• 제목/요약/키워드: Oxidized powder

검색결과 110건 처리시간 0.019초

M ssbauer 효과에 의한 제주도 찰흙의 함철 광물의 열적 거동과 상변환에 관한 연구 (A Study on the Thermal Behavior and Phase Transformation of Iron-bearing Minerals in Clay of Cheju Island by M ssbauer Effect)

  • 강동우;김두철;류재연;고정대;홍성락;송관철
    • 한국광물학회지
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    • 제10권2호
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    • pp.148-161
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    • 1997
  • Based on the X-ray powder diffraction (XRD) and M ssbauer spectroscopy, the thermal behavior and phase transformations of two clays are investigated for raw and fired conditions, which are collected from Kwangryeongli and Ildo district in Cheju Island. M ssbauer spectra at room temperature and 20for two clays show that paramagnetic Fe3- is the structural iron of the layer silicate and ferrihydrite, and superparamagnetic goethite has about 50% of total iron contents. The XRD peaks of hematite for the fired clays appear from 80$0^{\circ}C$ in Kwangryeongli clay and from $600^{\circ}C$ in Ildo district clay, respectively. The structural Fe2+ was completely oxidized into Fe3- at 40$0^{\circ}C$ for Kwangryeongli clay and 50$0^{\circ}C$~$600^{\circ}C$ for Ildo district clay, respectively. The structural Fe2+ was completely oxidized into Fe3- at 40$0^{\circ}C$. For the temperature ranging from 40$0^{\circ}C$ to $700^{\circ}C$~80$0^{\circ}C$, two fired clays exhibit the dehydroxylation of the clay mineral. A disintegration of the clay mineral structure is observed from $700^{\circ}C$~80$0^{\circ}C$ to 110$0^{\circ}C$, followed by the onset and spread of vitrification process. It is also shown that well-crystallized hematite phase is formed at the temperature higher than 110$0^{\circ}C$ and the relative absorption area decreases, which might be related to the recrystallization of alluminosilicate matrix.

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Rat 간장의 산화적 스트레스 및 세포막 유동성에 미치는 실크 피브로인의 영향 (Effects of Silk Fibroin in Oxdative Stress and Membrane Fluidity in the Liver of SD Rats)

  • 최진호;김대익;박수현;김동우;이광길;여주홍;김정민;이용우
    • 한국잠사곤충학회지
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    • 제42권1호
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    • pp.58-64
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    • 2000
  • This study was designed to investigate the effects of silk fibroin powder (Mw 500) on oxidative stress and membrane fluidity in liver membranes of rats. Sprague-Dawley (SD) male rats (160$\pm$10g) were fed basic diet (control group), and experimental diets (SEP-2.5 and SFP-5.0 groups) added 2.5 and 5.0 g/kg BW/day for 6 weeks. Cholesterol levels resulted in a significant decrease (12.1% and 9.0%, respectively) in the liver mitochondria and microsomes of SEP-5.0 group compared with control group. Membrane fluidity as significantly increased (16.1% and 16.5%, 5.8% and 17.4%) in the liver mitochondria and microsomes were significantly inhibited (16.1% and 18.3%, 8.1% and 15.1%, respectively) at the SFP-2.5 and SEP-5.0 groups compared with control group. Induced oxygen radicals (BOR) in liver mitochondria and microsomes were significantly inhibited (16.1% and 18.3%, 8.1% and 15.1%, respectively) at the SFP-2.5 and SEP-5.0 groups compared with control group. Induced oxygen radicals (IOR) in liver microsomes were significantly inhibited (17.0% and 26.6%, respectively) at the SFP-2.5 and SFP-5.0 groups compared with control group, but IOR in liver mitochondria was significantly inhibited about 12.3% at the SWP-400 group only compared with control group. Lipid peroxide (LPO) levels were significantly decreased (8.3% and 18.0%, 13.4% and 18.4%, respectively) in the liver mitochondria and microsomes of SFP-2.5 and SFP-5.0 groups compared with control group. Oxidized protein (OP) levels were dose-dependently decreased (5.4% and 11.6%, 19.0% and 24.4%, respaectively) in the iver mitochondria and microsomes of SFP-2.5 and SFP-5.0 groups compared with control group. These results suggest that administration of SFP may play an effective role in attenuating an oxidative stress and increasing a membrane fluidity in liver membranes.

