• 접착 및 계면
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• 제22권2호
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• pp.69-77
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• 2021

세계적으로 지속가능한 세상을 만들기 위한 노력이 제조업에서 많이 이루어지고 있다. 이를 위해서는 사용 후 제품을 쉽고 간단하게 해체할 수 있는 설계 개념 중요하다. 접합된 제품 해체 시부품에 대한 피해가 없도록 접합부위가 분해되어 재활용이나 수리를 가능하게 하는 신기술이 최근 개발되고 있다. 본 총설에서는 조절가능한 접합-해체용 소재 기술, 특히 빛으로 해체하는 접착소재기술 동향을 정리하였다. 또한 반도체, 디스플레이 산업에 현재 활용되고 있는 빛 이용 임시 접합-해체용 필름에 대해 기술하였다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.668-674
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• 2002

Structural integrity assessment is indispensable for preventing catastrophic failure of industrial structures/components/facilities. This diagnosis of operating components should be done periodically for safe maintenance and economical repair. However, conventional standard methods for mechanical properties have the problems of bulky specimen, destructive and complex procedure of specimen sampling. Especially, the mechanical properties at welded zone including weldment and heat affected zone could not be evaluated individually due to their size requirement problem. So, an advanced indentation technique has been developed as a potential method for non-destructive testing of in-field structures. This technique measures indentation load-depth curve during indentation and analyzes the mechanical properties related to deformation such as yield strength, tensile strength and work-hardening index. Also indentation technique can evaluate a residual stress based on the concept that indentation load-depth curves were shifted with the direction and the magnitude of residual stress applied to materials. In this study, we characterized the tensile properties and welding residual stress of various industrial facilities through the new techniques, and the results are introduced and discussed.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2001년도 춘계학술발표대회 논문집
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• pp.135-140
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• 2001

A post-tensioned reinforced concrete slab bridge is analyzed by specially orthotropic laminate theory. Symmetrically reinforced slab with tension and compression steel is considered for convenience of analysis. Each longitudinal and transverse steel layer is regarded as a lamina, and material constants of each lamina is calculated by the use of the rule of mixture. This bridge is under uniformly distributed vertical loads, and axial loads and end moments due to post-tensioning. In this paper, finite difference method is used for numerical analysis of this bridge. Theory and analysis method of specially orthotropic laminate plates used in this paper can be used for design of new bridges, and maintenance and repair of old bridges.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2001년도 춘계학술발표대회 논문집
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• pp.141-146
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• 2001

A post-tensioned steel plate girder bridge with cross-beams is analyzed by specially orthotropic laminate theory. The cross-sections of both girders and cross-beams are WF types. The result is compared with that of the beam theory. This bridge with simple support is under uniformly distributed vertical load, and axial loads and moment due to post-tension. In this paper, finite difference method for numerical analysis of simple supported bridge is developed. Relatively exact solution is obtained even with small number of meshes. Theory and analysis method of specially orthotropic laminate plates used in this paper can be used in design of new bridges, and maintenance and repair of old bridges.

• Coupled systems mechanics
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• 제9권5호
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• pp.473-498
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• 2020

This paper presents a careful theoretical investigation into interfacial stresses in reinforced concrete foundation beam repairing with composite plate. The essential issue in the analysis of reinforced structures with composite materials is to understand the individual behaviour of each material and its interaction with the remaining ones. The present model is based on equilibrium and deformations compatibility requirements in and all parts of the repaired RC foundation beam, i.e., the reinforced concrete foundation beam, the composite plate and the adhesive layer. The theoretical predictions are compared with other existing solutions, By comparisons between the existing solutions and the present new solution enable a clear appreciation of the effects of various parameters such as the geometric characteristics and mechanical properties of the components of the repaired beam, as well as the geotechnical stresses of the soil are considered. This research is helpful for the understanding on mechanical behaviour of the interface and design of the composite-concrete hybrid structures.

