• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2005.11a
• /
• pp.35-36
• /
• 2005

An ejector driven by a liquid is a fluid transfer equipment to be used under a poor suction condition, which means that there exists a possibility to occur a cavitation. It is a highly reliable device because it has no movable part in it, that is only a passive equipment. The ejector is an inevitably necessary one to overcome a poor pumping condition and to mix uniformly two fluids, however it has a low efficiency since it requires a pump for its operation. This study is for the development of a new-type liquid ejector with the application of a nozzle shape alteration, which maximize the suction performance of it. which provides the increased competition with the domestic industries. Also, the increased performance opens a new manufacturing method to use a commercial pipes for the production of an ejector, which is based on a trivial loss of a performance. However, this minor loss can be sufficiently compensated by the increased performance of a new-type ejector. Therefore, the developed ejector by this study can considerably reduce the manufacturing time and cost while its performance is largely increased.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.7
• /
• pp.1505-1515
• /
• 2009

A new method to semicontinuously determine $PM_{2.5}$ ionic species with a short time resolution is described in detail. In this system, a particle collection section (mixing part, particle collection chamber, and air/liquid separator) was developed. A Y-type connector was used to mix steam and an air sample. The particle collection chamber was constructed in the form of a helix coil and was cooled by a water circulation system. Particle size growth occurred due to the high relative humidity and water absorbed particles were efficiently collected in it. Liquid samples were drained out with a short residence time (0.08-0.1 s). The air/liquid separator was also newly designed to operate efficiently when the flow rate of the air sample was 16.7 L $min^{-1}$. For better performance, the system was optimized for particle collection efficiency with various types of test aerosols such as ($NH_4)_2SO_4,\;NaCl,\;NH_4HSO_4,\;and\;NH_4NO_3$. The particle collection efficiencies were almost 100% at different concentration levels in the range over 500 nm in diameter but 50-90% in the range of 50-500 nm under the following experimental conditions: 15 coil turns, a water flow rate for steam generation of 0.65 mL $min^{-1}$, and an air sample flow rate of 16.7 L $min^{-1}$. Finally, for atmospheric applications, chemical compositions of $PM_{2.5}$ were determined with a time resolution of 20 min on January 11-24, 2006 in Seoul, Korea, and the chemical characteristics of $PM_{2.5}$ ions were investigated.

• Korean Journal of Optics and Photonics
• /
• v.28 no.5
• /
• pp.221-228
• /
• 2017

We measured the refractive index of a mixed polymer (NOA61, NOA84) in the liquid and solid states. First we made a hollow prism and filled it with UV (ultraviolet) epoxy. Measurement of the apex angle and the minimum-deviation angle gave the refractive index of the liquid polymer. To measure the refractive index of the solid polymer, an additional structure was included in the hollow prism, and the UV epoxy filling in the hollow prism was hardened. In both cases of liquid and solid polymers, the refractive index of the mixed polymer turned out to be proportional to the mix ratio. These results provide a method to vary the focal length of a double stacked cylindrical microlens array using UV epoxy.

• Journal of Environmental Science International
• /
• v.27 no.3
• /
• pp.219-225
• /
• 2018

This study was conducted to investigate the possibility of utilizing various types of nozzles and gas-liquid mixers to increase the dissolution rate of plasma gas containing ozone generated in a dielectric barrier plasma reactor. After selecting the air atomizing nozzle with the highest gas dissolution rate among the 13 types of test equipment, we investigated the influence of the operating factors on the air atomizing nozzle to determine the optimal plasma gas dissolution method. The gas dissolution rate was measured by a simple and indirect method, specifically, the measurement of KLa instead of direct measurement of ozone concentration, which requires a longer analysis time. The results showed that the KLa value of the simple mix of air and water was $0.372min^{-1}$, Which is 1.44 times higher than that ($0.258min^{-1}$) of gas emitted from a normal diffuser. Among the nozzles of the same type, the KLa value was highest for the nozzle having the smallest orifice diameter. Among the 13 types of devices tested, the nozzle with highest KLa value was the M22M nozzle, which is a gas-liquid spray nozzle. The relationship between water circulation flow rate and KLa value in the experimental range was linear. The air supply flow rate and KLa value showed a parabolic-type correlation, while the optimum air supply flow rate for the water circulation flow rate of 1.8 L / min is 1.38 times.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.31 no.9
• /
• pp.910-914
• /
• 2007

