• Bulletin of the Korean Chemical Society
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• v.26 no.3
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• pp.470-472
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• 2005

• Proceedings of the Korean Vacuum Society Conference
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• 2003.02a
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• pp.170-170
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• 2003

• Bulletin of the Korean Chemical Society
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• v.24 no.10
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• pp.1538-1540
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• 2003

• Bulletin of the Korean Chemical Society
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• v.24 no.5
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• pp.681-683
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• 2003

• Journal of the Korean Chemical Society
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• v.54 no.6
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• pp.766-770
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• 2010

This is the study of magnetic properties of transition metal doped diluted magnetic semiconductors(DMSs). The wurtzite structure samples were synthesized by the sol-gel method. The thermodynamic characteristics and magnetic properties of $Zn_{1-x}Co_xO$ single phase was investigated for different doping concentration (x = 0%, 1%, 2%, 3%, 4%, 5%, 10%, 15%). The property of diluted magnetic semiconductors has been comfirmed by X-ray diffraction (XRD), Scanning Electronic Microscope (SEM) and Vibrating sample magnetometer (VSM). The magnetic properties of pure $Zn_{1-x}Co_xO$ is found to be dominated by the ferromagnetic interaction between doped transition metal ions, where by the ferromagnetic coupling strength is simply increased with the concentration(>5%) of the doped transition metal.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.333-333
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• 2013

The poor conductivity of poly (3,4-ethylene dioxythiophene): poly (styrenesulfonate) (PEDOT:PSS) film hinders to use for a flexible electrode in solar cells. In this report we demonstrate that the conductivity of PEDOT:PSS film can be enhanced by modifying structures in a mixture of PEDOT: PSS aqueous solution and various organic solvents such as polar protic (2-propanol, methanol, ethanol, formic acid) and aprotic solvents (acetone and acetonitrile). To comparatively study the structural effects on the resulted electrical properties, the films are spin-coated on glasses and ITO. At the same time, a contact angle goniometer is used for clarifying a mechanism of wettability of PEDOT (hydrophobic) and PSS (hydrophilic) on the observed conductivity. The structures and electrical properties are investigated by FE-SEM (Field Emission Scanning Electron Microscopy), AFM (Atomic Force Microscopy), and 4-point probe, respectively.

• Bulletin of the Korean Chemical Society
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• v.30 no.1
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• pp.201-204
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• 2009

$BaTiO_3/SrTiO_3$ and $PbTiO_3/PbZrO_3$ superlattice thin films were fabricated on $Pt/Ti/SiO_2/Si$ substrate by the pulsed laser deposition process. The morphologies and physical properties of deposited films were characterized by using X-ray diffractometer, HR-SEM, and Impedance Analyzer. XRD data and SEM images of the films indicate that each layer was well deposited alternatively in the superlattice structure. The dielectric constant of $BaTiO_3/SrTiO_3$ superlattice thin film was higher than that of individual $BaTiO_3$ or $SrTiO_3$ film. Same result was obtained in the $PbTiO_3/PbZrO_3$system. The dielectric constant of a superlattice film was getting higher as the number of layer is increased.

• Structural Engineering and Mechanics
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• v.6 no.6
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• pp.659-671
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• 1998

Exercise of complete control on all aspects of any manufacturing / fabrication process is very difficult, leading to uncertainties in the material properties and geometric dimensions of structural components. This is especially true for laminated composites because of the large number of parameters associated with its fabrication. When the basic parameters like elastic modulus, density and Poisson's ratio are random, the derived response characteristics such as deflections, natural frequencies, buckling loads, stresses and strains are also random, being functions of the basic random system parameters. In this study the basic elastic properties of a composite lamina are assumed to be independent random variables. Perturbation formulation is used to model the random parameters assuming the dispersions small compared to the mean values. The system equations are analyzed to obtain the mean and the variance of the plate natural frequencies. Several application problems of free vibration analysis of composite plates, employing the proposed method are discussed. The analysis indicates that, at times it may be important to include the effect of randomness in material properties of composite laminates.

• Journal of the Korean Society of Clothing and Textiles
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• v.24 no.1
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• pp.87-95
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• 2000

The changes on shrinkage, dyeability, antimicrobial activities and other physical properties of wool fabrics by chitosan treatment were investigated. A acid dye, a basic dye and natural artemisia were used for dyeing of wool fabrics. For Antimicrobial test of wool fabrics, S.Aureus was used. As the results, The wool fabrics treated with chitosan showed a marked decrease in shrinkage. Dyeability increased slightly as concentration of chitosan treatment increased, Dyeability of acid dye was the highest than other dyes. On the other hand, the dyeability of basic dye on chitosan treated fabrics was lower than untreated fabrics. Reduction rates of colony of chitosan-treated wool fabrics showed from 64.8% to 85.24% as chitosan concentration increased. Reduction rates of colony of the chitosan-treated fabrics decreased by dyeing with acid and basic dye. But increased by retreating with chitosan. Fabrics dyeing with atremisia showed above 90% reduction rate against S.Aureus on all chitosan concentrations. The Tensile properties of chitosan-treated fabrics showed little decrease. The moisture regain and the air permeability was decreased on chitosan concentration on 0.1% but recovered as chitosan concentration increased. The warmth retention was increased a little by chitosan treatment. The drapeability became hard as chitosan concentration increased.

• International Journal of Reliability and Applications
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• v.1 no.2
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• pp.133-143
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• 2000

Data from weighted distributions appear, among other situations, when some of the data are missing or are damaged, a case that is important in reliability and life testing. The kernel method for hazard rate estimation is discussed for these data where the basic large sample properties are given. As a by product, the basic properties of the kernel estimate of the distribution function for data from weighted distribution are presented.