• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2001년도 춘계학술발표회요약집
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• pp.441-441
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• 2001

• 한국작물학회:학술대회논문집
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• 한국작물학회 1998년도 춘계 학술대회지
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• pp.89-90
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• 1998

• Journal of Radiation Protection and Research
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• 제42권4호
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• pp.197-204
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• 2017

Background: X-ray imaging detectors for the nondestructive cargo container inspection using MeV-energy X-rays should accurately portray the internal structure of the irradiated container. Internal and external factors can cause noise, affecting image quality, and scattered radiation is the greatest source of noise. To obtain a high-performance transmission image, the influence of scattered radiation must be minimized, and this can be accomplished through several methods. The scatter rejection method using an anti-scatter grid is the preferred method to reduce the impact of scattered radiation. In this paper, we present an evaluation the characteristics of the signal and noise according to physical and material changes in the anti-scatter grid of the imaging detector used in cargo container scanners. Materials and Methods: We evaluated the characteristics of the signal and noise according to changes in the grid ratio and the material of the anti-scatter grid in an X-ray image detector using MCNP6. The grid was composed of iron, lead, or tungsten, and the grid ratio was set to 2.5, 12.5, 25, or 37.5. X-ray spectrum sources for simulation were generated by 6- and 9-MeV electron impacts on the tungsten target using MCNP6. The object in the simulation was designed using metallic material of various thicknesses inside the steel container. Using the results of the computational simulation, we calculated the change in the scatter-to-primary ratio and the signal-to-noise ratio improvement factor according to the grid ratio and the grid material, respectively. Results and Discussion: Changing the grid ratios of the anti-scatter grid and the grid material decreased the scatter linearly, affecting the signal-to-noise ratio. Conclusion: The grid ratio and material of the anti-scatter grid affected the response characteristics of a container scanner using high-energy X-rays, but to a minimal extent; thus, it may not be practically effective to incorporate anti-scatter grids into container scanners.

• 한국산학기술학회논문지
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• 제18권4호
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• pp.43-49
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• 2017

최근 국내 건설 분야에서 BIM의 활용이 늘어나고 있는 추세이지만 도면을 포함하는 BIM 설계가 아닌 주로 내 외부 시각화와 같은 단순 활용에 그치고 있다. 이에 대한 원인으로 여러 연구에서 BIM 설계에 필요한 라이브러리의 부족과 경제적인 문제를 지적하고 있다. 즉, 경제적으로 영세한 대다수의 국내 설계사무소 입장에서는 필요한 BIM 라이브러리를 직접 제작하여 사용하기 위한 비용과 인력 투자가 힘들어 BIM 설계 활성화에 부정적 요인으로 작용하고 있다. 따라서 라이브러리를 경제적이며 쉽고 빠르게 공급받을 수 있다면 BIM 설계가 보다 적극적으로 이루어 질 수 있을 것이다. 본 연구에서는 기존 건축자재선정업무와 BIM 라이브러리를 고찰하여 경제적이며 쉽고 빠르게 BIM 라이브러리 서비스를 제공할 수 있는 BIM 라이브러리 비즈니스 모델과 고려요소들을 제시하였다. 제시한 비즈니스 모델은 국내에서 절대적으로 부족한 BIM 라이브러리 공급자를 늘려 적은 비용과 노력으로 효과적인 BIM설계가 가능하도록 할 것이다. 본 연구에서 제시한 비즈니스 모델을 반영한 서비스가 이루어진다면 설계, 시공, 유지관리 단계에서 일관된 정보공유가 가능한 통합데이터베이스가 구축될 것이다. 구축된 데이터베이스를 이용하면 건축물의 생애주기 동안 자재 및 설비 정보의 변화를 모니터링할 수 있기 때문에 자재 및 설비의 개량은 물론 효과적인 설계와 유지관리를 위한 실적데이터로 활용될 수 있을 것이다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.3237-3250
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• 2011