• 한국환경농학회지
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• 제9권1호
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• pp.61-68
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• 1990

The pressure to develop new agricultural technologies will be roughly proportional to the rate of depletion of natural resources employed in agriculture. Of these resources, land, water and gentic resources are critical. The development of agriculture is associated with a scientific and technological establishment, of remarkable capability ; responding rapidly to many problems encountered by the agricultural production. These advantages are also coupled with constraints. Agricultural systems are concerned with the efficient conversion of resources into products that are wanted by the producer or someone else who is prepared to pay for them. They are based on biological processes, but they are operated by the people for a multiplicity of purposes. Study of agricultural systems is aimed at helping in the operation of systems, their repair or their improvement. The future concerns of agriculture will center on (1) increasing and safeguarding the supplies of productive inputs to agriculture, (2) improving the efficiency with which these inputs are used in food production, (3) developing new sources of basic food materials, and (4) coping with the external costs that tend to appear in intensive, mechanized agriculture.

• 한국농촌건축학회논문집
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• 제13권1호
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• pp.37-44
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• 2011

The maintenance works for brick-structured buildings are a new field in Korea, and practical cases are yet inadequate so that such works may cause adverse effects of damaging the buildings after all. Therefore, this study has extracted a preservation technology believed to be most desirable in minimizing the damage to the original state of the buildings and preserving the value as the cultural assets through maintenance work details from 1986 to 2010 regarding brick-structured buildings designated as cultural properties. Firstly, a brick replacement method of using the brick used at the time of construction is efficient in replacement and repair of brick material for preserving value of cultural assets and minimizing damage of the original form. Secondly, use of lime mortar through material analysis is effective in repair of masonry joint and mortar but it is not used often due to high experimental cost. Finally, reinforcement of structure using a form for a building with severe damage is most efficient when considering additional problems. However, damage on the original form of a building can be minimized and value of a building can be preserved only when consideration on sufficient case analysis, materials to be used, and conditions of a building is supported.

• 한국구조물진단유지관리공학회 논문집
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• 제7권1호
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• pp.279-288
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• 2003

This study is the development of method on repairing concrete structure for progressing the durability of reinforced concrete. This method is wet spray method which compress and conduct mortar pre-mixed with polymer powder to hose by high pressure pump and spray it on the section of concrete structure through nozzle made specially. Characters of this method are that materials are selected with the sort of structure and the cause of deterioration and macro pores are removed in repaired section by conducting with high pressure and spraying with high velocity for progressing the durability of concrete structure. This study has carried out that the minimum capacity of rebound was measured with various condition and physical properties of sample made by spray method were estimated in comparing with sample made by previous hand method. Also, properties of long-term have carried out after this method was applied on site. According to experimental study, the capacity of rebound showed below 5% and physical properties of sample made by spray method were superior to that of sample made by hand method and physical and durable properties of long-term showed excellence.

• Computers and Concrete
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• 제12권4호
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• pp.553-563
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• 2013

The present study aims to show how the problem of reproducing, as closely as possible, binders of historic mortars by mixing raw materials which are commercially available, can be formulated as a linear optimization problem. The study points out that by mixing five standard raw materials (end-members) it is possible to obtain mortar binders with the almost same chemical compositions of those determined on the historic and archaeological mortar samples studied in some recent scientific papers. An advanced function of the Microsoft Excel spreadsheet, the Solver add-in, was used for the calculation of the right amount of each raw material to be mixed for producing the new binders. This approach could be useful to provide an optimal solution in the process of restoration of ancient monuments, where it is necessary to replace the historic mortars with new highly compatible repair mortars.

• Restorative Dentistry and Endodontics
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• 제25권2호
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• pp.159-169
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• 2000

The purpose of this study was to examine the tissue response to experimental furcation perforations immediately treated with Super EBA, Ketac Silver, MTA and Emdogain using surgical microscope. Forty experimental furcation perforations were created in the mandibular and maxillary premolars and molars of 4 adult dogs and immediately repaired with experimental materials. The animals were sacrificed after 16 weeks and radiographic and histologic results were evaluated. The results were as follows. 1 All materials tested in this experiment revealed a certain degree of extrusion of the filling materials and infiltration of inflammatory cells into the periodontal space. Except MTA group, epithelial down-growth of the surrounding gingiva was found in all experimental groups. 2. Both Ketac Silver and Emdogain group showed the greatest degree of inflammatory reaction and bone resorption. 3. Super EBA group showed moderate inflammation and newly bone formation under the perforation area. 4. MTA group showed minor inflammation, new bone regeneration toward restorative materials and partially cementum growth onto the surface of the material. This group demonstrated a favorable prognosis.