• Textile Coloration and Finishing
• /
• v.20 no.2
• /
• pp.66-74
• /
• 2008

Effect of disperse dyeing on flame retardant finishing of PET fabrics via UV curing using three UV curable phosphorous-containing methacrylates and ammonium polyphosphate(APP) was investigated. The dye fixation and flame retardancy of PET fabrics did not change significantly with excellent durability to five laundering cycles irrespective of the dyeing and finishing sequence. However, the flame retardancy of Pekoflam-treated fabrics was lower than that of the UV treated and decreased substantially when heat treatment was carried out before the dyeing. The dyeability of the flame-retardant PET fabrics was not affected in the case of UV curing of the methacrylates alone. However, UV finishing after the dyeing caused significant decrease in K/S and ${\Delta}E$ due to changed refraction and inherent color of surface coating of the UV curable monomers and APP. Whereas the heat treatment with Pekoflam decreased both color fastness to laundering and sublimation, surprisingly the UV finish of PET fabrics before and after the dyeing increased the color fastness probably resulting from the presence of photopolymerized surface layer on the fabrics.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.26 no.1
• /
• pp.7-11
• /
• 2006

Since ceramic layers coated on machinery components inevitably experience the changes in their properties it is necessary to evaluate the characteristics of ceramic coating layers nondestructively for a reliable use of coated components and 4heir remaining life prediction. To address such a need, in the present study, an ultrasonic backward radiation technique is applied to investigate the characteristics of leaky Rayleigh surface waves propagating through the very thin TiN ceramic layers coated on AISI 1045 steel or austenitic 304 steel substrate with three different conditions of surface roughness, coating layer thickness and wear condition. In the experiments performed in the present work, the peak angle and the peak amplitude of ultrasonic backward radiation profile varied sensitively according to three specimen preparation renditions. in fact, this result demonstrates a high possibility of the ultrasonic backward radiation as an effective tool for the nondestructive characterization of the resting layers even in such a thin regime.

• Journal of Surface Science and Engineering
• /
• v.42 no.3
• /
• pp.109-115
• /
• 2009

Magnesium is one of the lightest metals, and magnesium alloys have excellent physical and mechanical properties such as high stiffness/weight ratios, good castability, good vibration and shock absorption. However their poor corrosion resistance, wear resistance, hardness and so on, have limited their application. To improve these defects, many techniques are developed. Micro arc oxidation(MAO) is a one of the surface treatments under anodic oxidation in which ceramic coating is directly formed on the surface of magnesium alloy. In this study, the characteristics of anodic film were examined after coating the AZ31B magnesium alloy through the MAO process. MAO was carried out in potassium hydroxide, potassium fluoride, and various concentration of sodium silicate in electrolyte. The morphology and chemical composition of the coating layer were characterized by SEM, XRD, EPMA and EDS. The hardness of anodic films was measured by micro-vickers hardness tester. As a result, the morphology and composition of anodic film were changed by concentration of sodium silicate. Thickness and Si composition of anodic film was increased with increasing concentration of sodium silicate in electrolyte. The hardness of anodic film was highly increased when the concentration of sodium silicate was above 40 g/l in electrolyte.

• Journal of Ocean Engineering and Technology
• /
• v.25 no.1
• /
• pp.39-43
• /
• 2011

This study has lowered the specific resistance by coating a thin film layer of Ag, playing the role of the electron donor on the ZnO that is used usefully for the transparent conductive oxides. Presently, this study has examined the transmittance and electric characteristics according to the thickness of the Ag thin film layer. Also, this study has observed the transmittance and electric characteristics according to the uppermost ZnO thin film layer of ZnO/Ag/ZnO symmetric film and has conducted the theoretical investigation. In order to observe the transmittance and electric characteristics according to the thickness of the Ag thin film layer and the uppermost ZnO thin film layer, this study conducted the film deposition at room temperature while making use of the DC magnetron sputtering system. In order to see the changes in the thickness of the Ag thin film layer, this study coated a thin film while increasing by 4nm; and, in order to see the changes in the thickness of uppermost ZnO thin film layer, it performed the thin film coating by increasing by 5nm. From the experimental result, the researchers observed that the best transmittance could be obtained when the thickness of the Ag thin film layer was 8nm, but the resistance and mobility increased as the thickness got larger. On the other hand, when the thickness of the uppermost ZnO thin film layer was 20nm, the experiment yielded the best transmittance with excellent electric characteristics. Also, when compared the ZnO/Ag asymmetric film with the ZnO/Ag/ZnO symmetric film, the ZnO/Ag asymmetric film showed better transmittance and electric characteristics.

• Journal of the Microelectronics and Packaging Society
• /
• v.23 no.2
• /
• pp.97-104
• /
• 2016

In the preparation of Ag-coated Cu flakes using L-ascorbic acid as a reductant for the electroless Ag plating, the effects of pretreatment methods and the reductant concentration on the uniformity of Ag coating layer and the anti-oxidation property of Ag-coated Cu flakes during the heating in air were evaluated. It was found that the removal degree of surface oxide layer during the pretreatment has great influence on the uniformity of Ag coating layer and the formation degree of hole defects in the flakes has slight effect on the anti-oxidation property of Ag-coated Cu flakes. It was also verified that the reductant concentration has great influence on the coverage uniformity and thickness of Ag coating, thus it was could be considered a main process parameter. When the reductant concentration was 0.04 M, high-quality Ag-coated Cu flakes was obtained. When the concentration increased to 0.06 M, however, the anti-oxidation property of Ag-coated Cu flakes became remarkably worse owing to remnant of Cu surface non-coated with Ag by the formation of pure Ag fine particles.

