• Journal of Microbiology and Biotechnology
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• 제6권3호
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• pp.189-193
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• 1996

Submicron-sized polymeric particles (SSPP) were used to remove nucleic acids and endotoxins from cell lysates. The positively charged SSPP selectively adsorb nucleic acids and endotoxins and form complexes with them. The complexes can be easily removed by sedimentation or centrifugation. The removal of nucleic acids and endotoxins using SSPP also can be accomplished in the presence of cell and cell debris. Therefore, nucleic acids and endotoxins can be removed in an initial step of the down-stream processes. In bakers yeast and E. coli lysate systems, the level of DNA could be reduced more than three orders of magnitudes and endotoxins more than seven orders of magnitudes concurrently willi the cell debris removal process using SSPP.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.253-256
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• 2002

$Gd_2O_3$:Eu phosphor particles were prepared by largescale ultrasonic spray pyrolysis process. The morphological control of $Gd_2O_3$:Eu particles in spray pyrolysis was performed by adding polymeric precursors into spray solution containing nitrate salts. The effect of composition and amount of polymeric precursors on the morphology, crystallinity, and photoluminescence characteristics of $Gd_2O_3$:Eu particles was investigated. The influence of chain length of PEG on the morphology and photoluminescence intensity was investigated. $Gd_2O_3$:Eu particles prepared from aqueous solution containing no polymeric precursors had a hollow structure and rough surfaces after annealing process. The phosphor particles prepared from solution containing 0.1M CA and 0.lM PEG with high molecular weight as 1,500 had a spherical and filled morphology and the highest photoluminescence intensity, which was 48% higher than that of the $Y_2O_3$:Eu commercial product.

• 한국재료학회지
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• 제13권3호
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• pp.180-184
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• 2003

Ce-doped $Y_2$SiO$_{5}$ phosphor particles of spherical morphology, fine size, high crystallinity and high photoluminescence (PL) intensity were prepared by spray pyrolysis. When nitrate precursor solution is adopted, hollow particles were formed by uneven drying rate between surface and inside of droplet. Citric acid and ethylene glycol were introduced as polymeric precursor to control the morphology of particles. When polymeric solution is adopted, polymeric chain is formed by the esterification reaction between carboxyl and hydroxy groups of citric acid and ethylene glycol, and considered as controlling the drying characteristics of droplet. $Y_2$$SiO_{5}$ :Ce phosphor particles prepared from polymeric precursor solution were spherical, filled, fine size and not agglomerate before and after post heat treatment. The optimum doping concentration of cerium was 0.5 mol% of overall solution concentration. The optimum amount of TBOS of high PL intensity and pure crystallinity of X2-type $Y_2$$SiO _{5}$ was 105% of stoichiometric amount. The PL intensity of $Y_2$X$/_{5}$ :Ce phosphor particles prepared using the polymeric precursor solution was 164% of that of the nitrate precursor solution due to homogeneous composition and good morphology.y.

• Korean Chemical Engineering Research
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• 제43권1호
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• pp.80-84
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• 2005

초음파 분무 열분해 공정에 의해 나노 크기의 $Y_2O_3:Eu$ 형광체 분말들을 합성하였다. 고분자 전구체와 융제로 사용되어진 리튬 탄산염이 나노 크기의 $Y_2O_3:Eu$ 형광체의 형태 및 발광 특성에 미치는 영향에 대해 조사하였다. 고분자 전구체와 융제를 동시에 사용했을 때 분무 열분해 공정에 의해 제조된 구형의 마이크론 크기의 분말들은 고온의 후열처리 과정에서 나노 크기의 분말로 전환되었다. $Y_2O_3:Eu$ 형광체의 평균 크기는 분무용액에 첨가되어지는 고분자 전구체와 융제인 리튬 탄산염의 첨가량 및 분무 열분해 공정의 반응기 온도에 많은 영향을 받았다. 고농도의 고분자 전구체를 함유한 분무용액으로부터 고온의 반응기에서 합성되고, $1,000^{\circ}C$ 이상에서 후열처리한 나노크기 $Y_2O_3:Eu$ 분말들은 진공자외선 하에서 좋은 발광 특성을 나타내었으며, 고상 공정에 의해 합성된 상용의 $Y_2O_3:Eu$ 형광체와 비슷한 발광 세기를 가졌다.

