• Title, Summary, Keyword: silica gel

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Effect of Dampening Paper, Silica Gel and Temperature Treatment on Change of Flower Color of Dog-tooth Violet (Erythronium japonicum Decne) in Press Flower

  • Yoon Jae-Ho;Song Won-Seob
    • Plant Resources
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    • v.8 no.3
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    • pp.263-274
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    • 2005
  • We have studied the effects of dampening papers (Dampened paper, Newspaper, Korean paper, Flower sheet), silica gel (30g, 60g) and temperature ($20^{\circ}C,\;25^{\circ}C$) on color changes of Erythronium japonicum. In the treatment of $20^{\circ}C$, color changes were low in treatments with silica gel rather than in a treatment of dampening papers. In particular, newspaper and Korean paper showed much less changes in colors by the combination treatments with 30g of silica gel. Likewise, in the treatment of $25^{\circ}C$, color changes were low in combination treatments with silica gel rather than in a alone treatment of dampening papers. For the combination treatment with 30g of silica gel, low color changes were shown in the divisions of newspaper and Korean paper, while for the combination treatment with 60g of silica gel, low color changes were shown in the those of Korean paper and dampened paper.

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Protein-silica Interaction in Silica-based Gel Filtration Chromatography (Silica-based Gel Filtration 크로마토그래피에서의 단백질-실리카 상호작용)

  • Choi, Jung-Kap;Yoo, Gyurng-Soo
    • YAKHAK HOEJI
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    • v.35 no.6
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    • pp.461-465
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    • 1991
  • Silica-based gel filtration chromatography has been used to characterize molecular weight of proteins. However, the molecular weight measured by this method was distorted by protein-silica interactions like hydrophobic and electrostatic forces. Therefore, we characterized protein-silica interaction using two forms of phytochrome (124 kDa) having different hydrophobicity and surface charge. PH and ionic strength affected the retention time of phytochrome suggesting that electrostatic force is the major interaction between protein and silica surface.

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Syntheses of Silica Gel Bound Hemin, Biliverdin, and Bilirubin

  • Park, Yong-Tae;David A. Lightner
    • Bulletin of the Korean Chemical Society
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    • v.6 no.2
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    • pp.112-115
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    • 1985
  • 3-Aminopropylsilated silica gel bound hemin, biliverdin, and bilirubin were synthesized by reacting 3-aminopropyl silated silica gel with hemin, biliverdin and bilirubin respectively. The aspects of binding of bilirubin to amino group of 3-aminopropylsilated silica gel were studied using the above synthetic silica immobilized hemin, biliverdin and bilirubin, and oxodipyrromethene.

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Syunthesis of Silica Aerogel at Ambient Pressure and Characterization (I) (실리카에어로겔의 상압합성 및 특성연구(I))

  • 강신규;최세영
    • Journal of the Korean Ceramic Society
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    • v.33 no.12
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    • pp.1394-1402
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    • 1996
  • The Silica gel with the density of 0.2g/cm3 and porosity of 90% was synthesized. The silica wet gel was dried and heat-treated under the ambient pressure after modification of the wet gel surface by TMCS. Specific surface area total pore volume and mean pore radius of dried gel were all increased with increasing heat treatment temperature and confirmed about 1400m2/g, 4.5cc/g and 8 nm respectively after heat treatment above 25$0^{\circ}C$. But the pore size distribution of dried gel was in the range of 1-100nm and was almost indepen-dent of temperature. As the result of external shape pore characteristics and microstructure of gel using SEM similar properties were observed between the silica gel synthesized in this study and the silica aerogel through the super critical drying.

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Synthesis of Silica/Alumina Composite Membrane Using Sol-Gel and CVD Method for Hydrogen Purification at High Temperature (Sol-gel 및 CVD법을 이용한 고온 수소 분리용 silica/alumina 복합막의 합성)

  • 서봉국;이동욱;이규호
    • Membrane Journal
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    • v.11 no.3
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    • pp.124-132
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    • 2001
  • Silica membranes were prepared on a porous ${\alpha}$-alumina tube with pore size of 150nm by sol-gel and chemical vapor deposition(CVD) method for hydrogen separation at high temperatures. Silica and ${\gamma}$-lumina membranes formed by the sol-gel method possessed a large amount of mesopores of a Knudsen diffusion regime. In order to improve the $H_2$ selectivity, silica was deposited in the sol-gel derived silica/${\gamma}$-alumina layer by thermal decomposition of tetraethyl orthosilicate(TEOS) at $600^{\circ}C$. The CVD with forced cross flow through the porous wall of the support was very effective in plugging mesopores that were left unplugged in the membranes. The CVD modified silica/alumina composite membrane completely rejected nitrogen permeation and thus showed a high $H_2$ selectivity by molecular sieve effect. the permeation of hydrogen was explained by activated diffusion and the activation energy was 9.52kJ/mol.

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Properties of Nano-Hybrid Coating Films Synthesized from Colloidal Silica-Silane (콜로이달 실리카와 실란으로부터 합성된 나노하이브리드 코팅 박막의 특성)

  • Na, Moon-Kyong;Ahn, Myeong-Sang;Kang, Dong-Pil
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.232-233
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    • 2006
  • In recent years the interest in organic/inorganic hybrid materials has increased at a fast rate. Nano organic-inorganic hybrid composites have shown advantages for preparing hard coating layers. Especially, nano hybrid composite has low environmental pollution. It has high transparency, hardness, toughness, thermal dissociation temperature, hydrophobicity by using nano sized inorganic material. There are many ways in which these materials may be synthesized, a typical one being the use of silica and silanes using the sol-gel process. The structure of sol-gel silica evolves as a result of these successive hydrolysis and condensation reactions and the subsequent drying and curing. The sol-gel reactions are catalyzed by acids and produce silica sol solutions. The silica sol grows until they reach a size where a gel transition occurs and a solid-like gel is formed. Colloidal silica(CS)/silane sol solutions were synthesized in variation with parameters such as different acidity and reaction time. In order to understand their physical and chemical properties, sol-gel coating films were fabricated on glass. From all sol-gel solutions, seasoning effect of sol-gel coating layer on glass was observed.

