• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1092-1095
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• 2005

The effect of the dielectric constant (${\varepsilon}$) of bonding materials in screen-printed carbon nanotube cathode on field enhancement factor was investigated using the ANSYS software for high-efficient CNT-cathodes. The field enhancement factor increased with decreasing the dielectric constant and reaching a maximum value when the dielectric constant is 1, the value for a vacuum. This indicates that the best bonding materials for screen-printing CNT cathodes should have a low dielectric constant and this can be used as criteria for selecting bonding materials for use in CNT pastes for high-efficient CNT-cathodes

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.132-137
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• 2000

A complete theoretical treatment of the photothermal displacement technique has been performed for thermal diffusivity measurement in solid materials. The influence of parameters - radius and modulation frequency of pump beam and thickness of material - on the phase lag was studied. The phase decreases up to a certain position, then starts to increase and does have an asymptotic value. The position, where phase has the minimum value, is a function of thermal diffusion length thickness of sample, and radius of pump beam. A new method based on minimum phase lag is described to determine the thermal diffusivity of solid material.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1994년도 추계학술대회 논문집
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• pp.139-142
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• 1994

Ceramic filter using energy trapping pheonomenon is used bandpass filter at high frequency. In this paper, we analyzed theoretically ceramic filter characteristics of TS vibrational mode and also investigated experimentally it. The ceramic plate is PZT-4 poled in the thickness direction of Valpey Fisher Co. and electroded with two pairs. We analyzed the characteristics in appling to the all constant of ceramic and electrode material each other and vibrational mode. We also measured resonant frequency and bandpass width of the ceramic filter changing the thickness of ceramic plate and electrode spacing. Comparing of falter characteristics, theoretical value nearly corresponded with experimental value. So we saw that we can expect filter characteristics changing the thickness of ceramic plate and electrode spacing.

• 대한전기학회논문지
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• 제40권12호
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• pp.1242-1251
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• 1991

This paper is to investigate the tree growth phenomena and the characteristics of $\varepsilon$' and tan$\delta$ for the effect of ultrasonic wave on polymer insulation material. The conclusions are as follows. 1) As the pressure amplitude of ultrasonic wave is larger and its irradiated time is longer, tree inception voltage and its breakdown voltage in specimen are smaller, and tree growing is faster. 2) As the irradiated quantity of ultrasonic wave is more increased, the value of tan$\delta$ is larger, but the value of $\varepsilon$' is almost constant. 3) The effect by the pressure amplitude of ultrasonic wave is greater than that by its irradiated time on the insulation characteristics of polymer material.

• 환경영향평가
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• 제19권1호
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• pp.49-57
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• 2010

The objective of the research is to analyze changing trend of water discharge in precipitation, according to changing land use, through an environment-friendly urban development method called LID. The study chose S1 basin (Separated Sewer districts) in Cheongju region for survey. Among LID methods, relatively more applicable methods of green rooftop space and parking lot with permeable material were selected to construct plausible scenarios. Curve Number (CN) value was calculated due to land use patterns in each scenario, and SWMM model simulation were conducted during 2008 for comparative analysis. For Case 1, only parking lot with permeable material was applied to the scenario. Green rooftop space I and II were applied to Case 2 and 3 respectively. For Case 4 and 5, green rooftop space I and II were applied, in addition to parking lot with permeable material, Calculation of CN value showed that for S1 basin, the value was 88.1 (prior to scenario application), 86.5 (Case 1), 81.9 (Case 2), 68.5 (Case 3), 80.4 (Case 4) and 67.2 (Case 5). Changing pattern of rain water discharge was analyzed for each scenario. For Case 1, the change was not remarkable before and after application of scenario. In Case 2 and 4, the impact of rain water discharge as source of pollutant fell to 20~30%. The rate dropped to 30~50% in Case 3 and 5 respectively. The result demonstrates that the amount of rain water discharge, amount and frequency of sewer overflow, frequency of rain water discharge, and pollution load decreased in accordance with declining CN value in each scenario. In installing green rooftop space, the effect was twice greater when rain water discharge was directly infiltrated into soil.

