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Sample records for sub-3 nm particle

  1. Sub-3 nm particles observed at the coastal and continental sites in the United States

    Science.gov (United States)

    Yu, Huan; Gannet Hallar, A.; You, Yi; Sedlacek, Arthur; Springston, Stephen; Kanawade, Vijay P.; Lee, Yin-Nan; Wang, Jian; Kuang, Chongai; McGraw, Robert L.; McCubbin, Ian; Mikkila, Jyri; Lee, Shan-Hu

    2014-01-01

    Direct measurements of atmospheric sub-3 nm particles are crucial for understanding the new particle formation mechanisms, but such measurements are very limited at present. We report measurements of sub-3nm particles at Brookhaven, New York (a coastal site in summer) and Kent, Ohio (a continental site in winter). During daytime, in approximately 80% of the observation days at both sites, sub-3nm particle events were observed with concentrations of 2800 ± 1600 cm-3, and they appeared with the elevated sulfuric acid concentrations. During the nighttime at the coastal site under the marine air mass influences, there were also substantial concentrations of sub-3nm particles (1500 ± 400 cm-3), but they did not grow larger. On the other hand, at the coastal Brookhaven site under the continental air mass influences and at the inland Kent site during the night, the sub-3nm particles were significantly lower (190 ± 130 cm-3). Our results indicate that sub-3nm particles were not always present, and their presence was rather closely associated with specific aerosol nucleation precursors: sulfuric acid and other unknown condensable chemical species likely present in the marine air masses. These findings are thus different from other studies conducted in the Finland boreal forest, which showed a persistent presence of high concentrations of sub-2nm particles and that these sub-2nm particles were more correlated to monoterpene oxidation products than to sulfuric acid. Therefore, different nucleation mechanisms, as opposed on to a universal mechanism, involving different nucleation precursors dominate in different atmospheric environments with different emissions and transported trace gases.

  2. Performance of diethylene glycol-based particle counters in the sub-3 nm size range

    CERN Document Server

    Wimmer, D; Franchin, A; Kangasluoma, J; Kreissl, F; Kürten, A; Kupc, A; Metzger, A; Mikkilä, J; Petäjä, J; Riccobono, F; Vanhanen, J; Kulmala, M; Curtius, J

    2013-01-01

    When studying new particle formation, the uncertainty in determining the "true" nucleation rate is considerably reduced when using condensation particle counters (CPCs) capable of measuring concentrations of aerosol particles at sizes close to or even at the critical cluster size (1–2 nm). Recently, CPCs able to reliably detect particles below 2 nm in size and even close to 1 nm became available. Using these instruments, the corrections needed for calculating nucleation rates are substantially reduced compared to scaling the observed formation rate to the nucleation rate at the critical cluster size. However, this improved instrumentation requires a careful characterization of their cut-off size and the shape of the detection efficiency curve because relatively small shifts in the cut-off size can translate into larger relative errors when measuring particles close to the cut-off size. Here we describe the development of two continuous-flow CPCs using diethylene glycol (DEG) as the working fluid. The desig...

  3. Nucleation and growth of sub-3 nm particles in the polluted urban atmosphere of a megacity in China

    Directory of Open Access Journals (Sweden)

    H. Yu

    2016-03-01

    Full Text Available Particle size distribution down to 1.4 nm was measured in the urban atmosphere of Nanjing, China, in spring, summer, and winter during 2014–2015. Sub-3 nm particle event, which is equivalent to nucleation event, occurred on 42 out of total 90 observation days, but new particles could grow to cloud condensation nuclei (CCN-active sizes on only 9 days. In summer, infrequent nucleation was limited by both unfavorable meteorological conditions (high temperature and relative humidity – RH and reduced anthropogenic precursor availability due to strict emission control measures during the 2014 Youth Olympic Games in Nanjing. The limiting factors for nucleation in winter and spring were meteorological conditions (radiation, temperature, and RH and condensation sink, but for the further growth of sub-3 nm particles to CCN-active sizes, anthropogenic precursors again became limiting factors. Nucleation events were strong in the polluted urban atmosphere. Initial J1.4 at the onset and peak J1.4 at the noontime could be up to 2.1 × 102 and 2.5 × 103 cm−3 s−1, respectively, during the eight nucleation events selected from different seasons. Time-dependent J1.4 usually showed good linear correlations with a sulfuric acid proxy for every single event (R2 = 0.56–0.86, excluding a day with significant nocturnal nucleation, but the correlation among all eight events deteriorated (R2 =  0.17 due to temperature or season change. We observed that new particle growth rate (GR did not increase monotonically with particle size, but had a local maximum up to 25 nm h−1 between 1 and 3 nm. The existence of local maxima GR in sub-3 nm size range, though sensitive to measurement uncertainties, gives new insight into cluster dynamics in polluted environments. In this study such growth rate behavior was interpreted as the solvation effect of organic activating vapor in newly formed inorganic nuclei.

  4. Symmetric stretch excitation of CH/sub 3/ in the 193. 3 nm photolysis of CH/sub 3/I

    Energy Technology Data Exchange (ETDEWEB)

    Continetti, R.E.; Balko, B.A.; Lee, Y.T.

    1988-09-01

    New high resolution photofragment translational spectroscopy measurements on the 193.3 nm photolysis of CH/sub 3/I reveal up to four quanta of ..nu../sub 1/ C--H symmetric stretch excitation in the C--I bond fission channel. In addition these experiments show for the first time that C--H bond fission occurs at wavelengths longer than 185 nm with a quantum yield of approx.3%. The data yields upper bounds to the C--H bond dissociation energy in CH/sub 3/I of 101 +- 1 kcal/mol and for the C--I bond energy, 55.0 +- 0.3 kcal/mol.

  5. Nanocrystalline oxide (Y{sub 2}O{sub 3}, Dy{sub 2}O{sub 3}, ZrO{sub 2}, NiO) coatings on BaTiO{sub 3} submicron particles by precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Bassano, Alessio [University of Genoa, Department of Chemical and Process Engineering (Italy); Buscaglia, Vincenzo, E-mail: v.buscaglia@ge.ieni.cnr.i [National Research Council, Institute for Energetics and Interphases (Italy); Sennour, Mohamed [Ecole des Mines de Paris, Centre des Materiaux (France); Buscaglia, Maria Teresa; Viviani, Massimo [National Research Council, Institute for Energetics and Interphases (Italy); Nanni, Paolo [University of Genoa, Department of Chemical and Process Engineering (Italy)

    2010-02-15

    Nanocoatings (5-20 nm) of different compounds on fine BaTiO{sub 3} particles were obtained by means of precipitation processes. Homogeneous and smooth shells of Y(OH)CO{sub 3} and Dy(OH)CO{sub 3} were grown from nitrate solutions in the presence of urea. An irregular coating consisting of zirconia nanoparticles was produced from zirconyl nitrate solution using ammonia as a precipitating agent after adsorption of a polymeric polyelectrolyte on the BaTiO{sub 3} surface. Composite particles with a peculiar morphology were obtained by inducing heterogeneous nucleation and growth of Ni(OH){sub 2} lamellae on the BaTiO{sub 3} surface. The different shells can be transformed in a nanocrystalline coating of the corresponding oxide (Y{sub 2}O{sub 3}, Dy{sub 2}O{sub 3}, ZrO{sub 2}, NiO) by calcination at moderate temperatures (400-700 {sup o}C). The overall results indicate that precipitation from solution represents a versatile process to grow a second-phase layer on the surface of BaTiO{sub 3} particles. This approach can be used as an alternative to mechanical wet mixing for controlled doping of ferroelectric materials and for the fabrication of composite materials with specific geometry of the two-phase assembly.

  6. Synthesis of magnetic Fe sub 3 O sub 4 particles covered with a modifiable phospholipid coat

    CERN Document Server

    Cuyper, M D; Lueken, H; Hodenius, M

    2003-01-01

    This work reports the synthesis of iron oxide cores by coprecipitation of Fe sup 2 sup + and Fe sup 3 sup + ions with NaHCO sub 3 or NH sub 3. Depending on the experimental conditions, particles of two different sizes (13 or 130 nm diameter) were produced. X-ray diffractometry revealed Fe sub 3 O sub 4 (magnetite) to be the main constituent. The smaller particles, which, in contrast to the larger ones, are superparamagnetic, were stabilized with a phospholipid bilayer consisting of a 9:1 molar ratio of dimyristoylphosphatidylcholine and dimyristoylphosphatidylglycerol, thereby creating so-called magnetoliposomes. In a subsequent step, poly(ethylene glycol)-(PEG-) derivatized dipalmitoylphosphatidylethanolamine was introduced into the lipid envelope by incubating the magnetoliposomes with pre-formed sonicated vesicles containing the PEGylated lipid. The mechanism by which lipid transfer occurred was determined from the kinetic profiles. The relevance of these observations to a wide range of biomedical applicat...

  7. Fabrication of BaTiO{sub 3}/Ni composite particles and their electro-magneto responsive properties

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yaping [Key Laboratory of Applied Surface and Colloid Chemistry (Shaanxi Normal University), Ministry of Education, Xi’an 710119 (China); School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi’an 710119 (China); Gao, Lingxiang, E-mail: gaolx@snnu.edu.cn [Key Laboratory of Applied Surface and Colloid Chemistry (Shaanxi Normal University), Ministry of Education, Xi’an 710119 (China); School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi’an 710119 (China); Wang, Lijuan [Key Laboratory of Applied Surface and Colloid Chemistry (Shaanxi Normal University), Ministry of Education, Xi’an 710119 (China); School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi’an 710119 (China); Xie, Zunyuan, E-mail: zyxie123@snnu.edu.cn [Key Laboratory of Applied Surface and Colloid Chemistry (Shaanxi Normal University), Ministry of Education, Xi’an 710119 (China); School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi’an 710119 (China); Gao, Meixiang [Yulin Vocational and Technical College, Yulin 719000 (China); Zhang, Weiqiang [Key Laboratory of Applied Surface and Colloid Chemistry (Shaanxi Normal University), Ministry of Education, Xi’an 710119 (China); School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi’an 710119 (China)

    2017-07-15

    Graphical abstract: The spherical BaTiO{sub 3}/Ni particles with excellent structure were made by one-step method through fixing the metal Ni(0) reduced by a specific reducing agent (N{sub 2}H{sub 4}·H{sub 2}O) on the surface of the BaTiO{sub 3} particles with grain diameter of ∼500 nm. BaTiO{sub 3}/Ni particle has double responses of electric and magnetic field simultaneously. Consequentially, coating magnetic metal on BT particle is proposed an effective method to prepare novel electro-magneto responsive particles and one basis of electro-magneto responsive elastomers. - Highlights: • The BaTiO{sub 3}/Ni composite particles were fabricated. • The content of Ni(0) in nickel sheath is 70.2%. • The BaTiO{sub 3}/Ni particles have double responses of electric and magnetic field. - Abstract: BaTiO{sub 3} (BT)/Ni composite particles were made by one-step method through agglomerating the metal Ni(0) nanoparticles reduced by a specific reducing agent (N{sub 2}H{sub 4}·H{sub 2}O) on the surface of BT sphere with diameter of ∼500 nm. The BT/Ni composite particles were characterized by the means of scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS). In BT/Ni particles, pure BT spherical particle was coated with Ni nanoparticles agglomerated on its surface. The average thickness of the Ni sheath was ∼30 nm and the content of Ni(0) and Ni (II) in the sheath were 70.2% and 29.8%, respectively. The responsive effects of BT/Ni particles filled in hydrogel elastomer were investigated by the viscoelastic properties. The results indicate that the BT/Ni particles exhibit electro and magneto coordinated responsive properties (E = 1 kV/mm, H = 0.1 T/mm), which is superior to BT particles with individual electro response.

  8. Homogeneous pinhole free 1 nm Al{sub 2}O{sub 3} tunnel barriers on graphene

    Energy Technology Data Exchange (ETDEWEB)

    Dlubak, B.; Martin, M.-B.; Deranlot, C.; Bouzehouane, K.; Fusil, S.; Mattana, R.; Petroff, F.; Anane, A.; Seneor, P.; Fert, A. [Unite Mixte de Physique CNRS/Thales, 91767 Palaiseau (France) and University of Paris-Sud, 91405 Orsay (France)

    2012-11-12

    We report on the topographical and electrical characterisations of 1 nm thick Al{sub 2}O{sub 3} dielectric films on graphene. The Al{sub 2}O{sub 3} is grown by sputtering a 0.6 nm Al layer on graphene and subsequentially oxidizing it in an O{sub 2} atmosphere. The Al{sub 2}O{sub 3} layer presents no pinholes and is homogeneous enough to act as a tunnel barrier. A resistance-area product in the mega-ohm micrometer-square range is found. Comparatively, the growth of Al{sub 2}O{sub 3} by evaporation does not lead to well-wetted films on graphene. Application of this high quality sputtered tunnel barrier to efficient spin injection in graphene is discussed.

  9. Particle size effect on Moessbauer parameters in {gamma}-Fe{sub 2}O{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Siddique, M., E-mail: siddique56@hotmail.co [Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan); Ahmed, E. [Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan); Butt, N.M. [Preston Institute of Science and Technology (PINSAT), Preston University, H-8/1, Islamabad (Pakistan)

    2010-09-15

    Nanoparticles of maghemite ({gamma}-Fe{sub 2}O{sub 3}) were synthesized by chemical co-precipitation method for different particle size ranges and Moessbauer spectroscopy was employed to see the particle size effect on the Moessbauer parameters, especially on the average internal magnetic field of the system. It was observed that the internal magnetic field increased with increase in particle size. The contribution of superparamagnetic component for all size ranges is almost equal, i.e. 10%, while the relaxed subspectrum contributes around 50% at all stages. The superparamagnetic component was a quadrupole doublet up to 40 nm and then it transformed into a singlet at larger particle sizes. This indicates that the electric field gradient vanishes for this particular Fe environment and has an ideal cubic symmetry.

  10. Photolysis of CH{sub 3}CHO at 248 nm: Evidence of triple fragmentation from primary quantum yield of CH{sub 3} and HCO radicals and H atoms

    Energy Technology Data Exchange (ETDEWEB)

    Morajkar, Pranay; Schoemaecker, Coralie; Fittschen, Christa, E-mail: christa.fittschen@univ-lille1.fr [Université Lille Nord de France, PhysicoChimie des Processus de Combustion et de l’Atmosphère – PC2A, UMR 8522, F-59650 Villeneuve d’Ascq (France); Bossolasco, Adriana [Université Lille Nord de France, PhysicoChimie des Processus de Combustion et de l’Atmosphère – PC2A, UMR 8522, F-59650 Villeneuve d’Ascq (France); INFIQC (CONICET), Departamento de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba (Argentina)

    2014-06-07

    Radical quantum yields have been measured following the 248 nm photolysis of acetaldehyde, CH{sub 3}CHO. HCO radical and H atom yields have been quantified by time resolved continuous wave Cavity Ring Down Spectroscopy in the near infrared following their conversion to HO{sub 2} radicals by reaction with O{sub 2}. The CH{sub 3} radical yield has been determined using the same technique following their conversion into CH{sub 3}O{sub 2}. Absolute yields have been deduced for HCO radicals and H atoms through fitting of time resolved HO{sub 2} profiles, obtained under various O{sub 2} concentrations, to a complex model, while the CH{sub 3} yield has been determined relative to the CH{sub 3} yield from 248 nm photolysis of CH{sub 3}I. Time resolved HO{sub 2} profiles under very low O{sub 2} concentrations suggest that another unknown HO{sub 2} forming reaction path exists in this reaction system besides the conversion of HCO radicals and H atoms by reaction with O{sub 2}. HO{sub 2} profiles can be well reproduced under a large range of experimental conditions with the following quantum yields: CH{sub 3}CHO + hν{sub 248nm} → CH{sub 3}CHO{sup *}, CH{sub 3}CHO{sup *} → CH{sub 3} + HCO ϕ{sub 1a} = 0.125 ± 0.03, CH{sub 3}CHO{sup *} → CH{sub 3} + H + CO ϕ{sub 1e} = 0.205 ± 0.04, CH{sub 3}CHO{sup *}→{sup o{sub 2}}CH{sub 3}CO + HO{sub 2} ϕ{sub 1f} = 0.07 ± 0.01. The CH{sub 3}O{sub 2} quantum yield has been determined in separate experiments as ϕ{sub CH{sub 3}} = 0.33 ± 0.03 and is in excellent agreement with the CH{sub 3} yields derived from the HO{sub 2} measurements considering that the triple fragmentation (R1e) is an important reaction path in the 248 nm photolysis of CH{sub 3}CHO. From arithmetic considerations taking into account the HO{sub 2} and CH{sub 3} measurements we deduce a remaining quantum yield for the molecular pathway: CH{sub 3}CHO{sup *} → CH{sub 4} + CO ϕ{sub 1b} = 0.6. All experiments can be

  11. Investigations of mussel-inspired polydopamine deposition on WC and Al{sub 2}O{sub 3} particles: The influence of particle size and material

    Energy Technology Data Exchange (ETDEWEB)

    Mondin, Giovanni, E-mail: giovanni.mondin@chemie.tu-dresden.de [Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, 01069 Dresden (Germany); Haft, Marcel, E-mail: m.haft@ifw-dresden.de [Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Institute for Solid State Research, Helmholtzstr. 20, 01069 Dresden (Germany); Wisser, Florian M., E-mail: florian.wisser@chemie.tu-dresden.de [Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, 01069 Dresden (Germany); Leifert, Annika, E-mail: annika.leifert@chemie.tu-dresden.de [Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, 01069 Dresden (Germany); Mohamed-Noriega, Nasser, E-mail: nasser.mohamed-noriega@chemie.tu-dresden.de [Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, 01069 Dresden (Germany); Dörfler, Susanne, E-mail: susanne.doerfler@chemie.tu-dresden.de [Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, 01069 Dresden (Germany); Hampel, Silke, E-mail: s.hampel@ifw-dresden.de [Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Institute for Solid State Research, Helmholtzstr. 20, 01069 Dresden (Germany); Grothe, Julia, E-mail: stefan.kaskel@chemie.tu-dresden.de [Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, 01069 Dresden (Germany); Kaskel, Stefan, E-mail: julia.grothe@chemie.tu-dresden.de [Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, 01069 Dresden (Germany)

    2014-12-15

    Polydopamine, formed by oxidation of dopamine, is a bioinspired polymer developed for multifunctional coatings by Lee et al. in 2007 by drawing inspiration from the adhesive proteins found in mussels. Due to their high versatility and substrate-independence, polydopamine coatings are gaining considerable attention in a plethora of research fields, particularly in the coating of particles, but systematic investigations of the polydopamine coating process are lacking in the literature. In this study, we explore by TEM and thermogravimetric analysis the polydopamine coating process on alumina microparticles, tungsten carbide microparticles and tungsten carbide nanoparticles. By choosing two substrates with similar size but different material (Al{sub 2}O{sub 3} and WC), as well as two substrates of the same material but different size (WC micro- and nanoparticles) we investigate the effects of both substrate material and substrate size, in order to gain some insights into the polydopamine particle coating process. As opposed to what is generally assumed in the literature, we found that the polydopamine coating thicknesses on particles, as well as the thickness growing trend, depend on the particles size and material. In particular, after 24 h of polymerization time the polydopamine coatings reached a thickness of 65 ± 10 nm in the case of Al{sub 2}O{sub 3} microparticles, 18 ± 4 nm in the case of WC microparticles and 33 ± 6 nm in the case of WC nanoparticles. - Highlights: • The coating of different particles with polydopamine was systematically investigated. • Al{sub 2}O{sub 3} microparticles and WC microparticles and nanoparticles were investigated. • The thickness of the polydopamine coating depends on the particle size. • The thickness of the polydopamine coating depends on the particle material.

  12. Magnetic relaxation phenomena and inter-particle interactions in nanosized gamma-Fe sub 2 O sub 3 systems

    CERN Document Server

    Predoi, D; Tronc, E; Nogues, M; Russo, U; Principi, G; Filoti, G

    2003-01-01

    Samples of gamma-Fe sub 2 O sub 3 nano-particles with a mean size of 4.0(3) nm and with different hydration and surfactant degrees were prepared by sol-gel methods. Morphology and structural data were obtained by transmission electron microscopy and x-ray diffraction, whereas the surface effects and hyperfine interactions were analysed mainly by Moessbauer spectroscopy. The relative number of surface iron positions was found to be proportional to the amount of OH sup - and SO sub 4 sup 2 sup - groups on the particle surface, which in turn is strictly dependent on the preparation conditions. Strong relaxation processes versus temperature were evidenced in the analysed systems. New criteria for the evaluation of the blocking temperature via Moessbauer measurements are proposed. The results are in good agreement with blocking temperatures obtained by magnetic measurements. Moreover, it was shown that the inter-particle magnetic interactions decrease with the number of iron surface states.

  13. Low field magnetoresistance effects in fine particles of La sub 0 sub . sub 6 sub 7 Ca sub 0 sub . sub 3 sub 3 MnO sub 3 perovskites

    CERN Document Server

    Rivas, J; Fondado, A; Rivadulla, F; López-Quintela, M A

    2000-01-01

    In this work magnetic and magnetotransport experimental data in well-characterized small particles of La sub 0 sub . sub 6 sub 7 Ca sub 0 sub . sub 3 sub 3 MnO sub 3 are presented. Grain size reduction leads to a larger resistivity and a decrease in metal-insulator transition temperature. Intrinsic colossal magnetoresistance (CMR) is destroyed while intergranular one is promoted to larger values. This low field MR can be explained taking into account magnetization data through spin-polarized tunneling model, which ensures an acceptable first-order fit between both magnitudes. Finally, low-temperature resistivity upturn present in small particle size samples can be understood in terms of an electrostatic barrier between grains.

  14. Effect of particle size and volume fraction of BaTiO{sub 3} powders on the functional properties of BaTiO{sub 3}/poly(ε-caprolactone) composites

    Energy Technology Data Exchange (ETDEWEB)

    Airimioaei, M., E-mail: mirela.airimioaei@yahoo.com [Dielectrics, Ferroelectrics & Multiferroics Group, Department of Physics, “Al. I. Cuza” University of Iasi, Blv. Carol I, nr.11, 700506, Iasi (Romania); Stanculescu, R.; Preutu, V.; Ciomaga, C.; Horchidan, N. [Dielectrics, Ferroelectrics & Multiferroics Group, Department of Physics, “Al. I. Cuza” University of Iasi, Blv. Carol I, nr.11, 700506, Iasi (Romania); Tascu, S. [Interdisciplinary Research Department – Field Science (RAMTECH), “Al. I. Cuza” University of Iasi, Blv. Carol I, nr.11, 700506, Iasi (Romania); Lutic, D.; Pui, A. [Faculty of Chemistry, “Al. I. Cuza” University of Iasi, 700506, Iasi (Romania); Mitoseriu, L., E-mail: lmtsr@uaic.ro [Dielectrics, Ferroelectrics & Multiferroics Group, Department of Physics, “Al. I. Cuza” University of Iasi, Blv. Carol I, nr.11, 700506, Iasi (Romania)

    2016-10-01

    A systematic study concerning the effect of particle size and volume fraction of BaTiO{sub 3} filler on the functional properties of composite materials with poly-(ε-caprolactone) polymer matrix obtained by solvent casting method was performed. Two series of xBT-(1-x)PCL composites prepared by using BaTiO{sub 3} powders with two different particles size (60 nm and 400 nm) in different amounts (x = 2; 5; 10 and 20 vol %) were investigated. The X-ray diffraction analysis indicated a particle size dependence of phase symmetry for BT filler powders (cubic phase for ultrafine particles and tetragonal phase for larger particles size) and the formation of pure composites consisting of orthorhombic PCL and cubic or tetragonal BT with no chemical reactions between them. The micrographs of the composites revealed the formation of homogeneous composites with two distinct phases, a good dispersion of ferroelectric phase into the polymer matrix and a low content of air pores. Dielectric investigations at room temperature showed the increases of permittivity with increasing the particle volume fraction of ferroelectric filler as result of the “sum property” of the effective permittivity in composites. For a given concentration, the permittivity of composites increases with particle size, as result of a size effect of BT powder. The composites with low BT addition presents stable dielectric properties at bending cycles. The polarization-field dependences also show a BT-induced size dependence, i.e. at a given value of field, polarization is higher for the composites with coarser BT particles. The composition x = 0.05 with coarse particles can be considered as an optimum among these series for the stored energy density. - Highlights: • Study of particles size effect of BT on the properties of composites with PCL matrix. • xBT-(1-x)PCL composite films were prepared by solvent casting method. • Homogeneous composites with good dispersion of BT filler PCL matrix were

  15. Facile synthesis, characterization, and electrochemical performance of multi-scale AgVO{sub 3} particles

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hangkong [Department of Civil Engineering, The University of Hong Kong, Pokfulam Road (Hong Kong); Li, Hailong [Department of Civil Engineering, The University of Hong Kong, Pokfulam Road (Hong Kong); School of Energy Science and Engineering, Central South University, Changsha, Hunan 410083 (China); Wu, Shaokang [School of Energy Science and Engineering, Central South University, Changsha, Hunan 410083 (China); Liao, Changzhong; Zhou, Zhengyuan [Department of Civil Engineering, The University of Hong Kong, Pokfulam Road (Hong Kong); Liu, Xiang; Djurišić, Aleksandra B.; Xie, Maohai [Department of Physics, The University of Hong Kong, Pokfulam Road (Hong Kong); Tang, Chuyang [Department of Civil Engineering, The University of Hong Kong, Pokfulam Road (Hong Kong); Shih, Kaimin, E-mail: kshih@hku.hk [Department of Civil Engineering, The University of Hong Kong, Pokfulam Road (Hong Kong)

    2016-07-25

    Multi-scale AgVO{sub 3} particles were successfully synthesized from different organic acids using a facile sol–gel method; a series of techniques were then used to characterize the particles. The X-ray Diffraction (XRD) patterns showed that a main characteristic peak of element Ag is at around 38°. The X-ray photoelectron spectroscopy (XPS) spectra demonstrated the binding energies of Ag{sup 0} 3d (5/2) and Ag{sup 0} 3d (3/2), which further confirmed the existence of element Ag. In addition, the composition of the samples, including the amorphous phase, was determined with a quantitative X-ray diffraction (QXRD) analysis. With a heating rate of 10 °C/min, the products synthesized with citric acid at 450 °C had a larger amorphous phase (26.4% in wt.%) than the samples synthesized with citric acid at 500 °C. To obtain lesser amorphous phase, the precursors were treated at 500 °C with a slower heating rate of 5 °C/min. The electrochemical performance of these three samples, particularly their suitability as cathode materials for lithium ion batteries, were investigated. The products with minimum amorphous phase (9.4%) showed higher specific discharge capacity than other two samples at the first 40 cycles. However, with the increasing fading rate, only 27% of the initial capacity was retained after 100 cycles. Amorphous phase can stabilize the material and avoid the structural collapse during the cycles. Therefore, under the synergistic effect of amorphous content and particle size, the products obtained at 500 °C with quicker heating rate exhibited the optimal capacity and cycling stability. This electrode showed a high initial capacity of 243 mA h/g and retained 41% of the initial capacity after 100 cycles. - Highlights: • Multi-scale AgVO{sub 3} particles were synthesized successfully via a sol–gel method. • With a series of characterization techniques, the existence of Ag was confirmed. • The effects of amorphous phase on the electrochemical

  16. In Situ Synthesis of Field-responsive Nanocrystalline BaTiO{sub 3} Particles Modified with Functional Organics

    Energy Technology Data Exchange (ETDEWEB)

    Yogo, Toshinobu [Nagoya University, Nanomaterials Science, EcoTopia Science Institute (Japan)], E-mail: yogo@esi.nagoya-u.ac.jp; Fukuzawa, Reimon [Nagoya University, Department of Applied Chemistry, Graduate School of Engineering (Japan); Sakamoto, Wataru [Nagoya University, Nanomaterials Science, EcoTopia Science Institute (Japan); Hirano, Shin-ichi [Nagoya University, Department of Applied Chemistry, Graduate School of Engineering (Japan)

    2005-12-15

    Nanocrystalline BaTiO{sub 3} particles modified with polarizable ligands were synthesized through hydrolysis of modified metal-organics below 100 deg. C. BaTiO{sub 3} precursor was synthesized from barium metal, titanium isopropoxide and polarizable ligands in a mixture of ethanol and 2-ethoxyethanol. The modified Ba-Ti complex alkoxide was hydrolyzed yielding BaTiO{sub 3} particles modified with organics. The crystallinty of nanometer-sized particles was dependent upon the hydrolysis conditions, and increased with increasing water amount and time. The nanocrystalline particles were identified to be BaTiO{sub 3} by X-ray diffraction (XRD) and electron diffraction. A fluid consisting of modified BaTiO{sub 3} particles and silicone oil revealed a typical electrorheological (ER) behavior on applying DC field. The ER behavior was found to depend upon the kind of ligand. 4-Fluorobenzyloxy modifier revealed the highest yield stress in the ER measurement among 4-substituted benzyloxy ligands examined.

  17. Directly Addressable Sub-3 nm Gold Nanogaps Fabricated by Nanoskiving Using Self-Assembled Monolayers as Templates

    NARCIS (Netherlands)

    Pourhossein, Parisa; Chiechi, Ryan C.

    This paper describes the fabrication of electrically addressable, high-aspect-ratio (>10000:1) nanowires of gold with square cross sections of 100 nm on each side that are separated by gaps of 1.7-2.2 nm which were defined using self-assembled monolayers (SAMs) as templates. We fabricated these

  18. Electrical characteristics of 25 nm Pr(ZrTi)O{sub 3} thin films grown on Si by metalorganic chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Lin, C. H. [Materials Research Laboratory, Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Friddle, P. A. [Materials Research Laboratory, Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Lu, X. [Materials Research Laboratory, Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Chen, Haydn [Materials Research Laboratory, Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Kim, Young [Material Research Laboratory, Center for Microanalysis of Materials, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Wu, T. B. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan, Republic of China (China)

    2000-08-15

    Pb(Zr{sub 0.5}Ti{sub 0.5})O{sub 3} thin films 25 nm in thickness were grown on LaNiO{sub 3}/Pt/Ti buffered Si substrates at 600 degree sign C by metalorganic chemical vapor deposition. P-E studies showed a remanent polarization value of 8 {mu}C/cm{sup 2} with a coercive field of 200 kV/cm. In polarization fatigue studies, these films only showed slight degradation in remanent polarization up to 4x10{sup 8} cycles ({+-}3 V oscillation) before breakdown. Moreover, the effect of space charge on the C-V behavior of these films was illustrated I-V characteristics of these films were also described. (c) 2000 American Institute of Physics.

  19. ANTS-anchored Zn-Al-CO{sub 3}-LDH particles as fluorescent probe for sensing of folic acid

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Pengfei; Liu, Dan; Liu, Yanhuan [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Beijing Key Laboratory of Environmentally Harmful Chemical Analysis, Beijing University of Chemical Technology, Beijing 100029 (China); Li, Lei, E-mail: lilei@mail.buct.edu.cn [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Beijing Key Laboratory of Environmentally Harmful Chemical Analysis, Beijing University of Chemical Technology, Beijing 100029 (China)

    2016-09-15

    A novel fluorescent nanosensor for detecting folic acid (FA) in aqueous media has been developed based on 8-aminonaphthalene-1,3,6-trisulfonate (ANTS) anchored to the surface of Zn-Al-CO{sub 3}-layered double hydroxides (LDH) particles. The nanosensor showed high fluorescence intensity and good photostability due to a strong coordination interaction between surface Zn{sup 2+} ions of Zn-Al-CO{sub 3}-LDH and N atoms of ANTS, which were verified by result of X-ray photoelectron spectroscopy (XPS). ANTS-anchored on the surface of Zn-Al-CO{sub 3}-LDH restricted the intra-molecular rotation leading to ANTS-anchored J-type aggregation emission enhancement. ANTS-anchored Zn-Al-CO{sub 3}-LDH particles exhibited highly sensitive and selective response to FA over other common metal ions and saccharides present in biological fluids. The proposed mechanism was that oxygen atoms of -SO{sub 3} groups in ANTS-anchored on the surface of Zn-Al-CO{sub 3}-LDH were easily collided by FA molecules to form potential hydrogen bonds between ANTS-anchored and FA molecules, which could effectively quench the ANTS-anchored fluorescence. Under the simulated physiological conditions (pH of 7.4), the fluorescence quenching was fitted to Stern-Volmer equation with a linear response in the concentration range of 1 μM to 200 μM with a limit of detection of 0.1 μM. The results indicate that ANTS-anchored Zn-Al-CO{sub 3}-LDH particles can afford a very sensitive system for the sensing FA in aqueous solution. - Highlights: • A novel fluorescent nanosensor has been developed. • The sensor exhibited highly sensitive and selective response to FA. • The fluorescence quenching was fitted to Stern–Volmer equation. • The linear response range was 1–200 μM with a limit of detection of 0.1 μM.

  20. Solid-particle erosion of an Al{sub 2}O{sub 3}-SiC-TiC composite

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, M.; Goretta, K.C.; Singh, D.; Routbort, J.L. [Argonne National Lab., IL (United States); Schuldies, J.J. [Industrial Ceramic Technology, Inc., Ann Arbor, MI (United States)

    1996-11-01

    An electrodischarge-machinable Al{sub 2}O{sub 3}-SiC-TiC composite developed by Industrial Ceramic Technology, Inc., has a high fracture toughness, 9.6{+-}0.6 MPm{sup 1/2}, as measured by indentation, and a Vickers hardness of 20.3{+-}0.6 GPa. The composite`s resistance to solid-particle erosion was measured for 143-{mu}m dia SiC particles impacting at 20-90{degree} angles and 50-100 m/s velocities. Erosion rate exhibited a maximum for normal incidence, and the erosion resistance was better than that of commercial Al{sub 2}O{sub 3}. SEM indicated that material wastage was by a combination of brittle fracture and microplasticity.

  1. Oxidative Dehydrogenation of Cyclohexane on Cobalt Oxide (Co<sub>3O4) Nanoparticles: The Effect of Particle Size on Activity and Selectivity

    Energy Technology Data Exchange (ETDEWEB)

    Tyo, Eric C.; Yin, Chunrong; Di Vece, Marcel; Qian, Qiang; Kwon, Gihan; Lee, Sungsik; Lee, Byeongdu; DeBartolo, Janae E.; Seifert, Sönke; Winans, Randall E.; Si, Rui; Ricks, Brian; Goergen, Simone; Rutter, Matthew; Zugic, Branko; Flytzani-Stephanopoulos, Maria; Wang, Zhi Wei; Palmer, Richard E.; Neurock, Matthew; Vajda, Stefan

    2012-10-02

    The oxidative dehydrogenation of cyclohexane by cobalt oxide nanoparticles was studied via temperature programmed reaction combined with in situ grazing incidence X-ray absorption spectroscopy and grazing incidence small-angle X-ray scattering and theoretical calculations on model Co<sub>3O4 substrates. Both 6 and 12 nm Co<sub>3O4 nanoparticles were made through a surfactant-free preparation and dispersed on an Al2O<sub>3 surface formed by atomic layer deposition. Under reaction conditions the nanoparticles retained their oxidation state and did not sinter. They instead underwent an assembly/disassembly process and could reorganize within their assemblies. The selectivity of the catalyst was found to be size- and temperature-dependent, with larger particles preferentially producing cyclohexene at lower temperatures and smaller particles predominantly resulting in benzene at higher temperatures. The mechanistic features thought to control the oxidative dehydrogenation of cyclohexane and other light alkanes on cobalt oxide were established by carrying out density functional theory calculations on the activation of propane, a surrogate model alkane, over model Co<sub>3O4 surfaces. The initial activation of the alkane (propane) proceeds via hydrogen abstraction over surface oxygen sites. The subsequent activation of the resulting alkoxide intermediate occurs at a second surface oxygen site to form the alkene (propene) which then desorbs from the surface. Hydroxyl recombination results in the formation of water which desorbs from the surface. Finally, oxygen is necessary to regenerate the surface oxygen sites, catalyze C–H activation steps, and minimize catalyst degradation.

  2. Effect of organic solvents on particle size of Mn{sub 3}O{sub 4} nanoparticles synthesized by a solvothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Song, Rui [Research Institute, Jilin Petrochemical Company Ltd., Jilin 132021 (China); Feng, Shouhua, E-mail: shfeng@mail.jlu.edu.cn [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012 (China); Wang, Hongjun [Sales and Management Department, Jilin Petrochemical Company Ltd., Jilin 132002 (China); Hou, Changmin [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012 (China)

    2013-06-15

    In this paper, a modified simple solvothermal method is employed to synthesize Mn{sub 3}O{sub 4} nanocrystals using four different solvents: acetone, ethanol, N,N-dimethylformamide (DMF), and dimethyl sulfoxide (DMSO). Mn{sub 3}O{sub 4} nanoparticles with a tetragonal hausmannite nano-structure are characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FTIR), as well as superconducting quantum interference device magnetometer (SQUID). The Mn{sub 3}O{sub 4} particle size is found to have a strong dependency on the solvent used. A reaction scheme is proposed to understand this dependency, suggesting that the solvent coordinating capability has a critical effect on Mn{sub 3}O{sub 4} particle size. The stronger the coordinating capability of the solvent is, the smaller the Mn{sub 3}O{sub 4} particle size is. In addition, magnetic properties of the nano-structured Mn{sub 3}O{sub 4} are also tested and discussed. - Graphical abstract: The comparison of the particle size of Mn{sub 3}O{sub 4} nanoparticles synthesized using different solvents and HRTEM image of Mn{sub 3}O{sub 4} individual nanoparticle revealed its single-crystal nature. - Highlights: • Mn{sub 3}O{sub 4} nanocrystals were synthesized using different solvents by a solvothermal method. • The particle size of Mn{sub 3}O{sub 4} nanocrystal is found to have a strong dependency on the solvent used. • A reaction mechanism is proposed to explain the difference of particle size of Mn{sub 3}O{sub 4} nanocrystals. • Magnetic properties of Mn{sub 3}O{sub 4} nanocrystals with different particle size are tested and compared.

  3. Electromagnetic properties of multiferroic magnetoelectric BaTiO{sub 3}-Co{sub x}Fe{sub 3-x}O{sub 4} core-shell particles obtained by homogeneous coprecipitation

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Mei, E-mail: yumei@buaa.edu.cn [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Hu, Jingzhi [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Liu, Jianhua, E-mail: liujh@buaa.edu.cn [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Li, Songmei [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China)

    2013-01-15

    Electromagnetic properties of multiferroic magnetoelectric core-shell structured BaTiO{sub 3}-Co{sub x}Fe{sub 3-x}O{sub 4} composite particles synthesized by homogeneous coprecipitation method were studied. The complex permeability and permittivity of samples prepared with different R values (the molar ratio of FeCl{sub 2}{center_dot}4H{sub 2}O to CoCl{sub 2}{center_dot}6H{sub 2}O, M(FeCl{sub 2}{center_dot}4H{sub 2}O)/M(CoCl{sub 2}{center_dot}6 H{sub 2}O)) during the coprecipitation processes were measured in the frequency range of 2-8 GHz by a network vector analyzer. The result showed that the electromagnetic parameters of BaTiO{sub 3}-Co{sub x}Fe{sub 3-x}O{sub 4} core-shell particles could be controlled effectively by adjusting the R value of reaction solution. The increasing R value intensified the interfacial polarization process, leading the {epsilon} Prime value of BaTiO{sub 3}-Co{sub x}Fe{sub 3-x}O{sub 4} core-shell particles to increase and the fluctuation of {epsilon} Double-Prime curves to become obvious. Meanwhile, the increasing R value enhanced M{sub s} and adjusted the direction of easy magnetization axis, which resulted in the {mu} Prime value of BaTiO{sub 3}-Co{sub x}Fe{sub 3-x}O{sub 4} core-shell particles getting increased and the resonance peak of {mu} Double-Prime moving to a higher frequency. The increased complex permeability and permittivity also resulted in an improvement of dielectric and magnetic loss. - Highlights: Black-Right-Pointing-Pointer We studied electromagnetic properties of BaTiO{sub 3}-Co{sub x}Fe{sub 3-x}O{sub 4} core-shell particles. Black-Right-Pointing-Pointer The molar ratio of FeCl{sub 2}{center_dot}4H{sub 2}O to CoCl{sub 2}{center_dot}6 H{sub 2}O(R) controls electromagnetic parameters. Black-Right-Pointing-Pointer Interfacial polarization adjusted by R affects {epsilon} Prime value and the fluctuation of {epsilon} Double-Prime . Black-Right-Pointing-Pointer M{sub s} enhanced by increasing R makes the {mu} Prime increase

  4. Effect of particle size distribution on the magnetic properties {gamma}-Fe{sub 2}O{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Hassnain Jaffari, G. [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Department of Physics, Quaid-i-Azam University, Islamabad (Pakistan); Ekiert, Thomas; Unruh, K.M. [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Ismat Shah, S., E-mail: ismat@udel.edu [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716 (United States)

    2012-07-25

    Highlights: Black-Right-Pointing-Pointer Effects of particle size distribution on magnetic properties of {gamma}-Fe{sub 2}O{sub 3} nanoparticles are studied. Black-Right-Pointing-Pointer A new measurement is carried out in which spins were thermally activated below blocking temperature under constant field. Black-Right-Pointing-Pointer Simulations on non-interacting nanoparticle system are compared with experiment. Black-Right-Pointing-Pointer The magnetization differences at the temperature below and around blocking temperature are discussed. Black-Right-Pointing-Pointer Experimental results show reversible magnetization on subsequent cooling-heating cycles. - Abstract: The magnetic response of nanocomposites formed by non-interacting well dispersed {gamma}-Fe{sub 2}O{sub 3} nanoparticles in a polymer matrix is presented. Various low loading fraction of particles in polymer leads to an observation of similar values of blocking temperatures and coercive fields. ac response confirms that particles are non-interacting and follow Neel-Brown model. Effect of particle size distribution on hysteresis behavior and saturation magnetization as a function of temperature is discussed. Since particles have a size distribution, the experimental results of magnetic response are compared with simulations based on Stoner-Wohlfarth model of single size particles. We have devised a measurement method in which a constant magnetic field was applied while the thermal energy is varied by sequentially heating and cooling the sample below the blocking temperature. Nanoparticle-polymer composites show reversible magnetization behavior for sequential heating/cooling cycles. However, simulation based on single size particle system shows irreversible magnetization behavior during the heating and cooling cycles. These observations are qualitatively explained in terms of different behavior of magnetization as a function of temperature for smaller superparamagnetic particles and larger blocked

  5. In situ trace gas and particle measurements in the summer lower stratosphere during STREAM II. Implications for O{sub 3} production

    Energy Technology Data Exchange (ETDEWEB)

    Bregman, A.; Lelieveld, J.; Scheeren, H.A. [Institute for Marine and Atmospheric Sciences, Utrecht (Netherlands); Arnold, F.; Buerger, V.; Schneider, J. [Max-Planck-Inst. for Nuclear Physics, Heidelberg (Germany); Fischer, H.; Waibel, A. [Max-Planck-Inst. fuer Chemie, Mainz (Germany); Siegmund, P.C.; Wauben, W.M.F. [Koninklijk Nederlands Meteorologisch Inst., De Bilt (Netherlands); Stroem, J. [Stockholm Univ. (Sweden). Dept. of Meteorology

    1997-12-31

    In situ aircraft measurements of O{sub 3}, CO, HNO{sub 3}, and aerosol particles are presented, performed over the North Sea region in the summer lower stratosphere during the STREAM-II campaign (Stratosphere Troposphere Experiments by Aircraft Measurements). Elevated CO mixing ratios are attributed to mixing of polluted tropospheric air into the lowermost extra-tropical stratosphere. Model calculations illustrate that the O{sub 3} production efficiency of NO{sub x} is smaller than previously assumed, under conditions with relatively high HNO{sub 3} mixing ratios, as observed during STREAM-II. The model simulations further suggest a relatively high O{sub 3} production efficiency from CO oxidation, as a result of the relatively high ambient HNO{sub 3} and NO{sub x} concentrations, implying that upward transport of CO rich air enhances O{sub 3} production in the lowermost stratosphere. (author) 13 refs.

  6. Effect of particle size and strain on phase stability of (Li{sub 0.06} Na{sub 0.94}) NbO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, S. K., E-mail: skmsspd@barc.gov.in; Shinde, A. B.; Krishna, P. S. R. [Solid State Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai-40085 (India)

    2014-05-07

    Alkaline niobates are most suitable and excellent candidates for lead free piezoceramics, as they exhibit morphotropic phase boundary and have ultra-large piezoresponse similar to them. We provide direct experimental evidence of ferroelectric to paraelectric phase transition in (Li{sub 0.06} Na{sub 0.94})NbO{sub 3} with reduction of particle size using a combination of x-ray and neutron powder diffraction techniques at room temperature. Detailed Rietveld analyses of x-ray data show variation of particle sizes from micrometer to nanometer for sintered, calcined, and ball milled powders. The ferroelectric orthorhombic phase for micron sized powder (∼1.17 μm) is found to transform to paraelectric phase by reducing particle size to ∼10.8 nm. The crystal structure of paraelectric phase has been identified with tetragonal symmetry (P4{sub 2}/mmc) and is found to be a post perovskite phase. The low temperature neutron diffraction studies on the powders with different particle sizes reveal that orthorhombic to rhombohedral phase transition gets suppressed with reducing particle size.

  7. Influence of Pt particles on the porosity of Al{sub 2}O{sub 3} coating prepared by cathode plasma electrolytic deposition

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Peng [Beijing Key Laboratory for Corrosion, Erosion and Surface Technology, University of Science and Technology Beijing, 100083, Beijing (China); Research Institute of Aerospace Special Materials and Processing Technology, 100074, Beijing (China); He, Yedong, E-mail: htgroup@mater.ustb.edu.cn [Beijing Key Laboratory for Corrosion, Erosion and Surface Technology, University of Science and Technology Beijing, 100083, Beijing (China); Zhang, Jin [Beijing Key Laboratory for Corrosion, Erosion and Surface Technology, University of Science and Technology Beijing, 100083, Beijing (China)

    2016-12-01

    Porous Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}-Pt coatings were successfully prepared on the Ni-based alloy by cathode plasma electrolytic deposition. It is found that the porosity of coatings can be reduced obviously by Pt particles co-deposited with Al{sub 2}O{sub 3}. This phenomenon can be attributed to that the mechanism of plasma discharge is changed in such CPED. As the Pt particles are dispersed in the Al{sub 2}O{sub 3} coating, the electron avalanche is difficult to occur. So, the breakdown takes place in the Al{sub 2}O{sub 3}-Pt coating difficultly, the destructive effect of the breakdown will therefore be decreased, and the porosity of Al{sub 2}O{sub 3} coating can be reduced which has been verified by the results of surface morphologies of the coatings. - Highlights: • The Al{sub 2}O{sub 3}-Pt coatings were prepared on Ni-based alloys by CPED. • The porosity of coating is reduced obviously by Pt particles dispersed with Al{sub 2}O{sub 3}. • The related mechanisms of plasma discharge in CPED were discussed.

  8. Study on the synthesis and formation mechanism of flower-like Cu{sub 3}SbS{sub 4} particles via microwave irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Guilin, E-mail: glchen@fjnu.edu.cn [Fujian Provincial Key Laboratory of Quantum Manipulation and New Energy Materials, College of Physics and Energy, Fujian Normal University, Fuzhou, 350007 (China); Fujian Provincial Collaborative Innovation Center for Optoelectronic Semiconductors and Efficient Devices, Xiamen, 361005 (China); Wang, Weihuang; Zhao, Jifu; Yang, Wenyu [Fujian Provincial Key Laboratory of Quantum Manipulation and New Energy Materials, College of Physics and Energy, Fujian Normal University, Fuzhou, 350007 (China); Chen, Shuiyuan; Huang, Zhigao [Fujian Provincial Key Laboratory of Quantum Manipulation and New Energy Materials, College of Physics and Energy, Fujian Normal University, Fuzhou, 350007 (China); Fujian Provincial Collaborative Innovation Center for Optoelectronic Semiconductors and Efficient Devices, Xiamen, 361005 (China); Jian, Rongkun; Ruan, Huirong [Department of Materials Science and Engineering, Fujian Normal University, Fuzhou, 350007 (China)

    2016-09-15

    The future development of Cu{sub 3}SbS{sub 4} as an alternative absorber for low cost and high efficiency thin film solar cell depends strongly on the understanding of the formation of mechanism in this system. With this aim, a detailed characterization of Cu{sub 3}SbS{sub 4} particles prepared by microwave irradiation is presented, combining XRD, SEM, and EDX. The development of Cu{sub 3}SbS{sub 4} formation with the increasement of temperature and the prolongation of time are investigated by depth-resolved analysis. Under such conditions, a reaction pathway for the formation of Cu{sub 3}SbS{sub 4} from binary and CuSbS{sub 2} compounds as intermediates is proposed. The experimental data supports a formation mechanism of Cu{sub 3}SbS{sub 4} that proceeds rapidly when the CuSbS{sub 2} react with the remaining binary phases CuS. During reaction Cu is completely consumed, while Sb is lost through the way of Sb{sub 2}S{sub 3} vapor. - Highlights: • Flower-like Cu{sub 3}SbS{sub 4} particles were synthesized by microwave irradiation route. • A series of time-dependent experiments were designed to study the growth mechanism of the Cu{sub 3}SbS{sub 4}. • During reaction, the phase content transitions from rich-Sb{sub 2}S{sub 3} and CuS, through to CuSbS{sub 2}, and finally Cu{sub 3}SbS{sub 4}. • This work provides a solid platform for further preparation of pure Cu{sub 3}SbS{sub 4}.

  9. Evaluation of size exclusion chromatography columns packed with sub-3μm particles for the analysis of biopharmaceutical proteins.

    Science.gov (United States)

    Goyon, Alexandre; Beck, Alain; Colas, Olivier; Sandra, Koen; Guillarme, Davy; Fekete, Szabolcs

    2017-05-19

    The aim of this study was to evaluate the practical possibilities and limitations of several recently introduced size exclusion chromatographic (SEC) columns of 150×4.6mm, sub-3μm (Agilent AdvanceBioSEC 2.7μm, Tosoh TSKgel UP-SW3000 2.0μm, Phenomenex Yarra SEC X-150 1.8μm and Waters Acquity BEH200 1.7μm) for the separation of biopharmaceutical proteins. For this purpose, some model proteins were tested, as well as several commercial therapeutic monoclonal antibodies (mAbs) and antibody-drug-conjugates (ADCs). Calibration curves were drawn to highlight the applicability of these new SEC columns for the separation of mAbs, ADCs and their aggregates, despite some differences in their nominal pore diameter (vary from 150 to 300Å). The kinetic performance (van Deemter curves and kinetic pots) was evaluated. Columns packed with 1.7-2.0μm particles improved the plate count by a factor of 1.5-2 compared to 2.7μm particles, which is in agreement with theoretical expectations. Finally, possible secondary hydrophobic and/or electrostatic interactions between the SEC stationary phases and biopharmaceutical proteins were systematically studied. Significant differences in nonspecific interactions were observed, with hydrophobic interactions generally exerting more influence than electrostatic interactions. The use of a novel bond chemistry with the AdvanceBioSEC column was found highly effective to limit non-specific interactions and pave the way to further improvements for column provider. At the end, the average resolutions achieved on the four sub-3μm SEC columns between monomer and dimer structures were comparable for ten approved mAbs products. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Nanocrystalline Cs{sub x}WO{sub 3} particles: Effects of N{sub 2} annealing on microstructure and near-infrared shielding characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jing-Xiao, E-mail: drliu-shi@dlpu.edu.cn [School of Textile and Material Engineering, Dalian Polytechnic University, Dalian 116034 (China); Institute of Multidisciplinary Research for Advanced Material, Tohoku University, Sendai, 980-8577,Japan (Japan); Shi, Fei; Dong, Xiao-Li; Xu, Qiang [School of Textile and Material Engineering, Dalian Polytechnic University, Dalian 116034 (China); Yin, Shu; Sato, Tsugio [Institute of Multidisciplinary Research for Advanced Material, Tohoku University, Sendai, 980-8577,Japan (Japan)

    2013-10-15

    In order to further improve the near-infrared shielding properties of cesium tungsten bronze (Cs{sub x}WO{sub 3}) for solar filter applications, Cs{sub x}WO{sub 3} particles were prepared by solvothermal reaction method and the effects of nitrogen annealing on the microstructure and near-infrared shielding properties of Cs{sub x}WO{sub 3} were investigated. The obtained Cs{sub x}WO{sub 3} samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and spectrophotometer. The results indicate that nanosheet-like Cs{sub x}WO{sub 3} particles with hexagonal structure began to transform into nanorods after annealed at temperature higher than 600 °C. The near-infrared shielding properties of Cs{sub x}WO{sub 3} particles could be further improved by N{sub 2} annealing at 500–700 °C. Particularly, the 500 °C-annealed Cs{sub x}WO{sub 3} samples in the N{sub 2} atmosphere showed best near-infrared shielding properties. It was suggested that the excellent near-infrared shielding ability of the 500 °C-annealed Cs{sub x}WO{sub 3} samples is correlated with its minimum O/W atomic ratio and most oxygen vacancies. Highlights: • N{sub 2} annealing could further improve the near-infrared (NIR) shielding of Cs{sub x}WO{sub 3}. • Effects of N{sub 2} annealing on microstructure and NIR shielding of Cs{sub x}WO{sub 3} were studied. • The 500 °C-N{sub 2}-annealed Cs{sub x}WO{sub 3} exhibited minimum O/W ratio and most oxygen vacancies. • The 500 °C-N{sub 2}-annealed Cs{sub x}WO{sub 3} particles exhibited best NIR shielding properties.

  11. A highly efficient nano-Fe{sub 3}O{sub 4} encapsulated-silica particles bearing sulfonic acid groups as a solid acid catalyst for synthesis of 1,8-dioxo-octahydroxanthene derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Naeimi, Hossein, E-mail: naeimi@kashanu.ac.ir; Nazifi, Zahra Sadat [University of Kashan, Department of Organic Chemistry, Faculty of Chemistry (Iran, Islamic Republic of)

    2013-11-15

    The functionalization of silica-coated Fe{sub 3}O{sub 4} magnetic nanoparticles (Fe{sub 3}O{sub 4}@SiO{sub 2}) using chlorosulfonic acid were afforded sulfonic acid-functionalized magnetic Fe{sub 3}O{sub 4} nanoparticles (Fe{sub 3}O{sub 4}@SiO{sub 2}–SO{sub 3}H) that can be applied as an organic–inorganic hybrid heterogeneous catalyst. The used Fe{sub 3}O{sub 4} magnetic nanoparticles are 18–30 nm sized that was rapidly functionalized and can be used as catalyst in organic synthesis. The prepared nanoparticles were characterized by X-ray diffraction analysis, magnetization curve, scanning electron microscope, dynamic laser scattering, and FT-IR measurements. The resulting immobilized catalysts have been successfully used in the synthesis of 1,8‐dioxo-octahydroxanthene derivatives under solvent free condition. This procedure has many advantages such as; a much milder method, a shorter reaction time, a wide range of functional group tolerance, and absence of any tedious workup or purification. Other remarkable features include the catalyst can be reused at least five times without any obvious change in its catalytic activity. This procedure also avoids hazardous reagents/solvents, and thus can be an eco-friendly alternative to the existing methods.Graphical AbstractA highly efficient nano-Fe{sub 3}O{sub 4} encapsulated-silica particles bearing sulfonic acid groups as a solid acid catalyst for synthesis of 1,8-dioxo-octahydroxanthene derivatives.

  12. Effect of particle size and adsorbates on the L{sub 3}, L{sub 2} and L{sub 1} x-ray absorption near edge structure of supported Pt nanoparaticles.

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Y.; Jelic, J.; Nitsche, L. C.; Meyer, R.; Miller, J. (Chemical Sciences and Engineering Division); (Univ. of Illinois at Chicago)

    2011-04-01

    Pt nano-particles from about 1 to 10 nm have been prepared on silica, alkali-silica, alumina, silica-alumina, carbon and SBA-15 supports. EXAFS spectra of the reduced catalysts in He show a contraction of the Pt-Pt bond distance as particle size is decreased below 3 nm. The bond length decreased as much as 0.13 {angstrom} for 1 nm Pt particles. Adsorption of CO and H{sub 2} lead to a increase in Pt-Pt bond distance to that near Pt foil, e.g., 2.77 {angstrom}. In addition to changes in the Pt bond distance with size, as the particle size decreases below about 5 nm there is a shift in the XANES to higher energy at the L{sub 3} edge, a decrease in intensity near the edge and an increase in intensity beyond the edge. We suggest these features correspond to effects of coordination (the decrease at the edge) and lattice contraction (the increase beyond the edge). At the L{sub 2} edge, there are only small shifts to higher energy at the edge. However, beyond the edge, there are large increases in intensity with decreasing particle size. At the L{sub 1} edge there are no changes in position or shape of the XANES spectra. Adsorption of CO and H{sub 2} also lead to changes in the L{sub 3} and L{sub 2} edges, however, no changes are observed at the L1 edge. Density Functional Theory and XANES calculations show that the trends in the experimental XANES can be explained in terms of the states available near the edge. Both CO and H{sub 2} adsorption result in a depletion of states at the Fermi level but the creation of anti-bonding states above the Fermi level which give rise to intensity increases beyond the edge.

  13. Contribution to the design of superconducting Nb{sub 3}Sn dipole windings for particle accelerator; Contribution a la conception des bobinages supraconducteurs de type dipolaire en Nb{sub 3}Sn pour les accelerateurs de particules

    Energy Technology Data Exchange (ETDEWEB)

    Felice, H

    2006-10-15

    Improvement of particle accelerators relies on complex technologies such as the design and fabrication of superconducting magnets. A key parameter in magnet design is the mechanical pre-stress, applied at room temperature to insure compression of the coil during excitation. In dipole magnets, high field and high mechanical stresses in windings combined with the Nb{sub 3}Sn stress sensitivity ask the question of the limit of the mechanical stress that the Nb{sub 3}Sn can undergo without degradation. This limit estimated around 150 MPa is still discussed and has to be investigated. Whatever its value, preliminary studies show that conventional cosine theta design induces mechanical stresses (> 200 MPa) in large aperture (> 130 mm) and high field configurations, which underscore the need of alternative coil arrangements. The first part of this thesis gives an introduction to the issues and challenges encountered by the designers of superconducting ma nets. The second part is devoted to the study of large aperture (88, 130 and 160 mm) and high field (13 T) dipoles based on intersecting ellipses. After a theoretical study, a 2D magnetic design is detailed for each aperture and a mechanical study is developed for the 130 mm aperture dipole. In the last part, an experimental device dedicated to the study of the influence of the pre-stress on the training of sub-scale Nb{sub 3}Sn dipole and to the investigation of the mechanical stress limit is presented. The design of this magnet is detailed and the result of the first test carried out with the structure is reported. (author)

  14. Fluoride adsorption from aqueous solution by magnetic core-shell Fe{sub 3}O{sub 4}@alginate-La particles fabricated via electro-coextrusion

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yahui [School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, Sichuan (China); Engineering Research Center of Biomass Materials, Ministry of Education, Mianyang 621010, Sichuan (China); Lin, Xiaoyan, E-mail: lxy20100205@163.com [School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, Sichuan (China); Engineering Research Center of Biomass Materials, Ministry of Education, Mianyang 621010, Sichuan (China); Zhou, Quisheng [A State Key Laboratory of Pulp & Paper Engineering, South China University of Technology, Guangzhou 510640 (China); Luo, Xuegang [Engineering Research Center of Biomass Materials, Ministry of Education, Mianyang 621010, Sichuan (China)

    2016-12-15

    Graphical abstract: The magnetic core-shell Fe{sub 3}O{sub 4}@Alg-La particles were fabricated successfully by a simple method of electro-coextrusion, and employed as an adsorbent for separation of fluoride from aqueous solution. - Highlights: • Magnetic core-shell Fe{sub 3}O{sub 4}@Alg-La particles were prepared by electro-coextrusion. • The maximum adsorption capacity for fluoride at 298.15 K was 45.230 mg/g. • The adsorbent has a good saturation magnetization value. • The adsorbent has a great potential in removing the fluoride. - Abstract: The magnetic core-shell Fe{sub 3}O{sub 4}@Alg-La particles were fabricated successfully by a simple method of electro-coextrusion, and employed as an adsorbent for separation of fluoride from aqueous solution. Main factors affecting the removal of fluoride, including pH, adsorbent dosage, initial concentration, temperature and contact time were investigated. The adsorption isotherm and adsorption kinetics were studied to understand the adsorption process in detail. The experimental data were fitted well by the non-linear Freundlich isotherm and linear pseudo-second-order model, the maximum fluoride adsorption capacity was 45.230 mg/g at pH 4, 298.15 K. Thermodynamic parameters indicated that the fluoride adsorption process was feasible and spontaneous. The presence of other anions like Cl{sup −}, SO{sub 4}{sup 2−}, HCO{sub 3}{sup −} and PO{sub 4}{sup 3−} had almost no effect on the fluoride adsorption. The adsorbent can be easily separated from the solution by a magnet. The magnetic core-shell Fe{sub 3}O{sub 4}@Alg-La particles before and after fluoride adsorption were studied by SEM, FTIR, EDX and XPS, which indicated that the adsorption mechanism may be related to electrostatic attraction and Lewis acid-base interaction.

  15. Analysis of electrical properties of insulators (Si{sub 3}N{sub 4}, SiO{sub 2}, AlN, and Al{sub 2}O{sub 3})/0.5 nm Si{sub 3}N{sub 4}/AlGaN/GaN heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, Narihiko; Hiroki, Masanobu; Watanabe, Noriyuki; Oda, Yasuhiro; Yokoyama, Haruki; Enoki, Takatomo; Kobayashi, Takashi [NTT Photonics Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198 (Japan); Yagi, Takuma [NTT Advanced Technology Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-198 (Japan); Makimoto, Toshiki [NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198 (Japan)

    2007-06-15

    The electrical properties in AlGaN/GaN heterostructures with Si- and Al-based insulators (Si{sub 3}N{sub 4}, SiO{sub 2}, AlN, and Al{sub 2}O{sub 3}) have been examined and analyzed. By insulators deposition, significant increase in the two-dimensional electron gas (2DEG) density (N{sub s}) was observed with the order of N{sub s}(Al{sub 2}O{sub 3})>N{sub s}(AlN){proportional_to}N{sub s}(SiO{sub 2})>N{sub s}(Si{sub 3}N{sub 4})>N{sub 0} (N{sub 0}: N{sub s} without insulators). As the result, the decrease in the sheet resistance (R) was observed; the smallest order of R was R(Al{sub 2}O{sub 3})sub 3}N{sub 4})

  16. Bottom-up synthesis of up-converting submicron-sized Er{sup 3+}-doped LiNbO{sub 3} particles

    Energy Technology Data Exchange (ETDEWEB)

    Jardiel, T., E-mail: jardiel@icv.csic.es [Departamento de Electroceramica, Instituto de Ceramica y Vidrio-CSIC, Kelsen 5, 28049 Madrid (Spain); Caballero, A.C. [Departamento de Electroceramica, Instituto de Ceramica y Vidrio-CSIC, Kelsen 5, 28049 Madrid (Spain); Marin-Dobrincic, M.; Cantelar, E.; Cusso, F. [Departamento de Fisica de Materiales, C-04, Facultad de Ciencias, Universidad Autonoma de Madrid, Avda. Francisco Tomas y Valiente 7, 28049 Madrid (Spain)

    2012-08-15

    A new and simple wet chemical synthesis method is proposed to prepare submicron-sized Erbium-doped LiNbO{sub 3} powders. The synthesis procedure comprises the co-precipitation of lithium and erbium ions from common precursors and their subsequent reaction with niobium ethoxide. A systematic characterization by means of X-Ray Diffraction (XRD), X-ray Fluorescence (XRF), Inductively Coupled Plasma (ICP-OES), Atomic Absorption (AAS), Field Emission Scanning Electron Microscopy (FE-SEM), as well as by the examination of the luminescence properties, evidence that with this method a congruent Er{sup 3+}-doped LiNbO{sub 3} single phase material can be obtained without using complex and time-consuming processing steps. The synthesized powders exhibit efficient IR to VIS up-conversion emissions under 974 nm pumping. -- Highlights: Black-Right-Pointing-Pointer A novel chemical route to the preparation of LiNbO{sub 3} powders has been developed. Black-Right-Pointing-Pointer This process avoids complex and time-consuming processing steps. Black-Right-Pointing-Pointer A congruent Er{sup 3+}-doped LiNbO{sub 3} single phase material can be obtained by this way. Black-Right-Pointing-Pointer The luminescence properties are the expected for this composition.

  17. Facile fabrication of flower like self-assembled mesoporous hierarchical microarchitectures of In(OH){sub 3} and In{sub 2}O{sub 3}: In(OH){sub 3} micro flowers with electron beam sensitive thin petals

    Energy Technology Data Exchange (ETDEWEB)

    Arul Prakasam, Balasubramaniam, E-mail: arul7777@yahoo.com [Laboratory of Green Chemistry, School of Engineering Science, Lappeenranta University of Technology, Sammonkatu 12, FI-50130, Mikkeli (Finland); Lahtinen, Manu; Peuronen, Anssi [Department of Chemistry, Laboratories of Inorganic and Analytical Chemistry, P.O. Box 35, FI-40014, University of Jyväskylä (Finland); Muruganandham, Manickavachagam [Department of Civil and Environmental Engineering, Temple University, Philadelphia, PA, 19122 (United States); Sillanpää, Mika [Laboratory of Green Chemistry, School of Engineering Science, Lappeenranta University of Technology, Sammonkatu 12, FI-50130, Mikkeli (Finland)

    2016-12-01

    A template and capping-reagent free facile fabrication method for mesoporous hierarchical microarchitectures of flower-like In(OH){sub 3} particles under benign hydrothermal conditions is reported. Calcination of In(OH){sub 3} to In{sub 2}O{sub 3} with the retention of morphology is also described. Both In(OH){sub 3} and In{sub 2}O{sub 3} microstructures were analyzed with SEM, EDX, TEM and powder X-ray diffraction. The crystal sizes for In(OH){sub 3} and In{sub 2}O{sub 3} were calculated using the Scherrer equation. In In(OH){sub 3} the thin flakes at the periphery of micro flowers were electron beam sensitive. The mechanism of self-assembly process was analyzed as well. - Highlights: • Hydrothermal fabrication In(OH){sub 3} self-assembled porous hierarchical architectures. • Induced dehydration in beam sensitive In(OH){sub 3} micro flowers. • Calcination of In(OH){sub 3} to In{sub 2}O{sub 3} with the retention of flower like morphology. • Phase pure synthesis of In{sub 2}O{sub 3} with the average crystal size of ∼37 nm.

  18. Electron microscopy characterization of mechanically alloyed and hot consolidates Cu-Cr<sub>3C2 particles

    Directory of Open Access Journals (Sweden)

    López, M.

    2005-08-01

    Full Text Available Mechanically alloyed copper-ceramic composites have been obtained with the purpose of studying their use as copper-based material for electrical equipment. For high-temperature applications, dispersion-strengthened copper alloys are attractive due to their excellent combination of thermal and electrical conductivity, mechanical strength retention and microstructural stability. In this work, powder mixtures of pure copper with 2 vol % Cr<sub>3C2, milled during 4, 6, 10, 12 and 15 h in a high-energy planetary balls mill under argon atmosphere, were consolidated by hot isostatic pressing, applying a pressure of 100 MPa at 1073 K for two hours, to obtain materials with a fine microstructure. The Cu-Cr<sub>3C2 alloys were studied by scanning electron microscopy (SEM, electron microprobe (EPMA and transmission electron microscopy (TEM. Mechanical properties and electrical conductivity were also studied. The average tensile strength and electrical conductivity were found to be 500 MPa and 50 % IACS, respectively. The Cr<sub>3C2 ceramics show good stability during hot consolidation. Contributing to a further strengthening of the alloy during the hot consolidation, uniformly-distributed Fe-carbide particles of nanometric size precipitated in the copper matrix. Fe-Cr oxycarbides formed in the interphase between Cr<sub>3C2 particles and the copper matrix cause the low ductility of Cu-Cr<sub>3C2 alloys. Said particles are attributed to impurities/contamination generated from the milling process.

    Se obtuvieron aleaciones compuestas de Cu-Cr<sub>3C2, aleadas mecánicamente, para estudiar futuras aplicaciones en componentes eléctricos. A altas temperaturas, las aleaciones de base cobre reforzadas por dispersión, son atractivas por su excelente conductividad térmica y eléctrica, propiedades mecánicas y estabilidad microstructural. En este estudio

  19. Synthesis of Ce(III)-doped Fe{sub 3}O{sub 4} magnetic particles for efficient removal of antimony from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Zenglu; Joshi, Tista Prasai [Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Liu, Ruiping, E-mail: liuruiping@rcees.ac.cn [Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Liu, Huijuan [University of Chinese Academy of Sciences, Beijing 100049 (China); State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China); Qu, Jiuhui [Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)

    2017-05-05

    Highlights: • Doping of Ce into Fe{sub 3}O{sub 4} was achieved based on a facile solvothermal method. • After doping, the removal capacity was increased by 5 times for “Sb(V)” and 2 times for “Sb(III)”. • Decreasing pH improved adsorption of Sb(V) but decreased adsorption of Sb(III). • Antimony sorption mechanisms on Ce-doped Fe{sub 3}O{sub 4} were illustrated. - Abstract: Aqueous antimony (Sb) pollution from human activity is of great concern in drinking water due to its adverse health effect. Magnetic Fe{sub 3}O{sub 4} particles, with high separation ability from solution, have been considered as a low-cost Sb adsorbent for contaminants. However, the limited adsorption capacity has restricted its practical application. In this study, a solvothermal approach was developed for doping Ce(III) into Fe{sub 3}O{sub 4}, thereby increasing the adsorption efficacy for both Sb(III) and Sb(V). In contrast to un-doped Fe{sub 3}O{sub 4}, the adsorption capacity towards Sb(III) and Sb(V) in Ce-doped materials increased from 111.4 to 224.2 mg/g and from 37.2 to 188.1 mg/g at neutral pH, respectively. Based on the combined results of XPS, XRD, and FTIR, it confirmed that Ce atom successfully doped into the Fe{sub 3}O{sub 4} structure, resulting in the decreased particle size, increased the surface area, and isoelectric point. Furthermore, the vibrating sample magnetometer (VSM) results showed that the Ce doping process had some side effects on the primitive magnetic property, but remaining the high separation potential during water treatment. According to the high removal efficiency and magnetic property, the Ce-doped Fe{sub 3}O{sub 4} of great simplicity should be a promising adsorbent for aqueous Sb removal.

  20. Removal of 10-nm contaminant particles from Si wafers using CO2 bullet particles

    Science.gov (United States)

    Kim, Inho; Hwang, Kwangseok; Lee, JinWon

    2012-04-01

    Removal of nanometer-sized contaminant particles (CPs) from substrates is essential in successful fabrication of nanoscale devices. The particle beam technique that uses nanometer-sized bullet particles (BPs) moving at supersonic velocity was improved by operating it at room temperature to achieve higher velocity and size uniformity of BPs and was successfully used to remove CPs as small as 10 nm. CO2 BPs were generated by gas-phase nucleation and growth in a supersonic nozzle; appropriate size and velocity of the BPs were obtained by optimizing the nozzle contours and CO2/He mixture fraction. Cleaning efficiency greater than 95% was attained. BP velocity was the most important parameter affecting removal of CPs in the 10-nm size range. Compared to cryogenic Ar or N2 particles, CO2 BPs were more uniform in size and had higher velocity and, therefore, cleaned CPs more effectively.

  1. Magnetic and Mössbauer studies of pure and Ti-doped YFeO {sub 3} nanocrystalline particles prepared by mechanical milling and subsequent sintering

    Energy Technology Data Exchange (ETDEWEB)

    Khalifa, N. O. [University of Khartoum, Physics Department, Faculty of Science (Sudan); Widatallah, H. M., E-mail: hishammw@squ.edu.om; Gismelseed, A. M.; Al-Mabsali, F. N.; Sofin, R. G. S. [Sultan Qaboos University, Physics Department, College of Science (Oman); Pekala, M. [University of Warsaw, Chemistry Department (Poland)

    2016-12-15

    Single-phased nanocrystalline particles of pure and 10 % Ti {sup 4+}-doped perovskite-related YFeO {sub 3}were prepared via mechanosynthesis at 450{sup ∘}C. This temperature is ∼150–350 {sup ∘}C lower than those at which the materials, in bulk form, are normally prepared. Rietveld refinements of the X-ray diffraction patterns reveal that the dopant Ti {sup 4+} ions prefer interstitial octahedral sites in the orthorhombic crystal lattice rather than those originally occupied by the expelled Fe {sup 3+} ions. Magnetic measurements show canted antiferromagnetism in both types of nanoparticles. Doping with Ti {sup 4+} lowers the Néel temperature of the YFeO {sub 3} nanoparticles from ∼ 586 K to ∼ 521 K. The Ti {sup 4+}-doped YFeO {sub 3} nanoparticles exhibit enhanced magnetization and coercivity but less magnetic hyperfine fields relative to the un-doped nanoparticles. The {sup 57}Fe Mössbauer spectra show ∼ 15 % of the YFeO {sub 3} nanoparticles and ∼22 of Ti {sup 4+}-doped YFeO {sub 3} ones to be superparamagnetic with blocking temperatures < 78 K. The broadened magnetic components in the {sup 57}Fe Mössbauer spectra suggest size-dependent hyperfine magnetic fields at the {sup 57}Fe nuclear sites and were associated with collective magnetic excitations. The {sup 57}Fe Mössbauer spectra show the local environments of the Fe {sup 3+} ions in the superparamagnetic nanoparticles to be more sensitive to the presence of the Ti {sup 4+} ions relative to those in the larger magnetic nanoparticles.

  2. Phase Transformation Behavior of Oxide Particles Formed in Mechanically Alloyed Fe-5Y{sub 2}O{sub 3} Powder

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ga Eon; Choi, Jung-Sun; Noh, Sanghoon; Kang, Suk Hoon; Choi, Byoung Kwon; Kim, Tae Kyu [Korea Atomic Energy Research Institute, Deajeon (Korea, Republic of); Kim, Young Do [Hanyang University, Seoul (Korea, Republic of)

    2017-05-15

    The phase transformation behavior of the oxides formed in mechanically alloyed Fe-5Y{sub 2}O{sub 3} powder is investigated. Non-stoichiometric Y-rich and Fe-rich oxides with sizes of less than 300 nm are observed in the mechanically alloyed powder. The diffusion and redistribution reactions of the elements in these oxides during heating of the powder above 800 ℃ were observed, and these reactions result in the formation of a Y{sub 3}Fe{sub 5}O{sub 12} phase after heating at 1050 ℃. Thus, it is considered that the Y{sub 2}O{sub 3} powder and some Fe powder are formed from the non-stoichiometric Y-rich and Fe-rich oxides after the mechanical alloying process, and a considerable energy accumulated during the mechanical alloying process leads to a phase transformation of the Y-rich and Fe-rich oxides to Y{sub α}Fe{sub β}O{sub γ}-type phase during heating.

  3. Projection of SO{sub 2}, NO{sub X}, NH{sub 3} and particle emissions - 2010-2030

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, O.-K.; Plejdrup, M.; Winther, M.; Hjorth Mikkelsen, M.; Albrektsen, R.; Nielsen, M.; Fauser, P.; Hoffmann, L.; Hjelgaard, K.; Gyldenkaerne, S.

    2012-01-15

    This report contains a description of models and background data for projection of SO{sub 2}, NO{sub x}, NH{sub 3}, NMVOC, TSP, PM{sub 10} and PM{sub 25} for Denmark. The emissions are projected to 2030 using basic scenarios together with the expected results of a few individual policy measures. Official Danish forecasts of activity rates are used in the models for those sectors for which the forecasts are available, i.e. the latest official forecast from the Danish Energy Agency. The emission factors refer either to international guidelines or are country-specific and refer to Danish legislation, Danish research reports or calculations based on emission data from a considerable number of plants. The projection models are based on the same structure and method as the Danish emission inventories in order to ensure consistency. (Author)

  4. Synthesis and characterization of F-doped Cs{sub 0.33}WO{sub 3−x}F{sub x} particles with improved near infrared shielding ability

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jingxiao; Luo, Jiayu; Shi, Fei, E-mail: shifei@dlpu.edu.cn; Liu, Suhua; Fan, Chuanyan; Xu, Qiang; Shao, Guolin

    2015-01-15

    F-doped Cs{sub 0.33}WO{sub 3−x}F{sub x} particles were successfully synthesized by the hydrothermal method with hydrofluoric acid as fluorine source, and a new kind of heat insulating films were prepared from dispersion of Cs{sub 0.33}WO{sub 3−x}F{sub x} nanoparticles in polyvinyl alcohol (PVA) aqueous solution. The effects of F doping on the crystal structure and morphology of Cs{sub 0.33}WO{sub 3−x}F{sub x} particles as well as the near-infrared (NIR) shielding ability and heat insulation properties of Cs{sub 0.33}WO{sub 3−x}F{sub x} films were investigated. The results indicated that HF acid addition could promote the formation of rod-like Cs{sub 0.33}WO{sub 3−x}F{sub x} particles during hydrothermal synthesis and increase the yield of Cs{sub 0.33}WO{sub 3−x}F{sub x} powders. Moreover, the as-prepared films from dispersion solution of Cs{sub 0.33}WO{sub 3−x}F{sub x} particles exhibited higher near-infrared (NIR) shielding ability and heat insulating properties than that of the undoped Cs{sub 0.33}WO{sub 3} film. Particularly, the as-prepared Cs{sub 0.33}WO{sub 3−x}F{sub x} sample with F/W (molar ratio)=0.45 showed best NIR shielding ability and transparent heat insulating performance. The formation mechanism of nanorod-like particles and the effects of F doping on the properties of Cs{sub 0.33}WO{sub 3−x}F{sub x} products were discussed. - Graphical abstract: F-doped Cs{sub 0.33}WO{sub 3−x}F{sub x} particles were successfully synthesized by the hydrothermal method with hydrofluoric acid as fluorine source. HF acid addition in the precursor solution could increase the yield of Cs{sub 0.33}WO{sub 3−x}F{sub x} powders and promote the formation of rod-like Cs{sub 0.33}WO{sub 3−x}F{sub x} particles. Moreover, the as-prepared Cs{sub 0.33}WO{sub 3−x}F{sub x} films from dispersion solution of Cs{sub 0.33}WO{sub 3−x}F{sub x} particles exhibited higher near-infrared (NIR) shielding ability and heat insulating properties than that of the undoped

  5. The influence of particle size and AgNO{sub 3} concentration in the ionic exchange process on the fungicidal action of antimicrobial glass

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, E.; Piletti, R. [Programa de Pos-Graduacao em Engenharia Quimica Universidade Federal de Santa Catarina - UFSC, Florianopolis, Santa Catarina (Brazil); Barichello, T. [Programa de Pos-Graduacao em Ciencias da Saude, Universidade do Extremo Sul Catarinense - UNESC, Criciuma, Santa Catarina (Brazil); Oliveira, C.M. [Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais, Universidade do Extremo Sul Catarinense - UNESC, Criciuma, Santa Catarina (Brazil); Kniess, C.T. [Programa de Mestrado Profissional em Administracao - Gestao de Projetos, Universidade Nove de Julho, Sao Paulo, Sao Paulo (Brazil); Angioletto, E. [Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais, Universidade do Extremo Sul Catarinense - UNESC, Criciuma, Santa Catarina (Brazil); Riella, H.G. [Programa de Pos-Graduacao em Engenharia Quimica Universidade Federal de Santa Catarina - UFSC, Florianopolis, Santa Catarina (Brazil); and others

    2012-08-01

    Antimicrobial materials have long been used as an effective means of reducing the risks posed to humans by fungi, bacteria and other microorganisms. These materials are essential in environments where cleanliness, comfort and hygiene are the predominate concerns. This work presents preliminary results for the development of a fungicidal vitreous material that is produced by the incorporation of a silver ionic specimen through ionic exchange reactions. Silver ions were incorporated into powdered glass via ionic exchange in an ionic medium containing silver species with different concentrations of AgNO{sub 3}. The fungicidal efficiency of the samples was studied as a function of the AgNO{sub 3} concentration and the particle size of the glass using the agar diffusion test for the microbiological analysis of the fungus species Candida albicans. The samples were examined by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The experimental results showed that the fungicidal effect was dependent on the AgNO{sub 3} concentration in the ionic exchange medium but was not dependent on the particle size of the glass. - Highlights: Black-Right-Pointing-Pointer The fungicidal powder glass presents high potential for application as polymeric additive and others application in the medical area. Black-Right-Pointing-Pointer The fungicidal effect was dependent on AgNO3 concentration, but was not dependent on the particle size of the glass. Black-Right-Pointing-Pointer The XRD results show that the ionic exchange process promotes the formation of silver crystalline phases with cubic cells.

