본 연구에서 처리수를 이용한 주기적인 역세척은 세라믹 정밀여과에 의한 고도정수처리 시스템에서 막오염을 저감하고 투과선속을 향상시키고자 수행되었으며, 물 역세척 주기(FT) 및 시간(BT)의 영향과 최적 운전조건을 규명하고자 하였다. FT의 영향을 알아보기 위해 일정한 BT 3초에서 FT를 30∼120초로 변화시켰고, BT 영향 실험에서 일정한 FT 120초에서 BT를 3∼12초로 변화시켰다. 그리고 다른 운전변수인 막간압력차는 1.52 bar, 물 역세척 압력 0.98 bar, 유입유량 0.5 L/min, 공급액의 온도 20℃로 일정하게 유지하였다. 그 결과, 일정한 BT 3초에서 본 실험 범위의 최적 FT는 30초로, 이것은 빈번한 역세척이 막오염의 저감에 더 효과적임을 의미한다. 그러나 너무 짧은 BT로 인하여 FT의 영향은 크지 않았다. 한편, 일정한 FT 120초에서 BT가 증가함에 따라 막오염에 의한 저항(Rf)은 감소하고 투과선속(J)과 무차원화한 투과선속 (J/Jo)은 증가하는 경향을 나타내어, 최대 BT인 12초에서 가장 많은 총여과부피(VT)를 얻을 수 있었다.

본 연구에서는 칼슘 이온 제거를 위해 칼슘용액에 임계미셀농도(CMC) 이상으로 음이온계면활성제인 sodium dodecyl sulfate (SDS)를 주입하여 미셀을 형성한 후, 미셀 표면에 칼슘 이온의 흡착 또는 결합으로 형성된 응집체들을 2종류의 세라믹 분리막으로 배제하였다. 그 결과, 99.98% 이상 칼슘 배제율을 보였다. 또한 본 실험범위에서 TMP가 증가할수록 막오염(Rf)은 증가하는 경향을 보였지만, 구동력의 증가로 인해 총여과부피(VT) 및 무차원한 투과선속(J/Jo), 투과선속(J) 역시 증가하였다. 또한 세라믹 분리막에 대하여 주기적 질소 역세척을 실시할 경우, 질소 역세척 시간(BT) 및 여과 시간(FT), 즉 역세척 주기의 영향을 조사하였다. 그 결과, NCMT-6231 (평균기공 0.07 μm) 및 NCMT-7231 (0.10 μm) 분리막의 최적 BT는 각각 10초, 15초이었다. 또한, 최적 FT는 2종류 분리막 모두 5분으로, 빈번한 질소 역세척이 막오염을 효과적으로 감소시켰다. 한편 칼슘용액으로 실험하여 도출된 최적 운전조건을 두유 포장팩 세척수로 사용하고 있는 지하수에 적용한 결과, 2종류의 분리막 모두 칼슘을 99.98% 이상 제거할 수 있었다.

Ceramic pigments were developed by using 4 kinds of Brass scraps. Each Brass scraps were mixed with same weight-ratio of Husk ash, and fine-ground by Rotate ring mill(RRG-120, Armstech industrial. co. Ltd, Korea) after firing at 900℃, 1000℃ and 1100℃. As a result, analysis of particle size of synthetic pigments by particle size analyser, they are 3μm as average. The resulting pigments were characterized by using XRD, FT-IR, SEM Structure of the crystals are Zn2SiO4,, and ZnO, Cu2O, CuO, and cristobalite are existed and particles' shape are plate or needle. As a result of analysis of chemical composition by XRF, synthetic pigments have high SiO2 and CuO content and have SnO2, ZnO and NiO, too. 1wt%, 3wt% and 5wt% pigments were added in each lime glaze, lime-barium glaze and lime-magnesia glaze, and fired at oxidation and reducing atmosphere to figure hue in glazes out. As a result of analysis of color, chroma and brightness by UV, colors of glazes fired at oxidation atmosphere turned into green from sky blue, and colors of glazes fired at reducing atmosphere turned into pink and red.

