• International Journal of Korean Welding Society
• /
• 제3권1호
• /
• pp.8-16
• /
• 2003

A major concern in Gas Metal Arc (GMA) welding process is the determination of welding process variables such as wire diameter, gas flow rate, welding speed, arc current and welding voltage and their effects on the desired weld bead dimensions and shape. To successfully accomplish this objective, 81 welded samples from mild steel AS 1204 flats adopting the bead-on-plate technique were employed in the experiment. The experimental results were used to develop a mathematical model to predict the magnitude of bead geometry as follows; weld bead width, weld bead height, weld bead penetration depth, weld penetration shape factor, weld reinforcement shape factor, weld bead total area, weld bead penetration area, weld bead reinforcement area, weld bead dilution, length of weld bead penetration boundary and length of weld bead reinforcement boundary, and to establish the relationships between weld process parameters and bead geomery. Multiple regression analysis was employed for investigating and modeling the GMA process and significance test techniques were applied for the interpretation of the experimental data.

• 치과방사선
• /
• 제17권1호
• /
• pp.107-120
• /
• 1987

The purpose of this study was three-fold: to reexamine whether periapical and central lesions can be detected on the radiograph when they are in the cancellous bone, to investigate regianal differences in radiograph visualization of the lesion, and to. compare the interpretation of radiagraphs by densitometric analysis with the visual interpretation af the same radiographs. Forty-nine apical lesions and eighty-two central lesions were made in 8 mandibles and radiographed serially while being enlarged and deepened. All radiagraphs were evaluated by three dental radiologists. Each lesion was scored of 3 to 0, based on the radiographic appearances. Special radiographs of 15 apical and central lesions were analysed by densitometer and the results were compared with the scores which were previously assigned by three examiners. From this study the following conclusians could be drawn; 1. Experimental lesions confined to cancellous bone were detected an the radiagraphs in 41.3% of the cases. 2. Visualization of periapical lesions in cancellous bone was more apparent than that of central lesions in cancellous bone. 3. Visualization of the periapical lesions confined to. cancellous bane was highest in molar teeth, and detection of the central lesions in alveolar portion was easier than those in lower portion of mandibular body area. 4. It was possible to detect the experimental lesions without cortical plate involvement in 78.6% of the all lesions. 5. Densitometric analysis of radiographs could reproducibly distinguish bone changes, especially of central lesions in cancellous bone.

• 디지털융복합연구
• /
• 제15권2호
• /
• pp.355-360
• /
• 2017

디자인의 기본 요소인 선을 활용하여 금속조형물을 시각적으로 완성하기 위해 시작된 본 연구는 선의 다양한 특징과 개념을 살펴보고 선행된 연구 중에서, 선을 중심으로 진행된 작품연구들을 통해 선의 조형적 아름다움을 알아보았다. 그 결과 선의 조형적 해석은 크게 선의 굵기와 선의 장단에 의한 의도적 표현으로 진행됨을 알 수 있었다. 선행 연구들을 바탕으로 연구자는 기존의 선의 조형적 표현에서 벗어나 시각적으로 자유로우면서도 미적 아름다움을 함께 느낄 수 있는 금속조형물을 얻기 위해 적동판과 인청동선 용접을 활용하여 선의 변형과 반복으로 하나의 패턴을 완성하고 이를 통해 작품으로 연계하였다. 그 결과 선의 면적인 표현은 물론 전체적 형태의 입체감과 속도감, 통일감을 함께 느낄 수 있었다. 앞으로도 선의 조형적 해석은 더 많이 연구되어야 할 것이며, 더 나아가 선의 표현을 통한 감성적, 내재적 아름다움에 대한 다양한 연구가 계속 되어야 할 것이다.

