• Microbiology and Biotechnology Letters
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• v.20 no.5
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• pp.534-542
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• 1992

Trypsin inhibtor produced by Streptomyces sp. S-217 was purified by solvent extraction and various column chromatographies. and physico-chemical properties of the inhibitor were investigated. Inhibitor complex was formed for incubation of 10 min. Streptomyces 5-217 showed the highest production of trypsin inhibitor when it was cultivated at $37^{\circ}C$ for 66 hr in the medium containing 2% mannitol & 0.9% peptone, pH 7.0. Trypsin inhibitor was purified by column chromatography and high performance liquid chromatography. Trypsin inhibitor indicated the maxium wavelength at 215 nm and solubilities in water, methanol and dimethyl sulfoxide were 95, 70 and 75%, respectively. The concentration of 50% inhibition ($IC^{50}$) was 15 $\mu$g/ml. The inhibitor was stable on heating at $100^{\circ}C$ for 60 min in pH 5~9 and was more stable in alkaline region than acidic region.

• Journal of the Korean Magnetics Society
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• v.18 no.2
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• pp.49-53
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• 2008

Magnetic and crystallographic properties of patterned media fabricated by nanoimprint lithography and Co-Pt electroplating were studied. Thin films of Ru(20 nm)/Ta(5 nm)/$SiO_2$(100 nm) were deposited on Si(100) wafer and then 25 nm hole pattern was fabricated by nanoimprint lithography on substrate. The electroplated Co-Pt nano-dots have the diameter of 35 nm and the height of 27 nm. Magnetic dot patterns of Co-Pt alloy were created using electroplated Co-Pt alloy and then their properties were measured by MFM, SQUID, SEM, TEM and AFM. We observed single domain with perendicular anisotropy for each dot and achieved optimum coercivity of 2900 Oe. These results mean that patterned media fabricated by nanoimprint lithography and electroplating have good properties in view of extending superparamagnetic limit while satisfying the writability requirements with the present write heads.

• Journal of Sensor Science and Technology
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• v.6 no.1
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• pp.24-34
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• 1997

In this study, two different types of complementary electrochromic devices using amorphous $WO_{3}$ films as a working electrode, $V_{2}O_{5}$ film and NiO film as counter electrodes respectively were investigated. For the devices using amorphous and crystalline $V_{2}O_{5}$ films of $100{\sim}150nm$ thickness with $ITO/WO_{3}/LiClO_{4}-PC/V_{2}O_{5}/ITO$ structure, an optical modulation of $50{\sim}60%$ were obtained at a potential range of $1{\sim}2V$. It has been shown that transmittance and reflectance of light could be electrically controlled by low applied voltage. For the devices with $ITO/WO_{3}/LiClO_{4}-PC/NiO/ITO$ structure in which NiO film was deposited by a RF reactive sputtering, the optical modulation in visible light region (${\lambda}=550nm$) and in near infrared light region (${\lambda}=850nm$) were 25% and 30%, respectively.

• Journal of the Microelectronics and Packaging Society
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• v.22 no.3
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• pp.25-30
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• 2015

SAC-coated Cu specimens were fabricated by novel pad finish process using a phenomenon that metal nanoparticles less than 20 nm in diameter melted at a temperature lower than the melting point of bulk metal, and their wettabilities were evaluated. The thickness of SAC305 layer coated at low temperature of $160^{\circ}C$ using SAC305 ink was extremely thin as the level of several nanometers. It was analyzed by Auger electron spectroscopy that $Cu_6Sn_5$ intermetallic layer with a thickness of 10~100 nm and $Cu_3Sn$ intermetallic layer with a thickness of 50~150 nm were sequentially formed under the SAC305 coating layer. The thickness of formed intermetallic layers was thicker in electroplated Cu than rolled Cu, which attributed to improved surface roughness in the electroplated Cu. The improved surface roughness induces the contact, melting, and reaction of a larger number of SAC305 nanoparticles per the unit area of Cu specimen. In the wetting angle test using SAC305 solder balls, the Cu coated with SAC305 through the low temperature process presented evidently low wetting angles than those in non-coated Cu, indicating that only a few nanometer-thick SAC305 coating layer on Cu could also cause the enhancement of wettability.

• Applied Chemistry for Engineering
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• v.17 no.4
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• pp.420-425
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• 2006

Nano sized mixed metal hexagonal ferrite powders with improved magnetic properties have been prepared by sol-gel method using propylene oxide as a gelation agent. To obtain the desired ferrite, two different metal ions were used. One of the ions has only +2 formal charge. The key step in the processes is that hydrated $Ba^{2+}$ or $Sr^{2+}$ ions are hydrolyzed and condensed at the surface of the previously formed $Fe_{2}O_{3}$ gel. In this processes, all the reaction can be finished within a few minutes. The magnetic properties of the produced powder were improved by heat treatment. The highest values of the magnetic properties were achieved at temperature $150^{\circ}C$ lower than those of the previously published values. The highest observed values of coercivity and the saturation magnetization of Sr-ferrite and Ba-ferrite powder were 6198 Oe, 5155 Oe and 74.4 emu/g, 68.1 emu/g, respectively. The ferrite powder annealed at $700^{\circ}C$ showed spherical particle shapes. The resulting spheres which were formed by the aggregation of nanoparticles with size 3~5 nm have diameter around 50 nm. The powder treated at $800^{\circ}C$ showed hexagonal-shaped grains with crystallite size above 500 nm.