1'0 develop an effi cient scaffold fo1' t issue-engineered bone 1'egene1'ation, we evaluated fully in terconnected globular porous bisphasic calcium-phosphate ceramics. Materials and Methods: Biphasic HA/TCP cera mic scaffolds having f띠 l y interconnected globular structure with small fenestrations adopting foaming method were p1'epared. They were evaluated by cytotoxici ty‘ cellular attachment. and theil‘ differentiation in vitro and the hi s tocompatibili ty, osteoconductivity. and ectopic os teoinductive capacity in 띠 vo ， respectively. They have average 400um s ized spherical pores and ave1'age 100um s ized inter connecting interpores with average 85% porosity. They r evealed comparable compression strength with cancellous bone. They were nontoxic and revealed no noxious effect on cellular proliferation and osteoblastic diffe re ntiation. The cul tured cells on scaffolds were well attacbed and proliferated in multi-layers. The increased surface in fully interconnected globular porous scaffold facilitated osteogenic repair by favored cell ular attachment and osteogenic differentia tion with good osteoconductivity. 1n addition. the scaffold-cell constructs induced favorable ectopic bone formati on These findings suggest that the fully interconnected globular porous biphas ic HA/ß -TCP ceramic scaffold formed by foaming method can be a promising bone substitute and a scaffold fo 1' tissue-engineered bone 1'egeneration

We evaluated the influence of internal macro- porous structure on tissue-engineered bone regeneration by cOll1paring the effi cien cy of scaffold-cell construct forll1ation and its bone induction activity. T매o types of macro-porous CMP cera rnic blocks having 400 um average pore s ize in an interconnected trabecular framework and interconnected globular structu1'e with small fenestrations were prepa1'ed, adopting sponge method and foaming method. respectively. They ware evaluated by cytotoxicity. cell ular attachment. and t heir differenti ation in vitro and the histocompatibility, osteoconductivity, and ectopic osteoinductive potenetial in vivo, respecti vely. Both scaffolds having either interconnected trabecu lar pOI‘es formed by sponge ll1ethod 0 1' fully interconnected globu lar pores formed by foam-based technology were no cyt otoxic and induced neither an immune nor an infl ammatory response regardless 0 1' geometry and manufacturing methods. The fu lly interconnected globul 81 porous scaffold showed more favora ble compression strength compared to the interconnected trabecualr porous scaffold (8.7 :tO. 5 MPa va 5. 5:t0. 5 MPa) . The increased surface in fully interconnected globular po1'ous scaffold facilitated osteogenic repall‘ by favored cellular attachment and osteogenic differentiation with good osteoconductivity. These results suggest that the fully interconnected globular porous structure be more sui table for both bone s ubstit ute and scaffold for t issue-engineered bone regeneration‘

본 연구에서는 경도 이온의 화학적 침전을 위하여 지하수에 과량의 Lime-Soda ash를 주입하여 플럭(floc)을 형성한 다음 침전과정을 십자흐름(Crossflow) 방식의 관형 세라믹 분리막을 이용한 한외여과(UF) 공정으로 대체하였다. 그 결과 두유 포장팩 세척수로 사용하고 있는 지하수의 총경도를 10 mg/L as CaCO3 이하로 감소시킬 수 있었다. 한편, TMP(Trans-membrane pressure) 및 유량 변화 실험에서 투과선속(Permeate flux, J) 및 무차원한 투과선속(J/JO) 변화를 조사하여, TMP 및 유량이 무기물로 형성된 응집 플럭에 의한 막오염에 미치는 영향을 알아보았다. 그 결과, 본 실험 범위에서 TMP 및 유량 변화가 막오염과 총경도 제거율에 미치는 영향은 거의 없었다.

  “Getting to market first” is extremely critical in this competitive business environment. The speed at which products are developed and released to market is tightly linked to profitability and market share. Many companies that have been very skeptical

본 연구에서는 2종류의 다채널 알루미나 세라믹 정밀여과막으로 호소수를 처리할 경우, 질소 역세척 시간(BT) 및 막간압력차(TMP) 영향과 최적운전조건을 규명하였다. 정상여과시간(FT)은 8분, 유량 2.0 L/min, 역세척 압력 2.0 bar로 고정하였고, BT는 10∼60초, TMP는 0.6~2.0 bar로 변화시켰다. 또한, 최적운전조건은 막오염에 의한 저항 (Rf), 무차원한 투과선속 (J/Jo), 투과선속 (J), 총여과부피VT의 측면에서 고찰하였다. 그 결과, 0.4 μm의 평균기공 크기를 갖고 있는 HC04 분리막의 최적 역세척 조건은 BT=10초, 1.0 μm의 평균기공인 HC10 분리막에서는 20초임을 알 수 있었다. 한편, TMP가 증가할수록 구동력의 증가로 보다 많은 VT를 얻을 수 있었다. 오염물질 제거율은 탁도(Turbidity) 95.4% 이상, 화학적 산소 요구량 (CODMn) 12.7∼20.1%, 암모니아성 질소(NH3-N) 0.0∼6.4%, 총질소 (T-N) 1.9∼4.6%, 총인 (T-P) 34.9∼88.4%의 제거 율을 보였다.

