• 전력전자학회논문지
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• 제6권5호
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• pp.394-399
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• 2001

반도체 생산 공정에 있어, 저압 화학적 기상 증착(Low Pressure Chemical Vapor Deposition)과 프라즈마 강화 화학적 기상 증착(Plasma Enhanced Chemical Vapor Deposition) 공정 후 발생된 환경 유해 가스를 효과적으로 세정하기 위한 장비인 건식 세정기(dry scrubber)의 전원장치에 대한 연구이다. 주 전력회로는 1500W, 스위칭주파수 100kHz의 위상 변위 풀 브리지(Phase Shift Full-Bridge)방식의 인버터와 100kHz 저역 통과 필터 및 임피던스 변환기로 구성되었다 모드해석과 모의실험을 통하여 회로방식의 타당성을 확인하였고 50$\Omega$ dummy load 및 chamber 실험을 통하여 다양한 부하조건에서도 프라즈마를 안정되게 발생시킬 수 있음을 확인하였다.

• 건축역사연구
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• 제23권1호
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• pp.7-19
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• 2014

This study considers the proper repair techniques by examining the most representative repair cases of the Korean arch bridges and proposes the constructional manual which can apply similar occasions. The cases are Seonamsa Seungseongyo and Songgwangsa Geukrockgyo where this researcher had taken part in the repair works. This Study proposes the maintenance construction manual about the performance degradation drew by performance degradation of the both Korean arch bridges in the maintenance process. First, arch bridge maintenance should be carried out in the dry season, when water is impermeable in the bottom surface of the bridge. Moreover, risk factors of the maintenance should be excluded to secure the water vally flow, the bypass and the temporary bridge. Second, prior to repair, it has to precede (1)3D shooting (2)formal examination (3)structure safety test (4)geological and lithic surveys (5)arch curvature establishment and makeshift frame settlement before transformation (6)relationship expert comments. Third, if the baduk and the foundation stones are inevitable to replace due to performance degradation on the foundation, it should use the high quality stones and secure greater stress by extending the standard range. The foundation on irregular rock needs to be flattened and underside on the replaced materials require Grengyijil to deliver the equal loads. Fourth, In the process of dismantling the stones of the arched bridge, it could make heavy weathering degree and not reuse the materials. Charge should converge the expert advices to choose the reuseable, the conservate and the alternative materials, and increase the reutilization of the raw materials by preservation and reinforcement treatments. Fifth, the side wall should be repaired by the rubble work technique which is not able to pile compost satiety, so it must use long depth of masonary stones for reinforcement. It is considered to reinforce the stone wall in shore as much as possible and protect the abutment and the side wall on the upstream for the arch bridge maintenance works.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 추계학술발표대회 논문집
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• pp.236-240
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• 2009

Dry wall using steel stud has the advantage of possibility to install various building, so it used to many buildings inside and outside of the country very rapidly. Though Light gauge steel framed housing offers many advantages to the consumer and the builder, the use of steel studs in wall system cause thermal problems such as thermal performance and pattern staing on walls. The present study has been conducted to observe effect of stud by the shape, and two kind of stud is made for this test to compare thermal performance. The test was conducted by setting those stud on the chamber and heating them. As the results of test and photograping by using TVS, there was temperature gap of each stud, and surface temperature of each section was appeared differently due to shape of stud delaying thermal bridge.

• 한국물환경학회지
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• 제24권3호
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• pp.378-382
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• 2008

During the dry periods, many types of pollutants are being accumulated on the paved surface by vehicle activities and the accumulated various pollutants are inflowing into the near watershed areas for the rainfall periods. Particularly, bridges are the centralized region to be the surface runoff of the stromwater due to the high ratio of the impermeable area. Also, the metals, toxic chemicals and sediments originated from bridges could be strongly influenced to the watershed areas during the runoff. Therefore, the present study is achieved to provide washoff characteristics and correlation from the bridge during rainfall periods. The result shows that the EMC ranges for 95% confidence intervals in a bridge land use are 10.12~128.09 mg/L for TSS, 6.07~21.15 mg/L for BOD, 2.10~6.70 mg/L for TN and 0.06~0.85 mg/L for TP.

• Structural Engineering and Mechanics
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• 제19권2호
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• pp.173-184
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• 2005

For reducing construction cost, two-plate-girder bridges are getting popular in Japan. This type of bridge employs a PC slab, which is often cast-in-place. In such a case, concrete is not usually cast over the whole slab at one time: some portions are constructed earlier than the rest. Therefore, a construction joint is inevitably created. Due to the drying shrinkage of concrete, tension stress may occur in concrete slab. High tensile stress can be expected near the construction joint where concretes with different ages meet. Moreover, prestressing is not applied over the whole length of slab at one time. This may also serve as a source of tensile stress in the slab. Thus there is a chance that cast-in-place PC slab, especially near the construction joint, may be subjected to tensile cracking. In the present study, stress states near the construction joint in the cast-in-place PC slab of a two-plate-girder bridge are investigated numerically. The finite element method is employed and the three-dimensional analysis is conducted to see the influence of dry shrinkage and prestressing. The stress states in the PC slab thus obtained are discussed. The simplified model of a plate girder for this class of analysis is also proposed.

