• The Korean Journal of Food And Nutrition
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• v.27 no.3
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• pp.532-537
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• 2014

Cortex Phellodendri (CP) is derived from the dried bark of Phellodendron amurense. It has been widely used as a drug in traditional Korea medicine for treating diarrhea, jaundice, swelling pains in the knees and feet, urinary tract infections, and infections of the body surface. Many analytical methods have been used to study oriental herbal medicines, such as thin-layer chromatography, column liquid chromatography, and high performance liquid chromatography (HPLC). In this study, preparative centrifugal partition chromatography (CPC) was successfully carried out in order to separate pure compounds from a CP methanol extract. The optimum two-phase CPC solvent system was composed of n-butanol: acetic acid: water (4:1:5 v/v/v). The flow rate of the mobile phase was 3 mL/min in ascending mode with rotation at 1,000 rpm. The CPC-separated fraction and purification procedures were carried out by preparatory HPLC. The $^1H$ NMR spectrum revealed that the resonances at ${\delta}$ 4.10 and 4.20 ppm corresponded to three protons ($-OCH_3$), whereas those at ${\delta}$ 6.10 ppm corresponded to two protons ($-OCH_2O-$). Further, two aromatic protons (H-11 and H-12) conveys a doublet-doublet pattern. The H-11 doublet and H-12 doublet appear at ${\delta}$ 7.98 and 8.11, respectively. The $^{13}C$ NMR. spectrum showed a tetrasubstituted with a methylenedioxy group at C2 and C3, and two methoxy groups at C9 and C10. The chemical structure of the berberine was identified by $^1H$, $^{13}C$-nuclear magnetic resonance and electrospray ionization-mass spectroscopy spectral data analysis.

• Clean Technology
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• v.18 no.2
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• pp.191-199
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• 2012

In order to reduce or remove off-flavor and volatile organic compounds (VOCs) from Laminaria japonica effectively, continuous treatment process by supercritical carbon dioxide (SC-$CO_2$) was applied. After freeze-drying, Laminaria japonica powdered with $710{\mu}m$ was used. Experiments were carried out at temperature range from 35 to $55^{\circ}C$, and pressure range from 10 to 25 MPa for evaluation of SC-$CO_2$ treatment effect. Flow rate of carbon dioxide used in this reseach was constantly fixed at 26.81 g/min. Before and after treatment of SC-$CO_2$, off-flavor and VOCs from Laminaria japonica were analyzed by gas chromatography-mass spectrometry detector (GC-MSD). Total 47 VOCs emitted from Laminaria japonica were identified before treatment of SC-$CO_2$, major components of seaweed smell (ordor) in Laminaria japonica were identified as alcohols, aldehydes, ester and acids, ketone, halogenated compounds and hydrocarbon. Off-flavor and VOCs in all experimental conditions was reduced or removed after SC-$CO_2$ treatment. Among the experimental conditions, the highest removal yield was at 25 MPa and $55^{\circ}C$.

• Fire Science and Engineering
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• v.33 no.4
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• pp.41-49
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• 2019

In the present experimental study, based on a real-scale theater, a 1/14 reduced-scale model was constructed, and the effects of natural vent and fire curtain in fire of a theater stage were investigated. The case without fire curtain under the opened natural vent showed lower temperatures in the stage, whereas the case with fire curtain under the opened natural vent showed lower temperatures in the auditorium. On the other hand, through analyzing the starting time of the temperature rise at the point near the proscenium opening in the auditorium, it was found that the opened natural vent condition can delay the starting time of smoke spread from the stage to the auditorium and suppress the temperature rise in the auditorium. Under the present experimental conditions, the fire curtain installation did not affect significantly the velocity and mass flow rate of the outflow through the natural vent of the stage, which might be due to openings in the stage. The present results can be used to examine the effects of natural vent and fire curtain in a real-scale fire of a theater and to check the accuracy of the numerical simulation code.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.12 no.1
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• pp.7-17
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• 2014

Molten salt electrorefining process achieves uranium deposits at cathode using an electrochemical processing of spent nuclear fuel. In order to recover pure uranium from cathode deposit containing about 30wt% salt, the adhered salt should be removed by cathode process (CP). The CP has been regarded as one of the bottle-neck of the pyroprocess as the large amount of uranium is treated in this step and the operation parameters are crucial to determine the final purity of the product. Currently, related research activities are mainly based on experiments consequently it is hard to observe processing variables such as temperature, pressure and salt gas behavior during the operation of the cathode process. Hence, in this study operation procedure of cathode process is numerically described by using appropriate mathematical model. The key parameters of this research are the amount of evaporation at the distillation part, diffusion coefficient of gas phase salt in cathode processor and phase change rate at condensation part. Each of these conditions were composed by Hertz-Langmuir equation, Chapman-Enskog theory, and interphase mass flow application in ANSYS-CFX. And physical properties of salt were taken from the data base in HSC Chemistry. In this study, calculation results on the salt gas behavior and optimal operating condition are discussed. The numerical analysis results could be used to closely understand the physical phenomenon during CP and for further scale up to commercial level.

