Preparation of titania-containing photocatalysts from metallurgical slag waste and photodegradation of 2,4-dichlorophenol

Hong Liu,S Vigneswaran,Tao Xia,H.K. Shon 한국공업화학회 2011 Journal of Industrial and Engineering Chemistry Vol.17 No.3

A low cost, high performance titania-containing metallurgical slag photocatalysts (TCMSPx, x = H2SO4,HNO3, HCl) were prepared using a hydrothermal method. The prepared TCMSPx were characterized in terms of visual, physical and chemical properties. The photocatalytic activity of the TCMSPx was evaluated via the photodegradation of 2,4-dichlorophenol (2,4-D) in aqueous solution. The results showed that the characteristics and photocatalytic activity of TCMSPx were strongly affected by acidic solutions used during the acidolysis. TCMSPH2SO4 exhibited better characteristics and higher photocatalytic activity than TCMSPHNO3 and TCMSPHCl. OH radicals from TCMSPH2SO4 were produced under UV, visible and solar light irradiation. The degree of photodegradation of 2,4-D by TCMSPH2SO4 was 80.1%, 50.0% and 61.5% under UV, visible and solar light irradiation respectively. In addition, the removal of chlorine functional group on the 2,4-D benzene ring and the production of intermediates during 2,4-D photodegradation were monitored using ion chromatography, UV–vis spectra and high performance liquid chromatography of 2,4-D before and after photodegradation.

Synthesis and characterization of ampelopsin glucosides using dextransucrase from Leuconostoc mesenteroides B-1299CB4: Glucosylation enhancing physicochemical properties

Woo, H.J.,Kang, H.K.,Nguyen, T.T.H.,Kim, G.E.,Kim, Y.M.,Park, J.S.,Kim, D.,Cha, J.,Moon, Y.H.,Nam, S.H.,Xia, Y.m.,Kimura, A.,Kim, D. IPC Science and Technology Press ; Elsevier Scienc 2012 Enzyme and microbial technology Vol.51 No.6

Novel ampelopsin glucosides (AMPLS-Gs) were enzymatically synthesized and purified using a Sephadex LH-20 column. Each structure of the purified AMPLS-Gs was determined by nuclear magnetic resonance, and the ionic product of AMPLS-G1 was observed at m/z 505 (C<SUB>21</SUB>H<SUB>22</SUB>O<SUB>13</SUB>.Na)<SUP>+</SUP> using matrix-assisted laser desorption ionization time-of-flight mass spectrometry. AMPLS-G1 was identified as ampelopsin-4'-O-α-d-glucopyranoside. The optimum condition for AMPLS-G1, determined using response surface methodology, was 70mM ampelopsin, 150mM sucrose, and 1U/mL dextransucrase, which resulted in an AMPLS-G1 yield of 34g/L. The purified AMPLS-G1 displayed 89-fold increased water solubility and 14.5-fold browning resistance compared to those of AMPLS and competitive inhibition against tyrosinase with a K<SUB>i</SUB> value of 40.16μM. This value was smaller than that of AMPLS (K<SUB>i</SUB>=62.56μM) and much smaller than that of β-arbutin (K<SUB>i</SUB>=514.84μM), a commercial active ingredient of whitening cosmetics. These results indicate the potential of AMPLS and AMPLS-G1 as superior ingredients for functional cosmetics.

Synthesis and biological evaluation of diverse tetrahydrobenzofuran-4-ones as potent antibacterial agents

Xia, L.,Idhayadhulla, A.,Lee, Y.R.,Kim, S.H.,Wee, Y.J. Korean Society of Industrial and Engineering Chemi 2015 Journal of industrial and engineering chemistry Vol.22 No.-

Diverse 3,5,6,7-tetrahydrobenzofuran-4-one derivatives (3a-3n) were synthesized in high yields by ruthenium complex or rhodium complex catalyzed [3+2] cycloaddition. The antibacterial activities of these 3,5,6,7-tetrahydrobenzofuran-4-ones were evaluated against Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Enterobacter aerogenes) and Gram-positive bacteria (Bacillus cereus and Staphylococcus aureus). In particular, compound 3b showed the highest antibacterial activity against P. aeruginosa and S. aureus (both MICs: 2μg/mL). Compound 3l, which has the 2H-pyrano[2,3-b]benzofuran skeleton, exhibited excellent inhibitory activity against B. cereus (MIC: 0.5μg/mL) as compared with ciprofloxacin (MIC: 2μg/mL) and ampicillin (MIC: 1μg/mL).