As the growing concern about environment and earthquake for the concrete structure, many seismic rehabilitation and retrofitting methods have recently been studied but they are not coping enough with the changes of structure, specificly various problems have been found in seismic rehabilitation method - both in exposure or non exposure - when they are implemented to the underground structure, utility conduit, water supply facilities, underground wall, parking lot, road pavement, and elevated structure etc. This study is about the seismic rehabilitation method using environmentally friendly functional inorganic mortar and resilient material, and it is effectively retrofitted seismic performance as it reinforces not only physical strength, but also flexural and bond strength from the resilient material, and it has been analyzed and evaluated when the environmentally friendly functional inorganic mortar and the resilient material are applied so as to countermeasure the effect of earthquake and viable problems and approved for possibility of various applications and wide use.

• 대한기계학회논문집A
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• 제21권9호
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• pp.1441-1451
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• 1997

This paper addresses method which can be used for analyzing thermal stresses of a functionally graded material(FGM) using semi-analytical approach. FGM is a nonhomogeneous material whose composition changes continuously from a metal surface to a ceramic surface. An infinite one dimensional FGM plate is considered. The temperature distribution in the FGM is obtained by approximate Green's function solution. To expedite the convergence of the solutions, alternative Green's function solution is derived and shows good agreement with results from finite difference method. Thermal stresses are calculated using temperature distribution of the plate.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 추계 학술논문 발표대회
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• pp.17-18
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• 2015

In the case of concrete recently manufactured with a concrete mixing truck, although aggregate and cement are used as the main ingredients, from a costs savings perspective, low quality aggregates are processed and used as concrete aggregate. In the case of these low quality aggregates, the unit volume and unit binder weights are increased for manufacturing, and due to this problems such as dry shrinking of the architecture and economic infeasibility have arisen. Therefore by changing the aggregate material and the unit binder weights that are currently being distributed, this research analyzes the influence on concrete.

• KIEAE Journal
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• 제15권6호
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• pp.11-18
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• 2015

Purpose: The current study analyzed trends in thermal insulation performance with aging, and condensation characteristics caused by the former. Method: Thermal insulation and condensation prevention performance of an architecture were assessed using Temperature Difference Ration Inside, or TDRi. Subjects of this quantitative analysis in thermal insulation performance change due to aging included recently constructed apartments and aged apartments older than 40 years. Time series comparison and analysis were conducted to observed changes in the thermal insulation performance and condensation characteristics. Result: Analysis showed that wall insulation performance degraded with aging regardless of fortified insulating material usage or insulating material type, which caused increased danger of condensation. In addition, when fortified insulating material was installed on the connection between the walls, insulation performance degradation was lower compared to cases in which fortified materials were not used. In all cases from 1 to 10, the rate of thermal insulation performance degradation increased after 20 years of aging.

• Tribology and Lubricants
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• 제16권1호
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• pp.15-21
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• 2000

Radiation of Nd-YAG laser changes and refines the surface microstructure of steels, which gives rise to enhancement of hardness and resulting wear resistance. In the present work, the effect of processing parameters during the surface modification with laser on the wear behavior of the SM45C steel was studied by means of wear testing. The counter material was alumina ceramics. The microstructure observation revealed the dependence of molten depth and width on the defocusing distance. The laser modification of steel surface give rise to improved wear resistance in the testing speed range of either <0.2 m/s or >0.9 m/s Material transfer from steel was wear observated the surface of counter material when testing speed was lower than 0.7 m/s.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 유기절연재료 방전 플라즈마연구회
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• pp.1-5
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• 2003

This paper presented the effects of accumulation of surface charges on hydrophobicity level and the surface states of silicone polymer used for outdoor insulator treated by ultraviolet irradiation and corona discharge through measuring surface voltage decay of a corona-charged specimen were investigated. The surface resistivity by the method of the surface potential decay was compared with the value by the three electrodes methods. From this study, it was found that the accumulation of surface charges above a critical surface voltage on silicone insulating materials could lead to the temporary loss of surface hydrophobicity. In addtion, uv stress lead to a longer decay time of surface charges. We could conclude that the effects of surface charges on hydrophocity level and the changes of surface state by various artificial treatments were understood through a trend of surface potential decay.