Mesoporous sulfur-modified iron oxide as an effective Fenton-like catalyst for degradation of bisphenol A

Du, J.,Bao, J.,Fu, X.,Lu, C.,Kim, S.H. Elsevier 2016 Applied Catalysis B Vol.184 No.-

<P>A mesoporous sulfur-modified iron oxide (MS-Fe) was prepared as a heterogeneous H2O2 catalyst for degradation of BPA. The physico-chemical properties of MS-Fe and bare M-Fe were characterized by BET surface area measurement, SEM, XRD, MIR and XPS. Both M-Fe and MS-Fe composites appeared as cubic microparticles with abundant pores and cracks as well as large surface area. As depicted by XRD, EDX and XPS, M-Fe is mainly consisted of hematite while MS-Fe is a kind of S-doped iron oxide with about 5-6% of sulfur element in terms of atomic ratio. In contrast to the poor catalytic activity of bare M-Fe, the MS Fe composites showed greatly improved efficiencies for H2O2 activation for BPA degradation. The high catalytic activity of this new Fenton-like catalyst can be obtained at different initial pH in range of 3.0-9.0. The time evolution of degradation of BPA followed pseudo-first-order kinetics, and the first-order rate constants showed a linear relationship with parameters of initial pH, catalyst dosage and concentration of BPA. However, the H2O2 dosage showed a dual effect on BPA degradation because excessive H2O2 addition lead to scavenging of hydroxyl radicals ((OH)-O-center dot). The investigation of working mechanisms of MS Fe suggested a synergistic effect of homogeneous and heterogeneous degradation reaction, wherein a strong acidic environment, abundant surface-bonded hydroxyl group and electron-mediating effect of sulfur all contributed to fast activation of H2O2. Overall, this new material overcomes the limitation of narrow working pH range and shows a fast oxidation of BPA with a low H2O2 and catalyst dosage, would have a good potential for environmental application. (C) 2015 Elsevier B.V. All rights reserved.</P>

China Spallation Neutron Source: Accelerator Design Iterations and R&D Status

J. Wei,C.-D. Deng,C.-H. Wang,C.-T. Shi,H. Sun,H.-F. Ouyang,H.-M. Qu,H.-Y. Dong,J. Li,J. Zhang,J.-S. Cao,J.-Y. Tang,L. Dong,L.-L. Wang,Q. Qin,Q.-B. Wang,S. Wang,S.-N. Fu,S.-X Fang,T. -G. Xu,W. Kang,Y.- 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.50 No.I

The China Spallation Neutron Source (CSNS) is a high-power, accelerator-based project currently under preparation. The accelerator complex consists of an H$^-$ ion source, an H$^-$ linac, a rapid-cycling proton synchrotron, and the transport lines. During the past year, the design of most accelerator systems went through major iterations, and initial research and developments was started on the prototyping of several key components.

Multi-objective optimization using evolutionary algorithm for axial flow pump impeller

H.S. Park,Fu-qing Miao (사)한국CDE학회 2013 한국CAD/CAM학회 국제학술발표 논문집 Vol.2010 No.8

Evolutionary algorithms (EA) are a unique and attractive approach to the real world multiobjective optimization design such as a axial flow pump impeller optimization design problem. In this paper, multi-objective evolutionary algorithm to the axial flow pump impeller optimization design is presented. In axial flow pump design process, in order to get high performance pump, designers usually try to increase the efficiency (η) and decrease the required NPSH (NPSHr) simultaneously. In this paper, multi-objective optimization of axial flow pump based on modified evolutionary algorithm Particle Swarm Optimization (MPSO) is performed. At first, the NPSHr and η in a set of axial flow pump are numerically investigated using commercial software ANSYS with the design variables concerning hub angle βh, chord angle βc, cascade solidity of chord σc, maximum thickness of blade H. And then, using the Group Method of Data Handling (GMDH) type neural networks in commercial software DTREG, the corresponding polynomial representation for NPSHr and η with respect to design variables are obtained. Finally, multi objective optimization based on modified Particle Swarm Optimization (MPSO) approach is used for Pareto based optimization. The result shows that an optimal solution of the axial flow pump impeller was obtained: NPSHr was decreased by 11.68% and efficiency was increased by 4.24% simultaneously. It means this optimization is feasible.

