• The Journal of Advanced Prosthodontics
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• 제10권3호
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• pp.177-183
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• 2018

PURPOSE. The purpose of the current study was to evaluate the effect of incorporating nanoparticles of silver (NAg) and amorphous calcium phosphate (NACP) into a self-etching primer of a resin cement on the microtensile bond strength of dentin, regarding the proven antibacterial feature of NAg and remineralizing effect of NACP. MATERIALS AND METHODS. Flat, mid-coronal dentin from 20 intact extracted human third molars were prepared for cementation using Panavia F2.0 cement. The teeth were randomly divided into the four test groups (n=5) according to the experimental cement primer composition: cement primer without change (control group), primer with 1% (wt) of NACP, primer with 1% (wt) of physical mixture of NACP+Nag, and primer with 1% (wt) of chemical mixture of NACP+Nag. The resin cement was used according to the manufacturer's instructions. After storage in distilled water at $37^{\circ}C$ for 24 h, the bonded samples were sectioned longitudinally to produce $1.0{\times}1.0mm$ beams for micro-tensile bond strength testing in a universal testing machine. Failure modes at the dentin-resin interface were observed using a stereomicroscope. The data were analyzed by one-way ANOVA and Tukey's post-hoc tests and the level of significance was set at 0.05. RESULTS. The lowest mean microtensile bond strength was obtained for the NACP group. Tukey's test showed that the bond strength of the control group was significantly higher than those of the other experimental groups, except for group 4 (chemical mixture of NACP and NAg; P=.67). CONCLUSION. Novel chemical incorporation of NAg-NACP into the self-etching primer of resin cement does not compromise the dentin bond strength.

• The Transactions of the Korean Institute of Electrical Engineers C
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• 제53권1호
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• pp.1-7
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• 2004

This paper describes the carbonization characteristics of a phenolic resin deteriorated by tracking under the environment of a fire. In the experiment, a liquids droplet of 1[％] NaCl was dripped on the phenolic resin to cause a tracking with 110[V], 220[V] voltages applied. It can be addressed from the experimental results that when an insulator is carbonized by an external fire, its structure is amorphous. If an insulator is carbonized by electrical cause, on the other hand, its structure would be crystalline. In order to observe the surface change of the phenolic resin, the tracking process was analyzed by using SEM. In the case that the materials are carbonized under heat or fire, the exothermic peak appears around 500[$^{\circ}C$]. This is one of the important factors to determine the cause of fires. As a result of DTA, the exothermic peaks of an untreated sample showed at 333.4[$^{\circ}C$], 495.7[$^{\circ}C$] but those of a sample deteriorated by tracking appeared at 430.6[$^{\circ}C$], 457.6[$^{\circ}C$] in a voltage of 110[V], and at 456.2[$^{\circ}C$], 619.7[$^{\circ}C$] in a voltage of 220[V]. It is possible, therefore, to distinguish a virgin sample from carbonized samples(graphite) by the exothermic peak.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.629-632
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• 1999

For replacing Li metal ai Lithium ton Bakery(LIB) system. we used carbon powder material which prepared by pyrolysis of phenol resin as starting material. It became amorphous carbon by pyrolysis through it\`s self condensation by thermal treatment. Amorphous carbon can be doped with Li intercalation and deintercalation because it has wide interlayer. however it has a problem with structural destroy causing weak carbon-carbon bond. So. we used ZnCl$_2$ as the pore-forming agent. This inorganic salt used together with the resin serves not only as the pore-forming agent to form open pores, which grow Into a three-dimensional network structure in the cured material, foul also as the microstructure-controlling agent to form a loose structure dope with bulky dopants. We analyzed SEM in order to find to different of structure. and can calculate distance of interlayer. CV test showed oxidation and reduction

• Journal of Biomedical Engineering Research
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• 제18권1호
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• pp.1-8
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• 1997

This study was performed to evaluate the effect of resin and filler type on the compressive strength of light-activated composite resins. Experimental composite resins containing either amorphous spherical silica or crushed quartz in two matrix resins of BisGMA/TEGDMA and UTMA/TEGDMA were prepared and the specimens of 3 m in diameter and 6m in length were made. Compressive test was subjected to a crosshead speed of 0.5 mm/min, and the fracture surFaces were examined by SEM. The compressive strength of UTMA-based composite resin was higher than that of BisGMA-based composite resin. The loading rate of spherical silica was higher than that of crushed silica when the size dis- tribution of fillers was same. Strength decrease of Bis-GMA-based composite resin was severer than that of UTMA-based composite resin in a $37^{\circ}$c water environment. Fracture surface showed that the composite resin failure developed along the matrix resin and the filler/resin interface region.

