• 대한기계학회논문집A
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• 제25권7호
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• pp.1082-1088
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• 2001

Nowadays study on recycling disused plastics for automobiles was lively progressed. Rubber and talcum powder was added to retrieve degradation of physical properties caused by recycling disused polypropylene. The effect of the temperature, the fatigue load and the loading speed on DEN(double edged notch) specimen which was made by the pp-rubber composites during fracture was studied by. DEN specimen was made on PP-rubber composites through the injection molding. With increasing temperature the fracture strength was linearly decreased and the fracture energy was increased by $0^{\circ}C$ and after that decreased. In the same temperature the fracture strength during increasing the notch radius was hardly increased. The fracture behaviour at low and high loading speed was different entirely. At high loading speed plastic region was small and fracture behaviour was seen to brittle fracture tendency. With increasing fatigue load fracture energy was first rapidly decreased and subsequently steady when radius of notch tip was 2mm, but Maximum load during fracture scarcely varied. The deformation mechanism of polypropylene-rubber composites during fracture was studied by SEM fractography. A strong plastic deformation of the matrix ahead of the notch/crack occurred. The deformation seem to be enhanced by a thermal blunting of the notch/crack.

• 한국전산유체공학회지
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• 제18권4호
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• pp.25-34
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• 2013

A numerical study of a laminar natural convection of the CuO-water nanofluid in a square cavity using the Buongiorno's nonhomogeneous model is presented. All the governing equations including the volume fraction equation are discretized on a cell-centered, non-uniform grid employing the finite-volume method with a primitive variable formulation. Calculations are performed over a range of Rayleigh numbers and volume fractions of the nanopartile. From the computed results, it is shown that both the homogeneous and nonhomogeneous models predict the deterioration of the natural convection heat transfer well with an increase of the volume fraction of nanoparticle at the same Rayleigh number, which was observed in the previous experimental studies. It is also shown that the differences in the computed results of the average Nusselt number at the wall between the homogeneous and nonhomogeneous models are very small, and this indicates that the slip mechanism of the Brown diffusion and thermophoresis effects are negligible in the laminar natural convection of the nanofluid. The degradation of the heat transfer with an increase of the volume fraction of the nanoparticle in the natural convection of nanofluid is due to the increase of the viscosity and the decrease of the thermal expansion coefficient and the specific heat. It is clarified in the present study that the previous controversies between the numerical and experimental studies are owing to the different definitions of the Nusselt number.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.178-178
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• 2010

With the scaling down of ULSI(Ultra Large Scale Integration) circuit of CMOS(Complementary Metal Oxide Semiconductor)based electronic devices, the electronic devices become more faster and smaller size that are promising field of semiconductor market. However, very narrow line width has some disadvantages. For example, because of narrow line width, deposition of conformal and thin barrier is difficult. Besides, proportion of barrier width is large, thus resistance is high. Conventional PVD(Physical Vapor Deposition) thin films are not able to gain a good quality and conformal layer. Hence, in order to get over these side effects, deposition of thin layer used of ALD(Atomic Layer Deposition) is important factor. Furthermore, it is essential that copper atomic diffusion into dielectric layer such as silicon oxide and hafnium oxide. If copper line is not surrounded by diffusion barrier, it cause the leakage current and devices degradation. There are some possible methods for improving the these secondary effects. In this study, TaNx, is used of Tertiarybutylimido tris (ethylamethlamino) tantalum (TBITEMAT), was deposited on the 24nm sized trench silicon oxide/silicon bi-layer substrate with good step coverage and high quality film using plasma enhanced atomic layer deposition (PEALD). And then copper was deposited on TaNx barrier using same deposition method. The thickness of TaNx was 4~5 nm. TaNx film was deposited the condition of under $300^{\circ}C$ and copper deposition temperature was under $120^{\circ}C$, and feeding time of TaNx and copper were 5 seconds and 5 seconds, relatively. Purge time of TaNx and copper films were 10 seconds and 6 seconds, relatively. XRD, TEM, AFM, I-V measurement(for testing leakage current and stability) were used to analyze this work. With this work, thin barrier layer(4~5nm) with deposited PEALD has good step coverage and good thermal stability. So the barrier properties of PEALD TaNx film are desirable for copper interconnection.

