• Journal of Korean Society of Water and Wastewater
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• v.29 no.1
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• pp.77-88
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• 2015

Soil column experiments were evaluated effects of silver nanoparticles (i.e., 0, 2.5, 5, and 10 mg/L) on the microbial viability which is strongly associated with the degradation of organic matter, pharmaceutically active compounds(PhACs) and biological oxidation of nitrogenous compounds during river bank filtration. The addition of silver nanoparticles resulted in almost no change in the aqueous matrix. However, the intact cell concentration decreased with addition of silver nanoparticles from 2.5 to 10 mg/L, which accounted for 76% to 82% reduction compared to that of control (silver nanoparticles free surface water). The decrease in adenosine triphosphate was more pronounced; thus, the number and active cells in aqueous phase were concurrently decreased with added silver nanoparticles. Based on the florescence excitation-emission matrix and liquid chromatograph - organic carbon detection analyses, it shows that the removal of protein-like substances was relatively higher than that of humic-like substances, and polysaccharide was substantially reduced. But the extent of those substances removed during soil passage was decreased with the increasing concentration of silver nanoparticles. The attenuation of ionic PhACs ranged from 55% to 80%, depending on the concentration of silver nanoparticles. The attenuation of neutral PhACs ranged between 72% and 77%, which was relatively lower than that observed for the ionic PhACs. The microbial viability was affected by silver nanoparticles, which also resulted in inhibition of nitrifiers.

• Applied Chemistry for Engineering
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• v.8 no.2
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• pp.286-291
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• 1997

Taxol which is recognized as a powerful anticancer reagent was extracted from yew extract and separated by NP-HPLC (Normal-PhaseHigh Performance Liquid Chromatography). The experiments were performed in the isocratic mode with $5{\mu}l$ to $100{\mu}l$ injection volume and 1ml/min mobile phase flow rate. The major mobile phase was hexane and small amounts of ethanol, methanol, 1-propanol and isopropanol were added to change the retention behavior. Prior to a real sample, the artificial mixture of taxol, cephalomannine and 10-deacetyltaxol was tested. They are hard to be separated because of similar chemical structures. The experimental results showed that the proper composition of mobile phase for separating the three components was found 96% hexane and 4% ethanol(vol.%) or 96% hexane, 2% 1-propanol and 2% methanol(vol.%). Compared to the run time of 80 minutes for the binary system, the mixture was separated within 50 minutes with the less amount of mobile phase for the ternary system. Finally, $1{\mu}g$ of taxol was separated from yew tree extracts under the optimum operating conditions.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.4
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• pp.459-469
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• 2016

Gas hydrate desalination process is based on a liquid to solid (Gas Hydrate, GH) phase change followed by a physical process to separate the GH from the remaining salty water. The GH based desalination process show 60.5-90% of salt rejection, post treatment like reverse osmosis (RO) process is needed to finally meet the product water quality. In this study, the energy consumption of the GH and RO hybrid system was investigated. The energy consumption of the GH process is based on the cooling and heating of seawater and the heat of GH formation reaction while RO energy consumption is calculated using the product of pressure and flow rate of high pressure pumps used in the process. The relation between minimum energy consumption of RO process and RO recovery depending on GH salt rejection, and (2) energy consumption of electric based GH process can be calculated from the simulation. As a result, energy consumption of GH-RO hybrid system and conventional seawater RO process (with/without enregy recovery device) is compared. Since the energy consumption of GH process is too high, other solution used seawater heat and heat exchanger instead of electric energy is suggested.

• Structural Engineering and Mechanics
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• v.75 no.5
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• pp.571-583
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• 2020

Permeation grouting is of great significance for consolidating geo-materials without disturbing the original geo-structure. To dip into the filtration-induced pressure increment that dominates the grout penetration in permeation grouting, nonlinear filtration coefficients embedded in a convection-filtration model were proposed, in which the volume of cement particles in grout and the deposited particles of skeleton were considered. An experiment was designed to determine the filtration coefficients and verify the model. The filtration coefficients deduced from experimental data were used in simulation, and the modelling results matched well with the experimental ones. The pressure drop revealed in experiments and captured in modelling demonstrated that the surge of inflow pressure lagged behind the stoppage of flow channels. In addition, both the consideration of the particles loss in liquid grout and the number of filtrated particles on pore walls presented an ideal trend in filtration rate, in which the filtration rate first rose rapidly and then reached to a steady plateau. Finally, this observed pressure drop was extended to the grouting design which alters the water to cement (W/C) ratio so as to alleviate the filtration effect. This study offers a novel insight into the filtration behaviour and has a practical meaning to extend penetration distance.

• Journal of Mushroom
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• v.11 no.2
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• pp.107-110
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• 2013

This study was carried out to optimize the conditions for a chemotaxonomic classification of Ganoderma species. The mycelia of Ganoderma species were extracted with 100% MeOH, and the concentrated extracts were further purified and partitioned with column chromatography (HP20) and n-BuOH, respectively. From the result of high-performance liquid chromatography (HPLC), the constituents of the samples were efficiently separated with a Chemco Pak $C_{18}$ column ($250mm{\times}4.6mm$) by linear gradient elution using water and acetonitrile as mobile phase components at a flow rate of 0.8 ml/min and detector wavelength at 210 nm. However, the samples without purification or partition were not detected the characteristic peaks. This profile could be used to classify and identify the various Ganoderma species.

