• 한국의류산업학회지
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• 제7권3호
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• pp.333-338
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• 2005

We examined the antimicrobial effects of the cotton fabrics which were laundered at different conditions and treated with a colloidal silver solution using Staphylococcus aureus. Colloidal silver solution was made from commercial colloidal silver generator by electrolysis. The fabric which was innoculated and washed with water before drying had no more Staphylococcus aureus, but which was innoculated and dried before washing with detergent solution had lower reduction rate. The fabric washed with oxygen bleach did not have an antimicrobial effect, but rinsed with 0.07% fabric softener showed antimicrobial properties. The fabric rinsed with 0.7ppm colloidal silver solution had better antimicrobial effects. As the treating concentration of silver solution increased, the antimicrobial property of the fabric was increased. The fabric treated with 5% silver solution sustained reflectance and whiteness of untreated fabric. The colloidal silver treated fabric lost antimicrobial property after washing because nano-sized silver particles were located on uneven fiber surface without chemical bonding forces.

• Journal of Advanced Marine Engineering and Technology
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• 제29권1호
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• pp.98-106
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• 2005

The chemical conversion film formed on magnesium alloy was investigated by using the colloidal silica with some parameters such as solution pH. temperature, solution conditions, and treatment time. Moreover. the solutions consisted of colloidal silica titanium sulfate, and cobalt ions were used for the colloidal silica film to having a good corrosion resistance and adhesion properties. It was thought that the film at 298K was made with combination of Si-O. The quantity of film formed at high temperature such as 333K and 353K is smaller than dissolved quantity during chemical conversion treatment. Adding $CoSO_4$ to the colloidal silica solution enhanced the adhesion force between the silica film and magnesium substrate, The optimum conditions for the chemical conversion treatment solution were PH 2.90 s treatment, and 298K.

• 한국재료학회지
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• 제16권2호
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• pp.123-128
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• 2006

[ $BaMgAl_{10}O_{19}:Mn^{2+}$ ](BAM:Mn) phosphor particles with spherical shape were prepared by spray pyrolysis from colloidal solution with silica. The phosphor particles prepared by spray pyrolysis from aqueous solution had irregular morphology after high temperature post-treatment. On the other hand, the phosphor particles prepared from spray solution with colloidal silica had spherical shape after post-treatment. Colloidal silica used as additive improved the spherical shape and filled morphology of the precursor particles prepared by spray pyrolysis. The precursor particles with filled structure produced the BAM:Mn phosphor particles with spherical shape and non-aggregation characteristics after post-treatment at $1400^{\circ}C$ under reducing atmosphere. The phosphor particles prepared from colloidal solutions formed the crystal structure of BAM:Mn phosphor irrespective of the silica contents. The BAM:Mn phosphor particles prepared from aqueous and colloidal solutions had similar photoluminescence intensities under vacuum ultraviolet.

• Journal of Ceramic Processing Research
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• 제13권spc1호
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• pp.78-81
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• 2012

Colloidal titania nanoparticles were synthesized by a simple sol-gel process. The obtained nanoparticles showed high crystallinity and were of the anatase type. These crystalline colloidal titania nanoparticles were organically modified using methyl- and glycidyl-grafted silanes in order to enhance their stability and solution processability. The stabilized colloidal titania nanoparticles could be dispersed homogeneously without aggregation and converted into silica-titania hybrid films with the heterogeneous Si-O-Ti bonds by a low-temperature solution process. The fabricated silica-titania hybrid films showed high transparency (~ 90%) in the visible range, and low RMS roughness (<1 nm). Therefore, the organosilane-modified crystalline colloidal titania nanoparticles can be used in solution-processable functional coatings for electro-optical devices.

• Korea-Australia Rheology Journal
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• 제18권3호
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• pp.133-141
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• 2006

Carbon dioxide was absorbed into the aqueous nanometer sized colloidal silica solution of 0-31 wt% and 2-amino-2-methyl-1-propanol of $0-2kmol/m^3$ in a flat-stirred vessel with the impeller of various sizes and speeds at $25^{\circ}C$ and 0.101 MPa to measure the absorption rate of $CO_2$. The volumetric liquid-side mass transfer coefficient$(k_La)\;of\;CO_2$ was used to obtain the empirical correlation formula containing the rheological behavior of the aqueous colloidal silica solution. Reduction of the measured $k_La$ was explained by the viscoelastic properties of the aqueous colloidal silica solution. The theoretical value of the absorption rate of $CO_2$ was estimated from the model based on the film theory accompanied by chemical reaction and compared with the measured value.