  6. Influence of clay particles on Al{sub 2}O{sub 3} and TiO{sub 2} nanoparticles transport and retention through limestone porous media: measurements and mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Bayat, Ali Esfandyari, E-mail: ali.esfandiari.bayat@gmail.com; Junin, Radzuan [Universiti Teknologi Malaysia, Department of Petroleum Engineering, Faculty of Petroleum and Renewable Energy Engineering (Malaysia); Mohsin, Rahmat [Universiti Teknologi Malaysia, UTM-MPRC Institute for Oil and Gas, N29A, Lengkuk Suria (Malaysia); Hokmabadi, Mehrdad [Universiti Teknologi Malaysia, Department of Petroleum Engineering, Faculty of Petroleum and Renewable Energy Engineering (Malaysia); Shamshirband, Shahaboddin [University of Malaya, Department of Computer System and Information Technology, Faculty of Computer System and Information Technology (Malaysia)

    2015-05-15

    Utilization of nanoparticles (NPs) for a broad range of applications has caused considerable quantities of these materials to be released into the environment. Issues of how and where the NPs are distributed into the subsurface aquatic environments are questions for those in environmental engineering. This study investigated the influence of three abundant clay minerals namely kaolinite, montmorillonite, and illite in the subsurface natural aquatic systems on the transport and retention of aluminum oxide (Al{sub 2}O{sub 3}, 40 nm) and titanium dioxide (TiO{sub 2}, 10–30 nm) NPs through saturated limestone porous media. The clay concentrations in porous media were set at 2 and 4 vol% of the holder capacity. Breakthrough curves in the columns outlets were measured using a UV–Vis spectrophotometer. It was found that the maximum NPs recoveries were obtained when there was no clay particle in the porous medium. On the other hand, increase in concentration of clay particles has resulted in the NPs recoveries being significantly declined. Due to fibrous structure of illite, it was found to be more effective for NPs retention in comparison to montmorillonite and kaolinite. Overall, the position of clay particles in the porous media pores and their morphologies were found to be two main reasons for increase of NPs retention in porous media.

  7. Electrodeposition and electrochemical characterisation of thick and thin coatings of Sb and Sb/Sb{sub 2}O{sub 3} particles for Li-ion battery anodes

    Energy Technology Data Exchange (ETDEWEB)

    Bryngelsson, Hanna; Eskhult, Jonas; Edstroem, Kristina; Nyholm, Leif [Department of Materials Chemistry, The Aangstroem Laboratory, Uppsala University, P.O. Box 538, SE-751 21 Uppsala (Sweden)

    2007-12-20

    The possibilities to electrodeposit thick coatings composed of nanoparticles of Sb and Sb{sub 2}O{sub 3} for use as high-capacity anode materials in Li-ion batteries have been investigated. It is demonstrated that the stability of the coatings depends on their Sb{sub 2}O{sub 3} concentrations as well as microstructure. The electrodeposition reactions in electrolytes with different pH and buffer capacities were studied using chronopotentiometry and electrochemical quartz crystal microbalance measurements. The obtained deposits, which were characterised with XRD and SEM, were also tested as anode materials in Li-ion batteries. The influence of the pH and buffer capacity of the deposition solution on the composition and particle size of the deposits were studied and it is concluded that depositions from a poorly buffered solution of antimony-tartrate give rise to good anode materials due to the inclusion of precipitated Sb{sub 2}O{sub 3} nanoparticles in the Sb coatings. Depositions under conditions yielding pure Sb coatings give rise to deposits composed of large crystalline particles with poor anode stabilities. The presence of a plateau at about 0.8 V versus Li{sup +}/Li due to SEI forming reactions and the origin of another plateau at about 0.4 V versus Li{sup +}/Li seen during the lithiation of thin Sb coatings are also discussed. It is demonstrated that the 0.4 V plateau is present for Sb coatings for which the (0 1 2) peak is the main peak in the XRD diffractogram. (author)

  8. Cascades in model steels: The effect of cementite (Fe{sub 3}C) and Cr{sub 23}C{sub 6} particles on short-term crystal damage

    Energy Technology Data Exchange (ETDEWEB)

    Henriksson, K.O.E.

    2015-06-01

    Ferritic stainless steel can be modeled as an iron matrix containing precipitates of cementite (Fe{sub 3}C) and Cr{sub 23}C{sub 6}. When used in nuclear power production the steels in the vicinity of the core start to accumulate damage due to neutrons. The role of the afore-mentioned carbides in this process is not well understood. In order to clarify the situation bulk cascades created by primary recoils in model steels have been carried out in the present work. Investigated configurations consisted of bulk ferrite containing spherical particles (diameter of 4 nm) of either (1) Fe{sub 3}C or (2) Cr{sub 23}C{sub 6}. Primary recoils were initiated at different distances from the inclusions, with recoil energies varying between 100 eV and 1 keV. Results for the number of point defects such as vacancies and antisites are presented. These findings indicate that defects are also remaining when cascades are started outside the carbide inclusions. The work uses a recently developed Abell–Brenner–Tersoff potential for the Fe–Cr–C system.

  9. Thermal and magnetic behavior of Angustifolia Kunth bamboo fibers covered with Fe{sub 3}O{sub 4} particles

    Energy Technology Data Exchange (ETDEWEB)

    Calvo, S. [Laboratorio de Magnetismo y Materiales Avanzados, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Colombia, Sede Manizales, Manizales (Colombia); Arias, N.P. [Laboratorio de Materiales Nanoestructurados y Funcionales, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Colombia, Sede Manizales, Manizales (Colombia); Departamento de Ingenieria Electrica, Electronica y Computacion, Facultad de Ingenieria y Arquitectura, Universidad Nacional de Colombia, Sede Manizales, Manizales (Colombia); Giraldo, O., E-mail: ohggiraldo@hotmail.com [Laboratorio de Materiales Nanoestructurados y Funcionales, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Colombia, Sede Manizales, Manizales (Colombia); Rosales-Rivera, A.; Moscoso, O. [Laboratorio de Magnetismo y Materiales Avanzados, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Colombia, Sede Manizales, Manizales (Colombia)

    2012-08-15

    Several Angustifolia Kunth bamboo fibers, which have been previously treated with an alkaline solution, were coated with magnetite particles. The coating of the fibers was achieved by an in-situ co-precipitation method with Fe{sup 2+} and Fe{sup 3+}in NaOH or NH{sub 4}OH. The fibers were evaluated by chemical analysis using atomic absorption (A.A.) technique, structural characterization by X-ray diffraction (XRD), thermal stability with thermo-gravimetric analysis (TGA) in nitrogen at temperature range between 23 Degree-Sign C and 800 Degree-Sign C and magnetic behavior using vibrating sample magnetometry (VSM) applying a magnetic field between -27 KOe and 27 KOe at room temperature. We found that the thermal stability and magnetization depend of the synthesis method used to cover the Angustifolia Kunth bamboo fibers. In addition, an improved magnetic response was observed when NaOH solution is used to generate the magnetite coating on the fiber surface.

  10. A novel synthesis of SrCO{sub 3}–SrTiO{sub 3} nanocomposites with high photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Márquez-Herrera, A., E-mail: amarquez@ugto.mx [Universidad de Guanajuato, Departamento de Ingeniería Mecánica Agrícola, DICIVA, Campus Irapuato-Salamanca (Mexico); Ovando-Medina, Víctor M.; Castillo-Reyes, Blanca E. [Universidad Autónoma de San Luis Potosí, Ingeniería Química, COARA (Mexico); Meléndez-Lira, M. [CINVESTAV-IPN, Departamento de Física (Mexico); Zapata-Torres, M. [Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada (Mexico); Saldaña, N. [Universidad de Guanajuato, Departamento de Ingeniería Mecánica Agrícola, DICIVA, Campus Irapuato-Salamanca (Mexico)

    2014-12-15

    The results of the production and characterization of SrCO{sub 3}–SrTiO{sub 3} nanocomposites as a promising candidate for efficient photocatalysts are reported. The production is based on a novelty route employing the solvothermal method with strontium chloride and titanium (IV) butoxide as the precursor solutions. The effect on the properties of the nanocomposites due to changes in the content of SrCO{sub 3} and SrTiO{sub 3} is reported. The as-prepared materials were tested in the photodegradation of methylene blue dye in aqueous solutions under the solar light. The reported route allows the production of SrCO{sub 3}–SrTiO{sub 3} nanocomposites with particle sizes ranging between 18 and 29 nm. The SrCO{sub 3}–SrTiO{sub 3} nanocomposites obtained with 19 % of SrCO{sub 3} phase and 81 % of SrTiO{sub 3} (M10) can achieve 94 and 97 % of dye photodegradation after 30 and 120 min, respectively.

  11. Methods for determining particle size distribution and growth rates between 1 and 3 nm using the Particle Size Magnifier

    CERN Document Server

    Lehtipalo, Katrianne; Kontkanen, Jenni; Kangasluoma, Juha; Franchin, Alessandro; Wimmer, Daniela; Schobesberger, Siegfried; Junninen, Heikki; Petäjä, Tuukka; Sipilä, Mikko; Mikkilä, Jyri; Vanhanen, Joonas; Worsnop, Douglas R; Kulmala, Markku

    2014-01-01

    The most important parameters describing the atmospheric new particle formation process are the particle formation and growth rates. These together determine the amount of cloud condensation nuclei attributed to secondary particle formation. Due to difficulties in detecting small neutral particles, it has previously not been possible to derive these directly from measurements in the size range below about 3 nm. The Airmodus Particle Size Magnifier has been used at the SMEAR II station in Hyytiälä, southern Finland, and during nucleation experiments in the CLOUD chamber at CERN for measuring particles as small as about 1 nm in mobility diameter. We developed several methods to determine the particle size distribution and growth rates in the size range of 1–3 nm from these data sets. Here we introduce the appearance-time method for calculating initial growth rates. The validity of the method was tested by simulations with the Ion-UHMA aerosol dynamic model.

  12. Characterization investigations during mechanical alloying and sintering of Ni-W solid solution alloys dispersed with WC and Y{sub 2}O{sub 3} particles

    Energy Technology Data Exchange (ETDEWEB)

    Genc, Aziz, E-mail: agenc@itu.edu.t [Particulate Materials Laboratories, Department of Metallurgical and Materials Engineering, Istanbul Technical University, Maslak, 34469 Istanbul (Turkey); Luetfi Ovecoglu, M. [Particulate Materials Laboratories, Department of Metallurgical and Materials Engineering, Istanbul Technical University, Maslak, 34469 Istanbul (Turkey)

    2010-10-15

    Research highlights: {yields} Characterization investigations on the Ni-W solid solution alloys fabricated via mechanical alloying and the evolution of the properties of the powders with increasing MA durations. {yields} Reinforcement of the selected Ni-W powders with WC and Y{sub 2}O{sub 3} particles and further MA together for 12 h. {yields} There is no reported literature on the development and characterization of Ni-W solid solution alloys matrix composites fabricated via MA. {yields} Sintering of the developed composites and the characterization investigations of the sintered samples. {yields} Identification of new 'pomegranate-like' structures in the bulk of the samples. - Abstract: Blended elemental Ni-30 wt.% W powders were mechanically alloyed (MA'd) for 1 h, 3 h, 6 h, 12 h, 24 h, 36 h and 48 h in a Spex mixer/mill at room temperature in order to investigate the effects of MA duration on the solubility of W in Ni and the grain size, hardness and particle size. Microstructural and phase characterizations of the MA'd powders were carried out using X-ray diffractometer (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). On the basis of achieved saturation on the solid solubility, hardness and particle size, the Ni-30 wt.% W powders MA'd for 48 h were chosen as the matrix which was reinforced with different amounts of WC and/or with 1 wt.% Y{sub 2}O{sub 3} particles. The reinforced powders were further MA'd for 12 h. The MA'd powders were sintered at 1300 {sup o}C for 1 h under Ar and H{sub 2} gas flowing conditions. Microstructural characterizations of the sintered samples were conducted via XRD and SEM. Sintered densities were measured by using the Archimedes' method. Vickers microhardness tests were performed on both MA'd powders and the sintered samples. Sliding wear experiments were done in order to investigate wear behaviors of the sintered samples.

  13. Nanopowders M{sub 2}O{sub 3} (M = Y, La, Yb, Nd) with spherical particles and laser ceramics based on them

    Energy Technology Data Exchange (ETDEWEB)

    Bagayev, Sergei N; Kaminskii, Alexandr A; Kopylov, Yu L; Kravchenko, V B; Tolmachev, A V; Shemet, V V; Yavetskii, R P

    2013-03-31

    We have considered the problems of agglomeration of yttrium aluminium garnet (YAG) nanopowders prepared by chemical co-precipitation of precursors from aqueous solutions and subsequent calcination. To fabricate YAG and Y{sub 2}O{sub 3} laser ceramic samples with high optical transmittance and reproducible characteristics, we have developed a method for producing non-agglomerated nanopowders of pure and doped Y{sub 2}O{sub 3} by homogeneous chemical precipitation. Nanopowders Y{sub 2}O{sub 3} with La and Yb as well as mixtures of Y{sub 2}O{sub 3} : Nd and several commercial nanopowders of aluminium oxide have been compacted; optimised compacting technique have been selected; ceramic samples (Y, La, Yb){sub 2}O{sub 3} and YAG : Nd with high optical transmittance at a wavelength of 1 {mu}m have been produced by solid-phase synthesis. (extreme light fields and their applications)

  14. Thermoluminescence of LaAlO{sub 3}; Termoluminescencia de LaAlO{sub 3}:Dy

    Energy Technology Data Exchange (ETDEWEB)

    Morales H, A.; Zarate M, J. [Universidad Michoacana de San Nicolas de Hidalgo, Instituto de Investigacion en Metalurgia y Materiales, Ciudad Universitaria, Edif. U, 58060 Morelia, Michoacan (Mexico); Rivera M, T. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, 11500 Mexico D. F. (Mexico); Azorin N, J., E-mail: feyo_yo@hotmail.com [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (Mexico)

    2015-10-15

    In this paper the thermoluminescent properties of doped lanthanum aluminate (LaAlO{sub 3}) with dysprosium ion (Dy) were studied. The thermoluminescence characteristics in the samples were obtained using an ultraviolet radiation of 220 nm. The LaAlO{sub 3}:Dy samples were prepared by the modified Pechini method (Spray Dryer). The structural and morphological characterization was obtained by X-ray diffraction (XRD) and scanning electron microscopy (Sem) techniques respectively. The size particle composing the agglomerate was determined by Sem, agglomerated particles composed size of 2μm were observed. The thermoluminescence response of LaAlO{sub 3}:Dy was compared with that obtained with the undoped sample. Thermoluminescence brightness curves of LaAlO{sub 3}:Dy showed a peak centered at 185 grades C. Sensitivity of doped sample was greater, about 100 times compared with the undoped sample. Thermoluminescence response in function of the wavelength showed a maximum at 220 nm. Also the fading in thermoluminescence response was studied. (Author)

  15. Degradation mechanism of CH{sub 3}NH{sub 3}PbI{sub 3} perovskite materials upon exposure to humid air

    Energy Technology Data Exchange (ETDEWEB)

    Shirayama, Masaki; Kato, Masato; Fujiseki, Takemasa; Hara, Shota; Kadowaki, Hideyuki; Murata, Daisuke; Fujiwara, Hiroyuki, E-mail: fujiwara@gifu-u.ac.jp [Department of Electrical, Electronic and Computer Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193 (Japan); Miyadera, Tetsuhiko; Sugita, Takeshi; Chikamatsu, Masayuki [Research Center for Photovoltaics, National Institute of Advanced Industrial Science and Technology (AIST), Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8568 (Japan)

    2016-03-21

    Low stability of organic-inorganic perovskite (CH{sub 3}NH{sub 3}PbI{sub 3}) solar cells in humid air environments is a serious drawback which could limit practical application of this material severely. In this study, from real-time spectroscopic ellipsometry characterization, the degradation mechanism of ultra-smooth CH{sub 3}NH{sub 3}PbI{sub 3} layers prepared by a laser evaporation technique is studied. We present evidence that the CH{sub 3}NH{sub 3}PbI{sub 3} degradation in humid air proceeds by two competing reactions of (i) the PbI{sub 2} formation by the desorption of CH{sub 3}NH{sub 3}I species and (ii) the generation of a CH{sub 3}NH{sub 3}PbI{sub 3} hydrate phase by H{sub 2}O incorporation. In particular, rapid phase change occurs in the near-surface region and the CH{sub 3}NH{sub 3}PbI{sub 3} layer thickness reduces rapidly in the initial 1 h air exposure even at a low relative humidity of 40%. After the prolonged air exposure, the CH{sub 3}NH{sub 3}PbI{sub 3} layer is converted completely to hexagonal platelet PbI{sub 2}/hydrate crystals that have a distinct atomic-scale multilayer structure with a period of 0.65 ± 0.05 nm. We find that conventional x-ray diffraction and optical characterization in the visible region, used commonly in earlier works, are quite insensitive to the surface phase change. Based on results obtained in this work, we discuss the degradation mechanism of CH{sub 3}NH{sub 3}PbI{sub 3} in humid air.

  16. Sub 2 nm Particle Characterization in Systems with Aerosol Formation and Growth

    Science.gov (United States)

    Wang, Yang

    Aerosol science and technology enable continual advances in material synthesis and atmospheric pollutant control. Among these advances, one important frontier is characterizing the initial stages of particle formation by real time measurement of particles below 2 nm in size. Sub 2 nm particles play important roles by acting as seeds for particle growth, ultimately determining the final properties of the generated particles. Tailoring nanoparticle properties requires a thorough understanding and precise control of the particle formation processes, which in turn requires characterizing nanoparticle formation from the initial stages. The knowledge on particle formation in early stages can also be applied in quantum dot synthesis and material doping. This dissertation pursued two approaches in investigating incipient particle characterization in systems with aerosol formation and growth: (1) using a high-resolution differential mobility analyzer (DMA) to measure the size distributions of sub 2 nm particles generated from high-temperature aerosol reactors, and (2) analyzing the physical and chemical pathways of aerosol formation during combustion. Part. 1. Particle size distributions reveal important information about particle formation dynamics. DMAs are widely utilized to measure particle size distributions. However, our knowledge of the initial stages of particle formation is incomplete, due to the Brownian broadening effects in conventional DMAs. The first part of this dissertation studied the applicability of high-resolution DMAs in characterizing sub 2 nm particles generated from high-temperature aerosol reactors, including a flame aerosol reactor (FLAR) and a furnace aerosol reactor (FUAR). Comparison against a conventional DMA (Nano DMA, Model 3085, TSI Inc.) demonstrated that the increased sheath flow rates and shortened residence time indeed greatly suppressed the diffusion broadening effect in a high-resolution DMA (half mini type). The incipient particle

  17. A density functional theory study of the hydrates of NH{sub 3}{center_dot}H{sub 2}SO{sub 4} and its implications for the formation of new atmospheric particles

    Energy Technology Data Exchange (ETDEWEB)

    Ianni, J.C.; Bandy, A.R. [Drexel Univ., Philadelphia, PA (United States). Dept. of Chemistry

    1999-04-15

    The interest in tropospheric and stratospheric aerosols has risen in past years. This is primarily due to the fact that aerosols in the troposphere and stratosphere are altering the earth`s climate by scattering radiation directly or indirectly by changing the reflectivity of clouds. They have also been involved in indirectly depleting the Antarctic stratospheric ozone layer by converting relatively inert chlorine species to photochemically reactive species which are well-known ozone-destroying species. Density functional molecular orbital theory was used at the B3LYP/6-311++G(2d,2p)//B3LYP/6-311++G(2d,2p) level of theory to study the hydrates of NH{sub 3}{center_dot}H{sub 2}SO{sub 4}{center_dot}nH{sub 2}O for n = 0--5 and NH{sub 3}{center_dot}(H{sub 2}SO{sub 4}){sub 2}{center_dot}H{sub 2}O. Neutrals of the first four NH{sub 3}{center_dot}H{sub 2}SO{sub 4}{center_dot}nH{sub 2}O clusters (n = 0--4) spontaneously formed and were determined to be hydrogen-bonded molecular complexes of H{sub 2}SO{sub 4}, H{sub 2}O, and NH{sub 3}. Double ions (clusters containing a NH{sub 4}{sup +} cation and a HSO{sub 4}{sup {minus}} anion) spontaneously formed in clusters of NH{sub 3}{center_dot}{approximately}H{sub 2}SO{sub 4}{center_dot}nH{sub 2}O where n = 1--5. The energetics of the hydration and isomerization reactions also were calculated. Double ions are not energetically favorable until NH{sub 3}{center_dot}H{sub 2}SO{sub 4}{center_dot}4H{sub 2}O. The free energy of formation from free NH{sub 3} and H{sub 2}SO{sub 4}{center_dot}nH{sub 2}O had a maximum at n = 3 at room temperature with {Delta}G {approx} {minus}3 kcal/mol. NH{sub 3}{center_dot}(H{sub 2}SO{sub 4}){sub 2}{center_dot}H{sub 2}O was studied to see if NH{sub 3} can initiate new atmospheric particle growth. It has been shown that NH{sub 3} has no role in the initialization of new atmospheric particles.

  18. Effect of pH on particles size and gas sensing properties of In{sub 2}O{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Anand, Kanica, E-mail: kanica.anand@yahoo.com; Thangaraj, Rengasamy; Singh, Ravi Chand [Department of Physics, Guru Nanak Dev University, Amritsar 143005 (India)

    2016-05-23

    In this work, indium oxide (In{sub 2}O{sub 3}) nanoparticles have been synthesized by co-precipitation method and the effect of pH on the structural and sensor response values of In{sub 2}O{sub 3} nanoparticles has been reported. X-ray diffraction pattern (XRD) revealed the formation of cubic phase In{sub 2}O{sub 3} nanoparticles. FESEM results indicate the formation of nearly spherical shape In{sub 2}O{sub 3} nanoparticles. The band gap energy value changed with change in pH value and found to have highest value at pH 9. Indium oxide nanoparticles thus prepared were deposited as thick films on alumina substrates to act as gas sensors and their sensing response to ethanol vapors and LPG at 50 ppm was investigated at different operating temperatures. It has been observed that all sensors exhibited optimum response at 300°C towards ethanol and at 400°C towards LPG. In{sub 2}O{sub 3} nanoparticles prepared at pH 9, being smallest in size as compared to other, exhibit highest sensor response (SR).

  19. RapidNano: towards 20nm Particle Detection on EUV Mask Blanks

    NARCIS (Netherlands)

    Donck, J.C.J. van der; Bussink, P.G.W.; Fritz, E.C.; Walle, P. van der

    2016-01-01

    Cleanliness is a prerequisite for obtaining economically feasible yield levels in the semiconductor industry. For the next generation of lithographic equipment, EUV lithography, the size of yield-loss inducing particles for the masks will be smaller than 20 nm. Consequently, equipment for handling

  20. Chemical bath deposition of Cu{sub 3}BiS{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Deshmukh, S.G., E-mail: deshmukhpradyumn@gmail.com; Vipul, Kheraj, E-mail: vipulkheraj@gmail.com [Department of Applied Physics, Sardar Vallabhbhai National Institute of Technology, Ichchhanath, Surat (India); Panchal, A.K. [Department of Electrical Engineering, Sardar Vallabhbhai National Institute of Technology, Ichchhanath, Surat (India)

    2016-05-06

    First time, copper bismuth sulfide (Cu{sub 3}BiS{sub 3}) thin films were synthesized on the glass substrate using simple, low-cost chemical bath deposition (CBD) technique. The synthesized parameters such as temperature of bath, pH and concentration of precursors were optimized for the deposition of uniform, well adherent Cu{sub 3}BiS{sub 3} thin films. The optical, surface morphology and structural properties of the Cu{sub 3}BiS{sub 3} thin films were studied using UV-VIS-NIR spectra, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The as- synthesized Cu{sub 3}BiS{sub 3} film exhibits a direct band gap 1.56 to 1.58 eV having absorption coefficient of the order of 10{sup 5} cm{sup −1}. The XRD declares the amorphous nature of the films. SEM images shows films were composed of close-packed fine spherical nanoparticles of 70-80 nm in diameter. The chemical composition of the film was almost stoichiometric. The optical study indicates that the Cu{sub 3}BiS{sub 3} films can be applied as an absorber layer for thin film solar cells.

  1. Statistical evaluation of potential damage to the Al(OH){sub 3} layer on nTiO{sub 2} particles in the presence of swimming pool and seawater

    Energy Technology Data Exchange (ETDEWEB)

    Virkutyte, Jurate [Pegasus Technical Services, Inc (United States); Al-Abed, Souhail R., E-mail: al-abed.souhail@epa.gov [U.S. Environmental Protection Agency, National Risk Management Research Laboratory (United States)

    2012-03-15

    Nanosized TiO{sub 2} particles (nTiO{sub 2}) are usually coated with an Al(OH){sub 3} layer when used in sunscreen to shield against the harmful effects of free radicals that are generated when these particles are exposed to UV radiation. Therefore, it is vital to insure the structural stability of these particles in the environment where the protective layer may be damaged and adverse health and environmental effects can occur. This study utilized X-ray analysis (SEM-EDS) to provide a qualitative and semi-quantitative assessment of the chemical and physical characteristics of Al(OH){sub 3}-coated original and damaged nTiO{sub 2} particles (used in sunscreen lotion formulations) in the presence of both swimming pool and seawater. Also, by utilizing statistical tools, a distribution of Al/Ti (%) on the particle surface was determined and evaluated. It was found that 45 min of treatment with swimming pool and seawater significantly induced the redistribution of Al/Ti (%), which changed the surface characteristics of particles and, therefore, may have induced undesired photo-activity and the consequent formation of free radicals.

  2. Testicular biodistribution of 450 nm fluorescent latex particles after intramuscular injection in mice

    Science.gov (United States)

    Klein, Jean-Philippe; Boudard, Delphine; Cadusseau, Josette; Palle, Sabine; Forest, Valérie; Pourchez, Jérémie; Cottier, Michèle

    2013-01-01

    The significant expansion in the use of nanoparticles and submicron particles during the last 20 years has led to increasing concern about their potential toxicity to humans and particularly their impact on male fertility. Currently, an insufficient number of studies have focused on the testicular biodistribution of particles. The aim of our study was to assess the distribution of 450 nm fluorescent particles in mouse testes after intramuscular injection. To this end, testes were removed from 5 groups of 3 mice each at 1 h (H1), 4 days (D4), 21 days (D21), 45 days (D45) and 90 days (D90) after the injection of 7.28 × 109 particles in the tibialis anterior muscles of each mouse. We examined histological sections from these samples by epifluorescence microscopy and confocal microscopy and identified testicular biodistribution of a small number of particles in groups H1, D4, D21, D45 and D90. Using CD11b immunostaining, we showed that particles were not carried into the testis by macrophages. The intratesticular repartition of particles mainly followed testicular vascularization. Finally, we found some particles in seminiferous tubules but could not determine if the blood–testis barrier was crossed. PMID:23329290

  3. Sol–gel combustion synthesis, particle shape analysis and magnetic properties of hematite (α-Fe{sub 2}O{sub 3}) nanoparticles embedded in an amorphous silica matrix

    Energy Technology Data Exchange (ETDEWEB)

    Kopanja, Lazar [Faculty of Technology and Metallurgy, University of Belgrade, Belgrade (Serbia); Milosevic, Irena [Laboratoire CSPBAT, UMR 7244 CNRS Université Paris 13, 93017 Bobigny Cedex (France); Panjan, Matjaz [Jožef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia); Damnjanovic, Vesna [Department of Physics, University of Belgrade, Faculty of Mining and Geology, Belgrade (Serbia); Tadic, Marin, E-mail: marint@vinca.rs [Condensed Matter Physics Laboratory, Vinca Institute, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia)

    2016-01-30

    Graphical abstract: - Highlights: • Hematite nanoparticles are synthesized by using sol–gel combustion synthesis method. • The SQUID measurements show blocking temperature T{sub B} = 27 K and superparamagnetism. • TEM measurements show spherical particles and narrow size distribution. • The sample did not exhibit the Morin transition. • The magnetic moment μ{sub p} = 195 μ{sub B} and diameter d = 5 nm were determined. - Abstract: We report the synthesis and magnetic properties of hematite/amorphous silica nanostructures. Raman spectroscopy showed the formation of a hematite phase. A transmission electron microscopy (TEM) revealed spherically shaped hematite nanoparticles, well-dispersed in an amorphous silica matrix. In order to quantitatively describe morphological properties of nanoparticles, we use the circularity of shapes as a measure of how circular a shape is. Diameters of about 5 nm and a narrow size distribution of nanoparticles are observed. The obtained hematite nanoparticles exhibit superparamagnetic properties at room temperature (SPION). The sample does not display the Morin transition. The FC hysteresis loop at 5 K has shown an exchange bias effect. These results have been compared to those previously reported for α-Fe{sub 2}O{sub 3}/SiO{sub 2} nanosystems in the literature. These comparisons reveal that the sol–gel combustion method yields hematite nanoparticles with a higher magnetization and magnetic moment. These data indicate the existence of an additional factor that contributes to magnetization. We suggest that the increased magnetization is due to an increased number of the surface spins caused by the breaking of large numbers of exchange bonds between surface atoms (disordered structure). This leads to an increase in the magnetic moment per a hematite nanoparticle and an exchange bias effect. We have concluded that the combustion-related part of this synthesis method enhances surface effects, i.e. it promotes the breaking of

  4. Preparation and antibacterial activity of Fe{sub 3}O{sub 4}-Ag nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Gong Ping [State Key Laboratory of Chemo/Biosensing and Chemometrics, Biomedical Engineering Centre, College of Chemistry and Chemical Engineering, Hunan University, Research Centre for Bio-Nanotechnology Engineering of Hunan Province, Changsha 410082 (China); Li Huimin [Biomedical Engineering Center, College of Material Science and Technology, Hunan University, Changsha, 410082 (China); He Xiaoxiao [State Key Laboratory of Chemo/Biosensing and Chemometrics, Biomedical Engineering Centre, College of Chemistry and Chemical Engineering, Hunan University, Research Centre for Bio-Nanotechnology Engineering of Hunan Province, Changsha 410082 (China)] (and others)

    2007-07-18

    Bifunctional Fe{sub 3}O{sub 4}-Ag nanoparticles with both superparamagnetic and antibacterial properties were prepared by reducing silver nitrate on the surface of Fe{sub 3}O{sub 4} nanoparticles using the water-in-oil microemulsion method. Formation of well-dispersed nanoparticles with sizes of 60 {+-} 20 nm was confirmed by transmission electron microscopy and dynamic light scattering. X-ray diffraction patterns and UV-visible spectroscopy indicated that both Fe{sub 3}O{sub 4} and silver are present in the same particle. The superparamagnetism of Fe{sub 3}O{sub 4}-Ag nanoparticles was confirmed with a vibrating sample magnetometer. Their antibacterial activity was evaluated by means of minimum inhibitory concentration value, flow cytometry, and antibacterial rate assays. The results showed that Fe{sub 3}O{sub 4}-Ag nanoparticles presented good antibacterial performance against Escherichia coli (gram-negative bacteria), Staphylococcus epidermidis (gram-positive bacteria) and Bacillus subtilis (spore bacteria). Furthermore, Fe{sub 3}O{sub 4}-Ag nanoparticles can be easily removed from water by using a magnetic field to avoid contamination of surroundings. Reclaimed Fe{sub 3}O{sub 4}-Ag nanoparticles can still have antibacterial capability and can be reused.

  5. Projection of SO{sub 2}, NO{sub X}, NMVOC, NH{sub 3} and particle emissions - 2005 to 2030

    Energy Technology Data Exchange (ETDEWEB)

    Boll Illerup, J.; Nielsen, Ole-Kenneth; Winther, M.; Hjorth Mikkelsen, M.; Nielsen, Malene; Fauser, P.; Gyldenkaerne, S.

    2008-05-15

    This report contains a description of models and background data for projection of SO{sub 2}, NO{sub X}, NH{sub 3}, NMVOC, TSP, PM{sub 10} and PM{sub 2.5} for Denmark. The emissions are projected to 2030 using basic scenarios together with the expected results of a few individual policy measures. Official Danish forecasts of activity rates are used in the models for those sectors for which the forecasts are available, i.e. the latest official forecast from the Danish Energy Authority. The emission factors refer to international guidelines and some are country-specific and refer to Danish legislation, Danish research reports or calculations based on emission data from a considerable number of plants. The projection models are based on the same structure and method as the Danish emission inventories in order to ensure consistency. (au)

  6. Influence of surface functionalization on structural and photo-luminescence properties of CeF{sub 3}:Tb nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ansari, Anees A., E-mail: aneesaansari@gmail.com

    2017-07-01

    Graphical abstract: We designed highly aqueous dispersible CeF{sub 3}:Tb@LaF{sub 3}@SiO{sub 2} nanoparticles. The epitaxial growth of inert LaF{sub 3} shell and further amorphous silica, respectively, enhanced their optical and luminescence properties, which is highly usable for luminescent biolabeling, and optical bio-probe etc. - Abstract: Highly luminescent and aqueous soluble CeF{sub 3}:Tb (core),CeF{sub 3}:Tb@LaF{sub 3}(core/shell) and CeF{sub 3}:Tb@LaF{sub 3}@ SiO{sub 2} (core/shell/Si) nanoparticles(NPs) with mean particle size 12 nm were prepared by co-precipitation method at low temperature. X-ray diffraction pattern verified the phase purity, high crystallinity of hexagonal structure. The TEM image and SAED pattern revealed the single phase polycrystalline nature, well-dispersed irregular shaped hexagonal structure. FTIR spectra show the characteristic infrared peaks of silica, it suggests the successful silica surface coating around the core/shell NPs. The excitation and emission intensity of core/shell NPs were remarkably increased then their counterpart core NPs. It implies that a significant amount of nonradiative transition centers existing on the surface of core NPs has been eliminated due to the formation of passivated LaF{sub 3} layer. The silica surface modification over the core/shell NPs strikingly enhanced the solubility character in an aqueous environment.

  7. Enhanced thermoelectric properties in p-type Bi{sub 0.4}Sb{sub 1.6}Te{sub 3} alloy by combining incorporation and doping using multi-scale CuAlO{sub 2} particles

    Energy Technology Data Exchange (ETDEWEB)

    Song, Zijun; Liu, Yuan; Zhou, Zhenxing; Lu, Xiaofang; Wang, Lianjun [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai (China); Institute of Functional Materials, Donghua University, Shanghai (China); Zhang, Qihao [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai (China); University of Chinese Academy of Sciences, Beijing (China); Jiang, Wan [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai (China); Institute of Functional Materials, Donghua University, Shanghai (China); School of Material Science and Engineering, Jingdezhen Ceramic Institute, Jingdezhen (China); Chen, Lidong [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai (China)

    2017-01-15

    Multi-scale CuAlO{sub 2} particles are introduced into the Bi{sub 0.4}Sb{sub 1.6}Te{sub 3} matrix to synergistically optimize the electrical conductivity, Seebeck coefficient, and the lattice thermal conductivity. Cu element originating from fine CuAlO{sub 2} grains diffuses into the Bi{sub 0.4}Sb{sub 1.6}Te{sub 3} matrix and tunes the carrier concentration while the coarse CuAlO{sub 2} particles survive as the second phase within the matrix. The power factor is improved at the whole temperatures range due to the low-energy electron filtering effect on Seebeck coefficient and enhanced electrical transport property by mild Cu doping. Meanwhile, the remaining CuAlO{sub 2} inclusions give rise to more boundaries and newly built interfaces scattering of heat-carrying phonons, resulting in the reduced lattice thermal conductivity. Consequently, the maximum ZT is found to be enhanced by 150% arising from the multi-scale microstructure regulation when the CuAlO{sub 2} content reaches 0.6 vol.%. Not only that, but the ZT curves get flat in the whole temperature range after introducing the multi-scale CuAlO{sub 2} particles, which leads to a remarkable increase in the average ZT. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. The effect of surface modification on Eu{sup 3+} luminescence in EuF{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Safronikhin, Anatoly, E-mail: safronikhin@yandex.ru; Ehrlich, Heinrich; Kuzmina, Natalia; Lisichkin, Georgy

    2014-07-01

    Reaction between Eu(NO{sub 3}){sub 3} and NH{sub 4}F in aqueous media was applied to produce EuF{sub 3} doughnut-like aggregates with a diameter of 200–500 nm and thickness of 50–150 nm composed of nanoparticles with a mean diameter of 16 nm. The impregnation, sorption and mechanochemical treatment were used for surface modification of EuF{sub 3} doughnut-like particles with 1,10-phenanthroline and sodium dibenzoylmethanate which are sensitizing ligands for Eu{sup 3+} luminescence. The data of transmission electron microscopy, elemental analysis, Fourier transform infrared spectroscopy, and luminescence spectroscopy have proved that the organic ligands are coordinated to surface Eu{sup 3+} ions, forming surface complexes. The surface modification of the EuF{sub 3} nanoparticles with sodium dibenzoylmethanate and 1,10-phenanthroline leads to increase in the luminescence intensity at 612 nm ({sup 5}D{sub 0} → {sup 7}F{sub 2} transition) in comparison with the luminescence intensity of the unmodified EuF{sub 3} nanoparticles. Energy transfer from the ligand to Eu{sup 3+} ion in the surface complexes makes a main contribution to this effect.

  9. Particle control challenges in process chemicals and ultra-pure water for sub-10nm technology nodes

    Science.gov (United States)

    Rastegar, Abbas; Samayoa, Martin; House, Matthew; Kurtuldu, Hüseyin; Eah, Sang-Kee; Morse, Lauren; Harris-Jones, Jenah

    2014-04-01

    Particle contamination in ultra-pure water (UPW) and chemicals will eventually end up on the surface of a wafer and may result in killer defects. To improve the semiconductor processing yield in sub-10 nm half pitch nodes, it is necessary to control particle defectivity. In a systematic study of all major techniques for particle detection, counting, and sizing in solutions, we have shown that there is a gap in the required particle metrology which needs to be addressed by the industry. To reduce particles in solutions and improve filter retention for sub-10 nm particles with very low densities (<10 particles/mL), liquid particle counters that are able to detect small particles at low densities are required. Non-volatile residues in chemicals and UPW can result in nanoparticles. Measuring absolute non-volatile residues in UPW with concentrations in the ppb range is a challenge. However, by using energy-dispersive spectroscopy (EDS) analysis through transmission electron microscopy (TEM) of non-volatile residues we found silica both in dissolved and colloidal particle form which is present in one of the cleanest UPW that we tested. A particle capture/release technique was developed at SEMATECH which is able to collect particles from UPW and release them in a controlled manner. Using this system we showed sub-10 nm particles are present in UPW. In addition to colloidal silica, agglomerated carbon containing particles were also found in UPW.

  10. Thermal morphological evolution of platinum nano-particles in Pt-Al{sub 2}O{sub 3} nano-composites

    Energy Technology Data Exchange (ETDEWEB)

    Maaza, M. [Nanosciences Laboratories, Solid State Materials Group, iTHEMBA LABS, PO Box 722, Somerset West 7129, Faure (South Africa)]. E-mail: maaza@tlabs.ac.za; Nemraoui, O. [Physics Department, Rand Afrikaans University, Auckland Park, PO Box 392, Johannesburg (South Africa); Sella, C. [Laboratoire d' Optique des Solides, Universite Pierre-Marie Curie, Paris VI (France); Lafait, J. [Laboratoire d' Optique des Solides, Universite Pierre-Marie Curie, Paris VI (France); Gibaud, A. [Laboratoire Surface and Interface, Universite du Maine, Le Mans (France); Pischedda, V. [High Pressure-High Temperature Group, University of the Witwatersrand-Johannesburg, Wits 2050, Johannesburg (South Africa)

    2005-08-29

    Temperature morphological evolution of nonpercolated granular nano-structures of platinum nano-particles embedded in an insulating alumina matrix was investigated by X-rays scattering in grazing angle reflection mode. In the investigated temperature range of 298-823 K, it was found that the annealing treatment tends to increase the Pt nano-particles' size and to produce a quasi-mono-disperse Pt nano-particles followed by a reduction of the barrier thickness between them. The percolation temperature is estimated to be of the order of 890 K. Using the rate constant governing the growth of the Pt nano-particles, the corresponding activation energy was determined to be about 90 kJ/mol.

  11. A distinct atomic structure-catalytic activity relationship in 3-10 nm supported Au particles.

    Science.gov (United States)

    Petkov, Valeri; Ren, Yang; Shan, Shiyao; Luo, Jin; Zhong, Chuan-Jian

    2014-01-07

    Bulk Au is very inert but Au nanoparticles less than 5 nm in size have been found to be catalytically active for several reactions, in particular for low-temperature oxidation of CO. Using high-energy X-ray diffraction coupled with atomic pair distribution function analysis and computer simulations we determine the structure of 3 nm and 10 nm Au particles supported on titania and silica as typical representatives of reducible and irreducible supports, respectively. We find that the synthesis protocol adopted in our work affects strongly and differently the structure of the Au nanoparticles on the different supports. This leads to clearly distinct dependences of the catalytic activity of the nanoparticles on their size. In the case of the silica support the catalytic activity of Au nanoparticles increases and in the case of the titania support it decreases with decreasing nanoparticle size. The experimental results are considered in terms of current theoretical predictions and found to be in good accord with them.

  12. Structural and magnetic characterization of a porous silicon/Fe{sub 3}O{sub 4} composite

    Energy Technology Data Exchange (ETDEWEB)

    Granitzer, Petra; Rumpf, Klemens [Institute of Physics, Karl-Franzens-University Graz, Universitaetsplatz 5, 8010 Graz (Austria); Venkatesan, Munuswamy [Institute of Physics, Trinity College Dublin, College Green, Dublin 2 (Ireland); Cabrera, Lourisa; Roca, Alejandro; Morales, Puerto [Instituto de Ciencia de Materiales Madrid, CSIC, Sor Juana Ines de la Cruz 3, Cantoblanco, 28049 Madrid (Spain); Poelt, Peter; Albu, Mihaela [Institute for Electron Microscopy, University of Technology Graz, Steyrergasse 17, 8010 Graz (Austria)

    2011-06-15

    Magnetite nanoparticles are infiltrated into porous silicon leading to an accumulation of the particles within the pores. The minimum distance between the Fe{sub 3}O{sub 4}-particles is given by the coating of the particles which is in the range of a few nanometers. Due to the coating exchange coupling between the particles is excluded, whereas dipolar coupling can take place. The distance between the pores is about 45 nm which assures that the magnetic particle-particle interaction within individual pores is stronger than between particles of adjacent pores. Thus the morphology of the porous silicon matrix influences the magnetic behaviour of the composite. Furthermore the transition between ferromagnetic behaviour (low temperatures) and superparamagnetic behaviour (higher temperatures) of the specimens is figured out by investigating samples with two different sizes of infiltrated Fe{sub 3}O{sub 4} nanoparticles. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. Getting nanometric MoO{sub 3} through chemical synthesis and high energy milling

    Energy Technology Data Exchange (ETDEWEB)

    Santos-Beltrán, M. [Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología, Miguel de Cervantes No. 120, C.P. 31136 Chihuahua, Chih. (Mexico); Paraguay-Delgado, F., E-mail: francisco.paraguay@cimav.edu.mx [Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología, Miguel de Cervantes No. 120, C.P. 31136 Chihuahua, Chih. (Mexico); Santos-Beltrán, A. [Universidad Tecnológica de Chihuahua Sur, Km. 3 Carretera Chihuahua a Aldama s/n, C.P. 31050 Chihuahua, Chih. (Mexico); Fuentes, L. [Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología, Miguel de Cervantes No. 120, C.P. 31136 Chihuahua, Chih. (Mexico)

    2015-11-05

    The effects of high energy mechanical milling (HEMM) were studied on the microstructure and optical properties of MoO{sub 3} for hexagonal and orthorhombic phases. Employing HEMM was possible change particle size as a function of mechanical milling time, as well as the small quantity transformation percentage from hexagonal to orthorhombic phase. The relationship between microstrain and optical properties generated was studied. The electronic structures were calculated using the Density Functional Theory (DFT); to determinate partial density of state (PDOS). Band gap structure calculations show a good correlation between experimental and simulated data. The approximated values of microstrain, particle size, lattice parameters and oxygen vacancies were obtained employing the Rietveld refinement of X-ray diffraction patterns. Samples were characterized by electron microscopy techniques, surface area analysis (BET), thermal-gravimetric analysis (TGA), differential scanning calorimetry (DSC) and ultraviolet–visible spectroscopy (UV–Vis). It was possible, obtain particles with size below 40 nm by 30 min milling. - Graphical abstract: Orthorhombic phase, SEM image, SAED before milling, milling NPs, Particle size and band gap variation by milling time. - Highlights: • MoO{sub 3} with hexagonal and orthorhombic structures was synthesized selectively. • By milling short time (30 m), it was possible get 40 nm diameter particles. • The band gap decrease for nanoparticles, then corroborated by simulation. • MoO{sub 3} nanoparticles get high surface area for new technologic applications.

  14. Green tide deactivation with layered-structure cuboids of Ag/CaTiO{sub 3} under UV light

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Soo-Wohn [Global Research Laboratory, Sun Moon University, Galsan-Ri, Tangjung-Myon, Asan Chungnam 336-708 (Korea, Republic of); Lozano-Sánchez, L.M. [División de Materiales Avanzados, Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa San José 2055 Col. Lomas 4a sección, C.P. 78216 San Luis Potosí, S.L.P. (Mexico); Rodríguez-González, V., E-mail: vicente.rdz@ipicyt.edu.mx [División de Materiales Avanzados, Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa San José 2055 Col. Lomas 4a sección, C.P. 78216 San Luis Potosí, S.L.P. (Mexico)

    2013-12-15

    Graphical abstract: Synergic reasons such as mass transfer, morphology, biocide properties, UV-A photoresponse, and electron trapping that reduce recombination on Ag/CaTiO{sub 3} nanocomposites, have the potential for the generation of reactive radicals that promote the fatal irreversible deactivation of Tetraselmis suecica algae in 12 min under UV-A irradiation. -- Highlights: • An alternative to deactivate harmful green tide is proposed by employing Ag/CaTiO{sub 3}. • Particles of perovskite-like have rectangular prisms morphology with AgNPs ∼13 nm. • The cuboids achieve complete inactivation of Tetraselmis suecica algae in 12 min. • AgNPs functionalization induce fatal irreversible damages on the algae surface. -- Abstract: In this work, an alternative to deactivate noxious green tide Tetraselmis suecica in the short-term is proposed by employing Perovskite-like cube-shaped, crystalline CaTiO{sub 3} semiconductors functionalized with atomic silver nanoparticles. CaTiO{sub 3} was prepared by a microwave-assisted hydrothermal method and then Ag{sup 0}NPs (1 wt% of CaTiO{sub 3}), were added by the photoreduction method. The XRD results show that crystalline CaTiO{sub 3} has an orthorhombic unit cell with a Perovskite-like structure. Images obtained by FESEM and HRTEM microscopies show well-faceted CaTiO{sub 3} rectangular prismatic morphology functionalizated with silver nanoparticles ∼13.5 nm. XPS and EDS-FESEM has confirmed the composition of CaTiO{sub 3} and silver occurring mainly as reduced metal. The UV inactivation of noxious T. suecica with Ag/CaTiO{sub 3} nanocomposites formed on bare materials results in complete deactivation of the algae in 12 min. The direct contact between harmful algae and Ag/CaTiO{sub 3} nanocomposite is necessary to deactivate the algae and inhibits algae viability.

  15. Novel method of room temperature ionic liquid assisted Fe{sub 3}O{sub 4} nanocubes and nanoflakes synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Ramalakshmi, M. [Sustainable Energy and Smart Materials Lab., Department of Nanoscience and Technology, Alagappa University, Karaikudi 630 002, Tamilnadu (India); Department of Industrial Chemistry, Alagappa University, Karaikudi India (India); Shakkthivel, P., E-mail: apsakthivel@yahoo.com [Sustainable Energy and Smart Materials Lab., Department of Nanoscience and Technology, Alagappa University, Karaikudi 630 002, Tamilnadu (India); Sundrarajan, M. [Department of Industrial Chemistry, Alagappa University, Karaikudi India (India); Chen, S.M. [Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei, Taiwan (China)

    2013-08-01

    Graphical abstract: - Highlights: • First time [Bmim][TfO] IL is used for the Fe{sub 3}O{sub 4} nanoparticle synthesis. • Novel method tunes Fe{sub 3}O{sub 4} nanocubes and nanoflakes forms influenced by the base and IL. • Fe{sub 3}O{sub 4} oxidized topotactically into γ-Fe{sub 2}O{sub 3} nanoparticles by annealing and base. • Uniform morphology with average size of 33 nm negligible superstructure are formed. • Ms values are characterized by thin layer of γ-Fe{sub 2}O{sub 3} on the nanoparticle surface. - Abstract: For the first time, the nanomagnetite superparamagnetic particles are successfully synthesized by precipitation method using 1-n-butyl-3-methylimidazolium trifluoromethane sulfonate [Bmim][TfO] ionic liquid medium/surfactant. The obtained Fe{sub 3}O{sub 4} particles are nanocubes and nanoflakes and this formation is influenced by the base concentration and anisotropic circumstances produced by the ionic liquid and their size varies from 20 nm to 150 × 300 nm (width × length). The synthesized magnetite nanoparticles are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, Field emission scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM) and Vibrating sample magnetometer (VSM) studies. The results show that the core of the Fe{sub 3}O{sub 4} nanoparticles is surrounded by a thin layer of γ-Fe{sub 2}O{sub 3} by topotactical partial oxidation, which is remarkably proceed with the subsequent calcination. The magnetite nanocubes have high saturation magnetization value and exhibit superparamagnetic hysteresis loop.

  16. An ABCA1-independent pathway for recycling a poorly lipidated 8.1 nm apolipoprotein E particle from glia

    Science.gov (United States)

    Fan, Jianjia; Stukas, Sophie; Wong, Charmaine; Chan, Jennifer; May, Sharon; DeValle, Nicole; Hirsch-Reinshagen, Veronica; Wilkinson, Anna; Oda, Michael N.; Wellington, Cheryl L.

    2011-01-01

    Lipid transport in the brain is coordinated by glial-derived lipoproteins that contain apolipoprotein E (apoE) as their primary protein. Here we show that apoE is secreted from wild-type (WT) primary murine mixed glia as nascent lipoprotein subspecies ranging from 7.5 to 17 nm in diameter. Negative-staining electron microscropy (EM) revealed rouleaux, suggesting a discoidal structure. Potassium bromide (KBr) density gradient ultracentrifugation showed that all subspecies, except an 8.1 nm particle, were lipidated. Glia lacking the cholesterol transporter ABCA1 secreted only 8.1 nm particles, which were poorly lipidated and nondiscoidal but could accept lipids to form the full repertoire of WT apoE particles. Receptor-associated-protein (RAP)-mediated inhibition of apoE receptor function blocked appearance of the 8.1 nm species, suggesting that this particle may arise through apoE recycling. Selective deletion of the LDL receptor (LDLR) reduced the level of 8.1 nm particle production by approximately 90%, suggesting that apoE is preferentially recycled through the LDLR. Finally, apoA-I stimulated secretion of 8.1 nm particles in a dose-dependent manner. These results suggest that nascent glial apoE lipoproteins are secreted through multiple pathways and that a greater understanding of these mechanisms may be relevant to several neurological disorders. PMID:21705806

  17. Magnetic and dielectric properties of HoMnO{sub 3} nanoparticles synthesized by the polymerized complex method

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xianguo, E-mail: liuxianguohugh@gmail.com [School of Materials Science and Engineering, Anhui University of technology, Ma' anshan, Anhui 243002 (China); Department of Electrical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Or, Siu Wing, E-mail: eeswor@polyu.edu.hk [Department of Electrical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Sun, Yuping [Center for Engineering practice and Innovation Education, Anhui University of technology, Ma' anshan, Anhui 243002 (China); Jin, Chuangui; Lv, Yaohui [School of Materials Science and Engineering, Anhui University of technology, Ma' anshan, Anhui 243002 (China); Wu, Yuxi [Institute of Molecular Engineering and Applied Chemistry, Anhui University of Technology, Ma' anshan, Anhui 243002 (China)

    2013-06-15

    In this paper, we report on the magnetic and dielectric properties of HoMnO{sub 3} nanoparticles with different size synthesized by a polymerized complex method have been investigated. The HoMnO{sub 3} nanoparticles crystallized in hexagonal perovskite-type structure. The zero-field-cooled magnetic susceptibility curve of HoMnO{sub 3} nanoparticles with averaged size of 30 nm shows that complicated magnetic transitions occurred in a temperature range from 2 to 100 K, which was confirmed by magnetic hysteresis loops. With increasing the particle size, the antiferromagnetic (AFM) transition temperature increases from 56 to 77 K, due to the reduced surface-to-volume ratio. Moreover, with a decrease in particle size, the Mn-spin reorientation temperature (T{sub SR}) is enhanced from 44 to 48 K. - Highlights: • HoMnO{sub 3} nanoparticles have been synthesized by a polymerized complex method. • The magnetic properties of HoMnO{sub 3} nanoparticles have been investigated. • The dielectric properties of HoMnO{sub 3} nanoparticles have been investigated. • The antiferromagnetic transition temperature increases with the particle size.

  18. Effect of the La(OH){sub 3} preparation method on the surface and rehydroxylation properties of resulting La{sub 2}O{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Mendez, M. [Univ. Rovira i Virgili (URV), Departament de Quimica Fisica i Inorganica, Centre EmaS (Spain); Carvajal, J. J. [Univ. Rovira i Virgili (URV), Fisica i Cristallografia de Materials i Nanomaterials (FICMA-FiCNA), Centre EmaS (Spain); Marsal, L. F. [Univ. Rovira i Virgili (URV), Departament d' Enginyeria Electronica, Centre EmaS (Spain); Salagre, P. [Univ. Rovira i Virgili (URV), Departament de Quimica Fisica i Inorganica, Centre EmaS (Spain); Aguilo, M.; Diaz, F. [Univ. Rovira i Virgili (URV), Fisica i Cristallografia de Materials i Nanomaterials (FICMA-FiCNA), Centre EmaS (Spain); Formentin, P.; Pallares, J. [Univ. Rovira i Virgili (URV), Departament d' Enginyeria Electronica, Centre EmaS (Spain); Cesteros, Y., E-mail: yolanda.cesteros@urv.cat [Univ. Rovira i Virgili (URV), Departament de Quimica Fisica i Inorganica, Centre EmaS (Spain)

    2013-03-15

    Several lanthanum hydroxides (28-146 m{sup 2}/g) were prepared by different procedures involving precipitation and hydrothermal methods by conventional heating or with microwaves. The use of ultrasounds during precipitation led to the formation of additional crystalline phases whereas the aging treatment with microwaves decreased the temperature needed to form the lanthanum oxide phase when compared with the samples aged by conventional heating. After calcination, La{sub 2}O{sub 3} samples showed similar BET surface areas (3-5 m{sup 2}/g) but different particle sizes ranging from 150 to 600 nm depending on the La(OH){sub 3} preparation method, as observed by TEM. La{sub 2}O{sub 3} samples were completely rehydroxylated after 80 h of exposure to atmospheric air at controlled humidity conditions recovering only partially the surface areas of the La(OH){sub 3} precursors (14-18 m{sup 2}/g). The progress of rehydroxylation with time occurred in several steps at different rates. Rehydroxylation rate mainly depended on the particle size and surface area of the lanthanum oxide sample. Therefore, the method used to prepare the initial lanthanum hydroxide affects the surface and rehydroxylation properties of the subsequent lanthanum oxide sample.

  19. Experimental and simulated scattering matrices of small calcite particles at 647nm

    Science.gov (United States)

    Dabrowska, D. D.; Muñoz, O.; Moreno, F.; Nousiainen, T.; Zubko, E.; Marra, A. C.

    2013-07-01

    We present measurements of the complete scattering matrix as a function of the scattering angle of a sample of calcite particles. The measurements are performed at 647nm in the scattering angle range from 3° to 177°. To facilitate the use of the experimental data we present a synthetic scattering matrix based on the measurements and defined in the full range from 0° to 180°. The scattering matrix of the calcite sample is modeled using the discrete-dipole approximation. Two sets of shapes, flake-like and rhomboid-like particles giving a total of 15 different targets are considered since both types of shapes have been found in our calcite sample. In our computations we use the measured size distribution of the calcite sample truncated at 1.2μm. We present a theoretical study of the impact of birefringence on the computed scattering matrix elements for both sets of shapes. Four different cases regarding the composition of the calcite particles are considered: two isotropic cases corresponding to the ordinary and extraordinary refractive index of calcite, respectively; one equivalent isotropic case analogous to internal mixing; and birefringence fully accounted for. Numerical simulations are compared with the experimental data. We find that birefringence has little impact on the calculated phase functions but it has a significant effect on the polarization-related elements of the scattering matrix. Moreover, we conclude that the shape of the targets (flakes or irregular rhomboids) has a much stronger effect on the computed scattering matrix elements than birefringence.

  20. Rapid preparation of ultrafine BaSO{sub 3} by SO{sub 2} storage material

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Fei; Sha, Feng; Qiao, Xian Shu; Zhao, Tian Xiang; Guo, Bo; Zhang, Jian Bin [College of Chemical Engineering, Inner Mongolia University of Technology, Huhhot (Korea, Republic of)

    2017-01-15

    In this work, a green and efficient process was developed for the preparation of ultrafine BaSO{sub 3} with layered nanostructure surface via the reaction of BaCl{sub 2} with a SO{sub 2} storage material (SO{sub 2}SM) at room temperature. The absorption of SO{sub 2} with equimolar ethylenediamine (EDA) and ethylene glycol (EG) afforded SO{sub 2}SM, which not only offered alkyl sulfite but also released EDA and EG that served as efficient surfactants to promote the formation of BaSO{sub 3} with spherical morphology and porous structure in the process of synthesis of ultrafine BaSO{sub 3}. The factors affecting the morphology and size of BaSO{sub 3} particle were assessed by investigating the effects of SO{sub 2}SM concentration, BaCl{sub 2} concentration, stirring time and speed. It was found that a higher SO{sub 2}SM concentration led to a higher degree of supersaturation, and the particle size of BaSO{sub 3} could be reduced by increasing SO{sub 2}SM concentration. Moreover, under the identified optimal reaction conditions, ultrafine BaSO{sub 3} was obtained with an average diameter of 450 nm. In addition, a plausible formation process of BaSO{sub 3} was proposed to explain the observed reaction results. Overall, the developed process in this work provides an efficient method for the capture, utilization, and conversion of SO{sub 2} into a valuable chemical.

  1. A facial one-pot route synthesis and characterization of Y-stabilized Sb{sub 2}O{sub 3} solar reflective thermal insulating coatings

    Energy Technology Data Exchange (ETDEWEB)

    Wang Zhengjun [Department of Chemistry, Shanghai Normal University, Shanghai 200234 (China); Liu Jie, E-mail: liujie@shnu.edu.cn [Department of Chemistry, Shanghai Normal University, Shanghai 200234 (China); Wang Feijiu [Department of Chemistry, Shanghai Normal University, Shanghai 200234 (China); Yu Xibin, E-mail: xibinyu@shnu.edu.cn [Department of Chemistry, Shanghai Normal University, Shanghai 200234 (China)

    2011-10-17

    Highlights: {yields} Sb{sub 2}O{sub 3} nanoparticles were prepared via a facile one-pot ball-milling route. {yields} Sb{sub 2}O{sub 3} based coatings have high solar reflectance properties. {yields} Sb{sub 2}O{sub 3} based coatings have excellent thermal insulation properties. {yields} Sb{sub 2}O{sub 3} based coatings may find applications in the energy saving of constructions. - Abstract: An efficient solar reflective thermal insulating coatings (SRCs) based on Y-stabilized Sb{sub 2}O{sub 3} nanoparticles has been prepared via a facile one-pot ball-milling route. Y-stabilized Sb{sub 2}O{sub 3} have smaller particle size (about 5 nm), disperse more evenly in coating films and exhibit higher solar reflectance compared with pure Sb{sub 2}O{sub 3}. Y-stabilized Sb{sub 2}O{sub 3} SRCs have the reflectance of more than 90% in the region 450-1600 nm and more than 80% in the region 1600-2200 nm and excellent thermal insulating properties. The observed solar reflectance properties of Y-stabilized Sb{sub 2}O{sub 3} SRCs were explained on the basis of the electronic structure of the material and physical parameters such as mean particle size (crystallite size) and refractive index. Due to its high solar reflectance and excellent thermal insulation properties, as-prepared Y-stabilized Sb{sub 2}O{sub 3} SRCs maybe a promising candidate for the energy saving applications in the constructions and industry furnishment.

  2. Characterization of γ- Al{sub 2}O{sub 3} nanopowders synthesized by Co-precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Jbara, Ahmed S., E-mail: ahmedsbhe@yahoo.com [Center for Sustainable Nanomaterials, Universiti Teknologi Malaysia, Skudai - 81310, Johor Bahru (Malaysia); Physics Department, Science College, Al-Muthanna University, Samawah - 66001 (Iraq); Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, Skudai - 81310, Johor Bahru (Malaysia); Othaman, Zulkafli [Center for Sustainable Nanomaterials, Universiti Teknologi Malaysia, Skudai - 81310, Johor Bahru (Malaysia); Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, Skudai - 81310, Johor Bahru (Malaysia); Ati, Ali A. [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, Skudai - 81310, Johor Bahru (Malaysia); Saeed, M.A., E-mail: moalsd@gmail.com [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, Skudai - 81310, Johor Bahru (Malaysia); Division of Science and Technology, University of Education, Township, Lahore - 54770 (Pakistan)

    2017-02-15

    Co-precipitation technique has been used to synthesize gamma-Al{sub 2}O{sub 3} (γ-Al{sub 2}O{sub 3}) nanopowders under annealing temperature effect. The crystalline phase and purity for the prepared powder were characterized by different spectroscopy techniques. XRD analysis confirms the gamma phase of alumina nanopowders with particle diameter ranging from 6 to 24 nm, which confirms the quantum dots formation, which is also supported by the BET measurement. The surface area of the prepared nanopowders is in the range of 109–367 m{sup 2}/g. Morphology analysis indicates that γ-Al{sub 2}O{sub 3} nanopowders are consisted of grains almost spherical in shape. Some agglomeration of nanoparticles occurs, which become more regular hexagonal shaped with the increasing annealing temperature. The small nanoparticles size and the high surface area from a simple procedure for preparing γ-Al{sub 2}O{sub 3} may make it more suitable for use as an adsorbent for malachite green. - Highlights: • Co-precipitation technique is used to synthesize gamma- Al{sub 2}O{sub 3} nanopowders. • Pure gamma- Al{sub 2}O{sub 3} phase was obtained having maximum nanoparticle size is 24 nm. • The quantum dots were formed inside powder. • High surface area of nanopowders at the low annealing temperature. • Increasing annealing temperature causes the hexagonal agglomeration shape.

  3. Sm{sub 2}O{sub 3} nanoparticles green synthesis via Callistemon viminalis' extract

    Energy Technology Data Exchange (ETDEWEB)

    Sone, B.T.; Manikandan, E.; Gurib-Fakim, A. [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), Materials Research Department, iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129, Western Cape Province (South Africa); Maaza, M., E-mail: Maaza@tlabs.ac.za [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), Materials Research Department, iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129, Western Cape Province (South Africa)

    2015-11-25

    In this contribution, it is demonstrated for the first time in the literature the possibility of synthesizing Sm{sub 2}O{sub 3} nano-scaled particles as small as 〈ϕ{sub particles}〉 ∼21.9 ± 5 nm using an entirely new green process. This latter is based on the usage of natural extract of the Callistemon viminalis as a strong chelating agent at room temperature. The selected area electron diffraction and the high resolution transmission electron microscopy confirmed the polycrystallinity of the Sm{sub 2}O{sub 3} nano-particles upon annealing at 500 °C. The complementary investigations by X-rays diffraction, infrared, Raman and X-rays photoelectron spectroscopy substantiated the single phase and the elemental purity of the Sm{sub 2}O{sub 3} nano-particles. - Highlights: • 1st time synthesis of a rare earth oxide Sm{sub 2}O{sub 3} nanoparticles by a green process via Callistemon viminalis flower extract. • Callistemon viminalis's natural extract was used as an effective chelating agent. • Pure Sm{sub 2}O{sub 3} nanoparticles were confirmed via HRTEM, XRD, ATR-FTIR, Raman, and XPS.

  4. Ostwald-ripening and particle size focussing of sub-10 nm NaYF4 upconversion nanocrystals

    Science.gov (United States)

    Rinkel, Thorben; Nordmann, Jörg; Raj, Athira Naduviledathu; Haase, Markus

    2014-11-01

    We have studied the growth behaviour of sub-10 nm NaYF4 upconversion nanocrystals of the hexagonal β-phase and the cubic α-phase. Ostwald-ripening of such particles in oleic acid/octadecene solvent results in broadening of the particle size distribution if the colloid contains particles of one crystal phase only. Narrow size distributions are formed only if β-phase particles grow in the presence of an excess of α-phase particles. Such binary mixtures of α-phase and β-phase particles form intrinsically when colloids of α-phase particles are heated for a sufficiently long time, because seeds of the β-phase nucleate in the solution after some time at high temperatures. Since the number of seeds determines the final size of the β-phase product, control of the nucleation is crucial for controlling the final particle size. We show that the number of β-phase seeds strongly depends on the composition of the α-phase known to form solid solutions Na1-xYF4-x in the range from x = 0 to x = 4/9. Sodium-deficient α-phase particles form a negligible number of β-phase seeds whereas α-phase particles with high sodium content yield a very large number of seeds. By taking advantage of this dependence and modifying the synthesis of the α-phase particles accordingly, small phase-pure β-NaYF4:Yb,Er particles with a size smaller than 6 nm can be prepared in oleic acid/octadecene just as well as much larger particles.We have studied the growth behaviour of sub-10 nm NaYF4 upconversion nanocrystals of the hexagonal β-phase and the cubic α-phase. Ostwald-ripening of such particles in oleic acid/octadecene solvent results in broadening of the particle size distribution if the colloid contains particles of one crystal phase only. Narrow size distributions are formed only if β-phase particles grow in the presence of an excess of α-phase particles. Such binary mixtures of α-phase and β-phase particles form intrinsically when colloids of α-phase particles are heated for a

  5. Pressure influenced combustion synthesis of {gamma}- and {alpha}-Al{sub 2}O{sub 3} nanocrystalline powders

    Energy Technology Data Exchange (ETDEWEB)

    Ozuna, O [Centro de Ciencias de la Materia Condensada, Universidad Nacional Autonoma de Mexico, Ensenada, BC, Mexico, CP 22800 (Mexico); Hirata, G A [Centro de Ciencias de la Materia Condensada, Universidad Nacional Autonoma de Mexico, Ensenada, BC, Mexico, CP 22800 (Mexico); McKittrick, J [Department of Mechanical Aerospace Engineering and Materials Science and Engineering Program, University of California at San Diego, La Jolla, CA 92093-0411 (United States)

    2004-04-21

    Aluminium oxide nanocrystals have been prepared via a straightforward reaction, initiated at low temperatures (<300 deg. C), between aluminium nitrate and hydrazine. The initial pressure parameter is found to be responsible for the variations of the particle size (ranging from nanocrystalline to sub-microcrystalline) and for the resulting crystalline phase ({gamma}- or {alpha}-Al{sub 2}O{sub 3}) of these powders. The fibre-like morphology obtained for the as-synthesized {gamma}-Al{sub 2}O{sub 3} permits the synthesis of nanocrystalline {alpha}-Al{sub 2}O{sub 3} ({approx} 55 nm) even after a high temperature treatment at 1200 deg. C. The findings suggest a promising approach for controlling the size and crystal phase of the particles.

  6. Magnetic properties and anisotropic magnetoresistance of antiperovskite nitride Mn{sub 3}GaN/Co{sub 3}FeN exchange-coupled bilayers

    Energy Technology Data Exchange (ETDEWEB)

    Sakakibara, H., E-mail: sakakibara.hideki@a.mbox.nagoya-u.ac.jp; Ando, H.; Kuroki, Y.; Kawai, S.; Ueda, K.; Asano, H. [Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

    2015-05-07

    Epitaxial bilayers of antiferromagnetic Mn{sub 3}GaN/ferromagnetic Co{sub 3}FeN with an antiperovskite structure were grown by reactive magnetron sputtering, and their structural, magnetic, and electrical properties were investigated. Exchange coupling with an exchange field H{sub ex} of 0.4 kOe at 4 K was observed for Mn{sub 3}GaN (20 nm)/Co{sub 3}FeN (5 nm) bilayers. Negative anisotropic magnetoresistance (AMR) effect in Co{sub 3}FeN was observed and utilized to detect magnetization reversal in exchange-coupled Mn{sub 3}GaN/Co{sub 3}FeN bilayers. The AMR results showed evidence for current-induced spin transfer torque in antiferromagnetic Mn{sub 3}GaN.

  7. Synthesis and characterization of BaTiO{sub 3} nanoparticles in oxygen atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes, S., E-mail: sfuentes@ucn.c [Departamento de Quimica y Farmacia, Facultad de Ciencias, Universidad Catolica del Norte, Casilla 1280, Antofagasta (Chile); Center for the Development of Nanoscience and Nanotechnology, CEDENNA, Santiago (Chile); Zarate, R.A.; Chavez, E. [Departamento de Fisica, Facultad de Ciencias, Universidad Catolica del Norte, Casilla 1280, Antofagasta (Chile); Munoz, P. [Departamento de Quimica, Facultad de Ciencias, Universidad Catolica del Norte, Casilla 1280, Antofagasta (Chile); Center for the Development of Nanoscience and Nanotechnology, CEDENNA, Santiago (Chile); Ayala, M. [Departamento de Quimica, Facultad de Ciencias, Universidad Catolica del Norte, Casilla 1280, Antofagasta (Chile); Espinoza-Gonzalez, R. [Departamento de Ciencia de los Materiales, Facultad de Ciencias Fisicas y Matematicas, Universidad de Chile, Av. Tupper 2069, Santiago (Chile); Leyton, P. [Laboratorio de Fotofisica y Espectroscopia Molecular, Instituto de Quimica, Pontificia Universidad Catolica de Valparaiso, Av. Brasil 2950, Valparaiso (Chile)

    2010-09-03

    A new synthesis route to obtain high-purity barium titanate, BaTiO{sub 3}, using the sol-gel-hydrothermal reaction of TiCl{sub 4} and a BaCl{sub 2} solution in an oxygen atmosphere has been developed. The synthesized BaTiO{sub 3} nanoparticles are nearly spherical. Their grain sizes are determined by the reaction temperature, reaching values as low as 50 nm when the particles are synthesized at 200 {sup o}C; interestingly even those particles with the smallest grain sizes displayed a ferroelectric behavior as characterized by a polarization hysteresis loop. The microstructure and composition of the as-synthesized samples were investigated by X-ray diffraction (XRD), high-resolution TEM (HRTEM), Raman spectroscopy, atomic force microscopy (AFM) and energy-dispersive X-ray spectroscopy (EDS).

  8. Mechanically activated synthesis of nanocrystalline ternary carbide Fe{sub 3}Mo{sub 3}C

    Energy Technology Data Exchange (ETDEWEB)

    Zakeri, M. [Materials Science Department, Islamic Azad University (Saveh branch), Saveh (Iran, Islamic Republic of)], E-mail: M_zakeri@iau-saveh.ac.ir; Rahimipour, M.R. [Ceramic Department, Materials and Energy Research Center, Tehran (Iran, Islamic Republic of); Khanmohammadian, A. [Materials Science Department, Islamic Azad University (Saveh branch), Saveh (Iran, Islamic Republic of)

    2008-09-25

    In this investigation, Fe{sub 3}Mo{sub 3}C ternary carbide was synthesized from the elemental powders of 3Mo/3Fe/C by mechanical milling and subsequent heat treatment. Structural and morphological evolutions of powders were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results showed that no phase transformation occurs during milling. A nanostructure Mo (Fe) solid solution obtained after 30 h of milling. With increasing milling time to 70 h no change takes place except grain size reduction to 9 nm and strain enhancement to 0.86%. Milled powders have spheroid shape and very narrow size distribution about 2 {mu}m at the end of milling. Fe{sub 3}Mo{sub 3}C was synthesized during annealing of 70 h milled sample at 700 deg. C. Undesired phases of MoOC and Fe{sub 2}C form at 1100 deg. C. No transformation takes place during annealing of 10 h milled sample at 700 deg. C. Mean grain size and strain get to 69 nm and 0.23% respectively with annealing of 70 h milled sample at 1100 deg. C.

  9. Synthesis and characterization of BiFeO{sub 3} for photocatalytic degradation of azo dye

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Manpreet, E-mail: manpreet.kaur@thapar.edu; Uniyal, Poonam, E-mail: uniyalpoonam@gmail.com [School of Physics and Materials Science, Thapar University, Patiala-147 004, Punjab (India)

    2015-08-28

    A novel approach is reported to synthesize single phase BiFeO{sub 3} via. sol-gel auto combustion method using glycine as fuel. Synthesized powder was subjected to annealing at different temperatures, i.e. 400 °C, 450 °C, 500 °C, 550 °C, and 600°C. Crystal structure of BiFeO{sub 3} samples examined by X-ray diffraction indicates that the samples were single-phased with different particle sizes, as particle sizes are temperature dependent and crystallized in rhombohedral structure. As the temperature was increased, the diffraction peak intensity of BiFeO3 in the XRD spectra gradually enhanced and the diffraction peaks became sharper. The optical properties of the resultant BiFeO{sub 3} were characterized using UV-Vis spectrophotometer over the range of 350-800 nm. UV-vis spectra of all the samples indicate that optical band gap lies in the visible region in the range of 2.2-2.07 eV at all temperatures. Moreover, photocatalytic properties of the BiFeO{sub 3} powders were investigated by the photodegradation of Reactive Black-5 (RB-5)

  10. Synthesis and study of bifunctional core–shell nanostructures based on ZnO@Gd{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Babayevska, Nataliya, E-mail: natbab@amu.edu.pl; Nowaczyk, Grzegorz; Jarek, Marcin; Załęski, Karol; Jurga, Stefan

    2016-07-05

    Bifunctional nanostructures based on ZnO nanoparticles (NPs) with controlled Gd{sub 2}O{sub 3} shell thicknesses were obtained by simple low-temperature methods (sol–gel technique and seed deposition method). The morphology, nanostructure, phase and chemical composition as well as luminescent and magnetic properties of the obtained core–shell nanostructures were investigated by transmission electron microscopy (HRTEM), energy dispersive x-ray spectroscopy (EDS), x-ray diffraction (XRD) techniques, optical spectroscopy, and SQUID magnetometer. As-obtained ZnO NPs are highly monodispersed and crystalline with mean particles size distribution of about 7 nm. Modification of the ZnO NPs surface by Gd{sub 2}O{sub 3} shell leads to an increase of the ZnO particles size up to 80–160 nm and the formation the Gd{sub 2}O{sub 3} shell with size of 2–4 nm. The dependence of the phase composition, luminescent and magnetic properties on Gd{sub 2}O{sub 3} content are also discussed. - Highlights: • The bifunctional ZnO@Gd{sub 2}O{sub 3} nanostructures were obtained by sol–gel technique. • ZnO@Gd{sub 2}O{sub 3} have intensive luminescence in the visible range under 325 nm excitation. • Gd{sup 3+} content allows to control paramagnetic properties of the ZnO@Gd{sub 2}O{sub 3}. • ZnO@Gd{sub 2}O{sub 3} nanostructures are potential objects for application in medicine.

  11. Heat dissipation and magnetic properties of surface-coated Fe{sub 3}O{sub 4} nanoparticles for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Tomitaka, Asahi; Ueda, Koji; Yamada, Tsutomu [Department of Electrical and Computer Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501 (Japan); Takemura, Yasushi, E-mail: takemura@ynu.ac.jp [Department of Electrical and Computer Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501 (Japan)

    2012-10-15

    In this study, the influence of surface coating on the magnetic and heat dissipation properties of Fe{sub 3}O{sub 4} nanoparticles was investigated. Fe{sub 3}O{sub 4} nanoparticles that ranged in size between (particle sizes of 20 and 30 nm) were coated with polyethylenimine (PEI), oleic acid, and Pluronic F-127. Surface coatings that were composed of thick layers of oleic acid and Pluronic F-127 reduced dipole interactions between the particles, and resulted in reduced coercivity and decreased Neel relaxation times. The ac magnetization measurements revealed that the heat dissipation of the PEI-coated Fe{sub 3}O{sub 4} nanoparticles was induced by hysteresis loss and Brownian relaxation loss and that of the oleic-acid-coated Fe{sub 3}O{sub 4} nanoparticles was mainly induced by hysteresis loss and Neel relaxation loss.

