• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.4
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• pp.371-377
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• 2008

Our precedent study has reported glass-PDMS (polydimethylsiloxane) based biochip for the gene PCR (polymerase chain reaction). To prevent the contamination of bio sample, the once used biochip must not be used repeatedly. However, the fabrication cost of microheater and microsensor of the biochip was not cheap to use it as a disposable chip. This paper proposes new PCR-chip where the glass substrate integrated with the microheater and microsensor is detachable from the reaction chamber where the sample is injected. That makes it possible to reuse the glass substrate repeatedly. The performance of the proposed detachable PCR-chip was compared with that of the precedent monolithic PCR-chip. The results showed that the SRY (sex determining Y chromosome) gene PCR was successfully performed in the detachable chip compared with the monolithic chip. However, the more efforts to improve the efficiency of surface treatment of PDMS chip are needed to increase the possibility of applying the detachable chip to the detecting of male infertility.

• Journal of Korean Society of Water and Wastewater
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• v.13 no.4
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• pp.35-44
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• 1999

In this study, it was attempted to remove nitrate and carbon in a single-stage reactor using acetate as substrate. Hybrid type upflow sludge baffled filter reactor was adopted using anaerobic sludge. Sludge bed in the bottom of reactor was intended to remove carbon and nitrate by denitrification and methanogenesis. And floating media in the upper part of reactor were intended to remove remaining carbon which was not removed due to the inhibition of nitrogen oxide on methane producing bacteria. The reactor removed over 96% of COD and most of nitrate with volumetric loading rate of $4.0kgCOD/m^3{\cdot}day$, hydraulic retention time of 24hr, 4,000mgCOD/L, and $266mgNO_3-N/L$. Nitrate in anaerobic sludge was converted to nitrogen gas(denitrification) or ammonia (ammonification) according to pH of influent, COD removal efficiency was easily affected by the change of volumetric loading rates and nitrate concentration. And when influent pH was about 4.7, most nitrate changed to ammonia while when influent pH was about 6.8~7.0, most nitrate denitrified independent of $COD/NO_3-N$ ratio. Most granules were gray and a few were black. In gray-colored granule, black inner side was covered with gray substance and SEM illustrated Methanoccoci type microorganisms which were compact spherical shape. Anaerobic filter removed residual COD effectively which was left in sludge bed due to the inhibition of nitrogen oxide.

• Journal of Korean Society of Water and Wastewater
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• v.13 no.4
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• pp.45-53
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• 1999

The microbial organisms named "Pseudomonas sp. LK-14" were isolated from farm land and shallow river sediment, activated, augmented and identified; which were using 2,4-D (2,4-Dichlorophenoxyacetic acid) as a sole carbon source and energy source. 2,4-D removal efficiency of LK-14 with 2,4-D sole carbon source (reactor S) were higher than that of Activated Sludge with 2,4-D sole carbon source (reactor A). Dynamic bioligical reaction kinetic parameters (sole carbon source was 2,4-D) obtained from batch reactor experiments were ${\mu}_{max}$ $0.105hr^{-1}$, $K_{s,24D}$ 15.64mg/L, $K_{i,24D}$ $1.94h^{r-1}$, $Y_{24D}$ 0.39 for LK-14 and ${\mu}_{max}$ $0.008hr^{-1}$, $K_{s,24D}$ 26.95mg/L, $K_{i,24D}$ $1.75hr^{-1}$, $Y_{24D}$ 0.10 for Activated Sludge. Using these parameters, we could predict the behaviors of 2,4-D substrate utilized by LK-14 and Activated Sludge in batch reactors. The kinetic parameters are enable to predict the 2,4-D substrate and microbial population behavior entering into wastewater treatment plants by using unsteady states dynamic simulation modeling technique.

• Current Photovoltaic Research
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• v.6 no.2
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• pp.56-61
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• 2018

In this study, CIGS absorber layers were deposited on low-alkali glass and sodalime glass substrates and potasium floride (KF) of various thicknesses was supplied at an elevated temperature after the CIGS growth. The effect of KF post-deposition treatment on the two types of substrates was extremely different. On the low-alkali substrate, the open-circuit voltage (Voc) was improved but the fill-factor (FF) degradation was severe, whereas the sodalime substrate showed Voc deterioration and FF improvement. In the case of supplying 20 nm of KF on both substrates, the efficiency gain of 0.3~1.1%p was obtained. With increasing the KF thickness, a small protrusion-like microstructure developed on the surface of the absorber layer, and the microstructures that were not removed in the subsequent process were found to be the main cause of the FF loss.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.6
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• pp.280-284
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• 2015

