Study of the fast inversion recovery pulse sequence. With reference to fast fluid attenuated inversion recovery and fast short TI inversion recovery pulse sequence

International Nuclear Information System (INIS)

Tsuchihashi, Toshio; Maki, Toshio; Suzuki, Takeshi

1997-01-01

The fast inversion recovery (fast IR) pulse sequence was evaluated. We compared the fast fluid attenuated inversion recovery (fast FLAIR) pulse sequence in which inversion time (TI) was established as equal to the water null point for the purpose of the water-suppressed T 2 -weighted image, with the fast short TI inversion recovery (fast STIR) pulse sequence in which TI was established as equal to the fat null point for purpose of fat suppression. In the fast FLAIR pulse sequence, the water null point was increased by making TR longer. In the FLAIR pulse sequence, the longitudinal magnetization contrast is determined by TI. If TI is increased, T 2 -weighted contrast improves in the same way as increasing TR for the SE pulse sequence. Therefore, images should be taken with long TR and long TI, which are longer than TR and longer than the water null point. On the other hand, the fat null point is not affected by TR in the fast STIR pulse sequence. However, effective TE was affected by variation of the null point. This increased in proportion to the increase in effective TE. Our evaluation indicated that the fast STIR pulse sequence can control the extensive signals from fat in a short time. (author)

TiO2-coated Hollow Glass Microspheres with Superhydrophobic and High IR-reflective Properties Synthesized by a Soft-chemistry Method.

Science.gov (United States)

Wong, Yinting; Zhong, Dan; Song, Aotian; Hu, Yan

2017-04-26

This manuscript proposes a soft-chemistry method to develop superhydrophobic and highly IR-reflective hollow glass microspheres (HGM). The anatase TiO2 and a superhydrophobic agent were coated on the HGM surface in one step. TBT and PFOTES were selected as the Ti source and the superhydrophobic agent, respectively. They were both coated on the HGM, and after the hydrothermal process, the TBT turned to anatase TiO2. In this way, a PFOTES/TiO2-coated HGM (MCHGM) was prepared. For comparison, PFOTES single-coated HGM (F-SCHGM) and TiO2 single-coated HGM (Ti-SCHGM) were synthesized as well. The PFOTES and TiO2 coatings on the HGM surface were demonstrated through X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive detector (EDS) characterizations. The MCHGM showed a higher contact angle (153°) but a lower sliding angle (16°) than F-SCHGM, with a contact angle of 141.2° and a sliding angle of 67°. In addition, both Ti-SCHGM and MCHGM displayed similar IR reflectivity values, which were about 5.8% higher than the original HGM and F-SCHGM. Also, the PFOTES coating barely changed the thermal conductivity. Therefore, F-SCHGM, with a thermal conductivity of 0.0479 W/(m·K), was quite like the original HGM, which was 0.0475 W/(m·K). MCHGM and Ti-SCHGM were also similar. Their thermal conductivity values were 0.0543 W/(m·K) and 0.0543 W/(m·K), respectively. The TiO2 coating slightly increased the thermal conductivity, but with the increase in reflectivity, the overall heat-insulation property was enhanced. Finally, since the IR-reflecting property is provided by the HGM coating, if the coating is fouled, the reflectivity decreases. Therefore, with the superhydrophobic coating, the surface is protected from fouling, and its lifetime is also prolonged.

Effects of TiB2 Particle and Short Fiber Sizes on the Microstructure and Properties of TiB2-Reinforced Composite Coatings

Science.gov (United States)

Lin, Yinghua; Yao, Jianhua; Wang, Liang; Zhang, Qunli; Li, Xueqiao; Lei, Yongping; Fu, Hanguang

2018-03-01

In this study, particle and short fiber-reinforced titanium matrix composite coatings are prepared via laser in situ technique using (0.5 and 50 μm) TiB2 and Ti powder as cladding materials. The microstructure and properties of the composite coatings are studied, and the changing mechanism of the microstructure is discussed. The results reveal that particle agglomeration is prone to appear with using fine TiB2 particles. Decomposition of the particles preferentially occurs with using coarse TiB2 particles. The cracks and pores on the surface of the coating are formed at a lower laser energy density. With the increase in the laser energy density, cracking on the surface of the coating diminishes, but the coating exhibits depression behavior. The depression extent of the coating using fine TiB2 particle as the reinforcement is much less than that of the coating using coarse TiB2 particle. Moreover, the size of the aggregate and the tendency of cracking can be reduced with the increase in Ti addition. Meanwhile, short TiB fiber bundles are formed by the diffusion mechanism of rod aggregate, and randomly oriented TiB short fibers are formed mainly by the dissolution-precipitation mechanism of fine TiB2 particles. Moreover, the growth of short TiB fibers can be in an alternating manner between B27 and Bf structures. The micro-hardness and wear resistance of the coatings are evidently higher than that of the titanium alloy substrate. The wear resistance of the large size TiB2 coating is higher than that of the small size TiB2 coating under the condition of low load.

Characterisation and behaviour of Ti/TiO2/noble metal anodes

International Nuclear Information System (INIS)

Gueneau de Mussy, Jean-Paul; Macpherson, Julie V.; Delplancke, Jean-Luc

2003-01-01

The morphology, composition and the electrical and electrochemical behaviour of the anodic microporous layer, prepared by the galvanostatic anodisation of Ti after sparking, followed by galvanostatic deposition of Pt or Ir have been investigated. These electrodes are proposed to function as dimensionally stable anodes (DSAs). For Ti/TiO 2 /Pt electrodes, Pt is deposited within some of the micropores of the oxide film. In contrast, for Ti/TiO 2 /Ir, the metal is deposited preferentially on the top surface. This difference is thought to result from the position of the metal deposition potential with respect to the flat band potential of n-TiO 2 . Optical imaging of both types of DSA suggests that only a few sites on the surface are responsible for electron exchange at the DSA-electrolyte interface. C-AFM measurements of Ti/TiO 2 /Pt samples subjected to long-term anodic polarisation, suggest that the Ti-noble metal contact is progressively insulated by thickening of the TiO 2 barrier layer, promoting passivation of the DSA. For Ir coated anodes, catalytic activity is directly related to the presence of Ir and to the stability of the catalytic oxide layer. Under Cu electrowinning conditions, the electrochemically formed hydrated Ir oxide was found to be catalytically less stable, than the iridium oxide film subjected to a heat treatment

IR emission and electrical conductivity of Nd/Nb-codoped TiO{sub x} (1.5 < x < 2) thin films grown by pulsed-laser deposition

Energy Technology Data Exchange (ETDEWEB)

Tchiffo-Tameko, C.; Cachoncinlle, C. [GREMI, UMR 7344 CNRS-Université Orléans, 45067 Orléans Cedex 2 (France); Perriere, J. [Sorbonne Universités, UPMC Université Paris 06, UMR 7588, INSP, 75005 Paris (France); CNRS, UMR 7588, INSP, 75005 Paris (France); Nistor, M. [NILPRP, L 22 P.O. Box MG-36, 77125 Bucharest-Magurele (Romania); Petit, A.; Aubry, O. [GREMI, UMR 7344 CNRS-Université Orléans, 45067 Orléans Cedex 2 (France); Pérez Casero, R. [Departamento de Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Millon, E., E-mail: eric.millon@univ-orleans.fr [GREMI, UMR 7344 CNRS-Université Orléans, 45067 Orléans Cedex 2 (France)

2016-12-15

Highlights: • Nd/Nb-codoped TiO{sub 2} PLD films are electrically insulating and transparent in the UV visible NIR spectral domain. • Nd/Nb-codoped oxygen deficient TiO{sub x} (x ≈ 1.5) films are conductive and absorbent. • IR emission of Nd{sup 3+} in codoped TiO{sub x} films is quenched due to oxygen deficiency. • High Nb-doping rate decreases the IR emission of Nd{sup 3+} in Nd/Nb-codoped TiO{sub 2} films. - Abstract: The effect of the co-doping with Nd and Nb on electrical and optical properties of TiO{sub x} films is reported. The role of oxygen vacancies on the physical properties is also evidenced. The films are grown by pulsed-laser deposition onto (001) sapphire and (100) silicon substrates. The substrate temperature was fixed at 700 °C. To obtain either stoichiometric (TiO{sub 2}) or highly oxygen deficient (TiO{sub x} with x < 1.6) thin films, the oxygen partial pressure was adjusted at 10{sup −1} and 10{sup −6} mbar, respectively. 1%Nd-1%Nb, 1%Nd-5%Nb and 5%Nd-1%Nb co-doped TiO{sub 2} were used as bulk ceramic target. Composition, structural and morphological properties of films determined by Rutherford backscattering spectroscopy, X-ray diffraction and scanning electron microscopy, are correlated to their optical (UV–vis transmission and photoluminescence) and electrical properties (resistivity at room temperature). The most intense Nd{sup 3+} emission in the IR domain is obtained for stoichiometric films. Codoping Nd-TiO{sub x} films by Nb{sup 5+} ions is found to decrease the photoluminescence efficiency. The oxygen pressure during the growth allows to tune the optical and electrical properties: insulating and highly transparent (80% in the visible range) Nd/Nb codoped TiO{sub 2} films are obtained at high oxygen pressure, while conductive and absorbent films are grown under low oxygen pressure (10{sup −6} mbar).

Performance Limits and IR Design Challenges of a Possible LHC Luminosity Upgrade Based on Nb-Ti SC Magnet Technology

CERN Document Server

Brüning, Oliver Sim; Ostojic, R; Rossi, L; Ruggiero, F; Scandale, Walter; Taylor, T

2004-01-01

We investigate the maximum LHC performance for a standard IR design based on classical NbTi insertion magnets. We include in our analysis a ternary Nb-based ductile allow such as NbTi(Ta), a less developed but relatively cheap superconducting material which may allow to gain about 1 T in the peak field in the coils, and discuss the corresponding luminosity reach for a possible LHC upgrade compared to that based on Nb$_{3}$Sn magnets.

In situ study of interface reactions of ion beam sputter deposited (Ba0.5Sr0.5)TiO3 films on Si, SiO2, and Ir

International Nuclear Information System (INIS)

Gao, Y.; Mueller, A.H.; Irene, E.A.; Auciello, O.; Krauss, A.; Schultz, J.A.

1999-01-01

(Ba 0.5 ,Sr 0.5 )TiO 3 (BST) thin films were deposited on MgO, Si, SiO 2 and Ir surfaces by ion beam sputter deposition in oxygen at 700 degree C. In situ spectroscopic ellipsometry (SE) has been used to investigate the evolution of the BST films on different surfaces during both deposition and postannealing processes. First, the optical constants of the BST films in the photon energy range of 1.5 - 4.5 eV were determined by SE analysis on crystallized BST films deposited on MgO single crystal substrates. The interfaces in BST/Si and BST/SiO 2 /Si structure were examined by SE and Auger electron spectroscopy depth profiles. Subcutaneous oxidation in the BST/Ir structure was observed by in situ SE during both ion beam sputter deposition and postdeposition annealing in oxygen at 700 degree C. A study of the thermal stability of the Ir/TiN/SiO 2 /Si structure in oxygen at 700 degree C was carried out using in situ SE. The oxidation of Ir was confirmed by x-ray diffraction. The surface composition and morphology evolution after oxidation were investigated by time of flight mass spectroscopy of recoiled ions (TOF-MSRI) and atomic force microscopy. It has been found that Ti from the underlying TiN barrier layer diffused through the Ir layer onto the surface and thereupon became oxidized. It was also shown that the surface roughness increases with increasing oxidation time. The implications of the instability of Ir/TiN/SiO 2 /Si structure on the performance of capacitor devices based on this substrate are discussed. It has been shown that a combination of in situ SE and TOF-MSRI provides a powerful methodology for in situ monitoring of complex oxide film growth and postannealing processes. copyright 1999 American Vacuum Society

Complete titanium substitution by boron in a tetragonal prism: exploring the complex boride series Ti(3-x)Ru(5-y)Ir(y)B(2+x) (0 ≤ x ≤ 1 and 1 theory.

Science.gov (United States)

Fokwa, Boniface P T; Hermus, Martin

2011-04-18

Polycrystalline samples and single crystals of four members of the new complex boride series Ti(3-x)Ru(5-y)Ir(y)B(2+x) (0 ≤ x ≤ 1 and 1 X-ray diffraction as well as energy- and wavelength-dispersive X-ray spectroscopy analyses. They crystallize with the tetragonal Ti(3)Co(5)B(2) structure type in space group P4/mbm (No. 127). Tetragonal prisms of Ru/Ir atoms are filled with titanium in the boron-poorest phase (Ti(3)Ru(2.9)Ir(2.1)B(2)). Gradual substitution of titanium by boron then results in the successive filling of this site by a Ti/B mixture en route to the complete boron occupation, leading to the boron-richest phase (Ti(2)Ru(2.8)Ir(2.2)B(3)). Furthermore, both ruthenium and iridium share two sites in these structures, but a clear Ru/Ir site preference is found. First-principles density functional theory calculations (Vienna ab initio simulation package) on appropriate structural models (using a supercell approach) have provided more evidence on the stability of the boron-richest and -poorest phases, and the calculated lattice parameters corroborate very well with the experimentally found ones. Linear muffin-tin orbital atomic sphere approximation calculations further supported these findings through crystal orbital Hamilton population bonding analyses, which also show that the Ru/Ir-B and Ru/Ir-Ti heteroatomic interactions are mainly responsible for the structural stability of these compounds. Furthermore, some stable and unstable phases of this complex series could be predicted using the rigid-band model. According to the density of states analyses, all phases should be metallic conductors, as was expected from these metal-rich borides.

Preparation of Ti/IrO2 Anode with Low Iridium Content by Thermal Decomposition Process: Electrochemical removal of organic pollutants in water

Science.gov (United States)

Yaqub, Asim; Isa, Mohamed Hasnain; Ajab, Huma; Kutty, S. R. M.; Ezechi, Ezerie H.; Farooq, Robina

2018-04-01

In this study IrO2 (Iridium oxide) was coated onto a titanium plate anode from a dilute (50 mg/10 ml) IrCl3×H2O salt solution. Coating was done at high temperature (550∘C) using thermal decomposition. Surface morphology and characteristics of coated surface of Ti/IrO2 anode were examined by FESEM and XRD. The coated anode was applied for electrochemical removal of organic pollutants from synthetic water samples in 100 mL compartment of batch electrochemical cell. About 50% COD removal was obtained at anode prepared with low Ir content solution while 72% COD removal was obtained with anode prepared at high Ir content. Maximum COD removal was obtained at 10 mA/cm2 current density.

Computational modelling of Ti50Pt50-xMx shape memory alloys (M: Ni, Ir or Pd and x = 6.25-43.75 at.%)

CSIR Research Space (South Africa)

Modiba, Rosinah M

2017-09-01

Full Text Available The ab initio density functional theory approach was employed to study the effect of Ni, Ir or Pd addition to the TiPt shape memory alloy. The supercell approach in VASP was used to substitute Pt with 6.25, 18.75, 25.00, 31.25 and 43.75 at.% Ni, Ir...

Asmens duomenų apsaugos ir žodžio laisvės konfliktas elektroninėje viešojoje erdvėje. Teisės būti pamirštam atvejis

OpenAIRE

Maslauskaitė, Judita

2018-01-01

Žodžio laisvė yra viena iš bene seniausiai pripažintų ir konstituciškai saugomų fundamentalių žmogaus teisių pasauliniu lygmeniu. Šiandienos demokratijų kontekste būtų sunku įsivaizduoti visuomenę, neturinčią teisės kalbėti, laisvai ir nuo niekieno nepriklausomai reikšti savo mintis bei idėjas. Pats žodžio laisvės konceptas buvo socialiai konstruojamas dar nuo amžių prieš Kristų, kuomet žodžio laisvė buvo prilyginama vyrų teisei laisvai kalbėti politinėmis temomis. Atsiradus ir plėtojantis pi...

Characterization of Pb(Zr, Ti)O3 thin films fabricated by plasma enhanced chemical vapor deposition on Ir-based electrodes

International Nuclear Information System (INIS)

Lee, Hee-Chul; Lee, Won-Jong

2002-01-01

Structural and electrical characteristics of Pb(Zr, Ti)O 3 (PZT) ferroelectric thin films deposited on various Ir-based electrodes (Ir, IrO 2 , and Pt/IrO 2 ) using electron cyclotron resonance plasma enhanced chemical vapor deposition were investigated. On the Ir electrode, stoichiometric PZT films with pure perovskite phase could be obtained over a very wide range of processing conditions. However, PZT films prepared on the IrO 2 electrode contain a large amount of PbO x phases and exhibited high Pb-excess composition. The deposition characteristics were dependent on the behavior of PbO molecules on the electrode surface. The PZT thin film capacitors prepared on the Ir bottom electrode showed different electrical properties depending on top electrode materials. The PZT capacitors with Ir, IrO 2 , and Pt top electrodes showed good leakage current characteristics, whereas those with the Ru top electrode showed a very high leakage current density. The PZT capacitor exhibited the best fatigue endurance with an IrO 2 top electrode. An Ir top electrode provided better fatigue endurance than a Pt top electrode. The PZT capacitor with an Ir-based electrode is thought to be attractive for the application to ferroelectric random access memory devices because of its wide processing window for a high-quality ferroelectric film and good polarization, fatigue, and leakage current characteristics

Proposal of a postal system for Ir-192 sources calibration used in high dose rate brachytherapy with LiF:Mn:Ti thermoluminescent dosemeters

International Nuclear Information System (INIS)

Vieira, W.S.; Borges, J.C.; Almeida, C.E.V.

1998-01-01

A proposal in order to improve the brachytherapy quality control and to allow postal intercomparison of Ir-192 sources used in high dose rate brachytherapy has been presented. The LiF: Mn: Ti (TLD 100) detector has been selected for such purpose. The experimental array and the TLDs irradiation and calibration techniques, at the treatment units, have been specified in the light of more recent methodology of Ir-192 calibration sources. (Author)

Density functional study of the L10-αIrV transition in IrV and RhV

International Nuclear Information System (INIS)

Mehl, Michael J.; Hart, Gus L.W.; Curtarolo, Stefano

2011-01-01

Research highlights: → The computational determination of the ground state of a material can be a difficult task, particularly if the ground state is uncommon and so not found in usual databases. In this paper we consider the alpha-IrV structure, a low temperature structure found only in two compounds, IrV and RhV. In both cases this structure can be considered as a distorted tetragonal structure, and the tetragonal 'L1 0 ' structure is the high temperature structure for both compounds. We show, however, that the logical path for the transition from the L1 0 to the alpha-IrV structure is energetically forbidden, and find a series of unstable and metastable structures which have a lower energy than the L1 0 phase, but are higher in energy than the alpha-IrV phase. We also consider the possibility of the alpha-IrV structure appearing in neighboring compounds. We find that both IrTi and RhTi are candidates. - Abstract: Both IrV and RhV crystallize in the αIrV structure, with a transition to the higher symmetry L1 0 structure at high temperature, or with the addition of excess Ir or Rh. Here we present evidence that this transition is driven by the lowering of the electronic density of states at the Fermi level of the αIrV structure. The transition has long been thought to be second order, with a simple doubling of the L1 0 unit cell due to an unstable phonon at the R point (0 1/2 1/2). We use first-principles calculations to show that all phonons at the R point are, in fact, stable, but do find a region of reciprocal space where the L1 0 structure has unstable (imaginary frequency) phonons. We use the frozen phonon method to examine two of these modes, relaxing the structures associated with the unstable phonon modes to obtain new structures which are lower in energy than L1 0 but still above αIrV. We examine the phonon spectra of these structures as well, looking for instabilities, and find further instabilities, and more relaxed structures, all of which have

Evaluation of a setting reaction pathway in the novel composite TiHA-CSD bone cement by FT-Raman and FT-IR spectroscopy

Science.gov (United States)

Paluszkiewicz, Czesława; Czechowska, Joanna; Ślósarczyk, Anna; Paszkiewicz, Zofia

2013-02-01

The aim of this study was to determine a setting reaction pathway in a novel, surgically handy implant material, based on calcium sulfate hemihydrate (CSH) and titanium doped hydroxyapatite (TiHA). The previous studies confirmed superior biological properties of TiHA in comparison to the undoped hydroxyapatite (HA) what makes it highly attractive for future medical applications. In this study the three types of titanium modified HA powders: untreated, calcined at 800 °C, sintered at 1250 °C and CSH were used to produce bone cements. The Fourier Transform-InfraRed (FT-IR) spectroscopy and Raman spectroscopy were applied to evaluate processes taking place during the setting of the studied materials. Our results undoubtedly confirmed that the reaction pathways and the phase compositions differed significantly for set cements and were dependent on the initial heat treatment of TiHA powder. Final materials were multiphase composites consisting of calcium sulfate dihydrate, bassanite, tricalcium phosphate, hydroxyapatite and calcium titanate (perovskite). The FT-IR and Scanning Electron Microscopy (SEM) measurements performed after the incubation of the cement samples in the simulated body fluid (SBF), indicate on high bioactive potential of the obtained bone cements.

HIDROGENACIÓN DE CROTONALDEHÍDO SOBRE CATALIZADORES Ir/TiO2-SiO2

Directory of Open Access Journals (Sweden)

HUGO ROJAS

2009-01-01

Full Text Available Se estudió la hidrogenación de crotonaldehído en fase líquida, sobre catalizadores Ir/TiO2-SiO2; este aldehído es altamente contaminante y proviene de fuentes tan diversas como humo de tabaco, gases de escape de motores de gasolina o diesel y humo de combustión de madera [1]. El objetivo principal de esta investigación fue la obtención del alcohol insaturado (crotil alcohol. A partir de los estudios realizados logró demostrarse que un aumento en el contenido de TiO2, lo mismo que la reducción de los catalizadores a altas temperaturas favorece parámetros como selectividad hacia el producto de interés, actividad catalítica y en general se logró mejorar de manera notable los niveles de conversión. El comportamiento observado se atribuyó principalmente a la fuerte influencia del efecto SMSI (Strong Metal Support Interaction, presente a altas temperaturas en óxidos parcialmente reducibles.

Investigation of energy band alignments and interfacial properties of rutile NMO2/TiO2 (NM = Ru, Rh, Os, and Ir) by first-principles calculations.

Science.gov (United States)

Yang, Chen; Zhao, Zong-Yan

2017-11-08

In the field of photocatalysis, constructing hetero-structures is an efficient strategy to improve quantum efficiency. However, a lattice mismatch often induces unfavorable interfacial states that can act as recombination centers for photo-generated electron-hole pairs. If the hetero-structure's components have the same crystal structure, this disadvantage can be easily avoided. Conversely, in the process of loading a noble metal co-catalyst onto the TiO 2 surface, a transition layer of noble metal oxides is often formed between the TiO 2 layer and the noble metal layer. In this article, interfacial properties of hetero-structures composed of a noble metal dioxide and TiO 2 with a rutile crystal structure have been systematically investigated using first-principles calculations. In particular, the Schottky barrier height, band bending, and energy band alignments are studied to provide evidence for practical applications. In all cases, no interfacial states exist in the forbidden band of TiO 2 , and the interfacial formation energy is very small. A strong internal electric field generated by interfacial electron transfer leads to an efficient separation of photo-generated carriers and band bending. Because of the differences in the atomic properties of the components, RuO 2 /TiO 2 and OsO 2 /TiO 2 hetero-structures demonstrate band dividing, while RhO 2 /TiO 2 and IrO 2 /TiO 2 hetero-structures have a pseudo-gap near the Fermi energy level. Furthermore, NMO 2 /TiO 2 hetero-structures show upward band bending. Conversely, RuO 2 /TiO 2 and OsO 2 /TiO 2 hetero-structures present a relatively strong infrared light absorption, while RhO 2 /TiO 2 and IrO 2 /TiO 2 hetero-structures show an obvious absorption edge in the visible light region. Overall, considering all aspects of their properties, RuO 2 /TiO 2 and OsO 2 /TiO 2 hetero-structures are more suitable than others for improving the photocatalytic performance of TiO 2 . These findings will provide useful information

Proposal of a postal system for Ir-192 sources calibration used in high dose rate brachytherapy with LiF:Mn:Ti thermoluminescent dosemeters; Proposta de um sistema postal para a calibracao de fontes de {sup 192} Ir, utilizadas em braquiterapia de alta taxa de dose, com dosimetros termoluminescentes de LiF: Mn: Ti

Energy Technology Data Exchange (ETDEWEB)

Vieira, W.S.; Borges, J.C.; Almeida, C.E.V. [Instituto de Radioprotecao e Dosimetria. CNEN Caixa Postal 37750, 22780-160, Rio de Janeiro (Brazil)

1998-12-31

A proposal in order to improve the brachytherapy quality control and to allow postal intercomparison of Ir-192 sources used in high dose rate brachytherapy has been presented. The LiF: Mn: Ti (TLD 100) detector has been selected for such purpose. The experimental array and the TLDs irradiation and calibration techniques, at the treatment units, have been specified in the light of more recent methodology of Ir-192 calibration sources. (Author)

Kinetic study of formic acid oxidation on Ti/IrO{sub 2} electrodes prepared using the spin coating deposition technique

Energy Technology Data Exchange (ETDEWEB)

Fierro, Stephane, E-mail: stephane.fierro@epfl.c [Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology, ISIC-EPFL, CH-1015 Lausanne (Switzerland); Comninellis, Christos [Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology, ISIC-EPFL, CH-1015 Lausanne (Switzerland)

2010-09-30

In the first part of this paper, IrO{sub 2} electrodes produced by thermal decomposition of H{sub 2}IrCl{sub 6} precursor were manufactured using the spin coating deposition technique, where centrifugal forces spread the precursor solution with simultaneous evaporation of the solvent on the rotating Ti substrate. It was found using this technique, that it is possible to obtain thin and uniform IrO{sub 2} coatings with controlled loadings. The influence of the concentration of iridium salt in the precursor solution (c{sub 0}) as well as the influence of the rotation speed at which the substrate spins ({omega}) on the IrO{sub 2} loading have been studied using voltammetric charge measurements. From these results, a simple relation has been proposed for the estimation of the IrO{sub 2} loading for a given c{sub 0} and {omega}. In the second part of this paper and from measurements performed using different IrO{sub 2} loadings and formic acid concentrations, the kinetic parameters of the oxidation of formic acid have been quantitatively determined using a model that involves the redox couple IrO{sub 3}/IrO{sub 2} as mediator of this reaction. Furthermore, using the kinetic parameters obtained together with the Nernst equation and the I-V curves of the supporting electrolyte (1 M HClO{sub 4}), theoretical I-V curves could be constructed for different concentrations of formic acid and different IrO{sub 2} loadings.

Microstructure Characteristic of In-situ Ti/TiC Composites

Institute of Scientific and Technical Information of China (English)

无

2001-01-01

TiC reinforced titanium composites has been produced with different Al content and C content by XDTM. The results have shown that TiC particles are of two different morphologies: coarse dendritical primary TiC and short bar-shape eutectic TiC. Al content has great effects on the morphology of TiC. With the increasing of Al content, the morphology of primary TiC changes from coarse developed dendrite into short bar-shape or plate-shape TiC with 35%Al. Meanwhile, the structure of the matrix changes from single Ti to Ti and Ti3Al, and to Ti3Al and TiAl. However, the C content has no influence on the microstructure of matrix. When the C content is less than 1.2%, the dendrite TiC disappears and only short bar-shape or plate-shape TiC exists in the composites. In addition, the effect of heat treatment on the morphology of TiC has also studied.

Highly efficient indoor air purification using adsorption-enhanced-photocatalysis-based microporous TiO2 at short residence time.

Science.gov (United States)

Lv, Jinze; Zhu, Lizhong

2013-01-01

A short residence time is a key design parameter for the removal of organic pollutants in catalyst-based indoor air purification systems. In this study, we synthesized a series of TiO2 with different micropore volumes and studied their removal efficiency of indoor carbonyl pollutants at a short residence time. Our results indicated that the superior adsorption capability of TiO2 with micropores improved its performance in the photocatalytic degradation of cyclohexanone, while the photocatalytic removal of the pollutant successfully kept porous TiO2 from becoming saturated. When treated with 1 mg m(-3) cyclohexanone at a relatively humidity of 18%, the adsorption amount on microporous TiO2 was 5.4-7.9 times higher than that on P25. Removal efficiency via photocatalysis followed'the same order as the adsorption amount: TiO2-5 > TiO2-20 > TiO2-60 > TiO2-180 > P25. The advantage of microporous TiO2 over P25 became more pronounced when the residence time declined from 0.072 to 0.036 s. Moreover, as the concentration of cyclohexanone deceased from 1000 ppb to 500 ppb, removal efficiency by microporous TiO2 increased more rapidly than P25.

Addition of IrO2 to RuO2+TiO2 coated anodes and its effect on electrochemical performance of anodes in acid media

Directory of Open Access Journals (Sweden)

Farhad Moradi

2014-04-01

Full Text Available Ternary mixed metal oxide coatings with the nominal composition IrxRu(0.6−xTi0.4O2 (x=0, 0.1, 0.2, 0.3 on the titanium substrate were prepared by thermal decomposition of a chloride precursor mixture. Surface morphology and microstructure of the coatings were investigated by Scanning electron microscopy (SEM, Field emission scanning electron microscopy (FE-SEM and X-ray diffraction (XRD analysis. Systematic study of electrochemical properties of these coatings was performed by cyclic voltammetry (CV and polarization measurements. The corrosion behavior of the coatings was evaluated under accelerated conditions (j=2 A cm−2 in acidic electrolyte. The role of iridium oxide admixture in the change of electrocatalytic activity and stability of Ru0.6Ti0.4O2 coating was discussed. Small addition of IrO2 can improve the stability of the RuO2+TiO2 mixed oxide, while the electrocatalytic activity for oxygen evolution reaction (OER is decreased. The shift of redox potentials for Ru0.6Ti0.4O2 electrode that is slightly activated with IrO2 and improvement in the stability can be attributed to the synergetic effect of mixed oxide formation.

Phosphorus doped TiO2 as oxygen sensor with low operating temperature and sensing mechanism

International Nuclear Information System (INIS)

Han, Zhizhong; Wang, Jiejie; Liao, Lan; Pan, Haibo; Shen, Shuifa; Chen, Jianzhong

2013-01-01

Nano-scale TiO 2 powders doped with phosphorus were prepared by sol–gel method. The characterization of the materials was performed by XRD, BET, FT-IR spectroscopy, Zeta potential measurement and XPS analysis. The results indicate that the phosphorus suppresses the crystal growth and phase transformation and, at the same time, increases the surface area and enhances the sensitivity and selectivity for the P-doped TiO 2 oxygen sensors. In this system, the operating temperature is low, only 116 °C, and the response time is short. The spectra of FT-IR and XPS show that the phosphorus dopant presents as the pentavalent-oxidation state in TiO 2 , further phosphorus can connect with Ti 4+ through the bond of Ti-O-P. The positive shifts of XPS peaks indicate that electron depleted layer of P-doped TiO 2 is narrowed compared with that of pure TiO 2 , and the results of Zeta potential illuminate that the density of surface charge carrier is intensified. The adsorptive active site and Lewis acid characteristics of the surface are reinforced by phosphorus doping, where phosphorus ions act as a new active site. Thus, the sensitivity of P-doped TiO 2 is improved, and the 5 mol% P-doped sample has the optimal oxygen sensing properties.

Electronic structure, local magnetism, and spin-orbit effects of Ir(IV)-, Ir(V)-, and Ir(VI)-based compounds

Energy Technology Data Exchange (ETDEWEB)

Laguna-Marco, M. A.; Kayser, P.; Alonso, J. A.; Martínez-Lope, M. J.; van Veenendaal, M.; Choi, Y.; Haskel, D.

2015-06-01

Element- and orbital-selective x-ray absorption and magnetic circular dichroism measurements are carried out to probe the electronic structure and magnetism of Ir 5d electronic states in double perovskite Sr2MIrO6 (M = Mg, Ca, Sc, Ti, Ni, Fe, Zn, In) and La2NiIrO6 compounds. All the studied systems present a significant influence of spin-orbit interactions in the electronic ground state. In addition, we find that the Ir 5d local magnetic moment shows different character depending on the oxidation state despite the net magnetization being similar for all the compounds. Ir carries an orbital contribution comparable to the spin contribution for Ir4+ (5d(5)) and Ir5+ (5d(4)) oxides, whereas the orbital contribution is quenched for Ir6+ (5d(3)) samples. Incorporation of a magnetic 3d atom allows getting insight into the magnetic coupling between 5d and 3d transition metals. Together with previous susceptibility and neutron diffractionmeasurements, the results indicate that Ir carries a significant local magnetic moment even in samples without a 3d metal. The size of the (small) net magnetization of these compounds is a result of predominant antiferromagnetic interactions between local moments coupled with structural details of each perovskite structure

Electrochemical oxidation of tetracycline antibiotics using a Ti/IrO2 anode for wastewater treatment of animal husbandry.

Science.gov (United States)

Miyata, M; Ihara, I; Yoshid, G; Toyod, K; Umetsu, K

2011-01-01

In animal husbandry, antibiotics are widely used to treat and prevent diseases or to promote growth. The use of antibiotics for domestic animals enables to promote safety of livestock products and enhance productivity. Tetracycline antibiotics (TCs) are one of the primarily used groups of antibiotics for cattle and swine. However, the unintentional spreading of antibiotics from animal waste to the environment may leave out drug residues, promoting resistant strains of bacteria, and will adversely affect the ecosystem and human health. To prevent the spread of veterinary antibiotics in the environment, it is required to treat residual antibiotics in livestock wastewater. In this study, we investigated the electrochemical oxidation of TCs to treat livestock wastewater. The concentrations of TCs in aqueous solutions were reduced from 100 mg/L to less than 0.6 mg/L by 6 h of electrochemical treatment using a Ti/IrO2 anode with Na2SO4 electrolyte. The concentration of oxytetracycline (OTC) in livestock wastewater was also reduced from 100 mg/L to less than 0.7 mg/L by the same treatment. Thus, the electrochemical oxidation using a Ti/IrO2 anode with Na2SO4 electrolyte was found to be effective for degradation of TCs. The results suggest that the electrochemical oxidation method is a promising treatment for TCs in livestock wastewater.

VO2 /TiN Plasmonic Thermochromic Smart Coatings for Room-Temperature Applications.

Science.gov (United States)

Hao, Qi; Li, Wan; Xu, Huiyan; Wang, Jiawei; Yin, Yin; Wang, Huaiyu; Ma, Libo; Ma, Fei; Jiang, Xuchuan; Schmidt, Oliver G; Chu, Paul K

2018-03-01

Vanadium dioxide/titanium nitride (VO 2 /TiN) smart coatings are prepared by hybridizing thermochromic VO 2 with plasmonic TiN nanoparticles. The VO 2 /TiN coatings can control infrared (IR) radiation dynamically in accordance with the ambient temperature and illumination intensity. It blocks IR light under strong illumination at 28 °C but is IR transparent under weak irradiation conditions or at a low temperature of 20 °C. The VO 2 /TiN coatings exhibit a good integral visible transmittance of up to 51% and excellent IR switching efficiency of 48% at 2000 nm. These unique advantages make VO 2 /TiN promising as smart energy-saving windows. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A short literature survey on iron and cobalt ion doped TiO2 thin films and photocatalytic activity of these films against fungi

International Nuclear Information System (INIS)

Tatlıdil, İlknur; Bacaksız, Emin; Buruk, Celal Kurtuluş; Breen, Chris; Sökmen, Münevver

2012-01-01

Highlights: ► Co or Fe doped TiO 2 thin films were prepared by sol–gel method. ► We obtained lower E g values for Fe-doped and Co-TiO 2 thin films. ► Doping greatly affected the size and shape of the TiO 2 nanoparticles. ► Photocatalytic killing effect of the doped TiO 2 thin films on C. albicans and A. niger was significantly higher than undoped TiO 2 thin film for short exposure periods. - Abstract: In this study, a short recent literature survey which concentrated on the usage of Fe 3+ or Co 2+ ion doped TiO 2 thin films and suspensions were summarized. Additionally, a sol–gel method was used for preparation of the 2% Co or Fe doped TiO 2 thin films. The surface of the prepared materials was characterised using scanning-electron microscopy (SEM) combined with energy dispersive X-ray (EDX) analysis and band gap of the films were calculated from the transmission measurements that were taken over the range of 190 and 1100 nm. The E g value was 3.40 eV for the pure TiO 2 , 3.00 eV for the Fe-doped TiO 2 film and 3.25 eV for Co-TiO 2 thin film. Iron or cobalt doping at lower concentration produce more uniformed particles and doping greatly affected the size and shape of the TiO 2 nanoparticles. Photocatalytic killing effect of the 2% Co doped TiO 2 thin film on Candida albicans was significantly higher than Fe doped TiO 2 thin film for short and long exposure periods. Doped thin films were more effective on Aspergillus niger for short exposure periods.

Įvairialyčiai lantano ir mangano oksido ir multiferoinio bismuto ferito heterodariniai

Directory of Open Access Journals (Sweden)

Bonifacas VENGALIS

2011-11-01

Full Text Available Pastaruoju metu naujų elektronikos prietaisų gamyboje buvo pasiekta didelė pažanga auginant, tyrinėjant ir pritaikant plonasluoksnes struktūras, sudarytas iš įvairių daugiakomponenčių funkcinių oksidų. Šiai oksidų grupei priklauso superlaidieji kupratai, mangano oksidai (manganitai, pasižymintys magnetovaržos reiškiniu, taip pat kiti feromagnetiniai, feroelektriniai, multiferoiniai oksidai. Manganitams (jų bendra formulė Ln1-xAxMnO3, kur Ln = La, Nd,..., o A - dvivalentis katijonas, toks kaip Ba, Sr ar Ca skiriama daug dėmesio dėl jų įdomių elektrinių savybių bei tinkamumo įvairiems spintronikos prietaisams kurti. Multiferoikai  (feroelektriniai feromagnetai pasižymi magnetoelektriniu efektu, duodančiu unikalią galimybę elektrinėms ir magnetinėms medžiagos savybėms valdyti panaudoti elektrinius ir magnetinius laukus. Bismuto feritas BiFeO3 (BFO, turintis romboedriškai deformuotą perovskito struktūrą, šiuo metu yra vienas labiausiai tyrinėjamų šios klasės junginių. Organiniai puslaidininkiai (OP taip pat atveria daug naujų galimybių elektronikai. Jų pranašumas yra didelė organinių junginių įvairovė ir palyginti paprasta ir pigi plonų sluoksnių gamybos technologija. Be to, OP pasižymi neįprastai didelėmis sukinių relaksacijos laiko vertėmis, todėl ateityje jie gali būti naudojami naujiems spintronikos prietaisams gaminti. Šiame straipsnyje apžvelgiami pastarųjų metų darbo autorių ir jų kolegų atlikti anksčiau minėtų medžiagų tyrimai. Daugiausia dėmesio skiriama magnetovaržinėmis savybėmis pasižyminčių lantano ir mangano oksidų (manganitų bei multiferoinio  BiFeO3 (BFO junginio plonųjų sluoksnių ir heterodarinių auginimui, tarpfazinių ribų tarp minėtų oksidų, laidžiojo SrTiO3 ir organinio puslaidininkio (Alq3 sudarymui, taip pat elektrinėms heterodarinių savybėms. Plonieji La2/3A1/3MnO3 (A = Ca, Sr, Ba, Ce sluoksniai, kurių storis d

Correlated electronic properties of different SrIrO{sub 3}/SrTiO{sub 3} heterostructures

Energy Technology Data Exchange (ETDEWEB)

Kraberger, Gernot J.; Aichhorn, Markus [Institute of Theoretical and Computational Physics, NAWI Graz, Graz University of Technology, Petersgasse 16, 8010 Graz (Austria)

2016-07-01

Strontium iridates are materials that combine strong electronic correlations with pronounced spin-orbit coupling, giving rise to fascinating physical properties. Strategies to purposefully influence and design these materials are a crucial step to further advance this field. A highly promising candidate for achieving this goal is the formation of heterostructures with other materials. Motivated by this quest, we perform calculations within the DFT+DMFT framework to investigate how the geometry of heterostructures of perovskite SrIrO{sub 3} with SrTiO{sub 3} influences their correlated electronic structure. We explore the differences between (001)- and (111)-stacked heterostructures, where the latter are particularly interesting because they form buckled honeycomb lattices that have non-trivial topological properties. For the (001)-heterostructures the effect of varying the thickness of the SrIrO{sub 3} layers, and thus their effective dimensionality, are studied. As an important ingredient we have to consider the effect of lattice distortions - in the form of a rotation of the oxygen cages - on the electronic correlations. We argue how the interplay of all these factors together allows a targeted modification of the electronic properties of the material.

