• Journal of the Society of Cosmetic Scientists of Korea
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• v.22 no.2
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• pp.52-69
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• 1996

Nano-Sized TiO$_2$ particles with diameter between 2 and 5 nm are synthesized in Water/Triton X-100/n-Hexane microemulsion. Particles show the amorphous structure and partially hydroxide form. The optical absorbance of particles appears at 250nm and band edge at 340nm. Gold metal is deposited on the surface of TiO$_2$ particles by reduction reaction of Au(III) ion with sodium hypophosphite. The size of gold-deposited particles is 20nm, and the optical absorbance appears at 270nm and at 550nm. So particles show the red color. The dense precipitation is formed by aggregation in the TiO$_2$ nano-sized particles of about 5nm size. But the bulky precipitation is formed by agglomeration phenomena in the gold-deposited particles of 20nm size. And also gold-deposited particles is easily dispersed by being re-dispersed in PEG/Water solution. This study has compared those things measuring the SPF characteristics of the cosmetics made of the synthesized particles. If the particle size is controlled appropriately, then the SPF value will be higher, or more colorless cosmetics will be made.

• Macromolecular Research
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• v.16 no.4
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• pp.367-372
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• 2008

We fabricated tetra(5-n-nonyl-8-tert-butyl-2,3-pyrazino[2,3-b]indolo)porphyrazinato copper(II) (Cu-Pc-$C_8$) Langmuir-Blodgett (LB) films. We further investigated the influence of arachidic acid (AA) as a transfer promoter, as well as the effect of dipping speed, on the deposition of the films on hydrophilic and hydrophobic substrates. In the case of pure Cu-Pc-$C_8$ LB deposition on a hydrophilic substrate, the transfer ratio was close to one for up-stroke depositions, but the previously deposited film was peeled off and re-spread onto water at down-stroke depositions. Whereas the stability of the Cu-Pc-$C_8$ LB films was not improved by AA addition on hydrophilic substrates, the deposition of Cu-Pc-$C_8$ was significantly improved by the presence of AA on a hydrophobic substrate. The AA-assisted deposition had transfer ratio of close to 1 and was essentially stable up to 10-layer depositions. Comparison of the UV-visible spectrum of a Cu-Pc-$C_8$/AA LB film with that of Cu-Pc-$C_8$/AA solution in dichloroethane revealed that the Soret and Q bands for the Cu-Pc-$C_8$/AA LB film were broadened and red-shifted due to the aggregation of phthalocyanines upon assembly in the LB film.

• The Korean Journal of Food And Nutrition
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• v.32 no.4
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• pp.304-311
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• 2019

Ohmic heating is a heating method based on the principle when an electrical current passes through food. Since this method is internal, electrical current damage occurred during heating treatment. The results of ohmic heated starch's external structure, X-ray diffraction, DSC analysis and RVA were differed from those of conventional heating at the same temperature. Several starches changed more rigid by structure re-aggregation. This change in starch was caused by change of physical, chemical, rheological property. The rheology of ohmic heated potato and corn starch of different heated methods were compared with chemically modified starch. After gelatinization, sample starch suspension (2%, 3%) measured flow curves by rheometer. Cross-linked chemically modified starch's shear stress was decreased with degree of substitution reversibly. Ohmic heated more dramatic, at $60^{\circ}C$. Potato starch's shear stress was less than commercial high cross-linked modified starch. Flow curves of potato starches measured at $4^{\circ}C$, $10^{\circ}C$, $20^{\circ}C$. Showed that Ohmic heated potato starch's shear stress ranging between $4^{\circ}C$ and $20^{\circ}C$ was narrower than modified starch. According to this study, ohmic heated potato starch can be used by decreasing viscosity agent like cross-linked modified starch.

• Microbiology and Biotechnology Letters
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• v.42 no.3
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• pp.258-266
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• 2014

Sweet potato soju (SPS), a form of traditional distilled alcoholic liquor in Korea, is manufactured by the distillation of fermented broth under normal pressure, thus providing it for a uniquely smooth taste infused with the flavor of sweet potato. After distillation, the lees of SPS is produced as by-product and discarded. In this study, the ethanol and hot water extracts of lees of SPS, and their subsequent organic solvent fractions using hexane, ethylacetate (EA), butanol, and water residue were prepared in an effort at the efficient re-use of the lees of SPS. The ethanol extraction yield was 1.36-fold higher than that of the hot water extraction, and the EA fraction revealed the highest total polyphenol content among the solvent fractions. The various extracts and solvent fractions did not demonstrate hemolytic activity at up to 0.5 mg/ml concentrations against human red blood cells. In the bioactivity assay, only the EA fraction displayed a broad spectrum of anti-microbial activity against different pathogenic and food spoilage bacteria, and demonstrated significant anti-coagulation activity by inhibitions of thrombin, prothrombin and blood coagulation factors. Furthermore, only the EA fraction from the hot water extract of the lees of SPS showed anti-platelet aggregation activity, which is comparable to aspirin (a commercially available drug). Our results suggest that the EA fraction of the hot water extract prepared from the lees of SPS has a high potential as a novel resource for anti-microbial and anti-thrombosis agents.

