• KSBB Journal
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• v.14 no.6
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• pp.731-736
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• 1999

87 microbes were isolated from dyeing wastewater collected at Dongducheon and Banweol industrial complex. Five microbes showed excellent ability of color removal and were identified as Shewanella putrefaciens, Aeromonas salmonicida(3 different strains), and Pseudomonas vesicularis. Five identified strains had optimal pH and optimal temperature as 7.0 and 30$^{\circ}C$ for cultivation, and showed morphological characteristics of Gram negative, oxidase negative, rod shape, and non-motility, but their biochemical characteristics were distinguishable. Each single strain of five microbes were tested in the 500 mL flask to treat dyeing wastewater, and achieved about 35% color removal efficiency in average. When two strains were selected and applied to the treatment at same time, color removal efficiency was increased up to 65%. While three or more associations of each strain did not show the improvement of color removal. Inhibition effects by $Mn^{2+}\;and\;Fe^{3+}$ on the dye degradation were tested and resulted in no effect under 70 ppm concentration.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.120-120
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• 2008

We demonstrate epitaxial growth of ZnO thin films on 4H-SiC(0001) substrates using pulsed laser deposition (PLD). ZnO and SiC have attracted attention for their special material properties as wide band gap semiconductors. Especially, ZnO could be applied to optoelectronic applications such as light emitting devices and photo detectors due to its direct wide bandgap (Eg) of ~3.37eV and large exciton binding energy of ~60meV. SiC shows a good lattice matching to ZnO compared with other commonly used substrates and in this regard SiC is a good candidate as a substrate for ZnO. In this work, ZnO thin films were grown on 4H-SiC(0001) substrates by PLD using an Nd:YAG laser with a 355nm wavelength. The crystalline properties of the films were evaluated by x-ray diffraction (XRD) $\theta-2\theta$, rocking curve and pole figure measurements using a high-resolution diffractometer. The surface morphology of the films was studied by atomic force microscopy (AFM).

• Journal of Mushroom
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• v.2 no.2
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• pp.60-68
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• 2004

Potato dextrose broth was the best inoculation medium to produce in vitro synnemata of Paecilomyces tenuipes. The optimum temperature for synnemata formation of P. tenuipes was $20^{\circ}C$ under 500 lx of light intensity. Highest synnemata production was observed at 18 hr of light period per day. The medium containing 50 g of each silkworm pupae and brown rice produced highest number of synnemata. The optimum ratio of brown rice to distilled water was found as 1:1. Mycelial growth and synnemata production of P. tenuipes was faster and higher in medium containing grinded pupae as compared to whole pupae. The optimum inoculum amount per bottle of medium was 15ml. The highest synnemata production of P. tenuipes was obtained by incubating rice pupae medium at $24^{\circ}C$ until mycelium grows sufficiently after inoculation and then transferring it to $20^{\circ}C$ chamber till harvest.

• Applied Chemistry for Engineering
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• v.8 no.1
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• pp.76-83
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• 1997

Blends of thermotropic liquid crystalline polymer(TLCP) with poly(ethylene terephthalate) (PET) were prepared by the coprecipitation from a common solvent. The blends were processed through a capillary die at $287^{\circ}C$ to produce a monofilament. Morphology and mechanical, thermal properties of blends and composites were examined by differential scanning calorimetry(DSC), tensile test, optical microscopy and scanning electron microscopy. Crystallization kinetics of the blends were investigated by the isothermal DSC method. The Avrami analyses were applied to obtain the information on the crystal growth geometry and factors controlling the rate of crystallization. In the blends, liquid crystalline phase did not reveal any significant macrophase separation and thermal degradation at the processing temperature. From scanning electron micrographs of cryogenic fracture surfaces of extruded fibers, the TLCP domains were found to be more or less finely dispersed with $0.1{\mu}m$ to $0.2{\mu}m$ in size. Interfacial adhesion between the TLCP and matrix polymer was excellent. Tensile strength and modulus of TLCP/PET in-situ fiber composites were enhanced with increasing draw ratio and LCP content.

• Applied Chemistry for Engineering
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• v.7 no.1
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• pp.34-42
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• 1996

Growth of synthetic emerald [($(BeO)_3(Al_{2-x}Cr_xO_3)(SiO_2)_6$] single crystals was carried out by flux method. In this study, the starting materials were prepared by stoichiometric mixing of BeO, $Al_2O_3$ and $SiO_2$ as reaching components. The conditions for the growth of synthetic emerald single crystals are as follows : temperature range ; $1150{\sim}900^{\circ}C$, cooling rate ; 2, 4, $10^{\circ}C/hr$, flux ; $Li_2CO_3$, $V_2O_5$, dopant ; $Cr_2O_3$. The sizes of $Cr_2O_3$emerald single crystals depending on 2, 4, $10^{\circ}C/hr$ cooling rates. The obtained emerald single crystal was characterized and the following results were obtained : lattice parameter : a=0.921nm, c=0.917nm, crystal system ; hexagonal, crystal size ; max. $0.80{\times}0.95mm^2(c{\times}m)$, orientation ; (1000), $m(10{\bar{1}}0)$.

