• 한국식품저장유통학회지
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• 제4권2호
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• pp.101-113
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• 1997

Temperature, relative humidity and ventilation are closely related one another, and they are the main factors to be controlled for the environmental control system of a storage facility. Conventional environmental control systems do not consider the interrelationship between temperature, relative humidity and ventilation, which results in low performance and high energy consumption. To overcome the inefficiency of the conventional ones, it was developed an on-off control system based on the interrelationship between the factors. The usefulness of the system was illustrated with the results produced by a set of experiments in a real world.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.1.1-1.1
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• 2011

Printed electronics based on the direct writing of solution processable functional materials have been of paramount interest and importance. In this talk, the synthesis of printable inorganic functional materials (conductors and semiconductors) for thin-film transistors (TFTs) and photovoltaic devices, device fabrication based on a printing technique, and specific characteristics of devices are presented. For printable conductor materials, Ag ink is designed to achieve the long-term dispersion stability and good adhesion property on a glass substrate, and Cu ink is sophisticatedly formulated to endow the oxidation stability in air and even aqueous solvent system. The both inks were successfully printed onto either polymer or glass substrate, exhibiting the superior conductivity comparable to that of bulk one. In addition, the organic thin-film transistor based on the printed metal source/drain electrode exhibits the electrical performance comparable to that of a transistor based on a vacuum deposited Au electrode. For printable amorphous oxide semiconductors (AOSs), I introduce the noble ways to resolve the critical problems, a high processing temperature above $400^{\circ}C$ and low mobility of AOSs annealed at a low temperature below $400^{\circ}C$. The dependency of TFT performances on the chemical structure of AOSs is compared and contrasted to clarify which factor should be considered to realize the low temperature annealed, high performance AOSs. For photovoltaic application, CI(G)S nanoparticle ink for solution processable high performance solar cells is presented. By overcoming the critical drawbacks of conventional solution processed CI(G)S absorber layers, the device quality dense CI(G)S layer is obtained, affording 7.3% efficiency CI(G)S photovoltaic device.

• 전기전자학회논문지
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• 제18권1호
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• pp.152-158
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• 2014

본 연구에서는 저온유동성 성능검사 시스템 구현을 통해 디젤 차량용 통합형 연료히터의 성능을 평가한다. 저온 유동성 시험장치에서 $+20{\sim}-30^{\circ}C$ 온도범위에 따라 분리형과 통합형 연료히터 성능을 비교하고, 필터 전후에 따라 유압과 시동시간, 히터의 소모전력을 측정한다. 이때 다양한 종류의 필터면적을 사용함으로써 통합형 연료히터와 분리형을 비교한 결과 시동 시간이 23% 향상되었고, 저온시동성능은 19% 정도 향상된다.

• 한국세라믹학회지
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• 제47권1호
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• pp.75-81
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• 2010

The feasibility of using the thin film technology in utilizing lanthanum strontium manganite (LSM) for a solid oxide fuel cell (SOFC) cathode in a low-temperature regime is investigated in this study. Thin film LSM cathodes were fabricated using pulsed laser deposition (PLD) on anode-supported SOFCs with yttria-stabilized zirconia (YSZ) electrolytes. Although cells with a 1 ${\mu}m$-thick LSM cathode showed poor low-temperature cell performance compared to that of a cell with a bulk-processed cathode due to the lack of a triple-phase boundary length, the cell with 200 nm-thick gadolinia-doped ceria (GDC) inserted between the LSM and YSZ showed enhanced performance and more stable operation characteristics in a comparison of a cell without a GDC layer. We postulate that the GDC layer likely improved the cathode adhesion, therefore contributing to the improvement of the cell performance instead of serving as an interfacial reaction buffer.