• 콘크리트학회논문집
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• 제14권4호
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• pp.556-565
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• 2002

콘크리트 교량 바닥판은 건조수축 및 온도변화 등에 의하여 초기 일차균열이 발생하고, 사용기간 동안 반복되는 차량하중의 크기와 철근 간격 등에 의하여 초기 균열이 이방향 균열로 점차 진전하게 된다. 바닥판의 거동을 효율적으로 향상시키기 위해서는 보강방향에 대한 고려가 필수적이다. 따라서 본 연구에서는 탄소섬유쉬트를 보강재로 사용한 경우의 보강된 바닥판에 대한 비선형 유한요소해석을 실시하였으며, 해석의 정확성을 높이기 위하여 보강된 바닥판의 경계조건과 재료성질을 시험조건과 부합될 수 있도록 모사하였다. 보강방향과 보강량에 대한 해석결과는 시험결과와 비교, 분석함으로써 정확성을 검증하였으며, 이와 함께 보강된 바닥판의 효율성을 검증하기 위하여 보강재량, 폭과 두께 등과 같은 보강변수에 의한 보강후의 구조적 효율성을 고찰하였다.

• Structural Engineering and Mechanics
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• 제65권2호
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• pp.203-211
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• 2018

This paper introduces the development process of NCC(New Concrete Cutting) system and analyzes first verification test. Based on the first verification test results, some problems of NCC system have been newly modified. We carry out the second verification test. We tried to verify cutting performance and dust control efficiency of NCC system through the cutting test of concrete bridge piers. In particular, this verification test strives to solve the problem of concrete dust, which is the biggest problem of dry cutting method. The remaining dust problems in cutting section tried to solve through this verification test. This verification test of the NCC system shows that the dust problem of dry cutting method is closely controlled and solved. In conclusion, the proposed NCC method is superior to the dry cutting method in all aspects, including cutting performance, dust vacuum efficiency and cooling effect. The proposed NCC system is believed to be able to provide eco-friendly cutting technology to various industries, such as the removal of the SOC structures and the dismantling of nuclear plants, which have recently become a hot issue in the field of concrete cutting.

• 대한건축학회논문집:구조계
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• 제35권6호
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• pp.153-164
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• 2019

The presence of thermal bridges in a building envelope cause additional heat loss which increases the heating energy. Given that a higher building insulation performance is required in these cases, the heat loss via thermal bridges is a high proportion of the total heat energy consumption of a building. For the dry exterior insulation system that uses mullions and transoms to fix insulation and exterior materials such as stone and metal sheet, the occurrence of thermal bridges at mullions and transoms is one of the main reasons for heat loss. In this study, a dry exterior insulation system using the truss insulation frame (TIF) was proposed as an alternative to metal mullions. To evaluate the building envelope performance, structural, air-leakage, water-leakage, fire-resistance, thermal, and condensation risk tests were conducted. In addition, the annual energy consumption associated with heating and cooling was calculated, including the linear thermal transmittance of the thermal bridges. As a result, the dry exterior insulation system using TIF achieved the allowable value for all tests. It was also determined that the annual heating load of a building was reduced by 36.7 % when the TIF dry exterior insulation system was used, relative to the dry exterior insulation system using steel pipes without additional insulations.

• 한국안전학회지
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• 제23권4호
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• pp.59-66
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• 2008

Recently, the deterioration of reinforced concrete structures, primarily due to corrosion of steel reinforcement, has become a major concern. Chloride-induced deterioration is the most important deterioration phenomenon in reinforced concrete structures in harsh environments. For the realistic prediction of chloride penetration into concrete, a mathematical model was developed in which the effects of diffusion, chloride binding and convection due to water movement can be taken into account. The aim of this research was to reach a better understanding on the physical mechanisms underlying the deterioration process of reinforced concrete associated with chloride-induced corrosion and to propose a reliable method for estimating these effects. Chloride concentrations coming from de-icing salts are significantly influenced by the exposure conditions such as salt usage, ambient temperature and repeated wet-dry cycles.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.1269-1271
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• 2008

We find some array mura are caused by S/D bridge or channel open in 4 mask process. The gray tone PR thickness non-uniformity is the main reason of these defects. By the adjustment of exposure and dry etch parameters, S/D bridge and channel open ratio drops by 10.87%.