• YAKHAK HOEJI
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• v.51 no.2
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• pp.133-139
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• 2007

A simple and sensitive HPLC-MS method for quantitation of 10${\alpha}$-methoxy-9,10-dihydrolysergol (MDL), the main metabolite of nicergoline, in human plasma was developed and the bioavailability parameters of MDL was assessed in Korean healthy male volunteers. Clomipramine was used as an internal standard. MDL and internal standard in plasma sample were extracted using ethyl acetate. A centrifuged upper layer was then evaporated and reconstituted with mobile phase of 10 mM ammonium acetate-acetonitrile (10 : 90, v/v). The reconstituted samples were injected into a Zorbax SB-C8 column (2.1${\times}$150 mm,5 ${\mu}$m) at a flow-rate of 0.3 ml/min. Using MS with selected ion monitoring (SIM) mode, MDL and clomipramine were detected without severe interference from human plasma matrix. MDL produced a protonated molecular ion ([M+H]$^+$) at m/z 287. Internal standard produced a protonated molecular ion ([M+H]$^+$) at m/z 315. A linear relationship for MDL was found in the range of 2.5${\sim}$100 ng/ml. The lower limit of quantitation (LLOQ) was 2.5 ng/ml with acceptable precision and accuracy. The intra- and inter-day validation for all coefficients of variation (R.S.D.%) were found less than 15%. Main pharmacokinetic parameters of 30 mg of nicergoline were revealed as follows: AUC$_t$ 321.1${\pm}$64.5 ng${\cdot}$hr/ml, C$_{max}$, 51.2${\pm}$25.3 ng/ml, T$_{max}$ 3.6${\pm}$1.5 hr, K$_{el}$ 0.12${\pm}$0.07 hr$^{-1}$ and t$_{1/2}$ 7.6${\pm}$3.4 hr. Inter subject variations and race differences were shown in comparison with the published data in the literature.

• Korean Journal of Materials Research
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• v.9 no.3
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• pp.244-250
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• 1999

MOCVD TiN films were prepared from a new TiN precursor, tetrakis(etylmethylamino)titanium (TEMAT) and ammonia. Deposition of TiN films from a single precursor, TEMA T yielded the growth rates of $70 to 1050\AA$/min, depending on the deposition temperature. Furthermore, the excellent bottom coverage of -90% over $0.35\mu\textrm{m}$ contacts was obtained at $275^{\circ}C$. The addition of ammonia to TEMA T lowered the resistivity of as- deposited TiN film to ~ $800\mu\omega-cm$ from $3500~6000\mu\omega-cm$ and improved the stability of TiN film in air. Examination of the films by Auger electron spectroscopy(AES) showed that the oxygen and carbon contents decreased with the addition of ammonia. However, increasing ammonia flow rate decreased the bottom coverage of TiN films over $0.5\mu\textrm{m}$ contacts, probably due to the high sticking coefficient of intermediate species produced from the gas phase reaction of TEMA T and ammonia. Based on the byproduct gases detected by the quadrupole mass spectrometer (QMS), the transammination reaction was proposed to be responsible for TiN deposition. In addition, XPS analysis revealed that the carbon in the films made from TEMA T and ammonia was metallic carbon, suggesting that $\beta$-hydrogen activation process occurs competitively with the transammination reaction.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.5
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• pp.61-68
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• 2020

In this study, the international standard ISO TS 16774 Part 3 Test Method for Water (wash out) Resistance and KS F 4935 ｢Sealant Injection type for water leakage maintenance of adhesive flexible rubber asphalt series｣, which are standardized as a quality control method of injection type repair materials used for water leakage cracks in underground concrete structures, are currently used in Korea. As a result, considering the performance criteria of "mass change rate -0.1%" stipulated in KS F 4935, the remaining 13 types repair materials, excluding RG-2 of synthetic rubber and UG-1 of urethane, need to be reviewed for stabilization of the loss resistance due to the flow of ground water. The results of this study are determined to be available as a basic indicator for the selection of repair materials used for cracks in concrete structures. In addition, it is expected that the results of this study can be utilized as reference data that can be reflected in the improvement of the quality of repair materials that will be researched and developed later.