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뇌조직의 활성산소 및 그 제거효소에 미치는 실크 피브로인의 영향 (Effects of Silk Fibroin on Oxygen radicals and Their Scavenger Enzymes in Brain of SD Rats)

  • 최진호;김대익;박수현;김정민;조원기;이광길;여주홍;이용우
    • 생명과학회지
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    • 제10권4호
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    • pp.340-346
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    • 2000
  • This study was designed to investigate the effects of silk fibroin(Mw 500) powder (SFP) on oxygen radicals and the scavenger enzymes in brain membranes of rats. Spragu-Dawley(SD) male rats(160${\pm}$10g) were fed basic diet(control group), and experimental diets(SFP-2.5 and SFP-5.0 groups) added 2.5 and 5.0g/kg BW/day for 6 weeks. Hydroxyl radical($.$OH) levels resulted in a decreases(6.6% and 9.7%, 2.8% and 11.9%, respectively) in brain mitochondria and microsomes of SFP-2.5 and SFP-5.0 groups compared with control group, but were significantly decreased in these membrances of SFP-5.0 group only. Superoxide radical (O2) levels were a slightly decreased (2.0% and 9.1%, respectively) in brain cytosol of SFP-2.5 and SFP-5.0 groups compared with control group. Lipid peroxide(LPO) levels were significantly decreased (12.9% and 21.9%, 13.2% and 22.5%, respectively) in brain mitochondria and microsomes of SFP-2.5 and SFP-5.0 groups compared with control group. Oxidized protein (OP) levels were significantly decreased (16.7% and 15.7%, respectively) in brain microsomes of SFP-2.5 and SFP-5.0 group compared with control group, but significantly difference between in brain mitochondria of these two groups could not be obtained. Mn-SOD activities were remarkably increased (11.2% and 24.2%, respectively) in mitochodria of SFP-2.5 and SFP-5.0 groups. CuZn-SOD activities were effectively increased (7.7% and 19.6%, respectively) in brain cytosol of SFP-2.5 and SFP-5.0 groups, but significant difference between control and SFP-2.5 groups could be not obtained. GSHPx activities were considerably increased (5.3% and 11.7%, respectively) in brain cytosol of SFP-2.0 and SFP-5.0 groups compared with control group. There results suggest that anti-aging effect of silk fibroin may play an effective learning and memory role in a attenuating a oxidative stress and increasing a scavenger enzyme activity in brain membranes.

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노화억제작용에 미치는 다시마(Laminaria japonica)와 후코이단 성분의 영향 (Effects of Sea Tangle (Laminaria japonica) and Fucoidan Components on Anti-aging Action)