  12. Fabrication of Li{sub 2}O-B{sub 2}O{sub 3}-P{sub 2}O{sub 5} solid electrolyte by flame-assisted ultrasonic spray hydrolysis for thin film battery

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Ki-Hyun [Division of Material Science and Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); You, Hyun-Jin [Division of Material Science and Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Youn, Yong-Seb [Division of Material Science and Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Kim, Ji-Suk [Division of Material Science and Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Shin, Dong-Wook [Division of Material Science and Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of)]. E-mail: dwshin@hanyang.ac.kr

    2006-12-01

    Li{sub 2}O-B{sub 2}O{sub 3}-P{sub 2}O{sub 5} glass soot was fabricated from aqueous precursor solution of a CH{sub 3}CO{sub 2}Li.2H{sub 2}O and BCl{sub 3}, POCl{sub 3} by the flame-assisted ultrasonic spray hydrolysis. The aqueous precursor solution of the lithium acetates was first atomized with an ultrasonic vibrator (1.7 MHz). B{sub 2}O{sub 3} and P{sub 2}O{sub 5} were formed from BCl{sub 3} and POCl{sub 3} by oxy-hydrogen flame. Their properties were investigated by SEM, XRD, TGA-DSC and impedance analyzer. The formed particles in glass soot had spherical shape and the size of approximately 50-100 nm. XRD analysis revealed that the amorphous phase and crystalline phases were mixed in glass soot and the crystalline phases were B(OH){sub 3} and B{sub 2}O{sub 3}. The crystalline B(OH){sub 3} and B{sub 2}O{sub 3} found in glass soot completely disappeared by heat treatment. Conductivity was measured by complex impedance method using impedance analyzer and the conductivity was 10{sup -8} S/cm.

  13. Fe{sub 3}O{sub 4}/carbon nanocomposite: Investigation of capacitive & magnetic properties for supercapacitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Sinan, Neriman, E-mail: sinanneriman@gmail.com [Department of Advanced Technologies, Materials Science and Engineering Program, Bursa Technical University, Yildirim 16310, Bursa (Turkey); Unur, Ece, E-mail: eceunur@yahoo.com [Department of Energy Systems Engineering, Bursa Technical University, Yildirim 16310, Bursa (Turkey)

    2016-11-01

    Fe{sub 3}O{sub 4} nanoparticles with ∼10 nm diameters were synthesized by an extremely low-cost, scalable and relatively biocompatible chemical co-precipitation method. Magnetic measurements revealed that Fe{sub 3}O{sub 4} nanoparticles have bifunctional superparamagnetic and ferromagnetic character with saturation magnetization (M{sub s}) values of 64 and 71 emu g{sup −1} at 298 K and 10 K, respectively. Pseudocapacitive Fe{sub 3}O{sub 4} nanoparticles were then integrated into hazelnut shells - an abundant agricultural biomass - by an energy efficient hydrothermal carbonization method. Presence of magnesium oxide (MgO) ceramic template or its precursor in the hydrothermal reactor allowed simultaneous introduction of pores into the composite structure. Hierarchically micro-mesoporous Fe{sub 3}O{sub 4}/C nanocomposite possesses a high specific surface area of 344 m{sup 2} g{sup −1}. Electrochemical properties of Fe{sub 3}O{sub 4}/C nanocomposite were investigated by cyclic voltammetry and galvanostatic charge-discharge measurements in a conventional three-electrode cell. The Fe{sub 3}O{sub 4}/C nanocomposite is able to operate in a large negative potential window in 1 M Na{sub 2}SO{sub 4} aqueous electrolyte (−1.2–0 V vs. Ag/AgCl). Synergistic effect of the Fe{sub 3}O{sub 4} and carbon leads to enhanced specific capacitance, rate capability and cyclability making Fe{sub 3}O{sub 4}/C nanocomposite a very promising negative electrode material for asymmetric supercapacitors. - Highlights: • Fe{sub 3}O{sub 4} (magnetite) particles with ∼10 nm dia. were prepared by a facile chemical co-precipitation. • Fe{sub 3}O{sub 4} nanospheres are superparamagnetic at 298K with high saturation magnetization of 64 emu g{sup −1}. • Porous Fe{sub 3}O{sub 4}/C nanocomposite was also prepared by a green HTC method combined with MgO templating. • Electrochemical properties of Fe{sub 3}O{sub 4}/C were studied in 1 M Na{sub 2}SO{sub 4} (between −1.2 and 0 V vs. Ag

  14. A simple large-scale synthesis of mesoporous In{sub 2}O{sub 3} for gas sensing applications

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Su; Song, Peng, E-mail: mse_songp@ujn.edu.cn; Yan, Huihui; Yang, Zhongxi; Wang, Qi, E-mail: mse_wangq@ujn.edu.cn

    2016-08-15

    Graphical abstract: Large-scale mesoporous In{sub 2}O{sub 3} nanostructures for gas-sensing applications were successfully fabricated via a facile Lewis acid catalytic the furfural alcohol resin template route. - Highlights: • Mesoporous In{sub 2}O{sub 3} nanostructures with high-yield have been successfully fabricated via a facile strategy. • The microstructure and formation mechanism of mesoporous In{sub 2}O{sub 3} nanostructures were discussed based on the experimental results. • The as-prepared In{sub 2}O{sub 3} samples exhibited high response, short response-recovery times and good selectivity to ethanol gas. - Abstract: In this paper, large-scale mesoporous In{sub 2}O{sub 3} nanostructures were synthesized by a facile Lewis acid catalytic the furfural alcohol resin (FAR) template route for the high-yield. Their morphology and structure were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential thermal and thermogravimetry analysis (DSC-TG) and the Brunauer-Emmett-Teller (BET) approach. The as-obtained mesoporous In{sub 2}O{sub 3} nanostructures possess excellent mesoporous and network structure, which increases the contact area with the gases, it is conducive for adsorption-desorption of gas on the surface of In{sub 2}O{sub 3}. The In{sub 2}O{sub 3} particles and pores were both about 15 nm and very uniform. In gas-sensing measurements with target gases, the gas sensor based on mesoporous In{sub 2}O{sub 3} nanostructures showed a good response, short response-recovery time, good selectivity and stability to ethanol. These properties are due to the large specific surface area of mesoporous structure. This synthetic method could use as a new design concept for functional mesoporous nanomaterials and for mass production.

  15. Lyothermal synthesis of nanocrystalline BaTiO{sub 3} and TiO{sub 2} powders

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, A.; Berger, A.; Sporn, D. [Fraunhofer-Institut fuer Silicatforschung, Wuerzburg (Germany); Bertagnolli, H. [Universitaet Stuttgart (Germany)

    1995-09-01

    The synthesis of BaTiO{sub 3} and powders has been investigated at a temperature of 175{degrees}C and pressures between 0.1 MPa and MPa, starting from TiO{sub 2}{center_dot}xH{sub 2}O and Ba(OH){sub 2}{center_dot}8H{sub 2}O in the solvents of pure water, 1,5-pentanediol and in different mixtures of both. The influence of feedstock concentration and the reaction time on particle growth and habit formation was studied by TEM and XRD. When starting with a higher feedstock concentration at short reaction times (2h), then the BaTiO{sub 3} particle size and habit changed from single crystal dendrites (up to 700 nm in size) to small individual particles (100 nm) with uniform crystallite shapes. An increasing proportion of aggregated particles is observed at extended reaction times at any feedstock concentration investigated The influence of solvent on particle growth was investigated by the use of different 1,5-pentanediol to water mixtures (lyothermal synthesis). By increasing the 1,5-pentanediol to water ratio the primary particle size of BaTiO{sub 3} was reduced from about 700 nm to 15 nm. The reduction of the particle size is probably due to the higher viscosity of 1,5-pentanediol compared to water, and the decrease of diffusivity and concentration of Ba{sup 2+}-ions involved. Hence, the particle size can be controlled by the choice of the solvent mixture.

  16. Synthesis of g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} heterojunction with enhanced photocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    He, Peizhi; Song, Limin [College of Environment and Chemical Engineering and State Key Laboratory of Hollow-Fiber Membrane Materials and Membrane Processes, Tianjin Polytechnic University, Tianjin 300387 (China); Zhang, Shujuan, E-mail: songlmnk@sohu.com [College of Science, Tianjin University of Science and Technology (co-first institution), Tianjin 300457 (China); Wu, Xiaoqing [Institute of Composite Materials and Ministry of Education Key Laboratory of Advanced Textile Composite Materials, Tianjin Polytechnic University, Tianjin 300387 (China); Wei, Qingwu [College of Environment and Chemical Engineering and State Key Laboratory of Hollow-Fiber Membrane Materials and Membrane Processes, Tianjin Polytechnic University, Tianjin 300387 (China)

    2014-03-01

    Graphical abstract: g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} heterojunction photocatalyst with visible-light response was prepared by a facile coprecipitation method. The results show that g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} possesses a much higher activity for the decomposition of RhB than that of the pure Ag{sub 3}PO{sub 4} particles. The most mechanism is that g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} heterojunction photocatalyst can efficiently separate the photogenerated electron–hole pairs, enhancing the photocatalytic activity of g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} composites. - Highlights: • g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} heterojunction showed much higher activity than that of Ag{sub 3}PO{sub 4}. • The high activity could be attributed to g-C{sub 3}N{sub 4} for modifying Ag{sub 3}PO{sub 4}. • More ·OH radicals may be significant reason to improve Ag{sub 3}PO{sub 4} activity. - Abstract: g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} heterojunction photocatalyst with visible-light response was prepared by a facile coprecipitation method. The photocatalysts were characterized by X-ray powder diffraction, transmission electron microscopy, UV–vis absorption spectroscopy and Fourier transform infrared spectroscopy. The photocatalytic activities of the obtained samples were tested by using Rhodamine B (RhB) as the degradation target under visible light irradiation. g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} decomposed RhB more effectively than the pure Ag{sub 3}PO{sub 4} particles did, and 2 wt.% g-C{sub 3}N{sub 4} had the highest activity. Furthermore, 2 wt.% g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} degraded high-concentration RhB more potently than unmodified Ag{sub 3}PO{sub 4} did, probably because g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} heterojunction photocatalyst enhanced the photocatalytic activity by efficiently separating the photogenerated electron–hole pairs.

  17. Effect of sintering temperature on the optical properties of BiFeO{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Jalandhara, Devender, E-mail: devj713@gmail.com; Singh, Gurdhir; Yadav, Kamlesh, E-mail: kamlesh.yadav001@gmail.com [Centre for Physical Sciences, Central University of Punjab, Bathinda-151001 (India)

    2016-05-06

    BiFeO{sub 3} is a multiferroic material which exhibits excellent optical properties. BiFeO{sub 3} nanoparticles are synthesized by using sol-gel method. The prepared samples are sintered at 500°C, 600°C, 700°C, 800°C and 850°C. In this paper, the effect of sintering temperature on the optical properties in BiFeO{sub 3} nanoparticles is studied. Field emission electron microscopy (FESEM) images show that particles are nearly spherical in shape. It is found that the particles size increases from 37 nm to 51 nm with increasing the sintering temperature. FESEM images also reveal a homogenous size distribution of nanoparticles. All the functional groups are indexed in the Fourier transform infrared spectroscopy (FTIR) spectra. It is found that Fe-O stretching peaks are appeared in the wave number range 447 and 507 cm{sup −1}. The value of energy band gap are found 2.14, 2.26, 2.30, 2.36, and 2.54 eV for the samples sintered at 500°C, 600°C, 700°C, 800°C and 850°C respectively. Thus, the increase in band gap with increasing temperature has been observed. The present samples can be used as photo-catalyst, in non-volatile memories and to make spintronics devices.

  18. Effect of microstrain on the magnetic properties of BiFeO{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Mocherla, Pavana S. V.; Sudakar, C., E-mail: csudakar@iitm.ac.in [Multifunctional Materials Laboratory, Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India); Karthik, C.; Ubic, R. [Department of Materials Science and Engineering, Boise State University, 1910 University Drive, Boise, Idaho 83725 (United States); Ramachandra Rao, M. S. [Department of Physics and Nano Functional Materials Technology Centre, Indian Institute of Technology Madras, Chennai 600036 (India)

    2014-09-29

    We report on size induced microstrain-dependent magnetic properties of BiFeO{sub 3} nanoparticles. The microstrain is found to be high (ε > 0.3%) for smaller crystallite sizes (d < 30 nm), and shows a sharp decrease as the particle size increases. The presence of pseudo-cubic symmetry is evidenced for these nanoparticles. Raman spectral studies suggest straightening of the Fe-O-Fe bond angle accompanied by a decrease in FeO{sub 6} octahedral rotation for d < 65 nm. The magnetization shows a dip around 30 nm, half the size of spin cycloid length for BiFeO{sub 3}, due to a decrease in rhombohedral distortion with crystallite size. We also observe a similar trend in the T{sub N} with respect to size indicating that the microstrain plays a significant role in controlling the magnetic property of BiFeO{sub 3}.

  19. A reduced graphene oxide/Co<sub>3O4 composite for supercapacitor electrode

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, Chengcheng; Li, Ming; Zhi, Mingjia; Manivannan, Ayyakkannu; Wu, Nianqiang

    2013-03-01

    20 nm sized Co<sub>3O4 nanoparticles are in-situ grown on the chemically reduced graphene oxide (rGO) sheets to form a rGO-Co<sub>3O4 composite during hydrothermal processing. The rGO-Co<sub>3O4 composite is employed as the pseudocapacitor electrode in the 2 M KOH aqueous electrolyte solution. The rGOCo<sub>3O4 composite electrode exhibits a specific capacitance of 472 F/g at a scan rate of 2 mV/s in a two-electrode cell. 82.6% of capacitance is retained when the scan rate increases to 100 mV/s. The rGOCo<sub>3O4 composite electrode shows high rate capability and excellent long-term stability. It also exhibits high energy density at relatively high power density. The energy density reaches 39.0 Wh/kg at a power density of 8.3 kW/kg. The super performance of the composite electrode is attributed to the synergistic effects of small size and good redox activity of the Co<sub>3O4 particles combined with high electronic conductivity of the rGO sheets.

  20. Synthesis and characterization particles of Ba{sub 0,50}Sr{sub 0,50}Co{sub 0,80}Fe{sub 0,20}O{sub 3} obtained by the citrate-EDTA technique; Sintese e caracterizacao de particulados de Ba{sub 0,50}Sr{sub 0,50}Co{sub 0,80}Fe{sub 0,20}O{sub 3} obtidos pela tecnica dos citratos-EDTA

    Energy Technology Data Exchange (ETDEWEB)

    Bonturim, E.; Vargas, R.A.; Andreoli, M.; Seo, E.S.M., E-mail: ebonturim@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (CCTM/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencia e Tecnologia de Materiais

    2010-07-01

    The Ba{sub (1-x)}Sr{sub (x)}Co{sub (1-y)}Fe{sub (y)}O{sub (3)} (BSCF) has been studied as a cathode material for Intermediate Temperature Solid Oxide Fuel Cell, due to its better ion and electron conduction. This work aims to study the synthesis of the compound obtained from the citrate-EDTA technique. Thermogravimetric analysis indicated the formation of the compound above 800 deg C. The materials calcined at temperatures of 700, 800 and 900 deg C for 5 h showed cubic pseudo-perovskite structure, according to the literature. By analysis of X-ray fluorescence were obtained powders with nominal chemical composition in the temperature range studied. The micrographs obtained by SEM and particle size distribution analysis showed the formation of particle with diameters below 1 micron. (author)

  1. Preparation of novel Sb{sub 2}O{sub 3}/WO{sub 3} photocatalysts and their activities under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    He, Guo-Hua; Liang, Can-Jian; Ou, Yu-Da; Liu, Dan-Ni; Fang, Yue-Ping [Institute of Biomaterial, College of Science, South China Agricultural University, Guangzhou 510642 (China); Xu, Yue-Hua, E-mail: xuyuehua@scau.edu.cn [Institute of Biomaterial, College of Science, South China Agricultural University, Guangzhou 510642 (China)

    2013-06-01

    Highlights: ► Visible-light-driven Sb{sub 2}O{sub 3}/WO{sub 3} photocatalysts were synthesized. ► Results showed that RhB can be decomposed using a 4 W LED lamp as visible light. ► The coupling of Sb{sub 2}O{sub 3} and WO{sub 3} enhanced the photocatalytic activity of WO{sub 3}. - Abstract: Novel visible-light-driven Sb{sub 2}O{sub 3}/WO{sub 3} photocatalysts were prepared by a hydrothermal synthesis followed by heat treatment, and characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), BET surface area, Fourier transform infrared spectroscopy (FT-IR) and photoluminescence spectra (PL). The photocatalytic activities of Sb{sub 2}O{sub 3}/WO{sub 3} photocatalysts were evaluated by the rhodamine B degradation using a LED lamp as visible light irradiation. Compared with pure WO{sub 3} and Sb{sub 2}O{sub 3}, the significantly enhanced photocatalytic activities of the Sb{sub 2}O{sub 3}/WO{sub 3} composite particles are attributed to the decrease of the recombination rate of photoinduced electron–hole pairs due to the coupling of Sb{sub 2}O{sub 3} and WO{sub 3} within the composite nanoparticles. Studies of Sb{sub 2}O{sub 3}/WO{sub 3} composites indicate that one approach to design composite materials with enhanced photocatalytic performance is through coupling Sb{sub 2}O{sub 3} with WO{sub 3}, which the lowest energy states for electrons and holes are in different semiconductors.

  2. A novel blue-greenish emitting phosphor Ba{sub 3}LaK(PO{sub 4}){sub 3}F:Tb{sup 3+} with high thermal stability

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Chao; Huang, Hongwei, E-mail: hhw@cugb.edu.cn; Hu, Yingmo, E-mail: huyingmo@cugb.edu.cn; Miao, Shihai; Zhou, Jun

    2016-04-15

    Highlights: • The Ba{sub 3}LaK(PO{sub 4}){sub 3}F:Tb{sup 3+} phosphors exhibit a broad excitation band. • The Ba{sub 3}LaK(PO{sub 4}){sub 3}F:Tb{sup 3+} emission color adjust from blue to green. • The Ba{sub 3}LaK(PO{sub 4}){sub 3}F:Tb{sup 3+} show superior thermal stability. - Abstract: Ba{sub 3}La{sub 1−m}K(PO{sub 4}){sub 3}F:mTb{sup 3+}(m = 0.01–0.50) phosphors have been prepared by a traditional high temperature solid-state reaction. XRD analysis verified the apatite-type phase structure of the as-prepared samples, and the morphology has been checked by the Scanning electron microscope (SEM). The emission spectrum of Ba{sub 3}LaK(PO{sub 4}){sub 3}F:Tb{sup 3+} phosphor consists of two regions, blue emission band from 380 to 470 nm and green emission band from 470 to 650 nm. With increasing Tb{sup 3+} ions doped concentration (m), the color hue of Ba{sub 3}La{sub 1−m}K(PO{sub 4}){sub 3}F:mTb{sup 3+}adjusts from blue to green. On the basis of concentration quenching method, the critical distance between Tb{sup 3+} ions is calculated to be 7.98 Å, suggesting that multipolar interaction predominate in quenching process. In addition, the temperature-dependence PL spectra of Ba{sub 3}LaK(PO{sub 4}){sub 3}F:0.01Tb{sup 3+} and Ba{sub 3}LaK(PO{sub 4}){sub 3}F:0.40Tb{sup 3+} phosphor are given,which exhibit superior thermal stability.

  3. Structural characterization and ytterbium spectroscopy in Sc{sub 2}O{sub 3} nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Galceran, M. [Fisica i Cristal.lografia de Materials i Nanomaterials (FiCMA-FiCNA), Universitat Rovira i Virgili (URV), Campus Sescelades, c/ Marcel. li Domingo, s/n, E-43007 Tarragona (Spain); Pujol, M.C., E-mail: mariacinta.pujol@urv.ca [Fisica i Cristal.lografia de Materials i Nanomaterials (FiCMA-FiCNA), Universitat Rovira i Virgili (URV), Campus Sescelades, c/ Marcel. li Domingo, s/n, E-43007 Tarragona (Spain); Carvajal, J.J.; Mateos, X. [Fisica i Cristal.lografia de Materials i Nanomaterials (FiCMA-FiCNA), Universitat Rovira i Virgili (URV), Campus Sescelades, c/ Marcel. li Domingo, s/n, E-43007 Tarragona (Spain); Zaldo, C. [Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Cientificas (CSIC), c/ Sor Juana Ines de la Cruz 3, E-28049 Madrid (Spain); Aguilo, M.; Diaz, F. [Fisica i Cristal.lografia de Materials i Nanomaterials (FiCMA-FiCNA), Universitat Rovira i Virgili (URV), Campus Sescelades, c/ Marcel. li Domingo, s/n, E-43007 Tarragona (Spain)

    2010-08-15

    Ytterbium-doped scandium oxide nanocrystals measuring less than 25 nm with compositions of Sc{sub 2-x}Yb{sub x}O{sub 3} (x=0.001-1) were prepared using the modified Pechini method. The Yb:Sc{sub 2}O{sub 3} nanocrystals were obtained by calcination at low temperature such as 1073 K for 2 h. X-ray powder diffraction (XRD) and transmission electronic microscopy (TEM) were used to perform the structural characterization of nanocrystals; these studies indicated that the nanocrystals have high crystalline quality with cubic structure and Ia3-bar space group. The morphology and particle size were studied using electron microscopy. A detailed study of the effect of the nanodimension and the ytterbium concentration on the spectroscopic characteristics of Yb{sup 3+} as an active ion was carried out in terms of optical absorption, optical emission and fluorescence decay time at room and low temperature.

  4. Mechanical alloying of Ni{sub 3}Fe in the presence of Ni{sub 3}Fe nanocrystalline germs

    Energy Technology Data Exchange (ETDEWEB)

    Sparchez, Z. [Materials Sciences and Technology Department, Technical University of Cluj-Napoca, 103-105 Muncii Avenue, 400641 Cluj-Napoca (Romania); Chicinas, I. [Materials Sciences and Technology Department, Technical University of Cluj-Napoca, 103-105 Muncii Avenue, 400641 Cluj-Napoca (Romania) and Laboratoire de Cristallographie, CNRS, associe a l' Universite J. Fourier, BP 166, F-38042 Grenoble Cedex 9 (France)]. E-mail: Ionel.Chicinas@stm.utcluj.ro; Isnard, O. [Laboratoire de Cristallographie, CNRS, associe a l' Universite J. Fourier, BP 166, F-38042 Grenoble Cedex 9 (France); Pop, V. [Faculty of Physics, Babes-Bolyai University, 400084 Cluj-Napoca (Romania); Popa, F. [Materials Sciences and Technology Department, Technical University of Cluj-Napoca, 103-105 Muncii Avenue, 400641 Cluj-Napoca (Romania); Laboratoire de Cristallographie, CNRS, associe a l' Universite J. Fourier, BP 166, F-38042 Grenoble Cedex 9 (France)

    2007-05-31

    The influence of nanocrystalline germs on the production of the Ni{sub 3}Fe intermetallic compound by mechanical alloying is reported. These germs consist in Ni{sub 3}Fe nanocrystalline particles previously obtained by mechanical alloying which have been added to the Ni-Fe mixture: 0.8(3Ni + Fe) + 0.2Ni{sub 3}Fe = Ni{sub 3}Fe. The powder mixture was milled in a planetary mill in argon atmosphere. Several milling times have been used ranging from 2 to 8 h. A Ni-Fe mixture at nominal composition of Ni{sub 3}Fe compound was milled in the same conditions, as blind samples. A heat treatment at 350 {sup o}C for 0.5, 1, 2 and 4 h has been performed in order to remove the internal stresses induced by milling and to improve the solid-state reaction. The formation of the Ni{sub 3}Fe phase was checked by X-ray diffraction and magnetic measurements. The germs inoculation improves the synthesis of the Ni{sub 3}Fe phase by combined mechanical alloying and annealing technique. This influence is more effective for short milling times (typically lower than 4 h). For samples milled more than 4 h the influence of the germs inoculation is more reduced, due to the Ni{sub 3}Fe germs self-formation by milling.

  5. Microstructural features of the La{sub 1−x}Ca{sub x}FeO{sub 3−δ} solid solutions prepared via Pechini route

    Energy Technology Data Exchange (ETDEWEB)

    Gerasimov, E.Yu., E-mail: gerasimov@catalysis.ru [Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Pr. Acad. Lavrentieva 5, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090 (Russian Federation); Isupova, L.A. [Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Pr. Acad. Lavrentieva 5, Novosibirsk 630090 (Russian Federation); Tsybulya, S.V. [Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Pr. Acad. Lavrentieva 5, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090 (Russian Federation)

    2015-10-15

    Highlights: • La{sub 1−x}Ca{sub x}FeO {sub (3−δ)} (0 ≤ x ≤ 0.7) perovskite were prepared by Pechini method. • Planar defects in direction (1 0 1) were observed in the perovskite surface. • α-Fe{sub 2}O{sub 3} particles (1–10 nm) on the surface of perovskite were revealed. • Amount of α-Fe{sub 2}O{sub 3} particles on the perovskite surface grew with rising x values. - Abstract: Solid solutions with La{sub 1−x}Ca{sub x}FeO{sub 3−δ} (0 ≤ x ≤ 0.7) perovskite-like structure prepared via Pechini route have been investigated by using high resolution transmission electron microscopy and X-ray diffraction. Extended planar defects lying in (1 0 1) crystallographic planes and α-Fe{sub 2}O{sub 3} nanoparticles on the surface of perovskite microcrystals are characteristic of the samples under investigation. It was found that testing of the samples in catalytic deep CH{sub 4} oxidation process results in partial destruction of solid solutions with formation of planar defects in the bulk and α-Fe{sub 2}O{sub 3} particles on the surface.

  6. Optical and structural study of In{sub 2}S{sub 3} thin films growth by co-evaporation and chemical bath deposition (CBD) on Cu{sub 3}BiS{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Mesa, F., E-mail: fgmesar@unal.edu.co [Unidad de Estudios Universitarios, Colegio Mayor de Nuestra Señora del Rosario, Cra. 24 N° 63C-69, Bogotá (Colombia); Chamorro, W. [Université de Lorraine, Institut Jean Lamour, Nancy (France); Hurtado, M. [Departamento de Quimica, Universidad Nacional de Colombia, Cra. 30 N° 45-03, Bogotá (Colombia); Departamento de Física, Universidad de los Andes, Calle 21 No. 1-20, Bogotá (Colombia)

    2015-09-30

    Highlights: • In{sub 2}S{sub 3} thin films usually grow like an ultrathin. • Samples grown by CBD have a higher degree of coverage of the substrate unlike co-evaporation method. • Solar cells of Al/TCO/In{sub 2}S{sub 3}/Cu{sub 3}BiS{sub 3}/Mo structure. • In{sub 2}S{sub 3} thin films were deposited on Cu{sub 3}BiS{sub 3} (CBS), with of In{sub 2}S{sub 3} β-phase with tetragonal structure. - Abstract: We present the growth of In{sub 2}S{sub 3} onto Cu{sub 3}BiS{sub 3} layers and soda-lime glass (SLG) substrates by using chemical bath deposition (CBD) and physical co-evaporation. The results reveal that the microstructure and the optical properties of the In{sub 2}S{sub 3} films are highly dependent on the growth method. X-ray diffractrograms show that In{sub 2}S{sub 3} films have a higher crystallinity when growing by co-evaporation than by CBD. In{sub 2}S{sub 3} thin films grown by CBD with a thickness below 170 nm have an amorphous structure however when increasing the thickness the films exhibit two diffraction peaks associated to the (1 0 3) and (1 0 7) planes of the β-In{sub 2}S{sub 3} tetragonal structure. It was also found that the In{sub 2}S{sub 3} films present an energy bandgap (E{sub g}) of about 2.75 eV, regardless of the thickness of the samples.

  7. The anomalous behaviour of Ag-Al sub 2 O sub 3 Cermet electroformed devices

    CERN Document Server

    Khan, M S R

    2003-01-01

    Cermet coating consisting of silver particles in an aluminium oxide matrix were prepared on glass substrates by vacuum deposition. Variation of the circulating current with potential difference was obtained in evaporated Al/Ag-Al sub 2 O sub 3 /Cu sandwich structures, 100 to 200 nm thick containing 10 wt % Ag. It was observed that the investigated sandwich structures exhibit anomalous behaviour such as electroforming with Voltage-Controlled-Negative Resistance (VCNR) in vacuo of approx 4 x 10 sup - sup 6 torr. The formed characteristics were explained on the basis of filamentary model.

  8. On the High Sensitivity of the Electronic States of 1 nm Gold Particles to Pretreatments and Modifiers

    Directory of Open Access Journals (Sweden)

    Oxana Martynyuk

    2016-03-01

    Full Text Available In this paper, the effect of modifiers and pretreatments on the electronic states of 1 nm gold nanoparticles (AuNPs supported on silica was systematically studied. AuNPs deposited on silica (particle size of 2–4 nm modified with Ce, La and Fe oxides, were studied by FTIR of adsorbed CO after different redox treatments at 100, 300 and 500 °C. This study was conducted at room temperature to allow detecting the electronic states of gold, which is more likely involved in CO oxidation at the same temperature. AuNP size distribution was measured by HRTEM. It is shown that the electronic state of gold species (Aunδ−, Au0, Aunδ+, Au+ in 1 nm AuNPs is sensitive to the modifier as well as to the temperatures of redox pretreatments. Supports modified with the same additives but containing larger AuNPs (~3, 4, 5, and 7 nm were also studied. They showed that Au0 remains stable irrespective of additives and redox pretreatments, indicating no significant effect of such treatments on the electronic properties of larger AuNPs. Samples with a predominant AuNP size of 2 nm are an intermediate case between these two groups of materials.

  9. Electrochromic device based on electrospun WO{sub 3} nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Dulgerbaki, Cigdem; Maslakci, Neslihan Nohut; Komur, Ali Ihsan; Oksuz, Aysegul Uygun, E-mail: ayseguluygun@sdu.edu.tr

    2015-12-15

    Highlights: • WO{sub 3} electrochromic nanofibers were prepared by electrospinning technique. • WO{sub 3} nanofibers switched reversibly from transparent to blue color. • Electrochromic device was assembled using ionic liquid based gel electrolyte. • Significant optical modulation and excellent cycling stability were achieved for ECD. - Abstract: The tungsten oxide (WO{sub 3}) nanofibers were grown directly onto an ITO-coated glass via an electrospinning method for electrochromic applications. The electrochromic properties of WO{sub 3} nanofibers were investigated in the presence of different electrolytes including a series of ionic liquids and classic LiClO{sub 4}-PC system. A significant optical modulation of 20.82% at 760 nm, reversible coloration with efficiency of 64.58 cm{sup 2}/C and excellent cycling stability were achieved for the nanofiber electrochromic device (ECD) with ionic liquid based gel electrolyte.

  10. Bacteria-assisted preparation of nano α-Fe{sub 2}O{sub 3} red pigment powders from waste ferrous sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiang; Wang, Chuankai; Zeng, Yu; Li, Panyu; Xie, Tonghui; Zhang, Yongkui, E-mail: zhangyongkui@scu.edu.cn

    2016-11-05

    Highlights: • A route to prepare nano α-Fe{sub 2}O{sub 3} red pigment from waste ferrous sulfate is proposed. • Acidithiobacillus ferrooxidans is introduced for accelerating iron oxidation. • The particle size of synthetic α-Fe{sub 2}O{sub 3} is ranged from 22 nm to 86 nm. • The prepared nano α-Fe{sub 2}O{sub 3} red pigment fulfills ISO 1248-2006. - Abstract: Massive ferrous sulfate with excess sulfuric acid is produced in titanium dioxide industry each year, ending up stockpiled or in landfills as solid waste, which is hazardous to environment and in urgent demand to be recycled. In this study, waste ferrous sulfate was used as a second raw material to synthesize nano α-Fe{sub 2}O{sub 3} red pigment powders with a bacteria-assisted oxidation process by Acidithiobacillus ferrooxidans. The synthesis route, mainly consisting of bio-oxidation, precipitation and calcination, was investigated by means of titration, thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray fluorescence (XRF) to obtain optimum conditions. Under the optimum conditions, nano α-Fe{sub 2}O{sub 3} red pigment powders contained 98.24 wt.% of Fe{sub 2}O{sub 3} were successfully prepared, with a morphology of spheroidal and particle size ranged from 22 nm to 86 nm and averaged at 45 nm. Moreover, the resulting product fulfilled ISO 1248-2006, the standards of iron oxide pigments.

  11. Synthesis and magnetic characterization of LaMnO{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, E.; Sagredo, V. [Universidad de Los Andes, Facultad de Ciencias, Laboratorio de Magnetismo, 5101 Merida (Venezuela, Bolivarian Republic of); Delgado, G. E. [Universidad de Los Andes, Facultad de Ciencias, Laboratorio de Cristalografia, 5101 Merida (Venezuela, Bolivarian Republic of)

    2015-07-01

    LaMnO{sub 3} nanoparticles system were prepared by the sol-gel auto-combustion method, in order to analyze the structure and magnetic behavior presented by the compound prepared following a new alternative route of synthesis. Structural characterization, morphology and crystallite size was performed by X-ray diffraction (XRD), infrared spectroscopy (IR) and electron microscopy. The XRD study together with a Rietveld analysis showed that the LaMnO{sub 3} compound crystallized in a perovskite hexagonal structure. The IR spectra showed that the compound has tensile energy bands in the Mn-O-Mn bonds related with the octahedron MnO{sub 6}; which are attributed to a characteristic vibration of the ABO{sub 3} perovskite. An estimated size and morphological analysis was carried out by applying the Scherrer formula and using transmission electron microscopy, revealing non-spherical shape and particle sizes between 13 nm and 18 nm. The magnetic measurements M(T) were performed by using zero field-cooled and field-cooled protocols which revealed a positive Weiss temperature indicating the presence of ferromagnetic interactions with a Curie temperature, T{sub C} = 150 K. (Author)

  12. Picosecond ultrafast pulsed laser deposition of SrTiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Pervolaraki, M., E-mail: pervolaraki@ucy.ac.cy [Department of Mechanical and Manufacturing Engineering and Nanotechnology Research Center, University of Cyprus, 75 Kallipoleos Avenue, P.O. Box 20537, 1678 Nicosia (Cyprus); Mihailescu, C.N. [Department of Mechanical and Manufacturing Engineering and Nanotechnology Research Center, University of Cyprus, 75 Kallipoleos Avenue, P.O. Box 20537, 1678 Nicosia (Cyprus); National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor Street, P.O. Box MG-36, 077125 Magurele (Romania); Luculescu, C.R. [National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor Street, P.O. Box MG-36, 077125 Magurele (Romania); Ionescu, P.; Dracea, M.D.; Pantelica, D. [Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH), 30 Reactorului Street, P.O. Box MG-6, RO-077125 Magurele (Romania); Giapintzakis, J., E-mail: giapintz@ucy.ac.cy [Department of Mechanical and Manufacturing Engineering and Nanotechnology Research Center, University of Cyprus, 75 Kallipoleos Avenue, P.O. Box 20537, 1678 Nicosia (Cyprus)

    2015-05-01

    Highlights: • Growth of SrTiO{sub 3} films by UFPLD using 10 ps pulses at 1064 nm. • Crystalline nearly stoichiometric films were deposited at 0.2 MHz. • A repetition rate threshold concerning crystallinity, stoichiometry and particle size was identified. - Abstract: SrTiO{sub 3} particle-composed films were grown on Si substrates via picosecond ultrafast pulsed laser deposition. We have investigated the effect of laser pulse repetition rate (0.2–8.2 MHz) and fluence (0.079–1.57 J cm{sup −2}) on the morphology, crystallinity and stoichiometry of the films. X-ray diffraction, energy dispersive X-ray spectroscopy and Rutherford backscattering spectroscopy measurements demonstrated that the as-grown films were nearly stoichiometric and composed of large particles when a pulse repetition rate of 0.2 MHz was employed. However, at the higher repetition rate of 8.2 MHz the particle size decreased and the stoichiometry was altered. Finally, we attribute the formation of micron-size particle-composed films to the slow translation speed in relation to the high pulse repetition rates (kHz–MHz regime)

  13. Synthesis and characterization of nanostructured CaZrO{sub 3} and BaZrO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Ibiapino, Amanda Laura; Figueiredo, Laysa Pires de [Departamento de Quimica, Instituto de Ciencias Exatas e da Terra, Universidade Federal do Mato Grosso, MT (Brazil); Lascalea, Gustavo E. [LISAMEN/CONICET, Ciudad de Mendoza (Argentina); Prado, Rogerio Junqueira, E-mail: rjprado@ufmt.br [Instituto de Fisica, Universidade Federal do Mato Grosso, Cuiaba - MT (Brazil)

    2013-09-01

    In this work, nanostructured samples of barium zirconate (BaZrO{sub 3}) and calcium zirconate (CaZrO{sub 3}) were synthesized by the gel-combustion method, using glycine as fuel. The ceramic powders were calcined at 550 Degree-Sign C for 2 h and subsequently heat treated at 1350 Degree-Sign C for 10 min (fast-firing). The X-ray diffraction technique was employed to identify and characterize the crystalline phases present in the synthesized powders, using the Rietveld method. Monophasic nanostructured samples of BaZrO{sub 3} and CaZrO{sub 3} presenting average crystallite sizes of around 8.5 and 10.3 nm, respectively, were found after fast-firing. (author)

  14. Reverse micellar synthesis, structural characterization and dielectric properties of Sr-doped BaZrO{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Tokeer, E-mail: tahmad3@jmi.ac.in [Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi, 110025 (India); Ubaidullah, Mohd [Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi, 110025 (India); Department of Chemistry, Banasthali University, Tonk, Rajasthan, 304022 (India); School of Science and Technology, Glocal University, Mirzapur, Saharanpur, 247121, Uttar Pradesh (India); Shahazad, Mohd [Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi, 110025 (India); Kumar, Dinesh [Department of Chemistry, Banasthali University, Tonk, Rajasthan, 304022 (India); Al-Hartomy, Omar A. [Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah, 21589 (Saudi Arabia)

    2017-01-01

    Sr-doped BaZrO{sub 3} nanoparticles with strontium content varying from 5 to 20 mol % were successfully synthesized by reverse micellar method at 900 °C for the first time. Systematic studies have been carried out to establish the structural and electrical properties of the as prepared nanoparticles. These nanoparticles were characterized using powder X-ray diffraction, transmission electron microscopy, BET surface area and dielectric measurements. X-ray diffraction analysis showed the formation of monophasic and highly crystalline nanoparticles which could be indexed in cubic BaZrO{sub 3} with contraction of lattice on strontium substitution. A monotonic shift of diffraction pattern towards higher angel confirms the formation of solid solutions of Ba{sub 1−x}Sr{sub x}ZrO{sub 3} (0.05 ≤ x ≤ 0.20) which was corroborating well with lattice parameter studies. Transmission electron microscopic studies showed the formation of cubic, spherical and hexagonal nanoparticles with an average grain size of 40–65 nm. Energy dispersive X-ray spectroscopic studies confirmed the presence of dopant (Sr{sup 2+}) in the BaZrO{sub 3} matrix and estimated chemical species corroborate well with the loaded composition. Specific surface area of the solid solution comes out to be in the range of 104–244 m{sup 2} g{sup -1}. Smallest particle of size 40 nm shows highest surface area 244 m{sup 2} g{sup -1} for 20 mol% Sr-doped BaZrO{sub 3}. Dielectric and impedance studies were also carried out as a function of frequency and temperature to explore the electrical properties of Sr-doped BaZrO{sub 3}. The dielectric constant of Ba{sub 1−x}Sr{sub x}ZrO{sub 3} (0.05 ≤ x ≤ 0.20) was found to be in the range of 13–25 for x = 0.05 to x = 0.20 with nearly similar dielectric loss of the order of 0.02. The conductance increases linearly with increase in frequency at room temperature, however the impedance has an inverse effect. - Highlights: • Monophasic nanocrystalline Ba{sub 1

  15. Effect of impregnation of La0.85Sr0.15MnO<sub>3/Yttria Stabilized Zirconia Solid Oxide Fuel Cell cathodes with La0.85Sr0.15MnO<sub>3 or Al2O<sub>3 nano-particles

    DEFF Research Database (Denmark)

    Kammer Hansen, Kent; Wandel, Marie; Liu, Yi-Lin

    2010-01-01

    Strontium substituted lanthanum manganite and yttria stabilized zirconia solid oxide fuel cell composite electrodes were impregnated with nano-particles of strontium substituted lanthanum manganite or alumina. A clear positive effect was observed on low performing electrodes and on good performing...... electrodes if the temperature was kept low after the impregnation with strontium substituted lanthanum manganite. On good performing electrodes the effect disappeared on heating. Alumina nano-particles had a detrimental effect on the activity of the strontium substituted lanthanum manganite based electrodes....

  16. Angular distributions of emitted particles by laser ablation of silver at 355 nm

    DEFF Research Database (Denmark)

    Svendsen, Winnie Edith; Schou, Jørgen; Hansen, T.

    1998-01-01

    The angular distribution of laser ablated silver in vacuum has been measured in situ with an array of quartz-crystal microbalances. The silver surface was irradiated by ns pulses from a Nd:YAG laser operating at 355 nm for fluences ranging from 0.7 J/cm2 to 8 J/cm2. The distribution is strongly...... peaked in the forward direction corresponding to cosp/, where p varies from 5 to 12 for the largest beam spot, but is less peaked for the smallest beam spots. The total collected yield of ablated atoms is about 221015 Ag atoms per pulse for the highest pulse energies....

  17. Photocatalytic hydrogen production over solid solutions between BiFeO{sub 3} and SrTiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Lingwei; Lv, Meilin [Shanghai Key Lab of Chemical Assessment and Sustainability, Department of Chemistry, Tongji University, 1239 Siping Road, Shanghai, 200092 (China); Liu, Gang [Shenyang National laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Science, 72 Wenhua Road, Shenyang 110016 (China); Xu, Xiaoxiang, E-mail: xxxu@tongji.edu.cn [Shanghai Key Lab of Chemical Assessment and Sustainability, Department of Chemistry, Tongji University, 1239 Siping Road, Shanghai, 200092 (China)

    2017-01-01

    Graphical abstract: We have successfully prepared a series of SrTiO{sub 3}-BiFeO{sub 3} solid solutions. These materials own strong visible light absorption and demonstrate appealing photocatalytic activity under both full range and visible light irradiation. - Highlights: • Band gap values can be tuned by adjusting molar ratios between SrTiO{sub 3} and BiFeO{sub 3}. • Photocatalytic activity is greatly improved after constituting solid solutions. • Photocatalytic activity is influenced by surface area and light absorption. • Fe plays an important role for band gap reduction and catalytic activity. - Abstract: Constituting solid solutions has been an appealing means to gain control over various physicochemical properties. In this work, we synthesized a series of SrTiO{sub 3}-BiFeO{sub 3} solid solutions and systematically explored their structural, optical and photocatalytic properties. Our results show that all solid solutions crystallize in a primitive cubic structure and their band gap values can be easily tuned by adjusting molar ratios between SrTiO{sub 3} and BiFeO{sub 3}. Photocatalytic hydrogen production under both full range and visible light irradiation is greatly improved after forming solid solutions. The highest hydrogen production rate obtained is ∼180 μmol/h under full range irradiation (λ ≥ 250 nm) and ∼4.2 μmol/h under visible light irradiation (λ ≥ 400 nm), corresponding to apparent quantum efficiency ∼2.28% and ∼0.10%, respectively. The activity is found to be strongly influenced by surface area and light absorption. Theoretical calculation suggests that Fe contributes to the formation of spin-polarized bands in the middle of original band gap and is responsible for the band gap reduction and visible light photocatalytic activity.

  18. Tuning La{sub 0.67}Sr{sub 0.33}MnO{sub 3} surface magnetism using LaMnO{sub 3} and SrTiO{sub 3} caps

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, L.C. [Department of Materials Science, University of Cambridge, Cambridge CB3 0FS (United Kingdom); Maccherozzi, F. [Diamond Light Source, Chilton, Didcot, Oxfordshire OX11 0DE (United Kingdom); Moya, X. [Department of Materials Science, University of Cambridge, Cambridge CB3 0FS (United Kingdom); Facultat de Física, Departament d' Estructura i Constituents de la Matèria, Universitat de Barcelona, Martí i Franquès 1, E-08028 Barcelona, Catalonia (Spain); Ghidini, M. [Department of Materials Science, University of Cambridge, Cambridge CB3 0FS (United Kingdom); DiFeST, University of Parma, v. le G.P. Usberti 7/A, 43124 Parma (Italy); Yan, W.; Soussi, J. [Department of Materials Science, University of Cambridge, Cambridge CB3 0FS (United Kingdom); Dhesi, S.S. [Diamond Light Source, Chilton, Didcot, Oxfordshire OX11 0DE (United Kingdom); Mathur, N.D., E-mail: ndm12@cam.ac.uk [Department of Materials Science, University of Cambridge, Cambridge CB3 0FS (United Kingdom)

    2014-04-15

    We have investigated how the surface magnetism of epitaxial La{sub 0.67}Sr{sub 0.33}MnO{sub 3} films on NdGaO{sub 3} substrates is modified by 2 nm-thick caps of the undoped manganite LaMnO{sub 3} and the band insulator SrTiO{sub 3}. Low-temperature photoemission electron microscopy images with x-ray magnetic circular dichroism contrast reveal large ferromagnetic domains, and a reduction of surface Curie temperature by 40 K (LaMnO{sub 3} cap) and 70 K (SrTiO{sub 3} cap). We use these negative results to argue that capped films of sub-optimally doped La{sub 1−x}Sr{sub x}MnO{sub 3} (x≠0.33) should improve the operating temperature of all-oxide and other spintronic devices. - Highlights: • LaMnO{sub 3} and SrTiO{sub 3} capping layers modify La{sub 0.67}Sr{sub 0.33}MnO{sub 3} surface magnetism. • Surface Curie temperature is modified with respect to the interior. • XMCD-PEEM images reveal large ferromagnetic domains. • Capped films of non-optimally doped La{sub 1−x}Sr{sub x}MnO{sub 3} may improve spintronic devices.

  19. Synthesis of highly ordered 30 nm NiFe2O4 particles by the microwave-combustion method

    Science.gov (United States)

    Mahmoud, M. H.; Elshahawy, A. M.; Makhlouf, Salah A.; Hamdeh, H. H.

    2014-11-01

    NiFe2O4 of 30 nm average size was synthesized by microwave combustion and subsequent solid state reaction at 1273 K. The materials were characterized by X-ray diffraction, TEM, vibrating sample magnetometery and Mössbauer spectroscopy. The microwave combustion produced materials were comprised chemically of ferrites and a smaller amount of hematite. The NiFe2O4 particles have the cubic spinel structure with crystallites of sizes less than 10 nm, and were found to have low magnetization, and essentially no hysteresis loop; characteristics of superparamagnetism. Upon annealing at temperatures 973 K and below, crystallite growth was accompanied by increase in both coercive field and magnetization. The coercive field was a maximum for the sample annealed at 973 K. On the other hand, crystallite growth at higher annealing temperatures yielded mainly ferrites and improvement in soft magnetic properties. Mössbauer and magnetization measurements indicate that the fine NiFe2O4 particles produced at the annealing temperature of 1273 K are in good chemical and magnetic order, excluding the spins arrangement at the surface of the particles which show spin glass-like behavior.

  20. One step grafting of iron phthalocyanine containing flexible chains on Fe{sub 3}O{sub 4} nanoparticles towards high performance polymer magnetic composites

    Energy Technology Data Exchange (ETDEWEB)

    Pu, Zejun; Zhou, Xuefei; Yang, Xulin; Jia, Kun, E-mail: Jiakun@uestc.edu.cn; Liu, Xiaobo, E-mail: liuxb@uestc.edu.cn

    2015-07-01

    To develop high-performance inorganic particles/polymer composites, the interfacial interaction and dispersion of inorganic particles are the two essential issues to be considered. Herein, we report an effective approach to graft iron phthalocyanine containing flexible chains (NP-ph) on Fe{sub 3}O{sub 4} nanoparticles (NP-ph@Fe{sub 3}O{sub 4}). The hybrids were monodispersed solid nanoparticles with the average diameter of about 250 nm. About 16.8% of the phthalocyanine oligomer was incorporated into the resulting NP-ph@Fe{sub 3}O{sub 4} nanoparticles. The NP-ph@Fe{sub 3}O{sub 4} nanoparticles were subsequently used as the novel filler for preparation of high performance poly(arylene ether nitrile)s (PAEN) composites. The scanning electron microscopy (SEM) investigation showed that the NP-ph@Fe{sub 3}O{sub 4} nanoparticles present better dispersion and interfacial compatibility with PAEN matrix than that of raw Fe{sub 3}O{sub 4}, which was further confirmed by rheological study. Consequently, the improved thermal stability and enhanced mechanical properties were obtained from composites using NP-ph@Fe{sub 3}O{sub 4}. Vibrating sample magnetometer (VSM) results showed that the prepared PAEN composites exhibited higher saturation magnetization and soft magnetic properties. Meanwhile, the saturation magnetization (Ms) of the PAEN/NP-ph@Fe{sub 3}O{sub 4} composite films increased with the increase of the hybrid nanoparticles loading. Thus, the PAEN/NP-ph@Fe{sub 3}O{sub 4} composite would find potential applications in organic magnetic films fields due to their high thermal stability, excellent flexibility and tunable magnetic properties. - Highlights: • An effective approach to graft CuPc containing flexible chains on Fe. • Effect on the mechanical, thermal and interfacial properties were investigated. • The dispersion state was characterized using parallel-plate rheometry. • The mechanism of interfacial compatibility was clarified.

  1. Implementation of Rotational Raman Channel in Multiwavelength Aerosol Lidar to Improve Measurements of Particle Extinction and Backscattering at 532 NM

    Directory of Open Access Journals (Sweden)

    Veselovskii Igor

    2016-01-01

    Full Text Available We describe a practical implementation of rotational Raman (RR measurements in an existing Mie-Raman lidar to obtain measurements of aerosol extinction and backscattering at 532 nm. A 2.3 nm width interference filter was used to select a spectral range characterized by low temperature sensitivity within the anti-Stokes branch of the RR spectrum. Simulations demonstrate that the temperature dependence of the scattering cross section does not exceed 1.0% in the 230-300K range making accurate correction for this dependence quite easy. With this upgrade, the NASA/GSFC multiwavelength Raman lidar has demonstrated useful α532 measurements and was used for regular observations. Examples of lidar measurements and inversion of optical data to the particle microphysics will be given in presentation.

  2. Thermal decomposition of ammonium perchlorate in the presence of Al(OH){sub 3}·Cr(OH){sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, WenJing [Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Ping, E-mail: lipinggnipil@home.ipe.ac.cn [Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Xu, HongBin; Sun, Randi; Qing, Penghui; Zhang, Yi [Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China)

    2014-03-01

    Highlights: • The amorphous Al(OH){sub 3}·Cr(OH){sub 3} nanoparticles containing surface hydroxyls were prepared by a hydrolytic co-precipitation method. • The Al(OH){sub 3}·Cr(OH){sub 3} nanoparticles show excellent catalytic ability for AP decomposition. • The surface hydroxyls and amorphous form of Al(OH){sub 3}·Cr(OH){sub 3} nanoparticles promote ammonia oxidation of AP. - Abstract: An Al(OH){sub 3}·Cr(OH){sub 3} nanoparticle preparation procedure and its catalytic effect and mechanism on thermal decomposition of ammonium perchlorate (AP) were investigated using transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis and differential scanning calorimetry (TG-DSC), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis and mass spectroscopy (TG-MS). In the preparation procedure, TEM, SAED, and FT-IR showed that the Al(OH){sub 3}·Cr(OH){sub 3} particles were amorphous particles with dimensions in the nanometer size regime containing a large amount of surface hydroxyl under the controllable preparation conditions. When the Al(OH){sub 3}·Cr(OH){sub 3} nanoparticles were used as additives for the thermal decomposition of AP, the TG-DSC results showed that the addition of Al(OH){sub 3}·Cr(OH){sub 3} nanoparticles to AP remarkably decreased the onset temperature of AP decomposition from approximately 450 °C to 245 °C. The FT-IR, RS and XPS results confirmed that the surface hydroxyl content of the Al(OH){sub 3}·Cr(OH){sub 3} nanoparticles decreased from 67.94% to 63.65%, and Al(OH){sub 3}·Cr(OH){sub 3} nanoparticles were limitedly transformed from amorphous to crystalline after used as additives for the thermal decomposition of AP. Such behavior of Al(OH){sub 3}·Cr(OH){sub 3} nanoparticles promoted the oxidation of NH{sub 3} of AP to decompose to N{sub 2}O first, as indicated by the TG-MS results, accelerating the AP thermal decomposition.

  3. Solar photocatalytic activity of TiO{sub 2} modified with WO{sub 3} on the degradation of an organophosphorus pesticide

    Energy Technology Data Exchange (ETDEWEB)

    Ramos-Delgado, N.A. [Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, San Nicolás de los Garza, N.L. (Mexico); Gracia-Pinilla, M.A. [Universidad Autónoma de Nuevo León, Facultad de Ciencias Físico-Matemáticas, Av. Universidad, Cd. Universitaria, San Nicolás de los Garza, N.L. (Mexico); Universidad Autónoma de Nuevo León, Centro de Investigación e Innovación en Desarrollo de Ingeniería y Tecnología, PIIT Km 6, Carretera al Aeropuerto, Apodaca, N.L. (Mexico); Maya-Treviño, L.; Hinojosa-Reyes, L.; Guzman-Mar, J.L. [Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, San Nicolás de los Garza, N.L. (Mexico); Hernández-Ramírez, A., E-mail: aracely.hernandezrm@uanl.edu.mx [Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, San Nicolás de los Garza, N.L. (Mexico)

    2013-12-15

    Highlights: • TiO{sub 2} and WO{sub 3}/TiO{sub 2} (2 and 5%) were tested in the photocatalytic malathion degradation. • The use of solar radiation in the photocatalytic degradation process was evaluated. • Modified catalyst showed greater photocatalytic activity than pure TiO{sub 2}. • The mineralization rate was improved when WO{sub 3} content on TiO{sub 2} was 2%. -- Abstract: In this study, the solar photocatalytic activity (SPA) of WO{sub 3}/TiO{sub 2} photocatalysts synthesized by the sol–gel method with two different percentages of WO{sub 3} (2 and 5%wt) was evaluated using malathion as a model contaminant. For comparative purpose bare TiO{sub 2} was also prepared by sol–gel process. The powders were characterized by X-ray diffraction (XRD), Raman spectroscopy, diffuse reflectance UV–vis spectroscopy (DRUV–vis), specific surface area by the BET method (SSA{sub BET}), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy with a high annular angle dark field detector (STEM-HAADF). The XRD, Raman, HRTEM and STEM-HAADF analyses indicated that WO{sub 3} was present as a monoclinic crystalline phase with nanometric cluster sizes (1.1 ± 0.1 nm for 2% WO{sub 3}/TiO{sub 2} and 1.35 ± 0.3 nm for 5% WO{sub 3}/TiO{sub 2}) and uniformly dispersed on the surface of TiO{sub 2}. The particle size of the materials was 19.4 ± 3.3 nm and 25.6 ± 3 nm for 2% and 5% WO{sub 3}/TiO{sub 2}, respectively. The SPA was evaluated on the degradation of commercial malathion pesticide using natural solar light. The 2% WO{sub 3}/TiO{sub 2} photocatalyst exhibited the best photocatalytic activity achieving 76% of total organic carbon (TOC) abatement after 300 min compared to the 5% WO{sub 3}/TiO{sub 2} and bare TiO{sub 2} photocatalysts, which achieved 28 and 47% mineralization, respectively. Finally, experiments were performed to assess 2% WO{sub 3}/TiO{sub 2} catalyst activity on

  4. Magneto-optical and catalytic properties of Fe{sub 3}O{sub 4}@HA@Ag magnetic nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Amir, Md., E-mail: mdamir01031001@gmail.com [Department of Chemistry, Fatih University, 34500 B.Çekmece-İstanbul, Turkey (Turkey); Bio & Nanotechnology Engineering, Faculty of Engineering, Istanbul University, 34452 Beyazıt/Fatih-İstanbul (Turkey); Güner, S. [Department of Physics, Fatih University, 34500 B.Çekmece-İstanbul, Turkey (Turkey); Yıldız, A. [Department of Textile Engineering, Namık Kemal University, 59860 Çorlu-Tekirdağ, Turkey (Turkey); Baykal, A. [Department of Chemistry, Fatih University, 34500 B.Çekmece-İstanbul, Turkey (Turkey)

    2017-01-01

    Fe{sub 3}O{sub 4}@HA@Ag magnetic nanocomposites (MNCs) were successfully synthesized by the simple reflux method for the removal of azo dyes from the industrial aqueous media. Fe{sub 3}O{sub 4}@HA@AgMNCs exhibited high catalytic activity to reduce MB within 20 min from the waste water. The obtained materials were characterized by the means of different techniques. Powder X-ray diffraction (XRD) analysis confirmed the single-phase of Fe{sub 3}O{sub 4} spinel structure. SEM and TEM analysis indicated that Fe{sub 3}O{sub 4}@HA@AgMNCs were nanoparticles like structure with small agglomeration. TG result showed that the products contained 9% of HA. The characteristic peaks of HA at 1601 cm{sup −1} and 1703 cm{sup −1} was observed by the means of FT-IR spectra of Fe{sub 3}O{sub 4}@HA@AgMNCs. The hysteresis (σ–H) curves revealed Fe{sub 3}O{sub 4}@HA@Ag MNCs exhibit a typical superparamagnetic characteristic with a saturation magnetization of 59.11 emu/g and measured magnetic moment is 2.45 µ{sub B}. The average magnetic particle dimension (D{sub mag}) is 13.25 nm. In accordance, the average crystallite and particle dimensions were obtained as 11.50 nm and 13.10 nm from XRD and TEM measurements, respectively. Magnetocrystalline anisotropy was offered as uniaxial and calculated effective anisotropy constant (K{sub eff}) is 2.96×10{sup 5} Erg/g. The blocking temperature was estimated as 522 K. The size-dependent saturation magnetization suggests the existence of a magnetically dead layer as 0.793 nm for Fe{sub 3}O{sub 4}@HA@Ag MNCs. The UV–vis diffuse reflectance spectroscopy (DRS) and Kubelka–Munk theory were applied to determine the optical properties of powder samples. The direct optical energy band gap (E{sub g}) values were estimated from Tauc plots between 1.62 eV and 2.12 eV. - Graphical abstract: An illustration for the fabrication of Fe{sub 3}O{sub 4}@HA@Ag MNCs. - Highlights: • The reduction of azo dye such Methylene Blue was instantly completed with

  5. Solvothermal synthesis of Fe{sub 7}C{sub 3} and Fe{sub 3}C nanostructures with phase and morphology control

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Brent; Clifford, Dustin; Carpenter, Everett E., E-mail: aelgendy@vcu.edu, E-mail: ecarpenter2@vcu.edu [Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284 (United States); El-Gendy, Ahmed A., E-mail: aelgendy@vcu.edu, E-mail: ecarpenter2@vcu.edu [Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284 (United States); Nanotechnology and Nanometrology Laboratory, National Institute for Standards, Giza 12211 (Egypt)

    2016-07-21

    A phase transition, from orthorhombic Fe{sub 3}C to hexagonal Fe{sub 7}C{sub 3}, was observed using a wet synthesis mediated by hexadecyltrimethylammonium chloride (CTAC). In this study, CTAC has been shown to control carbide phase, morphology, and size of the iron carbide nanostructures. Fe{sub 7}C{sub 3} hexagonal prisms were formed with an average diameter of 960 nm, the thickness of 150 nm, and Fe{sub 3}C nanostructures with an approximate size of 50 nm. Magnetic studies show ferromagnetic behavior with M{sub s} of 126 emu/g, and H{sub c} of 170 Oe with respect to Fe{sub 7}C{sub 3} and 95 emu/g and 590 Oe with respect to Fe{sub 3}C. The thermal studies using high temperature x-ray diffraction show stability of Fe{sub 7}C{sub 3} up to 500 °C. Upon slow cooling, the Fe{sub 7}C{sub 3} phase is recovered with an intermediate oxide phase occurring around 300 °C. This study has demonstrated a simple route in synthesizing iron carbides for an in depth magnetic study and crystal phase transition study of Fe{sub 7}C{sub 3} at elevated temperatures.

  6. Formation of carrageenan-CaCO{sub 3} bioactive membranes

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, Lucas F.B.; Maniglia, Bianca C.; Pereira, Lourivaldo S.; Tapia-Blácido, Delia R.; Ramos, Ana P., E-mail: anapr@ffclrp.usp.br

    2016-01-01

    The high biocompatibility and resorbability of polymeric membranes have encouraged their use to manufacture medical devices. Here, we report on the preparation of membranes consisting of carrageenan, a naturally occurring sulfated polysaccharide that forms helical structures in the presence of calcium ions. We incorporated CaCO{sub 3} particles into the membranes to enhance their bioactivity and mechanical properties. Infrared spectroscopy and X-ray diffraction data confirmed CaCO{sub 3} incorporation into the polymeric matrix. We tested the bioactivity of the samples by immersing them in a solution that mimics the ionic composition and pH of the human body fluid. The hybrid membranes generated hydroxyapatite, as attested by X-ray diffraction data. Scanning electron and atomic force microscopies aided investigation of membrane topography before and after CaCO{sub 3} deposition. The wettability and surface free energy, evaluated by contact angle measures, increased in the presence of CaCO{sub 3} particles. These parameters are important for membrane implantation in the body. Moreover, membrane stiffness was up to 110% higher in the presence of the inorganic particles, as revealed by Young's modulus. - Highlights: • Hybrid kappa and iota carrageenan-CaCO{sub 3} membranes were formed. • The hybrid membrane's origin hydroxyapatite after exposure to simulated body fluid • The carrageenan's specificity to bind Ca{sup 2+} ions tailors the surface properties.

  7. Multilayered YBCO/LaAlO{sub 3}/YBCO films for microwave applications

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, C.H.; Dickerson, R.M.; Stan, M.A.; Bhasin, K.B. [National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center

    1994-12-31

    Multilayered YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} (YBCO)/LaAlO{sub 3}/YBCO films deposited on (100)-oriented LaAlO{sub 3} substrates have been studied for potential use in microwave circuits. The thickness of the LaAlO{sub 3} layer was either 100, 300 or 500 nm thick, and the YBCO films were 350 nm. Metallic normal state resistance was observed in the top YBCO layers, but the transition temperature was higher for films deposited on 100 nm LaAlO{sub 3} layers than for films on 300 nm thick LaAlO{sub 3} layers (88 vs. 83 K). Electrical impedance measurements across the dielectric indicate there was extensive shorting between the YBCO layers, and transmission electron microscopy (TEM) micrographs suggests that the shorting occurred along high-angle grain boundaries in the LaAlO{sub 3} film. The LaAlO{sub 3} films grew with columnar structures; at LaAlO{sub 3} thicknesses greater than approximately 150 nm the columns were no longer parallel, and a chevron-shaped structure emerged.

  8. Photocatalytic performance of nano-photocatalyst from TiO{sub 2} and Fe{sub 2}O{sub 3} by mechanochemical synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Ghorai, Tanmay K., E-mail: tanmay_ghorai@yahoo.co.in [Department of Chemistry, West Bengal State University, Barasat, North 24 Pgs, Kolkata 700126 (India); Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India); Chakraborty, Mukut [Department of Chemistry, West Bengal State University, Barasat, North 24 Pgs, Kolkata 700126 (India); Pramanik, Panchanan [Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India)

    2011-08-11

    Graphical abstract: Nano-particles of homogeneous solution between TiO{sub 2} and Fe{sub 2}O{sub 3} (up to 5 mol%) have been prepared by mechanochemical milling. The results show that the alloy of TiO{sub 2} with 5 mol% of Fe{sub 2}O{sub 3} (YFT1) exhibit photocatalytic activity 3-5 times higher than that of P25 TiO{sub 2} for oxidation of various dyes (RB, MO, TB and BG) under visible light irradiation. The average particle size and crystallite size of YFT1 were found to be 30 {+-} 5 nm and 12 nm measured from TEM and XRD. Optical adsorption edge is found to be 2.26 eV. Tentative schematic diagram of reaction mechanism of YFT/RFT photocatalysts under visible light irradiation. Highlights: > Synthesis of nano-sized homogeneous solid solution between Fe{sub 2}O{sub 3} and TiO{sub 2} with high photocatalytic activity for oxidative degradation of different dyes was successfully obtained through mechanochemical synthesis. XRD data shows the formation of solid solution having anatase structure with no free Fe{sub 2}O{sub 3} up to 5 mol% of Fe{sub 2}O{sub 3}. Fe{sub 2}O{sub 3}/TiO{sub 2} catalyst have crystallite size about 12-13 nm measured from XRD and particle size about 30 {+-} 5 nm measured from TEM. FT-IR of all Fe{sub 2}O{sub 3}/TiO{sub 2} prepared catalysts is similar to pure TiO{sub 2}. The maximum solubility of Fe{sub 2}O{sub 3} in TiO{sub 2} is 5 mol% of Fe{sub 2}O{sub 3} irrespective of source and this composition has highest photocatalytic activity that is 3-5 times higher than P25 TiO{sub 2} for the oxidation of different dyes. We also observed that the rate of degradation of Rhodamine B is faster among all the four dyes under prepared catalyst and visible light. - Abstract: Nano-particles of homogeneous solid solution between TiO{sub 2} and Fe{sub 2}O{sub 3} (up to 10 mol%) have been prepared by mechanochemical milling of TiO{sub 2} and yellow Fe{sub 2}O{sub 3}/red Fe{sub 2}O{sub 3}/precipitated Fe (OH){sub 3} using a planetary ball mill. Such novel solid

  9. Investigations of Ba{sub 3}BP{sub 3}O{sub 12}:Eu{sup 2+} single crystal as a scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhi-Jun, E-mail: zhangzj@mail.sic.ac.cn [Key Laboratory of Transparent Opto-Functional Inorganic Materials of Chinese Academy of Sciences, Shanghai Institute of Ceramics, Shanghai 200050 (China); Hu, Guan-Qin; Wang, Hong [Key Laboratory of Transparent Opto-Functional Inorganic Materials of Chinese Academy of Sciences, Shanghai Institute of Ceramics, Shanghai 200050 (China); Zhu, Lin-Lin [Key Laboratory of Transparent Opto-Functional Inorganic Materials of Chinese Academy of Sciences, Shanghai Institute of Ceramics, Shanghai 200050 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Zhao, Jing-Tai [Key Laboratory of Transparent Opto-Functional Inorganic Materials of Chinese Academy of Sciences, Shanghai Institute of Ceramics, Shanghai 200050 (China)

    2014-04-01

    Highlights: • Eu{sup 2+}-activated Ba{sub 3}BP{sub 3}O{sub 12} single crystals have been grown by the top-seeded solution growth method (TSSG) for the first time. • Ba{sub 3}BP{sub 3}O{sub 12}:Eu{sup 2+} single crystal exhibits wide transparency in the wavelength range from 250 to 700 nm. • Ba{sub 3}BP{sub 3}O{sub 12}:Eu{sup 2+} single crystal shows high overall scintillation efficiency (1.8 times of BGO) and moderate decay time (860 ns). - Abstract: Single crystals of Ba{sub 3}BP{sub 3}O{sub 12}:Eu{sup 2+} with high optical quality have been grown by the top-seeded solution growth (TSSG) method using BPO{sub 4}–NaF mixture as the flux. Ba{sub 3}BP{sub 3}O{sub 12}:Eu{sup 2+} single crystal exhibits wide transparency in the wavelength range from 250 to 700 nm, and shows a broad emission band in the wavelength range of 350–650 nm when excited by X-ray radiation. The overall scintillation efficiency is about 1.8 times of that of BGO crystal under the same conditions. Its room temperature fluorescence decay curve exhibits a single-exponent shape with decay time of about 860 ns. It is worth noting that Ba{sub 3}BP{sub 3}O{sub 12}:Eu{sup 2+} single crystal may be of great interest for applications in the field of scintillation materials considering its scintillation properties, as well as the good chemical stability.

  10. Paclitaxel conjugated Fe{sub 3}O{sub 4}@LaF{sub 3}:Ce{sup 3+},Tb{sup 3+} nanoparticles as bifunctional targeting carriers for Cancer theranostics application

    Energy Technology Data Exchange (ETDEWEB)

    Mangaiyarkarasi, Rajendiran; Chinnathambi, Shanmugavel; Karthikeyan, Subramani; Aruna, Prakasarao; Ganesan, Singaravelu, E-mail: sganesan@annauniv.edu

    2016-02-01

    The bi-functional Chitosan functionalized magnetite doped luminescent rare earth nanoparticles (Fe{sub 3}O{sub 4}@LaF{sub 3}: Ce{sup 3+},Tb{sup 3+}/chi NPs) as a carrier of paclitaxel (PTX) drug was designed using a co-precipitation and facile direct precipitation method. The synthesized nanoparticles are spherical in shape with a typical diameter of 19–37 nm respectively. They are water soluble, super paramagnetic and biocompatible, in which the amino groups on the nanoparticles surface are used for the conjugation with an anticancer drug, paclitaxel. The nature of PTX binding with Fe{sub 3}O{sub 4}@LaF{sub 3}: Ce{sup 3+},Tb{sup 3+}/chi nanoparticles were studied using X-ray diffraction, vibrating sample magnetometer and scanning electron micrograph. The nature of interactions between PTX and Fe{sub 3}O{sub 4}@LaF{sub 3}: Ce{sup 3+},Tb{sup 3+}/chi NPs due to complex formation were conceded out by various spectroscopic methods viz., UV–visible, steady state and excited state fluorescence spectroscopy. The photo-physical characterization reveals that the adsorption and release of PTX from Fe{sub 3}O{sub 4}@LaF{sub 3}:Tb{sup 3+}/chi nanoparticles is quicker when compared with other nanoparticles and also confirms that this may be due to the hydrogen bond formation between the hydroxyl group of drug and amino group of nanoparticles respectively. The maximum loading capacity and entrapment efficiency of 83.69% and 80.51% were attained at a ratio of 5:8 of PTX and Fe{sub 3}O{sub 4}@LaF{sub 3}: Ce{sup 3+},Tb{sup 3+}/chi NPs respectively. In addition with that, antitumoral activity study of PTX conjugated Fe{sub 3}O{sub 4}@LaF{sub 3}:Tb{sup 3+}/chi nanoparticles exhibits increased cytotoxic effects on A549 lung cancer cell lines than that of unconjugated PTX. - Highlights: • Fe{sub 3}O{sub 4}@LaF{sub 3}: Ce{sup 3+},Tb{sup 3+}/chi nanoparticles as a carrier of paclitaxel. • These particles are water soluble, super paramagnetic and biocompatible. • The maximum

  11. Surface passivation of Fe{sub 3}O{sub 4} nanoparticles with Al{sub 2}O{sub 3} via atomic layer deposition in a rotating fluidized bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Chen-Long; Deng, Zhang; Cao, Kun [State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074 (China); Yin, Hong-Feng [Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201 (China); Shan, Bin [State Key Laboratory of Material Processing and Die and Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074 (China); Chen, Rong, E-mail: rongchen@mail.hust.edu.cn [State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, School of Optical and Electronic Information, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074 (China)

    2016-07-15

    Iron(II,III) oxide (Fe{sub 3}O{sub 4}) nanoparticles have shown great promise in many magnetic-related applications such as magnetic resonance imaging, hyperthermia treatment, and targeted drug delivery. Nevertheless, these nanoparticles are vulnerable to oxidation and magnetization loss under ambient conditions, and passivation is usually required for practical applications. In this work, a home-built rotating fluidized bed (RFB) atomic layer deposition (ALD) reactor was employed to form dense and uniform nanoscale Al{sub 2}O{sub 3} passivation layers on Fe{sub 3}O{sub 4} nanoparticles. The RFB reactor facilitated the precursor diffusion in the particle bed and intensified the dynamic dismantling of soft agglomerates, exposing every surface reactive site to precursor gases. With the aid of in situ mass spectroscopy, it was found that a thicker fluidization bed formed by larger amount of particles increased the residence time of precursors. The prolonged residence time allowed more thorough interactions between the particle surfaces and the precursor gas, resulting in an improvement of the precursor utilization from 78% to nearly 100%, even under a high precursor feeding rate. Uniform passivation layers around the magnetic cores were demonstrated by both transmission electron microscopy and the statistical analysis of Al mass concentrations. Individual particles were coated instead of the soft agglomerates, as was validated by the specific surface area analysis and particle size distribution. The results of thermogravimetric analysis suggested that 5 nm-thick ultrathin Al{sub 2}O{sub 3} coatings could effectively protect the Fe{sub 3}O{sub 4} nanoparticles from oxidation. The x-ray diffraction patterns also showed that the magnetic core crystallinity of such passivated nanoparticles could be well preserved under accelerated oxidation conditions. The precise thickness control via ALD maintained the saturation magnetization at 66.7 emu/g with a 5 nm-thick Al

  12. The preparation and wide frequency microwave absorbing properties of tri-substituted-bisphthalonitrile/Fe{sub 3}O{sub 4} magnetic hybrid microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Shihua; Xu, Mingzhen; Wei, Junji; Yang, Xulin; Liu, Xiaobo, E-mail: Liuxb@uestc.edu.cn

    2014-01-15

    A novel tri-substituted-bisphthalonitrile/magnetite (TPH/Fe{sub 3}O{sub 4}) magnetic hybrid microspheres were synthesized from tri-substituted-bisphthalonitrile (TPH) and FeCl{sub 3}·6H{sub 2}O via a facile one-step solvent-thermal crystallization route. The morphology and structure of the magnetic hybrid microspheres were monitored by SEM, FTIR and XRD. The results displayed that the as-prepared TPH/Fe{sub 3}O{sub 4} magnetic hybrid microspheres were regular spheres and the average particle size was about 137 nm in a narrow dispersion. Besides, the particle size and size distribution can be controlled by subtle variation of the ratio of TPH to ferric ions in the microspheres. The TPH/Fe{sub 3}O{sub 4} hybrid microspheres maintained good saturation magnetization (58.16 emu g{sup −1}) and novel microwave electromagnetic properties: The dielectric loss was less at low frequency and was multimodal at high frequency; the magnetic loss was enhanced obviously with the increasing amount of TPH. Additionally, the microwave absorption properties were detected, and the results demonstrated that the strong reflection loss (RL) and multimodal bands appeared in the wide frequency for the TPH/Fe{sub 3}O{sub 4} magnetic hybrid microspheres. When the matching thickness was 5.0 mm, the effective RL values of −31 dB, −33 dB and −37 dB were obtained in the wide microwave frequency range from 2 GHz to 16 GHz by adjusting the content of TPH. The wide frequency microwave absorption properties, together with the regular sphere and excellent magnetism, enable TPH/Fe{sub 3}O{sub 4} magnetic hybrid microspheres to be further applied in the areas of functional materials. - Highlights: • TPH/Fe{sub 3}O{sub 4} magnetic hybrid microspheres were regular spheres. • The particle size of TPH/Fe{sub 3}O{sub 4} magnetic hybrid microspheres was about 137 nm. • The best saturation magnetization of TPH/Fe{sub 3}O{sub 4} microspheres was 58.16 emu g{sup −1}. • TPH/Fe{sub 3}O{sub 4

  13. Doping nano-Co{sub 3}O{sub 4} surface with bigger nanosized Ag and its photocatalytic properties for visible light photodegradation of organic dyes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Guangliang, E-mail: glchen@zstu.edu.cn [Key Laboratory of Advanced Textile Materials and Manufacturing Technology, and Engineering Research Center for Eco-Dyeing and Finishing of Textiles, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Si, Xiaolei [Key Laboratory of Advanced Textile Materials and Manufacturing Technology, and Engineering Research Center for Eco-Dyeing and Finishing of Textiles, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Yu, Jinsong [Department of Chemistry and Chemical Engineering, University of New Haven, 300 Boston Post Road, West Haven, CT 06516 (United States); Bai, Huiyu [The Key Laboratory of Food Colloids and Biotechnology, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi, Jiangsu 214122 (China); Zhang, Xianhui [Fujian Provincial key Laboratory of Plasma and Magnetic Resonance, School of Physics and Mechanical & Electrical Engineering, Xiamen University, Xiamen, Fujian 361005 (China)

    2015-03-01

    Highlights: • Bigger Co{sub 3}O{sub 4} nanoflake was fabricated with a traditional hydrothermal method. • The Co{sub 3}O{sub 4} nanoflake surface doped with nanosized Ag by a simple silver-mirror reaction. • The bigger Ag particles (>10 nm) also enhanced the catalytic activity of Co{sub 3}O{sub 4}. - Abstract: This paper reports the synthesis of nanosized Ag/Co{sub 3}O{sub 4} composite catalysts using a silver-mirror reaction and the calibration of their catalytic activities towards methyl blue (MB) dye degradation with peroxymonosulfate (PMS) under visible light. The nanosized Ag/Co{sub 3}O{sub 4} composites were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV–vis spectroscopy. The experimental evidence indicated that the hydrothermal synthesis approach lead to the exposure of the {1 1 2} facets of the Co{sub 3}O{sub 4} nanoflakes. Compared to Co{sub 3}O{sub 4} nanoflakes, Co{sub 3}O{sub 4} doped with Ag nanoparticle (average diameters of 10–15 nm) presented lower band gap energy and photoluminescent (PL) intensity. Meanwhile, the Ag/Co{sub 3}O{sub 4} exhibited high stability and excellent dispersion property in dye solution. Experimental data suggested that 3.06 wt% Ag nanoparticle-doped Ag/Co{sub 3}O{sub 4} nanocomposite catalyst possessed the highest catalytic activity towards MB degradation in aqueous solution at the tested concentration level of 15 mg/L, about 2.4 times higher than that of pure Co{sub 3}O{sub 4}. Complete decolorization of the 15 mg/L MB solution can be achieved by 3.06 wt% Ag-doped Ag/Co{sub 3}O{sub 4} nanocomposite within 20 min of visible light irradiation.

  14. UV exposure and photon degradation of Alq{sub 3} powders

    Energy Technology Data Exchange (ETDEWEB)

    Duvenhage, M.M.; Ntwaeaborwa, O.M. [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA9300 (South Africa); Swart, H.C., E-mail: swarthc@ufs.ac.za [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA9300 (South Africa)

    2012-05-15

    Tris-(8-hydroxyquinoline)aluminum (Alq{sub 3}) is a widely used light emitting material. It is also used as an electron transporting layer in organic light emitting devices (OLEDs). Degradation is, however, a major problem in these devices. The device performance is affected by parameters such as air, moisture and light exposure. In this work the effect of photon degradation of Alq{sub 3} in air is investigated. Alq{sub 3} phosphor powder was synthesized using a co-precipitation method and recrystalized in acetone. The structure of the sample was determined by using x-ray diffraction (XRD). The averaging particle size estimated from the broadened XRD peaks using Scherrer's equation was 40{+-}4 nm in diameter. The excitation photoluminescence data that was collected correspond well to the absorption data. To study the photon degradation, the sample was irradiated with an UV lamp for {approx}330h. The emission data was collected and the change in photoluminescence intensity with time was monitored.

