• Journal of Korean Society of Environmental Engineers
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• v.31 no.4
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• pp.308-323
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• 2009

This review paper serves to describe the composition and activity of biological activated carbon (BAC) biofilm which is considered as a progressive process for water treatment. As well as several physical-chemical, biochemical and microbiological analysis methods for characterizing the composition and activity of BAC biofilm, the ability of the biofilm to remove and biodegrade organic matters and pollutants related to other water treatment processes such as pre-ozonation will be reviewed. In this paper, conversion of GAC into BAC, removal mechanism of pollutants, characteristics and affecting factors of BAC biofilm, and modeling of BAC are described in detail. In addition, strategies to control the growth of the BAC biofilm, such as varying the nutrient loading rate, altering the frequency of BAC filter backwashing and applying oxidative disinfection, will be dwelled on related to their respective process control challenges.

• Applied Biological Chemistry
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• v.25 no.4
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• pp.201-205
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• 1982

As a series of study on the removal of astringency and production of tannin substances, this experiment was conducted to investigate changes of tannin contents and microscopic observation on leaves of persimmon(Diospyros kaki L.). Changes of tannin contents of leaves and fruits in Daegu Bansi(astringent variety) were of similar tendency in content of total and soluble tannin during growth. It seemed therefore that tannin contents of leaves in astringent variety were closely concerned with tannin of fruits. But Fuyu(sweet variety) was different from each other during its growth. Histological form of leaves in microscopic observation had similar tendency between astringent and sweet varieties. It was observed that tannin substances were contained in epidermis cells of levels, that tannin substances were transfered in phloems of nerves system, and that tannin cell existed too in the vicinity of nerves system.

• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1201-1207
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• 2020

This study explored whether MXene (Ti₃C₂T_x) could remove radioactive Cs⁺ from model nuclear wastewater. Various adsorption tests were performed and the physical aspects of the interaction were investigated. We varied the MXene dosage, Cs⁺ initial concentration, solution pH, solution temperature and exposure time. MXene adsorption exhibited very fast kinetics, based on the fact that equilibrium was achieved within 1 h. MXene exhibited an outstanding adsorption capacity (148 mg g^-1) at adsorbent and adsorbate concentrations of 5 and 2 mg L^-1, respectively, at neutral pH condition (i.e., pH 7). We explored Cs⁺ adsorption by MXene in the presence of four different ions (NaCl, KCl, CaCl₂ and MgCl₂) and three different organic acids (sodium oleate, oxalic acid, and citric acid). The Cs⁺ removal rate changed in the presence of these components; adsorption of Cs⁺ by MXene thus involved ion exchange, supported by both Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy. We confirmed that MXene was re-usable for at least four cycles. MXene is cost-effective and practical when used to adsorb radionuclides (e.g., Cs⁺) in nuclear wastewater.

• Journal of Environmental Science International
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• v.18 no.1
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• pp.61-72
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• 2009

Fabrication and oxidants production of 3 or 4 components metal oxide electrode, which is known to be so effective to destruct non-biodegradable organics in wastewater, were studied. Five electrode materials (Ru as main component and Pt, Sn, Sb and Gd as minor components) were used for the 3 or 4 components electrode. The metal oxide electrode was prepared by coating the electrode material on the surface of the titanium mesh and then thermal oxidation at $500^{\circ}C$ for 1h. The removed RhB per 2 min and unit W of 3 components electrode was in the order: Ru:Sn:Sb=9:1:1 > Ru:Pt:Gd=5:5:1 > Ru:Sn=9:1 > Ru:Sn:Gd=9:1:1 > Ru:Sb:Gd=9:1:1. Although RhB decolorization of Ru:Sn:Sb:Gd electrode was the highest among the 4 components electrode, the RhB decolorization and oxidants formation of the Ru:Sn:Sb=9:1:1 electrode was higher than that of the 3 and 4 components electrode. Electrogenerated oxidants (free Cl and $ClO_2$) of chlorine type in 3 and 4 components electrode were higher than other oxidants such as $H_2O_2\;and\;O_3$. It was assumed that electrode with high RhB decolorization showed high oxidant generation and COD removal efficiency. OH radical which is electrogenerated by the direct electrolysis was not generated the entire 3 and 4 components electrode, therefore main mechanism of RhB degradation by metal oxide electrode based Ru was considered indirect electrolysis using electrogenerated oxidants.

