• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1177-1184
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• 2011

Ceramic insert and anchor has many advantages compared with existing steel products, therefor widely applied for concrete bridge, tunnel, railroad and building etc. in Japan. Ceramic insert and anchor start-to-used in Korea is no longer, but the product has already been applied to various construction sites and have been recognized for excellence. But now in Korea, the ceramic insert and anchor are not yet widely use like in Japan. This paper was an introduction to the ceramic insert and anchor, and detailed explained the product excellent performance. Ceramic insert and anchor can be applied to many areas, but in this case the focus was the application of ceramic insert and anchor for railway structures. In this paper we detailed compared the ceramic products with existing steel products in their respective characteristic, and analyzed on their application in domestic and foreign.

• The Korean Journal of Ceramics
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• 제4권4호
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• pp.340-344
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• 1998

Failure mechanisms were investigated for the two layer thermal barrier coatings consisting of NiCrAlY bond coat and $ZrO_2$-8wt.% $Y_2O_3$ ceramic coating during cyclic oxidation. $Al_2O_3$ developed at the ceramic coating/bond coat interface first, followed by the Cr/Ni rich oxides such as $NiCr_2O_4$ and $Ni(Al, Cr)_2O_4$ during cyclic oxidation. It was observed that the spalling of ceramic coatings took place primarily within the NiCrAlY bond coat oxidation products or at the interface between the bond coat oxidation products and zirconia based ceramic coating or the bond coat. It was also observed that the fracture within these oxidation products occurred with the formation of $Ni(Cr, Al)_2O_4$ spinel or Cr/Ni rich oxides. It was therefore concluded that the formation of these oxides was a life-limiting event for the thermal barrier coatings.

• 디지털융복합연구
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• 제11권2호
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• pp.391-396
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• 2013

최근 사람들과 제품사이에 관계성의 중요도가 부각되면서, 순수한 기능적인에서도 감성을 추구하는 추세이다. 소비자 본인의 감성에 맞는 상품을 찾고 구매하는 과정에 감성요인이 중요한 부분이다. 본 연구는 도자장신구의 문화산업에 다변화하는 감성디자인의 역할과 발전 가능성을 살펴보는데 목적이 있다. 문화산업시장을 파악하고 도자장신구를 감성적 디자인으로 다양하게 디자인을 유도하여, 세계적인 공정에 맞설 수 있는 공예문화상품으로 개발, 도자장신구의 역사적, 문화적, 디자인적 가치를 바탕으로 다양한 문화산업에서 활용 가능하도록 감성적 디자인 도자장신구를 제안, 도자장신구 제품디자인 발전방안에 이바지함을 목적으로 한다.

• 한국세라믹학회지
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• 제56권6호
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• pp.596-600
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• 2019

Artificial intelligence with a sufficient amount of realistic big data in certain applications has been demonstrated to play an important role in designing new materials or in manufacturing high-quality products. To reduce cracks in ceramic products using machine learning, it is desirable to utilize big data in recently developed data-driven optimization schemes. However, there is insufficient big data for ceramic processes. Therefore, we developed a numerical algorithm to make "virtual" manufacturing data sets using indirect methods such as computer simulations and image processing. In this study, a numerical algorithm based on the random walk was demonstrated to generate images of cracks by adjusting the conditions of the random walk process such as the number of steps, changes in direction, and the number of cracks.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2005년도 제24회 춘계학술대회논문집
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• pp.106-111
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• 2005

Failure mechanisms were investigated for the two layer thermal barrier coatings consisting of NiCrAlY bond coat and $ZrO_2-8wt.\% Y_{2}O_3$ ceramic coating during cyclic oxidation. $Al_{2}O_3$ developed at the ceramic coating/bond coat interface first, followed by the Cr/Ni rich oxides such as $NiCr_{2}O_4 and Ni(Al,Cr)_{2}O_4$ during cyclic oxidation It was observed that the spalling of ceramic coatings took place primarily within the NiCrAlY bond coat oxidation products or at the interface between the bond coat oxidation products and zirconia based ceramic coating or the bond coat. It was also observed that the fracture within these oxidation products occurred with the formation of $Ni(Cr,Al)_{2}O_4$ spinel or Cr/Ni rich oxides. It was therefore concluded that the formation of these oxides was a life-limiting event for the thermal barrier coatings.

• 한국세라믹학회지
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• 제53권4호
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• pp.444-449
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• 2016

Industrial by-products generated by integrated iron and steel manufacture cause environmental pollution. The by-products contain not only iron element but also harmful substances. Therefore, in view of to waste recycling and environmental preservation, production of sponge iron using the by-product is considered an effective recycling method. In this study, reduction efficiency of pellets from blast furnace dust was measured. Metallization was found to be increased, as $C/Fe_{total}$ ratio and reaction time were increased. The pellets were formed into a globular shape, and calcined for 60 minutes at $1100^{\circ}C$ in an electric furnace. Phase changes were analyzed using an X-ray diffractometer. Microstructures of the pellets were observed by a scanning electron microscope.

