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Liquid-phase dehydration of d-xylose over silica–alumina catalysts with different alumina contents
You, S. J.,Kim, Y. T.,Park, E. D. Springer Science and Business Media 2014 Reaction kinetics, mechanisms and catalysis Vol.111 No.2
The dehydration of d-xylose into furfural was examined using SiO2-Al2O3 catalysts with varying alumina contents to determine the effects of surface acidity on the catalytic performance. For comparison, SiO2 and Al2O3 catalysts were also examined. d-Xylose conversion increased with increasing alumina content in the SiO2-Al2O3 catalysts. Conversely, furfural selectivity at a similar d-xylose conversion decreased with increasing alumina content in the SiO2-Al2O3 catalyst. Lewis acid sites appeared to catalyze the isomerization of d-xylose into lyxose and xylulose, decomposition of d-xylose into C-1-C-3 products, and polymerization of d-xylose and furfural into humin.
류정호(J.H.YOU),정일록(I.R. CHUNG),엄명도(M.D.EOM),김종춘(J.C.KIM),신영조(Y.J.SHIN),임철수(C.S.LIM),이호영(H.Y.LEE) 한국자동차공학회 1997 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1997 No.11_1
The effects of sulfur content of diesel fuel on oxidation catalyst were investigated using from 0.2 weight % to 0.05 weight % sulfur content fuel on engine dynamometer and the characteristics of the emission reduction were tested using the prepared catalyst at various operating conditions such as T-6 mode with and without Pt/V and Pt catalysts in the exhaust system.<br/> In addition. the prepared catalytic converter was installed to a heavy-duty diesel engine and light-duty diesel vehicle. Then the emission reduction performance of Pt/V and Pt catalyst was also compared with each regulation test mode such as D-13 CVS-75 mode<br/> The emission reduction performance of Pt catalyst with respect to CO, HC, SOF and aldehyde was found to be a little bit higher than that of Pt/V catalyst, but Pt catalyst showed the innate disadvantage of causing the increase of PM due to the sulfate formation via high SO₂ conversion at high exhaust temperature especially above 500℃ in heavy-duty diesel engine.<br/> In the D-13 mode, PM reduction efficiency of Pt catalyst equipped heavy-duty diesel engine is lower than that of Pt/V catalyst caused by increasing sulfate in the high exhaust temperature but in the CVS-75 mode. Pt catalyst equipped light-duty vehicle showed higher PM reduction efficiency than that of Pt/V catalyst.<br/>
Effects of dealumination and desilication of H-ZSM-5 on xylose dehydration
You, S.J.,Park, E.D. Elsevier 2014 Microporous and mesoporous materials Vol.186 No.-
The continuous liquid-phase dehydration of d-xylose into furfural was examined over various zeolites (H-ferrierite, H-ZSM-5, H-mordenite, H-β, and H-Y) having a similar surface area, external surface area, and amount of acid sites to determine the effects of zeolite structure on catalytic performance. Xylose conversion was proportional to the zeolite channel size, whereas the H-ZSM-5 zeolite showed the highest furfural selectivity due to shape-selectivity. In order to improve the catalytic activity, H-ZSM-5 zeolite was dealuminated or desilicated using an aqueous solution of HCl or NaOH, respectively. The prepared catalysts were characterized using N<SUB>2</SUB> physisorption, X-ray diffraction (XRD), solid-state <SUP>27</SUP>Al and <SUP>29</SUP>Si magic-angle spinning nuclear magnetic resonance (MAS/NMR) spectroscopy, temperature-programmed desorption of ammonia (NH<SUB>3</SUB>-TPD) and isopropylamine (IPA-TPD). Dealumination of H-ZSM-5 appeared to remove extra-framework Al species without a collapse of the crystalline zeolite framework, while desilication generated extra-framework Al species accompanied by destruction of the zeolite framework. Among the tested catalysts, dealuminated H-ZSM-5 showed the highest furfural selectivity.
