• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• 제12권9호
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• pp.791-801
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• 2000

An experimental study was conducted to analyze the effects of oil on refrigerant flow through adiabatic capillary tubes, and to develop a model for mass flow rates of refrigerant/oil mixture at various capillary tubes and flow conditions. Mass flow rates and the profiles of the pressures and temperatures along the capillary tubes was obtained with the oil concentration of R-22/SUNISO 4GS oil mixture at various test conditions. The flow trends as a function of geometry and flow conditions for pure refrigerant and refrigerant/oil mixture were similar in adiabatic capillary tubes. Mass flow rate of the refrigerant/oil mixture was less than that of pure refrigerant at the same test conditions.

• Journal of the Korean institute of surface engineering
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• 제33권2호
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• pp.69-76
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• 2000

The rf plasma chemical vapor deposition is a common method employed for diamond or amorphous carbon deposition. Diamond possesses the strongest bonding, as exemplified by a number of unique properties-extraordinary hardness, high thermal conductivity, and a high melting tempera tore. Therefore, it is very important to investigate the synthesis of semiconducting diamond and its use as semiconductor devices. An inductively coupled rf plasma CVD system for producing amorphous carbon films were developed. Uniform temperature and concentration profiles are requisites for the deposition of high quality large-area films. The system consists of rf matching network, deposition chamber, pumping lines for gas system. Gas mixtures with methane, and hydrogen have been used and Si (100) wafers used as a substrate. Amorphous carbon films were deposited with methane concentration of 1.5% at the process pressure of S torr~20 torr, and process temperature of about $750^{\circ}C$. The nucleation and growth of the amorphous carbon films have been characterized by several methods such as SEM and XRD.

• Journal of Pharmaceutical Investigation
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• 제26권2호
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• pp.125-135
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• 1996

Solid lipid nanoparticles(SLN) are particulate systems for parenteral drug administration and suitable for controlled release. SLN were prepared by homogenization process. Dispersion at increased temperature (molten lipid) was performed to yield SLN loaded with lipophilic drugs. Tetracaine base, lidocaine base, prednisolone, methyltestosterone and ethinylestradiol were used as model drugs to access the loading capacity and to study the release behavior. To investigate production parameters(lipids, surfactant concentration, homogenizing rpm) in the formation of SLN, particle size was performed by laser diffraction analysis. The mean particle size of SLN with stearic acid or trilaurin was below 1 micron. By decreasing the particle size and increasing the surfactant concentration, the release rate was increased especially in the case of highly lipophilic drug loaded SLN. Methyltestosterone or ethinylestradiol loaded SLN showed a distinctly prolonged release over a few days.

• Environmental Engineering Research
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• 제20권1호
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• pp.25-32
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• 2015

The growth of the algae strains Neochloris oleabundans, Botryococcus Braunii and Dunaliella sp. under mixotrophic conditions in the presence of different concentrations of crude glycerol was evaluated with the objective of increasing the biomass growth and algal oil content. A high biomass concentration was characteristic of these strains when grown on crude glycerol compared to autotrophic growth, and 5 g/L glycerol yielded the highest biomass concentration for these strains. Mixotrophic conditions improved both the growth of the microalgae and the accumulation of triacylglycerols (TAGs). The maximum amount of TAGs in the algal strains was obtained in the 5 g/L glycerol growth medium. The fatty acid profiles of the oil for the cultures met the necessary requirements and are promising resources for biofuel production.

• Journal of Korean Vacuum Science & Technology
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• 제3권2호
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• pp.139-144
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• 1999

Hydrogen concentration depth profiles in homoepitaxial Si(001) films grown from hyper-thermal Si beams generated by ultrahigh vacuum (UHV) ion-beam sputtering have been measured by nuclear reaction analyses as a function of film growth temperature and deposition rate. Bulk H concentrations CH in the crystalline Si layers were found tio be below detection limits, 1${\times}$1019cm-3, with no indication of significant H surface segregation at the crystalline/amorphous interface region. This is quite different than the case for growth by molecular-beam epitaxy (MBE) where strong surface segregation was observed for similar deposition conditions with average CH values of 1${\times}$1020cm-3 in the amorphous overlayer. The markedly decreased H concentrations in the present experiments are due primarily to hydrogen desorption by incident hyperthermal Si atoms. Reduced H surface coverages during growth combined with collisionally-induced filling of interisland trenches and enhanced interlayer mass transport provide an increase in critical epitaxial thicknesses by up to an order of magnitude over previous MBE results.

