• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제51권4호
• /
• pp.175-183
• /
• 2002

In this paper, the surface modification effect of self-assembled monolayer(SAM) of 1-dodecanethiol [$CH_3$($CH_2$)$_{11}$SH] used as an anti-adhesive film in micromolding process was studied. Monolayers of 1-dodecanethiol[$CH_3$(CH$_2$)$_{11}$SH] were obtained by immersing a metal place in pure 1-dodecanethiol. SAM film on the nickel plate has been examined by using X-ray photoelectron spectroscopy(XPS). The focus has been placed on S-Ni bonding. From the XPS analysis, sulfur atoms were detected from the SAM film as a chemical composition of S-Ni. In order to measure an adhesion force of the SAM-coated nickel surface, atomic force microscopy(AFM) was used in force-distance mode, which whows the micro-adhesive force on solid surface. It was shown that adhesion forces measured from the SAM-coated nickel surface and the Ni surface without SAM coating were 3.52nN and 5.32nN, respectively. In order to investigate the effect of SAM coating on the surface foughness the replica in demolding process, hot embossing experiments were performed using a SAM-coated nickel master and a nickel master without SAM coating. Surface roughness of replica from the SAM-coated master showed 25nm and that of replica from master without SAM coating was 35nm. The smoother surface roughness of the replica from the SAM-coated, master is believed to result from reduction in the adhesion forces.ces.

• 한국건축시공학회지
• /
• 제23권6호
• /
• pp.683-692
• /
• 2023

본 연구에서는 보통 및 경량 굵은 골재를 사용한 콘크리트의 역학적 특성을 평가하기 위해 압축강도와 초음파 속도를 측정하였다. 압축강도에서는 재령 초기에서 보통골재 콘크리트가 높은 경향을 나타냈으나 시간 경과에 따라 경량골재 콘크리트가 높아지는 것을 알 수 있으며, 경량골재의 특징 중 높은 흡수율의 영향이라고 판단된다. 초음파 속도에서는 일정 시간을 제외하고 대부분 보통골재가 높은 경향을 나타냈으며, 골재의 내부 공극의 차이라고 판단된다. 압축강도와 초음파 속도의 상관관계를 통한 예측식의 상관계수(R²)가 0.95를 상회하며, 본 실험을 통한 예측식으로 강도 예측의 신뢰성이 높다고 판단된다.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1998년도 봄 학술발표회논문집(II)
• /
• pp.755-760
• /
• 1998

In the present, we have developed high strength concrete for the sleepers of high speed rail and verified its applicability by in-situ applications. Concrete for sleepers is manufactured by steam curing at low temperature(below 55$^{\circ}C$), and should be finished its manufacturing process such as placing, curing, demolding and prestressing in 24 hours. The sleepers need its compressive strength above 350kg/$\textrm{cm}^2$ in 15 hours, air-entrainment for durability and nominal design strength of 600kg/$\textrm{cm}^2$, considering its quality variation at factory. We performed the optimum mix design of concrete and verified the rightness of the use of TYPE III cement. Finally, we have confirmed the manufactured sleepers satisfy the required material properties through in-situ application.

• 마이크로전자및패키징학회지
• /
• 제22권1호
• /
• pp.1-5
• /
• 2015

Recently, data throughput of smart electric devices increases dramatically. There is a great interest in a new technology which exceeds the limit of electrical transmission method. Optical PCB can supplement the weakness of electrical signal processing, the research for optical PCB is very active. In this paper, we propose the thermal imprint lithography process to fabrication optical layer of optical PCB and experiment to optimize the process conditions. We confirm process time, pressure, process temperature, demolding temperature and fabricate optical interconnection structure which has $45^{\circ}$ tilted mirror surface for confirm the interconnection efficiency.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
• /
• pp.209-210
• /
• 2009

건축공사에서 측면 거푸집의 탈형시기와 관련하여 압축강도를 조기에 발현하는 것은 공기단축 및 경제성 측면에서 매우 중요하다. 이에, 본 연구에서는 콘크리트의 초기 강도발현에 미치는 광물질 흔 화재료의 종류 및 혼입률의 영향을 검토하였다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 C
• /
• pp.1887-1889
• /
• 2001