  15. A pyrene-benzthiazolium conjugate portraying aggregation induced emission, a ratiometric detection and live cell visualization of HSO{sub 3}{sup −}

    Energy Technology Data Exchange (ETDEWEB)

    Diwan, Uzra; Kumar, Virendra [Department of Chemistry (Centre of Advanced Study), Faculty of Science, Banaras Hindu University, Varanasi, Uttar Pradesh 221005 (India); Mishra, Rakesh K. [Photosciences and Photonics, Chemical Sciences and Technology Division, CSIR–National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019 (India); Rana, Nishant Kumar; Koch, Biplob; Singh, Manish Kumar [Department of Zoology (Centre of Advanced Study), Faculty of Science, Banaras Hindu University, Varanasi 221005 (India); Upadhyay, K.K., E-mail: drkaushalbhu@yahoo.co.in [Department of Chemistry (Centre of Advanced Study), Faculty of Science, Banaras Hindu University, Varanasi, Uttar Pradesh 221005 (India)

    2016-07-27

    The present study deals with the photophysical property of a pyrene-benzthiazolium conjugate R1, as a strong intramolecular charge transfer (ICT) probe exhibiting long wavelength emission in the red region. Unlike traditional planar polyaromatic hydrocarbons whose aggregation generally quenches the light emission, the pyrene based R1 was found to display aggregation-induced emission (AIE) property along with simultaneous increase in its quantum yield upon increasing the water content of the medium. The R1 exhibits high specificity towards HSO{sub 3}{sup −}/SO{sub 3}{sup 2−} by interrupting its own ICT producing there upon a large ratiometric blue shift of ∼220 nm in its emission spectrum. The lowest detection limit for the above measurement was found to be 8.90 × 10{sup −8} M. The fluorescent detection of HSO{sub 3}{sup −} was also demonstrated excellently by test paper strip and silica coated TLC plate incorporating R1. The live cell imaging of HSO{sub 3}{sup −} through R1 in HeLa cells was studied using fluorescence microscopic studies. The particle size and morphological features of R1 and R1-HSO{sub 3}{sup −} aggregates in aqueous solution were characterized by DLS along with SEM analysis.- Highlights: • A pyrene-benzthiazolium conjugate probe (R1) itself showed interesting phenomenon of an aggregation-induced emission (AIE). • R1 emits in the red channel and effectively utilized as a colorimetric and ratiometric fluorescent sensor for HSO{sub 3}{sup −}. • The nano-dimensional spherical particles of R1 got enlarged upon its interaction with the HSO{sub 3}{sup −}. • R1 can efficiently stain HSO{sub 3}{sup −} in live cells and can be used for the on-spot detection of the same.

  16. Effect of pH variation on the stability and structural properties of In(OH){sub 3} nanoparticles synthesized by co-precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Goh, Kian Wei; Wong, Yew Hoong [University of Malaya, Department of Mechanical Engineering, Faculty of Engineering, Kuala Lumpur (Malaysia); Johan, Mohd Rafie [University of Malaya, Department of Mechanical Engineering, Faculty of Engineering, Kuala Lumpur (Malaysia); University of Malaya, Nanotechnology and Catalysis Research Centre, Kuala Lumpur (Malaysia)

    2016-10-15

    Indium hydroxide (In(OH){sub 3}) nanoparticles were synthesized at various pH values (8-11) by co-precipitation method. Its properties were characterized by X-ray diffractometer, Fourier transform infrared spectroscopy, Raman spectroscopy and transmission electron microscope. The electrostatic stability of nanoparticles is carried out through zeta potential measurement. The crystallite size of nanoparticles calculated by Scherrer equation has similar trend with the values obtained from William-Hall plot. TEM images show that the particles size is within the range of 11.76-20.76 nm. The maximum zeta potential is 3.68 mV associated with the smallest particle size distribution of 92.6 nm occurred at pH 10. Our work clearly confirms the crystallite size, stability and the morphology of In(OH){sub 3} NPs are strongly depending on the pH of precursor solution. (orig.)

  17. Using a SMALP platform to determine a sub-nm single particle cryo-EM membrane protein structure.

    Science.gov (United States)

    Parmar, Mayuriben; Rawson, Shaun; Scarff, Charlotte A; Goldman, Adrian; Dafforn, Timothy R; Muench, Stephen P; Postis, Vincent L G

    2018-02-01

    The field of membrane protein structural biology has been revolutionized over the last few years with a number of high profile structures being solved using cryo-EM including Piezo, Ryanodine receptor, TRPV1 and the Glutamate receptor. Further developments in the EM field hold the promise of even greater progress in terms of greater resolution, which for membrane proteins is still typically within the 4-7Å range. One advantage of a cryo-EM approach is the ability to study membrane proteins in more "native" like environments for example proteoliposomes, amphipols and nanodiscs. Recently, styrene maleic acid co-polymers (SMA) have been used to extract membrane proteins surrounded by native lipids (SMALPs) maintaining a more natural environment. We report here the structure of the Escherichia coli multidrug efflux transporter AcrB in a SMALP scaffold to sub-nm resolution, with the resulting map being consistent with high resolution crystal structures and other EM derived maps. However, both the C-terminal helix (TM12) and TM7 are poorly defined in the map. These helices are at the exterior of the helical bundle and form the greater interaction with the native lipids and SMA polymer and may represent a more dynamic region of the protein. This work shows the promise of using an SMA approach for single particle cryo-EM studies to provide sub-nm structures. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  18. Effects of decreasing activated carbon particle diameter from 30 μm to 140 nm on equilibrium adsorption capacity.

    Science.gov (United States)

    Pan, Long; Nishimura, Yuki; Takaesu, Hideki; Matsui, Yoshihiko; Matsushita, Taku; Shirasaki, Nobutaka

    2017-11-01

    The capacity of activated carbon particles with median diameters (D50s) of >∼1 μm for adsorption of hydrophobic micropollutants such as 2-methylisolborneol (MIB) increases with decreasing particle size because the pollutants are adsorbed mostly on the exterior (shell) of the particles owing to the limited diffusion penetration depth. However, particles with D50s of adsorption capacities for MIB and several other environmentally relevant adsorbates. The adsorption capacities for low-molecular-weight adsorbates, including MIB, deceased with decreasing particle size for D50s of less than a few micrometers, whereas adsorption capacities increased with decreasing particle size for larger particles. The oxygen content of the particles increased substantially with decreasing particle size for D50s of less than a few micrometers, and oxygen content was negatively correlated with adsorption capacity. The decrease in adsorption capacity with decreasing particle size for the smaller particles was due to particle oxidation during the micromilling procedure used to decrease D50 to ∼140 nm. When oxidation was partially inhibited, the MIB adsorption capacity decrease was attenuated. For high-molecular-weight adsorbates, adsorption capacity increased with decreasing particle size over the entire range of tested particle sizes, even though particle oxygen content increased with decreasing particle size. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Study of magnetic behavior in hexagonal-YMn{sub 1−x}Fe{sub x}O{sub 3} (x=0 and 0.2) nanoparticles using remanent magnetization curves

    Energy Technology Data Exchange (ETDEWEB)

    Chauhan, Samta; Singh, Amit Kumar; Srivastava, Saurabh Kumar; Chandra, Ramesh, E-mail: ramesfic@iitr.ac.in

    2016-09-15

    We have studied the magnetic behavior of YMn{sub 1−x}Fe{sub x}O{sub 3} (x=0 and 0.2) nanoparticles synthesized by conventional solid state reaction method. The as-synthesized nanoparticles were found to have hexagonal phase with P6{sub 3cm} space group confirmed by X-Ray diffraction. The particle size was found to be ~70 nm as confirmed by both X-Ray diffraction and Transmission Electron Microscopy. DC magnetization and memory effect measurements imply that the h-YMnO{sub 3} nanoparticles bear a resemblance to super spin-glass state following de Almeida–Thouless like behavior which is being suppressed by Fe-doping. The Fe-doping in YMnO{sub 3} enhances the antiferromagnetic (AFM) transition temperature T{sub N} to ~79 K and induces a new magnetic state due to the surface spins which is realized as diluted antiferromagnet in a field (DAFF) as explored by the thermoremanent and isothermoremanent magnetization measured with different applied magnetic field. - Highlights: • Magnetic behavior of h-YMn{sub 1−x}Fe{sub x}O{sub 3} (x=0 and 0.2) nanoparticles have been studied. • The nanoparticles (~70 nm) were synthesized by solid state reaction method. • Magnetic data reveal spin-glass behavior in YMnO{sub 3} which was suppressed in YMn{sub 0.8}Fe{sub 0.2}O{sub 3}. • The h-YMnO{sub 3} nanoparticles show memory effect and obey de-Almeida Thouless line. • TRM and IRM suggest spin glass nature for YMnO{sub 3}, while the YMn{sub 0.8}Fe{sub 0.2}O{sub 3} resembles DAFF.

  20. Optical features of Ca{sub 4}NdO(BO{sub 3}){sub 3}:Yb single crystals under CW laser illumination

    Energy Technology Data Exchange (ETDEWEB)

    Wojciechowski, A. [Electrical Engineering Department, Czestochowa Technological University, Armii Krajowej Av. 17/19, Czestochowa (Poland); Swirkowicz, M.; Karas, A. [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland); Jaroszewicz, L.R.; Majchrowski, A. [Institute of Applied Physics, Military University of Technology, Gen. Sylwestra Kaliskiego 2, 00-908 Warsaw (Poland); Gondek, E. [Institute of Physics, Cracow University of Technology, Podchorazych St. 1, Cracow 30-084 (Poland); Ozga, K. [Public Health, Czestochowa Technological University, Armii Krajowej Av. 36B, 42-200 Czestochowa (Poland); Kityk, I.V., E-mail: ikityk@el.pcz.czest.p [Electrical Engineering Department, Czestochowa Technological University, Armii Krajowej Av. 17/19, Czestochowa (Poland)

    2010-08-13

    Optical treatment of Ca{sub 4}NdO(BO{sub 3}){sub 3}:Yb under continuous laser illumination at different wavelengths led to substantial changes of optical absorption and optical second harmonic generation. The treatment was performed successively by infrared (780 nm), red (650 nm), green (532 nm) and blue (405 nm) laser wavelengths with powers varying within the 200-400 mW range. We demonstrated enhancement of the optical second harmonic generation in the Ca{sub 4}NdO(BO{sub 3}){sub 3}:Yb (1.9% in weighting unit) crystals under the influence of the green cw laser at 532 nm. The principal changes were observed after 15 min of the treatment. A correlation between the occurrence of the hyperfine structure in the absorption spectra and the enhancement of the optical second harmonic generation was found. The additional treatment by the blue laser led to disappearance of appeared photo-induced changes of absorption and decrease of the optical second harmonic generation. It is principal that the effect is non-reversible in time and it does not depend on the photo-inducing light polarization. The principal origin of the observed photo-induced optical second harmonic generation is photo-polarization of the particular rare earth localized levels and formation of the stable polarized states due to the presence of Yb ions, playing crucial role. No such effects were observed in pure Ca{sub 4}NdO(BO{sub 3}){sub 3}.

  1. Synthesis and photoluminescence properties of Pb{sup 2+} doped inorganic borate phosphor NaSr{sub 4}(BO{sub 3}){sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Chauhan, A. O., E-mail: abhi2718@gmail.com; Koparkar, K. A.; Omanwar, S. K. [Department of Physics, SantGadge Baba Amravati University, Amravati MH, 444602 (India); Bajaj, N. S. [Department of Physics, Toshniwal Art, Commerce and Science College, Sengoan, Hingoli MH (India)

    2016-05-06

    A series of Inorganic borate phosphors NaSr{sub 4}(BO{sub 3}){sub 3} doped with Pb{sup 2+} was successfully synthesized by modified solid state diffusion method. The crystal structure and the phase purity of sample were characterized by powder X-ray diffraction (XRD). The photoluminescence properties of synthesized materials were investigated using spectrofluorometer at room temperature. The phosphor show strong broad band emission spectra in UVA region maximum at 370 nm under the excitation of 289 nm. The dependence of the emission intensity on the Pb{sup 2+} concentration for the NaSr{sub 4}(BO{sub 3}){sub 3} were studied in details. The concentration quenching of Pb{sup 2+} doped NaSr{sub 4}(BO{sub 3}){sub 3} was observed at 0.02 mol. The Stokes shifts of NaSr{sub 4}(BO{sub 3}){sub 3}: Pb{sup 2+} phosphor was calculated to be 7574 cm{sup −1}.

  2. Large electron concentration modulation using capacitance enhancement in SrTiO{sub 3}/SmTiO{sub 3} Fin-field effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Amit, E-mail: averma@cornell.edu; Nomoto, Kazuki [Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States); School of Electrical and Computer Engineering, Cornell University, Ithaca, New York 14853 (United States); Hwang, Wan Sik [Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Department of Materials Engineering, Korea Aerospace University, Goyang City, Gyeonggi-do 412791 (Korea, Republic of); Raghavan, Santosh; Stemmer, Susanne [Materials Department, University of California, Santa Barbara, California 93106 (United States); Jena, Debdeep [Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States); School of Electrical and Computer Engineering, Cornell University, Ithaca, New York 14853 (United States); Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853 (United States)

    2016-05-02

    Solid-state modulation of 2-dimensional electron gases (2DEGs) with extreme (∼3.3 × 10{sup 14 }cm{sup −2}) densities corresponding to 1/2 electron per interface unit cell at complex oxide heterointerfaces (such as SrTiO{sub 3}/GdTiO{sub 3} or SrTiO{sub 3}/SmTiO{sub 3}) is challenging because it requires enormous gate capacitances. One way to achieve large gate capacitances is by geometrical capacitance enhancement in fin structures. In this work, we fabricate both Au-gated planar field effect transistors (FETs) and Fin-FETs with varying fin-widths on 60 nm SrTiO{sub 3}/5 nm SmTiO{sub 3} thin films grown by hybrid molecular beam epitaxy. We find that the FinFETs exhibit higher gate capacitance compared to planar FETs. By scaling down the SrTiO{sub 3}/SmTiO{sub 3} fin widths, we demonstrate further gate capacitance enhancement, almost twice compared to the planar FETs. In the FinFETs with narrowest fin-widths, we demonstrate a record 2DEG electron concentration modulation of ∼2.4 × 10{sup 14 }cm{sup −2}.

  3. Electronic structure of Ni/sub 3/Al and Ni/sub 3/Ga alloys

    CERN Document Server

    Pong, W F; Chang, Y K; Tsai, M H; Hsieh, H H; Pieh, J Y; Tseng, P K; Lee, J F; Hsu, L S

    1999-01-01

    This work investigates the charge transfer and Al(Ga) p-Ni d hybridization effects in the intermetallic Ni/sub 3/Al(Ni/sub 3/Ga) alloy using the NiL/sub 3.2/- and K-edge and Al(Ga)K X-ray absorption near edge structure (XANES) measurements. We find that the intensity of white-line features at the NiL/sub 3.2/-edge in the Ni/sub 3/Al(Ni /sub 3/Ga) alloy decreased in comparison with that of pure Ni, which can be attributed to the enhancement of Ni3d states filling and the depletion of the density of Ni 3d unoccupied states in the Ni/sub 3 /Al(Ni/sub 3/Ga) alloy. Two clear features are also observed in the Ni/sub 3/Al(Ni/sub 3/Ga) XANES spectrum at the Al(Ga) K-edge, which can be assigned to the Al(Ga) unoccupied 3p (4p) states and their hybridized states with the Ni 3d/4sp states above the Fermi level in Ni/sub 3/Al(Ni/sub 3/Ga). The threshold at Al K-edge XANES for Ni/sub 3/Al clearly shifts towards higher photon energies relative to that of pure Al, indicating that Al loses charges upon forming Ni/sub 3 /Al. ...

  4. Calcination temperature influenced multiferroic properties of Ca-doped BiFeO{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Dhir, Gitanjali, E-mail: gitanjali.thaprian@gmail.com; Uniyal, Poonam; Verma, N. K. [Nano Research Lab, School of Physics and Materials Science, Thapar University, Patiala-147004 (India)

    2015-06-24

    The influence of Ca-doping and particle size on structural, morphological and magnetic properties of BiFeO{sub 3} nanoparticles has been studied. A sol-gel method was employed for the synthesis of nanoparticles and their particle size was tailored by varying the calcination temperature. Structural analysis revealed a rhombohedral distortion induced by Ca-substitution. The broadening of diffraction peaks with decreasing calcination temperature was indicative of reduction in crystallite size. The morphological analysis revealed the formation of agglomerated nanoparticles having average particle size ranging from 10-15 and 50-55 nm for C4 and C6, respectively. The agglomeration is attributed to high surface energy of nanoparticles. Ferromagnetism has been displayed by all the synthesized nanoparticles. Enhancement of saturation magnetization with Ca-substitution is attributed to suppression of spin cycloid structure by the reduction in size, lattice distortion and creation of oxygen vacancies by the substitution of divalent ion at trivalent site. Further, this value increases as a function of decreasing particle size. Strong particle size effects on magnetic properties of the synthesized nanoparticles are owed to increasing surface to volume ratio. All these observations are indicative of strong dependence of multiferroism on particle size.

  5. Comparative study of cylindrical and parallel-plate electrophoretic separations for the removal of ions and sub-23 nm particles.

    Science.gov (United States)

    Yu, Tongzhu; Yang, Yixin; Liu, Jianguo; Gui, Huaqiao; Zhang, Jiaoshi; Cheng, Yin; Wang, Wenyu; Du, Peng; Wang, Jie; Wang, Huanqin

    2017-12-01

    Cylindrical and parallel-plate electrophoretic separations for the removal of ions and sub-23 nm particles were compared in this study. First, COMSOL Multiphysics® software was utilized to simulate the ion and particle trajectories inside both electrophoretic separations. The results show that ions and sub-23 nm particles are removed simultaneously and that all particles can pass through both electrophoretic separations smoothly at a trap voltage of 25 V. The experimental results show that ion losses become smaller with increasing ion flow rates, and ion losses of the cylindrical and parallel-plate electrophoretic separations range from 56.2 to 71.6% and from 43.8 to 59.6%, respectively, at ion flow rates ranging from 1-3 L/min. For the removal of ions and sub-23 nm particles, the collection efficiency of both electrophoretic separations can reach 100%, but the parallel-plate electrophoretic separation requires a lower trap voltage. The particle loss of the parallel-plate electrophoretic separation is under approximately 10%, which is lower than that of the cylindrical electrophoretic separation. In particular, for large particles (800-2500 nm), the particle losses inside the cylindrical electrophoretic separation are approximately two times higher than those inside the parallel-plate electrophoretic separation. The parallel-plate electrophoretic separation is beneficial for the removal of ions and sub-23 nm particles. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. High resolution electron energy loss spectroscopy of manganese oxides: Application to Mn{sub 3}O{sub 4} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Laffont, L., E-mail: Lydia.laffont@ensiacet.fr [Institut Carnot, Laboratoire CIRIMAT (equipe MEMO), CNRS UMR 5085, ENSIACET, 4 allee Emile Monso, BP 74233, 31432 Toulouse cedex 4 (France); Gibot, P. [Laboratoire de Reactivite et Chimie des Solides CNRS UMR 6007, Universite de Picardie Jules Verne, 33 rue Saint Leu, 80039 Amiens cedex 9 (France)

    2010-11-15

    Manganese oxides particularly Mn{sub 3}O{sub 4} Hausmannite are currently used in many industrial applications such as catalysis, magnetism, electrochemistry or air contamination. The downsizing of the particle size of such material permits an improvement of its intrinsic properties and a consequent increase in its performances compared to a classical micron-sized material. Here, we report a novel synthesis of hydrophilic nano-sized Mn{sub 3}O{sub 4}, a bivalent oxide, for which a precise characterization is necessary and for which the determination of the valency proves to be essential. X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and particularly High Resolution Electron Energy Loss Spectroscopy (HREELS) allow us to perform these measurements on the nanometer scale. Well crystallized 10-20 nm sized Mn{sub 3}O{sub 4} particles with sphere-shaped morphology were thus successfully synthesized. Meticulous EELS investigations allowed the determination of a Mn{sup 3+}/Mn{sup 2+} ratio of 1.5, i.e. slightly lower than the theoretical value of 2 for the bulk Hausmannite manganese oxide. This result emphasizes the presence of vacancies on the tetrahedral sites in the structure of the as-synthesized nanomaterial. - Research Highlights: {yields}Mn{sub 3}O{sub 4} bulk and nano were studied by XRD, TEM and EELS. {yields}XRD and TEM determine the degree of crystallinity and the narrow grain size. {yields}HREELS gave access to the Mn{sup 3+}/Mn{sup 2+} ratio. {yields}Mn{sub 3}O{sub 4} nano have vacancies on the tetrahedral sites.

  7. Electrocatalysis of oxygen reduction on Cu{sub x}Mn{sub 3-x}O{sub 4} (1.0 {<=} x {<=} 1.4) spinel particles/polypyrrole composite electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Rios, E.; Abarca, S.; Daccarett, P.; Gautier, J.L. [Laboratorio de Fisicoquimica y Electroquimica de Solidos, Departamento de Quimica de los Materiales, Facultad de Quimica y Biologia, Universidad de Santiago de Chile, Av. L. B. O' Higgins 3363, Santiago (Chile); Nguyen Cong, H.; Martel, D. [Laboratoire commun au CNRS et a l' Universite Louis Pasteur, LC 3, UMR 7177,1-4 rue Blaise Pascal, 67000 Strasbourg (France); Marco, J.F.; Gancedo, J.R. [Instituto de Quimica-Fisica ' ' Rocasolano' ' , CSIC, c/Serrano, 119, 28006 Madrid (Spain)

    2008-10-15

    Spinel-type binary transition metal oxides of copper and manganese with composition Cu{sub x}Mn{sub 3-x}O{sub 4} (with x = 1.0; 1.1; 1.2; 1.3 and 1.4) were prepared in powder forms by thermal decomposition of nitrate precursors at different temperatures. Their structural properties have been examined by X-ray powder diffraction (XRD), oxidation power and X-ray Photoelectron Spectroscopy (XPS) measurements. To study the effects of solid state properties of the spinel-type compounds on their electrocatalytic activity for the oxygen reduction reaction (orr) in aqueous KCl-KOH solutions, the cathodic polarization characteristics were investigated on composite electrodes of copper and manganese spinel-type oxides nanoparticles embedded in an electrically conductive polymer. These electrodes consisted of multilayered composite electrodes on conductive glass (CG), having the structure CG/PPy/PPy (Ox)/PPy, where PPy is the polypyrrole and Ox is a mixed valence oxide with the general composition Cu{sub x}Mn{sub 3-x}O{sub 4} (1.0 {<=} x {<=} 1.4). The data have shown that the substitution of Mn by Cu increases the catalytic activity, the maximum being that exhibited by Cu{sub 1.4}Mn{sub 1.6}O{sub 4}. Correlations between solid state chemistry and electrocatalytical reactivities towards the oxygen reduction reaction in alkaline media were also investigated on the composite powder electrodes of Cu{sub x}Mn{sub 3-x}O{sub 4} (1.0 {<=} x {<=} 1.4). The results have indicated that the copper content promotes not only the Mn{sup 4+} formation but also the increase of the Mn{sup 4+}/Mn{sup 3+} relation. The change of the Mn{sup 4+}/Mn{sup 3+} ratio as a function of x has been correlated to the electrocatalytical parameters of the orr. The enhanced activity that is observed is related to the higher occurrence of the Mn{sup 4+}/Mn{sup 3+} solid state redox couple in octahedral sites. (author)

  8. Structural, spectroscopic and cytotoxicity studies of TbF{sub 3}@CeF{sub 3} and TbF{sub 3}@CeF{sub 3}@SiO{sub 2} nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Grzyb, Tomasz; Runowski, Marcin [Adam Mickiewicz University, Department of Rare Earths, Faculty of Chemistry (Poland); Dabrowska, Krystyna [Polish Academy of Sciences, Bacteriophage Laboratory, Institute of Immunology and Experimental Therapy (Poland); Giersig, Michael; Lis, Stefan, E-mail: blis@amu.edu.pl [Adam Mickiewicz University, Department of Rare Earths, Faculty of Chemistry (Poland)

    2013-10-15

    Terbium fluoride nanocrystals, covered by a shell, composed of cerium fluoride were synthesized by a co-precipitation method. Their complex structure was formed spontaneously during the synthesis. The surface of these core/shell nanocrystals was additionally modified by silica. The properties of TbF{sub 3}@CeF{sub 3} and TbF{sub 3}@CeF{sub 3}@SiO{sub 2} nanocrystals, formed in this way, were investigated. Spectroscopic studies showed that the differences between these two groups of products resulted from the presence of the SiO{sub 2} shell. X-ray diffraction patterns confirmed the trigonal crystal structure of TbF{sub 3}@CeF{sub 3} nanocrystals. High resolution transmission electron microscopy in connection with energy-dispersive X-ray spectroscopy showed a complex structure of the formed nanocrystals. Crystallized as small discs, 'the products', with an average diameter around 10 nm, showed an increase in the concentration of Tb{sup 3+} ions from surface to the core of nanocrystals. In addition to photo-physical analyses, cytotoxicity studies were performed on HSkMEC (Human Skin Microvascular Endothelial Cells) and B16F0 mouse melanoma cancer cells. The cytotoxicity of the nanomaterials was neutral for the investigated cells with no toxic or antiproliferative effect in the cell cultures, either for normal or for cancer cells. This fact makes the obtained nanocrystals good candidates for biological applications and further modifications of the SiO{sub 2} shell.Graphical Abstract.

  9. Synergistic photocatalysis of Cr(VI) reduction and 4-Chlorophenol degradation over hydroxylated α-Fe{sub 2}O{sub 3} under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ji-Chao; Ren, Juan [College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450002 (China); Yao, Hong-Chang, E-mail: yaohongchang@zzu.edu.cn [College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450002 (China); Zhang, Lin; Wang, Jian-She; Zang, Shuang-Quan [College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450002 (China); Han, Li-Feng [Henan Provincial Key Laboratory of Surface & Interface Science, Zhengzhou University of Light Industry, Zhengzhou 450002 (China); Li, Zhong-Jun, E-mail: lizhongjun@zzu.edu.cn [College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450002 (China)

    2016-07-05

    Highlights: • The surface hydroxyl of Fe{sub 2}O{sub 3} influences on the Cr(VI) reduction activity. • The synergistic photocatalysis enhances degradation activity of Cr(VI) and 4-CP. • The Fe{sub 2}O{sub 3} catalyst exhibits good stability and degradation activity after 9 runs. - Abstract: A series of Fe{sub 2}O{sub 3} materials with hydroxyl are synthesized in different monohydric alcohol (C{sub 2} – C{sub 5}) solvents by solvothermal method and characterized by XRD, BET, XPS, TG and EA. The amount of hydroxyl is demonstrated to be emerged on the surface of the as-synthesized Fe{sub 2}O{sub 3} particles and their contents are determined to be from 7.99 to 3.74 wt%. The Cr(VI) reduction experiments show that the hydroxyl content of Fe{sub 2}O{sub 3} samples exacts great influence on the photocatalytic activity under visible light irradiation (λ > 400 nm) and that the Fe{sub 2}O{sub 3} sample synthesized in n-butyl alcohol exhibits the optimal photocatalytic activity. The synergistic photocatalysis for 4-Chlorophenol (4-CP) degradation and Cr(VI) reduction over above Fe{sub 2}O{sub 3} sample is further investigated. The photocatalytic ratio of Cr(VI) reduction are enhanced from 24.8% to 70.2% while that of 4-CP oxidation are increased from 13.5% to 47.8% after 1 h visible light irradiation. The Fe{sub 2}O{sub 3} sample keeps good degradation rates of mixed pollutants after 9 runs. The active oxygen intermediates O{sub 2}{sup −}·, ·OH and H{sub 2}O{sub 2} formed in the photoreaction process are discovered by ESR measurement and UV–vis test. The photocatalytic degradation mechanism is proposed accordingly.

  10. FORMATION OF N{sub 3}, CH{sub 3}, HCN, AND HNC FROM THE FAR-UV PHOTOLYSIS OF CH{sub 4} IN NITROGEN ICE

    Energy Technology Data Exchange (ETDEWEB)

    Lo, Jen-Iu; Chou, Sheng-Lung; Peng, Yu-Chain; Lin, Meng-Yeh; Lu, Hsiao-Chi; Cheng, Bing-Ming, E-mail: bmcheng@nsrrc.org.tw [National Synchrotron Radiation Research Center, No. 101, Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan (China)

    2015-11-15

    The irradiation of pure solid N{sub 2} at 3 K with far-ultraviolet light from a synchrotron produced infrared absorption lines at 1657.7, 1655.6, and 1652.4 cm{sup −1} and an ultraviolet absorption line at 272.0 nm, which are characteristic of the product N{sub 3}. The threshold wavelength at which N{sub 3} was generated was 145.6 ± 2.9 nm, corresponding to an energy of 8.52 ± 0.17 eV. The photolysis of isotopically labeled {sup 15}N{sub 2} at 3 K consistently led to the formation of {sup 15}N{sub 3} with the same threshold wavelength of 145.6 ± 2.9 nm for its formation. The photolysis of CH{sub 4} in nitrogen ice in low concentrations also led to the formation of N{sub 3}, together with CH{sub 3}, HCN, and HNC, with the same threshold wavelength of 145.6 ± 2.9 nm. These results indicate that N{sub 3} radicals may play an important role in the photochemistry of nitrogen ices in astronomical environments.

  11. Microstructure and tensile properties of oxide dispersion strengthened Fe–14Cr–0.3Y{sub 2}O{sub 3} and Fe–14Cr–2W–0.3Ti–0.3Y{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Auger, M.A., E-mail: mauger@fis.uc3m.es [Departamento de Física, Universidad Carlos III de Madrid, 28911 Leganés (Spain); Castro, V. de; Leguey, T.; Monge, M.A.; Muñoz, A.; Pareja, R. [Departamento de Física, Universidad Carlos III de Madrid, 28911 Leganés (Spain)

    2013-11-15

    Two ODS ferritic steels with nominal compositions (wt.%): Fe–14Cr–0.3Y{sub 2}O{sub 3} and Fe–14Cr–2W–0.3Ti–0.3Y{sub 2}O{sub 3} have been produced by mechanical alloying and consolidation by hot isostatic pressing. The microstructure and tensile properties of these materials after being forged and heat-treated at 1123 K have been investigated to clarify the interrelation between composition, microstructure and mechanical properties. The second-phase precipitates in these alloys have been analyzed by high-angle annular dark-field imaging in scanning TEM mode and electron diffraction. Fe–14Cr–2W–0.3Ti–0.3Y{sub 2}O{sub 3} exhibits a duplex microstructure consisting of large recrystallized grains, as large as 1.5 μm, and unrecovered regions containing submicron equiaxed grains. In addition, three types of secondary phase particles have been found: large M{sub 23}C{sub 6} particles containing W and Cr, (Cr + Ti) rich spherical particles with diameters between 50 and 500 nm, and fine (Y + Ti) oxide particles with sizes below 30 nm. In contrast, Fe14CrY shows a uniform structure of equiaxed grains, with sizes in the range 0.5–3 μm, containing a fine dispersion of Y oxide particles (<30 nm) homogeneously distributed inside the grains, as well as large carbide and oxide particles. Tensile tests performed over the temperature range 273–973 K have revealed that the alloy containing W and Ti has lower yield and tensile strengths than Fe–14Cr–0.3Y{sub 2}O{sub 3} at temperatures up to 773 K, but the opposite appears to occur beyond this temperature.

  12. Deuterium permeation properties of Er{sub 2}O{sub 3}/Cr{sub 2}O{sub 3} composite coating prepared by MOCVD on 316L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yunyi, E-mail: wuyunyi@grinm.com [Department of Energy Materials and Technology, General Research Institute for Nonferrous Metals, Beijing (China); Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong (China); Wang, Shumao; Li, Shuai; He, Di; Liu, Xiaopeng; Jiang, Lijun [Department of Energy Materials and Technology, General Research Institute for Nonferrous Metals, Beijing (China); Huang, Haitao [Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong (China)

    2016-12-15

    Highlights: • Grain sizes of the coatings enlarged with increasing thickness of Cr{sub 2}O{sub 3} layer. • Er{sub 2}O{sub 3}/Cr{sub 2}O{sub 3} (80 nm) composite coating showed the maximum reduction in deuterium permeability. • The Er{sub 2}O{sub 3}/Cr{sub 2}O{sub 3} (80 nm) composite coating showed larger adhesion force value 9.2 N than the Er{sub 2}O{sub 3} coating. • Impurity layer formed at the interface of the Er{sub 2}O{sub 3} coating due to element diffusion. - Abstract: In this work, an Er{sub 2}O{sub 3}/Cr{sub 2}O{sub 3} composite coatings on 316L stainless steel were prepared by metalorganic chemical vapor deposition (MOCVD). Effect of Cr{sub 2}O{sub 3} layer on the microstructure, mechanical properties and deuterium permeation properties of Er{sub 2}O{sub 3} coating was investigated. It was found grain sizes of the coatings enlarged with increasing the thickness of Cr{sub 2}O{sub 3} layer. The Er{sub 2}O{sub 3}/Cr{sub 2}O{sub 3} (80 nm) composite coating showed larger adhesion force value 9.2 N than the Er{sub 2}O{sub 3} coating. The Cr{sub 2}O{sub 3} layer adding could significantly enhance the deuterium permeation inhibition property of the coatings. The single-layer Er{sub 2}O{sub 3} coating exhibited the minimum reduction in deuterium permeability, and the permeation reduction factor (PRF) values were in the range of 95–146 at 823–973 K. The maximum reduction in deuterium permeability was obtained from the Er{sub 2}O{sub 3}/Cr{sub 2}O{sub 3} (80 nm) composite coating, and the PRF values were in the range of 463–206 at 823–973 K. With further increasing thickness of the Cr{sub 2}O{sub 3} layer to 120 nm, the hydrogen permeation inhibition performance of the composite coating lower instead. Furthermore, apparent delamination of coating was illustrated on the single-layer Er{sub 2}O{sub 3} coating after the permeation measurement, and this might be the main reason for the transformation to diffusion limiting process.

  13. Meteorological and trace gas factors affecting the number concentration of atmospheric Aitken (Dp = 50 nm particles in the continental boundary layer: parameterization using a multivariate mixed effects model

    Directory of Open Access Journals (Sweden)

    M. C. Facchini

    2011-01-01

    Full Text Available Measurements of aerosol size distribution and different gas and meteorological parameters, made in three polluted sites in Central and Southern Europe: Po Valley, Italy, Melpitz and Hohenpeissenberg in Germany, were analysed for this study to examine which of the meteorological and trace gas variables affect the number concentration of Aitken (Dp= 50 nm particles. The aim of our study was to predict the number concentration of 50 nm particles by a combination of in-situ meteorological and gas phase parameters. The statistical model needs to describe, amongst others, the factors affecting the growth of newly formed aerosol particles (below 10 nm to 50 nm size, but also sources of direct particle emissions in that size range. As the analysis method we used multivariate nonlinear mixed effects model. Hourly averages of gas and meteorological parameters measured at the stations were used as predictor variables; the best predictive model was attained with a combination of relative humidity, new particle formation event probability, temperature, condensation sink and concentrations of SO2, NO2 and ozone. The seasonal variation was also taken into account in the mixed model structure. Model simulations with the Global Model of Aerosol Processes (GLOMAP indicate that the parameterization can be used as a part of a larger atmospheric model to predict the concentration of climatically active particles. As an additional benefit, the introduced model framework is, in theory, applicable for any kind of measured aerosol parameter.

  14. Bimolecular reaction of CH{sub 3} + CO in solid p-H{sub 2}: Infrared absorption of acetyl radical (CH{sub 3}CO) and CH{sub 3}-CO complex

    Energy Technology Data Exchange (ETDEWEB)

    Das, Prasanta [Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Lee, Yuan-Pern, E-mail: yplee@mail.nctu.edu.tw [Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan (China)

    2014-06-28

    We have recorded infrared spectra of acetyl radical (CH{sub 3}CO) and CH{sub 3}-CO complex in solid para-hydrogen (p-H{sub 2}). Upon irradiation at 248 nm of CH{sub 3}C(O)Cl/p-H{sub 2} matrices, CH{sub 3}CO was identified as the major product; characteristic intense IR absorption features at 2990.3 (ν{sub 9}), 2989.1 (ν{sub 1}), 2915.6 (ν{sub 2}), 1880.5 (ν{sub 3}), 1419.9 (ν{sub 10}), 1323.2 (ν{sub 5}), 836.6 (ν{sub 7}), and 468.1 (ν{sub 8}) cm{sup −1} were observed. When CD{sub 3}C(O)Cl was used, lines of CD{sub 3}CO at 2246.2 (ν{sub 9}), 2244.0 (ν{sub 1}), 1866.1 (ν{sub 3}), 1046.7 (ν{sub 5}), 1029.7 (ν{sub 4}), 1027.5 (ν{sub 10}), 889.1 (ν{sub 6}), and 723.8 (ν{sub 7}) cm{sup −1} appeared. Previous studies characterized only three vibrational modes of CH{sub 3}CO and one mode of CD{sub 3}CO in solid Ar. In contrast, upon photolysis of a CH{sub 3}I/CO/p-H{sub 2} matrix with light at 248 nm and subsequent annealing at 5.1 K before re-cooling to 3.2 K, the CH{sub 3}-CO complex was observed with characteristic IR features at 3165.7, 3164.5, 2150.1, 1397.6, 1396.4, and 613.0 cm{sup −1}. The assignments are based on photolytic behavior, observed deuterium isotopic shifts, and a comparison of observed vibrational wavenumbers and relative IR intensities with those predicted with quantum-chemical calculations. This work clearly indicates that CH{sub 3}CO can be readily produced from photolysis of CH{sub 3}C(O)Cl because of the diminished cage effect in solid p-H{sub 2} but not from the reaction of CH{sub 3} + CO because of the reaction barrier. Even though CH{sub 3} has nascent kinetic energy greater than 87 kJ mol{sup −1} and internal energy ∼42 kJ mol{sup −1} upon photodissociation of CH{sub 3}I at 248 nm, its energy was rapidly quenched so that it was unable to overcome the barrier height of ∼27 kJ mol{sup −1} for the formation of CH{sub 3}CO from the CH{sub 3} + CO reaction; a barrierless channel for formation of a CH{sub 3}-CO

  15. Impact of silica environment on hyperfine interactions in ε-Fe{sub 2}O{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kubíčková, Lenka, E-mail: sagittaria.64@gmail.com; Kohout, Jaroslav [Charles University in Prague, Faculty of Mathematics and Physics (Czech Republic); Brázda, Petr; Veverka, Miroslav [Institute of Physics of the AS CR, v.v.i. (Czech Republic); Kmječ, Tomáš; Kubániová, Denisa [Charles University in Prague, Faculty of Mathematics and Physics (Czech Republic); Bezdička, Petr [Institute of Inorganic Chemistry of the AS CR, v.v.i. (Czech Republic); Klementová, Mariana; Šantavá, Eva [Institute of Physics of the AS CR, v.v.i. (Czech Republic); Závěta, Karel [Charles University in Prague, Faculty of Mathematics and Physics (Czech Republic)

    2016-12-15

    Magnetic nanoparticles have found broad applications in medicine, especially for cell targeting and transport, and as contrast agents in MRI. Our samples of ε-Fe{sub 2}O{sub 3} nanoparticles were prepared by annealing in silica matrix, which was leached off and the bare particles were then coated with amorphous silica layers of various thicknesses. The distribution of particle sizes was determined from the TEM pictures giving the average size ∼20 nm and the thickness of silica coating ∼5; 8; 12; 19 nm. The particles were further characterized by the XRPD and DC magnetic measurements. The nanoparticles consisted mainly of ε-Fe{sub 2}O{sub 3} with admixtures of ∼1 % of the α phase and less than 1 % of the γ phase. The hysteresis loops displayed coercivities of ∼2 T at room temperature. The parameters of hyperfine interactions were derived from transmission Mössbauer spectra. Observed differences of hyperfine fields for nanoparticles in the matrix and the bare ones are ascribed to strains produced during cooling of the composite. This interpretation is supported by slight changes of their lattice parameters and increase of the elementary cell volume deduced from XRD. The temperature dependence of the magnetization indicated a two-step magnetic transition of the ε-Fe{sub 2}O{sub 3} nanoparticles spread between ∼85 K and ∼150 K, which is slightly modified by remanent tensile stresses in the case of nanoparticles in the matrix. The subsequent coating of the bare particles by silica produced no further change in hyperfine parameters, which indicates that this procedure does not modify magnetic properties of nanoparticles.

  16. Influence of physical properties and chemical composition of sample on formation of aerosol particles generated by nanosecond laser ablation at 213 nm

    Energy Technology Data Exchange (ETDEWEB)

    Hola, Marketa, E-mail: mhola@sci.muni.c [Department of Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic); Konecna, Veronika [Department of Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic); Mikuska, Pavel [Institute of Analytical Chemistry, Academy of Sciences of the Czech Republic v.v.i., Veveri 97, 602 00 Brno (Czech Republic); Kaiser, Jozef [Institute of Physical Engineering, Faculty of Mechanical Engineering, Brno University of Technology, Technicka 2896/2, 616 69 Brno (Czech Republic); Kanicky, Viktor [Department of Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic)

    2010-01-15

    The influence of sample properties and composition on the size and concentration of aerosol particles generated by nanosecond Nd:YAG laser ablation at 213 nm was investigated for three sets of different materials, each containing five specimens with a similar matrix (Co-cemented carbides with a variable content of W and Co, steel samples with minor differences in elemental content and silica glasses with various colors). The concentration of ablated particles (particle number concentration, PNC) was measured in two size ranges (10-250 nm and 0.25-17 mum) using an optical aerosol spectrometer. The shapes and volumes of the ablation craters were obtained by Scanning Electron Microscopy (SEM) and by an optical profilometer, respectively. Additionally, the structure of the laser-generated particles was studied after their collection on a filter using SEM. The results of particle concentration measurements showed a significant dominance of particles smaller than 250 nm in comparison with larger particles, irrespective of the kind of material. Even if the number of particles larger than 0.25 mum is negligible (up to 0.1%), the volume of large particles that left the ablation cell can reach 50% of the whole particle volume depending on the material. Study of the ablation craters and the laser-generated particles showed a various number of particles produced by different ablation mechanisms (particle splashing or condensation), but the similar character of released particles for all materials was observed by SEM after particle collection on the membrane filter. The created aerosol always consisted of two main structures - spherical particles with diameters from tenths to units of micrometers originally ejected from the molten surface layer and mum-sized 'fibres' composed of primary agglomerates with diameters in the range between tens and hundreds of nanometers. The shape and structure of ablation craters were in good agreement with particle concentration

  17. Uniform, luminescent Eu:LuF{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Becerro, Ana I., E-mail: anieto@icmse.csic.es; Gonzalez-Mancebo, Daniel; Ocaña, Manuel [Instituto de Ciencia de Materiales de Sevilla (CSIC-University of Seville) (Spain)

    2015-01-15

    A simple procedure for the synthesis of orthorhombic, uniform, LuF{sub 3} particles with two different morphologies (rhombus- and cocoon-like) and nanometer and sub-micrometer size, respectively, is reported. The method consists in the aging, at 120 °C for 2 h, a solution containing [BMIM]BF{sub 4} ionic liquid (0.5 mL) and lutetium acetate (in the case of the rhombi) or lutetium nitrate (in the case of the cocoons) (0.02 M) in ethylene glycol (total volume 10 mL). This synthesis method was also adequate for the synthesis of Eu{sup 3+}-doped LuF{sub 3} particles of both morphologies, whose luminescence properties were investigated in detail. The experimental observations reported herein suggest that these materials are suitable phosphors for optoelectronic as well as in vitro biotechnological applications.

  18. Observation of lower defect density in CH{sub 3}NH{sub 3}Pb(I,Cl){sub 3} solar cells by admittance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Minlin; Lan, Fei; Tao, Quan; Li, Guangyong, E-mail: gaod@pitt.edu, E-mail: gul6@pitt.edu [Department of Electrical and Computer Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Zhao, Bingxin [Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Key Laboratory of Advanced Functional Materials, College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124 (China); Wu, Jiamin; Gao, Di, E-mail: gaod@pitt.edu, E-mail: gul6@pitt.edu [Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States)

    2016-06-13

    The introduction of Cl into CH{sub 3}NH{sub 3}PbI{sub 3} precursors is reported to enhance the performance of CH{sub 3}NH{sub 3}PbI{sub 3} solar cell, which is attributed to the significantly increased diffusion lengths of carriers in CH{sub 3}NH{sub 3}Pb(I,Cl){sub 3} solar cell. It has been assumed but never experimentally approved that the defect density in CH{sub 3}NH{sub 3}Pb(I,Cl){sub 3} solar cell should be reduced according to the higher carrier lifetime observed from photoluminescence (PL) measurement. We have fabricated CH{sub 3}NH{sub 3}Pb(I,Cl){sub 3} solar cell by adding a small amount of Cl source into CH{sub 3}NH{sub 3}PbI{sub 3} precursor. The performance of CH{sub 3}NH{sub 3}Pb(I,Cl){sub 3} solar cell is significantly improved from 15.39% to 18.60%. Results from scanning electron microscopy and X-ray diffraction indicate that the morphologies and crystal structures of CH{sub 3}NH{sub 3}PbI{sub 3} and CH{sub 3}NH{sub 3}Pb(I,Cl){sub 3} thin films remain unchanged. Open circuit voltage decay and admittance spectroscopy characterization jointly approve that Cl plays an extremely important role in suppressing the formation of defects in perovskite solar cells.

  19. Investigation of Al{sub 2}O{sub 3} barrier film properties made by atomic layer deposition onto fluorescent tris-(8-hydroxyquinoline) aluminium molecular films

    Energy Technology Data Exchange (ETDEWEB)

    Maindron, Tony; Aventurier, Bernard [LETI/DOPT/SCOOP/Laboratoire des Composants pour la Visualisation, CEA-LETI, MINATEC Campus, 17 rue des Martyrs, F-38054 Grenoble Cedex 9 (France); Ghazouani, Ahlem; Jullien, Tony [LETI/DTSI/SDEP/Laboratoire Dépôt Equipe 2, CEA-LETI, MINATEC Campus, 17 rue des Martyrs, F-38054 Grenoble Cedex 9 (France); Rochat, Névine [LETI/DTSI/Service de Caractérisation des Matériaux et Composants, CEA-LETI, MINATEC Campus, 17 rue des Martyrs, F-38054 Grenoble Cedex 9 (France); Simon, Jean-Yves; Viasnoff, Emilie [LETI/DOPT/SCOOP/Laboratoire des Composants pour la Visualisation, CEA-LETI, MINATEC Campus, 17 rue des Martyrs, F-38054 Grenoble Cedex 9 (France)

    2013-12-02

    Al{sub 2}O{sub 3} films have been deposited at 85 °C by atomic layer deposition onto single 100 nm thick tris-(8-hydroxyquinoline) aluminium (AlQ{sub 3}) films made onto silicon wafers. It has been found that a thick ALD-deposited Al{sub 2}O{sub 3} layer (> 11 nm) greatly prevents the photo-oxidation of AlQ{sub 3} films when exposed to continuous UV irradiation (350 mW/cm{sup 2}). Thin Al{sub 2}O{sub 3} thicknesses (< 11 nm) on the contrary yield lower barrier performances. Defects in the Al{sub 2}O{sub 3} layer have been easily observed as non-fluorescent AlQ{sub 3} singularities, or black spots, under UV light on the system Si/AlQ{sub 3}/Al{sub 2}O{sub 3} stored into laboratory conditions (22 °C/50% Relative Humidity (RH)) for long time scale (∼ 2000 h). Accelerated aging conditions in a climatic chamber (85 °C/85% RH) also allow faster visualization of the same defects (168 h). The black spot density grows upon time and the black spot density occurrence rates have been calculated to be 0.024 h{sup −1}·cm{sup −2} and 0.243 h{sup −1}·cm{sup −2} respectively for the two testing conditions. A detailed investigation of these defects did show that they cannot be ascribed to the presence of a detectable particle. In that sense they are presumably the consequence of the existence of nanometre-scaled defects which cannot be detected onto fresh samples. Interestingly, an additional overcoating of ebeam-deposited SiO{sub 2} onto the Si/AlQ{sub 3}/Al{sub 2}O{sub 3} sample helps to decrease drastically the black spot density occurrence rates down to 0.004 h{sup −1}·cm{sup −2} and 0.04 h{sup −1}·cm{sup −2} respectively for 22 °C/50% RH and 85 °C/85% RH testing conditions. These observations highlight the moisture sensitivity of low temperature ALD-deposited Al{sub 2}O{sub 3} films and confirm the general idea that a single Al{sub 2}O{sub 3} ALD film performs as an ultra-high barrier but needs to be overprotected from water condensation by an

  20. Ni{sub 3}Al aluminide alloys

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.T.

    1993-10-01

    This paper provides a brief review of the recent progress in research and development of Ni{sub 3}Al and its alloys. Emphasis has been placed on understanding low ductility and brittle fracture of Ni{sub 3}Al alloys at ambient and elevated temperatures. Recent studies have resulted in identifying both intrinsic and extrinsic factors governing the fracture behavior of Ni{sub 3}Al alloys. Parallel efforts on alloy design using physical metallurgy principles have led to properties for structural use. Industrial interest in these alloys is high, and examples of industrial involvement in processing and utilization of these alloys are briefly mentioned.

  1. Synthesis of Ternary Nitrides From Intermetallic Precursors: Modes of Nitridation in Model Cr<sub>3Pt Alloys to Form Cr<sub>3PtN Perovskite and Applications to Other Systems

    Energy Technology Data Exchange (ETDEWEB)

    Brady, Michael P [ORNL; Wrobel, Sarah [University of Tennessee, Knoxville (UTK); Lograsso, Tom [Ames Laboratory; Payzant, E Andrew [ORNL; Hoelzer, David T [ORNL; Horton Jr, Joe A [ORNL; Walker, Larry R [ORNL

    2004-01-01

    The use of intermetallic alloy precursors is explored as a new means to synthesize complex transition and refractory metal nitrides, carbides, and related phases. The conditions under which model single-phase Cr{sub 3}Pt and two-phase Cr{sub 3}Pt-dispersed Cr alloys form Cr{sub 3}PtN antiperovskite when thermally nitrided were studied. Phenomenological experiments suggest that the key variable to achieving single-phase Cr{sub 3}PtN surface layers is the Cr{sub 3}Pt phase composition. In two-phase {beta}-Cr-Cr{sub 3}Pt alloys, the formation of single-phase Cr{sub 3}PtN at Cr{sub 3}Pt precipitates by in-place internal nitridation was found to be a strong function of the size of the Cr{sub 3}Pt dispersion in the microstructure. Nanoscale Cr{sub 3}Pt dispersions were readily converted to near single-phase Cr{sub 3}PtN, whereas nitridation of coarse Cr{sub 3}Pt particles resulted in a cellular or discontinuous-type reaction to form a lath mixture of Cr{sub 3}PtN and a more Cr-rich Cr{sub 3}Pt or {beta}-Cr. The potential for using such external/internal oxidation phenomena as a synthesis approach to layered or composite surfaces of ternary ceramic phases (nitrides, carbides, borides, etc.) of technological interest such as the Ti{sub 3}AlC{sub 2} phase, bimetallic nitride, and carbide catalysts (Co{sub 3}Mo{sub 3}N and Co{sub 3}Mo{sub 3}C and related phases), and magnetic rare earth nitrides (Fe{sub 17}Sm{sub 2}N{sub x} or Fe{sub 17}Nd{sub 2}N{sub x}) is discussed.

  2. Syntheses and crystal structures of BaAgTbS{sub 3}, BaCuGdTe{sub 3}, BaCuTbTe{sub 3}, BaAgTbTe{sub 3}, and CsAgUTe{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Prakash, Jai; Beard, Jessica C.; Ibers, James A. [Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113 (United States); Mesbah, Adel [Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113 (United States); ICSM-UMR 5257 CNRS/CEA/UM2/ENSCM, Bat 426, BP 17171, 30207 Bagnols/Ceze (France)

    2015-06-15

    Five new quaternary chalcogenides of the 1113 family, namely BaAgTbS{sub 3}, BaCuGdTe{sub 3}, BaCuTbTe{sub 3}, BaAgTbTe{sub 3}, and CsAgUTe{sub 3}, were synthesized by the reactions of the elements at 1173-1273 K. For CsAgUTe{sub 3} CsCl flux was used. Their crystal structures were determined by single-crystal X-ray diffraction studies. The sulfide BaAgTbS{sub 3} crystallizes in the BaAgErS{sub 3} structure type in the monoclinic space group C{sup 3},{sub 2h}-C2/m, whereas the tellurides BaCuGdTe{sub 3}, BaCuTbTe{sub 3}, BaAgTbTe{sub 3}, and CsAgUTe{sub 3} crystallize in the KCuZrS{sub 3} structure type in the orthorhombic space group D{sup 1},{sub 2}{sup 7},{sub h}-Cmcm. The BaAgTbS{sub 3} structure consists of edge-sharing [TbS{sub 6}{sup 9-}] octahedra and [AgS{sub 5}{sup 9-}] trigonal pyramids. The connectivity of these polyhedra creates channels that are occupied by Ba atoms. The telluride structure features {sup 2}{sub ∞}[MLnTe{sub 3}{sup 2-}] layers for BaCuGdTe{sub 3}, BaCuTbTe{sub 3}, BaAgTbTe{sub 3}, and {sup 2}{sub ∞}[AgUTe{sub 3}{sup 1-}] layers for CsAgUTe{sub 3}. These layers comprise [MTe{sub 4}] tetrahedra and [LnTe{sub 6}] or [UTe{sub 6}] octahedra. Ba or Cs atoms separate these layers. As there are no short Q..Q (Q = S or Te) interactions these compounds achieve charge balance as Ba{sup 2+}M{sup +}Ln{sup 3+}(Q{sup 2-}){sub 3} (Q = S and Te) and Cs{sup +}Ag{sup +}U{sup 4+}(Te{sup 2-}){sub 3}. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Hierarchically structured carbon-coated SnO{sub 2}-Fe{sub 3}O{sub 4} microparticles with enhanced lithium storage performance

    Energy Technology Data Exchange (ETDEWEB)

    Chai, Xiaohan; Shi, Chunsheng [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin, 300072 (China); Liu, Enzuo [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin, 300072 (China); Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072 (China); Li, Jiajun [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin, 300072 (China); Zhao, Naiqin [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin, 300072 (China); Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072 (China); Key Laboratory of Advanced Ceramics and Machining Technology, Ministry of Education, Tianjin University, Tianjin, 300072 (China); He, Chunnian, E-mail: cnhe08@tju.edu.cn [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin, 300072 (China); Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072 (China); Key Laboratory of Advanced Ceramics and Machining Technology, Ministry of Education, Tianjin University, Tianjin, 300072 (China)

    2016-01-15

    Graphical abstract: Hierarchically structured SnO{sub 2}-Fe{sub 3}O{sub 4}@C microparticles for lithium-ion battery anode are developed by a facile and scalable strategy. - Highlights: • Hierarchically structured SnO{sub 2}-Fe{sub 3}O{sub 4}@C micrometer-sized particles were synthesized. • The SnO{sub 2}-Fe{sub 3}O{sub 4}@C micrometer-sized particles deliver high reversible lithium storage capacity. • The wrapped carbon layer can buffer the volume expansion of SnO{sub 2}-Fe{sub 3}O{sub 4}. - Abstract: A facile and scalable strategy was developed to fabricate SnO{sub 2}-Fe{sub 3}O{sub 4}@C micrometer-sized particles as a good lithium-ion battery anode. The obtained materials were constructed by aggregated nanoclusters (100–200 nm) consisting of SnO{sub 2}-Fe{sub 3}O{sub 4}@C nanospheres (20 ∼ 30 nm), in which SnO{sub 2} and Fe{sub 3}O{sub 4} nanoparticles (5 ∼ 8 nm) were homogeneously embedded in a percolating carbonaceous network with an average thickness of about 3 nm. SnO{sub 2}-Fe{sub 3}O{sub 4}@C microparticles were synthesized by a one-pot hydrothermal process followed by annealing under Ar and subsequent chemical vapor transformation (CVT) under vacuum. The peculiar strategy allows to obtain hierarchical structure of micrometer-sized particles including nanospheres, nanoclusters and micro-scale particles, and the combination of SnO{sub 2} and Fe{sub 3}O{sub 4} could promote the synergistic effects to enhance the reversible capacity as well as the structural stability. Meanwhile, the carbon layer, homogeneously covering the nanoparticles does not only accommodate the volume change of active materials to maintain the structural integrity but also forms a conductive network throughout the whole micro-sized structure during charge/discharge processes. As a result, the electrode of SnO{sub 2}-Fe{sub 3}O{sub 4}@C microparticles exhibits good rate performance (1056 mAh g{sup −1} at 0.1 C, 734 mAh g{sup −1} at 0.2 C, 449 mAh g{sup −1} at 0.5 C, 212

  4. Strain control of Urbach energy in Cr-doped PrFeO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Anil; Warshi, M.K.; Mishra, Vikash; Saxena, Shailendra K.; Kumar, Rajesh; Sagdeo, Pankaj R. [Indian Institute of Technology Indore, Material Research Laboratory, Discipline of Physics and MEMS, Indore (India)

    2017-09-15

    Polycrystalline samples of PrFe{sub 1-x}Cr{sub x}O{sub 3} having average particle size of ∝90 nm have been prepared by wet chemical route. The structural phase purity of the prepared samples is confirmed by powder X-ray diffraction followed by Rietveld refinements. It is observed that with Cr doping, the Urbach energy (E{sub u}) increases. The E{sub u} is measure of the various disorders present in the sample, such as chemical and structural. To understand the contribution to the E{sub u} due to chemical and structural disorders, we have probed the chemical and structural disorders in the samples by elemental mappings and through X-ray diffraction experiments, respectively. Elemental mapping confirms chemical homogeneity of prepared samples. It is observed that with Cr doping the crystallographic strain increases and Urbach energy shows the similar scaling. (orig.)

  5. Size-dependent properties of YBa sub 2 Cu sub 3 O sub 6 sub + sub x nanopowder

    CERN Document Server

    Paturi, P; Huhtinen, H; Huhtala, V P; Laiho, R

    2003-01-01

    YBa sub 2 Cu sub 3 O sub 6 sub + sub x nanopowder, prepared by the citrate sol-gel method, is segregated by sedimentation in ethanol into three size groups with average particle heights of 0.7, 1.6 and 2.3 nm. The structural properties and composition of the powders, investigated by x-ray diffraction, atomic force microscopy, Auger electron spectroscopy and EPR-spectroscopy, show no clear differences, except the size. According to investigations by magnetometry and by non-resonant microwave absorption the as-prepared powder contains weak links which, however, disappear during the segregation. The magnetic susceptibility of the samples decreases with the decreasing particle size, in agreement with the susceptibility values calculated from the London equations for cylindrical particles smaller than the London penetration depth. In all three size groups the critical temperature of superconductivity is 92 K.

  6. Preparation of RGO/Fe{sub 3}O{sub 4}/poly (acrylic acid) hydrogel nanocomposites with improved magnetic, thermal and electrochemical properties

    Energy Technology Data Exchange (ETDEWEB)

    Didehban, K.H., E-mail: Didehban95@gmail.com; Mohammadi, L.; Azimvand, J.

    2017-07-01

    A hydrogel nanocomposite composed of reduced graphene oxide (RGO), iron oxide (Fe{sub 3}O{sub 4}) nanoparticles, and polyacrylic acid (PAA) was prepared using radical polymerization. Different percentages of RGO, Fe{sub 3}O{sub 4}, and PAA were used to prepare the nanocomposite. Fourier transform infrared spectroscopy (FTIR) results confirmed the formation of the nanocomposite’s chemical structure. X-ray power diffraction (XRD) patterns revealed the principal peak’s 2θ value to be 77.39° with the size of the nanocomposite particles estimated at 96 nm. Results indicated that the electrochemical capacity of the nanocomposites was controlled by the weight percentage of RGO. Increases to the potential scan rate reduced porosity and surface area, thereby decreasing the electrochemical capacity of the nanocomposites. Moreover, increasing the percentage of Fe{sub 3}O{sub 4} nanoparticles in the nanocomposites improved their magnetic characteristics and thermal properties. The latter also improved when the RGO percentage increased. - Highlights: • A hydrogel nanocomposite composed of RGO/Fe{sub 3}O{sub 4}/PAA was synthesized successfully. • Increasing the percentage of iron nanoparticles improved magnetic properties. • Increasing the percentage of RGO improved thermal and electrochemical capacity. • The Fe{sub 3}O{sub 4} nanoparticles directly affected magnetic properties.

  7. Comparison of thermal compatibility between atomized and comminuted U{sub 3}Si dispersion fuels

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Woo-Seog; Park, Jong-Man; Kim, Chang-Kyu; Kuk, II-Hyun [Korea Atomic Research Institute, Taejon (Korea, Republic of)

    1997-08-01

    Thermal compatibility of atomized U{sub 3}Si dispersion fuels were evaluated up to 2600 hours in the temperature range from 250 to 500{degrees}C, and compared with that of comminuted U{sub 3}Si. Atomized U{sub 3}Si showed better performance in terms of volume expansion of fuel meats. The reaction zone of U{sub 3}Si and Al occurred along the grain boundaries and deformation bands in U{sub 3}Si particles. Pores around fuel particles appeared at high temperature or after long-term annealing tests to remain diffusion paths over the trench of the pores. The constraint effects of cladding on fuel rod suppressed the fuel meat, and reduced the volume expansion.

  8. Functionalized multimodal ZnO@Gd{sub 2}O{sub 3} nanosystems to use as perspective contrast agent for MRI

    Energy Technology Data Exchange (ETDEWEB)

    Babayevska, Nataliya, E-mail: natbab@amu.edu.pl; Florczak, Patryk; Woźniak-Budych, Marta; Jarek, Marcin; Nowaczyk, Grzegorz; Zalewski, Tomasz; Jurga, Stefan

    2017-05-15

    Highlights: • The multimodal ZnO@Gd{sub 2}O{sub 3} nanostructures were obtained by wet chemistry methods. • FA and Dox have been effectively bonded onto the ZnO nanoparticles surface. • Functionalized ZnO@Gd{sub 2}O{sub 3} NPs are good contrast agents, useful for MR imaging. - Abstract: The main aim of this research was the synthesis of the multimodal hybrid ZnO@Gd{sub 2}O{sub 3} nanostructures as prospective contrast agent for Magnetic Resonance Imaging (MRI) for bio-medical applications. The nanoparticles surface was functionalized by organosilicon compounds (OSC) then, by folic acid (FA) as targeting agent and doxorubicin (Dox) as chemotherapeutic agent. Doxorubicin and folic acid were attached to the nanoparticles surface by amino groups as well as due to attractive physical interactions. The morphology and crystallography of the nanostructures were studied by HRTEM and SAXS techniques. After ZnO nanoparticles surface modification by Gd{sup 3+} and annealing at 900 °C, ZnO@Gd{sub 2}O{sub 3} nanostructures are polydispersed with size 30–100 nm. NMR (Nuclear Magnetic Resonance) studies of ZnO@Gd{sub 2}O{sub 3} were performed on fractionated particles with size up to 50 nm. Fourier transform infrared spectroscopy (FTIR), UV–vis spectroscopy, zeta-potential measurements and energy dispersive X-ray analysis (EDX) showed that functional groups have been effectively bonded onto the nanoparticles surface. The high adsorption capacity of folic acid (up to 20%) and doxorubicin (up to 40%) on nanoparticles was reached upon 15 min of adsorption process in a temperature-dependent manner. The nuclear magnetic resonance (NMR) relaxation measurements confirmed that the obtained ZnO@Gd{sub 2}O{sub 3} nanostructures could be good contrast agents, useful for magnetic resonance imaging.

  9. Linear birefringence and dichroism measurement in oil-based Fe{sub 3}O{sub 4} magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Jing-Fung, E-mail: jacklin@cc.feu.edu.tw [Graduate School of Computer Application Engineering, Far East University, Tainan 74448, Taiwan (China); Wang, Chia-Hung [Department of Automation and Control Engineering, Far East University, Tainan 74448, Taiwan (China); Lee, Meng-Zhe [Graduate School of Computer Application Engineering, Far East University, Tainan 74448, Taiwan (China)

    2013-04-15

    To prepare dispersed Fe{sub 3}O{sub 4} magnetic nanoparticles (MNPs), we adopt a co-precipitation method and consider surfactant amount, stirring speed, dispersion mode, and molar ratio of Fe{sup 3+}/Fe{sup 2+}. Via transmission electronic microscopy and X-ray diffractometry, we characterize the dispersibility and size of the products and determine the appropriate values of experimental parameters. The stirring speed is 1000 rpm in titration. There is simultaneous ultrasonic vibration and mechanical stirring in the titration and surface coating processes. The surfactant amount of oleic acid is 1.2 ml for molar ratios of Fe{sup 3+}/Fe{sup 2+} as 1.7:1, 1.8:1, and 1.9:1. The average diameters of these Fe{sub 3}O{sub 4} MNPs are 11 nm, and the ratios of saturation magnetization for these MNPs to that of bulk magnetite range from 45% to 65%, with remanent magnetization close to zero and low coercivity. Above all, the linear birefringence and dichroism measurements of the kerosene-based ferrofluid (FF) samples are investigated by a Stokes polarimeter. The influences of particle size distribution and magnetization in the birefringence and dichroism measurements of FFs are discussed. - Highlights: ► Dispersed Fe{sub 3}O{sub 4} magnetic nanoparticles (MNPs) are produced by a co-precipitation method. ► Simultaneous ultrasonic vibration and mechanical stirring are used in titration and coating. ► Diameters of Fe{sub 3}O{sub 4} MNPs are determined as 11 nm with maximum magnetization as 54.27 emu/g. ► Birefringence and dichroism of ferrofluids are obtained by a Stokes polarimeter successfully.

  10. Thermoluminescent response of LaAlO{sub 3}:Pr; Respuesta termoluminiscente de LaAlO{sub 3}:Pr

    Energy Technology Data Exchange (ETDEWEB)

    Morales H, A.; Zarate M, J. [Universidad Michoacana de San Nicolas de Hidalgo, Instituto de Investigacion en Metalurgia y Materiales, Ciudad Universitaria, Edif. U, 58060 Morelia, Michoacan (Mexico); Azorin N, J. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (Mexico); Rivera M, T., E-mail: feyo_yo@hotmail.com [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, 11500 Mexico D. F. (Mexico)

    2015-10-15

    In this study, the thermoluminescence response of doped lanthanum aluminate (LaAlO{sub 3}) with praseodymium ion (Pr) obtained by the Pechini method and drying by the spraying technique Spry Dryer was studied. The obtained powders were analyzed structurally by the X-ray diffraction technique; the morphological characterization was by the scanning electron microscopy technique. The obtained powders at 800 degrees C presented crystallinity and showed a Rhombohedral crystal structure, this phase was observed by X-ray diffraction patterns. Thermoluminescence response of LaAlO{sub 3}:Pr showed a brightness curve with a peak centered at 157 degrees C. The sensitivity of the doped samples was improved about 90 times in comparison with the undoped sample. Thermoluminescence response in function of the wavelength showed a maximum at 230 nm, reproducibility of thermoluminescence response was ±50%. Also the fading in thermoluminescence response was studied. (Author)

  11. Study of nanostructural behavior and transport properties of BaTiO{sub 3} doped vanadate glasses and glass-ceramics dispersed with ferroelectric nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Al-Assiri, M.S., E-mail: msassiri@kku.edu.s [Department of Physics, Faculty of Science, King Khaled University, P.O. Box 9004, Abha (Saudi Arabia); El-Desoky, M.M., E-mail: mmdesoky@gmail.co [Department of Physics, Faculty of Science, King Khaled University, P.O. Box 9004, Abha (Saudi Arabia); Department of Physics, Faculty of Education, Suez Canal University, Al-Arish (Egypt); Al-Hajry, A.; Al-Shahrani, A.; Al-Mogeeth, A.M. [Department of Physics, Faculty of Science, King Khaled University, P.O. Box 9004, Abha (Saudi Arabia); Bahgat, A.A., E-mail: alaabahgat@yahoo.co [Department of Physics, Faculty of Science, King Khaled University, P.O. Box 9004, Abha (Saudi Arabia); Department of Physics, Faculty of Science, Al-Azhar University, Nasr City 11884, Cairo (Egypt)

    2009-05-01

    Nanostructural behavior and electrical properties of BaTiO{sub 3}-(100-x)V{sub 2}O{sub 5} glasses (where x=35, 40, 45 and 50 mol%) and their corresponding nanocrystalline glass-ceramics were studied. Scanning electron microscopy (SEM) of quenched glasses, confirm the amorphous nature of the glasses present. Also, the overall features of X-ray diffraction (XRD) confirm the amorphous nature of the present glasses. Transmission electron micrograph (TEM) and XRD of the corresponding heat treated sample indicate nanocrystals with a particle size of 20-35 nm. It was found that density (d) increases gradually with the increase of the BaTiO{sub 3} content in the nanocrystalline glass-ceramics. It is observed that the conductivity of the nanocrystalline glass-ceramics is higher than that of the corresponding glassy phase. The high conductivity of these nanocrystalline glass-ceramics is considered to be due to the presence of nanocrystals with a particle size of 20-35 nm. This is attributed to the formation of extensive and dense network of electronic conduction paths which are situated between V{sub 2}O{sub 5} nanocrystals and on their surface. The electrical conductivity of this system can be fitted with Mott's model of nearest neighbor hopping at high temperature. From the best fits, reasonable values of various small polaron hopping (SPH) parameters are obtained. From dielectric permittivity of the as-cast glass samples, no ferroelectric behavior can be observed. Also, the dielectric permittivity (epsilon) values of these glasses are found to be very high compared to familiar vanadium containing glasses. By annealing the glass system around 450 deg. C for 1 h in air, nanocrystalline BaTiO{sub 3} phase precipitates and the corresponding nanocrystalline glass-ceramics showed average broad peak around 352 K in the dielectric permittivity (epsilon). It is interesting to note that pure nanocrystalline BaTiO{sub 3} phase with average particle size less than 100 nm also

  12. Coexistence of considerable inter-particle interactions and spin-glass behavior in La{sub 0.7}Ca{sub 0.3}MnO{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Thanh, T. D., E-mail: thanhxraylab@yahoo.com [Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Institute of Materials Science, VAST, 18-Hoang Quoc Viet, Hanoi (Viet Nam); Manh, D. H.; Phuc, N. X. [Institute of Materials Science, VAST, 18-Hoang Quoc Viet, Hanoi (Viet Nam); Phan, T. L.; Yu, S. C., E-mail: scyu@chungbuk.ac.kr [Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Phong, P. T. [Nha Trang Pedagogic College, 1 Nguyen Chanh Street, Nha Trang (Viet Nam); Hung, L. T. [Department of Physics, University of Vinh, Nghe An (Viet Nam)

    2014-05-07

    We have studied the magnetic and spin-glass (SG) properties of La{sub 0.7}Ca{sub 0.3}MnO{sub 3} single-crystalline nanoparticles, which were prepared by the mechanical milling method with different milling times (t{sub m}). Analyzing the susceptibility data in the paramagnetic region indicates both ferromagnetic (FM) and anti-FM interactions coexisting in nanoparticles. Additionally, there is a peak associated with the freezing temperature (T{sub f}) appearing on the real part curve of the ac susceptibility, χ′(T). The T{sub f} value increases with increasing frequency as expected for SG systems. The SG behavior was also checked by using the criterion parameter c = ΔT{sub f}/T{sub f}Δ(log{sub 10}f), and the power law τ = τ{sub 0}(T/T{sub g} − 1){sup −zν}. The obtained values of c ≈ 5 × 10{sup −2}, τ{sub 0} ≈ 10{sup −5} s and zν ≈ 2–3 are consistent with those expected for SG-like systems, suggesting an existence of a SG phase transition at T{sub g} below T{sub f}, which decreases with decreasing 〈D〉. Basing on ln(f) versus T{sub f} data, and the Néel-Arrhenius model [ln(f) = ln(f{sub 0}) - E{sub a}/k{sub B}T] and Vogel–Fulcher law [ln(f) = ln(f{sub 0}) - E{sub a}/k{sub B}(T - T{sub 0})], the Larmor frequency (f{sub 0}), activation energy (E{sub a}) and effective temperature (T{sub 0}) for the samples with different 〈D〉 were determined. Obtained results indicate the existence a strong interaction between nanoparticles.

  13. Y{sub 2}O{sub 3}: Dy{sup 3+}/Li{sup +} phosphors synthesized by spray

    Energy Technology Data Exchange (ETDEWEB)

    Balderas X, R.; Carmona T, S.; Falcony, C., E-mail: scarmonat81@gmail.com [IPN, Centro de Investigacion y de Estudios Avanzados, Apdo. Postal 14-740, 07000 Ciudad de Mexico (Mexico)

    2017-11-01

    Dysprosium and lithium-activated yttrium oxide phosphor was synthesized at 1100 degrees Celsius by ultrasonic spray pyrolysis (Usp) using Di water as solvent and metal chlorides as precursors. The characteristic emission peak of Dy{sup 3+} due to the transitions {sup 4}F{sub 9/2} to {sup 6}H{sub 15/2} at 483 nm, {sup 4}F{sub 9/2} to {sup 6}H{sub 13/2} at 573 nm, {sup 4}F{sub 9/2} to {sup 6}H{sub 11/2} at 667 nm and {sup 4}F{sub 9/2} to {sup 6}H{sub 9/2} at 766 nm were observed. Scanning electron microscopy and transmission electron microscopy measurements were carried out to understand surface morphological features and the particle size of the phosphor. The uniformity of phase of Dy{sup 3+} - Li{sup +} doped Y{sub 2}O{sub 3} phosphors was checked by X-ray diffraction technique. The phosphors form clusters that were found to be ∼ 1 μm in size, however, particles that form these clusters have sizes between 40 and 120 nm. (Author)

  14. Effects of size reduction on the structure and magnetic properties of core–shell Ni{sub 3}Si/silica nanoparticles prepared by electrochemical synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Pigozzi, Giancarlo, E-mail: giancarlo.pigozzi@empa.ch [Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf (Switzerland); Mukherji, Debashis, E-mail: d.mukherji@tu-bs.de [Institut für Werkstoffe, Technical University of Braunschweig, Langer Kamp 8, 38106 Braunschweig (Germany); Elerman, Yalçin, E-mail: Yalcin.Elerman@ankara.edu.tr [Department of Engineering Physics, Faculty of Engineering, Ankara University, 06100 Besevler, Ankara (Turkey); Strunz, Pavel, E-mail: strunz@ujf.cas.cz [Nuclear Physics Institute (NPI), 25068 Řež (Czech Republic); Gilles, Ralph, E-mail: Ralph.Gilles@frm2.tum.de [Technische Universität München, Forschungs-Neutronenquelle Heinz Maier-Leibnitz (MLZ), 85747 Garching (Germany); Hoelzel, Markus, E-mail: markus.hoelzel@frm2.tum.de [Technische Universität München, Forschungs-Neutronenquelle Heinz Maier-Leibnitz (MLZ), 85747 Garching (Germany); Barbier, Bruno, E-mail: b.barbier@uni-bonn.de [Steinmann Institut, Poppelsdorfer Schloss, 53115 Bonn (Germany); Schmutz, Patrik [Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf (Switzerland)

    2014-01-25

    Highlights: • β{sub 1}-Ni{sub 3}Si nanoparticles were produced by electrochemical selective phase dissolution. • A core–shell structure with ordered Ni{sub 3}Si core and silica shell is obtained. • The ordered L1{sub 2} crystal structure is maintained upon size reduction down to 20 nm. • Bulk Ni{sub 3}Si is ferromagnetic below 260 K with low saturation magnetization (2 emu/g). • Nanoparticles are superparamagnetic (T{sub B} ∼ 9–11 K) with magnetization >20 emu/g. -- Abstract: Nanostructured nickel silicides find application in electronics, high-temperature alloys, electrode materials and catalysis. In this work, the effect of size reduction on the structure and magnetic properties of β{sub 1}-Ni{sub 3}Si intermetallic phase nanoparticles is studied. Electrochemical selective phase dissolution (ESPD) was used to produce the β{sub 1}-Ni{sub 3}Si nanoparticles of different sizes (from 20 to 215 nm) by extracting β{sub 1} nano-size precipitates from two-phase Ni–Si and Ni–Si–Al precursor alloys. The extracted nanoparticles have a core–shell structure with β{sub 1}-Ni{sub 3}Si core and an amorphous silica shell. Particles size and shape are controlled by the composition and thermal treatment of the precursor alloys. Precipitates size is scaled without modifying the ordered L1{sub 2} lattice structure. The bulk β{sub 1}-Ni{sub 3}Si is ferromagnetic below 260 K with low saturation magnetization (2 emu/g), while the core–shell Ni{sub 3}Si/silica nanoparticles are superparamagnetic at low temperatures (<9–11 K) with low coercivity (<90 Oe) and magnetization >20 emu/g at 5 T. It is suggested that weak particle magnetic moments and low magnetic anisotropy of the L1{sub 2} structure are responsible for these properties. The shell on one hand protects the core from degradation; however the oxidation of the core/shell interface region can influence the magnetic behavior of the nano-powders.

  15. Facile hydrothermal fabrication of nitrogen-doped graphene/Fe{sub 2}O{sub 3} composites as high performance electrode materials for supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Penghui; Li, Weilong, E-mail: lwl@nwu.edu.cn; Wang, Gang; Yu, Baozhi; Li, Xiaojun; Bai, Jintao; Ren, Zhaoyu, E-mail: rzy@nwu.edu.cn

    2014-08-01

    Highlights: • Nitrogen-doped graphene/Fe{sub 2}O{sub 3} composites (NGFeCs) have been synthesized simply. • Fe{sub 2}O{sub 3} particles with size about 20–100 nm were homogenously anchored on NG sheets. • The as-prepared NGFeCs were firstly used as electrode materials for supercapacitor. • The as-prepared NGFeCs electrode shows excellent electrochemical performance. - Abstract: Nitrogen-doped graphene/Fe{sub 2}O{sub 3} composites (NGFeCs) have been synthesized by a simple hydrothermal method. The structure and morphology of the samples were analyzed by X-ray diffraction, Raman spectra, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. The results indicate that Fe{sub 2}O{sub 3} particles with size about 20–100 nm were homogenously anchored on nitrogen-doped graphene (NG) sheets. Electrochemical properties of the synthesized materials were characterized by serials of electrochemical measurements in 1 M Na{sub 2}SO{sub 4} electrolyte. The as-prepared NGFeCs show a better electrochemical performance than the graphene/Fe{sub 2}O{sub 3} composites (GFeCs). The specific capacitance of NGFeCs electrode is 260.1 F/g (150.4 F/g for GFeCs electrode) at a current density of 2 A/g. Additionally, over 82.5% (214.6 F/g) of the original capacitance is retained after 1000 cycles at a current density of 2 A/g (61.4% for GFeCs electrode). The superior electrochemical performance can be ascribed to the good electronic conductivity and more active and nucleation sites introduced by the nitrogen-doping (especially by pyrrolic N-doping)

  16. Catalytic cartridge SO/sub 3/ decomposer

    Science.gov (United States)

    Galloway, T.R.

