• 접착 및 계면
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• 제20권2호
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• pp.71-75
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• 2019

탄닌산은 식물계에서 가장 많이 발견되는 폴리페놀 중 하나로, 초기 탄닌산 연구는 항산화제 등과 같은 생리학적 기능에 집중되어 있었다. 그러나 최근에는 탄닌산이 단백질, DNA 등 거의 모든 생체고분자와 분자간결합을 하는 것이 밝혀짐에 따라 분자적 접착제로서 많은 관심을 받고 있다. 탄닌산의 다양한 특성들은 표면의 기능, 젖음성을 조절할 뿐 아니라 에너지 저장 및 발생 장치에 기여하고, 의학적 제재로의 다양한 가능성을 보이고 있다. 본 논문에서는 분자적 접착제로서의 탄닌산과 생체고분자와의 결합, 탄닌산을 통한 표면 개질, 의료용 제재로의 활용 등에 대해 다루고자 한다.

• 한국표면공학회지
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• 제54권5호
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• pp.207-212
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• 2021

The mechanical and electrical characteristics can be improved in 3D stacked IC technology which can accomplish the ultra-high integration by stacking more semiconductor chips within the limited package area through the Cu direct bonding method minimizing the performance degradation to the bonding surface to the inorganic compound or the oxide film etc. The surface was treated in a ultrasonic washer using a diamond abrasive to remove other component substances from the prepared cast plate substrate surface. FE-SEM was used to analyze the bonding characteristics of the bonded copper substrates, and the cross section of the bonded Cu conjugates at the sintering junction temperature of 100 ℃, 150 ℃, 200 ℃, 350 ℃ and the pressure of 2303 N/cm² and 3087 N/cm². At 2303 N/cm², the good bonding of copper substrate was confirmed at 350 ℃, and at the increased pressure of 3087 N/cm², the bonding condition of Cu was confirmed at low temperature junction temperature of 200 ℃. However, the recrystallization of Cu particles was observed due to increased pressure of 3087 N/cm² and diffusion of Cu atoms at high temperature of 350 ℃, which can lead to degradation in semiconductor manufacturing.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기물성,응용부문
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• pp.215-219
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• 2004

Metal-chelate derivatives have been investigated intensively as an emitting layer and recognize to have excellent electroluminescence(EL) properties. We synthesized new luminescent material, 1,4-dihydoxy-5,8-naphtaquinone $Aiq_3$ complex($Al_2Nq_4$) and investigated the electrical optical properties. OLED has potential candidates for information display with merits of thickness, low power and high efficiency. Although the OLED show a lot of advantages for information display, it has the limit of inorganic(metal)/ organic interface. In this study, the two methods are used to study the interface of metal/organic in OLED. First, we treated $O_2$ plasma on an ITO thin film by using RIE system, and analyzed the ingredient of ITO thin film according to change of the processing conditions. We used the RDS and the XPS for the ingredient analysis of the surface and bulk. We measured electrical resistivity using Four-Point-Probe and calculated sheet resistance, and ITO surface roughness was measured by using AFM. We fabricated OLED using substrate that was treated optimum ITO surface. Second, we used the buffer layer of CuPc to improve the characteristics of the interface and the hole injection in OLED. The result of the study for electrical and optical properties by using I V L T System(Flat Panel Display Analysis System), we confirmed that the electrical properties and the luminance properties were improved.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.270-270
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• 2013

We have investigated the self-assembled structures of glutaric acid (HOOC-(CH2)3-COOH) on the Cu(110) surface as a function of coverage using Scanning Tunneling Microscopy (STM). At low coverage, glutaric acid molecules diffuse freely on Cu(110) surface at room temperature, thus they can't form ordered structures at this coverage. However, when we scanned the same area several times, novel structures have been created during scanning due to the field-induced self-assembly. Also, the induced structures are quite stable during continuous scanning process. At 0.25 ML, glutaric acid adsorbs as a bi-glutarate (-OOC(CH2)3-COO-) after annealing to 450 K producing a racemic conglomerate of coexisting mirror domains. Although the molecule is achiral, it forms chiral domains on the surface from adsorption-induced asymmetrization. At 0.5 ML coverage, zigzag structure is observed, and still gltutaric acid adsorbs as a bidentate configuration. This bi-glutarate structure is stable until 650. Finally, at 1ML, glutaric acid adsorbs as a mono-glutarate at room temperature forming close packed structures.