금속 재질의 MEMS 구조물의 모양을 폴리머에 전사하는 micromolding 과정에서 금속 구조물과 폴리머 사이를 분리 (demolding)시킬 때 금속 구조물과 폴리머 기판 사이에 분리를 방해하는 응착 (Adhesion) 문제가 발생한다. 이러한 응착 문제를 줄이고자 표면 에너지가 낮은 Self-Assembled Monolayer(SAM) coating을 금속(Ni) 표면에 시도하였다. SAM coating 막의 형성 여부와 응착력 (Adhesion force) 값을 구하기 위해 각각 XPS(X-ray photoelectron spectroscopy)와 AFM(Atomic force microscopy)을 이용하여 측정하였고 측정 결과 Ni 표면에 SAM이 형성되었음을 XPS로부터 알 수 있었고 SAM coating된 Ni 시편에서 더 낮은 응착력값을 보여 주었다.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2017년도 춘계 학술논문 발표대회
• /
• pp.152-153
• /
• 2017

In the construction site, it is necessary to estimate the compressive strength of concrete in order to adjust the demolding time of the form, and establish and adjust the construction schedule. The compressive strength of concrete is determined by various influencing factors. However, the conventional method for estimating the compressive strength of concrete has been suggested by considering only 1 to 3 specific influential factors as variables. In this study, six influential factors (Water, Cement, Fly ash, Blast furnace slag, Curing temperature, and humidity) of papers opened for 10 years were collected at three conferences in order to know the various correlations among data and the tendency of data. After using algorithm of various methods of machine learning techniques, we selected the most suitable regression analysis model for estimating the compressive strength.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
• /
• pp.639-642
• /
• 2002

A new PDP barrier rib formation technique was investigated utilizing transparent soft maid made of silicon resin. Transparent soft mold was fabricated by pouring a silicone resin into the base mold made with photosensitive glass. The photosensitive barrier rib paste was coated on the glass substrate and dried in a 90 $^{\circ}C$ convection oven for 20min. The transparent soft mold was pressed on top of the semi-dry barrier rib layer and then irradiated with a UV lamp to a total dose of $900{\sim}1000mJ/cm^2$ The soft maid was then removed from the pressed barrier rib by winding up and fine pattern of barrier rib was obtained. The photosensitive barrier rib paste makes the demolding easy due to reduced interfacial forces and shrinking of paste materials.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2004년도 추계학술대회논문집
• /
• pp.305-310
• /
• 2004

The Hot Embossing Lithography(HEL) as a method for the fabrication of nanostructure with polymer is becoming increasingly important because of its simple process, low cost, high replication fidelity and relatively high throughput. In this study, we investigated the characteristics of hot embossing lithography as a nanoreplication technique. To grasp characteristics of nano patterning rheology by process parameters(embossing temperature, pressure and time), we have carried out various experiments by using the DVD(400nm pattern width) and Blu-ray nickel stamps(150nm pattern width). During the hot embossing process, we have observed the characteristics of the size effect. The quality of products made by hot embossing is affected by its cooling shrinkage. The demolding process at the glass transition temperature results in low quality because of the shrinkage of the polymer. Therefore, the quantification of the temperature condition is essential for the replication of high quality.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2004년도 추계학술대회논문집
• /
• pp.284-289
• /
• 2004

Since polymer materials at elevated temperatures are usually rate-sensitive, the analysis of RTP process requires considering the effect of the rate-dependent. The material behavior that exhibits rate-sensitivity is called visco-plastic. A two-dimensional visco-plastic finite element formulation which constitutive equation is based on the formulation proposed by Perzyna is presented. This Paper is purposed to calcuate pressure distribution on PMMA in compression process and to predict the relationship with defects after demolding process. This paper analyzes, both analytically and numerically, the pressure distributions on the surface of PMMA during open-die RTP process. In this research, PMMA is used to be simulated at $110^{\circ}C$ near the transition temperature.