    1980-11-18

    A catalytic cartridge surrounding a heat pipe driven by a heat source is utilized as a SO/sub 3/ decomposer for thermochemical hydrogen production. The cartridge has two embodiments, a cross-flow cartridge and an axial flow cartridge. In the cross-flow cartridge, SO/sub 3/ gas is flowed through a chamber and incident normally to a catalyst coated tube extending through the chamber, the catalyst coated tube surrounding the heat pipe. In the axial-flow cartridge, SO/sub 3/ gas is flowed through the annular space between concentric inner and outer cylindrical walls, the inner cylindrical wall being coated by a catalyst and surrounding the heat pipe. The modular cartridge decomposer provides high thermal efficiency, high conversion efficiency, and increased safety. A fusion reactor may be used as the heat source.

  17. Fabrication of AgFeO{sub 2}/g-C{sub 3}N{sub 4} nanocatalyst with enhanced and stable photocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Dandan [School of Resources and Environmental Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China); Hubei Provincial Collaborative Innovation Center for High Efficient Utilization of Vanadium Resources, Wuhan 430070 (China); Zhang, Gaoke, E-mail: gkzhang@whut.edu.cn [School of Resources and Environmental Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China); Hubei Provincial Collaborative Innovation Center for High Efficient Utilization of Vanadium Resources, Wuhan 430070 (China)

    2017-01-01

    Highlights: • AgFeO{sub 2}/g-C{sub 3}N{sub 4} nanocatalyst was synthesized via a facile precipitation method. • The composite displays superior e{sup ∧}/h{sup +} pair separation compared to AgFeO{sub 2} and g-C{sub 3}N{sub 4}. • The composite shows high and stable photocatalytic activity both in water and air. • The active h{sup +} plays the dominate role in the degradation process. - Abstract: This work reported a novel AgFeO{sub 2}/g-C{sub 3}N{sub 4} composite with enhanced photocatalytic activity, which was fabricated by a simple precipitation method. The g-C{sub 3}N{sub 4} sheets with thickness of 2• 4 nm were successfully loaded on the surface of the AgFeO{sub 2} particles. As compared to pure AgFeO{sub 2} and pure g-C{sub 3}N{sub 4}, the as-prepared AgFeO{sub 2}/g-C{sub 3}N{sub 4} photocatalysts exhibited superior absorption in the visible-light region and displayed promising visible-light photocatalytic performance in the degradation of organic contaminations both in water and in air. About 94% of Acid red G (ARG) can be degraded by the optimized AgFeO{sub 2}/g-C{sub 3}N{sub 4} sample, which is ∱/47.5 and ∱/410.7 times higher than that by pure AgFeO{sub 2} and pure g-C{sub 3}N{sub 4}, respectively. Meanwhile, it can also effectively degrade ∱/487% of gaseous formaldehyde to CO{sub 2} within 9 h. The enhanced photocatalytic property and stability of the AgFeO{sub 2}/g-C{sub 3}N{sub 4} composite can be attributed to its specific nanostructure, effective electron-hole separation and the formation of Z-scheme heterostructure between AgFeO{sub 2} and g-C{sub 3}N{sub 4}. This work could provide new and helpful insights into the photocatalytic application of Ag-based delafossite materials.

  18. Spectral properties and laser performances of Yb{sup 3+}:LaCa{sub 4}O(BO{sub 3}){sub 3} crystal with high concentration doping

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Yuexia, E-mail: tcy@fjirsm.ac.cn [Key Laboratory of Photoelectric Materials Chemistry and Physics of CAS, Fujian Institute of Research on the Structure of Matter, University of Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); University of Chinese Academy of Sciences, Beijing City 100039 (China); Cao, Jiafeng; Xu, Jinlong; You, Zhenyu; Zhu, Zhaojie; Li, Jianfu; Wang, Yan; Tu, Chaoyang [Key Laboratory of Photoelectric Materials Chemistry and Physics of CAS, Fujian Institute of Research on the Structure of Matter, University of Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)

    2013-11-05

    Highlights: •Yb{sup 3+}:LaCa{sub 4}O(BO{sub 3}){sub 3} single crystal was grown with high concentration doping. •Laser potentiality was evaluated based on the spectral and laser parameters. •Continuous wave laser operation was realized. •An output power of 0.77 W and a slope efficiency of 15.71% at 1077 nm were obtained. •The spectra and laser properties of Yb{sup 3+}:LaCa{sub 4}O(BO{sub 3}){sub 3} crystal were firstly reported. -- Abstract: High concentration of 15 at.% Yb{sup 3+} doped LaCa{sub 4}O(BO{sub 3}){sub 3} (LaCOB) crystal was grown by Czochralski technique. The absorption cross section was conclulated to be 0.63 × 10{sup −20} cm{sup 2} at 977 nm and the emission cross section to be 0.39 × 10{sup −20} cm{sup 2} at 1030 nm, with the FWHM of 6.15 and 33 nm respectively. Laser potentiality was evaluated based on the gain cross section σ{sub g}, the minimum inversion fraction β{sub min} and the minimum pump intensity I{sub min}, which were calculated to be 0.18 × 10{sup −20} cm{sup 2}, 0.05 and 0.47 kw/cm{sup 2}, respectively. Continuous wave laser operation was realized with an output power of 0.77 W and a slope efficiency of 15.71%. The laser emitted around 1077 nm. The radiation trapping and continuous pump mode are contributed to the lasing wavelength for present crystal.

  19. The energy level alignment at the CH{sub 3}NH{sub 3}PbI{sub 3}/pentacene interface

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Gengwu [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204 (China); University of Chinese Academy of Science, Beijing 100049 (China); Zhao, Bin; Song, Fei [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204 (China); Zheng, Guanhaojie; Zhang, Xiaonan [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204 (China); University of Chinese Academy of Science, Beijing 100049 (China); Shen, Kongchao [Department of Physics, Zhejiang University, Hangzhou 310027 (China); Yang, Yingguo [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204 (China); Chen, Shi, E-mail: ChenShi@ntu.edu.sg [Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371 (Singapore); Gao, Xingyu, E-mail: gaoxingyu@sinap.ac.cn [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204 (China)

    2017-01-30

    Highlights: • The Energy Level Alignment at the CH{sub 3}NH{sub 3}PbI{sub 3}/Pentacene Interface was resolved experimentally. • The downward band bending and the dipole found at the pentacene side would favorably drive holes away from the interface into pentacene. • A ∼0.7 eV offset between pentacene HOMO and CH{sub 3}NH{sub 3}PbI{sub 3} VBM would be in favor of hole transfer whereas a ∼1.35 eV offset between pentacene LUMO and CH{sub 3}NH{sub 3}PbI{sub 3} CBM should efficiently block the unwanted electron transfer from perovskite to pentacene. • Pentacene could be a viable hole transfer material candidate on perovskite to be explored in perovskite devices. - Abstract: Pentacene thin film on CH{sub 3}NH{sub 3}PbI{sub 3} was studied by in-situ X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy to determine their interfacial energy level alignment. A 0.2 eV downward band bending together with a 0.1 eV interfacial dipole was found at the pentacene side, whereas there was no band bending found at the CH{sub 3}NH{sub 3}PbI{sub 3} side. The offset between CH{sub 3}NH{sub 3}PbI{sub 3} Valance Band Maximum (VBM) and pentacene Highest Occupied Molecular Orbital (HOMO) and that between CH{sub 3}NH{sub 3}PbI{sub 3} Conduction Band Minimum (CBM) and pentacene Lowest Unoccupied Molecular Orbital (LUMO) was determined to be 0.7 and 1.35 eV, respectively. The band alignment at this interface is favor of efficient hole transfer, which suggests pentacene as a viable HTL candidate to be explored in perovskite solar cells.

  20. Growth and characterization of a LaCa{sub 4}O(BO{sub 3}){sub 3} crystal

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H.J.; Jiang, H.D.; Wang, J.Y.; Hu, X.B.; Yu, G.W.; Yu, W.T.; Gao, L.; Zhang, S.J.; Jiang, M.H. [National Laboratory of Crystal Materials and Institute of Crystal Materials, Shandong University, 250100, Jinan (China); Liu, J.A. [Department of Material Science and Engineering, Institute of Shandong Light Industry, 250100, Jinan (China)

    2004-03-01

    The non-linear optical (NLO) crystal LaCa{sub 4} O(BO{sub 3}){sub 3} (LaCOB) has been grown by the Czochralski method. X-ray diffraction experiments show that LaCOB crystal possesses the space group Cm, and its unit cell constants have been measured to be a=0.8168(3) nm,b=1.6081(7) nm and c=0.3630(6) nm, with an angle {beta}=101.39 . The thermal properties of LaCOB have been studied; the specific heat of the crystal is 321.9 J/mol K at 330 K, and the three principal coefficients of thermal expansion of the principal axes have been calculated from the measured data to be 5.61 x 10{sup -6} K{sup -1}, 7.21 x 10{sup -6} K{sup -1} and 11.01 x 10{sup -6} K{sup -1}, respectively. The transmission spectrum shows that LaCOB crystal has a wide transparency wavelength range, and may be used as a NLO crystal. (orig.)

  1. Particle size effect on microwave absorbing of La{sub 0.67}Ba{sub 0.33}Mn{sub 0.94}Ti{sub 0.06}O{sub 3} powders prepared by mechanical alloying with the assistance of ultrasonic irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Saptari, Sitti Ahmiatri, E-mail: siti-ahmiatri@yahoo.co.id [Faculty of Science and Technology, State Islamic University, Jakarta (Indonesia); Manaf, Azwar; Kurniawan, Budhy [Departement of Physics, University of Indonesia, Depok (Indonesia)

    2016-03-11

    Doped manganites have attracted substantial interest due to their unique chemical and physics properties, which makes it possible to be used for microwave absorbing materials. In this paper we report synthesizes and characterization of La{sub 0.67}Ba{sub 0.33}Mn{sub 0.94}Ti{sub 0.06}O{sub 3} powders prepared by mechanical alloying with the assistance of a high power ultrasonic treatment. After solid state reaction, the presence of single phase was confirmed by X-ray Diffraction (XRD). Refinement results showed that samples are single phase with monoclinic structure. It was found that powder materials derived from mechanical alloying results in large variation in the particle size. A significant improvement was obtained upon subjecting the mechanically milled powder materials to an ultrasonication treatment for a relatively short period of time. As determined by particle size analyzer (PSA), the mean particle size gradually decreased from the original size of 5.02 µm to 0.36 µm. Magnetic properties were characterized by VSM, and hysteresis loops results showed that samples are soft magnetic. It was found that when the mean particle size decreases, saturation was increases and coersitivity was decreases. Microwave absorption properties were investigated in the frequency range of 8-12 GHz using vector network analyzer. An optimal reflection loss of 24.44 dB is reached at 11.4 GHz.

  2. Photodissociation thresholds of OH produced from CH sub 3 OH in solid neon and argon

    CERN Document Server

    Cheng, B M; Lo, W J; Lee, Y P

    2001-01-01

    Photodissociation thresholds of OH from CH sub 3 OH in solid Ne and Ar were determined via photolysis of CH sub 3 OH/Ne and CH sub 3 OH/Ar (1/200) samples in situ at 4 K. The samples were irradiated with VUV synchrotron radiation after dispersion by a Seya-Namioka monochromator. The OH photo-product was detected by means of laser-induced fluorescence technique. The increase of fluorescent intensity of OH was monitored and recorded after the matrix sample was irradiated at different wavelengths for 3-5 min. Photodissociation threshold energies of 7.13+-0.02 eV (174.0+-0.5 nm) and 7.08+-0.04 eV (175.0+-1.0 nm) were measured for OH production of CH sub 3 OH in solid Ne and Ar, respectively.

  3. Chemically deposited Sb{sub 2}S{sub 3} thin films for optical recording

    Energy Technology Data Exchange (ETDEWEB)

    Shaji, S; Arato, A; Castillo, G Alan; Palma, M I Mendivil; Roy, T K Das; Krishnan, B [Facultad de IngenierIa Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, San Nicolas de los Garza, Nuevo Leon, C.P- 66450 (Mexico); O' Brien, J J; Liu, J, E-mail: bkrishnan@fime.uanl.m [Center for Nanoscience and Department of Chemistry and Biochemistry, University of Missouri-St. Louis, One Univ. Blvd., St. Louis, MO - 63121 (United States)

    2010-02-24

    Laser induced changes in the properties of Sb{sub 2}S{sub 3} thin films prepared by chemical bath deposition are described in this paper. Sb{sub 2}S{sub 3} thin films of thickness 550 nm were deposited from a solution containing SbCl{sub 3} and Na{sub 2}S{sub 2}O{sub 3} at 27 {sup 0}C for 5 h. These thin films were irradiated by a 532 nm continuous wave laser beam under different conditions at ambient atmosphere. X-ray diffraction analysis showed amorphous to polycrystalline transformation due to laser exposure of these thin films. Morphology and composition of these films were described. Optical properties of these films before and after laser irradiation were analysed. The optical band gap of the material was decreased due to laser induced crystallization. The results obtained confirm that there is further scope for developing this material as an optical recording media.

  4. Synthesis of sealed sponge ZnO nanospheres through a novel NH{sub 3}-evaporation method

    Energy Technology Data Exchange (ETDEWEB)

    Cheng Lihong; Zheng Liaoying; Li Guorong; Yin Qingrui [State Key Laboratory of High Performance Ceramics and Superfine Structure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Jiang, Kyle [Department of Mechanical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)], E-mail: grli@sunm.shcnc.ac.cn

    2008-02-20

    Sealed sponge ZnO nanospheres are prepared through a novel NH{sub 3}-evaporation method. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM) and N{sub 2} physisorption analysis show that the samples obtained are ZnO nanospheres with hexagonal wurtzite structure. The particle size is in the range 80-130 nm and the pores inside are estimated to be in the range 2-35 nm. During the preparation process, the carboxyls derived from the polyacrylamide hydrolyzation tend to attach to the particle surface and bring about the interaction between particles by hydrogen bonding. Results show that the polyacrylamide and alcohol are crucial to the formation of the sealed sponge ZnO, by forming a diffusion layer around the particle. The formation mechanism is considered to be controlled by the diffusion of Zn{sup 2+} through the diffusion layer, and the mass transmission between the initial particles.

  5. Blue and red emission in wide band gap BaZrO{sub 3}:Yb{sup 3+},Tm{sup 3+}

    Energy Technology Data Exchange (ETDEWEB)

    Borja-Urby, R. [Centro de Investigaciones en Optica, A. C., C. P. 37150 Leon, Gto. (Mexico); Diaz-Torres, L.A., E-mail: ditlacio@cio.mx [Centro de Investigaciones en Optica, A. C., C. P. 37150 Leon, Gto. (Mexico); Salas, P. [Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico, A. P. 1-1010, Queretaro 76000 (Mexico); Vega-Gonzalez, M. [Centro de Geociencias-Universidad Nacional Autonoma de Mexico, A. P. 1-1010, Queretaro 76000 (Mexico); Angeles-Chavez, C. [Instituto Mexicano del Petroleo, Programa de Ingenieria Molecular, Cd. Mexico D.F. 07730 (Mexico)

    2010-10-25

    Under NIR excitation at 967 intense blue and red photoluminescence (PL) emissions are observed at room temperature in codoped Tm{sup 3+}-Yb{sup 3+} barium zirconate (BaZrO{sub 3}:Yb,Tm) powders. Powders were prepared by a simple hydrothermal method, and present a wide band gap that depends on the total rare earth content due to the degree of disorder induced in the BaZrO{sub 3} lattice by the substitution of the rare earth ions. Rietveld refinements of the XRD patterns indicated the presence of primary nanocrystallites with sizes between 50 and 70 nm depending on the Tm{sup 3+} content. Scanning transmission electron microscopy (STEM) shows that these primary particles self-aggregated in larger secondary particles which present a regular morphology with sizes around 1 {mu}m. The intense blue and red PL emissions in BaZrO{sub 3} powders under 967 nm excitation are governed by energy transfer processes from Yb{sup 3+} ions to Tm{sup 3+} ions and crossrelaxation among Tm{sup 3+} ions.

  6. Synthesis and electrochemical study of Mg{sub 1.5}MnO{sub 3}: A defect spinel cathode for rechargeable magnesium battery

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Partha [Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); US Department of Energy, National Energy Technology Laboratory, Morgantown, WV 26507 (United States); Jampani, Prashanth H., E-mail: pjampani@pitt.edu [Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); Hong, DaeHo [Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); Gattu, Bharat [Mechanical Engineering and Materials Science, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); Poston, James A.; Manivannan, Ayyakkannu [US Department of Energy, National Energy Technology Laboratory, Morgantown, WV 26507 (United States); Datta, Moni Kanchan [Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); US Department of Energy, National Energy Technology Laboratory, Morgantown, WV 26507 (United States); Kumta, Prashant N., E-mail: pkumta@pitt.edu [Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); US Department of Energy, National Energy Technology Laboratory, Morgantown, WV 26507 (United States); Mechanical Engineering and Materials Science, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); Chemical and Petroleum Engineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); School of Dental Medicine, University of Pittsburgh, PA 15261 (United States); Center for Complex Engineered Multifunctional Materials, University of Pittsburgh, Pittsburgh, PA 15261 (United States)

    2015-12-15

    Graphical abstract: Mg{sub 1.5}MnO{sub 3}, a defect oxide spinel derived by the Pechini route, was tested as cathode for rechargeable magnesium battery. TEM and XRD analyses of Mg{sub 1.5}MnO{sub 3} shows the formation of ∼100 nm sized nano particles in the cubic defect spinel structure (space group: Fd3m; unit cell: 0.833294 nm). Cyclic voltammetry illustrates a reversible reaction occurring between 0.3 and 1.5 V versus magnesium. Galvanostatic cycling of the Mg{sub 1.5}MnO{sub 3} cathode exhibits a low capacity of ∼12.4 mAh/g up to 20 cycle with ∼99.9% Coulombic efficiency when cycled at a current rate of ∼C/27. XPS (X-ray photoelectron spectroscopy) surface probe of magnesiated/de-magnesiated electrodes confirm a change in the redox center of Mn-ions during intercalation/de-intercalation of Mg-ion from the Mg{sub 1.5}MnO{sub 3} electrode. The low capacity of Mg{sub 1.5}MnO{sub 3} electrode mainly stem from the kinetic limitation of Mg-ion removal from the defect oxide spinel as the electrochemical impedance spectroscopy results of electrodes after 1st and 2nd cycle show that charge transfer resistance, R{sub e}, increases post charge state whereas interfacial resistance, R{sub i}, increases after discharge state, respectively. - Highlights: • Pechini process yields 100 nm sized particles of the defect cubic spinel Mg{sub 1.5}MnO{sub 3}. • Stable capacity of ∼12.4 mAh/g obtained at C/27 rate and 99.9% Coulombic efficiency. • XPS shows change in valence state of Mn{sup 3+}/Mn{sup 4+} center with cycling. • Low capacity stems from increase in charge-transfer and interfacial resistances with cycling. - Abstract: Mg{sub 1.5}MnO{sub 3}, a defect oxide spinel (space group: Fd3m; unit cell: 0.833294 nm) of particle size ∼100 nm derived by the Pechini route was tested as a cathode for rechargeable magnesium battery. Cyclic voltammetry illustrates a reversible reaction occurring in the 0.3–2.0 V potential window versus magnesium. The spinel however

  7. ITO-free organic light-emitting diodes with MoO{sub 3}/Al/MoO{sub 3} as semitransparent anode fabricated using thermal deposition method

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Hsin-Wei; Huang, Ching-Wen [Department of Electrical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Kao, Po-Ching [Department of Electrophysics, National Chiayi University, Chiayi 60004, Taiwan (China); Chu, Sheng-Yuan, E-mail: chusy@mail.ncku.edu.tw [Department of Electrical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, Taiwan (China)

    2015-08-30

    Highlights: • In this paper, the structure of the proposed devices is substrate (glass; polyethersulfone (PES))/anode (MoO{sub 3}/Al/MoO{sub 3}; MoO{sub 3}/Al)/α-naphthylphenylbiphenyl diamine (NPB) (40 nm)/tris (8-hydroxyquinoline) aluminum (Alq3) (60 nm)/LiF (1 nm)/Al (150 nm). • The optical transmittance of the metal layer was enhanced by depositing metal oxidation (MoO{sub 3}) and metal (Al) layers. • The optimized films show the typical sheet resistance of 7 Ω/sq and a high transmittance of 70% at 550 nm. • The indium-tin-oxide (ITO)-free OLEDs with the fabricated composite anodes on a glass substrate exhibited the high luminance and current efficiency of 21,750 cd/m{sup 2} and 3.18 cd/A, respectively. • The bending effects on PES substrate by depositing metal oxidation (MoO{sub 3}) and metal (Al) layers were also investigated. • MoO{sub 3} covering the Al layer modifies the surface of the electrode and enhances the durability. The surface roughness of the bi-layer films was higher than that of the tri-layer films. Therefore, OLEDs with OMO anode outperform those with bi-layer films anode. - Abstract: In this paper, semitransparent electrodes with the structure substrate/MoO{sub 3}/Al/MoO{sub 3} (OMO) were fabricated via the thermal deposition method for use as the anode in organic light-emitting diodes (OLEDs). The optical transmittance of the metal layer was enhanced by depositing metal oxidation (MoO{sub 3}) and metal (Al) layers. The optimal thickness of the Al thin films was determined to be 15 nm for high optical transmittance and good electrical conductivity. The optimized films show the typical sheet resistance of 7 Ω/sq and a high transmittance of 70% at 550 nm. The indium-tin-oxide (ITO)-free OLEDs with the fabricated composite anodes on a glass substrate exhibited the high luminance and current efficiency of 21,750 cd/m{sup 2} and 3.18 cd/A, respectively. In addition, bending effects on the polyethersulfone (PES) substrate/MoO{sub 3

  8. Magnetoelectric coupling-induced anisotropy in multiferroic nanocomposite (1 - x)BiFeO{sub 3}-xBaTiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Rekha; Shah, Jyoti [CSIR-National Physical Laboratory (India); Chaudhary, Sujeet [Indian Institute of Technology (India); Singh, Sukhbeer; Kotnala, Ravinder K., E-mail: rkkotnala@nplindia.org [CSIR-National Physical Laboratory (India)

    2013-10-15

    Nanocomposite (1 - x)BiFeO{sub 3}-xBaTiO{sub 3} for x = 0.1, 0.2 and 0.3 compositions were prepared by sol-gel technique. X-ray diffractograms confirmed the formation of desired crystallographic phase of the composite. The average particle size was determined 75, 128 and 150 nm for x = 0.1, 0.2 and 0.3 samples by HRTEM measurement. Magnetic, dielectric and magnetoelectric response has been investigated to find out the magnetoelectric (ME) coupling at atomic scale mixing of the two phases. For effective ME coupling nanoscale synthesis provided large surface area and subsequently induced magnetic anisotropy in the sample. The computed value of magnetic anisotropy constant 4.8 Multiplication-Sign 10{sup 3} erg/cm{sup 3} was found to be maximum for x = 0.1 composition. It is believed that the anisotropy is being induced by ME coupling which changes with the composition. Correlated magnetic and dielectric transition temperatures were determined as an evidence of ME coupling in the material. To confirm the ME coupling room-temperature ME coupling coefficient ({alpha}) was calculated using dynamic method which was observed to have a maximum value of 2.74 mV/cmOe for x = 0.1 confirming the presence of room-temperature ME coupling in the nanocomposite. Spin flipping behaviour has been confirmed by ZFC-FC measurements at low temperature while the coercivity was found to be almost constant. Significantly, controlled coercivity behaviour has been correlated to the presence of ME coupling in the composite material, which can be very useful in memory device and spintronic application.

  9. Fabrication and characterization of millimeter-scale translucent La{sub 2}O{sub 3}-doped Al{sub 2}O{sub 3} ceramic hollow spheres

    Energy Technology Data Exchange (ETDEWEB)

    Li, Haoting [School of Material Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, Sichuan (China); Liao, Qilong, E-mail: liaoqilong@swust.edu.cn [School of Material Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, Sichuan (China); Dai, Yunya [School of Material Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, Sichuan (China); Wang, Fu, E-mail: wfu2005@163.com [School of Material Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, Sichuan (China); Wang, Haiyang [School of Material Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, Sichuan (China); Li, Xibo [Research Center of Laser Fusion CAEP, Mianyang 621900, Sichuan (China)

    2016-04-15

    Highlights: • Millimeter-scale translucent La{sub 2}O{sub 3}-doped Al{sub 2}O{sub 3} hollow spheres have been prepared. • The diameters of the prepared hollow spheres are 500–1300μm. • The degree of sphericity for the prepared hollow spheres is above 98%. • The mechanisms of transparency are discussed. - Abstract: Millimeter-scale translucent La{sub 2}O{sub 3}-doped Al{sub 2}O{sub 3} ceramic hollow spheres have been successfully prepared using the oil-in-water (paraffin-in-alumina sol) droplets as precursors made by self-made T-shape micro-emulsion device. The main crystalline phase of the obtained hollow sphere is alpha alumina. The prepared translucent La{sub 2}O{sub 3}-containing Al{sub 2}O{sub 3} ceramic hollow spheres have diameters of 500–1300 μm, wall thickness of about 23 μm and the degree of sphericity of above 98%. With the increase of the La{sub 2}O{sub 3} content, grains and grain-boundaries of the alumina spherical shell for the prepared millimeter-scale hollow spheres become regular and clear gradually. When the La{sub 2}O{sub 3} content is 0.1 wt.%, the crystal surface of the obtained Al{sub 2}O{sub 3} spherical shell shows optimal grains and few pores, and its transmittance reaches 42% at 532 nm laser light. This method provides a promising technique of preparing millimeter-scale translucent ceramic hollow spheres for laser inertial confined fusion.

  10. Transparent CH{sub 3}NH{sub 3}SnCl{sub 3}/Al-ZnO p-n heterojunction diode

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Sunil, E-mail: skbgudha@gmail.com; Ansari, Mohd Zubair; Khare, Neeraj [Department of Physics, Indian Institute of Technology, Hauz Khas, New Delhi, Delhi-110016 (India)

    2016-05-23

    A p-type Organic inorganic tin chloride (CH{sub 3}NH{sub 3}SnCl{sub 3}) perovskite thin film has been synthesized by solution method. An n-type 1% Al doped ZnO (AZO) film has been deposited on FTO substrate by ultrasonic assisted chemical vapor deposition technique. A transparent CH{sub 3}NH{sub 3}SnCl{sub 3}/AZO p-n heterojunction diode has been fabricated by spin coating technique. CH{sub 3}NH{sub 3}SnCl{sub 3}/AZO p-n heterojunction shows 75% transparency in the visible region. I-V characteristic of CH{sub 3}NH{sub 3}SnCl{sub 3}/AZO p-n heterojunction shows rectifying behavior of the diode. The diode parameters calculated as ideality factor η=2.754 and barrier height Φ= 0.76 eV. The result demonstrates the potentiality of CH{sub 3}NH{sub 3}SnCl{sub 3}/AZO p-n heterojunction for transparent electronics.

  11. Optical and magnetic properties of Fe{sub 2}O{sub 3} nanoparticles synthesized by laser ablation/fragmentation technique in different liquid media

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, B.K., E-mail: bishnu.pandey750@gmail.com [Laser Spectroscopy and Nanomaterials Lab, Department of Physics (UGC-CAS), University of Allahabad, Allahabad 211002 (India); Shahi, A.K. [Laser Spectroscopy and Nanomaterials Lab, Department of Physics (UGC-CAS), University of Allahabad, Allahabad 211002 (India); Shah, Jyoti; Kotnala, R.K. [National Physical Laboratory (NPL), New Delhi (India); Gopal, Ram, E-mail: profrgopal@gmail.com [Laser Spectroscopy and Nanomaterials Lab, Department of Physics (UGC-CAS), University of Allahabad, Allahabad 211002 (India)

    2014-01-15

    Iron oxide (Fe{sub 2}O{sub 3}) bulk powder have been ablated/fragmented in different liquid medium by Nd:YAG laser beam using 1064 nm wavelength. Sodium dodecyl sulfate (SDS), cetyltrimethyl ammonium bromide (CTAB) and double distilled water (DDW) are used as liquid medium. Crystalline size, lattice strain, phase and structure of ablated particles have been investigated using synchrotron X-ray diffraction. Optical band gap energy of as purchased Fe{sub 2}O{sub 3} found 1.92 eV that increased to 2.03 eV after ablation in CTAB determined by UV–vis absorption spectroscopy. Magnetic properties have been analyzed by hysteresis loops using vibrating sample magnetometer (VSM). Crystalline sizes have been found in the range of 29.23–16.54 nm and coercivity tailored in the range of 206.91–298.36 Oe using laser ablation. Saturation magnetization and remanence have been found in the range of 0.013–3.41 emu/g and 0.0023–.0.51 emu/g respectively. Particle shape and size have been examined by scanning electron microscopy (SEM). CTAB (cationic) and SDS (anionic) surfactants are used as capping agent. CTAB produces phase transformation in ablated iron oxide (Fe{sub 2}O{sub 3}). Crystallinity and crystalline size of ablated particles in DDW increased due to presence of rich oxygen in it due to oxidation. Ablated Fe{sub 2}O{sub 3} nanoparticles have been widely used experimentally for numerous in vivo applications such as MRI contrast enhancement agent, tissue repair, immunoassay, detoxification of biological fluids, hyperthermia, drug delivery and cell separation.

  12. Mössbauer studies of stoichiometry of Fe{sub 3}O{sub 4}: characterization of nanoparticles for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, C. E., E-mail: cjohnson@utsi.edu; Johnson, J. A.; Hah, H. Y.; Cole, M.; Gray, S. [University of Tennessee Space Institute, Center for Laser Applications (United States); Kolesnichenko, V. [Xavier University, Department of Chemistry (United States); Kucheryavy, P. [Rutgers University, Department of Chemistry (United States); Goloverda, G. [Xavier University, Department of Chemistry (United States)

    2016-12-15

    The iron oxide Fe{sub 3}O{sub 4}, the mineral magnetite sometimes called ferrosoferric oxide, is notoriousy non-stoichiometric even in bulk form so its formula may be written Fe{sub 3−δ}O{sub 4}. In nanoparticle form, where it has applications in medicine and information technology, it is even more susceptible to oxidation. In this paper we report synthesis and studies of superparamagnetic Fe{sub 3}O{sub 4} nanoparticles with controlled diameters of 5.3, 10.6 and 11.9 nm. In room temperature spectra, departures from stoichiometry δ of up to 0.02 were estimated from the relative amounts of Fe {sup 3+}/ Fe {sup 2+} and from their isomer shifts. This cannot be used for very small particles of diameter 10.6 nm and less as they are superparamagnetic at room temperature and do not show hyperfine splitting owing to fast relaxation. Such particles have promise for use in enhancing MRI signals. The magnetic spectrum is restored by the application of a relatively small magnetic field (10 kG). As the temperature is lowered the relaxation slows down and 6-line magnetic hyperfine patterns appear below a blocking temperature T{sub B}. The values of T{sub B} obtained are lower than those of many other researchers reported in the literature, suggesting that our particles are less affected by magnetic interactions between them. At low temperatures all the spectra are similar and closely resemble that of bulk Fe{sub 3}O{sub 4} confirming that departures from stoichiometry are small.

  13. Optical and magnetic properties of La{sub 1−x}Ga{sub x}FeO{sub 3} nanoparticles synthesized by polymerization complex method

    Energy Technology Data Exchange (ETDEWEB)

    Hunpratub, Sitchai [Department of Physics, Faculty of Science, Udon Thani Rajabhat University, Udon Thani 41000 (Thailand); Karaphun, Attaphol [Nanotec-KKU Center of Excellence on Advanced Nanomaterials for Energy Production and Storage, Khon Kaen 40002 (Thailand); Phokha, Sumalin [Department of Physics, Faculty of Science, Udon Thani Rajabhat University, Udon Thani 41000 (Thailand); Swatsitang, Ekaphan, E-mail: ekaphan@kku.ac.th [Integrated Nanotechnology Research Center, Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Nanotec-KKU Center of Excellence on Advanced Nanomaterials for Energy Production and Storage, Khon Kaen 40002 (Thailand)

    2016-09-01

    Graphical abstract: This figure shows the hysteresis loops of LaFeO{sub 3} and La{sub 0.6}Ga{sub 0.4}FeO{sub 3} nanoparticles with corresponding TEM images. Undoped sample exhibits antiferromagnetic behavior, whereas doped sample becomes ferromagnetic material. Particle sizes estimated by TEM are decreased from 70.2 ± 4.5 to 21.4 ± 8.5 nm with increasing Ga content. The decrease of particle size causes the disordering spins at the surface of particle which can induce a net magnetic moment and significantly enhance the magnetization (M), coercive field (H{sub c}) and remanent magnetization (M{sub r}). - Highlights: • Ga-doped LaFeO{sub 3} nanoparticles prepared by polymerization complex were studied. • Lattice, crystallite and particle size of sample decrease with increasing Ga content. • Decreasing of the lattice can distort the structure and enhance magnetic properties. • Optical band gaps of LaGaFeO{sub 3} nanoparticles are also decreased. • RT-FM of LaGaFeO{sub 3} nanoparticle is due to the disordering spins at surface particle. - Abstract: La{sub 1−x}Ga{sub x}FeO{sub 3} (x = 0.0, 0.1, 0.2, 0.3 and 0.4) nanoparticles were synthesized by polymerization complex method. X-ray diffraction (XRD) results reveal a pure orthorhombic phase structure. Increasing of Ga content, resulting in the decrease of average crystallite sizes calculated by XRD from 58.4 ± 5.9 to 13.4 ± 4.3 nm and the average particle sizes estimated by transmission electron microscope (TEM) images from 70.2 ± 4.5 to 21.4 ± 8.5 nm. The optical band gaps determined by UV–vis spectra showed a redshift from 2.145 to 1.954 eV that originates from surface effect caused by Ga substitution. The magnetic properties were investigated using a vibrating sample magnetometer (VSM). The room temperature hysteresis loops of La{sub 1–x}Ga{sub x}FeO{sub 3} nanopowders indicate the antiferromagnetic behavior of pure sample and all doped samples of ferromagnetic behavior with the enhancement of

  14. Hybrid molecular beam epitaxy for the growth of stoichiometric BaSnO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Prakash, Abhinav, E-mail: praka019@umn.edu; Dewey, John; Yun, Hwanhui; Jeong, Jong Seok; Mkhoyan, K. Andre; Jalan, Bharat, E-mail: bjalan@umn.edu [Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

    2015-11-15

    Owing to its high room-temperature electron mobility and wide bandgap, BaSnO{sub 3} has recently become of significant interest for potential room-temperature oxide electronics. A hybrid molecular beam epitaxy (MBE) approach for the growth of high-quality BaSnO{sub 3} films is developed in this work. This approach employs hexamethylditin as a chemical precursor for tin, an effusion cell for barium, and a radio frequency plasma source for oxygen. BaSnO{sub 3} films were thus grown on SrTiO{sub 3} (001) and LaAlO{sub 3} (001) substrates. Growth conditions for stoichiometric BaSnO{sub 3} were identified. Reflection high-energy electron diffraction (RHEED) intensity oscillations, characteristic of a layer-by-layer growth mode were observed. A critical thickness of ∼1 nm for strain relaxation was determined for films grown on SrTiO{sub 3} using in situ RHEED. Scanning transmission electron microscopy combined with electron energy-loss spectroscopy and energy dispersive x-ray spectroscopy confirmed the cube-on-cube epitaxy and composition. The importance of precursor chemistry is discussed in the context of the MBE growth of BaSnO{sub 3}.

  15. Studies of LaSn{sub 3} as a negative electrode for lithium ion batteries.

    Energy Technology Data Exchange (ETDEWEB)

    Vaughey, J. T.; Thackeray, M. M.; Shin, D.; Wolverton, C.; Northwestern Univ.

    2009-01-01

    The intermetallic compound LaSn{sub 3} has been explored as a possible negative electrode for lithium-ion batteries. A combination of experiment and density functional theory calculations provides evidence that the structure is intolerant to lithium insertion and that the electrochemical reaction occurs via a displacement mechanism. Experiment shows that approximately six Li react initially with LaSn{sub 3}; calculated energetics suggest that during the reaction La{sub 3}Sn{sub 5} and lithiated tin are formed and that the electrode operates by delithiation and relithiation of the Sn particles within an inert lanthanum-tin matrix. LaSn{sub 3} electrodes provide a reversible specific capacity of 200-250 mAh/g, whereas In-substituted electrodes that form a solid solution with LaSn{sub 3}, such as LaSn{sub 2.7}In{sub 0.3}, yield a slightly lower capacity.

  16. Composition-driven enhanced magnetic properties and magnetoelectric coupling in Gd substituted BiFeO{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Vijayasundaram, S.V., E-mail: vijayasundaramsv@gmail.com [Department of Physics, Presidency College, Chennai 600005 (India); Suresh, G. [Department of Physics, Park College of Engineering and Technology, Coimbatore 641659 (India); Department of Urology, Singapore General Hospital, Singapore 169856 (Singapore); Mondal, R.A. [Department of Physics, Hindustan University, Chennai 603103 (India); Kanagadurai, R. [Department of Physics, Presidency College, Chennai 600005 (India)

    2016-11-15

    Bi{sub 1-x}Gd{sub x}FeO{sub 3} (x=0, 0.05 and 0.1) samples were synthesized by modified sol–gel process. X-ray diffraction studies confirmed that the crystal structures of Gd substituted samples remain stable for x<0.1, while compositional-driven structural phase transition from rhombohedral to orthorhombic was observed in the case of x=0.1. The average particle sizes of pure and Gd substituted BiFeO{sub 3} nanoparticles were found to be in the range 62–46 nm. The size of the oblate spherical particles decreased with increasing Gd concentration. XPS studies revealed the trivalent oxidation states of Bi and Fe ions along with sample purity. Pure BiFeO{sub 3} exhibited linear M–H loop indicating its antiferromagnetic characteristics, whereas obvious non-linear M–H loops were observed in Gd substituted samples. In contrast to the observed room temperature magnetization (0.36 emu/g) under 40 kOe for BiFeO{sub 3}, the sample with 10% Gd exhibited appreciable enhancement of magnetization (1.88 emu/g). A leaky type P–E hysteresis loop was observed for the pure one, whereas concave-like ferroelectric loops were obtained for Gd substituted samples. The possible origins of enhanced multiferroic properties have been explained on the basis of substituent, its concentration, phase purity, particle size, structural distortion and the modified magnetic structure. The measurement of magnetoelectric studies at room temperature revealed the coupling between magnetic and ferroelectric ordering, which is desirable for multifunctional device applications of multiferroics. - Highlights: • The substitution of Gd in BiFeO{sub 3} (BFO) nanoparticles led to structural distortion. • Average sizes of the substituted samples are less than the spin period of BFO. • Gd-substitution altered the original magnetic structure of BFO (AFM – FM). • M{sub r} of a substituted sample is an order of magnitude higher than that of BFO. • All the samples show magnetoelectric coupling

  17. γ-Fe{sub 2}O{sub 3} nanoparticles: An easily recoverable effective photo-catalyst for the degradation of rose bengal and methylene blue dyes in the waste-water treatment plant

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, Amit Kumar; Maji, Swarup Kumar; Adhikary, Bibhutosh, E-mail: bibhutoshadhikary@yahoo.in

    2014-01-01

    Graphical abstract: - Highlights: • γ-Fe{sub 2}O{sub 3} NPs from a single-source precursor and characterized by XRD, TEM, UV–vis spectra. • The NPs were tested as effective photocatalyst toward degradation of RB and MB dyes. • The possible pathway of the photocatalytic decomposition process has been discussed. • The active species, OH·, was detected by TA photoluminescence probing techniques. - Abstract: γ-Fe{sub 2}O{sub 3} nanoparticles (NPs) were synthesized from a single-source precursor complex [Fe{sub 3}O(C{sub 6}H{sub 5}COO){sub 6}(H{sub 2}O){sub 3}]NO{sub 3} by a simple thermal decomposition process and have been characterized by X-ray diffraction analysis (XRD), transmission electron microscopy (TEM) and UV–vis spectroscopic techniques. The NPs were highly pure and well crystallized having hexagonal morphology with an average particle size of 35 nm. The prepared γ-Fe{sub 2}O{sub 3} (maghemite) NPs show effective photo-catalytic activity toward the degradation of rose bengal (RB) and methylene blue (MB) dyes under visible light irradiation and can easily be recoverable in the presence of magnetic field for successive re-uses. The possible photo-catalytic decomposition mechanism is discussed through the detection of hydroxyl radical (OH·) by terephthalic acid photo-luminescence probing technique.

  18. Catalytic effect of monoclinic WO{sub 3}, hexagonal WO{sub 3} and H{sub 0.23}WO{sub 3} on the hydrogen sorption properties of Mg

    Energy Technology Data Exchange (ETDEWEB)

    Tonus, Florent; Bobet, Jean-Louis [CNRS, Universite de Bordeaux, ICMCB, 87 avenue du Dr. A. Schweitzer, Pessac F-33608 (France); Fuster, Valeria; Urretavizcaya, Guillermina; Castro, Facundo J. [Centro Atomico Bariloche (CNEA, CONICET), Instituto Balseiro (UNCUYO), Av. Bustillo 9500, San Carlos de Bariloche (Argentina)

    2009-05-15

    The H sorption properties of mixtures Mg + WO{sub 3} (having various structures) and Mg + H{sub 0.23}WO{sub 3} are reported. First, the higher conversion of Mg into MgH{sub 2} during reactive mechanical grinding (under 1.1 MPa of H{sub 2}) for higher WO{sub 3} content is due to the improvement of the milling efficiency. Then, it is shown that the hydrogen absorption properties are almost independent of the crystal structure of the catalyst and that only the particles' size and the specific surface play a major role. Finally, for the desorption process, it appears that the chemical composition and structure of the catalyst, together with the particle size and specific surface have an effect. (author)

  19. Propane combustion over Pt/Al{sub 2}O{sub 3} catalysts with different crystalline structures of alumina

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jung Eun; Kim, Bo Bae; Park, Eun Duck [Ajou University, Suwon (Korea, Republic of)

    2015-11-15

    The effects of the crystalline phases (α-Al{sub 2}O{sub 3}, κ-Al{sub 2}O{sub 3}, δ-Al{sub 2}O{sub 3}, θ-Al{sub 2}O{sub 3}, η-Al{sub 2}O{sub 3}, and γ-Al{sub 2}O{sub 3}) of the alumina support of Pt/Al{sub 2}O{sub 3} catalysts on the catalyst activity toward propane combustion were examined. The catalysts were characterized by N{sub 2} physisorption, CO chemisorption, temperature-programmed reduction (TPR), temperature programmed oxidation (TPO), transmission electron microscopy (TEM), and infrared spectroscopy (IR) after CO chemisorption. The Pt dispersion of the catalysts (surface Pt atoms/total Pt atoms), measured via CO chemisorption, was more dependent on the crystalline structure of alumina than on the surface area of alumina. The highest catalytic activity for propane combustion was achieved with Pt/α-Al{sub 2}O{sub 3}, which has the lowest Brunauer, Emmett, and Teller (BET) surface area and Pt dispersion. The lowest catalytic activity for propane combustion was exhibited by Pt/γ-Al{sub 2}O{sub 3}, which has the highest BET surface area and Pt dispersion. The catalytic activity was confirmed to increase with increasing Pt particle size in Pt/δ-Al{sub 2}O{sub 3}. The apparent activation energies for propane combustion over Pt/α-Al{sub 2}O{sub 3}, Pt/κ- Al{sub 2}O{sub 3}, Pt/δ-Al{sub 2}O{sub 3}, Pt/θ-Al{sub 2}O{sub 3}, Pt/η-Al{sub 2}O{sub 3}, and Pt/γ-Al{sub 2}O{sub 3} were determined to be 24.7, 21.4, 24.3, 22.1, 24.0, and 19.1 kcal/mol, respectively.

  20. Modeling and optimization of effective parameters on the size of synthesized Fe{sub 3}O{sub 4} superparamagnetic nanoparticles by coprecipitation technique using response surface methodology

    Energy Technology Data Exchange (ETDEWEB)

    Ghazanfari, Mohammad Reza, E-mail: Ghazanfari.mr@gmail.com [Department of Materials Science and Engineering, Ferdowsi University of Mashhad, 9177948974 Mashhad (Iran, Islamic Republic of); Kashefi, Mehrdad, E-mail: m-kashefi@um.ac.ir [Department of Materials Science and Engineering, Ferdowsi University of Mashhad, 9177948974 Mashhad (Iran, Islamic Republic of); Jaafari, Mahmoud Reza [Biotechnology Research Center, Nanotechnology Research Center, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad (Iran, Islamic Republic of)

    2016-05-01

    Generally, the statistical methods are defined as appropriate techniques to study the processes trends. In current research, the Fe{sub 3}O{sub 4} superparamagnetic nanoparticles were synthesized by coprecipitation method. In order to investigate the size properties of synthesized particles, the experimental design was done using central composite method (CCD) of response surface methodology (RSM) while the temperature, pH, and cation ratio of reaction were selected as influential factors. After particles synthesis based on designed runs, the different responses such as hydrodynamic size of particles (both freeze dried and air dried), size distribution, crystallite size, magnetic size, and zeta potential were evaluated by different techniques i.e. dynamic light scattering (DLS), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). Based on these results, the quadratic polynomial model was fitted for each response that could predict the response amounts. In following, the study of factors effects was carried out that showed the temperature, pH, and their interactions had higher effectiveness. Finally, by optimizing, it was clear that the minimum amounts of particle size (10.15 nm) and size distribution (13.01 nm) were reached in the minimum temperature (70 °C) and cation ratio (0.5) amounts and maximum pH amount (10.5). Moreover, the characterizations showed the particles size was about 10 nm while the amounts of M{sub s}, H{sub c}, and M{sub r} were equal to 60 (emu/g), 0.2 (Oe) and 0.22 (emu/g), respectively. - Highlights: • The Fe{sub 3}O{sub 4} nanoparticles were successfully synthesized by coprecipitation method. • By RSM technique, some predicted models were presented for particles size. • Temperature, pH and their interactions had most effectiveness on the particles size. • The drying techniques can effect on the size properties.

  1. ZnO/Ag heterostructures embedded in Fe{sub 3}O{sub 4} nanoparticles for magnetically recoverable photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Chidambaram, Siva; Pari, Baraneedharan [Division of Nanoscience and Technology, Anna University-BIT Campus, Thiruchirappalli, 620024 (India); Kasi, Nehru [Department of Chemistry, Anna University-BIT Campus, Thiruchirappalli, 620024 (India); Muthusamy, Sivakumar, E-mail: muthusiva@gmail.com [Division of Nanoscience and Technology, Anna University-BIT Campus, Thiruchirappalli, 620024 (India); Department of Chemistry, Anna University-BIT Campus, Thiruchirappalli, 620024 (India)

    2016-04-25

    Hybrid nanostructures made up of plasmonic noble metals (PNMs) and ZnO hold great promise of enhancing photocatalytic dye degradation rates, due to the remarkable abilities of PNMs like concentration of energetic photons, scattering of photons and exhibition of surface plasmon resonance (SPR). In order to effectively reuse the ZnO/Ag heterostructures for several catalytic reactions, we have coupled with Fe{sub 3}O{sub 4} nanoparticles (NPs). Respective indications from the structural and morphological analysis are the phase purity and particle nature of the composite materials. Fe{sub 3}O{sub 4}/ZnO/Ag nanocomposite has showed the saturation magnetization (M{sub s}) of 57.2 emu g{sup −1}. Characteristic SPR peak of Ag NPs at 450 nm along with the band edge absorption of ZnO at ∼370 nm are observed in the nanocomposite from the absorption graphs. Schottky contact occurrence between ZnO and Ag NPs is realized from the shift in the SPR peak position and also from the quenching of emission intensity of Fe{sub 3}O{sub 4}/ZnO composite for Ag incorporation. For illumination of visible photons, SPR of Ag NPs forms the energy electrons in the Fermi level of metal particles (E{sub fm}) then they fall into the Fermi level of ZnO (E{sub fs}) and are further trapped by the Fe{sup 3+} ions. This serious of electron separation process greatly enhance the methylene blue (MB) degradation rate. This electron transmigration is consistent at the interfaces of ternary nanocomposite, which aids the consistent degradation rate for several reaction cycles. Spine of the reaction behind the excellent photocatalytic reaction, (i.e.) electron transfer mechanism, is well illustrated and discussed in detail. - Highlights: • ZnO/Ag heterostructures are coupled to the Fe{sub 3}O{sub 4} nanoparticles to reuse the plasmonic photocatalysis. • Series electron trapping from Ag to ZnO particles and then to Fe{sup 3+} ions are occurring. • Rate of catalytic process of the composite is

  2. EUV blank defect and particle inspection with high throughput immersion AFM with 1nm 3D resolution

    NARCIS (Netherlands)

    Es, M.H. van; Sadeghian Marnani, H.

    2016-01-01

    Inspection of EUV mask substrates and blanks is demanding. We envision this is a good target application for massively parallel Atomic Force Microscopy (AFM). We envision to do a full surface characterization of EUV masks with AFM enabling 1nm true 3D resolution over the entire surface. The limiting

  3. Fabrication and characterization of a novel hydrophobic CaCO{sub 3} grafted by hydroxylated poly(vinyl chloride) chains

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Lixia [State Key Laboratory of Polymer Materials Engineering, Sichuan University (China); School of Chemical Science and Technology, Yunnan University (China); Yang, Simei; Luo, Xin [School of Chemical Science and Technology, Yunnan University (China); Lei, Jingxin [State Key Laboratory of Polymer Materials Engineering, Sichuan University (China); Cao, Qiue [School of Chemical Science and Technology, Yunnan University (China); Wang, Jiliang, E-mail: jlwang@ynu.edu.cn [School of Chemical Science and Technology, Yunnan University (China)

    2015-12-01

    Highlights: • Hydroxylated poly(vinyl chloride) (PVC-OH) with different molecular weight and hydroxyl value was successfully prepared by the suspension copolymerization. • PVC-OH was grafted onto the surface of CaCO{sub 3} particles by the urethane formation reaction. • The modified CaCO{sub 3} particles show excellent hydrophobicity. - Abstract: The hydroxylated PVC (PVC-OH) was successfully synthesized by a suspension polymerization of vinyl chloride (VC), butyl acrylate (BA) and hydroxyethyl acrylate (HEA). Novel hydrophobic CaCO{sub 3} was then prepared by a urethane formation reaction between methylene diphenyl diisocyanate (MDI) and the −OH groups both in the PVC-OH chains and on the surface of pristine CaCO{sub 3} particles. The effect of the PVC-OH content on the grafting ratio of treated CaCO{sub 3} particles was extensively investigated. Combining the result of Fourier transform infrared (FTIR) with that of water contact angle, it can be concluded that the hydrophobicity of CaCO{sub 3} had been efficiently improved by the PVC-OH segments grafted on the surface of CaCO{sub 3} particles. X-ray diffraction (XRD), thermal gravity analysis (TGA), scanning electron microscope (SEM) and transmission electron microscope (TEM) were also used to study crystalline behaviors, thermal stability and surface morphology of the modified CaCO{sub 3} particles, respectively. The change of specific surface area implying surface modification was investigated as well.

  4. Synthesis and structural characterization of Li{sub 3}Y(BO{sub 3}){sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Braeuchle, Sebastian; Huppertz, Hubert [Innsbruck Univ. (Austria). Inst. fuer Allgemeine, Anorganische und Theoretische Chemie

    2017-03-01

    Li{sub 3}Y(BO{sub 3}){sub 2} was prepared by high-temperature solid state synthesis at 900 C in a platinum crucible from lithium carbonate, boric acid, and yttrium(III) oxide. The compound crystallizes monoclinically in the space group P2{sub 1}/c (no. 14) (Z=4) isotypically to Li{sub 3}Gd(BO{sub 3}){sub 2}. The structure was refined from single-crystal X-ray diffraction data: a=8.616(3), b=6.416(3), c=10.014(2) Aa, β=116.6(2) , V=494.9(3) Aa{sup 3}, R1=0.0211, and wR2=0.0378 for all data. The crystal structure of Li{sub 3}Y(BO{sub 3}){sub 2} consists of [Y{sub 2}O{sub 14}] dinuclear units, which are interconnected to each other by planar B(1)O{sub 3} groups and LiO{sub 4} tetrahedra via common edges and corners along the a axis.

  5. Analysis of Individual Carbonaceous Particles Emitted from the Las Conchas Wildfire, Los Alamos, NM, in June-July 2011

    Science.gov (United States)

    Mazzoleni, C.; China, S.; Gorkowski, K.; Flowers, B. A.; Aiken, A. C.; Dubey, M. K.

    2012-12-01

    Carbonaceous aerosol emitted from biomass burning contributes significantly to atmospheric aerosol loadings regionally and globally. The net direct radiative forcing of biomass burning aerosol can be positive and/or negative and this depends on its composition, morphology and mixing state. Biomass burning aerosols can also change the cloud properties as they can act as cloud condensation nuclei. In this study we investigated biomass burning particles emitted from the Las Conchas wildfire in northern New Mexico that started on June 26, 2011 and burned an area of 245 square miles. Aerosol samples were collected on nucleopore filters at the Los Alamos National Laboratory during the third week of the wildfire event. Individual particles (~4000) were investigated using field-emission scanning electron microscopy and energy dispersive X-ray spectroscopy (EDS) to distinguish different carbonaceous particles and their shape, size, elemental composition and mixing state. A thermo-denuder was used to remove compounds that are volatile at temperatures up to 200 C, leaving behind the black carbon and any compounds that did not volatize completely. Smoke particles consisted of a) tar balls, which are amorphous spherical carbonaceous organic aerosols; b) organic particles with inorganic inclusions, c) soot particles and (d) soot with various inclusions. Two distinct kinds of tar balls, "electronically" dark and bright, were found using the field-emission scanning electron microscopy and were characterized for ambient and denuded conditions to understand coating effects and aging. It was found that dark tar balls are generally larger in size than the bright ones. Additionally, the difference between the size of ambient-bright and the size of denuded-bright tar balls was larger than the difference between the size of ambient-dark and the size of denuded-dark tar balls. EDS analysis showed that 70% of the dark tar balls had higher (~60%) relative oxygen content than in the bright

  6. Synthesis and physical properties of Cr–P-based intermetallic compounds: Cr{sub 3}P, Cr{sub 3}PC, and Cr{sub 3}PN

    Energy Technology Data Exchange (ETDEWEB)

    Zu, L.; Lin, S. [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Tong, P., E-mail: tongpeng@issp.ac.cn [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Lin, J.C.; Kan, X.C.; Wang, B.S.; Song, W.H. [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Sun, Y.P., E-mail: ypsun@issp.ac.cn [High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031 (China); Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China); Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China)

    2015-05-05

    Highlights: • Polycrystalline samples of Cr{sub 3}P, Cr{sub 3}PC, and Cr{sub 3}PN are first synthesized by using solid state reaction method. • A good quality of our samples is verified by the Rietveld refinement and electrical transport measurements. • We present a comprehensive understanding of physical properties of Cr{sub 3}P, Cr{sub 3}PC, and Cr{sub 3}PN. - Abstract: We report the synthesis, crystal structures and electrical/thermal transport properties of polycrystalline Cr{sub 3}PX (X = C, N, and vacancy) compounds. As a result, Cr{sub 3}PC and Cr{sub 3}PN have an orthorhombic crystal structure with space group Cmcm, while Cr{sub 3}P shows a tetragonal structure with space group I−4. All samples show good metallic behavior between 2 and 350 K in the measurement of electrical transport. At the same time, the Fermi-liquid behavior is observed at low temperatures for Cr{sub 3}PC (N) (2–50 K) and Cr{sub 3}P (2–22 K). Based on the fitting results of low-temperature resistivity and specific heat, large Kadowaki–Woods ratio of Cr{sub 3}PC (N) and Cr{sub 3}P were obtained, suggesting a considerably strong electron–electron correlation for all our samples. By analyzing the thermal conductivity data, it is found that the electron thermal conductivity is predominantly stronger than the phonon one at low temperatures for Cr{sub 3}P. As to Cr{sub 3}PC and Cr{sub 3}PN, however, both contributions are comparable in the whole temperature range investigated. Besides, phonon-drag effect was observed in the Seebeck coefficient α(T) curves for all the samples, which may explain the crossover of sign at 70 K in α(T) of Cr{sub 3}PN.

  7. Synthesis and characterization of TiO{sub 2}/Fe{sub 2}O{sub 3} core-shell nanocomposition film and their photoelectrochemical property

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Hui [State Key Laboratory of Superhard Materials, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Fu Wuyou, E-mail: fuwy56@163.com [State Key Laboratory of Superhard Materials, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Yang Haibin; Xu Yang; Zhao Wenyan; Zhang Yanyan; Chen Hui; Jing Qiang; Qi Xuefeng; Cao Jing; Zhou Xiaoming; Li Yixing [State Key Laboratory of Superhard Materials, Jilin University, 2699 Qianjin Street, Changchun 130012 (China)

    2011-08-15

    TiO{sub 2}/Fe{sub 2}O{sub 3} core-shell nanocomposition film has been fabricated via two-step method. TiO{sub 2} nanorod arrays are synthesized by a facile hydrothermal method, and followed by Fe{sub 2}O{sub 3} nanoparticles deposited on TiO{sub 2} nanorod arrays through an ordinary chemical bath deposition. The phase structures, morphologies, particle size, chemical compositions of the composites have been characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and ultraviolet-visible (UV-vis) spectrophotometer. The results confirm that Fe{sub 2}O{sub 3} nanoparticles of mean size ca. 10 nm coated on the surface of TiO2 NRs. After depositing Fe{sub 2}O{sub 3}, UV-vis absorption property is induces the shift to the visible-light range, the annealing temperature of 600 {sup o}C is the best condition for UV-vis absorption property of TiO{sub 2}/Fe{sub 2}O{sub 3} nanocomposite film, and increasing Fe content, optical activity are enhanced one by one. The photoelectrochemical (PEC) performances of the as-prepared composite nanorods are determined by measuring the photo-generated currents under illumination of UV-vis light. The TiO{sub 2} NRs modified by Fe{sub 2}O{sub 3} show the photocurrent value of 1.36 mA/cm{sup 2} at 0 V vs Ag/AgCl, which is higher than those of unmodified TiO{sub 2} NRs.

  8. CTAB-assisted ultrasonic synthesis, characterization and photocatalytic properties of WO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Sánchez-Martínez, D., E-mail: dansanm@gmail.com; Gomez-Solis, C.; Torres-Martinez, Leticia M.

    2015-01-15

    Highlights: • WO{sub 3} 2D nanostructures were synthesized by ultrasound method assisted with CTAB. • WO{sub 3} morphology was mainly of rectangular nanoplates with a thickness of ∼50 nm. • The highest surface area value of WO{sub 3} was obtained to lowest concentration of CTAB. • WO{sub 3} activity was attributed to morphology, surface area and the addition of CTAB. • WO{sub 3} nanoplates were able to causing almost complete mineralization of rhB and IC. - Abstract: WO{sub 3} 2D nanostructures have been prepared by ultrasound synthesis method assisted with CTAB using different molar ratios. The formation of monoclinic crystal structure of WO{sub 3} was confirmed by X-ray powder diffraction (XRD). The characterization of the WO{sub 3} samples was complemented by analysis of scanning electron microscopy (SEM), which revealed morphology mainly of rectangular nanoplates with a thickness of around 50 nm and length of 100–500 nm. Infrared spectroscopy (FT-IR) was used to confirm the elimination of the CTAB in the synthesized samples. The specific surface area was determinate by the BET method and by means of diffuse reflectance spectroscopy (DRS) it was determinate the band-gap energy (E{sub g}) of the WO{sub 3} samples. The photocatalytic activity of the WO{sub 3} oxide was evaluated in the degradation reactions of rhodamine B (rhB) and indigo carmine (IC) under Xenon lamp irradiation. The highest photocatalytic activity was observed in the samples containing low concentration of CTAB with morphology of rectangular nanoplates and with higher surface area value than commercial WO{sub 3}. Photodegradation of rhB and IC were followed by means of UV–vis absorption spectra. The mineralization degree of organic dyes by WO{sub 3} photocatalyst was determined by total organic carbon analysis (TOC) reaching percentages of mineralization of 92% for rhB and 50% for IC after 96 h of lamp irradiation.

  9. Measurement of fast minority /sub 3/He/sup + +/ energy distribution during ICRF heating

    Science.gov (United States)

    Post, D.E. Jr.; Grisham, L.R.; Medley, S.S.

    A method and means for measuring the fast /sub 3/He/sup + +/ distribution during /sub 3/He/sup + +/ minority Ion Cyclotron Resonance Frequency (ICRF) heating is disclosed. The present invention involves the use of 10 to 100 keV beams of neutral helium atoms to neutralize the fast /sub 3/He/sup + +/ ions in a heated plasma by double charge exchange (/sub 3/He/sup + +/ + /sub 4/He/sup 0/ ..-->.. /sub 3/He/sup 0/ + /sub 4/He/sup + +/). The neutralized fast /sub 3/He/sup 0/ atoms then escape from the hot plasma confined by a magnetic field and are detected by conventional neutral particle analyzing means. This technique permits the effectiveness of the coupling of the ion cyclotron waves to the /sub 3/He/sup + +/ minority ions to be accurately measured. The present invention is particularly adapted for use in evaluating the effectiveness of the intermediate coupling between the RF heating and the /sub 3/He/sup + +/ in an energetic toroidal plasma.

  10. New antiperovskite superconductor ZnNNi{sub 3}, and related compounds CdNNi{sub 3} and InNNi{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Uehara, Masatomo, E-mail: uehara@ynu.ac.j [Department of Physics, Faculty of Engineering, Yokohama National University, Hodogaya-ku Yokohama 240-8501 (Japan); Uehara, Akira; Kozawa, Katsuya; Yamazaki, Takahiro; Kimishima, Yoshihide [Department of Physics, Faculty of Engineering, Yokohama National University, Hodogaya-ku Yokohama 240-8501 (Japan)

    2010-12-15

    We briefly report the synthesis, electrical resistivity, magnetic susceptibility, and specific heat for a new antiperovskite superconductor ZnNNi{sub 3} with T{sub c} {approx} 3 K, and related compounds CdNNi{sub 3} and InNNi{sub 3}. In these materials, CdNNi{sub 3} has been synthesized for the first time by our work. The crystal structures of these compounds have the same antiperovskite-type such as MgCNi{sub 3} and CdCNi{sub 3}.

  11. Ni{sub 3}Al technology transfer

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K.; Viswanathan, S.; Santella, M.L. [Oak Ridge National Lab., TN (United States)] [and others

    1997-04-01

    Ductile Ni{sub 3}Al and Ni{sub 3}Al-based alloys have been identified for a range of applications. These applications require the use of material in a variety of product forms such as sheet, plate, bar, wire, tubing, piping, and castings. Although significant progress has been made in the melting, casting, and near-net-shape forming of nickel aluminides, some issues still remain. These include the need for: (1) high-strength castable composition for many applications that have been identified; (2) castability (mold type, fluidity, hot-shortness, porosity, etc.); (3) weld reparability of castings; and (4) workability of cast or powder metallurgy product to sheet, bar, and wire. The four issues listed above can be {open_quotes}show stoppers{close_quotes} for the commercial application of nickel aluminides. This report describes the work completed to address some of these issues during FY 1996.

  12. α-Fe{sub 2}O{sub 3} lithium battery anodes by nanocasting strategy from ordered 2D and 3D templates

    Energy Technology Data Exchange (ETDEWEB)

    Di Lupo, F. [GAME Lab, Department of Applied Science and Technology – DISAT, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Turin (Italy); Gerbaldi, C., E-mail: claudio.gerbaldi@polito.it [GAME Lab, Department of Applied Science and Technology – DISAT, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Turin (Italy); Casino, S.; Francia, C.; Meligrana, G. [GAME Lab, Department of Applied Science and Technology – DISAT, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Turin (Italy); Tuel, A. [Institut de Recherches sur la Catalyse, IRC-CNRS (UPR 5401), 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex (France); Penazzi, N. [GAME Lab, Department of Applied Science and Technology – DISAT, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Turin (Italy)

    2014-12-05

    Highlights: • Nanosized α-Fe{sub 2}O{sub 3} lithium battery conversion anodes with tunable morphology. • Nanocasting technique using MCM-41 and MCM-48 silica moulds is adopted. • Textural/morphological characteristics define the electrochemical behaviour. • α-Fe{sub 2}O{sub 3} replica of MCM-41 exhibits stable capacity (∼300 mA h g{sup −1}) after 100 cycles. • α-Fe{sub 2}O{sub 3} replica of MCM-41 shows promising prospects as high-capacity Li-ion battery anode. - Abstract: Nanocasting strategy is here proposed as effective approach to tune structure and size of α-Fe{sub 2}O{sub 3} active nanoparticles as a promising anode material for Li-ion cells. MCM-41 and MCM-48 silicas, presenting hexagonal 2D and cubic 3D symmetry, respectively, and regular pore diameter of about 4 nm are selected as moulds. The structural–morphological and electrochemical characteristics are assessed by X-ray diffraction, transmission electron microscopy, N{sub 2} physisorption at 77 K, cyclic voltammetry and galvanostatic discharge/charge cycling. It is here demonstrated that structural–morphological features change accordingly to the template used and careful control of the texture/particle characteristics is likely a fundamental variable noticeably affecting the cycling behaviour.

  13. Characterization of the insulator barrier and the superconducting transition temperature in GdBa{sub 2}Cu{sub 3}O{sub 7−δ}/BaTiO{sub 3} bilayers for application in tunnel junctions

    Energy Technology Data Exchange (ETDEWEB)

    Navarro, H., E-mail: henrynavarro@cab.cnea.gov.ar; Sirena, M.; Haberkorn, N. [Instituto Balseiro, Universidad Nacional de Cuyo and CNEA, 8400 Bariloche (Argentina); Centro Atómico Bariloche, Comisión Nacional de Energía Atómica. Av. Bustillo 9500, 8400 San Carlos de Bariloche (Argentina); Yang, Ilkyu [Department of Physics, Pohang University of Science and Technology, Pohang (Korea, Republic of); Kim, Jeehoon [Department of Physics, Pohang University of Science and Technology, Pohang (Korea, Republic of); CALDES, Institute for Basic Science, Pohang (Korea, Republic of)

    2015-07-28

    The optimization of the superconducting properties in a bottom electrode and the quality of an insulator barrier are the first steps in the development of superconductor/insulator/superconductor tunnel junctions. Here, we study the quality of a BaTiO{sub 3} tunnel barrier deposited on a 16 nm thick GdBa{sub 2}Cu{sub 3}O{sub 7−δ} thin film by using conductive atomic force microscopy. We find that the tunnel current is systematically reduced (for equal applied voltage) by increasing the BaTiO{sub 3} barrier thickness between 1.6 and 4 nm. The BaTiO{sub 3} layers present an energy barrier of ≈1.2 eV and an attenuation length of 0.35–0.5 nm (depending on the applied voltage). The GdBa{sub 2}Cu{sub 3}O{sub 7−δ} electrode is totally covered by a BaTiO{sub 3} thickness above 3 nm. The presence of ferroelectricity was verified by piezoresponse force microscopy for a 4 nm thick BaTiO{sub 3} top layer. The superconducting transition temperature of the bilayers is systematically suppressed by increasing the BaTiO{sub 3} thickness. This fact can be associated with stress at the interface and a reduction of the orthorhombicity of the GdBa{sub 2}Cu{sub 3}O{sub 7−δ}. The reduction in the orthorhombicity is expected by considering the interface mismatch and it can also be affected by reduced oxygen stoichiometry (poor oxygen diffusion across the BaTiO{sub 3} barrier)

  14. Fe{sub 2}O{sub 3}-Poly-pyrrole hybrid nano-composite materials for super-capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Mallouki, M.; Tran-Van, F.; Sarrazin, C.; Chevrot, C. [Cergy-Pontoise Univ., Lab. de Physicochimie des Polymeres et des Interfaces (LPPI), EA 2528 95 (France); Fauvarque, J.F. [CNAM, Lab. d' Electrochimie Industrielle, 75 - Paris (France); Simon, P. [Universite Paul Sabatier, CIRIMAT-LCMIE, UMR 5085, 31 - Toulouse (France); De, A. [Saha Institute of Nuclear Physics, Calcutta (India)

    2004-07-01

    Fe{sub 2}O{sub 3}-Poly-pyrrole hybrid nano-composite materials chemically synthesized from colloid particles of iron oxide in aqueous solution have been processed to realize electrode materials for super-capacitor applications. The performances have been evaluated by cyclic voltammetry and galvano-static techniques in a three-electrode cell. The capacitance of Fe{sub 2}O{sub 3}-PPy hybrid nano-composite doped with para-toluene-sulfonate reaches 47 mAh/g in PC/NEt{sub 4}BF{sub 4} with a good stability during cycling (loss of 3% after 1000 cycles). Transmission Electronic Microscopy indicates a porous nano-structure with spherical particles in a range of 400-500 nm which ensures a good accessibility of the electrolyte in the bulk of the electro-active hybrid material. Preliminary studies with room temperature ionic liquid show promising results since the specific capacitance reaches 427 F/g in 1- ethyl-3-methyl-imidazolium bis((tri-fluoro-methyl)sulfonyl)amide (EMITFSI). (authors)

  15. Quasi-homoepitaxial growth of a-axis oriented PrBa sub 2 Cu sub 3 O sub 7 sub - subdelta thick film on (100) YBa sub 2 Cu sub 3 O sub 7 sub - subdelta single crystal

    CERN Document Server

    Sato, M; Morishita, T

    2003-01-01

    The structural characterizations of the quasi-homoepitaxial growth of a-axis oriented PrBa sub 2 Cu sub 3 O sub 7 sub - subdelta thick film grown on (100) YBa sub 2 Cu sub 3 O sub 7 sub - subdelta single crystal were investigated in comparison with those of the film grown on (001) YBa sub 2 Cu sub 3 O sub 7 sub - subdelta single crystal. The a-axis oriented PrBa sub 2 Cu sub 3 O sub 7 sub - subdelta films, expected to be a barrier layer, were prepared using a dc-95 MHz hybrid plasma sputtering on (100) and (001) YBa sub 2 Cu sub 3 O sub 7 sub - subdelta single crystals that are superconducting ground planes. The atomic force microscopy image revealed that the surfaces of 700-nm-thick a-axis PrBa sub 2 Cu sub 3 O sub 7 sub - subdelta films on (100) YBa sub 2 Cu sub 3 O sub 7 sub - subdelta single crystals were smooth with a mean roughness of 2.8 nm. X-ray diffraction scans showed that a-axis PrBa sub 2 Cu sub 3 O sub 7 sub - subdelta films deposited on (100) YBa sub 2 Cu sub 3 O sub 7 sub - subdelta single cry...

  16. Surfactant-assisted preparation of core-shell-type TiO{sub 2}–Fe{sub 2}O{sub 3} composites and their photocatalytic activities under room light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Inseok; You, Kyoung-Eun; Kim, Young Chai; Oh, Seong-Geun, E-mail: seongoh@hanyang.ac.kr

    2014-10-15

    Graphical abstract: - Highlights: • TiO{sub 2}–Fe{sub 2}O{sub 3} composites having core-shell structure were synthesized in cationic surfactant solution. • Thickness of Fe{sub 2}O{sub 3} shell was controlled by varying the concentration Fe salt. • Composites exhibited high performance of MB photodegradation under room light irradiation. • Higher catalytic activities were attributed to band edge shift and decrease of recombination. - Abstract: TiO{sub 2}–Fe{sub 2}O{sub 3} composites of core-shell structure were synthesized by using surfactant-assisted preparation method. The shell on TiO{sub 2} surface was composed of small Fe{sub 2}O{sub 3} nanoparticles with an average diameter of 12 nm. The thickness of Fe{sub 2}O{sub 3} shell was controlled by varying the concentration of Fe salt and using CTAB as the surfactant and binder. After annealing at 450 °C, the crystal structures of composites were found to be anatase and hematite mixed phase. Composites showed the ferromagnetic property which is favorable in water treatment. The characteristics of composites were analyzed by using TEM, EDS, XRD, XPS, VSM and PL. As an application of TiO{sub 2}–Fe{sub 2}O{sub 3} composites in water treatment, their catalytic performances for the degradation of methylene blue (MB) were examined by using UV–Vis spectrophotometer under room light irradiation. TiO{sub 2}–Fe{sub 2}O{sub 3} composites prepared with CTAB exhibited high performance of MB photodegradation because of the effects of band edge shift and decrease of recombination attributed to the formation of Fe{sub 2}O{sub 3} particles on TiO{sub 2} surface.

  17. Prediction of novel hard phases of Si{sub 3}N{sub 4}: First-principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Lin; Hu, Meng; Wang, Qianqian; Xu, Bo; Yu, Dongli; Liu, Zhongyuan; He, Julong, E-mail: hjl@ysu.edu.cn

    2015-08-15

    Exploration of novel hard metastable phases of silicon nitride was performed using a recently developed particle-swarm optimization method within the CALYPSO software package. Three potential hard metastable phases of t-Si{sub 3}N{sub 4}, m-Si{sub 3}N{sub 4}, and o-Si{sub 3}N{sub 4} were predicted. These phases are mechanically and dynamically stable at ambient pressure based on their elastic constants and phonon dispersions. t-Si{sub 3}N{sub 4} and m-Si{sub 3}N{sub 4} exhibit lower energies than γ-Si{sub 3}N{sub 4} at pressures below 2.5 GPa and 2.9 GPa, respectively, which promise that the formers could be obtained by quenching from γ-Si{sub 3}N{sub 4}. o-Si{sub 3}N{sub 4} is a better high-pressure metastable phase than CaTi{sub 2}O{sub 4}-type Si{sub 3}N{sub 4} proposed by Tatsumi et al. and it can come from the transition of γ-Si{sub 3}N{sub 4} under 198 GPa. The theoretical band gaps of t-Si{sub 3}N{sub 4}, m-Si{sub 3}N{sub 4}, and o-Si{sub 3}N{sub 4} at ambient pressure were 3.15 eV, 3.90 eV, and 3.36 eV, respectively. At ambient pressure, the Vickers hardness values of t-Si{sub 3}N{sub 4} (32.6 GPa), m-Si{sub 3}N{sub 4} (31.5 GPa), and o-Si{sub 3}N{sub 4} (36.1 GPa) are comparable to β-Si{sub 3}N{sub 4} and γ-Si{sub 3}N{sub 4}. With the pressure increasing, t-Si{sub 3}N{sub 4}, m-Si{sub 3}N{sub 4}, and o-Si{sub 3}N{sub 4} will change from the brittle to ductile state at about 15.7 GPa, 7.3 GPa and 28.9 GPa, respectively. - Graphical abstract: This figure shows the crystal structures of three Si{sub 3}N{sub 4} predicted in this manuscript, and left to right: t-Si{sub 3}N{sub 4}, m-Si{sub 3}N{sub 4} and o-Si{sub 3}N{sub 4}. - Highlights: • We explored three metastable phases of Si{sub 3}N{sub 4} — t-Si{sub 3}N{sub 4}, m-Si{sub 3}N{sub 4}, and o-Si{sub 3}N{sub 4}. • The enthalpies of t and m- are much lower than that of γ at ambient pressure. • ois one further high pressure phase than γ. • o-Si{sub 3}N{sub 4} is the most hardest phase in Si{sub

  18. Spontaneous and stimulated emission in Sm{sup 3+}-doped YAl{sub 3}(BO{sub 3}){sub 4} single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Ryba-Romanowski, Witold [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław (Poland); Lisiecki, Radosław, E-mail: R.Lisiecki@int.pan.wroc.pl [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wrocław (Poland); Beregi, Elena [Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, Budapest (Hungary); Martín, I.R. [Departamento de Física, Instituto de Materiales y Nanotecnología (IMN), Universidad de La Laguna, 38206 S/C de Tenerife, Laguna (Spain)

    2015-11-15

    Single crystals of YAl{sub 3}(BO{sub 3}){sub 4} doped with trivalent samarium were grown by the top-seeded high temperature solution method and their absorption and emission spectra were investigated. Optical pumping into prominent absorption band around 405 nm feeds the {sup 4}G{sub 5/2} metastable level giving rise to intense visible luminescence distributed in several spectral lines with the most intense line around 600 nm characterized by a branching ratio of 0.42 and peak emission cross section of 0.25×10{sup −20} cm{sup 2}. Optical amplification at 600 nm with a gain coefficient of 2.9 cm{sup −1} was achieved during a pump-and-probe experiment. - Highlights: • YAB:Sm crystal grown by the top-seeded high temperature solution method. • Spectroscopic qualities relevant for visible laser operation. • YAB:Sm single crystal used in a pump-and-probe experiment. • Optical amplification properties of samarium doped YAl{sub 3}(BO{sub 3}){sub 4}.

  19. Single-crystalline CuGeO{sub 3} nanorods: Synthesis, characterization and properties

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Fangfang [College of Chemistry, Northeast Normal University, Changchun 130024 (China); Xing, Yan, E-mail: xingy202@nenu.edu.cn [College of Chemistry, Northeast Normal University, Changchun 130024 (China); Su, Zhongmin [College of Chemistry, Northeast Normal University, Changchun 130024 (China); Song, Shuyan [State Key Laboratory of Rare Earth Resource Utilizations, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

    2013-07-15

    Graphical abstract: - Highlights: • Single crystalline CuGeO{sub 3} nanorods were prepared via a hydrothermal route. • The material exhibits greatly enhanced activity in photocatalytic degradation of dyes. • The magnetic susceptibility measurements indicate spin-Peierls transition properties. • CuGeO{sub 3} nanorods may be of potential application in future integrated optical devices. - Abstract: Single crystalline CuGeO{sub 3} nanorods with a diameter of 20–35 nm and a length up to 1 μm have been prepared via a facile hydrothermal route with the assistance of ethylenediamine. Some influencing factors such as the reaction time, reaction temperature, the volume of ethylenediamine were revealed to play crucial roles in the formation of the CuGeO{sub 3} nanorods. A possible growth mechanism was proposed based on the experimental results. Significantly, this is the first time that CuGeO{sub 3} was used as a photocatalyst for organic pollutant degradation under UV light irradiation. The reaction constant (k) of CuGeO{sub 3} nanorods was five times that of the sample prepared by solid-state reaction under UV light irradiation. Additionally, the optical and magnetic properties of CuGeO{sub 3} nanorods were systematically studied.

