• 접착 및 계면
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• 제11권4호
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• pp.168-173
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• 2010

할로겐 함유 난연 화합물은 인체에 무해하고 유해가스 발생이 없는 환경 친화적인 소재로 대체되어가고 있다. 반도체 소자의 밀봉용 소재로 사용되는 에폭시 수지 조성물도 친환경적인 소재로 만들기 위해서, 에폭시 수지의 자소화에 관해 많은 연구가 이루어지고 있다. 본 연구에서도 신규 에폭시 수지(E3)를 사용하여 할로겐계 화합물을 전혀 함유하지 않는 자소성 에폭시 수지 조성물을 제조하였다. 새로 만들어진 에폭시 수지 조성물(EMC-1)은 UL 난연 V0를 갖고 5 wt% 분해 온도가 $451.9^{\circ}C$로, 할로겐계 난연제나 삼산화안티몬 등을 첨가하지 않고도 난연성이 우수하고 열분해성, 내열성 등이 우수하게 나타나 친환경 소재로 적용할 수 있다.

• 한국전기전자재료학회논문지
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• 제16권8호
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• pp.700-704
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• 2003

This paper describes on characteristics of 2" 3C-SiC wafer bonding using PECVD (plasma enhanced chemical vapor deposition) oxide and HF (hydrofluoride acid) for SiCOI (SiC-on-Insulator) structures and MEMS (micro-electro-mechanical system) applications. In this work, insulator layers were formed on a heteroepitaxial 3C-SiC film grown on a Si (001) wafer by thermal wet oxidation and PECVD process, successively. The pre-bonding of two polished PECVD oxide layers made the surface activation in HF and bonded under applied pressure. The bonding characteristics were evaluated by the effect of HF concentration used in the surface treatment on the roughness of the oxide and pre-bonding strength. Hydrophilic character of the oxidized 3C-SiC film surface was investigated by ATR-FTIR (attenuated total reflection Fourier transformed infrared spectroscopy). The root-mean-square suface roughness of the oxidized SiC layers was measured by AFM (atomic force microscope). The strength of the bond was measured by tensile strength meter. The bonded interface was also analyzed by IR camera and SEM (scanning electron microscope), and there are no bubbles or cavities in the bonding interface. The bonding strength initially increases with increasing HF concentration and reaches the maximum value at 2.0 ％ and then decreases. These results indicate that the 3C-SiC wafer direct bonding technique will offers significant advantages in the harsh MEMS applications.ions.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.15-18
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• 2003

Ta-Ti metal alloy is proposed for alternate gate electrode of ULSI MOS device. Ta-Ti alloy was deposited directly on $SiO_2$ by a co-sputtering method and good interface property was obtained. The sputtering power of each metal target was 100W. Thermal and chemical stability of the electrode was studied by annealing at $500^{\circ}C$ and $600^{\circ}C$ in Ar ambient. X-ray diffraction was measured to study interface reaction and EDX(energy dispersive X-ray) measurement was performed to investigate composition of Ta and Ti element. Electrical properties were evaluated on MOS capacitor, which indicated that the work function of Ta-Ti metal alloy was ${\sim}4.1eV$ compatible with NMOS devices. The measured sheet resistance of alloy was lower than that of poly silicon.

• 한국전기전자재료학회논문지
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• 제34권1호
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• pp.73-77
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• 2021

Inorganic-organic hybrid perovskite solar cells have demonstrated considerable improvements, reaching 25.5% of certified power conversion efficiency in 2020 from 3.8% in 2009. In normal structured perovskite solar cells, TiO2 electron-transporting materials require heat treatment process at a high temperature over 450℃ to induce crystallinity. Inverted perovskite solar cells have also been studied to exclude the additional thermal process by using [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) as a non-oxide electron-transporting layer. However, the drawback of the PCBM layer is a charge accumulation at the interface between PCBM and a metal electrode. The impact of bathocuproin (BCP) buffer layer on photovoltaic performance has been investigated herein to solve the problem of PCBM. 2-mM BCP-modified perovskite solar cells were observed to exhibit a maximum efficiency of 12.03% compared with BCP-free counterparts (5.82%) due to the suppression of the charge accumulation at the PCBM-Au interface and the resulting reduction of the charge recombination between perovskite and the PCBM layer.

• 콘크리트학회논문집
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• 제17권6호
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• pp.885-892
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• 2005

콘크리트 구조물을 보수 또는 보강하기 위해서 폴리머 콘크리트 혹은 폴리머 시멘트 모르타르를 종종 사용한다. 보수된 콘크리트 구조물의 일교차 또는 열악한 환경에 의한 온도강하 시 두 재료의 상이한 열팽창계수와 보수 재료의 초기양생 시 나타나는 건조수축으로 인해 계면에 응력이 발생하게 된다. 이러한 추가적으로 발생하는 응력은 계면의 부착력을 저하시켜 때로는 구조물에 큰 손상을 유발할 수 있다 본 연구에서는 이러한 문제를 해결하고자 단면보수 및 증대를 위해 사용되는 보수 모르타르에 섬유앵커를 추가로 적용함으로서, 부착력 저하를 감소시키는지 여부를 실험을 통하여 검토하였다. 또한 보수 단면에 적용하는 앵커가 계면 전단응력에 미치는 영향을 유한요소해석을 통하여 검토를 시도하였다.