Direct Observation of Surface Potential Distribution in Insulation Resistance Degraded Acceptor-Doped BaTiO3 Multilayered Ceramic Capacitors

Science.gov (United States)

Hong, Kootak; Lee, Tae Hyung; Suh, Jun Min; Park, Jae-Sung; Kwon, Hyung-Soon; Choi, Jaeho; Jang, Ho Won

2018-05-01

Insulation resistance (IR) degradation in BaTiO3 is a key issue for developing miniaturized multilayer ceramic capacitors (MLCCs) with high capacity. Despite rapid progress in BaTiO3-based MLCCs, the mechanism of IR degradation is still controversial. In this study, we demonstrate the Al doping effect on IR degradation behavior of BaTiO3 MLCCs by electrical measurements and scanning Kelvin probe microscopy (SKPM). As the Al doping concentration in BaTiO3 increases, IR degradation of MLCCs seems to be suppressed from electrical characterization results. However, SKPM results reveal that the conductive regions near the cathode become lager with Al doping after IR degradation. The formation of conducting regions is attributed to the migration of oxygen vacancies, which is the origin of IR degradation in BaTiO3, in dielectric layers. These results imply that acceptor doping in BaTiO3 solely cannot suppress the IR degradation in MLCC even though less asymmetric IR characteristics and IR degradation in MLCCs with higher Al doping concentration are observed from electrical characterization. Our results strongly suggest that observing the surface potential distribution in IR degraded dielectric layers using SKPM is an effective method to unravel the mechanism of IR degradation in MLCCs.

Panchromatic response composed of hybrid visible-light absorbing polymers and near-IR absorbing dyes for nanocrystalline TiO{sub 2}-based solid-state solar cells

Energy Technology Data Exchange (ETDEWEB)

Lee, Hyo Joong; Graetzel, Michael; Nazeeruddin, Md. Khaja [Laboratory for Photonics and Interfaces, Institute of Chemical Sciences and Engineering, School of Basic Sciences, Swiss Federal Institute of Technology, CH-1015 Lausanne (Switzerland); Leventis, Henry C.; Haque, Saif A. [Department of Chemistry, Imperial College of Science Technology and Medicine, London SW72AZ (United Kingdom); Torres, Tomas [Departamento de Quimica Organica, Universidad Autonoma de Madrid (UAM), 28049 Madrid (Spain)

2011-01-01

In pursuit of panchromatic sensitizers for mesoporous TiO{sub 2}-based solid-state solar cells, a near-IR absorbing zinc phthalocyanine dye (coded TT1) was firstly adsorbed over relatively thin ({proportional_to}1 {mu}m) TiO{sub 2} mesoporous films and then a visible-light absorbing polymer [regioregular poly(3-hexylthiophene), P3HT] was incorporated into the mesopores as both a second sensitizer and a solid hole conductor. After optimizing some experimental parameters, these hybrid solid-state cells exhibited a clear panchromatic response, and an overall conversion efficiency of around 1% at full sun intensity. (author)

A short literature survey on iron and cobalt ion doped TiO{sub 2} thin films and photocatalytic activity of these films against fungi

Energy Technology Data Exchange (ETDEWEB)

Tatl Latin-Small-Letter-Dotless-I dil, Ilknur [Department of Chemistry, Faculty of Science, Karadeniz Technical University, 61080 Trabzon (Turkey); Bacaks Latin-Small-Letter-Dotless-I z, Emin [Department of Physics, Faculty of Science, Karadeniz Technical University, 61080 Trabzon (Turkey); Buruk, Celal Kurtulus [Department of Microbiology, Faculty of Medicine, Karadeniz Technical University, 61080 Trabzon (Turkey); Breen, Chris [Materials and Engineering Research Institution, Sheffield Hallam University, Sheffield S1 1WB (United Kingdom); Soekmen, Muenevver, E-mail: msokmen@ktu.edu.tr [Department of Chemistry, Faculty of Science, Karadeniz Technical University, 61080 Trabzon (Turkey)

2012-03-15

Highlights: Black-Right-Pointing-Pointer Co or Fe doped TiO{sub 2} thin films were prepared by sol-gel method. Black-Right-Pointing-Pointer We obtained lower E{sub g} values for Fe-doped and Co-TiO{sub 2} thin films. Black-Right-Pointing-Pointer Doping greatly affected the size and shape of the TiO{sub 2} nanoparticles. Black-Right-Pointing-Pointer Photocatalytic killing effect of the doped TiO{sub 2} thin films on C. albicans and A. niger was significantly higher than undoped TiO{sub 2} thin film for short exposure periods. - Abstract: In this study, a short recent literature survey which concentrated on the usage of Fe{sup 3+} or Co{sup 2+} ion doped TiO{sub 2} thin films and suspensions were summarized. Additionally, a sol-gel method was used for preparation of the 2% Co or Fe doped TiO{sub 2} thin films. The surface of the prepared materials was characterised using scanning-electron microscopy (SEM) combined with energy dispersive X-ray (EDX) analysis and band gap of the films were calculated from the transmission measurements that were taken over the range of 190 and 1100 nm. The E{sub g} value was 3.40 eV for the pure TiO{sub 2}, 3.00 eV for the Fe-doped TiO{sub 2} film and 3.25 eV for Co-TiO{sub 2} thin film. Iron or cobalt doping at lower concentration produce more uniformed particles and doping greatly affected the size and shape of the TiO{sub 2} nanoparticles. Photocatalytic killing effect of the 2% Co doped TiO{sub 2} thin film on Candida albicans was significantly higher than Fe doped TiO{sub 2} thin film for short and long exposure periods. Doped thin films were more effective on Aspergillus niger for short exposure periods.

Temperature field analysis of single layer TiO2 film components induced by long-pulse and short-pulse lasers

International Nuclear Information System (INIS)

Wang Bin; Zhang Hongchao; Qin Yuan; Wang Xi; Ni Xiaowu; Shen Zhonghua; Lu Jian

2011-01-01

To study the differences between the damaging of thin film components induced by long-pulse and short-pulse lasers, a model of single layer TiO 2 film components with platinum high-absorptance inclusions was established. The temperature rises of TiO 2 films with inclusions of different sizes and different depths induced by a 1 ms long-pulse and a 10 ns short-pulse lasers were analyzed based on temperature field theory. The results show that there is a radius range of inclusions that corresponds to high temperature rises. Short-pulse lasers are more sensitive to high-absorptance inclusions and long-pulse lasers are more easily damage the substrate. The first-damage decision method is drawn from calculations.

Short range order and phase separation in Ti-rich Ti-Al alloys

International Nuclear Information System (INIS)

Liew, H.J.

1999-01-01

of the reaction over a range of scales, from the atomic level on which order occurs through to large scale precipitates. Ti-15at%Al displays a phase separation mechanism involving both ordering and chemical phase decomposition which occurs in a time and temperature range that is readily accessible experimentally. Hence this alloy is an appropriate model system on which to conduct fundamental investigations into a complex decomposition mechanism and its kinetics. Both experimental and modelling results show that short range order develops rapidly in the alloy, and is followed by the formation and growth of congruent long range ordered regions of DO 19 structure. At a later stage composition variations form and increase in amplitude through a spinodal mechanism. From these findings, it cannot be ruled out that the observed decomposition sequence is due solely to the kinetics of ordering being more rapid than those of chemical phase separation. However, there are some indications which suggest that a thermodynamic criterion is operating, such that the onset of chemical phase separation occurs only after ordering has been achieved to some extent. The observed mechanism is fully consistent in appearance with the class of reactions known as conditional spinodals. (author)

KINETIC BEHAVIOR IN THE HYDROGENATION OF FURFURAL OVER Ir CATALYSTS SUPPORTED ON TiO2

Directory of Open Access Journals (Sweden)

HUGO ROJAS

2010-01-01

Full Text Available La cinética de la hidrogenación en fase líquida de furfural a alcohol furfurilico sobre catalizadores de Ir/TiO2 se estudio en el rango de temperaturas de 323 a 373 K, también se estudio el efecto de la concentración de furfural, presión de hidrogeno y del solvente empleado. Se obtuvo una alta selectividad hacía el alcohol furfurilico. Con las velocidades iníciales de reacción se determino el orden de reacción global. Los datos experimentales pueden también explicarse usando un modelo LangmuirHinshelwood considerando un solo tipo de sitio activo con adsorción disociativa de hidrogeno, siendo la reacción superficial la etapa limitante de la reacción, este modelo se ajusta a los datos experimentales.

Temperature field analysis of single layer TiO2 film components induced by long-pulse and short-pulse lasers.

Science.gov (United States)

Wang, Bin; Zhang, Hongchao; Qin, Yuan; Wang, Xi; Ni, Xiaowu; Shen, Zhonghua; Lu, Jian

2011-07-10

To study the differences between the damaging of thin film components induced by long-pulse and short-pulse lasers, a model of single layer TiO(2) film components with platinum high-absorptance inclusions was established. The temperature rises of TiO(2) films with inclusions of different sizes and different depths induced by a 1 ms long-pulse and a 10 ns short-pulse lasers were analyzed based on temperature field theory. The results show that there is a radius range of inclusions that corresponds to high temperature rises. Short-pulse lasers are more sensitive to high-absorptance inclusions and long-pulse lasers are more easily damage the substrate. The first-damage decision method is drawn from calculations. © 2011 Optical Society of America

XPS Spectra Analysis of Ti2+, Ti3+ Ions and Dye Photodegradation Evaluation of Titania-Silica Mixed Oxide Nanoparticles

Science.gov (United States)

Chinh, Vu Duc; Broggi, Alessandra; Di Palma, Luca; Scarsella, Marco; Speranza, Giorgio; Vilardi, Giorgio; Thang, Pham Nam

2018-04-01

TiO2-SiO2 mixed oxides have been prepared by the sol-gel technique from tetrabutyl orthotitanate and tetraethyl orthosilicate. The prepared materials were characterized by x-ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy, nitrogen physisorption, Fourier-transform infrared spectroscopy (FT-IR) and x-ray photoelectron spectroscopy (XPS). The results indicate that the TiO2-SiO2 mixed oxides have a large surface area and a nanoscale size. FT-IR spectra show that Ti atoms are bonded to silica by oxygen bridging atoms in Ti-O-Si bonds. The titanium valence states in TiO2-SiO2 mixed oxides were investigated by XPS, and their spectra report the presence of Ti2+ and Ti3+ cations for high silica concentration, suggesting the formation of oxygen vacancies. The photocatalytic activity of the prepared materials has been evaluated for the photodegradation of methylene blue (MB). The mixed oxides were activated by means of a UV light source, and the concentration of MB was monitored by UV-Vis spectroscopy. The synthesized TiO2-SiO2 shows significantly higher MB removal efficiency in comparison with that of the commercial TiO2 Degussa, P25.

A study of TiB2/TiB gradient coating by laser cladding on titanium alloy

Science.gov (United States)

Lin, Yinghua; Lei, Yongping; Li, Xueqiao; Zhi, Xiaohui; Fu, Hanguang

2016-07-01

TiB2/TiB gradient coating has been fabricated by a laser cladding technique on the surface of a Ti-6Al-4V substrate using TiB2 powder as the cladding material. The microstructure and mechanical properties of the gradient coating were analyzed by SEM, EPMA, XRD, TEM and an instrument to measure hardness. With the increasing distance from the coating surface, the content of TiB2 particles gradually decreased, but the content of TiB short fibers gradually increased. Meanwhile, the micro-hardness and the elastic modulus of the TiB2/TiB coating showed a gradient decreasing trend, but the fracture toughness showed a gradient increasing trend. The fracture toughness of the TiB2/TiB coating between the center and the bottom was improved, primarily due to the debonding of TiB2 particles and the high fracture of TiB short fibers, and the fracture position of TiB short fiber can be moved to an adjacent position. However, the debonding of TiB2 particles was difficult to achieve at the surface of the TiB2/TiB coating.

HIDROGENACIÓN SELECTIVA DE CITRAL EN FASE LÍQUIDA SOBRE CATALIZADORES Ir–Fe/TiO2 REDUCIDOS A ALTA TEMPERATURA

Directory of Open Access Journals (Sweden)

Hugo Alonso Rojas Sarmiento

2008-03-01

Full Text Available En este trabajo se muestra la hidrogenación del citral sobre catalizadores de Ir e Ir-Fe/TiO2 reducidos a 773 K (HTR. Lapreparación de los catalizadores se realizó con soluciones acuosas de H2IrCl6 para obtener una carga de metal al 1% y por impregnación de FeCl3, lo cual permitió obtener los correspondientes sistemas bimetálicos. Todos los catalizadores presentaron una selectividad del 100% hacia los alcoholes insaturados (geraniol y nerol. La caracterización de los sólidos se efectuó mediante quimisorción selectiva de hidrógeno a 298 K, DRX, TPR y XPS. Los resultados de actividad intrínseca y selectividad se explican con base en los datos de caracterización que ponen en evidencia el efecto de una fuerte interacción metal-soporte (SMSI. También se muestra la descripción de un reactor tipo STR donde se efectuó la evaluación de la actividad intrínseca del catalizador.

Effects of noble-metal ion implantation on corrosion inhibition and charge injection capability of surgical Ti and Ti-6Al-4V

International Nuclear Information System (INIS)

Lee, I.S.

1989-01-01

Studies are described involving effects of noble-metal ion implantation on corrosion inhibition and charge injection capabilities of surgical Ti and Ti-6Al-4V. With surgical alloys, harmful biological responses are principally due to the type and quantity of metal ions released by the corrosion process. One approach to improve long-term biological performance involves surface modifications to significantly reduce degradation rates. With regard to surface-modifications, one of the most effective methods is through ion implantation. Results are presented for ion-implanted Au, Rh, and Ir. For the static in vitro corrosion properties, the noble-metal ion implanted Ti-6Al-4V and commercially-pure (CP) Ti were investigated in non-passivating acid and passivating saline solutions. It was postulated that during the early stages of corrosion (or during a corrosion pretreatment) the implanted noble-metal would enrich at the surface and significantly reduce subsequent corrosion rates. The observed behavior for the Ir and Rh implanted materials appeared to follow the postulated mechanism, with both initial and time-dependent improvements in corrosion resistance. However, the Au implanted material yielded early benefits, but the enhanced corrosion resistance deteriorated with time. X-ray photoelectron spectroscopy (XPS) analysis indicated that the implanted Au atoms remained as pure metallic Au, while the Ir and Rh atoms were in some oxide state, which gave the good adhesion of the Ir or Rh enriched surface to the Ti substrate. For a stimulating neural electrode, the charge density should be as large as possible to provide adequate stimulation of the nervous system while allowing for miniaturization of the electrode. Activated Ir has been known as having the highest charge injection capability of any material known

Red-IR stimulated luminescence in K-feldspar: Single or multiple trap origin?

DEFF Research Database (Denmark)

Andersen, Martin Thalbitzer; Jain, Mayank; Tidemand-Lichtenberg, Peter

2012-01-01

We investigate on the origins of the infra-red stimulated luminescence (IRSL) signals in 3 potassium feldspars based on IR-red spectroscopy (700–1050 nm) using a fiber-coupled tunable Ti:Sapphire laser, in combination with different thermal and optical (pre)treatments of the samples. We also...

CdS-sensitized TiO2 nanocorals: hydrothermal synthesis, characterization, application.

Science.gov (United States)

Mali, S S; Desai, S K; Dalavi, D S; Betty, C A; Bhosale, P N; Patil, P S

2011-10-01

Cadmium sulfide (CdS) nanoparticle-sensitized titanium oxide nanocorals (TNC) were synthesized using a two-step deposition process. The TiO(2) nanocorals were grown on the conducting glass substrates (FTO) using A hydrothermal process and CdS nanoparticles were loaded on TNC using successive ionic layer adsorption and reaction (SILAR) method. The TiO(2), CdS and TiO(2)-CdS samples were characterized by optical absorption, X-ray diffraction (XRD), FT-Raman, FT-IR, scanning electron microscopy (SEM) and contact angle. Further, their photoelectrochemical (PEC) performance was tested in NaOH, Na(2)S-NaOH-S and Na(2)S electrolytes, respectively. When CdS nanoparticles are coated on TNCs, the optical absorption is found to be enhanced and band edge is red-shifted towards visible region. The TiO(2)-CdS sample exhibits improved photoelectrochemical (PEC) performance with maximum short circuit current of (J(sc)) 1.04 mA cm(-2). After applying these TiO(2)-CdS electrodes in photovoltaic cells, the photocurrent was found to be enhanced by 2.7 and 32.5 times, as compared with those of bare CdS and TiO(2) nanocorals films electrodes respectively. Also, the power conversion efficiency of TiO(2)-CdS electrodes is 0.72%, which is enhanced by about 16 and 29 times for TiO(2), CdS samples. This journal is © The Royal Society of Chemistry and Owner Societies 2011

Large-format platinum silicide microwave kinetic inductance detectors for optical to near-IR astronomy.

Science.gov (United States)

Szypryt, P; Meeker, S R; Coiffard, G; Fruitwala, N; Bumble, B; Ulbricht, G; Walter, A B; Daal, M; Bockstiegel, C; Collura, G; Zobrist, N; Lipartito, I; Mazin, B A

2017-10-16

We have fabricated and characterized 10,000 and 20,440 pixel Microwave Kinetic Inductance Detector (MKID) arrays for the Dark-speckle Near-IR Energy-resolved Superconducting Spectrophotometer (DARKNESS) and the MKID Exoplanet Camera (MEC). These instruments are designed to sit behind adaptive optics systems with the goal of directly imaging exoplanets in a 800-1400 nm band. Previous large optical and near-IR MKID arrays were fabricated using substoichiometric titanium nitride (TiN) on a silicon substrate. These arrays, however, suffered from severe non-uniformities in the TiN critical temperature, causing resonances to shift away from their designed values and lowering usable detector yield. We have begun fabricating DARKNESS and MEC arrays using platinum silicide (PtSi) on sapphire instead of TiN. Not only do these arrays have much higher uniformity than the TiN arrays, resulting in higher pixel yields, they have demonstrated better spectral resolution than TiN MKIDs of similar design. PtSi MKIDs also do not display the hot pixel effects seen when illuminating TiN on silicon MKIDs with photons with wavelengths shorter than 1 µm.

Microstructure and properties of TiB2-TiB reinforced titanium matrix composite coating by laser cladding

Science.gov (United States)

Lin, Yinghua; Yao, Jianhua; Lei, Yongping; Fu, Hanguang; Wang, Liang

2016-11-01

TiB2 particle and TiB short fiber reinforced titanium matrix composite coatings were prepared utilizing in situ synthesized technique by laser cladding on the surface of Ti6Al4V alloy. Through the experiment, it was found that the surface of the single-track coatings appeared in the depression, but it can be improved by laser track overlapping. With the increase of laser power density, the amount of TiB short fiber was increased, and the distribution of TiB2 and TiB became more uniform from the top to bottom. The micro-hardness of TiB2/TiB coating showed a gradient decreasing trend, and the average micro-hardness of the coatings was two-fold higher than that of the substrate. Due to the strengthening effect of TiB2 particle and TiB short fiber, the wear volume loss of the center of the coating was approximately 30% less than that of the Ti-6Al-4V substrate, and the wear mechanism of the coating was mild fatigue particle detachment.

Ab initio study for the IR spectroscopy of PbTiO3 and PbZrO3, primary blocks of PbZr1‑x Ti x O3

Science.gov (United States)

Peperstraete, Yoann; Amzallag, Emilie; Tétot, Robert; Roy, Pascale

2018-05-01

PbTiO3 (PT) and PbZrO3 (PZ) are the two primary blocks of the solid solution PbZr1‑x Ti x O3 (PZT). They can be modelled in different ways; but, in order to do comparable DFT calculations on PZT, with different values of x, one must find a unique method that can be used for both PT and PZ. In particular, we want to evaluate their vibrational properties to compare them with experimental data. Density functional theory (DFT) is used to perform structure geometry optimizations and electronic structure calculations, both on low- and high-temperature phase. Then, harmonic vibrational frequencies of their low-temperature phase are determined for transverse and longitudinal optical (TO & LO) phonons. Moreover, a detailed study of the eigenvectors shows that accurate calculations are necessary to correctly interpret and understand the IR spectra. In the end, the comparison of our theoretical results with previous experimental and theoretical data confirm the strong potential of the SOGGA (second-order generalized gradient approximation) functional to correctly describe PT, PZ and, hopefully, PZT; especially their structural and vibrational properties.

Interfacial B-site atomic configuration in polar (111) and non-polar (001) SrIrO3/SrTiO3 heterostructures

Science.gov (United States)

Anderson, T. J.; Zhou, H.; Xie, L.; Podkaminer, J. P.; Patzner, J. J.; Ryu, S.; Pan, X. Q.; Eom, C. B.

2017-09-01

The precise control of interfacial atomic arrangement in ABO3 perovskite heterostructures is paramount, particularly in cases where the subsequent electronic properties of the material exhibit geometrical preferences along polar crystallographic directions that feature inevitably complex surface reconstructions. Here, we present the B-site interfacial structure in polar (111) and non-polar (001) SrIrO3/SrTiO3 interfaces. The heterostructures were examined using scanning transmission electron microscopy and synchrotron-based coherent Bragg rod analysis. Our results reveal the preference of B-site intermixing across the (111) interface due to the polarity-compensated SrTiO3 substrate surface prior to growth. By comparison, the intermixing at the non-polar (001) interface is negligible. This finding suggests that the intermixing may be necessary to mitigate epitaxy along heavily reconstructed and non-stoichiometric (111) perovskite surfaces. Furthermore, this preferential B-site configuration could allow the geometric design of the interfacial perovskite structure and chemistry to selectively engineer the correlated electronic states of the B-site d-orbital.

Interfacial B-site atomic configuration in polar (111 and non-polar (001 SrIrO3/SrTiO3 heterostructures

Directory of Open Access Journals (Sweden)

T. J. Anderson

2017-09-01

Full Text Available The precise control of interfacial atomic arrangement in ABO3 perovskite heterostructures is paramount, particularly in cases where the subsequent electronic properties of the material exhibit geometrical preferences along polar crystallographic directions that feature inevitably complex surface reconstructions. Here, we present the B-site interfacial structure in polar (111 and non-polar (001 SrIrO3/SrTiO3 interfaces. The heterostructures were examined using scanning transmission electron microscopy and synchrotron-based coherent Bragg rod analysis. Our results reveal the preference of B-site intermixing across the (111 interface due to the polarity-compensated SrTiO3 substrate surface prior to growth. By comparison, the intermixing at the non-polar (001 interface is negligible. This finding suggests that the intermixing may be necessary to mitigate epitaxy along heavily reconstructed and non-stoichiometric (111 perovskite surfaces. Furthermore, this preferential B-site configuration could allow the geometric design of the interfacial perovskite structure and chemistry to selectively engineer the correlated electronic states of the B-site d-orbital.

Influence of temperature of the short-period heat treatment on mechanical properties of the NiTi alloy

Directory of Open Access Journals (Sweden)

Jaroslav Čapek

2014-01-01

Full Text Available The equiatomic alloy of nickel and titanium, known as nitinol, possesses unique properties such as superelasticity, pseudoplasticity, shape memory, while maintaining good corrosion resistance and sufficient biocompatibility. Therefore it is used for production of various devices including surgery implants. Heat treatment of nickel-rich NiTi alloys can result in precipitation of nickel-rich phases, which strongly influence tensile and fatigue behaviour of the material.In this work we have studied influence of short-period heat treatment on tensile behaviour and fatigue life of the NiTi (50.9 at. % Ni wire intended for fabrication of surgery stents.

Thermal infrared and microwave absorbing properties of SrTiO3/SrFe12O19/polyaniline nanocomposites

International Nuclear Information System (INIS)

Hosseini, Seyed Hossein; Zamani, Parisa; Mousavi, S.Y.

2015-01-01

Graphical abstract: We have developed a new perspective of applications and properties of conducting polymers. The combination of absorption ability prepared nanocomposites in the present of PANI display a great potential in organization of shielding structures into thermal IR and microwave. Further investigations using other conducting polymers to demonstrate their capability for advance thermal IR and microwave shielding devices is under way. The application of these samples may improve the IR thermographic detection, catalysis, sensors, magnetic data storage, electromagnetic resonance wave absorption, photonic crystals, and microelectronic devices and military aspects. - Highlights: • The SrTiO 3 /SrFe 12 O 19 /PANI exhibited electric and electromagnetic properties. • The SrTiO 3 /SrFe 12 O 19 /PANI has shielding structures into thermal IR and microwave. • Increasing weight ratios and thicknesses will increase thermal IR ability. • Increasing weight ratios and thicknesses will increase microwave absorption ability. - Abstract: Polyaniline (PANI) as a unique polymer that also has electromagnetic absorption used as the substrate. In this research, SrTiO 3 was synthesized as IR absorbent and core and then SrFe 12 O 19 as microwave absorbent was prepared on SrTiO 3 via co-precipitation method as the first shell. As the next step, PANI was coated on SrTiO 3 /SrFe 12 O 19 nanoparticles via in situ polymerization by multi core–shell structures (SrTiO 3 /SrFe 12 O 19 /PANI). Nanometer size and structures of samples were measured by TEM, XRD and FTIR. Morphology of nanocomposite was showed by SEM images. The magnetic and electric properties were also performed by VSM and four probe techniques. Thermal infrared (IR) absorption and microwave reflection loss of nanocomposites were investigated at 10–40 μm and 8–12 GHz, IR and microwave frequencies, respectively. The results showed that the SrTiO 3 /SrFe 12 O 19 /PANI nanocomposites have good compatible

Preparation and characterization of Sr-Ti-hardystonite (Sr-Ti-HT nanocomposite for bone repair application

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Hossein Mohammadi

2015-07-01

Full Text Available Objective(s: Hardystonite (HT is Zn-modified silicate bioceramics with promising results for bone tissue regeneration. However, HT possesses no obvious apatite formation. Thus, in this study we incorporated Sr and Ti into HT to prepare Sr-Ti-hardystonite (Sr-Ti-HT nanocomposite and evaluated its in vitro bioactivity with the purpose of developing a more bioactive bone substitute material. Materials and methods:The HT and Sr-Ti-HT were prepared by mechanical milling and subsequent heat treatment. Calcium oxide (CaO, zinc oxide (ZnO and silicon dioxide (SiO2 (all from Merck were mixed with molar ratio of 2:1:2. The mixture of powders mixture was then milled in a planetary ball mill for 20 h. In the milling run, the ball-to-powder weight ratio was 10:1 and the rotational speed was 200 rpm. After synthesis of HT, 3% nanotitanium dioxide (TiO2, Degussa and 3% strontium carbonate (SrCO3, Merck were added to HT and then the mixture was ball milled and calcined at 1150°C for 6 h. Simultaneous thermal analysis (STA, X-ray diffraction (XRD, Transmission electron microscopy (TEM and Fourier transform infra-red spectroscopy (FT-IR performed to characterize the powders. Results:XRD and FT-IR confirmed the crystal phase and silicate structure of HT and TEM images demonstrated the nanostructure of powders. Further, Sr-Ti-HT induced apatite formation and showed a higher human mesenchymal stem cell (hMSCs adhesion and proliferation compared to HT. Conclusion:Our study revealed that Sr-Ti-HT with a nanostructured crystal structure of 50 nm, can be prepared by mechanical activation to use as biomaterials for orthopedic applications.

Preparation of SrIrO{sub 3} thin films by using metal-organic aerosol deposition technique

Energy Technology Data Exchange (ETDEWEB)

Esser, Sebastian; Schneider, Melanie; Moshnyaga, Vasily; Gegenwart, Philipp [1. Physikalisches Institut, Georg-August-Universitaet Goettingen (Germany)

2013-07-01

The interplay between spin-orbit coupling and electronic correlations could lead to interesting novel states in iridium oxide materials. We focus on the perovskite phase of SrIrO{sub 3} because Moon et al. [1] showed by using optical spectroscopy and first-principles calculations that the last member of the Ruddlesden-Popper series Sr{sub n+1}Ir{sub n}O{sub 3n+1} (n = ∞) is close to the Mott transition. By using metal-organic aerosol deposition technique we have grown SrIrO{sub 3} thin films on (111)-oriented SrTiO{sub 3} substrates. The cubic symmetry of the SrTiO{sub 3} substrate ensured that the SrIrO{sub 3} thin film grew in the monoclinic perovskite phase. The X-ray diffraction results suggest that SrIrO{sub 3} thin films in perovskite structure were obtained and these show out of plane epitaxy with monoclinic (002){sub m}-orientation. The temperature dependence of the electrical resistivity of these SrIrO{sub 3} thin films were investigated and metallic behavior was observed down to 50 K.

Tailoring the Activity for Oxygen Evolution Electrocatalysis on Rutile TiO2(110) by Transition-Metal Substitution

DEFF Research Database (Denmark)

Garcia-Mota, Monica; Vojvodic, Aleksandra; Metiu, Horia

2011-01-01

The oxygen evolution reaction (OER) on the rutile M-TiO2(110) (M = V, Nb, Ta, Cr, Mo, W, Mn, Fe, Ru, Ir, Ni) surfaces was investigated by using density functional theory calculations. The stability of different doped TiO2 systems was analyzed. The scaling relationship between the binding energies...... of OER intermediates (HOO* versus HO*) is found to follow essentially the same trend as for undoped oxides. Our theoretical analysis shows a lower overpotential associated with OER on the doped M-TiO2(110) than on the undoped TiO2(110). The theoretical activity of Cr-, Mo-, Mn-, and Ir-doped TiO2...

On the structure and normal modes of hydrogenated Ti-fullerene compounds

Energy Technology Data Exchange (ETDEWEB)

Tlahuice-Flores, Alfredo, E-mail: tlahuicef@yahoo.com [Universidad Nacional Autonoma de Mexico, Instituto de Fisica (Mexico); Mejia-Rosales, Sergio, E-mail: sergio.mejiars@uanl.edu.mx [Universidad Autonoma de Nuevo Leon, CICFIM-Facultad de Ciencias Fisico Matematicas, and Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia (Mexico); Galvan, Donald H., E-mail: donald@cnyn.unam.mx [Centro de Nanociencias y Nanotecnologia-Universidad Nacional Autonoma de Mexico (Mexico)

2012-08-15

When titanium covers a C{sub 60} core, the metal atoms may suppress the fullerene's capacity of storing hydrogen, depending on the number of Ti atoms covering the C{sub 60} framework, the Ti-C binding energy, and diffusion barriers. In this article, we study the structural and vibrational properties of the C{sub 60}TiH{sub n} (n = 2, 4, 6, and 8) and C{sub 60}Ti{sub 6}H{sub 48} compounds. The IR spectra of C{sub 60}TiH{sub n} compounds have a maximum attributable to the Ti-H stretching mode, which shifts to lower values in the structures with n = 4, 8, while their Raman spectra show two peaks corresponding to the stretching modes of H{sub 2} molecules at apical and azimuthal positions. On the other hand, the IR spectrum of C{sub 60}Ti{sub 6}H{sub 48} shows an intense peak due to the Ti-H in-phase stretching mode, while its Raman spectrum has a maximum attributed to the pentagonal pinch of the C{sub 60} core. Finally, we have found that the presence of one apical H{sub 2} molecule enhances the pentagonal pinch mode, becoming the maximum in the Raman spectrum.Graphical Abstract.

Selective hydrogenation of furfural on Ir/TiO2 catalysts

Directory of Open Access Journals (Sweden)

Patricio Reyes

2010-01-01

Full Text Available Titania-supported Ir catalysts were used in the hydrogenation of furfural. Reactions were carried out in a stirred batch type reactor at 0.62MPa and 363K using a 0.10M solution of furfural in a 1:1 mixture n-heptane -ethanol as solvent. Catalysts containing 2 wt% of Ir were reduced in H2 flow at different temperatures in the range 473-773K. The catalysts were characterized by H2 chemisorption, TEM, TPR, TPD of NH3 and XPS. Conversion of furfural is higher at lower reduction temperatures, but leads to byproducts whereas reduction at higher temperatures shows selectivity to furfuryl alcohol close to 100%.

Improvement of Short-Circuit Current Density in Dye-Sensitized Solar Cells Using Sputtered Nanocolumnar TiO2 Compact Layer

Directory of Open Access Journals (Sweden)

Lung-Chien Chen

2010-01-01

Full Text Available The effect of a nanocolumnar TiO2 compact layer in dye-sensitized solar cells (DSSCs was examined. Such a compact layer was sputtered on a glass substrate with an indium tin oxide (ITO film using TiO2 powder as the raw material, with a thickness of ~100 nm. The compact layer improved the short-circuit current density and the efficiency of conversion of solar energy to electricity by the DSSC by 53.37% and 59.34%, yielding values of 27.33 mA/cm2 and 9.21%, respectively. The performance was attributed to the effective electron pathways in the TiO2 compact layer, which reduced the back reaction by preventing direct contact between the redox electrolyte and the conductive substrate.

Insulation Resistance Degradation in Ni-BaTiO3 Multilayer Ceramic Capacitors

Science.gov (United States)

Liu, Donhang (David)

2015-01-01

Insulation resistance (IR) degradation in Ni-BaTiO3 multilayer ceramic capacitors has been characterized by the measurement of both time to failure and direct-current (DC) leakage current as a function of stress time under highly accelerated life test conditions. The measured leakage current-time dependence data fit well to an exponential form, and a characteristic growth time ?SD can be determined. A greater value of tau(sub SD) represents a slower IR degradation process. Oxygen vacancy migration and localization at the grain boundary region results in the reduction of the Schottky barrier height and has been found to be the main reason for IR degradation in Ni-BaTiO3 capacitors. The reduction of barrier height as a function of time follows an exponential relation of phi (??)=phi (0)e(exp -2?t), where the degradation rate constant ??=??o??(????/????) is inversely proportional to the mean time to failure (MTTF) and can be determined using an Arrhenius plot. For oxygen vacancy electromigration, a lower barrier height phi(0) will favor a slow IR degradation process, but a lower phi(0) will also promote electronic carrier conduction across the barrier and decrease the insulation resistance. As a result, a moderate barrier height phi(0) (and therefore a moderate IR value) with a longer MTTF (smaller degradation rate constant ??) will result in a minimized IR degradation process and the most improved reliability in Ni-BaTiO3 multilayer ceramic capacitors.

Hydrogen isotope behavior on Li2TiO3

International Nuclear Information System (INIS)

Olivares, Ryan; Oda, Takuji; Tanaka, Satoru; Oya, Yasuhisa; Tsuchiya, Kunihiko

2004-01-01

The surface nature of Li 2 TiO 3 and the adsorption behavior of water on Li 2 TiO 3 surface were studied by XPS/UPS and FT/IR. Preliminary experiments by Ar ion sputtering, heating and water exposure were conducted, and the following results were obtained. (1) By Ar sputtering, Li deficient surface was made, and Ti was reduced from Ti 4+ to Ti 3+ . (2) By heating sputtered samples over 573-673 K, Li emerged on the surface and Ti was re-oxidized to Ti 4+ . The surface -OH was removed. The valence band of Li 2 TiO 3 became similar to that of TiO 2 . (3) By water exposure at 623 K, H 2 O could be adsorbed dissociatively on the surface. LiOH was not formed. (4) The nature of Li 2 TiO 3 surface resembles that of TiO 2 , rather than Li 2 O. (author)

Robustness of dynamic magnetism in the triangle-based antiferromagnets Ba3Ru1- x Ir x Ti2O9 ( x = 0.5 and 0.8)

Science.gov (United States)

Lee, W.-J.; Do, S.-H.; Lee, S.; Choi, Y.-S.; Choi, K.-Y.; Yoon, Sungwon; Suh, Byoungjin; Jang, Zeehoon

2018-01-01

We report on the spin dynamics of the strong spin-orbit coupled antiferromagnets Ba3Ru1- x Ir x Ti2O9 ( x = 0.5 and 0.8), which comprise a mixture of edge- and corner-sharing triangles. Muon spin-relaxation measurements give no hints of long-range magnetic order down to 25 mK. Rather, the muon spin-relaxation rates λ( T) show persistent spin dynamics below 1 K, indicating that fast fluctuations are dominant in spite of Ir4+( J eff = 1/2)/Ru4+( S = 1) randomness. The muon spin depolarization of both compounds is well described by a stretched exponential function with the stretching exponent β = 0.4 (0.6) for x = 0.5 (0.8) at low temperatures, which is larger than β = 1/3 expected for a spin glass. Our results suggest that randomness in the spin number and the exchange interaction induces a partial spin freezing, but the majority of spins remain dynamically fluctuating.

Crystal structure of transition metal halides TiCl4, α-TiCl3, WCl4 and TiI2

International Nuclear Information System (INIS)

Troyanov, S.I.; Snigireva, E.M.