• 폴리머
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• 제24권6호
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• pp.829-836
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• 2000

SMC 욕조 생산 시 발생하는 폐 FRP와 석재 가공공정에서 발생되는 석분슬러지를 재활용하기 위하여 불포화에스테르 매트릭스 수지에 분말 충전하여 복합재를 제조하였다. 또한 충전제와 매트릭스 간의 계면결합력을 향상시키기 위해 석분을 실란 커플링제 ${\gamma}$-methacryloxypropyltrimethoxysiiane (${\gamma}$-MPS)로 전처리하여 복합재를 제조하고 기계적 물성 및 계면현상을 관찰하였다. 복합재의 굴곡탄성율은 석분함량이 10 wt%, 실란커플링제의 농도가 3 wt%일 때 가장 우수하였으며 석분 충전량이 증가함에 따라 감소하는 경향을 보였다. 또한 복합재의 초기 열분해온도는 352~359$^{\circ}C$이었으며 이 온도에서 중량감소율은 약 3%로 충전제의 양에 관계없이 거의 일정한 경향을 보였다. ${\gamma}$-MPS 처리에 따른 복합재의 물성변화를 관찰한 결과 충전제와 매트릭스 수지간 계면결합력이 증진되어 물리 화학적으로 안정한 결합을 이루고 있고 pull out현상이 발생하지 않음을 확인할 수 있었다.

• 폴리머
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• 제38권2호
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• pp.240-249
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• 2014

다중벽 탄소나노튜브(MWNT)로 보강된 폴리에스터(PET) 복합재료에 관한 연구를 수행하였다. PET와 MWNT간의 계면결합력을 향상시키기 위하여, MWNT 표면에 bishydroxyethylene-terephthalate(BHET)를 도입하였다. 이렇게 기능화된 MWNT를 0.5~2.0 wt% 범위에서 이축압출기를 이용하여 PET와 용융 혼합하였다. MWNT/PET 복합재료를 필라멘트로 방사하고, 이를 연신 및 열처리하여 특성 분석을 하였다. 이로부터 복합섬유의 결정화 온도와 열분해 온도가 MWNT로 인하여 증가함을 알 수 있었으며, 항복응력과 인성은 MWNT의 1 wt%의 첨가만으로도 30%이상 증가함을 알 수 있었다. 따라서 MWNT를 BHET로 기능화하는 방법은 폴리에스터에 탄소나노튜브를 효과적으로 분산시키고 계면결합력을 증가시키는데 매우 효과적임을 알 수 있었다.

• 한국재료학회지
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• 제9권5호
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• pp.503-508
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• 1999

We have investigated the physical and diffusion barrier property of Ti-Si-N film for Cu metallization. The ternary compound was deposited by using reactive rf magnetron sputtering of a TiSi$_2$target in an Ar/$N_2$gas mixture. Resistivities of the films were in range of 358$\mu$$\Omega$-cm, to 307941$\mu$$\Omega$-cm, and tended to increase with increasing the $N_2$/Ar flow rate ratio. The crystallization of the Ti-Si-N compound started to occur at 100$0^{\circ}C$ with the phases of TiN and Si$_3$N$_4$identified by using XRD(X-ray Diffractometer). The degree of the crystallization was influenced by the $N_2$/Ar flow ratio. The diffusion barrier property of Ti-Si-N film for Cu metallization was determined by AES, XRD and etch pit by secco etching, revealing the failure temperature of 90$0^{\circ}C$ in 43~45at% of nitrogen content. In addition, the very thin compound (10nm) with 43~45at% nitrogen content remained stable up to $700^{\circ}C$. Furthermore, thermal treatment in vacuum at $600^{\circ}C$ improved the barrier property of the Ti-Si-N film deposited at the $N_2$(Ar+$N_2$) ratio of 0.05. The addition of Ti interlayer between Ti-Si-N films caused the drastic decrease of the resistivity with slight degradation of diffusion barrier properties of the compound.

• 한국전기전자재료학회논문지
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• 제18권1호
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• pp.62-67
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• 2005

Recently, polymer insulators that are used for high voltage applications have some advantages such as light weight, small size, vandalism resistance, hydrophobicity and easy making process. During outdoor service of polymer insulators, the surface of the insulating material is frequently subjected to moisture and contamination that lead to dry band arcing. Their tracking resistance, erosion resistance, end sealing and shed design are very important because dry band arcing causes degradation of polymer surface. Aging test to estimate life property of polymer insulator is executed through several international standard such as IEC 61109 and CEA tracking wheel test, but is not getting clear conclusion yet. There are two methods in the diagnosis method of polymer insulator such as off-line and on-line. The diagnosis methods in off-line are external condition analysis by the eye, contaminant analysis on surface, surface analysis, pollution withstand voltage test, power frequency flashover voltage test, lightning impulse flashover test, tensile fracture load test and flexural load test. Polymer material is also investigated it's tracking resistance by adding surface active agent in IEC 587. In this paper, the tracking performance of polymer insulator with salt solution which is added surface active agent. The diagnosis of insulator sample has been analyzed by leakage current and visual examination, STRI guide and thermal image camera.