You, M.S.,Lim, C.S.,Kwon, D.H.,Heo, J.H.,Im, S.H.,Chae, K.J. Elsevier Science 2015 ORGANIC ELECTRONICS Vol.21 No.-
Pure Sb<SUB>2</SUB>S<SUB>3</SUB> without oxide impurities was formed by thermal decomposition of Sb(thioacetamide: TA)<SUB>2</SUB>Cl<SUB>3</SUB> precursor. From the analysis of thermal properties of Sb(TA)<SUB>2</SUB>Cl<SUB>3</SUB>, we developed a spin-coating and heat-treatment process to form pure Sb<SUB>2</SUB>S<SUB>3</SUB> thin-films with controllable thickness due to the formation of insoluble Sb<SUB>2</SUB>S<SUB>3</SUB> by heat-treatment. Through the spin-coating and heat-treatment process, we could fabricate oxide-free Sb<SUB>2</SUB>S<SUB>3</SUB> planar type sensitized solar cell with 8.12mA/cm<SUP>2</SUP> of short circuit current density (J<SUB>sc</SUB>), 0.616V of open circuit voltage (V<SUB>oc</SUB>), 45.9% of fill factor (F.F), and overall power conversion efficiency (η) of 2.3% at 1 sun condition.
Choi, I.T.,You, B.S.,Eom, Y.K.,Ju, M.J.,Choi, W.S.,Kang, S.H.,Kang, M.S.,Seo, K.D.,Hong, J.Y.,Song, S.H.,Yang, J.W.,Kim, H.K. Elsevier Science 2014 ORGANIC ELECTRONICS Vol.15 No.11
Triarylamine-based dual-function coadsorbents containing a carboxylic acid acceptor linked by extended π-conjugation aryl linkers (e.g., phenylene: HC-A3, naphthalene: HC-A4 and anthracene: HC-A5) were newly designed and synthesized. They were used as coadsorbents in organic dye-sensitized solar cells (DSSCs) based on a porphyrin dye (hexyloxy-biphenyl-ZnP-CN-COOH (HOP)). For comparison, the π-conjugated phenyl linker (HC-A3) previously developed by our group was also used as a coadsorbent. The structural effects on the photophysical and electrochemical properties and DSSC performance were systematically investigated. As a result, the DSSCs based on HC-A4 and HC-5 displayed power conversion efficiencies (PCEs) of 8.2% and 5.1%, respectively, while the HC-A3-based DSSC achieved a PCE of 7.7%. In the case of HC-A4, both the short-circuit photocurrent densities (J<SUB>sc</SUB>) and open-circuit voltages (V<SUB>oc</SUB>) of DSSCs were simultaneously improved to a large extent due to the more effective prevention of π-π stacking of organic dye molecules and the better light-harvesting effect at short wavelengths. The HC-A5-based DSSC exhibited a much lower short-circuit current (J<SUB>sc</SUB>) and open-circuit voltages (V<SUB>oc</SUB>) compared to the HC-A4-based DSSC, due to the fact that the dihedral angle of the π-conjugated linkers was too high for electron injection into the TiO<SUB>2</SUB> conduction band (CB) level. This had a reduced effect on preventing the π-π stacking of dye molecules, resulting in lower J<SUB>sc</SUB> and V<SUB>oc</SUB> values.
