• Journal of the Korean Wood Science and Technology
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• 제45권3호
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• pp.288-296
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• 2017

본 연구에서는 분무건조 조건 및 계면활성제 첨가에 따른 리그노셀룰로오스 나노피브릴(lignocellulose nanofibril, LCNF)의 분무건조 수율 및 건조 LCNF의 형태학적 특성, 치수분포 및 수재분산성을 조사하였다. 원료로는 약 70-300 nm 직경을 지니는 섬유상의 LCNF를 사용하였으며, 분무건조 LCNF는 rod형 파티클의 형태학적 특성을 보였다. $140^{\circ}C$ 온도조건에서의 분무건조 수율이 가장 높았으며, 분무건조 LCNF의 입자크기 또한 가장 작았다. LCNF 현탁액의 농도가 감소할수록 또한 송풍량이 증가할수록 분무건조 수율 및 입자크기가 증가하였다. 또한, 계면활성제의 첨가로 건조 수율을 향상시킬 수 있었으며, 첨가 비율이 증가할수록 평균입자크기가 감소하였다. 건조 LCNF의 입자 크기가 감소할수록, 물에서의 재분산성이 향상되었으며, 수현탁액의 여수시간이 증가하였다.

• 한국입자에어로졸학회지
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• 제12권3호
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• pp.65-72
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• 2016

Nanoporous $SiO_2$ particles containing different pore volume and size were prepared from silicic acid by a spray pyrolysis. The pore size, pore volume and particle size could be controlled with varying the precursor concentration, reaction temperature, and amount of organic templates such as Urea and poly ethylene glycol (PEG). The pore size distribution, pore volume and specific surface area of as-prepared particles were analyzed by BET and BJH methods, and the average particle sizes were measured by a laser diffraction method. The nanoporous $SiO_2$ particles ranged $0.6-0.9{\mu}m$ in diameter were successfully synthesized and the average particle size increased as the silicic acid concentration increased. The morphology of nanoporous $SiO_2$ particles was spherical and pores ranged 1 - 40 nm in diameter were measured in the particles. In case of Urea added into silicic acid, it showed no much difference in the morphology, pore size and pore volume at different Urea concentration. On the other hand, when PEG was added, it was clearly observed that pore diameter and pore volume of the particles surface increased with respect to PEG concentration.

• 폴리머
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• 제28권2호
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• pp.128-134
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• 2004

비타민E 아세테이트를 봉입하고 있는 셀룰로오스 나노입자는 개선된 자발적 유화확산 방법을 이용하여 제조하였다. 셀룰로오스 나노입지는 셀룰로오스 유도체와 비타민E 아세테이트를 아세톤/에탄올 혼합유기 용매로 용해한 다음 초음파 발생장치를 이용하여 폴리(옥시에틸렌 솔비탄 모노올레이트) 용액에 분산하여 제조하였다. 입자크기와 비타민 E 아세테이트의 봉입률은 광산란 장치와 UV 분광계를 이용하여 각각 측정하였다. 나노입자의 안정성은 상온에서 30일간 입자크기 변화를 통해 비교하였고 입자의 형태는 주사전자 현미경을 통해 관찰하였다. 결과적으로 제조된 나노입자의 형태는 구형인 것을 관찰하였고, 상온에서 30일간 입자크기 변화가 없었다. 가장 좋은 셀룰로오스 나노입자의 제조 조건은 1% w/v 니트로셀룰로오스와 8% w/v 폴리(옥시에틸렌 솔비탄 모노올레이트)를 사용하였을 경우이고, 이때 나노입자의 크기는 65nm, 비타민E 아세테이트의 봉입률은 71%의 값을 나타내었다.

• 한국재료학회지
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• 제23권2호
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• pp.89-97
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• 2013

The study of grinding behavior characteristics on aluminum powders and carbon nano tubes (CNTs) has recently gained scientific interest due to their useful effect in enhancing advanced nano materials and components, which significantly improves the property of new mechatronics integrated materials and components. We performed a series of dry grinding experiments using a planetary ball mill to systematically investigate the grinding behavior during Al/CNTs nano composite fabrication. This study focused on a comparative study of the various experimental conditions at several variations of rotation speeds, grinding time and with and without CNTs. The results were monitored for the particle size distribution, median diameter, crystal structure from XRD pattern and particle morphology at a given grinding time. It was observed that pure aluminum powders agglomerated with low rotation speed and completely enhanced powder agglomeration. However, Al/CNTs composites were achieved at maximum experiment conditions (350 rpm, 60 min.) of this study by a mechanical alloy process for Al/CNTs mixed powders because the grinding behavior of Al/CNTs composite powder was affected by addition of CNTs. Indeed, the powder morphology and crystal size of the composite powders changed more by an increase of grinding time and rotation speed.