• Industrial Engineering and Management Systems
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• v.8 no.3
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• pp.181-193
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• 2009

This paper presents a framework for controlling mobile multiple robots connected by communication networks. This framework provides novel methods to control coordinated systems using mobile agents. The combination of the mobile agent and mobile multiple robots opens a new horizon of efficient use of mobile robot resources. Instead of physical movement of multiple robots, mobile software agents can migrate from one robot to another so that they can minimize energy consumption in aggregation. The imaginary application is making "carts," such as found in large airports, intelligent. Travelers pick up carts at designated points but leave them arbitrary places. It is a considerable task to re-collect them. It is, therefore, desirable that intelligent carts (intelligent robots) draw themselves together automatically. Simple implementation may be making each cart has a designated assembly point, and when they are free, automatically return to those points. It is easy to implement, but some carts have to travel very long way back to their own assembly point, even though it is located close to some other assembly points. It consumes too much unnecessary energy so that the carts have to have expensive batteries. In order to ameliorate the situation, we employ mobile software agents to locate robots scattered in a field, e.g. an airport, and make them autonomously determine their moving behaviors by using a clustering algorithm based on the Ant Colony Optimization (ACO). ACO is the swarm intelligence-based methods, and a multi-agent system that exploit artificial stigmergy for the solution of combinatorial optimization problems. Preliminary experiments have provided a favorable result. In this paper, we focus on the implementation of the controlling mechanism of the multi-robots using the mobile agents.

• Journal of Pharmaceutical Investigation
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• v.33 no.2
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• pp.121-127
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• 2003

The objective of this study was to solidify the simvastatin self-microemulsifying drug delivery system (SMEDDS) and to improve the encapsulation efficiency of solidified alginate beads using sodium alginate. Typical simvastatin SMEDDS was composed of various oils, surfactants and cosurfactants. Also solidified-alginate beads was prepared by crosslinking liquid emulsion mixtures containing sodium alginate and other excipients (cetylpyridinum chloride (CP-Cl), hydroxypropyl methylcellulose, starch and so on). in $CaCl_2$ solution, it has been investigated that the drug release pattern and encapsulation efficiency were varied with the ratio of cationic lipid (CP-Cl). Solidified sodium alginate beads containing simvastatin SMEDDS were redispersed into media without re-aggregation. Oil droplet size of redispersed solidified-beads in media produced smaller than the initial size. The density of beads and drug loading amount were increased with increasing cationic lipid content. These systems have advantages of storage stability and predictability of drug release rate.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.6
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• pp.2815-2822
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• 2011

Clustering method in wireless sensor networks is the technique that forms the cluster to aggregate the data and transmit them at the same time that they can use the energy efficiently. In this paper, I propose the hierarchical unequal clustering method using cluster group model. This divides the entire network into two layers. The data aggregated from layer 2 consisted of cluster group is sent to layer 1, after re-aggregation the total data is sent to base station. This method decreases whole energy consumption by using cluster group model with multi-hop communication architecture. Hot spot problem can be solved by establishing unequal cluster. I also show that proposed hierarchical unequal clustering method is better than previous clustering method at the point of network energy efficiency.

• Polymer(Korea)
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• v.31 no.6
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• pp.543-549
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• 2007

We synthesized various polyurethanes(PU) haying different hard segments with different molecular weights of the soft segment to explore the effect of structure on the dispersion of silver particle in the phase of synthesized polyurethanes matrix. The thermal stability was increased by increasing the number of aromatic compound, while the degree of dispersion for silver particle was decreased. Silver particles showed better dispersion in the PU matrix having aromatic compounds when the soft segments were held constant. On the contrary, when the hard segment was held constant, silver particles on the PU matrix haying low $M_w$ of soft segment showed better dispersion than high $M_w$ of soft segment because poor chain mobility of low $M_w$ of soft segment restricted re-aggregation of silver particle. A sheet resistance of composite materials showed different aspects. In this case, the inter connection between silver particles was more important than its dispersion. In this study, the NDI-PEG 900/silver particle composite film showed the best thermal stability and electro conductivity.

• Journal of the Korea Institute of Building Construction
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• v.15 no.3
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• pp.329-337
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• 2015

Drawings in construction industry are an aggregation of knowledge containing various information generated in a number of projects. Finish details are generated by architects when they select details and methods of construction by spaces or elements. However it is so difficult to re-use details in existing drawing management systems because there are so many details in a sheet and there are several many kinds of sheets in a file. In this paper, a drawing segmentation algorithm is suggested for managing building finish details individually. Based on this algorithm, a system module for making detail blocks from files of finish details is developed. Using the drawing segmentation module, interfaces of drawing management system are suggested in the paper. Management of individual detail blocks helps to reduce of the time for searching and increases productivity of designed drawings. Also it would contribute to increase quality of designed drawings by reusing of knowledge in detail blocks.

• Journal of the Korean Society for Marine Environment & Energy
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• v.5 no.1
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• pp.3-10
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• 2002

Quantifying the settling velocities of fine-cohesive sediments is very essential in the study of ocean pollutions as well as sedimentations. Settling properties of fine-cohesive sediments are influenced largely by aggregation which occurs as a consequence of interparticle collision and cohesion of particles. Since the degree of cohesion of fine-cohesive sediments depends on physico-chemical properties such as grain size distribution, percentage of organic materials, and mineralogical compositions, and these physico-chemical properties varies regionally, the settling velocities of fine-cohesive sediments for a specific site should be determined through field or laboratory experiment. Recently, settling velocities of fine-cohesive sediments in Saemankeum coasts and Kunsan Estuary have been measured through laboratory experiments. Using these data, the previously proposed well-known settling velocity equations for fine-cohesive sediments are examined and a new equation is developed for better representation of the measured data in this study. The newly developed settling velocity equation is simpler in the form and easier in determining the related coefficients than the previous well-known equations.