  • 최진호;김대익;박수현;김동우;이종수;유종현;정유섭
    • 생명과학회지
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    • 제9권4호
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    • pp.439-452
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    • 1999
  • This study was designed to investigate the effects of sea tangle (Laminaria japonica) extract and fucoidan components on anti-aging action. Sprague-Dawley(SD) male rats (210$\pm$5g) were fed experimental diets Dasi-Ex group: sea tangle extract powder of 4.0% added to control diet; Fuco-I, II and III groups: funcoidan powder of 1, 2 and 3% added to Dasi-Ex group for 45 days. Hydroxyl radical (.OH) formations were significantly inhibited (10-20% and 25-30%) in serum and brain mitochondria of Dasi-Ex and Fuco-I, II and III groups compared with control group. Significant differences in .OH formations of brain mitochondria in Dasi-Ex and Fuco-I groups could not be obtained, but.OH formations of brain microsomes resulted in a significant decrease (15-20%) in Fuco-II and III groups compared with control group. Basal oxygen radical (BOR) formations were significantly decreased about 10% and 13-15% in brain mitochondria of Dasi-Ex and Fuco-I group, and Fuco-II, III groups, and also decreased about 10% and 15-20% in brain microsomes of Dasi-Ex and Fuco-I groups, and Fuco-II, III groups. LPO levels of brain mitochondria and microsomes were significantly inhibited about 10% in Dasi-Ex and Fuco-I, II groups and 15% in Fuco-III groups. Oxidized proteins (>C=O) were significantly inhibited about 10% in serum of Dasi-Ex and Fuco-I, II, III groups and brain mitochondria of Dasi-Ex group, while remarkably inhibited (30~35%) in brain mitochondria of Fuco-I, II and III groups. Nitric oxide (NO) levels were significantly inhibited (12~15%) in serum of Fuco-I, II and III groups, but there no significant difference in serum NO levels of Dasi-Ex group. Superoxide dismutase (SOD) activities were remarkably increased (30~ 60%) in serum of Fuco-I, II and III groups, but there were no significant differences in SOD activities in serum of Dasi-Ex group. Catalase (CAT) activities were significantly increased about 20% in serum of Dasi-Ex and Fuco-I, II, III groups. Mn-SOD activities in brain mitochondria were significantly increased about 17% in Dasi-Ex group, while remarkably increased 26~36% in Fuco-I, II, III groups. Cu,Zn-SOD activities in brain cytosol were dose-dependently of fucoidan increased 10%, 12% and 18%, respectively, compared with control group. These results suggest that anti-aging effects of fucoidan may play a pivotal role in attenuating a various age-related changes such as chronic degenerative disease and senile dementia.

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사용후핵연료의 연소도 변화에 따른 산화 및 OREOX 공정에서 핵분열기체 방출 특성 (Release Characteristics of Fission Gases with Spent Fuel Burn-up during the Voloxidation and OREOX Processes)

  • 박근일;조광훈;이정원;박장진;양명승;송기찬
    • 방사성폐기물학회지
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    • 제5권1호
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    • pp.39-52
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    • 2007
  • 사용후핵연료의 건식 재가공을 위한 핵연료 원격 제조공정중 분말제조를 위한 산화 및 OREOX(산화 환원공정)열처리 공정으로부터 $^{85}Kr$$^{14}C$ 핵분열기체의 방출거동을 정량적으로 평가하였다. 특히 사용후핵연료의 평균 연소도가 $27,000{\sim}65,000\;MWd/tU$ 범위내에서 연소도 변화에 따른 핵분열기체의 방출 분율은 측정한 실험결과와 ORIGEN 코드로부터 계산된 초기 inventory를 상호 비교하여 구하였다. $500^{\circ}C$ 1차 산화공정(voloxidation)에서 $^{85}Kr$$^{14}C(^{14}CO_2)$의 시간에 따른 방출거동은 $UO_2$ 핵연료의 $U_3O_8$으로의 분말화 정도와 밀접한 관련이 있는 것으로 보이며, 입계(grain-boundary)에 분포된 핵분열기체가 대부분 방출되는 것으로 여겨진다. 산화분말을 이용한 OREOX 공정으로부터 핵분열기체의 높은 방출율은 $700^{\circ}C$의 환원공정에서 온도 증가에 의한 기체 확산 및 $UO_2$으로의 환원에 의한 U 원자 이동성 증가에 의존하며 주로 inter-grain 및 intra-grain에 분포된 핵분열기체가 방출된 것으로 판단된다. 일차 산화공정시 $^{85}Kr$$^{14}C$ 핵분열기체의 방출 분율은 핵 연료 연소도가 증가함에 따라 높게 나타났고 방출 분율 범위는 총 inventory의 $6{\sim}12%$정도며, 산화분말의 OREOX 공정처리시 잔류 핵분열기체 대부분이 방출되는 것으로 보인다. 아울러 사용후핵 연료로부터 핵분열기체의 제거를 위해서는 고온 환원분위기보다는 산화에 의한 분말화가 더 효과적인 것으로 여겨진다.