• Applied Chemistry for Engineering
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• v.24 no.5
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• pp.562-565
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• 2013

The high purity Al foil, which has an enlarged surface area by electrochemical etching process, has been used as an anode for an aluminum electrolytic capacitor. Etch pits are randomly distributed on the surface because of the existence of surface irregularities such as impurity and random nucleation of pits. Even though a large surface area was formed on the tunnel-etched Al, its applications to various fields were limited due to non-uniform tunnel morphologies. In this work, the selective electrochemical etching of aluminum was carried out by using a patterned mask fabricated by photolithographic method. The formation of etch pits with uniform distribution has been demonstrated by the optimization of experimental conditions such as current density and etching solution temperature.

• Journal of Plant Biology
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• v.35 no.4
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• pp.393-401
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• 1992

A new species of Dictyostelium, isolated from the subalpine coniferous forests of Halla mountain, was described. The most noteworthy morphological characteristics of this new species were broad petal-like aggregates, concentrated long branches near the bases, typically clustered and delicate sorocarps. DictyosLeLium jloridurn sp. novo was also characterized by 1) elliptical spores with distinctive polar granules, 2) strongly tapering and rough surface of sorophores, 3) frequent occurrence of expanded conical bases, 4) the congealed slime substrate where the several bases were anchored into, 5) compound and c1avata tips. It was quite sensitive to environmental conditions, particularly temperature. Macrocysts and microcysts were not observed. This species can be cultured satisfactorily in assosiation with Esch'||'&'||'pound;richia coLi upon agar media of weak nutrient content, 0_1% lactosepeptone, under diffuse light and darkness. Optimum temperature for growth and develoi)ment was about $18-22^{\circ}C$, below that of most other species of the family.

• Applied Chemistry for Engineering
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• v.30 no.6
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• pp.659-666
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• 2019

Proton exchange membrane fuel cells (PEMFCs) generate electricity by electrochemical reactions of hydrogen and oxygen. PEMFCs are expected to alternate electric power generator using fossil fuels with various advantages of high power density, low operating temperature, and environmental-friendly products. PEMFCs have widely been used in a number of applications such as fuel cell vehicles (FCVs) and stationary fuel cell systems. However, there are remaining technical issues, particularly the long-term durability of each part of fuel cells. Degradation of a carbon supported-platinum catalyst in the anode and cathode follows various mechanistic origins in different fuel cell operating conditions, and thus accelerated stress test (AST) is suggested to evaluate the durability of electrocatalyst. In this article, comparable protocols of the AST durability test are intensively explained.

• Journal of Sensor Science and Technology
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• v.1 no.1
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• pp.53-57
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• 1992

We report the crystal growth and the electro-optic characteristics of $CdS_{1-x}Se_{x}$ thin films. $CdS_{1-x}Se_{x}$ thin films wire deposited on the alumina plate by electron beam evaporation technique in pressure of $1.5{\times}10^{-7}$ torr, voltage of 4kV, current of 2.5mA and substrate temperature of $300^{\circ}C$. The deposited $CdS_{1-x}Se_{x}$ thin films were proved to be a polycrystal with hexagonal structure through X-ray diffraction patterns. $CdS_{1-x}Se_{x}$ photoconductive films showed high photoconductivity after annealing at $550^{\circ}C$ for 30 minutes. And the films have been investigated the Hall effect, photocurrent spectra, sensitivity, maximum allowable power dissipation and response time.

• Journal of the Microelectronics and Packaging Society
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• v.15 no.4
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• pp.1-7
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• 2008

We studied a growth behavior of Intermetallic compounds(IMCs) during solder bumping with two reflow methods. Ti(50 nm), Cu($1{\mu}m$), Au(50 nm) and Ti(50 nm) thin films were deposited on $SiO_2$/Si wafer using the DC magnetron sputtering system as the under bump metallization(UBM). And the $5{\mu}m$ thick Cu bumps and $20{\mu}m$ thick Sn bumps were fabricated on UBM by electroplating. Sn bumps were reflowed in RTA(Rapid Thermal Annealing) system and convection reflow oven. When RTA system was used, reflow was possible without using flux and IMC thickness formed in the solder interface was thinner than that of a convectional method.