• Journal of Microbiology and Biotechnology
• /
• v.14 no.4
• /
• pp.863-867
• /
• 2004

$\alpha$-Galactosidase from A. oryzae DR-5 was induced in the presence of melibiose, raffinose, galactose, and locust bean galactomannan. The enzyme was purified to homogeneity by precipitation with acetone followed by ion-exchange chromatography using DEAE-Sephacel. The purified enzyme showed a single band in both nondenaturing-PAGE and SDS-PAGE. The enzyme was a glycoprotein in nature by activity staining. The molecular weight of the purified enzyme was 93-95 kDa by SDS-PAGE. The enzyme exhibited the optimum pH and temperature at 4.7 and $60^\circ{C}$, respectively. $\alpha$-Galactosidase activity was strongly inhibited by $Ag^{2+}, Hg^{2+}, Cu^{2+}$, and galactose. EDTA, 1,10-phenanthraline, and PMSF did not inhibit the enzyme activity, whereas N-bromosuccinimide completely inhibited enzyme activity. Investigation by TLC showed complete hydrolysis of stachyose and raffinose in soymilk in 3 h at pH 5.0 and $50^\circ{C}$.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2006.04a
• /
• pp.41-44
• /
• 2006

The objective of this study was to evaluate the stabilization of As and heavy metals in tailings from the Samkwang Au-Ag mine with $Ca(OH)_2$. In order to evaluate the stabilization ability of As and heavy metals in the tailings, column test was implemented with various conditions as 1) particle size of $Ca(OH)_2$, 2) mixing method and 3) flow rate of eluents during 60 days. The results showed that addition with 5% of $Ca(OH)_2$ in 1kg of the tailings had the most effective ability of stabilization up to 95%. In addition, stabilization ability of As and heavy metals in tailings was enhanced using a fine powder of $Ca(OH)_2$. Therefore, stabilization technology can be used as a remediation of As and heavy metals in mine wastes including tailings and a nearby soils from abandoned metal mines.

• The Korean Journal of Food And Nutrition
• /
• v.13 no.2
• /
• pp.176-180
• /
• 2000

Microbial protease has been interesting due to the biological roles in the producing microorganism. A thermophilic Actinomyces produing protease was isolated from soil. The optimal medium composition and culture conditions for maximum protease production was as follows 0.5% soluble starch, 0.5% yeast extract. 0.1% K2HPO4, 0.05% CaCl2, initial pH 8.0 at 50$^{\circ}C$ for 48hours. The protease was purified by the procedure of ammonium sulfate precipitation, anion exchange chromatography(LC), DEAE high performance liquid chromatography and GPC HPLC. The purification fold of the purified enzyme was increased about 22.6. The optimal pH and temperature for reaction of the purified enzyme were 7.5 and 60$^{\circ}C$. The purified enzyme was stable for the pH range from 6.0 to 8.5, but was unstable when treated at 80$^{\circ}C$ for 10 minutes. The activity of the enzyme was inhibited by Ag+ and Cu2+.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1998.06a
• /
• pp.41-44
• /
• 1998

Dual mode resonators were fabricated using high temperature superconductor. The deposited material was $Y_1Ba_2Cu_3O_{7-x}$(YBCO) on MgO(100) substrate using pulsed laser deposition. Dual mode resonators were patterned by standard photolithography process and wet etching. At the back-side of the substrate, the ground plane with the metal layer of Ti and Ag was fabricated. The transition temperatures of YBCO films were 85-88 K, and network analyzer was used for testing the performance of the resonators. The input/output feedline angles of each resonator were $60^{\circ}$and $100^{\circ}$. The resonant frequency of resonators was 10 GHz. In this paper, dual mode resonator was fabricated for the application of satellite communication.

• Proceedings of the KSMRM Conference
• /
• 2002.11a
• /
• pp.114-114
• /
• 2002

Purpose： To know the fate of Gadophrin-2-enhanced areas in hearts with acute reperfused myocardial infarction. Method： The left anterior descending branches of coronary arteries were occluded for 90 min and reperfused for 60 min in 15 rabbits. Then, Gadophrin-2 (0.05 mmol/kg) was injected via ear veins. Short-axial T1-weighted spin echo images and fast cine images were obtained 24 hours after injection of Gadophrin-2. After four weeks, short-axial cine MRI was performed and T1-weighted spin echo Images were obtained 5 min and 15 min after injection of Gd-DTPA (0.2 mmol/kg). The animals were sacrificed and short-axial slices of the specimen were stained with 1.5% triphenyltetrazolium chloride (TTC) solution.

