• Journal of Korean Society for Atmospheric Environment
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• 제19권E4호
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• pp.169-175
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• 2003

The effect of gas composition on the discharge characteristics and the ozone production in silent discharge (SD) process was investigated. The major gas components, $N_2$, $O_2$, and $H_2O$ influence the discharge properties according to their relative magnitude of ionization thresholds and electron affinities. The generated amount of ozone increased with the discharge energy by increasing the electron mean energy. The higher oxygen content injected, the higher ozone produced. A small amount of water vapor significantly lowered the discharge onset voltage by the ionization threshold decreasing effect and high electrical conductivity. However, the further increase of water vapor contributes to decrease the electron density by the electron affinity The addition of water greatly reduced the ozone generation through the formation of OH radical and the catalytic ozone destruction process.

• 한국지하수토양환경학회지:지하수토양환경
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• 제21권1호
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• pp.80-85
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• 2016

Acoustic cavitation can induce various sonochemical effects including pyrolysis and radical reactions and sonophysical effects including microjets and shockwave. In environmental engineering field, ultrasound technology using sonochemical effects can be useful for the removal and mineralization of recalcitrant trace pollutants in aqueous phase as one of emerging advanced oxidation processes (AOPs). In this study, the effect of liquid height, the distance from the transducer to the water surface, on sonochemical oxidation reactions was investigated using KI dosimetry. As the liquid height/volume increased (40~400 mm), the cavitation yield steadily increased even though the power density drastically decreased. It was found that the enhancement at higher liquid height conditions was due to the formation of standing wave field, where cavitation events could stably occur and a large amount of oxidizing radicals such as OH radicals could be continuously provided.

• 약학회지
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• 제49권5호
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• pp.416-421
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• 2005

Cudrania tricuspidata Bereau (Moraceae) have been used for anti-inflammatory, anti-hepatotoxic, anti-hyper­tensive and anti-diabetic activities. In order to investigate the efficacy of antioxidant activity, the bio-activity guided fraction and isolation of Biologically active substance were performed. $H_{2}O,\;30\%,\;60\%,\;100%$ MeOH and acetone fractions were examined on the antioxidant activity by DPPH method. It was shown that $30\%,\;60\%,\;100\%$ MeOH fractions have sig­nificantly antioxidant activity. From $30\%$ MeOH fraction, two dihydroflavonoid glycosides dihydroquercetin 7-O-$\beta$-D-glu­copyranoside (I), dihydrokaempferol 7-O-$\beta$-D-glucopyranoside (V) were isolated and $60\%$ MeOH fraction, six flavonoids including quercetin 3-O-$\alpha$-L-rhamnopyranosyl($1\rightarrow6$)-$\beta$-D-glucopyranoside (II), quercetin 3-O-$\beta$-D-glucopyranoside (III), quercetin 7-O-$\beta$-D-glucopyranoside (IV), kaempferol 3-O-$\alpha$-L-rhamnopyranosyl($1\rightarrow6$)-$\beta$-D-glucopyranoside (VI), kaempferol 3-O-$\beta$-D-glucopyranoside (VII), kaempferol 7-O-$\beta$-D-glucopyranoside (VIII) were isolated. To investigate the antioxidant activities of each compounds, we measured radical scavening activity with DPPH method and anti-lipid per­oxidative efficacy on low density lipoprotein (LDL) with TBARS assay. Four compounds of quercetin glycosides (I, II, III, IV) showed significant antioxidant activity.

• 한국식품영양학회지
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• 제24권1호
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• pp.85-93
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• 2011

Job's tears(Coix lachryma-jobi L.) chungkukjang powder and wheat bran powder were added to American cookies for practical use as healthy compounds. We examined the antioxidant activity and quality characteristics of cookies prepared with different amounts(as ratios of 10%, 20%, 25% to the flour quantity) of Job's tears chungkukjang & wheat bran powder. The antioxidant activity was estimated by DPPH free radical scavenging activity, the total phenolic compounds content and flavonoid content in Job's tears chungkukjang & wheat bran powder and cookies. The quality characteristics of Job's tears chungkukjang & wheat bran powder American cookie were estimated in terms of bulk density, pH of the dough, spread ratio, color, texture profile analysis, proximate composition, and sensory evaluations. While the spread ratio and the total polyphenol contents, flavonoid contents and DPPH free radical scavenging activity of cookies significantly increased, pH, hardness and L value of the cookies decreased with increasing Job's tears chungkukjang & wheat bran powder(p<0.01). The consumer acceptability score for the 10~20% Job's tears chungkukjang & wheat bran powder American cookie ranked significantly(p<0.05) higher than those of the other groups in texture andoverall preference. This suggests that Job's tears chungkukjang and wheat bran powder are good ingredient candidates for increasing consumer acceptability and functionality of cookies.

