• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.6
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• pp.476-481
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• 2004

The aim of this study was to formulate a sustained release system for indomethacin (IND) with rosin gum obtained from a pine tree. Rosin microparticles were prepared by a disper­sion and dialysis method without the addition of surfactant. In order to investigate the influence of solvents on the formation of colloidal microparitcles, various solvents like ethanol, DMF, DMAc, and acetone were used. The rosin microparticles containing IND were characterized by X­ray differactometry (XRD) and differential scanning calorimetry (DSC). The morphologies of rosin microparticles observed by scanning electron microscopy (SEM) were spherical. The solvents used to dissolve rosin significantly affected the drug content and drug release rate of IND. The release behaviors of IND from the rosin microparticles were dependent on the drug content and size of the particles. Rosin micorparticles with a higher drug content and of a larger particle size had a slower drug release rate. Also, the IND release rate from the rosin microparticles could be regulated by the rosin content in the microparticles. From these results, rosin microparticles have the potential of being used as a sustained release system of IND.

• KSBB Journal
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• v.25 no.4
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• pp.379-386
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• 2010

In the present study, biocompatible poly (ethylene glycol) (PEG) microparticles containing coriander essential oil were prepared using a supercritical particles from gas saturated solution (PGSS) process to improve the stability of the coriander oil. The effects of various process parameters such as temperature, pressure, and nozzle diameter on the morphology and entrapment efficiency of coriander oil loaded PEG microparticles were then investigated. A positive influence on the formation of spherical microparticles was observed with increasing temperature and decreasing pressure. Furthermore, somewhat more porous microparticles were produced with an increase in pressure. At a given temperature, the highest entrapment efficiency of coriander essential oil in PEG microparticles was observed under the lowest experimental pressure condition.

• Textile Coloration and Finishing
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• v.29 no.4
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• pp.247-255
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• 2017

Scutellaria Baicalensis(SB) is widely used in traditional and modern oriental medicine. It possesses several biology activities such as anti-oxidative, anti-inflammatory, antimicrobial and antiviral activities. In this study, a functional high density polyethylene (HDPE) fabric with antimicrobial properties was developed using zeolite microparticles as a SB extract delivery carrier. Zeolites loaded with SB extract were prepared by immersing in an SB extract aqueous solution. The average size of the SB extract-loaded zeolites was about 0.1 to $2.0{\mu}m$, and the morphology of the zeolites was not altered after SB extract binding. The resulting SB extract-loaded zeolites were then immobilized homogeneously onto the HDPE fabric using acrylic binder. The encapsulation efficiency of SB extract to the zeolite was more than 45%. The in vitro release test of SB extract-loaded zeolites containing HDPE fabrics showed release of 35% of the total SB extract by day 1 in a 24hours immersion study. Moreover, the SB extract-loaded zeolites containing HDPE fabrics showed effective antimicrobial activity against Streptococcus mutans, Staphylococcus aureus, and Klebsiella pneumoniae, indicating that this innovative delivery platform potently imparted antimicrobial activity to the HDPE fabric. In conclusion, the current study suggests that the HDPE fabric containing the SB extract-loaded zeolites microparticle carrier system has potential as an effective antimicrobial textile such as safety gloves, protective gloves etc.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.341-342
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• 2008

The dynamics of nano particles in LC medium under an external electric field is of theoretical and technological interest. In this work, the dynamical characteristics of fullerene $(C_{60})$ particles in liquid crystal (LC) medium under dc electric field have been investigated. This effect was studied for homogeneously aligned nematic LC cells driven by in-plane field. The $C_{60}$ was found to be aggregated in a form of cluster inside the LC medium. Hence polystytene was used to protect the aggregation of $C_{60}$ in LC medium. When the electric field was applied, the fullerenes start to move in direction of applied electric field. The density of $C_{60}$'s particles at the electrodes increase with increase in the value of applied electric field. The dynamical motions of fullerene $(C_{60})$ particles in liquid crystal (LC) suggest that fullerene can be designed for electrophoretic displays (i.e., electronic ink).

• Clean Technology
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• v.13 no.4
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• pp.237-243
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• 2007

Phase behavior of the ternary systems of water-insoluble simvastatin drug, which is well known to be effective drugs for hypercholesterolemia therapy, in solvent mixtures of dimethyl ether (DME) and supercritical carbon dioxide was investigated to present a guideline of establishing operating conditions in the particle formation of the drugs by a supercritical anti-solvent recrystallization process utilizing DME as a solvent and carbon dioxide as an anti-solvent. The solubilities of simvastatin in the mixtures of DME and carbon dioxide were determined as functions of temperature, pressure and solvent composition by measuring the cloud points of the ternary mixtures at various conditions using a high-pressure phase equilibrium apparatus equipped with a variable-volume view cell. The solubility of the drug increased as the DME composition in solution and the system pressure increases at a fixed temperature. A lower solubility of the drug was obtained at a higher temperature.