Dynamic interaction analysis of a LIM train and elevated bridge system

H. Xia,W. W. Guo,C. Y. Xia,Y.-L. Pi,M. A. Bradford 대한기계학회 2009 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.23 No.12

A three-dimensional dynamic interaction model is developed for a LIM (linear induction motor) train and elevated bridge system, which is composed of a LIM-driven vehicle submodel and a finite element bridge submodel. Each LIM vehicle is modeled by a 27 degrees-of-freedom dynamic system. The expressions for the electromagnetic force between the linear motor and the reaction plate are derived, and the force model is established. By applying a modal superposition technique to the bridge submodel and using the measured track irregularities as the self-excitations of the train-bridge system, the equations of motion are established for analyzing the dynamic responses of the LIM vehicle and the elevated bridge. The proposed framework is applied to a 3-span elevated bridge with 29.9 m simply-supported girders. The full histories of the LIM train traversing the bridge are simulated, from which the dynamic responses of the LIM vehicle and elevated bridge system are obtained. The proposed method may help to find a way to assess the dynamic properties of elevated bridges and the running safety of a LIM train with reasonable computational effort.

MODEL-BASED DESIGN OF A VARIABLE NOZZLE TURBOCHARGER CONTROLLER

H. G. ZHANG,E. H. WANG,B. Y. FAN,M. G. OUYANG,S. Z. XIA 한국자동차공학회 2011 International journal of automotive technology Vol.12 No.2

Variable Nozzle Turbocharger (VNT) was invented to solve the problem of matching an ordinary turbocharger with an engine. VNT can harness exhaust energy more efficiently, enhance intake airflow response and reduce engine emissions, especially during transient operating conditions. The difficulty of VNT control lies in how to regulate the position of the nozzle at different engine working conditions. The control strategy designed in this study is a combination of a closedloop feedback controller and an open-loop feed-forward controller. The gain-scheduled proportional-integral-derivative (PID)controller was implemented as the feedback controller to overcome the nonlinear characteristic. As it is difficult to tune the parameters of the gain-scheduled PID controller on an engine test bench, system identification was used to identify the plant model properties at different working points for a WP10 diesel engine on the test bench. The PID controller parameters were calculated based on the identified first-order-plus–dead-time (FOPDT) plant model. The joint simulation of the controller and the plant model was performed in Matlab/Simulink. The time-domain and frequency-domain performances of the entire system were evaluated. The designed VNT control system was verified with engine tests. The results indicated that the real boosting pressure traced the target boosting pressure well at different working conditions.

Effects of Copper-bearing Montmorillonite (Cu-MMT) on Escherichia coli and Diarrhea on Weanling Pigs

Xia, M.S.,Hu, C.H.,Xu, Z.R.,Ye, Y.,Zhou, Y.H.,Xiong, L. Asian Australasian Association of Animal Productio 2004 Animal Bioscience Vol.17 No.12

Copper-bearing montmorillonite (Cu-MMT) was produced by $Cu^{2+}$ cation exchange reaction. X-ray diffraction analysis showed that that the (001) basal spacing of the MMT crystal lattice increased from 1.544 to 1.588 nm after $Cu^{2+}$ exchange. This indicated that $Cu^{2+}$ entered into interlayer position of MMT as a hydrated cation or composite cation. In vitro results indicated that Cu-MMT had antibacterial activity on Escherichia coli $K_{88}$. Cu-MMT had unbalanced positive charge after cation exchange. Its antibacterial activity resulted from two aspects, one was electrostatic attraction which made E. coli $K_{88}$ being adhered on the montmorillonite surface, the other was the $Cu^{2+}$ slowly released, which could kill bacteria. In an in vivo study, four replicates of eight weanling pigs were assigned to each of two dietary treatments to study the effects of Cu-MMT on diarrhea, E. coli in the lumen of the jejunum and morphology of jejunal mucosa. As compared to the control, supplementation of the diet with 0.2% Cu-MMT improved average daily gain by 12.50% (p<0.05) and decreased F/G by 9.42% (p<0.05). The mean diarrhrea incidence was decreased by 71.80% (p<0.05). The viable counts of Escherichia coli in jejunal contents were significantly reduced (p<0.05). Villus height and the villus height to crypt depth ratio at the jejunal mucosa were increased by 19.09% (p<0.05) and 37.10% (p<0.05), respectively.

