• Bulletin of the Korean Chemical Society
• /
• v.33 no.1
• /
• pp.255-260
• /
• 2012

A new series of silaanthracenophanes 2-5 composed of 1,8-diethynylanthracene unit has been synthesized from silylation reactions of 1,8-di(lithioethynyl)anthracene with 1,3-dichloro-1,1,3,3-tetraalkyldisiloxanes and 1,2-dichlorotetramethyldisilane. The silaanthracenophane products 2-4 were characterized by spectroscopic methods and X-ray crystallographic analysis.

• Journal of the Korean Applied Science and Technology
• /
• v.29 no.2
• /
• pp.238-247
• /
• 2012

Nanotechnology in the food industry is an emerging area with considerable research and potential products. Solid particles of nanoscale and microscale dimensions are becoming recognized for their potential application in the formulation of novel dispersed systems containing emulsified oil or water droplets. This review describes developments in the formation and properties of food-grade emulsion systems based on edible fat crystals, silica nanoparticles, and novel particles of biological origin nanocrystals. The special features characterizing the properties of Pickering stabilized droplets are focused in comparison with those of protein-stabilized emulsions. We also review describes application examples of these in the food industry.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.35 no.2
• /
• pp.79-89
• /
• 2009

The objective of this study was to find out the stable formulation of nano-emulsion containing high concentration of quercetin and to investigate the effect of an ethanol on the nano-emulsion prepared by POE (30) hydrogenated castor oil (HCO-30)/oil/quercetin/ethanol/water system. Nano-emulsion was prepared using emulsion inversion point (EIP) method as low-energy method plus homogenizer as high-energy method. To evaluate effect of ethanol and other components on the nano-emulsion, physical properties such as droplet size, morphology, and size distribution were determined. The optimal quercetin concentration was 0.2 % on the nano-emulsion. The droplet diameter was below 300 nm at the HCO-30 concentration below 2.00 %. Nano-emmulsion containing 4.75 % HCO-30 was the most stable and its mean droplet size was 172.40 nm. Finally, the size of nano-emulsion containing 4.00 % ethanol was 128.15 nm and size distribution was also narrow. The results showed that the breakdown process of this nano-emulsion could be attributed to Ostwald ripening. This study about effect of ethanol on the nano-emulsion showed that loading capacity of drug could be increased by using a small amount of ethanol. As prepared stable nano-emulsion, this study showed that these results could be applied to pharmaceutics, cosmetic including skin-care products, perfume and etc.

• Journal of the Korean Society for Precision Engineering
• /
• v.29 no.12
• /
• pp.1272-1278
• /
• 2012

The micro barrier rip array structures have been applied in a variety of areas including as privacy films, micro heat sinks, touch panel and optical waveguide. The increased aspect ratio (AR) of barrier rip array structures is required in order to increase the efficiency and performance of these products. There are several problems such as burr, defect of surface roughness and deformation and breakage of barrier rip structure with machining high-aspect ratio micro barrier rip array structure using orthogonal cutting method. It is essential to develop technological methods to solve these problems. The optimum machining conditions for machining micro barrier rip array structures having high-aspect ratio were determined according to lengths ($200{\mu}m$ and $600{\mu}m$) and shape angles ($2.89^{\circ}$ and $0^{\circ}$) of diamond tool, overlapped cutting depths ($5{\mu}m$ and $10{\mu}m$), feed rates (100 mm/s) and three machining processes. Based on the optimum machining conditions, micro barrier rib array structures having aspect ratio 30 was machined in this study.

• Applied Chemistry for Engineering
• /
• v.31 no.3
• /
• pp.237-257
• /
• 2020

The role of nano bio-composites precursor to chitosan are innumerable and are known for having different applications in various branches of physical sciences. The application to the sensor development is relatively new, where only few literature works are available to address the specific and critical analysis of nanocomposites in the subject area. The bio-composites are potential and having greater affinity towards the heavy metals and several micro-pollutants hence, perhaps are having wider implications in the low or even trace level detection of the pollutants. The nano-composites could show good selectivity and suitability for the detection of the pollutants as they are found in the complex matrix. However, the greater challenges are associated using the bio-composites, since the biomaterials are prone to be oxidized or reduced at an applied potential and found to be a hinderance for the detection of target pollutants. In addition, the materials could proceed with a series of electrochemical reactions, which could produce different by-products in analytical applications, resulting in several complex phenomena in electrochemical processes. Therefore, this review addresses critically various aspects of an evaluation of nano bio-composite materials in the electrochemical detection of heavy metals and micro-pollutants from aqueous solutions.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.32 no.4 s.59
• /
• pp.209-217
• /
• 2006