• 열처리공학회지
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• 제34권2호
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• pp.66-74
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• 2021

Cladding material, which can selectively obtain excellent properties of different metals, is a composite material that combines two or more types of dissimilar metals into one plate. The titanium-copper cladding material between titanium which has excellent corrosion resistance and copper which has high thermal and electrical conductivity, are highly valuable composite materials. It can be used as heat exchangers with high conductivity under severe corrosion conditions. In order to apply the clad plate to the heat exchanger, it must be manufactured in the form of a tube and additional welding is required. It is important to select the cladding material manufacturing process and the welding process. The process of manufacturing the cladding material includes extrusion, rolling, and explosive bonding. Among them, the explosive bonding process is suitable for additional welding because no heat-affected zone is formed. In this study TIG welding of the explosive-bonded dissimilar clad plates was successfully performed by butt welding. The microstructures and bonding interface of the welded part were observed, and the effect of the bonding layer at the welding interface and the intermetallic compounds on the mechanical properties and tensile plastic deformation behaviors were analyzed. And also the integrity of TIG-welded dissimilar part was evaluated.

• International journal of advanced smart convergence
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• 제2권2호
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• pp.19-22
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• 2013

As the demand of the LED for lighting that emits light by p-n junction is increasing, studies on heatproof plate technology is being conducted to minimize the temperature of the LED lighting. As for the temperature of the LED devices, their light emitting efficiency decreases and the maximum lifespan drops down to 1/5. Therefore there are heat dissipation studies going on to minimize the heat. For LED heat dissipation, aluminum heat sink plates are mostly used. For this paper, we designed heat sink that fits residential 20W COB LED Down Light; packaged the heat sink and 20W COB and analyzed and evaluated the thermal properties through a Solidworks flow simulation. We are planning to design the optimal heat sink plate to solve the thermal agglomeration considering TIM(Thermal Interface material).

• 공업화학
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• 제8권4호
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• pp.667-672
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• 1997

고용량 Nickel/Metal hybride 전지의 온도 거동을 3차원 유한요소법 software인 NISA를 사용하여 해석하였다. 전지 내부의 열전도에는 미분형 에너지 수지식을, 외부 대기와의 접촉면은 대류 열전달 방식을 사용하였다. 전지 온도에 영향을 미치는 요소인 열발생량과 대류 열전달계수에 대한 실험을 행하였고, 이 결과로부터 일반식을 도출하였다. 금속 재질의 cooling fin을 사용하므로써 급속한 충전이나 방전시 야기될 수 있는 온도 상승을 상당 부분 방지할 수 있었다. 전지 외벽에 열전도도가 낮고 얇은 절연물질을 부착하여도 최고온도의 상승에 미치는 영향은 미미하였다.

• 한국자동차공학회논문집
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• 제11권6호
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• pp.93-100
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• 2003

This paper describes the thermoelastic instability arising from friction heat generation in braking and proposes the finite element methods to predict the variation of temperature and thermal deformation. In a conventional disc brake analysis, heat generation is only related with wheel speed and friction material and the interface pressure between disc and pad is assumed constant. But under dynamic braking conditions, the frictional heat causes the thermoelastic distortion that leads to more concentrated contact pressure distribution and hence more and more non-uniform temperature. In this paper, to complete the solution of the thermomechanically coupled problem, the linear relation model between pressure and temperature is proposed and demonstrated in examples of a simple two dimensional contact problem. And the two dimensional model has been extended to an annular three dimensional disc model in order to consider more realistic geometry and to provide a more accurate critical speed for automotive brake systems.

• Structural Engineering and Mechanics
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• 제46권6호
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• pp.827-842
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• 2013

In this paper, the wave propagation in generalized thermo elastic plate immersed in fluid is studied based on the Lord-Shulman (LS) and Green-Lindsay (GL) generalized two dimensional theory of thermo elasticity. Two displacement potential functions are introduced to uncouple the equations of motion. The frequency equations that include the interaction between the plate and fluid are obtained by the perfect-slip boundary conditions using the Bessel function solutions. The numerical calculations are carried out for the material Zinc and the computed non-dimensional frequency, phase velocity and attenuation coefficient are plotted as the dispersion curves for the plate with thermally insulated and isothermal boundaries. The wave characteristics are found to be more stable and realistic in the presence of thermal relaxation times and the fluid interaction.