• 한국지하수토양환경학회지:지하수토양환경
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• 제21권6호
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• pp.169-178
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• 2016

The Standards, Measurement and Testing Programme (SM&T-formerly BCR) extraction procedure was applied to fractionate Cr, Cu, Ni, Pb and Zn in 23 top soil samples into: (i) exchangeable phase; (ii) reducible phase; (iii) oxidisable(sulfides and organics bound) phase; and (iv) residual phase. Fractions of Cr and Ni were in the order of residual > oxidisable > reducible > exchangeable phase. The oxidisable phase was identified as dominant for Cu and Pb. Zn had the highest ratio of exchangeable phase in comparision to the other metals. The bioavailability and mobility were assessed to be the greatest for Zn, followed by a decreasing order of Pb, Cu, Ni and Cr. All metal average concentrations in topsoil samples was higher in industrial sites than in agricultural sites. Our results revealed higher concentrations in topsoil samples (0~15 cm) than in sub soils (15~30 cm, 30~60 cm) for most metals at six sites (No. 5, 6, 17, 19, 20, 23). The fractions of exchangeable, reducible ad oxidisable phases showed relatively high correlation with soil pH, Fe/Mn oxide concentrations and organic matter contents, respectively.

• Nutrition Research and Practice
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• 제9권6호
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• pp.579-585
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• 2015

BACKGROUND/OBJECTIVES: Sonchus asper is used extensively as an herbal anti-inflammatory for treatment of bronchitis, asthma, wounds, burns, and cough; however, further investigation is needed in order to understand the underlying mechanism. To determine its mechanism of action, we examined the effects of an ethyl acetate fraction (EAF) of S. asper on nitric oxide (NO) production and prostaglandin-E2 levels in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. MATERIALS/METHODS: An in vitro culture of RAW264.7 macrophages was treated with LPS to induce inflammation. RESULTS: Treatment with EAF resulted in significant suppression of oxidative stress in RAW264.7 macrophages as demonstrated by increased endogenous superoxide dismutase (SOD) activity and intracellular glutathione levels, decreased generation of reactive oxygen species and lipid peroxidation, and restoration of the mitochondrial membrane potential. To confirm its anti-inflammatory effects, analysis of expression of inducible NO synthase, cyclooxygenase-2, tumor necrosis factor-${\alpha}$, and the anti-inflammatory cytokines IL-$1{\beta}$ and IL-6 was performed using semi-quantitative RT-PCR. EAF treatment resulted in significantly reduced dose-dependent expression of all of these factors, and enhanced expression of the antioxidants MnSOD and heme oxygenase-1. In addition, HPLC fingerprint results suggest that rutin, caffeic acid, and quercetin may be the active ingredients in EAF. CONCLUSIONS: Taken together, findings of this study imply that the anti-inflammatory effect of EAF on LPS-stimulated RAW264.7 cells is mediated by suppression of oxidative stress.

• Transactions on Electrical and Electronic Materials
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• 제10권5호
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• pp.152-155
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• 2009

The microstructure and the electrical properties of a ZnO varistor, which was composed of a ZnO-$Bi_2O_3$-$Sb_2O_3$-CoO- $MnO_2$ -NiO-$Nd_2O_3$ system, were investigated at various $Y_2O_3$ addition concentrations. $Y_2O_3$ played a role in the inhibition of the grain growth. As the $Y_2O_3$ content increased, the average grain size decreased from $6.8{\mu}m$ to $4{\mu}m$, and the varistor voltage($V_{1mA}$) greatly increased from 275 to 400 V/mm. The nonlinearity coefficient ($\alpha$) decreased from 72 to 65 with increasing $Y_2O_3$ amount. On the other hand, the leakage current ($I_L$) increased from 0.2 to 0.9 ${\mu}A$. These results confirmed that doping the varistors with $Y_2O_3$ is a promising production route for production of a higher fine-grained varistor voltage ($V_{1mA}$) which can dramatically reduce the size of the varistors.