  20. Investigation of magnetic properties of Fe{sub 3}O{sub 4} nanoparticles using temperature dependent magnetic hyperthermia in ferrofluids

    Energy Technology Data Exchange (ETDEWEB)

    Nemala, H.; Thakur, J. S.; Lawes, G.; Naik, R., E-mail: rnaik@wayne.edu [Department of Physics and Astronomy, Wayne State University, Detroit, Michigan 48202 (United States); Naik, V. M. [Department of Natural Sciences, University of Michigan-Dearborn, Dearborn, Michigan 48128 (United States); Vaishnava, P. P. [Department of Physics, Kettering University, Flint, Michigan 48504 (United States)

    2014-07-21

    Rate of heat generated by magnetic nanoparticles in a ferrofluid is affected by their magnetic properties, temperature, and viscosity of the carrier liquid. We have investigated temperature dependent magnetic hyperthermia in ferrofluids, consisting of dextran coated superparamagnetic Fe{sub 3}O{sub 4} nanoparticles, subjected to external magnetic fields of various frequencies (188–375 kHz) and amplitudes (140–235 Oe). Transmission electron microscopy measurements show that the nanoparticles are polydispersed with a mean diameter of 13.8 ± 3.1 nm. The fitting of experimental dc magnetization data to a standard Langevin function incorporating particle size distribution yields a mean diameter of 10.6 ± 1.2 nm, and a reduced saturation magnetization (∼65 emu/g) compared to the bulk value of Fe{sub 3}O{sub 4} (∼95 emu/g). This is due to the presence of a finite surface layer (∼1 nm thickness) of non-aligned spins surrounding the ferromagnetically aligned Fe{sub 3}O{sub 4} core. We found the specific absorption rate, measured as power absorbed per gram of iron oxide nanoparticles, decreases monotonically with increasing temperature for all values of magnetic field and frequency. Using the size distribution of magnetic nanoparticles estimated from the magnetization measurements, we have fitted the specific absorption rate versus temperature data using a linear response theory and relaxation dissipation mechanisms to determine the value of magnetic anisotropy constant (28 ± 2 kJ/m{sup 3}) of Fe{sub 3}O{sub 4} nanoparticles.

  1. Surface-related properties of gamma-Fe sub 2 O sub 3 nanoparticles

    CERN Document Server

    Tronc, E; Cherkaoui, R; Chaneac, C; Nogues, M; Kachkachi, H; Fiorani, D; Testa, A M; Greneche, J M; Jolivet, J P

    2000-01-01

    Surface/interface effects on static magnetic properties of gamma-Fe sub 2 O sub 3 nanoparticles of average diameter 3-10 nm, have been investigated by magnetisation measurements (0-55 kOe, 4.2-300 K) as a function of the field and temperature and by in-field (60 kOe) Moessbauer spectroscopy experiments. The comparison of the results between particle dispersions with different concentrations in polyvinylic alcohol and phosphate-coated particles provides evidence for the interplay between surface anisotropy, intraparticle exchange coupling between surface and core, and interparticle interactions. Enhanced local surface anisotropy and surface spin disorder at low temperature have been found in both systems. In the dispersions, the existence of a canted surface spin structure below approx 85 K is evidenced by in-field Moessbauer experiments and by magnetisation measurements showing a strong increase of the high-field magnetisation with decreasing temperature as the field increases, more and more important with de...

  2. Surface areas of turbostratic graphitic carbons prepared from a resin using nickel particles, 20 nm, as graphitization catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Oya, A.; Inoue, E.; Otani, S.; Marsh, H.

    1981-11-01

    Nickel particles were used to graphitize catalytically a non-graphitizing carbon to create a turbostratic graphitic material called the T/SUB/s-component. This method was examined by X-ray diffraction. Coals on heat treatment to temperatures >1270 K form T/SUB/s-component carbons. Therefore, considerations of the properties of the T/SUB/s-component carbon may have relevance to considerations of the operational performances of blast furnace coke. (22 refs.)

  3. NHS-MAS{sub 3}: a bifunctional chelator alternative to NHS-MAG{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Chang, F.; Qu, T.; Rusckowski, M.; Hnatowich, D.J

    1999-04-01

    This laboratory uses an N-hydroxysuccinimide derivative of S-acetylmercaptoacetyltriglycine (NHS-MAG{sub 3}) to conjugate amines for subsequent labeling with {sup 99m}Tc. However, the synthesis from triglycerine is general and not restricted to this tripeptide. We had earlier selected a small number of alternative tripeptides and synthesized the corresponding NHS derivatives. Each was then evaluated in a search for bifunctional chelators with properties superior to NHS-MAG{sub 3}, such as lower serum protein binding or improved stability to cysteine challenge. Based on these preliminary results, NHS-S-acetylmercaptoacetyltriserine (NHS-MAS{sub 3}) was selected for further investigation. We have now conjugated this bifunctional chelator to biocytin and to an amine-derivatized peptide nucleic acid (PNA). Both carriers were also conjugated with NHS-MAG{sub 3} under identical conditions and all were labeled with {sup 99m}Tc at neutral pH and at boiling temperature while the conjugated PNAs were radiolabelled at neutral pH and at room temperature. Regardless of the chelator, reverse phase HPLC radiochromatograms of the labeled biotins and PNAs after purification showed a single peak. However, by size exclusion HPLC, the radiochromatograms always showed several peaks even after purification, but the MAS{sub 3} radiochromatograms were less complicated. For biotin and PNA both, radiolabeling via MAS{sub 3} showed improved {sup 99m}Tc stability in 37 deg. C serum and in cysteine solution. The four preparations were administered to mice implanted in one thigh with avidin beads (biotins) or complementary PNA beads (PNAs). At 5 h post-administration, no significant differences were observed in the targeting of PNA beads between the two chelators, however the target thigh/normal thigh ratio was significantly higher for MAS{sub 3}-biotin compared to MAG{sub 3}-biotin. We conclude that labeling biocytin and amine-derivatized PNA with NHS-MAS{sub 3} compared to NHS-MAG{sub 3

  4. Iron oxide and iron carbide particles produced by the polyol method

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Y., E-mail: yyasu@rs.kagu.tus.ac.jp; Shimizu, R. [Tokyo University of Science, Department of Chemistry (Japan); Kobayashi, Y. [The University of Electro-Communications, Graduate School of Informatics and Engineering (Japan)

    2016-12-15

    Iron oxide (γ-Fe{sub 2}O{sub 3}) and iron carbide (Fe{sub 3}C) particles were produced by the polyol method. Ferrocene, which was employed as an iron source, was decomposed in a mixture of 1,2-hexadecandiol, oleylamine, and 1-octadecene. Particles were characterized using Mössbauer spectroscopy, X-ray diffraction, and transmission electron microscopy. It was found that oleylamine acted as a capping reagent, leading to uniform-sized (12-16 nm) particles consisting of γ-Fe {sub 2}O{sub 3}. On the other hand, 1-octadecene acted as a non-coordinating solvent and a carbon source, which led to particles consisting of Fe{sub 3}C and α-Fe with various sizes.

  5. Freeze drying synthesis of Li{sub 3}MnO{sub 4} cathode material for Li-ion batteries: A physico-electrochemical study

    Energy Technology Data Exchange (ETDEWEB)

    Surace, Yuri; Simões, Mário; Karvonen, Lassi; Yoon, Songhak; Pokrant, Simone [Laboratory Materials for Energy Conversion, EMPA – Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf (Switzerland); Weidenkaff, Anke, E-mail: weidenkaff@imw.uni-stuttgart.de [Materials Chemistry, Institute for Materials Science, University of Stuttgart, Heisenbergstrasse 3, DE-70569 Stuttgart (Germany)

    2015-09-25

    Highlights: • Facilitated synthesis of Li{sub 3}MnO{sub 4} with a smaller thermal budget via freeze drying. • Electrochemical activity enhanced by micro- and nanostructure modifications. • Capacity increase of 30% at 1st discharge versus standard synthesis process. - Abstract: Li{sub 3}MnO{sub 4}, a lithium rich phase containing manganese (V), is a promising cathode material for Li-ion batteries due to its very high theoretical capacity (698 A h kg{sup −1}). Li{sub 3}MnO{sub 4} was synthesized from freeze dried precursors at 398 K. Combined structural, morphological and chemical characterization by XRD, TGA, SEM, TEM and XPS revealed improvements in the micro- and nanostructure in comparison to the material synthesized by a standard solid state chemistry route. The average particle size decreased from 10 μm to 3.5 μm and the average crystallite size from close to 100 nm to around 30 nm. These modifications enhanced the capacity (23% at 10 A kg{sup −1} and up to 31% at 50 A kg{sup −1} with a maximum discharge capacity of 290 A h kg{sup −1}) and the rate capability.

  6. Preparation and drug-loading properties of Fe{sub 3}O{sub 4}/Poly(styrene-co-acrylic acid) magnetic polymer nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Wensheng [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Coordination Chemistry Institute, School of Chemistry and Chemical Engineering and Life Science, Chaohu University, Chaohu 238000 (China); Shen, Yuhua, E-mail: s_yuhua@163.com [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Xie, Anjian [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Zhang, Weiqiang [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Coordination Chemistry Institute, School of Chemistry and Chemical Engineering and Life Science, Chaohu University, Chaohu 238000 (China)

    2013-11-15

    Fe{sub 3}O{sub 4}/poly(styrene-co-acrylic acid) magnetic polymer nanocomposites were synthesized by the dispersion polymerization method using styrene as hard monomer, acrylic acid as functional monomer, Fe{sub 3}O{sub 4} nanoparticles modified with oleic acid as core, and poly(styrene-co-acrylic acid) as shell. Drug-loading properties of magnetic polymer nanocomposites with curcumin as a model drug were also studied. The results indicated that magnetic polymer nanocomposites with monodisperse were obtained, the particle size distribution was 50–120 nm, and the average size was about 100 nm. The contents of poly(styrene-co-acrylic acid) and Fe{sub 3}O{sub 4} nanoparticles in magnetic polymer nanocomposites were 74% and 24.7%, respectively. The drug-loading capacity and entrapment efficiency were 2.5% and 44.4%, respectively. The saturation magnetization of magnetic polymer nanocomposites at 300 K was 20.2 emu/g without coercivity and remanence. The as-prepared magnetic polymer nanocomposites have not only lots of functional carboxyl groups but also stronger magnetic response, which might have potential applications in drug carrier and targeted drug release.

  7. Orthorhombic MoO{sub 3} nanobelts based NO{sub 2} gas sensor

    Energy Technology Data Exchange (ETDEWEB)

    Mane, A.A. [Thin Film Nanomaterials Laboratory, Department of Physics, Shivaji University, Kolhapur 416 004 (India); General Science and Humanities Department, Sant Gajanan Maharaj College of Engineering, Mahagaon, 416 503 (India); Moholkar, A.V., E-mail: avmoholkar@gmail.com [Thin Film Nanomaterials Laboratory, Department of Physics, Shivaji University, Kolhapur 416 004 (India)

    2017-05-31

    Highlights: • The effect of thickness on physicochemical and NO{sub 2} gas sensing properties of sprayed MoO{sub 3} nanobelts has been reported. • The sprayed MoO{sub 3} nanobelts show the NO{sub 2} gas response of 68% for 100 ppm concentration at an operating temperature of 200 °C. • The lower detection limit of MoO{sub 3} nanobelts based NO{sub 2} sensor is found to be half of the IDLH value (20 ppm). - Abstract: Molybdenum trioxide (MoO{sub 3}) nanobelts have been deposited onto the glass substrates using chemical spray pyrolysis (CSP) deposition method. The XRD patterns reveal that films are polycrystalline having an orthorhombic crystal structure. Raman spectra confirm that the films are orthorhombic in phase. The XPS study shows the presence of two well resolved spectral lines of Mo-3d core levels appearing at the binding energy values of 232.82 eV and 235.95 eV corresponding to Mo-3d{sub 5/2} and Mo-3d{sub 3/2}, respectively. These binding energy values are assigned to Mo{sup 6+} oxidation state of fully oxidized MoO{sub 3}. The FE-SEM micrographs show the formation of nanobelts-like morphology. The AFM micrographs reveal that the RMS surface roughness increases from 16.5 nm to 17.5 nm with increase in film thickness from 470 nm to 612 nm and then decreases to 16 nm for 633 nm film thickness. The band gap energy is found to be decreased from 3.40 eV to 3.38 eV. To understand the electronic transport phenomenon in MoO{sub 3} thin films, dielectric properties are studied. For 612 nm film thickness, the highest NO{sub 2} gas response of 68% is obtained at an operating temperature of 200 °C for 100 ppm concentration with response and recovery times of 15 s and 150 s, respectively. The lower detection limit is found to be 10 ppm which is half of the immediately dangerous to life or health (IDLH) value of 20 ppm. Finally, NO{sub 2} gas sensing mechanism in an orthorhombic MoO{sub 3} crystal structure is discussed in detail.

  8. The effect of humic acid on the formation and solubility of secondary solid phases (Nd(OH)CO{sub 3} and Sm(OH)CO{sub 3})

    Energy Technology Data Exchange (ETDEWEB)

    Antoniou, S.; Pashalidis, I. [Cyprus Univ., Nicosia (Cyprus). Chemistry Dept.; Gessner, A.; Kumke, M.U. [Potsdam Univ., Potsdam-Golm (Germany). Chemistry Dept./Physical Chemistry

    2011-07-01

    The formation of secondary Ln(III) solid phases (e.g. Nd(OH)CO{sub 3} and Sm(OH)CO{sub 3}) has been studied as a function of the humic acid (HA) concentration in 0.1 M NaClO{sub 4} aqueous solution and their solubility has been investigated in the neutral pH range (6.5-8) under normal atmospheric conditions. Nd(III) and Sm(III) were selected as analogues for trivalent lanthanide and actinide ions. The solid phases under investigation have been prepared by alkaline precipitation and characterized by TGA, ATR-FTIR, XRD, TRLFS, DR-UV-Vis and Raman spectroscopy, and solubility measurements. The spectroscopic data obtained indicate that Nd(OH)CO{sub 3} and Sm(OH)CO{sub 3} are stable and remain the solubility limiting solid phases even in the presence of increased HA concentration (0.5 g/L) in solution. Upon base addition in the Ln(III)-HA system decomplexation of the previously formed Ln(III)-humate complexes and precipitation of two distinct phases occurs, the inorganic (Ln(OH)CO{sub 3}) and the organic phase (HA), which is adsorbed on the particle surface of the former. Nevertheless, HA affects the particle size of the solid phases. Increasing HA concentration results in decreasing crystallite size of the Nd(OH)CO{sub 3} and increasing crystallite size of the Sm(OH)CO{sub 3} solid phase, and affects inversely the solubility of the solid phases. However, this impact on the solid phase properties is expected to be of minor relevance regarding the chemical behavior and migration of trivalent lanthanides and actinides in the geosphere. (orig.)

  9. Microstructure and mechanical properties of sputter deposited Ni/Ni{sub 3}Al multilayer films at elevated temperature

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chao [Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai 200240 (China); Feng, Kai, E-mail: fengkai@sjtu.edu.cn [Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai 200240 (China); Li, Zhuguo, E-mail: lizg@sjtu.edu.cn [Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai 200240 (China); Lu, Fenggui; Huang, Jian; Wu, Yixiong [Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai 200240 (China)

    2016-08-15

    Highlights: • Ni/Ni{sub 3}Al multilayers are prepared by magnetron sputtering. • Both grain size and phase constitution of annealed Ni/Ni{sub 3}Al multilayers are dependent on individual layer thickness. • The hardness of annealed Ni/Ni{sub 3}Al multilayers varies with individual layer thickness and annealing temperature. • 40 nm Ni/Ni{sub 3}Al multilayer exhibits excellent hardness at elevated temperature. - Abstract: Nano-structured Ni/Ni{sub 3}Al multilayer was prepared by magnetron sputtering, with individual layer thicknesses h varying from 10 to 160 nm. The microstructure and hardness of Ni/Ni{sub 3}Al multilayer were investigated by X-ray diffraction, transmission electron microscopy and nanoindentation. The results show that the hardness increases with decreasing h for as-deposited and 500 °C annealed multilayers. When annealed at 700 °C, the hardness approach a peak value at h = 40 nm with followed by softening at smaller h. The influence of individual layer thickness, grain size as well as formation of ordered Ni{sub 3}Al on strengthening mechanisms of Ni/Ni{sub 3}Al multilayers at elevated temperature are discussed.

  10. γ-Fe{sub 2}O{sub 3} by sol–gel with large nanoparticles size for magnetic hyperthermia application

    Energy Technology Data Exchange (ETDEWEB)

    Lemine, O.M., E-mail: leminej@yahoo.com [Physics Department, College of Sciences, Al Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh (Saudi Arabia); Omri, K. [Laboratory of Physics of Materials and Nanomaterials Applied at Environment (LaPhyMNE), Faculty of Sciences in Gabes, Gabes (Tunisia); Iglesias, M.; Velasco, V. [Instituto de Magnetismo Aplicado, UCM-ADIF-CSIC (Spain); Crespo, P.; Presa, P. de la [Instituto de Magnetismo Aplicado, UCM-ADIF-CSIC (Spain); Dpto. Física de Materiales, Universidad Complutense de Madrid (Spain); El Mir, L. [Physics Department, College of Sciences, Al Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh (Saudi Arabia); Laboratory of Physics of Materials and Nanomaterials Applied at Environment (LaPhyMNE), Faculty of Sciences in Gabes, Gabes (Tunisia); Bouzid, Houcine [Promising Centre for Sensors and Electronic Devices (PCSED), Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Laboratoire des Matériaux Ferroélectriques, Faculté des Sciences de Sfax, Route Soukra Km 3 5, B.P. 802, F-3018 Sfax (Tunisia); Yousif, A. [Department of Physics, College of Science, Sultan Qaboos University, P.O. Box 36, Code 123, Al Khoud (Oman); Al-Hajry, Ali [Promising Centre for Sensors and Electronic Devices (PCSED), Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia)

    2014-09-01

    Highlights: • Iron oxides nanoparticles with different sizes are successfully synthesized using sol–gel method. • The obtained nanoparticles are mainly composed of maghemite phase (γ-Fe{sub 2}O{sub 3}). • A non-negligible coercive field suggests that the particles are ferromagnetic. • A mean heating efficiency of 30 W/g is obtained for the smallest particles at 110 kHz and 190 Oe. - Abstract: Iron oxides nanoparticles with different sizes are successfully synthesized using sol–gel method. X-ray diffraction (XRD) and Mössbauer spectroscopy show that the obtained nanoparticles are mainly composed of maghemite phase (γ-Fe{sub 2}O{sub 3}). XRD and transmission electron microscopy (TEM) results suggest that the nanoparticles have sizes ranging from 14 to 30 nm, which are indeed confirmed by large magnetic saturation and high blocking temperature. At room temperature, the observation of a non-negligible coercive field suggests that the particles are ferro/ferrimagnetic. The specific absorption rate (SAR) under an alternating magnetic field is investigated as a function of size, frequency and amplitude of the applied magnetic field. A mean heating efficiency of 30 W/g is obtained for the smallest particles at 110 kHz and 190 Oe, whereas further increase of particle size does not improve significantly the heating efficiency.

  11. Preparation, structure and photoluminescence of nanoscaled-Nd: Lu{sub 3}Al{sub 5}O{sub 12}

    Energy Technology Data Exchange (ETDEWEB)

    Ding Lihua [Anhui Provincial Key Lab of Optical Devices and Materials, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Zhang, Qingli, E-mail: zql@aiofm.ac.cn [Anhui Provincial Key Lab of Optical Devices and Materials, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Luo Jianqiao; Liu Wenpeng [Anhui Provincial Key Lab of Optical Devices and Materials, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Zhou Wenlong [Anhui Provincial Key Lab of Optical Devices and Materials, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Yin Shaotang [Anhui Provincial Key Lab of Optical Devices and Materials, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China)

    2011-10-20

    Highlights: > Nd:Lu{sub 3}Al{sub 5}O{sub 12} (Nd:LuAG) nano-crystalline was synthesized by co-precipitation method, its polycrystalline phase can be formed above 900 deg. C and its structure was refined by Rietveld method. > From the point of structure, studies on the difference of crystal field interaction between Nd:LuAG and Nd:YAG were carried out. > Compared with Nd:YAG, Nd:LuAG has broader absorption FWHM at 808 nm, longer fluorescence lifetime and larger emission cross section. - Abstract: Nd:Lu{sub 3}Al{sub 5}O{sub 12} (Nd:LuAG) nano-crystalline was synthesized by co-precipitation method. Its phase transformation, structure, absorption and photoluminescence properties were studied. The Nd:LuAG polycrystalline phase is formed above 900 deg. C and its particle sizes are in the range of 18-36 nm. The structure of Nd:LuAG was refined by Rietveld method. The lattice parameters and the distortion of Lu{sup 3+}-O{sup 2-} polyhedron in Nd:LuAG are larger than that of in pure LuAG. Because the distortion of Lu{sup 3+}-O{sup 2-} polyhedron is larger than that of Y{sup 3+}-O{sup 2-} polyhedron in YAG and the distance of Lu{sup 3+}-O{sup 2-} is smaller than that of Y{sup 3+}-O{sup 2-} in YAG, Nd{sup 3+} in LuAG experiences a stronger crystal field effect, which is proved by the crystal field strength and the chemical environment parameter. The absorption spectrum shows that Nd:LuAG has a broad absorption band at 808 nm with FWHM above 6 nm, which is favorable for improving laser efficiency. The fluorescence lifetime from {sup 4}F{sub 3/2} {yields} {sup 4}I{sub 11/2} transition is 320 {mu}s and longer than that of Nd:YAG. The longer lifetime is propitious to energy storage. The emission cross section at 1064 nm is 2.89 x 10{sup -19} cm{sup 2}, taking into account the Boltzmann distribution of the excited state. The emission cross section in Nd:LuAG is also larger than that of Nd:YAG, which is useful for laser operation. All results indicate that Nd:LuAG is a promising

  12. Microstructures and properties of CH{sub 3}NH{sub 3}PbI{sub 3−x}Cl{sub x} hybrid solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Kohei, E-mail: suzuki@mat.usp.ac.jp, E-mail: oku@mat.usp.ac.jp; Suzuki, Atsushi, E-mail: suzuki@mat.usp.ac.jp, E-mail: oku@mat.usp.ac.jp; Zushi, Masahito, E-mail: suzuki@mat.usp.ac.jp, E-mail: oku@mat.usp.ac.jp; Oku, Takeo, E-mail: suzuki@mat.usp.ac.jp, E-mail: oku@mat.usp.ac.jp [Department of Materials Science, The University of Shiga Prefecture 2500 Hassaka, Hikone, Shiga 522-8533 (Japan)

    2015-02-27

    Halide-perovskite CH{sub 3}NH{sub 3}PbI{sub 3} was produced on mesoporous TiO{sub 2} layer by spin-coating a precursor solution of PbCl{sub 2} and CH{sub 3}NH{sub 3}I in dimethylformamide. The role of the annealing process and chlorine (Cl) doping for the perovskite-phase formation was investigated. It was found that crystallization of the perovskite materials was stimulated by the annealing process, and that longer annealing time is necessary for the Cl-doped perovskite compared with that of non-doped perovskite phase.

  13. Microstructure and mechanical properties of carbon/carbon composites doped with LaCl{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Li Kezhi, E-mail: likezhi@nwpu.edu.cn [State Key Laboratory of Solidification Processing, Carbon/Carbon Composites Research Center, Northwestern Polytechnical University, Xi' an 710072 (China); Deng Hailiang; Li Hejun; Li Xin; Zhao Xueni; Luo Huijuan [State Key Laboratory of Solidification Processing, Carbon/Carbon Composites Research Center, Northwestern Polytechnical University, Xi' an 710072 (China)

    2011-11-25

    Highlights: {yields} Addition of LaCl{sub 3} decreased the densification duration of C/C composites. {yields} LaCl{sub 3} affected obviously the microstructure of intrabundle matrix. {yields} LaCl{sub 3} enhanced the toughness and strength of C/C composites. - Abstract: Carbon fiber felts with different LaCl{sub 3} contents were densified to produce carbon/carbon composites by film boiling chemical vapor infiltration from xylene pyrolysis at 1223 to 1323 K. Microstructure and mechanical properties of the composites were studied by polarized light microscopy, scanning electron microscopy, and three-point flexural test. Results showed that, the interbundle matrix of these composites was dominated by rough laminar (RL) pyrocarbon; whereas the intrabundle matrix may vary depended on the LaCl{sub 3} content. RL, smooth laminar (SL), and isotropic pyrocarbon were formed mainly when the LaCl{sub 3} content was 0, 5-10, and 15 wt%, respectively. The composites produced from the preforms with 5 and 10 wt% LaCl{sub 3} exhibited a pseudo-plastic fracture behavior combined with high flexural strength and toughness, which was attributed to the presence of lanthanum compound particles, the proper bonding of fiber-matrix interface, and the formation of SL pyrocarbon.

  14. Investigation on the preparation and luminescence emission of LaF{sub 3}:Eu{sup 3+}@LaF{sub 3}/SiO{sub 2} core-shell nanostructure

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Jun, E-mail: jun-shao@snnu.edu.cn; Wang, Zhaojin; Wang, Ruibo; Liu, Zhihui; Wang, Linxiao; Guo, Jingxia; Li, Xiaoyi; Zhang, Mingdi; Zhang, Chengyun; Zheng, Hairong, E-mail: hrzheng@snnu.edu.cn

    2017-05-15

    LaF{sub 3}:Eu{sup 3+}, LaF{sub 3}:Eu{sup 3+}@LaF{sub 3}, LaF{sub 3}:Eu{sup 3+}@CeF{sub 3} and LaF{sub 3}:Eu{sup 3+}@SiO{sub 2} nanoparticles were successfully synthesized via hydrothermal route and modified Stöber method. The surface property of LaF{sub 3}:Eu{sup 3+} particle was successfully modified by coating LaF{sub 3} and SiO{sub 2} shell onto the particle, which resulted in the change of the surface property and luminescence emission of LaF{sub 3}:Eu{sup 3+}. It was found that the surface quenchers were decreased and thus the nonradiative pathways were reduced with core/shell structure, which not only enhanced the yellow emission of the sample, but also changed the intensity ratio of the yellow to orange emission. The dependence of the shell property and shell thickness on the luminescence emission spectra were investigated systematically. The current investigation can provide useful information for developing applications in biological imaging, detection, and sensing and other aspects.

  15. Dielectric property of NiTiO{sub 3} doped substituted ortho-chloropolyaniline composites

    Energy Technology Data Exchange (ETDEWEB)

    Lakshmi, Mohana; Faisal, Muhammad [Department of Physics, PES Institute of Technology, BSC, Bangalore- 560100 (India); Roy, Aashish S. [Department of Materials Science, Gulbarga University, Gulbarga-585106, Karnataka (India); Khasim, Syed, E-mail: syed.pes@gmail.com [Department of Physics, PES Institute of Technology, BSC, Bangalore- 560100 (India); Department of Physics, University of Tabuk-71491 (Saudi Arabia); Sajjan, K. C. [Department of Physics, Veerashaiva College, Bellary - 583 104, Karnataka (India); Revanasiddappa, M. [Department of Chemistry, PES Institute of Technology, BSC, Bangalore - 560100 (India)

    2013-11-15

    Ortho-chloropolyaniline (OCP)-NiTiO{sub 3} composites have been synthesized via in-situ polymerization of ortho-chloroaniline with various weight percentages of NiTiO{sub 3.} Fourier Transform Infrared spectroscopic studies of Ortho-chloropolyaniline and its composites indicated the formation of composites as a result of Vander Waal's interaction between OCP and NiTiO{sub 3} particles. Surface morphology of OCP and OCP-NiTiO{sub 3} composites were studied using Scanning Electron Microscope (SEM). The SEM micrographs indicated a modified morphology after the composite formation. Dielectric properties and electric modulus of OCP and OCP-NiTiO{sub 3} composites have been investigated in the frequency range of 50 Hz – 5 MHz. It has been noticed that electrical resistance decreases with increase in weight percentage of NiTiO{sub 3} particles in polymer matrix as well as with applied frequency. The display of semicircular arcs in Cole-Cole plots indicates the formation of series resistor and capacitor in network causing a decrease in the relaxation time and as a result conductivity enhances in these composites. The facile and cost effective synthesis process and excellent dielectric and conductivity response of these materials makes them promising materials for practical applications.

  16. Spectra of surface plasmon polariton enhanced electroluminescence from electroformed Al-Al{sub 2}O{sub 3}-Ag diodes

    Energy Technology Data Exchange (ETDEWEB)

    Hickmott, T. W. [Department of Physics, State University of New York at Albany, Albany, New York 12222 (United States)

    2015-03-07

    Narrow band-pass filters have been used to measure the spectral distribution of electroluminescent photons with energies between 1.8 eV and 3.0 eV from electroformed Al-Al{sub 2}O{sub 3}-Ag diodes with anodic Al{sub 2}O{sub 3} thicknesses between 12 nm and 18 nm. Electroforming of metal-insulator-metal (MIM) diodes is a non-destructive dielectric breakdown that results in a conducting channel in the insulator and changes the initial high resistance of the MIM diode to a low resistance state. It is a critical step in the development of resistive-switching memories that utilize MIM diodes as the active element. Electroforming of Al-Al{sub 2}O{sub 3}-Ag diodes in vacuum results in voltage-controlled negative resistance (VCNR) in the current-voltage (I-V) characteristics. Electroluminescence (EL) and electron emission into vacuum (EM) develop simultaneously with the current increase that results in VCNR in the I-V characteristics. EL is due to recombination of electrons injected at the Al-Al{sub 2}O{sub 3} interface with radiative defect centers in Al{sub 2}O{sub 3}. Measurements of EL photons between 1.8 eV and 3.0 eV using a wide band-pass filter showed that EL intensity is exponentially dependent on Al{sub 2}O{sub 3} thickness for Al-Al{sub 2}O{sub 3}-Ag diodes between 12 nm and 20 nm thick. Enhanced El intensity in the thinnest diodes is attributed to an increase in the spontaneous emission rate of recombination centers due to high electromagnetic fields generated in Al{sub 2}O{sub 3} when EL photons interact with electrons in Ag or Al to form surface plasmon polaritons at the Al{sub 2}O{sub 3}-Ag or Al{sub 2}O{sub 3}-Al interface. El intensity is a maximum at 2.0–2.2 eV for Al-Al{sub 2}O{sub 3}-Ag diodes with Al{sub 2}O{sub 3} thicknesses between 12 nm and 18 nm. EL in diodes with 12 nm or 14 nm of Al{sub 2}O{sub 3} is enhanced by factors of 8–10 over EL from a diode with 18 nm of Al{sub 2}O{sub 3}. The extent of EL enhancement in

  17. Friction stir processing of an aluminum-magnesium alloy with pre-placing elemental titanium powder: In-situ formation of an Al{sub 3}Ti-reinforced nanocomposite and materials characterization

    Energy Technology Data Exchange (ETDEWEB)

    Khodabakhshi, F., E-mail: farzadkhodabakhshi83@gmail.com [Department of Materials Science and Engineering, School of Engineering, Shiraz University, Zand Boulevard, Shiraz (Iran, Islamic Republic of); Simchi, A. [Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, 14588 Tehran (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, 14588 Tehran (Iran, Islamic Republic of); Kokabi, A.H. [Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, 14588 Tehran (Iran, Islamic Republic of); Gerlich, A.P. [Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, ON (Canada)

    2015-10-15

    A fine-grained Al–Mg/Al{sub 3}Ti nanocomposite was fabricated by friction stir processing (FSP) of an aluminum-magnesium (AA5052) alloy with pre-placed titanium powder in the stirred zone. Microstructural evolutions and formation of intermetallic phases were analyzed by optical and electron microscopic techniques across the thickness section of the processed sheets. The microstructure of the nanocomposite consisted of a fine-grained aluminum matrix (1.5 µm), un-reacted titanium particles (<40 µm) and reinforcement particles of Al{sub 3}Ti (<100 nm) and Mg{sub 2}Si (<100 nm). Detailed microstructural analysis indicated solid-state interfacial reactions between the aluminum matrix and micro-sized titanium particles to form Al{sub 3}Ti intermetallic phase. The hard inclusions were then fractured and re-distributed in the metal matrix by the severe thermo-mechanical conditions imposed by FSP. Evaluation of mechanical properties by hardness measurement and uniaxial tensile test determined significant enhancement in the mechanical strength (by 2.5 order of magnetite) with a high ductility (~22%). Based on a dislocation-based model analysis, it was suggested that the strength enhancement was governed by grain refinement and the presence of hard inclusions (4 vol%) in the metal matrix. Fractographic studies also showed a ductile-brittle fracture mode for the nanocomposite compared with fully ductile rupture of the annealed alloy as well as the FSPed specimen without pre-placing titanium particles. - Highlights: • FSP was employed to fabricate in situ nanocomposite. • The AA5052 Al alloy with pre-placed micro-sized Ti particles were utilized. • The structural analysis was revealed that the in situ formation of Al{sub 3}Ti nanophase. • The SZ grain structure was refined by PSN and ZHP mechanisms during DRX. • Hardness and tensile strength were improved up to ~2.5 times with a good ductility.

  18. Epitaxial growth of Fe{sub 3}Si/CaF{sub 2}/Fe{sub 3}Si magnetic tunnel junction structures on CaF{sub 2}/Si(111) by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Ken' ichi [Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); Suemasu, Takashi [Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan)], E-mail: suemasu@bk.tsukuba.ac.jp; Kuwano, Noriyuki; Hara, Daisuke [Department of Applied Science for Electronics and Materials, Kyushu University, 6-1 Kasuga, Fukuoka 816-8580 (Japan); Akinaga, Hiroyuki [Nanoelectronics Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568 (Japan)

    2007-08-15

    The Fe{sub 3}Si(24 nm)/CaF{sub 2}(2 nm)/Fe{sub 3}Si(12 nm) magnetic tunnel junction (MTJ) structures were grown epitaxially on CaF{sub 2}/Si(111) by molecular beam epitaxy (MBE). The 12-nm-thick Fe{sub 3}Si underlayer was grown epitaxially on CaF{sub 2/}Si(111) at approximately 400 deg. C; however, the surface of the Fe{sub 3}Si film was very rough, and thus a lot of pinholes are considered to exist in the 2-nm-thick CaF{sub 2} barrier layer. The average roughness (Ra) of the CaF{sub 2} barrier layer was 7.8 nm. This problem was overcome by low-temperature deposition of Fe and Si at 80 deg. C on CaF{sub 2}/Si(111), followed by annealing at 250 deg. C for 30 min to form the Fe{sub 3}Si layer. The Ra roughness was significantly reduced down to approximately 0.26 nm. A hysteresis loop with coercive field H{sub c} of approximately 25 Oe was obtained in the magnetic field dependence of Kerr rotation at room temperature (RT)

  19. Synthesis, crystal structure, and properties of Bi{sub 3}TeBO{sub 9} or Bi{sub 3}(TeO{sub 6})(BO{sub 3}): a non-centrosymmetric borate-tellurate(VI) of bismuth

    Energy Technology Data Exchange (ETDEWEB)

    Daub, Michael; Krummer, Michael; Hoffmann, Anke [Institut fuer Anorganische und Analytische Chemie, Albert-Ludwigs-Universitaet, Albertstrasse 21, 79104, Freiburg (Germany); Bayarjargal, Lkhamsuren [Institut fuer Geowissenschaften, Abt. Kristallographie, Goethe-Universitaet, Altenhoeferallee 1, 60438, Frankfurt am Main (Germany); Hillebrecht, Harald [Institut fuer Anorganische und Analytische Chemie, Albert-Ludwigs-Universitaet, Albertstrasse 21, 79104, Freiburg (Germany); Freiburger Materialforschungszentrum FMF, Albert-Ludwigs-Universitaet, Stefan-Meier-Strasse 25, 79104, Freiburg (Germany)

    2017-01-26

    Pale-yellow single crystals of the new borate tellurate(VI) Bi{sub 3}TeBO{sub 9} were obtained by reaction of stoichiometric amounts of Bi{sub 2}O{sub 3}, B{sub 2}O{sub 3}, and Te(OH){sub 6} at 780 C. The non-centrosymmetric crystal structure (P6{sub 3}, Z=2, a=8.7454(16), c=5.8911(11) Aa, 738 refl., 43 param, R1=0.037, wR2=0.093) contains isolated trigonal-planar BO{sub 3} units and nearly undistorted TeO{sub 6} octahedra. The Bi{sup 3+} cations are located in between in octahedral voids. The BiO{sub 6} octahedra are significantly distorted to a [3+3] pattern (2.25/2.50 Aa) due to the ns{sup 2} configuration. According to the structural features, the formula can be written as Bi{sub 3}(TeO{sub 6})(BO{sub 3}). Alternatively, the structure can also be described as hcp of oxygen with Te{sup VI} and Bi{sup III} in octahedral voids and B{sup III} in trigonal- planar voids. The vibrational spectra show the typical features of BO{sub 3} and TeO{sub 6} units with a significant {sup 10}B/{sup 11}B isotopic splitting of the IR-active B-O valence mode (1248 and 1282 cm{sup -1}). The UV/Vis spectrum shows an optical band edge with an onset around 480 nm (2.6 eV). MAS-NMR spectra of {sup 11}B show an anisotropic signal with a quadrupole coupling constant of C{sub Q}=2.55 MHz. and a very small deviation from rotational symmetry (η=0.2). The isotropic chemical shift is 20.1 ppm. The second harmonic generation (SHG) test was positive with an activity comparable to potassium dihydrogen phosphate (KDP). Bi{sub 3}TeBO{sub 9} decomposes in air at 825 C to Bi{sub 2}TeO{sub 5}. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Preparation of ultra-thin and high-quality WO{sub 3} compact layers and comparision of WO{sub 3} and TiO{sub 2} compact layer thickness in planar perovskite solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jincheng; Shi, Chengwu, E-mail: shicw506@foxmail.com; Chen, Junjun; Wang, Yanqing; Li, Mingqian

    2016-06-15

    In this paper, the ultra-thin and high-quality WO{sub 3} compact layers were successfully prepared by spin-coating-pyrolysis method using the tungsten isopropoxide solution in isopropanol. The influence of WO{sub 3} and TiO{sub 2} compact layer thickness on the photovoltaic performance of planar perovskite solar cells was systematically compared, and the interface charge transfer and recombination in planar perovskite solar cells with TiO{sub 2} compact layer was analyzed by electrochemical impedance spectroscopy. The results revealed that the optimum thickness of WO{sub 3} and TiO{sub 2} compact layer was 15 nm and 60 nm. The planar perovskite solar cell with 15 nm WO{sub 3} compact layer gave a 9.69% average and 10.14% maximum photoelectric conversion efficiency, whereas the planar perovskite solar cell with 60 nm TiO{sub 2} compact layer achieved a 11.79% average and 12.64% maximum photoelectric conversion efficiency. - Graphical abstract: The planar perovskite solar cell with 15 nm WO{sub 3} compact layer gave a 9.69% average and 10.14% maximum photoelectric conversion efficiency, whereas the planar perovskite solar cell with 60 nm TiO{sub 2} compact layer achieved a 11.79% average and 12.64% maximum photoelectric conversion efficiency. Display Omitted - Highlights: • Preparation of ultra-thin and high-quality WO{sub 3} compact layers. • Perovskite solar cell with 15 nm-thick WO{sub 3} compact layer achieved PCE of 10.14%. • Perovskite solar cell with 60 nm-thick TiO{sub 2} compact layer achieved PCE of 12.64%.

  1. A contribution to the kinetic study of the metatectic reaction U+U{sub 3}Si{sub 2}{yields}U{sub 3}Si; Contribucion al Estudio cinetico de la Reaccion Metatectica U+U{sub 3}Si{sub 2} U{sub 3}Si

    Energy Technology Data Exchange (ETDEWEB)

    Arroyo Ruiperez, J.; Esteban Hernandez, J. A.

    1962-07-01

    An experimental study has been made to decide upon the advantages and drawbacks of the different methods and reagents employed in the metallography of U-Si alloys. It has been observed that all samples thermally treated to form the epsilon-phase undergo from the beginning a coalescence of the U{sub 3}Si{sub 2} particles, which makes practically useless any fine state of dispersion that might be present originally, as recommended by some authors. The coalescence of the U{sub 3}Si{sub 2} particle decreases the surface available for reaction and consequently the reaction rate. (Author) 7 refs.

  2. YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} matrix-induced in situ growth of plasmonic Au nanoparticles for biological sensor devices

    Energy Technology Data Exchange (ETDEWEB)

    Katzer, C., E-mail: christian.katzer@uni-jena.de; Grosse, V.; Schmidl, F.; Michalowski, P. [Friedrich-Schiller-Universitaet Jena, Institut fuer Festkoerperphysik (Germany); Schmidl, G.; Mueller, R.; Dellith, J.; Schmidt, C.; Jatschka, J.; Fritzsche, W. [Institute of Photonic Technology (IPHT) (Germany)

    2012-12-15

    The authors present a novel method of fabricating crystalline gold nanoparticles used in plasmonic application. The preparation and characterization of monocrystalline Au nanoparticles with diameters between 10 and 100 nm embedded in an YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} matrix is presented as well as a future vision of structured particle arrangements by photolithographic procedures. To use these particles for biological applications, the matrix may has to be dissolved to obtain extracted nanoparticles on a dielectric substrate. Whether the nanoparticles change their position during the extraction process is investigated and the realized dissolving procedure by citric acid solution is shown. The dissolution of the matrix thereby is investigated by X-ray diffraction experiments and energy-dispersive X-ray spectroscopy. Furthermore, the spectral characterization by particle selection is illustrated based on microspectroscopy.

  3. Light induced suppression of Kondo effect at amorphous LaAlO{sub 3}/SrTiO{sub 3} interface

    Energy Technology Data Exchange (ETDEWEB)

    Liu, G. Z.; Qiu, J.; Jiang, Y. C.; Zhao, R.; Yao, J. L.; Zhao, M.; Gao, J., E-mail: jugao@hku.hk [Research Center for Solid State Physics and Materials, School of Mathematics and Physics, Suzhou University of Science and Technology, Suzhou 215009 (China); Feng, Y. [Department of Electrical and Computer Engineering, The University of Alabama, Tuscaloosa, Alabama 35487 (United States)

    2016-07-18

    We report photoelectric properties of two-dimensional electron gas (2DEG) at an amorphous LaAlO{sub 3}/SrTiO{sub 3} interface. Under visible light illumination (650 nm), an enhancement of electric conductivity is observed over the temperature range from 2 to 300 K. Particularly, a resistance upturn appearing below 25 K, which is further proved to from the Kondo effect, is suppressed by the 650 nm visible light. From the results of light-assisted Hall measurements, light irradiation increases the carrier mobility rather than carrier density in the Kondo regime. It is suggested that light induces the decoherence effect of localized spin states, hence the electron scattering is weakened and the carrier mobility is improved accordingly. Moreover, the enhancement of electrical conductivity by visible light verifies that in-gap states located in the SrTiO{sub 3} side of the interface play an important role in the electrical transport of the amorphous SrTiO{sub 3}-based oxide 2DEG system. Our results provide deeper insight into the photoinduced effects in the 2DEG system, paving the way for the design of optoelectronic devices based on oxides.

  4. Crystal structure change of Li{sub 2+x}TiO{sub 3+y} tritium breeder under moist air

    Energy Technology Data Exchange (ETDEWEB)

    Hara, Masanori, E-mail: masahara@ctg.u-toyama.ac.j [Hydrogen Isotope Research Center, University of Toyama, Gofuku 3190, Toyama 930-8555 (Japan); Togashi, Yuka; Matsuyama, Masao [Hydrogen Isotope Research Center, University of Toyama, Gofuku 3190, Toyama 930-8555 (Japan); Oya, Yasuhisa; Okuno, Kenji [Radioscience Research Laboratory, Faculty of Science, Shizuoka University, Ohya 836, Suruga-ku Shizuoka 422-8529 (Japan)

    2010-09-30

    To investigate the aging behavior of Li{sub 2+x}TiO{sub 3+y}, the materials Li{sub 2.0}TiO{sub 3+y}, Li{sub 2.2}TiO{sub 3+y} and Li{sub 2.4}TiO{sub 3+y} were stored under moist air at ambient temperature. Under these conditions the weight of Li{sub 2.0}TiO{sub 3+y} increased by only 1% in 100 days, which provides evidence for the high chemical stability of Li{sub 2}TiO{sub 3}. In comparison, under the same storage conditions the weights of Li{sub 2.2}TiO{sub 3+y} and Li{sub 2.4}TiO{sub 3+y} increased by 14% and 18%, respectively. The observed weight gain is attributed to the uptake of water, and to the reaction of a by-product of Li{sub 2+x}TiO{sub 3+y} with water and carbon dioxide. The weight gain curves were evaluated by the Jander equation. From the analysis, it was possible to obtain the diffusion coefficient of water through Li{sub 2}TiO{sub 3} particles at ambient temperature. The determined value was 2 x 10{sup -17} m{sup 2}/s.

  5. Densification and texture evolution of Bi{sub 4}Ti{sub 3}O{sub 12} templated Na{sub 0.5}Bi{sub 0.5}TiO{sub 3}-BaTiO{sub 3} ceramics: Effects of excess Bi{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Su Shi [Institute of Electro Ceramics and Devices, School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Zuo Ruzhong, E-mail: piezolab@hfut.edu.cn [Institute of Electro Ceramics and Devices, School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Lv Danya [Institute of Electro Ceramics and Devices, School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China)

    2012-04-05

    Highlights: Black-Right-Pointing-Pointer Excess Bi{sub 2}O{sub 3} induces anomalous microstructure in BIT templated NBT-BT ceramics. Black-Right-Pointing-Pointer Undoped samples have a high degree grain orientation compared to Bi{sub 2}O{sub 3} doped ones. Black-Right-Pointing-Pointer The mechanism of texture development in Bi{sub 2}O{sub 3} liquid phase was put forward. - Abstract: 0.94Na{sub 0.5}Bi{sub 0.5}TiO{sub 3}-0.06BaTiO{sub 3} lead-free ceramics were fabricated by templated grain growth method using 5 vol% platelet Bi{sub 4}Ti{sub 3}O{sub 12} (BIT) templates. The effect of the addition of excess Bi{sub 2}O{sub 3} on the densification and the texture evolution was investigated. A high degree of grain orientation (f {approx} 0.93) and an excellent piezoelectric coefficient d{sub 33} of {approx}290 pC/N were obtained for undoped samples, however the texture was hardly developed for Bi{sub 2}O{sub 3} doped samples whose densification behavior yet could be significantly improved. It was found that the Bi{sub 2}O{sub 3} liquid phase can promote the particle rearrangement and mass transport, but simultaneously change the surface morphology of BIT templates and matrix grains from an atomically rough to smooth structure. The Ostwald growth was thus induced dominantly in the diametrical direction and little in the thickness direction of plate-like templates. The results provided a good reference for selecting the sintering aid in the fabrication of textured ceramics.

  6. Oxidant effect of La(NO{sub 3}){sub 3}·6H{sub 2}O solution on the crystalline characteristics of nanocrystalline ZrO{sub 2} films grown by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Nam Khen [Graduate School of Energy Science and Technology, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134 (Korea, Republic of); Vacuum Center, Korea Research Institute of Standards and Science (KRISS), 267 Gajeong-ro, Yuseong-gu, Daejeon 34113 (Korea, Republic of); Kim, Jin-Tae [Vacuum Center, Korea Research Institute of Standards and Science (KRISS), 267 Gajeong-ro, Yuseong-gu, Daejeon 34113 (Korea, Republic of); Department of Nanomaterials Science and Engineering, University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon 34113 (Korea, Republic of); Kang, Goru; An, Jong-Ki; Nam, Minwoo [Vacuum Center, Korea Research Institute of Standards and Science (KRISS), 267 Gajeong-ro, Yuseong-gu, Daejeon 34113 (Korea, Republic of); Kim, So Yeon [Graduate School of Energy Science and Technology, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134 (Korea, Republic of); Park, In-Sung, E-mail: parkis77@hanyang.ac.kr [Institute of Nano Science and Technology, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763 (Korea, Republic of); Yun, Ju-Young, E-mail: jyun@kriss.re.kr [Vacuum Center, Korea Research Institute of Standards and Science (KRISS), 267 Gajeong-ro, Yuseong-gu, Daejeon 34113 (Korea, Republic of); Department of Nanomaterials Science and Engineering, University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon 34113 (Korea, Republic of)

    2017-02-01

    Highlights: • The La(NO{sub 3}){sub 3}·6H{sub 2}O aqua solution is introduced as an oxidant in ALD process. • The H{sub 2}O and La(NO{sub 3}){sub 3}·6H{sub 2}O lead different crystalline properties of ZrO{sub 2} films. • Concentration of La(NO{sub 3}){sub 3}·6H{sub 2}O solution minimally influences crystalline status. - Abstract: Nanocrystalline ZrO{sub 2} films were synthesized by atomic layer deposition method using CpZr[N(CH{sub 3}){sub 2}]{sub 3} (Cp = C{sub 5}H{sub 5}) as the metal precursor and La(NO{sub 3}){sub 3}·6H{sub 2}O solution as the oxygen source. La element in the deposited ZrO{sub 2} films could not be detected as its content was below the resolution limit of the X-ray photoelectron spectroscopy. The alternative introduction of La(NO{sub 3}){sub 3}·6H{sub 2}O solution to conventionally used H{sub 2}O as the oxidant effectively altered the crystalline structure, grain size, and surface roughness of the grown ZrO{sub 2} films. Specifically, the crystalline structure of the ZrO{sub 2} film changed from a mixture of tetragonal and monoclinic phases to monoclinic phase. The average grain size also increased, and the resulting film surface became rougher. The average grain sizes of the ZrO{sub 2} films prepared from La(NO{sub 3}){sub 3}·6H{sub 2}O solution at concentrations of 10, 20, 30, and 40% were 280, 256, 208, and 200 nm, respectively, whereas that prepared using H{sub 2}O oxidant was 142 nm. However, the concentration of La(NO{sub 3}){sub 3}·6H{sub 2}O solution minimally influenced the crystalline characteristics of the nanocrystalline ZrO{sub 2} films i.e., the crystalline structure, grain size, and surface roughness except for crystallite size.

  7. Development of ODS-Fe{sub 3}Al alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wright, I.G.; Pint, B.A.; Tortorelli, P.F.; McKamey, C.G. [Oak Ridge National Lab., TN (United States)

    1997-12-01

    The overall goal of this program is to develop an oxide dispersion-strengthened (ODS) version of Fe{sub 3}Al that has sufficient creep strength and resistance to oxidation at temperatures in the range 1000 to 1200 C to be suitable for application as heat exchanger tubing in advanced power generation cycles. The main areas being addressed are: (a) alloy processing to achieve the desired alloy grain size and shape, and (b) optimization of the oxidation behavior to provide increased service life compared to semi-commercial ODS-FeCrAl alloys intended for the same applications. The recent studies have focused on mechanically-alloyed powder from a commercial alloy vendor. These starting alloy powders were very clean in terms of oxygen content compared to ORNL-produced powders, but contained similar levels of carbon picked up during the milling process. The specific environment used in milling the powder appears to exert a considerable influence on the post-consolidation recrystallization behavior of the alloy. A milling environment which produced powder particles having a high surface carbon content resulted in a consolidated alloy which readily recrystallized, whereas powder with a low surface carbon level after milling resulted in no recrystallization even at 1380 C. A feature of these alloys was the appearance of voids or porosity after the recrystallization anneal, as had been found with ORNL-produced alloys. Adjustment of the recrystallization parameters did not reveal any range of conditions where recrystallization could be accomplished without the formation of voids. Initial creep tests of specimens of the recrystallized alloys indicated a significant increase in creep strength compared to cast or wrought Fe{sub 3}Al, but the specimens failed prematurely by a mechanism that involved brittle fracture of one of the two grains in the test cross section, followed by ductile fracture of the remaining grain. The reasons for this behavior are not yet understood. The

  8. Comparison of structural and luminescence properties of Dy{sub 2}O{sub 3} nanopowders synthesized by co-precipitation and green combustion routes

    Energy Technology Data Exchange (ETDEWEB)

    Chandrasekhar, M. [Prof. C.N.R. Rao Centre for Advanced Materials, Tumkur University, Tumkur 572 103 (India); Department of Physics, Acharya Institute of Technology, Bangalore 560 107 (India); Nagabhushana, H., E-mail: bhushanvlc@gmail.com [Prof. C.N.R. Rao Centre for Advanced Materials, Tumkur University, Tumkur 572 103 (India); Sudheerkumar, K.H. [Department of Chemistry, B.M.S. Institute of Technology, Bangalore 560 064 (India); Dhananjaya, N. [Department of Physics, B.M.S. Institute of Technology, Bangalore 560 064 (India); Sharma, S.C. [Vice chancellor, Chhattisgarh Swamy Vivekananda Technical University, North Park Avenue, Sector – 8, Bhilai, Chhattisgarh 490 009 (India); Kavyashree, D. [Department of Physics, Channabasaveshwara Institute of Technology, Gubbi 572 216 (India); Shivakumara, C. [Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560 012 (India); Nagabhushana, B.M. [Department of Chemistry, M.S. Ramaiah Institute of Technology, Bangalore 560 054 (India)

    2014-07-01

    Highlights: • Dy{sub 2}O{sub 3} nanopowders were prepared by co-precipitation and eco-friendly green combustion route using plant latex. • Both the products show excellent chromaticity coordinates in the white region, which were quite useful for white LED’s. • Thermoluminescence response of the Dy{sub 2}O{sub 3} product prepared by green synthesis was higher when compared to co-precipitation route. • Structural parameters of Dy{sub 2}O{sub 3} were estimated using Rietveld refinement. • The development of nanosize materials using eco-friendly resources was an attractive non-hazardous chemical route. - Abstract: Dysprosium oxide (Dy{sub 2}O{sub 3}) nanopowders were prepared by co-precipitation (CP) and eco-friendly green combustion (GC) routes. SEM micrographs prepared by CP route show smooth rods with various lengths and diameters while, GC route show porous, agglomerated particles. The results were further confirmed by TEM. Thermoluminescence (TL) responses of the nanopowder prepared by both the routes were studied using γ-rays. A well resolved glow peak at 353 °C along with less intense peak at 183 °C was observed in GC route while, in CP a single glow peak at 364 °C was observed. The kinetic parameters were estimated using Chen’s glow peak route. Photoluminescence (PL) of Dy{sub 2}O{sub 3} shows peaks at 481, 577, 666 and 756 nm which were attributed to Dy{sup 3+} transitions of {sup 4}F{sub 9/2}⟶{sup 6}H{sub 15/2}, {sup 6}H{sub 13/2}, {sup 6}H{sub 11/2} and {sup 6}H{sub 9/2}, respectively. Color co-ordinate values were located in the white region as a result the product may be useful for the fabrication of WLED’S.

  9. Preparation and photocatalytic degradation performance of Ag{sub 3}PO{sub 4} with a two-step approach

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jiwen; Ji, Xiaojing; Li, Xian; Hu, Xianghua; Sun, Yanfang; Ma, Jingjun, E-mail: mjjwjpmartin@sina.com; Qiao, Gaowei

    2016-05-30

    Highlights: • Ag{sub 3}PO{sub 4} photocatalysts were synthesized via one-step and two-step ion-exchange reaction. • Photocatalytic properties of Ag{sub 3}PO{sub 4} photocatalysts was investigated, the result indicated the Ag{sub 3}PO{sub 4} (2) was higher than that of Ag{sub 3}PO{sub 4} (1) under the same experimental condition. • Ag{sub 3}PO{sub 4} (2) particles were larger than Ag{sub 3}PO{sub 4} (1) particles and many polygonal-shaped surfaces could be clearly observed in the Ag{sub 3}PO{sub 4} (2) particles. - Abstract: Ag{sub 3}PO{sub 4} photocatalysts were prepared via two and one-step through a facile ion-exchange route. The photocatalysts were then characterized through powder X-ray diffraction, scanning electron microscopy and UV–vis diffuse reflectance spectroscopy. The photocatalytic activity of the samples was evaluated on the basis of the photocatalytic degradation of methyl orange (MO) and methylene blue (MB) under solar irradiation. The MO degradation rate of the Photocatalyst synthesized by the two-step ion-exchange route was 89.18% in 60 min. This value was four times that of the Photocatalyst synthesized by the one-step approach.The MB degradation rate was 97% in 40 min. After six cycling runs were completed, the MO degradation rate was 73%.

  10. Synthesis and characterization of Gd{sub 2}O{sub 3} doped UO{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Soldati, A.L., E-mail: asoldati@cab.cnea.gov.ar [Centro Atómico Bariloche (CAB) – Comisión Nacional de Energía Atómica (CNEA), Av. Bustillo 9500, CP: 8400 Bariloche (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Av. De los Pioneros 2300, CP: 8400 Bariloche (Argentina); Gana Watkins, I. [Centro Atómico Bariloche (CAB) – Comisión Nacional de Energía Atómica (CNEA), Av. Bustillo 9500, CP: 8400 Bariloche (Argentina); Fernández Zuvich, A. [Centro Atómico Bariloche (CAB) – Comisión Nacional de Energía Atómica (CNEA), Av. Bustillo 9500, CP: 8400 Bariloche (Argentina); Instituto Balseiro, Universidad Nacional de Cuyo, Av. Bustillo 9500, CP: 8400 Bariloche (Argentina); Napolitano, F.; Troiani, H. [Centro Atómico Bariloche (CAB) – Comisión Nacional de Energía Atómica (CNEA), Av. Bustillo 9500, CP: 8400 Bariloche (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Av. De los Pioneros 2300, CP: 8400 Bariloche (Argentina); and others

    2016-10-15

    UO{sub 2} nanoparticles doped with 4, 8, 10 and 15 wt% Gd{sub 2}O{sub 3}were synthesized by a reverse strike method. Crystal structure and chemical homogeneity were evaluated using a combination of X-ray diffraction and microscopy tools. An exhaustive study of the composition and its homogeneity at the micro and at the nanometer level was carried out in this nuclear fuel material. Field Emission Gun Scanning and Transmission Electron Microscopy images revealed the presence of micrometer scale agglomerates of nanoparticles, with rounded morphology and an average crystallite size of 100 nm. Rietveld refinements of high-statistic X-ray Diffraction data determined the crystal structure and composition. Furthermore, Energy Dispersive Spectroscopy using a 2 nm{sup 2} spot on the sample surface determined a Gd concentration variation around the average of ±5% in different spots of a single crystallite and of ±10% between different crystallites. However, when measuring large amounts of nanoparticles the concentration averages, producing a homogeneous composition distribution at the micrometer scale. - Highlights: • Synthesis of 4, 8, 10 and 15wt% Gd{sub 2}O{sub 3} doped UO{sub 2} nanoparticles. • Crystallite sizes around 100 nm and rounded morphology. • 90% Gd distribution homogeneity between particles for the less concentrated sample. • High Statistic X-ray Rietveld analysis determined an U{sub 1−x}Gd{sub x}O{sub 2−δ} fcc structure. • Phases with similar crystal structure and symmetry, but different lattice parameter.

  11. Immobilizing LaFeO{sub 3} nanoparticles on carbon spheres for enhanced heterogeneous photo-Fenton like performance

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Kaixuan [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230601 (China); Niu, Helin, E-mail: niuhelin@ahu.edu.cn [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230601 (China); Chen, Jingshuai; Song, Jiming; Mao, Changjie; Zhang, Shengyi [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230601 (China); Gao, Yuanhao [Institute of Surface Micro and Nano Materials, Xuchang University, Henan 461000 (China)

    2017-05-15

    Highlights: • LaFeO{sub 3} nanoparticles sub–10 nm were successfully immobilized on monodisperse carbon spheres for the first time through a facile and environmental friendly ultrasonic assisted surface ions adsorption method. • LaFeO{sub 3}/C nanocomposite exhibits much higher photo-Fenton like catalytic activity than LaFeO{sub 3}. • The superior property was attributed to the synergistic effects from the photo-Fenton like process and the presence of monodisperse carbon spheres. - Abstract: LaFeO{sub 3} nanoparticles immobilized on the surface of monodisperse carbon spheres have been obtained through a facile and environmentally friendly ultrasonic assisted surface ions adsorption method. The LaFeO{sub 3}/C nanocomposite was evaluated as photo-Fenton like catalyst for the degradation of Rhodamine B (RhB) under visible light irradiation (λ > 420 nm). The LaFeO{sub 3}/C nanocomposite possesses high specific surface area compared with pure LaFeO{sub 3} and significantly enhanced photo-Fenton like catalytic performance. The possible formation process of the LaFeO{sub 3}/C nanocomposite and the mechanism for photo-Fenton like reaction were discussed. The superior property was attributed to the synergistic effects from the photo-Fenton like process and the presence of carbon spheres. In addition, the heterogeneous process led to better recyclability of this type of catalyst.

  12. Preparation of planar CH{sub 3}NH{sub 3}PbI{sub 3} thin films with controlled size using 1-ethyl-2-pyrrolidone as solvent

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Qiuyan; Chu, Yixia [Engineering Laboratory of Functional Optoelectronic Crystalline Materials of Hebei Province, School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300132 (China); Zheng, Xuerong [Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education, School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Liu, Zhenya; Liang, Liming [Engineering Laboratory of Functional Optoelectronic Crystalline Materials of Hebei Province, School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300132 (China); Qi, Jiakun [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Zhang, Xin [Engineering Laboratory of Functional Optoelectronic Crystalline Materials of Hebei Province, School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300132 (China); Liu, Gang [School of Chemical Engineering, Hebei University of Technology, Tianjin 300132 (China); Liu, Hui, E-mail: liuhuihebut@163.com [Engineering Laboratory of Functional Optoelectronic Crystalline Materials of Hebei Province, School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300132 (China); Chen, Hongjian [Engineering Laboratory of Functional Optoelectronic Crystalline Materials of Hebei Province, School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300132 (China); Liu, Caichi, E-mail: ccliu@hebut.edu.cn [Engineering Laboratory of Functional Optoelectronic Crystalline Materials of Hebei Province, School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300132 (China)

    2016-06-25

    Recently, planar perovskite solar cells based on CH{sub 3}NH{sub 3}PbI{sub 3} have attracted many researcher's interest due to their unique advantages such as simple cell architecture, easy fabrication and potential multijunction construction comparing to the initial mesoporous structure. However, the preparation of planar perovskite films with high quality is still in challenge. In this paper, we developed a vapor-assisted solution process using a novel and green solvent of 1-Ethyl-2-pyrrolidone (NEP) instead of the traditional N, N-dimethylformamide (DMF) to construct a high-quality perovskite CH{sub 3}NH{sub 3}PbI{sub 3} thin film with pure phase, high compactness, small surface roughness and controlled size. The phase evolution and growth mechanism of the perovskite films are also discussed. Utilizing the NEP of low volatility and moderate boiling point as solvent, we dried the PbI{sub 2}-NEP precursor films at different temperature under vacuum and then obtained PbI{sub 2} thin films with different crystalline degree from amorphous to highly crystalline. The perovskite films with crystal size ranged from hundreds of nanometers to several micrometers can be prepared by reacting the PbI{sub 2} films of different crystalline degree with CH{sub 3}NH{sub 3}I vapor. Moreover, planar-structured solar cells combining the perovskite film with TiO{sub 2} and spiro-OMeTAD as the electron and holes transporting layer achieves a power conversion efficiency of 10.2%. - Highlights: • A novel and green solvent of 1-Ethyl-2-pyrrolidone (NEP) was used to construct high-quality perovskite CH{sub 3}NH{sub 3}PbI{sub 3} thin film. • The CH{sub 3}NH{sub 3}PbI{sub 3} grain with different sizes ranged from hundreds of nanometers to several micrometers can be obtained. • Planar-structured perovskite CH{sub 3}NH{sub 3}PbI{sub 3} solar cells using NEP as solvent achieves a power conversion efficiency of 10.2%.

  13. Antiferromagnetic resonance in multiferroic YMnO{sub 3} and LuMnO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Kamensky, D.; Ozerov, M.; Cizmar, E.; Wosnitza, J.; Zvyagin, S. [Dresden High Magnetic Field Laboratory (HLD), Forschungszentrum Dresden - Rossendorf, 01314 Dresden (Germany)

    2009-07-01

    Multiferroic rare-earth manganites have attracted much attention because of the coexistence of ferroelectric and magnetic order. Combining conventional far-infrared Fourier-transform and THz-range free electron laser electron spin resonance (ESR) techniques, magnetic excitations in the hexagonal multiferroic materials YMnO{sub 3} and LuMnO{sub 3} have been studied. In the antiferromagnetically (AFM) ordered phase the gap in the excitation spectrum ({proportional_to}42 and {proportional_to}48 cm{sup -1} for YMnO{sub 3} and LuMnO{sub 3}, respectively) was observed directly. Similar slope of the frequency-field dependences of the AFM resonance modes, {proportional_to} 0.5 cm{sup -1}/T, was found for both compounds. A fine structure of the AFM resonance absorption has been revealed by means of high-resolution ESR techniques, which can be explained taking into account a finite interaction between the neighboring Mn{sup 3+} layers.

  14. Influence of Al{sub 2}O{sub 3} addition on microstructure and mechanical properties of 3YSZ-Al{sub 2}O{sub 3} composites

    Energy Technology Data Exchange (ETDEWEB)

    Abden, Md. Jaynul [International Islamic Univ., Chittagong (Bangladesh). Dept. of Electrical and Electronic Engineering; Afroze, Jannatul Dil [Noakhali Science and Technology Univ. (Bangladesh). Faculty of Science and Engineering; Gafur, Md. Abdul [Bangladesh Council of Scientific and Industrial Research, Dhaka (Bangladesh). Pilot Plant and Process Development Centre; Chowdhury, Faruque-Uz-Zaman [Chittagong University of Engineering and Technology (Bangladesh). Dept. of Physics

    2015-07-01

    The effect of the amount of Al{sub 2}O{sub 3} content on microstructure, tetragonal phase stability and mechanical properties of 3YSZ-Al{sub 2}O{sub 3} composites are investigated in this study. The ceramic composites are obtained by means of uniaxial compacting at 210 MPa and green compacts are sintered at 1550 C for 3 h in air. The monoclinic zirconia (m-ZrO{sub 2}) phase has completely been transformed into tetragonal zirconia (t-ZrO{sub 2}) phase with corresponding higher Al{sub 2}O{sub 3} content. The t-ZrO{sub 2} grains induce transgranular fracture mode that has contribution in improvement of fracture toughness. The maximum flexural strength of 340 MPa, Vickers hardness value of 14.31 GPa and fracture toughness of 5.1 MPa x m{sup 1/2} in the composition containing 40 wt.-% Al{sub 2}O{sub 3} is attributed to the microstructure with t-ZrO{sub 2} grains as inter- and intragranular particles in the Al{sub 2}O{sub 3} grains, which makes it suitable for dental applications.

  15. Hydroxide precursors to produce nanometric YCrO{sub 3}: Characterization and conductivity analysis

    Energy Technology Data Exchange (ETDEWEB)

    Durán, A., E-mail: dural@cnyn.unam.mx [Universidad Nacional Autónoma de México, Centro de Nanociencias y Nanotecnología, Km. 107 Carretera Tijuana-Ensenada, Apartado Postal 14, C.P. 22800, Ensenada, B.C. (Mexico); Meza F, C. [Universidad Nacional Autónoma de México, Centro de Nanociencias y Nanotecnología, Km. 107 Carretera Tijuana-Ensenada, Apartado Postal 14, C.P. 22800, Ensenada, B.C. (Mexico); Arizaga, Gregorio Guadalupe Carbajal, E-mail: gregoriocarbajal@yahoo.com.mx [Departamento de Química, Universidad de Guadalajara, Marcelino García Barragán 1421, C.P. 44430, Guadalajara, Jalisco (Mexico)

    2012-06-15

    Highlights: ► Y/Cr mixed hydroxide was precipitated with gaseous ammonia. ► The hydroxide treated at 1373 K formed YCrO{sub 3} crystals with 20 nm diameter. ► Electrical properties were different than those found in other methods of synthesis. ► E{sub act} suggests small-polarons as conduction mechanisms. -- Abstract: A precursor to produce perovskite-type YCrO{sub 3} was precipitated by bubbling gaseous ammonia into an yttrium/chromium salts solution. X-ray diffraction showed that the as-prepared powders were amorphous. Thermal treatment between 1273 and 1373 K, leads to formation of polycrystalline YCrO{sub 3} with crystal sizes around 20 nm. High resolution X-ray photoelectron spectra showed uniform chemical environment for yttrium and chromium in the amorphous hydroxide and crystalline YCrO{sub 3}. Shifts between Y 3d{sub 5/2} and Cr 2p{sub 3/2} binding energy suggest redistribution or charge transfer between yttrium and chromium ions in the YCrO{sub 3} structure. The electrical properties of YCrO{sub 3}, whose precursors were precipitated with gaseous ammonia are different than those prepared by combustion synthesis. Electrical conductivity presents a sudden increase at ∼473 K, which is associated to the grain size and morphology of the crystallites. The redistribution of charge between Y(III) and Cr(III) is thermally activated by the hopping of small-polarons, which are characterized by the Arrhenius law as the conductive mechanism.

  16. Correlative characterization of primary Al{sub 3}(Sc,Zr) phase in an Al–Zn–Mg based alloy

    Energy Technology Data Exchange (ETDEWEB)

    Li, J.H., E-mail: jie-hua.li@hotmail.com [Institute of Casting Research, Montanuniversität Leoben, A-8700 Leoben (Austria); Wiessner, M. [Materials Center Leoben Forschung GmbH, A-8700 Leoben (Austria); Albu, M. [Institute for Electron Microscopy and Nanoanalysis, Graz University of Technology, Center for Electron Microscopy (Austria); Wurster, S. [Department of Materials Physics, Montanuniversität Leoben, Erich Schmid Institute of Materials Science of the Austrian Academy of Sciences, A-8700 Leoben (Austria); Sartory, B. [Materials Center Leoben Forschung GmbH, A-8700 Leoben (Austria); Hofer, F. [Institute for Electron Microscopy and Nanoanalysis, Graz University of Technology, Center for Electron Microscopy (Austria); Schumacher, P. [Institute of Casting Research, Montanuniversität Leoben, A-8700 Leoben (Austria); Austrian Foundry Research Institute, A-8700 Leoben (Austria)

    2015-04-15

    Three-dimensional electron backscatter diffraction, focused ion beam, transmission electron microscopy and energy filtered transmission electron microscopy were employed to investigate the structural information of primary Al{sub 3}(Sc,Zr) phase, i.e. size, shape, element distribution and orientation relationship with the α-Al matrix. It was found that (i) most primary Al{sub 3}(Sc,Zr) phases have a cubic three-dimensional morphology, with a size of about 6–10 μm, (ii) most primary Al{sub 3}(Sc,Zr) phases are located within the α-Al matrix, and exhibit a cube to cube orientation relationship with the α-Al matrix, and (iii) a layer by layer growth was observed within primary Al{sub 3}(Sc,Zr) phases. Al, Cu, Si and Fe are enriched in the α-Al matrix between the layers of cellular eutectic Al{sub 3}(Sc,Zr) phase, while Sc, Ti and Zr are enriched in small Al{sub 3}(Sc,Zr) phases. A peritectic reaction and subsequent eutectic reaction between Al{sub 3}Sc and Al was proposed to interpret the observed layer by layer growth. This paper demonstrates that the presence of impurities (Fe, Si, Cu, Ti) in the diffusion field surrounding the growing Al{sub 3}(Sc,Zr) particle enhances the heterogeneous nucleation of Al{sub 3}(Sc,Zr) phases. - Highlights: • Most fine cubic primary Al{sub 3}(Sc,Zr) phases were observed within the α-Al matrix. • A layer by layer growth within primary Al{sub 3}(Sc,Zr) phase was observed. • A peritectic and subsequent eutectic reaction between Al{sub 3}Sc and Al was proposed. • Impurities in diffusion fields enhance heterogeneous nucleation of Al{sub 3}(Sc,Zr)

  17. Density of molten salt Mixtures of eutectic LiCl-KCl containing UCl{sub 3}, CeCl{sub 3}, or LaCl{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, C.; Simpson, M. F. [Dept. of Metallurgical Engineering, University of Utah, Salt Lake City (United States)

    2017-06-15

    Densities of molten salt mixtures of eutectic LiCl-KCl with UCl{sub 3}, CeCl{sub 3}, or LaCl{sub 3} at various concentrations (up to 13 wt%) were measured using a liquid surface displacement probe. Linear relationships between the mixture density and the concentration of the added salt were observed. For LaCl{sub 3} and CeCl{sub 3}, the measured densities were signifcantly higher than those previously reported from Archimedes’ method. In the case of LiCl-KCl-UCl{sub 3}, the data ft the ideal mixture density model very well. For the other salts, the measured densities exceeded the ideal model prediction by about 2%.

  18. Conductivity of CH{sub 3}NH{sub 3}PbI{sub 3} thin film perovskite stored in ambient atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Gebremichael, Bizuneh, E-mail: bizunehme@gmail.com [Physics Department, Addis Ababa University, Addis Ababa, P.O. Box 1176 (Ethiopia); Alemu, Getachew [Physics Department, Addis Ababa University, Addis Ababa, P.O. Box 1176 (Ethiopia); Tessema Mola, Genene [School of Chemistry & Physics, University of KwaZulu-Nat al, Pietermaritzburg Campus, Private Bag X01, Scottsville 3209 (South Africa)

    2017-06-01

    Time dependent conductivity loss in CH{sub 3}NH{sub 3}PbI{sub 3} thin film perovskite stored in ambient atmosphere were studied based on electrical and optical measurements. Recent investigations on thin film perovskite solar cell suggest that in the steady state operation of the device, the V{sub oc} is unchanged by continuous illumination of light. Rather the reduction in the power conversion efficiency is caused by significant reduction of the short circuit current (J{sub sc}). In this paper, the effect of light on the optical absorption and electrical conductivity of the CH{sub 3}NH{sub 3}PbI{sub 3} thin film which is deposited on a glass substrate is investigated. The temperature dependent conductivity measurements indicated that the dominant conduction mechanism in the film perovskite is electronic rather than ionic.

  19. The effect of electron donating and withdrawing groups on the morphology and optical properties of Alq{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Duvenhage, M.M. [Department of Physics, University of the Free State, PO Box 339, Bloemfontein ZA9300 (South Africa); Visser, H.G. [Department of Chemistry, University of the Free State, Bloemfontein ZA9300 (South Africa); Ntwaeaborwa, O.M. [Department of Physics, University of the Free State, PO Box 339, Bloemfontein ZA9300 (South Africa); Swart, H.C., E-mail: swarthc@ufs.ac.za [Department of Physics, University of the Free State, PO Box 339, Bloemfontein ZA9300 (South Africa)

    2014-04-15

    By adding electron donating (EDG) and withdrawing groups (EWG) to the Tris-(8-hydroxyquinoline) aluminum (Alq{sub 3}) molecule, the emission color can be tuned. In this study the effect of EDG and EWG on the morphology and optical properties of Alq{sub 3} were investigated. Alq{sub 3} powders was synthesized with an EDG (–CH{sub 3}) substituted at positions 5 and 7 ((5,7-dimethyl-8-hydroxyquinoline) aluminum) and EWG (–Cl) at position 5 ((5-chloro-8-hydroxyquinoline) aluminum). A broad absorption band at ∼380 nm was observed for Alq{sub 3}. The bands of the substituted samples were red-shifted. The un-substituted Alq{sub 3} showed a high intensity emission peak at 500 nm. The –Cl and –CH{sub 3} samples showed a red-shift of 33 and 56 nm respectively. The morphology of the samples was studied using a scanning electron microscope. The photo degradation of the samples was also investigated and the dimethyl sample shows the least degradation to the UV irradiation over the 24 h of continuous irradiation.

  20. Synthesis, morphology and microstructure of pomegranate-like hematite ({alpha}-Fe{sub 2}O{sub 3}) superstructure with high coercivity

    Energy Technology Data Exchange (ETDEWEB)

    Tadic, Marin, E-mail: marint@vinca.rs [Condensed Matter Physics Laboratory, Vinca Institute, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia); Citakovic, Nada [Military Academy, Generala Pavla Jurisica Sturma 33, University of Belgrade, 11000 Belgrade (Serbia); Panjan, Matjaz [Jozef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia); Stanojevic, Boban [Vinca Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade, University of Belgrade (Serbia); Markovic, Dragana [Condensed Matter Physics Laboratory, Vinca Institute, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia); Jovanovic, Dorde [Center for Solid State Physics and New Materials, Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade (Serbia); Spasojevic, Vojislav [Condensed Matter Physics Laboratory, Vinca Institute, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia)

    2012-12-05

    Highlights: Black-Right-Pointing-Pointer We found superior magnetic properties of the hematite ({alpha}-Fe{sub 2}O{sub 3}). Black-Right-Pointing-Pointer TEM and HRTEM images show a pomegranate-like superstructure. Black-Right-Pointing-Pointer Magnetic measurements display high coercivity H{sub C} = 4350 Oe at the room temperature. - Abstract: We found novel and superior magnetic properties of the hematite ({alpha}-Fe{sub 2}O{sub 3}) that originate from an internal microstructure of particles and strong inter-particle interactions between nanocrystal sub-units. The hematite particles were synthesized by thermal decomposition of iron (III) nitrate without any template or surfactant. The purity, size, crystallinity, morphology, microstructure and magnetic features of the as-prepared particles were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), Raman spectroscopy (RS) and SQUID magnetometry. An XRD study reveals a pure phase of {alpha}-Fe{sub 2}O{sub 3} whereas TEM shows {alpha}-Fe{sub 2}O{sub 3} spheres with a diameter of about 150 nm. RS also shows high quality and purity of the sample. Moreover, TEM and HRTEM images show a pomegranate-like superstructure and evidence that the spherical particles are composed of individual well-crystallized nanoparticle sub-units (self-assembled nanoparticles) with a size of about 20 nm. Magnetic measurements display hysteretic behavior at the room temperature with remanent magnetization M{sub r} = 0.731 emu/g, saturation magnetization M{sub S} = 6.83 emu/g and coercivity H{sub C} = 4350 Oe, as well as the Morin transition at T{sub M} = 261 K. These results and comparison with those in the literature reveal that the sample has extremely high coercivity. The magnetic properties of the sample are discussed in relation to morphology, internal microstructure, surface

  1. Size effects and interactions in La{sub 0.7}Ca{sub 0.3}MnO{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Manh, D.H., E-mail: manhdh@ims.vast.ac.vn [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay Distr., Ha Noi (Viet Nam); Phong, P.T. [Nha Trang Pedagogic College, Khanh Hoa Province (Viet Nam); Thanh, T.D.; Nam, D.N.H.; Hong, L.V.; Phuc, N.X. [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay Distr., Ha Noi (Viet Nam)

    2011-02-03

    Research highlights: > The magnetic characteristic and analysis have been done for La{sub 0.7}Ca{sub 0.3}MnO{sub 3} nanoparticles with average particle size from 16 to 73 nm fabricated by reactive milling and thermal processing methods. Magnetic measurements showed the existence of magnetic interaction between particles. A mean field approximation can describe well magnetic behavior of interacting nanoparticle assemblies. The blocking temperature decreases with the increase of interaction strength or particle size, which are suggested to be due to contribution of strong magnetic anisotropy. The reduction of saturation magnetization with surface/volume ratio is mainly due to the formation of a nonmagnetic surface shell around the nanoparticles. The temperature dependence of magnetization based on a thermal distribution of spin waves and fit results to a power law T{sup {epsilon}} showed that {epsilon} decreases from 1.67 to 1.56 as the particle size increases from 16 to 73 nm. - Abstract: La{sub 0.7}Ca{sub 0.3}MnO{sub 3} (LCMO) nanoparticles with average diameter of 16-73 nm were prepared by reactive milling and thermal processing methods. Interaction and size effects on the magnetic properties of the LCMO nanoparticle samples were investigated. Phenomena related to the interparticle interaction, such as an un-overlapping of the M(H{sub ext},T)/M{sub S} vs. H{sub ext}/T scaling plots and a Curie-Weiss rather than Curie law behavior of the dc susceptibility at high temperatures were analyzed. The magnetization curves of interacting nanoparticles were well described by using the mean-field approximation. The dependence of the blocking temperature T{sub B} on the strength of the interactions, magnetic anisotropy, as well as the thermal dependence of magnetization deviates from the expected Bloch law was also estimated.

