• 한국세라믹학회지
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• 제15권1호
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• pp.28-34
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• 1978

In order to develop the high refractory composite materials consisting of mullite and carborundum, Hadong kaolin and coal coke were selected as the starting materials. Silicone carbide crystals formed during the high-temperature reaction between kaolin and coke were detected by X-ray diffraction method and identified by electron diffraction. The temperature at which the amorphous silicone carbide begins to crystallize could be assumed to be about 155$0^{\circ}C$, which is the lower temperature claimed by others.

• 대한치과보철학회지
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• 제37권1호
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• pp.42-50
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• 1999

This study investigated the effects of surface treatment for filling resins on the surface texture of denture resin teeth by the use of scanning electron microscope. This study also evaluated the bond strength of filling resins to denture resin teeth. The denture resin teeth in this study was Endura Posterio(Shofu Co., Japan). The ailing resins used were Coe-cure(Coe Co., USA), Vertex RS (Dentimax Ziest, Holland), and light cured resin Z-100(3M Co., USA). The test sample were divided into 3 parts. Group 1 : Sandblasted with $50{\mu}m$ Aluminum oxide. Group 2 : Treated with #60 silicone carbide paper Group 3 : Treated with monomer brush application. Control Group : No Treatment. The results were as follows ; 1. The bond strength of filling resins to denture resin teeth is increased by surface treatment. 2. Regardless of the filling resins, there was a significant difference with # 60 silicone carbide paper treated group. 3. Regardless of each group, the bond strength according to the filling resins were decreased in the following order: Vertex RS, Coe-cure and Z-100.

• 한국염색가공학회지
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• 제1권1호
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• pp.35-46
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• 1989

Experiments described in which cotton fabrics at different stages of chemical processing were abraded to different extents on a Stoll Abrasion Tester with three different abradants, namely, a worsted fabric, flax fabric and silicon carbide paper. The four different plain-weave cotton fabrics selected were 1) desized, 2) scoured and bleached, 3) mercerized, 4) resin-treated. The surface abrasive damages of treated fabrics were observed by SAM, and load-elongation percent retentions of abraded samples were measured by Instrong Tester. The result were as follows: 1. The maximum percent retention of load-elongation with three different abradants was exhibited by the scoured and bleached fabrics and the minimum by the resin finished fabric. 2. The electron micrographs of four different cotton fabrics abraded by flax, worsted fabric abradants for 900 rubs showed a large number of criss-crossing stray fibers in fabric structure. It may be the molecular adhesion for frictional resistance to be explained. 3. The electron micrographs of four different cotton fabrics abraded by silicone carbide abradants showed the form of busing or mashing fibers in fabric structure. The above might be on the basis of the ploughing theory.

• Restorative Dentistry and Endodontics
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• 제13권1호
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• pp.123-129
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• 1988

The purpose of this study was to evaluate the bond strength of glassionomer cement against cut dentin surface which was treated with various surface cleaning agents. 48 freshly extracted human 3rd molars were ground flat through the enamel into the dentin using 600 grit silicone carbide paper under a flow of water. The were divided into four groups by the following cleaning procedure on cut dentin surface; Group I : No surface treatment after grinding with 600 grit silicone carbide paper as control group Group II : Surface treatment with 50% citric acid for 30 seconds. Group III : Surface treatment with 37% phosphoric acid for 30 seconds. Group IV : Surface treatment with 10% poly acrylic acid for 30 seconds. The specimens in 4 groups were immersed in distilled water at $37^{\circ}C$ for 24 hours before testing after cleanising with water-spray and drying with air. Bond strength was measured with Instron Universal Testing Machine (Autograph S-100, Shimadzu, Kyoto, JAPAN). The results were as follows: 1. The bond strengths of group II, III & IV were not seemed to be shown more significant improvement than a group I. 2. The bond strengths in groups which were treated with 50% citric acid, 37% phosphoric acid and 10% polycrylic acid, were ranked 24.70kg/$cm^2$, 22.02kg/$cm^2$ and 31.13kg/$cm^2$, but its difference was not significant, statistically.

• 대한기계학회논문집A
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• 제34권10호
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• pp.1499-1505
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• 2010

유연성 공구를 가진 자기연마는 고경도 소재 및 자유곡면 형상 표면의 나노메터급 가공이 가능한 강점을 지닌다. 이러한 자기연마에서 자기연마입자는 시간적, 비용적 측면에서 단순 혼합형 입자가 유리하다. 그러나 단순혼합형 입자는 가공 중 공구로부터 쉽게 이탈하게 되어 가공 시간이 증가 할수록 매우 낮은 가공 효율을 가진다. 따라서 본 연구에서는 단순 혼합형 입자에 오일을 대신하여 실리콘 겔을 매개물로 사용하는 자기연마 입자를 연구하고 그 특성을 분석하였다. 그 결과 자기력 향상과 별개로 입자간 응집력을 높여 입자의 이탈을 줄여 표면거칠기의 향상에 효과가 높음을 확인 하였다. 그리고 실험계획법을 이용하여 고경도 소재인 텅스텐 카바이드의 실리콘 겔 자기연마에서 각 공정변수가 표면거칠기의 향상에 미치는 특성을 평가하고 이를 최적화 하였다.