• Natural Product Sciences
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• v.19 no.4
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• pp.290-296
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• 2013

In preliminary tests, we examined the effect of several fractions isolated from fermented pine needle extract on pacemaker potentials in cultured interstitial cells of Cajal (ICCs) from the mouse colon using a whole cell patch clamp technique. Among these fractions, Fraction 3 (F3) elicited the most powerful depolarization of membrane. Therefore, the aim of the present study was to investigate the effect of F3 obtained from fermented extract of Pinus densiflora needle on pacemaker potentials in ICCs and to establish its mechanism of action. Colonic ICCs generated spontaneous periodic pacemaker potentials in the current-clamp mode. F3 depolarized the membrane and decreased the frequency and amplitude of pacemaker potentials in a dose-dependent fashion. The F3-induced effects on pacemaker potentials were blocked by methoctramine, a muscarinic $M_2$ receptor antagonist, and by glycopyrrolate, a muscarinic $M_3$ receptor antagonist. The F3-induced effects on pacemaker potentials were blocked by external $Na^+$-free solution and by flufenamic acid, a non-selective cation channel blocker, as well as by the removal of external $Ca^{2+}$ and in the presence of thapsigargin, a $Ca^{2+}$-ATPase inhibitor in the endoplasmic reticulum. Taken together, these results suggest that F3 of pine needle extract modulates the pacemaker activity of colonic ICCs by the activation of non-selective cation channels via muscarinic $M_2$ and $M_3$ receptors. And external $Ca^{2+}$ influx and intracellular $Ca^{2+}$ release are involved in F3 actions on ICCs.

• Asian Journal of Turfgrass Science
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• v.25 no.2
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• pp.237-242
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• 2011

The 2011 Japanese Society of Turfgrass Science was divided in oral presentation, sectional meeting and small symposium, and the total 55 subject was announced. The oral presentation was reported physiological ecology of turf, disease and weed; field management; pesticidal activity and spectrum of new turf pesticides. Above all, there was presentation that investigated control method of necrotic ring spot of new turf disease and Cyperus brevifolius, annual bluegrass and mouse-ear chickweed. In addition, the control effect of new registration fungicide (Furametpyr) and herbicides (S-metolachlor, Flucetosulfuron and Foramsulfuron) were announced. There was various information interchange through 4 kinds of subjects of a golf course, ground turf, a urban park greens and ground cover plants greening by the sectional meeting, and the genetic resource of turfgrass discussed by small symposium. Specially, park greens sectional meeting was announced about the radioactive material contaminated on mechanism and effectively removal method of the radioactivity contaminant from public park, school ground and domestic lawn.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.3
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• pp.279-288
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• 2012

The material removal mechanism in machining is significantly affected by the cutting edge geometry. Its effect becomes even more substantial when the depth of cut is relatively small as compared to the characteristic length which represents the shape and size of the cutting edge. Conventionally, radius or focal length has been employed as the characteristic length with the assumption that the shape of cutting edge is round or parabolic. However, in reality, there could be various ways to determine the radius or focal length even for the same tool edge profile, depending on the region to be considered as cutting edge in the measured profile and the constraints to be set in constructing the best fitted circle or parabola. In this regard, the present study proposes various models to determine the characteristic length in terms of radius or focal length. Their physical compatibility are validated by carrying out 2D orthogonal cutting experiments using inserts with a wide range of characteristic length ($30{\sim}180\;{\mu}m$ in terms of radius) and then by investigating the correlation between the characteristic length and the cutting forces. Such validation is based on the common belief that the larger the characteristic length is, the blunter the cutting edge is and the higher the cutting forces are. Interestingly, the results showed that the correlation is higher for the radius or focal length obtained with a constraint that the center of best fitted circle or the focus of the best fitted parabola should be on the bisectional line of the wedge angle of tool.

