• Journal of the Korean Recycled Construction Resources Institute
• /
• v.8 no.1
• /
• pp.25-32
• /
• 2013

This study has been conducted in order to propose Eco-friendly and High functional waterproofing technology available for structure by verifying application and performance of water proofing material(s) in purpose of making effective use of reclaimed rubber. As s result of 12 months evaluation, stable performance for water pressure and lateral pressure of $0.3N/mm^2$ were confirmed. Also, as the time elapsed, the amount of water absorption and adhesion performance showed only a slight difference(+0.05g, $-0.1Nmm^2$) as well, which in turn confirmed that waterproofing performance remains stable. Studies show that it is expected to expand recycling technology of natural rubber by applying reclaimed rubber on construction waterproofing field, and to hold a technical superiority by using eco-friendly material in construction waterproofing market throughout active application of these types of research.

• Korean journal of applied entomology
• /
• v.54 no.4
• /
• pp.289-294
• /
• 2015

Striped flea beetle, Phyllotreta striolata (SFB) and turnip sawfly, Athalia rosae ruficornis (TSF) are two economically important sporadic pests in radish fields on Jeju island. The response of adult SFB and TSF to a mixture of aggregation pheromone, (+)-(6R,7S)-himachala-9,11-diene and host plant volatile, allyl isothiocyanate (HAI), as well as to yellow and blue sticky traps was examined in radish fields. Adult SFB was more attracted to the sticky trap with HAI, regardless of the color of the sticky trap; however, adult TSF was more attracted on the yellow sticky trap than blue, and no effect of HAI was observed. The adult SFB and TSF can be effectively monitored using yellow sticky traps placed 10 cm above the plant canopy. SFB and TSF had 3 and 5 peak times in a year, respectively. The first peak occurred in the middle of March for SFB and mid-late of April for TSF. We expect that the results of the present study can facilitate minimizing the damage caused by the two important pests in commercial radish fields.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.11a
• /
• pp.168-169
• /
• 2009

본 연구에서는 ITO 표면 개질에 의한 유기 발광 소자의 특성 변화에 대해서 연구하였다. ITO 전극은 발광 소자의 투명 전극으로 널리 사용되고 있으며 이러한 발광 소자의 특성은 ITO의 표면 상태에 따라 민감하게 반응한다. ITO 표면 개질은 ITO와 유기물 사이의 쇼트기 장벽을 감소시키며, 전극과 유기물의 점착을 향상시켜 준다. 본 실험에서는 습식 처리 방식으로 self-assembled monolayer(SAM)을 사용하였다. 유기 발광 소자의 특성은 SAM 처리에 의해 향상 되었다. 유기 발광 소자는 ITO/SAM/TPD(50nm)/$Alq_3$(70nm)/LiF(0.5nm)/Al(100nm)의 구조로 제작하였으며, ITO의 표면 특성은 일반적인 특성 기술에 의해 연구되었다. SAM 처리된 소자는 SAM 처리하지 않은 소자에 비해 구동 전압, 발광 세기, 외부 양자 효율 등이 향상되었다. ITO의 SAM 처리 시간을 0/10/15/20/25분으로 하여 소자를 제작하였다. 15분간 SAM 처리한 소자는 SAM 처리하지 않은 소자에 비해 외부 양자 효율과 전류 효율이 2.6배 상승하였다. 본 실험을 통하여 ITO 표면 위에 SAM층을 삽입한 걸과, 구동 전압, 발광 세기, 효율 등이 향상됨을 알 수 있었다.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.3
• /
• pp.547-554
• /
• 2008

In this paper, two-stage pipelined floating-point multiplier (FP-MUL) is designed. The FP-MUL processor supports single precision multiplication for 3D graphic APIs, such as OpenGL and Direct3D and has area-efficient and low-latency architecture via saturated arithmetic, area-efficient sticky-bit generator, and flagged prefix adder. The FP-MUL has about 4-ns delay time under $0.13{\mu}m$ CMOS standard cell library and consists of about 7,500 gates. Because its maximum performance is about 250 MFLOPS, it can be applicable to mobile 3D graphics application.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.25 no.12
• /
• pp.1721-1729
• /
• 2001

The performance of gas turbines is decreased as their operating hours increase. Fouling in the axial compressor is one of main reasons for the performance degradation of gas turbine. Airborne particles entering with air at the inlet into compressor adhere to the blade surface and result in the change of the blade shape, which is closely and sensitively related to the compressor performance. It is difficult to exactly analyze the mechanism of the compressor fouling because the growing process of the fouling is very slow and the dimension of the fouled depth on the blade surface is very small compared with blade dimensions. In this study, an improved analytic method to predict the motion of particles in compressor cascades and their deposition onto blade is proposed. Simulations using proposed method and their comparison with field data demonstrate the feasibility of the model. It if found that some important parameters such as chord length, solidity and number of stages, which represent the characteristics of compressor geometry, are closely related to the fouling phenomena. And, the particle sloe and patterns of their distributions are also Important factors to predict the fouling phenomena in the axial compressor of the gas turbine.

• 유체기계공업학회:학술대회논문집
• /
• 2000.12a
• /
• pp.176-183
• /
• 2000

The performance of gas turbines decreases as their operating hours increase. Compressor fouling is the main reason for this time-dependent performance degradation. Airborne particles adhere to the blade surface and results in the change in the blade shape. It is difficult to exactly analyze the mechanism of the compressor fouling because the growing process of the fouling is very slow and the dimension of the fouled depth is very small compared with blade dimensions. In this study, an analytic method to predict the motion of particles and their deposition inside axial flow compressors is proposed. The analytic model takes into account the blade shape and the flow within the blade passage. Comparison of simulation result with field data shows the feasibility of the model. Influence of the particle distribution on the compressor fouling is also examined.

