• 청정기술
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• 제30권1호
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• pp.13-22
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• 2024

본 연구에서는 6,13-Bis(triisopropylsilylethynyl)pentacene(TP):2-Decyl-7-phenyl[1]benzothieno[3,2-b][1]benzothiophene(BT):Poly styrene (PS) 블랜딩 thin film transistor (TFT)를 제작 광 흡수 센서로의 활용에 대해 탐구한다. BT의 혼합으로 인해 off current 감소와 on/off ratio 향상을 동시에 달성하였다. 특히, TP:BT:PS (1:0.25:1 w/w) 샘플은 우수한 광 흡수 특성을 보여주었고, 이를 통해 높은 성능의 광 흡수 장치 제작이 가능함을 입증했다. 다양한 혼합 비율의 결정 구조와 전기적 특성에 대한 분석을 통해 TP:BT:PS (1:0.25:1 w/w) 샘플이 최적임을 확인하였다. 이 결과는 광 흡수 장치의 발전 뿐만 아니라 혼합 organic semiconductor (OSC)의 광전자 시스템 개발에 긍정적인 기대효과를 미칠 수 있을 것이며, 이를 통해 단일 OSC 사용의 제약을 극복하고, 미세 조정된 광학 응답을 갖춘 고성능 OSC TFT를 제작하여 의료 전자소자, 산업용 전자소자 등에 응용할 수 있을 것으로 기대된다.

• 아시안잔디학회지
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• 제25권1호
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• pp.106-111
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• 2011

본 연구는 아메리카동애등애 사육과정에서 발생한 분변토(SFC)가 골프장의 토양개량제로서 사용가능성을 평가하기 위해 모래와 혼합비율별 물리화학성을 조사하고자 한다. 토양개량제의 혼합비율에 따라 상토의 물리화학성을 조사한 결과는 다음과 같다. SFC, compost 및 cocopeat는 pH와 EC에서 고도의 정의 상관성 (P<0.01)을 나타내어 토양개량제의 특성에 따라 상토의 토양화학성에 영향을 주었다. SFC와 compost의 혼합에 따른 토양물리성 변화에서 가장 중요한 요인은 모세관공극으로 총공극이나 수리전도도의 변화에 영향을 미쳤다. 토양개량제의 혼합비율에 따른 토양개선효과를 비교할 때, SFC는 모세관공극, 총공극 및 수리전도도에서, compost는 모세관공극, 비모세관공극, 총공극 및 수리전도도에서, cocopeat는 모세관공극과 비모세관공극에서 고도의 상판성을 나타내었다(P<0.05). 이들 결과를 통해 토양개량제의 종류와 특성 및 혼합비율이 USGA 상토의 근권층 개량과 토양 이화학성에 영향을 미치고 있음을 알 수 있으며, 본 실험조건에서는 SFC는 상토의 공극과 수리전도도의 개선효과를 보였다.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.380-385
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• 2004

The efficiency of complex slurry preparation route for developing the high performance SiC matrix of RS-SiCf/SiC composites has been investigated. The green bodies for RS-SiC materials prior to the infiltration of nw/ten silicon were prepared with various C/SiC complex matrix slurries, which associated with both different sizes of starting SiC particles and blending ratios of starting SiC and carbon particles. The characterization of RS-SiC materials was examined by means of SEM, TEM, EDS and three point bending test. Based on the mechanical property-microstructure correlation, process optimization methodology is also discussed. The flexural strength of RS-SiC materials greatly depended on the content of residual Si. The decrease of starting SiC particle size in the C/SiC complex slurry was effective for improving the flexural strength of RS-SiC materials.

• Geomechanics and Engineering
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• 제14권6호
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• pp.533-544
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• 2018

The importance of using materials cost effectively to enhance the strength and reduce the cost, and weight of earth fill materials in geotechnical engineering led researchers to seek for modifying the soil properties by adding proper additives. Lightweight fill materials made of soil, binder, water, and Expanded polystyrene (EPS) beads are increasingly being used in geotechnical practices. This paper primarily investigates the behavior of sandy soil, modified by EPS particles. Besides, the mechanical properties of blending sand, EPS and the binder material such as fly ash and cement were examined in different mixing ratios using a number of various laboratory studies including the Modified Standard Proctor (MSP) test, the Unconfined Compressive Strength (UCS) test, the California Bearing Ratio (CBR) test and the Direct Shear test (DST). According to the results, an increase of 0.1% of EPS results in a reduction of the density of the mixture for 10%, as well as making the mixture more ductile rather than brittle. Moreover, the compressive strength, CBR value and shear strength parameters of the mixture decreases by an increase of the EPS beads, a trend on the contrary to the increase of cement and fly ash content.

• 동력기계공학회지
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• 제13권6호
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• pp.29-34
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• 2009

Recently, we have a lot interest in a sudden rise of oil prices and a change weather for the earth warmming, so, development of new alternative fuels need in order to spare fossil fuel and reduce exhaust emissions for air pollution prevention. Biodiesel, which can be generated from natural renewable sources such as new or used vegetable oils or animal fats, may be used as fuel in diesel engine of compression ignition engine. In this paper, the combustion characteristics between neat diesel oil and biodiesel blends(10 vol.% biodiesel and 20 vol.% biodiesel) were tested using four stroke, direct injection diesel engine, especially this biodiesel was produced from soybean oil at our laboratory. This analysis showed that cylinder pressures, the rate of pressure rises and the rate of heat releases were decreased as the blending ratios of biodiesel to diesel oil increased because of lower heating value of biodiesel in spite of increased oxygen content in biodiesel.