Emulsion is a dispersion system among liquids which are not miscible together. There are numerous cosmetic raw materials which have different physicochemical properties. Therefore, emulsion technology is very useful in cosmetics. With the development of emulsifier, several emulsification technologies have been developed. Since HLB method by Griffin in 1950's, PIT method, gel method, and D-phase methods, etc, have been developed. Recently, the application of natural emulsifier and polymeric emulsifier increases in cosmetics in order to achieve enhanced safety and biocompatibility. Besides nano-emulsion, multiple-emulsion, liquid crystal emulsion, and Pickering emulsion have been developed and applied as means of differentiating appearance and texture of products and achieving enhanced delivery of active ingredients. Meanwhile, the application studies of nano-dispersed structural system such as liposome or cubosome are on progress. Liposome is a bi- or multi-lamella layer dispersion system composed of amhiphilic molecules - phospholipids which are main components of plasma membrane. Cubosome also is a nano-sized dispersion system composed of a specific molecule like glyceryl monoloeate derived from natural products. And it has a cubic bicontinuous structure in water due to its unique molecular structure. Incorporating compounds (active materials) into such nano-particles can increase biocompatibility and delivery efficiency of target compounds. Manufacturing process and application of cosmetic emulsions and nano-particles are briefly introduced in this paper.

• Korean Journal of Materials Research
• /
• v.25 no.12
• /
• pp.659-665
• /
• 2015

The self-propagating high temperature synthesis approach was applied to synthesize amorphous boron nano-powders in argon atmospheres. For this purpose, we investigated the characteristics of a thermally induced combustion wave in the $B_2O_3+{\alpha}Mg$ system(${\alpha}=1.0-8.0$) in an argon atmospheres. In this study, the exothermic nature of the $B_2O_3-Mg$ reaction was investigated using thermodynamic calculations. Experimental study was conducted based on the calculation data and the SHS products consisting of crystalline boron and other compounds were obtained starting with a different initial molar ratio of Mg. It was found that the $B_2O_3$ and Mg reaction system produced a high combustion temperature with a rapid combustion reaction. In order to regulate the combustion reaction, NaCl, $Na_2B_4O_7$ and $H_3BO_3$ additives were investigated as diluents. In an experimental study, it was found that all diluents effectively stabilized the reaction regime. The final product of the $B_2O_3+{\alpha}Mg$ system with 0.5 mole $Na_2B_4O_7$ was identified to be amorphous boron nano-powders(< 100 nm).

• Applied Chemistry for Engineering
• /
• v.27 no.2
• /
• pp.195-198
• /
• 2016

A total four-step synthetic process of high quality optical brightening agent 4,4'-bis(2-benzoxazolyl)stilbene (BBS) from methyl 4-formylbenzoate (MFB) was developed with 73% total yield. MFB is one of the main by-products in dimethyl terephthalate (DMT) production process. Our process involves the formation of 4,4'-stilbenedicarboxylate (2) obtained from the reaction of an aldehyde in MFB with ethyl 4-((diethoxyphosphoryl)methyl)benzoate (1) and the subsequent transformation to 4,4'-stilbenedicarbonyl chloride (3). In order to prepare benzoxazole ring in BBS, various solvents and catalysts were studied. The best solvent and catalyst were found to be 1,2,4-trichlorobenzene and boric acid, respectively suitable for mass production of BBS.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.100-104
• /
• 2005

The injection molding is very effective process for various plastic products due to its high productivity. It is also good fur precise products like optical parts. Various thermoplastic materials are also available with this injection molding process. In recent, however, as the overall size of the product increases and micro or nano scale of patterns are applied to the products, we now have some problems such as low fidelity of the replication of the pattern, high molding pressure, or warpage from the in-mold stress. Injection/compression molding is studied to overcome those problems in molding large thin plate with micro pattern array on its surface. An injection compression mold is designed to 3 pieces mold for side gate. We install 4 pressure transducers and 9 thermocouples to measure the melt pressure and surface temperature in the cavity during the process. As a result, the maximum molding pressure for injection compression molding is reduced to 1/3 compared to injection molding and the uniformity of the pressure in the cavity is enhanced by about 15%.

• Journal of Life Science
• /
• v.29 no.7
• /
• pp.769-773
• /
• 2019

In this study, the migration route and the absorption rate of calcium and magnesium in apple leaves were compared and analyzed using plant nutrients prepared by wet nano-grinding technology. The plant nutrients were sprayed onto the leaves to confirm the component content and the movement route of the nanoized calcium and magnesium. At 2, 4, and 8 weeks after the plant nutrient treatment, the apple leaves were divided into petiole, lamina, and side, and SEM and EDS were used to measure the calcium and magnesium contents. The calcium and magnesium contents of the petiole increased from the 4th week after plant nutrient application to 1,115% at the 8th week. The calcium and magnesium contents of the lamina decreased after spraying but increased after 4 weeks. The calcium and magnesium contents increased in the side of the leaves compared to the control, reaching 673% after 4 weeks. The calcium and magnesium contents increased with increasing duration in all plots when compared with the control unsprayed leaves, suggesting that the usually poorly soluble calcium and magnesium were transferred from the petioles to the lamina. The results of this study indicate that improved calcium and magnesium absorption could be obtained in crops other than apples using plant nutrients produced through wet nano-processing technology. This technology is also expected to be applicable to natural products and bioindustries.