• International Journal of Advanced Culture Technology
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• v.8 no.1
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• pp.226-235
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• 2020

In this paper, we present to evaluate physiological activity of Robinia pseudo-acacia leaf and its skin penetration using liposome and cell penetrating peptide. After extraction with Robinia pseudo-acacia leaf using the distilled water and supercritical, various physiological activities were examined. In antioxidants experiments, the total concentration of polyphenol compounds was determined to be 56.88 mg/g in hydrothermal extract, 45.07 mg/g in supercritical extract. The DPPH radical scavenging ability at 1,000 ㎍/mL was 33.97% in supercritical extract. The scavenging effect on SOD experiment at 500 ㎍/mL was 76.41% in supercritical extract. In the antimicrobial experiments, the hydrothermal extract had no effect, but supercritical extract represented maximum clear zone of 14.00 mm in Staphylococcus aureus strain. Liposome containing the RSE (Robinia pseudo-acacia leaf supercritical extract) reduced particle size and stabilized zeta potential. In the epidermal permeability experiment, it was confirmed that the permeation of liposome containing the RSE and cell penetrating peptides was remarkable.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.9
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• pp.913-921
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• 2009

In this study, supercritical nano plating was performed to observe its effect on materials. Using supercritical carbon dioxide as a solvent, we observed how different pressures and temperatures of the supercritical fluid affected the process and its outcome. The plating current increases as pressure increases from 8 MPa to 16 MPa, but it decreases after that. Similarly, the plating current increases as temperature is increased from $35^{\circ}C$ to $45^{\circ}C$, but the current decreases after that. Also, the thickness of the wet electrolyte plating is about $35\sim50{\mu}m$, while the thickness of the plating done using supercritical fluid is about $20\sim25{\mu}m$. At the results, It to it is considered that supercritical nano plating enable to form more thin and stable plating than wet electroplating methods. Also both of the electroplating methods could be affected plating quality by surface condition, and the supercritical nano plating has been confirmed to product more uniform plating surface than wet electroplating.

• Nuclear Engineering and Technology
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• v.52 no.7
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• pp.1409-1416
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• 2020

The study of heat transfer coefficient of supercritical water plays an important role in improving the heat transfer efficiency of the reactor. Taking the supercritical natural circulation experimental bench as the research object, the effects of power, flow, pipe diameter and mainstream temperature on the heat transfer coefficient of supercritical water were studied. At the same time, the experimental data of Chen Yuzhou's supercritical water heat transfer coefficient was collected. Through the factorial design method, the influence of different factors and their interactions on the heat transfer coefficient of supercritical water is analyzed. Through the corresponding analysis method, the influencing factors of different levels of heat transfer coefficient are analyzed. It can be found: Except for the effects of flow rate, power, power-temperature and temperature, the influence of other factors on the natural circulation heat transfer coefficient of supercritical water is negligible. When the heat transfer coefficient is low, it is mainly affected by the pipe diameter. As the heat transfer coefficient is further increased, it is mainly affected by temperature and power. When the heat transfer coefficient is at a large level, the influence of the flow rate is the largest at this time.

• Korean Chemical Engineering Research
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• v.40 no.6
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• pp.715-718
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• 2002

The supercritical dyeing process has been gaining the increasing importance because of environment reason. For further development of this process, it is needed to measure the solubility in supercritical fluids in the extensive ranges of temperature and pressure. In this study, using the semi-flow type apparatus consisted of supercritical fluid equilibrium cell, the solubility of disperse dye(C.I. disperse red 60) in supercritical HFC-134a has been measured at the temperatures of 383.2 K and 413.2 K, and in the pressure range of 50 bar to 160 bar. The solubility data are, with good agreement, correlated by an expanded liquid model which considers the supercritical fluid as compressed liquid.

• Nuclear Engineering and Technology
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• v.49 no.1
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• pp.103-112
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• 2017

Application of the supercritical condition in reactor core cooling needs to be properly justified based on the extreme level of parameters involved. Therefore, a numerical study is presented to compare the thermalhydraulic performance of supercritical and single-phase natural circulation loops under low-to-intermediate power levels. Carbon dioxide and water are selected as respective working fluids, operating under an identical set of conditions. Accordingly, a three-dimensional computational model was developed, and solved with an appropriate turbulence model and equations of state. Large asymmetry in velocity and temperature profiles was observed in a single cross section due to local buoyancy effect, which is more prominent for supercritical fluids. Mass flow rate in a supercritical loop increases with power until a maximum is reached, which subsequently corresponds to a rapid deterioration in heat transfer coefficient. That can be identified as the limit of operation for such loops to avoid a high temperature, and therefore, the use of a supercritical loop is suggested only until the appearance of such maxima. Flow-induced heat transfer deterioration can be delayed by increasing system pressure or lowering sink temperature. Bulk temperature level throughout the loop with water as working fluid is higher than supercritical carbon dioxide. This is until the heat transfer deterioration, and hence the use of a single-phase loop is prescribed beyond that limit.

