• 자원환경지질
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• 제4권3호
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• pp.113-119
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• 1971

The Daeheung Dolomite Mine, which is about 6km south of Danyang, Chungcheongbugdo, is coincided with almost central portion of the Danyang quardrangle scaled in 1 : 50,000. The purpose of this report is to prepare a information for the economic evaluation on the mine. Geology of the region is composed of worm-eaten limestone, crystalline limestone, crystalline dolomite rock, sandstone and shale from bottom, those are applicable to socalled Dumugol and Maggol formation of Ordovician, and batholithic biotite granite is intruded the west-side of the ditto sedimentary rocks. The dolomite bed, emplaced in bottom of the upper limestone formation, so-called Maggol formation, is about 270m in thickness, and dips $30^{\circ}{\sim}50^{\circ}$ northwest. The facies of the dolomite rock contained many brucite crystals is not only coarse-grained crystalline, but also micro crystalline in contact metasomatic parts. 25 samples were taken from the two series, A and B, in the nearly crossed direction to the strike of the dolomite bed as shown in the geological map. They were chemically analysed on the components of MgO, CaO, and $SiO_2$ as shown in Table 2. The estimate ore reserves total some 107,200,000 metric tons above the 320m level with the following average contents: MgO 21.80%, CaO 29.27% and $SiO_2$ 0.64%. It is caused by brucite minerals that MaO content in the dolomite rock is higher than pure dolomite (21.7%). The dolomite ore is possible in use for magnesian fertilizer, magnesian cement and refractory material, especially the microcrystalline dolomite ore is useful for a refractory material in furnaces of iron industries.

• 한국주조공학회지
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• 제17권6호
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• pp.569-576
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• 1997

Coating materials for Evaporative Pattern Casting (EPC) process have been developed to investigate the effect of refractories on coating material properties. Three types of developed and one foreign coating materials were used. The former designated as A, B, C and the latter named S.K. The refractory of coating material A is spherical shape of zirconia, and the ones of B, C and S.K. is flake shape of mica. Strength, permeability at room and elevated temperature, anti-sand attachability and carbon residuary were evaluated at each coating materials. Permeability measurement device for elevated temperature was also designed. The zirconia type of coating material had excellent permeability, on the other hand the mica type had good strength and anti-sand attachability. It was found that the refractories were not broken during casting, so permeability indicated same trend at both room and elevated temperature. Based on results, coating material contained small size of mica which is designated as B has the best combination for cast iron.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.909-912
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• 2001

Lanthanide orthochromite materials have been widely studied as refractory conducting ceramics because of their electrical conductivity, oxidation resistance and high melting points. In this paper theoretical and experimental analysis about electric conductivity of the SHS prepared ceramics was carried out. The usefulness of the Seebeck-coefficient measurements as a function of P(O$_2$) is emphasized. Electronic conduction was found to be n-type in the lower P(O$_2$) range, and p-type in the higher P(O$_2$) range. The carrier concentrations were calculated as a function of P(O$_2$) and defect structure.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.211-214
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• 2001

The undesirable phase transformation of zirconium dioxide at high temperatures can be eliminated by stabilization of the cubic phase with an addition of a selected alkaline earth or rare-earth oxide. In this paper the ionic conductivity of cubic solid solutions in the stabilized ZrO$_2$ by CaO-Y$_2$O$_3$ system was examined. The higher ionic conductivity appears to be related to lower activation energy rather than to the number of oxygen vacancies dictated by composition. Those compositions of highest conductivity lie close to the cubic-monoclinic solid-solution phase boundary. Conductivity temperature data are presented that indicate a reversible order-disorder transition for Zr$_2$2-Y$_2$O$_3$cubic solid solutions containing 20 and 25 mole % $Y_2$O$_3$.

• 대한치과의사협회지
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• 제25권11호통권222호
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• pp.1019-1028
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• 1987

결손된 치질과 변색된 법랑질을 수복하기 위해 많은 재료와 술식이 개발되어왔다. 즉 silicate cement, PMMA resin, BISGMA composite resin, glass ionomer cement, porcelain등이 이용되어 왔으나 이것들은 biocompatible하지 않아 이상적인 재료는 아니다. 따라서 인간의 결손된 enamel을 수복할 수 있는 새로운 생역학적인 재료가 필요하게 되었다. 필자는 최근 관심의 대상이 되고 있는 porcelain laminate veneer system(층상 도재 전장관)에 관하여 문헌을 중심으로 고찰해 보고자 한다(국내에서는 장완식 교수께서 1987년 6월10일 보철학교실 세미나에서 video tape를 통해 소개한바 있음). 여기서는 Hobo, Iwata(1985)등이 소개한 castable apatite ceramic material을 이용한 laminate veneer술식에 관해 기술하고 내화성 모형(refractory cast)을 이용한 laminate술식과 비교 기술하고자 한다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1988년도 춘계학술대회 논문집
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• pp.43-45
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• 1988

