• Journal of the Korean Society for Precision Engineering
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• v.20 no.5
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• pp.156-163
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• 2003

In order to investigate the possibility of punching process of brittle material by ball impact, the effects of sealing materials about impact damage of soda-lime glass by small spheres were evaluated experimentally. The using of sealing materials in the development of perfect cone crack was more effective than no using of sealing materials. At the sealing materials condition, in the case of 5mm-thick specimen, Copper and PMMA sealing were more effective in producing a perfect cone formation than the other sealing materials. And in the case of 8mm-thick specimen, Aluminum sealing was most effective in producing a perfect cone formation. The impact velocity range over which perfect cones were formed was influenced by both the thickness of specimen and sealing materials. By a proper selection of sealing materials, the application fur industrial technology for hole (or nozzle) punching process of brittle materials is expected.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.2
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• pp.301-321
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• 2019

The development of a rapidly hardening seal material applicable to steel pipe multistage grouting is described in this paper. In the multistage technique, seal materials are inserted to prevent the backflow of main grouting material. The grouting material must be inserted only after sufficient time has passed for the seal material to reach a gel state. Otherwise, the fluid seal material mixes with the main grouting material and a backflow of the grouting material occurs, thereby making its in situ insertion difficult. Furthermore, if the seal material remains in the gel state for too long a time, it solidifies; and the main grouting material will not be able to seep into the soil. The gel time, i.e., the time needed for the fluid seal material to turn into a gel state, determines the construction period of steel pipe multistage grouting. The gel time is one of the important factors in this technique, because it impacts the total tunnel construction period significantly. This study develops a rapidly hardening calcium aluminate material, which can reduce the gel time and shorten the construction period while retaining proper sealing function. It also presents a method to determine whether the seal material has reached the gel state as well as the quality standard and bleeding rate testing method for the seal material in the gel state.

• Proceedings of the Materials Research Society of Korea Conference
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• 2005.05a
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• pp.168-168
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• 2005

• Korean Journal of Materials Research
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• v.8 no.12
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• pp.1121-1126
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• 1998

For vacuum seated panel, stresses and displacements in the glass plate were calculated. The geometric variables for our experiment were the thickness of glass plate, the size of panel and the width of sealing line. The fracture behaviors and displacements of its under the vacuum were measured. From the measurement of strains and fracture, it was considered that the maximum stress acted at the middle of the sides of the panel. The stresses and displacement distribution of manufactured panels were greatly dependent on the width of the sealing line in the panel. The measured values are more similar to the values which were calculated from the condition of built-in edge as the width of the sealing line is larger. The measured displacement of the panel, made of 3mm thick glass plate, with size of $80\Times120\textrm{mm}^2$ and 20mm sealing line was $57\mu\textrm{m}$. This value is similar to calculated value, $54\mu\textrm{m}$, from built- in edge condition in the finite element method.

• Proceedings of the Materials Research Society of Korea Conference
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• 2005.05a
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• pp.139-139
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• 2005

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.5
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• pp.1161-1171
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• 1993

Model materials are developed to achieve similarity of flow patterns for mild steels in forming processes at high temperatures. The model materials consist of pure plasticine and one or two additives such as resin and lanolin. To verify the similarity of flow patterns between physical modeling and compression of mild steels at high temperatures, ring and compression tests have been carried out with the developed-model materials at various strain rates, temperatures and lubricants. The test results are in good agreement with the flow patterns obtained from upsetting of a mild steel at high temperatures.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.1
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• pp.187-192
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• 2021

In this study, Inconel 625 was used as a thermal spray material to prevent dew point corrosion damage to the economizer tube, and sealing treatment was performed after applying the arc thermal spray coating technology. Various electrochemical experiments were conducted in the 0.5 wt% sulfuric acid solution to analyze the corrosion resistance of the thermal spray coating (TSC) layer. After the anodic polarization experiment, the degree of corrosion damage was determined through a scanning electron microscope and EDS component analysis. When measuring the open circuit potential, the effect of the sealing treatment was confirmed through stable potential formation of the TSC+sealing treatment (TSC+Sealing). As a result of the anodic polarization experiment, the passivation region was confirmed in TSC and TSC+Sealing, and corrosion resistance was improved as no corrosion damage was observed. In addition, the corrosion resistance of TSC+Sealing was the best when analyzing the corrosion potential and corrosion current density calculated by Tafel analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.279-287
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• 2018