2000-01-01

Crystal structures of TiCl 4 , α-TiCl 3 , WCl 4 and TiI 2 are determined by x-ray diffraction method. For crystalline WCl 4 general for phases of this type space group C2/m is confirmed. Linear chains of WCl 6 octahedrons joined through the opposite edges exist in structure. Short W-W distances (2.69 A) in linear chains differentiate the structure of WCl 6 . Laminar structure of TiI 2 is belongs to CdI 2 structural type. Iodine atoms form slightly distorted hexagonal face-centered packing, titanium atoms fill up octahedral hollows in two-layer packing of iodine atoms with Ti-I distances equal 2.903 A [ru

Thermal infrared and microwave absorbing properties of SrTiO{sub 3}/SrFe{sub 12}O{sub 19}/polyaniline nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Hosseini, Seyed Hossein, E-mail: shhosseini@iiau.ac.ir [Department of Chemistry, Faculty of Science, Islamshahr Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Zamani, Parisa [Department of Applied Chemistry, Faculty of Pharmaceutical Chemistry, Pharmaceutical Sciences Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Mousavi, S.Y. [Faculty of Passive Defense, Imam Hossein University, Tehran (Iran, Islamic Republic of)

2015-09-25

Graphical abstract: We have developed a new perspective of applications and properties of conducting polymers. The combination of absorption ability prepared nanocomposites in the present of PANI display a great potential in organization of shielding structures into thermal IR and microwave. Further investigations using other conducting polymers to demonstrate their capability for advance thermal IR and microwave shielding devices is under way. The application of these samples may improve the IR thermographic detection, catalysis, sensors, magnetic data storage, electromagnetic resonance wave absorption, photonic crystals, and microelectronic devices and military aspects. - Highlights: • The SrTiO{sub 3}/SrFe{sub 12}O{sub 19}/PANI exhibited electric and electromagnetic properties. • The SrTiO{sub 3}/SrFe{sub 12}O{sub 19}/PANI has shielding structures into thermal IR and microwave. • Increasing weight ratios and thicknesses will increase thermal IR ability. • Increasing weight ratios and thicknesses will increase microwave absorption ability. - Abstract: Polyaniline (PANI) as a unique polymer that also has electromagnetic absorption used as the substrate. In this research, SrTiO{sub 3} was synthesized as IR absorbent and core and then SrFe{sub 12}O{sub 19} as microwave absorbent was prepared on SrTiO{sub 3} via co-precipitation method as the first shell. As the next step, PANI was coated on SrTiO{sub 3}/SrFe{sub 12}O{sub 19} nanoparticles via in situ polymerization by multi core–shell structures (SrTiO{sub 3}/SrFe{sub 12}O{sub 19}/PANI). Nanometer size and structures of samples were measured by TEM, XRD and FTIR. Morphology of nanocomposite was showed by SEM images. The magnetic and electric properties were also performed by VSM and four probe techniques. Thermal infrared (IR) absorption and microwave reflection loss of nanocomposites were investigated at 10–40 μm and 8–12 GHz, IR and microwave frequencies, respectively. The results showed that the SrTi

Preparation and Characterization of TiO2 Nanostructure by TiCl4 Hydrolysis with Additive NaOH

Directory of Open Access Journals (Sweden)

Rashed Taleb Rasheed

2018-04-01

Full Text Available Titanium dioxide (TiO2 nanostructures were synthesized via the hydrolysis of TiCl4 in alcohol / water solution/with sodium hydroxide solution in the ice-bath (0-5 ◦C. The particles were char-acterized by using X-ray diffraction technique (XRD, spectroscopy of Ultra Violet-Visible (UV / Visible and infrared (FT-IR, atomic force microscope (AFM and scanning electron micro-scope (SEM analysis were used in order to gain information about the material, morphology, size and the shape of the particles

Ag loading induced visible light photocatalytic activity for pervoskite SrTiO3 nanofibers

Science.gov (United States)

Wu, Yeqiu; He, Tao

2018-06-01

The synthesis and photocatalytic activities of Ag-SrTiO3 nanofibers were reported in this work. The fabricated Ag-SrTiO3 nanofibers were characterized by TG-DSC, XRD, IR, XPS, SEM, TEM, DRS and ESR techniques. The XRD and IR results show that Ag-SrTiO3 nanofibers have a perovskite structure after the heat treatment at 700 °C. The XPS result shows that Ag element exists as Ag0 in the fabricated Ag-SrTiO3 nanofibers. The SEM and TEM images indicate the obtaining of nanofibers with porous structure. The photocatalytic activity of Ag-SrTiO3 nanofibers was evaluated by degrading RhB and MB under visible light irradiation. The Ag-SrTiO3 nanofibers show excellent photocatalytic activity under visible light irradiation because of the surface plasmon resonance effect of Ag0. In the photocatalysis process of RhB and MB, lots of hydroxyl radicals were generated, which plays the key role in the decomposition of organic pollutants.

Dzimumu atšķirības otrās valodas apguvē

OpenAIRE

Brūdere, Kristīne

2012-01-01

Bakalaura darbs pēta dzimumu atšķirības otrās valodas apguvē un dzimuma ietekmi valodas apgūšanā, kas arī tika pārbaudīts praktiskajā daļā. Pētnieciskā darba mērķis ir noskaidrot kādā veidā izpaužas dzimumu atšķirības otrās valodas apguvē un kā tas ietekmē valodas apguvi. Praktiskās daļas rezultāti liecina, ka dzimumu atšķirības pastāv. Galvenās atšķirības tiek novērotas mutiskajā komunikācijā, aktivitātes ziņā, vēlmē apgūt valodu un uzsvara likšanā uz valodas apguvi. Lai arī atšķirības starp...

Anodic incineration of phthalic anhydride using RuO2–IrO2–SnO2–TiO2 coated on Ti anode

Directory of Open Access Journals (Sweden)

S. Chellammal

2016-11-01

Full Text Available Phthalic anhydride is a toxic and non-biodegradable organic compound and is widely used for the production of dyes. This paper has investigated the electrochemical oxidation of phthalic anhydride in an undivided cell at different experimental parameters such as pH, current density and supporting electrolytes on the anode of titanium substrate coated with mixed metal oxides of RuO2, IrO2, SnO2 and TiO2 prepared by thermal decomposition method. The surface morphology and the structure of the above anode were characterized by scanning electron microscopy, electron dispersion microscopy and X-ray diffraction. The study shows that the electrode exhibits good electro catalytic activity together with chemical stability during the treatment of the phthalic anhydride. At pH 3, the maximum removal of COD of 88% with energy consumption of 30.5 kW h kg−1 was achieved by the addition of 10 g l−1 NaCl in 0.2 mol dm−3 Na2SO4 at 5 Adm−2. This electrolytic investigation offers an attractive alternative method for the destruction of industrial effluents contaminated with phthalic anhydride.

Electrochemical incineration of chloranilic acid using Ti/IrO2, Pb/PbO2 and Si/BDD electrodes

International Nuclear Information System (INIS)

Martinez-Huitle, Carlos A.; Quiroz, Marco Antonio; Comninellis, Christos; Ferro, Sergio; Battisti, Achille De

2004-01-01

The electrochemical oxidation of chloranilic acid (CAA) has been studied in acidic media at Pb/PbO 2 , boron-doped diamond (Si/BDD) and Ti/IrO 2 electrodes by bulk electrolysis experiments under galvanostatic control. The obtained results have clearly shown that the electrode material is an important parameter for the optimization of such processes, deciding of their mechanism and of the oxidation products. It has been observed that the oxidation of CAA generates several intermediates eventually leading to its complete mineralization. Different current efficiencies were obtained at Pb/PbO 2 and BDD, depending on the applied current density in the range from 6.3 to 50 mA cm -2 . Also the effect of the temperature on Pb/PbO 2 and BDD electrodes was studied. UV spectrometric measurements were carried out at all anodic materials, with applied current density of 25 and 50 mA cm -2 . These results showed a faster CAA elimination at the BDD electrode. Finally, a mechanism for the electrochemical oxidation of CAA has been proposed according to the results obtained with the HPLC technique

Iridium Interfacial Stack - IrIS

Science.gov (United States)

Spry, David

2012-01-01

Iridium Interfacial Stack (IrIS) is the sputter deposition of high-purity tantalum silicide (TaSi2-400 nm)/platinum (Pt-200 nm)/iridium (Ir-200 nm)/platinum (Pt-200 nm) in an ultra-high vacuum system followed by a 600 C anneal in nitrogen for 30 minutes. IrIS simultaneously acts as both a bond metal and a diffusion barrier. This bondable metallization that also acts as a diffusion barrier can prevent oxygen from air and gold from the wire-bond from infiltrating silicon carbide (SiC) monolithically integrated circuits (ICs) operating above 500 C in air for over 1,000 hours. This TaSi2/Pt/Ir/Pt metallization is easily bonded for electrical connection to off-chip circuitry and does not require extra anneals or masking steps. There are two ways that IrIS can be used in SiC ICs for applications above 500 C: it can be put directly on a SiC ohmic contact metal, such as Ti, or be used as a bond metal residing on top of an interconnect metal. For simplicity, only the use as a bond metal is discussed. The layer thickness ratio of TaSi2 to the first Pt layer deposited thereon should be 2:1. This will allow Si from the TaSi2 to react with the Pt to form Pt2Si during the 600 C anneal carried out after all layers have been deposited. The Ir layer does not readily form a silicide at 600 C, and thereby prevents the Si from migrating into the top-most Pt layer during future anneals and high-temperature IC operation. The second (i.e., top-most) deposited Pt layer needs to be about 200 nm to enable easy wire bonding. The thickness of 200 nm for Ir was chosen for initial experiments; further optimization of the Ir layer thickness may be possible via further experimentation. Ir itself is not easily wire-bonded because of its hardness and much higher melting point than Pt. Below the iridium layer, the TaSi2 and Pt react and form desired Pt2Si during the post-deposition anneal while above the iridium layer remains pure Pt as desired to facilitate easy and strong wire-bonding to the Si

Equation of short fatigue crack growth law of 1Cr18Ni9Ti weld metal

International Nuclear Information System (INIS)

Zhao Yongxiang; Yang Bing; Gao Qing

2005-01-01

The method is investigated for characterizing the short fatigue crack (SFC) behaviour of 1Cr18Ni9Ti weld metal by the 'effective short fatigue crack criterion'. Three considerations are given. Firstly, the dominant effective short fatigue crack (DESFC) behaviour is a result of the interaction and evolution of the collective SFCs and, therefore, it is deemed suitable to describe their collective behaviour. Secondly, the significant character of microstructural short crack (MSC) regime and physical short crack (PSC) regime for the behaviour of SFCs indicates that it should be well exhibited in the characterization. Thirdly, the stronger irregular behaviour of SFCs indicates the single parameter of cyclic stress or strain amplitude for representing driving force of DESFC growth may be not appropriated. A new growth law for the collective SFCs is derived from a consideration of the local cyclic strain energy density driving the DESFC initiation in the initial zone and, then, driving the DESFC growth in the zones around its tips. The final form of this law is relative to the total cyclic strain energy density of remote fields, which circle the initial zone and, then, the zones around the DESFC tips. Availability has been indicated by an analysis of the test data of present material. (authors)

Nb$_{3}$Sn quadrupole magnets for the LHC IR

CERN Document Server

Sabbi, G L; Chiesa, L; Coccoli, M; Dietderich, D R; Ferracin, P; Gourlay, S A; Hafalia, R R; Lietzke, A F; McInturff, A D; Scanlan, R M

2003-01-01

The development of insertion quadrupoles with 205 T/m gradient and 90 mm bore represents a promising strategy to achieve the ultimate luminosity goal of 2.5 * 10/sup 34/ cm/sup -2/s/sup -1/ at the Large Hadron Collider (LHC). At present, Nb/sub 3/Sn is the only practical conductor which can meet these requirements. Since Nb/sub 3/Sn is brittle, and considerably more strain sensitive than NbTi, the design concepts and fabrication techniques developed for NbTi magnets need to be modified appropriately. In addition, IR magnets must provide high field quality and operate reliably under severe radiation loads. The results of conceptual design studies addressing these issues are presented. (25 refs).

Nb3Sn Quadrupole Magnets for the LHC IR

International Nuclear Information System (INIS)

Sabbi, G.; Caspi, S.; Chiesa, L.; Coccoli, M.; Dietderich, D.R.; Ferracin, P.; Gourlay, S.A.; Hafalia, R.R.; Lietzke, A.F.; McInturff, A.D.; Scanlan, R.M.

2001-01-01

The development of insertion quadrupoles with 205 T/m gradient and 90 mm bore represents a promising strategy to achieve the ultimate luminosity goal of 2.5 x 10 34 cm -2 s -1 at the Large Hadron Collider (LHC). At present, Nb 3 Sn is the only practical conductor which can meet these requirements. Since Nb 3 Sn is brittle, and considerably more strain sensitive than NbTi, the design concepts and fabrication techniques developed for NbTi magnets need to be modified appropriately. In addition, IR magnets must provide high field quality and operate reliably under severe radiation loads. The results of conceptual design studies addressing these issues are presented.

SEB VB Investicijų valdymas valdomų ir platinamų investicinių fondų portfelio optimizavimas

OpenAIRE

Kurlianskaitė, Rimantė; Stonienė, Lina

2007-01-01

Magistro darbe plačiai nagrinėjami H. Markowitz (1952), J. Tobin (1958), W. Sharpe (1964), S. Ross (1976), G. Fama ir K. French (1993) ir kitų autorių darbai, kuriuose akcentuojami portfelio formavimo kriterijai bei optimalaus portfelio sudarymo problemos. Darbas apima modernios portfelio teorijos praktinio pritaikymo aspektus, įvertinant vertybinių popierių atrankos į portfelį ir jų įkainojimo ypatumus bei portfelio vertę įtakojančius veiksnius, ieškant būdų jiems kiekybiškai išreikšti. Atli...

Development of TiC and TiN coated molybdenum limiter system and initial results of the thermal testing in neutral beam heated JFT-2 tokamak

International Nuclear Information System (INIS)

Nakamura, Hiroo; Sengoku, Seio; Maeno, Masaki; Yamamoto, Shin; Seki, Masahiro; Kazawa, Minoru

1982-06-01

This paper describes the limiter drive system for TiC and TiN coated molybdenum limiters and the thermal testing results of the TiC coated limiter in the JFT-2 tokamak using neutral beam injection (0.7 MW). To investigate the influence of TiC coated limiter on plasma behavior and adhesion property under tokamak plasma, a full scale limiter test has been performed in the JFT-2. Reproducible plasma was obtained after the plasma conditioning. Maximum heat flux to the limiter, measured by IR camera, was 1.5 -- 6.5 kW/cm 2 in 25 msec. Cracking, exfoliation and melting on TiC coated limiter were not observed, except for a number of arc tracks. Finally, the permissible heat fluxes of TiC coated molybdenum first wall are discussed. (author)

Synthesis and characterization of FeTiO3 ceramics

OpenAIRE

Anil B. Gambhire; Machhindra K. Lande; Sandip B. Rathod; Balasaheb R. Arbad; Kaluram N. Vidhate; Ramakrishna S. Gholap; Kashinath R. Patil

2016-01-01

Nanocrystalline FeTiO3 ceramic powders were prepared by the sol–gel process combined with a surfactant-assisted template method. The resulting powders were calcined at different temperatures ranging from 150 °C to 600 °C for 2 h in air. The results revealed that a pure hexagonal phase of FeTiO3 could be obtained at a low temperature, 600 °C. The phase evolution of FeTiO3 was investigated by X-ray diffraction patterns (XRD), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelect...

Vibrational spectra of mixed oxides of Ln2MgTiO6 composition

International Nuclear Information System (INIS)

Porotnikov, N.V.; German, M.; Kovba, L.M.

1984-01-01

In the range 33-4000 cm -1 IR and Raman spectra of complex oxides of the composition Ln 2 MgTiO 6 (Ln=La-Yb and Y) have been studied. Using the Magnesium isotope-substituted compositions Lasub(2)sup(24,26)MgTiOsub(6), Smsub(2)sup(24,26)MgTiOsub(6) and Ybsub(2)sup(24,26)MgTiOsub(6), it has been shoWn that in Ln 2 MgTiO 6 titanium and magnesium ions are located in sites With octahedral coordination, of rare earth ions highly-coordinated polyhedrons with coordination number 10-12 are characteristic

Combination of short-length TiO_2 nanorod arrays and compact PbS quantum-dot thin films for efficient solid-state quantum-dot-sensitized solar cells

International Nuclear Information System (INIS)

Zhang, Zhengguo; Shi, Chengwu; Chen, Junjun; Xiao, Guannan; Li, Long

2017-01-01

Graphical abstract: The TiO_2 nanorod array with the length of 600 nm, the diameter of 20 nm, the areal density of 500 μm"−"2 was successfully prepared. The compact PbS quantum-dot thin film was firstly obtained on the TiO_2 nanorod array by spin-coating-assisted successive ionic layer absorption and reaction with using 1,2-ethanedithiol. The photoelectric conversion efficiency (PCE) of the compact PbS quantum-dot thin film sensitized solar cells achieved 4.10% using spiro-OMeTAD as a hole transporting layer, while the PCE of the PbS quantum-dot sensitized solar cells was only 0.54%. - Highlights: • Preparation of TiO_2 nanorod arrays with the length of 600 nm, diameter of 20 nm. • The compact PbS QD thin film and short-length TiO_2 nanorod array were combined. • EDT addition improved PbS nanoparticle coverage and photovoltaic performance. • The compact PbS QD thin film sensitized solar cell achieved the PCE of 4.10%. - Abstract: Considering the balance of the hole diffusion length and the loading quantity of quantum-dots, the rutile TiO_2 nanorod array with the length of 600 nm, the diameter of 20 nm, and the areal density of 500 μm"−"2 is successfully prepared by the hydrothermal method using the aqueous grown solution of 38 mM titanium isopropoxide and 6 M hydrochloric acid at 170 °C for 105 min. The compact PbS quantum-dot thin film on the TiO_2 nanorod array is firstly obtained by the spin-coating-assisted successive ionic layer absorption and reaction with using 1,2-ethanedithiol (EDT). The result reveals that the strong interaction between lead and EDT is very important to control the crystallite size of PbS quantum-dots and obtain the compact PbS quantum-dot thin film on the TiO_2 nanorod array. The all solid-state sensitized solar cell with the combination of the short-length, high-density TiO_2 nanorod array and the compact PbS quantum-dot thin film achieves the photoelectric conversion efficiency of 4.10%, along with an open

Photoelectrochemical performance of multi-layered BiOx–TiO2/Ti electrodes for degradation of phenol and production of molecular hydrogen in water

International Nuclear Information System (INIS)

Park, Hyunwoong; Bak, Ayoung; Ahn, Yong Yoon; Choi, Jina; Hoffmannn, Michael R.

2012-01-01

Highlights: ► We demonstrated that the electrocatalytic performance of BiO x –TiO 2 anodes for the degradation of aqueous phenol could be highly boosted by light irradiation. ► Although BiO x –TiO 2 anodes have been originally developed as the electrocatalytic anodes that operate in the absence of light by degeneratively doping Bi in TiO 2 , the presence of TiO 2 made them retain photoelectrocatalytic activity as well. ► Such dual functionality of BiO x –TiO 2 electrodes with high synergy effects may be directly used for water treatment with simultaneous hydrogen production from water. - Abstract: Multi-layered BiO x –TiO 2 electrodes were used for the oxidation of chemical contaminants coupled with the production of H 2 characterized by a synergistic enhancement. The BiO x –TiO 2 electrodes were composed of a mixed-metal oxide array involving an under layer of TaO x –IrO x , a middle layer of BiO x –SnO 2 , and a top layer of BiO x –TiO 2 deposited in a series on both sides of Ti foil. Cyclic voltammograms showed that the BiO x –TiO 2 electrodes had an electrocatalytic activity for oxidation of phenol that was enhanced by 70% under illumination with AM 1.5 light. When the BiO x –TiO 2 anode was coupled with a stainless steel cathode in a Na 2 SO 4 electrolyte with phenol and irradiated with UV light at an applied DC voltage, the anodic phenol oxidation rate and the cathodic H 2 production rates were enhanced by factors of four and three, respectively, as compared to the sum of each light irradiation and direct DC electrolysis. These synergistic effects depend on the specific electrode composition and decrease on TaO x –IrO x and BiO x –SnO 2 anodes in the absence of a top layer of BiO x –TiO 2 . These results indicate that the BiO x –TiO 2 layer functions as the key photo-electrocatalyst. The heavy doping level of Bi (25 mol%) in TiO 2 increases the electric conductivity of the parent TiO 2 .

Synthesis of TiO2-doped SiO2 composite films and its applications

Indian Academy of Sciences (India)

Wintec

structure of the titanium oxide species in the TiO2-doped SiO2 composite films and the photocatalytic reactiv- ity in order to ... gaku D-max γA diffractometer with graphite mono- chromized ... FT–IR absorption spectra of TiO2-doped SiO2 com-.

Formation of hydroxyapatite on Ti-coated Ti-Zr-Cu-Pd bulk metallic glass

International Nuclear Information System (INIS)

Qin, F.X.; Wang, X.M.; Wada, T.; Xie, G.Q.; Asami, K.; Inoue, A.

2009-01-01

In this research, Ti coating was conducted on Ti 40 Zr 10 Cu 36 Pd 14 bulk metallic glass (BMG) in order to increase the formation rate of hydroxyapatite layer. The formation behavior of bone-like hydroxyapatite on Ti-coated and uncoated Ti 40 Zr 10 Cu 36 Pd 14 bulk metallic glasses (BMGs) was studied. The surface morphology of Ti-coated and uncoated Ti 40 Zr 10 Cu 36 Pd 14 BMG was investigated by scanning electron microscopy and energy dispersive X-ray spectroscopy. The results revealed that the alkali pretreatment in 5 M NaOH solution at 60degC for 24 h had a beneficial effect on the formation of porous sodium titanate on Ti-coated Ti 40 Zr 10 Cu 36 Pd 14 BMG. A bone-like hydroxyapatite layer was able to form on the alkali-treated Ti-coated Ti 40 Zr 10 Cu 36 Pd 14 BMG after a short-time immersion in simulated body fluid (SBF). On the contrary, hydroxyapatite formation was not observed on the uncoated Ti 40 Zr 10 Cu 36 Pd 14 BMG after the same chemical treatments. (author)

Summary of Test Results of MQXFS1 - The First Short Model 150 mm Aperture $Nb_3Sn$ Quadrupole for the High-Luminosity

Energy Technology Data Exchange (ETDEWEB)

Stoynev, S.; et al.

2017-01-01

The development of $Nb_3Sn$ quadrupole magnets for the High-Luminosity LHC upgrade is a joint venture between the US LHC Accelerator Research Program (LARP)* and CERN with the goal of fabricating large aperture quadrupoles for the LHC in-teraction regions (IR). The inner triplet (low-β) NbTi quadrupoles in the IR will be replaced by the stronger Nb3Sn magnets boosting the LHC program of having 10-fold increase in integrated luminos-ity after the foreseen upgrades. Previously LARP conducted suc-cessful tests of short and long models with up to 120 mm aperture. The first short 150 mm aperture quadrupole model MQXFS1 was assembled with coils fabricated by both CERN and LARP. The magnet demonstrated strong performance at the Fermilab’s verti-cal magnet test facility reaching the LHC operating limits. This paper reports the latest results from MQXFS1 tests with changed pre-stress levels. The overall magnet performance, including quench training and memory, ramp rate and temperature depend-ence, is also summarized.

OXIDACIÓN DE p -NITROFENOL USANDO TiO 2 -ADENOSINA MONOFOSFATO I OXIDATION OF p -NITROPHENOL USING TiO 2 -ADENOSIN MONOPHOSPHATE

Directory of Open Access Journals (Sweden)

Carlos F. Rivas

2018-04-01

Full Text Available The surface of TiO2 was modified with the nucleotides adenosine 3’-monophosphate (AMP’3 and Adenosine 5’-monophosphate (AMP’5. The adsorption of nucleotides was adjusted to Langmuir ́s adsorption model, determining that the optimal condition for TiO 2 modification was at neutral pH. UV-Visible Diffuse Reflectance and IR Attenuated Total Reflectance spectra show that the chemisorption of nucleotides take placed on TiO 2 anatase. The new catalysts (TiO 2 -nucleotide improved the photodegradation of p -nitrophenol in a wide range of pH as compared with the titanium dioxide precursor. Most photoactivity was generated by using the new photocatalytic in the degradation of p -nitrophenol at pH = 6, obtaining high values for the pseudo first order kinetic constant (0.0254 min -1 and 0.0244 min -1 for TiO 2 -AMP’3 and TiO 2 -AMP’5, respectively. For all pH, the trend obtained for the photodegradation was: TiO 2 -AMP ́3 @ TiO 2 -AMP’5 > TiO 2 . Langmuir-Hinshelwood kinetics shows that the contribution of the surface reac tion rate governs the oxidation of the contaminant.

Experimental bandstructure of the 5 d transition metal oxide IrO2

Science.gov (United States)

Kawasaki, Jason; Nie, Yuefeng; Uchida, Masaki; Schlom, Darrell; Shen, Kyle

2015-03-01

In the 5 d iridium oxides the close energy scales of spin-orbit coupling and electron-electron correlations lead to emergent quantum phenomena. Much research has focused on the ternary iridium oxides, e.g. the Ruddlesden-Poppers An + 1BnO3 n + 1 , which exhibit behavior from metal to antiferromagnetic insulator ground states, share common features with the cuprates, and may host a number of topological phases. The binary rutile IrO2 is another important 5 d oxide, which has technological importance for spintronics due to its large spin Hall effect and also applications in catalysis. IrO2 is expected to share similar physics as its perovskite-based cousins; however, due to bond-length distortions of the IrO6 octahedra in the rutile structure, the extent of similarities remains an open question. Here we use angle-resolved photoemission spectroscopy to perform momentum-resolved measurements of the electronic structure of IrO2 . IrO2 thin films were grown by molecular beam epitaxy on TiO2 (110) substrates using an Ir e-beam source and distilled ozone. Films were subsequently transferred through ultrahigh vacuum to a connected ARPES system. Combined with first-principles calculations we explore the interplay of spin-orbit coupling and correlations in IrO2 .

The influence of alizarin and fluorescein on the photoactivity of Ni, Pt and Ru-doped TiO2 layers

International Nuclear Information System (INIS)

Rosu, Marcela-Corina; Suciu, Ramona-Crina; Lazar, Mihaela D.; Bratu, I.

2013-01-01

Highlights: ► The Ni, Pt, Ru-doped TiO 2 materials and sensitized with alizarin and fluorescein dyes were prepared by wet chemical route. ► The samples were characterized by: UV–vis spectroscopy, spectrofluorimetry, FT/IR spectroscopy and microscopy, X-ray diffraction and N 2 physisorption measurements. ► A combined influence of the dopants and dyes was observed, leading to a beneficial effect to TiO 2 photoactivity. -- Abstract: The doping with different metal ions and sensitization with organic compounds are two well known methods used to improve the photoactivity of TiO 2 . In this respect, the metallic ions-doped TiO 2 samples were prepared by embedding Ni, Pt and Ru ions into TiO 2 crystalline network and then, each sample was sensitized with alizarin and fluorescein dyes. The qualitative evaluation of prepared TiO 2 -based materials was made by: UV–vis spectroscopy, spectrofluorimetry, FT/IR spectroscopy and microscopy, X-ray diffraction and N 2 physisorption measurements. The optoelectronic properties investigated by UV–vis spectroscopy show that the optical response of Ni-doped TiO 2 layer shifts to visible. The X-ray spectra do not show peaks of nickel, platinum and ruthenium oxide crystals or pure metals. The FT/IR spectra proved the presence of dye molecules adsorbed on titania nanoparticles surface. These results demonstrated that the studied dopants and dyes have potential to promote modified TiO 2 -based materials as good candidates to be used in photolectrocatalytic processes

Irène Jacob visits CERN

CERN Document Server

CERN Bulletin

2010-01-01

French actress Irène Jacob, the daughter of physicist Maurice Jacob, visited the ATLAS and CMS control rooms on Monday 17 May together with Italian theatre actor-director Pippo Delbono, in search of inspiration for a short film. The film will be screened at the “nuit des particules” event accompanying this year’s ICHEP.   Pippo Delbono et Irène Jacob discussing their project. “La nuit des particules” (night of the particles) is an event open to the general public that is being organised for the evening of Tuesday, 27 July, to accompany the 35th International Conference on High Energy Physics (ICHEP). ICHEP is a major highlight in every physicist’s calendar, and this year’s edition is being held in Paris from 22 to 28 July. The short film will be screened during the evening, which will include a lecture and a show at the legendary Parisian cinema Le Grand Rex, with a colossal seating capacity of 2 700 spe...

Combination of short-length TiO{sub 2} nanorod arrays and compact PbS quantum-dot thin films for efficient solid-state quantum-dot-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Zhang, Zhengguo [School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei 230009 (China); School of Chemistry and Chemical Engineering, Beifang University of Nationalities, Yinchuan 750021 (China); Shi, Chengwu, E-mail: shicw506@foxmail.com [School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei 230009 (China); Chen, Junjun; Xiao, Guannan; Li, Long [School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei 230009 (China)

2017-07-15

Graphical abstract: The TiO{sub 2} nanorod array with the length of 600 nm, the diameter of 20 nm, the areal density of 500 μm{sup −2} was successfully prepared. The compact PbS quantum-dot thin film was firstly obtained on the TiO{sub 2} nanorod array by spin-coating-assisted successive ionic layer absorption and reaction with using 1,2-ethanedithiol. The photoelectric conversion efficiency (PCE) of the compact PbS quantum-dot thin film sensitized solar cells achieved 4.10% using spiro-OMeTAD as a hole transporting layer, while the PCE of the PbS quantum-dot sensitized solar cells was only 0.54%. - Highlights: • Preparation of TiO{sub 2} nanorod arrays with the length of 600 nm, diameter of 20 nm. • The compact PbS QD thin film and short-length TiO{sub 2} nanorod array were combined. • EDT addition improved PbS nanoparticle coverage and photovoltaic performance. • The compact PbS QD thin film sensitized solar cell achieved the PCE of 4.10%. - Abstract: Considering the balance of the hole diffusion length and the loading quantity of quantum-dots, the rutile TiO{sub 2} nanorod array with the length of 600 nm, the diameter of 20 nm, and the areal density of 500 μm{sup −2} is successfully prepared by the hydrothermal method using the aqueous grown solution of 38 mM titanium isopropoxide and 6 M hydrochloric acid at 170 °C for 105 min. The compact PbS quantum-dot thin film on the TiO{sub 2} nanorod array is firstly obtained by the spin-coating-assisted successive ionic layer absorption and reaction with using 1,2-ethanedithiol (EDT). The result reveals that the strong interaction between lead and EDT is very important to control the crystallite size of PbS quantum-dots and obtain the compact PbS quantum-dot thin film on the TiO{sub 2} nanorod array. The all solid-state sensitized solar cell with the combination of the short-length, high-density TiO{sub 2} nanorod array and the compact PbS quantum-dot thin film achieves the photoelectric conversion

A characterization of persistence at short times in the WFC3/IR detector

Science.gov (United States)

Gennaro, M.; Bajaj, V.; Long, K.

2018-05-01

Persistence in the WFC3/IR detector appears to decay as a power law as a function of time elapsed since the end of a stimulus. In this report we study departures from the power law at times shorter than a few hundreds seconds after the stimulus. In order to have better short-time cadence, we use the Multiaccum (.ima) files, which trace the accumulated charge in the pixels as function of time, rather than the final pipeline products (.flt files), which instead report the electron rate estimated via a linear fit to the accumulated charge vs. time relation. We note that at short times after the stimulus, the absolute change in persistence is the strongest, thus a linear fit to the accumulated signal (the .flt values) can be a poor representation of the strongly varying persistence signal. The already observed power-law decay of the persistence signal, still holds at shorter times, with typical values of the power law index, gamma in [-0.8,-1] for stimuli that saturate the WFC3 pixels. To a good degree of approximation, a single power law is a good fit to the persistence signal decay from 100 to 5000 seconds. We also detect a tapering-off in the power-law decay at increasingly shorter times. This change in behavior is of the order of Delta Gamma 0.02 - 0.05 when comparing power-law fits performed to the persistence signal from 0 up to 250 seconds and from 0 up to 4000 seconds after the stimulus, indicating that persistence decays slightly more rapidly as time progresses. Our results may suggest that for even shorter times, not probed by our study, the WFC3 persistence signal might deviate from a single power-law model.

Optimization of three-dimensional triple IR fast spoiled gradient recalled acquisition in the steady state (FSPGR) to decrease vascular artifact at 3.0 Tesla

International Nuclear Information System (INIS)

Fujiwara, Yasuhiro; Fukuya, Yuko; Yamaguchi, Isao; Matsuda, Tsuyoshi; Ishimori, Yoshiyuki; Yamada, Kazuhiro; Kimura, Hirohiko; Miyati, Tosiaki

2006-01-01

The purpose of this study was to decrease vascular artifacts caused by the in-flow effect in three-dimensional inversion recovery prepared fast spoiled gradient recalled acquisition in the steady state (3D IR FSPGR) at 3.0 Tesla. We developed 3D triple IR (3IR) FSPGR and examined the signal characteristics of the new sequence. We have optimized scan parameters based on simulation, phantom, and in-vivo studies. As a result, optimized parameters (1st TI=600 ms, 3rd TI=500 ms) successfully have produced the vessel signal at more than 40% reduction, while gray-white matter contrast was preserved. Moreover, the reduced artifact was also confirmed by visual inspection of the in-vivo images for which this condition was used. Thus, 3D 3IR FSPGR was a useful sequence for the acquisition of T1-weighted images at 3.0 Tesla. (author)

Zr 2Ir 6B with an eightfold superstructure of the cubic perovskite-like boride ZrIr 3B 0.5: Synthesis, crystal structure and bonding analysis

Science.gov (United States)

Hermus, Martin; Fokwa, Boniface P. T.

2010-04-01

Single phase powder samples and single crystals of Zr 2Ir 6B were successfully synthesized by arc-melting the elements in a water-cooled copper crucible under an argon atmosphere. Superstructure reflections were observed both on powder and on single crystal diffraction data, leading to an eightfold superstructure of ZrIr 3B x phase. The new phase, which has a metallic luster, crystallizes in space group Fm3¯m (no. 225) with the lattice parameters a=7.9903(4) Å, V=510.14(4) Å 3. Its crystal structure was refined on the basis of powder as well as single crystal data. The single crystal refinement converged to R1=0.0239 and w R2=0.0624 for all 88 unique reflections and 6 parameters. Zr 2Ir 6B is isotypic to Ti 2Rh 6B and its structure can be described as a defect double perovskite, A2BB' O6, where the A site is occupied by zirconium, the B site by boron, the O site by iridium but the B' site is vacant, leading to the formation of empty and boron-filled octahedral Ir 6 clusters. According to the result of tight-binding electronic structure calculations, Ir-B and Ir-Zr interactions are mainly responsible for the structural stability of the phase. According to COHP bonding analysis, the strongest bonding occurs for the Ir-B contacts, and the Ir-Ir bonding within the empty clusters is two times stronger than that in the BIr 6 octahedra.

The influence of alizarin and fluorescein on the photoactivity of Ni, Pt and Ru-doped TiO{sub 2} layers

Energy Technology Data Exchange (ETDEWEB)

Rosu, Marcela-Corina, E-mail: marcela.rosu@itim-cj.ro [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath Street, 400293, Cluj-Napoca (Romania); Suciu, Ramona-Crina; Lazar, Mihaela D.; Bratu, I. [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath Street, 400293, Cluj-Napoca (Romania)

2013-04-20

Highlights: ► The Ni, Pt, Ru-doped TiO{sub 2} materials and sensitized with alizarin and fluorescein dyes were prepared by wet chemical route. ► The samples were characterized by: UV–vis spectroscopy, spectrofluorimetry, FT/IR spectroscopy and microscopy, X-ray diffraction and N{sub 2} physisorption measurements. ► A combined influence of the dopants and dyes was observed, leading to a beneficial effect to TiO{sub 2} photoactivity. -- Abstract: The doping with different metal ions and sensitization with organic compounds are two well known methods used to improve the photoactivity of TiO{sub 2}. In this respect, the metallic ions-doped TiO{sub 2} samples were prepared by embedding Ni, Pt and Ru ions into TiO{sub 2} crystalline network and then, each sample was sensitized with alizarin and fluorescein dyes. The qualitative evaluation of prepared TiO{sub 2}-based materials was made by: UV–vis spectroscopy, spectrofluorimetry, FT/IR spectroscopy and microscopy, X-ray diffraction and N{sub 2} physisorption measurements. The optoelectronic properties investigated by UV–vis spectroscopy show that the optical response of Ni-doped TiO{sub 2} layer shifts to visible. The X-ray spectra do not show peaks of nickel, platinum and ruthenium oxide crystals or pure metals. The FT/IR spectra proved the presence of dye molecules adsorbed on titania nanoparticles surface. These results demonstrated that the studied dopants and dyes have potential to promote modified TiO{sub 2}-based materials as good candidates to be used in photolectrocatalytic processes.

Comparison of rheological, mechanical, electrical properties of HDPE filled with BaTiO{sub 3} with different polar surface tension

Energy Technology Data Exchange (ETDEWEB)

Su, Jun [Department of Polymer Science and Engineering, College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009 (China); College of Mechanics Engineering, Nanjing Institute of Industry Technology, Nanjing, 210023 (China); Zhang, Jun, E-mail: zhangjun@njtech.edu.cn [Department of Polymer Science and Engineering, College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009 (China)

2016-12-01

Graphical abstract: - Highlights: • The non-polar and short vinyl groups can greatly reduce G′ of HDPE composites. • Long chains on BaTiO{sub 3} surface enhance the interaction of BaTiO{sub 3} with HDPE. • Polar amino groups on BaTiO{sub 3} surface raise the interaction of BaTiO{sub 3} with HDPE. • Polar amino groups can boost the dielectric constant of HDPE composites. • The potential use in electronic equipment of the KH550 composites is obtained. - Abstract: In this work, three types of coupling agents: isopropyl trioleic titanate (NDZ105), vinyltriethoxysilane (SG-Si151), 3-aminopropyltriethoxysilane (KH550) were applied to modify the surface tension of Barium titanate (BaTiO{sub 3}) particles. The Fourier transform infrared (FT-IR) spectra confirm the chemical adherence of coupling agents to the particle surface. The long hydrocarbon chains in NDZ105 can cover the particle surface and reduce the polar surface tension of BaTiO{sub 3} from 37.53 mJ/m{sup 2} to 7.51 mJ/m{sup 2}, turning it from hydrophilic to oleophilic properties. The short and non-polar vinyl groups in SG-Si151 does not influence the surface tension of BaTiO{sub 3}, but make BaTiO{sub 3} have both hydrophilic and oleophilic properties. The polar amino in KH550 can keep BaTiO{sub 3} still with hydrophilic properties. It is found that SG-Si151 modified BaTiO{sub 3} has the lowest interaction with HDPE matrix, lowering the storage modulus of HDPE composites to the greatest extent. As for mechanical properties, the polar amino groups in KH550 on BaTiO{sub 3} surface can improve the adhesion of BaTiO{sub 3} with HDPE matrix, which increases the elongation at break of HDPE composites to the greatest extent. In terms of electrical properties, the polar amino groups on surface of BaTiO{sub 3} can boost the dielectric properties of HDPE/BaTiO{sub 3} composites and decrease the volume resistivity of HDPE/BaTiO{sub 3} composites. The aim of this study is to investigate how functional groups

Photocatalytic decouloration of malachite green dye by application of TiO2 nanotubes

International Nuclear Information System (INIS)

Prado, Alexandre G.S.; Costa, Leonardo L.

2009-01-01

The nanotubes of titania were synthesized in a hydrothermal system and characterized by scanning electronic microscopy (SEM), FT-IR, FT-Raman, and surface charge density by surface area analyzer. These nanomaterials were applied to photocatalyse malachite green dye degradation. Photodegradation capacity of TiO 2 nanotubes was compared to TiO 2 anatase photoactivity. Malachite dye was completely degraded in 75 and 105 min of reaction photocatalysed by TiO 2 nanotubes and TiO 2 anatase, respectively. Catalysts displayed high photodegradation activity at pH 4. TiO 2 nanotubes were easily recycled whereas the reuse of TiO 2 anatase was not effective. Nanotubes maintained 80% of their activity after 10 catalytic cycles and TiO 2 anatase presented only 8% of its activity after 10 cycles.