  2. Effects of Tb{sup 3+} concentration on the La{sub 2}Sr{sub 3}(BO{sub 3}){sub 4}: X% Tb{sup 3+} polycrystalline nanophosphor

    Energy Technology Data Exchange (ETDEWEB)

    Mlotswa, D.V. [Physics Department, University of the Free State, Private Bag x13, Phuthaditjhaba 9866 (South Africa); Madihlaba, R.M. [Chemistry Department, University of the Western Cape, Private Bag x17, Bellville 7535 (South Africa); Koao, L.F. [Physics Department, University of the Free State, Private Bag x13, Phuthaditjhaba 9866 (South Africa); Onani, M.O., E-mail: monani@uwc.ac.za [Chemistry Department, University of the Western Cape, Private Bag x17, Bellville 7535 (South Africa); Dejene, F.B. [Physics Department, University of the Free State, Private Bag x13, Phuthaditjhaba 9866 (South Africa)

    2016-01-01

    A new green phosphor, La{sub 2}Sr{sub 3}(BO{sub 3}){sub 4}): x% Tb{sup 3+} was fabricated by solution-combustion method using urea as a fuel and ammonium nitrate as an oxidizer. The phosphor was characterised using Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), Differential scanning calorimetry (DSC), Energy dispersive spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence spectroscopy (PL. The results exhibit that La{sub 2}Sr{sub 3}(BO{sub 3}){sub 4}): x% Tb{sup 3+} phosphor has the strongest excitation at 209 nm with a full-width at half-maximum (FWHM) of 20 nm, and can emit bright green light at 545 nm under 209 nm excitation. The optimum concentration for Tb{sup 3+} in La{sub 2}Sr{sub 3}(BO{sub 3}){sub 4}): x% Tb{sup 3+} is 0.033 mol%. The prominent green luminescence was due to the {sup 5}D{sub 4}–{sup 7}F{sub 5} transition of Tb{sup 3+} ion. Herein, the green phosphors are promising good candidates employed in tri-color lamps.

  3. Improving pure red upconversion emission of Co-doped Y{sub 2}O{sub 3}:Yb{sup 3+}–Er{sup 3+} nanocrystals with a combination of sodium sulfide and surfactant Pluronic-F127

    Energy Technology Data Exchange (ETDEWEB)

    López-Luke, T., E-mail: tzarara@cio.mx [Centro de Investigaciones en Óptica, A.P. 1-948, León, Gto. 37160, México (Mexico); De la Rosa, E., E-mail: elder@cio.mx [Centro de Investigaciones en Óptica, A.P. 1-948, León, Gto. 37160, México (Mexico); Campos Villalobos, I. [Centro de Investigaciones en Óptica, A.P. 1-948, León, Gto. 37160, México (Mexico); Rodriguez, R.A. [Universidad de Guadalajara, Unidad Lagos, Lagos de Moreno, Jal. 47460, México (Mexico); Ángles-Chávez, C. [Instituto Mexicano del Petróleo, Cd. México, D.F. 07730, México (Mexico); Salas, P. [Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, A.P. 1-1010, Querétaro, Qro. 76000, México (Mexico); Wheeler, Damon A.; Zhang, J.Z. [Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064 (United States)

    2014-01-15

    Nanocrystals of Y{sub 2}O{sub 3}:Yb{sup 3+}–Er{sup 3+} (2:1 mol% Yb{sup 3+}:Er{sup 3+}) were prepared by a novel precipitation technique using Na{sub 2}S and Pluronic-F127 (PF127) surfactant. Crystal structure, particle size, red emission intensity and fluorescence decay lifetimes were determined using microscopy and spectroscopy techniques. TEM analysis indicates that the average particle size ranged from 40 to 70 nm. The nanocrystals showed a strong red emission band centered at 663 nm after excitation at 970 nm. The upconverted signal intensity was improved 250% with an optimum concentration of Na{sub 2}S (0.48 M) and PF127 (0.1 mM). The improvement was explained in terms of the reduction of surface contaminants as well as the cubic crystalline phase of the parent Y{sub 2}O{sub 3} material. Interestingly, the formation of sulfates (SO{sub 4}{sup 2−}) is faster than that of O–H, which is responsible for quenching the red and green emissions. The results suggest that Na{sub 2}S and PF127 are good candidates for surface passivation, especially when used in conjunction. The preparation of Y{sub 2}O{sub 3}:Yb{sup 3+}–Er{sup 3+} using Na{sub 2}S with strong red emission band was produced at a lower cost than that of other sulfuration processes. -- Highlights: • . • Strong red emission band centered at 663 nm was obtained after excitation at 970 nm. • Yb-Er codoped Y2O3 nanocrystals with average size ranging from 40 to 70 nm. • Improvement of the red emission in Y2O3:Yb-Er nanocrystals by the introduction of sodium sulfide and pluronic. • Passivation of nanocrystal surface with sodium sulfide and pluoronic.

  4. Synthesis and characterization of pure and Tb/Cu doped Alq{sub 3} nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Salah, Numan, E-mail: nsalah@kau.edu.sa [Center of Nanotechnology, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Habib, Sami S. [Center of Nanotechnology, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Khan, Zishan H. [Department of Applied Sciences, Faculty of Engineering and Technology, Jamia Millia, Islamia (Central University), New Delhi 110025 (India); Alharbi, Najlaa D. [Center of Nanotechnology, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Sciences Faculty for Girls, King Abdulaziz University, Jeddah-21589 (Saudi Arabia)

    2013-11-15

    Tris (8-hydroxyquinoline) aluminum (Alq{sub 3}) is an organic semiconductor molecule, widely used in optoelectronic devices. In this work we report on fabricating different nanostructures of Alq{sub 3} and characterize them using different techniques. Nanostructured films of Alq{sub 3} were grown using the physical vapor condensation and thermal-vapor transport methods. The as synthesized films were characterized by X-ray diffraction, scanning electron microscope, energy dispersive spectroscopy and absorption spectra. Nanoparticles and nanorods/nanowires are observed in the synthesized films. Tb and Cu doped Alq{sub 3} films were also produced and studied for their photoluminescence (PL) properties. When the original powder sample of Alq{sub 3} was excited by 378 nm, one broad PL emission band is observed at around 515 nm. The pure nanoparticles film shows similar band with a drastic increase in the intensity by a factor of 2. This has been attributed to the large specific surface area, which might has increased the absorption and then the quantum yields. The Tb and Cu doped films show also similar band with a slight shift in the peak position to the blue region, but with further enhancement in the peak intensity, particularly that of Cu. The PL intensity of Cu doped sample is around 1.5 times stronger than that of the pure Alq{sub 3} nanoparticles. This remarkable result on obtaining highly luminescent nanomaterial based on Cu doped Alq{sub 3} nanoparticles film might be useful for future organic light emitting diode display devices. -- Highlights: • Films of Alq{sub 3} nanostructures were grown using different methods. • The PL intensity of Alq{sub 3} in its nanostructure form is enhanced by a factor of 2. • This enhancement is attributed to the large specific surface area of the nanostructures. • Films of Alq{sub 3} nanoparticles doped with Tb and Cu showed further PL enhancement. • The Tb and Cu ions could contribute to the PL intensity of the green

  5. Effect of Ru on LaCoO{sub 3} perovskite-derived catalyst properties tested in oxidative reforming of diesel

    Energy Technology Data Exchange (ETDEWEB)

    Navarro, R.M.; Alvarez-Galvan, M.C.; Villoria, J.A.; Gonzalez-Jimenez, I.D.; Fierro, J.L.G. [Instituto de Catalisis y Petroleoquimica (CSIC), C/Marie Curie no. 2, Cantoblanco 28049 Madrid (Spain); Rosa, F. [Centro de Experimentacion de ' El Arenosillo' (CEDEA), Instituto Nacional de Tecnica Aeroespacial (INTA), Mazagon-Moguer, 21130 Huelva (Spain)

    2007-05-11

    The oxidative reforming of diesel over Co/La{sub 2}O{sub 3} and Ru-Co/La{sub 2}O{sub 3} catalysts derived from LaCoO{sub 3} perovskite precursors was studied. Physicochemical characterization by XPS, TPR and XRD revealed that the incorporation of Ru to LaCoO{sub 3} produces changes in LaCoO{sub 3} evidenced by a smaller size of the LaCoO{sub 3} particles and cobalt segregation on the LaCoO{sub 3} surface. The modifications in the structure of LaCoO{sub 3} induced by the addition of Ru directly affect the dispersion and morphology of Co particles developed under the reaction. The active phases derived from pretreatment of perovskites evolve differently with time on stream, being observed that the presence of a greater proportion of perovskite phase in the Ru/LaCoO{sub 3} sample produces an increase in catalyst stability. TPD-MS analysis also indicates that bulk oxygen release from the Ru-Co/La{sub 2}O{sub 3} sample could improve its catalytic behaviour. The characterization of used samples reveals that improvements in the cobalt surface concentration and Co-La{sub 2}O{sub 3} interactions contribute to the better catalytic stability of the Ru-Co/La{sub 2}O{sub 3}-derived catalyst. (author)

  6. Orthorhombic strontium titanate in BaTiO sub 3 -SrTiO sub 3 superlattices

    CERN Document Server

    Rios, S; Jiang, A Q; Scott, J F; Lü, H; Chen, Z

    2003-01-01

    It has been suggested by several authors that SrTiO sub 3 layers in SrTiO sub 3 -BaTiO sub 3 superlattices should be tetragonal and ferroelectric at ambient temperatures, like the BaTiO sub 3 layers, rather than cubic, as in bulk SrTiO sub 3 , and that free-energy minimization requires continuity of the polarization direction. A recent ab initio calculation constrained solutions to this structure. Surprisingly, our x-ray study shows that the SrTiO sub 3 layers are orthorhombic with 0.03% in-plane strain, with the BaTiO sub 3 c-axis matching the SrTiO sub 3 a- and b-axis better than the c-axis; strain energy overcomes the cost in electrostatic energy. (letter to the editor)

  7. Novel electrical conductivity properties in Ca-doped BiFeO{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.; Wang, S. Y., E-mail: shouyu.wang@yahoo.com [Tianjin Normal University, College of Physics and Materials Science (China); Liu, W. F., E-mail: wfliu@tju.edu.cn [Tianjin University, Department of Applied Physics, Institute of Advanced Materials Physics, Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Faculty of Science (China); Xi, X. J. [Tianjin Normal University, College of Physics and Materials Science (China); Zhang, H. [Tianjin University, Department of Applied Physics, Institute of Advanced Materials Physics, Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Faculty of Science (China); Guo, F. [Tianjin Normal University, College of Physics and Materials Science (China); Xu, X. L. [Tianjin University, Department of Applied Physics, Institute of Advanced Materials Physics, Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Faculty of Science (China); Li, M.; Liu, L.; Zhang, C.; Li, X.; Yang, J. B. [Tianjin Normal University, College of Physics and Materials Science (China)

    2015-05-15

    The charge defective structure in Bi{sub 1−x}Ca{sub x}FeO{sub 3} (CBFO, x = 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3) nanoparticles (NPs) ranging from 140 to 25 nm as well as their relations to band gap and leakage current behavior are investigated. It is demonstrated that Ca doping effectively narrows the band gap from ∼2.16 to ∼2.02 eV, due to the appearance and accumulation of oxygen vacancy. Subsequently, enhanced electrical conductivity was obtained in these CBFO NPs, which leads to the appearance of a distinct threshold switching behavior in Ca-doped BFO NPs with higher conductivity at room temperature. Possible mechanisms for Ca doping effects on the electric conduction were discussed upon the interplay of NPs’ size effect and mobile charged defects on the basis of reduced particle size and the increased density of oxygen vacancy analyzed through X-ray photoelectron spectrum.

  8. Surfactant-assisted synthesis of mono-dispersed cubic BaTiO{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Hai, Chunxi [National Institute of Advanced Industrial Science and Technology (AIST), Shimo-Shidami, Moriyama-ku, Nagoya 463-8560 (Japan); Inukai, Koji; Takahashi, Yosuke [Noritake Co., Limited, RD Center, Miyoshi 470-0293 (Japan); Izu, Noriya; Akamatsu, Takafumi; Itoh, Toshio [National Institute of Advanced Industrial Science and Technology (AIST), Shimo-Shidami, Moriyama-ku, Nagoya 463-8560 (Japan); Shin, Woosuck, E-mail: w.shin@aist.go.jp [National Institute of Advanced Industrial Science and Technology (AIST), Shimo-Shidami, Moriyama-ku, Nagoya 463-8560 (Japan)

    2014-09-15

    Mono-dispersed BaTiO{sub 3} nanoparticles have been prepared via the assistance of capping agent poly(vinylpyrrolidone) (PVP). - Highlights: • BaTiO{sub 3} nanoparticles with single cubic crystal structure. • Poor dispersibility of nanoparticles has been overcome by in situ modification way. • Growth competition between BaTiO3 core and polymer shell. - Abstract: In this study, poly(vinylpyrrolidone)-assisted synthesis of mono-dispersed BaTiO{sub 3} nanoparticles have been reported. The various processing parameters, namely, refluxing temperature, KOH concentration, and poly(vinylpyrrolidone) concentration, have been varied, and the effects on the growth of BaTiO{sub 3} particles have been analyzed systematically. X-ray diffraction studies indicated that poly(vinylpyrrolidone) did not affect the crystal structure, but rather influenced the crystal lattice structure. In addition, the use of surfactant poly(vinylpyrrolidone) hindered the agglomeration of the nanoparticles, and facilitated the formation of mono-dispersed core–shell organic/inorganic hybrid nanocomposite. Furthermore, the mineralizer KOH promoted the dissolution of reactants and promoted the crystallization of BaTiO{sub 3} particles. Accordingly, the dissolution-precipitation scheme was believed to be the mechanism underlying the formation of BaTiO{sub 3} particles. This was further substantiated by the experimental observations, which indicated that the nucleation and crystallization of the particles was affected by the KOH concentration in the reaction system. Finally, the formation of mono-dispersed core–shell nanocomposites proceeded via reaction limited cluster aggregation. We believe that the method proposed in this study could be extended for the synthesis of mono-dispersed nanoparticles for industrial applications.

  9. Hydrothermal synthesis of uniform WO{sub 3} submicrospheres using thiourea as an assistant agent

    Energy Technology Data Exchange (ETDEWEB)

    Su, X.T.; Xiao, F.; Lin, J.L. [Ministry Key Laboratory of Oil and Gas Fine Chemicals, College of Chemistry and Chemical Engineering, Xinjiang University, No. 14 Shengli Road, Urumqi 830046 (China); Jian, J.K. [College of Physics Science and Technology, Xinjiang University, No. 14 Shengli Road, Urumqi 830046 (China); Li, Y.N.; Sun, Q.J. [Ministry Key Laboratory of Oil and Gas Fine Chemicals, College of Chemistry and Chemical Engineering, Xinjiang University, No. 14 Shengli Road, Urumqi 830046 (China); Wang, J.D., E-mail: laofuzi193@163.com [Ministry Key Laboratory of Oil and Gas Fine Chemicals, College of Chemistry and Chemical Engineering, Xinjiang University, No. 14 Shengli Road, Urumqi 830046 (China)

    2010-08-15

    Nearly monodisperse tungsten trioxide submicrospheres have been synthesized with tungsten acid and HCl as the starting materials and thiourea as a structure-directing agent through a facile hydrothermal method. The obtained products were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy and energy dispersive X-ray, respectively. The results show that the WO{sub 3} submicrospheres are monodisperse with a diameter of about 800-1000 nm. The morphology of the products gradually evolutes from rods to spheres with increase of the reaction time. The formation mechanism of the WO{sub 3} submicrospheres is primarily discussed.

  10. Superparamagnetic polyimide/{gamma}-Fe{sub 2}O{sub 3} nanocomposite films: Preparation and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Zhan Jiayu; Tian Guofeng; Jiang Lizhong; Wu Zhanpeng [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Wu Dezhen [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)], E-mail: wdz@mail.buct.edu.cn; Yang Xiaoping; Jin Riguang [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)

    2008-07-31

    Polyimide/{gamma}-Fe{sub 2}O{sub 3} nanocomposite films with superparamagnetic behavior have been prepared by thermal curing of the magnetite (Fe{sub 3}O{sub 4}) nanoparticles-containing poly(amic acid) (PAA) derived from pyromellitic dianhydride (PMDA) and 4,4'-oxydianiline (4,4'-ODA) in N,N-dimethylacetamide (DMAc). To improve the dispersion of the doped nanoparticles, the amine-functionalized Fe{sub 3}O{sub 4} nanoparticles reacted with the PMDA dianhydride in DMAc firstly, and then polymerization was carried out by adding 4,4'-ODA and then PMDA to form the PAA-grafted magnetic particles. Thermal treatment of the Fe{sub 3}O{sub 4}-doped precursor film converted the PAA into its final polyimide form with concomitant transformation of Fe{sub 3}O{sub 4} into {gamma}-Fe{sub 2}O{sub 3}, yielding a polyimide film with superparamagnetic behavior. The distribution of nanoparticles in the polymer matrix was investigated by transmission electron microscopy and field emission scanning electron microscopy. The nanoparticles and composite films were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, magnetic and mechanical measurement.

  11. About room temperature ferromagnetic behavior in BaTiO{sub 3} perovskite

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, G., E-mail: memodin@yahoo.com [Departamento de Física, CINVESTAV-IPN, A.P. 14-740, México DF 07360, México (Mexico); Escuela Superior de Física y Matemáticas del Instituto Politécnico Nacional, U.P.A.L.M, Edificio 9, Av. Instituto Politécnico Nacional S/N, San Pedro Zacatenco, México DF 07738, México (Mexico); Conde-Gallardo, A. [Departamento de Física, CINVESTAV-IPN, A.P. 14-740, México DF 07360, México (Mexico); Montiel, H. [Centro de Ciencias Aplicadas y Desarrollo Tecnológico de la Universidad Nacional Autónoma de México, Cd. Universitaria, A.P. 70-186, México DF 04510, México (Mexico); Zamorano, R. [Escuela Superior de Física y Matemáticas del Instituto Politécnico Nacional, U.P.A.L.M, Edificio 9, Av. Instituto Politécnico Nacional S/N, San Pedro Zacatenco, México DF 07738, México (Mexico)

    2016-03-01

    A ferromagnetic behavior at room temperature is detected in micro-, submicro- and nano-powders of BaTiO{sub 3} perovskite by means of magnetization measurements, where the magnetic response is originated of different sources, depending on nature of the sample. For BaTiO{sub 3} micropowders is associated with the presence of a magnetic impurity, while for submicro- and nano-powders of BaTiO{sub 3} perovskite, the ferromagnetism is due to magnetic moments arising from the oxygen vacancies on the particles surface. We carry out an additional experimental confirmation of our asseverations by means of the electron paramagnetic resonance (EPR) and the low-field microwave absorption (LFMA), at X-band (8.8–9.8 GHz) and 300 K, indicating the presence of a magnetic impurity in BaTiO{sub 3} micropowders and the existence of oxygen vacancies in BaTiO{sub 3} nanopowders. - Highlights: • Ferromagnetism at 300 K is detected in diverse powders of BaTiO{sub 3} perovskite. • EPR and LFMA techniques are used to investigate the origin of this ferromagnetism. • We discuss on presence of a magnetic impurity and oxygen vacancies in these powders.

  12. Synthesis, magnetic and dielectric characterization of nanocrystalline solid solutions of In{sub 2−x}Ni{sub x}O{sub 3} (x = 0.05, 0.10 and 0.15)

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Tokeer, E-mail: tahmad3@jmi.ac.in [Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025 (India); Khatoon, Sarvari [Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025 (India); Coolahan, Kelsey [Department of Physics and Astronomy, Rowan University, 201 Mullica Hill Road, Glassboro, NJ 08028 (United States)

    2013-09-01

    Graphical abstract: Monophasic and crystalline In{sub 2−x}Ni{sub x}O{sub 3} nanoparticles of size 8–15 nm have been synthesized solvothermally and showed red shift in energy band gap which decreases on increasing Ni{sup 2+} concentration in In{sub 2}O{sub 3} host lattice. - Highlights: • Monophasic Ni-doped In{sub 2}O{sub 3} nanoparticles by solvothermal method for first time. • Plausible reaction mechanism using thermogravimetric analysis. • High surface area with small particle size obtained. • Solid solutions exhibit paramagnetism with very weak antiferromagnetic interactions. - Abstract: In{sub 2−x}Ni{sub x}O{sub 3} (x = 0.05, 0.10 and 0.15) nanoparticles were successfully synthesized by solvothermal method by the thermal decomposition of oxalate precursor at 450 °C for the first time. X-ray diffraction studies showed the formation of highly crystalline and monophasic cubic structure of In{sub 2}O{sub 3} which is attributed to the formation of solid solution. These nanoparticles show good optical transmittance in the visible region. Optical measurements showed an energy band gap which decreases with increasing Ni concentration. The grain size decreases from 15 nm to 8 nm and surface area increases from 90 to 254 m{sup 2} g{sup −1} on increasing the Ni concentration. High dielectric constant and dielectric loss has been obtained which indicates the conducting nature of these solid solutions. Magnetic measurements showed that the samples are strong paramagnetic in nature with very weak antiferromagnetic interactions. No evidence of ferromagnetism is observed for these solid solutions at room temperature.

  13. Aerosol fluxes and particle growth above managed grassland

    Directory of Open Access Journals (Sweden)

    E. Nemitz

    2009-08-01

    Full Text Available Particle deposition velocities (11–3000 nm diameter measured above grassland by eddy covariance during the EU GRAMINAE experiment in June 2000 averaged 0.24 and 0.03 mm s−1 to long (0.75 m and short (0.07 m grass, respectively. After fertilisation with 108 kg N ha−1 as calcium ammonium nitrate, sustained apparent upward fluxes of particles were observed. Analysis of concentrations and fluxes of potential precursor gases, including NH<sub>3, HNO<sub>3, HCl and selected VOCs, shows that condensation of HNO<sub>3 and NH<sub>3 on the surface of existing particles is responsible for this effect. A novel approach is developed to derive particle growth rates at the field scale, from a combination of measurements of vertical fluxes and particle size-distributions. For the first 9 days after fertilization, growth rates of 11 nm particles of 7.04 nm hr−1 and 1.68 nm hr−1 were derived for day and night-time conditions, respectively. This implies total NH4NO<sub>3 production rates of 1.11 and 0.44 μg m−3 h−1, respectively. The effect translates into a small error in measured ammonia fluxes (0.06% day, 0.56% night and a large error in NH4+ and NO<sub>3 aerosol fluxes of 3.6% and 10%, respectively. By converting rapidly exchanged NH<sub>3 and HNO<sub>3 into slowly depositing NH4NO<sub>3, the reaction modifies the total N budget, though this effect is small (<1% for the 10 days following fertilization, as NH<sub>3 emission dominates the net flux. It is estimated that 3.8% of the fertilizer N was volatilised as NH<sub>3, of which 0.05% re-condensed to form NH4NO<sub>3 particles within the lowest 2 m of the surface layer. This surface induced process would at least scale up to a global NH4NO<sub>3 formation of ca. 0.21 kt N yr

  14. Stability of 8-hydroxyquinoline aluminum films encapsulated by a single Al{sub 2}O{sub 3} barrier deposited by low temperature atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Maindron, Tony, E-mail: tony.maindron@cea.fr [CEA-LETI, MINATEC Campus, LETI/DOPT/SCOOP/Laboratoire des Composants pour la Visualisation, 17 rue des Martyrs, F-38054 Grenoble Cedex 9 (France); Simon, Jean-Yves; Viasnoff, Emilie [CEA-LETI, MINATEC Campus, LETI/DOPT/SCOOP/Laboratoire des Composants pour la Visualisation, 17 rue des Martyrs, F-38054 Grenoble Cedex 9 (France); Lafond, Dominique [CEA-LETI, MINATEC Campus, LETI/DTSI/SCMC/, 17 rue des Martyrs, F-38054 Grenoble Cedex 9 (France)

    2012-09-30

    100 nm thick 8-AlQ{sub 3} films deposited onto silicon wafers have been encapsulated by mean of low temperature atomic layer deposition of Al{sub 2}O{sub 3} (20 nm). Investigation of the film evolution under storage test as harsh as 65 Degree-Sign C/85% RH has been investigated up to {approx} 1000 h and no severe degradation could be noticed. The results have been compared to raw AlQ{sub 3} films which deteriorate far faster in the same conditions. For that purpose, fluorescence measurements and atomic force microscopy have been used to monitor the film evolution while transmission electron microscopy has been used to image the interface between AlQ{sub 3} and Al{sub 2}O{sub 3}. This concept of bilayer AlQ{sub 3}/Al{sub 2}O{sub 3} barrier films has finally been tested as an encapsulation barrier onto an organic light-emitting diode. - Highlights: Black-Right-Pointing-Pointer Thin Al{sub 2}O{sub 3} films have been deposited by atomic layer deposition onto organic films. Black-Right-Pointing-Pointer AlQ{sub 3}/Al{sub 2}O{sub 3}-encapsulated organic light-emitting diodes show long-term stability. Black-Right-Pointing-Pointer Unencapsulated reference AlQ{sub 3} films degrade much faster.

  15. LaTiO{sub 3}/KTaO{sub 3} interfaces: A new two-dimensional electron gas system

    Energy Technology Data Exchange (ETDEWEB)

    Zou, K.; Ismail-Beigi, Sohrab; Walker, F. J.; Ahn, C. H. [Department of Applied Physics and Center for Research on Interface Structures and Phenomena (CRISP), Yale University, New Haven, Connecticut 06520 (United States); Kisslinger, Kim; Su, Dong [Brookhaven National Laboratory, Center for Functional Nanomaterials, Upton, New York 11973 (United States); Shen, Xuan [Brookhaven National Laboratory, Center for Functional Nanomaterials, Upton, New York 11973 (United States); National Laboratory of Solid State Microstructures and Department of Materials Science and Engineering, Nanjing University, Nanjing 210093 (China)

    2015-03-01

    We report a new 2D electron gas (2DEG) system at the interface between a Mott insulator, LaTiO{sub 3}, and a band insulator, KTaO{sub 3}. For LaTiO{sub 3}/KTaO{sub 3} interfaces, we observe metallic conduction from 2 K to 300 K. One serious technological limitation of SrTiO{sub 3}-based conducting oxide interfaces for electronics applications is the relatively low carrier mobility (0.5-10 cm{sup 2}/V s) of SrTiO{sub 3} at room temperature. By using KTaO{sub 3}, we achieve mobilities in LaTiO{sub 3}/KTaO{sub 3} interfaces as high as 21 cm{sup 2}/V s at room temperature, over a factor of 3 higher than observed in doped bulk SrTiO{sub 3}. By density functional theory, we attribute the higher mobility in KTaO{sub 3} 2DEGs to the smaller effective mass for electrons in KTaO{sub 3}.

  16. The Cu{sub 2}FeTi{sub 3}S{sub 8} and Cu{sub 2}FeZr{sub 3}S{sub 8} compounds: Crystal structure and electroanalytical application

    Energy Technology Data Exchange (ETDEWEB)

    Kormosh, Zh., E-mail: kormosh@univer.lutsk.ua [Department of Analytical Chemistry and Eco-technology, Volyn National University, 13 Voli Ave, 43025 Lutsk (Ukraine); Fedorchuk, A. [Department of Inorganic and Organic Chemistry, Lviv National University of Veterinary Medicine and Biotechnologies, 50 Pekarska St., 79010 Lviv (Ukraine); Wojciechowski, K. [Department of Inorganic Chemistry, Faculty of Materials Science and Ceramics, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Cracow (Poland); Tataryn, N. [Department of Analytical Chemistry and Eco-technology, Volyn National University, 13 Voli Ave, 43025 Lutsk (Ukraine); Parasyuk, O. [Department of Inorganic and Physical Chemistry, Volyn National University, 13 Voli Ave, 43025 Lutsk (Ukraine)

    2011-04-08

    The Cu{sub 2}FeTi{sub 3}S{sub 8} and Cu{sub 2}FeZr{sub 3}S{sub 8} compounds were produced by solid-state synthesis. The crystal structure of the quaternary phases was investigated by X-ray powder method. The compounds are described in the thiospinel structure (space group Fd3-bar m) with the unit cell parameters a = 1.00099(1) nm (Cu{sub 2}FeTi{sub 3}S{sub 8}) and a = 1.03837(2) nm (Cu{sub 2}FeZr{sub 3}S{sub 8}). The atomic parameters were calculated in the isotropic approximation (R{sub I} = 0.0496 and R{sub I} = 0.0422 for Cu{sub 2}FeTi{sub 3}S{sub 8} and Cu{sub 2}FeZr{sub 3}S{sub 8}, respectively). Iron(III)-selective electrodes were prepared using the chalcogenide compounds Cu{sub 2}FeTi{sub 3}S{sub 8} and Cu{sub 2}FeZr{sub 3}S{sub 8}. The electrode function slopes are 52.7 mV/pC for Cu{sub 2}FeTi{sub 3}S{sub 8} and 66.2 mV/pC for Cu{sub 2}FeZr{sub 3}S{sub 8}, the detection limits are 1 x 10{sup -5} M and 2 x 10{sup -5} M respectively. The prepared electrochemical sensors are not sensitive to Cd{sup 2+}, Zn{sup 2+}, Mn{sup 2+}, Ni{sup 2+}, Co{sup 2+}, Mg{sup 2+}, Cr{sup 3+}, and Fe{sup 2+} ions, and were tested in the potentiometric titration of Fe(III) with EDTA solution.

  17. Silicon MIS diodes with Cr{sub 2}O{sub 3} nanofilm: Optical, morphological/structural and electronic transport properties

    Energy Technology Data Exchange (ETDEWEB)

    Erdogan, Ibrahim Y. [Bingoel University, Faculty of Sciences and Arts, Department of Chemistry, 12000- Bingoel (Turkey); Guellue, O., E-mail: omergullu@gmail.com [Batman University, Faculty of Sciences and Arts, Department of Physics, 72060- Batman (Turkey)

    2010-04-15

    In this work we report the optical, morphological and structural characterization and diode application of Cr{sub 2}O{sub 3} nanofilms grown on p-Si substrates by spin coating and annealing process. X-ray diffraction (XRD), non-contact mode atomic force microscopy (NC-AFM), ultraviolet-visible (UV-vis) spectroscopy and photoluminescence (PL) spectroscopy were used for characterization of nanofilms. For Cr{sub 2}O{sub 3} nanofilms, the average particle size determined from XRD and NC-AFM measurements was approximately 70 nm. Structure analyses of nanofilms demonstrate that the single phase Cr{sub 2}O{sub 3} on silicon substrate is of high a crystalline structure with a dominant in hexagonal (1 1 0) orientation. The morphologic analysis of the films indicates that the films formed from hexagonal nanoparticles are with low roughness and uniform. UV-vis absorption measurements indicate that the band gap of the Cr{sub 2}O{sub 3} film is 3.08 eV. The PL measurement shows that the Cr{sub 2}O{sub 3} nanofilm has a strong and narrow ultraviolet emission, which facilitates potential applications in future photoelectric nanodevices. Au/Cr{sub 2}O{sub 3}/p-Si metal/interlayer/semiconductor (MIS) diodes were fabricated for investigation of the electronic properties such as current-voltage and capacitance-voltage. Ideality factor and barrier height for Au//Cr{sub 2}O{sub 3}/p-Si diode were calculated as 2.15 eV and 0.74 eV, respectively. Also, interfacial state properties of the MIS diode were determined. The interface-state density of the MIS diode was found to vary from 2.90 x 10{sup 13} eV{sup -1} cm{sup -2} to 8.45 x 10{sup 12} eV{sup -1} cm{sup -2}.

  18. Magnetic and superconductivity studies on (In{sub 1−x}Fe{sub x}){sub 2}O{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sai Krishna, N. [Thin Films Laboratory, School of Advanced Sciences, VIT University, Vellore 632 014, Tamil Nadu (India); Kaleemulla, S., E-mail: skaleemulla@gmail.com [Thin Films Laboratory, School of Advanced Sciences, VIT University, Vellore 632 014, Tamil Nadu (India); Amarendra, G. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu (India); UGC-DAE-CSR, Kalpakkam Node, Kokilamedu 603 104, Tamil Nadu (India); Madhusudhana Rao, N.; Krishnamoorthi, C.; Rigana Begam, M. [Thin Films Laboratory, School of Advanced Sciences, VIT University, Vellore 632 014, Tamil Nadu (India); Omkaram, I. [Department of Electronics and Radio Engineering, Kyung Hee University, Yongin-si Gyeonggi-do 446-701 (Korea, Republic of); Sreekantha Reddy, D. [Department of Physics and Sungkyunkwan Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2015-07-15

    Highlights: • Fe doped In{sub 2}O{sub 3} thin films deposited using electron beam evaporation technique. • Characterization of the samples using XRD, SEM, EDAX, AES, Raman spectroscopy, FT-IR, VSM and magnetoresistance. • All Fe doped In{sub 2}O{sub 3} thin films exhibited the cubic structure of In{sub 2}O{sub 3}. • Pure and Fe doped In{sub 2}O{sub 3} samples exhibited room temperature ferromagnetism and superconductivity at 2 K. - Abstract: Magnetic, magnetoresistivity and superconductivity studies were carried out on (In{sub 1−x}Fe{sub x}){sub 2}O{sub 3} (x = 0.00, 0.03, 0.05 and 0.07) thin films (2D structures) grown on glass substrate by electron beam evaporation technique at 350 °C. The films have an average size of 120 nm particles. All the samples shown soft ferromagnetic hysteresis loops at room temperature and saturation magnetization increased with iron dopant concentration. Observed magnetization could be best interpreted by F-center mediated magnetic exchange interaction in the samples. Temperature dependent resistivity of the sample (x = 0.00 and 0.07) showed metallic behavior down to very low temperatures and superconductivity at 2 K for undoped In{sub 2}O{sub 3} whereas the In{sub 1.86}Fe{sub 0.14}O{sub 3} sample shows superconductivity below 2 K in the absence of magnetic fields. The reduction in transition temperature was attributed to increase electrical disorder with iron doping. Both samples showed positive magnetoresistivity (MR) in superconducting state due to increase of resistivity resulting from breaking of superconducting Cooper pairs upon application of magnetic field. In addition, both the samples show feeble negative MR in normal electrical state. The observed MR in normal state is not due to spin polarized tunneling instead it is due to suppression of scattering of charge carrier by single occupied localized states.

  19. Properties of the (Sm sub 0 sub . sub 3 sub 3 Eu sub 0 sub . sub 3 sub 3 Gd sub 0 sub . sub 3 sub 3)Ba sub 2 Cu sub 3 O sub y superconductor prepared by different processes in air

    CERN Document Server

    Giovannelli, F; Monot-Laffez, I

    2003-01-01

    Bars and pellets of the (Sm sub 0 sub . sub 3 sub 3 Eu sub 0 sub . sub 3 sub 3 Gd sub 0 sub . sub 3 sub 3)Ba sub 2 Cu sub 3 O sub x superconductor were processed in air, using the floating zone method and the top-seeded melt-textured growth method, respectively. The samples were prepared using different experimental conditions, i.e. maximal processing temperature, translation rate or cooling rate. Their physical properties and their microstructure were studied. All the samples exhibit a satisfying superconducting transition whereas the critical current density greatly depends on the processing parameters. The sample prepared by the floating zone method at 1070 deg C with a translation rate of 2 mm h sup - sup 1 exhibits a very high J sub c value of 70000 A cm sup - sup 2 in the self-field and more than 30000 A cm sup - sup 2 at 1.7 T. The pellet processed at 1080 deg C with a cooling rate of 2 deg C h sup - sup 1 has a high J sub c reaching about 56000 A cm sup - sup 2 in the self-field and more than 32000 A ...

  20. Static and dynamic magnetic properties of CoPt{sub 3}. Nanoparticles in comparison with bulk matter; Statische und dynamische magnetische Eigenschaften von CoPt{sub 3}. Nanopartikel im Vergleich zum Volumenmaterial

    Energy Technology Data Exchange (ETDEWEB)

    Raeder, C.

    2006-09-22

    In this work the structural and magnetic characteristics of CoPt{sub 3}-particles are examined. In particular the determination of the g-factor is of interest as well as the damping behavior of the magnetization vector under influence of a microwave radiation. Moreover the magnetic anisotropy energy density of individual particles is covered by the presented thesis. The particles exist in the chemically disordered phase. They are monocrystalline and monodisperse with a mean diameter of d=4.04 nm and a width of the size distribution of {sigma}=0.15, as determined by transmission electron microscopy. Moreover the particles are embedded into a polymer with high dilution (0.08 vol%). To compare the results for the particles CoPt{sub 3} films and bulk-material are prepared and examined with the same procedure. X-ray diffraction (XRD) shows that all three sample systems are an alloy and do not appear as cobalt clusters embedded in platinum. The lattice constant of the particles is increased by 0.5% in comparison to the bulk material (a{sub NP}=0.388{+-}0.003 nm). The evaluation of the peak widths of the XRD experiments exhibit a crystalline size of 95.5{+-}6.5 nm of the films and 48.5{+-}6.5 nm of the bulk material. The evaluation of the relative intensities of (111)- and (200)-peaks points the fact that both the film and the particles preferentially grow in the (111)-direction. The films are polycrystalline in the film-plane. From magnetic resonance measurements the g-factor and the damping constant {alpha} is extracted. The measurement shows that both the g-factor (about 2%) and the damping-constant {alpha} (about 125%) is increased in comparison to the film, and/or bulk material. For the films M{sub eff} is determined from angle-dependent resonance-field measurements. From the temperature dependence of the resonance field the magnetic anisotropy is determined. Because of the fact that the measurements could be done only to a minimum of 50 K the value of the anisotropy

  1. Synthesis, crystal structure and properties of a new lead fluoride borate, Pb{sub 3}OBO{sub 3}F

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Wenwu [Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, 40-1 South Beijing Road, Urumqi 830011 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Pan, Shilie, E-mail: slpan@ms.xjb.ac.cn [Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, 40-1 South Beijing Road, Urumqi 830011 (China); Dong, Xiaoyu [Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, 40-1 South Beijing Road, Urumqi 830011 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Li, Junjie; Tian, Xuelin; Fan, Xiaoyun [Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, 40-1 South Beijing Road, Urumqi 830011 (China); Chen, Zhaohui [Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, 40-1 South Beijing Road, Urumqi 830011 (China); Physical and Chemical Detecting Center, Xinjiang University, Urumqi 830046 (China); Zhang, Fangfang [Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, 40-1 South Beijing Road, Urumqi 830011 (China)

    2012-04-15

    Graphical abstract: The structure of Pb{sub 3}OBO{sub 3}F consists of two distortional Pb-centered tetrahedra and BO{sub 3} triangles which are all symmetrical with each other respectively in the gestalt structure to the extent that the Pb{sub 3}OBO{sub 3}F compound crystallizes in the symmetrical space group. Highlights: Black-Right-Pointing-Pointer Pb{sub 3}OBO{sub 3}F has been grown from PbO-PbF{sub 2}-B{sub 2}O{sub 3} system for the first time. Black-Right-Pointing-Pointer It crystallizes in the orthorhombic system, space group Pbcm. Black-Right-Pointing-Pointer Pb{sub 3}OBO{sub 3}F consists of Pb(1)O{sub 3}F tetrahedra, Pb(2)O{sub 4} tetrahedra and BO{sub 3} triangles. -- Abstract: A new compound, Pb{sub 3}OBO{sub 3}F, has been grown by the high temperature solution method from the PbO-PbF{sub 2}-B{sub 2}O{sub 3} system. It crystallizes in the orthorhombic system, space group Pbcm with unit-cell parameters a = 7.6313(14) Angstrom-Sign , b = 6.5229(12) Angstrom-Sign , c = 11.906(2) Angstrom-Sign , Z = 4, volume = 592.66(19) Angstrom-Sign {sup 3}. The structure of the compound is solved by the direct methods and refined to R{sub 1} = 0.0528 and wR{sub 2} = 0.1400. Pb{sub 3}OBO{sub 3}F consists of Pb(1)O{sub 3}F tetrahedra, Pb(2)O{sub 4} tetrahedra and BO{sub 3} triangles which build up the symmetrical chains extended along the c-axis. The powder X-ray diffraction pattern of the Pb{sub 3}OBO{sub 3}F has been measured. Functional groups presented in the sample were identified by Fourier transform infrared spectrum.

  2. Effects of Al{sub 2}O{sub 3} phase and Cl component on dehydrogenation of propane

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jie; Liu, Changcheng; Ma, Aizeng; Rong, Junfeng; Da, Zhijian, E-mail: dazhijianripp@163.com; Zheng, Aiguo; Qin, Ling

    2016-04-15

    Graphical abstract: - Highlights: • Comparative study of Al{sub 2}O{sub 3} phase on dehydrogenation of propane was implemented. • Pore structures and acid properties of Pt-Al{sub 2}O{sub 3} are correlated to the activities. • Pt-θ-Al{sub 2}O{sub 3} with abundant Cl content shows the highest activity and stability. - Abstract: The effects of two Al{sub 2}O{sub 3} phases, γ- and θ-Al{sub 2}O{sub 3}, and Cl component on the performances of Pt-Al{sub 2}O{sub 3} catalysts in the dehydrogenation of propane were investigated in this work. The catalysts were systematically characterized by various techniques, such as scanning transmission electron microscopy (STEM), temperature-programmed desorption with ammonia as probe molecules (NH{sub 3}-TPD) and temperature-programmed oxidation (TPO). The characterizations and catalytic results show that: (i) the pore structures and acid properties of the two Al{sub 2}O{sub 3} phases can change the quantity, location and property of the carbon deposition, (ii) the existence of Cl plays a significant role on the agglomeration of Pt particles and carbon deposition, which further influence the catalytic performances of Pt-Al{sub 2}O{sub 3} catalysts with different support phases for propane dehydrogenation.

  3. Synthesis and photocatalytic property of multilayered Co{sub 3}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Dong En, E-mail: zdewxm@aliyun.com [Department of Chemical Engineering, Huaihai Institute of Technology, Lianyungang 222005 (China); Jiangsu Marine Resources Develepment Research Insititute, Lianyungang 222005 (China); School of Chemistry and Chemical Engineering, Nanjing University, 22 Hankou Road, Nanjing 210093 (China); Ren, Li Zheng; Hao, Xiao Yun; Pan, Bin Bin; Wang, Ming Yan; Ma, Juan Juan; Li, Feng [Department of Chemical Engineering, Huaihai Institute of Technology, Lianyungang 222005 (China); Li, Shu An [Jiangsu Marine Resources Develepment Research Insititute, Lianyungang 222005 (China); Tong, Zhi Wei [Department of Chemical Engineering, Huaihai Institute of Technology, Lianyungang 222005 (China)

    2015-11-15

    Highlights: • Multilayered Co{sub 3}O{sub 4} particles are synthesized from decomposition of multilayered Co{sub 2}(CO{sub 3})(OH){sub 2}. • The influences of solvent and probable growth mechanism are discussed. • The Co{sub 3}O{sub 4} particles exhibit good photocatalytic activity on degradation of MV. - Abstract: Co{sub 3}O{sub 4} multilayered structures were successfully synthesized by a facile poly (ethylene glycol 20000) (PEG-20000) assisted hydrothermal technique in combination with calcination method. The final Co{sub 3}O{sub 4} multilayered structures inherited perfectly the morphology of the preliminarily hydrothermal products. Experimental results obtained from the different growth stages demonstrate that the as-prepared precursor exhibit an interesting time-dependent evolution of building blocks, from urchin to multilayer. The possible formation mechanism for the hierarchical structures with various architectures is presented on account of the self-assembled growth induced by Ostwald ripening. Because of the unique structured composed of slices, the photocatalytic activity of the products was examined by measuring the photodecolourisation of methyl violet solution with ultraviolet radiation. The result shows that our products have a good photocatalytic activity.

  4. Solvothermal synthesis of graphene-Sb{sub 2}S{sub 3} composite and the degradation activity under visible light

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Wenguang; Chang, Jiuli; Wu, Dapeng [College of Chemistry and Chemical Engineering, Henan Normal University, Henan, Xinxiang 453007 (China); Gao, Zhiyong, E-mail: zygao512@163.com [College of Chemistry and Chemical Engineering, Henan Normal University, Henan, Xinxiang 453007 (China); Duan, Xiaoli [Engineering Technology Research Center of Motive Power and Key Materials, Henan, 453007 (China); Xu, Fang [College of Chemistry and Chemical Engineering, Henan Normal University, Henan, Xinxiang 453007 (China); Engineering Technology Research Center of Motive Power and Key Materials, Henan, 453007 (China); Jiang, Kai, E-mail: jiangkai6898@126.com [College of Chemistry and Chemical Engineering, Henan Normal University, Henan, Xinxiang 453007 (China); Engineering Technology Research Center of Motive Power and Key Materials, Henan, 453007 (China)

    2013-02-15

    Graphical abstract: Display Omitted Highlights: ► Graphene-Sb{sub 2}S{sub 3} composites were synthesized through a facile solvothermal method. ► Hydroxyl radicals are the main species responsible for the photodegradation activity. ► Graphene-Sb{sub 2}S{sub 3} demonstrated dramatically improved visible light degradation activity. -- Abstract: Novel graphene-Sb{sub 2}S{sub 3} (G-Sb{sub 2}S{sub 3}) composites were synthesized via a facile solvothermal method with graphene oxide (GO), SbCl{sub 3} and thiourea as the reactants. GO played an important role in controlling the size and the distribution of the formed Sb{sub 2}S{sub 3} nanoparticles on the graphene sheets with different density. Due to the negative surface charge, smaller Sb{sub 2}S{sub 3} particles size and efficient electrons transfer from Sb{sub 2}S{sub 3} to graphene, the composites demonstrated improved photodegradation activity on rhodamine B (RhB). Among these composites, the product G-Sb{sub 2}S{sub 3} 0.1, which was synthesized with the GO concentration of 0.1 mg/mL, exhibited the highest photodegradation activity owing to the considerable density of Sb{sub 2}S{sub 3} nanoparticles onto graphene sheet free of aggregation. Hydroxyl radicals (·OH) derived from conduction band (CB) electrons of Sb{sub 2}S{sub 3} is suggested to be responsible for the photodegradation of RhB. The high visible light degradation activity and the satisfactory cycling stability made the as-prepared G-Sb{sub 2}S{sub 3} 0.1 an applicable photocatalyst.

  5. Surfaces and their effect on the magnetic properties of polycrystalline hollow γ-Mn{sub 2}O{sub 3} and MnO nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Bah, Mohamed A. [Department of Materials Science and Engineering, Newark, DE (United States); Jaffari, G. Hassnain [Department of Physics, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Khan, F.A. [Department of Physics, Bangladesh University of Engineering and Technology, Dhaka 1000 (Bangladesh); Shah, S. Ismat, E-mail: ismat@udel.edu [Department of Materials Science and Engineering, Newark, DE (United States); Department of Physics and Astronomy, Newark, DE (United States)

    2016-07-01

    Graphical abstract: Polycrystalline hollow nanoparticles composed of γ-Mn{sub 2}O{sub 3} and MnO were grown in an inert gas condensation system. Particles where found to range from 15 nm to 30 nm in diameter with different void sizes. Both γ-Mn{sub 2}O{sub 3} and MnO phases were found to exist in a single nanoparticle, and in close proximity. The oxides had different size and random lattice orientations. The morphology of the nanoparticles with the specific oxide is believed to be the leading cause for the observed high coercivity and exchange bias. - Highlights: • Polycrystalline hollow nanoparticles composed of γ-Mn{sub 2}O{sub 3} (ferrimagnetic(FiM)) and MnO (antiferromagnetic(AFM)) crystallites. • γ-Mn{sub 2}O{sub 3} and MnO co-exist in a single nanoparticles. • FC loops exhibited noticeably larger coercivity compared to the ZFC loops. • Compared to the core/shell counter parts, large coercivity and exchange bias, up to 11 kOe and 7 kOe, respectively, were observed at low temperature. • Strong coupling between the FiM and AFM phases. • Large horizontal and vertical shifts. - Abstract: Manganese oxide nanoparticles were prepared in an inert gas condensation system. X-ray Diffraction (XRD) studies revealed presence of multiple manganese oxide phases while high resolution transmission electron microscopy (HRTEM) showed polycrystalline hollow nanoparticle morphology. The additional inner surface of the hollow nanoparticle directly affect the magnetic properties of these particles. Combined physical structure, electronic structure and magnetic susceptibility analyses led to the conclusion that the prepared nanoparticles are polycrystalline and composed of γ-Mn{sub 2}O{sub 3} and MnO crystallites. Magnetic study found a sharp peak around 38 K with no frequency dependence in the AC susceptibility measurement. Large coercivity (H{sub C}) and exchange bias (H{sub EB}) fields, up to 11 kOe and 7 kOe, respectively, were observed below the order

  6. Effect of ferrofluid concentration on electrical and magnetic properties of the Fe{sub 3}O{sub 4}/PANI nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Alam, Javed [Materials Research Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025 (India); Riaz, Ufana [Materials Research Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025 (India); Ahmad, Sharif [Materials Research Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025 (India)]. E-mail: sharifahmad_jmi@yahoo.co.in

    2007-07-15

    Magnetic nanocomposites can be controlled and tailored to provide the desired mechanical, physical, chemical, and biomedical properties depending on the final applications. The coating of ferrite nanoparticles with polymers affords the possibility of minimizing agglomeration in large-scale commercial synthesis of nanocomposite materials. The process of coating not only provides effective encapsulation of individual nanoparticles, but also controls the growth in size, thus, yielding a better overall size distribution. In this paper, in-situ polymerization of aniline was carried out in different concentration of the ferrofluid with the aim to obtain agglomerate free nanocomposites. The role of the ferrite concentration was investigated by the spectral, morphological, conductivity, and magnetic properties of Fe{sub 3}O{sub 4}/polyaniline (PANI) nanocomposites. XRD revealed the presence of spinel phase of Fe{sub 3}O{sub 4} and the particle size was calculated to be 14.3 nm. Spectral analysis confirmed the formation of PANI encapsulated Fe{sub 3}O{sub 4} nanocomposite. Conductivity of the nanocomposites was found to be in the range of 0.001-0.003 S/cm. Higher saturation magnetization of 3.2 emu/g was observed at 300 K, revealing a super paramagnetic behavior of this nanocomposite.

  7. Microstructure evolution and electrical characterization of Lanthanum doped Barium Titanate (BaTiO{sub 3}) ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Billah, Masum, E-mail: masum.buet09@gmail.com; Ahmed, A., E-mail: jhinukbuetmme@gmail.com; Rahman, Md. Miftaur, E-mail: miftaurrahman@mme.buet.ac.bd [Department of Materials & Metallurgical Engineering, Bangladesh University of Engineering and Technology, Dhaka-1000 (Bangladesh); Mahbub, Rubbayat, E-mail: rubayyatm@gce.buet.ac.bd [Department of Glass and Ceramic Engineering, Bangladesh University of Engineering and Technology, Dhaka-1000 (Bangladesh); Gafur, M. A., E-mail: d-r-magafur@bcsir.gov.bd [Bangladesh Council of Scientific & Industrial Research (BCSIR), Dhaka-1205 (Bangladesh); Bashar, M. Shahriar, E-mail: bashar@agni.com [Institute of Fuel Research & Development, Bangladesh Council of Scientific & Industrial Research (BCSIR), Dhaka-1205 (Bangladesh)

    2016-07-12

    In the current work, we investigated the structural and dielectric properties of Lanthanum oxide (La{sub 2}O{sub 3}) doped Barium Titanate (BaTiO{sub 3}) ceramics and established a correlation between them. Solid state sintering method was used to dope BaTiO{sub 3} with 0.3, 0.5 and 0.7 mole% La{sub 2}O{sub 3} under different sintering parameters. The raw materials used were La{sub 2}O{sub 3} nano powder of ~80 nm grain size and 99.995% purity and BaTiO{sub 3} nano powder of 100 nm grain size and 99.99% purity. Grain size distribution and morphology of fracture surface of sintered pellets were examined by Field Emission Scanning Electron Microscope and X-Ray Diffraction analysis was conducted to confirm the formation of desired crystal structure. The research result reveal that grain size and electrical properties of BaTiO{sub 3} ceramic significantly enhanced for small amount of doping (up to 0.5 mole% La{sub 2}O{sub 3}) and then decreased with increasing doping concentration. Desired grain growth (0.80-1.3 µm) and high densification (<90% theoretical density) were found by proper combination of temperature, sintering parameters and doping concentration. We found the resultant stable value of dielectric constant was 10000-12000 at 100-300 Hz in the temperature range of 30°-50° C for 0.5 mole% La{sub 2}O{sub 3} with corresponding shift of curie temperature around 30° C. So overall this research showed that proper La{sup 3+} concentration can control the grain size, increase density, lower curie temperature and hence significantly improve the electrical properties of BaTiO{sub 3} ceramics.

  8. Carbon-coated Fe{sub 2}O{sub 3} nanocrystals with enhanced lithium storage capability

    Energy Technology Data Exchange (ETDEWEB)

    Chai, Xiaohan; Shi, Chunsheng [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin 300072 (China); Liu, Enzuo [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin 300072 (China); Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072 (China); Li, Jiajun [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin 300072 (China); Zhao, Naiqin [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin 300072 (China); Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072 (China); Key Laboratory of Advanced Ceramics and Machining Technology, Ministry of Education, Tianjin University, Tianjin 300072 (China); He, Chunnian, E-mail: cnhe08@tju.edu.cn [School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University, Tianjin 300072 (China); Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072 (China); Key Laboratory of Advanced Ceramics and Machining Technology, Ministry of Education, Tianjin University, Tianjin 300072 (China)

    2015-08-30

    Highlights: • Fe{sub 2}O{sub 3} nanocrystals embedded in interconnected carbon nanospheres were synthesized. • The Fe{sub 2}O{sub 3}@C nanospheres deliver high reversible lithium storage capacity. • The interconnected carbon matrix can buffer the volume expansion of Fe{sub 2}O{sub 3.} - Abstract: Homogeneous and highly crystalline Fe{sub 2}O{sub 3} nanocrystals (∼8 nm) embedded in interconnected carbon nanospheres (∼50 nm) (Fe{sub 2}O{sub 3}@C) have been fabricated by one-step hydrothermal reaction followed by annealing with Ar. When used as the anode materials for lithium-ion batteries, the Fe{sub 2}O{sub 3}@C nanospheres with 55.24 wt% Fe{sub 2}O{sub 3} deliver high reversible lithium storage capacity (826 mAh/g at 0.1 A/g after 20 cycles), high Coulombic efficiency (∼99%) and good cycling stability, which are much better than that of commercial Fe{sub 2}O{sub 3} nanoparticles. These excellent electrochemical performances could be attributed to the robust and high-conducting interconnected carbon nanospheres embedded with a mass of small Fe{sub 2}O{sub 3} nanocrystals, which not only can offer large quantity of accessible active sites for lithium-ion reaction as well as good conductivity and short diffusion length for electron and ion transport, but also can effectively suppress the aggregation and buffer the volume expansion of Fe{sub 2}O{sub 3} nanocrystals during the repeated lithiation and delithiation processes.

  9. Synthesis and characterization of large WO{sub 3} sheets synthesized by resistive heating method

    Energy Technology Data Exchange (ETDEWEB)

    Filippo, Emanuela, E-mail: emanuela.filippo@unisalento.it [Department of Engineering for Innovation, University of Salento, Monteroni Street, Lecce I-73100 Italy (Italy); Tepore, Marco [Department of Engineering for Innovation, University of Salento, Monteroni Street, Lecce I-73100 Italy (Italy); Baldassarre, Francesca [Department of Cultural Heritage, University of Salento, Lecce I-73100 Italy (Italy); Quarta, Gianluca; Calcagnile, Lucio [Department of Engineering for Innovation, University of Salento, Monteroni Street, Lecce I-73100 Italy (Italy); Guascito, Maria Rachele [DiSTeBA, University of Salento, Lecce I-73100 Italy (Italy); Tepore, Antonio [Department of Cultural Heritage, University of Salento, Lecce I-73100 Italy (Italy)

    2015-09-01

    A simple, low-cost method is presented to grow tungsten oxide large sheets simply by resistively heating a pure tungsten filament under air/water vapor flow. The obtained structures were studied using scanning and transmission electron microscopy, selected area diffraction, X Ray diffraction, Raman and X-ray photoelectron spectroscopy, photoluminescence and zeta potential measurements. SEM observations revealed that sheets formed by broadening of the wires/belts over longer growth period. Photoluminescence measurements showed that tungsten oxide sheets had an intense visible emission band. - Highlights: • WO{sub 3} large sheets were prepared by resistively heating a W filament. • WO{sub 3} sheets were carefully characterized. • Formation mechanism of sheets was studied. • WO{sub 3} sheets had an intense visible emission band at 462 nm.

  10. Structural study, photoluminescence, and photocatalytic activity of semiconducting BaZrO{sub 3}:Bi nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Borja-Urby, R. [Grupo de Espectroscopia de Materiales Avanzados y Nanoestructurados (EMANA), Centro de Investigaciones en Optica A.C., Leon, Gto 37150 (Mexico); Diaz-Torres, L.A., E-mail: ditlacio@cio.mx [Grupo de Espectroscopia de Materiales Avanzados y Nanoestructurados (EMANA), Centro de Investigaciones en Optica A.C., Leon, Gto 37150 (Mexico); Salas, P. [Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico, A.P. 1-1010, Queretaro 76000 (Mexico); Moctezuma, E. [Facultad de Ciencias Quimicas, Universidad Autonoma de San Luis Potosi, Av. Manuel Nava 6, San Luis Potosi, S.L.P., Mexico 78290 (Mexico); Vega, M. [Centro de Geociencias-UNAM, A.P. 1-1010, Queretaro 76000 (Mexico); Angeles-Chavez, C. [Instituto Mexicano del Petroleo, Ciudad de Mexico, D.F. 07730 (Mexico)

    2011-10-25

    Wide band gap nanocrystalline bismuth doped barium zirconate is synthesized by a facile hydrothermal method at 100 deg. C. The obtained cubic perovskites are characterized by powder X-ray diffraction (XRD), UV-VIS diffuse reflectance spectroscopy, photoluminescence (PL) spectroscopy, and photocatalytic activity. The estimated band gap in the 2.4-4.9 eV range, depending on Bi concentration, suggests nanocrystalline BaZrO{sub 3}:Bi as a useful visible-light activated photocatalyst under excitation wavelengths <800 nm. Displacement of main XRD pattern peaks suggest that bismuth ion mostly substitutes into Zr{sup 4+} sites within the BaZrO{sub 3} host lattice. It is found that BaZrO{sub 3}:Bi decomposes methylene blue (MB) under both UV and visible light irradiation. The photocatalyst efficiency depends strongly on Bi content and induced defects.

  11. Optical and structural characterization of SrZr{sub 0,1}Ti{sub 0,9}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Delgado-Nino, Pilar [Laboratorio de Catalisis Heterogenea, Departamento de Quimica, Facultad de Ciencias, Universidad Nacional de Colombia, Bogota, D.C. (Colombia); Lopez-Rivera, S.A., E-mail: adan@ula.ve [Grupo de Fisica Aplicada, Facultad de Ciencias, Universidad de los Andes, Merida (Venezuela, Bolivarian Republic of); Mestres-Vila, Lourdes; Martinez-Sarrion, Maria Luisa [Departamento de Quimica Inorganica, Facultad de Quimica, Universitat de Barcelona, Barcelona, Espana (Spain); Valencia-Rios, Jesus S. [Laboratorio de Catalisis Heterogenea, Departamento de Quimica, Facultad de Ciencias, Universidad Nacional de Colombia, Bogota, D.C. (Colombia)

    2012-10-15

    In this work, the ceramic compound SrTi{sub 0.90}Zr{sub 0,1}O{sub 3} (SZT) was synthesized by the citrate method. This solid showed a 12 nm crystallite size, reflecting the high degree of crystallinity obtained by this synthesis route. Differential and gravimetric thermal analysis showed that the solid was formed from 520 Degree-Sign C; the chemical composition was determined by ICP-AES4, giving a stoichiometry corresponding to the SrTi{sub 0.90}Zr{sub 0.10}O{sub 3} formula, and proved to be compatible with the X-ray diffraction data, refined by the Rietveld method. The morphology was explored by means of SEM and TEM, finding a homogenous particles distribution, arranged in lumps, susceptible to density changes by sintering between 1000 Degree-Sign C and 1200 Degree-Sign C. The photoluminescence (PL) spectrum shows a band between 470 nm and 520 nm, corresponding to the Ti and Zr ions 3d electronic transition. The SZT crystal structure is tetragonal with space group I4/mcm, number (140). - Highlights: Black-Right-Pointing-Pointer The ceramic nano structured compound SrTi{sub 0.90}Zr{sub 0,1}O{sub 3} was synthesized by the citrate method. Black-Right-Pointing-Pointer Differential and gravimetric thermal analysis showed the right thermodynamical parameters Black-Right-Pointing-Pointer Good agreement between the crystal structure, group theory and the optical properties was obtained. Black-Right-Pointing-Pointer The sized and high crystallinity of the nanoparticules was confirmed by SEM and TEM. Black-Right-Pointing-Pointer Crystal structure is tetragonal with space group I4/mcm was found by X-ray and Rietveld refinement.

  12. Controllable synthesis of Co{sub 3}O{sub 4}/polyethyleneimine-carbon nanotubes nanocomposites for CO and NH{sub 3} gas sensing at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Yufei [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080 (China); Kan, Kan [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080 (China); Institute of Advanced Technology, Heilongjiang Academy of Sciences, Harbin 150000 (China); Song, Wanzhen; Zhang, Guo; Dang, Lifang [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080 (China); Xie, Yu [Department of Materials Chemistry, Nanchang Hangkong University, Nanchang 330063 (China); Shen, Peikang [Department of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Li, Li, E-mail: llwjjhlju@sina.cn [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080 (China); Key Laboratory of Chemical Engineering Process & Technology for High-efficiency Conversion, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080 (China); Shi, Keying, E-mail: shikeying2008@163.com [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080 (China)

    2015-08-05

    Graphical abstract: Co{sub 3}O{sub 4}/polyethyleneimine-carbon nanotubes composites (CoPCNTs) have been successfully controllable synthesized via hydrothermal method at different temperature. The CoPCNTs sensors exhibited the highest response to CO and NH{sub 3} gases with response time of 4 s and 4.3 s, low detection limit of 5 ppm and 1 ppm at room temperature, respectively. The enhanced gas sensing could be ascribed to the synergistic effect between the tiny size of Co{sub 3}O{sub 4} and good conductivity of carbon nanotubes functionalized by polyethyleneimine. - Highlights: • The CNTs functionalized by polyethyleneimine provided a new functional structural. • The novel 1D structure could capture and migrate electrons quickly. • The Co{sub 3}O{sub 4} nanoparticles liked a snake winding around CNTs. • The gas sensor could work at room temperatures, which suit to practical application. - Abstract: A novel 1D Co{sub 3}O{sub 4}/polyethyleneimine-carbon nanotubes composites (CoPCNTs) have been successfully synthesized via hydrothermal method at different temperature. The CNTs functionalized by polyethyleneimine (PCNTs) provided a new material with new structural and functional properties. The PCNTs was used as loading guider and electron transfer path. The Co{sub 3}O{sub 4} nanoparticles (NPs) loaded on the PCNTs surface liked a snake winding around CNTs, and the size was about 5–10 nm. The gas sensing characteristics of the CoPCNTs sensors to carbon monoxide (CO) and ammonia (NH{sub 3}) were evaluated with different gas concentration. The CoPCNTs sensors grown at 160 °C exhibited the highest response to CO and NH{sub 3} gases with response time of 4 s and 4.3 s at room temperature (RT), respectively. Hence, the approach developed in this work would be important for the low-cost and large-scale production of the CoPCNTs materials with highly promising applications in gas sensors.

  13. Validity of the Néel-Arrhenius model for highly anisotropic Co{sub x}Fe{sub 3−x}O{sub 4} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Torres, T. E.; Ibarra, M. R. [Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, 50018 Zaragoza (Spain); Departamento de Física de la Materia Condensada, Facultad de Ciencias, Universidad de Zaragoza, 50009 Zaragoza (Spain); Laboratorio de Microscopias Avanzadas (LMA), Universidad de Zaragoza, 50018 Zaragoza (Spain); Lima, E. [División Resonancias Magnéticas, Centro Atómico Bariloche/CONICET, S. C. Bariloche 8400 (Argentina); Mayoral, A.; Ibarra, A. [Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, 50018 Zaragoza (Spain); Laboratorio de Microscopias Avanzadas (LMA), Universidad de Zaragoza, 50018 Zaragoza (Spain); Marquina, C. [Departamento de Física de la Materia Condensada, Facultad de Ciencias, Universidad de Zaragoza, 50009 Zaragoza (Spain); Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC—Universidad de Zaragoza, 50009 Zaragoza (Spain); Goya, G. F., E-mail: goya@unizar.es [Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, 50018 Zaragoza (Spain); Departamento de Física de la Materia Condensada, Facultad de Ciencias, Universidad de Zaragoza, 50009 Zaragoza (Spain)

    2015-11-14

    We report a systematic study on the structural and magnetic properties of Co{sub x}Fe{sub 3−x}O{sub 4} magnetic nanoparticles with sizes between 5 and 25 nm, prepared by thermal decomposition of Fe(acac){sub 3} and Co(acac){sub 2}. The large magneto-crystalline anisotropy of the synthesized particles resulted in high blocking temperatures (42 K < T{sub B} < 345 K for 5 < d < 13 nm) and large coercive fields (H{sub C} ≈ 1600 kA/m for T = 5 K). The smallest particles (〈d〉=5 nm) revealed the existence of a magnetically hard, spin-disordered surface. The thermal dependence of static and dynamic magnetic properties of the whole series of samples could be explained within the Neel–Arrhenius relaxation framework by including the thermal dependence of the magnetocrystalline anisotropy constant K{sub 1}(T), without the need of ad-hoc corrections. This approach, using the empirical Brükhatov-Kirensky relation, provided K{sub 1}(0) values very similar to the bulk material from either static or dynamic magnetic measurements, as well as realistic values for the response times (τ{sub 0} ≈ 10{sup −10}s). Deviations from the bulk anisotropy values found for the smallest particles could be qualitatively explained based on Zener's relation between K{sub 1}(T) and M(T)

  14. Graphitic g-C{sub 3}N{sub 4}-WO{sub 3} Composite: Synthesis and Photocatalytic Properties

    Energy Technology Data Exchange (ETDEWEB)

    Doan, An Tran; Thi, Xuan Dieu Nguyen; Nguyen, Phi Hung; Thi, Viet Nga Nguyen; Vo, Vien [Quy Nhon Univ., Quy Nhon (Viet Nam); Kim, Sung Jin [Ewha Womans Univ., Seoul (Korea, Republic of)

    2014-06-15

    Graphitic g-C{sub 3}N{sub 4}-WO{sub 3} composite was synthesized simply by decomposing melamine in the presence of WO{sub 3} at 500 .deg. C. The obtained material was characterized by XRD, SEM, IR and XPS. The results showed that the as-prepared composite exhibits orthorhombic WO{sub 3} phase coated by g-C{sub 3}N{sub 4} and the g-C{sub 3}N{sub 4} decomposed completely with N-doped WO{sub 3} remaining at elevated calcination temperatures. The photocatalytic activity of the composite was evaluated by the photodegradation of methylene blue under visible light. An enhancement in photocatalytic activity for the graphitic g-C{sub 3}N{sub 4}-WO{sub 3} composite compared to the conventional nitrogen-doped WO{sub 3} was observed, which can be attributed to the presence of g-C{sub 3}N{sub 4} in the material.

  15. First synthesis of Cr{sub 3}C{sub 2} nanowhiskers by low-temperature vaccum carburization from precursor

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Yongzhong, E-mail: jyzcd@163.com [Department of Materials Science and Engineering, Sichuan University of Science and Engineering, Zigong City, 643000 (China); Zhang, Zhengquan [Department of Materials Science and Engineering, Sichuan University of Science and Engineering, Zigong City, 643000 (China); Ye, Faming [Department of Materials Science and Engineering, Sichuan University of Science and Engineering, Zigong City, 643000 (China); Deyang Haohua Qingping Linkuang Co. Ltd., Deyang City, 618000 (China); Liu, Dongliang; Chen, Jian; Yang, Ruisong [Department of Materials Science and Engineering, Sichuan University of Science and Engineering, Zigong City, 643000 (China)

    2016-08-15

    To assist a widespread application of chromium carbide (Cr{sub 3}C{sub 2}), it is important to synthesize Cr{sub 3}C{sub 2} nanowhiskers and but there are almost no related reports. In this letter, we first reported a low-lost synthesis of Cr{sub 3}C{sub 2} nanowhiskers at 800 °C by vacuum carburization process using precursor powders as raw materials without Fe/Co/Ni catalysts. X-ray diffraction (XRD) data confirm that Cr{sub 3}C{sub 2} nanowhiskers have a single-phase orthorhombic structure. A homogeneous chemical composition can be obtained in the calcining product from precursor, which reduces significantly the synthesis temperature. Morphological studies using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) show Cr{sub 3}C{sub 2} nanowhiskers have a clean and smooth surface with a diameter size of ∼50 nm. - Highlights: • Cr{sub 3}C{sub 2} nanowhiskers were first synthesized at 800 °C by a novel LVCP method. • A homogeneous chemical composition from precursor reduces synthesis temperature. • Cr{sub 3}C{sub 2} nanowhiskers have a single-phase structure and a diameter size of ∼50 nm.

  16. Preparation and characterization of polyaniline (PANI)-Mn{sub 3}O{sub 4} nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Durmus, Z. [Department of Chemistry, Fatih University, B. Cekmece, 34500 Istanbul (Turkey); Baykal, A., E-mail: hbaykal@fatih.edu.t [Department of Chemistry, Fatih University, B. Cekmece, 34500 Istanbul (Turkey); Kavas, H. [Department of Physics, Fatih University, B. Cekmece, 34500 Istanbul (Turkey); Soezeri, H. [TUBITAK-UME, National Metrology Institute, PO Box 54, 41470 Gebze-Kocaeli (Turkey)

    2011-03-01

    Polyaniline (PANI)-Mn{sub 3}O{sub 4} nanocomposite was synthesized by a combination of sonochemical synthesis of Mn{sub 3}O{sub 4} NP's and in-situ polymerization of aniline. Structural characteristics were evaluated by XRD, FT-IR, TGA, VSM, TEM and SEM analysis, and conduction characteristics were evaluated by total conductivity measurements in the temperature range of 20-100 {sup o}C and frequency range of 0.1 Hz-1 MHz. Our findings show that PANI is successfully coated on nanoparticles surface and overall conductivity of nanocomposite is approximately 50-1000 times higher than that of uncapped Mn{sub 3}O{sub 4} or PANI base with increase in temperature. Morphology of the synthesized powder was observed to be thin nanosheets with a thickness of 2-3 nm based on SEM analysis. Room temperature magnetization curves for nanocomposite show no hysteresis, indicating the super-paramagnetic character of the sample in the region of measured field strength. {sigma}{sub AC} increased after polyaniline coating. -- Research highlights: {yields} Polyaniline-Mn{sub 3}O{sub 4} (PANI-Mn{sub 3}O{sub 4}) nanocomposite was prepared sonochemically by in-situ chemical oxidative polymerization of polyaniline in the presence of cetyl trimethyl ammonium bromide. {yields} The average crystallite size of nanocomposite was found to be 25.5{+-}0.1 nm using the Scherrer's equation. Nanocomposite's overall conductivity is approximately 50-1000 times higher than that of uncapped Mn{sub 3}O{sub 4} or PANI with increase in temperature. {yields} The absence of hysteresis curve for the product indicates the super-paramagnetic character in the region of measured field strength.

  17. Fabrication and characterization of perovskite-based CH{sub 3}NH{sub 3}Pb{sub 1-x}Ge{sub x}I{sub 3}, CH{sub 3}NH{sub 3}Pb{sub 1-x}Tl{sub x}I{sub 3} and CH{sub 3}NH{sub 3}Pb{sub 1-x}In{sub x}I{sub 3} photovoltaic devices

    Energy Technology Data Exchange (ETDEWEB)

    Ohishi, Yuya; Oku, Takeo, E-mail: oku@mat.usp.ac.jp; Suzuki, Atsushi [Department of Materials Science, The University of Shiga Prefecture 2500 Hassaka, Hikone, Shiga 522-8533 (Japan)

    2016-02-01

    Perovskite-type CH{sub 3}NH{sub 3}PbI{sub 3}-based photovoltaic devices were fabricated and characterized. Doping effects of thallium (Tl), indium (In), or germanium (Ge) element on the photovoltaic properties and surface structures of the perovskite phase were investigated. The open circuit voltage increased by Ge addition, and fill factors were improved by adding a small amount of Ge, Tl or In. In addition, the wavelength range of incident photon conversion efficiencies was expanded by the Tl addition.

  18. Structure determination and optical properties of CsSm(PO{sub 3}){sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Ben Hassen, N.; Ferhi, M., E-mail: ferhi.mounir@gmail.com; Horchani-Naifer, K.; Férid, M.

    2015-03-15

    Graphical abstract: Projection of the CsSm(PO{sub 3}){sub 4} structure viewing along the a axis. - Highlights: • Single crystal of a new polyphosphate CsSm(PO{sub 3}){sub 4} has been synthesized. • The obtained compound has been characterized by several techniques. • The crystal structure of CsSm(PO{sub 3}){sub 4} has been resolved. • Spectroscopic properties of Sm{sup 3+} in CsSm(PO{sub 3}){sub 4} have been performed. - Abstract: A new alkali metal-rare earth polyphosphate CsSm(PO{sub 3}){sub 4} has been synthesized by flux method. The obtained compound has been characterized by means of single crystal X-ray diffraction, Fourier transform infrared (FTIR) and Raman scattering spectroscopies. It crystallizes in the monoclinic space group P2{sub 1}/n with the following unit-cell parameters: a = 10.382(2), b = 8.978(6), c = 11.205(4) Å, β = 106.398(3)° and Z = 4. The structure of CsSm(PO{sub 3}){sub 4} is an infinite three-dimensional framework made up of double spiral (PO{sub 3}){sub n} chains linked with neighboring SmO{sub 8} and CsO{sub 11} polyhedra. Spectroscopic properties of Sm{sup 3+} in this new compound including excitation, emission, and kinetic measurement have been performed. The emission spectrum shows four transitions characteristics of Sm{sup 3+} in the orange–red region by excitation wavelength at 400 nm. The decay time curve of {sup 4}G{sub 5/2} → {sup 6}H{sub 7/2} transition has been also registered and fitted to a single exponential function.

  19. Synthesis and characterization of superconductor Bi{sub 3}O{sub 2}S{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Gaobin [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); School of Science, University of Science and Technology Liaoning, Anshan 114051 (China); Li, Da; Li, Shaojie [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Wang, Jian [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); School of Science, University of Science and Technology Liaoning, Anshan 114051 (China); Liu, Wei; Zhang, Zhidong [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)

    2015-03-15

    Highlights: • Layered superconductor Bi{sub 3}O{sub 2}S{sub 3} have been successfully prepared with Bi{sub 2}O{sub 2}S precursor. • The zero resistivity transition temperature of bulk Bi{sub 3}O{sub 2}S{sub 3} is observed at 4.62 K. • The susceptibility at 2 K is 0.031 emu Oe{sup −1} g{sup −1}, indicating a perfect diamagnetism. - Abstract: Bulk and nanoscale powder layered superconductor Bi{sub 3}O{sub 2}S{sub 3} have been successfully prepared via conventional solid-state reaction route. The diffraction peaks observed for Bi{sub 3}O{sub 2}S{sub 3}, except for the small impurity peaks belong to Bi{sub 28}O{sub 32}(SO{sub 4}){sub 10}, can be indexed to the orthorhombic (I4/mmm tetragonal) phase for Bi{sub 3}O{sub 2}S{sub 3} with cell constants a = 3.961 Å, c = 41.316 Å. The pill comprised of nanoscale Bi{sub 3}O{sub 2}S{sub 3} behaves like insulator. However the zero resistivity of bulk Bi{sub 3}O{sub 2}S{sub 3} is observed at 4.62 K. The superconductivity is also proved by the Meissner effect from the zero-field cooled and field cooled dc magnetization measurements, and the diamagnetic susceptibility which reflects shielding volume fraction of superconductor at 2 K is about −0.031 emu Oe{sup −1} g{sup −1}, indicating a perfect diamagnetism.

