• Title/Summary/Keyword: $H_2O_2$ 산화

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Effect of Cell Size on the High Temperature Oxidation Properties of Fe-Cr-Al Powder Porous Metal Manufactured by Electro-spray Process (정전 분무 공정으로 제조된 Fe-Cr-Al 분말 다공체 금속의 고온 산화 특성에 미치는 기공 크기의 영향)

  • Oh, Jae-Sung;Kong, Young-Min;Kim, Byoung-Kee;Lee, Kee-Ahn
    • Journal of Powder Materials
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    • v.21 no.1
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    • pp.55-61
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    • 2014
  • Fe-Cr-Al powder porous metal was manufactured by using new electro-spray process. First, ultra-fine fecralloy powders were produced by using the submerged electric wire explosion process. Evenly distributed colloid (0.05~0.5% powders) was dispersed on Polyurethane foam through the electro-spray process. And then degreasing and sintering processes were conduced. In order to examine the effect of cell size ($200{\mu}m$, $450{\mu}m$, $500{\mu}m$) in process, pre-samples were sintered for two hours at temperature of $1450^{\circ}C$, in $H_2$ atmospheres. A 24-hour thermo gravimetric analysis test was conducted at $1000^{\circ}C$ in a 79% $N_2$ + 21% $O_2$ to investigate the high temperature oxidation behavior of powder porous metal. The results of the high temperature oxidation tests showed that oxidation resistance increased with increasing cell size. In the $200{\mu}m$ porous metal with a thinner strut and larger specific surface area, the depletion of the stabilizing elements such as Al and Cr occurred more quickly during the high-temperature oxidation compared with the 450, $500{\mu}m$ porous metals.

Influences of Potassium Fluoride (KF) Addition on the Surface Characteristics in Plasma Electrolytic Oxidation of Marine Grade Al Alloy (해양환경용 알루미늄 합금의 플라즈마 전해 산화 시 표면 특성에 관한 불화칼륨(KF)의 영향)

  • Lee, Jung-Hyung;Kim, Seong-Jong
    • Journal of the Korean institute of surface engineering
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    • v.49 no.3
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    • pp.280-285
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    • 2016
  • In this study, we investigated the influences of potassium fluoride(KF) addition on the surface characteristics of plasma electrolytic oxidation(PEO) coating produced on Al alloy. The PEO of marine grade Al alloy(5083 grade) was conducted in KOH 1g/L solution adding different concentrations of KF(0, 1 and 2 g/L) under a galvanostatic regime. With KF addition, unusual behavior was observed on the voltage-time characteristic curves, which can be characterized by the following process: (i) initial rapid increase in voltage (ii) a short plateau after 1st breakdown (iii) gradual increase in voltage (iv) intermittent fluctuation of voltage after 2nd breakdown. The SEM observation revealed irregular surface morphology with KF addition, as compared with one formed without KF addition, which had a reticulate structure. The XRD analysis detected the formation of aluminium hydroxide fluoride hydrate($H_{4.76}Al_2F_{3.24}O_{3.76}$) on surface grown by PEO process with KF. Particularly, at very early stage of the process (~ 120 s), thin film was formed having nanoporous structure, and F element was confirmed on surface by EDS analysis. The thickness and surface roughness of the coating increased with increasing KF concentration. As a result, KF addition was found to be less beneficial influences on PEO of marine grade Al alloy, and therefore needs further research to improve its capability.

Anti-Oxidative, Anti-Inflammatory, and Anti-Melanogenic Activities of Endlicheria Anomala Extract (Endlicheria anomala (Nees) Mez 추출물의 항산화, 항염증 및 미백 활성)