Environmentally friendly and non-polluting solvent pretreatment of palm samples for polyphenol analysis using choline chloride deep eutectic solvents

Fu, N.,Lv, R.,Guo, Z.,Guo, Y.,You, X.,Tang, B.,Han, D.,Yan, H.,Row, K.H. Elsevier 2017 Journal of chromatography Vol.1492 No.-

<P>In this work, choline chloride (ChCI) deep eutectic solvents (DESs) were evaluated for the pretreatment of palm samples in the analysis of polyphenols, such as protocatechuic acid, catechins, epicatechin, and caffeic acid. During the enrichment step of the pretreatment, eight DESs comprising ChCI with ethylene glycol (EG), glycerol (Gly), xylitol (Xyl), phenol (Ph), formic acid (FA), citric acid (CiA), oxalic acid (OA), or malonic acid (MA), were prepared and applied to the reflux extraction of polyphenols from palm samples. All the DESs exhibited higher polyphenol extraction efficiency than methanol, and the highest extraction efficiency was obtained using ChCI-FA (1:1, mole ratio). For the purification step of the pretreatment, eight ChCI DES-modified adsorbents were prepared by hydrothermal polymerization and packed into solid phase extraction (SPE) cartridges, and ChCI-Urea, ChCI-Gly, ChCI-FA, and water, were used as eluents. The ChCI DES-modified adsorbents were characterized by Fourier transform infrared spectroscopy, thermal gravimetric analysis, scanning electron microscopy, and Brunauer-Emmett-Teller surface analysis, and the polyphenols were analyzed by mass spectrometry and high-performance liquid chromatographultraviolet detection. The highest purification efficiency was obtained using the ChCI-Ph DES-modified adsorbent as the SPE packing material and ChCI-Urea-H2O (1:1:5, mole ratio), ChCI-Gly (1:1, mole ratio), ChCI-FA-H2O (1:1:5, mole ratio), and H2O as the eluents. Compared to conventional purification processes that employ commercial C-18 or C-8 SPE columns with organic solvents as eluents, the ChCI DES-based SPE purification process successfully avoided the use of expensive commercial SPE columns and organic solvents. Furthermore, it isolated a larger amount of the target compounds under the same experimental conditions, and could be applied over five cycles with good reversibility. This work indicates that DESs as green solvents have great potential for the totally green pretreatment of samples during the enrichment and purification processes. (C) 2017 Elsevier B.V. All rights reserved.</P>

TRANSPORT OF SOLAR WIND H ⁺ AND He ⁺⁺ IONS ACROSS EARTH’S BOW SHOCK

Parks, G. K.,Lee, E.,Fu, S. Y.,Kim, H. E.,Ma, Y. Q.,Yang, Z. W.,Liu, Y.,Lin, N.,Hong, J.,Canu, P.,Dandouras, I.,Rè,me, H.,Goldstein, M. L. American Astronomical Society 2016 ASTROPHYSICAL JOURNAL LETTERS - Vol.825 No.2

<P>We have investigated the dependence of mass, energy, and charge of solar wind ( SW) transport across Earth's bow shock. An examination of 111 crossings during quiet SW in both quasi-perpendicular and quasi-parallel shock regions shows that 64 crossings had various degrees of heating and thermalization of SW. We found 22 crossings where the SW speed was <400 km s(-1). The shock potential of a typical supercritical quasi-perpendicular shock estimated from deceleration of the SW and cutoff energy of electron flat top distribution is similar to 50 Volts. We find that the temperatures of H+ and He++ beams that penetrate the shock can sometimes be nearly the same in the upstream and downstream regions, indicating little or no heating had occurred crossing the bow shock. None of the models predict that the SW can cross the bow shock without heating. Our observations are important constraints for new models of collisionless shocks.</P>

Oxidation as A Means to Remove Surface Contaminants on Cu Foil Prior to Graphene Growth by Chemical Vapor Deposition

Pang, Jinbo,Bachmatiuk, Alicja,Fu, Lei,Yan, Chenglin,Zeng, Mengqi,Wang, Jiao,Trzebicka, Barbara,Gemming, Thomas,Eckert, Juergen,Rummeli, Mark H. American Chemical Society 2015 The Journal of Physical Chemistry Part C Vol.119 No.23