Au doped $TiO_2$ nanoparticles have been synthesized using a reverse micelle technique combined with metal alkoxide hydrolysis and condensation. Au doped $TiO_2$ was coated with glass substrate. The size of the particles and thickness of the coating can be controlled by manipulating the relative rates of the hydrolysis and condensation reaction of TTIP within the micro-emulsion. The average size of synthesized Au doped $TiO_2$ nanoparticle was about in the size range of 15 to 25 nm and the Au particles formed mainly the range of 2 to 10 nm in diameter. The effect of synthesis parameters, such as the molar ratio of water to TTIP and the molar ratio of water to surfactant, are discussed. The synthesized nanopaticles were coated on glass substrate by a spin coating process. The thickness of thin film was about 80 nm. The degradation of MB on a $TiO_2$ thin film was enhanced over 20 % efficiency by the incorporation of Au.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.9
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• pp.1264-1276
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• 2000

Light-off catalyst has been used for minimization of cold-start emissions. Improved cold-start performance of light-off catalyst needs the optimal design in terms of flow distribution, geometric surface area, precious metal loading, cell density and space velocity. In this study, these influential factors are numerically investigated using integrated numerical technique by considering not only 3-D fluid flow but also heat and mass transfer with chemical reactions. The present results indicate that uneven catalyst loading of depositing high active catalyst at upstream of monolith is beneficial during warm-up period but its effect is severely deteriorated when the space velocity is above 100,000 $hr^{-1}$ To maximize light-off performance, this study suggests that 1) a light-off catalyst be designed double substrate type; 2) the substrate with high GSA and high PM loading at face be placed at the front monolith; and 3) the cell density of the rear monolith be lower to reduce the pressure drop.

• KSBB Journal
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• v.23 no.3
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• pp.187-192
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• 2008

Lysozyme-producing microorganisms were isolated to obtain bacteria which can efficiently solubilize microbial cells. Cells of normal and chloroform-treated Escherichia coli and Micrococcus Iysodeikticus were used as model substrates to isolate lysozyme-producing microorganisms and investigate the efficiency of cell lysis. The culture supernatant of the isolate New1 (98% similarity of 16S rDNA sequence with Thermomonas haemolytica) showed different lytic characteristics for different substrates. Thermal treatment (autoclave) of substrate cells showed a significant effect on cell solubilization by culture supernatant of the New1. For autoclaved substrate cells, E. coli, M. Iysodeikticus and chloroform-treated E. coli were solubilized by 58.7%, 49.4% and 79.1%, respectively, in the culture supernatant of New1. The lytic activity of New1 was mainly caused by lysozyme produced by the isolate. It was also showed that New1 exhibited high protease activity and a little cellulase activity.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.3
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• pp.307-314
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• 2009

Large area micro pattern replication has promising application potential in many areas. Rolling imprint process has been demonstrated as one of the most competitive processes for such micro pattern replication, because it has advantages in low cost, high throughput and high efficiency. In this paper, we developed a prototype of roll-to-flat(R2F) thermal imprint system for large area micro pattern replication process, which is one of the key processes in the fabrication of flexible displays. Experimental tests were conducted to evaluate the feasibility of system and the parameters' effect on the process, such as flat mold temperature, loading pressure and rolling speed. 100mm $\times$ 100mm stainless steel flat mold and commercially available polycarbonate sheets were used for the tests. The experimental results showed that the developed R2F system is suitable for fabrication of various micro devices with micro pattern over large area.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.5
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• pp.63-71
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• 2007

The conversion efficiency, durability and pressure drop of the automotive exhaust catalysts are dependent on the flow distribution within the substrate. Conventional porous medium approaches assuming monolith resistance based on the one-dimensional laminar flow for simulating the flow through the automotive exhaust catalysts over-predict the flow uniformity in the monolith. In this study, additional pressure loss is also considered by accounting for entrance effects due to the oblique flow incident on the front face of monolith as a consequence of flow separation and recirculation within the diffuser. The incorporation of an additional pressure loss improves the predictions for the maximum flow velocity within the substrate. An numerical study has also been conducted for the three-dimensional unsteady incompressible non-reacting flow inside various dual-monolith catalytic converters for the rapid acceleration/deceleration driving.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.3
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• pp.14-19
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• 2010

Partial anodic oxidation of Ti-mesh with a wire diameter of ~200[${\mu}m$] produces self-aligned $TiO_2$ nanotube arrays (~50[${\mu}m$] in length) on Ti-mesh substrate. The electrolyte used for anodic oxidation was an ethylene glycol solution with an addition of 1.5 vol. % $H_2O$ and 0.2 wt. % $NH_4F$. A dye-sensitized solar cell utilizing the photoanode structure of $TiO_2$-nanotube/Ti-mesh was fabricated without a transparent conducting oxide (TCO) layer, in which Ti-mesh replaced the role of TCO. The 1.93[%] photoconversion efficiency was low, which can be attributed to both insufficient dye molecules attachment and limited electrolyte flow to dye molecules. The optimized nanotube diameter and length as well as the $TiCl_4$ treatment can improve cell performance.