  • Jin, Kyong-Suk;Lee, Ji Young;Kwon, Hyun Ju;Kim, Byung Woo
    • Microbiology and Biotechnology Letters
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    • v.41 no.4
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    • pp.433-441
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    • 2013
  • In this study, the anti-oxidative, anti-inflammatory, anti-melanogenic activities of Endlicheria anomala (Nees) Mez methanol extract (EAME) were evaluated by use of in vitro assays and cell culture model systems. The results revealed that EAME scavenges various radicals such as 1,1-diphenyl-2-picryl hydrazyl hydrogen peroxide induced reactive oxygen species, and lipopolysaccharide induced nitric oxide. Furthermore, EAME induced the expression of anti-oxidative enzymes such as heme oxygenase 1, thioredoxin reductase 1, NAD(P)H dehydrogenase 1, and their upstream transcription factor, nuclear factor-E2-related factor 2. Moreover, EAME inhibited in vitro DOPA oxidation and 3-isobutyl-1-methylxanthine induced melanogenesis in B16F10 cells. Its anti-melanogenic activity will have originated from the inhibition of tyrosinase enzyme activity and melanogenesis related protein expression. Taken together, these results provide the important new insight that E. anomala possesses various biological activities such as anti-oxidative, anti-inflammatory, and anti-melanogenic. Therefore, it might be utilized as a promising material in the fields of nutraceuticals and cosmetics.

Evaluation of Antioxidant, Cytoprotective and Antimicrobial Properties of Polygoni multiflori Radix Extract, Fractions and Its Major Constituent (하수오 추출물, 분획물 및 주성분의 항산화, 세포 보호 및 항균 활성에 관한 평가)

  • Shin, Hyuk Soo;Kim, Minwoo;Song, Jerry;Lee, Junseok;Ha, Yoonjeong;Jeon, Young Hee;Kim, Ji Woong;Lee, Yun Ju;Park, Soo Nam
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.44 no.4
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    • pp.407-417
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    • 2018
  • In this study, the antioxidant, cytoprotective and antimicrobial activities of 50% ethanol extract of Polygoni multiflori Radix (PMR) and its ethyl acetate fraction were evaluated to confirm the applicability as a functional ingredient. The activities of the major constituent of PMR were verified and 2, 3, 5, 4′-tetrahydroxystilbene 2-O-${\beta}$-D-glucoside (THSG) was confirmed to be the main component of extract and fraction using HPLC-DAD, LC-EIS-MS analysis. The phenolic and THSG contents of the ethyl acetate fraction were 11.1- and 3.0-folds higher than those of the ethanol extract, respectively. As a result of the DPPH assay and that of luminol dependent chemiluminescence assay in $Fe^{3+}$-EDTA/H2O2 system. the ethylacetate fraction was superior to the ethanol extract in free radical and ROS scavenging activities. Especially, the ethyl acetate fraction and THSG exhibited the similar scavenging activity like L-ascorbic acid in ROS scavenging activity. The ethyl acetate fraction perceived the most potent cytoprotective effect against oxidative damage of erythrocytes induced by photosensitization reaction, followed by the ethanol fraction, THSG and that of (+)-${\alpha}$-tocopherol, which was used as a positive control. Antimicrobial activities were evaluated by disc diffusion and broth microdilution assay against S. aureus, E. coli, P. aeruginosa and C. albicans. In particular, the antibacterial activity of the extract and fraction against S. aureus was superior to that of methyl paraben. Taken together, our results suggest that PMR could be used as a natural ingredient for antioxidant, cytoprotective and antimicrobial activities.

Comparison of Anti-oxidative Activity in a Single Serving Size of the Commercial Coffees and Teas