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권1호
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• pp.42-50
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• 2001

The activity of immobilized cell-support particle aggregates is influenced by physical and biochemical elements, mass transfer, and physiology. Accordingly, the mathematical model discussed in this study is capable of predicting the steady state and transient concentration profiles of the cell mass and substrate, plus the effects of the substrate and product inhibition in an immobilized cell-support aggregate. The overall mathematical model is comprised of material balance equations for the cell mass, major carbon source, dissolved oxygen, and non-biomass products in a bulk suspension along with a single particle model. A smaller bead size and higher substrate concentration at the surface of the particle, resulted in a higher supply of the substrate into the aggregate and consequently a higher biocatalyst activity.

• Journal of Advanced Marine Engineering and Technology
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• 제28권4호
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• pp.593-602
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• 2004

This paper is a study on the model of simultaneous heat and mass transfer process in the absorption of refrigerant vapor into a lithium bromide solution of water-cooled vertical plate absorber. The model can predict temperature and concentration profiles as well as the effect of Reynolds number on them. Also. the variations of the absorption heat and mass fluxes. and the heat and mass transfer coefficients have been investigated. The numerical result shows that the interface temperature and concentration decrease as film Reynolds number does. The absorption heat and mass fluxes, and the heat and mass transfer coefficients get their maximum values adjacent to the inlet solution. Analyses on a constant wall temperature condition have been also carried out to exam the reliability of the present numerical method by comparing to previous investigations.

• Journal of Pharmaceutical Investigation
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• 제39권5호
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• pp.373-379
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• 2009

This study was conducted to develop a pharmacokinetic-pharmacodynamic (PK/PD) model of a direct thrombin inhibitor, argatroban to predict the concentration-effect profiles in rats. Argatroban was i.v. injected to rats at 0. 2, 0.8 and 3.2 mg/kg doses (n = 4-5 per dose), and plasma drug levels were determined by a validated LC/MS/MS assay. The pharmacokinetics of argatroban was linear over the i.v. dose range studied. The thrombin time (TT) and the activated partial thromboplastin time (aPTT) were measured in rat plasma and they were found to linearly increase with increasing the dose. A 2-compartment pharmacokinetic model linked with an indirect response pharmacodynamic model was successfully utilized to evaluate the drug concentration-response relationship.

• Korean Journal of Agricultural and Forest Meteorology
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• 제1권2호
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• pp.110-118
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• 1999

This experiment was conducted to characterize the vertical transport trend of dissolved elements through throughfall, stemflow, effluent from Ao layer, and leachate out of soil profile on Pinus koraiensis stand in Experimental Forest of Kyunghee University, located in Kwangju, Kyunggi province for 12 months from July, 1998 to Jun, 1999. In addition, we investigated the content of dissolved elements and the factors influencing the water chemistry concentrations separately collected from the field. Water movement in the process of throughfall and stemflow from precipitation, and rainfall leached from Ao layer into soil water was governed by concentration of through fall, precipitation, rainfall intensity, seasonal variation, and other factors. Also, smaller changes of pH in soil water than that of dissolved elements in soil water could contribute buffer capacity, as well as balancing the concentration between cations and anions.

• Carbon letters
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• 제1권2호
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• pp.82-86
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• 2000

The present research was undertaken to evaluate the possibility of water purification filter with activated carbon fibers (ACFs) using a very low cost precursor consisting of phenolic resin coated on glass fibers. The simplified procedure involving coating, curing and activation and a very low cost glass fiber as a raw material were adopted in order to reduce manufacturing cost. The breakthrough curves of the manufactured ACFs and the commercial activated carbon (AC, Calgon F-200) were investigated in the initial concentration range from 19 to 49 ppm for benzene, toluene and ethylbenzene. From breakthrough profiles, the manufactured ACFs had significantly faster adsorption kinetics than the AC. Especially the benzene breakthrough curves, the manufactured ACF (13 g of ACF with 32% of carbon on the glass) was over the limited level (5 ppb) after flowing of 32 l at initial concentration of 15 ppm, while the commercial AC was shown about 3 ppm in initial adsorption.