• 산업기술연구
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• 제23권A호
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• pp.199-206
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• 2003

The charcoal-encapsulated methyl silica microcapsules were prepared by a O/W microemulsion sol-gel method, and the adsorption properties on aquatic humic acid were investigated. The capsules prepared were spherical, $100{\sim}1000{\mu}m$ in size. The size distribution was controllable by adjusting the size of charcoal powder, charcoal/methyl silica ratio, and agitating speed in O/W sol-gel process. Adsorption efficiency of charcoal for aquatic humic acid was decreased after encapsulation by methyl silica shell. The decreased adsorption efficiency can be dependent on the decrease of the BET surface area and pore volume after encapsulation. Diffusion properties of humic acid through the capsule shell also played an important role on adsorption efficiency. Therefore, the reasonable target pollutants for the capsules can be VOC or odor molecules which can overcome diffusion barrier through shell of capsules in air condition. Functionalization methods for the charcoal-encapsulated $CH_3(SiO)_n$ microcapsules by incorporation of $TiO_3$ as a phtocatalytic function and by incorporation of inorganic pigment as a color function were also investigated. $TiO_2$ coating properties were controllable by adjusting pH, temperature, and the concentration of $TiOSO_4$. In XRD measurement, the crystal form of the coated $TiO_2$ was anatase. For the colorization of the capsules, inorganic pigments were more efficient than organic dyes, and various color was introduced to the capsules using inorganic pigments.

• 자연과학논문집
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• 제9권1호
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• pp.9-17
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• 1997

염색가공 폐액중의 반응성 염료에 대한 탈색효과를 검토하기 위하여 산화력이 강한 오존을 사용하여 염료의 농도, 처리용액의 pH, 처리용액의 온도조건 등을 변화시켜 가며 오존의 농도와 피로시간에 대한 염료의 탈색과정에 대하여 연구하였다. 오존의 처리 능력은 염료 폐액의 농도가 높아지면 그만큼 오존이 많이 필요하게 되므로 처리 속도도 떨어졌다. 반응성 염료의 탈색 속도는 진한 색상인 blue가 제일 늦었으며 옅은 색상일수록 빠르게 탈색이 진행되었다. 오존의 처리 시간이 경과함에 따라 반응성 염료의 색상은 중간색을 거쳐 무색으로 변하여 색상이 파괴됨을 보였다. 반응성 염료는 색상에 따라 약간의 차이는 있지만 알칼리 영역에서보다는 산성영역에서 더 빠르게 탈색이 진행되었다. 오존처리 온도가 낮을수록 탈색속도가 빠르게 나타났지만 그 차이는 적었다.

• 대한화학회지
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• 제65권2호
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• pp.125-132
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• 2021

An electrochromic nickel oxide thin film was fabricated on a flexible PET/ITO substrate using a nanocrystallite- dispersed coating sol and bar coater. Nanocrystalline NiOx of 3-4 nm crystallite size was first synthesized by base precipitation and thermal conversion. This NiOx nanocrystallite powder was mechanically dispersed in an alcoholic solvent mixed with a silane binder to prepare a coating sol for thin film. This sol method is different from the normal sol-gel method in that it does not require the conversion of precursor by heat treatment. Therefore, this method provides a very facile method to prepare NiOx thin films on any kind of substrate and it can be easily applied to mass production. The electrochromic performance of this NiOx thin film on PET/ITO electrode with a thickness of about 400 nm was investigated in a nonaqueous LiClO4 electrolyte solution by cyclic voltammetric and repeated chronoamperometric measurements in conjunction with spectrophotometry. The visible light modulation of 44% and the colorization efficiency of 41 ㎠/C at 550 nm were obtained at the step potentials of -0.8/+1.2 V vs Ag and a duration of 30 s.

• 대한화학회지
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• 제67권1호
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• pp.33-41
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• 2023

Nanocrystallne WO₃ and MoO₃ with several different sizes and crystal structures were prepared by simple acid precipitation and subsequent heat treatment. The photochromic (PC) properties of these samples were comparatively investigated in powder state by monitoring diffuse reflectance spectral changes after bandgap irradiation. The PC effect of hexagonal WO₃ and monoclinic WO₃ strongly depended upon crystallite size rather than crystal structure. The smaller the crystallite size, the better the PC effect. However, orthorhombic WO·H₂O and MoO₃ having hexagonal and orthorhombic structures did not follow this trend. One consistent result for all WO₃ and MoO₃ samples is that the heat treatment in air, which changes crystallinity, whether it changes the crystal structure or only the crystallite size, reduces the PC effect. Since the thermal treatment reduces the surface oxygen defect sites, we believe that the PC effect of WO₃ and MoO₃ depends critically on the surface oxygen defect sites that serve as deep trap sites for photogenerated electrons and oxygen radical holes. We also found that the proton insertion claimed by double charge injection model is not critical for the PC effect.

• 농약과학회지
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• 제4권1호
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• pp.11-18
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• 2000

본 연구에서는 세포막파괴형 제초활성물질을 보다 효율적으로 검정할 수 있는 방법을 확립하고자 시험하였으며 검정전략으로서는 막과산화에 의해 풍부히 형성되는 카보닐 및 알데히드류 화합물을 MBTH/ferric chloride로 발색시켜 96-well 상태에서 검정하는 방법을 적용하였다. 검정과정상에 필요한 제반조건(식물재료, 광도, 광조사 시간, 발색을 위한 시약의 적정농도 및 반응시간 등)들을 최적화시킨 후 여러 가지 작용기작을 가지는 기존제초제들의 오이자엽 절편에 대한 반응을 조사하였다. 그 결과, PROTOX 저해제와 paraquat와 같이 신속히 세포막 파괴를 일으키는 기작을 가진 제초제에 양호한 반응을 보였다. 실제 온실에서의 제초활성이 각기 다르게 나타난 7가지 신규화합물을 대상으로, 온실에서의 제초활성과 본 검정법에서의 활성을 비교했을 때 매우 높은 상관성을 나타내었다. 본 검정법은 60 ${\mu}L$의 시험용액에 직경 4 mm의 오이자엽 절편 한 개만을 이용하므로 96-well microtitre plate에서 미량의 화합물을 동시에 대량으로 검정할 수 있다는 장점을 가지고 있으나, 발색을 위해 용액을 끓이는 과정이 필요하기 때문에 효율성을 제고하는데 한계성을 가졌다.