Short-term memory of TiO2-based electrochemical capacitors: empirical analysis with adoption of a sliding threshold

International Nuclear Information System (INIS)

Lim, Hyungkwang; Kim, Inho; Kim, Jin-Sang; Jeong, Doo Seok; Seong Hwang, Cheol

2013-01-01

Chemical synapses are important components of the large-scaled neural network in the hippocampus of the mammalian brain, and a change in their weight is thought to be in charge of learning and memory. Thus, the realization of artificial chemical synapses is of crucial importance in achieving artificial neural networks emulating the brain’s functionalities to some extent. This kind of research is often referred to as neuromorphic engineering. In this study, we report short-term memory behaviours of electrochemical capacitors (ECs) utilizing TiO 2 mixed ionic–electronic conductor and various reactive electrode materials e.g. Ti, Ni, and Cr. By experiments, it turned out that the potentiation behaviours did not represent unlimited growth of synaptic weight. Instead, the behaviours exhibited limited synaptic weight growth that can be understood by means of an empirical equation similar to the Bienenstock–Cooper–Munro rule, employing a sliding threshold. The observed potentiation behaviours were analysed using the empirical equation and the differences between the different ECs were parameterized. (paper)

Synthesis and characterization of FeTiO3 ceramics

Directory of Open Access Journals (Sweden)

Anil B. Gambhire

2016-09-01

Full Text Available Nanocrystalline FeTiO3 ceramic powders were prepared by the sol–gel process combined with a surfactant-assisted template method. The resulting powders were calcined at different temperatures ranging from 150 °C to 600 °C for 2 h in air. The results revealed that a pure hexagonal phase of FeTiO3 could be obtained at a low temperature, 600 °C. The phase evolution of FeTiO3 was investigated by X-ray diffraction patterns (XRD, Fourier-transform infrared spectroscopy (FT-IR, and X-ray photoelectron spectroscopy (XPS. Particle size and morphology were studied by transmission electron microscopy (TEM.

Summary of Test Results of MQXFS1—The First Short Model 150 mm Aperture Nb$_3$Sn Quadrupole for the High-Luminosity LHC Upgrade

CERN Document Server

Stoynev, S; Anerella, M; Bossert, R; Cavanna, E; Cheng, D; Dietderich, D; DiMarco, J; Felice, H; Ferracin, P; Chlachidze, G; Ghosh, A; Grosclaude, P; Guinchard, M; Hafalia, A R; Holik, E; Izquierdo Bermudez, S; Krave, S; Marchevsky, M; Nobrega, F; Orris, D; Pan, H; Perez, J C; Prestemon, S; Ravaioli, E; Sabbi, G; Salmi, T; Schmalzle, J; Strauss, T; Sylvester, C; Tartaglia, M; Todesco, E; Vallone, G; Velev, G; Wanderer, P; Wang, X; Yu, M

2017-01-01

The development of $Nb_3Sn$ quadrupole magnets for the High-Luminosity LHC upgrade is a joint venture between the US LHC Accelerator Research Program (LARP)* and CERN with the goal of fabricating large aperture quadrupoles for the LHC in-teraction regions (IR). The inner triplet (low-β) NbTi quadrupoles in the IR will be replaced by the stronger Nb$_{3}$Sn magnets boosting the LHC program of having 10-fold increase in integrated luminos-ity after the foreseen upgrades. Previously LARP conducted suc-cessful tests of short and long models with up to 120 mm aperture. The first short 150 mm aperture quadrupole model MQXFS1 was assembled with coils fabricated by both CERN and LARP. The magnet demonstrated strong performance at the Fermilab’s verti-cal magnet test facility reaching the LHC operating limits. This paper reports the latest results from MQXFS1 tests with changed pre-stress levels. The overall magnet performance, including quench training and memory, ramp rate and temperature depend-ence, is also sum...

Electrical resistivity of V-Cr-Ti alloys

Energy Technology Data Exchange (ETDEWEB)

Zinkle, S.J.; Gubbi, A.N.; Eatherly, W.S. [Oak Ridge National Lab., TN (United States)

1997-04-01

Room temperature electrical resistivity measurements have been performed on vanadium alloys containing 3-6%Cr and 3-6%Ti in order to evaluate the microstructural stability of these alloys. A nonlinear dependence on Cr and Ti concentration was observed, which suggests that either short range ordering or solute precipitation (perhaps in concert with interstitial solute clustering) has occurred in V-6Cr-6Ti.

Enhanced performance of dye-sensitized solar cells based on TiO{sub 2} with NIR-absorption and visible upconversion luminescence

Energy Technology Data Exchange (ETDEWEB)

Liang, Li [Department of Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Yulin, Yang, E-mail: ylyang@hit.edu.cn [Department of Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Mi, Zhou; Ruiqing, Fan; LeLe, Qiu [Department of Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Xin, Wang [Department of Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Department of Food and Environmental Engineering, Heilongjiang, East University, Harbin 150086 (China); Lingyun, Zhang [Department of Chemistry, Harbin Institute of Technology, Harbin 150001 (China); School of Chemical Engineering, Northeast Dianli University, Jilin 132012 (China); Xuesong, Zhou; Jianglong, He [Department of Chemistry, Harbin Institute of Technology, Harbin 150001 (China)

2013-02-15

TiO{sub 2} with NIR-absorption and visible upconversion luminescence (UC-TiO{sub 2}) is prepared by a sol-gel method and calcined at 700 Degree-Sign C for 6 h. The material broadens the response region of dye sensitized solar cells (DSSCs) from an ultraviolet-visible region to the whole region of the solar spectrum. It shifts NIR sunlight to visible light which matches the strong absorbing region of the dye (N719). DSSCs based on UC-TiO{sub 2} achieved higher conversion efficiency than that on raw TiO{sub 2}. UC-TiO{sub 2} was mixed with commercial raw TiO{sub 2} as additive, and the short-circuit current density, open-circuit voltage and conversion efficiency of the DSSC reached to the optimum values 13.38 mA/cm{sup 2}, 0.78 V and 6.63% (AM1.5 global), comparing with the blank values: 7.99 mA/cm{sup 2}, 0.75 V and 4.07%, respectively. Also the mechanisms of upconversion by multiphoton absorption and energy transfer processes are interpreted in this paper. - Graphical abstract: By introducing TiO{sub 2} with NIR-absorption and visible up-conversion luminescence into DSSC, a signal reflection was explored from ultra-violet region to visible region, and to near-IR region. Highlights: Black-Right-Pointing-Pointer TiO{sub 2} with NIR-absorption and visible up-conversion luminescence (UC-TiO{sub 2}) was prepared by a sol-gel method. Black-Right-Pointing-Pointer A systematic characterization and analysis was carried out to discuss the mechanism. Black-Right-Pointing-Pointer A significantly enhanced performance of DSSC was explored by using UC-TiO{sub 2} as an additive.

Preparation and electrochemical property of TiO_2/Nano-graphite composite anode for electro-catalytic degradation of ceftriaxone sodium

International Nuclear Information System (INIS)

Guo, Xiaolei; Li, Dong; Wan, Jiafeng; Yu, Xiujuan

2015-01-01

Titanium dioxide/Nano-graphite (TiO_2/Nano-G) composite was synthesized by a sol-gel method and TiO_2/Nano-G electrode was prepared in hot-press approach. The composite was characterized by X-ray photoelectron spectroscopy (XPS), fourier transform infrared (FT-IR), scanning electrons microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The electrochemical performance of the TiO_2/Nano-G anode electrode was investigated through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The electro-catalytic performance was evaluated by the yield of ·OH radicals, degradation of methyl orange and ceftriaxone sodium. The results demonstrated that TiO_2 nanoparticles were dispersed on the surface and interlamination of the Nano-G uniformly, TiO_2/Nano-G electrode owned higher electro-catalytic oxidation activity and stability than Nano-G electrode. Degradation rate of ceftriaxone sodium within 120 min by TiO_2(40)/Nano-G electrode was 97.7%. And ·OH radicals given by TiO_2/Nano-G electrode was higher than that of Nano-G electrode and DSA (Ti/IrO_2-RuO_2) electrode. The excellent electro-catalytic performance could be ascribed to the admirable conductive property of the Nano-G and more production of ·OH offered by TiO_2(40)/Nano-G electrode.

Impaired Insulin Signaling is Associated with Hepatic Mitochondrial Dysfunction in IR+/−-IRS-1+/− Double Heterozygous (IR-IRS1dh Mice

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Andras Franko

2017-05-01

Full Text Available Mitochondria play a pivotal role in energy metabolism, but whether insulin signaling per se could regulate mitochondrial function has not been identified yet. To investigate whether mitochondrial function is regulated by insulin signaling, we analyzed muscle and liver of insulin receptor (IR+/−-insulin receptor substrate-1 (IRS-1+/− double heterozygous (IR-IRS1dh mice, a well described model for insulin resistance. IR-IRS1dh mice were studied at the age of 6 and 12 months and glucose metabolism was determined by glucose and insulin tolerance tests. Mitochondrial enzyme activities, oxygen consumption, and membrane potential were assessed using spectrophotometric, respirometric, and proton motive force analysis, respectively. IR-IRS1dh mice showed elevated serum insulin levels. Hepatic mitochondrial oxygen consumption was reduced in IR-IRS1dh animals at 12 months of age. Furthermore, 6-month-old IR-IRS1dh mice demonstrated enhanced mitochondrial respiration in skeletal muscle, but a tendency of impaired glucose tolerance. On the other hand, 12-month-old IR-IRS1dh mice showed improved glucose tolerance, but normal muscle mitochondrial function. Our data revealed that deficiency in IR/IRS-1 resulted in normal or even elevated skeletal muscle, but impaired hepatic mitochondrial function, suggesting a direct cross-talk between insulin signaling and mitochondria in the liver.

Metal ion induced room temperature phase transformation and stimulated infrared spectroscopy on TiO2-based surfaces

International Nuclear Information System (INIS)

Gole, James L.; Prokes, S.M.; White, Mark G.

2008-01-01

Raman and infrared spectroscopy are used to demonstrate (1) the high spin metal ion induced room temperature transformation of anatase to rutile TiO 2 and (2) the phenomena of stimulated IR spectroscopy induced by simultaneous nitrogen doping and high spin metal ion seeding of a TiO 2 nanocolloid lattice

Incipient 2D Mott insulators in extreme high electron density, ultra-thin GdTiO3/SrTiO3/GdTiO3 quantum wells

Science.gov (United States)

Allen, S. James; Ouellette, Daniel G.; Moetakef, Pouya; Cain, Tyler; Chen, Ru; Balents, Leon; Stemmer, Susanne

2013-03-01

By reducing the number of SrO planes in a GdTiO3 /SrTiO3/ GdTiO3 quantum well heterostructure, an electron gas with ~ fixed 2D electron density can be driven close to the Mott metal insulator transition - a quantum critical point at ~1 electron per unit cell. A single interface between the Mott insulator GdTiO3 and band insulator SrTiO3 has been shown to introduce ~ 1/2 electron per interface unit cell. Two interfaces produce a quantum well with ~ 7 1014 cm-2 electrons: at the limit of a single SrO layer it may produce a 2D magnetic Mott insulator. We use temperature and frequency dependent (DC - 3eV) conductivity and temperature dependent magneto-transport to understand the relative importance of electron-electron interactions, electron-phonon interactions, and surface roughness scattering as the electron gas is compressed toward the quantum critical point. Terahertz time-domain and FTIR spectroscopies, measure the frequency dependent carrier mass and scattering rate, and the mid-IR polaron absorption as a function of quantum well thickness. At the extreme limit of a single SrO plane, we observe insulating behavior with an optical gap substantially less than that of the surrounding GdTiO3, suggesting a novel 2D Mott insulator. MURI program of the Army Research Office - Grant No. W911-NF-09-1-0398

Influence of surface modification on the apatite formation and corrosion behavior of Ti and Ti-15Mo alloy for biomedical applications

Energy Technology Data Exchange (ETDEWEB)

Sasikumar, Y. [Department of Chemistry, CEG Campus, Anna University, Chennai 600 025 (India); Rajendran, N., E-mail: nrajendran@annauniv.edu [Department of Chemistry, CEG Campus, Anna University, Chennai 600 025 (India)

2013-02-15

Commercially pure Ti and Ti-15Mo specimens were subjected to alkali-hydrogen peroxide and subsequent heat treatment to produce a nanoporous titanate gel layer with anatase phase. The surface morphology of the untreated, alkali-hydrogen peroxide treated and alkali-hydrogen peroxide heat treated specimens before and after 7 days of immersion in simulated body fluid was characterized using X-ray Diffractometer (XRD), Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FT-IR). The formation of nanoporous titanate gel layer and the growth of apatite layer over the surface modified specimens after 7 days of immersion in simulated body fluid were confirmed. Further, the electrochemical corrosion behavior of all the specimens was examined using potentiodynamic polarization and electrochemical impedance spectroscopic techniques. - Highlights: ► Simple thermochemical process for Cp-Ti and Ti-15Mo alloy. ► Formation of nanoporous titanate layer on surface facilitate apatite formation. ► Hydroxyapatite coated sample exhibited improved corrosion resistance.

Oxygen perovskites of type Ba/sub 3/Bsup(III)RuIrO/sub 9/

Energy Technology Data Exchange (ETDEWEB)

Duerrschmidt, E; Kemmler-Sack, S [Tuebingen Univ. (Germany, F.R.). Lehrstuhl fuer Anorganische Chemie 2

1980-11-01

The black perovskites Ba/sub 3/Bsup(III)RuIrO/sub 9/ with Bsup(III) = La, Nd, Sm, Gd, Dy, Er, Yb, In, Sc are isotypic. They crystallize in a hexagonal BaTiO/sub 3/ structure (sequence (hcc)/sub 2/). The mean oxydation state of the noble metal ions is +4.5.

Preparation and characterization of novel nanocomposite films formed from silk fibroin and nano-TiO2.

Science.gov (United States)

Feng, Xin-Xing; Zhang, Li-Li; Chen, Jian-Yong; Guo, Yu-Hai; Zhang, Hua-Peng; Jia, Chang-Ian

2007-01-30

This paper describes the synthesis and characterization of new regenerated silk fibroin (SF)/nano-TiO(2) composite films. The preparation method, based on the sol-gel technique using butyl titanate as oxide precursor, could avoid reagglomeration of the prepared nanoparticles. Samples were characterized mainly by X-ray diffraction (XRD), ultra-violet (UV) spectroscopy, atomic force microscopy (AFM), Fourier transform infrared (FT-IR) spectroscopy, and thermogravimetric analysis (TGA). The UV and AFM results indicated that TiO(2) nanoparticles could be well dispersed inside the SF film, and the size of TiO(2) was about 80nm. The XRD and FT-IR analysis implied that the formation of nano-TiO(2) particles may induce the conformational transition of silk fibroin to a typical Silk II structure partly with the increasing of crystallinity in the composite films. Compared to the pure SF films, the mechanical and thermal properties of composite films were improved, and the solubility in water was decreased due to the conformational transition of silk fibroin to Silk II structure.

Highly efficient removal of chlorotetracycline from aqueous solution using graphene oxide/TiO2 composite: Properties and mechanism

Science.gov (United States)

Li, Zhaoqian; Qi, Mengyu; Tu, Chunyan; Wang, Weiping; Chen, Jianrong; Wang, Ai-Jun

2017-12-01

The extensive usage of chlorotetracycline (CTC) has caused the persistence of antibiotic residues in aquatic environments, resulting in serious threat to human health and ecosystems. In this study, graphene oxide/titanium dioxide (GO/TiO2) nanocomposite was successfully synthesized via in situ hydrolysis of tetra-n-butyl titanate (Ti(BuO)4) to TiO2 particles on GO sheets and used as adsorbent for efficient adsorptive removal of CTC from aqueous solution. The prepared GO/TiO2 was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transformed infrared (FT-IR), Raman spectroscopy and X-ray photoelectron (XPS). Adsorption kinetics, isotherms and thermodynamics were systematically investigated to evaluate the adsorption properties of GO/TiO2. Adsorption mechanism was further analyzed by FT-IR, UV-vis and XPS. The results indicated that adsorption kinetics closely followed the pseudo-second order model; the maximum adsorption capacity determined by Langmuir model was 261.10 mg g-1 at 298 K and the thermodynamic studies revealed that the adsorption of CTC onto the GO/TiO2 was a spontaneous and endothermic process. Moreover, the interactions between CTC and GO/TiO2 were presumed to be ligand exchange between CTC and TiO2, while the π-π electron donor-acceptor interaction, hydrogen bond and cation-π bonding were constructed between CTC and GO. Finally, the prepared GO/TiO2 was successfully applied for the efficient removal of CTC from Wu River water.

The Short-Term Power Load Forecasting Based on Sperm Whale Algorithm and Wavelet Least Square Support Vector Machine with DWT-IR for Feature Selection

Directory of Open Access Journals (Sweden)

Jin-peng Liu

2017-07-01

Full Text Available Short-term power load forecasting is an important basis for the operation of integrated energy system, and the accuracy of load forecasting directly affects the economy of system operation. To improve the forecasting accuracy, this paper proposes a load forecasting system based on wavelet least square support vector machine and sperm whale algorithm. Firstly, the methods of discrete wavelet transform and inconsistency rate model (DWT-IR are used to select the optimal features, which aims to reduce the redundancy of input vectors. Secondly, the kernel function of least square support vector machine LSSVM is replaced by wavelet kernel function for improving the nonlinear mapping ability of LSSVM. Lastly, the parameters of W-LSSVM are optimized by sperm whale algorithm, and the short-term load forecasting method of W-LSSVM-SWA is established. Additionally, the example verification results show that the proposed model outperforms other alternative methods and has a strong effectiveness and feasibility in short-term power load forecasting.

Third-generation intelligent IR focal plane arrays

Science.gov (United States)

Caulfield, H. John; Jack, Michael D.; Pettijohn, Kevin L.; Schlesselmann, John D.; Norworth, Joe

1998-03-01

SBRC is at the forefront of industry in developing IR focal plane arrays including multi-spectral technology and '3rd generation' functions that mimic the human eye. 3rd generation devices conduct advanced processing on or near the FPA that serve to reduce bandwidth while performing needed functions such as automatic target recognition, uniformity correction and dynamic range enhancement. These devices represent a solution for processing the exorbitantly high bandwidth coming off large area FPAs without sacrificing systems sensitivity. SBRC's two-color approach leverages the company's HgCdTe technology to provide simultaneous multiband coverage, from short through long wave IR, with near theoretical performance. IR systems that are sensitive to different spectral bands achieve enhanced capabilities for target identification and advanced discrimination. This paper will provide a summary of the issues, the technology and the benefits of SBRC's third generation smart and two-color FPAs.

Fabrication and characterization of mesoporous TiO2/polypyrrole-based nanocomposite for electrorheological fluid

International Nuclear Information System (INIS)

Wei Chuan; Zhu Yihua; Jin Yi; Yang Xiaoling; Li Chunzhong

2008-01-01

Mesoporous TiO 2 /polypyrrole (PPy)-based nanocomposite for electrorheological fluid was synthesized through one-pot method. By exploiting the combination conductivity of PPy and high dielectric constant of TiO 2 , the ER fluid exhibited an enhanced effect. The shear stress was 3.3 times as high as that of mesoporous TiO 2 . Powder X-ray diffraction (XRD), TEM and Fourier transform infrared (FT-IR) spectroscopy were employed to characterize the as-made samples. Using a modified rotational viscometer, the electrorheological effect was measured. Dielectric spectra were also given to explain the mechanism

The synthesis of aqueous-dispersible anatase TiO2 nanoplatelets

International Nuclear Information System (INIS)

Shan Guobin; Demopoulos, George P

2010-01-01

Aqueous well-dispersed and phase-pure anatase TiO 2 truncated octahedron nanoplatelets (NPLs) were prepared via controlled hydrolysis of titanium tetrachloride (TiCl 4 ) in ethylene glycol at 240 deg. C. Two shapes, square and hexagon, were observed by microscopy, exactly corresponding to the truncated octahedron NPLs. Ethylene glycol was found to produce water in situ that reacts with TiCl 4 to produce TiO 2 and HCl-the latter promoting TiO 2 colloid peptization. TiO 2 truncated octahedron NPLs are formed under the stabilizing action of ethylene glycol thermolysis derivatives, such as aldehydes. Crystal growth of the TiO 2 NPLs was affected by the reaction temperature that determines the water production rate and HCl-assisted peptization. TGA and FT-IR results showed ∼1.2% ethylene glycol thermolysis derivatives are attached to the surface of the TiO 2 NPLs, which prevents their agglomeration, hence making them easily dispersible in aqueous media. HR-TEM and SAED results showed that the TiO 2 NPLs are well crystallized and that the SAED patterns of the single TiO 2 NPL changes with its size and shape. XRD patterns showed that the TiO 2 NPLs are phase-pure anatase and the percentage of the {101} plane in the TiO 2 NPLs to be only 18%-a structural feature that renders the TiO 2 NPLs with enhanced UV absorption and reactivity properties.

Removal Efficiency of Nitrite and Sulfide Pollutants by Electrochemical Process by Using Ti/RuIrO2 Anode

Directory of Open Access Journals (Sweden)

Aris Mukimin

2018-05-01

Full Text Available In general, wastewater treatment by physical, chemical and biological methods are only focused on TSS, BOD and COD removals that the effluent still contains anion pollutant as NO2- and S2-. Electrochemical technology is a proper method for those pollutants treatment due to its fast process, easy operation and minimum amount of sludge. Electrocatalytic reactor with 8 L capacity using Ti/RuIrO2 cylinder as anode and Fe plate as cathode was arranged and applied to treat anion pollutants. Hydraulic retention time (30, 60, 90 and 120 min, salt concentration (250, 500 and 750 mg/L and voltage (4, 5, and 6 V were chosen as operation variables and NO2- and S2- concentrations as parameter indicators. Nitrite removal efficiency reached 75 and 99.7% after 60 and 120 min of electrolysis, respectively, while sulfide could obtain higher efficiency, i.e., 97 and 99.9% after 60 and 90 min, respectively, at operation variables of potential of 5 V and salt of 500 mg/L. Removal process is dominated by indirect oxidation mechanism by HClO/ClO- oxidators generated at anode surface as intermediate products. The lifespan of electrode and electric consumption are two main factors of operation cost. Electric consumed was 0.452 kWh per 1 g nitrite removed.

Eco-friendly synthesis of TiO2, Au and Pt doped TiO2 nanoparticles for dye sensitized solar cell applications and evaluation of toxicity

Science.gov (United States)

Gopinath, K.; Kumaraguru, S.; Bhakyaraj, K.; Thirumal, S.; Arumugam, A.

2016-04-01

Driven by the demand of pure TiO2, Au and Pt doped TiO2 NPs were successfully synthesized using Terminalia arjuna bark extract. The eco-friendly synthesized NPs were characterized by UV-Vis-DRS, ATR-FT-IR, PL, XRD, Raman, SEM with EDX and TEM analysis. The synthesized NPs were investigation for dye sensitized solar cell applications. UV-Vis-Diffused Reflectance Spectra clearly showed that the expected TiO2 inter band absorption below 306 nm, incorporation of gold shows surface plasma resonant (SPR) near 555 nm and platinum incorporated TiO2 NPs shows absorbance at 460 nm. The energy conversion efficiency for Au doped TiO2 NPs when compared to pure and Pt doped TiO2 NPs. In addition to that, Au noble metal present TiO2 matrix and an improve open-circuit voltage (Voc) of DSSC. Synthesized NPs was evaluated into antibacterial and antifungal activities by disk diffusion method. It is observed that NPs have not shown any activities in all tested bacterial and fungal strains. In this eco-friendly synthesis method to provide non toxic and environmental friendly nanomaterials can be used for solar energy device application.

TiO2/Halloysite Composites Codoped with Carbon and Nitrogen from Melamine and Their Enhanced Solar-Light-Driven Photocatalytic Performance

Directory of Open Access Journals (Sweden)

Pengcheng Yao

2015-01-01

Full Text Available Carbon (C and nitrogen (N codoped anatase TiO2/amorphous halloysite nanotubes (C+N-TiO2/HNTs were fabricated using melamine as C and N source. The samples prepared by different weight ratios of melamine and TiO2 were investigated by X-ray diffraction (XRD and UV-vis diffuse reflectance spectrometer. It is shown that the doping amounts of C and N could influence the photocatalytic performance of as-prepared composites. When the weight ratio of melamine/TiO2 is 4.5, the C+N-TiO2/HNTs exhibited the best photocatalytic degradation efficiency of methyl blue (MB under solar light irradiation. The obtained C+N-TiO2/HNTs were characterized by transmission electron microscopy (TEM, N2 adsorption-desorption isotherm (BET, X-ray photoelectron spectroscopy (XPS, and Fourier transform infrared spectrum (FT-IR. The results showed that the aggregation was effectively reduced, and TiO2 nanoparticles could be uniformly deposited on the surface of HNTs. This leads to an increase of their specific surface area. XPS and FT-IR analyses indicated TiO2 particles were doped successfully with C and N via the linkage of the Ti–O–N, O–Ti–N, and Ti–O–C. Photocatalytic experiments showed that C+N-TiO2/HNTs had higher degradation efficiency of MB than TiO2/HNTs. This makes the composite a potential candidate for the photocatalytic wastewater treatment.

Photocatalytic activity of Fe-doped CaTiO₃ under UV-visible light.

Science.gov (United States)

Yang, He; Han, Chong; Xue, Xiangxin

2014-07-01

The photocatalytic degradation of methylene blue (MB) over Fe-doped CaTiO₃ under UV-visible light was investigated. The as-prepared samples were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM) equipped with an energy dispersive spectrometer (EDS) system, Fourier transform infrared spectra (FT-IR), and UV-visible diffuse reflectance spectroscopy (DRS). The results show that the doping with Fe significantly promoted the light absorption ability of CaTiO₃ in the visible light region. The Fe-doped CaTiO₃ exhibited higher photocatalytic activity than CaTiO₃ for the degradation of MB. However, the photocatalytic activity of the Fe-doped CaTiO₃ was greatly influenced by the calcination temperature during the preparation process. The Fe-doped CaTiO₃ prepared at 500°C exhibited the best photocatalytic activity, with degradation of almost 100% MB (10ppm) under UV-visible light for 180 min. Copyright © 2014. Published by Elsevier B.V.

High-performance broadband photodetector using solution-processible PbSe-TiO(2)-graphene hybrids.

Science.gov (United States)

Manga, Kiran Kumar; Wang, Junzhong; Lin, Ming; Zhang, Jie; Nesladek, Milos; Nalla, Venkatram; Ji, Wei; Loh, Kian Ping

2012-04-03

Highly sensitive, multicomponent broadband photodetector devices are made from PbSe/graphene/TiO(2). TiO(2) and PbSe nanoparticles act as light harvesting photoactive materials from the UV to IR regions of the electromagnetic spectrum, while the graphene acts as a charge collector for both photogenerated holes and electrons under an applied electric field. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Metal ion induced room temperature phase transformation and stimulated infrared spectroscopy on TiO{sub 2}-based surfaces

Energy Technology Data Exchange (ETDEWEB)

Gole, James L. [Schools of Physics and Mechanical Engineering, Georgia Institute of Technology, 837 State Street, Atlanta, GA 30332-0430 (United States)], E-mail: jim.gole@physics.gatech.edu; Prokes, S.M. [Code 6876, NRL, Washington, DC 20375 (United States)], E-mail: prokes@estd.nrl.navy.mil; White, Mark G. [Dave C. Swalm School of Chemical Engineering, James Worth Bagley College of Engineering, Box 959, MS 39762 (United States)], E-mail: white@che.msstate.edu

2008-11-30

Raman and infrared spectroscopy are used to demonstrate (1) the high spin metal ion induced room temperature transformation of anatase to rutile TiO{sub 2} and (2) the phenomena of stimulated IR spectroscopy induced by simultaneous nitrogen doping and high spin metal ion seeding of a TiO{sub 2} nanocolloid lattice.

Completely automated open-path FT-IR spectrometry.

Science.gov (United States)

Griffiths, Peter R; Shao, Limin; Leytem, April B

2009-01-01

Atmospheric analysis by open-path Fourier-transform infrared (OP/FT-IR) spectrometry has been possible for over two decades but has not been widely used because of the limitations of the software of commercial instruments. In this paper, we describe the current state-of-the-art of the hardware and software that constitutes a contemporary OP/FT-IR spectrometer. We then describe advances that have been made in our laboratory that have enabled many of the limitations of this type of instrument to be overcome. These include not having to acquire a single-beam background spectrum that compensates for absorption features in the spectra of atmospheric water vapor and carbon dioxide. Instead, an easily measured "short path-length" background spectrum is used for calculation of each absorbance spectrum that is measured over a long path-length. To accomplish this goal, the algorithm used to calculate the concentrations of trace atmospheric molecules was changed from classical least-squares regression (CLS) to partial least-squares regression (PLS). For calibration, OP/FT-IR spectra are measured in pristine air over a wide variety of path-lengths, temperatures, and humidities, ratioed against a short-path background, and converted to absorbance; the reference spectrum of each analyte is then multiplied by randomly selected coefficients and added to these background spectra. Automatic baseline correction for small molecules with resolved rotational fine structure, such as ammonia and methane, is effected using wavelet transforms. A novel method of correcting for the effect of the nonlinear response of mercury cadmium telluride detectors is also incorporated. Finally, target factor analysis may be used to detect the onset of a given pollutant when its concentration exceeds a certain threshold. In this way, the concentration of atmospheric species has been obtained from OP/FT-IR spectra measured at intervals of 1 min over a period of many hours with no operator intervention.

Short-length and high-density TiO2 nanorod arrays for the efficient charge separation interface in perovskite solar cells

International Nuclear Information System (INIS)

Xiao, Guannan; Shi, Chengwu; Zhang, Zhengguo; Li, Nannan; Li, Long

2017-01-01

O 2 nanorod arrays. • Preparation of over-500 nm-thickness CH 3 NH 3 PbI 3−x Br x absorber layer. • Combination of short-length TiO 2 nanorod array and high-thickness perovskite layer. • The best and average PCE with TiO 2 array of 15.93% and 13.41±2.52% at 50–54% RH.

Design of an efficient photoanode for dye-sensitized solar cells using electrospun one-dimensional GO/N-doped nanocomposite SnO{sub 2}/TiO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Mohamed, Ibrahim M.A. [Department of Bionanosystem Engineering, Graduate School, Chonbuk National University, Jeonju, 561-756 (Korea, Republic of); Department of Chemistry, Faculty of Science, Sohag University, Sohag 82524 (Egypt); Dao, Van-Duong [Department of Chemical Engineering & Applied Chemistry, Chungnam National University, 220 Gung-Dong, Yuseong-Gu, Daejeon, 305-764 (Korea, Republic of); Yasin, Ahmed S. [Department of Bionanosystem Engineering, Graduate School, Chonbuk National University, Jeonju, 561-756 (Korea, Republic of); Barakat, Nasser A.M., E-mail: nasser@jbnu.ac.kr [Department of Bionanosystem Engineering, Graduate School, Chonbuk National University, Jeonju, 561-756 (Korea, Republic of); Department of Chemical Engineering, Faculty of Engineering, Minia University, El-Minia (Egypt); Choi, Ho-Suk [Department of Chemical Engineering & Applied Chemistry, Chungnam National University, 220 Gung-Dong, Yuseong-Gu, Daejeon, 305-764 (Korea, Republic of)

2017-04-01

Highlights: • GO &N@SnO{sub 2}/TiO{sub 2} NFs are synthesized via facile two steps. • The novel NFs photoanode exhibit high dye-loading ability; 2.164 × 10{sup −7} mol/cm{sup 2}. • Prolonged electron lifetime (20.09 ms) is due to reduced charge recombination. • High power conversion efficiency was achieved; 6.18%. - Abstract: This study presents the combination of N, graphene oxide (GO) and SnO{sub 2} as efficient dopants into TiO{sub 2} nanofibers (NFs) photoanode substrate for highly efficient dye-sensitized solar cells (DSCs). The developed NFs are synthesized by electrospinning and hydrothermal processes and characterized by FESEM, TEM, XPS, FT-IR, Raman and EDX-studies. The formation of short NFs is confirmed through FESEM and TEM measurements. As the results, the major crystal structure of TiO{sub 2} in the prepared NFs has anatase (85.23%) and rutile-structure (14.67%). XPS and EDX studies affirm that the material has Ti, O, Sn, N and C elements. In addition, FT-IR and Raman spectra give an indication about the GO-content. Typically, the DSC based on the novel NFs shows 6.18% efficiency. The J{sub sc}, V{sub oc}, FF and R{sub ct} are estimated and found to be 10.32 mA cm{sup −2}, 0.825 V, 0.73 and 21.66 Ω, respectively. The high-power efficiency is contributed by three reasons. The first one is the high dye-loading (2.16 × 10{sup −7} mol cm{sup −2}). The second reason is the enhanced charge transfer and decreasing of the electrons/holes recombination through formation of wide band-gap oxide (3.246 eV). Finally, the third one is GO-doping which may create new routes for the electron transfer in working electrode layer.

Double functions of porous TiO2 electrodes on CH3NH3PbI3 perovskite solar cells: Enhancement of perovskite crystal transformation and prohibition of short circuiting

Directory of Open Access Journals (Sweden)

Govindhasamy Murugadoss

2014-08-01

Full Text Available In order to analyze the crystal transformation from hexagonal PbI2 to CH3NH3PbI3 by the sequential (two-step deposition process, perovskite CH3NH3PbI3 layers were deposited on flat and/or porous TiO2 layers. Although the narrower pores using small nanoparticles prohibited the effective transformation, the porous-TiO2 matrix was able to help the crystal transformation of PbI2 to CH3NH3PbI3 by sequential two-step deposition. The resulting PbI2 crystals in porous TiO2 electrodes did not deteriorate the photovoltaic effects. Moreover, it is confirmed that the porous TiO2 electrode had served the function of prohibiting short circuits between working and counter electrodes in perovskite solar cells.

Performance of the first short model 150 mm aperture Nb$_3$Sn Quadrupole MQXFS for the High-Luminosity LHC upgrade

CERN Document Server

Chlachidze, G; Anerella, M; Bossert, R; Cavanna, E; Cheng, D; Dietderich, D; DiMarco, J; Felice, H; Ferracin, P; Ghosh, A; Grosclaude, P; Guinchard, M; Hafalia, A R; Holik, E; Izquierdo Bermudez, S; Krave, S; Marchevsky, M; Nobrega, F; Orris, D; Pan, H; Perez, J C; Prestemon, S; Ravaioli, E; Sabbi, G L; Salmi, T; Schmalzle, J; Stoynev, S; Strauss, T; Sylvester, C; Tartaglia, M; Todesco, E; Vallone, G; Velev, G; Wanderer, P; Wang, X; Yu, M

2017-01-01

The US LHC Accelerator Research Program (LARP) and CERN combined their efforts in developing Nb$_{3}$Sn magnets for the High-Luminosity LHC upgrade. The ultimate goal of this collaboration is to fabricate large aperture Nb$_{3}$Sn quadrupoles for the LHC interaction regions (IR). These magnets will replace the present 70 mm aperture NbTi quadrupole triplets for expected increase of the LHC peak luminosity by a factor of 5. Over the past decade LARP successfully fabricated and tested short and long models of 90 mm and 120 mm aperture Nb$_{3}$Sn quadrupoles. Recently the first short model of 150 mm diameter quadrupole MQXFS was built with coils fabricated both by the LARP and CERN. The magnet performance was tested at Fermilab’s vertical magnet test facility. This paper reports the test results, including the quench training at 1.9 K, ramp rate and temperature dependence studies.

Performance of the first short model 150 mm aperture Nb$_3$Sn Quadrupole MQXFS for the High- Luminosity LHC upgrade

Energy Technology Data Exchange (ETDEWEB)

Chlachidze, G.; et al.

2016-08-30

The US LHC Accelerator Research Program (LARP) and CERN combined their efforts in developing Nb3Sn magnets for the High-Luminosity LHC upgrade. The ultimate goal of this collaboration is to fabricate large aperture Nb3Sn quadrupoles for the LHC interaction regions (IR). These magnets will replace the present 70 mm aperture NbTi quadrupole triplets for expected increase of the LHC peak luminosity by a factor of 5. Over the past decade LARP successfully fabricated and tested short and long models of 90 mm and 120 mm aperture Nb3Sn quadrupoles. Recently the first short model of 150 mm diameter quadrupole MQXFS was built with coils fabricated both by the LARP and CERN. The magnet performance was tested at Fermilab’s vertical magnet test facility. This paper reports the test results, including the quench training at 1.9 K, ramp rate and temperature dependence studies.

Effect of tertiary amines on the synthesis and photovoltaic properties of TiO2 nanoparticles in dye sensitized solar cells

International Nuclear Information System (INIS)

Mir, Noshin; Salavati-Niasari, Masoud

2013-01-01

Highlights: • TiO 2 nanoparticles were synthesized via a two-step sol–gel method. • Two tertiary amines were selected as complexing agents. • Size control was achieved by selection of long chained amine. • The total conversion efficiency of 5.04% was reported as the best result. -- Abstract: Two different amines as complexing agents were used in a two-step sol–gel method to prepare TiO 2 nanoparticles. The effect of amines on the size of the TiO 2 nanocrystals and its influence on the performance of corresponding dye-sensitized solar cell (DSSC) were investigated. It is shown that using a tertiary long chained monoamine as a complexing agent is beneficial in two ways; one is producing the particles with smaller size and the other is slightly sticking the particles in order to have a film with higher reflectivity which both is beneficial to photovoltaic performance. The obtained products were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectra, and ultraviolet-visible (UV–vis) spectroscopy. The overall conversion efficiency of the long-chain-based DSSC (5.04%) appeared to be 45% higher than that obtained for the tertiary short-chain diamine

Alkoholio ir tabako pasiūlos ir paklausos teisinio reguliavimo raida Lietuvos Respublikoje: problemos ir sprendimai

OpenAIRE

Mockevičius, Arminas

2014-01-01

Viešosios teisės magistro studijų programos studento Armino Mockevičiaus buvo parašytas magistro baigiamasis darbas „Alkoholio ir tabako pasiūlos ir paklausos teisinio reguliavimo raida Lietuvos Respublikoje: problemos ir sprendimai“. Šis darbas parašytas Vilniuje, 2014 metais, Mykolo Romerio universiteto Teisės fakulteto Konstitucinės ir administracinės teisės institute, vadovaujant dr. Gintautui Vilkeliui, apimtis 98 p. Darbo tikslas yra atskleisti alkoholio ir tabako pasiūlos ir paklau...

Tight-binding calculation of Ti-Rh--type phase diagram

International Nuclear Information System (INIS)

Sluiter, M.; Turchi, P.; Fu Zezhong; de Fontaine, D.

1988-01-01

Tight-binding electronic band-structure calculations were combined with a free-energy expression from a statistical mechanical method called the cluster-variation method. The effective pair interactions used in the cluster-variation calculation were evaluated by the generalized perturbation method. Only d orbitals were included and the numbers of d electrons per atom were taken to be three for the pure A element and eight for the pure B. A phase diagram was constructed incorporating, for the first time, both fcc and bcc lattices and their simple-ordered superstructures. The calculated diagram agreed reasonably well with those determined empirically for Ti-Rh or Ti-Ir

Detector de IR de lámina ferroeléctrica de (Pb,CaTiO3

Directory of Open Access Journals (Sweden)

González, A.