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한국에서 유통 중인 산화형 염모제의 중금속 농도에 관한 연구 (A Study on Heavy Metal Concentrations of Oxidized Hair Coloring Products in Korea Market)

  • 최채만;홍미선;이윤정;김화순;김현정;김정헌;채영주
    • 대한화장품학회지
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    • 제39권3호
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    • pp.241-249
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    • 2013
  • 2012년 1월에서 10월 사이에 전국에서 유통 중인 산화형 염모제(1제) 125개 제품에서 납(Pb), 비소(As), 카드뮴(Cd), 크롬(Cr), 망간(Mn), 니켈(Ni), 구리(Cu)의 농도 측정과 국산, 수입산 및 헤나별, 성상별, 색상별로 비교해 봄으로써 이에 관련된 분야의 기초자료를 제공하고자 본 연구를 시행하였다. 분석된 전체 염모제의 평균 중금속 농도는 납 0.211 ${\mu}g/g$, 비소 0.051 ${\mu}g/g$, 카드뮴 0.008 ${\mu}g/g$, 크롬 0.954 ${\mu}g/g$, 망간 6.250 ${\mu}g/g$, 니켈 0.591 ${\mu}g/g$, 구리 0.544 ${\mu}g/g$으로 측정되었으며 납, 비소의 경우 우리나라 화장품 안전기준 등에 관한 규정에서 허용기준인 납 20 ${\mu}g/g$, 비소 10 ${\mu}g/g$보다 낮은 수치이다(식품의약품안전처 고시 제2013-24 호). 또한 헤나 염모제는 통계적으로 유의한 차이를 보였으며(p < 0.05), 납 1.264 ${\mu}g/g$, 비소 0.267 ${\mu}g/g$, 카드뮴 0.025 ${\mu}g/g$, 크롬 4.055 ${\mu}g/g$, 망간 72.044 ${\mu}g/g$, 니켈 3.076 ${\mu}g/g$, 구리 4.640 ${\mu}g/g$으로 국산 및 수입 염모제보다 높았다. 염모제의 성상별 중금속 농도는 통계적으로 유의한 차이를 보였으며(p < 0.05), 크림과 액체 타입에서 크롬이 각각 0.708 ${\mu}g/g$, 0.478 ${\mu}g/g$로 가장 높았고, 분말타입에서는 망간이 60.041 ${\mu}g/g$로 높았다. 염모제의 색상별 중금속 농도는 통계적으로 유의한 차이를 보이지 않았으며, 노란색의 경우 납, 크롬이 높은 평균 농도를 보였고, 적색과 분홍색의 염모제는 크롬, 갈색과 흑색은 망간이, 녹색은 니켈이 높은 평균 농도를 나타내었다.

저진공 분위기 전기방전소결에 의해 제조된 다공성 Ti-6Al-4V 임플란트의 표면특성 연구 (Surface Characteristics of Porous Ti-6Al-4V Implants Fabricated by Electro-Discharge-Sintering in a Low Vacuum Atmosphere)

  • 현창용;허재근;이원희
    • 한국재료학회지
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    • 제16권3호
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    • pp.178-182
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    • 2006
  • A single electro-discharge-sintering (EDS) pulse (1.0 kJ/0.7 g), from a $300{\mu}F$ capacitor, was applied to atomized spherical Ti-6Al-4V powder in a low vacuum to produce porous-surfaced implant compacts. A solid core surrounded by a porous layer was formed by a discharge in the middle of the compact. XPS (X-ray photoelectron spectroscopy) was used to study the surface characteristics of the implant material. C, O, and Ti were the main constituents, with smaller amounts of Al, V, and N. The implant surface was lightly oxidized and was primarily in the form of $TiO_2$ with a small amount of metallic Ti. A lightly etched EDS implant sample showed the surface form of metallic Ti, indicating that EDS breaks down the oxide film of the as-received Ti-6Al-4V powder during the discharge process. The EDS Ti-6Al-4V implant surface also contained small amounts of aluminum oxide in addition to $TiO_2$. However, V detected in the EDS Ti-6Al-4V implant surface, did not contribute to the formation of the oxide film..