• Journal of Navigation and Port Research
• /
• v.38 no.3
• /
• pp.239-246
• /
• 2014

A study on the elution characteristics of biostimulating agents (sulfate and nitrate) from biostimulants which are used for in-situ bioremediation for the coastal sediment contaminated with organic matter was performed. The biostimulating agents were mixed with the coastal sediment, and then massed the mixture into ball. Two kinds of ball type biostimulant were prepared by coating the ball surface with two different polymers, cellulose acetate and polysulfone. A granular type biostimulant (GTB) was also prepared by impregnating a granular activated carbon in the biostimulating agent solution. The image of scanning electron microscopy for the biostimulant coated with cellulose acetate (CAB) showed that the inner side of the coating layer consisted of irregular and bigger size of pores, and the surface layer had tight structure like beehive. For the biostimulant coated with polyfulfone (PSB), the whole coating layer had a fine structure without pore. The elution rate of the biostimulating agents for the CAB was higher than that for the PSB, and the elution rate for the GTB was considerably higher than that for the PSB in distilled water as well as in sea water. The elution rate of the biostimulating agents in turbulent water flow was about 3 times higher than that in standing water, and the elution rate of nitrate was higher than that of sulfate from the stimulating agents.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.41 no.2
• /
• pp.64-69
• /
• 2009

Cultural heritages represent the histories and intellectual level of a country. The Annals of Joseon Dynasty are regarded as the most valuable resources containing the record of Korean history. In some periods, wax-treated paper was used as the material of the Annals of Joseon Dynasty. Many previous studies have focused on the development of paper used as the material of the Annals of Joseon Dynasty, but the manufacture method of wax-treated volumes and the degradation mechanism of wax have been not fully understood yet. The purposes of the present study are to produce various kinds of wax-treated paper using by different coating methods and to analyse the morphological properties of wax-treated paper. The analysis of SEM demonstrates that beeswax treated paper made by brushing method produces flatter surface and more excellent penetration. Wax layer is produced on the cross section of beeswax treated paper as the increase of coating amount.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.33 no.6
• /
• pp.389-395
• /
• 2009

A specially designed flat plate was mounted vertically over the axial line in the wind tunnel of the Pusan National University. Strain balances were mounted in the trailing part of the plate to measure the skin friction drag over removable insertions of $0.55{\times}0.25m^2$ size. A set of the insertions was designed and manufactured: 3 mm thick polished metal surface and three compliant surfaces. The compliant surfaces were manufactured of a silicone rubber Silastic$^{(R)}$ S2 (Dow Corning company). To modify the viscoelastic properties of the rubber, its composition was varied: 90% rubber + 10% catalyst (standard), 92.5% + 7.5% (weak), 85% + 15% (strong). Modulus of elasticity and the loss factor were measured accurately for these materials in the frequency range from 40 Hz to 3 kHz. The aging of the materials (variation of their properties) for the period of one year was documented as well. Along with the drag measurement using the strain balance, velocity and pressure were measured for different coating. The strong compliant coating achieved 5% drag reduction within a velocity range $20{\sim}40$ m/s while standard and weak coatings increased drag reduction.

• Biomedical Science Letters
• /
• v.17 no.3
• /
• pp.211-216
• /
• 2011

The chitosan-coated liposomes (chitosomes) were designed to improve the stability in the gastrointestinal (GI) tract and to enhance the efficacy for oral drug delivery of liposomes. The phosphatic acid (PA)-incorporated anionic liposomes were surface-coated with water soluble chitosan (WSC) by electro-ionic interaction. The shape of the chitosomes observed by transmission electron microscopy (TEM) was spherical in all the formulations and the coating layer by WSC could be founded through TEM images. The mean size and the zeta potential values of the chitosomes increased significantly with depending on the content of WSC added for coating the liposomes. The stability of the chitosomes in the GI tract was confirmed through the change of relative turbidity of the liposomal suspension. The plain liposomes (plasomes) suspension without adding WSC clearly showed the change of relatively turbidity in simulated gastric fluid (SGF), while the change degree of turbidity of the chitosomes in the SGF decreased as increasing of WSC content added for coating liposome. In the 5-CF release study from the plasomes and chitosomes, the plasomes released >90% of the initial 5-CF content at 4 h of release measurement. In contrast, the chitosomes released below 40% of initial content of 5-CF. In conclusion, these results indicate that the chitosomes can be used as a potential carrier for effective oral drug delivery.

• Journal of Welding and Joining
• /
• v.18 no.3
• /
• pp.51-59
• /
• 2000

Sink roll has been used in molten 55%Al-Zn alloy bath of continuous galvanizing line for sinking and stabilizing working steel strip in molten metal bath. In the process, the sink roll body inevitably build up dross compounds and pitting on the sink roll surface during 55%Al-Zn alloy coated strip production, and the life time of the sink roll is shorten by build up dross compounds and pitting. The present study examined the application of thermally sprayed ceramic coatings method on sink roll body for improving erosion resistance at molten 55% Al-Zn pool. In this experiment, the stainless steels such as STS 316L and STS 430F were used as the substrate materials. The CoNiCr and WE-Co powder were selected as bond coating materials. Moreover $Al_2O_3-ZrO_2-SiO_2 and ZrO_2-SiO_2$ powders selected as the top coating materials. Appearances of the specimens before and after dipping to molten 55%Al-Zn pool were compared and analyzed. As a result of this study, STS430F of substrate, WC-Co of bond spray coatings, $ZrO_2-SiO_2$ power of top spray coatings is the best quality in erosion resistance test at molten 55%Al-Zn pool