• 설비공학논문집
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• 제28권10호
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• pp.387-393
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• 2016

A ground source heat pump system maintains a constant efficiency due to its stable heat source and radiant heat temperature which provide a more effective thermal performance than that of the air source heat pump system. As an eco-friendly renewable energy source, it can reduce electric power and carbon dioxide. In this study, we analyzed one year of data from a web based remote monitoring system to estimate the thermal performance of GSHP with the capacity of 3RT, which is installed in a low energy house located in Daejeon, Korea. This GSHP system is a hybrid system connected to a solar hot water system. Cold and hot water stored in a buffer tank is supplied to six ceiling cassette type fan coil units and a floor panel heating system installed in each room. The results are as follows. First, the GSHP system was operated for ten minutes intermittently in summer in order to decrease the heat load caused by super-insulation. Second, the energy consumption in winter where the system was operated throughout the entire day was 7.5 times higher than that in summer. Moreover, the annual COP of the heating and cooling system was 4.1 in summer and 4.2 in winter, showing little difference. Third, the outlet temperature of the ground heat exchanger in winter decreased from $13^{\circ}C$ in November to $9^{\circ}C$ in February, while that in summer increased from $14^{\circ}C$ to $17^{\circ}C$ showing that the temperature change in winter is greater than that in summer.

• 한국재료학회지
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• 제27권3호
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• pp.149-154
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• 2017

Transparent conducting oxides (TCOs) were fabricated using solution-based ITO (Sn-doped $In_2O_3$) nanoinks with nanorods at an annealing temperature of $200^{\circ}C$. In order to optimize their transparent conducting performance, ITO nanoinks were composed of ITO nanoparticles alone and the weight ratios of the nanorods to nanoparticles in the ITO nanoinks were adjusted to 0.1, 0.2, and 0.5. As a result, compared to the other TCOs, the ITO TCOs formed by the ITO nanoinks with weight ratio of 0.1 were found to exhibit outstanding transparent conducting performance in terms of sheet resistance (${\sim}102.3{\Omega}/square$) and optical transmittance (~80.2 %) at 550 nm; these excellent properties are due to the enhanced Hall mobility induced by the interconnection of the composite nanorods with the (440) planes of the short lattice distance in the TCOs, in which the presence of the nanorods can serve as a conducting pathway for electrons. Therefore, this resulting material can be proposed as a potential candidate for solution-based TCOs for use in optoelectronic devices requiring large-scale and low-cost processes.

• Korean Chemical Engineering Research
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• 제57권1호
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• pp.22-27
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• 2019

매니큐어는 손톱을 아름답게 꾸미기 위해 사용하는 색조화장품이지만 그 구성성분은 유해성분이 상당히 포함되어 있다. 매니큐어는 일반적으로 피막형성제, 색소, 용제, 계면활성제 및 침전방지제 등으로 구성되어 있다. 본 연구에서는 유해성 성분을 저자극, 친환경적인 성분으로 대체하여 4종의 매니큐어를 제조하고, 매니큐어로서 효력 비교실험과 안전성 및 안정성 시험을 실시하였다. 효력비교실험에서 쉘락/젤라틴 매니큐어 조성물(No. 4)이 내수성 및 적당한 강도를 지니면서 건조시간이 2분 내외로 대조군(4분 내외)보다 우수하고 악취도 개선되어, 피막형성제로서 가장 우수한 특성을 보여주었다. 또한 쉘락/젤라틴 매니큐어 조성물의 세포독성시험 결과, $1,000{\mu}g/mL$ 농도에서 70% 이상의 세포생존율로 시판되고 있는 매니큐어(50% 세포생존율)보다 독성이 낮았다. 4주간 온도 안정성 시험에서 저온에서는 색상의 변화가 없었으나, 상온과 고온에서 외관상변화 및 점도변화가 관찰되어 추후 제형의 개선이 필요한 것으로 생각된다.