• Steel and Composite Structures
• /
• 제13권6호
• /
• pp.571-586
• /
• 2012

The paper addresses some key issues related to the design of composite slabs with cold-formed profiled steel sheets. An experimental programme is first presented, involving six composite slab specimens tested with a view to evaluating Eurocode 4 (EC4) provisions on testing of composite slabs. In four specimens, the EC4-prescribed 5000 load cycles were applied using different load ranges resulting from alternative interpretations of the reference load $W_t$. Although the rationale of the application of cyclic loading is to induce loss of chemical bond between the concrete plate and the steel sheet, no such loss was noted in the tests for either interpretation of the range of load cycles. Using the recorded response of the specimens the values of factors m and k (related to interface shear transfer in the composite slab) were determined for the specific steel sheet used in the tests, on the basis of three alternative interpretations of the related EC4 provisions. The test results confirmed the need for a more unambiguous description of the m-k test and its interpretation in a future edition of the Code, as well as for an increase in the load amplitude range to be used in the cyclic loading tests, to make sure that the intended loss of bond between the concrete slab and the steel sheet is actually reached. The study also included the development of a special-purpose software that facilitates design of composite slabs; a parametric investigation of the importance of m-k values in slab design is presented in the last part of the paper.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제42권3호
• /
• pp.144-150
• /
• 2016

Objectives: We compared the transbuccal and transoral approaches in the management of mandibular angle fractures. Materials and Methods: Sixty patients with mandibular angle fractures were randomly divided into two equal groups (A, transoral approach; group B, transbuccal approach) who received fracture reduction using a single 2.5 mm 4 holed miniplate with a bar using either of the two approaches. Intraoperatively, the surgical time and the ease of surgical assess for fixation were noted. Patients were followed at 1 week, 3 months, and 6 months postoperatively and evaluated clinically for post-surgical complications like scarring, infection, postoperative occlusal discrepancy, malunion, and non-union. Radiographically, the interpretation of fracture reduction was also performed by studying the fracture gap following reduction using orthopantomogram tracing. The data was tabulated and subjected to statistical analysis. A P -value less than 0.05 was considered significant. Results: No significant difference was seen between the two groups for variables like surgical time and ease of fixation. Radiographic interpretation of fracture reduction revealed statistical significance for group B from points B to D as compared to group A. No cases of malunion/non-union were noted. A single case of hypertrophic scar formation was noted in group B at 6 months postsurgery. Infection was noted in 2 patients in group B compared to 6 patients in group A. There was significantly more occlusal discrepancy in group A compared to group B at 1 week postoperatively, but no long standing discrepancy was noted in either group at the 6 months follow-up. Conclusion: The transbuccal approach was superior to the transoral approach with regard to radiographic reduction of the fracture gap, inconspicuous external scarring, and fewer postoperative complications. We preferred the transbuccal approach due to ease of use, minimal requirement for plate bending, and facilitation of plate placement in the neutral mid-point area of the mandible.

• 지구물리와물리탐사
• /
• 제27권1호
• /
• pp.1-22
• /
• 2024

2050 탄소중립을 달성하기 위해 현재 전 세계적으로 이산화탄소 포집·활용·저장(Carbon Dioxide Capture Utilization and Storage, CCUS) 기술이 주목받으면서, 북미, 북해, 중동, 오세아니아 지역을 중심으로 다양한 대규모 이산화탄소 포집·저장(Carbon Dioxide Capture and Storage, CCS) 사업이 활발하게 추진되고 있다. 2050년까지 연간 3,000만 톤급의 국내 저장소 확보가 중요한 국내 상황을 고려하여, 판구조론적 관점에서 해외 대규모 이산화탄소 저장소의 형성 과정과 지질구조 특징을 분석하고자 한다. 이를 위하여 해외 대규모 CCS 프로젝트를 개발 중인 북미, 북해, 오세아니아, 중동 지역의 이산화탄소 저장소의 형성 과정을 GPlates 프로그램을 활용하여 판구조론적인 관점으로 해석하였다. 또한, 각 지역을 대표하는 지중저장소에 대한 탄성파 영상화 결과를 지질구조적 측면에서 해석함으로써, 향후 국내 대규모 저장소 탐사에 활용할 수 있다.