An, B.K.,Cho, B.L.,You, S.J.,Paik, H.D.,Chang, H.I.,Kim, S.W.,Yun, C.W.,Kang, C.W. Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.7
A study was conducted to evaluate the effects of dietary yeast derived ${\beta}$-glucan and single-strain probiotics on the growth performance and antibody response in broiler chicks. Six hundred and thirty 1-d-old male broiler chicks were divided into seven groups, placed into three pens per group (30 birds per pen) and fed one of seven non-medicated corn-SBM based experimental diets containing 0.025, 0.05 or 0.1% Saccharomyces cerevisiae ${\beta}$-glucan and 0.05, 0.1 or 0.2% Bacillus amyloliquefaciens (BA-pro, $1.3{\times}10^9/g$) or devoid of them for 5 wk. The body weight gains in groups fed diets containing 0.025 or 0.1% ${\beta}$-glucan, 0.1% or 0.2% BA-pro were significantly higher (p<0.05) than the control over 1-35 d. Feed conversion rates of groups fed ${\beta}$-glucan and BA-pro tended to be improved compared to the control group. There were no significant differences in the relative weights of liver, abdominal fat and breast muscle. No significant differences were observed in the activities of serum enzymes and concentrations of various cholesterol fractions. The antibody titers against Newcastle disease or infectious bronchitis virus in the chicks fed diets containing ${\beta}$-glucan and BA-pro were significantly higher (p<0.05) than in the control. The concentrations of cecal lactic acid bacteria in all groups fed BA-pro were significantly increased (p<0.05) compared to the control. These results indicated that dietary yeast derived ${\beta}$-glucan and BA-pro exerted growth-promoting and immune-enhancing effects in broiler chickens. In addition, BA-pro added to the diets modulated the profiles of cecal microflora, reflecting a potential to be beneficial microorganisms in chickens.
Fernando, I.P. Shanura,Jayawardena, Thilina U.,Kim, Hyun-Soo,Lee, Won Woo,Vaas, A.P.J.P.,De Silva, H.I.C.,Abayaweera, G.S.,Nanayakkara, C.M.,Abeytunga, D.T.U.,Lee, Dae-Sung,Jeon, You-Jin Academic Press 2019 Environmental research Vol.172 No.-
<P><B>Abstract</B></P> <P>Particulate matter (PM) air pollution has gradually become a widespread problem in East Asia. PM may cause unfamiliar inflammatory responses, oxidative stress, and pulmonary tissue damage, and a comprehensive understanding of the underlying mechanisms is required in order to develop effective anti-inflammatory agents. In this study, fine dust collected from Beijing, China (CPM) (size < PM13 with majority < PM2.5) was evaluated for its oxidative stress- and inflammation-inducing effects, which cause cell damage, in A459 human lung epithelial cells. Oxidative stress was marked by an increase in intracellular ROS levels and the production of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and heme oxygenase-1 (HO-1). Upon induction of oxidative stress, a marked increase was observed in the expression of key inflammatory mediators such as COX-2 and PGE<SUB>2</SUB> and the pro-inflammatory cytokines TNF-α and IL-6 via NF-kB and MAPK pathways. Cellular damage was marked by a reduction in viability, increased lactate dehydrogenase (LDH) release, formation of apoptotic and necrotic bodies, accumulation of sub-G1 phase cells, and DNA damage. Apoptosis was found to be mediated via the activation of caspases through the mitochondria-mediated pathway. Fucosterol, purified from the brown alga <I>Sargassum binderi</I> (Sonder ex J. Agardh) by bio-assay-guided fractionation and purification, exhibited potential therapeutic effects against CPM-induced detrimental effects. Further studies could focus on developing fucosterol, in forms such as steroidal inhalers, against PM-induced pulmonary tissue inflammation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Fine dust air pollution is a major reason of pulmonary complications in East Asia. </LI> <LI> Dust particles induce oxidative stress and inflammation damaging the lung epithelial cells. </LI> <LI> Fucosterol suppressed the dust induced cell damage by inhibiting oxidative stress and inflammation. </LI> <LI> Fucosterol may have beneficial effects in alleviating adverse respiratory effects of air pollution. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
You, D.S.,Kim, C.S.,Kang, Y.J.,Lim, K.,Jung, S.,Kim, D.G.,Kim, J.K.,Jo, S.,Kim, J.H.,Kang, J.W. Elsevier 2012 CURRENT APPLIED PHYSICS Vol.12 No.3
We report on the fabrication of efficient annealing-free organic solar cells using co-solvent solution considered as a promising method for low-cost and time-saving manufacturing. Higher device efficiency could be obtained compared to the pure solvent casted device, resulting from the improved crystallinity, optical absorption and transport properties. The power conversion efficiency of 2.8% was obtained, demonstrating the feasibility of achieving low-cost and high-efficiency organic solar cells without any additional treatment and processing additives.