• Title/Summary/Keyword: Natural oxide

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A Study on $SO_2$ Adsorption Characteristics by NMO in a Moving Bed Reactor (NMO를 이용한 이동층반응기에서의 $SO_2$ 흡착특성에 관하 연구)

  • 조기철
    • Journal of Korean Society for Atmospheric Environment
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    • v.16 no.4
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    • pp.399-408
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    • 2000
  • This study evaluated the SO2 adsorption characteristics using a continous moving bed system. Natural manganese oxide (NMO) reaction condition such as L/D the starting time of the NMO feed, feed rate, and flow rate of simulated flue gas, and NMO size were tested. The results showed that optimum L/D was 1.0 in this moving bed system. The higher the feeding rate was the higher the SO2 removal efficiency was and the higher the flow rate of simulated flue gas was the shorter the time to reach the euqilibirum concentration was. The final SO2 con-centration when it reaches the equilibrium concentration was not affected by the starting time of the NMO feed.

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Anthraquinones with Immunostimulating Activity from Cassia tora L.

  • Chung, Ha-Sook
    • Preventive Nutrition and Food Science
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    • v.10 no.3
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    • pp.267-271
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    • 2005
  • Many of plants had been reported having immunostimulating activity. This study reports the immunostimulating activity of Cassia tora L. (Leguminosae) seed, by means of solvent extraction method. Ethanol extract and solvent fractions, n-hexane, chloroform, ethylacetate, n-butanol and aqueous layer of Cassia tora L. seed were tested for immunostimulating activity in vitro. The ethylacetate-soluble fraction caused significant inhibition on the production of nitric oxide by murine macrophages (RAW 264.7), and mouse splenocytes were also stimulated at the concentration of 10 pgfmL. Three anthraquinones, chrysophanol (1), isochrysophanol (2) and aloe-emodin (3) with immunostimulating activity were isolated from the ethylacetate-soluble fraction of Cassia tora L. seed through activity-monitored fractionation and isolation method. These results permit Cassia tora L. to be useful as one the of natural immunostimulating crops.

Mass Transfer Experiments for the Heat Load During In-Vessel Retention of Core Melt

  • Park, Hae-Kyun;Chung, Bum-Jin
    • Nuclear Engineering and Technology
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    • v.48 no.4
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    • pp.906-914
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    • 2016
  • We investigated the heat load imposed on the lower head of a reactor vessel by the natural convection of the oxide pool in a severe accident. Mass transfer experiments using a $CuSO_4-H_2SO_4$ electroplating system were performed based on the analogy between heat and mass transfer. The $Ra^{\prime}_H$ of $10^{14}$ order was achieved with a facility height of only 0.1 m. Three different volumetric heat sources were compared; two had identical configurations to those previously reported, and the other was designed by the authors. The measured Nu's of the lower head were about 30% lower than those previously reported. The measured angular heat flux ratios were similar to those reported in existing studies except for the peaks appearing near the top. The volumetric heat sources did not affect the Nu of the lower head but affected the Nu of the top plate by obstructing the rising flow from the bottom.

Facile Preparation of 2-Arylbenzo[b]furan Molecules and Their Anti-inflammatory Effects

  • Hwang, Jung-Woon;Choi, Da-Hye;Jeon, Jae-Ho;Kim, Jin-Kyung;Jun, Jong-Gab
    • Bulletin of the Korean Chemical Society
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    • v.31 no.4
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    • pp.965-970
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    • 2010
  • An efficient and practical preparation of 2-arylbenzo[b]furan molecules including natural egonol, XH-14, ailanthoidol, and unnatural derivatives is demonstrated using Sonogashira coupling, iodine induced cyclization and Wittig reaction. Anti-inflammatory effects of the prepared benzo[b]furans were examined in lipopolysaccharide (LPS)-stimulated RAW 264-7 macrophages. The results showed that ailanthoidol, XH-14 and three other unnatural derivatives (9-10, 13) inhibited significantly the production of inflammatory mediator nitric oxide without showing cytotoxicity.

Electrical Conductivity of Chemically Reduced Graphene Powders under Compression

  • Rani, Adila;Nam, Seung-Woong;Oh, Kyoung-Ah;Park, Min
    • Carbon letters
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    • v.11 no.2
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    • pp.90-95
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    • 2010
  • Carbon materials such as graphite and graphene exhibit high electrical conductivity. We examined the electrical conductivity of synthetic and natural graphene powders after the chemical reduction of synthetic and natural graphite oxide from synthetic and natural graphite. The trend of electrical conductivity of both graphene (synthetic and natural) was compared with different graphite materials (synthetic, natural, and expanded) and carbon nanotubes (CNTs) under compression from 0.3 to 60 MPa. We found that synthetic graphene showed a marked increment in electrical conductivity compared to natural graphene. Interestingly, the total increment in electrical conductivity was greater for denser graphite; however, an opposite behavior was observed in nanocarbon materials such as graphene and CNTs, probably due to the differing layer arrangement of nanocarbon materials.

Correlation between signal pathway of chitosan and nitric oxide

  • Yoon, Hyun-Joong;Kim, Young-Ho;Park, Haeng-Soon
    • Proceedings of the PSK Conference
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    • 2003.04a
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    • pp.222.2-223
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    • 2003
  • Renal dipeptidase (RDPase, EC 3.4.13.19), an ectoenzyme of renal proximal tubules, is covalently bound to outer leaflet of lipid bilayer via glycosylphosphatidylinositol (GPI)-anchor. Chitin is a major component of the shells of crustacea such as crab, shrimp and crawfish. This study was conducted to examine the effect of chitosan on RDPase release from renal proximal tubules. Nitric oxide (NO), highly reactive free radical, inhibits the release of RDPase from porcine proximal tubules. (omitted)

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EPD Thick Film Formation of Ceramic Powder Materials (세라믹 분말재료의 EPD 후막형성 기술)

  • Soh, Dea-Wha;Jeon, Yong-Woo
    • Journal of the Speleological Society of Korea
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    • no.75
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    • pp.49-54
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    • 2006
  • Electrophoretic Deposition (EPD) is the most convenient technology to deposit natural or oxide powders of nonconductive materials in alcoholic suspension solution with adding electrolyte of iodine to form ceramic thick film on metal substrate under applied electric field with double electric layer between electrode and metal substrate. In this research work, the important parameters and technical ways were studied to form EPD thick films of typical oxide ceramics of Al2O3, YBCO and tourmaline powders.