• Restorative Dentistry and Endodontics
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• 제14권2호
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• pp.65-76
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• 1989

The purpose of this study was to observe the effect on the removal of dentinal smear layer and morphological changes of reduced dentin surfaces by various dentin surface conditioners. Thirty-two healthy human premolars extracted due to periodontal or orthodontic reasons were used. The teeth were cross-sectioned to expose dentin at the middle portion of the crown with diamond rotary saw. The specimens were then divided into 8 groups. The sectioned dentin surfaces in group 1 to 4 were grinded with No. 400 grit silicone abrasive paper and those in group 5 to 8 were cut with #700 carbide bur under air-water spray. The grinded or cut dentin surfaces were conditioned with 3% $H_2O$, Dentin Conditioner(GC Inter. Corp., Japan), and Scotchprep(3M Dent Prod., U.S.A) according to manufacturer's directions. All the specimens were dried in room temperature for 48 hours, and gold-coated with Eiko ion coater(Eik-engineering Co.), and observed in Hitachi S-450 Scanning electron microscope at 15-25 KV. The following results were obtained; 1. The dentin surfaces grinded with the silicon abrasive paper were rougher in texture and heavier in amount of smear layer than those cut with the carbide bur. 2. Scrubbing of 3% $H_2O_2$ was not effective in removing dentinal smear layer. 3. 20-second conditioning of Dentin Conditioner (GC Inter. Corp) resulted in the removal of a significant amount of the smear layer without removing the tubular plugs and dissolving the peritubular dentin. 4. Scotchprep removed the smear layer very effectively. But at the same time it dissolved the peritubular dentin. 5. Irrespective of the uses of the silicon carbide abrasive paper or the carbide bur the morphological changes of dentin surfaces treated with the same conditioning agents were similar.

• 접착 및 계면
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• 제10권1호
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• pp.30-34
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• 2009

Two-phase 복합재료 계에서 성형압력이 열전도도에 미치는 영향을 고찰하였다. Polypropylene (PP) 고분자에 열전도성 필러인 Silicon carbide (SiC)를 40 vol% 첨가하여 압력을 0 MPa부터 20 MPa까지 시키면서 PP/SiC 복합재료의 계면과 열전도도의 변화를 관찰하였다. PP/SiC (40 vol%)에서 압력을 0에서 20 MPa를 증가시킴에 따라 복합재료 내부의 기포가 적어지고 고분자-필러와 필러-필러 계면에서의 접촉이 용이해져 포논산란이 감소되고 열전도도는 1.31 W/mK에서 1.86 W/mK로 약 40% 증가함을 확인하였다. 실험을 통하여 얻어진 열전도도 값과 Maxwell식과 Agari식을 이용한 Two-Phase계의 열전도도 예측값을 비교한 결과, 필러간의 상호작용을 고려하는 Agari예측식의 경우에 실험결과와 잘 일치하는 것을 확인하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2020년도 전력전자학술대회
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• pp.353-354
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• 2020

본 논문에서는 SiC (Silicone Carbide) MOSFET 기반 Buck-Unfolder 토폴로지를 적용한 단상 태양광 인버터를 개발한다. 개발한 인버터의 성능 평가를 위해 3.5kW 급 prototype의 효율 및 전고조파 왜율(THD)을 분석한다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 추계학술대회
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• pp.515-518
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• 2006

This paper presents the friction and wear characteristics of contact type sealing unit for a water turbine of a small hydro-power generation, which Is to stop a leakage of a circulating water from a outside of an impeller to an inside of a rolling bearing. The surface wear strongly affect to the seal life of a mechanical face seal. In this study, the hardness of a stainless steel in which is a heat-treated is 892.8 in Vickers hardness and the hardness of silicone carbide of SiC is 714.1 in Vickers hardness. The surface hardness of a heat-treated stainless steel is 25% high compared with that of a ceramic material of SiC. The contact modes of rubbing surfaces aye a dry friction a water film friction and a mixed friction that is contaminated by a dust, silt and moistures, etc. These two factors of a contact rubbing modes and a material property are very important parameters on the tribological performance such as a friction and wear between a seal ring and a seal seat. The experimental result shows that the surface hardness of a seal material is very important on the friction coefficient and a wear volume. Thus, the results recommend higher hardness of a seal material, which may reduce a friction loss and increase a wear life of primary seal components

• 한국분말재료학회지
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• 제25권5호
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• pp.375-378
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• 2018

Conductive and dielectric SiC are fabricated using electroless plating of Ni-Fe films on SiC chopped fibers to obtain lightweight and high-strength microwave absorbers. The electroless plating of Ni-Fe films is achieved using a two-step process of surface sensitizing and metal plating. The complex permeability and permittivity are measured for the composite specimens with the metalized SiC chopped fibers dispersed in a silicone rubber matrix. The original non-coated SiC fibers exhibit considerable dielectric losses. The complex permeability spectrum does not change significantly with the Ni-Fe coating. Moreover, dielectric constant is sensitively increased with Ni-Fe coating, owing to the increase of the space charge polarization. The improvements in absorption capability (lower reflection loss and small matching thickness) are evident with Ni-Fe coating on SiC fibers. For the composite SiC fibers coated with Ni-Fe thin films, a -35 dB reflection loss is predicted at 7.6 GHz with a matching thickness of 4 mm.