• 비교문화연구
• /
• 제46권
• /
• pp.143-171
• /
• 2017

본 연구는 라틴아메리카의 일부 지역인 안데스와 리버플레이트 지역에서 양보접속사구로 기능하는 [todavía que]에 대한 형태-통사적 그리고 의미적 특성을 연구하고자 한다. Real Academia $Espa{\tilde{n}}ola$(2009)에 따르면 부사 todavía는 초점과 관련된 다양한 맥락에서 사용되며 특히 안데스와 리버플레이트 지역에서는 [todavía que]가 양보구문을 형성하며 첨가적 해석을 갖는다고 한다. 케추아어의 접미사 '-raq'과 아이마라어의 접미사 '-raki '는 스페인어의 부사 todavía와 동일한 의미를 갖는다. 그러나 이 두 원주민 언어에서는 상기의 접미사가 첨가 초점사의 기능을 수행하지만 스페인어에서는 첨가 초점사로 쓰이는 접미사는 없으므로 이러한 범주적 불일치로 인해 [todavía que]구조에서는 todavía가 부사의 형태로 접속사 que와 함께 첨가 초점사로 사용된다. 본 연구는 이러한 형태-통사적 그리고 의미적 특성은 두 원주민어들과 스페인어의 언어접촉 현상에서 비롯된 것으로 주장한다. 또한 이러한 주장에 기초하여 스페인어의 부사 todavía가 어원적으로 전칭양화사와 관련되는 사실과 척도와 관련된 자질을 내포하는 특성에 기인하여 [todavía que]는 척도 첨가의 의미를 갖는 양보의 접속사로 기능한다고 주장하고자 한다.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
• /
• pp.357-360
• /
• 2009

The present study focused on the segmented cell which has the similar performance to unaltered (not segmented) cell in real operating condition. Many literatures have been made the segmented cell to observe the behavior of local current density distribution in the single cell. However, it has been lack of scheme to segment the cell in that the detailed interpretation of segmenting in analytic point of view was insufficient. Hence, the basic idea of segmenting was introduced to determine the component to be segmented in anode side of unit cell. The electrical contact/bulk resistance was measured by using four wire/probe method through each part of cell components including MEA, GDL, Bipolar Plate and Current Collector. Electron transport mechanism was predicted by comparing resistance values which were obtained from the experiment. As a result, this offered a great benefit to segment the cell efficiently. With this method further experiments would be conducted in research areas which require current density distribution at the same operating condition as unaltered cell.

• 한국산학기술학회논문지
• /
• 제12권2호
• /
• pp.588-593
• /
• 2011

프로그레시브 노칭과 포밍금형에 있어서 박판성형해석에 의한 사전 분석은 제품을 양산하는데 꼭 거쳐야 하는 필수과정이다. 본 논문에서 연구한 Ez5는 일본 S 자동차의 미국 현지 공장에서 발주한 수출 금형을 가지고 스트립 레이아웃 설계에 관한 것을 연구한 것이다. 광폭 1열 1개 뽑기의 편측캐리어를 단 배열로 블랭크 레이아웃을 최적화하여 13개 공정으로 된 스트립 레이아웃설계를 완성하였다. 이런 형태의 금형수주는 앞으로 동시 다발적이고, 매우 빈번히 인터넷 공간상에서 발생할 것이며 금형에 대한 기술력을 갖춘 업체는 이러한 방식에 대응할 준비를 갖추어야 할 것이다.

• 한국환경과학회지
• /
• 제23권6호
• /
• pp.1067-1074
• /
• 2014

Life Cycle Assessment(LCA) has been carried out to evaluate the environmental impacts of glass bottle recycle. The LCA consists of four stages such as Goal and Scope Definition, Life Cycle Inventory(LCI) Analysis, Life Cycle Impact Assessment(LCIA), and Interpretation. The LCI analysis showed that the major input materials were water, materials, sand, and crude oil, whereas the major output ones were wastewater, $CO_2$, and non-hazardous wastes. The LCIA was conducted for the six impact categories including 'Abiotic Resource Depletion', 'Acidification', 'Eutrophication', 'Global Warming', 'Ozone Depletion', and 'Photochemical Oxidant Creation'. As for Abiotic Resource Depletion, Acidification, and Photochemical Oxidant Creation, Bunker fuel oil C and LNG were major effects. As for Eutrophication, electricity and Bunker fuel oil C were major effects. As for Global Warming, electricity and LNG were major effects. As for Ozone Depletion, plate glasses were major effects. Among the six categories, the biggest impact potential was found to be Global Warming as 97% of total, but the rest could be negligible.