• 한국세라믹학회지
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• 제32권4호
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• pp.462-470
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• 1995

The characteristics of spray-dried granules are important for dry pressing operation since they have great influences on die-filling, compaction ratio, and resulting green microstructure. An attempt was made to control granule morphology and the packing structure of fine Si3N4 particles in granules by adjusting suspension property. Mercury porosimetry was used to characterize the pore structures of both granules and green compacts. Finally, the effects of particle packing structure in granules and green microstructure on sintering behavior were investigated.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2000년도 춘계학술대회 논문집
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• pp.211-212
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• 2000

여과집진기(fabric filter)는 높은 집진 효율로 인해 대형소각로를 포함한 환경시설의 집진 설비로 많이 적용되고 있으며, 그 중에서 pulse-jet형 여과집진기가 가장 많이 사용되는 추세이다 한편, 여과포 표면에 형성되는 dust cake의 퇴적성상(deposition morphology)은 여과집진기의 압력손실에 매우 큰 영향을 미치는데, 일정 여과속도에서 dust cake의 압력손실이 상대적으로 큰 경우에는 탈진주기가 필연적으로 짧아지는 결과를 초래한다. (중략)

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2000년도 추계학술대회 논문집
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• pp.427-428
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• 2000

공기 여과 장비에 주로 쓰이는 섬유층 여과기(fibrous filter)는 다양한 장비에 널리 쓰이고 있다. 섬유층 여과기는 이를 구성하는 섬유(fiber)의 직경, 표면 조도, 그리고 이들로 해서 나타나는 공극률, 하전여부, 등 여러 가지 필터의 특성에 따라 다양한 포집양상(Deposition Morphology)을 보인다. 제조 공정에 따라 달라지는 특성을 가진 필터는 여과 과정을 거치면서 입자가 퇴적되고 압력강하가 증가하여 필터의 수명이 다하게 된다. (중략)

• 한국광물학회지
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• 제9권2호
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• pp.64-70
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• 1996

Early weathering products of anorthosite were investigated by using scanning electron microscopy in order to trace the development of halloysite particles and aggregates. Tiny short tubes or spheres precipitate on the plagioclase surface in the initial stage of weathering and form the compact globular aggregates. With continued growth, several globules are coalesced into wrinkled halloysite aggregates, and short tubes or spheres in globules grow into long tubes forming sheaf-like aggregates. Particle shape of halloysite varies with changing supersaturation degree of weathering solution, and determines the morphology of halloysite aggregates.

• 한국표면공학회지
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• 제41권6호
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• pp.312-324
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• 2008

In this study, the functional property as a super abrasive material was secured for CBN powder by the electroless Ni-P plating on the surface of the particle. The plating solution has been prepared to control the surface morphology by regulating surfactants and process conditions. The effects of processing parameters on the surface morphology of CBN powder was discussed. The results are summarized as follows; A stable plating tendency was achieved from 1 hour after quantitatively dropping reducing agent. It was observed that more than 50% of the weight gain was obtained by Ni-P coating on the surface of CBN super abrasive powder. The morphology of the Ni-P coating layer is consisted of botryoidal and spiky type and it could be controlled by regulating processing parameters. Superior characteristic in terms of surface morphology was found in the nonionic surfactant XL-80N. It was found that XL-80N considerably decreased surface tension of CBN powder and Ni-P alloy surface then enhance wettability as well as plating rate. Metal coated CBN powder as a raw material of resin bond wheel has been developed through this investigation.

• 한국광물학회지
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• 제11권2호
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• pp.126-134
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• 1998

Surface site and areas of particles are geometrically calculated for the cubic structures to investigate how the surface sites vary with the variation of morphology and particle size. The numbers of surface site and area become smaller when the particles become equi-dimensional shape. The ratios of surface site to surface area are almost constant except the case of anion of fluorite structure. The ratios of the number of surface site to area are almost constant regardless of particle size except the size of up to 5 to 10 times of the unit cell dimension. This quantification method can be used to obtain data related to the surface reaction.