• 약학회지
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• 제50권6호
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• pp.351-357
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• 2006

Polygoni Radix (Polygonaceae) has been used as renal disoder hematopoietic, menstrual irregularity and antiaging in Korean folk medicine. Specially aerial parts has been used for insomnia and sedative agent. In order to investigate the efficacy of antioxidant activity on these aerial parts, the bio-activity guided fraction and isolation of physiologically active substance were performed. H$_2$O, 30%, 60%, 100% MeOH were examined antioxidant activity by DPPH method. It was revealed that 30%, 60% MeOH fractions have significantly antioxidant activity. From 60% MeOH fraction, six known flavonoid glycosides (quercetin, quercetin 3-O-${\beta}$-D-galactopyranosyl-4'-O-glucopyrano side-3'-methyl ether, quercetin 3-O-${\alpha}$-L-rhannopyranoside, quercetin 3-O- ${\alpha}$-L-rhamnopyranoside-4'-methylethor, quorcetin 3-O-${\beta}$-D-galactopyranoside, quercetin 3-O-${\beta}$-D-galactopyranoside) and 3,4-Oihydrocinnarnic acid were isolated. To investigate the antioxidant activities of each com-pounds, we measured radical scavening activity with DPPH method and anti-lipid peroxidative efficacy on low density lipo-protein (LDL) with TBARS assay and anti-acetylcholinestrase activity with Ellman's Test. Four compounds (ll, IV Vl, Vll) of quercetin glycosides showed significant activity.

• International Journal of Automotive Technology
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• 제2권2호
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• pp.77-83
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• 2001

Effect of ethene on the $DeNO_X$ conversion process in a simulated diesel engine operating conditions was investigated experimentally and theoretically. With the addition of even a small amount of ethene the NO to $NO_2$ conversion enhances greatly. The energy required to convert one NO molecule is 27 eV with 250 ppm ethene added, while 137 eV without ethene at 473 K. The effect of energy density, temperature, and the initial concentrations of ethene and oxygen are also discussed and the results show that the increase of the mentioned parameters lead to the promotion of NO oxidation. A kinetic model used in this study shows good agreement with the experimental result. Byproducts like formaldehyde ($CH_2$ 0) and methyl nitrite ($CH_3$ ONO) predicted by model calculation are broken up into CO and $H_2O$ eventually when high energy is delivered to the gas mixture. Sensitivity analysis shows that the main reactions of NO oxidation when ethene is added we: $HO_2+ NO \arrow NO_2 + OH, RO_2 + NO \arrow NO_2 + RO$, where R is a hydrocarbon radical. Also the direct oxidizing reaction of NO with O cannot be neglected.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.141-141
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• 2013

We have generated the needle-typed nonthermal plasma jet by using an Ar gas flow at atmospheric pressure. Diagnostics of electron temperature anddensity is critical factors in optimization of the atmospheric plasma jet source in accordance with the gas flow rate. We have investigated the electron temperature and density of plasma jet by selecting the four metastable Ar emission lines based on the atmospheric collisional radiative model and radial profile characteristics of current density, respectively. The averaged electron temperature and electron density for this plasma jet are found to be ~1.6 eV and ~$3.2{\times}10^{12}cm^{-3}$, respectively, in this experiment. The densities of OH radical species inside the various bio-solutions are found to be higher by about 4~9 times than those on the surface when the argon bioplasma jet has been bombarded onto the bio-solution surface. The densities of the OH radicalspecies inside the DI water, DMEM, and PBS are measured to be about $4.3{\times}10^{16}cm^{-3}$, $2.2{\times}10^{16}cm^{-3}$, and $2.1{\times}10^{16}cm^{-3}$, respectively, at 2 mm downstream from the surface under optimized Ar gas flow 250 sccm.

