• 폴리머
• /
• 제24권5호
• /
• pp.721-727
• /
• 2000

탄소섬유/에폭시 수지 복합재료의 기계적 계면 결합력을 증가시키기 위해 탄소섬유를 전해 니켈도금 표면처리하였다. 탄소섬유의 표면특성과 복합재료의 최종 기계적 물성은 각각 X-ray photoelectron spectroscopy (XPS)와 Interlaminar shear strength (ILSS) 측정을 통하여 알아보았다. 본 실험결과, 전해 니켈도금은 복합재료의 계면, 즉 강화재인 탄소섬유와 매트릭스간의 계면 결합력에 크게 영향을 미침을 알 수 있었으며, 특히 니켈도금 처리된 탄소섬유 표면에서 $O_{1s}$/$C_{1s}$ 비의 증가와 NiO 그룹 및 금속 니켈의 형성은 기계적 특성인 ILSS 증가의 요인으로 작용함을 알 수 있었다 또한, $O_{1s}$/$C_{1s}$비는 복합재료의 ILSS와 밀접한 관계가 있음을 고찰하였다.을 고찰하였다.

• 한국자기학회지
• /
• 제22권5호
• /
• pp.157-161
• /
• 2012

각기 암염구조를 가지는 sp 반쪽금속인 NaN과 CaN가 계면상태를 이룰 때의 반쪽금속성 및 자성을 연구하기 위해 단순계면계와 혼합계면계 두 계를 고려하여, FLAPW(full-potential linearized augmented plane wave) 방법을 이용하여 그 전자구조를 계산하였다. 계산된 원자별 자기모멘트를 보면, 단순계면계에서는 Na 쪽 계면 N 원자의 자기모멘트는 안쪽 N 원자에 비해 다소 감소하였고, Ca 쪽 계면 N원자의 경우는 다소 증가하였다. 혼합계면계에서는 계면 N 원자들의 자기모멘트는 대략 덩치 CaN과 NaN에서 N 원자의 자기모멘트 값의 평균치를 가졌으나, 아래 위층 모두에서 Na와 연결된 계면 N 원자의 자기모멘트가 가장 컸고, 아래 위층 모두에서 Ca 원자와 연결된 계면 N 원자의 자기모멘트가 가장 작았다. 이와 같은 상황은 각각의 N 원자가 이웃한 Ca나 Na 원자와 결합하면서 결합에 참여하지 않은 p 전자수가 자기모멘트의 크기를 결정한다는 사실과 부합한다. 또한 계산된 원자별 상태밀도를 통해 이들의 계면상태를 논의하였다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
• /
• pp.413-413
• /
• 2014

In this paper, we present a fabrication method of functionalized gold nanostructures on flexible substrate that can be implemented for plasmonic sensing application. For biomolecular sensing, many researchers exploit unconventional lithography method like nanoimprint lithography (NIP), contact transfer lithography, soft lithography, colloidal transfer printing due to its usability and easy to functionalization. In particular, nanoimprint and contact transfer lithography need to have anti-adhesion layer for distinctive metallic properties on the flexible substrates. However, when metallic thin film was deposited on the anti-adhesion layer coated substrates, we discover much aggravation of the mold by repetitive use. Thus it would be impossible to get a high quality of metal nanostructure on the transferred substrate for developing flexible electronics based transfer printing. Here we demonstrate a method for nano-pillar mold and transfer the controllable nanoparticle array on the flexible substrates without an anti-adhesion layer. Also functionalization of gold was investigated by the different length of thiol applied for effectively localized surface plasmonic resonance sensing. First, a focused ion beam (FIB) and ICP-RIE are used to fabricate the nanoscale pillar array. Then gold metal layer is deposited onto the patterned nanostructure. The metallic 130 nm and 250 nm nanodisk pattern are transferred onto flexible polymer substrate by bi-layer functionalized contact imprinting which can be tunable surface energy interfaces. Different thiol reagents such as Thioglycolic acid (98%), 3-Mercaptopropionic acid (99%), 11-Mercaptoundecanoic acid (95%) and 16-Mercaptohexadecanoic acid (90%) are used. Overcoming the repeatedly usage of the anti-adhesion layer mold which has less uniformity and not washable interface, contact printing method using bi-layer gold array are not only expedient access to fabrication but also have distinctive properties including anti-adhesion layer free, functionalized bottom of the gold nano disk, repeatedly replicate the pattern on the flexible substrate. As a result we demonstrate the feasibility of flexible plasmonic sensing interface and anticipate that the method can be extended to variable application including the portable bio sensor via mass production of stable nanostructure array and other nanophotonic application.

• 한국윤활학회:학술대회논문집
• /
• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
• /
• pp.227-228
• /
• 2002

One of the serious challenges in developing rotary compressor with HFC refrigerant is the prediction of scuffing times and wear amounts between vane and roller surface. In this study, the tribological characteristics of sliding surfaces using roller-vane geometry of rotary compressor were investigated. The sliding tests were carried out under various sliding speeds, normal loads and surface roughness. During the tests, friction force, wear scar width, time to failure, surface temperature, and surface roughness were monitored. Because severe wear was occurred on vane surface, TiN coating was applied on sliding surfaces to prolong the wear-life of vane-roller interfaces. From the sliding tests, it was found that there was the optimum initial surface roughness to break in and to prolong the wear life of sliding surfaces. Depending on load and speed, the protective layers, which were composed of metallic oxide and organic compound, were formed on sliding surfaces. Those would play an important role in the amount of friction and wear between roller and vane surfaces.

• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
• /
• pp.221-226
• /
• 2002

One of the serious challenges in developing rotary compressor with HFC refrigerant is the prediction of scuffing times and wear amounts between vane and roller surfaces. In this study, the tribological characteristics of sliding surfaces using vane-roller geometry of rotary compressor were investigated. The sliding tests were carried out under various sliding speeds, normal loads and surface roughness. During the test friction force, wear depth, time to failure and surface temperature were monitored. Because severe wear was occurred on vane surface, TiN coating was applied on sliding surfaces to prolong the wear-life of vane-roller interfaces. From the sliding test it was found that there was the optimum initial surface roughness to break in and to prolong the wear life of sliding surfaces. Depending on the load and speed, the protective layers, which were composed of metallic oxide and organic compound, were formed on sliding surfaces. Those would play an important role in role amounts of friction and wear between miler and vane surfaces.

• 한국진공학회지
• /
• 제8권4B호
• /
• pp.514-518
• /
• 1999

Gold (Au) is not supposed to react with sapphire(single crystalline ) under thermodynamic equillibrium, therefore, a strong adhesion between these two dissimilar materials is not expected. However, pull test showed that the gold film sputter-deposited onto annealed and pre-sputtered sapphire exhibited very strong adhesion even without post-deposition annealing. Strongly and weakly adhered samples as a result of the pull testing were selected to investigate the adhesion mechanisms with Auger electron spectroscopy. The Au/ interfaces were analyzed using a new technique that probes the interface on the film using Auger electron escape depth. It revealed that one or two monolayers of Au-Al-O compound formed at the Au/Sapphire interface when AES in the UHV chamber. It showed that metallic aluminum was detected on the surface of sapphire substrates after irradiating for 3 min. with 7keV Ar+ -ions. These results agree with TRIM calculations that yield preferential ion-beam etching. It is concluded that the formation of Au-Al-O compound, which is responsible for the strong metal-ceramic bonding, is due to ion-induced cleaning and reduction of the sapphire surface, and the kinetic energy of depositing gold atoms, molecules, and micro-particles as a driving force for the inter-facial reaction.

• Tribology and Lubricants
• /
• 제20권6호
• /
• pp.337-342
• /
• 2004

One of the serious challenges in developing rotary compressor with HFC refrigerant is the prediction of scuffing times and wear amounts between vane and roller surfaces. In this study, the tribological characteristics of sliding surfaces using vane-roller geometry of rotary compressor were investigated. The sliding tests were carried out under various sliding speeds, normal loads and surface roughness. During the test, friction force, wear depth, time to failure and surface temperature were monitored. Because severe wear occurred on vane surface, TiN coating was applied on sliding surfaces to prolong the wear life of vane-roller interfaces. From the sliding test it was found that there was the optimum initial surface roughness to break in and to prolong the wear life of sliding surfaces. Depending on the load and speed, the protective layers, which were composed of metallic oxide and organic compound, were formed on sliding surfaces. Those would play an important role in the amounts of friction and wear between roller and vane surfaces.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 C
• /
• pp.1102-1104
• /
• 1999

It is very essential to find out defects and remove them in the insulation at the early stage because the defects in the insulation induce PD which deteriorates the material, resulting in the breakdown. In the real application of high voltage, the interface of the different insulation is the weakest place for both electrical and mechanical aspects. In this paper, characteristics of PD caused by the artificial defects, such as metallic particles, voids and moist fibers, at the interfaces of the cable joint (PJB) were investigated using the specially designed electrode system.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
• /
• pp.211-211
• /
• 2011

Nanostructures, with a diversity of shapes, built on substrates have been developed within many research areas. Lithography is one powerful, but complex, technique to make structures at the nanometer scale, such as platinum nanowires for studying CO catalytic reactions [1], or aluminum nanodisks for studying the plasmon effect [2]. In this work, we approach a facile method to construct nanostructures using noble metals on a titania thin film by using self-assembled structures as a pattern. Here, a large-scale silica monolayer is transferred to the titania thin film substrates using a Langmuir-Blodgett trough, followed by the deposition of a thin transition metal layer. Owing to the hexagonal close-packed structure of the silica monolayer, we would obtain a metal nanostructure that includes separated metallic triangles (islands) after removing the patterning silica beads. This nanostructure can be employed to investigate the role of metal-oxide interfaces in CO catalytic reactions by changing the patterning silica particles with different sizes or by replacing the oxide support. The morphology and chemical composition of the structure can be characterized by scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy. In addition, we modify these islands to a connected island structure by reducing the silica size of the patterning monolayer, which is utilized to generating hot electron flow based on the localized surface plasmon resonance effect of the metal nanostructures.

• 한국자기학회지
• /
• 제16권2호
• /
• pp.130-135
• /
• 2006

강자성체/비자성 금속/강자성체/반도체 구조에서 층간교환강호작용(interlayer exchange coupling) 에너지가 외부 인가전압으로 제어 가능함을 이론적으로 보였다. 비자성 금속층으로 격리된 두 강자성층 사이의 층간교환상호작용 에너지는 강자성체/비자성 금속 계면에서 전자의 스핀에 의존하는 반사율의 차이에 의해 결정된다는 것은 잘 알려진 사실인데, 이를 각자성체/비자성 금속/강자성체/반도체 구조에 적용하여 층간교환상호작용 에너지가 강자성체/비자성 금속/강자성체 계면에서 전자의 반사율뿐 아니라 강자성체/반도체 계면에서의 반사율에도 의존한다는 것을 보였다 강자성체/반도체 계면에 생기는 Schottky 장벽의 높이와 두께는 인가전압으로 바꿀 수 있고, 그에 따른 전자의 반사율이 인가전압에 의해 바뀔 수 있음을 알 수 있었다. 결과적으로 일차원 자유전자 모델을 사용하여 외부 인가 전압으로써 두 강자성체 사이의 층간 교환 상호작용 에너지를 제어할 수 있다는 것을 확인하였다.