• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.1
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• pp.35-40
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• 2007

The new PEI(poly(epoxy-imide))-nano Silica film has been synthesized via in situ CS sol process, and the chemical bonding and microstructure of nano silica dispersed in resin were examined by FT-IR, TAG and SEM. The dielectric properties of these hybrid films over a given temperature and frequency ranges have been studied in a point of view of stable chemical bonding of nano Silica filler. The results from IR spectra and SEM photograph indicated that PEI-Silica hybrid film prepared with nano CS sol process has been synthesized in uniform and chemical bonding. The decrease property of dielectric constant with CS content, tangent loss consistent of given frequency and temperature has been explained in terms of the chain movement of polymer through chemical bonging and size effect of nano silica. The new PEI-CS sol hybrid film with such stable chemical and dielectric properties was expected to be used as a high functional coating application in ET, IT and electric power products.

• Journal of the Korean Society of Visualization
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• v.12 no.1
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• pp.49-53
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• 2014

In this study, a novel FDR-SPC is first synthesized in this study. The drag reducing functional radical such as PEGMA (Poly(ethylene) glycol methacrylate) has been utilized to participate in the synthesis process of the SPC. The types of the baseline SPC monomers, the molecular weight and the mole fraction of PEGMA were varied in the synthesis process. The resulting SPCs were coated to the substrate plates for the subsequent hydrodynamic test for skin friction measurement. In a low-Reynolds number flow measurement using PIV (Particle Image Velocimeter), a significant reduction in Reynolds stress was observed in a range of specimen, with the maximum drag reduction being 15.9% relative to the smooth surface.

• Polymer(Korea)
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• v.27 no.3
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• pp.169-175
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• 2003

Pyrophosphoric lactone modified polyester (PATT) containing two phosphorous functional groups in one unit structure was synthesized to prepare a non-toxic reactive flame-retardant coatings. Then the PATT was cured at room temperature with isocyanate, toluene diisocyanate-isocyanurate , to get a two-component polyurethane flame-retardant coatings (PIPUC). Comparing physical properties of the films of PIPUC with those of film of non-flame-retardant coatings, there was no deterioration observed in physical properties by the introduction of a flame-retarding component into the resin. We found that the char lengths measured by 45$^{\circ}$ Meckel burner method were 3.1∼4.4 cm and LOI values recorded 27∼30%. These results indicate that the coating prepared in this study is a good flame-retardant. The surface structure of coatings investigated with SEM does not show any defects and phase separation.

• The Journal of the Korean dental association
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• v.48 no.11
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• pp.819-828
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• 2010

Activator is a removable functional appliance used for correcting the skeletal Class II malocclusion in children with the mandibular deficiency. Berlin standard activator modified from Andresen activator has following characters; do not cover the palatal surface for tongue space, relief on lingual surface of mandibular incisors and resin capping 1/3-1/2 of crown height on mandibular incisors for preventing labioversion of mandibular incisors, L-hook between maxillary lateral incisor and canine for anterior high pull headgear, relief on mandibular posterior bite block for differential eruption of posterior teeth. Two cases presented here had a mandibular deficiency and slight maxillary protrusion. First case (an 11-year-old girl) treated with Berlin standard activator and anterior high pull headgear for 13 months followed by fixed orthodontic appliance for another 29 months. Second case (a 12-year-old boy) treated with Berlin standard activator for 6 months followed by fixed appliance for another 24 months. Treatment results showed a significant improvement in sagittal skeletal and occlusal relationship without premolar extraction. Mandibular condyles were concentric in TMJ [ossa, and masticatory muscle activities were normalized after treatment. In the retention period facial harmony and occlusal stability was maintained.

• Journal of the Korean Graphic Arts Communication Society
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• v.29 no.2
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• pp.1-13
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• 2011

The recent spotlight on electronic touch-screen display, a rapid breakthrough in the information society is evolving. Touch panel input device such as a keyboard or mouse without the use of, the on-screen character or a specific location or object on the person's hand touches a particular feature to identify the location of a panel is to be handled. The touch screen on the touch panel is used in the Ag paste is used mostly for low-curable paste. The thermal-curing paste according to the drying process of thermal energy consumption and improve the working environment of organic solvents have problems. In this study, Ag paste used in the non-thermal curing friendly and cost-effective UV curable paste was prepared. Current commercially available thermal-curable binder, was used instead of the flow characteristics of UV-curable oligomers and monomers with functional groups to give a single conductive Ag paste with the addition of a pattern could be formed. Ag paste as a result, thermal-curing adhesive, hardness, resistance and excellent reproduction of fine patterns and was available with screen printing environmentally friendly could see its potential as a patterning technology.