패각 분말기반 과산화칼슘 제조와 산소 유리 특성 (Preparation of Calcium Peroxide Originated from Oyster Shell Powder and Oxygen Releasing Ability)

  • 유길선;안지은;조대철;권성현
    • 한국환경과학회지
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    • 제27권9호
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    • pp.763-770
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    • 2018
  • Bioremediation in situ is heavily dependent on the oxygenic environment which would privide the dwelling microorganism with sufficient oxygen. The situation could be easily resolved with supply of an Oxygen Releasing Compound (ORC). In this paper we prepared that sort of material out of oyster shell powder (mostly calcium carbonate) that prevails every shore areas of the country. We used two different oxidizing methods in the first step of the whole manufacturing process-conventional heating in a furnace and an ultrasound generator to obtain calcium oxide. Then that calcium oxide was further oxidized into calcium peroxide which may release oxygen under a moisturized condition. The oxygen releasing experiments were run to test the performance of our products, and to determine the gas kinetics during the experiments. Interestingly, calcium peroxide derived from ultrasound treatment was much more energy-effective as ORC than that from furnace heating although the heat derived process was better than that of ultrasound in terms of oxygen content and its releasing rate. We also found that most of the data collected from the gas releasing experiments fairly supported an ordinary $1^{st}$ order kinetics to oxygen concentration, which shaped a sharp discharge of oxygen at the very early moment of each test.

${\gamma}$-$Fe_2O_3$ 세라믹 가스감지소자;비표면이 가스감응성에 미치는 영향 (Effect of Specific urface Area on the Gas Sensitive Properties)

  • 신장욱;박순자
    • 한국세라믹학회지
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    • 제23권5호
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    • pp.1-8
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    • 1986
  • This paper is concerned with a gas sensor composed of semi-conducting ${\gamma}$-$Fe_2O_3$ ceramics made by oxidizing $Fe_2O_3$ sintered body. Acicular $\alpha$-FeOOH powder prepared by precipitation of $FeSO_4$.$7H_2O$ solution was transformed to $FeSO_4$ sintered at 700$^{\circ}$-850$^{\circ}$C for 1 hr. and then oxidized to ${\gamma}$-$Fe_2O_3$ The gas sensitive properties of ${\gamma}$-$Fe_2O_3$ ceramic bodies based on the lectrical resistance change was measured in 0.5-2 vol% $H_2$ and $C_2$ $H_2$ gas at 35$0^{\circ}C$ The specific surface area of sintered specimen largely dependent on the sintering temperature and grain shape directly affected the gas sensitive pro-perties of ${\gamma}$-$Fe_2O_3$gas sensor. Specimens having larger specific surface area showed better sensitivity which means the electrical resistance change due to oxidation and reduction process occurs on ly at the surface of grains microscopically in the ${\gamma}$-$Fe_2O_3$ceramics. Micropores made in $Fe_2O_3$ powder during dehydration of $\alpha$-FeOOH can not prompt the gas sensitive properties of sintered ${\gamma}$-$Fe_2O_3$ because they are sintered or closed in the grains during sintering process and dose not affect the specific surface area of sintered body.

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VLS 합성법을 이용한 ZnO 나노구조의 특성 (ZnO Nanostructure Characteristics by VLS Synthesis)

  • 최유리;정일현
    • 공업화학
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    • 제20권6호
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    • pp.617-621
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    • 2009
  • Zinc oxide (ZnO)을 금(Au)과 fluorine-doped tin oxide (FTO) 촉매로 산화실리콘($SiO_2$) 기판에 산화아연입자 20 nm, $20{\mu}m$를 각각 사용하여 기체-액체-고체(VLS) 합성법으로 성장시켰다. 나노로드의 표면특성, 화학조성, 그리고 결정특성을 엑스레이회절(X-ray diffraction (XRD)), 에너지 분산형 X선 분광기(Energy-dispersive X-ray spectroscopy (EDX)), 표면 방출주사현미경(Field-emission scanning electron microscope (FE-SEM))으로 분석하였다. ZnO의 입자 크기 뿐만 아니라 결정형태가 성장에 크게 영향을 미쳤다. ZnO의 모든 나노구조가 6방정계(六方晶系), 단일결정구조를 가지고 있었다. 최적온도는 $1030^{\circ}C$, 입자크기는 20 nm이다. 그러므로 Au 대신 플루오린 첨가 도핑으로 전기음성도가 증가된 FTO 증착에 의해서 생성된 나노로드는 경제성 있는 대체물질로서의 가치가 있을 것으로 사료된다.