2002-02-01

Full Text Available A sol-gel (Pb0.76Ca0.24TiO3 solution was deposited onto Pt/MgO(100 substrates. Previous thermal treatment of the substrate and the high rate of crystallization heating promote an important preferred orientation along the polar axis, and therefore selfpolarization , very convenient for the use of IR pyroelectric detectors. By depositing circular electrodes, 7.10-3 cm2 of area, an array of small capacitors are developed which are characterized as detectors in standard conditions: radiation from a black-body at 500 K, modulated between 1-20 Hz, a lock-in amplifier and an electronic circuit to sense and treat the electrical response. Three main factors affecting the detector performances are analyzed: a Figures of merit of the pyroelectric material; b assembly of the whole parts of detector (substrate, electrodes, leads, frame, etc and c electronic circuitry to sense and amplify signals. Thermal isolation is concluding as the most important fact to improve responsivity.Se han obtenido depósitos multicapa de titanato de plomo modificado con calcio, (Pb0.76Ca0.24TiO3, mediante un método de sol-gel, sobre substratos de Pt/MgO(100. El tratamiento térmico del substrato y la cristalización de las multicapas mediante tasas de calentamiento rápidas causan el desarrollo de una importante orientación preferente según el eje polar, perpendicular al mismo, lo que supone una autopolarización muy rentable para su empleo en detectores piroeléctricos de radiación infrarroja. Mediante una configuración de electrodos discretos se fabrican minicondensadores de 7.10-3 cm2 de área con los que se caracteriza ópticamente el detector para condiciones estándar: cuerpo negro a 500 K, modulación mecánica de la radiación entre 1-20 Hz, una electrónica de acondicionamiento de la señal de respuesta y un amplificador sintonizado para medir la respuesta en voltaje. Se analiza el efecto de los tres factores que intervienen en la fabricación del detector: a

The design and application of a multi-band IR imager

Science.gov (United States)

Li, Lijuan

2018-02-01

Multi-band IR imaging system has many applications in security, national defense, petroleum and gas industry, etc. So the relevant technologies are getting more and more attention in rent years. As we know, when used in missile warning and missile seeker systems, multi-band IR imaging technology has the advantage of high target recognition capability and low false alarm rate if suitable spectral bands are selected. Compared with traditional single band IR imager, multi-band IR imager can make use of spectral features in addition to space and time domain features to discriminate target from background clutters and decoys. So, one of the key work is to select the right spectral bands in which the feature difference between target and false target is evident and is well utilized. Multi-band IR imager is a useful instrument to collect multi-band IR images of target, backgrounds and decoys for spectral band selection study at low cost and with adjustable parameters and property compared with commercial imaging spectrometer. In this paper, a multi-band IR imaging system is developed which is suitable to collect 4 spectral band images of various scenes at every turn and can be expanded to other short-wave and mid-wave IR spectral bands combination by changing filter groups. The multi-band IR imaging system consists of a broad band optical system, a cryogenic InSb large array detector, a spinning filter wheel and electronic processing system. The multi-band IR imaging system's performance is tested in real data collection experiments.

Synthesis, Characterization, and Photocatalytic Activity of TiO2 Microspheres Functionalized with Porphyrin

Directory of Open Access Journals (Sweden)

Jin-Hua Cai

2012-01-01

Full Text Available In order to utilize visible light more efficiently in the photocatalytic reaction, TiO2 microspheres sensitized by 5-(4-allyloxyphenyl-10,15,20-tri(4-methylphenylporphyrin (APTMPP were prepared and characterized by X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, nitrogen physisorption, scanning electron microscopy (SEM, Fourier transform infrared spectroscopy (FT-IR and UV-vis diffuse reflectance spectroscopy, and so forth, The characterization results indicated that APTMPP-MPS-TiO2 was composed of the anatase crystal phase. The morphology of the composite materials was spheriform with size of 0.3–0.7 μm and the porphyrin was chemisorbed on the surface of TiO2 through a Si–O–Ti bond. The photooxidation of α-terpinene was employed as the model reaction to evaluate the photocatalytic activity of APTMPP-MPS-TiO2 microspheres under visible light. The results indicated that the photodegradation of α-terpinene was significantly enhanced in the presence of the APTMPP-MPS-TiO2 compared with the nonmodified TiO2 under visible light.

Electronic structure of layered ferroelectric high-k titanate Pr2Ti2O7

Science.gov (United States)

Atuchin, V. V.; Gavrilova, T. A.; Grivel, J.-C.; Kesler, V. G.; Troitskaia, I. B.

2012-11-01

The spectroscopic parameters and electronic structure of binary titanate Pr2Ti2O7 have been studied by IR-, Raman and X-ray photoelectron spectroscopy (XPS) for the powder sample prepared by solid state synthesis. The spectral features of valence band and all constituent element core levels have been considered. The Auger parameters of titanium and oxygen in Pr2Ti2O7 have been determined as αTi=872.8 and αO=1042.3 eV. Variations of cation-anion bond ionicity have been discussed using binding energy differences ΔTi=(BE O 1s-BE Ti 2p3/2)=71.6 eV and ΔPr=BE(Pr 3d5/2)-BE(O 1s)=403.8 eV as key parameters in comparison with those of other titanium- and praseodymium-bearing oxides.

Effect of TiO2 photocatalytic activity in a HDPE-based food packaging on the structural and microbiological stability of a short-ripened cheese.

Science.gov (United States)

Gumiero, Matteo; Peressini, Donatella; Pizzariello, Andrea; Sensidoni, Alessandro; Iacumin, Lucilla; Comi, Giuseppe; Toniolo, Rosanna

2013-06-01

A high density polyethylene (HDPE)/calcium carbonate (CaCO(3)) film containing TiO(2) was prepared via blown film extrusion process. The photocatalytic properties of this film were evaluated by voltammetric, UV-Vis spectrophotometric and gas chromatographic measurements following the decomposition rate of suitably selected molecular probes, such as 4-hydroxybenzoic acid and methylene blue. The film containing 1% w/w of TiO(2) displayed a profitable and reproducible photoinduced degradation activity towards target organic compounds. The effect of packaging photocatalytic activity on the structural and microbiological stability of a short-ripened cheese was studied. Cheese structure was assessed by dynamic, small deformation rheological tests. A container consisting of a multilayer material, where the layer brought in contact with the food, made from the HDPE+CaCO(3)+TiO(2) composite matrix, was able to provide a greater maintenance of the original cheese structure than a rigid container currently used, mainly due to the inhibition of lactic acid bacteria and coliforms. Copyright © 2012 Elsevier Ltd. All rights reserved.

A Note on TI-Subgroups of Finite Groups

Indian Academy of Sciences (India)

A subgroup of a finite group is called a TI-subgroup if H ∩ H x = 1 or for any x ∈ G . In this short note, the finite groups all of whose nonabelian subgroups are TI-subgroups are classified. Author Affiliations. Jiakuan Lu1 Linna Pang1. Department of Mathematics, Guangxi Normal University, Guangxi, Guilin 541004, ...

Photocatalytic activity of TiO2/Nb2O5/PANI and TiO2/Nb2O5/RGO as new nanocomposites for degradation of organic pollutants.

Science.gov (United States)

Zarrin, Saviz; Heshmatpour, Felora

2018-06-05

In this study, highly active titanium dioxide modified by niobium oxide (Nb 2 O 5 ), polymer (PANI) and reduced graphene oxide (RGO) were successfully prepared. The morphology, structure, surface area and light absorption properties of the present nanocomposites for removal of methylene blue (MB) and methyl orange (MO) were investigated and compared with those of TiO 2 /Nb 2 O 5 and TiO 2 nanoparticles. The characterization techniques such as XRD, FT-IR, UV-vis, SEM, EDX, BET and TEM were employed in order to identify the nanocomposites. Also, photocatalytic properties of TiO 2 /Nb 2 O 5 /PANI and TiO 2 /Nb 2 O 5 /RGO nanocomposites under visible light irradiation were studied. In this way, the obtained results were compared to each other and also compared to TiO 2 /Nb 2 O 5 and TiO 2 nanoparticles. In this context, the chemical oxygen demand (COD) removal follows the photodegradation in observed performance. The results indicate that reduced TiO 2 /Nb 2 O 5 nanocomposite is effectively modified by graphene oxide to give TiO 2 /Nb 2 O 5 /RGO composite. The TiO 2 /Nb 2 O 5 /RGO exhibits significantly higher photocatalytic activity in degradation of organic dyes under visible light rather than that of TiO 2 /Nb 2 O 5 /PANI, TiO 2 /Nb 2 O 5 and pure TiO 2 . Copyright © 2018 Elsevier B.V. All rights reserved.

Micro-Arc oxidation of Ti in a solution of sulfuric acid and Ti+3 salt

International Nuclear Information System (INIS)

Ragalevicius, Rimas; Stalnionis, Giedrius; Niaura, Gediminas; Jagminas, Arunas

2008-01-01

A comparative study was performed on the behavior of titanium electrode in a sulfuric acid solution with and without Ti +3 during micro-arc oxidation under the constant current density control regime. The composition and microstructure of the obtained micro-arc films were analyzed using scanning electron microscopy, glancing-angle X-ray diffractometry, Raman and energy-dispersive X-ray spectroscopies. We have shown that addition of a Ti +3 salt extends the region of current densities (j a ) can be used for micro-arc oxidation of Ti and results in an obvious change of sparking behavior from extensive, large and long-played sparks to numerous, small and short sparks. As a consequence, the titania films formed in the Ti +3 -containing solutions are relatively thick, more uniform, composed of almost pure crystalline anatase and rutile phases of TiO 2 , and contain a network of evenly distributed small pores. It has also been shown that these films are promising for applications in catalysis, sensors and optoelectronics. The Raman spectra indicate that an increase in the electrolysis time of titanium in the Ti +3 -containing solution leads to the increase in rutile content, as expected

Management Report: Improvements Needed in IRS's Accounting Procedures and Internal Controls

National Research Council Canada - National Science Library

2002-01-01

... with requirements of the Federal Financial Management Improvement Act of 1996. A separate report on the implementation status of recommendations from our prior IRS financial audits and related financial management reports will be issued shortly...

Characterization and mechanism analysis of N doped TiO2 with visible light response and its enhanced visible activity

International Nuclear Information System (INIS)

Cheng Xiuwen; Yu Xiujuan; Xing Zipeng

2012-01-01

Nitrogen doped TiO 2 nanoparticles were synthesized through a hydrolysis-precipitation process using ammonia water as the doping species. The resulting materials were characterized by XRD, DRS, SPS, XPS and FT-IR. Further, the activity enhanced-mechanism was discussed in detail. XRD results showed that doping with nitrogen could effectively retard the phase transformation of TiO 2 from anatase to rutile and increase the anatase crystallinity. DRS and SPS results indicated that the light absorbance edge of nitrogen doped TiO 2 nanoparticle was obviously red-shifted to visible light region and the separation rates of photogenerated charge carriers were greatly improved, respectively. XPS and FT-IR analysis implied that the contents of surface hydroxyl groups were improved significantly and the VBM (valance bond maximum) of O2p was 2.3 eV. Under the visible light irradiation with 120 min, a 65.3% degradation rate of phenol could be achieved. The photocatalytic activity of nitrogen doped TiO 2 was 2.08 and 1.97 times than that of pure TiO 2 and P25 TiO 2 , respectively. The enhanced visible light activity was attributed to the well anatase crystallinity, small crystallite size, intense light absorbance edge in visible region, more content of surface hydroxyl groups and high separation efficiency of photogenerated charge carriers.

Humora stilu un apmierinātības ar darbu dzimumatšķirības

OpenAIRE

Ozoliņa, Diāna

2017-01-01

Pētījuma mērķis bija izpētīt, vai un kā ar apmierinātību ar darbu saistīti dažādi humora stili, vērtējot sakarības un atšķirības sieviešu un vīriešu izlasē. Pētījumā piedalījās 122 respondenti vecumā no 16-60 gadiem, no kuriem 65% dalībnieku ir sievietes, 35% ir vīrieši. Respondenti elektroniskā veidā aizpildīja Demogrāfisko datu aptauju, Humora stilu aptauju (Humor Style Questionnaire, R. Martin, et al, 2003, adaptācija latviešu valodā I. Stokenberga, 2004), kas mēra četrus humora stilus (b...

The chemical bonds effect of anthocyanin and chlorophyll dyes on TiO2 for dye-sensitized solar cell (DSSC)

Science.gov (United States)

Ahliha, A. H.; Nurosyid, F.; Supriyanto, A.; Kusumaningsih, T.

2017-11-01

Anthocyanin and chlorophyll dyes have been blended as the photosensitizer of Dye-Sensitized Solar Cell (DSSC). The results study showed the effect of chemical bond dyes on TiO2 and the efficiency of DSSC. Ratio blend of the anthocyanin and chlorophyll dyes are 1:1. The absorbance of dyes and TiO2 were characterized using UV-Vis Spectrophotometer. The chemical bonds contained in TiO2-dyes were characterized using FT-IR spectrophotometer. The efficiency of DSSC was calculated using I-V meter. The absorption spectra of chlorophyll: anthocyanin blend dye solutions and TiO2 films can increase after the dye adsorption. Absorbance characterization of anthocyanin and chlorophyll dye blend solutions showed three peaks at the wavelength of 412 nm; 535.5 nm; and 656.5 nm. Absorbance characterization of spinach before being blend with anthocyanin dyes solutions showed two peaks at the wavelength of 431 nm and 665.5 nm. The absorption spectra of TiO2 films can increase after the dyes adsorption at the wavelength of 400 nm. FT-IR spectra of TiO2 founded the functional groups C-Br, C=C, and O-H. The functional groups founded in anthocyanin: chlorophyll dye blended on the surface of TiO2 are C-Br, C-O, O-H, C-H, C=C, C=O, and O-H. The result showed that the greatest efficiency of 0.0544% at dye red cabbage-spinach. Adsorption blends of anthocyanin and chlorophyll dyes on the surface of TiO2 can be used as the photosensitizer for DSSC.

Self-assembled supramolecular system PDINH on TiO2 surface enhances hydrogen production.

Science.gov (United States)

Li, Xin; Lv, Xingshuai; Zhang, Qianqian; Huang, Baibiao; Wang, Peng; Qin, Xiaoyan; Zhang, Xiaoyang; Dai, Ying

2018-09-01

Constructing organic-inorganic hybrids is one of the hopeful strategies to improve photocatalyst performance. In this study, perylene-3,4,9,10-tetracarboxylic diimide (PDINH) and commercial TiO 2 P25 are chosen as raw materials to construct a PDINH/TiO 2 organic-inorganic hybrid, which has higher photocatalytic H 2 production activity and photocurrent intensity than pure PDINH and TiO 2 , respectively. The apparent quantum efficiency for H 2 production over 0.5%PDINH/TiO 2 reaches as high as 70.69% using irradiation at 365 nm. Moreover, XRD, DRS, HRTEM, FT-IR, and XPS are used to characterize the crystal structure, optical absorption, morphology, molecular structure, and chemical bonds, as well as the elemental and chemical states of PDINH/TiO 2 organic-inorganic hybrid. The interfaces between PDINH and TiO 2 , which largely determine photocatalytic performance, is also analyzed systematically. Furthermore, charge density difference (Δρ) is used to analyze the electron-ion interactions of PDINH and TiO 2 , and reveals that substantial charge transfer occurs from PDINH to TiO 2 . Copyright © 2018. Published by Elsevier Inc.

Synthesis, structure and photocatalytic activity of calcined Mg-Al-Ti-layered double hydroxides

Energy Technology Data Exchange (ETDEWEB)

Hosni, Khaled; Abdelkarim, Omar; Srasra, Ezzeddine [Centre National des Recherches en Sciences des Matériaux (CNRSM), Soliman (Turkey); Frini-Srasra, Najoua [Faculté des Sciences de Tunis (FST), Tunis (Turkey)

2015-01-15

Mg-Al-Ti layered double hydroxides (LDH), consisting of di-, tri- and tetra-valent cations with different Al{sup 3+}/Ti{sup 4+} ratio, have been synthesized by co-precipitation which was demonstrated as efficient visible-light photocatalysts. The structure and chemical composition of the compound were characterized by PXRD, FT-IR, SAA, N{sub 2} adsorption-desorption isotherms, and DSC techniques. It is found that no hydrotalcites structure were formed for Ti{sup 4+}/(Ti{sup 4+}+ Al{sup 3+})>0.5 and the substitution of Ti(IV) for Al(III) in the layer increases the thermal stability of the resulting LDH materials. The calcined sample containing titanium showed relatively high adsorption capacity for MB as compared to that without titanium. Results show that the pseudo-second-order kinetic model and the Langmuir were found to correlate the experimental data well. The photocatalytic activity was evaluated for the degradation of the methylene blue. The photocatalytic activity increased with the increase of the Al/Ti cationic ratio. 71% of the dye could be removed by the Mg/Al/Ti-LDH with the cationic ratio Al/Ti=0 : 1 and calcined at 500 .deg. C.

Reduction of vascular artifact on T1-weighted images of the brain by using three-dimensional double IR fast spoiled gradient echo recalled acquisition in the steady state (FSPGR) at 3.0 Tesla

International Nuclear Information System (INIS)

Fujiwara, Yasuhiro; Yamaguchi, Isao; Ookoshi, Yusuke; Ootani, Yuriko; Matsuda, Tsuyoshi; Ishimori, Yoshiyuki; Hayashi, Hiroyuki; Miyati, Tosiaki; Kimura, Hirohiko

2007-01-01

The purpose of this study was to decrease vascular artifacts caused by the in-flow effect in three-dimensional inversion recovery prepared fast spoiled gradient recalled acquisition in the steady state (3D IR FSPGR) at 3.0 Tesla. We developed 3D double IR FSPGR and investigated the signal characteristics of the new sequence. The 3D double IR FSPGR sequence uses two inversion pulses, the first for obtaining tissue contrast and the second for nulling vascular signal, which is applied at the time of the first IR period at the neck region. We have optimized scan parameters based on both phantom and in-vivo study. As a result, optimized parameters (1st TI=700 ms, 2nd TI=400 ms) successfully have produced much less vessel signal at reduction than conventional 3D IR FSPGR over a wide imaging range, while preserving the signal-to-noise ratio (SNR) and gray/white matter contrast. Moreover, the decreased artifact was also confirmed by visual inspection of the images obtained in vivo using those parameters. Thus, 3D double IR FSPGR was a useful sequence for the acquisition of T1-weighted images at 3.0 Tesla. (author)

Bi2Se3/CdS/TiO2 hybrid photoelectrode and its band-edge levels

International Nuclear Information System (INIS)

Zhang, Qi; Su, Jun; Zhang, Xianghui; Li, Jian; Zhang, Aiqing; Gao, Yihua

2012-01-01

Highlights: ► CVD synthesis of Bi 2 Se 3 nanoparticles. ► Bi 2 Se 3 and CdS co-sensitized TiO 2 nanorod arrays electrode was assembled by CVD. ► Direct physical contact heterojunctions were formed at the interfaces of electrode. ► Cascade structure of band-edge levels was formed in Bi 2 Se 3 /CdS/TiO 2 electrode. - Abstract: Bismuth selenide (Bi 2 Se 3 ) was chosen as the sensitizer to TiO 2 nanorod (NR) arrays photoelectrode to harvest infrared (IR) light for its narrow band gap. For utilizing more amount of IR solar energy, Bi 2 Se 3 nanoparticles (NPs) were grown up to a relative larger grain size. And, a cadmium sulfide (CdS) NPs intermediate layer was introduced to help, to coordinate, the structure of band-edge levels in Bi 2 Se 3 /CdS/TiO 2 electrode. Here, a chemical vapor deposition (CVD) strategy was introduced to assemble this kind of composite photoelectrode. And a cascade structure of band-edge levels constructed in it when achieving electrostatic equilibrium in Na 2 S/Na 2 SO 3 aqueous solution electrolyte revealed by electrochemical analysis method, which will facilitate the hydrogen generation.

PHOTODEGRADATION OF ALIZARIN S DYE USING TiO2-ZEOLITE AND UV RADIATION

Directory of Open Access Journals (Sweden)

Karna Wijaya

2010-06-01

Full Text Available An investigation of Alizarin S photodegradation using TiO2-zeolite and UV radiation was performed. TiO2-zeolite was prepared by dispersing oligocations of titanium into suspension of zeolite. The suspension was stirred and then filtered to separate the solid phase from the filtrate. the solid phase was calcined by microwave oven at 800 Watt for 5 minutes to convert the oligocations into its oxide forms. The calcined product and unmodified zeolite were characterized using x-ray diffractometry, FT-IR spectrophotometry, X-ray fluorescence and gas sorption analysis methods to determine their physicochemical properties. Photocatalytic activity of TiO2-zeolite was tested on Alizarin S solution using following method: 50 mg of zeolite was dispersed into 25 mL of 10-4 M Alizarin S. The dispersion was irradiated using 365 nm UV light at room temperature on various irradiation times, i.e. 10, 20, 30, 40 and 60 minutes. At certain irradiation time, the dispersion was filtered and the filtrate was then analyzed its concentration using UV-Vis spectrophotometry method. Characterization results exhibited that the formation of TiO2 on internal as well as external surfaces of zeolite could not be detected  with x-ray diffractometry and FT-IR spectrophotometry, however determination of titanium using x-ray fluorescence analysis on the calcined product showed that the concentration of titanium was much higher than zeolite (0.22% on zeolite and 12.08% on TiO2-zeolite. Gas sorption analysis result indicated that the the calcination  resulted in the increase of specific surface area (16,31 m2/g on zeolite and 100.96 m2/g on TiO2-zeolite as well as total pore volume of calcined product (13.34 mL/Å/g on zeolite and 57.54 mL/Å/g on TiO2-zeolite. The result of photocatalytic activitiy study showed that ca 99 % of Alizarin S was degraded by TiO2-zeolite after UV irradiation for 60 min.   Keywords: TiO2-zeolite, photocatalytic, Alizarin S.

Application of nitrogen-doped TiO{sub 2} nano-tubes in dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Tran, Vy Anh; Truong, Trieu Thinh; Phan, Thu Anh Pham; Nguyen, Trang Ngoc [Faculty of Chemistry, University of Science, Vietnam National University, Ho Chi Minh City (Viet Nam); Huynh, Tuan Van [Faculty of Physics and Engineering Physics, University of Science, Vietnam National University, Ho Chi Minh City (Viet Nam); Agresti, Antonio; Pescetelli, Sara [CHOSE (Centre for Hybrid and Organic Solar Energy), Department of Electronic Engineering, University of Rome Tor Vergata (Italy); Le, Tien Khoa [Faculty of Chemistry, University of Science, Vietnam National University, Ho Chi Minh City (Viet Nam); Di Carlo, Aldo [CHOSE (Centre for Hybrid and Organic Solar Energy), Department of Electronic Engineering, University of Rome Tor Vergata (Italy); Lund, Torben [Department of Science and Environment, Roskilde University, DK-4000 (Denmark); Le, So-Nhu [Faculty of Chemistry, University of Science, Vietnam National University, Ho Chi Minh City (Viet Nam); Nguyen, Phuong Tuyet, E-mail: ngtuyetphuong@gmail.com [Faculty of Chemistry, University of Science, Vietnam National University, Ho Chi Minh City (Viet Nam)

2017-03-31

Highlights: • N-doped TiO{sub 2} nanotubes are synthesized by alkaline hydrothermal and reflux method. • Formation of TiO{sub 2} nanotube morphology and anatase phase is shown by TEM, XRD, Raman. • Coordination of NH{sub 4}{sup +} via Ti−O−NH{sub 4}{sup +} or H{sub 4}N{sup +}−Ti−O bonds is indicated by FT-IR and XPS. • Blocking effect of N-doped toward electron transfer on TiO{sub 2} anode is studied by CV. • N-doped TiO{sub 2} improved DSC performance up to 30–40% mainly due to an increase in J{sub sc}. - Abstract: Our research aimed to improve the overall energy conversion efficiency of DSCs by applying nitrogen-doped TiO{sub 2} nano-tubes (N-TNT) for the preparation of DSCs photo-anodes. The none-doped TiO{sub 2} nano-tubes (TNTs) were synthesized by alkaline hydrothermal treatment of Degussa P25 TiO{sub 2} particles in 10 M NaOH. The nano-tubes were N-doped by reflux in various concentrations of NH{sub 4}NO{sub 3}. The effects of nitrogen doping on the structure, morphology, and crystallography of N-TNT were analyzed by transmission electron microscopy (TEM), infrared spectroscopy (IR), Raman spectroscopy, and X-ray photoelectron spectra (XPS). DSCs fabricated with doped N-TNT and TNT was characterized by J-V measurements. Results showed that nitrogen doping significantly enhanced the efficiency of N-TNT cells, reaching the optimum value (η = 7.36%) with 2 M nitrogen dopant, compared to η = 4.75% of TNT cells. The high efficiency of the N-TNT cells was attributed to increased current density due to the reduction of dark current in the DSCs.

Synthesis and Isolation of the Titanium-Scandium Endohedral Fullerenes-Sc2 TiC@Ih -C80 , Sc2 TiC@D5h -C80 and Sc2 TiC2 @Ih -C80 : Metal Size Tuning of the Ti(IV) /Ti(III) Redox Potentials.

Science.gov (United States)

Junghans, Katrin; Ghiassi, Kamran B; Samoylova, Nataliya A; Deng, Qingming; Rosenkranz, Marco; Olmstead, Marilyn M; Balch, Alan L; Popov, Alexey A

2016-09-05

The formation of endohedral metallofullerenes (EMFs) in an electric arc is reported for the mixed-metal Sc-Ti system utilizing methane as a reactive gas. Comparison of these results with those from the Sc/CH4 and Ti/CH4 systems as well as syntheses without methane revealed a strong mutual influence of all key components on the product distribution. Whereas a methane atmosphere alone suppresses the formation of empty cage fullerenes, the Ti/CH4 system forms mainly empty cage fullerenes. In contrast, the main fullerene products in the Sc/CH4 system are Sc4 C2 @C80 (the most abundant EMF from this synthesis), Sc3 C2 @C80 , isomers of Sc2 C2 @C82 , and the family Sc2 C2 n (2 n=74, 76, 82, 86, 90, etc.), as well as Sc3 CH@C80 . The Sc-Ti/CH4 system produces the mixed-metal Sc2 TiC@C2 n (2 n=68, 78, 80) and Sc2 TiC2 @C2 n (2 n=80) clusterfullerene families. The molecular structures of the new, transition-metal-containing endohedral fullerenes, Sc2 TiC@Ih -C80 , Sc2 TiC@D5h -C80 , and Sc2 TiC2 @Ih -C80 , were characterized by NMR spectroscopy. The structure of Sc2 TiC@Ih -C80 was also determined by single-crystal X-ray diffraction, which demonstrated the presence of a short Ti=C double bond. Both Sc2 TiC- and Sc2 TiC2 -containing clusterfullerenes have Ti-localized LUMOs. Encapsulation of the redox-active Ti ion inside the fullerene cage enables analysis of the cluster-cage strain in the endohedral fullerenes through electrochemical measurements. © 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

VCSEL-based gigabit IR-UWB link for converged communication and sensing applications in optical metro-access networks

DEFF Research Database (Denmark)

Pham, Tien Thang; Gibbon, Timothy Braidwood; Tafur Monroy, Idelfonso

2012-01-01

We report on experimental demonstration of an impulse radio ultrawideband (IR-UWB) based converged communication and sensing system. A 1550-nm VCSEL-generated IR-UWB signal is used for 2-Gbps wireless data distribution over 800-m and 50-km single mode fiber links which present short-range in-buil...... application, paving the way forward for the development and deployment of converged UWB VCSEL-based technologies in access and in-building networks of the future.......We report on experimental demonstration of an impulse radio ultrawideband (IR-UWB) based converged communication and sensing system. A 1550-nm VCSEL-generated IR-UWB signal is used for 2-Gbps wireless data distribution over 800-m and 50-km single mode fiber links which present short-range in......-building and long-reach access network applications. The IR-UWB signal is also used to simultaneously measure the rotational speed of a blade spinning between 18 and 30 Hz. To the best of our knowledge, this is the very first demonstration of a simultaneous gigabit UWB telecommunication and wireless UWB sensing...

The research on the surface photovoltaic properties of porphyrin affected by nano-TiO2

International Nuclear Information System (INIS)

Li Ziheng; Wang Dejun; Shi Yingyan; Wang Ping; Wang Xingqiao

2005-01-01

The degeneration of energy level of α, β, γ, δ-tetrahydroxylphenylporphyrin (THPP) and red shift of the photovoltage peaks of THPP are observed as the size of nano-TiO 2 decreasing using surface photovoltage (SPV) technique, while that of α, β, γ, δ-tetraphenylporphyrin (TPP) have little change. The reason for that is the existence of hydroxyls of THPP, which interact with the surface of nano-TiO 2 . This difference was also demonstrated by IR spectrum

Ar ir CO2 plazma modifikuota aktyvintoji anglis acetono ir cikloheksano adsorbcijai

Directory of Open Access Journals (Sweden)

Piotr PIETROWSKI

2012-06-01

Full Text Available Žemos temperatūros plazmos poveikis, leidžiantis valdyti daugelio rūšių medžiagų, pvz., polimerų, metalų, anglies, paviršiaus savybes, šiuo metu yra tiriamas daugelyje mokslo sričių. Aktyvintoji  anglis (AC dėl savo fizikinių ir cheminių savybių naudojama kaip struktūrinis elementas dujų filtruose, kurie adsorbuodami daugelį skirtingų garų iš užteršto oro apsaugo kvėpavimo takus. Gerai žinoma, kad įvairios AC paviršiaus funkcinės grupės lemia jų hidrofobinę / hidrofilinę elgseną. Šame straipsnyje pristatomi pirminiai tyrimai, susiję su žemos temperatūros plazmos poveikiu komercinei aktyvintajai angliai. Aktyvintoji anglis buvo granuliuojama ir dedama į žemos temperatūros plazmos  rotacinę bandymų kamerą. Kamera buvo užpildoma atitinkamomis reaktyviosiomis dujomis. Plazmos poveikis buvo tiriamas nustatant aktyvintosios anglies paviršiaus dviejų pasirinktų rūšių organinių garų adsorbcijos izotermas, taip pat stebint šių garų adsorbcijos dinamiką ant dujų filtro, pagaminto iš plazma aktyvintos anglies. Remiantis gautais rezultatais, galima daryti išvadą, kad žemos temperatūros plazmos technologija gali būti taikoma aktyvintosios anglies savybėms pagerinti užtikrinant geresnę žemos temperatūros organinių garų adsorbciją.DOI: http://dx.doi.org/10.5755/j01.ms.18.2.1919

Short-length and high-density TiO{sub 2} nanorod arrays for the efficient charge separation interface in perovskite solar cells

Energy Technology Data Exchange (ETDEWEB)

Xiao, Guannan; Shi, Chengwu, E-mail: shicw506@foxmail.com; Zhang, Zhengguo; Li, Nannan; Li, Long

2017-05-15

�� Preparation of TiO{sub 2} nanorod array with length of 70 nm and density of 1000 µm{sup −2}. • Influence of annealing temperatures on the -OH content of TiO{sub 2} nanorod arrays. • Preparation of over-500 nm-thickness CH{sub 3}NH{sub 3}PbI{sub 3−x}Br{sub x} absorber layer. • Combination of short-length TiO{sub 2} nanorod array and high-thickness perovskite layer. • The best and average PCE with TiO{sub 2} array of 15.93% and 13.41±2.52% at 50–54% RH.

Electric field changes on Au nanoparticles on semiconductor supports--the molecular voltmeter and other methods to observe adsorbate-induced charge-transfer effects in Au/TiO2 nanocatalysts.

Science.gov (United States)

McEntee, Monica; Stevanovic, Ana; Tang, Wenjie; Neurock, Matthew; Yates, John T

2015-02-11

Infrared (IR) studies of Au/TiO2 catalyst particles indicate that charge transfer from van der Waals-bound donor or acceptor molecules on TiO2 to or from Au occurs via transport of charge carriers in the semiconductor TiO2 support. The ΔνCO on Au is shown to be proportional to the polarizability of the TiO2 support fully covered with donor or acceptor molecules, producing a proportional frequency shift in νCO. Charge transfer through TiO2 is associated with the population of electron trap sites in the bandgap of TiO2 and can be independently followed by changes in photoluminescence intensity and by shifts in the broad IR absorbance region for electron trap sites, which is also proportional to the polarizability of donors by IR excitation. Density functional theory calculations show that electron transfer from the donor molecules to TiO2 and to supported Au particles produces a negative charge on the Au, whereas the transfer from the Au particles to the TiO2 support into acceptor molecules results in a positive charge on the Au. These changes along with the magnitudes of the shifts are consistent with the Stark effect. A number of experiments show that the ∼3 nm Au particles act as "molecular voltmeters" in influencing ΔνCO. Insulator particles, such as SiO2, do not display electron-transfer effects to Au particles on their surface. These studies are preliminary to doping studies of semiconductor-oxide particles by metal ions which modify Lewis acid/base oxide properties and possibly strongly modify the electron-transfer and catalytic activity of supported metal catalyst particles.

Highly-efficient photocatalytic degradation of methylene blue by PoPD-modified TiO 2 nanocomposites due to photosensitization-synergetic effect of TiO2 with PoPD.

Science.gov (United States)

Yang, Chuanxi; Dong, Wenping; Cui, Guanwei; Zhao, Yingqiang; Shi, Xifeng; Xia, Xinyuan; Tang, Bo; Wang, Weiliang

2017-06-21

Poly-o-phenylenediamine modified TiO 2 nanocomposites were successfully synthesized via an 'in situ' oxidative polymerization method. The modified nanocomposites were characterized by BET, XRD, TEM, FT-IR, TGA, XPS, EA and UV-Vis DRS. The photocatalytic degradation of methylene blue was chosen as a model reaction to evaluate the photocatalytic activities of TiO 2 and PoPD/TiO 2 . The results indicated that PoPD/TiO 2 nanocomposites exhibited good photocatalytic activity and stability. The photocatalytic activity of PoPD/TiO 2 increased as the initial pH increased because of electrostatic adsorption between the photocatalyst and MB as well as the generation of ·OH, whereas it exhibited an earlier increasing and later decreasing trend as the concentration of the photocatalyst increased owing to the absorption of visible light. The photocatalytic stability of the PoPD/TiO 2 nanocomposite was dependent on the stability of its structure. Based on radical trapping experiments and ESR measurements, the origin of oxidizing ability of PoPD/TiO 2 nanocomposites on photocatalytic degradation of MB was proposed, which taking into account of ·OH and ·O 2 - were the first and second important ROS, respectively. The possible photocatalytic mechanism and photocatalytic activity enhanced mechanism has been proposed, taking into account the photosensitization effect and synergetic effect of TiO 2 with PoPD.

As-cast microstructures of Ti-11 Al- xC alloys

Institute of Scientific and Technical Information of China (English)

无

2001-01-01

Presents the investigation of as-cast microstructures of high temperature α + α2 titanium alloys matrix composites reinforced by particles and fabricated using a reaction synthesis method by XRD, OM and SEM which reveals that the matrix transformed into single phase α2 from two phases α + α2 and reinforcing phases become Ti3A1C and TiC from single phase TiC as C content increases to a critical value, and Ti3AlC precipitates during solidification processing and points out that the norphologies of TiC and Ti3AlC are of short-lath shape and near spherical shape, respectively, and lattice parameters of matrix α2 increase with the increasing of C content, but the lattice parameter of reinforcing phase TiC is lower than standard lattice parameter of TiC due to the C defection in TiC.

Neariminio žemės dirbimo ir augalinių liekanų poveikis žieminių kviečių agroekosistemos komponentams

OpenAIRE

Leimonaitė, Laura

2012-01-01

Žemės dirbimas yra vienas iš daugiausia darbo, energetinių bei laiko sąnaudų reikalaujančių technologinių darbų auginant augalus. Todėl įvairaus intensyvumo žemės dirbimo sistemų nustatymas, kurios nemažindamos žemės ūkio augalų derliaus neblogintų dirvožemio agrocheminių savybių, yra svarbus ir ekonomine, ir aplinkosaugine prasme. Pasikliaujama ribotu paviršiaus purenimu, ražienine sėja. Taip sutaupomos lėšos, mažiau gaištama laiko dirvai ruošti. Dėl gilaus ir pastovaus žemės dirbimo gali ma...

FAST VARIABILITY AND MILLIMETER/IR FLARES IN GRMHD MODELS OF Sgr A* FROM STRONG-FIELD GRAVITATIONAL LENSING

Energy Technology Data Exchange (ETDEWEB)

Chan, Chi-kwan; Psaltis, Dimitrios; Özel, Feryal; Marrone, Daniel [Steward Observatory and Department of Astronomy, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Medeiros, Lia [Department of Physics, Broida Hall, University of California, Santa Barbara, Santa Barbara, CA 93106 (United States); Sadowski, Aleksander [MIT Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Narayan, Ramesh, E-mail: chanc@email.arizona.edu [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2015-10-20

We explore the variability properties of long, high-cadence general relativistic magnetohydrodynamic (GRMHD) simulations across the electromagnetic spectrum using an efficient, GPU-based radiative transfer algorithm. We focus on both standard and normal evolution (SANE) and magnetically arrested disk (MAD) simulations with parameters that successfully reproduce the time-averaged spectral properties of Sgr A* and the size of its image at 1.3 mm. We find that the SANE models produce short-timescale variability with amplitudes and power spectra that closely resemble those inferred observationally. In contrast, MAD models generate only slow variability at lower flux levels. Neither set of models shows any X-ray flares, which most likely indicates that additional physics, such as particle acceleration mechanisms, need to be incorporated into the GRMHD simulations to account for them. The SANE models show strong, short-lived millimeter/infrared (IR) flares, with short (≲1 hr) time lags between the millimeter and IR wavelengths, that arise from the combination of short-lived magnetic flux tubes and strong-field gravitational lensing near the horizon. Such events provide a natural explanation for the observed IR flares with no X-ray counterparts.

