• 한국세라믹학회지
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• 제32권10호
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• pp.1147-1161
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• 1995

When ceramic membrance was made from metal salt solution in place of metal akoxide solution, crack free and good adhesion to supporter was optimized for sol stability and good adhesion force. A starting sol was prepared from aluminum oxychloride aqueous solutjion in order to inhibit the grain growthof Al2O3 during heat treatment. The crack free dip coating can't be achieved in 1mol/ι zirconium oxychloride solution because of the high viscosity which interferes with the hydration copolymerization between Al3+ ion and Zr4+ ion. Thus Al2O3-ZrO2 sol stability and viscosity for dip coating was effective when 0.01 mol/ι zirconium oxychloride was added. The minimizing of crack and achieving better adhesion to the supporter wa obtained by microwave drying, surfactant addition and ultrasonic dip coating in wet atmosphere. The result seems to minimize the capillary force and improve the adhesive ability to supporter during the process. Where the average pore size of Al2O3-ZrO2 ultrafilter ceramic membrane measured 17 Å by the BET method and observed γ-Al2O3 phase with tetragonal zirconia after firing at 700℃.

• 자원리싸이클링
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• 제9권2호
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• pp.33-39
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• 2000

생물여과법에 의한 유해성 유기물 제거용 저밀도 담체로 사용하기 위하여 석탄회를 출발물질로 이용하여 세라믹 담체를 제조하였다. 석탄회에 기공 조절용 및 탄소함량 조절용으로 밀가루를 첨가하여 약환원성 분위기를 유지하여 $1200^{\circ}C$에서 소결한 결과 1.6~1.8 g/$\textrm{cm}^3$의 겉보기 밀도를 얻을 수 있었다. 소결 시 공기를 차단하고 급속히 승온하여 시편 조성의 일부를 환원시킴으로써 액상을 형성할 수 있었으며, 이렇게 형성된 액상은 시편의 표면부근에 폐기공을 형성하여 밀도를 낮추었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.605-609
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• 2001

Low density ceramic supporter was prepared by using fly ash as a starting material for the application to the biological aerated filter (BAF) system, and the effect of additives and sintering atmosphere on the apparent and bulk density of the carrier was examined. Borax, Na$_2$O and glass powders were added to produce liquid phase. The density of the supporter decreased as the amount of borax increased. The bulk density of 0.79 g/㎤ and the apparent density of 1.10 g/㎤ were obtained when the fly ash with 15% of borax was sintered at 116$0^{\circ}C$ for 15 minutes. The density also decreased as the plate glass powders past through 22${\mu}{\textrm}{m}$ size were mixed. When the fly ash with 12% of grass powder was sintered at 128$0^{\circ}C$ for 10 minutes, the bulk and apparent density were 0.90g/㎤ and 1.00 g/㎤, respectively. Apparent density of 1.6~1.8g/㎤ was obtained when the fly ash was sintered at 120$0^{\circ}C$ in a weak reducing atmosphere. By maintaining the reducing atmosphere and sintering at a high heating rate, the liquid phase was farmed from the reduced composition of fly ash. This resulted in the formation of closed pores that enabled the low apparent density.

• 자원리싸이클링
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• 제9권2호
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• pp.40-45
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• 2000

석탄회를 출발물질로 사용하고 봉사 및 유리를 첨가하여 저밀도 세라믹 담체를 제조하였다. 또한 성형체의 초기 기공율을 높이기 위하여 밀가루를 30wt% 첨가하였다. 봉사를 첨가함에 따라 겉보기 밀도 및 벌크 밀도가 낮아졌고, 석탄회에 대하여 15wt%의 붕사를 첨가한 결과 $1160^{\circ}C$에서 15분 소결하여 벌크 밀도 $0.79g/\textrm{cm}^3$, 겉보기 밀도 $1.10g/\textrm{cm}^3$인 담체를 얻을 수 있었다. 판유리를 분쇄한 후 212 이하로 체가름한 유리 분말을 첨가하면 붕사와 마찬가지로 밀도가 낮아졌으며, 12wt% 첨가하여 $1280^{\circ}C$에서 10분간 소결한 결과 벌크 밀도 $0.90g/\textrm{cm}^3$, 겉보기 밀도 $1.00g/\textrm{cm}^3$를 얻을 수 있었다.

• 한국세라믹학회지
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• 제43권10호
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• pp.613-618
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• 2006

Graphite is suitable materials as a moderator, reflector, and supporter of a nuclear reactor because of high tolerance to the high temperature and neutron irradiations. Because graphite is so weak to the oxidation, its oxidation study is essentially demanded for the operation and design of the nuclear reactor. This work focuses on the effect of the surface oxidation of graphite according to the surface treatment. With thermogravimeter (TG), oxidation characteristics of the isotropic graphite are measured at the three temperature areas, and oxidation ratio and amounts are estimated as changing the surface roughness. Furthermore, the polished graphite surface produced fom the surface treatment is investigated with the Raman spectroscopic study. Oxidation behaviors of the surface are also evaluated as elimination the polished layer by washing with strong sonication.

