• Journal of the Korean Society for Nondestructive Testing
• /
• v.30 no.5
• /
• pp.489-496
• /
• 2010

The power generation and chemical industry have been subjected to further material degradation with long term operations and need to predict the remaining service life of components, such as reformer tube and steam turbine rotor, that have operated at elevated temperatures. As a non-destructive technique, replication method with reliable metallurgical life and microstructural soundness assessment has been recognized with strongly useful method until now. Developments of this method have variously accomplished by new quantitative approach, such as carbide analysis, with A-parameter and grain deformation method. An overview of replication, some new techniques for material degradation and life assessment were introduced in this paper. Also, on-site applications and its reasonableness were described. As a result of having analyzed microstructure by replication method, carbide approach was quantitatively useful to life assessment.

• Journal of the KSME
• /
• v.44 no.12
• /
• pp.34-38
• /
• 2004

이 글에서는 최근 마이크로/나노 구조물에 대한 고분자 나노복제 공정에 있어서 그 중요성이 대두되고 있는 나노몰드 표면온도 제어기술에 대해 소개하고자 한다.

• 한국가스학회:학술대회논문집
• /
• 1999.09a
• /
• pp.54-60
• /
• 1999

• 열병합발전
• /
• s.44
• /
• pp.11-16
• /
• 2005

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2008.11a
• /
• pp.139-139
• /
• 2008

나노 임프린트 리소그래피 방법을 이용하여 매미 날개의 표면구조를 열가소성 고분자 시트 위에 역상으로 전사하였다. 그 후 표면구조가 형성된 시트의 UV-가시광선 투과도와 증류수의 접촉각을 측정함으로써 표면구조 형성을 통해 난반사 효과와 자가 세정 효과를 부여하였음을 확인하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2009.10a
• /
• pp.248-248
• /
• 2009

GaN 기반 LED 소자의 ITO 표면에 sol-imprinting 기술을 이용하여 잔여층 없이 $TiO_2$ 나노 패턴을 형성하였다. 알콕사이드 계열의 $TiO_2$ sol과 Si 몰드로부터 복제된 PDMS 몰드를 사용하여 표면에 패턴을 형성하고, 이 후 annealing을 통해 내부에 남아있던 불순물을 제거하고 다결정 $TiO_2$을 형성하였다. 표면에 형성된 $TiO_2$ 나노 패턴이 LED 소자 내부에서 발생한 빛의 전반사를 억제하기 때문에 소자의 광추출 효율이 증가하였다.

• Composites Research
• /
• v.20 no.2
• /
• pp.17-20
• /
• 2007

Superhydrophobic polytetrafluoroethylene ($Teflon^{(R)}$, Dupont) sub-micro and nanostructures were fabricated by the dipping method, based on anodization process in oxalic acid. The polymer sticking phenomenon during the replication creates the sub-microstructures on the negative polytetrafluoroethylene nanostructure replica. This process gives a hierarchical structure with nanostructures on sub-microstructures, which looks like the same structures as lotus leaf and enables commercialization. The diameter and the height of the replicated nano pillars were 40 nm and 40 um respectively. The aspect ratio is approximately 1000. The fabricated surface has a semi-permanent superhydrophobicity, the apparent contact angle of the polytetrafluoroethylene sub-micro and nanostructures is about $160^{\circ}$, and the sliding angle is less than $1^{\circ}$.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.24 no.9 s.180
• /
• pp.2381-2386
• /
• 2000

Surface replication is playing an important role in the assessment of creep damage and remaining life of high temperature components. As the replication procedures, however, have not been standardized in domestic industry, its standardization is proposed in this study. For this purpose, the 2.25Cr-IMo steel was heat treated(5 min at 1,300 0C and oil quenched) to produce a simulated HAZ microstructure, and crept in air at 575 0C and under 120 MPa to produce artificial cavities. Then, the effect of surface preparation procedures on the quality of replicas was investigated using this sample. As a result, it was demonstrated that the presence of cavities may be observed readily or missed depending on the surface preparation procedures followed. Therefore it is essential to repeat three polishing/etching cycles at least in order to reveal cavitation damage accurately, even though it may be tedious or time-consuming.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.39 no.1
• /
• pp.71-77
• /
• 2015

Ultrasonic imprinting is a micropattern replication technology for a thermoplastic polymer surface that uses ultrasonic vibration energy; it has the advantages of a short cycle time and low energy consumption. Recently, ultrasonic imprinting has been further developed to extend its functionality: (i) selective ultrasonic imprinting using mask films and (ii) repetitive ultrasonic imprinting for composite pattern development. In this study, selective ultrasonic imprinting was combined with repetitive imprinting in order to replicate versatile micropatterns. For this purpose, a repetitive imprinting technology was further extended to utilize mask films, which enabled versatile micropatterns to be replicated using a single mold with micro-prism patterns. The replicated hybrid micropatterns were optically evaluated through laser light images, which showed that versatile optical diffusion characteristics can be obtained from the hybrid micropatterns.

• Journal of the Korean Vacuum Society
• /
• v.19 no.2
• /
• pp.96-104
• /
• 2010

We suggest here a cost-effective replica fabrication method for transparent and hard molds for imprinting lithography such as NIL and S-FIL. The process starts with the use of a replica hard mold from a master, using a polymer copy as a carrier. The polymer copy as a carrier was treated by soluble process for forming anti-adhesion layer. Duplicated hard molds can eliminate direct contact between a hard master and a patterned polymer on a substrate and the generated contamination of a master during the imprinting process. The replica hard mold exhibits the glass-like properties introduced here, such as transparency and hardness, make it appropriate for nanoimprint lithography and step-and-flash imprint lithography.