• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1220-1223
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• 2009

The effect of silver (Ag) nano-particles on OLEDs was investigated by using a finite difference time domain (FDTD) tool. The proposed OLEDs employed Ag nanoparticles thermally deposited in a high vacuum on a cathode. The emission rate of the exciton was improved by 1.8 fold compared to the conventional OLEDs without Ag nano-particles. Less spacing between the dipole source and the Ag nano-particles resulted in a larger emission rate of the exciton in the OLED with nano-particles. The size of the Ag nano-particles was proportional to the emission rate of the exciton in a range of nano-meter scale of nano-particles. The enhancement of the emission rate of the exciton due to Ag nano-particles caused the improvement in the efficiency of the proposed OLED.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(2)
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• pp.330-333
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• 2000

With the recent development of the ultrahigh-speed optical time division multiplexed system, high-repetition rate optical-pulse stream generation is necessary. This is different from conventional approaches, which use fiber or integrated waveguide delay line circuits. The high-repetition-rate optical-pulse multiplication phenomenon occurs when the optical pulse's spectral width is greater than the transfer bandwidth of the coupler used. From the analysis, the output repetition rate can be controlled by using fiber couplers with different equivalent transfer bandwidths. The pulse seperation spacing is controlled by number of cascaded coupler in optical loop mirror coupler scheme.

• Earthquakes and Structures
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• 제24권3호
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• pp.183-192
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• 2023

It is essential to properly understand the seismic behavior of reinforced concrete (RC) columns confined by stirrups that experience different corrosion rates. The current study investigated the effect of seismic performance indicators such as strength loss, energy dissipation rate, ductility and hysteresis damping on specimens and models for different stirrup corrosion rates. Analysis revealed the adverse effects of corrosion on the bond performance between the concrete and steel bars which affected the seismic performance of the columns. It was found that with increasing corrosion rate, ductility and energy dissipation of the specimens decreased. Compared with the uncorroded specimen, the ductility factor and energy dissipation decreased observably, by 22.89% and 60.64%, respectively. An attenuation relationship is proposed for the corrosion rate of the stirrups for different stirrup yield strengths, concrete compressive strengths, concrete covers and stirrup spacing.

• 한국지반공학회논문집
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• 제29권4호
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• pp.13-22
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• 2013

본 연구에서는 스미어가 발생한 지반을 모사하고 배수재 간격비에 따른 스미어 영역 겹침 유 무가 차후의 압밀거동에 미치는 영향을 분석하기 위해 대형압밀챔버와 맨드렐 관입시험기를 이용하여 다양한 실내모형실험을 수행하였다. 또한, 이를 바탕으로 유한요소해석을 실시하였고 연직배수공법의 효율성을 분석하였다. 실험 및 해석결과 스미어 발생은 침하량을 증가시키지만 스미어 겹침은 반대로 침하량을 감소시키는 경향을 보였다. 또한 연직배수재를 설치하면 압밀이 촉진되지만 배수재 간격을 줄여도 스미어의 영향으로 압밀속도는 크게 빨라지지 않았으며, 오히려 스미어 영역이 겹칠 정도로 배수재 간격을 줄이면 압밀효율이 급격히 떨어지는 것으로 나타났다.

• 한국재료학회지
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• 제19권1호
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• pp.1-6
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• 2009

In this study, the stress-strain response and the cracking behaviors of ITO film on a PET substrate are investigated. The cracking behaviors of ITO thin films deposited on a thermoplastic semi-crystalline polymer developed for flexible display applications was investigated by means of tensile experiments equipped with an electrical measurement apparatus and an in-situ optical microscope. Electrical resistance increased gradually in the elastic-to-plastic transition region of the stress strain curves and cracks formed. Numerous cracks were found in this region, and the increase of the resistance was linked to the cracking of ITO thin films. Upon loading, the initial cracks perpendicular to the tensile axis were observed at about 1% of the total strain. They propagated to the entire sample width as the strain increased. The spacing between the horizontal cracks is thought to be determined by the fracture strength and the thickness of the ITO film as well as by the interfacial strength between the ITO and PET. The effect of the strain rate on the cracking behavior was also investigated. The crack density increased as the strain increased. The spacing between the horizontal cracks (perpendicular to the stress axis) increased as the strain rate decreased. The increase of the crack density as the strain rate decreased can be attributed to the higher fraction of the plastic strain to the total strain at a given total strain. The higher critical strain for the onset of the increase in the resistance and the crack initiation of the ITO/PET with a thinner ITO film (300 ohms/sq.) suggests a higher strength of the thinner ITO film.

