• Applied Chemistry for Engineering
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• v.34 no.1
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• pp.30-35
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• 2023

The glass bead surface was coated using a TiO₂ sol, after which dry-treated (TB) and calcined (TBc) samples were prepared. Photocatalytic degradation of methylene blue and toluene, as well as characterization of the TiO₂ thin films, were carried out. The TiO₂ thin film of the TB sample had the same shape as the sponge foam, according to FE-SEM, XPS, and FTIR analyses, and contained both amorphous and crystalline TiO₂. On the other hand, crystalline TiO₂ was mainly present in the TiO₂ thin film of the TBc sample, and needle-shaped particles and tiny ones were mixed. The adsorption capacity for methylene blue and the degradation rate of the TBc sample were less than 10 % compared with those of the TB sample, and the adsorption capacity and degradation rate of the TBc sample decreased similarly as the amount of TiO₂ coating increased. The amount of toluene adsorption for the TBc sample (46 mg/g) was smaller than that of the TB sample with the same coating amount, but the degradation rate was similar. In the case of the TB sample, the degradation rate for toluene decreased less than the adsorption capacity as the amount of TiO₂ coating increased. This result is considered to be because, in the non-calcined TB sample, the active site reduction of the crystalline particles occurred less and the specific surface area of the amorphous texture decreased as the amount of TiO₂ coating increased.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.2
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• pp.137-142
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• 2004

In this study, a simple procedure is described for patterning biotin on a glass substrate and then selectively immobilizing proteins of interest onto the biotin-patterned surface. Microcontact printing (CP) was used to generate the micropattern of biotin and to demonstrate the selective immobilization of proteins by using enhanced green fluorescent protein (EGFP) as a model protein, of which the C-terminus was fused to a core streptavidin (cSA) gene of Streptomyces avidinii. Confocal fluorescence microscopy was used to visualize the pattern of the immobilized protein (EGFP-cSA), and surface plasmon resonance was used to characterize biological activity of the immobilized EGFP-cSA. The results suggest that this strategy, which consists of a combination of $\mu$CP and cSA-fused proteins. is an effective way for fabricating biologically active substrates that are suitable for a wide variety of applications. one such being the use in protein-protein assays.

• Journal of Korean Association for Spatial Structures
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• v.20 no.1
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• pp.61-67
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• 2020

In the era of the Fourth Industrial Revolution, Various attempts are being made to converge new industries with IT industry to find new growth engines in the field of IT, maximizing efficiency in terms of productivity. 3D printers are also related to this, and various studies have been conducted worldwide to utilize them in the construction industry. At present, there is an active effort to study atypical structures using 3D printers. The most widely used method is the use of glass panels, however, the additional cost of the manufacturing process and thus the overall project cost cannot be ignored. In addition, the construction of the curvature of the existing two-way curved surface in the conventional flat joint method is not suitable for implementing an amorphous shape. In this paper, we propose an optimized shape through Abaqus analysis of various shapes of Space Truss interior using 3D printing technology using polymer.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.99-99
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• 2010

Recently, amorphous transparent oxide semiconductors (TOS) have been widely studied for many optoelectronic devices such as AM-OLED (active-matrix organic light emitting diodes). The TOS TFTs using a-IGZO channel layers exhibit a high electron mobility, a smooth surface, a uniform deposition at a large area, a high optical transparency, a low-temperature fabrication. In spite of many advantages of the sputtering process such as better step coverage, good uniformity over large area, small shadow effect and good adhesion, there are not enough researches about characteristics of a-IGZO thin films. In this study, therefore, we focused on the electrical properties of a-IGZO thin films as a channel layer of TFTs. TFTs with the a-IGZO channel layers and Y2O3 gate insulators were fabricated. Source and drain layers were deposited using ITO target. TFTs were deposited on unheated non-alkali glass substrates ($5cm{\times}5cm$) with a sintered ceramic IGZO disc (3 inch $\varnothing$, 5mm t), Y2O3 disc (3 inch $\varnothing$, 5mm t) and ITO disc (3 inch $\varnothing$, 5mm t) as a target by magnetron sputtering method. The O2 gas was used as the reactive gas. Deposition was carried out under various sputtering conditions to investigate the effect of sputtering process on the characteristics of a-IGZO thin films. Correlation between sputtering factors and electronic properties of the film will be discussed in detail.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.6
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• pp.560-570
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• 2005

In this paper, a microelectrode away DNA chip was fabricated on glass slide using photolithography technology. Several probe DNAs consisting of mercaptohexyl moiety at their 5' end were immobilized on the gold electrodes by DNA arrayer utilizing the affinity between gold and sulfu. Then target DNAs were hybridized and reacted with Hoechst 33258, which is a DNA minor groove binder and electrochemically active dye. Cyclic voltammetry in 5mA ferricyanide/ferrocyanide solution at 100 mV/s confirmed the immobilization of probe DNA on the gold electrodes. Linear sweep voltammetry or cyclic voltammetry showed a difference between target DNA and control DNA in the anodic peak current values. It was derived from Hoechst 33258 concentrated at the electrode surface through association with formed hybrid. It suggested that this DNA chip could recognize the sequence specific genes. It suggested that multichannel electrochemical DNA microarray is useful to develop a portable device for clinical gene diagnostic system.

