• Journal of Korean Society of Environmental Engineers
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• v.22 no.5
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• pp.869-877
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• 2000

A mechanism of ozonation of simulated soil slurry contaminated by phenanthrene and benzo[a]pyrene has been studied under various conditions. The effects of soil media(BS, S, GB), radical scavenger, ozone input ratio(0.17~0.73mg/min), bicarbonate ion, and humic acid were investigated, BS showed the highest removal efficiency in media tested. The generation of OH-radical via the catalytic decomposition of ozone on active sites of the natural sand was confirmed by OH-radical scavenger experiments. The enhanced removal efficiency by OH-radical was indirectly quantified to be about 22%. As initial concentration of humic acid(as sodium salt) was increased, pseudo first-order rate constant ($k_o$) of phenanthrene was decreased from $1.37{\times}10^{-2}s^{-1}$ to $0.53{\times}10^{-2}s^{-1}$. The amount of ozone required to oxidize 80% of the initial mass of phenanthrene(10mg/kg) and benzo[a]pyrene(10mg/kg) was 67.2mg/kg-soil and 48.0mg/kg-soil, respectively.

• Journal of Energy Engineering
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• v.19 no.4
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• pp.221-227
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• 2010

In this study, we consider gas generation characteristics on pyrolysis of eco-fuel which were made by mixing of Pitch Pine and Lauan sawdust as biomass and polyethylene, polypropylene, polystyrene as municipal plastic wastes with catalyst in fixed bed reactor. From the result of higher heating value(HHV) measurement and of ultimate analysis, the heating value of plastic wastes and a hydrogen content in plastic sample are higher than biomass. An activation energy was reduced by a catalyst addition. However the catalyst content influence over 5 wt% was insignificant. The yield of hydrogen from gasification of biomass containing plastic wastes such as polyethylene, polypropylene and polystyrene were obtained higher than that of sole biomass. The high temperature and mixture ratio of catalyst conditions induced to high hydrogen yield in most of the samples. As the influence of catalyst, the hydrogen yield by catalytic reaction was higher than non-catalytic reaction. We confirmed that Ni-$ZrO_2$ catalyst is more active in increasing the hydrogen yield in comparison with that of carbonate catalyst. The maximum hydrogen yield was 65.9 vol.%(Pitch Pine / polypropylene / 20 wt.% Ni-$ZrO_2$(1:9) at $900^{\circ}C$).

• Journal of the Korean Institute of Gas
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• v.21 no.6
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• pp.52-60
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• 2017

In diffusion process exhaust line during semiconductor manufacturing process, In order to improve the transportation efficiency in the piping by removing "The reaction by-product, $ZrO_2$ and The unreacted material, TEMAZ, TMA, $O_3$, etc" and "Powder being deposited", the piping temperature was raised to $80^{\circ}C$ or more by using the heater jacket, and the bellows at the rear end of the vacuum pump ruptured. So conducted a case study and try to prevent the similar accidents from occurring through case studies. The causes of the accident were analyzed as follows: the inflow of outside air due to the generation of a gap on the suction side of the vacuum pump and heating the pipe with the heater jacket resulted in the overpressure in the pipe due to the volumetric expansion of the gas generated by decomposition of the unreacted TEMAZ, It can be assumed that the most vulnerable bellows of the piping has been ruptured. In order to prevent such accidents, This study is aimed to identify the cause of pipeline rupture accident and to establish safety measures for the prevention of similar accidents by evaluating physical hazards of TEMAZ, which is assumed to be the cause of pipe rupture accident.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.5
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• pp.379-386
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• 2021

This study was undertaken to develop a cascade-type continuous culture system (CCCS) that combines both ICT and biotechnology (BT), for the mass production of microalgae. This system is capable of maintaining the essential culture conditions of pH, temperature, carbon dioxide, and illuminance control, which are key parameters for the growth of microalgae, and is economical for producing microalgae regardless of the season or location. It has the added advantage of providing stable and high productivity. In the current study, this system was applied to culture microalgae for 71 days, with subsequent analysis of the experimental data. The initial O.D. of the culture measured from incubator 1 was 0.006. On the 71st day of culture, the O.D.s obtained were 0.399 (incubator 1), 0.961 (incubator 2), 0.795 (incubator 3), and 0.438 (incubator 4), thereby confirming the establishment of continuous culture. Thus, we present a smart-farm based on ISMC (in-situ monitoring and control) for a mass culture method. We believe that this developed technology is suitable for commercialization, and has the potential to be applied to hydroponics-based cultivation of microalgae and cultivation of high-value-added medicinal plants as well as other plants used in functional foods, cosmetics, and medical materials.