• Computers and Concrete
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• 제33권5호
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• pp.605-619
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• 2024

The increase of reclaimed asphalt pavement (RAP) content in recycled asphalt concrete (RAC) is accompanied by the degradation of low-temperature cracking resistance, which has become an obstacle to the development of RAC. This paper aims to reveal the meso-scale mechanisms of the low-temperature fracture behavior of RAC and provide a theoretical basis for the economical recycling of RAP. For this purpose, micromechanical heterogeneous peridynamic model of RAC was established and validated by comparing three-point bending (TPB) test results against corresponding numerical simulation results of RAC with 50% RAP content. Furthermore, the models with different aggregate shapes (i.e., average aggregates circularity (${\bar{C_r}}=1.00$, 0.75, and 0.50) and RAP content (i.e., 0%, 15%, 30%, 50%, 75%, and 100%) were constructed to investigate the effect of aggregate shape and RAP content on the low-temperature cracking resistance. The results show that peridynamic models can accurately simulate the low-temperature fracture behavior of RAC, with only 2.9% and 13.9% differences from the TPB test in flexural strength and failure strain, respectively. On the meso-scale, the damage in the RAC is mainly controlled by horizontal tensile stress and the stress concentration appears in the interface transition zone (ITZ). Aggregate shape has a significant effect on the low-temperature fracture resistance, i.e., higher aggregate circularity leads to better low-temperature performance. The large number of microcracks generated during the damage evolution process for the peridynamic model with circular aggregates contributes to slowing down the fracture, whereas the severe stress concentration at the corners leads to the fracture of the aggregates with low circularity under lower stress levels. The effect of RAP content below 30% or above 50% is not significant, but a substantial reduction (16.9% in flexural strength and 16.4% in failure strain) is observed between the RAP content of 30% and 50%. This reduction is mainly attributed to the fact that the damage in the ITZ region transfers significantly to the aggregates, especially the RAP aggregates, when the RAP content ranges from 30% to 50%.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.165-170
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• 2012

This study aims to analyze the characteristics of temperature variation of Spandrels. According to the change of SHGC of Window system, air space, insulation performance and absorption factor of inner surface at the Spandrels, It was firstly estimated by using simulation. Secondly, measured to minimize the temperature-rise of inner surface temperature and the intermediate air temperature by using Full-scale Mock-up based on the result of simulation analysis. As a result, it turns out that low SHGC window system such as BIPV system had an advantage of reducing the window surface temperature, and the surface temperature of clear window system was all higher than BIPV system on simulation results. In the experiment results, it had some advantages of increasing the Spandrels volume, decreasing insulation performance and lower absorption factor.

• 한국산학기술학회논문지
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• 제14권2호
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• pp.681-687
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• 2013

본 연구는 학습 환경의 실내 온도와 학습재료 색채와의 조합이 학습수행에 어떠한 영향을 미치는 지를 살펴보고자 하였다. 이를 위해 학습활동 적정온도($22.5{\sim}24^{\circ}C$)를 중심으로(중립 실내 온도 조건), 그 이상인 조건(고온 실내온도 조건), 그리고 그 이하인 조건(저온 실내 온도 조건)으로 각각 실내 온도 조건을 구분하였으며, 난색계열인 빨간색과 한색계열인 파란색, 그리고 중성인 검은색과 연두색으로 각각 색채 조건을 구분하였다. 학습과 관련된 과제로는 음운 작업기억 과제를 사용하여 집단 간 실내 온도 조건에 따른 색채 조건에서의 과제 수행을 살펴보았다. 그 결과, 학습과제의 반응시간에서는 각 독립변수들에 의한 차이가 유의하지 않은 반면, 정확률에서는 색채 조건 중 빨간색과 검은색 조건에서 보다 정확한 수행이 나타났다. 이는 빨간색이 가진 현저성과 색채 온도감 및 검정색이 가진 친숙성과 다른 색에 비해 유일하게 현저성을 가지지 않는 특이성이 존재하기 때문에 나타난 결과로 해석할 수 있다.