• Carbon letters
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• v.6 no.2
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• pp.101-105
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• 2005

Like bamboo-sprouts after rains, numerous sub${\mu}m$-sized pyrocarbon whiskers growth on the Mullite ($3Al_2O_3{\cdot}2H_2O$) substrate could be observed through a looking glass during methane pyrolysis at the temperature of $1050^{\circ}C$ in this study. If the surface of substrate would be scrubbed strongly with iron metals, then finely sticked iron particles were more effective catalytic for nm-sized whisker growth. Numerous fine flakes of pyrolytic carbon were hanging by invisible nm-whiskers as like as small spiders hanging by a spiderweb. This is the identification of nm-sized whisker growth. Therefore if the pyrolysis would be stopped at the initial stage of the whisker growth, the primary lengthening growth was nm-sized whisker. So could we vary arbitrarily sizes of whisker from nm- to ${\mu}m$-sizes. But ${\mu}m$- and nm-whiskers grown with the different growth mechanism; the former was straight and the latter has twigs, The lengthening growth of whisker was depended on the flow pattern pyrolysis species on the active sites of substrate and on the growth duration. We could obtained straight whisker length of 10~20 ${\mu}m$/min during the primary growth and laboratory spiral whisker of 30~40 ${\mu}m$-diameter/hr during the secondary growth.

• Korean Journal of Materials Research
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• v.30 no.11
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• pp.595-600
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• 2020

The photovoltaic properties of perovskite solar cells (PSCs) with a carbon electrode fabricated using different annealing processes are investigated. Perovskite formation (50 ℃, 60 min) using a hot-plate and an oven is carried out on cells with a glass/fluorine doped TiO₂/TiO₂/ZrO₂/carbon structure, and the photovoltaic properties of the PSCs are analyzed using a solar simulator. The microstructures of the PSCs are characterized using an optical microscope, a field emission scanning electron microscope, and an electron probe micro-analyzer (EPMA). Photovoltaic analysis shows that the energy conversion efficiency of the samples fabricated using the hot-plate and the oven processes are 2.08% and 6.90%, respectively. Based on the microstructure of the samples and the results of the EPMA, perovskite is formed locally on the carbon electrode surface as the γ-butyrolactone (GBL) solvent evaporates and moves to the top of the carbon electrode due to heat from the bottom of the sample during the hot plate process. When the oven process is used, perovskite forms evenly inside the carbon electrode, as the GBL solvent evaporates extremely slowly because heat is supplied from all directions. The importance of the even formation of perovskite inside the carbon electrode is emphasized, and the feasibility of oven annealing is confirmed for PSCs with carbon electrodes.

• Korean Journal of Optics and Photonics
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• v.7 no.2
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• pp.101-111
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• 1996

Optical microscopes integrated with CCD cameras are widely used for automatic inspection of precision circuit patterns fabricated on glass masks and silicon wafers. For this application it is important to position the object always is focus so that the image appears in good quality while the microscope scans the object. However, as the magnification of the microscope is taken large for fine resolution the depth of focus becomes small, often in submicron ranges, requiring special care in focusing. This study proposes a new auto-focusing method, which can be readily incorporated in existing optical configuration of microscope. This method is based on optical triangulation using a separate beam of laser and two photodiodes, eliminating focus errors caused by surface roughness and waviness. Experimental results prove that the method can produce focus error signals which are very sensitive with a resolution of 5 nm within 0.5 ${\mu}{\textrm}{m}$ accuracy.

• Journal of Hydrogen and New Energy
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• v.28 no.1
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• pp.63-69
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• 2017

In this work, two different platinum (Pt) counter electrodes have been prepared by spin coating a Pt solution and screen printing a Pt paste on fluorine doped tin oxide (FTO) glass substrate followed by sintering at $380^{\circ}C$ for 30 min. Linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) analyses of the Pt electrodes showed that the spin coated electrode was catalytically more active than the screen printed electrode. The above result agrees well with the surface morphology of the electrodes studied by atomic force microscopy (AFM) and the photovoltaic performance of the dye-sensitized solar cells (DSSCs) fabricated with the Pt electrodes. Moreover, calculation of current density-voltage (j-V) curves according to diode model with the parameters obtained from the experimental j-V curves and the EIS data of the DSSCs provided a quantitative insight about how the catalytic activity of the counter electrodes affected the photovoltaic performance of the cells. Even though the experimental situations involved in this work are trivial, the method of analyses outlined here gives a strong insight about how the catalytic activity of a counter electrode affects the photovoltaic performance of a DSSC. This work, also, demonstrates how the photovoltaic performance of DSSCs can be improved by tuning the performance of counter electrode materials.

• Journal of Periodontal and Implant Science
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• v.27 no.3
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• pp.647-668
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• 1997

6 beagle dogs aged over one and half years and weighed 14 to 16 Kg were utilized in this study, Horizontal furcation defects were induced around 2nd, 3rd, and 4th premolars bilaterally, PDGF-BB in conjunction with EGF and PDGF-BB only were applied in the right and left premolars respectively. 2 animals were sacrificed at 4weeks, 8 weeks, and 12 weeks, after regenerative surgery respectively. Semi-thin sections using glass-knife were stained with toluidine blue for light microscopic study. The results were as follows: 1. At 4 weeks after regenerative surgery, bone formation in the PDGF-BB-applied site was thriving, but bone formation in the PDGF-BB-and-EGF-applied site was depressed. 2. Bony ankylosis was surely shown along the whole exposed root surface applied with PDGF-BB, but it was shown at the root surface near the base of the bone defect where was applied with PDGF-BB in conjunction with EGF. 3. Active bone formation was made from 8 weeks after regenerative surgery in the PDGF-BB- and-EGF-applied site. 4. Bone maturity as well as speed of bone formation in the PDGF-BB-applied site was superior to those in the PDGF-BB-and-EGF-applied site throughout the whole experimental period. Within the above results, PDGF-BB had the strong capability to form the new bone and EGF was not able to prevent the bony ankylosis thoroughly. However, EGF may have the possibility to prevent the bony ankylosis through the suppression of bone formation.