  • Kim, Tae-Hun;Lee, Seulgi;Seo, Jin Woo;Bing, Sun Hye;Kim, Jong Im;Kwon, Eui-Ra;Jo, Gune-Hee;Lee, Jae-Myean;Choi, Joon Sig
    • Journal of Food Hygiene and Safety
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    • v.32 no.6
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    • pp.460-469
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    • 2017
  • The aim of this work was to study the comparison of anti-oxidative activity in a single serving size of commercial coffees and teas. Commercial regular coffees and teas, including, brand regular coffees ($BC_A$, $BC_B$, $BC_C$, $BC_D$, and $BC_E$), green tea ($GT_A$, $GT_B$, $GT_C$, and $GT_D$), black tea ($BT_A$, $BT_B$, and $BT_C$), pu-erh tea ($PT_A$, $PT_B$, and $PT_C$), chamomile tea ($CT_A$, $CT_B$, and $CT_C$), peppermint tea ($P_A$, $P_B$, and $P_C$), polygonatum odoratum tea ($POT_A$, $POT_B$, and $POT_C$), and jujube tea ($JT_A$, $JT_B$, and $JT_C$) were assayed for the levels of ascorbic acid, caffeine, total content of polyphenols and flavonoids, and ability to scavenge free radicals, using two in vitro antioxidant assays. The scavenging abilities of $BC_A$ and $BC_C$ were $664.91{\pm}48.87mg$ ascorbic acid equivalent/serving size and $624.36{\pm}16.18mg$ ascorbic acid equivalent/serving size, respectively. The four beverage samples ($BC_A$, $BC_C$, $GT_D$, and $BT_A$) significantly reduced the production of reactive oxygen species (ROS) and intracellular oxidative stress induced by $H_2O_2$. These results suggest that the beverages possess significant radical scavenging ability, which may be due to the presence of antioxidants. Furthermore, the significant reducing level of ROS evidences the potential antioxidant effects of these beverages in human cells.

A Case of Acute Respiratory Distress Syndrome Caused by Nitric Acid Inhalation (질산(Nitric Acid) 증기 흡입에 의한 급성호흡곤란증후군 1예)

  • Kim, Dae Sung;Yoon, Hye Eun;Lee, Seung Jae;Kim, Yong Hyun;Song, So Hyang;Kim, Chi Hong;Moon, Hwa Sik;Song, Jeong Sup;Park, Sung Hak
    • Tuberculosis and Respiratory Diseases
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    • v.59 no.6
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    • pp.690-695
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    • 2005
  • Nitric acid is an oxidizing agent used in metal refining and cleaning, electroplating, and other industrial applications. Its accidental spillage generates oxides of nitrogen, including nitric oxide (NO) and nitrogen dioxide ($NO_2$), which cause chemical pneumonitis when inhaled. The clinical presentation of a nitric acid inhalation injury depends on the duration and intensity of exposure. In mild cases, there may be no symptoms during the first few hours after exposure, or the typical symptoms of pulmonary edema can appear within 3-24 hours. However, in cases of prolonged exposure, progressive pulmonary edema develops instantaneously and patients may not survive for more than 24 hours. We report a case of a 44-year-old male who was presented with acute respiratory distress syndrome after nitric acid inhalation. He complained of cough and dyspnea of a sudden onset after inhaling nitric acid fumes at his workplace over a four-hour period. He required endotracheal intubation and mechanical ventilation due to fulminant respiratory failure. He was managed successfully with mechanical ventilation using positive end expiratory pressure and systemic corticosteroids, and recovered fully without any deterioration in his pulmonary function.

Component Analysis and Reproduction of a Brown Solid Cosmetic Excavated from Tomb of Princess Hwahyeop (화협옹주 출토 화장품(갈색 고체) 성분 분석 및 재현연구)

  • Lee, Chaehoon;You, Song-e;Lee, Hanhyoung;Kim, Hyoyun;Kim, Seongmi;Chung, Yongjae
    • Journal of Conservation Science
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    • v.36 no.5
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    • pp.430-439
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    • 2020
  • This study focused on analyzing solid brown cosmetic residues that were excavated from the tomb of the Hwahyeop princess. The cosmetics had been buried in 1752 in Cheonghwa Baekja (small porcelain jars) within a Huigwakham (a stone box sealed with lime). A literature search and chemical analyses of the relics were conducted at the National Palace Museum of Korea. Based on the results of these analyses, raw materials and manufacturing methods for reproduction of the cosmetic were selected and then cream-form cosmetics were prepared. Aging tests using heat, ultraviolet (UV) radiation, and CO2 were carried out to emulate the deterioration of the excavated cosmetics. Further chemical analyses and functionality tests were performed to evaluate changes from the tests and the effect as a cosmetic. As heat aging progressed, among the reproduced cosmetics, the one which has a high proposition of oil showed a color difference value of 32; the oxidation of oils involved chemical changes in O-H and C=C groups. As the cosmetic cream deteriorated under UV aging, the pH value became acidic. The result of the functional coverage test of the reproduced cosmetic cream was lower than the standard coverage ratio of modern cosmetics.