• The Korean Journal of Physiology and Pharmacology
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• v.10 no.1
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• pp.25-30
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• 2006

Lysophosphatidylcholine (LPC), which accumulates in atherosclerotic arteries, has been reported to inhibit endothelium-dependent relaxation (EDR) in many different species. However, the underlying mechanism of LPC-induced inhibition of EDR is still uncertain. In the present study, we measured simultaneously both isometric tension and cytosolic free $Ca^{2+}$ ($[Ca^{2+}]_i$) in rabbit carotid strips, and examined the effect of LPC on tension and $[Ca^{2+}]_i$. In carotid strips with intact-endothelium, high $K^+$ (70 mM) increased both tension and $[Ca^{2+}]_i$, and cumulative addition of acetylcholine (ACh) from 0.1 to $10{\mu}M$ induced dose dependent increase of $[Ca^{2+}]_i$ with concomitant relaxation. In the presence of L-NAME (0.1 mM), ACh increased $[Ca^{2+}]_i$ without affecting the amplitude of high $K^+-induced$ tension. These ACh-induced change of $[Ca^{2+}]_i$ and tension was abolished by removal of endothelium or 10 nM 4-DAMP (muscarinic receptor antagonist) pretreatment. Pretreatment of LPC ($10{\mu}M$) inhibited ACh ($10{\mu}M$)-induced change of tension and $[Ca^{2+}]_i$ in endothelium-intact carotid artery. On the other hand, LPC had no effect on ACh-induced change of tension and $[Ca^{2+}]_i$ in endothelium denuded artery. In $Ca^{2+}$-free external solution, ACh transiently increased $[Ca^{2+}]_i$, and pretreatment of LPC significantly inhibited ACh-induced transient $[Ca^{2+}]_i$ change. Based on the above results, it may be concluded that LPC inhibits the ACh-induced $[Ca^{2+}]_i$ change through inhibition of $Ca^{2+}$ mobilization in vascular endothelial cells, resulting in decreased production of NO and concomitant inhibition of endotheliumdependent vascular relaxation.

• Journal of the Korean Vacuum Society
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• v.6 no.1
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• pp.85-90
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• 1997

A new ionized sputtering process was developed to fill small trench or via using additional ionizing mechanism of sputtered particles from 32cm $AlCu_x$(x=0.5%) cathode target with rotating magnet, then drawn toward substrate by small negative DC potential. The radial uniformity in RFI magnetron sputtering was studied by plasma diagnosis and appropriate RFI coil design to improve it. Optical emission intensities of excited species. $Ar^{\circ}, \;Ar^+;Al^+, \;Al^{\circ}$ are measured across the radial direction and showed close correlation with deposit's bottom to top thickness ratios in trenches and vias of submicron opening and 1.5 aspect ratio. After increase of the diameter of RF coil from 29 cm to 32 cm and improved the power leading feedthrough symmetry by removal of asymmetric single turn region, there was an increase of uniformity from 7.5% to 1.5% in bottom to top thickness ratio in 0.6 $\mu\textrm{m}$ vias.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.171-171
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• 2009

The electrodes are usually made of a porous mixture of carbon-supported platinum and ionomers. $SnO_2$ particles provide as supports that have been used for DMFCs, and it have high catalytic activities toward methanol oxidation. The main advantage of $SnO_2$ supported electrodes is that it has strong chemical interactions with metallic components. The high activity to a synergistic bifunctional mechanism in which Pt provides the adsorption sites for CO, while oxygen adsorbs dissociative on $SnO_2$. The reaction between the adsorbed species occurs at the Pt/$SnO_2$ boundary. The morphological observations were characterized by FESEM and transmission electron microscopy (TEM). $SnO_2$ particles crystallinity was analyzed by the X-ray diffraction (XRD). The surface bonded state of the $SnO_2$ particles and electrode materials were observed by the X-ray photoelectron spectroscopy (XPS). The electric properties of the Pt/$SnO_2$ catalyst for methanol oxidation have been investigated by the cyclic voltametry (CV) in 0.1M $H_2SO_4$ and 0.1M MeOH aqueous solution. The peak current density of methanol oxidation was increased as the $SnO_2$ content in the anode catalysts increased. Pt/$SnO_2$ catalysts improve the removal of CO ads species formed on the platinum surface during methanol electro-oxidation.