• 한방재활의학과학회지
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• 제30권4호
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• pp.41-53
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• 2020

Objectives The purpose of this study was to investigate the effects of Silbi-san on the antioxidant and fat accumulation inhibition and to analyze the anti-obesity effect by analyzing the changes in serum lipid composition in obese mice. Methods We compared contents of phytochemicals like total polyphenols and total flavonoid and antioxidant activities such as 2,2-dipheny-1-picrylhydrazyl and 2.2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging activity. After Silbi-san in 3T3-L1 cells in vitro and mouse adipose tissue ex vivo, we quantified intracellular triglyceride accumulation and lipolysis. Moreover, the anti-obesity activity though inhibiting pancreatic lipase were analyzed. In 3T3-L1 cells, morphological changes showed that control cells had many lipid while cells treated with Silbi-san had less lipid accumulation. 30% EtOH Silbi-san treatment also suppressed the fat absorption by inhibiting the activity of pancreatic lipase and led to high lipolysis through promoting glycerol release. The experimental group was divided into four groups: Normal group fed normal feed, Control group fed 60% high fat diet (HFD) and distilled water, drug group fed 60% high fat diet and 200 mg/kg of Silbi-san water extract, drug group fed 60% HFD and 200 mg/kg of Silbi-san 30% ethanol extract. Results Serum total cholesterol content and serum low density lipoprotein-cholesterol content were significantly decreased in the Silbi-san extract group compared to the control group, serum high density lipoprotein-cholesterol content was significantly increased in Silbi-san extract group. Conclusions In this study, the antioxidant and fat accumulation inhibitory effects of Silbi-san were confirmed.

• 한국물환경학회지
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• 제26권2호
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• pp.303-310
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• 2010

Recently distinguished AOP means technology resolving organic compounds in water to harmless compounds such as $CO_2$ and $H_2O$ by creating OH radical ($OH{\cdot}$) with more powerful oxidation than general oxidants. It has merits which the 2nd pollution is not caused since it uses solar energy, sludge doesn't take place, it can be applied to high-density waste water and it oxidizes non-biodegradable organic compounds more easily. The purpose of the study was to examine about removable characteristics of phenol which was a non-biodegradable organic matter with UV/$O_3$/Catalyst processes which is one out of AOP and to present applicability of photocatalyst and the optimum conditions of treatment. The study regarded initial phenol concentration, initial pH, photocatalyst amount and flow as its conditions. As the results, the test had the highest removable efficiency (92%) when initial phenol concentration was 100 mg/L, initial pH 7, photocatalyst amount 6L and flow 1.5 mg/min. The removable efficiency was increased as much as initial phenol concentration was increased, when initial pH was 7 (neutrality), photocatalyst amount was increased and flow was increased. It was checked that the optimum HRT was 12 hours. Therefore, phenol is enough removable with UV/$O_3$/Catalyst process and its prospect in the future is expected.

• 상하수도학회지
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• 제18권3호
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• pp.392-400
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• 2004

This research uses the $TiO_2$/UV process to verify the most suitable condition and possibility to dispose dyeing wastewater that contains pigment and a large amount of pollutants. For this, this research has enforced experiments that compare photo adsorption, photolysis, and photo catalyst oxidation reaction, and also evaluated and analyzed the change of pH and $TiO_2$ dosage, irradiation rates of ultraviolet rays and the dosage change and injection method of $H_2O_2$. According to the results of the dyeing wastewater experiment of storehouse catalyst that uses the new form of $TiO_2$, the photo catalyst oxidation reaction proved to be more effective than photo adsorption and photolysis; 35%, 21% in the case of $TCOD_{cr}$ and 39%, 28% in the case of chromaticity. Taking into consideration the reaction time, amount of photo catalyst reaction and irradiation amount of ultraviolet rays, the decomposition efficiency of pH change proved to be most effective at pH 4. On the whole, the acidity area proved to be effective in dyeing water exclusion than neutral and alkalinity areas. Having evaluated the influence of $TiO_2$ dosage, not only does the decomposition efficiency continuously improve as the $TiO_2$ dosage increases but the shielding effect does not occur also when the $TiO_2$ is at a fixed state. The influence of ultraviolet irradiation amount concluded in the result that as the ultraviolet irradiation amount increases the decomposition efficiency continually increased, but in the case of chromaticity when the irradiation amount was higher than 37.8mW/cm2 the removal efficiency is slowed remarkably. The influence of $H_2O_2$ dosage evaluation reached the results that although the decomposition efficiency increases with the increase of $H_2O_2$ dosage, when above 150mg (total dosage: 1200mg) $H_2O_2$ consumes OH radical itself and reduces the decomposition efficiency. Also in the case of the $H_2O_2$ injection method rather than injecting in the whole amount of $H_2O_2$ (1200mg) needed at the beginning all at once, injecting divided quantities of $H_2O_2$ whenever the electric current density falls below 10mgfl reduces the wases of OH radical due to an excess of $H_2O_2$ and in tum heightens the decomposition efficiency.