수화현상의 대표적 원인 생물인 남조류의 M. aeruginosa와 대조구로서 녹조류인 C. zofingiensis를 인공 배양하여 분말세라믹 투여에 따른 선택적 조류 제거 가능성에 대해 실험하였다. 0.05 mm의 분말세라믹을 투여에 따른 M. aeruginosa 및 C. zofingiensis의 침전효율은 각각 82와 63%였으며, 입자크기 0.1과 1 mm의 경우에서 는 M. aeruginosa는 각각 69와 34%, C. zofingiensis는

In this work, the dispersion behavior of particles in binary aluminum (Al)-copper (Cu) cast alloy was investigated with respect to Cu contents of 20 (hypoeutertic), 33 (eutectic) and 40 (hypereutectic) wt.%. In cases of hypo and hypereutectic compositions, SEM images revealed that the primary Al and phases were grown up at the beginning, respectively, and thereafter the eutectic phase was solidified. In addition, it was found that some of particles can be dispersed into the primary Al phase, but none of them are is observed inside the primary 6 phase. This different dispersion behavior of particles is probably due to the difference in the val- ues of specific gravity between particles and primary phases. At eutectic composition, particles were well dispersed in the matrix since there is few primary phases acting as an impediment site for particle dispersion during solidification. Based on the experimental results, it is concluded that particles are mostly dispersed into the eutectic phase in binary Al-Cu alloy system.

As a pa rt 0 1' the effort to develop a suitable scaffold for tissue-engineered bone regene ration, we modified calcium metaphosphate(CMP) ce ramic with 5 mol% Na20 or K20 to improve t he biodegradability and evaluated their effi ciency as a biodegr adable scaffold for ti ssue-engineered bone regeneration. The macroporous αiIP ceramic blocks incor porated with 5 mol% Na20 or K20 were prepa recl to have average pore size of 250 um in an inte rconnectecl framework structure The influ e nce of inco r pora tecl 5 mol% Na20 or K20 on cytotoxicity‘ cellular attachmont and t heir clifferentiation was evaluated by in vit ro analyzing sys tern. res pectively. The bioclegradability, histocompatibility, and osteogenic effect by cell-scaffolcl co nstruc ts were evalua ted by im plantation of them into subcutaneous pouches of SD-rats 0 1' SCID ITllce The incorporation of 5 mol% Na20 or K20 causecl clecrease of compressive strength without improving of biodegr adabili ty . The moclifi ed scaffolcls revea led no cy totoxic and excell ent biocompatability but osteogneic effect was recluced compa red to pure CMP ce ramic porous blocks . These res ul Ls s ugge::;t tha t the incorporation of 5 mol% Na20 0 1' K20 into pure CMP is not effective for improv ing effï ciency 0 1' scaffolcls fo1' tissue-engineered bone regeneration in terms of bioclegradabi li ty‘ physical s trength . a ncl osteogenic rege ne ra tive effect

Y-type barium ferrite was prepared by the glass-ceramic method. Glasses with composition of were prepared, and the precipitation behavior of Y-type ferrite from the glass matrix was investigated by heating glass specimens at various temperature. which is a precursor of M-type ferrite was precipitated at about 813 K and an unknown compound, phase X, was precipitated at about 850 K. M-type ferrite and Y-type ferrite started to form at about 923 K and 1103 K, respectively. The formation of Y-type ferrite was int erpreted as the result of the reaction of M-type ferrite with a melt of phase X.

Y-type barium ferrite ( Me=Zn, Co, Cu) expected as an electromagnetic wave absorber were prepared by the glass-ceramic method. The glasses with composition of were prepared. Single-phase powders of Y type barium ferrite were obtained with the composition . The shape of Y-type crystals depended strongly on the heating temperature and changed from a plate-like hexagon to a complex polyhedron with increasing heating temperature. Correlation was recognized between saturation magnetization and crystal shape. Electromagnetic wave absorption characteristics was affected by the saturation magnetization and crystal shape.

The perovskite- type oxide containing transition metals on the B-site show mixed (electronic/ionic) conductivity. These mixed-conductivity oxides are promising materials for oxygen permeating membranes. The main objective of this research work is to synthesize and characterization ceramic powders of the Sr-Co-Fe-O system for methane conversion using membrane reactor. SCFO powders were synthesized from the route was based on the complex method of combination of acid EDTA and citrate and shown be available by control efficient of synthesis to performed , moreover, it presented easy implementation, reproducibility and operation. Powder ceramic was characterized by XRD, microscopic optic, SEM and TG-DTA.

In this investigation, based ceramic composites were fabricated by in-situ reaction hot pressing using , TiC SiC powder as starting materials. The reaction synthesized composites by hot pressing at was found to posses very high relative density. The reaction synthesized composites comprise , , SiC and graphite by the reaction between TiC and . The newly formed and graphite was embedded both inside grain and at grain boundary . The mechanical properties of reaction synthesized -graphite composites were more enhanced compared to those of monolithic .