• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.3
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• pp.221-226
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• 2014

IIn this study, O/W type nano-emulsions were prepared by phospholipid-nonionic surfactant mixtures and octyldodecylmyristate using the phase transition low-energy emulsification method. The nano-emulsions were formed only in the very narrow area of the concentration of mixed surfactant and oil molar ratio of around 1 : 1. The particle size of the emulsions was decreased as adding the aqueous phase into the emulsions after phase inversion point unlike the emulsions formed only with nonionic surfactant. Nano-emulsion was stable at room temperature for more than a month. Thus, the nano-emulsions containing phospholipids can be widely used as a cosmetic formulations.

• Journal of Microbiology and Biotechnology
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• v.15 no.1
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• pp.55-58
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• 2005

Sophorolipid was produced by Candida bombicola ATCC 22214 from soybean dark oil, a byproduct of soybean oil processing. With a fed-batch culture of C. bombicola for 7 days, 90 g/l of sophorolipid was obtained. The CMC (critical micelle concentration) and minimum surface tension of the sophorolipid in aqueous solution were found to be 150 mg/l and 48 mN/m, respectively. The dispersion capability of sophorolipid was higher than that of the chemical surfactants such as SDS and Brij30. The molar solubility ratio (MSR) of 4-methylnaphthalene was 0.2. Linoleic and oleic acids were the main constituents of the fatty acid composition of the sophorolipid. The sophorolipid showed antimicrobial activity against Propionibacterium acne and Bacillus subtilis.

• Elastomers and Composites
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• v.52 no.2
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• pp.99-104
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• 2017

Due to the depletion of fossil oil and the increasing oil price, bio-plastic is currently topical. Bio-based plastics are synthesized from plant resources, unlike conventional petroleum-based counterparts. Therefore, the former minimizes global warming and reduces carbon dioxide emission. Fossil polycarbonate (PC)has good mechanical and optical properties, but its synthesis requires bisphenol-A and phosgene gas, which are toxic to humans. To address these problems, the fused deposition 3D printing process (hereafter, FDM) is studied using environmentally-friendly and high-strength bio-based PC. A comparisonof the environmental impact and tensile strength of fossil PC versus bio-based PC is presented herein, demonstrating that bio-based PC is more environmentally-friendly with higher tensile strength than fossil PC. The advantages of bio-based PC are applied in the FDM process for the fabrication of environmentally-friendly baby toys.

• Applied Chemistry for Engineering
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• v.24 no.3
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• pp.260-265
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• 2013

In this study, nano-emulsions containing 0.01, 0.03, 0.05, and 0.10% ethyl acetate fraction of Hippophae rhamnoides (H. rhamnoides) leaf extracts were prepared. The particle size, particle size distribution and skin permeability of the nano-emulsions were evaluated for five weeks. Nano-emulsion was prepared by the sequential use of homogenizer and microfluidizer. Nano-emulsion containing the ethyl acetate fraction exhibited a monodispersed form. Nano-emulsion containing 0.03% ethyl acetate fraction was the most stable for five weeks. The in vitro skin permeation study of nano-emulsion containing 0.03% ethyl acetate fraction was carried out using Franz diffusion cell. The nano-emulsion showed a better skin permeability than that of O/W emulsion. These results indicate that the nano-emulsion containing the ethyl acetate fraction of H. rhamnoides leaf extract showed a remarkable stability and skin permeability than that of O/W emulsion.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.36 no.1
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• pp.1-16
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• 2010

The preparation and properties of emulsions stabilized by the adsorption of solid particles at the oil-water interface are reviewed. Comparison is made with the behaviour of surfactant-stabilized emulsions. Many of the properties of Pickering emulsions are attributed to the large free energy of adsorption for particles. The main differences is due to the irreversible adsorption of particles to the interface. Phase inversion from w/o (water-in-oil) to o/w (oil-in-water) can be brought by increasing the volume fraction of water. Hydrophilic particles tend to form o/w emulsion whereas hydrophobic particles form w/o emulsion. The contact angle at the oil-water interface is main parameter to decide the emulsion type. The aspects of stability of Pickering emulsions are in contrast to general emulsions in some points. The possibility using Pickering emulsions for cosmetics is also proposed.