• Journal of Life Science
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• v.29 no.9
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• pp.977-985
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• 2019

Aster yomena (Kitam.) Honda is an edible vegetable and perennial herb belonging to the Asteraceae family, and has been used for a long time for the prevention and treatment of various diseases. Although leaf extracts of A. yomena are known to have antioxidant and anti-inflammatory effects, accurate efficacy assessments are still inadequate. In this study, we investigated whether the antioxidant efficacy of ethanol extract of A. yomena leaf (EEAY) is correlated with the anti-inflammatory effect in RAW 264.7 macrophages. The results showed that EEAY significantly inhibited the hydrogen peroxide ($H_2O_2$)-induced growth inhibition in RAW 264.7 cells, which was associated with increased expression of nuclear factor erythroid 2-related factor-2 (Nrf2) and heme oxygenase-1 (HO-1). EEAY pretreatment also effectively prevented $H_2O_2$-induced reactive oxygen species generation and apoptosis through inhibition of caspase-3 activation and poly (ADP-ribose) polymerase degradation. Additionally, EEAY significantly increased the expression and production of interleukin-10, a representative anti-inflammatory cytokine, which was associated with increased expression of toll-like receptor 4 and myeloid differentiation factor 88 at transcriptional and translational levels. Furthermore, the increased production of nitric oxide (NO) by lipopolysaccharide was markedly abolished under the condition of EEAY pretreatment, and the inhibitory effect of NO production by EEAY was further increased by hemin, an HO-1 inducer. Overall, our results suggest that EEAY is able to activate the Nrf2/HO-1 signaling pathway to protect RAW 264.7 macrophages from oxidative and inflammatory stress.

• Journal of Plant Biotechnology
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• v.5 no.3
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• pp.143-148
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• 2003

Bax, a mammalian pro-apoptotic member of the Bcl-2 family induces cell death when expressed in yeast. To investigate whether Bax expression can induce cell death in plant, we produced transgenic Arabidopsis plants that contained murine Bax cDNA under control of a glucocorticoid-inducible promoter. Transgenic plants treated with dexamethasone, a strong synthetic glucocorticoid, induced Bax accumulation and cell death, suggesting that some elements of cell death mechanism by Bax may be conserved among various organisms. Therefore, we developed novel yeast genetic system, and cloned several Plant Bax Inhibitors (PBIs). Here, we report the function of two PBIs in detail. PBI1 is ascorbate peroxidase (sAPX). Fluorescence method of dihydrorhodamine123 oxidation revealed that expression of Bax in yeast cells generated reactive oxygen species (ROS), and which was greatly reduced by co-expression with sAPX. These results suggest that sAPX inhibits the generation of ROS by Bax, which in turn suppresses Baxinduced cell death in yeast. PBI2 encodes nucleoside diphosphate kinase (NDPK). ROS stress strongly induces the expression of the NDPK2 gene in Arabidopsis thaliana (AtNDPK2). Transgenic plants overexpressing AtNDPK2 have lower levels of ROS than wildtype plants. Mutants lacking AtNDPK2 had higher levels of ROS than wildtype. $H_2O_2$ treatment induced the phosphorylation of two endogenous proteins whose molecular weights suggested they are AtMPK3 and AtMPK6. In the absence of $H_2O_2$ treatment, phosphorylation of these proteins was slightly elevated in plants overexpressing AtNDPK2 but markedly decreased in the AtNDPK2 deletion mutant. Yeast two-hybrid and in vitro protein pull-down assays revealed that AtNDPK2 specifically interacts with AtMPK3 and AtMPK6. Furthermore, AtNDPK2 also enhances the MSP phosphorylation activity of AtMPK3 in vitro. Finally, constitutive overexpression of AtNDPK2 in Arabidopsis plants conferred an enhanced tolerance to multiple environmental stresses that elicit ROS accumulation in situ. Thus, AtNDPK2 appears to playa novel regulatory role in $H_2O_2$-mediated MAPK signaling in plants.

• Tunnel and Underground Space
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• v.22 no.1
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• pp.69-76
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• 2012

Theoretical backgrounds on the experimental methods of explosive welding, explosive forming and shock consolidation of powders are introduced. Explosive welding experiments of titanium (Ti) and stainless steel (SUS 304) plate were carried out. It was revealed that a series of waves of metal jet are generated in the contact surface between both materials; and that the optimal collision velocity and collision angle is about 2,100~2,800 m/s and $15{\sim}20^{\circ}$, respectively. Also, explosive forming experiments of Al plate were performed and compared to a conventional press forming method. The results confirmed that the shock-loaded Al plate has a larger curvature deformation than those made using conventional press forming. For shock consolidation of powders, the propagation behaviors of a detonation wave and underwater shock wave generated by explosion of an explosive are investigated by means of numerical calculation. The results revealed that the generation and convergence of reflected waves occur at the wall and center position of water column, and also the peak pressure of the converged reflected waves was 20 GPa which exceeds the detonation pressure. As results from the consolidation experiments of metal/ceramic powders ($Fe_{11.2}La_2O_3Co_{0.7}Si_{1.1}$), shock-consolidated $Fe_{11.2}La_2O_3Co_{0.7}Si_{1.1}$ bulk without cracks was successfully obtained by adapting the suggested water container and strong bonding between powder particles was confirmed through microscopic observations.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.1
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• pp.55-62
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• 2012

