• Journal of environmental and Sanitary engineering
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• v.5 no.2
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• pp.103-110
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• 1990

For production of thermophilic and alkaline protease, Bacillus sp. strain AP-5 was isolated from a compost. The production of the protease was reached at maximum for 4 days at $55^{\circ}$ in standing culture. Chitin and Cellulose as carbon source, and Skim Milk as nitrogen source were favorable for the production of the enzyme. Optimal temperature and optimal pH of the enzyme was $55^{\circ}$ and 11, respectively. Metal ion didn't effect on the enzyme activity, the protease was very stable at heat treatment of 30 min at $55^{\circ}$.

• ETRI Journal
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• v.31 no.2
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• pp.243-245
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• 2009

A novel ultra-low-power readout circuit for a pH-sensitive ion-sensitive field-effect transistor (ISFET) is proposed. It uses an ISFET/reference FET (REFET) differential pair operating in weak-inversion and a simple current-mode metal-oxide semiconductor FET (MOSFET) translinear circuit. Simulation results verify that the circuit operates with excellent common-mode rejection ability and good linearity for a single pH range from 4 to 10, while only 4 nA is drawn from a single 1 V supply voltage.

• YAKHAK HOEJI
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• v.50 no.4
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• pp.228-233
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• 2006

Matrix metalloproteinase-2 is known to be involved in pathological processes such as tumor invasion or rheumatoid arthritis. A soil microorganism producing siderophore under low iron stress $(up\;to\;5\;{\mu}m\;of\;iron)$ was identified as Burkholderia sp. Hydroxamate type siderophore produced by Burkholderia sp. CAS-5 was partially purified. MMP inhibitory activity of siderophore was confirmed by gelatin zymography. The $Zn^{2+}-chelating$ activity of siderophore correlated with the inhibition of MMP-2 activity.

• Carbon letters
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• v.3 no.4
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• pp.219-225
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• 2002

The two-step surface modifications of activated carbon was carried out to improve the adsorption capacity of toxic heavy metal ions in liquid phase. Physical and chemical properties of the as-received activated carbon (AC) and two kinds of surface-modified activated carbons ($1^{st}AC$ and $2^{nd}AC$) were evaluated through the BET analysis, surface acidity, and oxides measurements. Specific surface area and pore volume did not significantly change, but surface oxide-group remarkably increased by the surface modification. Equilibrium and batch adsorptions of the various metals, such as Pb, Cd, and Cr, using AC, $1^{st}AC$, and $2^{nd}AC$ were performed at initial pH 5. The adsorption capacity and rate of $2^{nd}AC$ were higher than those of AC and $1^{st}AC$. The carboxylic/sodium carboxylate complex groups were developed from the two-step surface modification of activated carbon, which strongly affected the adsorption of metal ions.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.09a
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• pp.97-102
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• 1998

Transition metal Cr3+ and Fe3+ ion was diffused in white sapphire {0001}, {1010} crystal plane which were grown by the Verneuil method. It enhanced and changed the physical, electrical and optical properties of sapphires. After mixing the metallic oxide and metal powder, it were used for diffusion. Metallic oxide was synthesized by precipitation method and it's composition was mainly alumina which doped with chromium or ferric oxide. In case using metallic oxide, the dopping was slowly progressed and it needed the longer duration time and higher temperature, relatively. Metallic powder was vapoured under 1x10-4 torr of vacuum pressure at 1900(iron metal) and 2050(chromium)℃, first step. Diffusion condition were kept by 6atm of N2 accelerating pressure at 2050∼2150℃. Each surface density of sapphire crystal are 0.225(c) and 0.1199atom/Å2(a). The color of the Cr-doped sapphires was changed to red. Dopping reaction was come out more deep in th plane of {1010} than {0001}. It was speculated that the planar density was one of the factors to determine diffusion effect.

• Journal of Environmental Health Sciences
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• v.21 no.3
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• pp.87-95
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• 1995

A rapid and selective co-extraction systems of copper and zinc-thiocyanate complex into various types of alkylamine for the simultaneous determination of two metal ions by atomic absorption spectrometry and ion chromatograph have been proposed. The quantitative extractions of Cu(II) and Zn(II) at 0.1 M-thiocyanate and 0.1 M-HCI were achieved with Aliquat 336-$CHCl_3$. The detection limits of Cu and Zn were 2 ppb and 0.9 ppb respectively.

• Journal of the Korean Ceramic Society
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• v.26 no.5
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• pp.601-608
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• 1989

Electrical properties of ZrF4-based heavy metla fluoride glasses were measured by the ac complex impedance method. The effects of alkali and chloride ions addition into fluoro zirconate glasses on the electrical conductivity were examined. The electrical conductivities of fluoride glasses show Arrhenian behavior in the temperature range of the experiment and were decreased by the addition of sodium fluoride up to 15mol%. Mixed alkali substitution resulted in conductivity minimum at intermediate composition which is commonly observed as mixed alkali effect' in alkali oxide glasses. Chloride ion substituted for fluoride ion was found to lower the conductivity.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.170-170
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• 2003

We have implanted on sapphire substrate with various ions and investigated the properties of GaN epilayers grown on implanted sapphire substrate by metal organic chemical vapor deposition (MOCVD). Sapphire is typical substrate for GaN epilayers. However, there are many problems such as lattice mismatch and thermal coefficient difference between sapphire substrate and GaN. The ion implanted substrate's surface had decreased internal tree energies during the growth of the GaN epilayer, md the misfit strain was relieved through the formation of an AlN phase on the ions implanted sapphire(0001) substrates. [1] The crystal and optical properties of GaN epilayer grown in ions implanted sapphire(0001) substrate were improved.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.469-471
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• 1995

This paper describes the effect of floating metallic object on do flashover characteristics in all gap producing unipolar ion flow field. Needle-to-plane electrodes of 120mm in gap length were used as the main gap electrode and the tested metallic objects were spheres with the radius of 2,10 and 15mm or needles from 5 to 40mm long. The characteristics of flashover voltage vs. location of the floating object are different completely with the shape of the floating metal and polarity of the applied voltage.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.361-364
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• 2000

Antimony doped tin oxide (ATO) thin films were deposited at room temperature by reactive ion-beam sputter deposition (IBSD) technique in oxidizing atmosphere utilizing Sb and Sn metal targets. Effect of Sb doping concentration, film thickness and heat treatment on electrical and optical properties was investigated. The thickness of as-deposited films was controlled approximately to 1500 $\AA$ or 2000$\AA$, and Sb concentration to 10.8 and 14.9 wt%, as determined by SEM and XPS analyses. Heat treatment was performed at the temperature from 40$0^{\circ}C$ to 80$0^{\circ}C$ in flowing $O_2$or forming gas. The resulting ATO films showed widely changing electrical resistivity and optical transmittance values in the visible spectrum depending on the composition, thickness and firing condition.