• 자원리싸이클링
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• 제9권1호
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• pp.63-69
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• 2000

페로망간 분진은 망간계 산화무로 분진내 함유된 불순물을 정제하고 산화도를 조절한다면 망간계 연자성 페라이트로 재활용이 가능하다. 페로망간 분진은 약 7여종의 불순물을 함유하고 있고, 이중 $SiO_2$는 약 9000ppm을 함유하고 있다. 분진내 주요 불순물인 $SiO_2$는 페로망간 분진을 페라이트 재료로 사용할 경우 투자율에 악영향을 미치는 성분으로 알려져 있다. 본 연구는 페로망간 분진을 연자성 페라이트 재료로 재활용하고자 기초 연구로 수행되었으며 특히 분진내 함유된 약 9000ppm의 $SiO_2$량을 500ppm 이하로 줄이고자 하였다. 용융 알칼리 원소 fuitting법을 사용하였으며 이 방법으로는 용융된 알칼리 원소가 페로망간 분진내 $SiO_2$와 결합하여 가용성의 fnt을 형성하고 이 trit은 물침물에 의하여 $SiO_2$를 제거 할 수 있었다. Fritting법에서 KOH, NaOH를 사용한 경우 모두 알칼리 원소 대비 페로망간 분진 혼합중량비는 1.75, $550^{\circ}C$ frittung온도 그리고 1시간의 fritting 시간이 가장 효율적이다.

• 한국환경과학회지
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• 제21권6호
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• pp.667-676
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• 2012

This research investigated to reduce mass of heavy metals in AMD(acid mine drainage) by microbial mats formed on the channel bed. As, Cd, Cu, Fe, Mn and Zn components were monitored in water and microbial mats, at three points (AMD1, AMD2 and AMD3), in a total of six times. Average daily discharge mass of heavy metals was highest in July, Fe component contained more than 76% of total discharge mass. Discharge mass of heavy metals of AMD and heavy metal contents in microbial mats decreased with downstream at channel. Heavy metal components that average daily discharge mass is over 0.5 kg were Fe, Cu and Zn, and they were highest in July. Average removal efficiency of heavy metals in AMD was highest about 21% in Fe, this microbial mats were due to form from precipitation of Fe component in AMD by aerobic iron bacteria. Relative content for As component in microbial mats than AMD was over 16 times, this As components were due to absorb at iron oxide and iron hydroxide on the surface of microbial mats.

• 한국수소및신에너지학회논문집
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• 제10권4호
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• pp.197-210
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• 1999

The hydrogen storage performance and electrochemical properties of $Zr_{1-X}Ti_X(Mn_{0.2}V_{0.2}Ni_{0.6})_{1.8}$(X=0.0, 0.2, 0.4, 0.6) alloys are investigated. The relationship between discharge performance and alloy characteristics such as P-C-T characteristics and crystallographic parameters is also discussed. All of these alloys are found to have mainly a C14-type Laves phase structure by X-ray diffraction analysis. As the mole fraction of Ti in the alloy increases, the reversible hydrogen storage capacity decreases while the equilibrium hydrogen pressure of alloy increases. Furthermore, the discharge capacity shows a maxima behavior and the rate-capability is increased, but the cycling durability is rapidly degraded with increasing Ti content in the alloy. In order to analyze the above phenomena, the phase distribution, surface composition, and dissolution amount of alloy constituting elements are examined by S.E.M., A.E.S. and I.C.P. respectively. The decrease of secondary phase amount with increasing Ti content in the alloy explains that the micro-galvanic corrosion by multiphase formation is little related with the degradation of the alloys. The analysis of surface composition shows that the rapid degradation of Ti-substituted Zr base alloy electrode is due to the growth of oxygen penetration layer. After comparing the radii of atoms and ions in the electrolyte, it is clear that the electrode surface becomes more porous, and that is the source of growth of oxygen penetration layer while accelerating the dissolution of alloy constituting elements with increasing Ti content. Consequently, the rapid degradation (fast growth of the oxygen-penetrated layer) with increasing Ti substitution in Zr-based alloy is ascribed to the formation of porous surface oxide through which the oxygen atom and hydroxyl ion with relatively large radius can easily transport into the electrode surface.

• Preventive Nutrition and Food Science
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• 제19권2호
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• pp.82-88
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• 2014

Yam (Dioscorea batatas Decne.) has long been used as a health food and oriental folk medicine because of its nutritional fortification, tonic, anti-diarrheal, anti-inflammatory, antitussive, and expectorant effects. Reactive oxygen species (ROS), which are known to be implicated in a range of diseases, may be important progenitors of carcinogenesis. The aim of this study was to investigate the modulatory effect of yam on antioxidant status and inflammatory conditions during azoxymethane (AOM)-induced colon carcinogenesis in male F344 rats. We measured the formation of aberrant crypt foci (ACF), hemolysate antioxidant enzyme activities, colonic mucosal antioxidant enzyme gene expression, and colonic mucosal inflammatory mediator gene expression. The feeding of yam prior to carcinogenesis significantly inhibited AOM-induced colonic ACF formation. In yam-administered rats, erythrocyte levels of glutathione, glutathione peroxidase (GPx), and catalase were increased and colonic mucosal gene expression of Cu/Zn-superoxide dismutase (SOD), Mn-SOD, and GPx were up-regulated compared to the AOM group. Colonic mucosal gene expression of inflammatory mediators (i.e., nuclear factor kappaB, inducible nitric oxide synthase, cyclooxygenase-2, tumor necrosis factor alpha, and interleukin-1beta) was suppressed by the yam-supplemented diet. These results suggest that yam could be very useful for the prevention of colon cancer, as they enhance the antioxidant defense system and modulate inflammatory mediators.

