• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.2
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• pp.105-109
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• 2008

In our country, limiting nutrient is known as phosphorus in the most lakes. Therefore, the removal of phosphorus is a very important process in sewage treatment. However, many of the sewage treatment plants employ the conventional activated sludge process, known to remove $10{\sim}30%$ of phosphorus. Thus, additional phosphorous removal process will be needed. Oyster shells have been known to remove phosphorus in water. The removal efficiency of phosphorus was highest at smallest size of oyster shells and at the highest pH for batch test. The phosphorous removal rate with various calcium concentrations was increased by increasing calcium concentration. At the 20 mg/l of calcium, more than 90% of phosphorous was removed in two hours. The removal efficiency of phosphorous was increased greatly at 300% of recirculation rate. With 300% of recirculation rate, the removal efficiency reached 80% at pH 11. The negative effects of bicarbonate on crystallization were observed in oyster shells. The effects of bicarbonate on rate constant were also investigated by applying these results to experimental equation. The rate constant was decreased at the inverse logarithm bicarbonate concentration.

• Polymer(Korea)
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• v.25 no.5
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• pp.699-706
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• 2001

The effects of uniaxial drawing conditions on the molecular orientation of poly (ethylene 2,6-naphthalate) (PEN) are investigated. Birefringence measurements show that the orientation is significantly enhanced at high draw ratio, low drawing temperature, and fast drawing speed. The characteristics of orientation examined by FTIR- ATR dichroism method represent almost same results. Amorphous orientation function increases with drawing rate at $120^{\circ}C$, but it decreases with drawing rate at $141^{\circ}C$. These behaviors can be explained with the relation between crystallization and chain relaxation rates. It is observed that the orientation of PEN film is accompanied by significant alignment of the naphthalene rings of PEN parallel to the film surface.

• Journal of Pharmaceutical Investigation
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• v.31 no.3
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• pp.181-184
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• 2001

The purpose of this study was to develop transdermal drug delivery system (TDDS) for the combination of physostigmine and procyclidine. The effects of various pressure sensitive adhesives (PSA) on the percutaneous absorption of procyclidine across hairless mouse skin were evaluated to select an appropriate PSA. In addition, the influences of various vehicles on the percutaneous absorption of procyclidine from PSA matrix across hairless mouse skin were evaluated using flow-through diffusion cell system at $37^{\circ}C$. Physostigmine did not have any influence on the permeation rate of procyclidine. The flux of procyclidine was the highest in silicone and PIB and was relatively lower in SIS, Acryl, and SBS adhesive matrices, however, their use was limited by the crystallization of the drug in the matrix. Among acrylic adhesives, the permeability of procyclidine was the highest from poly (ethylene oxide) grafted acrylic adhesive. Some enhancers show different enhancing effect depending on the drug, however, many of the tested enhancers showed enhancing effect for the permeation of both procyclidine and physostigmine to some extent. $Crovol^{\circledR}$ EP 40 showed the highest enhancing effect on the permeation of both compounds. The size of TDDS to provide required permeation rate was estimated to be $35\;cm^2$ based on available information.

• Polymer(Korea)
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• v.38 no.4
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• pp.477-483
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• 2014

Poly(lactic acid) (PLA) and poly(${\varepsilon}$-caprolactone) (PCL) blends with various components for melt-blown non-wovens were prepared by a twin-screw extruder. Tributyl citrate (TBC) was added in order to improve the miscibility between PLA and PCL. The results showed that small circular particles of PCL were dispersed in PLA matrix uniformly. The addition of PCL had the heterogeneous nucleation effect on the crystallization of PLA and decreased thermal stability of PLA. The flow of pure PLA and blends approached to Newtonian liquid at a low shear rate and expressed more obvious viscoelasticity at a high shear rate.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.6
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• pp.1275-1282
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• 1999

To investigate the effect of flour brew with bifidobacteria on bread characteristics, flour brew with bifidobacteria was added to baking after 16 hour incubation at 37oC. The more addition of flour brew, the higher gassing power, the better machinality of dough were obtained, resulting in the larger specific volume of bread. Flavor profile analyzed by Electronic Nose System showed that flavor components of 30% flour brew were decreased comparing with those of control and there was shown definite difference in sensory characteristics between them. Staling studies of bread containing flour brew indicated had a definite effect in retarding the staling rate of bread, with time constant calculated in 30% treatment being 3.09 days and in control being 2.08 days. The enthalphy of gelatinization was decreased from 2.51J/g to 0.61J/g with increment of flour brew, suggesting that starch crystallization is delayed. conclusion, Flour brew fermented by bifidobacteria can be used as a natural bread improver with so many benefits as better machinality, one more day storage period, slower staling rate, better bread volume and more appealing bread flavor.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.8
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• pp.692-697
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• 2016