• KSBB Journal
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• v.16 no.1
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• pp.95-98
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• 2001

Various factors affecting the supercritical carbon dioxide extraction of daidzein from soybean were studied. Daidzein was not extracted with pure supercritical carbon dioxide. The ethanol was an efficient modifier for supercritical carbon dioxide to extract daidzein. The extraction efficiency increased as the pressure increased up to 300 bar. At $35^{\circ}C$ and 300 bar, 93% of daidzein was extracted with supercritical carbon dioxide modified with 15% of ethanol.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.1
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• pp.1-7
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• 2017

To predict the transonic buffet onset for a supercritical airfoil with shock-boundary layer interactions, a practical steady approach has been proposed. In this study, it is assumed that the airfoil flow is steady even when buffet onset occurs. Steady Navier-Stokes computations are performed on the supercritical airfoil. Using the aerodynamic parameters calculated from Navier-Stokes solver, various steady approaches for predicting buffet onset are discussed. Among the various steady approaches considered in this study, Thomas' criterion based on Navier-Stokes computation has shown to be the most appropriate indicator of identifying the buffet onset for a supercritical airfoil with shock-boundary layer interactions. Good agreements have been obtained compared with the results of unsteady transonic wind tunnel tests. The present method is shown to be reliable and useful for transonic buffet onset for a supercritical airfoil with shock-boundary layer interactions in terms of practical engineering viewpoint.

• Journal of the Korean Ceramic Society
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• v.33 no.5
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• pp.485-494
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• 1996

Silica Aerogels with the density and porosity of 0.1g/cm3 and 96% were synthesized by two different supercri-tical drying processes (i.e additional solvent and intial pressure methods) Isoptopanol was chosen as sol-gel and supercritical drying solvents in order to synthesize aerogels at the lower temperature and pressure because the critical values of isopropanol are lower than those of methanol and ethanol commonly used. The P-V-T relationship of isopropanol was experimentally described for optimizing supercritical drying conditions such as the amount of extra solvent and supercritical drying temperature and pressure. In the addional solvent method monolithic and transparent aerogels were obtained by supercritical drying at 25$0^{\circ}C$ and 900 psing after 40% of the reactor volume was filled with isopropanol. Crack-free aerogels were synthesized at 25$0^{\circ}C$ and 1100~1200 psig by the initial pressure method with an intial nitrogen gas pressure of 400 psig and the isopropanol amount of 5% of the reactor volume.

• Textile Coloration and Finishing
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• v.15 no.2
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• pp.93-101
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• 2003

To acquire dyeing ability on aramid(Nomex) spun yarn in supercritical fluid dyeing, supercritical fluid dying(SFD) machine of 3L scale was designed. C. I. Disperse Red 60 and Red 360 were used in this work. It was possible to increase dyeing ability and to get level dyeing of fiber by attaching assistance devices(controlling device of supercritical fluid, nozzle, cover of carrier, etc.) to SFD machine. Physical properties(tensile strength, elongation, shrinkage) of Nomex spun yam treated by SFD were not changed. K/S values of dyed Nomex spun yam with Red 360 were higher than that with Red 60 and color fastness of dyed Nomex spun yam by SFD was similar to that by conventional dyeing method.

• KSBB Journal
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• v.20 no.5 s.94
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• pp.329-337
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• 2005

Because of their unique properties, supercritical fluids have been known as one of the most promising materials for the future technology. Supercritical fluid technologies have been widely applied to various operations such as extraction, impregnation, nano-particle generation, oxidation, reaction etc. Industrial applications, especially their successful usage of supercritical fluid, have been reviewed. A special case for the first successful industrial application of supercritical $CO_2$ extraction in Korea was reviewed. Its unique characteristics of enriched antioxidant, $'\grmma-tocopherol'$ enabled this industrial application in Korea in spite of its low market price. Also its size and operation conditions were known as world records.