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Synthesis of Si3N4 using Residual Organics Trapped in the Silica Gel by Sol-Gel Method (졸-겔법으로 제조된 실리카겔중의 잔류유기물을 이용한 $Si_3N_4$의 합성)

  • 김병호;신현호;이재영
    • Journal of the Korean Ceramic Society
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    • v.29 no.5
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    • pp.357-366
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    • 1992
  • Residual organics were considered as impurity in Sol-Gel method. The purpose of this study was to find the conditions to contain as much residual organics as possible in silica gel prepared from TEOS(tetraethylortho-silicate) by Sol-Gel method. Residual organics are to be expected to have reduction effect on synthesizing Si3N4 from silica gel. The results of this study are follows: 1) The maximum content of entrapped carbon was 19.8 wt.%(C/SiO2=0.25 wt.ratio) in silica gel synthesized under the conditions 1.5 fold mole water for incomplete hydrolysis, 2.5 fold mole phenol as a solvent and 0.1 fold mole HCl as a catalyst to TEOS. 2) Silica gel with organics entrapped by Sol-Gel method had a positive effect on the formation of Si3N4 compared with commercial silica gel. 3) Sintered body of synthesized $\alpha$-Si3N4 with Y2O3 and Al2O3 as additives at 175$0^{\circ}C$ in N2 atmosphere showed bending strength, 602$\pm$20 MPa and frature toughness 4.45$\pm$0.15 MPa.m1/2.

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Purifications of Phenoxyethanol Galactoside and Chlorphenesin Galactoside using Solvent Extraction followed by Gel Chromatography (Solvent Extraction과 Gel Chromatography를 이용한 Phenoxyethanol Galactoside와 Chlorphenesin Galactoside의 정제)

  • Jung, Kyung-Hwan
    • Journal of the Korean Applied Science and Technology
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    • v.34 no.4
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    • pp.954-961
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    • 2017
  • We investigated the purifications of PE-gal and CPN-gal, synthesized by transgalactosylation reaction using recombinant ${\beta}$-gal. The reaction mixture containing PE and PE-gal was first mixed with EA, and thereafter PE and PE-gal were distributed in two-phase (EA/water) system. In this system, PE and PE-gal was selectively moved into EA and water phase, respectively. Then, the water phase was collected, and silica gel chromatography was carried out using the collected water phase. Finally, we compared two purified PE-gal samples using HPLC and TLC analysis, in which the one was purified only by silica gel chromatography and the other was purified by EA extraction followed by silica gel chromatography. In the latter case, the residual PE was almost completely removed, whereas, in the former case, the residual PE was remained remarkably. Additionally, the purification yield of PE-gal was about 21% on the basis of mole. In the same purification protocol, CPN-gal was able to be purified using EA extraction followed by silica gel chromatography, in which the residual CPN was almost removed when CPN-gal was purified by EA extraction followed by silica gel chromatography.

A Study on the ZnO Supported Silica Gel (ZnO가 담지된 실리카 겔 연구)

  • Kim, S.Y.;Kim, M.Y.;Ju, C.S.
    • Journal of the Korea Society For Power System Engineering
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    • v.15 no.4
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    • pp.75-78
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    • 2011
  • There are various types of materials used in electronic industry, such as electrode material, conductor, insulator, anode, cathode and semiconductor. Electrode material type is Cu, Ti, ZnO and so on. Especially if we use mixed ZnO in soil cement or silica gel, we can have advantages in ice road to prevent freezing. We have great impact if we use supported in inorganic substances like silica gel. In this paper we have studied that ZnO supported silica gel and its properties. Zinc acetate dissolved in distilled water were loaded on the silica gel by the reaction with ammonia at $80^{\circ}C$. And we investigated particle structures of ZnO by scanning electron microscopy(SEM) and X-ray diffraction(XRD).

Adsorption of acetaldehyde at room temperature in a continuous system using silica synthesized by the sol-gel method

  • Kim, Moon Il;Kim, Suhyun;Lim, Choong-sun;Seo, Bongkuk
    • The Korean Journal of Chemical Engineering
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    • v.34 no.10
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    • pp.2773-2779
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    • 2017
  • Volatile organic compounds (VOCs) are hazardous chemicals present in outdoor and indoor air. They can be odorous and cause human health problems even at very low concentrations. Therefore, regulations on VOC gas emission are becoming stricter every year. Acetaldehyde is a VOC gas that not only has a very stinging smell but can also harm the human body by inhalation. Representative commercial adsorbents are activated carbon and silica gel. These materials feature a large surface area, which is directly related to the number of adsorption sites. In this study, a silica xerogel was synthesized by sol-gel method. The new material was tested for the adsorption of acetaldehyde in a continuous bed system, and its performance was compared to those of commercial silica gel and activated carbon. The physical properties of the samples were studied by BET analysis. Silica xerogel was characterized by XRD, FT-IR, and $^{29}Si\;MAS\;NMR$. The inlet and outlet concentrations of the VOC gas were measured from adsorption test tubes using a VOC detecting monitor. The synthesized silica xerogel presented a larger surface area and number of functional groups than the commercial silica gel, leading to improved adsorption performance and selectivity.