• 환경영향평가
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• 제22권5호
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• pp.481-489
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• 2013

There are U.S. troops with a force about 290,000 strong stationed all around the world, approximately 150 countries. Among the troops, USFK has performed principal part with its stationing for 50 years against the military threat of North Korea. However, as a result of an investigation made into environmental contamination of several bases which were restituted from US to ROK by the Land Partnership Plan in the process of relocation of USFK, it was found that the area was contaminated by not only TPH and BTEX caused by diesel fuel and JP-8 but also various heavy metal over the standard level according to the operations of corps. Among these bases, 4 corps, each of which has different duties and function, were chosen to be analyzed for the characteristics and degrees of soil contamination. Fisrt of all, in armored camp the soil was contaminated by TPH and heavy metal (Zn, Ni, Pb) due to the repairing activities of tracked vehicles and shooting exercises. In army aviation camp, the soil was contaminated by TPH, BTEX and heavy metal (Zn, Cd) due to repairing activities of aircrafts. Also, in engineer camp there was contaminated area polluted by TPH and heavy metal (Zn, Pb) caused by open-air storage of various construction materials and TPH, BTEX and heavy metal (Zn, Pb, Cu) contamination of aircraft shooting area in shooting range camp were detected. Managing environment will be more effective when we identify the contaminative characteristics and take necessary measures in advance.

• 청정기술
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• 제22권4호
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• pp.232-240
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• 2016

최근 디스플레이 대형화 및 유연화로 인한 기존 ITO (indium tin oxide) 기반 TSP (touch screen panel)의 구현에 한계로 인한 대체 소재에 대한 다양한 연구가 진행 중이다. 기존 기술의 대체 소재로 메탈메쉬(Metal mesh) 방식에 대한 연구가 진행되고 상용화 수준까지 진행되었다. 그러나 시인성 및 모아레(Moire) 현상으로 인하여 $5{\mu}m$ 이하의 미세 전극 패턴이 필요하나 공정 중 패턴이 탈락하는 등의 문제로 낮은 수율의 문제가 있다. 기존의 레이저 CVD 리페어 공정에서 $10{\mu}m$ 이하의 패턴 형성의 한계, 위성액적 등의 문제로 인해 안정적인 미세전극 패턴 형성에는 어려움이 있었다. 본 연구에서는 $5{\mu}m$ 이하의 안정적인 패턴 형성을 위해서 다양한 점도에서 미세액적 토출이 가능한 전기수력학 프린팅 기술을 적용하였다. $5{\mu}m$ 이하의 안정적인 미세 전극 패턴 형성을 위해 주요 변수의 변화에 따른 최적 공정 조건을 도출하였고 최적 공정 조건을 입력하여 리페어 공정 적용 가능성을 확인하였다.

• 한국문화재보존과학회:학술대회논문집
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• 한국문화재보존과학회 2005년도 제22회 학술대회 발표 논문집
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• pp.179-184
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• 2005

Materials used for repairing and restoring both pottery and porcelain are practically organic, which makes the analysis procedure difficult in the course of time. It is, however, important in the field of conservation to analyze the material applied in the past. In consequence, this research will examine the components of the restoration materials collected in the process of ceramic conservation: the fillings using SEM-EDS and FT-IR; retouching materials; the adhesive used between the filling and retouching material.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.43-44
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• 2002

Langmuir-Blodgett mono- and multilayer films from 2,4-heneicosanedione have been examined as lubrication coatings In the process of wear. Tribological properties of the films have been studied by atomic force microscopy and microtribometer. It has been observed that the wear resistance of silicon surface coated with OTS/LB multilayer system increased by several orders of magnitude compared to uncoated surfaces at low normal load. The results obtained suggest that the system constructed on silicon surface reduces surface energy, friction coefficient and increases life of substrate due to a possibility of LB film self-repairing during frictional contact.