Darbo metu susenėjusių ir po suvirinimo termiškai apdorotų plieno 5 % Cr-0,5 % Mo virintinių jungčių struktūra ir savybės

Directory of Open Access Journals (Sweden)

Vigantas KUMŠLYTIS

2012-06-01

Full Text Available Straipsnyje nagrinėjamos suvirintos ir termiškai apdorotos chromo ir molibdeno (5 % Cr – 0,5 % Mo grupės plieno vamzdžių jungtys. Taip pat pateikiami ir palyginami ilgą laiką aukštoje temperatūroje eksploatuoto ir naujo chromo ir molibdeno plieno vamzdžio struktūra ir mechaninių savybių tyrimai. Eksploatuoto metalo tyrimams buvo panaudotas 530 °C temperatūroje 100 000 valandų dirbęs plieninis vamzdis. Tyrimais siekiama nustatyti 5 % Cr – 0,5% Mo grupės plienų suvirintųjų jungčių mechaninių savybių ir terminio apdorojimo parametrų tarpusavio priklausomybes. Atlikti suvirintų bandinių struktūros radiografiniai, mechaninių savybių, lūžių analizės ir mikrostruktūrų tyrimai. Nustatyta, kad chromo ir molibdeno plienų virintinių jungčių vidiniams įtempiams mažinti turi būti taikomas tik terminis apdorojimas. Kiti įtempių mažinimo metodai šiems plienams yra nepriimtini. Nustatyta, kad 5 % Cr – 0,5 % Mo plienų virintinių jungčių terminio apdorojimo temperatūros ir laiko parametro P reikšmė neturi viršyti 20,5. Viršijus šią reikšmę vyksta struktūros degradacijos procesas, karbidai pamažu transformuojasi į M23C6 karbidus, koaguliuoja ferito grūdelių ribose, sudaro karbidų kolonijas ar jungiasi į ilgus vientisus junginius. Smulkių, dispersiškų karbidų struktūroje nelieka. Taip pat mažėja jungties metalo takumo stipris ir smūginis tąsumas.DOI: http://dx.doi.org/10.5755/j01.ms.18.2.1911

PREPARATION AND CHARACTERIZATION OF TiO2-ZEOLITE AND ITS APPLICATION TO DEGRADE TEXTILLE WASTEWATER BY PHOTOCATALYTIC METHOD

Directory of Open Access Journals (Sweden)

Yeslia Utubira

2010-06-01

Full Text Available The preparation of titanium oxide-zeolite composite (TiO2-zeolite has been done. Preparation was initiated by dispersing oligocation of titanium solution into suspension of natural zeolite. The suspension was stirred and then filtered to separate the solid phase from the filtrate. The solid phase was heated by microwave oven to convert the oligocations into its oxide forms and the resulting material (called as TiO2-zeolite then was used to photodegrade the wastewater of PT.Jogjatex The TiO2-zeolite and unmodified zeolite were characterized using X-ray diffractometry, FT-IR spectro-photometry, X-ray fluorescence (XRF and gas sorption analysis (GSA methods to determine their physicochemical properties. Photocatalytic activity of TiO2-Zeolite was tested by exposing the suspension of TiO2-Zeolite/wastewater by the UV light of 366 nm at room temperature for 15 - 75 minutes. Characterization results exhibited that the formation of TiO2 on internal as well as external surfaces of Zeolite could not be detected  with X-ray diffractometry as well as  FT-IR spectrophotometry, however elemental analysis result with XRF indicated that titanium concentration in zeolite increased due to the inclusion, i.e from 0.26% (w/w in zeolite to 2.80% (w/w in TiO2-zeolite. Characterization result by GSA exhibited the increased of specific surface area from 19.57 m2/g in zeolite to 67.96 m2/g in TiO2-zeolite; total pore volume from 20.64 x 10-3 mL/g in zeolite to 49.561 x 10-3 mL/g in TiO2-Zeolite; pore radius average decreased from 21.10 Å in zeolite to 14.58 Å in TiO2-zeolite. Photocatalytic activity test of TiO2-zeolite on wastewater of PT. Jogjatex showed that UV radiation for 75 minutes on the mixture of TiO2-zeolite and wastewater resulted in the decreased of  COD number up to 57.85%. Meanwhile the sorption study showed that zeolite and TiO2-zeolite could decrease COD number of wastewater up to 43.95% and 57.85%, respectively.   Keywords: TiO2-zeolite

Caracterização textural e estrutural de V2O5/TiO2 obtidos via sol-gel: comparação entre secagem convencional e supercrítica Textural and structural characterization of V2O5/TiO2 catalysts obtained by the sol-gel method: comparison between conventional and supercritical drying

Directory of Open Access Journals (Sweden)

Cristiane B. Rodella

2002-05-01

Full Text Available This work describes a modified sol-gel method for the preparation of V2O5/TiO2 catalysts. The samples have been characterized by N2 adsorption at 77K, x-ray diffractometry (XRD and Fourier Transform Infrared (FT-IR. The surface area increases with the vanadia loading from 24 m² g-1, for pure TiO2, to 87 m² g-1 for 9wt.% of V2O5. The rutile form is predominant for pure TiO2 but became enriched with anatase phase when vanadia loading is increased. No crystalline V2O5 phase was observed in the catalysts diffractograms. Two species of surface vanadium observed by FT-IR spectroscopy a monomeric vanadyl and polymeric vanadates, the vanadyl/vanadate ratio remains practically constant.

Synthesis and characterization of Zn-Ti layered double hydroxide intercalated with cinnamic acid for cosmetic application

Science.gov (United States)

Li, Yong; Tang, Liping; Ma, Xinxu; Wang, Xinrui; Zhou, Wei; Bai, Dongsheng

2017-08-01

The use of sunscreen is recently growing and their efficacy and safety must be taken into account since they are applied on the skin frequently. In this work, an organic ultraviolet (UV) ray absorbent, cinnamic acid (CA) was intercalated into Zn-Ti layered double hydroxide (LDH) by anion-exchange reaction. ZnTi-CA-LDH, a new type of host-guest UV-blocking material has been synthesized. Detailed structural and surface morphology of ZnTi-CA-LDH were characterized by XRD, FT-IR, SEM and TEM. ZnTi-CA-LDH exhibits a superior UV blocking ability compared to pure CA and ZnTi-CO3-LDH. The thermal stability of the intercalated ZnTi-CA-LDH was investigated by TG-DTA, which showed that the thermostability of CA was markedly enhanced after intercalation into ZnTi-CO3-LDH. The EPR data showed greatly decreased photocatalytic activity compared to common inorganic UV blocking agents TiO2 and ZnO. Furthermore, the sample was formulated in a sunscreen cream to study the matrix protective effect towards UV rays.

A facile approach to fabrication of novel CeO2–TiO2 core–shell nanocomposite leads to excellent UV-shielding ability and lower catalytic activity

International Nuclear Information System (INIS)

Bahadur, Newaz Mohammed; Kurayama, Fumio; Furusawa, Takeshi; Sato, Masahide; Siddiquey, Iqbal Ahmed; Hossain, Md. Mufazzal; Suzuki, Noboru

2013-01-01

This study reports the development of a fast and facile route for the synthesis of novel CeO 2 –TiO 2 core–shell nanocomposite particles using microwave (MW) irradiation of the mixture of commercial CeO 2 , titanium-tetra-n-butoxide (TBOT) and aqueous ammonia. Solutions of TBOT in ethanol and ammonia were mixed with dispersed CeO 2 nanoparticles in ethanol, and the mixture was rapidly MW irradiated at 70 °C for 2 min. The resulting nanocomposite particles were characterized in terms of phase, shell thickness, composition, surface charge, morphology, and chemical state of the elements by XRD, TEM, XPS, SEM, Zeta potential analyzer, XRF, and FT-IR. Conventional methods of the synthesis of CeO 2 –TiO 2 nanocomposite require a long time, and TiO 2 is rarely found as a coated material. In contrast, the MW method was able to synthesize CeO 2 –TiO 2 core–shell nanocompsite particles within a very short time. CeO 2 –TiO 2 nanocomposite particles were fairly unaggregated with an average titania layer thickness of 2–5 nm. The obtained nanocomposites retained the crystalline cubic phase of CeO 2 , and the phase of coated TiO 2 was amorphous. The catalytic activities of uncoated and TiO 2 -coated CeO 2 nanoparticles for the oxidation of organic compounds were evaluated by the degradation study of methylene blue in air atmosphere at 403 K. The enhanced UV-shielding ability and visible transparency of the nanocomposite obtained by UV visible spectroscopic measurements suggested that the core–shell material has novel characteristics for using as a sunscreen material.

Augimo reguliatoriaus trineksapak-etilo ir jo mišinių įtaka žieminių kviečių stiebų biometriniams rodikliams

OpenAIRE

Auškalnienė, Ona

2005-01-01

Augimo reguliatoriai naudojami javų išgulimui išvengti ir užima svarbią vietą javų auginimo technologijoje. Augimo reguliatorių bei jų mišinių ir derinių efektyvumo tyrimai daryti 2002-2003 metais Lietuvos žemdirbystės instituto Dirvožemio ir augalininkystės skyriaus sėjomainų žieminių kviečių 'Širvinta' laukuose. Dirvožemis - giliau karbonatingas sekliau glėjiškas rudžemis, lengvas priemolis, drenuotas, neutralaus rūgštumo. Žieminiai kviečiai purkšti giberalinu sintezės inhibitoriais cykocel...

Preparation and Characterization of TiO2/CdS Layers as Potential Photoelectrocatalytic Materials

Directory of Open Access Journals (Sweden)

Teofil-Danut Silipas

2011-01-01

Full Text Available The TiO2/CdS semiconductor composites were prepared on
indium tin oxide (ITO substrates in di®erent mass proportions via wet-chemical techniques using bi-distilled water, acetyl-acetone, poly-propylene-glycol and Triton X-100 as additives. The composite layers were annealed in normal conditions at the temperature of 450±C, 120 min. with a rate of temperature increasing of 5±C/min. The structural and optical properties of all the TiO2/CdS ayers were characterized by X-ray di®raction, UV-VIS spectroscopy, spectrofluorimetry and FT/IR microscopy. The microstructural properties of the deposited TiO2/CdS layers can be modi¯ed by varying the mass proportions of TiO2:CdS. The good crystallinity level and the high optical adsorption of
the TiO2/CdS layers make them attractive for photoelectrochemical cell applications.

IRS/TUEV activities during the licensing procedure. Safety assessment and preexamination

International Nuclear Information System (INIS)

Fendler, H.

1976-01-01

Short summary about the IRS/TUEV activities in the licensing procedure for a nuclear power plant: work for assessments, for pre-examination and approval specifications and drawings and for the quality control, time and the manpower necessary for this work. (orig./HP) [de

Preparation and Photocatalytic Activity of Nitrogen-doped Nano TiO2/Tourmaline Composites

Directory of Open Access Journals (Sweden)

LIU Xin-wei

2016-06-01

Full Text Available Using Ti(OC4H94 as precursor, CO(NH22 as nitrogen source, tourmaline as support, the nitrogen-doped nano TiO2/tourmaline composites were synthesized by sol-gel method with ultrasound assisted.The structure and performance of composites were characterized by XRD, FT-IR, UV-Vis DRS, SEM, EDS.The effects of calcining temperature, nitrogen-doped content, tourmaline amount, catalyst system on the photocatalytic activity of nitrogen-doped nano TiO2/tourmaline composites were studied.The results show that the photocatalytic activity of nitrogen-doped nano TiO2/tourmaline composites calcined under 500℃, the nitrogen doped amount of 5% (mole fraction, tourmaline added in an amount of 10% (mass fraction, catalyst dosage of 3g/L, under 500W UV light irradiation conditions, the photocatalytic degradation effect of TNT(10mg/L is the best, and has a good recycling performance.

Food-grade TiO2 is trapped by intestinal mucus in vitro but does not impair mucin O-glycosylation and short-chain fatty acid synthesis in vivo: implications for gut barrier protection.

Science.gov (United States)

Talbot, Pauline; Radziwill-Bienkowska, Joanna M; Kamphuis, Jasper B J; Steenkeste, Karine; Bettini, Sarah; Robert, Véronique; Noordine, Marie-Louise; Mayeur, Camille; Gaultier, Eric; Langella, Philippe; Robbe-Masselot, Catherine; Houdeau, Eric; Thomas, Muriel; Mercier-Bonin, Muriel

2018-06-19

Titanium dioxide (TiO 2 ) particles are commonly used as a food additive (E171 in the EU) for its whitening and opacifying properties. However, the risk of gut barrier disruption is an increasing concern because of the presence of a nano-sized fraction. Food-grade E171 may interact with mucus, a gut barrier protagonist still poorly explored in food nanotoxicology. To test this hypothesis, a comprehensive approach was performed to evaluate in vitro and in vivo interactions between TiO 2 and intestinal mucus, by comparing food-grade E171 with NM-105 (Aeroxyde P25) OECD reference nanomaterial. We tested E171-trapping properties of mucus in vitro using HT29-MTX intestinal epithelial cells. Time-lapse confocal laser scanning microscopy was performed without labeling to avoid modification of the particle surface. Near-UV irradiation of E171 TiO 2 particles at 364 nm resulted in fluorescence emission in the visible range, with a maximum at 510 nm. The penetration of E171 TiO 2 into the mucoid area of HT29-MTX cells was visualized in situ. One hour after exposure, TiO 2 particles accumulated inside "patchy" regions 20 µm above the substratum. The structure of mucus produced by HT29-MTX cells was characterized by MUC5AC immunofluorescence staining. The mucus layer was thin and organized into regular "islands" located approximately 20 µm above the substratum. The region-specific trapping of food-grade TiO 2 particles was attributed to this mucus patchy structure. We compared TiO 2 -mediated effects in vivo in rats after acute or sub-chronic oral daily administration of food-grade E171 and NM-105 at relevant exposure levels for humans. Cecal short-chain fatty acid profiles and gut mucin O-glycosylation patterns remained unchanged, irrespective of treatment. Food-grade TiO 2 is trapped by intestinal mucus in vitro but does not affect mucin O-glycosylation and short-chain fatty acid synthesis in vivo, suggesting the absence of a mucus barrier impairment under "healthy gut

PIIID-formed (Ti, O)/Ti, (Ti, N)/Ti and (Ti, O, N)/Ti coatings on NiTi shape memory alloy for medical applications

Energy Technology Data Exchange (ETDEWEB)

Sun Tao, E-mail: taosun@hotmail.com.hk [Department of Mechanical Engineering, University of Hong Kong, Pokfulam Road (Hong Kong); Institute of Microelectronics, Agency for Science, Technology and Research (A-STAR) (Singapore); Wang Langping, E-mail: aplpwang@hit.edu.cn [State Key Lab of Advanced Welding and Joining, Harbin Institute of Technology (China); Wang Min; Tong Howang [Department of Mechanical Engineering, University of Hong Kong, Pokfulam Road (Hong Kong); Lu, William W. [Department of Orthopedics and Traumatology, University of Hong Kong, Sassoon Road (Hong Kong)

2012-08-01

(Ti, O)/Ti, (Ti, N)/Ti and (Ti, O, N)/Ti composite coatings were fabricated on NiTi shape memory alloy via plasma immersion ion implantation and deposition (PIIID). Surface morphology of samples was investigated using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Cross-sectional morphology indicated that the PIIID-formed coatings were dense and uniform. X-ray diffraction (XRD) was used to characterize the phase composition of samples. X-ray photoelectron spectroscopy (XPS) results showed that the surface of coated NiTi SMA samples was Ni-free. Nanoindentation measurements and pin-on-disc tests were carried out to evaluate mechanical properties and wear resistance of coated NiTi SMA, respectively. For the in vitro biological assessment of the composite coatings in terms of cell morphology and cell viability, osteoblast-like SaOS-2 cells and breast cancer MCF-7 cells were cultured on NiTi SMA samples, respectively. SaOS-2 cells attached and spread better on coated NiTi SMA. Viability of MCF-7 cells showed that the PIIID-formed composite coatings were noncytotoxic and coated samples were more biocompatible than uncoated samples. - Highlights: Black-Right-Pointing-Pointer PIIID-formed coatings were fabricated on NiTi SMA to improve its biocompatibility. Black-Right-Pointing-Pointer Microstructure, mechanical properties and biocompatibility of coatings were investigated. Black-Right-Pointing-Pointer All PIIID-formed composite coatings were noncytotoxic and cytocompatible.

UV/IR Filaments for High Resolution Novel Spectroscopic Interrogation of Plumes on Nuclear Materials

Science.gov (United States)

2016-06-01

Raman spectroscopy of plumes created by a laser filament. The molecules to be detected are excited by the short pulse IR pulse, while the co-propagating... spectroscopy of gas samples has been demonstrated in IR filaments [32], using the fs pulse of the filament (800 nm) to vibrationally excite the components...Petit. Isotope ratio determination of uranium by optical emission spectroscopy on a laser -produced plasma; basic investigation and analytical results

Probing surface sites of TiO2: reactions with [HRe(CO)5] and [CH3Re(CO)5].

Science.gov (United States)

Lobo-Lapidus, Rodrigo J; Gates, Bruce C

2010-10-04

Two carbonyl complexes of rhenium, [HRe(CO)(5)] and [CH(3)Re(CO)(5)], were used to probe surface sites of TiO(2) (anatase). These complexes were adsorbed from the gas phase onto anatase powder that had been treated in flowing O(2) or under vacuum to vary the density of surface OH sites. Infrared (IR) spectra demonstrate the variation in the number of sites, including Ti(+3)-OH and Ti(+4)-OH. IR and extended X-ray absorption fine structure (EXAFS) spectra show that chemisorption of the rhenium complexes led to their decarbonylation, with formation of surface-bound rhenium tricarbonyls, when [HRe(CO)(5)] was adsorbed, or rhenium tetracarbonyls, when [CH(3)Re(CO)(5)] was adsorbed. These reactions were accompanied by the formation of water and surface carbonates and removal of terminal hydroxyl groups associated with Ti(+3) and Ti(+4) ions on the anatase. Data characterizing the samples after adsorption of [HRe(CO)(5)] or [CH(3)Re(CO)(5)] determined a ranking of the reactivity of the surface OH sites, with the Ti(+3)-OH groups being the more reactive towards the rhenium complexes but the less likely to be dehydroxylated. The two rhenium pentacarbonyl probes provided complementary information, suggesting that the carbonate species originate from carbonyl ligands initially bonded to the rhenium and from hydroxyl groups of the titania surface, with the reaction leading to the formation of water and bridging hydroxyl groups on the titania. The results illustrate the value of using a family of organometallic complexes as probes of oxide surface sites.

KINETIC BEHAVIOR IN THE HYDROGENATION OF FURFURAL OVER IR CATALYSTS SUPPORTED ON TIO2

OpenAIRE

ROJAS, HUGO; MARTÍNEZ, JOSÉ J.; REYES, PATRICIO

2010-01-01

The kinetics of the liquid-phase hydrogenation of furfuraldehyde to furfuryl alcohol over Ir catalysts supported over TiO2 was studied in the temperature range of 323 to 373 K. The effect of furfural concentration, hydrogen pressure and the solvent effect were also studied. A high selectivity towards furfuryl alcohol was demonstrated. Initial rates describes the order global of the reaction. The experimental data could also be explained using the Langmuir-Hinshelwood model with of a single-si...

Electronic structure of layered ferroelectric high-k titanate Pr2Ti2O7

International Nuclear Information System (INIS)

Atuchin, V.V.; Gavrilova, T.A.; Grivel, J.-C.; Kesler, V.G.; Troitskaia, I.B.

2012-01-01

The spectroscopic parameters and electronic structure of binary titanate Pr 2 Ti 2 O 7 have been studied by IR-, Raman and X-ray photoelectron spectroscopy (XPS) for the powder sample prepared by solid state synthesis. The spectral features of valence band and all constituent element core levels have been considered. The Auger parameters of titanium and oxygen in Pr 2 Ti 2 O 7 have been determined as α Ti =872.8 and α O =1042.3 eV. Variations of cation–anion bond ionicity have been discussed using binding energy differences Δ Ti =(BE O 1s–BE Ti 2p 3/2 )=71.6 eV and Δ Pr =BE(Pr 3d 5/2 )−BE(O 1s)=403.8 eV as key parameters in comparison with those of other titanium- and praseodymium-bearing oxides. Highlights: ► Solid state synthesis of polar titanate Pr 2 Ti 2 O 7 . ► Structural and spectroscopic properties and electronic structure determination. ► Ti–O and Pr–O bonding analysis using Ti 2p 3/2 , Pr 3d 5/2 and O 1s core levels.

TiO2 nanofiber solid-state dye sensitized solar cells with thin TiO2 hole blocking layer prepared by atomic layer deposition

International Nuclear Information System (INIS)

Li, Jinwei; Chen, Xi; Xu, Weihe; Nam, Chang-Yong; Shi, Yong

2013-01-01

We incorporated a thin but structurally dense TiO 2 layer prepared by atomic layer deposition (ALD) as an efficient hole blocking layer in the TiO 2 nanofiber based solid-state dye sensitized solar cell (ss-DSSC). The nanofiber ss-DSSCs having ALD TiO 2 layers displayed increased open circuit voltage, short circuit current density, and power conversion efficiency compared to control devices with blocking layers prepared by spin-coating liquid TiO 2 precursor. We attribute the improved photovoltaic device performance to the structural integrity of ALD-coated TiO 2 layer and consequently enhanced hole blocking effect that results in reduced dark leakage current and increased charge carrier lifetime. - Highlights: • TiO 2 blocking locking layer prepared by atomic layer deposition (ALD) method. • ALD-coated TiO 2 layer enhanced hole blocking effect. • ALD blocking layer improved the voltage, current and efficiency. • ALD blocking layer reduced dark leakage current and increased electron lifetime

Electronic structure of layered ferroelectric high-k titanate Pr2Ti2O7

DEFF Research Database (Denmark)

Atuchin, V.V.; Gavrilova, T.A.; Grivel, Jean-Claude

2012-01-01

The spectroscopic parameters and electronic structure of binary titanate Pr2Ti2O7 have been studied by IR-, Raman and X-ray photoelectron spectroscopy (XPS) for the powder sample prepared by solid state synthesis. The spectral features of valence band and all constituent element core levels have...

Nanographite-TiO2 photoanode for dye sensitized solar cells

Science.gov (United States)

Sharma, S. S.; Sharma, Khushboo; Sharma, Vinay

2016-05-01

Nanographite-TiO2 (NG-TiO2) composite was successfully synthesized by the hydrothermal method and its performance as the photoanode for dye-sensitized solar cells (DSSCs) was investigated. Environmental Scanning electron microscope (E-SEM) micrographs show the uniform distribution of TiO2 nanoflowers deposited over nanographite sheets. The average performance characteristics of the assembled cell in terms of short-ciruit current density (JSC), open circuit voltage (VOC), fill factor (FF) and photoelectric conversion efficiency (η) were measured.

Solar photocatalytic degradation of isoproturon over TiO2/H-MOR composite systems

International Nuclear Information System (INIS)

Sharma, Mangalampalli V. Phanikrishna; Durgakumari, Valluri; Subrahmanyam, Machiraju

2008-01-01

The photocatalytic degradation and mineralization of isoproturon herbicide was investigated in aqueous solution containing TiO 2 over H-mordenite (H-MOR) photocatalysts under solar light. The catalysts are characterized by X-ray diffraction (XRD), UV-Vis diffused reflectance spectra (UV-Vis DRS), Fourier transform-infra red spectra (FT-IR) and scanning electron microscopy (SEM) techniques. The effect of TiO 2 , H-MOR support and different wt% of TiO 2 over the support on the photocatalytic degradation and influence of parameters such as TiO 2 loading, catalyst amount, pH and initial concentration of isoproturon on degradation are evaluated. 15 wt% TiO 2 /H-MOR composite is found to be optimum. The degradation reaction follows pseudo-first order kinetics and is discussed in terms of Langmuir-Hinshelwood (L-H) kinetic model. The extent of isoproturon mineralization studied with chemical oxygen demand (COD) and total organic carbon (TOC) measurements and ∼80% mineralization occurred in 5 h. A plausible mechanism is proposed based on the intermediates identified by liquid chromatography-mass spectroscopy (LC-MS)

Solar photocatalytic degradation of isoproturon over TiO2/H-MOR composite systems.

Science.gov (United States)

Sharma, Mangalampalli V Phanikrishna; Durgakumari, Valluri; Subrahmanyam, Machiraju

2008-12-30

The photocatalytic degradation and mineralization of isoproturon herbicide was investigated in aqueous solution containing TiO2 over H-mordenite (H-MOR) photocatalysts under solar light. The catalysts are characterized by X-ray diffraction (XRD), UV-Vis diffused reflectance spectra (UV-Vis DRS), Fourier transform-infra red spectra (FT-IR) and scanning electron microscopy (SEM) techniques. The effect of TiO2, H-MOR support and different wt% of TiO2 over the support on the photocatalytic degradation and influence of parameters such as TiO2 loading, catalyst amount, pH and initial concentration of isoproturon on degradation are evaluated. 15wt% TiO2/H-MOR composite is found to be optimum. The degradation reaction follows pseudo-first order kinetics and is discussed in terms of Langmuir-Hinshelwood (L-H) kinetic model. The extent of isoproturon mineralization studied with chemical oxygen demand (COD) and total organic carbon (TOC) measurements and approximately 80% mineralization occurred in 5h. A plausible mechanism is proposed based on the intermediates identified by liquid chromatography-mass spectroscopy (LC-MS).

Interaction of water, alkyl hydroperoxide, and allylic alcohol with a single-site homogeneous Ti-Si epoxidation catalyst: A spectroscopic and computational study.

Science.gov (United States)

Urakawa, Atsushi; Bürgi, Thomas; Skrabal, Peter; Bangerter, Felix; Baiker, Alfons

2005-02-17

Tetrakis(trimethylsiloxy)titanium (TTMST, Ti(OSiMe3)4) possesses an isolated Ti center and is a highly active homogeneous catalyst in epoxidation of various olefins. The structure of TTMST resembles that of the active sites in some heterogeneous Ti-Si epoxidation catalysts, especially silylated titania-silica mixed oxides. Water cleaves the Ti-O-Si bond and deactivates the catalyst. An alkyl hydroperoxide, TBHP (tert-butyl hydroperoxide), does not cleave the Ti-O-Si bond, but interacts via weak hydrogen-bonding as supported by NMR, DOSY, IR, and computational studies. ATR-IR spectroscopy combined with computational investigations shows that more than one, that is, up to four, TBHP can undergo hydrogen-bonding with TTMST, leading to the activation of the O-O bond of TBHP. The greater the number of TBHP molecules that form hydrogen bonds to TTMST, the more electrophilic the O-O bond becomes, and the more active the complex is for epoxidation. An allylic alcohol, 2-cyclohexen-1-ol, does not interact strongly with TTMST, but the interaction is prominent when it interacts with the TTMST-TBHP complex. On the basis of the experimental and theoretical findings, a hydrogen-bond-assisted epoxidation mechanism of TTMST is suggested.

The TApIR experiment. IR absorption spectra of liquid hydrogen isotopologues; Das TApIR Experiment IR-Absorptionsspektren fluessiger Wasserstoffisotopologe

Energy Technology Data Exchange (ETDEWEB)

Groessle, Robin

2015-11-27

The scope of the thesis is the infrared absorption spectroscopy of liquid hydrogen isotopologues with the tritium absorption infrared spectroscopy (TApIR) experiment at the tritium laboratory Karlsruhe (TLK). The calibration process from the sample preparation to the reference measurements are described. A further issue is the classical evaluation of FTIR absorption spectra and the extension using the rolling circle filter (RCF) including the effects on statistical and systematical errors. The impact of thermal and nuclear spin temperature on the IR absorption spectra is discussed. An empirical based modeling for the IR absorption spectra of liquid hydrogen isotopologues is performed.

Synthesis, Structural and Optical Properties of Co Doped TiO2 Nanocrystals by Sol-Gel Method

Directory of Open Access Journals (Sweden)

D.V. Sridevi

2017-06-01

Full Text Available A TiO2 nanoparticle doped with cobalt was synthesized by sol-gel technique employed at room temperature with appropriate reactants. In the present case, we used titanium tetra isoprotoxide (TTIP and 2–propanol as a common starting material and the obtained products were calcined at 450˚ C. From the Powder XRD data the particle size was calculated by Scherrer method. The FE-SEM analysis shows the morphology of cobalt doped TiO2 nanoparticles. The various functional groups of the samples were identified by Fourier transform spectroscopy (FT-IR. The UV-Vis-NIR spectra of cobalt doped TiO2 material shows two absorption peaks in the visible region related to d-d transitions of Co2+ in TiO2 lattice. Compared to un-doped TiO2 nanoparticles, the cobalt doped material show a red shift in the band gap.

Understanding the effect of flower extracts on the photoconducting properties of nanostructured TiO2.

Science.gov (United States)

Ansari, S G; Bhayana, Laitka; Umar, Ahmad; Al-Hajry, A; Al-Deyab, Salem S; Ansari, Z A

2012-10-01

Here we report an easy method to improve the optoelectronic properties of commercially available TiO2 nanopowder using extracts of various flowers viz. Calendula Orange (CO), Calendula Yellow (CY), Dahlia Violet (DV), Dahlia Yellow (DY), Rabbit flower (RF), Sweet Poppy (SP), Sweet Williams (SW) and their Mixed Extracts (ME). Various analysis techniques such as UV-Vis, FTIR, FESEM, XRD, and Raman spectroscopy were used to characterize for elemental, structural and morphological properties of the unmixed/mixed TiO2 nanopowder. TiO2 nanopowder was also calcined at 550 degrees C. Thick films of the these unmixed/mixed powder were printed, using conventional screen printing method, on fluorine doped tin oxide (FTO) substrate with organic binders and dried at 45 degrees C. The photoconducting properties are investigated as a function of wavelength from ultra-violet (UV) to infra-red (IR) region at a constant illumination intensity. Photocurrent gradually decreases when irradiated from UV to IR region. In case of unmixed and uncalcined TiO2, conductance decreased continuously whereas when extracts are added, a flat region of conductance is observed. The overall effect of extracts (colour pigments) is seen as an increase in the photoconductance. Highest photoconductance is observed in case of DY flower extract. Anthocyanins, present in flowers are known to have antioxidative properties and hence can contribute in photoconduction by reducing the surface adsorbed oxygen. This investigation indicates the potential use of flower extracts for dye sensitized solar cell (DSSC).

R{sub 4}Ir{sub 13}Ge{sub 9} (R=La, Ce, Pr, Nd, Sm) and RIr{sub 3}Ge{sub 2} (R=La, Ce, Pr, Nd): Crystal structures with nets of Ir atoms

Energy Technology Data Exchange (ETDEWEB)

Yarema, Maksym [Department of Inorganic Chemistry, Ivan Franko National University of Lviv, Kyryla i Mefodiya Str, 6, UA-79005 Lviv (Ukraine); Swiss Federal Laboratories for Materials Science and Technology (EMPA), Ueberlandstr. 129, CH-8600 Duebendorf (Switzerland); Zaremba, Oksana; Gladyshevskii, Roman [Department of Inorganic Chemistry, Ivan Franko National University of Lviv, Kyryla i Mefodiya Str, 6, UA-79005 Lviv (Ukraine); Hlukhyy, Viktor, E-mail: viktor.hlukhyy@lrz.tu-muenchen.de [Department Chemie, Technische Universitaet Muenchen, Lichtenbergstr. 4, D-85747 Garching (Germany); Faessler, Thomas F. [Department Chemie, Technische Universitaet Muenchen, Lichtenbergstr. 4, D-85747 Garching (Germany)

2012-12-15

The crystal structures of the new ternary compounds Sm{sub 4}Ir{sub 13}Ge{sub 9} and LaIr{sub 3}Ge{sub 2} were determined and refined on the basis of single-crystal X-ray diffraction data. They belong to the Ho{sub 4}Ir{sub 13}Ge{sub 9} (oP52, Pmmn) and CeCo{sub 3}B{sub 2} (hP5, P6/mmm) structure types, respectively. The formation of isotypic compounds R{sub 4}Ir{sub 13}Ge{sub 9} with R=La, Ce, Pr, Nd, and RIr{sub 3}Ge{sub 2} with R=Ce, Pr, Nd, was established by powder X-ray diffraction. The RIr{sub 3}Ge{sub 2} (R=La, Ce, Pr, Nd) compounds exist only in as-cast samples and decompose during annealing at 800 Degree-Sign C with the formation of R{sub 4}Ir{sub 13}Ge{sub 9}. The structure of Sm{sub 4}Ir{sub 13}Ge{sub 9} contains intersecting, slightly puckered nets of Ir atoms (4{sup 4})(4{sup 3}.6){sub 2}(4.6{sup 2}){sub 2} and (4{sup 4}){sub 2}(4{sup 3}.6){sub 4}(4.6{sup 2}){sub 2} that are perpendicular to [0 1 1] as well as to [0 -1 1] and [0 0 1]. The Ir atoms are surrounded by Ge atoms that form tetrahedra or square pyramids (where the layers intersect). The Sm and additional Ir atoms (in trigonal-planar coordination) are situated in channels along [1 0 0] (short translation vector). In the structure of LaIr{sub 3}Ge{sub 2} the Ir atoms form planar Kagome nets (3.6.3.6) perpendicular to [0 0 1]. These nets alternate along the short translation vector with layers of La and Ge atoms. - Graphical abstract: The crystal structures contain the nets of Ir atoms as main structural motif: R{sub 4}Ir{sub 13}Ge{sub 9} contains intersecting slightly puckered nets of Ir atoms, whereas in the structure of RIr{sub 3}Ge{sub 2} the Ir atoms form planar Kagome nets. Highlights: Black-Right-Pointing-Pointer The Ir-rich ternary germanides R{sub 4}Ir{sub 13}Ge{sub 9} (R=La, Ce, Pr, Nd, Sm) and RIr{sub 3}Ge{sub 2} (R=La, Ce, Pr, Nd) have been synthesized. Black-Right-Pointing-Pointer The RIr{sub 3}Ge{sub 2} compounds exist only in as-cast samples and decompose during annealing at 800

Perovskite solar cell with an efficient TiO₂ compact film.

Science.gov (United States)

Ke, Weijun; Fang, Guojia; Wang, Jing; Qin, Pingli; Tao, Hong; Lei, Hongwei; Liu, Qin; Dai, Xin; Zhao, Xingzhong

2014-09-24

A perovskite solar cell with a thin TiO2 compact film prepared by thermal oxidation of sputtered Ti film achieved a high efficiency of 15.07%. The thin TiO2 film prepared by thermal oxidation is very dense and inhibits the recombination process at the interface. The optimum thickness of the TiO2 compact film prepared by thermal oxidation is thinner than that prepared by spin-coating method. Also, the TiO2 compact film and the TiO2 porous film can be sintered at the same time. This one-step sintering process leads to a lower dark current density, a lower series resistance, and a higher recombination resistance than those of two-step sintering. Therefore, the perovskite solar cell with the TiO2 compact film prepared by thermal oxidation has a higher short-circuit current density and a higher fill factor.

Influence of TiCl4 post-treatment condition on TiO2 electrode for enhancement photovoltaic efficiency of dye-sensitized solar cells.

Science.gov (United States)

Eom, Tae Sung; Kim, Kyung Hwan; Bark, Chung Wung; Choi, Hyung Wook

2014-10-01

Titanium tetrachloride (TiCl4) treatment processed by chemical bath deposition is usually adopted as pre- and post-treatment for nanocrystalline titanium dioxide (TiO2) film deposition in the dye-sensitized solar cells (DSSCs) technology. TiCl4 post-treatment is a widely known method capable of improving the performance of dye-sensitized solar cells. In this work, the effect of TiCl4 post-treatment on the TiO2 electrode is proposed and compared to the untreated film. A TiO2 passivating layer was deposited on FTO glass by RF magnetron sputtering. The TiO2 sol prepared sol-gel method, nanoporous TiO2 upper layer was deposited by screen printing method on the passivating layer. TiCl4 post-treatment was deposited on the substrate by hydrolysis of TiCl4 aqueous solution. Crystalline structure was adjusted by various TiCl4 concentration and dipping time: 20 mM-150 mM and 30 min-120 min. The conversion efficiency was measured by solar simulator (100 mW/cm2). The dye-sensitized solar cell using TiCl4 post-treatment was measured the maximum conversion efficiency of 5.04% due to electron transport effectively. As a result, the DSSCs based on TiCl4 post-treatment showed better photovoltaic performance than cells made purely of TiO2 nanoparticles. The relative DSSCs devices are characterized in terms of short circuit current density, open circuit voltage, fill factor, conversion efficiency.

Optimization of photocatalytic treatment of dye solution on supported TiO2 nanoparticles by central composite design: Intermediates identification

International Nuclear Information System (INIS)

Khataee, A.R.; Fathinia, M.; Aber, S.; Zarei, M.

2010-01-01

Optimization of photocatalytic degradation of C.I. Basic Blue 3 (BB3) under UV light irradiation using TiO 2 nanoparticles in a rectangular photoreactor was studied. The investigated TiO 2 was Millennium PC-500 (crystallites mean size 5-10 nm) immobilized on non-woven paper. Central composite design was used for optimization of UV/TiO 2 process. Predicted values of decolorization efficiency were found to be in good agreement with experimental values (R 2 = 0.9686 and Adj-R 2 = 0.9411). Optimization results showed that maximum decolorization efficiency was achieved at the optimum conditions: initial dye concentration 10 mg/L, UV light intensity 47.2 W/m 2 , flow rate 100 mL/min and reaction time 120 min. Photocatalytic mineralization of BB3 was monitored by total organic carbon (TOC) decrease, and changes in UV-vis and FT-IR spectra. The photodegradation compounds were analyzed by UV-vis, FT-IR and GC-mass techniques. The degradation pathway of BB3 was proposed based on the identified compounds.

Tarptautinio turizmo raida ir vystymo prognozės Lietuvoje ir Lenkijoje

OpenAIRE

Veličkaitė, Dalia

2009-01-01

Išanalizuota ir įvertinta Lietuvos ir Lenkijos atvykstamojo turizmo raida 2000- 2007m., užsienio turistų srautai, apgyvendinimo paslaugų paklausa, turistų tikslai ir kelionių transporto pasirinkimas, turistų išlaidos ir šalių turizmo pajamos, iškeltos atvykstamojo turizmo problemos bei pateikti jų sprendimo siūlymai.paskutinėje darbo dalyje buvo atliktos 2008- 2015metų Lietuvos ir Lenkijos turizmo raidos prognozės. In the final master work Lithuanian and Poland arriving tourism development...

Visible light assisted photodecolorization of eosin-Y in aqueous solution using hesperidin modified TiO2 nanoparticles

Science.gov (United States)

Vignesh, K.; Suganthi, A.; Rajarajan, M.; Sakthivadivel, R.

2012-03-01

Hesperidin a flavanoid, modified TiO2 nanoparticles (Hes-TiO2) was synthesized to improve the visible light driven photocatalytic performance of TiO2. The synthesized nanoparticles were characterized by UV-visible diffuse reflectance spectroscopy (UV-vis-DRS), FT-IR, powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The photocatalytic activity of Hes-TiO2 was investigated based on the decolorization of eosin-Y under visible light irradiation. Hes-TiO2 showed high efficiency for the decolorization of eosin-Y. The influences of various reaction parameters like effect of pH, catalyst dosage and initial dye concentration on the photocatalytic efficiency were investigated. The adsorption of eosin-Y on Hes-TiO2 was found favorable by the Langmuir approach. The removal percentage of chemical oxygen demand (COD) was determined to evaluate the mineralization of eosin-Y during photodecolorization. Based on the intermediates obtained in the GC-MS spectroscopic technique, a probable degradation mechanism has been proposed.

Visible light assisted photodecolorization of eosin-Y in aqueous solution using hesperidin modified TiO2 nanoparticles

International Nuclear Information System (INIS)

Vignesh, K.; Suganthi, A.; Rajarajan, M.; Sakthivadivel, R.

2012-01-01

Hesperidin a flavanoid, modified TiO 2 nanoparticles (Hes-TiO 2 ) was synthesized to improve the visible light driven photocatalytic performance of TiO 2 . The synthesized nanoparticles were characterized by UV-visible diffuse reflectance spectroscopy (UV-vis-DRS), FT-IR, powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The photocatalytic activity of Hes-TiO 2 was investigated based on the decolorization of eosin-Y under visible light irradiation. Hes-TiO 2 showed high efficiency for the decolorization of eosin-Y. The influences of various reaction parameters like effect of pH, catalyst dosage and initial dye concentration on the photocatalytic efficiency were investigated. The adsorption of eosin-Y on Hes-TiO 2 was found favorable by the Langmuir approach. The removal percentage of chemical oxygen demand (COD) was determined to evaluate the mineralization of eosin-Y during photodecolorization. Based on the intermediates obtained in the GC-MS spectroscopic technique, a probable degradation mechanism has been proposed.

