformation was not difference between semi-precious alloy framework and non-precious alloy framework before, after heat treatment, and the deformation was not shown great difference among three alloys after post soldering. 3. In the non-precious alloy frameworks for facial porcelain veneering and occlusal porcelain veneering, the deformation was greatly decreased after heat treatment and conversely increased after post-soldering. 4. In the semi-precious alloy framework for facial porcelain veneering, the deformation was not detectable after heat treatment and increased after post-solder. And in the frame-work for occlusal porcelain veneering, the deformation was slightly decreased after heat treatment and increased after post-soldering. 5. In the precious alloy framework for facial porcelain veneering, the deformation was greatly decreased after heat treatment and increased after post-soldering, And in the framework for occlusal porcelain veneering, the deformation was greatly decreased after heat treatment and decreased after post-soldering.

• 헤리티지:역사와 과학
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• 제56권1호
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• pp.46-61
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• 2023

삼척 흥전리사지는 2014년부터 2020년까지 시·발굴조사를 통해 서원인 예불영역과 동원인 생활영역으로 나누어진 다원식 가람이라는 것이 밝혀졌다. 흥전리사지의 시·발굴에서 금동투조장식과 청동정병, 금동사자진병향로의 사자 등 비교적 다양한 불교공예품이 출토되었다. 흥전리사지의 서원 금당지 출토 금동투조장식은 불전 장엄에 사용했던 금동번으로 추정되고 현재까지 발견된 통일신라의 금동투조장식 중 가장 수준 높은 예로 왕경에서 제작한 것으로 보인다. 동원 출토 금동사자진병향로의 사자와 청동정병은 생활영역에서 출토된 공양구로 행향 등의 의례에 사용했을 것으로 보인다. 사자진병향로는 왕경보다는 지방에서 출토된 것들이 제작시기가 앞서고 있어 지방에서 왕경으로 전파된 것으로 보이고, 청동정병은 석굴암 범천의 지물로도 표현되고 있어 8세기 후반 이전 왕경에 군지형 정병이 있었을 것으로 보이나 출토품이 없어 영향관계는 추후에 밝혀야 할 것으로 생각된다. 청동대접과 청동합은 왕경의 월지와 황룡사지, 인왕동사지 출토품과 유사하여 왕경의 청동기명이 지방으로 확산된 것으로 생각된다. 청동인장은 흥전리사지 이외의 지방에서도 출토되었지만, 황룡사지 출토품과 형식과 인장의 서체 등이 동일하여 『삼국사기』 문무왕조의 기록처럼 왕경에서 제작하여 보낸 것으로 보았다. 더불어 인장의 '범웅관아지인(梵雄官衙之印)'은 흥전리사지가 당시 승단조직과 관련된 것을 보여주는 것이라 할 수 있다. 삼척 흥전리사지 출토 불교공예품은 '국통(國統)'명 비편 등의 내용으로 보아 비의 주인공이었던 선종 승려가 선종 사찰에서 9세기 전반에서 중반 경에 사용했던 것으로 보인다. 또한 금동투조장식과 금동사자진병향로의 사자, '범웅관아지인'의 청동인장 등의 제작수준으로 보아 흥전리사지의 사격은 상당히 높았던 것으로 보이며, 9세기 전반에서 중반경 통일신라의 왕경과 지방의 공예품이 일방적인 영향이 아니라 양방향의 영향이 있었다는 것을 보여주는 중요한 예라고 할 수 있다.

• 센서학회지
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• 제26권1호
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• pp.39-43
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• 2017

Development of vision system as a nondestructive evaluation system can be very useful in screening the defective mechanical parts before they are assembled into the final product. Since the tens of thousands of the mechanical parts are used in an automobile carefully inspecting the quality of the mechanical parts is very important to maximize the performance of the automobile. To sort out the defective mechanical parts before they are assembled, auto parts fabrication companies employ various inspection systems. Nondestructive evaluation systems are getting rapidly popular among various inspection systems. In this study, we have developed a vision system to inspect the inside of the brake caliper, a part that is used to compose a brake which is the most important to the safety of the drivers and the passengers. In a brake caliper, a piston is pushed against the brake disk by oil pressure, causing a friction to damp the rotation of the wheel. Inside the caliper, a groove is positioned to adopt an oil seal to prevent the oil leaks. Inspecting the groove with our vision system, we could examine the existence of the contaminants which are normally the residual tiny pieces from the machining process. We used a high resolution GigE camera, 360 degree lens to look in the inside view of the caliper at once, and a special illumination system in this vision system. We used the edge detection technique to successfully detect the contaminants which were in the form of small metal chips. Labview graphical program was used to process the digital data from the camera and to display the vision and the statistics of the contaminants. We were very successful in detecting the contaminants from the various size calipers. We think we are ready to employ this vision system to the caliper production factories.

• 대한치과보철학회지
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• 제33권2호
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• pp.358-394
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• 1995

The author studied the actual conditions on the production of dental prosthesis made in laboratories, and also studied interrelationships between dentists and laboratory technicians in both personal and technical aspects. Two hundred-eighty four technicians, work in dental laboratories presently, were surveyed via mail and direct contact during the period from June 1 to June 30 and August 27 to August 28 in 1994 respectively. The obtained results were as follows : 1. Among the respondents, 90.5% we re working in commercial dental laboratories and their laboratories were mainly located in the Seoul area(40.9%, P<0.05). The numbers of employees in these laboratories were less than 10 persons(70.0%, P<0.01), and 75.9% of these laboratories have been in operation less than 15 years. 2. Most laboratory procedures were accomplished according to established disciplines. However, procedures such as die trimming in fixed restorations and the qualifications of the people designing removable partial dentures were not. Other problem areas were boxing of the working cast, the person determining the posterior palatal seal area, selection and arrangement of artificial teeth, occlusion rim correction and laboratory remounting of the processed denture in complete denture restorations. 3. Only half of the requesting dentists could send work authorizations to the laboratories with their work and even so, its contents were quite lacking. Consequently, there must be some standards in writing work authorization. 4. Technicians most desired clean and accurate impressions in fixed and removable dentures, and enough tooth reduction in porcelain fused to metal restorations. 5. For the establishment of better relationships between dentist and dental technician, the respondents desired the establishment of equal footing first(33.5%), and frequent conversations and muture understanding second(25.9%).

• 센서학회지
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• 제15권1호
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• pp.58-64
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• 2006

In this study, we describe a low-temperature wafer-level thermocompression bonding using electroplated gold seal line and bonding pads by electroplating method for RF-MEMS devices. Silicon wafers, electroplated with gold (Au), were completely bonded at $320^{\circ}C$ for 30 min at a pressure of 2.5 MPa. The through-hole interconnection between the packaged devices and external terminal did not need metal filling process and was made by gold films deposited on the sidewall of the throughhole. This process was low-cost and short in duration. Helium leak rate, which is measured to evaluate the reliability of bonded wafers, was $2.7{\pm}0.614{\times}10^{-10}Pam^{3}/s$. The insertion loss of the CPW packaged was $-0.069{\sim}-0.085\;dB$. The difference of the insertion loss between the unpackaged and packaged CPW was less than -0.03. These values show very good RF characteristics of the packaging. Therefore, gold thermocompression bonding can be applied to high quality hermetic wafer level packaging of RF-MEMS devices.