Seed-mediated synthesis of Pd-Rh bimetallic nanodendrites

Kobayashi, H.,Lim, B.,Wang, J.,Camargo, P.H.C.,Yu, T.,Kim, M.J.,Xia, Y. North Holland ; Elsevier Science Ltd 2010 Chemical physics letters Vol.494 No.4

This Letter describes a simple, aqueous-phase route to the synthesis of Pd-Rh bimetallic nanodendrites consisting of Rh branches anchored to a Pd nanocrystal core. Palladium nanocrystals with various shapes, including truncated octahedron, cube, octahedron, and thin plate, have all been successfully employed as seeds to grow Rh branches via the reduction of Na<SUB>3</SUB>RhCl<SUB>6</SUB> with l-ascorbic acid in an aqueous solution. The degree of Rh branching could be controlled by varying the concentration of Na<SUB>3</SUB>RhCl<SUB>6</SUB> involved in a synthesis. Electron microscopy analysis revealed that growth of Rh branches proceeded via attachment of small Rh particles that had been formed via homogeneous nucleation in solution.

DGCL: An Efficient Density and Grid Based Clustering Algorithm for Large Spatial Database

Kim, H. S.,Gao, S.,Xia, Y.,Kim, G. B.,Bae, H. Y. SPRINGER-VERLAG 2006 ICHIT 2012 Vol.4016 No.-

Decode-and-Forward Two-Path Half-Duplex Relaying: Diversity-Multiplexing Tradeoff Analysis

Wicaksana, H.,Ting, S. H.,Guan, Y. L.,Xia, X.-G IEEE 2011 IEEE TRANSACTIONS ON COMMUNICATIONS Vol.59 No.7

<P>Two-path or successive relaying has recently emerged as a promising cooperative communication protocol to improve spectral efficiency in half-duplex relaying networks. In this paper, we consider decode-and-forward (DF) version of the two-path relaying protocol. We analyze the fundamental performance of this protocol in terms of the diversity-multiplexing tradeoff (DMT). We first derive the DMT for this protocol, where perfect decoding at the relays is assumed, and show that it approaches the 3 x 1 multiple-input single-output (MISO) DMT. We then remove the assumption of perfect decoding at the relays and derive the closed-form expression of the achievable DMT based on the relative distances between nodes. Specifically, we found that for sufficiently long transmission length, if the average source-relay SNR is at least 2.5 times (measured in dB) of other links, the 3 x 1 MISO DMT is achieved. Successive interference cancellation at the relays is also proposed to further improve the performance of the DMT.</P>

Improved delay-dependent stability criteria for T-S fuzzy systems with time-varying delay

Zeng, H.B.,Park, J.H.,Xia, J.W.,Xiao, S.P. Elsevier [etc.] 2014 Applied Mathematics and Computation Vol.235 No.-

This paper is concerned with the robust stability of uncertain T-S fuzzy systems with time-varying delay. A novel Lyapunov-Krasovskii functional is established by employing the idea of combining delay-decomposition with state vector augmentation. Then, by employing some integral inequalities and the reciprocally convex approach, some less conservative delay-dependent stability criteria are obtained. The proposed stability conditions are formulated in the form of linear matrix inequalities (LMIs), which can be solved efficiently with Semi-Definite Programming (SDP) solvers. Finally, four numerical examples are provided to show that the proposed conditions are less conservative than existing ones.