We present a simple and an inexpensive method for the fabrication of a nano-fluidic filter and a nano-pore micromixer using self-assembly of nano-spheres and surface tension. Colloid-plug was formed by surface tension of liquid in a microchannel to fabricate nanofluidic filter. When colloid is evaporated, nano-spheres in a colloid are orderly stacked by a capillary force. Orderly stacked nano-spheres form 3-D nano-mesh which can be used as a mesh structure of a fluidic filter. We used silica nano-sphere whose diameter is $567{\pm}85nm$, and silicon micro-channel of $50{\mu}m$-diameter. Fabricated nano-fluidic filter in a micro-channel has median pore diameter of 158nm which was in agreement with expected diameter of the nano-pore of $128{\pm}19nm$. A nano-pore micromixer consists of $200\;{\mu}m-wide,\;100\;{\mu}m-deep$ micro-channel and self-assembled nano-spheres. In the nano-pore micromixer, two different fluids had no sooner met together than two fluids begin to mix at wide region. From the experimental study, we completely apply self-assembly of nano-spheres to nano-fluidic devices.

• Korean Journal of Pharmacognosy
• /
• v.47 no.4
• /
• pp.366-373
• /
• 2016

Bulhwangeumjeonggisan (BHGJGS) is a traditional herbal formulation generally used in the treatment of cold and gastritis. BHGJGS consists of eight herbal plants; Atractylodis Rhizoma, Magnoliae Cortex, Citri Pericarpium, Glycyrrhizae Radix, Agastachis Herba, Pinelliae Rhizoma, Zingiberis Rhizoma and Zizyphi Fructus. Complete standardization of this formulation has not been done yet. So, a simple and accurate method was developed and validated using Ultra Performance Liquid Chromatography (UPLC) with Diode Array Detector (DAD) for the standardization of BHGJGS. UPLC conditions were optimized using a c18 RP-Amide column with mobile phase; 0.1% phosphate buffer and acetonitrile, detection wavelength; 210 and 325 nm. The linearities of calibration curves were acceptable ($R^2$>0.9994), and the limit of detection and quantification were within the ranges of 0.011-0.091 and $0.034-0.277{\mu}g/ml$ respectively. The relative standard deviation (RSD) of intra- and inter-day precisions were under 3.61%. The RSD of repeatability was under 0.68 %. The results of recovery test were 94.4-107.9%, and the RSD were under 4.6%. The developed method was used to find the contents of standard constituents in BHGJGS mix extract powder, and two commercial formulation (A and B). The data show that the developed method was specific, sensitive, accurate, and precise for analysis of BHGJGS components.

• Journal of the Korean Ceramic Society
• /
• v.46 no.2
• /
• pp.189-199
• /
• 2009

The Powder characteristics and sintering behavior of $SiO_2$ coated $BaTiO_3$ were studied. $BaTiO_3$ powders were synthesized by the liquid mix method developed by Pechini, and silica coating was prepared by alkoxide hydrolysis method with TEOS and ethanol. The particle size of the $BaTiO_3$ powders was 35 nm and the thickness of the $SiO_2$ coating layer was 5 nm. As the $SiO_2$ content increased, the $SiO_2$ layers improved the powder dispersion by increasing electrostatic repulsion between the $BaTiO_3$ particles. Effects of MgO coating on microstructure and dielectric properties of $BaTiO_3$ have been studied compared with mechanically MgO mixed $BaTiO_3$. MgO coated $BaTiO_3$ particles were prepared by a homogeneous precipitation method using $MgCl_2\cdot 6H_2O$ and urea. MgO coated $BaTiO_3$ exhibited homogeneous microstructure compared with mixed samples. XRD analysis revealed that Mg substitution for the Ti site in the MgO mixed sample was much greater than in the coated one. Electrical properties of MgO mixed and coated $BaTiO_3$ were affected by the diffusion behavior of Mg in $BaTiO_3$ lattice.

