• 한국세라믹학회지
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• 제49권3호
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• pp.226-230
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• 2012

This paper presents a novel structure for a diesel particulate filter (DPF) with inclined gas paths, which was designed so that the gas paths offered a fluent flow of exhaust gases, and particulate matter (PM) was collected at pores formed in the body. The alumina porous filter was prepared by a conventional sintering process at $1200^{\circ}C$ for 2 h. Straight gas paths with $30^{\circ}$ of inclination from the gas flow direction were formed in the filter body. It is shown that this filter structure worked as a PM filter, in which 90.2% of soot filtration efficiency and 59.6 mbar of pressure drop were achieved.

• 한국세라믹학회지
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• 제36권2호
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• pp.220-224
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• 1999

질화규소 겔케스팅 공정제어를 위하여, MeOH의 첨가가 겔화유도시간과 성형체의 건조속도 및 기계적 특성에 미치는 영향에 대하여 조사하였다. 그 결과, 10~20 vol%의 MeOH 첨가에서 겉보기 겔화유도시간은 가장 크게 나타났으며, 이때의 건조속도는 약 25~40%의 증진효과를 나타내었다. 분산매에 대하여 40% MeOH 첨가 범위에서 성형체의 기계적 가공은 가능하였으나, 겔캐스팅 성형체의 상대밀도 및 강도는 다소 낮아졌다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권10호
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• pp.484-490
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• 2003

This paper describes with the stator analysis and design of a ring type ultrasonic motor. The design for piezoelectric ceramic and elastic body of stator were calculated by using the finite element method (FEM) that consider the resonance frequency, vibration mode and coupling efficiency. Namely, such results were acquired the calculation result of the piezoelectric ceramic thickness 0.5[mm], elastic body thickness 2.0[mm], resonance frequency 51.8[kHz], vibration mode 7 order and coupling efficient 12.5[%], the outer and inner diameter of vibrator 50[mm], 38[m]. On the basis of such result, the ring type ultrasonic motor was manufactured. Also for driving characteristics of ring type ultrasonic motor, 2-phase inverter was constructed. Then the propriety of this paper was established from comparision of the simulation and an experiment results of the ring type ultrasonic motor.

• 한국세라믹학회지
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• 제39권11호
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• pp.1048-1054
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• 2002

가소성 소지를 이용하여 세라믹을 성형하는 경우에 소지의 가소성 평가뿐만 아니라 이를 범위 내에서 제어하기 위하여도 가소성을 정량적으로 시험할 필요가 있다. 비록 많은 가소성 측정 장치들이 소개되기는 하였으나, 간편하게 정량적으로 측정할 수 있는 장치는 아직 없다. 본 연구에서는 바이카 침을 변형하여 허니컴 압출성형용 소지의 가소성을 간편하게 정량적으로 비교할 수 있는 장치를 만들었다. 이 장치를 사용하여 3가지 소지의 가소성을 조사하였다. 변형에 대한 저항의 측정에는 직경 2 mm 원주형 침을 사용하였고, 균열이 일어나기 전까지의 변형 량의 측정에는 직경 9.5 mm 구형의 침을 사용하였다. 측정결과 이 소지들의 가소성을 정량적으로 구분할 수 있었으며, 작업성을 평가하는데 유용하였다. 만약 적당한 직경의 원주형 및 구형의 침을 선택한다면 이 장치로 다양한 세라믹 소지의 가소성을 평가할 수 있을 것으로 보인다.

• 대한치과기공학회지
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• 제10권1호
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• pp.177-183
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• 1988

This paper aims to examine ceramic shade prescriptions for work authorizations in all its aspectclincal information, recording information, technical considerations, extended application, practical applications. The results are as follows : 1. The basic application provides essential data for ceramic veneer fabrication. 2.Three-dimensional information divides the space for body and enamel components. 3. The second body shade selection improves shade matching in the middle one-third of the tooth and enhences the appearance of the enamel component. 4. Ceramists are encouraged to recognize the influence each component has upon the total shade composition. 5. A format is established for recording clinical information. 6. The use of available ceramic systems is seemingly unlimited. The method presented provides flexisility for recording the most detailed shade information in simple graphic and verbal terms. 7. Technical simplification is a by-product of complete, precise work information.