The present paper investigates the performance of the KOH aqueous solution as an absorbent to capture carbon dioxide ($CO_2$). The chemical absorption was carried out according to consecutive reactions that are generated in the order of $K_2CO_3$ and $KHCO_3$. The overall absorption was completed with following the physical absorption. When the absorption was conducted with the KOH as the limiting reactants in batch a reactor, $K_2CO_3$ production rate was the 1st order reaction for $OH^-$. However, $KHCO_3$ generation reaction was independent of the $CO_3^{2-}$ concentration and the rate was calculated to be $0.18gCO_2/min$ for all KOH absorbents, which is the same value of the reaction rate using $K_2CO_3$ aqueous solution as the absorbents. The overall $CO_2$ capture ratio of the 5% KOH absorbent was estimated to be 19% and the individual value in section 1 and 2 was 57 and 12%, respectively. The amount of $CO_2$ absorbed in the solution was very slightly less than the theoretical value, which was ascribed to the side reaction that produces $K_2CO_3{\cdot}KHCO_3{\cdot}1.5H_2O$ during the reaction and the consequent diminish in $CO_2$ absorption in the KOH solution.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.61.2-61.2
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• 2015

In the past decades, green energy, such as solar energy, wind power, hydropower, biomass energy, geothermal energy, and so on, has been widely investigated and developed to solve energy shortage. Recently, organic solar cells have attracted much attention, because they have many advantages, including low-cost, flexibility, light weight, and easy fabrication [1-3]. Organic solar cells are as a potential candidate of the next generation solar cells. In this abstract, to improve the power conversion efficiency and the stability, the inverted polymer solar cells with various structures were developed [4-6]. The novel cell structures included the P3HT:PCBM inverted polymer solar cells with AZO nanorods array, with pentacene-doped active layer, and with extra P3HT interfacial layer and PCBM interfacial layer. These three difference structures could respectively improve the performance of the P3HT:PCBM inverted polymer solar cells. For the inverted polymer solar cells with AZO nanorods array as the electronic transportation layer, by using the nanorod structure, the improvement of carrier collection and carrier extraction capabilities could be expected due to an increase in contact area between the nanorod array and the active layer. For the inverted polymer solar cells with pentacene-doped active layer, the hole-electron mobility in the active layer could be balanced by doping pentacene contents. The active layer with the balanced hole-electron mobility could reduce the carrier recombination in the active layers to enhance the photocurrent of the resulting inverted polymer solar cells. For the inverted polymer solar cells with extra P3HT and PCBM interfacial layers, the extra PCBM and P3HT interfacial layers could respectively improve the electron transport and hole transport. The extra PCBM interfacial layer served another function was that led more P3HT moving to the top side of the absorption layer, which reduced the non-continuous pathways of P3HT. It indicated that the recombination centers could be further reduced in the absorption layer. The extra P3HT interfacial layer could let the hole be more easily transported to the MoO3 hole transport layer. The high performance of the novel P3HT:PCBM inverted polymer solar cells with various structures were obtained.

• Journal of Satellite, Information and Communications
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• v.9 no.3
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• pp.27-32
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• 2014

A doppler shift is generated by moving a transmitter or receiver operated in communication systems. The doppler frequency shift between a transmitter and a receiver or the frequency offset present in transceivers must be removed to get the wanted system performance. FTS is used for preventing an accident from operating abnormally and for guaranteeing public protection. A launching vehicle's initial velocity is very fast in order to escape the earth and the amount of doppler shift is large. Recently many studies to adopt the next generation FTS are ongoing. To introduce new FTS, the effects of doppler shift on the performance of the new FTS must be studied. In this paper the doppler effect caused by launching vehicle's velocity affecting the performance of FTS receiver is investigated into two cases, one is for EFTS as a digital FTS and the other is for FTS using a tone signal. Noncoherent DPSK and noncoherent CPFSK are considered as the modulation methods of EFTS. In the cases of the doppler frequency shift of 200Hz present in EFTS using noncoherent DPSK and noncoherent CPFSK are simulated. Simulation results show that $E_b/N_o$ of 0.5dB deteriorates in the region of near BER of about $10^{-5}$ in RS coding. And there is no performance variation in $E_b/N_o$ or $E_b/N_o$ is worsened about 0.1dB in the same BER region for the case of using convolutional and BCH coding. Quadrature detector used in FTS using tone signals is not influenced by the doppler frequency shift.