Butanol Dehydration over V₂O₅-TiO₂/MCM-41 Catalysts Prepared via Liquid Phase Atomic Layer Deposition.

Science.gov (United States)

Choi, Hyeonhee; Bae, Jung-Hyun; Kim, Do Heui; Park, Young-Kwon; Jeon, Jong-Ki

2013-04-29

MCM-41 was used as a support and, by using atomic layer deposition (ALD) in the liquid phase, a catalyst was prepared by consecutively loading titanium oxide and vanadium oxide to the support. This research analyzes the effect of the loading amount of vanadium oxide on the acidic characteristics and catalytic performance in the dehydration of butanol. The physical and chemical characteristics of the TiO₂-V₂O₅/MCM-41 catalysts were analyzed using XRF, BET, NH₃-TPD, XRD, Py-IR, and XPS. The dehydration reaction of butanol was performed in a fixed bed reactor. For the samples with vanadium oxide loaded to TiO₂/MCM-41 sample using the liquid phase ALD method, it was possible to increase the loading amount until the amount of vanadium oxide reached 12.1 wt %. It was confirmed that the structural properties of the mesoporous silica were retained well after titanium oxide and vanadium loading. The NH₃-TPD and Py-IR results indicated that weak acid sites were produced over the TiO₂/MCM-41 samples, which is attributed to the generation of Lewis acid sites. The highest activity of the V₂O₅(12.1)-TiO₂/MCM-41 catalyst in 2-butanol dehydration is ascribed to it having the highest number of Lewis acid sites, as well as the highest vanadium dispersion.

Combined two-photon excitation and d → f energy-transfer in Ir/lanthanide dyads with time-gated selection from a two-component emission spectrum.

Science.gov (United States)

Edkins, Robert M; Sykes, Daniel; Beeby, Andrew; Ward, Michael D

2012-10-14

In a pair of Ir/Eu and Ir/Tb dyads, two-photon excitation of the Ir-phenylpyridine chromophore at 780 nm is followed by partial d → f energy-transfer to give a combination of short-lived Ir-based (blue) and long-lived lanthanide-based (red or green) emission; these components can be selected separately by time-gated detection.

IR-IR Conformation Specific Spectroscopy of Na+(Glucose) Adducts

Science.gov (United States)

Voss, Jonathan M.; Kregel, Steven J.; Fischer, Kaitlyn C.; Garand, Etienne

2018-01-01

We report an IR-IR double resonance study of the structural landscape present in the Na+(glucose) complex. Our experimental approach involves minimal modifications to a typical IR predissociation setup, and can be carried out via ion-dip or isomer-burning methods, providing additional flexibility to suit different experimental needs. In the current study, the single-laser IR predissociation spectrum of Na+(glucose), which clearly indicates contributions from multiple structures, was experimentally disentangled to reveal the presence of three α-conformers and five β-conformers. Comparisons with calculations show that these eight conformations correspond to the lowest energy gas-phase structures with distinctive Na+ coordination. [Figure not available: see fulltext.

PKCδ-mediated IRS-1 Ser24 phosphorylation negatively regulates IRS-1 function

International Nuclear Information System (INIS)

Greene, Michael W.; Ruhoff, Mary S.; Roth, Richard A.; Kim, Jeong-a; Quon, Michael J.; Krause, Jean A.

2006-01-01

The IRS-1 PH and PTB domains are essential for insulin-stimulated IRS-1 Tyr phosphorylation and insulin signaling, while Ser/Thr phosphorylation of IRS-1 disrupts these signaling events. To investigate consensus PKC phosphorylation sites in the PH-PTB domains of human IRS-1, we changed Ser24, Ser58, and Thr191 to Ala (3A) or Glu (3E), to block or mimic phosphorylation, respectively. The 3A mutant abrogated the inhibitory effect of PKCδ on insulin-stimulated IRS-1 Tyr phosphorylation, while reductions in insulin-stimulated IRS-1 Tyr phosphorylation, cellular proliferation, and Akt activation were observed with the 3E mutant. When single Glu mutants were tested, the Ser24 to Glu mutant had the greatest inhibitory effect on insulin-stimulated IRS-1 Tyr phosphorylation. PKCδ-mediated IRS-1 Ser24 phosphorylation was confirmed in cells with PKCδ catalytic domain mutants and by an RNAi method. Mechanistic studies revealed that IRS-1 with Ala and Glu point mutations at Ser24 impaired phosphatidylinositol-4,5-bisphosphate binding. In summary, our data are consistent with the hypothesis that Ser24 is a negative regulatory phosphorylation site in IRS-1

Nanographite-TiO_2 photoanode for dye sensitized solar cells

International Nuclear Information System (INIS)

Sharma, S. S.; Sharma, Khushboo; Sharma, Vinay

2016-01-01

Nanographite-TiO_2 (NG-TiO_2) composite was successfully synthesized by the hydrothermal method and its performance as the photoanode for dye-sensitized solar cells (DSSCs) was investigated. Environmental Scanning electron microscope (E-SEM) micrographs show the uniform distribution of TiO_2 nanoflowers deposited over nanographite sheets. The average performance characteristics of the assembled cell in terms of short-ciruit current density (J_S_C), open circuit voltage (V_O_C), fill factor (FF) and photoelectric conversion efficiency (η) were measured.

The Influence of Cr3+ on TiO2 Crystal Growth and Photoactivity Properties

Science.gov (United States)

Wahyuningsih, S.; Hidayatika, W. N.; Sari, P. L.; Sari, P. P.; Hidayat, R.; Munawaroh, H.; Ramelan, A. H.

2018-03-01

The photocatalyst technology is an integrated combination of photochemical processes and catalysis in order to carry out a chemical transformation reaction. One of the semiconductor materials that have good photocatalytic activity is TiO2 anatase. This study aim to determine the effect of the Cr3+ addition on the growth of TiO2 rutile crystal and the increasing of TiO2 photoactivity. Diffractogram X-Ray of the samples showed that the synthesized TiO2 at 400 °C has been produced 100% TiO2 anatase. Synthesis of TiO2 doped Cr3+ composite was using wet impregnation method. The TiO2 doped Cr3+ composites have beed grown by annealed at a temperature of 300, 400, 500, 600 and 700 °C, respectively Annealing process have capabled to gain to the TiO2 doped Cr3+ nanocomposite. The result product annealed at 500 °C only appear anatase phase due to the Cr3+ addition influence that was able to suppress the growth of rutile. Identification of TiO2 doped Cr3+ composite using Fourier Transform Infra-Red (FT-IR) showed O-Cr vibration at 2283.72 cm-1. The TiO2 doped Cr3+ photoactivity was studied to degrade Rhodamin B. The best result on photodegradation of Rhodamin B was performed by using TiO2 doped Cr3+ composite which was annealed at 700 °C i.e. 74.71%.

The Effects of Anchor Groups on (1) TiO2-Catalyzed Photooxidation and (2) Linker-Assisted Assembly on TiO2

Science.gov (United States)

Anderson, Ian Mark

Quantum dot-sensitized solar cells (QDSSCs) are a popular target for research due to their potential for highly efficient, easily tuned absorption. Typically, light is absorbed by quantum dots attached to a semiconductor substrate, such as TiO2, via bifunctional linker molecules. This research aims to create a patterned monolayer of linker molecules on a TiO2 film, which would in turn allow the attachment of a patterned layer of quantum dots. One method for the creation of a patterned monolayer is the functionalization of a TiO2 film with a linker molecule, followed by illumination with a laser at 355 nm. This initiates a TiO 2-catalyzed oxidation reaction, causing loss of surface coverage. A second linker molecule can then be adsorbed onto the TiO2 surface in the illuminated area. Towards that end, the behaviors of carboxylic and phosphonic acids adsorbed on TiO2 have been studied. TiO2 films were functionalized by immersion in solutions a single adsorbate and surface coverage was determined by IR spectroscopy. It is shown that phosphonic acids attain higher surface coverage than carboxylic acids, and will displace them from TiO2 when in a polar solvent. Alkyl chain lengths, which can influence stabilities of monolayers, are shown not to have an effect on this relationship. Equilibrium binding data for the adsorption of n-hexadecanoic acid to TiO2 from a THF solution are presented. It is shown that solvent polarity can affect monolayer stability; carboxylates and phosphonates undergo more desorption into polar solvents than nonpolar. Through illumination, it was possible to remove nearly all adsorbed linkers from TiO2. However, the illuminated areas were found not to be receptive to attachment by a second adsorbate. A possible reason for this behavior is presented. I also report on the synthesis and characterization of a straight-chain, thiol-terminated phosphonic acid. Initial experiments involving monolayer formation and quantum dot attachment are presented

Efficient in situ synthetic routes of polyaniline/poly(vinyl alcohol)/TiO2 nanocomposites using gamma irradiation

Science.gov (United States)

Afify, T. A.; Ghazy, O. A.; Saleh, H. H.; Ali, Z. I.

2018-02-01

Gamma radiation was used to prepare nanocomposites based on polyaniline/titanium dioxide (PANI/TiO2) or polyaniline/poly (vinyl alcohol)/titanium dioxide (PANI/PVA/TiO2). It was found that PANI/TiO2 in the form of nanocomposite as shown by the UV/vis spectroscopy. This was through the appearance and shift of two absorption peaks at 340 and 598 nm. The SEM micrographs of the PANI/TiO2 nanocomposites showed a fibrous morphology before the treatment with HCl. The TiO2 nanoparticles are clearly seen to be precipitated on the PANI fibers and the morphology changed towards the sheets shape with highly distribution on PANI surface. The transmission electron microscopy (TEM) image confirms the fibrous shape of the PANI and spherical shape of TiO2 nanoparticles. The XRD study showed a several diffraction patterns of TiO2 nanoparticles confirming the PANI/TiO2 and PANI/PVA/TiO2 nanocomposites. The FT-IR analysis indicated that there is an interfacial interaction existed between the PANI and its inorganic counterpart of TiO2 nanoparticles. The dielectric constant of the PANI/PVA showed the lowest values and was increased by either doping with TiO2 or increasing irradiation dose.

Uzņēmuma tēla ietekme uz zīmola popularitāti, pamatojoties uz "Nike Inc." kompānijas piemēru.

OpenAIRE

Kadauova, Aļona

2015-01-01

Šī diplomdarba tēmas aktualitāti nosaka tas, ka pētījumi un praktiskā pieredze parāda, ka mūsdienās veiksmīgai kompānijai ir jābūt zīmola stratēģijai, kas ir virzīta uz patērētāja uzticības veidošanu. Tā kā zīmola „vērtību” nosaka patērētāja gatavība iegādāties preci par daudz augstāku cenu, ja tirgū ir citu prečzīmju analoģiskās preces. Šī diplomdarba mērķis ir uzņēmuma tēla ietekmes uz zīmola popularitāti būtības atklāšana, izanalizējot teoriju. Kā arī izpētīt kompānijas "Nike Inc." zīmo...

Surface chemical state of Ti powders and its alloys: Effect of storage conditions and alloy composition

Energy Technology Data Exchange (ETDEWEB)

Hryha, Eduard, E-mail: hryha@chalmers.se [Department of Materials and Manufacturing Technology, Chalmers University of Technology, Rännvägen 2A, SE - 412 96 Gothenburg (Sweden); Shvab, Ruslan [Department of Materials and Manufacturing Technology, Chalmers University of Technology, Rännvägen 2A, SE - 412 96 Gothenburg (Sweden); Bram, Martin; Bitzer, Martin [Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research, Materials Synthesis and Processing (IEK-1), D-52425 Jülich (Germany); Nyborg, Lars [Department of Materials and Manufacturing Technology, Chalmers University of Technology, Rännvägen 2A, SE - 412 96 Gothenburg (Sweden)

2016-12-01

Highlights: • Powder particles of Ti, NiTi and Ti6Al4V are covered by homogeneous Ti-oxide layer. • Thickness of the Ti-oxide layer is in the range of 2.9 to 4.2 nm in as-atomized state. • Exposure to the air results in immediate oxide thickness increase of up to 30%. • Oxide thickness increase of only 15% during storage for 8 years. • High passivation of the Ti, NiTi and Ti6Al4V powder surface by Ti-oxide layer. - Abstract: High affinity of titanium to oxygen in combination with the high surface area of the powder results in tremendous powder reactivity and almost inevitable presence of passivation oxide film on the powder surface. Oxide film is formed during the short exposure of the powder to the environment at even a trace amount of oxygen. Hence, surface state of the powder determines its usefulness for powder metallurgy processing. Present study is focused on the evaluation of the surface oxide state of the Ti, NiTi and Ti6Al4V powders in as-atomized state and after storage under air or Ar for up to eight years. Powder surface oxide state was studied by X-ray photoelectron spectroscopy (XPS) and high resolution scanning electron microscopy (HR SEM). Results indicate that powder in as-atomized state is covered by homogeneous Ti-oxide layer with the thickness of ∼2.9 nm for Ti, ∼3.2 nm and ∼4.2 nm in case of Ti6Al4V and NiTi powders, respectively. Exposure to the air results in oxide growth of about 30% in case of Ti and only about 10% in case of NiTi and Ti6Al4V. After the storage under the dry air for two years oxide growth of only about 3-4% was detected in case of both, Ti and NiTi powders. NiTi powder, stored under the dry air for eight years, indicates oxide thickness of about 5.3 nm, which is about 30% thicker in comparison with the as-atomized powder. Oxide thickness increase of only ∼15% during the storage for eight years in comparison with the powder, shortly exposed to the air after manufacturing, was detected. Results indicate a

Status and Plans for the SPS to LHC Beam Transfer Lines TI 2 and TI 8

CERN Document Server

Goddard, B; Risselada, Thys

2004-01-01

Beam transfer from the CERN Super Proton Synchrotron (SPS) to the Large Hadron Collider (LHC) will be done through the two transfer lines TI 2 and TI 8, presently under construction, with a combined length of about 5.6 km. The final layout, optics design and correction scheme for these lines will be presented. The requirement of simultaneously matching their geometry and optics with that of the LHC will be treated, including the methodology for alignment of the elements along the line and a proposed solution in the final matching section. After the commissioning of the short transfer line TT40 just upstream of TI 8 in 2003, beam tests of the whole of TI 8 are scheduled for autumn 2004, with the aim to validate many of the new features and mechanisms involved in the future control and operation of these lines. The status of the installation will be described, comprising the progress with infrastructure, services and line elements. An outlook will be given for the work remaining until 2007.

Solar photocatalytic degradation of isoproturon over TiO{sub 2}/H-MOR composite systems

Energy Technology Data Exchange (ETDEWEB)

Sharma, Mangalampalli V. Phanikrishna; Durgakumari, Valluri [Inorganic and Physical Chemistry Division, Indian Institute of Chemical Technology, Hyderabad 500607 (India); Subrahmanyam, Machiraju [Inorganic and Physical Chemistry Division, Indian Institute of Chemical Technology, Hyderabad 500607 (India)], E-mail: subrahmanyam@iict.res.in

2008-12-30

The photocatalytic degradation and mineralization of isoproturon herbicide was investigated in aqueous solution containing TiO{sub 2} over H-mordenite (H-MOR) photocatalysts under solar light. The catalysts are characterized by X-ray diffraction (XRD), UV-Vis diffused reflectance spectra (UV-Vis DRS), Fourier transform-infra red spectra (FT-IR) and scanning electron microscopy (SEM) techniques. The effect of TiO{sub 2}, H-MOR support and different wt% of TiO{sub 2} over the support on the photocatalytic degradation and influence of parameters such as TiO{sub 2} loading, catalyst amount, pH and initial concentration of isoproturon on degradation are evaluated. 15 wt% TiO{sub 2}/H-MOR composite is found to be optimum. The degradation reaction follows pseudo-first order kinetics and is discussed in terms of Langmuir-Hinshelwood (L-H) kinetic model. The extent of isoproturon mineralization studied with chemical oxygen demand (COD) and total organic carbon (TOC) measurements and {approx}80% mineralization occurred in 5 h. A plausible mechanism is proposed based on the intermediates identified by liquid chromatography-mass spectroscopy (LC-MS)

SHORT COMMUNICATION CONVENIENT AND MILD SYNTHESIS ...

African Journals Online (AJOL)

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*Corresponding author. E-mail: naeimi@kashanu.ac.ir. SHORT COMMUNICATION. CONVENIENT AND MILD SYNTHESIS AND CHARACTERISATION OF. SOME NEW SCHIFF BASES. Hossein Naeimi* and Zahra Sadat Nazifi. Department of Organic Chemistry, Faculty of Chemistry, University of Kashan,. Kashan, 87317 ...

Synthesis of SiCN@TiO2 core-shell ceramic microspheres via PDCs method

Science.gov (United States)

Liu, Hongli; Wei, Ning; Li, Jing; Zhang, Haiyuan; Chu, Peng

2018-02-01

A facile and effective polymer-derived ceramics (PDCs) emulsification-crosslinking-pyrolysis method was developed to fabricate SiCN@TiO2 core-shell ceramic microspheres with polyvinylsilazane (PVSZ) and tetrabutyl titanate (TBT) as precursors. The TBT: PVSZ mass ratios, emulsifier concentrations and the pyrolysis temperature were examined as control parameters to tune the size and morphology of microspheres. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) confirmed the synthesized SiCN@TiO2 microspheres to be comprised of SiCN core coated with TiO2 crystals, with an average size of 0.88 μm when pyrolyzed at 1400 °C. The analysis of Fourier transform infrared spectroscopy (FT-IR), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) ensured that SiCN@TiO2 core-shell ceramic microspheres composed of rutile TiO2, β-SiC and Si3N4 crystalline phases, The thermal properties were characterized by thermogravimetric analysis (TGA). The obtained SiCN@TiO2 core-shell ceramic microspheres were the promising candidate of the infrared opacifier in silica aerogels and this technique can be extended to other preceramic polymers.

Effect of Core-Shell Ag@TiO2 Volume Ratio on Characteristics of TiO2-Based DSSCs

Directory of Open Access Journals (Sweden)

Ho Chang

2014-01-01

Full Text Available This paper aims to develop photoanode material required by dye-sensitized solar cells. The material prepared is in the form of Ag@TiO2 core-shell-type nanocomposites. This material is used to replace the titanium oxide powder commonly used in general DSSCs. The prepared Ag@TiO2 core-shell-type nanocomposites are mixed with Degussa P25 TiO2 in different proportions. Triton X-100 is added and polyethylene glycol (PEG at 20 wt% is used as a polymer additive. This study tests the particle size and material properties of Ag@TiO2 core-shell-type nanocomposites and measures the photoelectric conversion efficiency and IPCE of DSSCs. Experimental results show that the DSSC prepared by Ag@TiO2 core-shell-type nanocomposites can achieve a photoelectric conversion efficiency of 3.67%. When Ag@TiO2 core-shell-type nanocomposites are mixed with P25 nanoparticles in specific proportions, and when the thickness of the photoelectrode thin film is 28 μm, the photoelectric conversion efficiency can reach 6.06%, with a fill factor of 0.52, open-circuit voltage of 0.64V, and short-circuit density of 18.22 mAcm−2. Compared to the DSSC prepared by P25 TiO2 only, the photoelectric conversion efficiency can be raised by 38% under the proposed approach.

Visible-light photocatalytic performances of TiO2 nanoparticles modified by trace derivatives of PVA

Directory of Open Access Journals (Sweden)

Le SHI

2016-10-01

Full Text Available In order to study the visible-light photocatalytic activity and catalysis stability of nanocomposites, a TiO2-based visible-light photocatalyst is prepared by surface-modification of TiO2 nanoparticles using trace conjugated derivatives from polyvinyl alcohol (DPVA via a facile method. The obtained DPVA/TiO2 nanocomposites are characterized by X-ray diffraction (XRD, Fourier transform infrared Spectra (FT-IR, scanning electron microscopy (SEM, UV-vis diffuse reflection spectroscopy (DRS, and X-ray photoelectron spectroscopy (XPS. With Rhodamine B (RhB as a model pollutant, the visible-light photocatalytic activity and stability of DPVA/TiO2 nanocomposites are investigated by evaluating the RhB decomposition under visible light irradiation. The results reveal that the trace conjugated polymers on the TiO2 surface doesn’t change the crystalline and crystal size of TiO2 nanoparticles, but significantly enhances their visible-light absorbance and visible-light photocatalytic activity. The nanocomposite with the PVA and TiO2 mass ratio of 1∶200 exhibits the highest visible-light photocatalytic activity. The investigated nanocomposites exhibit well visible-light photoctatalytic stability. The photogenerated holes are thought as the main active species for the RhB photodegradation in the presence of the DPVA/TiO2 nanocomposites.

Preparation of TiO2 thin films from autoclaved sol containing needle-like anatase crystals

International Nuclear Information System (INIS)

Ge Lei; Xu Mingxia; Fang Haibo; Sun Ming

2006-01-01

A new inorganic sol-gel method was introduced in this paper to prepare TiO 2 thin films. The autoclaved sol with needle-like anatase crystals was synthesized using titanyl sulfate (TiOSO 4 ) and peroxide (H 2 O 2 ) as starting materials. The transparent anatase TiO 2 thin films were prepared on glass slides from the autoclaved sol by sol-gel dip-coating method. A wide range of techniques such as Fourier transform infrared transmission spectra (FT-IR), X-ray diffraction (XRD), thermogravimetry-differential thermal analysis (TG-DTA), scanning electron microscopes, X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible spectrum were applied to characterize the autoclaved sol and TiO 2 thin films. The results indicate that the autoclaved sol is flavescent, semitransparent and stable at room temperature. The anatase crystals of TiO 2 films connect together to form net-like structure after calcined and the films become uniform with increasing heating temperature. The surface of the TiO 2 films contain not only Ti and O elements, but also a small amount of N and Na elements diffused from substrates during heat treatment. The TiO 2 films are transparent and their maximal light transmittances exceed 80% under visible light region

Magnéli phases Ti{sub 4}O{sub 7} and Ti{sub 8}O{sub 15} and their carbon nanocomposites via the thermal decomposition-precursor route

Energy Technology Data Exchange (ETDEWEB)

Conze, S., E-mail: susan.conze@ikts.fraunhofer.de [Fraunhofer Institute for Ceramic Technologies and Systems IKTS, Winterbergstr. 28, 01277 Dresden (Germany); Veremchuk, I. [Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden (Germany); Reibold, M. [Technical University of Dresden, Zum Triebenberg 50, 01328 Dresden (Zaschendorf) (Germany); Matthey, B.; Michaelis, A. [Fraunhofer Institute for Ceramic Technologies and Systems IKTS, Winterbergstr. 28, 01277 Dresden (Germany); Grin, Yu. [Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden (Germany); Kinski, I. [Fraunhofer Institute for Ceramic Technologies and Systems IKTS, Winterbergstr. 28, 01277 Dresden (Germany)

2015-09-15

A new synthetic approach for producing nano-powders of the Magnéli phases Ti{sub 4}O{sub 7}, Ti{sub 8}O{sub 15} and their carbon nanocomposites by thermal decomposition-precursor route is proposed. The formation mechanism of the single-phase carbon nanocomposites (Ti{sub 4}O{sub 7}/C and Ti{sub 8}O{sub 15}/C) from metal–organic precursors is studied using FT-IR, elemental analysis, TG, STA-MS and others. The synthesis parameters and conditions were optimized to prepare the target oxides with the desired microstructure and physical properties. The electrical and transport properties of Ti{sub 4}O{sub 7}/C and Ti{sub 8}O{sub 15}/C are investigated. These nano-materials are n-type semiconductors with relatively low thermal conductivity in contrast to the bulk species. The nanostructured carbon nanocomposites of Magnéli phases achieve a low thermal conductivity close to 1 W/m K at RT. The maximum ZT{sub 570} {sub °C} values are 0.04 for Ti{sub 4}O{sub 7}/C powder nanocomposite and 0.01 for Ti{sub 8}O{sub 15}/C bulk nanocomposite. - Graphical abstract: From the precursor to the produced titanium oxide pellet and its microstructure (SEM, TEM micrographs) as well as results of phase and thermoelectric analyses. - Highlights: • Magnéli phases Ti{sub 4}O{sub 7}/Ti{sub 8}O{sub 15} via thermal decomposition-precursor route is proposed. • The formation mechanism of the nanocomposites Ti{sub 4}O{sub 7}/C and Ti{sub 8}O{sub 15}/C are investigated. • Microstructure of Ti{sub 4}O{sub 7}/C and Ti{sub 8}O{sub 15}/C are examined. • The electrical and transport properties of Ti{sub 4}O{sub 7}/C and Ti{sub 8}O{sub 15}/C are investigated. • The maximum figure of mertit ZT{sub 570} {sub °C} of Ti{sub 4}O{sub 7}/C and Ti{sub 8}O{sub 15}/C are 0.01 and 0.04.

A facile approach to fabrication of novel CeO{sub 2}-TiO{sub 2} core-shell nanocomposite leads to excellent UV-shielding ability and lower catalytic activity

Energy Technology Data Exchange (ETDEWEB)

Bahadur, Newaz Mohammed, E-mail: nmbahadur@yahoo.com [Utsunomiya University, Laboratory of Powder Technology, Graduate School of Engineering, Venture Business Laboratry (Japan); Kurayama, Fumio [Utsunomiya University, Center for Optical Research and Education (Japan); Furusawa, Takeshi; Sato, Masahide [Utsunomiya University, Department of Advanced Interdisciplinary Sciences (Japan); Siddiquey, Iqbal Ahmed [Utsunomiya University, Laboratory of Powder Technology, Graduate School of Engineering, Venture Business Laboratry (Japan); Hossain, Md. Mufazzal [University of Dhaka, Department of Chemistry (Bangladesh); Suzuki, Noboru [Utsunomiya University, Laboratory of Powder Technology, Graduate School of Engineering, Venture Business Laboratry (Japan)

2013-01-15

This study reports the development of a fast and facile route for the synthesis of novel CeO{sub 2}-TiO{sub 2} core-shell nanocomposite particles using microwave (MW) irradiation of the mixture of commercial CeO{sub 2}, titanium-tetra-n-butoxide (TBOT) and aqueous ammonia. Solutions of TBOT in ethanol and ammonia were mixed with dispersed CeO{sub 2} nanoparticles in ethanol, and the mixture was rapidly MW irradiated at 70 Degree-Sign C for 2 min. The resulting nanocomposite particles were characterized in terms of phase, shell thickness, composition, surface charge, morphology, and chemical state of the elements by XRD, TEM, XPS, SEM, Zeta potential analyzer, XRF, and FT-IR. Conventional methods of the synthesis of CeO{sub 2}-TiO{sub 2} nanocomposite require a long time, and TiO{sub 2} is rarely found as a coated material. In contrast, the MW method was able to synthesize CeO{sub 2}-TiO{sub 2} core-shell nanocompsite particles within a very short time. CeO{sub 2}-TiO{sub 2} nanocomposite particles were fairly unaggregated with an average titania layer thickness of 2-5 nm. The obtained nanocomposites retained the crystalline cubic phase of CeO{sub 2}, and the phase of coated TiO{sub 2} was amorphous. The catalytic activities of uncoated and TiO{sub 2}-coated CeO{sub 2} nanoparticles for the oxidation of organic compounds were evaluated by the degradation study of methylene blue in air atmosphere at 403 K. The enhanced UV-shielding ability and visible transparency of the nanocomposite obtained by UV visible spectroscopic measurements suggested that the core-shell material has novel characteristics for using as a sunscreen material.

Nanomechanical properties of TiCN and TiCN/Ti coatings on Ti prepared by Filtered Arc Deposition

International Nuclear Information System (INIS)

Sun, Yong; Lu, Cheng; Yu, Hailiang; Kiet Tieu, A.; Su, Lihong; Zhao, Yue; Zhu, Hongtao; Kong, Charlie

2015-01-01

Monolayer TiCN and multilayer TiCN/Ti coatings were deposited on the surface of Ti using the Filtered Arc Deposition System (FADS). Nanoindentation tests were performed on both coatings. The multilayer TiCN/Ti coating exhibited better ductility than the monolayer TiCN coating. The lattice constants of the coatings were characterized by X-ray diffraction. Transmission Electron Microscopy (TEM) was used to investigate the fracture behavior of the coatings. Inter-columnar, inclined and lateral cracks were found to be the dominant crack modes in the monolayer TiCN coatings while small bending crack and radial crack were the dominant crack modes in the multilayer TiCN/Ti coatings. The Finite Element Method (FEM) was used to simulate the indentation process. It was found that the Ti interlayer in the multilayer TiCN/Ti coating could efficiently suppress the fracture, which is responsible for the improved ductility of the multilayer TiCN/Ti coating

Short-Range Vital Signs Sensing Based on EEMD and CWT Using IR-UWB Radar

Directory of Open Access Journals (Sweden)

Xikun Hu

2016-11-01

Full Text Available The radar sensor described realizes healthcare monitoring capable of detecting subject chest-wall movement caused by cardiopulmonary activities and wirelessly estimating the respiration and heartbeat rates of the subject without attaching any devices to the body. Conventional single-tone Doppler radar can only capture Doppler signatures because of a lack of bandwidth information with noncontact sensors. In contrast, we take full advantage of impulse radio ultra-wideband (IR-UWB radar to achieve low power consumption and convenient portability, with a flexible detection range and desirable accuracy. A noise reduction method based on improved ensemble empirical mode decomposition (EEMD and a vital sign separation method based on the continuous-wavelet transform (CWT are proposed jointly to improve the signal-to-noise ratio (SNR in order to acquire accurate respiration and heartbeat rates. Experimental results illustrate that respiration and heartbeat signals can be extracted accurately under different conditions. This noncontact healthcare sensor system proves the commercial feasibility and considerable accessibility of using compact IR-UWB radar for emerging biomedical applications.

Precipitation evolution in a Ti-free and Ti-containing stainless maraging steel

International Nuclear Information System (INIS)

Schober, M.; Schnitzer, R.; Leitner, H.

2009-01-01

Stainless maraging steels have a Cr content higher than 12 wt% and show a excellent combination of high strength and ductility, which make them attractive for use in machinery fields and aircraft applications. The massive increase of strength during ageing treatment of maraging steels is related to a precipitation sequence of various nm-scaled intermetallic phases. The peak hardness especially in Ti-containing maraging steels can be reached after short-time ageing at temperatures around 500 o C. However, precipitation reactions in different stainless maraging steels are not fully understood, especially the evolution from clustering over growing to coarsening. In the present work a commercial maraging steel and a Ti-containing model alloy are investigated and compared to each other. The steels were isothermally heat treated at 525 o C for a range of times. Special emphasis was laid on the correlation of hardness to the formation and presence of different kinds of precipitates. The isothermal aged samples were investigated by using two advanced three-dimensional energy compensated atom probes (LEAP TM and 3DAP TM ) both in voltage mode and in laser mode. The atom probe data were correlated to standard hardness measurements. The results show that the partial substitution of Al by Ti results in a different precipitation behaviour. While the Ti-free maraging steel exhibit only one type of precipitate, the Ti-containing grade shows a change in the type of precipitates during ageing. However, this change leads to an accelerated coarsening and thus to a faster drop in hardness.

Precipitation evolution in a Ti-free and Ti-containing stainless maraging steel.

Science.gov (United States)

Schober, M; Schnitzer, R; Leitner, H

2009-04-01

Stainless maraging steels have a Cr content higher than 12wt% and show a excellent combination of high strength and ductility, which make them attractive for use in machinery fields and aircraft applications. The massive increase of strength during ageing treatment of maraging steels is related to a precipitation sequence of various nm-scaled intermetallic phases. The peak hardness especially in Ti-containing maraging steels can be reached after short-time ageing at temperatures around 500 degrees C. However, precipitation reactions in different stainless maraging steels are not fully understood, especially the evolution from clustering over growing to coarsening. In the present work a commercial maraging steel and a Ti-containing model alloy are investigated and compared to each other. The steels were isothermally heat treated at 525 degrees C for a range of times. Special emphasis was laid on the correlation of hardness to the formation and presence of different kinds of precipitates. The isothermal aged samples were investigated by using two advanced three-dimensional energy compensated atom probes (LEAP and 3DAP) both in voltage mode and in laser mode. The atom probe data were correlated to standard hardness measurements. The results show that the partial substitution of Al by Ti results in a different precipitation behaviour. While the Ti-free maraging steel exhibit only one type of precipitate, the Ti-containing grade shows a change in the type of precipitates during ageing. However, this change leads to an accelerated coarsening and thus to a faster drop in hardness.

Fabrication of Tiron-TiO{sub 2} charge-transfer complex with excellent visible-light photocatalytic performance

Energy Technology Data Exchange (ETDEWEB)

Yao, Binghua, E-mail: bhyao@xaut.edu.cn [Department of Applied Chemistry, Xi' an University of Technology, Xi' an 710048 (China); The Key Laboratory of Northwest Water Resources and Environmental Ecology of Ministry of Education, Xi' an University of Technology, Xi' an 710048 (China); Peng, Chao; Lu, Pan; He, Yangqing [Department of Applied Chemistry, Xi' an University of Technology, Xi' an 710048 (China); Zhang, Wen, E-mail: wenzhang@uark.edu [Department of Civil Engineering, University of Arkansas, Fayetteville 72701 (United States); Zhang, Qinku [Department of Applied Chemistry, Xi' an University of Technology, Xi' an 710048 (China); The Key Laboratory of Northwest Water Resources and Environmental Ecology of Ministry of Education, Xi' an University of Technology, Xi' an 710048 (China)

2016-12-01

A new charge-transfer(CT) complex (Tiron-TiO{sub 2}) was prepared via the 1,2-dihydroxy-3,5-benzenedisulfonic acid disodium salt (Tiron) as chelate sensitizer. The phase structures and morphologies were measured by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results demonstrated that the as-prepared Tiron-TiO{sub 2} is of anatase microspheres with size range between 300 and 350 nm. The analysis of FT-IR and XPS revealed that the binding structure of the Tiron-TiO{sub 2} CT complex is of the characteristic of bidentate binuclear binding-bridging. UV–vis analysis showed that the formation of CT complex on the surface of TiO{sub 2} through Tiron significantly extends the photoresponse of Tiron-TiO{sub 2} nanoparticles to visible light range (400–600 nm). Compared with unmodified TiO{sub 2}, Tiron-modified TiO{sub 2}(Tiron-TiO{sub 2}) exhibited excellent photocatalytic activity for the photocatalytic degradation of methylene blue(MB) and three kind of antibiotics under visible light irradiation (λ > 400 nm). - Highlights: • The Tiron-TiO{sub 2} charge transfer complex was synthesized. • The incorporation of Tiron with TiO{sub 2} extended TiO{sub 2} response to visible light region. • Tiron-TiO{sub 2} exhibited significant photocatalytic degradation for antibiotics. • Tiron-TiO{sub 2} showed the long-term stability and reusability.

Dielectric properties of Mn doped SrTiO.sub.3./sub..

Czech Academy of Sciences Publication Activity Database

Savinov, Maxim; Trepakov, Vladimír; Syrnikov, P. P.; Železný, Vladimír; Pokorný, Jan; Deyneka, Alexander; Jastrabík, Lubomír; Galinetto, P.

2008-01-01

Roč. 20, - (2008), 095221/1-095221/6 ISSN 0953-8984 R&D Projects: GA AV ČR KAN301370701; GA AV ČR 1QS100100563; GA MŠk(CZ) 1M06002 Institutional research plan: CEZ:AV0Z10100522; CEZ:AV0Z10100521 Keywords : dielectric permittivity * IR reflectivity * SrTiO3:Mn Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.900, year: 2008

Effect of sulfate ions on the crystallization and photocatalytic activity of TiO2/diatomite composite photocatalyst

Science.gov (United States)

Zhang, Jinjun; Wang, Xiaoyan; Wang, Jimei; Wang, Jing; Ji, Zhijiang

2016-01-01

TiO2 nanoparticles were immobilized on diatomite by hydrolysis-deposition method using titanium tetrachloride as precursor. The effect of sulfate ions on the crystallization and photocatalytic activity of TiO2/diatomite composite photocatalyst was characterized by TG-DSC, XRD, BET surface area, SEM, FT-IR spectroscopy, XPS and UV-vis diffuse reflectance spectra. The results indicate that addition of a small amount of sulfate ions promotes the formation of anatase phase and inhibits the transformation from anatase to rutile. On the other hand, sulfate ions immobilized on the surface of TiO2/diatomite have strong affinity for electrons, capturing the photo-generated electrons, which hinders the recombination of electrons and holes.

Adjustment of Conduction Band Edge of Compact TiO2 Layer in Perovskite Solar Cells Through TiCl4 Treatment.

Science.gov (United States)

Murakami, Takurou N; Miyadera, Tetsuhiko; Funaki, Takashi; Cojocaru, Ludmila; Kazaoui, Said; Chikamatsu, Masayuki; Segawa, Hiroshi

2017-10-25

Perovskite solar cells (PSCs) without a mesoporous TiO 2 layer, that is, planar-type PSCs exhibit poorer cell performance as compared to PSCs with a porous TiO 2 layer, owing to inefficient electron transfer from the perovskite layer to the compact TiO 2 layer in the former case. The matching of the conduction band levels of perovskite and the compact TiO 2 layer is thus essential for enhancing PSC performance. In this study, we demonstrate the shifting of the conduction band edge (CBE) of the compact TiO 2 layer through a TiCl 4 treatment, with the aim of improving PSC performance. The CBE of the compact TiO 2 layer was shifted to a higher level through the TiCl 4 treatment and then shifted in the opposite direction, that is, to a lower level, through a subsequent heat treatment. These shifts in the CBE were reflected in the PSC performance. The TiCl 4 -treated PSC showed an increase in the open-circuit voltage of more than 150 mV, as well as a decrease of 100 mV after being heated at 450 °C. On the other hand, the short-circuit current decreased after the treatment but increased after heating at temperatures higher than 300 °C. The treated PSC subjected to subsequent heating at 300 °C exhibited the best performance, with the power conversion efficiency of the PSC being 17% under optimized conditions.

Simple method of preparing nitrogen - doped nanosized TiO2 powders of high photocatalytic activity under visible light

International Nuclear Information System (INIS)

Nguyen Van Hung; Dang Thi Thanh Le

2014-01-01

Nitrogen-doped nanosized TiO 2 powders were prepared by a simple thermal treatment method of the mixture of titanium dioxide and urea. The prepared products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectra (UV-Vis-DRS) and Fourier transform infrared (FT-IR) spectroscopy. The results showed that the crystal structure of N-TiO 2 was a mixture of anatase and rutile phases, and the average particle size was 31 nm calculated from XRD results. The UV-vis spectra indicate an increase in absorption of visible light when compared to undoped TiO 2 . The photocatalytic activity of nitrogen-doped TiO 2 powder was evaluated by the decomposition of methylene blue under visible light irradiation. And it was found that nitrogen-doped TiO 2 powders exhibited much higher photocatalytic activity than undoped TiO 2 . Moreover, the study also showed that, the doping N atoms improve the growth of the TiO 2 crystal and phase transformation. (author)

Preparation and characterization of mesoporous TiO{sub 2}-sphere-supported Au-nanoparticle catalysts with high activity for CO oxidation at ambient temperature

Energy Technology Data Exchange (ETDEWEB)

Wang, Lili; Huang, Shouying; Zhu, Baolin; Zhang, Shoumin; Huang, Weiping, E-mail: hwp914@nankai.edu.cn [Nankai University, College of Chemistry, The Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), and Tianjin Key Lab of Metal and Molecule-based Material Chemistry (China)

2016-11-15

Mesoporous TiO{sub 2}-sphere-supported Au-nanoparticles (Au/m-TiO{sub 2}-spheres) catalysts have been synthesized by a simple method using tetrabutyl titanate as TiO{sub 2} precursor and characterized with XRD, BET, ICP, SEM, TEM, UV-Vis DRS, XPS, as well as FT-IR. The samples with the size in the range of 200–400 nm were almost perfectly spherical. The average diameter of pores was about 3.6 nm, and the mesopore size distribution was in the range of 2–6 nm with a narrow distribution. When the catalyst was calcined at 300 °C, the Au NPs with the size ca. 5 nm were highly dispersed on the surfaces of m-TiO{sub 2} spheres and partially embedded in the supports. Remarkably, the specific surface area of the Au/m-TiO{sub 2}-spheres was as high as 117 m{sup 2} g{sup −1}. The CO-adsorbed catalyst showed an apparent IR adsorption peak at 1714 cm{sup −1} that matched with bridging model CO. It means the catalysts should be of high catalytic activity for the CO oxidation due to they could adsorb and activate CO commendably. When Au-content was 0.48 wt.%, the Au/m-TiO{sub 2}-spheres could convert CO completely into CO{sub 2} at ambient temperature.