This study investigated the effect of surface roughness of zinc oxide (ZnO) layer on the growth of polycrystalline Si layer via an Al-induced layer exchange process. It was found that the growth rate, grain size, crystallization fraction, and preferential orientation of the polycrystalline Si layer were strongly influenced by the surface roughness of the underlying ZnO layer. As the roughness of the ZnO surface increased, a higher growth rate (~40 min) and preferential Si (100) orientation were obtained because of the spatial concentration fluctuations in the Al-Si alloy, induced by the surface roughness of the underlying ZnO layer.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.342-348
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• 2001

This study was conducted to obtain granular crystalline gypsum that can be used as raw material for plaster boards or cements from waste Plaster board. We could disintegrate preferentially gypsum to gypsum needle in 10${\mu}{\textrm}{m}$ or less size among the contents of waste plaster board (gypsum, paper, fiber, and inorganic material .etc.) by hydration afterwards the dehydration of crushed waste plaster board. In this case, the optimum conditions for minimizing the size of gypsum were dehydration rate of 75%~ 85%, hydration concentration of 10~20%, agitation speed of 250~400rpm, crushing size of 2cm or less. Gypsum of 98.21% grade was recovered with 99.0% yield from under screenings of 325mesh wet screening which followed by the dehydration-hydration process performed in the conditions of dehydration rate of 80%, hydration concentration of 15%, agitation speed of 300rpm, crushing size of 2cm or less. Subsequently, Plate-like Crystalline gypsum of is 151${\mu}{\textrm}{m}$ size and the grade of 99.49% with the Yield of 98.0% from the upper screenings of 270mesh wet screening carried out after the re-crystallization of the recovered gypsum needle slurry.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1145-1150
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• 2003

Zr-based bulk metallic glasses have a significant mechanical properties such as high strength and elastic strain limit, and a good processing ability due to the deformation behavior such as superplasticity under supercooled liquid region. Recently, many researches on the determination of optimum working condition in various bulk metallic glasses have been carried out. In this study, the deformation behavior and forming conditions of $Zr_{55}Cu_{30}Al_{10}Ni_{5}$ bulk metallic glass were investigated under three different strain rates and at various temperatures between 627K and 727K. The glass transition temperature, crystallization temperature and supercooled liquid region of $Zr_{55}Cu_{30}Al_{10}Ni_{5}$ bulk metallic glass are 680K, 762K and 82K, respectively.

• Korean Journal of Food Science and Technology
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• v.21 no.6
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• pp.857-862
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• 1989

Palm oil was crystallized and melted in the differential scanning calorimeter (DSC) in the presence and the absence of sucrose fatty acid ester (SE) at the different scanning rate. In the presence of SE, the crystallization temperature of palm oil was lowered, because SE inhibited the formation of mother crystal at the initial cooling stage The melting curves of SE added palm oil changed irregularly in the ${\alpha}-form$ transition and fusion entropy. It was that the presence of SE affected the molecular diffusion in palm oil.

• Journal of the Korean Ceramic Society
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• v.26 no.4
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• pp.479-486
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• 1989

According to the phase diagram, 6Bi2O3.GeO2 composition melts congruently at 93$0^{\circ}C$ and forms a stable ${\gamma}$-6Bi2O3.GeO2 crystal phase below the melting point. But when the melt of this composition was cooled at a rate 1-15$0^{\circ}C$/min without tapping by a glass rod or impurity addition, a metastable $\delta$-6Bi2O3.GeO2 crystal phase was formed. It is due to that as the nucleation energy barrier of $\delta$-6Bi2O3.GeO2 crystals, which have more open and defective structure, is lower than that of ${\gamma}$-6Bi2O3.GeO2 crystals. When impurities or ${\gamma}$-6Bi2O3.GeO2 crystals existed in the melt, stable ${\gamma}$-6Bi2O3.GeO2 crystal phase was formed at various cooling rate. It is because of that the impurities or the ${\gamma}$-6Bi2O3.GeO2 crystals role as a seed crystal and as a result the nucleation energy barrier of ${\gamma}$-6Bi2O3.GeO2 crystals is lowered.