• Textile Coloration and Finishing
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• 제31권4호
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• pp.354-362
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• 2019

In order to apply thermoplastic composites using PETG resin to various industrial fields such as bicycle frames and industrial parts, it is necessary to verify the impact resistance, durability and mechanical properties of the manufactured composite materials. To improve the mechanical properties, durability and impact resistance of PETG resin, an amorphous resin, in this study, compound and injection molding process were carried out using various additives such as TiO2, carbon black, polyolefin elastomer, and PETG amorphous resin. The thermal and mechanical properties of the thermoplastic composites, and the Charpy impact strength. The analysis was performed to evaluate the characteristics according to the types of additives. DSC and DMA analyzes were performed for thermal properties, and tensile strength, flexural strength, and tensile strength change rate were measured using a universal testing machine to evaluate mechanical properties. Charpy impact strength test was conducted to analyze the impact characteristics, and the fracture section was analyzed after the impact strength test. In the case of POE material-added thermoplastic composites, thermal and mechanical properties tend to decrease, but workability and impact resistance tend to be superior to those of PETG materials.

• Design & Manufacturing
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• 제13권2호
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• pp.12-16
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• 2019

For optimal injection molding, various molding conditions should be combined well. Therefore, engineers should be thoroughly familiar with mold design, fabrication, and injection molding. The choice of resin among the various molding conditions is closely related to the productivity of the molded part and the deformation after molding, so the engineer must select the appropriate resin. Engineers work on the basis of data provided by resin manufacturers during molding. However, in actual molding work, it is necessary to apply values slightly different from those provided to obtain molded articles of desired performance. In this study, various deformations of molded products were compared with respect to crystalline resin and amorphous resin when molded according to the data provided by the resin maker and molded at the changed values at the work site.

• Journal of the Korean Electrochemical Society
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• 제3권2호
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• pp.85-89
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• 2000

For replacing Li metal at Lithium ion Battery(LIB) system, we used carbon powder material which prepared by Pyrolysis of Phenol resin as starting material. It became amorphous carbon by Pyrolysis through it's self condensation by thermal treatment. Amorphous carbon can be doped with Li intercalation and deintercalation because it has wide interlayer. However, it has a problem with structural destroy due to weak carbon-carbon bond. So, we used $ZnCl_2$ as the pore-forming agent. This inorganic salt was used together with the resin serves not only as the pore-forming agent to form open pores, which grow into a three-dimensional network structure in the cured material, but also as the microstructure-controlling agent to form a loose structure doped with bulky dopants. We used SEM in order to find to difference of structure, and can calculate the distance of interlayer by XRD analysis. CV test showed oxidation and reduction.

• Restorative Dentistry and Endodontics
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• 제44권3호
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• pp.24.1-24.1
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• 2019

• Proceedings of the KIEE Conference
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 C
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• pp.965-967
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• 1999

In order to solve to instability in air and to format dentrite, we used carbonized phenol resin electrode which is amorphous carbon. The structure and properties of deeply Li-doped carbonized phenol resin have been investigated in association with their utilization as electrodes in rechargeable batteries. Resol type phenol resin used as starting material. The doped lithium was found neither in metallic nor in ionic states even in the most deeply doped state($C_{2.2}$Li stage). It has also been confirmed that the carbonized phenol resin electrode has a large capacity with good stability and reversibility. These results strongly suggest that the carbonized phenol resin can make an excellent anode material for secondary batteries. Finally, we discuss that the carbonized phenol resin doped up to the $C_2Li$ stage can exhibit an energy density per volume as high as lithium metal. We know that carbonized phenol resin can used as cathode as well as anode by cyclic voltammogram.

• Journal of the Korean Applied Science and Technology
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• 제18권2호
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• pp.153-159
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• 2001

Due to its low density, good mechanical properties and chemical inertness, glassy carbon(GC) has been studied for appications in several fields. A raw thermosetting resin of furanic resin was polymerized with a curing agent of p-toluenesulfonic acid monohydrate. The maximum yield of GC was obtained at the curing agent content of 1.0 wt% in furanic resin. In order to make thick GC, the affect of graphite filler addition to the furanic resin was investigated. The density and electrical resitivity of GC after graphitization were 1.45 $g/cm^{3}$ and 47 ${\times}10^{-4}$ ${\Omega}$ ${\cdot}$ cm respectively and the amorphous structure of GC was confirmed by XRD profiles with very broad peaks comparable to those of graphite at $206^{\circ}$ and $45^{\circ}$.