• 한국세라믹학회지
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• 제41권7호
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• pp.503-507
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• 2004

The importance of porous ceramics has been increasingly recognized and adequate strength of porous ceramics is now required for structural applications. Porosities of porous ceramics act as flaws in inner volume and outer surface which result in severe strength degradation. The effect of pore structure, however, on strength and reliability of porous ceramics has not been clearly understood. We investigate the relationship between pore structure and mechanical properties using a sphere indentation on bilayer structure, porous ceramic top layer with soft polymer substrate. Porous alumina and silica were prepared to characterize the isolated pore structure and interconnected pore structure, respectively. The porous ceramic with 1mm thickness were bonded to soft polycarbonate substrate and then fracture strengths were estimated from critical loads for radial cracking of porous ceramics during sphere indentation from top surface. This simple and reproducible technique provides Weibull modulus of strength of porous ceramics with different pore structure. It shows that the porous ceramics with isolated pore structure have higher strength and higher Weibull modulus as well, than those with interconnected pore structure even with the same porosity.

• Bulletin of the Korean Chemical Society
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• 제34권11호
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• pp.3357-3361
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• 2013

Alumina microfibers with porous structures were prepared through hydrothermal reaction, and then used to modify the surface of carbon paste electrode (CPE). After modification with alumina microfibers, the electrochemical activity of CPE was found to be greatly improved. On the surface of alumina microfibers-modified CPE, the oxidation peak current of salvianolic acid B, a main bioactive compound in Danshen with anti-oxidative and anti-inflammatory effects, was remarkably increased compared with that on the bare CPE surface. The influences of pH value, amount of alumina microfibers and accumulation time were studied. Based on the strong signal amplification effects of alumina microfibers, a novel electrochemical method was developed for the detection of salvianolic acid B. The linear range was from 5 ${\mu}gL^{-1}$ to 0.3 mg $L^{-1}$, and the detection limit was 2 ${\mu}gL^{-1}$ (2.78 nM) after 1-min accumulation. The new method was successfully used to detect salvianolic acid B in ShuangDan oral liquid samples, and the recovery was over the range from 97.4% to 102.9%.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.315-318
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• 2002

Light emitting thin film structures based on organic luminophors embedded in porous alumina matrixes are discussing. The optical properties of the luminophors in a matrix differ greatly from their properties in usual crystalline state or in a solution and they depend on the concentration of luminophors molecules of up to 10-2 mol/l. Successful experiments on filling of pores with organic luminophors and the investigation of their luminescent and optical properties were carried out.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.364-365
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• 2006

One of the promising routes for producing highly ordered nanostructures is a template method using the porous alumina membrane (PAM). Because the PAM is mechanically, chemically, thermally stabile with highly ordered structure, many researchers have studied under various experimental conditions to fabricate nanostructures. We present the information on the fabrication of about 300 nm nano-mask which have important applications for various patterned nanostructures.

• 한국세라믹학회지
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• 제45권10호
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• pp.584-588
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• 2008

Porous hydroxyapatite(HA) and HA-coated porous $Al_2O_3$ possessing pore characteristics required for bone substitutes were prepared by a slurry foaming method combined with gelcasting. The HA coating was deposited by heating porous $Al_2O_3$ substrates in an aqueous solution containing $Ca^{2+}$ and ${PO_4}^{3-}$ ions at $65{\sim}95^{\circ}C$ under ambient pressure. The pore characteristic, microstructure, and compressive strength were investigated and compared for the two kinds of samples. The porosity of the samples was about 81% and 80% for HA and $Al_2O_3$, respectively with a highly interconnected network of spherical pores with size ranging from 50 to $250{\mu}m$. The porous $Al_2O_3$ sample showed much higher compressive strength(25 MPa) than the porous HA sample(10 MPa). Fairly dense and uniform HA coating(about $2{\mu}m$ thick) was deposited on the porous $Al_2O_3$ sample. Since the compressive strength of cancellous bone is $2{\sim}12$ MPa, both the porous HA and HA-coated porous $Al_2O_3$ samples could be successfully utilized as scaffolds for bone repair. Especially the latter is expected suitable for load bearing bone substitutes due to its excellent strength.

• 한국재료학회지
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• 제12권7호
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• pp.533-539
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• 2002

Porous anodic aluminum oxide layer for nano templates was prepared in acidic solutions. In order to investigate effects of 2nd anodization on ordered formation behaviors of the porous oxide layers, electrochemical and microstructural studies were performed, primarily using TEM, FE- SEM, AFM, and Ultramicrotomy. The pore diameter of the anodic oxide layer increased approximately linearly with increasing voltages, and to the contrary, the pore density decreased. It was shown that 2nd anodizing on the cell base after dissolving 1st anodic oxide layer was remarkably effective for forming ordered array of the pores, comparing with the case for 1st anodization only. And for controlling the diameter of pores, widening method by chemical dissolution seemed more practical than by electrochemical methods.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2000년도 추계학술대회 및 발표대회 강연 및 발표논문 초록집
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• pp.49-49
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• 2000

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2003년도 춘계총회 및 연구발표회 초록집
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• pp.195.2-195
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• 2003

• 한국진공학회:학술대회논문집
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• 한국진공학회 2003년도 제24회 학술발표회 초록집
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• pp.105-105
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• 2003

• 한국결정성장학회지
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• 제7권2호
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• pp.324-333
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• 1997

초음파 분무 열분해 알루미나 분체로부터 $1600^{\circ}$~$1700^{\circ}C$ 범위의 소정 온도에서 소결한 다공질 시편의 상대밀도는 80~92%이다. 소결 온도 및 유지 시간이 길어지면 과대 입성장을 일으킨다. 소결 중의 미세 구조 발달을 이미지 분석하였다. 초음파 분무 열분해 알루미나 분체의 소성시 결정립 성장 동력학에 대한 연구로부터 정상 입성장 결정립 성장 활성화 에너지는 386.77 kJ/mol이다.