• Journal of the Korean Society of Clothing and Textiles
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• v.9 no.2
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• pp.75-84
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• 1985

In order to improve dyeing and finishing technology of thin cloth of microfiber(super-fine fiber), the degrees of deep dyeing method, the light fastness, and the washing fastness were investiagted. 1. The thin cloth made of microfiber, $0.15^d\~0.2^d$, was conjugated type and the dyeing degree was lower at 5 to $10\%$ than that of cloth made of common fiber. The cloth of excellent dyeing fastness, light fastness, was developed by increasing the concentration of dye of high quality up to $5\~10\%$. 2. Because refractory rate of microfiber of $0.2^d$ was lower than that of $0.01^d$, the surface refractory rate of $0.2^d$ was lower than that of $0.01^d$ fiber. Therefore the surface of micro-fiber, $0.2^d$, was more rougher than that of $0.01^d$ and it belongs to separate type. 3. The higher degree of dyeing was increased by using dye of microparticle. Also the degree of textile printing was increased by adding urea solution ($20\%$) and glycerine diethylene glycol. 4. Light fastness was very excellent, marked 5 grade. However, washing fastness was 2$\~$3 grade. After dyeing, we could improve to 4 grade, through hot water washing including some organic chlorine solvent. 5. Super microfiber of $0.01^d$ will not be dyed by present dye and dyeing equipment, because right reflection light rate(white light) of fiber surface was too high and the more refraction rate higher the more surface refraction rate will be increased.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.5
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• pp.523-529
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• 2010

Recently, several research groups have been investigating the motion of flagellated bacteria, with the aim of examining the feasibility of using bacterial chemotaxis as an efficient power source for microactuators. In this study, microparticle-tracking velocimetry ($\mu$-PTV) is used for investigating the motion of fluorescent microbeads propelled by bacterial chemotaxis. Flagellated bacteria, Serratia marcescens, are spontaneously attached to the surface of the fluorescent polystyrene (PS) microbeads in an aqueous culture. The microbeads thus treated are injected into the test medium, which contains the solidified chemoattractant L-aspartate. With time, the particles slowly move toward the zone in which the L-aspartate concentration is high. This study shows that chemotaxis of flagellated bacteria can be applied as an efficient power source for microactuators.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.5
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• pp.1-10
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• 2008

Synthetic mineral microparticles (SMM) is a patented system which has been developed to promote drainage of water and retention of fine particles during papermaking. It is shown in patents that the SMM system can have advantages in both of drainage and retention, compared with montmorillonite (bentonite), which is one of the most popular materials presently used in this kind of application. Turbidity and gravity drainage time were measured using a Britt-Jar test with representative SMM formulations, in order to confirm the efficacy of SMM covering a wide range of compositions and discover effects of some key variables that have the potential to lead to unexpected advantages in terms of the effectiveness of the microparticles, when used in combination with a cationic polyacrylamide treatment of papermaking furnish. An iron silicate showed highest retention performance, as well as suitably fast drainage time relative to other metal silicate and bentonite. Zinc silicate improved retention and drainage. SMM synthesized from aluminum sulfate ($Al_2(SO_4){_3}$) did not show a benefit in retention and drainage, relative to bentonite. SMM synthesized from aluminum chloride ($AlCl_3$) performed better in drainage and retention than bentonite when the Al/Si ratios were 0.76 and 1.00. It was found that when the Al/Si ratio and neutralization are considered, pH variation due to the change of Al/Si ratio can be a key factor to control the size of primary metal silicate particles and the degree of coagulation of the primary particles.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2008.05a
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• pp.1-46
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• 2008

The ability to control filler performance and fines retention is vital in the development of both filled and non filled grades, respectively. This is very important when achieving the desired sheet structure necessary to maximize machine performance and end user demands. A narrow balance exists in attaining the desired retention and formation particularly in systems with heavier ash loads and producing paper and paper board on higher speed high shear equipment. A new generation of both cationic and anionic micropolymer technologies has been developed. These water based chemistries are volatile organic compound (VOC) and alkyphenol ethoxylate (APE) free. When these novel micropolymers are applied with linear poly-acrylamide or in conjunction with inorganic microparticle technologies (such as silica or swellable minerals), substantial increases in drainage, fibre retention and ash retention are observed. These improvements have been observed not only in high filled wood and non wood containing grades such as fine paper and super calendared sheets (SCA), but also in low filled newsprint grades. Of particular note is the drainage improvement seen with the application of the cationic micropolymers in unbleached packaging grades with poly-acrylamide.

• Journal of Biosystems Engineering
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• v.37 no.2
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• pp.113-121
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• 2012

Purpose: Particle separation in solution is one of important process in a unit operation as well as in an extract preparation for biosensors. Contrary to centrifuge-type of mesh-type filter, using an ultrasonic standing wave make the filtering process continuous and free from maintenance. It is needed to investigate the characteristics of particle movement in the ultrasonic standing wave field. Methods: Through the computer simulation the effects of major design and driving parameters on the alignment characteristics of particles were investigated, and a cylindrical chamber with up-stream flow type was devised using two circular-shape PZTs on both sides of the chamber, one for transmitting ultrasonic wave and the other for just reflecting it. Then, the system performance was experimentally investigated as well. Results: The speed of a particle to reach pressure-node plane increased as the acoustic pressure and size of particle increased. The maximum allowable up-stream flow rate could be calculated as well. As expected, exact numbers of pressure-node planes were well formed at specific locations according to the wavelength of ultrasonic wave. As the driving frequency of PZT got close to its resonance frequency, the bands of particles were observed clearer, which meant the particles were trapped into narrower space. Higher excitation voltages to the PZT produced a greater acoustic force with which to trap particles in the pressure-node planes, so that the particles gathered could move upwards without disturbing their alignments even at a higher inlet flow rate. Conclusions: This research showed the feasibility of particle separation in solution in the continuous way by an ultrasonic standing wave. Further study is needed to develop a device to collect or harvest those separated particles.