  20. Niobium thiobromide, Nb{sub 3}SBr{sub 7}, with triangle Nb{sub 3} cluster: Structure and bonding

    Energy Technology Data Exchange (ETDEWEB)

    Khvorykh, G.V.; Shevelkov, A.V.; Dolgikh, V.A.; Popovkin, B.A. [Moscow State Univ., Moscow (Russian Federation)

    1995-12-01

    The reaction of Nb, S, and Br{sub 2} in a sealed quartz ampoule at 550{degrees}C yielded Nb{sub 3}SBr{sub 7}. The structure of Nb{sub 3}SBr{sub 7} determined by the single-crystal X-ray diffraction method (P3m1, a=7.1012(6){angstrom}, c=6.3040(9){angstrom}, V=275.30(9){angstrom}{sup 3}, Z=1, d{sub calc}=5.248(2) g.cm{sup 3}, R=0.0395, R{sub w}=0.0392) consists of one-layer packing of ([Nb{sub 3}SBr{sub 3}]Br{sub 6/2}Br{sub 3/3}){sup 2}{infinity} layers. The molecular orbitals of the model anions [Nb{sub 3}Br{sub 13}]{sup 5-} and [Nb{sub 3}SBr{sub 12}]{sup {minus}5-}, which involve the triangle Nb{sub 3} cluster with the nearest ligand environment in the structures of Nb{sub 3}Br{sub 8} and Nb{sup 3}SBr{sub 7} respectively, were calculated by applying the extended Huckel method. The HOMO in [Nb{sub 3}Br{sub 13}]{sup 5-} has slightly metal-metal bonding character which is consistent with an Nb-Nb bond length increase from 2.88 {angstrom} in a seven-electron Nb{sub 3}Br{sub 8} to 2.896(1) {angstrom} in a six-electron Nb{sub 3}SBr{sub 7}. The bonding schemes are in accordance with magnetic properties of Nb{sub 3}Br{sub 8}, which is a paramagnetic, and Nb{sub 3}SBr{sub 7}, which is diamagnetic.

  1. Response study of a CF{sub 3}I Superheated Droplet Detector for dark matter applications

    Energy Technology Data Exchange (ETDEWEB)

    Morlat, T. [Centro de Fisica Nuclear, Universidade de Lisboa, 1649-003 Lisbon (Portugal)], E-mail: tomoko@itn.mces.pt; Giuliani, F.; Girard, T.A. [Centro de Fisica Nuclear, Universidade de Lisboa, 1649-003 Lisbon (Portugal); Ramos, A.R.; Felizardo, M.; Marques, J.G. [Centro de Fisica Nuclear, Universidade de Lisboa, 1649-003 Lisbon (Portugal); Instituto Tecnologico e Nuclear, Estrada Nacional 10, 2686-953 Sacavem (Portugal)

    2007-09-21

    The application of Superheated Droplet Detectors (SDDs) to dark matter searches has been confined to the spin-dependent (SD) sector owing to the high content of fluorine of these refrigerants (C{sub 2}ClF{sub 5}, C{sub 4}F{sub 10}, C{sub 3}F{sub 8}, etc.). Given the competitive results of these devices, because of their thermodynamically tunable insensitivity to spurious background particles ({mu}{sup -}, e{sup -}), we examine the potential impact of a heavy SDD loaded with trifluoroiodomethane (CF{sub 3}I) in the spin-independent (SI) sector.

  2. Superconductor (Nb)-charge density wave (NbSe sub 3) point-contact spectroscopy

    CERN Document Server

    Sinchenko, A A

    2003-01-01

    Measurements of differential current-voltage (I-V) characteristics of point contacts between Nb and the charge density wave (CDW) conductor NbSe sub 3 formed along the conducting chain direction are reported. Below the superconducting transition of Nb, we have clearly observed Andreev reflection of the gapless electrons of NbSe sub 3. Analysis of the spectra obtained indicates that when the energy of injected particles exceeds the superconducting energy gap, the superconductivity near the S-CDW interface is suppressed because of non-equilibrium effects.

  3. g-C{sub 3}N{sub 4} decorated ZnO nanorod arrays for enhanced photoelectrocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Kuang, Pan-Yong; Su, Yu-Zhi; Chen, Gao-Feng [School of Chemistry and Chemical Engineering/Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, Guangzhou University, Guangzhou 510006 (China); Luo, Zhuo, E-mail: lz8215353@126.com [Hunan Key Laboratory of Applied Environmental Photocatalysis, Changsha University, Changsha 410022 (China); Xing, Shu-Yang [Hunan Key Laboratory of Applied Environmental Photocatalysis, Changsha University, Changsha 410022 (China); Li, Nan [School of Chemistry and Chemical Engineering/Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, Guangzhou University, Guangzhou 510006 (China); Liu, Zhao-Qing, E-mail: lzqgzu@gzhu.edu.cn [School of Chemistry and Chemical Engineering/Guangzhou Key Laboratory for Environmentally Functional Materials and Technology, Guangzhou University, Guangzhou 510006 (China)

    2015-12-15

    Graphical abstract: - Highlights: • Highly ordered g-C{sub 3}N{sub 4}/ZnO NRAs were prepared through thermal condensation of melamine. • Efficient electron–hole pair separation and transfer rates were achieved in the heterojunction. • The as-prepared g-C{sub 3}N{sub 4}/ZnO NRAs exhibit enhanced photoelectrocatalytic performance. - Abstract: Heterojunction can not only offer a wide range of solar light absorption but also facilitate the separation of photoinduced charge carriers, and thereby lead to enhanced photoelectrochemical efficiency. Herein, we report the heterostructured g-C{sub 3}N{sub 4}/ZnO nanorod arrays (NRAs) for enhanced photoelectrocatalytic performance. The g-C{sub 3}N{sub 4} shell layer of about 20–30 nm was coated on the surface of ZnO nanorod uniformly through thermal annealing the melamine precursor. Compared to the pristine ZnO and g-C{sub 3}N{sub 4}, the as-prepared g-C{sub 3}N{sub 4}/ZnO NRAs exhibit enhanced photoelectrocatalytic activity for methylene blue (MB) decolorization under visible light illumination. This enhancement of photoelectrocatalytic performance may be mainly attributed to improved separation efficiency of charge carriers from photoexcited g-C{sub 3}N{sub 4} to ZnO across the g-C{sub 3}N{sub 4}/ZnO interfaces.

  4. Sol-gel synthesis, solid sintering, and thermal stability of single-phase YCoO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Guanlin; Shen, Hongzhi; Li, Liang; Zhou, Jing; Yang, Hang [State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012 (China); Xue, Yanfeng [College of Physics, Jilin University, Changchun 130012 (China); Feng, Shuo [School of Jet Propulsion, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Xu, Dapeng [State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012 (China); College of Physics, Jilin University, Changchun 130012 (China)

    2012-07-15

    Using Y(NO{sub 3}){sub 3}.6H{sub 2}O and Co(NO{sub 3}){sub 2}.6H{sub 2}O as the starting materials, the single-phase YCoO{sub 3} has been synthesized by a two-step process involving a sol-gel technique and a sintering method. The structure, electromagnetic properties, and thermal stability of the synthesized samples were measured by XRD, thermogravimetry and differential thermal analysis (TG-DTA), TEM, and vibration sample magnetometer (VSM). The experimental results show that the synthesis conditions of the single-phase YCoO{sub 3} are 900-950 C for 10 h in air. And the synthesis temperature is extended to 900-1000 C and the sintering time is shortened to 5 h in an oxygen atmosphere. The synthesized powders have orthorhombic structure, with a diameter of {proportional_to}30 nm, which is stable in air below 1050 C and in oxygen atmosphere below 1100 C. Above those temperatures, YCoO{sub 3} decomposes into Y{sub 2}O{sub 3} and Co{sub 3}O{sub 4}. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Vibrational properties of epitaxial Bi{sub 4}Te{sub 3} films as studied by Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Hao; Pan, Wenwu; Chen, Qimiao; Wu, Xiaoyan [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050 (China); University of Chinese Academy of Sciences, No.19A Yuquan Road, Beijing 100049 (China); Song, Yuxin, E-mail: songyuxin@mail.sim.ac.cn, E-mail: shumin@chalmers.se; Gong, Qian [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050 (China); Lu, Pengfei [State Key Laboratory of Information Photonics and Optical Communications, Ministry of Education, Beijing University of Posts and Telecommunications, P.O. Box 72, Beijing 100876 (China); Wang, Shumin, E-mail: songyuxin@mail.sim.ac.cn, E-mail: shumin@chalmers.se [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050 (China); Department of Microtechnology and Nanoscience, Chalmers University of Technology, 41296 Gothenburg (Sweden)

    2015-08-15

    Bi{sub 4}Te{sub 3}, as one of the phases of the binary Bi–Te system, shares many similarities with Bi{sub 2}Te{sub 3}, which is known as a topological insulator and thermoelectric material. We report the micro-Raman spectroscopy study of 50 nm Bi{sub 4}Te{sub 3} films on Si substrates prepared by molecular beam epitaxy. Raman spectra of Bi{sub 4}Te{sub 3} films completely resolve the six predicted Raman-active phonon modes for the first time. Structural features and Raman tensors of Bi{sub 4}Te{sub 3} films are introduced. According to the wavenumbers and assignments of the six eigenpeaks in the Raman spectra of Bi{sub 4}Te{sub 3} films, it is found that the Raman-active phonon oscillations in Bi{sub 4}Te{sub 3} films exhibit the vibrational properties of those in both Bi and Bi{sub 2}Te{sub 3} films.

  6. CsPbBr{sub 3} nanocrystal saturable absorber for mode-locking ytterbium fiber laser

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yan; Li, Yue; Xu, Jianqiu; Tang, Yulong, E-mail: yulong@sjtu.edu.cn [Key Laboratory for Laser Plasmas (MOE), Department of Physics and Astronomy, Collaborative Innovation Center of IFSA, Shanghai Jiao Tong University, Shanghai 200240 (China); Hu, Zhiping; Tang, Xiaosheng [Key Laboratory of Optoelectronic Technology and Systems of the Education Ministry of China, College of Optoelectronic Engineering, Chongqing University, Chongqing 400044 (China)

    2016-06-27

    Cesium lead halide perovskite nanocrystals (CsPbX{sub 3}, X = Cl, Br, I) have been reported as efficient light-harvesting and light-emitting semiconductor materials, but their nonlinear optical properties have been seldom touched upon. In this paper, we prepare layered CsPbBr{sub 3} nanocrystal films and characterize their physical properties. Broadband linear absorption from ∼0.8 to over 2.2 μm and nonlinear optical absorption at the 1-μm wavelength region are measured. The CsPbBr{sub 3} saturable absorber (SA), manufactured by drop-casting of colloidal CsPbBr{sub 3} liquid solution on a gold mirror, shows modulation depth and saturation intensity of 13.1% and 10.7 MW/cm{sup 2}, respectively. With this SA, mode-locking operation of a polarization-maintained ytterbium fiber laser produces single pulses with duration of ∼216 ps, maximum average output power of 10.5 mW, and the laser spectrum is centered at ∼1076 nm. This work shows that CsPbBr{sub 3} films can be efficient SA candidates for fiber lasers and also have great potential to become broadband linear and nonlinear optical materials for photonics and optoelectronics.

  7. Oxidative and antibacterial activity of Mn{sub 3}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Chowdhury, Al-Nakib, E-mail: nakib@chem.buet.ac.bd [Department of Chemistry, Bangladesh University of Engineering and Technology, Dhaka-1000 (Bangladesh); Azam, Md. Shafiul, E-mail: azam@ualberta.ca [Department of Chemistry, Bangladesh University of Engineering and Technology, Dhaka-1000 (Bangladesh); Aktaruzzaman, Md.; Rahim, Abdur [Department of Chemistry, Bangladesh University of Engineering and Technology, Dhaka-1000 (Bangladesh)

    2009-12-30

    Mn{sub 3}O{sub 4} nanoparticles with diameter ca. 10 nm were synthesized by the forced hydrolysis of Mn(II) acetate at 80 deg. C. The X-ray diffraction (XRD), Fourier transform infra red (FT-IR) spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques were employed to study structural features and chemical composition of the nanoparticles. The unique oxidative activity of the Mn{sub 3}O{sub 4} nanoparticles was demonstrated in the polymerization and dye degradation reactions. On adding Mn{sub 3}O{sub 4} suspension to an acidic solution of aniline, yielded immediately green sediment of polyaniline (PANI). The organic dyes, viz., methylene blue (MB) and procion red (PR) were found to be completely decolorized from their aqueous solution on treating the dyes with Mn{sub 3}O{sub 4} suspension in acidic media. The Mn{sub 3}O{sub 4} nanoparticles also showed a clear antibacterial activity against the Vibrio cholerae, Shigella sp., Salmonella sp., and Escherichi coli bacteria that cause cholera, dysentery, typhoid, and diarrhea diseases, respectively.

  8. Emission analysis of Pr{sup 3+} and Tm{sup 3+}: Ca{sub 2}Gd{sub 2}W{sub 3}O{sub 14} phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Sailaja, S. [Department of Physics (Research Centre), S.V. Degree College, Kadapa 516003 (India); Dhoble, S.J. [Department of Physics, RTM Nagpur University, Nagpur 440 001 (India); Nageswara Raju, C. [Department of Physics (Research Centre), S.V. Degree College, Kadapa 516003 (India); Sudhakar Reddy, B., E-mail: drbsreddyphd@gmail.com [Department of Physics (Research Centre), S.V. Degree College, Kadapa 516003 (India)

    2012-01-01

    5 mol% of Pr{sup 3+} and Tm{sup 3+} ions activated calcium gadolinium tungstate (Ca{sub 2}Gd{sub 2}W{sub 3}O{sub 14}) phosphors were synthesized by traditional solid state reaction method. Crystalline phase structure was identified from the X-ray diffraction (XRD) profiles. From the scanning electron microscopy (SEM) images, we have observed the agglomeration of the particles, and average grain size is around 40-300 nm. Using the energy dispersive X-ray analysis (EDAX) and Fourier transform infrared (FTIR) spectra, identified the elements and functional groups present in the prepared phosphors. The emission spectrum of Pr{sup 3+}: Ca{sub 2}Gd{sub 2}W{sub 3}O{sub 14} powder phosphors have shown an intense red emission at 615 nm with the excitation wavelength {lambda}{sub exci}=450 nm and thus these red color emitting powder phosphors are used as one of the components in the preparation of WLEDs. The excitation spectrum of Tm{sup 3+}: Ca{sub 2}Gd{sub 2}W{sub 3}O{sub 14} powder phosphor has shown a ligand to metal charge transfer (W-O) band (LMCT) within the WO{sub 4}{sup 2-} group. Emission spectrum of Tm{sup 3+}: Ca{sub 2}Gd{sub 2}W{sub 3}O{sub 14} phosphors have shown blue emissions at 453 nm ({sup 1}D{sub 2}{yields}{sup 3}F{sub 4}).

  9. Preparation and characterizations of Ba(Zr,Ti)O{sub 3}/(Ba,Sr)TiO{sub 3} heterostructures grown on (LaAlO{sub 3}){sub 0.3}(Sr{sub 2}AlTaO{sub 6}){sub 0.35} single crystal substrates by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Chan, N.Y.; Gao, G.Y.; Wang, Y. [Department of Applied Physics and Materials Research Centre, Hong Kong Polytechnic University (Hong Kong); Chan, H.L.W., E-mail: apahlcha@inet.polyu.edu.h [Department of Applied Physics and Materials Research Centre, Hong Kong Polytechnic University (Hong Kong)

    2010-10-01

    Epitaxial perovskite (Ba{sub 0.7}Sr{sub 0.3})TiO{sub 3} (BST), Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3} (BZT), Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}/(Ba{sub 0.7}Sr{sub 0.3})TiO{sub 3}(BZT/BST) and Ba{sub 0.85}Sr{sub 0.15}Zr{sub 0.1}Ti{sub 0.9}O{sub 3} (BSZT) thin films were grown on (LaAlO{sub 3}){sub 0.3}(Sr{sub 2}AlTaO{sub 6}){sub 0.35} (LSAT)[001]single crystal substrate coated with conducting oxide LaNiO{sub 3}(LNO) by pulsed laser deposition. X-ray diffraction, atomic force microscopy and electrical measurements were used to characterize the thin films. The {theta}-2{theta} linear scan indicated that the thin films with LNO layer show (001) orientations perpendicular to the substrate. Smooth and dense surface with grain size of 30 nm-80 nm were observed. The relative permittivity of the BST, BZT/BST, BZT and BSZT thin films are 1101, 799, 584 and 1784 respectively at 10 kHz. The tunability of the thin films are 39%, 32%, 44% and 60%. The results show that BSZT film has the highest tunability.

  10. Structural and optical analysis on europium doped AZrO{sub 3} (A=Ba, Ca, Sr) phosphor for display devices application

    Energy Technology Data Exchange (ETDEWEB)

    Dubey, Vikas, E-mail: jsvikasdubey@gmail.com [Department of Physics, Bhilai Institute of Technology Raipur, 493661 (India); Tiwari, Neha [Department of Physics, Govt. Model Science College, Jabalpur (India)

    2016-05-06

    Behavior displayed by europium doped AZrO{sub 3} phosphor which was synthesized by solid state reaction method. For synthesis of BaZrO{sub 3}, SrZrO{sub 3} and CaZrO{sub 3} phosphor with fixed concentration of europium ion was calcination at 1000°C and sintered at 1300°C following intermediate grinding. Synthesized sample was characterized by X-ray diffraction analysis and crystallite sized was calculated by Scherer’s formula. From PL spectra of prepared phosphors shows intense emission centred at 612nm (red emission) with high intensity for SrZrO{sub 3}:Eu{sup 3+}. For europium doped BaZrO{sub 3} and CaZrO{sub 3} (613nm) phosphor shows less intense PL spectra as compared to SrZrO{sub 3}:Eu{sup 3+}. The strong emission peak of AZrO{sub 3}:Eu{sup 3+} phosphor is due to forced electric dipole transition of {sup 5}D{sub 0} to {sup 7}F{sub 2} centered at 612 and 613nm. It is characteristic red emission for europium ion. The excitation spectra of AZrO{sub 3}:Eu{sup 3+} phosphor mainly consists of the charge transfer and (CTB) of Eu{sup 3+} located in 200–350 nm centred at 254nm. The present phosphors can act as single host for red light emission in display devices. The CIE coordinates were calculated by Spectrophotometric method using the spectral energy distribution of the AZrO{sub 3}:Eu{sup 3+} sample.

  11. Synthesis and characterization of magnetic diphase ZnFe{sub 2}O{sub 4}/{gamma}-Fe{sub 2}O{sub 3} electrospun fibers

    Energy Technology Data Exchange (ETDEWEB)

    Arias, M. [Department of Physics-Mathematics, University of Puerto Rico at Cayey, 205 Avenue Antonio R. Barcelo, Cayey 00736 (Puerto Rico); Instituto Tecnologico de Santo Domingo (INTEC), Avenida de Los Proceres, Gala, P.O. Box 342-9 and 249-2, Santo Domingo (Dominican Republic); Pantojas, V.M., E-mail: victor.pantojas@upr.edu [Department of Physics-Mathematics, University of Puerto Rico at Cayey, 205 Avenue Antonio R. Barcelo, Cayey 00736 (Puerto Rico); Perales, O. [Department of Engineering Science and Materials, University of Puerto Rico at Mayagueez, Mayagueez 00680-9044 (Puerto Rico); Institute for Functional Nanomaterials, University of Puerto Rico, San Juan 00936 (Puerto Rico); Otano, W. [Department of Physics-Mathematics, University of Puerto Rico at Cayey, 205 Avenue Antonio R. Barcelo, Cayey 00736 (Puerto Rico); Institute for Functional Nanomaterials, University of Puerto Rico, San Juan 00936 (Puerto Rico)

    2011-08-15

    Magnetic nanofibers of ZnFe{sub 2}O{sub 4}/{gamma}-Fe{sub 2}O{sub 3} composite were synthesized by electrospinning from a sol-gel solution containing a molar ratio (Fe/Zn) of 3. The effects of the calcination temperature on phase composition, particle size and magnetic properties have been investigated. Zinc ferrite fibers were obtained by calcinating the electrospun fibers in air from 300 to 800 deg. C and characterized by thermogravimetric analyses, Fourier transformed infrared spectroscopy, X-ray photoemission spectroscopy, X-ray diffraction, vibration sample magnetometry and magnetic force microscopy. The resulting fibers, with diameters ranging from 90 to 150 nm, were ferrimagnetic with high saturation magnetization as compared to bulk. An increase in the calcination temperature resulted in an increase in particle size and saturation magnetization. The observed increase in saturation magnetization was most likely due to the formation and growth of ZnFe{sub 2}O{sub 4}/{gamma}-Fe{sub 2}O{sub 3} diphase crystals. The highest saturation magnetization (45 emu/g) was obtained for fibers calcined at 800 deg. C. - Research Highlights: > Nanofibers were produced by electrospinning from a sol-gel. > ZnFe{sub 2}O{sub 4}/{gamma}-Fe{sub 2}O{sub 3} formed after cacination in air from 300 to 800 deg. C. > Fibers were ferrimagnetic with high saturation magnetization. > Crystallite particle size and saturation magnetization increase with temperature. > Magnetic domains with sizes similar to topographical grains were observed.

  12. Electronic characterization of LaAlO{sub 3}-SrTiO{sub 3} interfaces by scanning tunneling spectroscopy; Elektronische Charakterisierung von LaAlO{sub 3}-SrTiO{sub 3}-Grenzflaechen mittels Rastertunnelspektroskopie

    Energy Technology Data Exchange (ETDEWEB)

    Breitschaft, Martin

    2010-10-22

    When LaAlO{sub 3} is epitaxially grown on TiO{sub 2}-terminated SrTiO{sub 3}, an electrically conducting interface is generated. In this respect, the physical properties of the interface differ substantially from those of both LaAlO{sub 3} and SrTiO{sub 3}, which are electrically insulating in bulk form. This dissertation looks into the question of the microscopic structure of the conducting two-dimensional interface electron system. Comparing the electronic density of states of LaAlO{sub 3}-SrTiO{sub 3} interfaces measured by scanning tunneling spectroscopy with results of density functional theory, the interface electron system is found to be substantially coined by the hosting transition metal lattices. The comparison yields a detailed picture of the microscopic structure of the interface electron system. (orig.)

  13. Synthesis and Piezoelectric Properties Nd{sub 2}O{sub 3}-doped BaTiO{sub 3}-Bi{sub 0.5}(Na, K){sub 0.5}TiO{sub 3} by a Novel Composite-hydroxide-mediated Approach

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, T; Yin, S; Sato, T [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, Sendai 980-8577 (Japan); Hashimoto, T; Sasaki, A; Tokano, Y, E-mail: takeshik@mail.tagen.tohoku.ac.jp [NEC Tokin Corporation, Koriyama, Taihaku-ku, Sendai 980-8510 (Japan)

    2011-10-29

    High purity Nd{sub 2}O{sub 3}-doped (1-x)BaTiO{sub 3}-xBi{sub 0.5}(Na, K){sub 0.5}TiO{sub 3} (x = 0.00-0.08) were synthesized by a composite-hydroxide-mediated approach at 200 deg. C using a hydrothermal reaction apparatus with a rolling system. The powders with an average size of 100 nm in diameter were produced and were sintered to almost full theoretical density at low temperature such as 1200 deg. C for 2 h. Although (1--x)BaTiO{sub 3}-xBi{sub 0.5}(Na, K){sub 0.5}TiO{sub 3} could not be poled, Nd{sub 2}O{sub 3} additive was useful to proceed the polarization of (1-x)BaTiO{sub 3}-xBi{sub 0.5}(Na, K){sub 0.5}TiO{sub 3} ceramics.

  14. Environmental remediation of Cr(VI) solutions by photocatalytic reduction using Ag–Er(OH){sub 3} nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Malkhasian, Aramice Y.S., E-mail: amalkhasian10@gmail.com [Chemistry Department, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Mohamed, Reda M. [Chemistry Department, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Advanced Materials Department, Central Metallurgical R& D Institute, CMRDI, P.O. Box 87 Helwan, Cairo (Egypt); Center of Excellence in Environmental Studies, King Abdulaziz University, P.O. Box 80216, Jeddah 21589 (Saudi Arabia)

    2015-05-25

    Highlights: • Ag/Er(OH){sub 3} nanoparticles were used for photocatalytic reduction of Cr(VI). • Photocatalytic reduction of Cr(VI) was dependent on wt% of Ag. • Catalyst re-use revealed the present photocatalyst remain effective and active after five cycles. - Abstract: A hydrothermal method was use to prepare Er(OH){sub 3} nanoparticles, and a photoassisted deposition method was used to deposit silver onto the surface of those nanoparticles. Er(OH){sub 3} and Ag/Er(OH){sub 3} nanocomposites were characterized by BET, XRD, XPS, PL, UV–Vis and TEM measurements. The photocatalytic performance of the nanoparticles with respect to the photocatalytic reduction of chromium(VI) under UV light irradiation was determined. The results reveal that the silver particles were well dispersed onto the surface of the Er(OH){sub 3} nanoparticles. Additionally, the surface area of the Ag/Er(OH){sub 3} nanocomposites was observed to be smaller than that of the Er(OH){sub 3} nanoparticles due to the blocking of some pores of the Er(OH){sub 3} nanoparticles by the deposition of silver particles. The Ag/Er(OH){sub 3} nanocomposites (0.15 wt%) exhibit the lowest band gap and highest photocatalytic activity for the reduction of Cr(VI). The photocatalytic performance of the 0.15 wt% Ag/Er(OH){sub 3} nanocomposites was stable after the reuse of the nanoparticles for the reduction of Cr(VI) after five uses.

  15. Improving thermal and electrochemical performances of LiCoO{sub 2} cathode at high cut-off charge potentials by MF{sub 3} (M=Ce, Al) coating

    Energy Technology Data Exchange (ETDEWEB)

    Aboulaich, Abdelmaula, E-mail: a.aboulaich@managemgroup.com; Ouzaouit, Khalid; Faqir, Hakim; Kaddami, Abderrahman; Benzakour, Intissar; Akalay, Ismail

    2016-01-15

    Highlights: • Fluoride metal is successfully coated on the surface of LiCoO{sub 2}. • Easy and scalable method is adopted for the synthesis of coated-LiCoO{sub 2}. • Appropriate amount of AlF{sub 3} or CeF{sub 3} is beneficial to reduce cation disorder. • The electrochemical performances of coated LiCoO{sub 2} is significantly enhanced at higher potential (cycling efficiency and reversible capacity). • The coated cathode exhibits excellent thermal stability highlighted by calorimetric technique. - Abstract: Surface coating of LiCoO{sub 2} remained one of the efficient methods to enhance its electrochemical and thermal performances, especially at high cut-off potential. In this work, MF{sub 3} (M = Ce, Al) coated LiCoO{sub 2} was synthesized via co-precipitation method followed by a solid state reaction at 400 °C. The morphology and structure of the modified cathode material were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the fluoride compound MF{sub 3} is successfully coated on the surface of LiCoO{sub 2} cathode particles with an average layer thickness about 12 nm and 40 nm for AlF{sub 3} and CeF{sub 3}, respectively. The electrochemical tests show that the AlF{sub 3}-coating layer significantly enhances the cycling performance of LiCoO{sub 2} cathode material, even at high cut-off potential. While the bare LiCoO{sub 2} cathode displays fast fading at 4.6 V vs. Li{sup +}/Li cutoff potential, the surface-modified electrode exhibits the great capacity of 160 mAh g{sup −1} with excellent capacity retention on several cycles. We concluded that the electrochemical and the thermal enhancement at high potential are ascribed to the presence of MF{sub 3} coating layer which prevent the side reaction during the charge discharge process, alleviate the attack by the acidic electrolyte and reduce the damage of electrode structure.

  16. Effect of the thin Ga{sub 2}O{sub 3} layer in n{sup +}-ZnO/n-Ga{sub 2}O{sub 3}/p-Cu{sub 2}O heterojunction solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Minami, Tadatsugu; Nishi, Yuki; Miyata, Toshihiro, E-mail: tmiyata@neptune.kanazawa-it.ac.jp

    2013-12-31

    The influence of inserting a Ga{sub 2}O{sub 3} thin film as an n-type semiconductor layer on the obtainable photovoltaic properties in Cu{sub 2}O-based heterojunction solar cells was investigated with a transparent conductive Al-doped ZnO (AZO) thin film/n-Ga{sub 2}O{sub 3} thin film/p-Cu{sub 2}O sheet structure. It was found that this Ga{sub 2}O{sub 3} thin film can greatly improve the performance of Cu{sub 2}O-based heterojunction solar cells fabricated using polycrystalline Cu{sub 2}O sheets that had been prepared by a thermal oxidization of copper sheets. The obtained photovoltaic properties in the AZO/Ga{sub 2}O{sub 3}/Cu{sub 2}O heterojunction solar cells were strongly dependent on the deposition conditions of the Ga{sub 2}O{sub 3} films. The external quantum efficiency obtained in AZO/Ga{sub 2}O{sub 3}/Cu{sub 2}O heterojunction solar cells was found to be greater at wavelengths below approximately 500 nm than that obtained in AZO/Cu{sub 2}O heterojunction solar cells (i.e., prepared without a Ga{sub 2}O{sub 3} layer) at equivalent wavelengths. This improvement of photovoltaic properties is mainly attributed to a decrease in the level of defects at the interface between the Ga{sub 2}O{sub 3} thin film and the Cu{sub 2}O sheet. Conversion efficiencies over 5% were obtained in AZO/Ga{sub 2}O{sub 3}/Cu{sub 2}O heterojunction solar cells fabricated using an n-Ga{sub 2}O{sub 3} thin-film layer prepared with a thickness of 40–80 nm at an O{sub 2} gas pressure of approximately 1.7 Pa by a pulsed laser deposition. - Highlights: • We demonstrate high-efficiency Cu{sub 2}O-based p-n heterojunction solar cells. • A non-doped Ga{sub 2}O{sub 3} thin film was used as an n-type semiconductor layer. • The Ga{sub 2}O{sub 3} thin film was prepared at a low temperature by a low damage deposition. • p-type Cu{sub 2}O sheets prepared by thermal oxidization of copper sheets were used. • Conversion efficiencies over 5% were obtained in AZO/n-Ga{sub 2}O{sub 3}/p-Cu{sub 2

  17. Colloidal processing and rapid prototyping of Si{sub 3}N{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Liwu Wang

    1998-12-01

    Some progresses have been made in the wet shaping of Si{sub 3}N{sub 4} based on a better understanding of the colloidal behavior of suspensions and by improved pressure casting with porous polystyrene (PS) molds. This work illustrated that the combination of proper colloidal processing and rapid prototyping is an effective way to fabricate high-performance ceramics with complex shapes. In colloidal processing the packing density and microstructure of green bodies can be controlled if the interaction between ceramic particles in suspensions and the conditions under which the suspensions are consolidated are understood. Therefore, detailed studies on the surface chemistry of the Si{sub 3}N{sub 4} powder, the dispersing behavior of Si{sub 3}N{sub 4} suspensions, the influence of dispersants and the mechanism during powder consolidation into complex-shaped green bodies are performed. (orig.)

  18. Synchrotron X-ray scattering study of the substrate effects on relaxor Pb(Mg sub 1 sub / sub 3 Nb sub 2 sub / sub 3 sub -delta)O sub 3 /SrTiO sub 3 thin films

    CERN Document Server

    Seo, S H; Noh, D Y; Yamada, Y; Wasa, K

    2002-01-01

    Perovskite Pb(Mg sub 1 sub / sub 3 Nb sub 2 sub / sub 3 sub - subdelta)O sub 3 (PMN) thin films are grown epitaxially on on-axis SrTiO sub 3 (001) (STO), vicinal SrTiO sub 3 (001), and MgO (001) substrates by radio-frequency magnetron sputtering. The substrate effects on the structure of PMN thin films have been studied using synchrotron X-ray scattering technique. Initially PMN films grow in two-dimensional planar layers on the STO substrates, while they grow in the form of three-dimensional (3D) islands on the MgO substrate. The surface steps on the vicinal STO encourage the 3D island growth as the film thickness increases. We also found an unexpected monoclinic phase in PMN/STO and PMN/vicinal-STO films, which has been reported in bulk Pb(Mg sub 1 sub / sub 3 Nb sub 2 sub / sub 3)O sub 3 -35%PbTiO sub 3 solid solution. With increasing the film thickness, the unit cell structure of PMN films transforms from tetragonal to other structures as the strain relaxes. (author)

  19. Formation, stability and structural characterization of ternary MgUO{sub 2}(CO{sub 3}){sub 3}{sup 2-} and Mg{sub 2}UO{sub 2}(CO{sub 3}){sub 3}(aq) complexes

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jun-Yeop; Yun, Jong-Il [KAIST, Daejeon (Korea, Republic of). Dept. of Nuclear and Quantum Engineering; Vespa, Marika; Gaona, Xavier; Dardenne, Kathy; Rothe, Joerg; Rabung, Thomas; Altmaier, Marcus [Karlsruhe Institute of Technology, Karlsruhe (Germany). Inst. for Nuclear Waste Disposal

    2017-06-01

    The formation of ternary Mg-UO{sub 2}-CO{sub 3} complexes under weakly alkaline pH conditions was investigated by time-resolved laser fluorescence spectroscopy (TRLFS) and extended X-ray absorption fine structure (EXAFS) and compared to Ca-UO{sub 2}-CO{sub 3} complexes. The presence of two different Mg-UO{sub 2}-C{sub 3} complexes was identified by means of two distinct fluorescence lifetimes of 17±2 ns and 51±2 ns derived from the multi-exponential decay of the fluorescence signal. Slope analysis in terms of fluorescence intensity coupled with fluorescence intensity factor as a function of log [Mg(II)] was conducted for the identification of the Mg-UO{sub 2}-CO{sub 3} complexes forming. For the first time, the formation of both MgUO{sub 2}(CO{sub 3}){sub 3}{sup 2-} and Mg{sub 2}UO{sub 2}(CO{sub 3}){sub 3}(aq) species was confirmed and the corresponding equilibrium constants were determined as log β {sub 113}=25.8±0.3 and β {sub 213}=27.1±0.6, respectively. Complementarily, fundamental structural information for both Ca-UO{sub 2}-CO{sub 3} and Mg-UO{sub 2}-CO{sub 3} complexes was gained by extended EXAFS revealing very similar structures between these two species, except for the clearly shorter U-Mg distance (3.83 Aa) compared with U-Ca distance (4.15 Aa). These results confirmed the inner-sphere character of the Ca/Mg-UO{sub 2}-CO{sub 3} complexes. The formation constants determined for MgUO{sub 2}(CO{sub 3}){sub 3}{sup 2-} and Mg{sub 2}UO{sub 2}(CO{sub 3}){sub 3}(aq) species indicate that ternary Mg-UO{sub 2}-CO{sub 3} complexes contribute to the relevant uranium species in carbonate saturated solutions under neutral to weakly alkaline pH conditions in the presence of Mg(II) ions, which will induce notable influences on the U(VI) chemical species under seawater conditions.

  20. Design of polyoxometallate-titania composite film (H{sub 3}PW{sub 12}O{sub 40}/TiO{sub 2}) for the degradation of an aqueous dye Rhodamine B under the simulated sunlight irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Nan; Zhao, Yahui [School of Urban and Environmental Sciences, Northeast Normal University, Changchun 130024 (China); Liu, Hongbo [Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); Guo, Yihang [School of Urban and Environmental Sciences, Northeast Normal University, Changchun 130024 (China); Yuan, Xing, E-mail: yuanx@nenu.edu.cn [School of Urban and Environmental Sciences, Northeast Normal University, Changchun 130024 (China); Xu, Hui; Peng, Huifang; Qin, Hongwei [School of Urban and Environmental Sciences, Northeast Normal University, Changchun 130024 (China)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer A series of H{sub 3}PW{sub 12}O{sub 40}/TiO{sub 2} composite films were prepared by a single sol-gel-hydrothermal route. Black-Right-Pointing-Pointer The composite films exhibited higher simulated sunlight photocatalytic activity towards Rhodamine B. Black-Right-Pointing-Pointer The factors that influenced the RhB photocatalytic degradation were investigated. Black-Right-Pointing-Pointer The H{sub 3}PW{sub 12}O{sub 40}/TiO{sub 2} composite film can maintain the same activity level after three photocatalytic cycles without applying any separation step. - Abstract: A series of polyoxometallate/titania (H{sub 3}PW{sub 12}O{sub 40}/TiO{sub 2}) composite films with different H{sub 3}PW{sub 12}O{sub 40} loadings (6.3%, 7.7%, 14.7% and 16.7%) were prepared by a modified sol-gel-hydrothermal route followed by a spin-coating method. The smooth films are constructed by the well-distributed H{sub 3}PW{sub 12}O{sub 40}/TiO{sub 2} sphere with particle size in the range from 80 to 100 nm, and the bandgap of the composite films is somewhat narrower compared with as-prepared pure TiO{sub 2} film. As a novel photocatalytic material, the photocatalytic performances of the H{sub 3}PW{sub 12}O{sub 40}/TiO{sub 2} composite films were evaluated by the degradation and mineralization of an aqueous dye Rhodamine B (RB) under solar simulating Xe lamp irradiation (320 nm < {lambda} < 780 nm), and the enhanced photocatalytic activity in comparison to pure TiO{sub 2} film as well as the H{sub 3}PW{sub 12}O{sub 40}/TiO{sub 2} and Degussa P25 TiO{sub 2} powder was obtained. Additionally, the composite films can be reused at least for three times without losing their catalytic activity.

  1. Hydrothermal synthesis of urchin-like Co{sub 3}O{sub 4} nanostructures and their electrochemical sensing performance of H{sub 2}O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Barkaoui, Sami [Laboratoire des Matériaux Utiles, INRAP, Technopôle Sidi-Thabet, Tunis 2020 (Tunisia); Haddaoui, Marwa [Université de Tunis El-Manar, Faculté of Sciences, Laboratoire de Chimie Analytique et Electrochimie, Campus Universitaire de Tunis El-Manar, 2092 Tunis (Tunisia); Dhaouadi, Hassouna, E-mail: dhaouadihassouna@yahoo.fr [Laboratoire Matériaux Traitement et Analyse INRAP, Technopôle Sidi-Thabet, Tunis 2020 (Tunisia); Raouafi, Noureddine [Université de Tunis El-Manar, Faculté of Sciences, Laboratoire de Chimie Analytique et Electrochimie, Campus Universitaire de Tunis El-Manar, 2092 Tunis (Tunisia); Touati, Fathi [Laboratoire Matériaux Traitement et Analyse INRAP, Technopôle Sidi-Thabet, Tunis 2020 (Tunisia)

    2015-08-15

    Nanostructured tricobalt tetraoxide, Co{sub 3}O{sub 4}, was hydrothermally synthesized starting from cobalt dichloride hexahydrate (CoCl{sub 2}·6H{sub 2}O) and urea (H{sub 2}NCONH{sub 2}) as precursor and polyethylene glycol-400 (PEG-400) as a structure-directing agent. Uniform urchin-like nanostructures were hydrothermally obtained at 150 °C for 16 h, and the Co{sub 3}O{sub 4} morphology did not collapse after a subsequent calcination at 300 °C for 2 h. XRD measurements indicated that the average sizes of Co{sub 3}O{sub 4} particles prior and after heating at 300 °C are 64 and 44 nm, respectively. This material has been successfully used for the nanostructuration of screen-printed carbon electrodes (SPCEs) which were used for the sensitive electrochemical detection of hydrogen peroxide (H{sub 2}O{sub 2}). The sensor is endowed with a large dynamic range (0.1 to 50 µM) and a limit of detection of 0.145 µM. The as obtained results show that the Co{sub 3}O{sub 4} nanomaterial could be a candidate to be used as sensors for the detection of analytes. - Graphical abstract: The nanowires appear to have a common center and grow to the outside along the radial direction. - Highlights: • Nanostructured was hydrothermally prepared using PEG-400. • Uniform urchin-like Co{sub 3}O{sub 4} nanostructures were hydrothermally obtained. • X-ray diffraction showed a cubic structure after calcinations process. • Nanostructured Co{sub 3}O{sub 4} was used for the sensitive electrochemical detection of H{sub 2}O{sub 2.} • The sensor is endowed with a large dynamic range 0.1 to 50 µM.

  2. Facile synthesis of α-Fe{sub 2}O{sub 3} nanoparticles for high-performance CO gas sensor

    Energy Technology Data Exchange (ETDEWEB)

    Cuong, Nguyen Duc, E-mail: nguyenduccuong@hueuni.edu.vn [College of Sciences, Hue University, 77 Nguyen Hue, Phu Nhuan Ward, Hue City (Viet Nam); Faculty of Hospitality and Tourism, Hue University, 22 Lam Hoang, Vy Da Ward, Hue City (Viet Nam); Khieu, Dinh Quang; Hoa, Tran Thai [College of Sciences, Hue University, 77 Nguyen Hue, Phu Nhuan Ward, Hue City (Viet Nam); Quang, Duong Tuan [College of Education, Hue University, 34 Le Loi, Hue City (Viet Nam); Viet, Pham Hung [Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, 334 Nguyen Trai, Hanoi (Viet Nam); Lam, Tran Dai [Graduate University of Science and Technology, Vietnamese Academy of Science and Technology, Hanoi (Viet Nam); Hoa, Nguyen Duc [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST), No. 1, Dai Co Viet, Hanoi (Viet Nam); Hieu, Nguyen Van, E-mail: hieu@itims.edu.vn [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST), No. 1, Dai Co Viet, Hanoi (Viet Nam)

    2015-08-15

    Highlights: • We have demonstrated a facile method to prepare Fe{sub 2}O{sub 3} nanoparticles. • The gas sensing properties of α-Fe{sub 2}O{sub 3} have been invested. • The results show potential application of α-Fe{sub 2}O{sub 3} NPs for CO sensors in environmental monitoring. - Abstract: Iron oxide nanoparticles (NPs) were prepared via a simple hydrothermal method for high performance CO gas sensor. The synthesized α-Fe{sub 2}O{sub 3} NPs were characterized by X-ray diffraction, nitrogen adsorption/desorption isotherm, scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED). The SEM, TEM results revealed that obtained α-Fe{sub 2}O{sub 3} particles had a peanut-like geometry with hemispherical ends. The response of the α-Fe{sub 2}O{sub 3} NPs based sensor to carbon monoxide (CO) and various concentrations of other gases were measured at different temperatures. It found that the sensor based on the peanut-like α-Fe{sub 2}O{sub 3} NPs exhibited high response, fast response–recovery, and good selectivity to CO at 300 °C. The experimental results clearly demonstrated the potential application of α-Fe{sub 2}O{sub 3} NPs as a good sensing material in the fabrication of CO sensor.

  3. Rapid fabrication of Al{sub 2}O{sub 3} encapsulations for organic electronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Kamran; Ali, Junaid [Department of Mechatronics Engineering, Jeju National University, Jeju 690-756 (Korea, Republic of); Mehdi, Syed Murtuza [Department of Mechanical Engineering, NED University of Engineering and Technology, Karachi 75270 (Pakistan); Choi, Kyung-Hyun, E-mail: amm@jejunu.ac.kr [Department of Mechatronics Engineering, Jeju National University, Jeju 690-756 (Korea, Republic of); An, Young Jin [Jeonnam Science and Technology Promotion Center, Yeongam-gun, Jeollanam-do 526-897 (Korea, Republic of)

    2015-10-30

    Highlights: • Al{sub 2}O{sub 3} encapsulations are being developed through a unique R2R-AALD system. • The encapsulations have resulted in life time enhancement of PVP memristor devices. • The Al{sub 2}O{sub 3} encapsulated memristor performed with superior stability for four weeks. • Encapsulated devices performed efficiently even after bending test for 100 cycles. - Abstract: Organic electronics have earned great reputation in electronic industry yet they suffer technical challenges such as short lifetimes and low reliability because of their susceptibility to water vapor and oxygen which causes their fast degradation. This paper report on the rapid fabrication of Al{sub 2}O{sub 3} encapsulations through a unique roll-to-roll atmospheric atomic layer deposition technology (R2R-AALD) for the life time enhancement of organic poly (4-vinylphenol) (PVP) memristor devices. The devices were then categorized into two sets. One was processed with R2R-AALD Al{sub 2}O{sub 3} encapsulations at 50 °C and the other one was kept as un-encapsulated. The field-emission scanning electron microscopy (FESEM) results revealed that pin holes and other irregularities in PVP films with average arithmetic roughness (R{sub a}) of 9.66 nm have been effectively covered by Al{sub 2}O{sub 3} encapsulation having R{sub a} of 0.92 nm. The X-ray photoelectron spectroscopy XPS spectrum for PVP film showed peaks of C 1s and O 1s at the binding energies of 285 eV and 531 eV, respectively. The respective appearance of Al 2p, Al 2s, and O 1s peaks at the binding energies of 74 eV, 119 eV, and 531 eV, confirms the fabrication of Al{sub 2}O{sub 3} films. Electrical current–voltage (I–V) measurements confirmed that the Al{sub 2}O{sub 3} encapsulation has a huge influence on the performance, robustness and life time of memristor devices. The Al{sub 2}O{sub 3} encapsulated memristor performed with superior stability for four weeks whereas the un-encapsulated devices could only last for one

  4. Synthesis and photoluminescence properties of GdBO{sub 3}:Ln{sup 3+} (Ln = Eu, Tb) nanofibers by electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Hongzhi [Key Laboratory of Physics and Technology for Advanced Batteries, Ministry of Education, Jinlin University, Changchun 130000 (China); College of Physics, Jinlin University, Changchun 130000 (China); Feng, Shuo [School of Jet Propulsion, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Wang, Ying [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jinlin University, Changchun 130000 (China); Gu, Yipeng; Zhou, Jing; Yang, Hang [State Key Laboratory of Superhard Materials, Jinlin University, Changchun 130000 (China); Feng, Guanlin [Key Laboratory of Physics and Technology for Advanced Batteries, Ministry of Education, Jinlin University, Changchun 130000 (China); College of Physics, Jinlin University, Changchun 130000 (China); Li, Liang [State Key Laboratory of Superhard Materials, Jinlin University, Changchun 130000 (China); Wang, Wenquan [College of Physics, Jinlin University, Changchun 130000 (China); Liu, Xiaoyang [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jinlin University, Changchun 130000 (China); Xu, Dapeng, E-mail: xudp@jlu.edu.cn [Key Laboratory of Physics and Technology for Advanced Batteries, Ministry of Education, Jinlin University, Changchun 130000 (China); College of Physics, Jinlin University, Changchun 130000 (China)

    2013-02-15

    Highlights: Black-Right-Pointing-Pointer GdBO{sub 3}:Ln{sup 3+} nanofibers were synthesized successfully by electrospinning. Black-Right-Pointing-Pointer The samples have the average diameter of 150 nm and the flexible morphology. Black-Right-Pointing-Pointer The GdBO{sub 3}: Eu{sup 3+} nanofibers have the stronger orange emission. Black-Right-Pointing-Pointer The luminescence properties are different from the reported bulk material. Black-Right-Pointing-Pointer We describe the energy transform process of GdBO{sub 3}:Ln{sup 3+} system. - Abstract: GdBO{sub 3}:Ln{sup 3+} (Ln = Eu, Tb) nanofibers were synthesized using electrospinning combined with heat treatment. The synthesized nanofibers were characterized by X-ray diffraction, Raman spectroscopy, field emission-scanning electron microscopy, thermogravimetric and differential thermal analyses, and photoluminescence. The experimental results show that the flexible synthesized nanofibers have an average diameter of approximately 150 nm. The nanofibers consist of crystalline grains with diameters of about 40 nm and have a vaterite-type structure of GdBO{sub 3}. The GdBO{sub 3}:Eu{sup 3+} nanofibers exhibit strong orange and weak red emissions with a low ratio of red to orange emission intensities, which is different from those of the reported bulk materials and nanoparticles. The luminescence properties of the synthesized GdBO{sub 3}:Tb{sup 3+} nanofibers are essentially consistent with those of the synthesized GdBO{sub 3}:Tb{sup 3+}powders by solid-state reaction.

  5. Electric field effects in graphene/LaAlO{sub 3}/SrTiO{sub 3} heterostructures and nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Mengchen; Jnawali, Giriraj; Hsu, Jen-Feng; Dhingra, Shonali; Bi, Feng; Chen, Lu; D’Urso, Brian; Irvin, Patrick; Levy, Jeremy, E-mail: jlevy@pitt.edu [Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Lee, Hyungwoo; Ryu, Sangwoo; Eom, Chang-Beom [Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Ghahari, Fereshte; Ravichandran, Jayakanth; Kim, Philip [Department of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States)

    2015-06-01

    We report the development and characterization of graphene/LaAlO{sub 3}/SrTiO{sub 3} heterostructures. Complex-oxide heterostructures are created by pulsed laser deposition and are integrated with graphene using both mechanical exfoliation and transfer from chemical-vapor deposition on ultraflat copper substrates. Nanoscale control of the metal-insulator transition at the LaAlO{sub 3}/SrTiO{sub 3} interface, achieved using conductive atomic force microscope lithography, is demonstrated to be possible through the graphene layer. LaAlO{sub 3}/SrTiO{sub 3}-based electric field effects using a graphene top gate are also demonstrated. The ability to create functional field-effect devices provides the potential of graphene-complex-oxide heterostructures for scientific and technological advancement.

  6. Quasiparticle excitations in newly discovered antiperovskite superconductor ZnNNi{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Ohishi, Kazuki, E-mail: kazuki.ohishi@riken.j [Advanced Meson Science Laboratory, Nishina Center for Accelerator-Based Science, RIKEN, Wako 351-0198 (Japan); Ito, Takashi U.; Higemoto, Wataru [Advanced Science Research Center, Japan Atomic Energy Agency, Ibaraki 319-1195 (Japan); Yamazaki, Takahiro; Uehara, Akira; Kozawa, Katsuya; Kimishima, Yoshihide; Uehara, Masatomo [Department of Physics, Faculty of Engineering, Yokohama National University, Yokohama 240-8501 (Japan)

    2010-12-15

    We report on transverse field muon spin rotation measurements of the superconducting penetration depth {lambda} in newly discovered antiperovskite superconductor ZnNNi{sub 3} in order to investigate the symmetry of order parameter. The penetration depth at T = 0 K is estimated to be {lambda}(0) 362(2) nm. Temperature dependence of muon spin relaxation rate {sigma}{sub v} shows {approx}T{sup 2} dependence, suggesting unconventional superconductor.

  7. Optically stimulated luminescence of YAlO{sub 3}:Mn{sup 2+} for radiation dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Zhydachevskii, Ya. [Lviv Polytechnic National University, 12 Bandera, 79646 Lviv (Ukraine)], E-mail: crystal@polynet.lviv.ua; Suchocki, A.; Berkowski, M. [Institute of Physics, Polish Academy of Sciences, 32/46 Al. Lotnikow, 02668 Warsaw (Poland); Zakharko, Ya. [I.Franko Lviv National University, 107 Tarnavskogo St., 79017 Lviv (Ukraine)

    2007-04-15

    The optically stimulated luminescence (OSL) properties have been studied for YAlO{sub 3}:Mn{sup 2+} crystal applicable for thermoluminescent (TL) dosimetry of ionizing radiation and UV light. A high efficiency of optical stimulation by the blue-green light (450-500 nm) was demonstrated that allows to use the OSL procedure for non-heating readout of the irradiated samples. Mechanisms of the observed optical processes are discussed.

  8. Si{sub 3}N{sub 4} optomechanical crystals in the resolved-sideband regime

    Energy Technology Data Exchange (ETDEWEB)

    Davanço, M., E-mail: mdavanco@nist.gov [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Department of Applied Physics, California Institute of Technology, Pasadena, California 91125 (United States); Ates, S.; Liu, Y. [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Maryland NanoCenter, University of Maryland, College Park, Maryland 20742 (United States); Srinivasan, K. [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)

    2014-01-27

    We demonstrate sideband-resolved Si{sub 3}N{sub 4} optomechanical crystals supporting 10{sup 5} quality factor optical modes at 980 nm, coupled to ≈4 GHz frequency mechanical modes with quality factors of ≈3000. Optomechanical electromagnetically induced transparency and absorption are observed at room temperature and in atmosphere with intracavity photon numbers in excess of 10{sup 4}.

  9. Optimizing magnetic anisotropy of La{sub 1−x}Sr{sub x}MnO{sub 3} nanoparticles for hyperthermia applications

    Energy Technology Data Exchange (ETDEWEB)

    Rashid, Amin ur [Magnetism Laboratory, Department of Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan); Department of Applied Physical and Material Sciences, University of Swat, Khyber Pakhtunkhwa (Pakistan); Manzoor, Sadia, E-mail: sadia_manzoor@comsats.edu.pk [Magnetism Laboratory, Department of Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan)

    2016-12-15

    Maximizing the magnetothermal response of magnetic nanoparticles (MNP's) for hyperthermia applications is a complex problem, because it depends sensitively upon interrelated magnetic and structural parameters. The task is somewhat simpler for systems with fixed composition, e.g. Fe{sub 3}O{sub 4} or CoFe{sub 2}O{sub 4}, in which the particle size is the only means of modifying the magnetic anisotropy, and hence the magnetothermal response. In the La{sub 1−x}Sr{sub x}MnO{sub 3} system however, the magnetic interactions as well as the particle size both change with the Sr concentration x, which makes it a much more complex system for which to optimize the hyperthermia response. We have investigated the effect of magnetic anisotropy on the magnetothermal response of La{sub 1−x}Sr{sub x}MnO{sub 3} nanoparticles as a function of the particle size as well as the Sr concentration x where 0.20≤x≤0.45. The optimum particle size range is 25–30 nm for all concentrations, where the specific absorption rate (SAR) has a maximum. The linear response theory (LRT) has been applied to this system and good agreement has been found between the experimental and theoretically determined values of the SAR for samples lying in the single domain regime and having large enough anisotropy energies. The agreement is much better for the intermediate concentrations of 0.27 and 0.33, because of their large anisotropy as compared to other concentrations. It is concluded that the LRT can be successfully used to predict the SAR of these nanoparticles, provided they possess large enough effective anisotropies. Values of the ILP have been obtained for these samples and found to be comparable to those of magnetite and some commercial ferrofluids. - Highlights: • For La{sub 1-x}Sr{sub x}MnO{sub 3} system, the magnetic anisotropy is determined not only by the particle size, but also by the strontium content x, we made a systematic study of both these parameters on its magnetothermal

  10. Processing and structure/property relations in Ba(Zn sub 1 sub / sub 3 Ta sub 2 sub / sub 3)O sub 3 microwave ceramics

    CERN Document Server

    Qazi, I

    2001-01-01

    Microwave filters utilize extensively, complex perovskite barium zinc tantalate ceramics, due to their superior selectivity and near zero temperature coefficient. A study of Ba sub 1 sub - sub x Sr sub x [Zn sub 1 sub / sub 3 (Ta sub 1 sub - sub y Nb sub y) sub 2 sub / sub 3]O sub 3 (BSZNT) synthesised by a mixed oxide route was conducted to understand the relationship between structure/microstructure and dielectric properties. Densities >95% and 97Vo were achieved in undoped (x=0 y=0) and Sr sup + sup 2 and or Nb sup + sup 5 doped Ba(Zn sub 1 sub / sub 3 Ta sub 2 sub / sub 3)O sub 3 (BZT) respectively. The investigation found a reversible order-disorder phase transition in pure barium zinc tantalate at approx 1600 degC. X-ray diffraction (XRD) showed a disordered cubic phase above, and an ordered trigonal-phase below, 1600 degC. Thermogravimetric analysis detected weight loss due to zinc oxide evaporation beginning at approximately 1200 degC. Thus, non-perovskite phases such BaTa sub 2 O sub 6 , observed as ...

  11. Role of bromine doping on the photovoltaic properties and microstructures of CH{sub 3}NH{sub 3}PbI{sub 3} perovskite solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Atsushi; Okada, Hiroshi; Oku, Takeo [Department of Materials Science, The University of Shiga Prefecture 2500 Hassaka, Hikone, Shiga, 522-8533 (Japan)

    2016-02-01

    Organic-inorganic hybrid heterojunction solar cells containing CH{sub 3}NH{sub 3}PbI{sub 3} perovskite compound were fabricated using mesoporous TiO{sub 2} as the electronic transporting layer and spirobifluorence as the hole-transporting layer. The purpose of the present study is to investigate role of bromine (Br) doping on the photovoltaic properties and microstructure of CH{sub 3}NH{sub 3}PbI{sub 3} perovskite solar cells. Photovoltaic, optical properties and microstructures of perovskite-based solar cells were investigated. The X-ray diffraction identified crystal structure of the perovskite layer doped with Br in the solar cell. Scanning electron microscopy observation showed a different behavior of surface morphology and the perovskite crystal structure on the TiO{sub 2} mesoporous structure depending on extent amount of hydrogen doping of Br. The role of bromide halogen doping on the perovskite crystal structure and photovoltaic properties was due to improvement of carrier mobility, optimization of electron structure, band gap related with the photovoltaic parameters of V{sub oc}, J{sub sc} and η. Energy diagram and photovoltaic mechanism of the perovskite solar cells varied with halogen doping was discussed by experimental results.

  12. Visible light photocatalytic degradation of dyes by β-Bi{sub 2}O{sub 3}/graphene nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xuefu [College of Petrochemical Technology, Lanzhou University of Technology, Lanzhou 730050 (China); State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050 (China); Dai, Jianfeng, E-mail: jfdai1963@sohu.com [State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050 (China); Shi, Gaofeng; Li, Lan; Wang, Guoying [College of Petrochemical Technology, Lanzhou University of Technology, Lanzhou 730050 (China); Yang, Hua [State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050 (China)

    2015-11-15

    β-Bi{sub 2}O{sub 3} nanoparticles with an average grain size of 100 nm were synthesized by a polyacrylamide sol–gel method. Their bandgap energy is obtained by ultraviolet–visible diffuse reflectance spectroscopy is 2.37 eV. β-Bi{sub 2}O{sub 3}/GR composites were fabricated by mixing β-Bi{sub 2}O{sub 3} nanoparticles and graphene into absolute ethanol solution followed by thermal drying. A transmission electron microscopy observation shows that β-Bi{sub 2}O{sub 3} nanoparticles are well assembled onto GR sheets. The photocatalytic activity of prepared samples was evaluated by degrading methylene blue under the irradiation of visible light. Compared to bare β-Bi{sub 2}O{sub 3} nanoparticles, β-Bi{sub 2}O{sub 3}/GR composites exhibit significantly enhanced photocatalytic activity. Detected by the photoluminescence technique that of using terephthalic acid as a probe molecule, hydroxyl ({sup ·}OH) radicals are found to be produced on the irradiated β-Bi{sub 2}O{sub 3}/GR composites. Based on the experimental results, {sup ·}OH radicals are suggested to be the major active species which is responsible for the degradation reaction. - Highlights: • The β-Bi{sub 2}O{sub 3}/graphene composites were prepared by an ultrasound assisted method. • The visible light activity of β-Bi{sub 2}O{sub 3}/graphene was evaluated by degrading methylene blue. • The β-Bi{sub 2}O{sub 3}/graphene composites exhibit significantly enhanced photocatalytic activity. • The {sup ·}OH radicals are suggested to be the major active species.

  13. Particle characteristics and reduction behavior of synthetic magnetite

    Energy Technology Data Exchange (ETDEWEB)

    Ramadan, Wegdan [Physics Department, Faculty of Science, Alexandria University, Alexandria 21511 (Egypt); Zaki, Mohamed I., E-mail: mizaki@link.net [Chemistry Department, Faculty of Science, Minia University, El-Minia 61519 (Egypt); Fouad, Nasr E.; Mekhemer, Gamal A.H. [Chemistry Department, Faculty of Science, Minia University, El-Minia 61519 (Egypt)

    2014-04-15

    Two samples (S1 and S2) of magnetite were synthesized, using two different methods, and characterized by means of X-ray powder diffractometry, infrared and Mössbauer spectroscopy, N{sub 2} sorptiometry and electron microscopy. Particles of sample-S1 were found to be loosely agglomerated, micro-sized spheroids (200–350 nm) composed almost solely of highly aggregated (fused) crystallites (size averaged at 35 nm) of cubic-Fe{sub 3}O{sub 4}. In contrast, particles of sample-S2 were strongly agglomerated, nano-sized spheroids (25–30 nm) composed of slightly aggregated crystallites (size averaged at 11 nm) of cubic-Fe{sub 3}O{sub 4} and noncrystalline domains made-up of FeO(OH) species. Temperature-programed reduction (TPR) profiles obtained for the two samples were similar in monitoring two peaks at >450 °C assignable to a two-step reduction of Fe{sub 3}O{sub 4} (→FeO→Fe), but different in monitoring a peak at<450 °C only for the reduction of FeO(OH) (→Fe{sub 3}O{sub 4}) contained in sample-S2. However, curve fitting analysis of the TPR profiles and molecular stoichiometry calculations based on amounts of hydrogen consumed revealed that the two-step reduction of Fe{sub 3}O{sub 4} is not straightforward. That is by resolving two consecutive pathways for each step and, hence, nonstoichiometric intermediate products whose composition was found to be critically controlled by the composition of the reducing gas atmosphere (5 or 80% H{sub 2}/N{sub 2}) and characteristics of the starting sample particles (chemical and phase composition, and, but to lesser extents, the agglomeration and average size). - Highlights: • Nano or micro, pure Fe{sub 3}O{sub 4} particles are H{sub 2}-reduced in two steps (→FeO→Fe) at >450 °C. • FeO(OH)-impure particles exhibit a third reduction step (FeO(OH)→Fe{sub 3}O{sub 4}) at <450 °C. • FeO disproportion and related autocatalytic effects complicate the reduction course. • Consequently, each of the Fe{sub 3}O{sub 4

  14. First-principles optical calculations of AsNMg{sub 3} and SbNMg{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Okoye, C.M.I. [Department of Physics and Astronomy, University of Nigeria, Nsukka (Nigeria)]. E-mail: okoyecmi@yahoo.com

    2006-06-15

    The structural, electronic and optical properties of antiperovskite semiconductors AsNMg{sub 3} and SbNMg{sub 3} have been studied using the full-potential augmented plane wave plus local-orbital (APW+lo) method. The exchange correlation has been treated using the generalized gradient approximation (GGA). The equilibrium lattice constant and other structural properties have been determined. The AsNMg{sub 3} is found to be a direct band gap semiconductor while SbNMg{sub 3} is indirect. The results for electronic band structures, density of states, charge densities as well as optical properties are presented and discussed.

  15. Voltage-controlled ferromagnetism and magnetoresistance in LaCoO{sub 3}/SrTiO{sub 3} heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Chengqing; Park, Keun Woo; Yu, Edward T. [Microelectronics Research Center, The University of Texas at Austin, 10100 Burnet Rd., Austin, Texas 78758 (United States); Posadas, Agham; Demkov, Alexander A. [Department of Physics, The University of Texas at Austin, 1 University Station C1600, Austin, Texas 78712 (United States); Jordan-Sweet, Jean L. [IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598 (United States)

    2013-11-14

    A LaCoO{sub 3}/SrTiO{sub 3} heterostructure grown on Si (001) is shown to provide electrically switchable ferromagnetism, a large, electrically tunable magnetoresistance, and a vehicle for achieving and probing electrical control over ferromagnetic behavior at submicron dimensions. Fabrication of devices in a field-effect transistor geometry enables application of a gate bias voltage that modulates strain in the heterostructure via the converse piezoelectric effect in SrTiO{sub 3}, leading to an artificial inverse magnetoelectric effect arising from the dependence of ferromagnetism in the LaCoO{sub 3} layer on strain. Below the Curie temperature of the LaCoO{sub 3} layer, this effect leads to modulation of resistance in LaCoO{sub 3} as large as 100%, and magnetoresistance as high as 80%, both of which arise from carrier scattering at ferromagnetic-nonmagnetic interfaces in LaCoO{sub 3}. Finite-element numerical modeling of electric field distributions is used to explain the dependence of carrier transport behavior on gate contact geometry, and a Valet-Fert transport model enables determination of spin polarization in the LaCoO{sub 3} layer. Piezoresponse force microscopy is used to confirm the existence of piezoelectric response in SrTiO{sub 3} grown on Si (001). It is also shown that this structure offers the possibility of achieving exclusive-NOR logic functionality within a single device.

  16. A comparative study on structural, vibrational, dielectric and magnetic properties of microcrystalline BiFeO{sub 3}, nanocrystalline BiFeO{sub 3} and core–shell structured BiFeO{sub 3}@SiO{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Chauhan, Sunil; Kumar, Manoj, E-mail: mkumar.phy@gmail.com; Chhoker, Sandeep; Katyal, S.C.

    2016-05-05

    The manifestation of dimensionalities and SiO{sub 2} shell induced modifications in structural, vibrational, dielectric and magnetic properties of microcrystalline, nanocrystalline BiFeO{sub 3} and core–shell structured BiFeO{sub 3}@SiO{sub 2} nanoparticles are reported. Transmission electron microscopy image confirmed the core–shell structure of BiFeO{sub 3}@SiO{sub 2} nanoparticles with BiFeO{sub 3} core ∼50–90 nm and SiO{sub 2} shell ∼16 nm. X-ray diffraction and Raman spectroscopy results show the presence of distorted rhombohedral structure with R3c space group in all samples. Bond valance sum (BVS) calculations shows the SiO{sub 2} shell includes very small compressive stress of Bi–O and increases tensile stress of the Fe–O bonds in comparison with BiFeO{sub 3} nanoparticles. SiO{sub 2} shell on BiFeO{sub 3} nanoparticles reduces the dielectric constant and loss in comparison with microcrystalline and nanocrystalline BiFeO{sub 3} samples. The magnetic measurement indicated the existence of room-temperature weak ferromagnetism in BiFeO{sub 3} and core–shell BiFeO{sub 3}@SiO{sub 2} nanoparticles, whereas bulk BiFeO{sub 3} showed antiferromagnetic nature (almost paramagnetic in nature), which is also endorsed by second order Raman modes. The influence of the grain boundary specific area (S{sub GB}) on ferromagnetism in microcrystalline and nanocrystalline BiFeO{sub 3} samples has been deciphered. - Highlights: • BiFeO{sub 3}@SiO{sub 2} core–shell nanoparticles were prepared by Stöber process. • Detailed structural studies are done by Rietveld analysis. • Improvement magnetic properties are predicted by two phonon Raman modes. • Ferromagnetic and paramagnetic contributions are separated from total magnetization. • SiO{sub 2} shell on BiFeO{sub 3} nanoparticles reduces the dielectric constant and loss.

  17. Thermal Stabilization of {sup 233}UO{sub 2}, {sup 233}UO{sub 3}, and {sup 233}U{sub 3}O{sub 8}

    Energy Technology Data Exchange (ETDEWEB)

    Thein, S.M.

    2000-07-26

    This report identifies an appropriate thermal stabilization temperature for {sup 233}U oxides. The temperature is chosen principally on the basis of eliminating moisture and other residual volatiles. This report supports the U. S. Department of Energy (DOE) Standard for safe storage of {sup 233}U (DOE 2000), written as part of the response to Recommendation 97-1 of the Defense Nuclear Facilities Safety Board (DNFSB), addressing safe storage of {sup 233}U. The primary goals in choosing a stabilization temperature are (1) to ensure that the residual volatiles content is less than 0.5 wt % including moisture, which might produce pressurizing gases via radiolysis during long-term sealed storage; (2) to minimize potential for water readsorption above the 0.5 wt % threshold; and (3) to eliminate reactive uranium species. The secondary goals are (1) to reduce potential future chemical reactivity and (2) to increase the particle size thereby reducing the potential airborne release fraction (ARF) under postulated accident scenarios. The prevalent species of uranium oxide are the chemical forms UO{sub 2}, UO{sub 3}, and U{sub 3}O{sub 8}. Conversion to U{sub 3}O{sub 8} is sufficient to accomplish all of the desired goals. The preferred storage form is U{sub 3}O{sub 8} because it is more stable than UO{sub 2} or UO{sub 3} in oxidizing atmospheres. Heating in an oxidizing atmosphere at 750 C for at least one hour will achieve the thermal stabilization desired.

  18. Generation of Co{sub 3}O{sub 4} microparticles by solution combustion method and its Zn-Co{sub 3}O{sub 4} composite thin films for corrosion protection

    Energy Technology Data Exchange (ETDEWEB)

    Chandrappa, K.G. [Department of P.G. Studies and Research in Chemistry, School of Chemical Sciences, Jnana Sahyadri Campus, Kuvempu University, Shankaraghatta 577451, Karnataka (India); Venkatesha, T.V., E-mail: drtvvenkatesha@yahoo.co.uk [Department of P.G. Studies and Research in Chemistry, School of Chemical Sciences, Jnana Sahyadri Campus, Kuvempu University, Shankaraghatta 577451, Karnataka (India)

    2012-11-25

    Graphical abstract: The pseudo-cubic cobalt oxide microparticles have been successfully synthesized by a solution combustion method using Co(NO{sub 3}){sub 2}{center_dot}6H{sub 2}O (oxidizer) and dextrose (sugar; fuel). The as-synthesized Co{sub 3}O{sub 4} microparticles are crystalline and Rietveld refinement of calcined samples exhibited cubic structure with space group of Fm3m (No. 227). The generated Co{sub 3}O{sub 4} microparticles were used to fabricate Zn-Co{sub 3}O{sub 4} composite thin films for corrosion protection. Highlights: Black-Right-Pointing-Pointer Synthesis of pseudo-cubic Co{sub 3}O{sub 4} microparticles by solution combustion method. Black-Right-Pointing-Pointer As-prepared Co{sub 3}O{sub 4} compounds are calcined and structurally characterized. Black-Right-Pointing-Pointer Prepared Co{sub 3}O{sub 4} are utilized for the fabrication of Zn-Co{sub 3}O{sub 4} composite thin films. - Abstract: Microcrystalline cobalt oxide (Co{sub 3}O{sub 4}) powder was successfully synthesized by a simple, fast, economical and eco-friendly solution-combustion method. The as-synthesized powder was calcined for an hour at temperatures ranging from 100 to 900 Degree-Sign C. The crystallite size, morphology, and chemical state of synthesized powders were characterized by powder XRD, TG-DTA, XPS, SEM/EDAX, TEM and FT-IR spectral methods. The as-synthesized Co{sub 3}O{sub 4} powder was single-crystalline and Rietveld refinement of calcined samples exhibited cubic structure with space group of Fm3m (No. 227). The effect of calcination temperature on crystallite size and morphology was assessed. Scanning electron micrographs show a uniform, randomly oriented pseudo-cubic particle with porous like morphology and EDAX measurement showed its chemical composition. Thermal behavior of as-synthesized compound was examined. The TEM result revealed that, the particles are pseudo-cubic in nature with diameter of 0.2-0.6 {mu}m and a length of 0.9-1.2 {mu}m. The crystallite size

  19. Synthesis of LaCoO{sub 3} nano-powders by aqueous gel-casting for intermediate temperature solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Chia Siang; Zhang, Lan; Jiang, San Ping [School of Mechanical and Aerospace Engineering, Nanyang Technological University (Singapore); Zhang, Yu.Jun [Key Lab for Liquid Structure and Heredity of Ministry of Education, School of Materials Science and Engineering, Shandong University, Jinan (China)

    2008-04-15

    LaCoO{sub 3} (LC) perovskite powders for intermediate temperature solid oxide fuel cells (IT-SOFCs) are synthesized by a simple and cost-effective aqueous gel-casting technique using metal nitrates as raw materials. Effect of the ratio of organic precursors (acrylamide (AM) monomer and N,N'-Methylenebisacrylamide (MBAM) crosslinker) to metal nitrates (lanthanum nitrate, cobalt nitrate) and the ratio of AM to MBAM on the particle size are investigated in detail. TEM results indicate that the particle size of LC nano-powders is in the range of 31-60 nm and decreases with increasing ratio of organic precursor to metal nitrates but is not affected by the ratio of AM to MBAM. Preliminary results show that the nano-structured electrode approach based on wet impregnation is effective to combine the high electrocatalytic activity of LC nano-powders and the structural stability of La{sub 0.72}Sr{sub 0.18}MnO{sub 3} {sub -} {sub {delta}} (LSM) electrodes for the development of IT-SOFC cathodes. (author)

  20. Rapid extraction of uranium from sea water using Fe{sub 3}O{sub 4} and humic acid coated Fe{sub 3}O{sub 4} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Singhal, Pallavi, E-mail: psinghal@barc.gov.in [Homi Bhabha National Institute, Mumbai 400094 (India); Health Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Jha, Sanjay K. [Homi Bhabha National Institute, Mumbai 400094 (India); Health Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Pandey, Shailaja P. [Analytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Neogy, Suman [Mechanical Metallurgy Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2017-08-05

    Highlights: • Uranium extraction using Fe{sub 3}O{sub 4} and HA coated Fe{sub 3}O{sub 4} NPs has been demonstrated. • Result indicates uranium extraction from both water and sea water matrix. • With increase in HA coating uranium extraction increases. • Fe{sub 3}O{sub 4}/HA 1 is the best material among synthesized one for uranium extraction. - Abstract: Uranium is one of the most toxic elements present in the environment and a number of methods have been developed for its extraction. Herein we have demonstrated a new method using magnetic nanoparticles (NPs) that can be used for uranium extraction from water and sea water matrix. Fe{sub 3}O{sub 4} and humic acid (HA) coated Fe{sub 3}O{sub 4} NPs with different amount of HA coating were synthesized and uranium sorption from water and sea water matrix was demonstrated. It was observed that sorption increases with increase in amount of HA coating. NPs settlement in presence of magnetic field was monitored where only bare Fe{sub 3}O{sub 4} and Fe{sub 3}O{sub 4}/HA 1 NPs settles while no settlement was observed for Fe{sub 3}O{sub 4}/HA 2 and Fe{sub 3}O{sub 4}/HA 3 NPs. Considering both sorption and particle separation from the matrix Fe{sub 3}O{sub 4}/HA 1 NPs are the best among synthesized ones with maximum sorption capacity of 10.5 mg of U/g of NPs. The results presented here reveal the exceptional potential of magnetic NPs and functionalized magnetic NPs for environmental remediation of uranium and to extract uranium from sea water on which to the best of our knowledge no report is available till now.

  1. Dielectric and magnetic properties of Ta sub 2 O sub 5 -doped PrFeO sub 3 -PbTiO sub 3 and PrFeO sub 3 -BiFeO sub 3 ceramics

    CERN Document Server

    Kim, J S; Choi, Y N; Jang, P W

    2003-01-01

    Polarization-electric field (P-E) and magnetization-magnetic field (M-H) hysteresis curves have been characterized in the solid solutions of (1-x)PrFeO sub 3 -xPbTiO sub 3 +yTa sub 2 O sub 5 (y = 0-0.015 mole) and 0.2PrFeO sub 3 -0.8BiFeO sub 3. Neutron and X-ray diffraction data were collected for crystal structural analysis. The (1-x)PrFeO sub 3 -xPbTiO sub 3 were ferromagnetic at 0.2 = 0.7 from Pbnm (a = 5.552, b = 5.540 A, c = 7.833 A) to I4cm (a = b = 5.54 A, c = 7.841A) The structural analysis indicates that the solid solutions are ferroelectric only at x > 0.6. The 0.2PrFeO sub 3 -0.8BiFeO sub 3 showed a spontaneous magnetization of 0.3 emu/g at room temperature and remanent polarization P sub r of 0.6 mu C/cm sup 2. Addition of Ta sub 2 O sub 5 substantially changed the magnetic properties. The antiferromagnetic ordering is considered not to have a direct relationship with the weak ferromagnetism observed in this system. (author)

  2. Direct synthesis of Sr{sub 3}Al{sub 2}(OH){sub 12} from solution for preparation of fine-grained Sr{sub 3}Al{sub 2}O{sub 6} phosphors at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Jianquan, E-mail: jianquanqi@mail.tsinghua.edu.cn [School of Nature Resources & Materials Science, Northeastern University at Qinhuangdao, Qinhuangdao, Hebei Province 066004 (China); Zhang, Xinyi [School of Chemistry, Monash University, Clayton, Victoria 3800 (Australia); Han, Xiumei [School of Nature Resources & Materials Science, Northeastern University at Qinhuangdao, Qinhuangdao, Hebei Province 066004 (China); Li, Yuanyuan; Wu, Xueyang [School of Chemistry, Monash University, Clayton, Victoria 3800 (Australia); Zhong, Ruixia; Guo, Rui [School of Nature Resources & Materials Science, Northeastern University at Qinhuangdao, Qinhuangdao, Hebei Province 066004 (China)

    2016-09-05

    The precursors Sr{sub 3}Al{sub 2}(OH){sub 12} can be directly precipitated from solution near room temperature under the normal pressure. The cubic Sr{sub 3}Al{sub 2}O{sub 6} with fine grain size can be synthesized from Sr{sub 3}Al{sub 2}(OH){sub 12} at the temperature as low as 600 °C. Especially, the rare earth element, such as Eu{sup 3+} etc., as luminescent center, has been simultaneously integrated into the lattices of Sr{sub 3}Al{sub 2}O{sub 6}. The luminescent intensities of the samples annealed at a temperature over 800 °C are strong enough for phosphors, and increase with the annealing temperatures, reach a maximum at 1200 °C and then drop down at 1300 °C. The grain sizes of all the samples annealed below 1200 °C are smaller than 1 μm and suitable for mixing with other phosphors in the applications. The photoluminescent spectra of the Sr{sub 3}Al{sub 2}O{sub 6}:Eu{sup 3+} reveal that the intensities of both emission and excitation peaks increase with the dose of Eu{sup 3+}, and reach maxima at the dose level about 1.2%, then decrease due to concentration quenching. A new excitation band at 230 nm has been observed in heavier doped samples due to the complex point defects produced by association. - Graphical abstract: A novel strategy to prepare a stable hydroxide Sr{sub 3}Al{sub 2}(OH){sub 12} is developed. The strontium aluminates phosphors Eu{sup 3+} doped Sr{sub 3}Al{sub 2}O{sub 6} phosphors with controlled composition can been obtained at a low temperature by using Sr{sub 3}Al{sub 2}(OH){sub 12} as a precursor. - Highlights: • Sr{sub 3}Al{sub 2}(OH){sub 12} can be directly deposited from solution. • Sr{sub 3}Al{sub 2}O{sub 6} can be synthesized from Sr{sub 3}Al{sub 2}(OH){sub 12} at the temperature as low as 600 °C. • Luminescent center integrated into the lattices of Sr{sub 3}Al{sub 2}O{sub 6} at low temperature. • The phosphors with fine grain size and the strong luminescent intensities. • A new excitation band at 230 nm has been

  3. Production of Hydrogen by Oxidative Reforming of Diesel Fuel over Co and Ru-Co/La{sub 2}O{sub 3} catalysts derived from perovskite precursors

    Energy Technology Data Exchange (ETDEWEB)

    Navarro, R.M.; Alvarez-Galvan, M.C.; Villoria de la Mano, J.A.; Fierro, J.L.G. [Instituto de Catalisis y Petroleoquimica (CSIC), Marie Curie n 2 28049 Cantoblanco Madrid (Spain); Rosa [Centro de experimentacion de El Arenosillo (CEDEA) - Instituto Nacional de Tecnica Aerospacial (INTA) Ctra de San Juan del Puerto-Matalascanas km 31 21130 Mazagon-Moguer, Huelva (Spain)

    2006-07-01

    Oxidative reforming of diesel was studied over Co and Ru-Co/La{sub 2}O{sub 3} catalysts derived from LaCoO{sub 3} perovskite precursor. Physicochemical characterization by XPS, TPR and XRD showed that inc