• Carbon letters
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• 제5권4호
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• pp.164-169
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• 2004

Carbon-ceramic composites refer to a special class of carbon based materials which cover the main drawbacks of carbon, particularly its proneness to air oxidation, while essentially retaining its outstanding properties. In the present paper, the authors report the results of a systematic study made towards the development of C-SiC-$B_4C$ composites, which involves the effects of compositional parameters, namely, carbon-to-ceramic and ceramic-to-ceramic ratios, on the oxidation behaviour as well as other characteristics of these composites. The C-SiC-$B_4C$ composites, heat-treated to $1400^{\circ}C$, have shown that their oxidation behaviour at temperatures of 800~$1200^{\circ}C$ depends jointly on the total ceramic content and the SiC : $B_4C$ ratio. Good compositions of C-SiC-$B_4C$ composites exhibiting zero weight loss in air at temperatures of 800~$1200^{\circ}C$ for periods of 4~9 h, have been identified. Composites with these compositions undergo a weight gain or a maximum weight loss of less than 3% during the establishment of a protective layer at the surface of carbon in a period of 1~6 h. Significant improvement in the strength of C-SiC-$B_4C$ composites has been observed which increases with an increase in the total ceramic content and also with an increase in the SiC : $B_4C$ ratio.

• 한국분말재료학회지
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• 제26권6호
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• pp.508-514
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• 2019

In the development of advanced ceramic tools, material improvements and design freedom are critical in improving tool performance. However, in the die press molding method, many factors limit tool design and make it difficult to develop innovative advanced tools. Ceramic 3D printing facilitates the production of prototype samples for advanced tool development and the creation of complex tooling products. Furthermore, it is possible to respond to mass production requirements by reflecting the needs of the tool industry, which can be characterized by small quantities of various products. However, many problems remain in ensuring the reliability of ceramic tools for industrial use. In this study, alumina inserts, a representative ceramic tool, was manufactured using the digital light process (DLP), a 3D printing method. Alumina inserts prepared by 3D printing are pressurelessly sintered under the same conditions as coupon-type specimens prepared by press molding. After sintering, a hot isostatic pressing (HIP) treatment is performed to investigate the effects of relative density and microstructure changes on hardness and fracture toughness. Alumina inserts prepared by 3D printing show lower relative densities than coupon specimens prepared by powder molding but indicate similar hardness and higher fracture toughness values.

• 한국결정성장학회지
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• 제27권5호
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• pp.256-262
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• 2017

$1000^{\circ}C$ 이상의 고온에서도 안정적인 발색 특성을 보이는 세라믹 잉크를 활용한 디지털 프린팅 기술은 우수한 내구성을 가지는 제품을 다양한 디자인을 적용하여 생산할 수 있는 친환경 공정이라는 장점으로 인해 최근 관심이 높아지고 있다. 특히 건축용 세라믹 타일 산업에서 잉크젯 프린팅 기술 도입을 통한 디지털 공정으로의 전환은 점점 가속화되고 있으며, 이와 관련된 프린팅 시스템 및 고온발색 세라믹 잉크에 관한 연구가 활발히 진행되고 있다. 본 연구에서는 세라믹 타일의 표면 유약층에서 고온발색 세라믹 잉크의 인쇄적성을 분석하였다. 디지털 4원색인 Cyan, Magenta, Yellow, Black 색상의 고온발색 세라믹 잉크가 프린팅된 세라믹 타일의 표면 및 단면의 미세구조를 분석함으로써 세라믹 잉크의 종류에 따른 인쇄특성에 대해 비교하였다. 또한 고온 열처리 공정이 필수적으로 요구되는 세라믹 소재의 특성상 잉크젯 프린팅 후 세라믹 잉크 패턴의 열처리 공정에 따른 거동변화에 관하여 고찰하였으며, 세라믹 타일 유약층에서 세라믹 잉크의 인쇄적성은 미세구조 및 고온 소성 과정에 큰 영향을 받고 있음을 확인하였다.

• 한국재료학회지
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• 제20권4호
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• pp.181-186
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• 2010

Since it was developed by Joseph Aspdin, cement has been a common construction materials up to the present time. However, there are trace constituents in cement clinker. One of the trace constituents included in cement clinker, chromium, has become prominent and highly noticed lately as a social issue both inside and outside of this country because it affects the human body negatively. The aim of the present study was to investigate the concentration of water-soluble hexavalent chromium in cement clinker by using industrial by-products. For that reason, raw materials were prepared to add different $SiO_2$, $Al_2O_3$, and $Fe_2O_3$ sources. After the raw materials such as the limestone, the sand and the clay, iron ore was pulverized and mixed, and the raw meal was burnt at about $1450^{\circ}C$ in a furnace with an oxidizing atmosphere. The part in the raw materials of the clinker was substituted with slag, sludge, etc. and this was used to manufacturing cement clinker. To investigate the water-soluble hexavalent chromium content in clinker, raw meal was prepared by changing the modulus, the type, and the content of clinker materials and tested concentrations of hexavalent chromium in the clinkers. To determine $Cr^{+6}$ formation of the clinker, tests were done with raw meals adding chromium by using different industrial by-products. Consequently because the chromium was to be included in the raw materials of the clinker, production of Portland cement clinker was included with the chromium. Also, the chromium was converted into hexavalent chromium in the burning process.