• The KSFM Journal of Fluid Machinery
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• v.17 no.6
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• pp.69-73
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• 2014

To predict flow fields and chemical agent dispersion in urban area, wind tunnel experiments was performed. The agent was adopted MS (methyl salicylate) because the real chemical agent is unsafe. The exact concentration of methyl salicylate was generated by the commercial gas generator (STI-2500) and three different obstacle shapes were applied (i.e., rectangular, cylinder and pyramid). The concentration was measured with the qualified ion mobility sensor and gas chromatography. The data necessary for virtual test method of the real chemical agent were obtained.

• Journal of the Korean Ceramic Society
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• v.48 no.6
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• pp.577-583
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• 2011

Stabilized biocompatible superparamagnetic iron oxide nanoparticles (SPIONs) were prepared by controlled coprecipitation method for hyperthermia application. ESR measurements determined that all of the interactions in the individual SPIONs (1 nm and 11 nm) were antiferromagnetic in nature because the ions contributed to the magnetization with a range of magnetic moments. In-situ monitoring of the temperature increment was performed, showing that the microwave absorption rate of the SPIONs was dispersed in an appropriate host media (polar or non-polar solvents) during microwave irradiation. Microwave absorption energy rates and heat loss of SPIONs in solvent were calculated by non-linear data fitting with an energy balance equation. The microwave absorption rates of SPIONs dispersed in solvent linearly increases when the concentration of SPIONs increases, implying that the microwave absorption rate can be tunable by changing the concentration of SPIONs.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.405-410
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• 2001

Bioremediation is a degradation process of existing organic contaminants in soils and groundwater by indigenous or inoculated microorganisms. This process can provide economical solution as well as safe and effective alternative in remediation technologies. However, it has been suggested that the rate of bioremediation process of organic contaminants by microorganisms can be limited by the concentration of nutrients and TEAs(Terminal Electron Accepters). In in-situ bioremediation, conventional pumping techniques have been used for supplying these additives. However, the injection of these additives is difficult in low permeable soils, and also hindered by preferential flow paths resulting from heterogeneities in high permeable ground. Therefore, the Injection of chemical additives is the most significant concern in in-situ bioremediation. Most recently, electrokinetic technique has been applied into the bioremediation and the injection characteristics under electrokinetics have not been examined in various soil types. Therefore, in this study, electrokinetic injection method is investigated in kaolinite and sand, and the concentration of ammonium(nutrients) and sulfate(TEAs) in soil is presented.

• Journal of Surface Science and Engineering
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• v.41 no.6
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• pp.279-286
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• 2008

Numerical analysis is done to investigate which would be the most influencing process parameter in determining the uniformity of deposition thickness in TiN ICP-CVD(inductively coupled plasma chemical vapor deposition). Two configurations of ICP antenna are modeled; side and top planar. Side and top gas inlets are considered with each ICP antenna geometries. Precursor for TiN deposition was TDMAT(Tetrakis Diethyl Methyl Amido Titanium). Two step volume dissociation of TDMAT is used and absorption, desorption and deposition surface reactions are included. Most influencing factors are H and N concentration dissociated by electron impact collisions in plasma volume which depends on the relative positions of gas inlet and ICP antenna generated hot plasma region. Low surface recombination of N shows hollow type concentration, but H gives a bell type distribution. Film thickness at substrate edges is sensitive to gas flow rate and at high pressures getting more dependent on flow characteristics.

• Journal of Sensor Science and Technology
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• v.16 no.4
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• pp.307-312
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• 2007

The films of Er-doped ZnO (ZnO:Er) were prepared onto MgO wafers by ultrasonic spray pyrolysis at $550^{\circ}C$. The concentration of Er in the deposition source varied from 0.5 wt% to 3.0 wt%. The crystallographic properties and surface morphologies of the films were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. The properties of photoluminescence (PL) for the films were investigated by dependence of PL spectra on the Er concentration in the films. The films were grown as polycrystalline with a dominant direction of [002]. The grain size of the films were reduced by Er-doping. Er-doping enhanced the ultraviolet emission of ZnO:Er films. The ZnO:Er films prepared with the deposition source of 2.0 wt% Er showed the strongest ultraviolet light emission peak among the films in this study.