• 한국경제지리학회지
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• 제18권4호
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• pp.556-572
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• 2015

이천 도자기 산업공간은 전통도자기를 재현 및 계승하는 전승도예 공간과 대학 도자공예 교육에 기반을 둔 현대도예 공간이 혼재되어 나타나 이원적 공간구조를 형성하고 있다. 따라서 본 연구는 이천 도자기 산업의 발달경로와 네트워크 실태 분석을 통해 전승도예와 현대도예의 이원적 공간구조를 분석하고자 하였다. 그 결과, 첫째 이천 도자기 산업공간은 점차 전승도예 공간에서 전승-현대도예의 이원적 공간으로 이행하고 있으며, 전승도예의 발달경로는 점차 쇠퇴하는 한편, 기존의 전승도예 발달경로를 기반으로 새로운 현대도예 발달경로가 창출되어 점차 이천 지역에 뿌리를 내리고 있다. 둘째, 전승도예와 현대도예는 기업 간 관계와 기업 외 관계 측면에서 상이한 양상을 띤다. 셋째, 정부는 대학교와 이천 도자기 업체(주로 전승도예 업체)간 기술협력 및 공동연구가 이루어질 수 있도록 재정적 행정적 지원 역할과 네트워크 중개 역할을 수행하고 있다.

• 한국전기전자재료학회논문지
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• 제25권10호
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• pp.766-772
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• 2012

Spring supported piezoelectric cantilever structures (SPCS) were fabricated for vibration-based energy harvester application. We selected four elastic springs (A, B, C, and D type) as cantilever's supporter, each elastic spring has a different spring constant (S). The C type of SPCS ($S_C$: 4,649 N/m) showed a extremely low resonance frequency of 81 Hz along with the highest power output of 38.5 mW while the A type of SPCS ($S_A$: 40,629 N/m) didn't show a resonance frequency while. Therefore, it is considered that the lower spring constant lead to a lower resonance frequency of the SPCS. In addition, a tip mass (18 g) at one end of the SPCS could further reduce the resonance frequency without heavy degradation of power output.

• 한국세라믹학회지
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• 제45권1호
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• pp.36-42
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• 2008

Carbon/$TiO_2$ composite photocatalysts were thermally synthesized with different mixing ratios of anatase to phenol resin through an ethanol solvent dissolving method. The XRD patterns revealed that only anatase phase can be identified for Carbon/$TiO_2$ composites. The diffraction peaks of carbon were not observed, however, due to the low carbon content on the $TiO_2$ surfaces and the low crystallinity of amorphous carbon. The results of chemical elemental analyses of the Carbon/$TiO_2$ composites showed that most of the spectra for these samples gave stronger peaks for carbon and Ti metal than that of any other elements. The BET surface area increases to the maximum value of $488\;m^2/g$ with the area depending on the amount of phenol resin. From the SEM images, small $TiO_2$ particles were homogeneously distributed to a composite cluster with the porosity of phenol resin-based carbon. From the photocatalytic results, the MB degradation should be attributed to the three kinds of synergetic effects, such as photocatalysis, adsorptivity, and electron transfer by light absorption between supporter $TiO_2$ and carbon.

• 한국세라믹학회지
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• 제45권4호
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• pp.196-203
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• 2008

Metal-carbon/$TiO_2$ composite photocatalysts were thermally synthesized through the mixing of anatase to metal(Cu, Zn) containing phenol resin in an ethanol solvent coagulation method. The BET surface area increases, with the increase depending on the amount of metal salt used. From SEM images, metal components and carbon derived from phenol resin that contains metal was homogeneously distributed to composite particles with porosity. XRD patterns revealed that metal and titanium dioxide phase can be identified for metal-carbon/$TiO_2$ composites, however, the diffraction peaks of carbon were not observed due to the low carbon content on the $TiO_2$ surfaces and due to the low crystallinity of the amorphous carbon. The results of a chemical elemental analysis of the metal-carbon/$TiO_2$ composites showed that most of the spectra for these samples gave stronger peaks for C, O, treated metal components and Ti metal compared to that of any other elements. According to photocatalytic results, the MB degradation can be attributed to the three types of synergetic effect: photocatalysis, adsorptivity and electron transfer, according to the light absorption between the supporter $TiO_2$, metal species, and carbon layers.

• 세라미스트
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• 제21권3호
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• pp.283-292
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• 2018

Here, we introduce various type of inorganic nanostructure synthesized with functional nanoparticles and silica. From two decades ago, functional inorganic nanoparticles have been synthesized and highlighted, now we moved to next level of wet-chemical synthesis. By integrating functional nanoparticles with silica, we were able to synthesize multi-functional nanostructure, which expand the applications of nanoparticles to catalyst, drug carrier, sensors. In this context, silica has been spotlighted due to its versatility. Silica has highly biocompatible, relatively transparent and stable under harsh conditions. Thus it can be used as good supporter to synthesize complex multi-functional nanostructure when mixed with other functional nanoparticles. A various shape of complex nanostructures have been synthesized including core-shell type, yolk-shell type and janus type etc. In this paper, we have described the purposes of synthesizing silica noncomplex and various case studies for biomedical applications and self-assembly.