• Bulletin of the Korean Chemical Society
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• 제18권9호
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• pp.952-957
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• 1997

Modified polymeric composite electrodes having highly dispersed CuO particles through the electrode matrix were prepared for LCEC or flow injection analysis of carbohydrates. The composite electrodes were prepared by incorporating carbon black and highly dispersed copper oxide particles in polystyrene matrix cross-linked with divinylbenzene. The analytical characteristics of the electrodes for LCEC and flow injection analysis of carbohydrates were evaluated. Improved performance in LCEC and flow injection analysis of carbohydrates is demonstrated in terms of sensitivity, reproducibility, stability and surface renewability. It was possible to get improved performance of the electrodes as well as adaptability of the electrodes for practical applications by employing highly dispersed catalyst particles through the electrode matrix and robust polymeric electrode matrix.

• 공학논문집
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• 제6권2호
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• pp.5-10
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• 2004

• Bulletin of the Korean Chemical Society
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• 제34권9호
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• pp.2747-2752
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• 2013

Surface modification of colloidal silica nanoparticles without disrupting the electric double layer of nanoparticles is a major challenge. In the work, silane was employed to modify colloidal silica nanoparticles without inducing bridge flocculation obviously. The effect of pH value of the silica sol, the amount of silane in feed, and reaction temperature on the graft amount and the final size of modified particles was investigated. The increased weight loss by TG and the appearance of $T_2$ and $T_3$ except for $Q_2$ and $Q_3$ signals by CP/MAS $^{29}Si$ NMR of the modified samples verified the successful grafting of silane. The graft amount reached 0.57 mmol/g, which was slightly lower than theory value, and the particle size remained nearly the same as unmodified particles for acidic silica sol at the optimum condition. For alkaline silica sol after modification, aggregates composed of several nanoparticles connected together with silane moleculars as the bridge appeared.

• 폴리머
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• 제33권4호
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• pp.353-357
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• 2009

분무건조는 약물의 입자 제조에 널리 사용되고 있는 효과적이고 안정적인 공정 중 하나이다. 과거 분무건조의 방법에서는 입자의 응집을 조절하기 쉽지 않았으며, 크기 조절에도 많은 어려움을 겪어 왔다. 특히 고분자 입자의 제조는 저분자 유기물질인 식품, 의약원료 등과 비교하여 상대적으로 제조하기 어려운 면이 있었다. 본 연구에서는 기존의 분무건조기를 개조하여 노즐에 전기장을 외부에서 가해 줌과 동시에 동축 이중 노즐을 사용하여 고분자 입자의 제조를 시도하였다. 내부 고분자 물질로는 폴리에틸렌글리콜과 폴리락타이드코글리코라이드를, 외부 물질로는 락토오스를 사용하였다. 그 결과 전기장을 사용하지 않는 분무건조에 비해 비교적 일정한 크기와 모양을 제조할 수 있었으며, 입자 간의 응집을 줄일 수 있음을 확인하였다. 전기분무건조된 PLGA 분말은 주로 $2{\sim}5{\mu}m$ 기인 둥근 모양의 입자로 구성되었다.

• 한국기계가공학회지
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• 제14권5호
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• pp.126-133
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• 2015

Recently, there has been demand for polymeric porous membranes in various fields, such as environmental engineering, pharmaceutics, tissue engineering, drug delivery, biology, and fuel cells. In this study, it is proposed that a polymer particle-based porous membrane can be fabricated using electrospraying and sintering processes. Electrospraying can fabricate polymeric particles with diameters ranging from several micrometers to tens of nanometers without the cumbersome particle aggregation problem. Additionally, the particles can be sintered through thermo-compression under the glass transition temperature. In this study, a polymethyl methacrylate particle-based porous membrane with an average pore size of less than 500 nm is fabricated using the proposed method.

• 한국세라믹학회지
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• 제32권8호
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• pp.901-908
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• 1995

In aqueous slurry processing of silicon nitride, the interaction of dispersant and binder used as polymeric processing additives on the silicon nitride particle surface was studied to identify the effect of these processing polymeric additives on the ceramic powder processing. The adsoprtion isotherm study of anionic organic molecule as dispersant and nonionic organic molecules as binder of silicon nitricde was studied to investigate the effect of these processing organic additives on the physicochemical properties of silicon nitride particles. As anionic molecule adsorbed onto silicon nitrice surface, the IEP of silicon nitride shifted toward acidic pH and changed the stability of silicon nitride particle. However, the adsorption of binder as nonionic organic molecule onto silicon nitride surface did not changed the IEP but caused the decrease of electrostatic potentials of silicon nitride. These distinctive adsorption behaviors of organic additives on silicon nitride particles can be closely correlated to the stability of silicon nitride particles suspended in aqueous media.