Four W/Cu system(60wt%W-40wt%Cu, -0.lwt%Ni, -0.5wt%Ni, -0.lwt%C) and four WC/Cu system(60wt%WC-40wt%Cu, -0.lwt%Ni, -0.5wt%Ni, 0.lwt%C) electrical contacts were prepared by a press-sinter-infiltration process to compare with their properties. Hardness and electrical conductivity are proportional to the refractory metal(W or WC) properties and showed the effect of additives. Arc erosion trend of switch test is changed by current level. High currant test at 1kA showed a different crack formation pattern and erosion mode between W/Cu system and WC/Cu system contacts.

• 한국정밀공학회지
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• 제15권6호
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• pp.48-57
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• 1998

Abrasive waterjet(AWJ)은 가공시 열에 의한 가공경화가 없기 때문에 유리, 세라믹, 타이타늄및 금속복합재료와 같은 난삭재의 가공기술로 사용이 증가되었다. Acoustic emission(AE)신호에 의한 AWJ 세라믹 drilling가공시 On-Line Monitoring의 가능성이 고찰되었다. 기계 적인 물성이 서로 상이한 3종류의 세라믹이 본 연구에서 사용되었으며, AE신호는 AWJ drilling의 깊이를 monitoring하는데 유용함을 알 수 있었고 또한 세라믹의 material removal mechanisms을 규명하였다.

• 한국전기전자재료학회논문지
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• 제15권4호
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• pp.349-355
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• 2002

The ionic conductivity of cubic solid solutions in the systems of CaO-$ZrO_2$, $Y_2O_3-ZrO_2$ prepared by SHS was examined. The higher conductivity appears to be related to a lower activation energy rather than to the number of oxygen vacancies dictated by composition. Conductivity-temperature data was obtained at 1000 $^{\circ}C$ in atmosphere of low oxygen partial pressure (~$10^{-40}$ atm) for $Y_2O_3-ZrO_2$ cubic solid solutions. The data indicated that these materials could be reduced, and the decree of reduction would be related with the measuring electric field.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 봄 학술논문 발표대회
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• pp.140-141
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• 2020

Concrete has a lower thermal conductivity or thermal diffusion coefficient compared to other building materials, so it is widely used as fireproof compartment material or refractory material for structures. However, in the event of thermal damage such as fire, cement curing agents and aggregates act differently, resulting in heat generation or deterioration of tissue due to dehydration, resulting in deterioration of physical properties and fire resistance. Therefore, in this study, the processing structure of cement paste is measured through nitrogen absorption method. The test specimen is a cement paste of 40% W/C and is set at 1000 ℃ under heating temperature conditions. As the temperature rose, the micro-pore mass below was reduced based on about 0.01 감소m, but the air gap above that was increased.Thus, in the range of pores measured in nitrogen adsorption, the air mass tended to decrease under high temperature conditions.

• 대한전자공학회논문지
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• 제22권4호
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• pp.76-83
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• 1985

RMOS(refractory metal oxide semiconductor)의 게이트와 집적회로의 각 소자나 회로를 연결하는 연결선으로 사용되는 Mo2N/Mo 이중층을 Ar과 N2의 혼합가스 분위기에서 저온의 고주파 반응성스펏터링으로 형성하였다. 1000Å-Mo2N/4000Å-Mo이중층의 면저항은 약 1.20∼1.28Ω/구로서 다결정실리콘의 약 1/10정도가 되었다. C-V측정으로부터 Mo2N/Mo이중층과 비저항이 6∼9Ω·㎝이고 결정면이 (100)인 P형 Si과의 일함수차 f%5는 약 -0.30ev 및 산화층에 존재하는 고정전하밀도 Qss/q는 약 2.1x1011/cm를 얻었다. 인버터 한개당의 신호전달 지연시간을 측정하기 위해 다결정실리콘게이트 NMOS 제조공정을 웅용하여 45개의 인버터로 구성된 ring oscillator를 제작하였다. 본 실험에서 얻을 수 있었던 인버터 한개에 대한 신호전달지연시간은 약 0.8nsec였다.