• 한국의류학회지
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• 제28권9_10호
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• pp.1312-1319
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• 2004

Underwear is laundered frequently and most of them is made of cotton, but a cotton fiber is more difficult to modify than a synthetic fiber. We have attempted to determine the optimum conditions necessary whereby the lowest concentration of silver solution is needed to produce the greatest antimicrobial properties of cotton fabrics. For this study, colloidal silver was made by electrolysis. The concentration of colloidal silver was increased by increasing the area of the silver plates submerged in the water, the water temperature, the water hardness and the flow time of the water per 1l. However, the colloidal silver concentration was decreased by extending a space between the silver plates and increasing the water velocity. Cotton fabrics treated in the washing machine with 1.3 ppm colloidal silver solution for 10 minutes had effective microbial properties and an unperceivable reduction of reflectance.

• Korea-Australia Rheology Journal
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• 제16권4호
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• pp.175-182
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• 2004

Colloidal coating solution was prepared to enhance the hydrophilic property of the film surface. Water and ethanol were used as the dispersion media and (glycidoxypropyl) trimethoxysilane (GPS) as a binder in the colloidal silica coatings. Ethylene diamine was added to the colloidal silica solution as the curing agent. The colloidal silica solution was regarded as a hard-sphere suspension model with low volume fraction of the silica particles. Rheological properties of the silica suspensions modified with GPS have been investigated as a function of pH and concentration. The acidic solution showed high viscosity change by fast hydrolysis reaction and adsorption of the organic binders on the surface of silica particles. However, the hydrolysis was slow at the basic condition and the binders combined with themselves by condensation. The viscosity change was smallest at pH 7. The viscosity increased with the curing time after adding ethylenediamine, and the increase of viscosity at low pH was higher than that at high pH. The hydrophilic properties of the coating film were investigated by the contact angle of water and film surface. The smallest contact angle was shown under the strong acidic condition of pH 2.

• 한국의류학회지
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• 제29권6호
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• pp.805-813
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• 2005

In recent years, greatly increased incidences of diseases made people more concerned about their hygienic environment. Since clothes are the closest environment to man, many methods have beef proposed to impart antimicrobial properties to the textiles. Benefits associated with incorporating antimicrobial properties in textiles include protection to the wearer from microbiological attack, and prevention of odor from perspiration. Silver has been known to kill 650 different disease organisms, however, nano-sized silver particles are known as skin friendly and does not cause skin irritation. In this study, we have examined the antimicrobial effects of cotton or polyester fabric, on which nano-sized silver particles were treated. Colloidal silver solution made by electrolysis of $99.9\%$ silver stick was more effective than that by reduction of $AgNO_3.\;0.7\%$ concentration of colloidal silver solution by electrolysis is helpful to give reduction of $99.9\%$ S. aureus and K. pneumoniae on a cotton fabric without the decrease of whiteness. Since the structures of fiber and fabric effect on their antimicrobial property, PET filament fabric didn't have sufficient antimicrobial properly. The fabrics treated with up to $5\%$ colloidal silver solution didn't have the properly of antistatic and electromagnetic shield.

• 대한화학회지
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• 제43권1호
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• pp.1-7
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• 1999

이 논문에서는 광화학적 방법을 이용하여 금속 콜로이드 입자를 반도체 나노입자를 함유한 수용액내에서 제조하여 그 광학적 특성을 관찰하였다. 형성된 금속입자는 사용된 반도체 입자에 따라 다른 경향을 나타낸다. Au 금속 입자를 CdS 입자를 함유한 수용액내에서 제조한 경우 일반적인 금속 입자의 Plasmon Resonance의 특성을 보이는 반면 Ag금속 입자를 AgBr 입자를 함유한 용액내에서 제조한 경우 Red-Shift 현상을 보였고, 그 정도는 UV 조사량에 따라 달라졌다. 이러한 금속 Plasmon Resonance의 Red-Shift 현상을 Effective Medium 이론을 이용하여 이론적으로 설명하였다.

• Journal of Pharmaceutical Investigation
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• 제34권6호
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• pp.465-469
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• 2004

Colloidal gold nanoparticles might be of use as nano scale delivery systems of various therapeutic materials in the future. Recent studies have reported the feasibility of colloidal gold nanoparticles as gene delivery systems or protein delivery systems. In this study, we aimed to develop a short-step method useful for screening the optimal coating conditions of colloidal gold nanoparticles with proteins. We observed that colloidal gold nanoparticles have properties of changing its unique color when they were exposed to NaCl solution. Taking advantage of the color changing properties of colloidal gold nanoparticles, we applied the color testing method of colloidal gold nanoparticles solutions for evaluating the protein coating nature. Using bovine serum albumin as a model protein, we tested the protein coating of colloidal gold nanoparticles via the color change upon NaCl addition. The optimal coating concentration and coating conditions of colloidal gold nanoparticles with bovine serum albumin were fixed using the color testing methods. We suggest that the color testing method might be applied to optimize the coating condition of colloidal gold nanoparticles with other therapeutic proteins.