• Geomechanics and Engineering
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• 제23권1호
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• pp.39-50
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• 2020

In order to understand the shear mechanical properties of the interface between clay and structure and better serve the practical engineering projects, it is critical to conduct shear tests on the clay-structure interface. In this work, the direct shear test of clay-concrete slab with different joint roughness coefficient (JRC) of the interface and different normal stress is performed in the laboratory. Our experimental results show that (1) shear strength of the interface between clay and structure is greatly affected by the change of normal stress under the same condition of JRC and shear stress of the interface gradually increases with increasing normal stress; (2) there is a critical value JRC_cr in the roughness coefficient of the interface; (3) the relationship between shear strength and normal stress can be described by the Mohr Coulomb failure criterion, and the cohesion and friction angle of the interface under different roughness conditions can be calculated accordingly. We find that there also exists a critical value JRC_cr for cohesion and the cohesion of the interface increases first and then decreases as JRC increases. Moreover, the friction angle of the interface fluctuates with the change of JRC and it is always smaller than the internal friction angle of clay used in this experiment; (4) the failure type of the interface of the clay-concrete slab is type I sliding failure and does not change with varying JRC when the normal stress is small enough. When the normal stress increases to a certain extent, the failure type of the interface will gradually change from shear failure to type II sliding failure with the increment of JRC.

• Tribology and Lubricants
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• 제30권5호
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• pp.247-255
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• 2014

Charged polymer chains, i.e., polyelectrolytes, are known to show superior aqueous lubricating properties compared to those of neutral polymer chains, especially in brush conformation. This is primarily because of the incorporation of a large amount of counterions within the polymer layers and the consequently increased osmotic pressure. However, this effect is active only when the polymer chains remain immobilized even under tribostress, which is not realistic for high-contact pressure tribological applications, especially when they are irreversibly immobilized on tribopair surfaces. In contrast, with free polymers, which can be included as surface-active additives in the base lubricant (water), long-term lubricating performance based on "self-healing" properties is readily expected. In order to assess whether the superior aqueous lubricating properties of polyelectrolyte chains are valid for free polymers too, this study reviews recent studies on the tribological properties of many charged biopolymer and synthetic copolymers at a nonpolar, hydrophobic interface. In contrast to the irreversibly immobilized polyelectrolyte chains, free polyelectrolyte chains show inferior aqueous lubricating properties compared to their neutral counterparts owing to charge accumulation and the consequently impeded surface adsorption on the nonpolar surface. Nevertheless, bovine submaxillary mucin (BSM), a representative biopolymer, shows a sufficiently effective surface adsorption and aqueous lubricating capabilities even at neutral pH without losing the polyanionic characteristics.

• Corrosion Science and Technology
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• 제9권6호
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• pp.259-264
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• 2010

In continuous hot dip galvanizing process, oxide formation on steel surface has an influence on Zn wetting. High strength automotive steel contains high amount of Si and Mn, where Si-Mn composite oxides such as $Mn_2SiO_4$ or $MnSiO_3$ covers the surface after annealing. Zn wetting depends on how the aluminothermia reaction can reduce the Mn-Si composite oxides and then form inhibition layer such as $Fe_2Al_5$ on the steel surface. The outward diffusion of metallic ions such as $Mn^{2+}$, $Si^{2+}$ in the steel matrix is very important factor for the formation of the surface oxides on the steel surface. The surface state and grain boundaries provide an important role for the diffusion and the surface oxide reactions. Some elements such as P, Sb, and B have a strong affinity for the interface precipitation, and it influence the diffusivity of metallic ions on grain boundaries. B oxide forms very rapildly on the steel surface during the annealing, and this promote complex oxides with $SiO_2$ or MnO. P has inter-reacted with other elements on the grain boundaries and influence the diffusion through on them. Small addition of Sb could suppress the decarburization from steel surface and retards the formation of internal and external selective oxides on the steel surface. Interface control by the trace elements such as Sb could be available to improve the Zn wettability during the hot dip galvanizing.