• Journal of Korean Society of Forest Science
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• v.111 no.4
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• pp.490-501
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• 2022

In this study, the isoprene and terpene emissions from 32 major urban tree species were investigated. We conducted sampling using a dynamic enclosure system between June and July 2021. Seedlings aged < three years were enclosed in a chamber consisting of a 400 L transparent Tedlar bag. The air flow from the outlet of the chamber was sampled using Tenax-filled sorbent tubes under standard conditions (temperature: 30°C; PAR: 1,000 μmol/m²/sec). A thermal desorption gas chromatography/mass spectrometry system was used to analyze the following 38 biogenic volatile organic compounds: isoprene, monoterpenes, sesquiterpenes, oxygenated monoterpenes, and oxygenated sesquiterpenes. Isoprene emitters included Quercus mongolica, Salix koreensis, Robinia pseudoacacia, and Salix chaenomeloides. Monoterpene emitters included Pinus strobus, Cedrela sinensis, and Cercis chinensis. The monoterpene emission profiles were dominated by á-pinene, myrcene, camphene, and limonene. The predominant oxygenated monoterpene and oxygenated sesquiterpene were eucalyptol and caryophyllene oxide, respectively. For all species, the contributions of sesquiterpenes and oxygenated sesquiterpenes were relatively low.

• Journal of Aerospace System Engineering
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• v.18 no.1
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• pp.53-63
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• 2024

Adopting an engine igniter with high efficiency and ignition performance is essential for reliable operation of liquid rocket engines. In this study, we developed a spark torch igniter for a 450 N-scale methane-oxygen liquid rocket engine by conducting numerical analyses, igniter manufacturing and validation. Specifically, we conducted a parametric study for maximizing the enthalpy at the igniter exit, specifically by adjusting the mass flow rate, nozzle area ratio, fuel-oxidizer mixture ratio, and the igniter length-to-diameter. The heat transferred via the igniter nozzle exit was computed using 3-dimensional numerical simulations. We also manufactured and tested the igniter based on a deduced design to confirm ignition performance of the designed spark torch igniter. The igniter developed through this study could contribute to the development of practical propulsion systems such as upper-stage engines of small launch vehicles.

• Korean Journal of Agricultural Science
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• v.41 no.4
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• pp.321-326
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• 2014

The aim of this study was to investigate which hydroponic system is the optimum for growth and photosynthetic characteristics of Angelica gigas during experiment. Angelica gigas 'Manchu' were sowed and managed under a growth room chamber. The environmental conditions (temperature $22^{\circ}C/18^{\circ}C$ (day/night), relative humidity 50-70%, photosynthetic photon flux density (PPFD) $120{\pm}6{\mu}mol\;m^{-2}s^{-1}$) were maintained for 3 weeks. Forty eight seedlings with 4-5 leaves were transplanted in deep flow technique (DFT), substrate, and spray culture systems [culture bed: 800 (L) ${\times}$ 800 (W) ${\times}$ 400 mm(H)] under $150{\pm}5{\mu}mol\;m^{-2}s^{-1}$ PPFD provided with fluorescence lamps and cultivated for 11 weeks. At the end of the experiment, fresh and dry weights, leaf lenghth and width, SPAD, root fresh, and dry weights, and root volume of Anglica gigas were measured. Photosynthetic rate of Anglica gigas were measured with portable photosynthesis systems to investigate optimum PPFD, $CO_2$ concentration, and air temperature conditions. Fresh and dry weights of Anglica gigas grown in substrate were significantly greater than DFT-treated, but there were not significant with spray treatment. Leaf photosynthesis of Anglica gigas showed the tendency to sharply increase as PPFD was increased from 50 to $200{\mu}mol\;m^{-2}s^{-1}$. Though $CO_2$ saturation point was around $1000-1200{\mu}mol\;mol^{-1}$, increase in air temperature from 16 to $26^{\circ}C$ did not quite affect photosynthesis of Anglica gigas. In conclusion, Anglica gigas may be optimally cultivated with a spray culture system as air temperature, PPFD, and $CO_2$ concentration for environment are controlled at $20{\pm}3^{\circ}C$, $150{\mu}mol\;m^{-2}s^{-1}$, and around $1000{\mu}mol\;mol^{-1}$ for mass production.