• 한국전기전자재료학회논문지
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• 제28권6호
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• pp.384-389
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• 2015

In this paper, we fabricated ceramic body and sapphire wafer in order to develop a hydraulic pressure sensor with high sensitivity and high temperature stability. The sapphire wafer was adopted with a membrane of capacitance ceramic pressure sensor. The capacitance value of the sensor for the finite element analysis(FEM) showed a linear pressure characteristics. Membrane was processed with a diameter of 32.4 mm and a thickness of 1 mm by using alumina powders. Ceramic body was processed with a diameter 32.4 mm and a thickness 5 mm. The capacitance pressure sensor was made with high heat treatment of the ceramic body and the sapphire wafer. Initially capacitance of the pressure sensor was 50 pF and a capacitance of 110 pF was measured from 5 bar pressure. Output voltage of 5 V was appeared at 5 bar pressure.

• 한국세라믹학회지
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• 제31권12호
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• pp.1507-1512
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• 1994

High strength cement hardened body was prepared by ordinary portland cement, silica-fume, super-plasticizer and the industrial by-product powder such as tailing, paper sludge ash and granulated slag. These raw materials were mixed and formed with w/c=0.18. The cement hardened body is cured in the autoclave at 18$0^{\circ}C$, 10atm. These admixtures made the compressive strength of all specimens develope by 170~230%. The highest compressive strength could be obtained by 236 MPa when mix composition was 14 wt% of silica-fume and 26 wt% of granulated slag. The compressive strength increased with decreasing the average pore size and the amount of the poe over the size of 50 nm by which the appearance of high compressive strength of the cement hardened body were mainly influenced. In the result, the hydration products were C-S-H, tobermorite and ettringite and it was realized that the reason why the cement hardened body became dense and revealed the higher strength was that those hydrates were formed inside of the pore and filled in it and the unhydrated materials played the role of an inner-filler.

• 한국세라믹학회지
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• 제49권5호
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• pp.438-441
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• 2012

Abalone shell is a high strength and light weighted ceramic composite material, which is composed of $CaCO_3$ platelet and protein. Microstructure of abalone shell has a matrix structure that is similar to the bricks and mortar. The technology inspired from nature which consumes low energy at low temperature is called bioinspired technology. In this study, to make high strength and light weighted ceramic composite materials using bioinspired technology, porous green body was prepared with $Al_2O_3$ platelet. PMMA was infiltrated into the porous green body, then warm pressed to eliminate pores present in the composite. The microstructure of the composite was observed with FESEM, and the mechanical/thermal properties were measured.

• 한국세라믹학회지
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• 제24권2호
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• pp.155-160
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• 1987

본 연구는 제2보에서 합성한 $ZrSiO_4-Cd(SxSe_{1-x})$ 채료의 실용성을 조사하기 위하여 행하였다. 기존의 유명회사 제품의 채료와 본 합성채료를 비교 검사하였다. 우선 각각의 채료에 Frit를 적당한 비로 혼합하고 일정조성의 Tile에 시유하여 각각다른 온도(850-120$0^{\circ}C$)에서 소성한 다음 colorimeter를 사용하여 XYZ 주파장에 따른 색도도를 측정하였다. 또한 Munsell 계의 ISCC-NBS 색명법을 적용하여 색을 정량화 시킴으로서 채료의 적응성을 연구하였다. 그 결과 $ZrSiO_4-Cd(SxSe_{1-x})$ 채료는 V나 P 계통의 여타 채료와 같이 Frit 대 Stain의 비가 9:1의 최소비로 사용이 가능하며 100$0^{\circ}C$의 높은 온도에서도 밝은 적색으로 재현 될 뿐만 아니라 내산성이 강하고 고온에서 적응성이 있음을 확인하였다.

• 한국세라믹학회지
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• 제52권1호
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• pp.33-40
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• 2015

Onggi, described as a 'breathing' type of pottery' has significantly influenced the traditional food culture of Korea. It is known that Onggi is an optimal type of storage for fermented foods such as soy sauce, salted seafood, and Kimchi, as air or liquid can penetrate through the body of this material. These foods gain flavor due to the breeding of aerobic bacteria at the beginning of the fermentation process. In this study, Onggi materials from five regions, Gangjin, Yeoju, Ulsan, Yesan, and Jeju, were collected and analyzed to determine their chemical and physical properties before and after sintering. The differences in the raw materials of other mining regions are examined in terms of their chemical and mineralogical compositions, specific surface area, particle size, and particle distribution. Among them, the Gangjin raw material has the greatest mean particle size of $92.29{\mu}m$, as well as the widest particle size distribution. Differences in the levels of $SiO_2$ and $Fe_2O_3$ are shown among Onggi raw materials. However, the crystalline phases formed after sintering are identical, except for the Jeju samples. At all sintering temperatures tested here, Gangjin Onggi showed the greatest porosity, leading to complete air permeation through the body within 90 minutes. These results taken together indicate that air permeation is strongly related to the pore structures in the Onggi body. This is assumed to affect the fermentation behavior.