• Computers and Concrete
• /
• v.26 no.4
• /
• pp.309-316
• /
• 2020

The application of multi-variable adaptive regression spline (MARS) in predicting he long-term compressive strength of a concrete with various admixtures has been investigated in this study. The compressive strength of concrete specimens, which were made based on 24 different mix designs using various mineral and chemical admixtures in different curing ages have been obtained. First, The values of fly ash (FA), micro-silica (MS), water-reducing admixture (WRA), coarse and fine aggregates, cement, water, age of samples and compressive strength were defined as inputs to the model, and MARS analysis was used to model the compressive strength of concrete and to evaluate the most important parameters affecting the estimation of compressive strength of the concrete. Next, the proposed equation by the MARS method using particle swarm optimization (PSO) algorithm has been optimized to have more efficient equation from the economical point of view. The proposed model in this study predicted the compressive strength of the concrete with various admixtures with a correlation coefficient of R=0.958 rather than the measured compressive strengths within the laboratory. The final model reduced the production cost and provided compressive strength by reducing the WRA and increasing the FA and curing days, simultaneously. It was also found that due to the use of the liquid membrane-forming compounds (LMFC) for its lower cost than water spraying method (SWM) and also for the longer operating time of the LMFC having positive mechanical effects on the final concrete, the final product had lower cost and better mechanical properties.

• Korean Journal of Pharmacognosy
• /
• v.52 no.3
• /
• pp.192-201
• /
• 2021

Dangguisu-san (DGSS) is widely known traditional herbal medicinal formula in Korea for treatment of traumatic injury by traffic accident, ecchymosis, abdominal distension and anti-thrombosis of blood. This study was conducted to develop the simultaneous analyze method using high performance liquid chromatography (HPLC) and examine the effect of anti-inflammatory activity of DGSS-dry extract (DGSS-DE) and DGSS-mix extract powder (DGSS-MEP). Physicochemical characteristics of DGSS-DE and DGSS-MEP showed that there is no significant difference in pH, titratable acidity, total soluble solid content and browning degree except for color value (L, a, b). 15 functional constituents of DGSS were identified and the correlation coefficient values of DGSS-DE and DGSS-MEP were conformed 0.950. Also, DGSS-DE and DGSS-MEP significantly decreased the secretion of nitric oxide (NO), prostaglandin E₂ (PGE₂), interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) through inhibited expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), IL-1β, IL-6, and TNF-α. From these result, DGSS-MEP showed similar chemical composition and anti-inflammatory effect to DGSS-DE. Therefore, DGSS-DE and DGSS-MEP may be useful as potential source of drug to prevent inflammation.

• Archives of Pharmacal Research
• /
• v.18 no.6
• /
• pp.415-422
• /
• 1995

Twenty-four flavones were synthesized with various hydroxyl and/or methoxyl groups on A and B rings. Their antimutagenic properties were evaluated against ben:w(a)pyrene (BaP) and a pool of mutagenic urine concentrate (U) using a modified liquid incubation method of Ames test. The tester strain was Salmonella typhimurium TA98+S9 Mix. The antimutagenic activities were calculated by non linear regression analysis and the doses of flavones (in nmoles) required for a 50% reduction of induced revertants with BaP and U were defined as the inhibition doses (TEX>$ID_{508}{\;}and{\;}ID_{508}$ respectively). Seventeen flavones possessed significant antimutagenic activity against BaP. $ID_{508}$ ranged from 15.1 nmoles (F22) to 1000.6 nmoles (F13). Eighteen f1avones showed significant antimutagenic activity against U. $ID_{50U}$ ranged from 23.5 nmoles (F22) to 354.6 nmoles (F3). The 2',3',4'-trihydroxyflavone (F22, $ID_{508}=15.1$ nmoles, $ID_{50U}=23.5$ nmoles) and the 2',3',4',7-tetrahydroxyflavone (F20, $ID_{508}=37.8$ nmoles; $ID_{50U}=62.3$ nmoles) had antimutagenic activities similar to those of chlorophyllin ($ID_{508}=19.6$ nmoles and $ID_{50U}=44.2$ nmoles) and were evaluated against B(alP 7,8-dihydrodiol-9,10-epoxide. Against this last mutagen, the flavones which included three OH in B ring showed the highest activity and this property seemed independent of the substituent groups on A ring.