• Proceedings of the KIEE Conference
• /
• 2007.11a
• /
• pp.175-176
• /
• 2007

본 연구에서는 기존의 ITO전극을 사용하지 않는 새로운 전극구조를 가지는 AC-PDP를 제안하였다. 제안한 구조는 상판의 유지전극들을 패터닝된 유전체층 사이에 Ag 전극을 경사형 으로 형성하여 만든 구조이다. 테스트 패널은 각각 $250{\mu}\;300{\mu}m,\;350{\mu}m$의 유지전극 간격들을 가지는 제안된 구조와 기존의 유지전극 간격 $60{\mu}m$의 ITO 구조를 reference로하여 제작하였다. 제안한 구조의 휘도는 방전 갭의 길이에 비례하여 증가하였고 방전전류가 약 $33{\sim}70%$ 감소하여 효율이 유지전극 간격 $300{\mu}m$에서 최대 130% 증가하여 2배이상 증가하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.06a
• /
• pp.58-59
• /
• 2007

We have fabricated top-emission. organic ligth-emitting diodes in a structure of Glass/Al/2-TNATA/TPD/$Alq_3$/LiF/Al/Ag. By varying a film thickness of 2-TNATA and TPD, current efficiency, luminance efficiency, and viewing angle dependence of the device were measured. The top device using $Alq_3$ showed electroluminescent peak wavelengths of 522nm and 505nm at $0^{\circ}$ and $60^{\circ}$ viewing angles, respectively. It is thought that a microcavity effect affects on peak wavelength position for different viewing angles.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.11a
• /
• pp.594-597
• /
• 2003

In the present study, the piezoelectricity and polarization of multilayer ceramic actuator, being designed to stack PMN-PZ-PT ceramic layers and Ag-Pd electrode layers alternatively, were investigated under a consideration of geometric factor, the volume ratio of the ceramic to the electrode layers. The actuators were fabricated by tape casting of 0.2Pb(Mg1/3Nb2/3)O3-0.38PbZrO3-0.42PbTiO3 followed by lamination and burnout & co-firing processes. The actuators of 10 10 0.62 nm3 in size were formed in a way that 60 200 m thick ceramics were stacked alternatively with 5 m thick electrode layer. Increases in polarization and electric field-induced displacement with thickness of the ceramic layer were attributed to change of 90o/180o domain ratio, which was affected by interlayer internal stress. The piezoelectricity and actuation behaviors were found to depend upon the volume ratio (or thickness ratio) of ceramic to electrode layers.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.06a
• /
• pp.559-560
• /
• 2006

Inkjet Printing is very attractive method for direct patterns with no masks, In order to Achieve direct printing with nano metal, It is often necessary to print them with highly concentrated Ink We research the High Concentrated silver nano ink. Formulation which has a good thermal stability and storage stability and jet stability using a ethylene glycol ether. Normally Alcohol-based inks can be sensitive But High boiling point ethylene glycol ether base Ink is creating a stable meniscus and minimum maintenance issues. We are reaching a 50~60wt% high Silver Ink using a Hydrophilic Ag Nano powder. (30~50nm)

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.06a
• /
• pp.551-552
• /
• 2006

This study was attended to demonstrate synthesis of silver nanoparticles stabilized with polymer and their applicability to printed electronics. Silver nanoparticles were synthesized by reduction of silver nitrate in aqueous solution in the presence of polyvinyl pyrrolidone (PVP) as a stabilizer. The ink used here is composed of 50 wt% Ag NP, 15 wt% humectant and then were printed on polyimide film. Particle deposit morphologies were controlled by varying the ink compositions. Printed silver patterns and dots were cured on a convection oven in air at $300^{\circ}C$ for 60 min. The printed patterns show good shape definition and the resistivity of the printed films is about $5{\mu}{\Omega}{\cdot}cm$.