Removal of Color and non-biodegradable organic matter from biologically treated effluent by coagulation. (응집에 의한 생물학적 처리수의 색도 및 난분해성 유기물 제거)

  • Seo, Tae-Gyeong;Park, Sang-Min;Park, No-Baek;Jeon, Hang-Bae
    • Proceedings of the Korea Water Resources Association Conference
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    • 2008.05a
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    • pp.859-863
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    • 2008
  • 축산폐수, 침출수 등의 고농도 폐수를 생물학적으로 처리할 경우 최종 방류수는 강한 색도를 띠며 고분자량의 유기물질을 다량 함유한다. 이는 생물학적으로 분해하기 어려운 유기성 복합체와 생화학적 반응에 의한 중간생성물로 색도를 띠는 천연유기물질(NOM)을 포함한다. 생물학적 처리수의 색도는 심미적인 불안감, 방류수역의 수질오염 및 공중보건상의 잠재적 위해성을 갖는다. 또한, 수자원 이용측면에서 정수처리공정에서의 약품투입량 증가와 특히, 소독부산물 생성이라는 잠재적 문제점이 뒤따른다. 따라서 이러한 문제점을 해소하기 위한 생물학적 2차 처리수의 후속처리가 요구되며, 실제로 난분해성 유기물과 색도를 제거하기 위한 흡착, 막 분리, 고급산화(AOP) 및 화학적 응집 등의 물리-화학적 공정에 대한 연구가 수행되어왔다. 특히, 화학적 응집은 무기응집제 또는 고분자중합체(Polymer)를 이용하여 콜로이드성 입자와 색도를 띠는 난분해성 유기물을 전기적 불안정화를 유도함으로서 흡착 및 응집과정을 통해 제거하는 공정으로 많은 연구자들에 의해 연구되어왔다. 그러나 난분해성 유기물과 색도제거는 대상원수의 성상과 화학적 특성 등에 따라 각각의 제거효율과 최적 운전조건이 상이하게 나타난다. 화학적 응집공정은 비교적 높은 제거효율을 보이지만, 운전 및 유지관리의 기술적 어려움, 경제적 비효율성 등으로 인하여 적용에 어려움을 겪고 있는 실정이다. 본 논문에서는 생물학적 혐기-호기성 공정에서 방류되는 축산폐수의 2차 처리수를 대상으로 화학적 응집에 의한 색도 및 난분해성 유기물의 제거거동을 고찰하였다. 대상 처리수의 $TCOD_{Cr}$ 농도는 평균 410 mg/L인 반면, $BOD_5$는 7-15 mg/L 범위로 난분해성 유기물을 다량 함유하고 있음을 알 수 있었다. 이에 황산알루미늄(Aluminium sulfate; $Al_2(SO_4){\cdot}14H_2O$)과 염화철(ferric chloride)의 무기응집제를 이용하여 자 테스트(jar test)를 수행한 결과, 동일한 응집제 주입량에서 염화철의 유기물 제거 효율이 높은 것으로 나타났다. 황산알루미늄과 염화철의 경우 각각의 응집제 주입율 5.85mM에서 89%, 7.03mM에서 97.5%의 최대 유기물 제거효율을 보여주었으며, 이 때 최종 pH는 4.0-5.6 범위이었다. 한편, 대상 원수 내의 콜로이드성 입자 또는 용존성 유기물의 작용기(functional group)는 일반적으로 음으로 하전 되어 있어 응집에 의해 잘 제거되지 않는 특성을 가지고 있다. 따라서 과량의 응집제를 주입하여 다가의 양이온성 금속염을 흡착시켜 전기적으로 중화시키고, 생성된 침전성 수화물 내에 포획 또는 여과시켜 제거하게 된다. 이 때, 금속염 수화종의 전하밀도가 응집효율에 영향을 주는 것으로 알려져 있는데, 다가의 양이온은 전기적 이중층(Double layer) 압축에 의한 불안정화를 향상시킬 수 있기 때문에다. 또한, 2가 금속염은 색도유발물질과 흡착하여 humate 또는 fulvate 등의 착화합물(complex)을 형성시켜 응집효율을 향상시킬 수 있다. 따라서 본 연구에서는 생물학적 2차 처리수의 화학적 응집처리에 있어서 알루미늄염 등의 다가이온 첨가가 응집에 미치는 영향을 관찰하고, 후속되는 플록형성 및 침전공정에 의한 제거효율을 비교, 평가함으로써 2차 처리수로부터 난분해성 유기물과 색도를 보다 효과적이고 경제적으로 제거할 수 있는 최적인자를 도출하고자 하였다.