• Journal of Navigation and Port Research
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• v.32 no.9
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• pp.699-703
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• 2008

Fiber reinforced plastics (FRP) have been widely used because of their high specific strength, high specific stiffness and etc. Although these kinds of FRP have various merits in applications, it has been had one of the complicated problems to manufacture their wooden mold. For these reasons, the simple methods to manufacture the mold required in the FRP industries. To improve these kinds of problems, the molding system using composite materials was developed. By this new manufacturing techniques and high functional FRP composite mold was built. Comparing with wooden mold, the process efficiencies of frame manufacturing process and inner mold manufacturing process were improved approximately 40% and 70%, respectively.

• Resources Recycling
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• v.2 no.4
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• pp.27-32
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• 1993

A process has been studied to recover gallium from steelmaking dust which had several hundreds ppm of gallium. Aqueous solution containing 38 mg/l gallium was obtained by leaching of dust with 2.25 mol/l sulfuric acid. The leach liquor contained iron and zinc about 1,000 times greater than gallium. Gallium was then concentrated by ion exchanger of chelating resin with functional group of amino carboxylic acid after reduction of ferric ion to ferrous ion and pH adjustment. Gallium was concentrated to be 13 g/l in the resulting eluate by double ion exchanges. The liquor was further treated to remove impurities by solvent extraction technique empolying TOMAC as extractant. The galluim with 99% purity was finally obtainable.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.1
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• pp.57-64
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• 2013

The functional characteristic of LISN circuit, which is used for measurements of conductive noise in mains power line, is basically related to frequency characteristics of passive elements like inductors used in the circuit as well as the frequency response of inductors is highly related to the resins used in the varnishing process. The significant problem in determination of an inductor's frequency characteristic is the intrinsic resistance, inductance and parasitic capacitance. In this triplet, the parasitic capacitance is the major limiting factor of inductor's frequency range. This capacitance depends on inductor design parameters and materials filling the spaces of coil like resin and its coherency after curing process. In this paper, two similar inductors were designed and built. The first inductor was not varnished while the second one was varnished with VPI technology. VPI, or Vacuum, Pressure, Impregnation technology is one of the most reliable methods performing good insulating conditions for electrical circuits and windings based on resins. The measured results show that implying varnishing technology does not significantly affect the frequency response. However, due to mechanical solidity aspects and improved environmental protection, it is better to varnish the inductors.

• Journal of the Korean Applied Science and Technology
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• v.22 no.4
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• pp.371-378
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• 2005

In the previous study, three kinds of monomers and the functional monomer, acetoacetoxyethyl methacrylate (AAEM), which could improve the film property and cross-linkage, were polymerzied into acrylic resin copolymers (HSA-98-20, HSA-98-0, HSA-98+20) containing 80% solid content. In this study, the high-solid coatings(HSA-98-20C, HSA-98-0C, HSA-98+20C) were prepared by the curing reaction between acrylic resins containing 80% solid content and isocyanate at room temperature. Various properties were examined for the film coated with the prepared high-solid coatings. The introduction of AAEM in the coatings enhanced the abrasion resistance and solvent resistance of coatings, which indicated the possible use of high-solid coatings for top-coating materials of automobile. The curing times measured by viscoelastic measurement were 350, 264, and 212 min for HSA-98-20C, HSA-98-0C, and HSA-98+20C, respectively. This shows that the curing times become shorter with increasing $T_g$ values.

• Textile Coloration and Finishing
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• v.24 no.2
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• pp.131-137
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• 2012

para-Aramid fibers were treated by low-temperature plasma to improve the adhesion. The surface of para-aramid fibers were treated with gaseous plasma of several discharge power and treatment time in oxygen gas at 1Torr pressure. The treated fibers at low-temperature plasma were taken oxygen-containing functional groups and micro-crator on the surface. The modified fibers were measured by dynamic contact angle analyzer and XPS(X-ray photoelectron spectroscopy). The Interfacial adhesion properties of aramid fabric and polyurethane resin were determined by T-peel test. The surface of aramid fibers were observed by FE-SEM photographs. It was found that surface modification and chemical component ratio of the aramid fibers were improved wettability and adhesion characterization.