<P>One of the more common routes to fabricate graphene is by chemical vapor deposition (CVD). This is primarily because of its potential to scale up the process and produce large area graphene. For the synthesis of large area monolayer Cu is probably the most popular substrate since it has a low carbon solubility enabling homogeneous single-layer sheets of graphene to form. This process requires a very clean substrate. In this work we look at the efficiency of common pretreatments such as etching or wiping with solvents and compare them to an oxidation treatment at 1025 °C followed by a reducing process by annealing in H<SUB>2</SUB>. The oxidation/reduction process is shown to be far more efficient allowing large area homogeneous single layer graphene formation without the presence of additional graphene flakes which form from organic contamination on the Cu surface.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2015/jpccck.2015.119.issue-23/acs.jpcc.5b03911/production/images/medium/jp-2015-03911k_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp5b03911'>ACS Electronic Supporting Info</A></P>

Synthesis and spectral properties of nanocrystalline Eu³⁺-doped pyrochlore oxide M₂Sn₂O₇ (M = Gd and Y)

Fu, Z.,Gong, W.,Li, H.,Wu, Q.,Li, W.,Yang, H.K.,Jeong, J.H. Elsevier 2011 Current Applied Physics Vol.11 No.3

Nanocrystalline Eu<SUP>3+</SUP>-doped pyrochlore oxide M<SUB>2</SUB>Sn<SUB>2</SUB>O<SUB>7</SUB> (M = Gd and Y) has been successfully prepared by a simple and facile hydrothermal synthesis method without the presence of catalysts. The effects of hydrothermal temperature, time and base concentration on the pure phase of the products are investigated. It is found that tuning the base concentration was a crucial step for the control of the pure phase of the M<SUB>2</SUB>Sn<SUB>2</SUB>O<SUB>7</SUB> (M = Gd and Y) nanocrystals. All the products were systematically characterized by powder X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier-Transform Infrared Spectroscopy (FT-IR), photoluminescence (PL) and photoluminescent excitation spectra (PLE). Furthermore, the luminescence mechanism and size dependence of their spectral properties are also discussed in detail.

Ordering and Magnetic Properties of Post-annealed CoPt and CoPt/Au Thin Films

Fu-Te Yuan,H. W. Huang,H. W. Chang,A. C. Sun,J. H. Hsu,H. Y. Lee,S. K. Chen 한국자기학회 2008 한국자기학회 학술연구발표회 논문개요집 Vol.- No.-

Photoluminescence Properties and Spectral Structure Analysis of NaLn(MoO₄)₂:Eu³⁺ (Ln = Gd, Y) Phosphors

Fu, Z.,Wang, X.,Sheng, T.,Fu, X.,Jeong, J.H. American Scientific Publishers 2014 Journal of Nanoscience and Nanotechnology Vol.14 No.5

In this paper, a facile synthetic route for the preparation of NaLn(MoO4)(2):Eu3+ (Ln = Gd, Y) nanocrystals by a hydrothermal method is reported. The NaLn(MoO4)(2):Eu3+ (Ln = Gd, Y) micro-powders were synthesized by a high temperature solid-state reaction. The optical properties of Eu3+ as a local structural probe are analyzed when being incorporated into NaLn(MoO4)(2) (Ln = Gd, Y) micro- powders and nanocrystals. In NaLn(MoO4)(2):Eu3+ (Ln = Gd, Y), the substitution of Ln(3+) by Eu3+ is confirmed and the point symmetry of the site and crystal structure are analyzed. The luminescence mechanism and the size dependence of their fluorescence properties in NaLn(MoO4)(2):Eu3+ (Ln = Gd, Y) micro-powders and nanocrystals are also discussed in detail.

Hydrothermal synthesis and optical characteristics of Eu³⁺ in Zn₂SnO₄ nanocrystals

Fu, Z.,Yang, H.K.,Moon, B.K.,Choi, B.C.,Jeong, J.H. Elsevier 2009 Current Applied Physics Vol.9 No.6

Zn<SUB>2</SUB>SnO<SUB>4</SUB>:Eu<SUP>3+</SUP> nanocrystals were one-step synthesized by hydrothermal method for the first time. All the products were systematically characterized by powder X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), electron probe X-ray microanalyzer (EPMA), photoluminescence (PL) and photoluminescent excitation (PLE). The characteristic peak of Eu<SUP>3+</SUP>-doped in Zn<SUB>2</SUB>SnO<SUB>4</SUB> nanocrystals was also detected. The luminescent properties of blank and Eu<SUP>3+</SUP>-doped Zn<SUB>2</SUB>SnO<SUB>4</SUB> nanocrystals were reported.