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Effect of Post-annealing on the Interfacial adhesion Energy of Cu thin Film and ALD Ru Diffusion Barrier Layer (후속 열처리에 따른 Cu 박막과 ALD Ru 확산방지층의 계면접착에너지 평가)

  • Jeong, Minsu;Lee, Hyeonchul;Bae, Byung-Hyun;Son, Kirak;Kim, Gahui;Lee, Seung-Joon;Kim, Soo-Hyun;Park, Young-Bae
    • Journal of the Microelectronics and Packaging Society
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    • v.25 no.3
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    • pp.7-12
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    • 2018
  • The effects of Ru deposition temperature and post-annealing conditions on the interfacial adhesion energies of atomic layer deposited (ALD) Ru diffusion barrier layer and Cu thin films for the advanced Cu interconnects applications were systematically investigated. The initial interfacial adhesion energies were 8.55, 9.37, $8.96J/m^2$ for the sample deposited at 225, 270, and $310^{\circ}C$, respectively, which are closely related to the similar microstructures and resistivities of Ru films for ALD Ru deposition temperature variations. And the interfacial adhesion energies showed the relatively stable high values over $7.59J/m^2$ until 250h during post-annealing at $200^{\circ}C$, while dramatically decreased to $1.40J/m^2$ after 500 h. The X-ray photoelectron spectroscopy Cu 2p peak separation analysis showed that there exists good correlation between the interfacial adhesion energy and the interfacial CuO formation. Therefore, ALD Ru seems to be a promising diffusion barrier candidate with reliable interfacial reliability for advanced Cu interconnects.

Effects of Radish Leaves Powder on Hepatic Antioxidative System in Rats Fed High-Cholesterol Diet (무청이 고콜레스테롤 식이 흰쥐 간조직의 항산화계에 미치는 영향)

  • Rhee, Soon-Jae;Ahn, Jung-Mo;Ku, Kyung-Hyung;Choi, Jeong-Hwa
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.34 no.8
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    • pp.1157-1163
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    • 2005
  • The current study examined the effects of radish loaves powder on hepatic antioxidative system in rats fed high-cholesterol diet. Sprague-Dawley male rats weighing 100$\pm$10 g were randomly assigned to normal group (N group), normal diet with 5$\%$ radish leaves powder supplemented group (NR group) and high-cholesterol groups, which were sub-divided into radish leaves powder free diet group (HC group) and 2.5$\%$ (HRL group), 5$\%$ (HRM group), 10$\%$ (HRH group) radish leaves powder supplemented groups. Hepatic super oxide dimutase activity was no significant differences. Hepatic glutathione peroxidase activity was sig-nificantly increased in 5$\%$, 10$\%$ radish leaves powder supplemented groups. Hepatic hydrogen peroxide contents in cytosol were no significantly differences Hepatic hydrogen peroxide contents in mitochondria were sig-nificantly reduced in radish leaves powder supplemented groups. Hepatic superoxide radical contents in mi-crosome were significantly reduced in radish leaves powder supplemented groups. Hepatic superoxide radical contents in mitochondria were significantly reduced in 5$\%$, 10$\%$ radish leaves powder supplemented groups. Hepatic TBARS values were significantly reduced in 5$\%$, 10$\%$ radish leaves powder supplemented groups. Hepatic lipofuscin contents were no significant difference in high-cholesterol groups. Hepatic carbonyl values were significantly reduced in 5$\%$, 10$\%$ radish leaves powder supplemented groups among high-cholesterol groups. The results indicate that radish leaves may reduce oxidative damage by activating antioxidative de-fense system of liver in rats fed high-cholesterol diets.