• 한국축산시설환경학회지
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• 제8권2호
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• pp.107-110
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• 2002

This study was carried out to investigate the quantity of Holstein dry cow manure excreted and their characteristics. The results obtained in this study were summarized as follow; The average body weight of the Holstein dry cow during experiment was 619.9kg. The feed intake(DM basis) and water consumption was 10.7, 38.6kg/day/head, repectively. The manure production of Holstein dry cow was 44.8kg/day/head (feces 26.9, urine 17.9kg). The moisture content of feces and urine was 84.5%, 95.3%, respectively. Wastewater pollutant concentration of $BOD_5$(Biochemical Oxygen demand), $COD_{Mn}$ (Chemical Oxygen demand), SS(Suspended Solids), T-N(Total Nitrogen) and T-P(Total Phosphorus), excreted from Holstein dry cow was 16,874,55,763, 87,333, 2,353, $368mg/{\ell}$ in feces and 5,621, 8,673, 518, 2,423, $3mg/{\ell}$ in urine, repectively. The fertilizer content of manure, N(Nitrogen), $P_2O_5$(Phosphoric acid) and $K_2O$(Potassium oxide) was 0.24, 0.08, 0.15% in feces and 0.24, 0.001, 0.30% in urine, respectively.

• Bulletin of the Korean Chemical Society
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• 제35권8호
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• pp.2349-2356
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• 2014

The recycling technology by the catalytic conversion is one of the most promising techniques for the $CO_2$ treatment of coal burning power plant flue gases. The conversion of $CO_2$ to valuable product of $CH_4$ can be used as a fuel to run the turbine for electricity generation. Through this technique, the amount of coal needed for the combustion in a gas turbine can be reduced as well as $CO_2$ emissions. Therefore, a series of catalysts based on cerium oxide doped with copper, nickel and manganese were prepared by impregnation method. From the characterization analysis, it showed that the prepared catalysts calcined at $400^{\circ}C$ were amorphous in structure with small particle size in the range below 100 nm. Meanwhile, the catalyst particles were aggregated and agglomerated with higher surface area of $286.70m^2g^{-1}$. By increasing the calcination temperature of catalysts to $1000^{\circ}C$, the particle sizes were getting bigger (> 100 nm) and having moderate crystallinity with lower surface area ($67.90m^2g^{-1}$). From the catalytic testing among all the prepared catalysts, Mn/Ce-75/$Al_2O_3$ calcined at $400^{\circ}C$ was assigned as the most potential catalyst which gave 49.05% and 56.79% $CO_2$ conversion at reaction temperature of $100^{\circ}C$ and $200^{\circ}C$, respectively.

• Journal of Welding and Joining
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• 제13권3호
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• pp.134-146
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• 1995

Aluminium nitride(AlN) is currently under investigation as potential candidate for replacing alumium oxide(Al$_{2}$ $O_{3}$) as a substrate material for for electronic circuit packaging. Brazing of aluminium nitride(AlN) to Cu with Ag base active alloy containing Ti has been investigated in vacuum. Binary Ag$_{98}$ $Ti_{2}$(AT) and ternary At-1wt.%Al(ATA), AT-1wt.%Ni(ATN), AT-1wt.% Mn(ATM) alloys showed good wettability to AlN and led to the development of strong bond between brate alloy and AlN ceramic. The reaction between AlN and the melted brazing alloys resulted in the formation of continuous TiN layers at the AlN side iterface. This reaction layer was found to increase by increase by increasing brazing time and temperature for all filler metals. The bond strength, measured by 4-point bend test, was increased with bonding temperature and showed maximum value and then decreased with temperature. It might be concluded that optimum thickness of the reaction layer was existed for maximum bond strength. The joint brazed at 900.deg.C for 1800sec using binary AT alloy fractured at the maximum load of 35kgf which is the highest value measured in this work. The failure of this joint was initiated at the interface between AlN and TiN layer and then proceeded alternately through the interior of the reaction layer and AlN ceramic itself.