• Fibers and Polymers
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• 제3권1호
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• pp.38-42
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• 2002

Polypropylene filaments were spun from a mixture of PP chips of two different Melt Flow Index (MFI) (3 MFI and 35 MFI). A significant difference was observed in the melting characteristics of the resultant filaments from either of the individual components as observed from the DSC. The main difference being in the degree of melting achieved at any temperature in the initial stages of the melting range, which was found to be higher in case of the filaments spun from the b]end. These filaments were then thermally bonded using silicon oil bath and heated roller method. Subsequently the bond strength of the filaments was measured on the Instron Tensile Tester using the loop technique. The values of the world strengths obtained from the blend were compared with those made from the individual component. It was found that the bond strength of the bonds obtained from the blended filament at a given temperature was higher than that of the bonds made from the filaments of either of the individual components, which is also suggested by the DSC curves. The difference in the bond strength was found to be as high as 25% in case of the blend with 60:40 composition ratios of the 3 MFI and 35 MFI components respectively.

• Journal of Biosystems Engineering
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• 제35권4호
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• pp.239-243
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• 2010

Biodiesel (BD) can be effectively used as an alternative fuel in diesel engines. However, BD may affect the performance and exhaust emissions in diesel engines because it has different physical and chemical properties from diesel fuel such as viscosity, compressibility and so on. To investigate the effect of injection timing on the characteristics of engine performance and exhaust emissions with BD in an indirect injection diesel engine, BD derived from soybean oil was applied in this study. The engine was operated at six different injection timings from TDC to BTDC $12^{\circ}CA$ and five loads at various engine speeds. Below BD 30, there's similar trend compared with diesel fuel. But, the best injection timing was $4{\sim}6^{\circ}CA$ retarded compare with diesel fuel using BD 30. When the fuel injection timing was retarded, better results were showed, which may confirm by advantages of BD.

• 멤브레인
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• 제11권1호
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• pp.22-28
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• 2001

이온성 고분자에 비이온성 고분자를 섞어 이온 함량을 조절함으로써 다양한 전하량을 갖는 이온성 막을 제조하였다. 비이온성 고분자로는 폴리비닐알콜, 음이온성 고분자로는 알긴산 나트륨, 양이온성 고분자로는 키토산을 사용하였으며, 이들 이온성 고분자막을 사용하여 여러 전해질 수용액에 대한 투과 및 분리특성을 관찰하였다. 막 내부에 이온성 고분자 함량이 많을수록 친수성 특성을 보였으며, 순수투과 및 용액투과 속도가 증가함을 관찰할 수 있었고, 또한 투과속도는 막의 팽윤 거동에 의해 결정됨을 확인할 수 있었다. 용질 배제율의 경우는 막과 투과용질간의 정전기적 인력, 즉 Donnan exclusion에 의해 결정이 되며, 정전기적 인력이 비슷한 경우는 분자체 효과에 의해 분리됨이 관찰되었다.

• Journal of Advanced Marine Engineering and Technology
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• 제32권1호
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• pp.27-32
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• 2008

Recently, we have a lot of interest in alternative fuels to provide energy independence from oil producing country and to reduce exhaust emissions for air pollution prevention. Biodiesel, which can be generated from natural renewable sources such as new or used vegetable oils or animal fats, may be used as fuel in diesel engine of compression ignition engine. In this paper, the test results on specific fuel consumption and exhaust emissions of neat diesel oil and biodiesel blends(10 vol.% biodiesel and 20 vol.% biodiesel) were presented using four stroke, direct injection diesel engine, especially this biodisel was produced from soybean oil at our laboratory. This study showed that Soot and CO emission were decreased as the blending ratios of biodiesel to diesel oil increased, on the other hand NOx emission was slightly increased because of the oxygen content in biodiesel. Also, the biodiesel blends yielded slightly higher specific fuel consumption than that of diesel oil because of lower heating value of biodiesel.

• 폴리머
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• 제27권5호
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• pp.405-412
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• 2003

수용성 고분자인 폴리(비닐 알코올) (PVA)과 키토산에 제 4급 암모늄염을 도입하여 합성한 수용성 키토산 유도체인 N-(2-하이드록시)프로필-3-트리메틸 키토산 클로라이드 (HTCC)를 수용액 상태로 하여 용액 블렌딩하고 이를 캐스팅하여 PVA/HTCC 블렌드 필름을 제조한 후 두 고분자 사이의 혼화성과 블렌드 필름의 특성을 FT-IR, DSC, DMA 및 TGA를 사용하여 검토하였다. HTCC 함량을 50%까지 변화시킨 본 연구의 혼합 범위에서 블렌드 필름들은 모두 투명한 상태를 나타내었으며, T$_{g}$와 T$_{m}$ 이 하나로 나타나 두 고분자 사이에 혼화성이 있음을 확인하였다. 또, HTCC의 우수한 항미생물성 때문에 HTCC가 1%만 포함되더라도 블렌드 필름은 우수한 항미생물성을 나타내었다.