• Journal of Sericultural and Entomological Science
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• v.40 no.2
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• pp.163-168
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• 1998

Hydrolysis rate and activation energy of Antheraea pernyi silk fiber treated with HCI were examined. Thermal decomposition temperature and surface morphology were also investigated by using differential scanning calorimeter and scanning electron microscope. As the concentration of hydrochloric acid and the treatment temperature increased, the hydrolysis occurred more rapidly. The activation energy of Antheraea pernyi, 74.0 kJ/mol, was higher than that of Bombyx mori, 58.1 kJ/mol. As the concentration of hydrochloric acid increases, the activation energy of Antheraea pernyi decreased from 74.0 kJ/mol to 62.0 kJ/mol. The shape of acid-resistance fraction of Antheraea pernyi became more distroyed and was transformed from fiber to powdered form with an increase of hydrolysis rate. The thermal decomposition temperature of Antheraea pernyi was 360.8$^{\circ}C$ until the hydrolysis rate was 81.8 wt%, but ti decreased to 347.0$^{\circ}C$ when the hydrolysis rate was 93.8 wt%.

• Textile Coloration and Finishing
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• v.24 no.1
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• pp.62-68
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• 2012

Cellulose was electrospun over water collector and the cellulose solution was prepared using N-methyl-morpholine N-oxide/water(nNMMO/$H_2O$). The morphology of electrospun cellulose was investigated by scanning electron microscopy (SEM). SEM images showed that the fiber formation depended on processing parameters such as solution concentration, applied electric field strength, solution feeding rate and temperature of water in coagulation bath. High concentration, low temperature of water bath, and low feeding rate were more favorable to obtain fiber morphology. All the variables affected on the fluidity of the cellulose solution and diffusion of NMMO. Low fluidity and fast diffuision of NMMO was critical for obtaining fiber morphology.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.11a
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• pp.344-345
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• 2015

Various concentration of copper was dopped in Fe-35%Ni thin sheet by electroforming and their electromagnetic, surface properties were determined. Microstructure observation by scanning electron microscopy revealed that the thin sheet had columnar grains with about 150 nm long. Phase analysis by X-ray diffractometry revealed that the alloy thin sheets were fine crystalline. The average surface roughnesses measured by atomic force microscopy (AFM) were about 14.38 nm. Nano hardnesses determined by tribo-nano indenter were 4.13 GPa. The surface resistances were 2.28 ohm/sq. The maximum magnetization, residual magnetization and coercive force depended on the copper concentration.

• Elastomers and Composites
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• v.29 no.2
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• pp.113-120
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• 1994

The vulcanization characteristics, physical and electrical properties have been measured for magnetite-loaded CM compounds containing various concentration of magnetite. Samples of the various concentration of magnetite are characterized by oscillating disk rheometer, mooney viscometer, tensometer and resistance meter. The morphology and dispersion of magnetite are analyzed by scanning electron microscope(SEM). The results obtained are as follows : 1. The CM compound without magnetite shows plain curve, while the CM compounds containing magnetite show short curves. 2. The maximum volume of magnetite is 600 phr in the CM compounds. The magnetite of 30 to 150 phr of magnetite act as reinforcement agents and the 50 phr magnetite shows maximum tensile strength. 3. The electric conductivity is mostly influenced by the conditions of temperature, compacting pressure, and magnetite orientation. Further efforts should be made to develop a new design in various electric conductivity fillers for the most efficient and applicable rubber products.

• Mycobiology
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• v.30 no.2
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• pp.93-95
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• 2002

The antifungal activities of propolis on Cryptococcus neoformans and Candida albicans were evaluated. In microbroth culture assay, the MIC(minimum inhibitory concentration) of propolis for C. neoformans and C. albicans were 2 and 16 mg/ml, respectively. In propolis-included solid medium assay, the MIC of propolis for C. neoformans and C. albicans were 4 and 16 mg/ml, respectively. Propolis showed fungicidal activity against C. neoformans, whereas propolis possesed fungistatic activity against C. albicans. The MFC(minimum fungicidal concentration) for C. neoformans was 8 mg/ml. Cell morphology of C. neoformans was affected by treatment of propolis. In scanning electron microscope, the appearance of cell rupture was observed.