• 한국수자원학회논문집
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• 제37권3호
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• pp.219-231
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• 2004

수중폭기장치로 저수지 성층을 파괴시켜 저수지 수질을 개선시키기 위한 방법이 최근 널리 이용되고 있다. 본 연구는 주요 성층 파괴기작인 Bubble Plume(공기 부력류)의 수리동역학적 거동특성과 플륨 간격에 따라 변하는 모멘텀 중첩효과가 성층파괴 효율에 어떠한 영향을 미치는지에 대하여 수행하였다. 이를 위해 전산유체(CFD) 소프트웨어를 이용한 2상(공기-물) 3차원의 탈성층모델을 개발했으며, 이로부터 계절에 따라 변하는 다양한 성층강도와 주입 공기량에 따라 변하는 비정상상태의 성층파괴 발달과정은 물론 최적 탈성층 효율을 갖는 플륨간격을 제안할 수 있었다. 모델검증을 위한 실험을 위해 대형 실험조를 개발했으며, 온도성층은 소금물을 이용했던 기존연구와는 달리 가열순환수를 이용한 자연성층을 재현시켜 수행하였다. 연구결과 탈성층 효율은 디퓨서 배치간격에 크게 영향을 받는 것으로 밝혀졌으며, 플륨간격이 수심의 약 1.5배 이내익 때 중첩영향이 강하게 일어났고, PN가 클수록 간격에 영향을 상대적으로 크게 받았다. 또한, 간격이 수심보다 작곤 때는 효율이 PN에 비례해서 선형적으로 증가한 반면 그 이상에서는 효율이 상대적으로 감소하면서 비선형적으로 증가하는 현상을 밝혀냈다. 이상의 연구결과를 통해 주입공기량은 PN가 약 1000, 디퓨서 배치간격은 수심의 1.5배일 때가 최적의 성층파괴 조건인 것으로 나타났다.

• 한국작물학회지
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• 제63권4호
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• pp.378-383
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• 2018

본 연구는 건강 기능성 팥에 대한 소비자의 선호도가 높아지면서 수요와 재배면적이 점차 확대되고 있는 팥의 생산량 증대와 자급률 향상을 위한 체계적인 재배기술을 확립하기 위한 기초자료를 얻고자 기계화 수확에 적합한 넓은이랑 줄뿌림 재배시 재식밀도에 따른 생육 및 수량에 관한 연구를 수행하였다. 1. 경장은 주간거리가 짧아질수록 '아라리' 품종은 길어지는 경향을 보였으나, '홍언' 품종에서는 대체적으로 짧아지는 경향으로 나타났으며, 경태와 분지수에서는 두 품종 모두 주간거리가 짧아질수록 가늘어지거나 적어지는 경향이 나타났다. 2. 착협고는 재식거리가 짧을수록 높아지는 경향이 나타났으며 '홍언'에서는 $30{\times}10cm$ 처리구에서 5.0 cm로, '아라리'에서는 $30{\times}10cm$과 $50{\times}10cm$ 처리구에서 8.8 cm로 가장 높았다. 3. 주당협수와 주당립수는는 두 품종 모두 재식거리가 길어질수록 많아지는 경향이 나타났으며, 백립중에서는 '홍언'에서는 재식밀도간의 차이가 나타났으나, '아라리' 에서는 재식밀도간 차이는 나타나지 않았다. 4. 수량성은 조간거리 40cm${\times}$주간거리 15 cm 처리구에서 두 품종 모두 (285, $374kg{\cdot}10a^{-1}$) 가장 높았다.

• 한국주조공학회지
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• 제21권6호
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• pp.343-349
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• 2001

The effect of cooling rate on the solidification microstructure and segregation behavior of 7075 and 7050 aluminum alloy was investigated. Samples were solidified with cooling rates from 0.3 to $17^{\circ}K/sec$. Using the cooling curves of each sample, liquidus, eutectic and intermetallic reaction temperatures were estimated. The microstructures were characterized in terms of dendrite arm spacing and eutectic volume fraction. The segregation behavior of each alloying element of these alloys in various cooling rates was discussed.

• International Journal of Industrial Entomology and Biomaterials
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• 제7권1호
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• pp.45-49
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• 2003

Foliar treatment with different concentrations of potassium chloride (KCl) to mulberry plants resulted in higher level of total chlorophyll, total sugars, soluble protein, in vivo nitrate reductase activity (NRA), net photosynthetic rate (NPR), pWUE and leaf yield. Optimal concentration was found to be 10.0 mM KCl with limited irrigation provided in the mulberry plantation planted in 90 ${times}$ 90 cm spacing. The deleterious effect of soil moisture stress condition has been found to be overcome by KCl foliar spray twice at 15 days interval. Regression and correlation coefficients were analyzed, and a strong positive correlation was found between chlorophyll and total sugars, soluble protein and in vivo nitrate reductase activity, leaf dry weight and net photosynthetic rate and pWUE and net photosynthetic rate.

• 한국분무공학회지
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• 제7권4호
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• pp.9-15
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• 2002

Convolution Fourier transformation tomographically reconstructs the spatially resolved spray injection rate from direct measuring cells. Asymmetric sprays generated from a twin-hole air shroud injector are tested with 12 equiangular projections of measurements. For each projection angle, line of sight integrated injection rate was measured at 35 positions with equal spacing measuring cells of 3 mm in width, 100 mm in length, 55 mm in depth and 0.5 mm thickness of separating wall. Interpolated data between the projection angles effectively increase the number of projections, which significantly enhances the signal-to-noise level in the reconstructed data. This modified convolution Fourier transformation scheme predicts well the structure of asymmetric sprays. Comparative study has been made between sprays with and without air shrouding. Tomograhpic reconstruction of injection rate from direct measuring cells obtained can be used to estimate the accuracy of volume fraction of spray from the LDPA tomographic reconstruction.