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The Influence of a Second Metal on the Ni/SiC Catalyst for the Methanation of Syngas
( Lan Lan Song ),( Yue Yu ),( Xiao Xiao Wang ),( Guoq Jang Jin ),( Ying Yong Wang ),( Xiang Yun Guo ) 한국화학공학회 2014 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.52 No.5
The catalytic performance of silicon carbide supported nickel catalysts modified with or without secondmetal (Co, Cu and Zn) for the methanation of CO has been investigated in a fixed-bed reactor using a feed consisting of25% CO and 75% H2 without any diluent gas. It has been found that the introduction of Co species can clearly improvethe catalytic activity of Ni/SiC catalyst, whereas the addition of Cu or Zn can result in a significant decrease in the catalyticactivity. The characterizations by means of XRD, TEM, XPS, CO-TPD and H2-TPR indicate that the addition ofCo could decrease the particle size of active metal, increase active sites on the surface of methanation catalyst, improvethe chemisorption of CO and enhance the reducibility of methanation catalysts. Additionally, the special interaction betweenCo species and Ni species is likely favorable for the dissociation of adsorbed CO on the surface of catalyst, and this mayalso contribute to the high activity of 5Co-Ni/SiC catalyst for CO methanation reaction. For 5Cu-Ni/SiC catalyst and 5Zn-Ni/SiC catalyst, Cu and Zn species could cover partial nickel particles and decrease the chemisorption amount of CO. These could be responsible for the low methanation activity. In addition, a 150h stability test under 2 MPa and 300 oCshowed that 5Co-Ni/SiC catalyst was very stable for CO methanation reaction.
Wang, Lan,Wang, Li,Li, Xiaojuan,Wang, Linsong,Roh, Kwang-Soo,Wang, Myeong-Hyeon The Korean Society for Applied Biological Chemistr 2009 Applied Biological Chemistry (Appl Biol Chem) Vol.52 No.2
Light and temperature variations are important during the vegetative stage of the Chinese red radish. We found that peroxidase (POD) and catalase activities and the content of pelargonidin were decreased by treatments of short of light perioid and low temperatures, while the content of hydrogen peroxide was increased. The POD isoenzymes of the radish organs were detected diversely depending on the developmental stages by polyacrylamide gel electrophoresis analysis; semi-quantitative RT-PCR revealed that expression was significantly induced during the flourishing anthesis stage in the bud. These results suggest that POD expression is both time-dependent and tissue-specific and that light and temperature conditions can influence the growth and antioxidant activity of the radish.
Lan Wang,Ming Lu Xu,Jie Liu,You Wang,Jian He Hu,Myeong-Hyeon Wang 한국영양학회 2015 Nutrition Research and Practice Vol.9 No.6
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-α, and the anti-inflammatory cytokines IL-1β 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.
Lan Wang,노광수,Li Wang,Xiaojuan Li,Linsong Wang,왕명현 한국응용생명화학회 2009 Journal of Applied Biological Chemistry (J. Appl. Vol.52 No.2
Light and temperature variations are important during the vegetative stage of the Chinese red radish. We found that peroxidase (POD) and catalase activities and the content of pelargonidin were decreased by treatments of short of light perioid and low temperatures, while the content of hydrogen peroxide was increased. The POD isoenzymes of the radish organs were detected diversely depending on the developmental stages by polyacrylamide gel electrophoresis analysis; semi-quantitative RT-PCR revealed that expression was significantly induced during the flourishing anthesis stage in the bud. These results suggest that POD expression is both timedependent and tissue-specific and that light and temperature conditions can influence the growth and antioxidant activity of the radish.
Lan Yao,Zhen Wang,Qingbiao Wang,Jianwei Xia,Hao Shen 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.7
In this paper, the exponential stabilization of delayed complex-valued neural networks (DCNNs) is addressed via sampled-data control. First, aperiodic sampled-data control aimed at further reducing the frequency of data transmission is adopted, which covers the periodic sampling as a special case. Then, a free-matrix-based timedependent Lyapunov functional is specially constructed for stability analysis of closed-loop DCNNs, in which two extra free matrices are introduced and the available information of system states at the sampling instants are fullyutilized. Accordingly, some less conservative stability conditions are established. By resorting to a matrix transformation, the design scheme for the feedback gains can be obtained. Meanwhile, the qualitative relationship between the decay rate and the upper bound of the variable sampling period is established and the maximum allowable value of the variable sampling period is determined. Finally, an illustrative example is provided to demonstrate the feasibility of the proposed stabilization criteria.
Acetone-butanol-ethanol Fermentation and Isoflavone Extraction Using Kudzu Roots
Lan Wang,Hongzhang Chen 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.4
The economics of Acetone-butanol-ethanol (ABE) fermentation is greatly affected by raw materials,and the use of readily available starchy materials from marginal farming lands could be a viable option for reducing costs. Kudzu, a rapidly growing perennial leguminous vine, has been planted on marginal farming land and widely distributed in Asia and America. This study investigated ABE fermentation by C. acetobutylicum ATCC 824 using kudzu roots and isoflavone extraction from kudzu fermentation residue (KFR). The kudzu roots could be used as a sole substrate for ABE fermentation without nutritional supplements. Batch culture containing 140 g kudzu/L produced 17.99 ± 1.08 g/L solvent (ABE), including 11.20± 0.79 g/L butanol, 5.54 ± 0.20 g/L acetone, and 1.15 ±0.09 g/L ethanol, with a productivity of 0.19 g/(L/h) and a yield of 0.33 g solvent/g sugar after 96 h of fermentation. Isoflavone yield extracted from KFR was 1.90/100 g KFR,approximately 48% higher compared with that extracted from raw kudzu. A kinetic analysis of the extraction process showed that both the isoflavone yield and the extraction rate obtained from KFR were higher than the corresponding values obtained from raw kudzu. These results indicate that kudzu may provide a new potential raw material for ABE production and the process of ABE fermentation integrated with isoflavone extraction may provide a new way to reduce fermentable substrate costs.