• 한국해양환경ㆍ에너지학회지
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• 제15권1호
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• pp.19-21
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• 2012

내연 기관의 엔진오일은 열화작용에 의해서 수명이 짧아지고 대기오염을 유발하게 된다. 엔진오일의 상태를 정확히 측정하여 새오일로 교환함으로 엔진의 수명 연장 및 환경오염을 줄일 수 있다. 정전용량 프로브는 엔진오일과 같은 유체의 유전율을 측정하는데 사용 할 수 있다. 본 논문은 엔진 오일의 열화 정도에 따라서 달라지는 유전율 특성을 분석하였다. 오일의 상태에 따라서 달라지는 프로브의 정전용량을 각각 LCR Meter로 측정하여 엔진오일의 유전율을 계산하였다. 또한, 프로브의 크기에 따른 정전용량의 변화를 측정하여 유전율 측정의 정확도를 제시한다. 오염된 오일 일수록 유전율이 증가하며, 유전율로 오일의 오염정도를 판단하는 것이 가능하다.

• 한국식품과학회지
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• 제40권6호
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• pp.611-620
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• 2008

달걀 노른자에 함유된 인지질 중 PC와 PE를 추출, 분리하고 이를 토코페롤을 제거한 TSCO에 0, 200, 500, 2,000 ppm의 농도로 단독으로, 또는 1,000 ppm씩 혼합하여 첨가한 후 $180^{\circ}C$에서 12시간 동안 가열하여 함유된 인지질의 함량변화와 TSCO의 갈색화 정도를 살펴보고, TSCO의 가열산화에 미치는 영향을 지방산 조성, 공액이중산값, 아니시딘값으로 평가하였다. TSCO에 첨가된 인지질은 가열 시작 후 2-3시간 내에 매우 빠르게 소실되었고, 가열 중 PE의 분해속도가 PC에 비해 높았다. PC와 PE가함께 첨가된 TSCO를 가열할때 PE는 PC의 분해를 억제하였다. TSCO는 가열 시간이 증가함에 따라 갈색화가 증가하였고, PC와 PE는 갈색화를 촉진하였으며 PE가 PC보다 큰 영향을 주었다. 가열 중 TSCO의 P/L, P/Ln, 공액이중산값, 아니시딘값은 증가하였으며, PC의 첨가는 이들 값을 낮추어 가열 카놀라유의 산화방지제 역할을 하였으나 PE는 큰 영향을 나타내지 않았으며, PC와 PE는 TSCO의 가열산화 억제에 있어서 antagonism이 관찰되었다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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• pp.95.1-95.1
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• 2012

Very High Temperature gas cooler Reactor (VHTR) has been considered as one of the most promising nuclear reactor because of many advantages including high inherent safety to avoid environmental pollution, high thermal efficiency and the role of secondary energy source. The TRISO coated fuel particles used in VHTR are composed of 4 layers as OPyC, SiC, IPyC and buffer PyC. The significance of CVD-SiC coatings used in tri-isotropic(TRISO) nuclear coated fuel particles is to maintain the strength of the whole particle. Various methods have been proposed to evaluate the mechanical properties of CVD-SiC film at room temperature. However, few works have been attempted to characterize properties of CVD-SiC film at high temperature. In this study, micro tensile system was newly developed for mechanical characterization of SiC thin film at elevated temperature. Two kinds of CVD-SiC films were prepared for micro tensile test. SiC-A had [111]-preferred orientation, while SiC-B had [220]-preferred orientation. The free silicon was co-deposited in SiC-B coating layer. The fracture strength of two different CVD-SiC films was characterized up to $1000^{\circ}C$.The strength of SiC-B film decreased with temperature. This result can be explained by free silicon, observed in SiC-B along the columnar boundaries by TEM. The presence of free silicon causes strength degradation. Also, larger Weibull-modulus was measured. The new method can be used for thin film material at high temperature.