• International Journal of Precision Engineering and Manufacturing
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• v.9 no.1
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• pp.25-29
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• 2008

We introduce a new fabrication process for antireflective structured surfaces. A 4-inch silicon wafer was dipped in a suspension of 300-nm-diameter silica particles dispersed in a toluene solution. When the wafer was drawn out of the suspension, a hexagonally packed monolayer structure of particles self-assembled on almost the complete wafer surface. Due to the simple process, this could be applied to micro- and nano-patterning. The self-assembled silica particles worked as a mask for the subsequent reactive ion etching. An array of nanometer-sized pits could be fabricated since the regions that correspond to the small gaps between particles were selectively etched off. As etching progressed, the pits became deeper and combined with neighboring pits due to side-etching to produce an array of cone-like structures. We investigated the effect of etching conditions on antireflection properties, and the optimum shape was a nano-cone with height and spacing of 500 nm and 300 nm, respectively. This nano-structured surface was prepared on a $30\;{\times}\;10-mm$ area. The reflectivity of the surface was reduced 97% for wavelengths in the range 400-700 nm.

• JSTS:Journal of Semiconductor Technology and Science
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• v.1 no.1
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• pp.20-30
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• 2001

A 1.8V $650{\;}\textrm{mm}^2$ 4Gb DRAM having $0.10{\;}\mu\textrm{m}^2$ cell size has been successfully developed using 0.11 $\mu\textrm{m}$DRAM technology. Considering manufactur-ability, we have focused on developing patterning technology using KrF lithography that makes $0.11{\;}\mu\textrm{m}$ DRAM technology possible. Furthermore, we developed novel DRAM technologies, which will have strong influence on the future DRAM integration. These are novel oxide gap-filling, W-bit line with stud contact for borderless metal contact, line-type storage node self-aligned contact (SAC), mechanically stable metal-insulator-silicon (MIS) capacitor and CVD Al process for metal inter-connections. In addition, 80 nm array transistor and sub-80 nm memory cell contact are also developed for high functional yield as well as chip performance. Many issues which large sized chip often faces are solved by novel design approaches such as skew minimizing technique, gain control pre-sensing scheme and bit line calibration scheme.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.159-159
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• 2004

금속 박막 위의 알칸티올분자의 흡착에 의한 자기조립단분자막(Self-Assembled Monolayers)은 접착 방지, 마찰 저하 등의 기능을 가진 코팅층으로서의 응용과 분자 또는 생분자의 미세 구조물 형성을 위한 방법으로 널리 연구되어지고 있다. 이러한 연구 중에서 특히 자기조립단분자막의 매우 얇은 두께와 금속 박막의 선택적 식각을 위한 안정적인 리지스트(Photo Resist)로서의 특징을 활용한 극미세 패터닝에 대한 연구가 활발히 진행되고 있다.(중략)

• Applied Science and Convergence Technology
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• v.25 no.1
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• pp.1-6
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• 2016

Quantum dots (QDs) are considered as excellent color conversion and self-emitting materials for display and lighting applications. In this article, various technologies which can be used to realize white light emission with QDs are discussed. QDs have good color purity with a narrow emission spectrum and tunable optical properties with size control capabilities. For white light emission with a color-conversion approach, QDs are combined with blue-emitting inorganic and organic light-emitting diodes (LED) to generate white emission with high energy conversion efficiency and a high color rendering index for various display and lighting applications. Various device structures for self-emitting white QD light-emitting diodes (QD-LED) are also reviewed. Various stacking and patterning technologies are discussed in relation to QD-LED devices.

• Korean Journal of Ecology and Environment
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• v.43 no.4
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• pp.477-491
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• 2010

Benthic macroinvertebrates were collected two times from 116 sites at the $1^{st}{\sim}4^{th}$ order streams in forest areas in Gyungsang province in late spring and late summer. The sample sites belonged to slightly and moderately polluted states. When communities were classified by the Self-Organizing Map (SOM), the gradient was observed according to degree of pollution. Within clusters of slightly polluted sites, however, seasonality was further observed. Scrapers, gatherer-collectors, and filterer-collectors were abundantly observed in late spring while shredders appeared more in late summer. The number of predator species increased in late summer. Behavior types were mostly clingers in two seasons. Community compositions at the moderately polluted sites were not much differentiated in different seasons. Gatherer-collectors and burrowers were dominantly collected in both seasons.

• Environmental Analysis Health and Toxicology
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• v.23 no.4
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• pp.231-245
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• 2008

Various methods for detecting changes in response behaviors of indicator specimens are presented for monitoring effects of toxic treatments. The movement patterns of individuals are quantitatively characterized by statistical (i.e., ANOVA, multivariate analysis) and computational (i.e., fractal dimension, Fourier transform) methods. Extraction of information in complex behavioral data is further illustrated by techniques in ecological informatics. Multi-Layer Perceptron and Self-Organizing Map are applied for detection and patterning of response behaviors of indicator specimens. The recent techniques of Wavelet analysis and line detection by Recurrent Self-Organizing Map are additionally discussed as an efficient tool for checking time-series movement data. Behavioral monitoring could be established as new methodology in integrative ecological assessment, tilling the gap between large-scale (e.g., community structure) and small-scale (e.g., molecular response) measurements.