• Applied Chemistry for Engineering
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• v.24 no.3
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• pp.231-238
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• 2013

In this study, the $TiO_2$ nano spheres were synthesized by Sol-gel method to give an excellent UV-blocking effect and increase waste adsorption. The pH value was adjusted to obtain a superb UV-blocking effect and adsorption capacity due to the high surface area which is the characteristics of porosity. Base treated $TiO_2$ showed outstanding characteristics. The adsorption of gycerine onto the $TiO_2$ sample using TGA resulted in a high surface area of 1.16 mg/mg. This also showed a high reflectance in the UV-A region. In order to find the optimum dispersion, inorganic powder particles were maintained their sizes as 180 nm for about 6 months. The size of particles were measured using ester oil and silicon oil. Overall, the results reveal that $TiO_2$ has an excellent capability sunscreen in the UV-A region and skin waste adsorption.

• Nano
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• v.13 no.12
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• pp.1850141.1-1850141.11
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• 2018

Sodium ion batteries based on the more sodium source reserve than that of lithium have been designed as promising alternatives to lithium ion batteries. However, several problems including unsatisfied specific capacity and serious cyclic stability must be solved before the reality. One of the effective approaches to solve the abovementioned problems is to search for suitable anode materials. In this work, we designed and prepared $FeSe_2$ nanoflakes via a simple hydrothermal method which can be adjusted in composition by Fe precursor. As a potential anode for sodium storage, the optimized $FeSe_2$ electrode was further evaluated in different electrolytes of $NaClO_4$ in propylene carbonate/fluoroethylene carbonate and $NaCF_3SO_3$ in diethylene glycol dimethyl ether. The capacity was about $470mAh\;g^{-1}$ and $535mAh\;g^{-1}$ at $0.5A\;g^{-1}$, respectively, in the voltage between 0.5 V and 2.9 V in the cycle of stabilization phase. Superior performance both in capacity and in stability was obtained in ether-based electrolyte, which affords the property without plugging the intermediates of transition metal dichalcogenides during charge/discharge processes.

• Journal of Ocean Engineering and Technology
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• v.23 no.6
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• pp.99-104
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• 2009

PTFE has good mechanical and chemical stability at a wide range of temperatures and demonstrates a low friction coefficient value. PTFE is being used for self-lubricating parts in industry. But it shows a high wear rate. Thus, PTFE and nano-diamond powder were mixed into a composite and the wear properties of a PTFE coating layer on Al6061 was investigated. A ball-on-disk type of wear tester was used under a dry condition and different temperatures of oil. After the wear test, the wear track wasexamined by optical microscope. The PTFE-diamond showed the lowest friction coefficient (0.02) of all the lubricants in the experiments. The friction coefficient was shown to be directly related to the diamond powder in the PTFE coating. Adhesion estimations were performed by a scratch test, which is mainly used for coatings. The critical load between the coating and substrate was defined through analyses of the friction load, normal load curve, and acoustic emissions, along with optical microscope observations. The scratch test results showed that an import item (SWISS) gave the highest critical load values.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1039-1044
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• 2014

Many research works have been conducted to improve a lubrication performance on diesel engines working in severe conditions. In this study the lubricant containing diamond nano-powder is applied on a diesel engine, and the engine performance is analyzed. The concentration of nano-diamond lubricant fabricated by the matrix synthesis dispersion method is varied. The test results with the nano lubricants are compared with the base oil. The result shows the improvement of efficiency with friction reduction and exhaust emissions reduction of CO, smoke and so on.

• Polymer(Korea)
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• v.37 no.6
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• pp.702-710
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• 2013

Zaltoprofen loaded polyoxalate (POX) microspheres were prepared by an emulsion solvent-evaporation/extraction method like oil-in-water (O/W) for sustained release of zaltoprofen. The influence of several preparation parameters such as fabrication temperature, stirring speed, intensity of the sonication, initial drug ratio, molecular weight ($M_w$) of POX, concentration of POX and concentration of emulsifier has been investigated on the zaltoprofen release profiles. Physicochemical properties and morphology of zaltoprofen loaded POX microspheres were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimeter (DSC) and Fourier transform infrared (FTIR). Through the analyzed results, it was demonstrated that the characteristics of the microspheres greatly affected by the prepared condition. The releases behavior of zaltoprofen was investigated for 10 days in vitro. It was confirmed that the release behavior of zaltoprofen can be controlled by the manufacturing factor of solvent-evaporation/extraction method.