• Structural Engineering and Mechanics
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• 제62권3호
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• pp.291-295
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• 2017

The behaviour of reinforced concrete beams strengthened with near surface mounted (NSM) CFRP prestressed prisms was experimentally investigated. Five RC beams were tested under four point bending. All beams were made with dimensions of 300 mm in width, 2000 mm in length and 150 in depth. The effects of presstress level of CFRP prestressed prisms and prism material type were studied. The failure mode, load capacity, deflection, CFRP strain, steel strain and ductility of the tested beams were all analyzed. The results showed that the behavior of the reinforced concrete beams strengthened with NSM CFRP prestressed prisms showed a significant increase in the load-carrying capacity and the deformation capacity. The NSM CFRP prestressed prisms strengthening technique could be considered as an effective method for repairing RC structures.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.363-366
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• 2005

When widening or repairing concrete deck slab, there is a joint inevitably. However, joining-construction method have following problem, that is the additional stress in existing part of bridge resulting from the specific process of joining-construction and the difference of amount of shrinkage between new and existing bridge. On this study, compared shrinkage stress of the direct joining construction method with the indirect joining construction method, and concluded the proper substitution rate of expansion cement. The rate of replacement was proper at $10\%$. but more than $15\%$, concrete had excessive expansion and weeker compressive strength. The time of placing closure concrete, considering the shinkage stresses and creep, was suitable in $45\~60$ days after placing the new concrete deck slab.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기물성,응용부문
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• pp.210-213
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• 2005

This article describes an estimate method of the spark plug gap by measuring breakdown voltage. Breakdown voltage is the function of spark plug gap, pressure, temperature and humidify. However. It is dominated mainly by the spark plug gap. This technique is applied to in-line process test of the spark plug gap in automobile engine production. Breakdown voltage of normal spark plugs slightly scatters in ordinary conditions and if there is dust or burr in the gap, breakdown voltage gets lower. This technique saves repairing time for bad spark plug and attributes to improve the quality of automobile engine.

• International Journal of Concrete Structures and Materials
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• 제7권4호
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• pp.265-271
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• 2013

Prestressed concrete cylindrical pipe (PCCP) has been widely used for the distribution of water in communal, industrial, and agricultural systems for a long time. However, as it deteriorates, structural failures have been experienced. Replacing the entire existing PCCP with partial damages is not an economical method. Currently, as a cost effective repairing method, a new approach using fiber reinforced polymer (FRP) has been applied. A new design procedure of this method was proposed considering various kinds of loading condition. However, it is not easy to apply this method for design purpose due to its complex procedures. The objective of this study is to provide a new design criteria and process for PCCP rehabilitation with FRP. Through this method, the appropriate quantities of FRP layers will be decided after examining of limit states of deteriorated PCCP. For this purpose, two deterioration conditions are assumed; fully deteriorated and partially deteriorated. Different limit states for each case are applied to decide the quantities of attached FRP. The concept of "margin of safety" is used to judge whether the design results are within the optimal ranges to satisfy all limit states.

• 한국공간구조학회논문집
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• 제14권2호
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• pp.41-50
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• 2014

The stone pagoda of Mireuk temple site is currently restoring through the repairing process. This stone pagoda has the various construction types in the inner and outer space. Therefore, the stress concentration and structural behavior need to be considered through the analysis of various construction patterns. To this end, this study presents the structural modelling and analysis considering the discrete element analysis technique to solve the discontinuum behavior between the stone elements. Also, this study performs the structural performance evaluation through the various design variables for the safety of stone pagoda. Through the analysis results, we can find out the small stress concentration in the several members. But, because the stresses and displacements are relatively small, we can secure the safety of the whole structure.

• 대한산업공학회지
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• 제21권4호
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• pp.463-477
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• 1995

This paper presents a decision model that will estimate the expected number of failed units in a repair facility in accordance with the varying demand, and determine the required number of personnel for repairing components. The demand is related to the failure process which follows a reliability growth phenomenon in service. The information in this paper is useful for selecting appropriate scheduling rules and spares stocking policies. SIMAN and FORTRAN were used for computing the time dependent performance measures in the repair facility. The numerical integration method that is presented in this paper will provide accurate performance measures with any dynamic pattern of demand, service rates, and any number of servers.