• 한국건설관리학회논문집
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• 제3권4호
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• pp.114-122
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• 2002

EVMS(Earned Value Management System)는 최근 건설 프로젝트를 관리하는데 매우 유용한 도구로 인식되고 있으며, 정부차원에서 적극적으로 도입을 검토하고 있는 선진 관리기법이다. 이 EVMS는 미국방성에 의해 1960년대부터 프로젝트의 효율적인 관리를 위해 개발된 C/SCSC(Cost/schedule Control System Criteria)에 기반을 두고 있으며, 국내외에서 정부발주공사뿐만 아니라 민간발주의 건설프로젝트를 관리하는 도구로 활용하기 위해 연구가 활발하게 진행되고 있다. 본 연구에서는 공정관리 프로그램과 복합작업모델(Work Package Model)을 바탕으로 건설프로젝트의 EV계획단계의 관리계정계획(CAP)을 수립하는데 효과적으로 사용할 수 있는 방안을 제조업의 재고관리모형중의 한 형태로 조립제품의 자원운영계획을 수립하는데 우수한 기법으로 알려진 MRP(Material Requirement Planning)기법을 활용하여 제시하고자 한다.

• 한국건설관리학회논문집
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• 제4권1호
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• pp.90-96
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• 2003

도심지 건축공사가 증가하고 있는 우리나라에서 작업공간의 부족 및 자재의 적시공급에 대한 문제는 반드시 해결해야 할 과제이다. 이 중에서도 주택건설에 있어 가장 큰 비중을 차지하고 있는 아파트 시공의 경우, 초고층화로 골조공사의 중요성과 함께 친환경적 공법과 합리적 공정개선 및 원가절감을 구현할 새로운 공법이 요구되고 있다. 본 연구에서는 국내 건설현장의 사례조사를 통해 슬래브 거푸집공사와 마감공사의 프로세스에서 불필요한 요소를 최소화하고자 공업화 자재를 활용한 (골조-마감공사)통합공법을 제시한다 가치흐름분석기법(Value Stream Mapping)을 활용하여 기존 프로세스에서의 비 가치 창출작업을 가치창출작업에 통합시키거나 제거하여 슬래브 공사 내에서 공기 및 투입인력의 절감 가능성을 확인하고, 공기단축과 원가절감 효과를 측정하였다. 이와 같이 공업화 자재의 활용으로 현장작업에 따른 변이를 최소화하여 공정의 안정성 및 공정계획의 신뢰성을 확보 등 공정의 합리화를 구현하고자 한다.

• Tribology and Lubricants
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• 제19권1호
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• pp.1-8
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• 2003

Recently, PM-high speed steel(PM-HSS) has reportedly been a good alternative material for rolling mill because of its superior performance to conventional HSS. This paper has been aimed to investigate the possibility for application to rolling contact element for PM-HSS by X-ray diffraction technique. The X-ray elastic constant for PH-HSS has been found by X-ray diffraction during the four-point bending test. Residual stress and half-value breadth on the contact surface during rolling contact fatigue process by X-ray diffraction have also been measured. The result of this study shows that the application of X-ray diffraction technique to PM-HSS could be as possible alternative material as conventional HSS. Half-value breadth on rolling contact surface by X-ray diffraction is not changed during rolling contact fatigue process. On the other hand, the residual stress is changed. This suggests that dislocation reaction has been hardly occurred in rolling contact, depending on super-saturated carbon in PM-HSS.

• 한국전기전자재료학회논문지
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• 제14권6호
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• pp.511-517
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• 2001

We evaluated the electrical properties of 37 multifilamentary jointed tapes processed by superconducting joint. In the superconducting joining method, a lap-joint was used. Tapes were selectively etched, and exposed superconducting cores of the two tapes were brought into contact with each other and then only the joined region was uniaxially pressed in the range of 1,000 to 2,50 MPa. The critical current ratio(CCR) and n-value of the jointed tape were evaluated as a function of uniaxial pressure and number of step in the contacting region. It was observed that the CCR was dependent on the number of step, but almost independent of uniaxial pressure. The highest critical current ratio and n-value were obtained to be 58% and 26%, respectively, for the jointed tape to the tape itself.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.135-135
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• 2009

In this work we compared the electrical characteristic of single gate and dual gate in MIC-TFT. We fabricated p-channel TFTs based on MIC structure. In mobility, dual gate ($61.35cm^2/Vsec$) got a higher value than single gate ($55.96cm^2/Vsec$). In $I_{on}/I_{off}$ dual gate ($6.94{\times}10^6$) got a higher value than single gate ($1.72{\times}10^6$) too. In $I_{off}$, dual gate got a lower value than single gate. Therefore, dual gate is good and less power consumption than single gate.