• 한국시뮬레이션학회논문지
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• 제31권3호
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• pp.1-10
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• 2022

국방 분야는 아군 피해를 최소화하고 전투 효과를 향상하기 위해 무인 시스템을 운용한다. 해군의 무인수상정(USV, Swarm Unmanned Surface Vehicle)은 통신범위 내 군집 형성과 USV 간의 상황인식 정보공유를 통해 임무를 수행한다. 본 논문은 무인수상정의 내부 연동 및 외부 연동을 위한 인터페이스 연동어댑터 시스템(IAS, Interface Adapter System)을 제안한다. IAS는 USV의 자율운항 경로생성과 무장할당을 계획하는 임무계획 부체계(MPS, Mission Planning Subsystem)의 타 부체계 간 연동을 담당하며, 주요 기능은 MPS와 타 부체계 간 인터페이스 데이터를 실시간으로 교환하는 것이다. 이를 위해, MPS의 기능 요구사항과 연동 메시지를 식별 및 분석하였고, 실시간 분산처리 미들웨어를 활용하여 IAS를 구현하였다. 실험은 군집 USV 시뮬레이션 환경을 통한 다수의 통합시험을 수행하였으며, 지연시간과 연동 메시지 손실률을 측정하였다. 그 결과, 제안한 IAS는 MPS와 타 부체계 간 성공적인 가교역할을 수행할 것으로 기대한다.

• 한국광학회지
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• 제1권2호
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• pp.142-148
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• 1990

Sarid형의 감쇠 전반사 구조를 통하여 장거리 표면 프라즈몬을 여기시켜 은-피리딘 경계면에서 표면증강 라만산란 실험을 수행하였다. 장거리 표면 플라즈몬의 여기를 확인하기 위해 은을 $100\AA$으로 증착하여 실험한 결과, 그 진행을 눈으로 볼 수 있었다. 이것을 이용해서 은 표면에 흡착된 피리딘의 라만신호를 관측하여 체적 상태 및 화학적 흡착이 있는 경우의 피리딘의 라만신호와 비교, 분석하였는데 장거리 표면 프라즈몬을 이용한 표면증강 라만산란 실험을 아직까지 보고된 바 없다.

• 접착 및 계면
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• 제21권1호
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• pp.27-33
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• 2020

유리섬유강화 복합재료 (GFRC)의 표면거칠기에 따른 에폭시 접착제의 접착강도를 평가하였고 최적의 표면거칠기를 선정하였다. 서로 다른 입자크기의 알루미나 (Al2O3) 입자를 GFRC의 표면에 분사하였고 이를 통하여 서로 다른 표면거칠기를 부여하였다. 표면거칠기를 정량화 하였고 표면거칠기에 따른 표면관찰을 진행하였다. 각 표면거칠기에 따른 접촉각을 측정하였고 이를 통하여 표면에너지를 계산하였으며, 에폭시 접착제와의 접착일을 계산 및 비교하여 접착력을 예측하였다. 단일랩전단 시험을 통해 접착강도를 평가하였고 거칠기에 따라 접착강도가 증가된다는 것을 확인하였다. 박리 후 표면을 관찰해 보았을 때 기지재인 GFRC의 박리 정도가 다른 것을 확인하였고 최종적으로 표면거칠기의 최적조건을 확인할 수 있었다.