• Journal of Microbiology and Biotechnology
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• v.29 no.12
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• pp.1861-1872
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• 2019

In the present work, we isolated and identified Aspergillus sydowii NYKA 510 as the most potent laccase producer. Its medium constituents were optimized to produce the highest possible amount of laccase, which was after 7 days at 31℃ and pH 5.2. Banana peel and peptone excelled in inducing laccase production at concentrations of 15.1 and 2.60 g/l, respectively. Addition of copper sulfate elevated enzyme yield to 145%. The fungus was employed in a microbial fuel cell (MFC). The best performance was obtained at 2000 Ω achieving 0.76 V, 380 mAm^-2, 160 mWm^-2, and 0.4 W. A project to design a self-sufficient lighting unit was implemented by employing a system of 2 sets of 4 MFCs each, connected in series, for electricity generation. A scanning electron microscopy image of A. sydowii NYKA 510 was utilized in algorithmic form generation equations for the design. The mixed patterning and patterned customized mass approach were developed by the authors and chosen for application in the design.

• Korean Journal of Environmental Biology
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• v.26 no.3
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• pp.203-213
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• 2008

Benthic macro invertebrate communities were collected at six different sampling sites in the Musucheon stream in Korea from July 2006 to July 2007, and ecological exergy values were calculated based on five different functional feeding groups (collector-gatherer, collector-filterer, predator, scrapper, and shredder) of benthic macro invertebrates. Each sampling site was categorized to three stream types (perennial, intermittent and drought) based on the water flow condition. Exergy values were low at all study sites right after a heavy rain and relatively higher in the perennial stream type than in the intermittent or the drought stream type. Self-Organizing Map (SOM), unsupervised artificial neural network, was implemented to pattern spatial and temporal dynamics of ecological exergy of the study sites. SOM classified samples into four clusters. The classification reflected the effects of floods and droughts on benthic macroinvertebrate communities, and was mainly related with the stream types of the sampling sites. Exergy values of each functional feeding group also responded differently according to the different stream types. Finally, the results showed that exergy is an effective ecological indicator, and patterning changes of exergy using SOM is an effective way to evaluate target ecosystems.

• Journal of the Korean Vacuum Society
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• v.15 no.1
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• pp.97-102
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• 2006

Anodic alumina with self-organized and ordered nano hole arrays can be a good candidate of an irradiation mask to modify the properties of nano-scale region. In order to try using porous anodic alumina as a mask for ion-beam patterning, ion beam transmittance of anodic alumina was tested. 4 Um thick self-standing AAO templates anodized from Al bulk foil with two different aspect ratio, 200:1 and 100:1, were aligned about incident ion beam with finely controllable goniometer. At the best alignment, the transmittance of the AAO with aspect ratio of 200:1 and 100:1 were $10^{-8}\;and\;10^{-4}$, respectively. However transmittance of the thin film AAO with low aspect ratio, 5:1, were remarkably improved to 0.67. The ion beam transmittance of self-standing porous alumina with a thickness larger than $4{\mu}m$ is extremely low owing to high aspect ratio of nano hole and charging effect, even at a precise beam alignment to the direction of nano hole. $SiO_2$ nano dot array was formed by ion irradiation into thin film AAO on $SiO_2$ film. This was confirmed by scanning electron microscopy that the $SiO_2$ nano dot array is similar to AAO hole array.

• Elastomers and Composites
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• v.34 no.1
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• pp.45-52
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• 1999

This paper describes how the gold particles self assemble on the specific phase on the microphase separated block copolymer thin film and form a well ordered patterns. For this study, polystyrene-polybutadiene-polystyrene (PS-PB-PS) triblock copolymer (30wt % PS) thin films (${\sim}100nm$) having a cylindrical morphology were cast from 0.1wt% toluene solution to be used as polymer thin film templates. The films having either vertical PS cylinders or in-plane PS cylinders in PB matrix from each different solvent evaporation condition were obtained. Cross-sectional transmission electron microscopy(TEM) was used to study the surface and bulk morphologies of block copolymer thin films. Small amount of gold particles was evaporated on a block copolymer thin film template to obtain a nano-scale pattern. When an as-cast thin film template was used, gold particles preferentially self assemble on the low surface tension PB phase and a relatively well ordered pattern in nano-scale was produced. However, after the formation of a low surface energy PB rich layer upon annealing, a gold self-assembled pattern was not observed.