Sealants are an important element of modern architecture and serve as a building protection against weathering by providing barriers against ingress of moisture, air, and other materials. Exposure to a variety of environments often reduces lifespan due to changes in physical, chemical and mechanical characteristics, and UV, humidity, and temperature expansion are important issues that are directly related to durability. In this study, a combined deterioration test chamber was developed to simulate the environment of the open air as an instrument for verifying the durability of structural sealing materials indoors. In order to replicate special weather conditions, such as yellow dust, acid rain, and contamination by microorganisms, it was deemed impossible to replicate the outdoor environment by 100 %, and the results of the results of the results of the external exposure test of the structural sealant and the combined deterioration testing device. As a result of the displacement test of the outdoor exposure test, it was determined that the sealant was breaking apart and that it would be smooth, and the displacement would be up to three times greater than the initial material value of 1 year. The displacement test results of the combined deterioration test device show the tendency to deteriorate, decreasing the elasticity and tensile characteristics. In the case of denatured silicon, the current 400 cycles have been completed to confirm 12 months of degradation of the external exposure. The deformation of the test specimen cannot be verified with the naked eye, so it is considered that the conditions of the specimen are more stable than the silicon sealant. As a result of the outdoor exposure test, if the combined deterioration test device is structured and proposed in the relevant guidance or specification, the anticipated lifespan of 12 months in the actual use environment can be verified indoors and below 3 months later, economically.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.206-207
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• 2005

Display 소재로서 유전체나 격벽재 실링재로 사용되고 있는 frit는 PbO를 주성분으로 갖는 유리가 사용되고 있다. PbO 성분이 함유된(50$\sim$85%) 구성소재는 최근 RoHS 나 WEEE 등의 환경규제 실행에 직면해 있으며, 대체재료의 개발을 위한 많은 연구가 진행되고 있다 PbO 성분을 대체할 성분으로는 $Bi_2O_3$ 계, BaO-ZnO 계, $P_2O_5$ 계 등의 성분이 주요성분으로 이루어져 있으며, PbO 성분을 함유한 유리의 저융점, 저유전율, 고 투과율, 내산성, 내전압, 팽창계수 matching 등의 특성들에 부합되는 재료를 개발하기 위해 많은 노력을 기울이고 있다. 본 연구에서는 SnO-$P_2O_5$ 계 유리 조성을 선택하여 $R_2O_3$의 치환 및 용융분위기의 조절에 따른 저융점 유리로서의 특성과 효과에 대하여 고찰하였다.

• The monthly packaging world
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• s.207
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• pp.111-125
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• 2010

최근 포장 분야 가운데 가장 빠르게 성장하는 분야의 하나로 플렉시블 패키지에 대한 인식이 커지고 있다. 미국 내 포장산업 분야의 경우, 플렉시블 패키지는 약 절반가량을 차지하는 수요를 차지하고 있다. 우리나라의 경우도 경제성과 다양한 기능성을 제공하는 플렉시블 패키지는 활용 범위가 확대되고 있다. 플렉시블 패키지의 개발이 이처럼 활발해지는 경향은 경쟁 재료와의 비용에 있어서 우위를 가지면서도 강도, 실링, 배리어 및 기타 포장 특성이 우수하고 높은 그래픽 적용성 등에 있어서 많은 장점이 강조되고 있다. 본 연구에서는 플렉시블 패키지의 개념과 국내외 현황을 고찰하고, 플렉시블 패키지의 기능을 분석하며, 앞으로의 동향과 과제를 도출하는데 목적이 있다. 연구 결과, 최근의 우수 사례와 선행연구들을 통해 본 플렉시블 패키지의 기능은 첫째, 사용의 편의와 소비자 측면에서의 구조적 기능, 둘째, 인쇄 및 시각적 측면의 그래픽 기능, 셋째, 혁신적 포장재 적용에 의한 재료적 기능, 넷째, 자원의 절감과 재료의 최소화, $CO_2$ 감소 및 에너지 절감 측면에서 미래에 더욱 중요성이 강조될 환경친화적 기능을 고찰하였다. 포장 분야 가운데 가장 빠르게 성장하는 분야의 하나로서 그 비중이 증가하고 있는 플랙시블 패키지에 대하여 새로운 재질의 적용, 마케팅 수단으로서의 패키지 기능, 소비자 요구에 따른 기능과 특성을 이해하고 앞으로의 과제를 고찰하는 것은 패키지디자인 분야의 연구에서 중요한 의미를 갖는다. 본 고에서는 (사)한국브랜드디자인학회가 발표한 제15호 논문 가운데 영산대학교 김미자 교수의 "플렉시블 패키지의 기능과 동향에 대한 연구"를 살펴보도록 한다.