• Proceedings of the KIEE Conference
• /
• 2015.07a
• /
• pp.1607-1608
• /
• 2015

현대사회의 고속 고급 교통수단에 대한 요구에 부응하고, 고유가 및 온실가스 등 원유 기반의 교통 시스템의 문제를 해결하기 위해 교통 수단의 다양화 연구가 활발히 진행되고 있다. 석유문제가 심각한 상황으로 전개될 경우, 대륙과 대륙 그리고 국가와 국가 사이의 장거리 이동을 할 수 있는 교통수단은 전기로 추진되는 철도이다. 현재 대중화 되어있는 바퀴 식 철도차량은 초고속 운전 시 기하급수적으로 증가하는 소음, 공기저항 동력 전달의 한계, 레일의 마모라는 문제를 가지고 있으며 이러한 문제점을 가진 철도차량의 대안으로 선형 추진 시스템 연구가 진행 중이다[1] 국내에서는 LSM(Linear Synchronous motor)에 대한 연구가 활발히 진행되고 있으나 LPM 기반 철도 차량 추진시스템에 대한 연구는 이루어지지 않고 있다. 그러나 LSM 추진 시스템에 비하여 LPM 추진 시스템은 우수한 등판 능력, 광역범위의 주행 가능 영역, 경량화에 따른 높은 에너지 효율, 건설비 저감등 다양한 장점을 가지고 있으며 충분한 전략성을 가지고 있다.

• Journal of the Korean Geotechnical Society
• /
• v.29 no.11
• /
• pp.17-27
• /
• 2013

This study is to prove the efficiency of geo-synthetics on the crushed stone layer by experiments. The strength of PET mat as reinforcing soft ground was verified through the loading experiments. Also, PP mat was used to protect the blockage of crushed stone layer by the filled soil, whose efficiency was examined according to loading and infiltration conditions. The crushed stones were penetrated into clay layer if the PET mat was removed, which was verified by loading experiments. In addition, the cohesioness of soil without PP mat made the blockage of stone layer easily, which reduced the infiltration capacity by about 98%.

• Clean Technology
• /
• v.29 no.3
• /
• pp.193-199
• /
• 2023

Biomass has been used to secure renewable energy certificates (REC) in domestic and overseas coal-fired power plants. In recent years, biofuel has been diversified from traditional wood pellets to non-woody biomass. Non-woody biomass has a higher content of alkaline metals such as K and Na than wood-based biomass, resulting in a lower melting point and an increase in slagging on boiler tubes, which reduces boiler efficiency. This study analyzed the effect of kaolin, an additive commonly used to increase melting points, on biomass co-firing to coal through thermochemical equilibrium calculations. In a previous experiment on biomass co-firing to coal conducted at 80 kW_th, it was interpreted that the use of kaolin actually increased the amount of fouling. In this study, analysis showed that when kaolin was added, aluminosilicate compounds were generated due to Al₂O₃, which is abundant in coal, and mullite was formed. Thus, it was confirmed that the amount of slag increased when more kaolin was used. Further analysis was conducted by increasing the biomass co-firing rate from 0% to 100% at 10% intervals, and the results showed non-linear liquid slag generation. As a result, it was found that the least amount of liquid slag was generated when the biomass co-firing rate was between 50 and 60%. The phase diagram analysis showed that high melting point compounds such as leucite and feldspar were most abundantly generated under these conditions.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.166.1-166.1
• /
• 2016

각종 부품의 내마모성 및 내식성을 개선하기 위해서 금속물질에 나노두께의 보호막층을 입혀 경도를 높이는 표면처리 기술이 개발되고 있다. TiN막은 기계적 경도, 내마모성 및 내식성이 우수하여 수없이 연구되어 왔으며 박막의 두께에 따라 다양한 색상표현이 가능하다는 연구도 진행되고 있다. 이러한 TiN 박막의 연구결과로 높은 경도와 강도를 요하는 절삭공구에 하드 코팅을 이용하여 높은 절삭력으로 고효율적인 작업환경을 조성할 수 있다. 기존에 연구되어 온 TiN박막은 Ar과 N2의 혼합가스 분위기에서 증착된 반면 본 실험에서는 영구자석을 이용한 고밀도 플라즈마로 높은 점착성과 균일한 박막 및 대면적 공정이 가능한 RF-magnetron sputtering방법을 이용하여 N2 분위기에서 TiN박막을 $100^{\circ}C{\sim}400^{\circ}C$의 온도범위에서 $100^{\circ}C$간격으로 열처리 후 증착하여 비교실험을 하였다. 이와 같이 제작된 TiN박막을 XRD(X-ray Diffraction)를 사용하여 결정성을 확인한 결과 온도가 높을수록 (111)방향의 결정성장이 뚜렷하게 나타났으며 그 외 Scratch Test와 HM-220(Micro-vicker's tester)를 사용하여 경도특성을 확인하고 SEM(Scanning Electron Microscope), AFM(Atomic Force Microscope)를 이용하여 박막의 표면형상을 측정하였다. 이러한 측정 결과로 향후에는 높은 내마모성 및 초경도가 요구되는 절삭공구 및 경질표면코팅이 필요한 금속산업분야에 적용이 가능 할 것이라 사료된다.