• Korean Journal of Medicinal Crop Science
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• v.22 no.2
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• pp.147-153
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• 2014

The Ponciri fructus immaturus (Poncirus trifoliata Rafinesque) has been used in oriental medicine for uterine contraction, stomachache, abdominal distension and cardiovascular diseases. Two main compounds, poncirin and naringin were successfully analyzed by high performance liquid chromatography (HPLC) and carried out method validation according to ICH guideline. A successful resolution and retention times were obtained with a $C_{18}$ reversed phase column, at an $1m{\ell}min^{-1}$ flow rate, with a gradient elution of a mixture of methanol, water and acetonitrile. Poncirin and naringin showed good linearity ($R^2$ > 0.999) in relatively wide concentration ranged. The recovery of each compound was 95.81 ~ 101.48% with R.S.D. values less than 1.0%. The application of ultrasound-assisted extraction was shown to be more efficient in extracting poncirin and naringin from Ponciri fructus immaturus. The predicted optimal poncirin and naringin yield were poncirin 2.15%, naringin 1.65% under an extraction temperature of $40^{\circ}C$, an extraction time of 10 min in a solvent of 70% methanol.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.3
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• pp.244-249
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• 2011

A sensitive and rapid high-performance liquid chromatographic-tandem mass spectrometric (HPLC/MS/MS) assay was developed for the determination of soyasaponins in soybean. Among soyasaponins, soyasaponin I was isolated and characterized from methanol extracts of soybean as analytical standards and the development of a new analytical procedure for quantification of its content in various cultivars. The structures of these compound was elucidated by $^1H$, $^{13}C$ NMR experiments and by mass spectrometric analysis. Aqueous ethanol extracts of soybean samples were injected on an Agilent XDB-C18 column ($4.6mm{\times}50mm$, $1.8{\mu}m$) with a mobile phase consisting of 10 mM ammonium acetate-acetonitrile, a flow rate of 0.3 mL/min and a total run time of 8 min. Detection was performed by mass spectrometer bin the multiple reaction monitoring (MRM) mode with negative electrospray ionization (ESI) m/z at 941 ${\rightarrow}$ 615 for soyasaponin I. In the 9 soybean samples, contents of soyasaponin I ranged from 205 to 726 mg/kg, and correlated negatively with seed size.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.3
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• pp.83-89
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• 2011

Diesel engines can produce higher fuel efficiency and lower $CO_2$ emission, they are subject to ever more stringent emission regulation. However, there are two major emission concerns fo diesel engines like such as particulate matter (PM) and nitrogen oxides (NOx). Moreover, it is not easy to satisfy the regulations on the emission of NOx and PM, which are getting more strengthened. One of the solutions is to apply the new combustion concept using multistage injection such as HCCI and PCCI. The other solution is to apply after-treatment systems. For example, lean NOx trap catalyst, Urea-SCR and others have various advantages and disadvantages Especially, Urea-SCR system have advantages such as a high conversion efficiency and a wide operation conditions. Hence the key factor to implementation of Urea-SCR technology, good mixing of urea(Ammonia) and gas, reducing Ammonia slip. Urea mixer components are required to facilitate evaporation and mixing because the liquid state of urea poses significant barriers for evaporation, and the distance to mixer is the most critical that affect mixer performance. In this study, to find out the distance from injector to mixer and simulation factor, a laser diagnostics and high speed camera are used to analyze urea injector spray characteristics and to present a distribution of urea solution in transparent manifold In addition, Droplet Uniformity Index is calculated from the acquired images by using image processing method to clarify the distribution of spray.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.5
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• pp.386-393
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• 2008

The Sulfur-iodine(SI) thermochemical cycle is one of the most promising methods for massive hydrogen production. For the purpose of continuous operation of SI cycle, phase separation characteristics into two liquid phases ($H_2SO_4$-rich phase and $HI_x$-rich phase) were directly investigated via Bunsen reaction. The experiments for Bunsen reaction were carried out in the temperature range, from 298 to 333 K, and in the $I_2/H_2O$ molar ratio of $0.109{\sim}0.297$ under a continuous flow of $SO_2$ gas. As the results, solubility of $SO_2$, decreased with increasing the temperature, had considerable influence on the global composition in the Bunsen reaction system. The amounts of impurity in each phase(HI and $I_2$ in $H_2SO_4$-rich phase and $H_2SO_4$ in $HI_x$-rich phase) were decreased with increasing $H_2SO_4$ molar ratio and temperature. To control the amounts of impurity in $HI_x$-rich phase, temperature is a factor more important than $I_2/H2_O$ molar ratio. On the other hand, the affinity between $HI_x$ and $H_2O$ was increased with increasing $I_2/H2_O$molar ratio.

• Journal of ILASS-Korea
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• v.22 no.4
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• pp.210-217
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• 2017

A gasoline direct injection engine has an intake air temperature can be lowered by the fuel vaporization in the combustion chamber increase the volume efficiency is high compression ratio. Therefore, study for injection rate and characteristics which influence mixture formation in combustion chamber is important. Movement of the injector needle has a direct effect on the injection of the fuel, such as formation of cavitation, the fuel injection rate, etc. Therefore, recent studies on the dynamic characteristics of the injector considering the movement of the needle have been reported, but it takes a lot of time and cost to experimentally confirm the movement of the needle inside the injector. In this study, AMESim, a commercial 1-D code, and Star-CCM+, a 3-D CFD code, were used to predict the dynamic performance of the injector with needle motion. In order to predict the movement of the needle under the high pressure, the result of the surface pressure distribution according to the movement of the needle was derived by using the morphing technique of flow analysis. In addition, we predicted the injection rate of the injector considering the movement of the needle in conjunction with the 1-D code. The injection rate of the injector was measured by the BOSCH's method and the results were similar to those of the simulation results. This method can predict the injection rate and injection characteristics and this result is expected to be used to predict the performance of gasoline direct injection engines with low cost and time in the future.