• Applied Chemistry for Engineering
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• v.19 no.1
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• pp.37-44
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• 2008

The multi-layer PET film of ITO/ATO was prepared by a wet coating method to obtain the transparent film with a high conductance at low cost. ITO nano-particles were synthesized by a SAS method at 15 MPa and $50^{\circ}C$, where optimized rate of In/Sn was 65. Average diameter and resistivity of ITO obtained from SAS are $15{\pm}2nm$ and $4{\times}10^4{\Omega}{\cdot}cm$. Coating solution was prepared at pH 10. Roughness (Ra), resistivity, and transmissivity of ATO film on PET are 9 nm, $5.5{\times}10^6{\Omega}{\cdot}cm$, and 91%. The multi-layered film of ITO/ATO was obtained by solution including 0.1, 0.5, 1.0, and 2.0 ITO wt% on ATO layer. Roughness (Ra) of multi-layered film with 0.1, 0.5, 1.0, and 2.0 ITO wt% is 4, 10, 12, and 16 nm, respectively. Corresponding resistivity with an increasing ITO concentration is $3.7{\times}10^6$, $2.4{\times}10^6$, $8{\times}10^5$, and $2{\times}10^5{\Omega}{\cdot}cm$. Transmissivity of ITO/ATO film decreases as 89, 88, 86, and 82% with an increasing ITO concentration as 0.1, 0.5, 1.0, and 2.0 wt%.

• Journal of Conservation Science
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• v.32 no.3
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• pp.377-384
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• 2016

There are physical and chemical method for removement of a lacquered layer existing on the surface when gilding an iron Buddha, these caused environmental pollution by surface degradation and is very noxious for conservation scientist's health. Thus, on this study, we conducted a lacquered layer removement experiments using Nd:YAG Laser which is contactless and eco-friendly. Specimens were made by polishing $5{\times}5$ size of iron(99.9%) specimens surfaces evenly and by differing of number of coating of unrefined lacquer, so there were thickness differences of $10{\mu}m$, $20{\mu}m$, and $30{\mu}m$. The laser machine used in this study was Nd:YAG Laser, and we used two wavelength modes; 1064 nm(160~180 mJ) for infrared light region and 532 nm(50~350 mJ) for ultraviolet light region. The experiment done by investigating the transition of specimens' surfaces with laser wavelength, energy, and numbers of investigation. The remain amount of lacquered layer surfaces before/after laser irradiation was investigated by stereoscopic microscope, observation by SEM, Non-contact Surface Roughness Measurement Device, and FT-IR etc. As a result of each analysis, we could verify the thickness of $10{\mu}m$, $20{\mu}m$ of lacquered layer removed without surface degradation when using 1064 nm wavelength with $1.0J/cm^2$ density. We could find out that Nd:YAG Laser is effective for removing remained lacquered layers when gilding an iron Buddha. In the future, when not only the metal has made various studies also wood lacquered furniture or the like, it seems to be utilized to remove the lacquer without surface damage.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.12
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• pp.6187-6195
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• 2012

Recycling process of iron should be developed for efficient recovery of neodymium(Nd), rare metal, from acid-leaching solution of neodymium magnet. In this study, $FeCl_3$ solution as iron source was used for synthesis of iron nanoparticle with the condition of various factors, etc, reductant, surfactant. $Na_4O_7P_2$ and polyvinylpyrrolidone(PVP) as surfactants, $NaBH_4$ as reductant, and palladium chloride($PdCl_2$) as a nucleation seed were used. Iron powder was analyzed with instruments of XRD, SEM and PSA for measuring shape and size. Iron nanoparticles were made at the ratio of 1 : 5(Fe (III) : $NaBH_4$) after 30 min of reduction time. Size and shape of iron particles synthesized were round-form and 50 nm ~ 100 nm size. Zeta-potential of iron at the 100 mg/L of $Na_4O_7P_2$ was negative value, which is good for dispersion of metal particle. When $Na_4O_7P_2$(100 mg/L), PVP($FeCl_3$ : PVP = 1 : 4, w/w) and Pd($FeCl_3$ : $PdCl_2$ = 1 : 0.001, w/w) were used, iron nanoparticles which are round-shape, well-dispersed, near 100 nm-sized can be made.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.4
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• pp.409-416
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• 2011

A mobile emission laboratory (MEL) was designed to measure the amount of traffic pollutants with high temporal and spatial resolution under real conditions. Equipment for gas-phase measurements of quantity of CO, NOx, $CO_2$, and THC and for the measurement of the number density and size distribution of fine and ultra-fine particles by a FMPS and a CPC were placed in a mini-van. The exhaust of different type of vehicles can be sampled by MEL. This paper describes the construction and technical details of the MEL and presents data from the experiment in which a car chases city buses fuelled by diesel, CNG, and LPG. The diameters of most particles in the exhaust of the diesel city bus were less than 300 nm and most of the particles had a diameter of 30-60 nm. However, most particles in the exhaust of the CNG and LPG city buses were nanoparticles (diameter: less than 50 nm).

• Journal of Animal Environmental Science
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• v.9 no.2
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• pp.85-92
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• 2003

These experiments were conducted to evaluate the efficiency of the color removal treatment system of pig wastewater by $TiO_2$. The results obtained are summarized as follow ： 1 The color removal efficiency of effluent of activated sludge process by $TiO_2$ level were 59.7 and 52.5% for 1.0 and 2.0g/$\ell$ at 360 minute of operation time, respectively. 2. The color of pig wastewater was changed from 655 color unit(cu) to 146cu of the wastewater treatment of pH 5 at 300 minute of operation time. 3. The $H_2O_2$ level for color removal showed at 200mg/$\ell$ and in that level, the color removal efficiency was 52.5%. 4. The color removal efficiency of 365nm UV intensity was 29.4%, but 254nm of UV intensity was higher(50.1%) than 365nm for color removal.