An innovative approach to synthesize highly-ordered TiO2 nanotubes.

Science.gov (United States)

Isimjan, Tayirjan T; Yang, D Q; Rohani, Sohrab; Ray, Ajay K

2011-02-01

An innovative route to prepare highly-ordered and dimensionally controlled TiO2 nanotubes has been proposed using a mild sonication method. The nanotube arrays were prepared by the anodization of titanium in an electrolyte containing 3% NH4F and 5% H2O in glycerol. It is demonstrated that the TiO2 nanostructures has two layers: the top layer is TiO2 nanowire and underneath is well-ordered TiO2 nanotubes. The top layer can easily fall off and form nanowires bundles by implementing a mild sonication after a short annealing time. We found that the dimensions of the TiO2 nanotubes were only dependent on the anodizing condition. The proposed technique may be extended to fabricate reproducible well-ordered TiO2 nanotubes with large area on other metals.

The efficacy of imagery rescripting (IR) for social phobia: a randomized controlled trial.

Science.gov (United States)

Lee, Seung Won; Kwon, Jung-Hye

2013-12-01

There is a need for brief effective treatment of social phobia and Imagery Rescripting (IR) is a potential candidate. The purpose of this study was to examine the efficacy of IR preceded by cognitive restructuring as a stand-alone brief treatment using a randomized controlled design. Twenty-three individuals with social phobia were randomly assigned to an IR group or to a control group. Participants in the IR group were provided with one session of imagery interviewing and two sessions of cognitive restructuring and Imagery Rescripting. Those in the control group had one session of clinical interviewing and two sessions of supportive therapy. Outcome measures including the Korean version of the social avoidance and distress scale (K-SADS) were administered before and after treatment, and at three-month follow-up. The short version of the Questionnaire upon Mental Imagery and the Traumatic Experience Scale were also administered before treatment. Participants in the IR group improved significantly on K-SADS and other outcome measures, compared to the control group. The beneficial effects of IR were maintained at three-month follow-up. It was also found that mental imagery ability and the severity of the traumatic experience did not moderate the outcome of IR. Further studies are needed to replicate the findings of our study using a large sample. The efficacy of IR as a stand-alone brief treatment was demonstrated for social phobia. The findings indicate that IR could be utilized as a cost-effective intervention for social phobia. Copyright © 2013 Elsevier Ltd. All rights reserved.

TiO₂ (rutile) embedded inulin--A versatile bio-nanocomposite for photocatalytic degradation of methylene blue.

Science.gov (United States)

Jayanthi Kalaivani, G; Suja, S K

2016-06-05

Inulin, a water soluble carbohydrate polymer, was extracted from Allium sativum L. by hot water diffusion method. A novel bio-nanocomposite was prepared by embedding TiO2 (rutile) onto the inulin matrix. The extracted inulin and the prepared bio-nanocomposite were characterized using UV-vis, FT-IR, XRD, SEM, TEM and TGA techniques. The photocatalytic activity of the bio-nanocomposite for the degradation of methylene blue was studied under UV illumination in batch mode experiment and was found to be twice as high as that of pristine TiO2. The kapp for inulin-TiO2 (0.0449 min(-1)) was higher than that for TiO2 (0.0325 min(-1)) which may be due to the synergistic action of inulin and TiO2. The stabilization of photo excited electron suppressed the electron-hole pair recombination thereby inducing the electrons and the holes to participate in the photo reduction and oxidation processes, respectively and enhancing the photocatalytic activity. Copyright © 2016 Elsevier Ltd. All rights reserved.

Visible light photoelectrocatalysis with salicylic acid-modified TiO2 nanotube array electrode for p-nitrophenol degradation

International Nuclear Information System (INIS)

Wang Xin; Zhao Huimin; Quan Xie; Zhao Yazhi; Chen Shuo

2009-01-01

This research focused on immersion method synthesis of visible light active salicylic acid (SA)-modified TiO 2 nanotube array electrode and its photoelectrocatalytic (PEC) activity. The SA-modified TiO 2 nanotube array electrode was synthesized by immersing in SA solution with an anodized TiO 2 nanotube array electrode. Scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (IR), UV-vis diffuse reflectance spectrum (DRS), and Surface photovoltage (SPV) were used to characterize this electrode. It was found that SA-modified TiO 2 nanotube array electrode absorbed well into visible region and exhibited enhanced visible light PEC activity on the degradation of p-nitrophenol (PNP). The degradation efficiencies increased from 63 to 100% under UV light, and 79-100% under visible light (λ > 400 nm), compared with TiO 2 nanotube array electrode. The enhanced PEC activity of SA-modified TiO 2 nanotube array electrode was attributed to the amount of surface hydroxyl groups introduced by SA-modification and the extension of absorption wavelength range.

Asbestos as 'toxic short-circuit' optic-fibre for UV within the cell-net: — Likely roles and hazards for secret UV and IR metabolism

International Nuclear Information System (INIS)

Traill, Robert R

2011-01-01

The most toxic asbestos fibres have widths 250nm-10nm, and this toxicity is 'physical', which could mean either mechanical or optical: Tangling with chromosomes is a mechanical hazard occasionally reported, and fibres 100nm wide — or chrysotile (white asbestos) is >150nm. In both cases, UV A /UV B -transmission would then predominate. (Chrysotile 150nm might be benign — escaping both mechanical and optical!). But what would generate such UV, and why would its transmission be toxic? Thar and Kühl (J.Theor.Biol.:2004) explain that the long mitochondria on microtubules may be able to act as UV-lasers, (and many observers since Gurwitsch 1923 have reported ultraweak UV emissions escaping from all types of living bio-tissue). That all suggests some universal secret role for UV, apparently related to mitosis. Insertion of fibre 'short-circuits' could then cause upsets in mitosis-control, and hence DNA irregularities. Such UV-control could parallel similar lower-powered Infra-Red control-systems (as considered elsewhere for coaxial myelin; or as portrayed by G.Albrecht-Buehler's online animations etc.); and the traditional short mitochondria seem better suited for this IR task.

FTIR and Raman Characterization of TiO2 Nanoparticles Coated with Polyethylene Glycol as Carrier for 2-Methoxyestradiol

Directory of Open Access Journals (Sweden)

Andrea León

2017-01-01

Full Text Available The aim of this study was to prepare a novel targeting drug delivery system for 2-Methoxyestradiol (2ME in order to improve the clinical application of this antitumor drug. It is based in nanoparticles (NPs of titanium dioxide (TiO2 coated with polyethylene glycol (PEG and loaded with 2ME. A complete IR and Raman characterization have been made to confirm the formation of TiO2–PEG–2ME composite. Vibrational modes have been assigned for TiO2, PEG, and 2ME and functionalized TiO2–PEG and TiO2–PEG–2ME. The observed variation in peak position of FTIR and Raman of each for these composites has been elucidated in terms of intermolecular interactions between PEG–2ME and TiO2, obtaining step-by-step the modification processes that were attributed to the conjugation of PEG and 2ME to TiO2 NPs. Modifying TiO2 NPs with PEG loaded with the 2ME drug revealed that the titanium dioxide nanocarrier possesses an effective adsorption capability, and we discuss their potential application as a system of drug delivery.

Detection and characterization with short TI inversion recovery MR imaging

Energy Technology Data Exchange (ETDEWEB)

Komata, Kaori (Nippon Medical School, Tokyo (Japan))

1994-10-01

Short TI inversion recovery magnetic resonance imaging (STIR-MRI) with spin echo (SE) T1- and T2-weighted images of the pelvis was investigated to evaluate its usefulness in detecting and characterizing endometriosis. Thirty-one women suspected of having the disease were studied in detail. MR findings with and without STIR-MRI were correlated with the results of laparotomy (27 women) and laparoscopy (4 women). Surgery revealed endometriosis in 29 women (17 ovarian chocolate cysts, 22 intestinal adhesions, 14 cul-de-sac obliterations and 12 adenomyosis). The other two women did not have endometriosis (uterine prolapse in one and submucosal leiomyoma in one). An ovarian chocolate cyst was diagnosed when a T1-elongated lesion showed shading, loculus or a low intensity rim on SE MR images, and a low intensity rim on STIR-MRI. Only 12 of the 17 chocolate cysts and neither of the two hemorrhagic corpus lutein cysts were correctly diagnosed on SE MR images, whereas 18 of these 19 cysts were correctly diagnosed because of the low intensity rim on STIR-MRI. In the pathological analysis, the rim was found to be a fibrous capsule and there were many macrophages which phagocytized hemosiderin. For the assessment of ovarian chocolate cysts, accuracy improved from 63.2% to 94.7%. As for the adhesion between the intestine and the uterus, specificity improved from 61.9% to 90.5% and accuracy improved from 67.7% to 93.5% when STRI-MRI was used. For the assessment of the cul-de-sac obliteration, accuracy improved from 67.7% to 83.8% although [chi][sup 2] analysis showed no significance. The major factors for the improved accuracy with STIR-MRI are the decrease of the motion artifact owing to the suppression of the fat signal, decreased chemical shift artifact and accurate differentiation of fat from hemorrhagic component. Therefore, STIR-MRI is a useful and reliable procedure and should be used together with SE T1-, T2-weighted images for the assessment of endometriosis. (author).

Detection and characterization with short TI inversion recovery MR imaging

International Nuclear Information System (INIS)

Komata, Kaori

1994-01-01

Short TI inversion recovery magnetic resonance imaging (STIR-MRI) with spin echo (SE) T1- and T2-weighted images of the pelvis was investigated to evaluate its usefulness in detecting and characterizing endometriosis. Thirty-one women suspected of having the disease were studied in detail. MR findings with and without STIR-MRI were correlated with the results of laparotomy (27 women) and laparoscopy (4 women). Surgery revealed endometriosis in 29 women (17 ovarian chocolate cysts, 22 intestinal adhesions, 14 cul-de-sac obliterations and 12 adenomyosis). The other two women did not have endometriosis (uterine prolapse in one and submucosal leiomyoma in one). An ovarian chocolate cyst was diagnosed when a T1-elongated lesion showed shading, loculus or a low intensity rim on SE MR images, and a low intensity rim on STIR-MRI. Only 12 of the 17 chocolate cysts and neither of the two hemorrhagic corpus lutein cysts were correctly diagnosed on SE MR images, whereas 18 of these 19 cysts were correctly diagnosed because of the low intensity rim on STIR-MRI. In the pathological analysis, the rim was found to be a fibrous capsule and there were many macrophages which phagocytized hemosiderin. For the assessment of ovarian chocolate cysts, accuracy improved from 63.2% to 94.7%. As for the adhesion between the intestine and the uterus, specificity improved from 61.9% to 90.5% and accuracy improved from 67.7% to 93.5% when STRI-MRI was used. For the assessment of the cul-de-sac obliteration, accuracy improved from 67.7% to 83.8% although χ 2 analysis showed no significance. The major factors for the improved accuracy with STIR-MRI are the decrease of the motion artifact owing to the suppression of the fat signal, decreased chemical shift artifact and accurate differentiation of fat from hemorrhagic component. Therefore, STIR-MRI is a useful and reliable procedure and should be used together with SE T1-, T2-weighted images for the assessment of endometriosis. (author)

Invited Article: Multiple-octave spanning high-energy mid-IR supercontinuum generation in bulk quadratic nonlinear crystals

Directory of Open Access Journals (Sweden)

Binbin Zhou

2016-08-01

Full Text Available Bright and broadband coherent mid-IR radiation is important for exciting and probing molecular vibrations. Using cascaded nonlinearities in conventional quadratic nonlinear crystals like lithium niobate, self-defocusing near-IR solitons have been demonstrated that led to very broadband supercontinuum generation in the visible, near-IR, and short-wavelength mid-IR. Here we conduct an experiment where a mid-IR crystal is pumped in the mid-IR. The crystal is cut for noncritical interaction, so the three-wave mixing of a single mid-IR femtosecond pump source leads to highly phase-mismatched second-harmonic generation. This self-acting cascaded process leads to the formation of a self-defocusing soliton at the mid-IR pump wavelength and after the self-compression point multiple octave-spanning supercontinua are observed. The results were recorded in a commercially available crystal LiInS2 pumped in the 3-4 μm range with 85 fs 50 μJ pulse energy, with the broadest supercontinuum covering 1.6-7.0 μm. We measured up 30 μJ energy in the supercontinuum, and the energy promises to scale favorably with an increased pump energy. Other mid-IR crystals can readily be used as well to cover other pump wavelengths and target other supercontinuum wavelength ranges.

Data on the effect of the dispersion of functionalized nanoparticles TiO2 with photocatalytic activity in LDPE

Directory of Open Access Journals (Sweden)

Alvarado Jahell

2018-02-01

Full Text Available This article contains the dataset referring to the article ''Study of the effect of the dispersion of functionalized nanoparticles TiO2 with photocatalytic activity in LDPE'' (Jahell et al., 2016 [1]. It includes the FT-IR data of the functionalized nanoparticles of TiO2 with Hexadecyltrimethoxysilane in different degrees of functionalization, thermogravimetric analysis, distribution and particle size in the polymer matrix by scanning electron microscopy (SEM, carbonyl index, gravimetry and scanning electron microscopy of the nanocomposite degraded by UV radiation.

Development of a flexible nanocomposite TiO{sub 2} film as a protective coating for bioapplications of superelastic NiTi alloys

Energy Technology Data Exchange (ETDEWEB)

Aun, Diego Pinheiro, E-mail: diegoaun@yahoo.com.br [Department of Metallurgical and Materials Engineering, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, 30270-901 Belo Horizonte, MG (Brazil); Houmard, Manuel, E-mail: mhoumard@ufmg.br [Department of Materials and Construction Engineering, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, 30270-901 Belo Horizonte, MG (Brazil); Mermoux, Michel, E-mail: michel.mermoux@lepmi.grenoble-inp.fr [LEPMI, Grenoble INP, rue de la Piscine—BP75 38402, Saint Martin d' Hères (France); Latu-Romain, Laurence, E-mail: laurence.latu-romain@simap.grenoble-inp.fr [SIR Team, Science et Ingénierie des Matériaux et Procédés, Grenoble INP, 1130, rue de la Piscine—BP75 38402, Saint Martin d' Hères (France); Joud, Jean-Charles, E-mail: jean-charles.joud@grenoble-inp.fr [SIR Team, Science et Ingénierie des Matériaux et Procédés, Grenoble INP, 1130, rue de la Piscine—BP75 38402, Saint Martin d' Hères (France); Berthomé, Gregory, E-mail: gregory.berthome@simap.grenoble-inp.fr [SIR Team, Science et Ingénierie des Matériaux et Procédés, Grenoble INP, 1130, rue de la Piscine—BP75 38402, Saint Martin d' Hères (France); Buono, Vicente Tadeu Lopes, E-mail: vbuono@demet.ufmg.br [Department of Metallurgical and Materials Engineering, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, 30270-901 Belo Horizonte, MG (Brazil)

2016-07-01

Highlights: • A NiTi alloy was coated with a flexible TiO{sub 2} protective layer via the sol–gel method. • Maximum flexibility was obtained with a nanocomposite crystalline/amorphous film. • The film reduces the Ni surface content, possibly improving the biocompatibility. - Abstract: An experimental procedure to coat superelastic NiTi alloys with flexible TiO{sub 2} protective nanocomposite films using sol–gel technology was developed in this work to improve the metal biocompatibility without deteriorating its superelastic mechanical properties. The coatings were characterized by scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and glazing incidence X-ray diffraction. The elasticity of the film was tested in coated specimens submitted to three-point bending tests. A short densification by thermal treatment at 500 °C for 10 min yielded a bilayer film consisting of a 50 nm-thick crystallized TiO{sub 2} at the inner interface with another 50-nm-thick amorphous oxide film at the outer interface. This bilayer could sustain over 6.4% strain without cracking and could thus be used to coat biomedical instruments as well as other devices made with superelastic NiTi alloys.

Comparison of mechanical behavior of TiN, TiNC, CrN/TiNC, TiN/TiNC films on 9Cr18 steel by PVD

Science.gov (United States)

Feng, Xingguo; Zhang, Yanshuai; Hu, Hanjun; Zheng, Yugang; Zhang, Kaifeng; Zhou, Hui

2017-11-01

TiN, TiNC, CrN/TiNC and TiN/TiNC films were deposited on 9Cr18 steel using magnetron sputtering technique. The morphology, composition, chemical state and crystalline structure of the films were observed and analyzed by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Hardness and adhesion force were tested by nanoindentation and scratch tester, respectively. The friction and wear behavior of TiN, TiNC, CrN/TiNC and TiN/TiNC films sliding against GCr15 balls were investigated and compared synthetically using ball-on-disk tribometer. It was found that Tisbnd N, Tisbnd C, Tisbnd Nsbnd C and Csbnd C bonds were formed. The TiN/TiNC film was composed of TiN, TiC and TiNC phases. Hardness and adhesion force results indicated that although the TiN film possessed the highest hardness, its adhesion force was lowest among all the films. Tribological test results showed that the friction coefficient of TiN/TiNC was much lower than that of TiN and the wear rate decreases remarkably from 2.3 × 10-15 m3/Nm to 7.1 × 10-16 m3/Nm, which indicated the TiN/TiNC film has better wear resistance.

TiO{sub 2} nanofiber solid-state dye sensitized solar cells with thin TiO{sub 2} hole blocking layer prepared by atomic layer deposition

Energy Technology Data Exchange (ETDEWEB)

Li, Jinwei; Chen, Xi; Xu, Weihe [Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ 07030 (United States); Nam, Chang-Yong, E-mail: cynam@bnl.gov [Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973 (United States); Shi, Yong, E-mail: Yong.Shi@stevens.edu [Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ 07030 (United States)

2013-06-01

We incorporated a thin but structurally dense TiO{sub 2} layer prepared by atomic layer deposition (ALD) as an efficient hole blocking layer in the TiO{sub 2} nanofiber based solid-state dye sensitized solar cell (ss-DSSC). The nanofiber ss-DSSCs having ALD TiO{sub 2} layers displayed increased open circuit voltage, short circuit current density, and power conversion efficiency compared to control devices with blocking layers prepared by spin-coating liquid TiO{sub 2} precursor. We attribute the improved photovoltaic device performance to the structural integrity of ALD-coated TiO{sub 2} layer and consequently enhanced hole blocking effect that results in reduced dark leakage current and increased charge carrier lifetime. - Highlights: • TiO{sub 2} blocking locking layer prepared by atomic layer deposition (ALD) method. • ALD-coated TiO{sub 2} layer enhanced hole blocking effect. • ALD blocking layer improved the voltage, current and efficiency. • ALD blocking layer reduced dark leakage current and increased electron lifetime.

Enhancement of photoelectric catalytic activity of TiO2 film via Polyaniline hybridization

International Nuclear Information System (INIS)

Wang Yajun; Xu Jing; Zong Weizheng; Zhu Yongfa

2011-01-01

A Polyaniline (PANI)/TiO 2 film coated on titanium foil was successfully prepared using the sol-gel method followed by a facile chemisorption. Compared with pristine TiO 2 , the photocatalytic (PC) and photoelectrocatalytic (PEC) degradation rates of 2,4-dichlorophenol (2,4-DCP) with the PANI/TiO 2 film were enhanced by 22.2% and 57.5%, respectively. 2,4-DCP can be mineralized more effectively in the presence of PANI/TiO 2 film. The best PEC degradation efficiency of 2,4-DCP with the PANI/TiO 2 film was acquired at an external potential of 1.5 V with a layer of 1 nm thick PANI. The PANI/TiO 2 film was characterized by Raman spectra, Fourier transform infrared spectra (FT-IR), Auger electron spectroscopy (AES), and electrochemical analysis. These results indicated that there was a chemical interaction on the interface of PANI and TiO 2 . This interaction may be of significance to promote the migration efficiency of carriers and induce a synergetic effect to enhance the PC and PEC activities. - Graphical abstract: The effect of PANI content on 2,4-DCP degradation with initial concentration of 50 mg/L, external potential=1.5 V. Inset: degradation rate constants of various PANI/TiO 2 films. Highlights: → Polyaniline/TiO 2 film was prepared using the sol-gel method followed by chemisorption. → Photoelectrocatalytic degradation rate of 2,4-dichlorophenol was enhanced by 57.5%. → The modification of Polyaniline to TiO 2 film caused a rapid charge separation. → Best degradation efficiency was acquired at 1.5 V with 1 nm thick PANI.

Laser induced photocurrent and photovoltage transient measurements of dye-sensitized solar cells based on TiO_2 nanosheets and TiO_2 nanoparticles

International Nuclear Information System (INIS)

Ghaithan, Hamid M.; Qaid, Saif M.H.; Hezam, Mahmoud; Labis, Joselito P.; Alduraibi, Mohammad; Bedja, Idriss M.; Aldwayyan, Abdullah S.

2016-01-01

Dye-sensitized solar cells (DSSCs) based on TiO_2 nanoparticles and TiO_2 nanosheets with exposed {001} facets are investigated using laser-induced photovoltage and photocurrent transient decay (LIPVCD) measurements. We adopted a simplified version of LIPVCD technique, in which a single illumination light source and a laboratory oscilloscope could be conveniently used for the measurements. Although the {001} surface of TiO_2 nanosheets allowed a noticeably slower recombination with the electrolyte, this was counterpoised by a slower electron transport probably due to its planar morphology, resulting in a shorter diffusion length in TiO_2 nanosheets. The nanosheet morphology also resulted in less surface area and therefore reduced short circuit current density in the fabricated devices. Our work highlights the fact that the morphological parameters of TiO_2 nanosheets finally resulting after electrode film deposition is of no less importance than the reported efficient dye adsorption and slow electron recombination at the surface of individual nanosheets.

An investigation into the Ti-grafting structure on MCM-41 and epoxidation catalysis

DEFF Research Database (Denmark)

Yuan, Q.C.; Hagen, A.; Roessner, F.

2006-01-01

The structure of titanium species grafted on a purely siliceous MCM-41 and their catalysis in the epoxidation of cyclohexene with tert-butyl hydroperoxide (TBHP) were investigated. FT-IR, XANES and UV-vis were used for the examination of the Ti-grafted MCM-41. The results indicated...... that the titanium atoms are grafted on the wall surface of the MCM-41 by four-fold coordination. The four-fold coordinated titanium species are mainly grafted by two or one -O-Si-O- bridges on the MCM-41, resulting in so-called bipodal or monopodal titanium centres in partially polymerised states. The ratio...... of monopodal to bipodal titanium increases with the increase in Ti-content. These partially polymerised titanium species considered as catalytic active centres have high activity and selectivity in the epoxidation reaction. The used Ti-grafted MCM-41 samples were regenerated by heating in nitrogen or air...

Preparation and characterisation of visible light responsive iodine doped TiO2 electrodes

International Nuclear Information System (INIS)

Lisowska-Oleksiak, Anna; Szybowska, Katarzyna; Jasulaitiene, Vitalija

2010-01-01

Characteristics are presented of new iodine doped TiO 2 (I-TiO 2 ) prepared via the hydrothermal method, where titania (IV) complexes with a ligand containing an iodine atom have been used as a precursor. The structure of samples has been examined by XPS, XRD, UV-vis and FT-IR-ATR techniques. These studies confirm that the obtained powder exhibits a decrease in the bandgap energy value (E g = 2.8 eV). The report presents electrochemical studies of I-TiO 2 films on a Pt electrode, which allow determination of the flatband potential E fb = -0.437 V vs. SCE (in 0.5 M Na 2 SO 4 ). Cyclic voltammetry measurements show anodic and cathodic activities under Vis and UV-vis radiation. The photocurrent enhancement due to visible light radiation reached 30% of the whole photoacitivity exhibited under UV-vis illumination.

W-doped TiO2 photoanode for high performance perovskite solar cell

International Nuclear Information System (INIS)

Liu, Jinwang; Zhang, Jing; Yue, Guoqiang; Lu, Xingwei; Hu, Ziyang; Zhu, Yuejin

2016-01-01

Titanium dioxide (TiO 2 ) with dispersed W-doping shows its capability for efficient electron collection from perovskite to TiO 2 in perovskite solar cell. The conduction band (CB) of TiO 2 moves downward (positive shift) with increasing the tungsten (W) content, which enlarges the energy gap between the CB of TiO 2 and the perovskite. Thus, the efficiency of electron injection from perovskite to TiO 2 is increased. Due to the increased electron injection, W-doped TiO 2 (≤0.2% W content) enhances the short-circuit photocurrent (J sc ) of perovskite solar cell and improves the performance of perovskite solar cell. Perovskite solar cell with 0.1% W-doped photoanode obtains the highest power conversion efficiency (η = 10.6%), which shows enhancement by 13% in J sc and by 17% in η, as compared with the undoped TiO 2 perovskite solar cell.

Electrosynthesis of Polyaniline-TiO2 Nanocomposite Films on Aluminum Alloy 3004 Surface and its Corrosion Protection Performance

Directory of Open Access Journals (Sweden)

M. Shabani-Nooshabadi

2013-03-01

Full Text Available The direct synthesis of polyaniline-TiO2 nanocomposite coatings on aluminum alloy 3004 (AA3004 surface has been investigated by using the galvanostatic method. The synthesized coatings were characterized by FT-IR, SEM-EDX, SEM and AFM. Optical absorption spectroscopy reveals the formation of the emeraldine oxidation state form of polyaniline-TiO2 nanocomposite. The corrosion performances of polyaniline-TiO2 nanocomposite coatings were investigated in 3.5% NaCl solution by Tafel polarization and Electrochemical Impedance Spectroscopy (EIS methods. The corrosion rate of polyaniline-TiO2 nanocomposite coating on AA3004 was found ∼260 times lower than bare AA3004 and corrosion potentials of these coatings have shifted to more positive potentials (105 mV. The results of this study clearly ascertain that the polyaniline-TiO2 nanocomposite coating has outstanding potential to protect the AA3004 against corrosion in a chloride environment.

Field Optimization for short Period Undulators

CERN Document Server

Peiffer, P; Rossmanith, R; Schoerling, D

2011-01-01

Undulators dedicated to low energy electron beams, like Laser Wakefield Accelerators, require very short period lengths to achieve X-ray emission. However, at these short period length (LambdaU ~ 5 mm) it becomes difficult to reach magnetic field amplitudes that lead to a K parameter of >1, which is generally desired. Room temperature permanent magnets and even superconductive undulators using Nb-Ti as conductor material have proven insufficient to achieve the desired field amplitudes. The superconductor Nb$_{3}$Sn has the theoretical potential to achieve the desired fields. However, up to now it is limited by several technological challenges to much lower field values than theoretically predicted. An alternative idea for higher fields is to manufacture the poles of the undulator body from Holmium instead of iron or to use Nb-Ti wires with a higher superconductor/copper ratio. The advantages and challenges of the different options are compared in this contribution.

Electronic structure of layered ferroelectric high-k titanate Pr{sub 2}Ti{sub 2}O{sub 7}

Energy Technology Data Exchange (ETDEWEB)

Atuchin, V.V., E-mail: atuchin@thermo.isp.nsc.ru [Laboratory of Optical Materials and Structures, Institute of Semiconductor Physics, SB RAS, Novosibirsk 90, 630090 (Russian Federation); Gavrilova, T.A. [Laboratory of Nanodiagnostics and Nanolithography, Institute of Semiconductor Physics, SB RAS, Novosibirsk 90, 630090 (Russian Federation); Grivel, J.-C. [Materials Research Division, National Laboratory for Sustainable Energy, Technical University of Denmark, Frederiksborgvej 399, DK-4000, Roskilde (Denmark); Kesler, V.G. [Laboratory of Physical Bases of Integrated Microelectronics, Institute of Semiconductor Physics, SB RAS, Novosibirsk 90, 630090 (Russian Federation); Troitskaia, I.B. [Laboratory of Optical Materials and Structures, Institute of Semiconductor Physics, SB RAS, Novosibirsk 90, 630090 (Russian Federation)

2012-11-15

The spectroscopic parameters and electronic structure of binary titanate Pr{sub 2}Ti{sub 2}O{sub 7} have been studied by IR-, Raman and X-ray photoelectron spectroscopy (XPS) for the powder sample prepared by solid state synthesis. The spectral features of valence band and all constituent element core levels have been considered. The Auger parameters of titanium and oxygen in Pr{sub 2}Ti{sub 2}O{sub 7} have been determined as {alpha}{sub Ti}=872.8 and {alpha}{sub O}=1042.3 eV. Variations of cation-anion bond ionicity have been discussed using binding energy differences {Delta}{sub Ti}=(BE O 1s-BE Ti 2p{sub 3/2})=71.6 eV and {Delta}{sub Pr}=BE(Pr 3d{sub 5/2})-BE(O 1s)=403.8 eV as key parameters in comparison with those of other titanium- and praseodymium-bearing oxides. Highlights: Black-Right-Pointing-Pointer Solid state synthesis of polar titanate Pr{sub 2}Ti{sub 2}O{sub 7}. Black-Right-Pointing-Pointer Structural and spectroscopic properties and electronic structure determination. Black-Right-Pointing-Pointer Ti-O and Pr-O bonding analysis using Ti 2p{sub 3/2}, Pr 3d{sub 5/2} and O 1s core levels.

Visible light assisted photodecolorization of eosin-Y in aqueous solution using hesperidin modified TiO{sub 2} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Vignesh, K. [P.G. and Research Department of Chemistry, Thiagarajar College, Madurai, Tamilnadu 625009 (India); Suganthi, A., E-mail: suganthiphd09@gmail.com [P.G. and Research Department of Chemistry, Thiagarajar College, Madurai, Tamilnadu 625009 (India); Rajarajan, M., E-mail: rajarajan_1962@yahoo.com [Department of Chemistry, C.P.A. College, Bodinayakanur, Tamilnadu 626513 (India); Sakthivadivel, R. [P.G. and Research Department of Chemistry, Thiagarajar College, Madurai, Tamilnadu 625009 (India)

2012-03-01

Hesperidin a flavanoid, modified TiO{sub 2} nanoparticles (Hes-TiO{sub 2}) was synthesized to improve the visible light driven photocatalytic performance of TiO{sub 2}. The synthesized nanoparticles were characterized by UV-visible diffuse reflectance spectroscopy (UV-vis-DRS), FT-IR, powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The photocatalytic activity of Hes-TiO{sub 2} was investigated based on the decolorization of eosin-Y under visible light irradiation. Hes-TiO{sub 2} showed high efficiency for the decolorization of eosin-Y. The influences of various reaction parameters like effect of pH, catalyst dosage and initial dye concentration on the photocatalytic efficiency were investigated. The adsorption of eosin-Y on Hes-TiO{sub 2} was found favorable by the Langmuir approach. The removal percentage of chemical oxygen demand (COD) was determined to evaluate the mineralization of eosin-Y during photodecolorization. Based on the intermediates obtained in the GC-MS spectroscopic technique, a probable degradation mechanism has been proposed.

Bioactivity studies on TiO2-bearing Na2O–CaO–SiO2–B2O3 glasses

International Nuclear Information System (INIS)

Jagan Mohini, G.; Sahaya Baskaran, G.; Ravi Kumar, V.; Piasecki, M.; Veeraiah, N.

2015-01-01

Soda lime silica borate glasses mixed with different concentrations of TiO 2 are synthesized by the melt-quenching technique. As a part of study on bioactivity of these glasses, the samples were immersed in simulated body fluid (SBF) solution for prolonged times (~ 21 days) during which weight loss along with pH measurements is carried out at specific intervals of time. The XRD and SEM analyses of post-immersed samples confirm the formation of crystalline hydroxyapatite layer (HA) on the surface of the samples. To assess the role of TiO 2 on the formation of HA layer and degradability of the samples the spectroscopic studies viz. optical absorption and IR spectral studies on post- and pre-immersed samples have been carried out. The analysis of the results of degradability together with spectroscopic studies as a function of TiO 2 concentration indicated that about 6.0 mol% of TiO 2 is the optimal concentration for achieving better bioactivity of these glasses. The presence of the maximal concentration octahedral titanium ions in this glass that facilitates the formation of HA layer is found to be the reason for such a higher bioactivity. - Highlights: • Soda lime silica borate glasses mixed with TiO 2 are synthesized. • Bioactivity of the glasses is studied by immersing them in SBF solution. • XRD and SEM studies indicated the formation of hydroxyapatite layer on the surface. • Quantum of degradability is the highest in the glasses mixed with 6.0 mol% of TiO 2. • The results are analyzed using IR and optical absorption studies

Improved designs of Si-based quantum wells and Schottky diodes for IR detection

Energy Technology Data Exchange (ETDEWEB)

Moeen, M., E-mail: moeen@kth.se [School of Information and Communication Technology, KTH Royal Institute of Technology, Stockholm, 16640, Kista (Sweden); Kolahdouz, M. [School of Electrical and Computer Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Salemi, A.; Abedin, A.; Östling, M. [School of Information and Communication Technology, KTH Royal Institute of Technology, Stockholm, 16640, Kista (Sweden); Radamson, H.H., E-mail: rad@kth.se [School of Information and Communication Technology, KTH Royal Institute of Technology, Stockholm, 16640, Kista (Sweden)

2016-08-31

Novel structures of intrinsic or carbon-doped multi quantum wells (MQWs) and intrinsic or carbon-doped Si Schottky diodes (SD), individually or in combination, have been manufactured to detect the infrared (IR) radiation. The carbon concentration in the structures was 5 × 10{sup 20} cm{sup −3} and the MQWs are located in the active part of the IR detector. A Schottky diode was designed and formed as one of the contacts (based on NiSi(C)/TiW) to MQWs where on the other side the structure had an Ohmic contact. The thermal response of the detectors is expressed in terms of temperature coefficient of resistance (TCR) and the quality of the electrical signal is quantified by the signal-to-noise ratio. The noise measurements provide the K{sub 1/f} parameter which is obtained from the power spectrum density. An excellent value of TCR = − 6%/K and K{sub 1/f} = 4.7 × 10{sup −14} was measured for the detectors which consist of the MQWs in series with the SD. These outstanding electrical results indicate a good opportunity to manufacture low cost Si-based IR detectors in the near future. - Highlights: • SiGe (C)/Si(C) multi quantum wells (MQWs) are evaluated to detect IR radiation. • Schottky diodes (SDs), individually or in series with MQWs are also fabricated. • Detectors consisted of MQWs in series with SD show excellent thermal sensing. • The noise values are also extremely low for MQWs in series with SD.

Improved designs of Si-based quantum wells and Schottky diodes for IR detection

International Nuclear Information System (INIS)

Moeen, M.; Kolahdouz, M.; Salemi, A.; Abedin, A.; Östling, M.; Radamson, H.H.

2016-01-01

Novel structures of intrinsic or carbon-doped multi quantum wells (MQWs) and intrinsic or carbon-doped Si Schottky diodes (SD), individually or in combination, have been manufactured to detect the infrared (IR) radiation. The carbon concentration in the structures was 5 × 10 20 cm −3 and the MQWs are located in the active part of the IR detector. A Schottky diode was designed and formed as one of the contacts (based on NiSi(C)/TiW) to MQWs where on the other side the structure had an Ohmic contact. The thermal response of the detectors is expressed in terms of temperature coefficient of resistance (TCR) and the quality of the electrical signal is quantified by the signal-to-noise ratio. The noise measurements provide the K 1/f parameter which is obtained from the power spectrum density. An excellent value of TCR = − 6%/K and K 1/f = 4.7 × 10 −14 was measured for the detectors which consist of the MQWs in series with the SD. These outstanding electrical results indicate a good opportunity to manufacture low cost Si-based IR detectors in the near future. - Highlights: • SiGe (C)/Si(C) multi quantum wells (MQWs) are evaluated to detect IR radiation. • Schottky diodes (SDs), individually or in series with MQWs are also fabricated. • Detectors consisted of MQWs in series with SD show excellent thermal sensing. • The noise values are also extremely low for MQWs in series with SD.

Oxidation Kinetics of Cast TiAl3

Science.gov (United States)

Smialek, J. L.; Humphrey, D. L.

1992-01-01

The isothermal oxidation kinetics of the TiAl3 compound over a wide temperature range is documented, and these rates are related to exclusive alpha-Al2O3 scale growth. The specific weight change vs time curves are shown. Two abnormalities are immediately apparent. One is that a rapid initial uptake of oxygen occurs at times less than 5 h, followed by a lower oxidation rate at longer times, for tests at 900 C and below. The other is that the final weight changes for the 700, 800, and 900 C tests are not in the sequence expected with respect to temperature. Isothermal oxidation of drop cast TiAl above 1000 C was found to exhibit parabolic oxidation controlled by protective alpha-Al2O3 scale formation. TiAl is the only phase in the binary Ti-Al system that forms exclusive scales of alpha-Al2O3 in isothermal oxidation. High anomalous rates at short times and at temperatures below 1000 C resulted from the internal oxidation of a second phase of aluminum.

Genotoxic and cytotoxic activity of green synthesized TiO2 nanoparticles

Science.gov (United States)

Koca, Fatih Doğan; Duman, Fatih

2018-03-01

Nowadays, nanomaterials that are smaller than 100 nm in size are very attractive owing to their enhanced physicochemical properties. Although they have been used widely for industrial applications, their toxicity still remains a problem. This article is a new record of the synthesis of titanium dioxide nanoparticles (TiO2 NPs) by a Mentha aquatica leaf extract and determination of its toxicity to rat marrow mesenchymal stem cells. In this study, we aimed to determine the genotoxic and cytotoxic effects of biologically synthetized TiO2 NPs. The characteristic peak of the nanomaterial was observed at 354 nm. The mean size of the nanomaterial was measured to be 69 nm from SEM images. According to zeta analysis, the surface charge of the nanomaterial was - 37.6 mV. The crystalline structure of the nanomaterial was determined using XRD analysis. It was concluded that the obtained nanomaterial was TiO2 The results of the FT-IR analysis showed that the functional groups that were found in the plant extract could play an important role in the formation and stabilization of TiO2 NPs. The effective size of the TiO2 NPs was found to be 304 nm using DLS analysis. The TGA analysis results showed that the total mass loss was 4% at 900 °C. According to DNA cleavage analysis results, TiO2 NPs cause damage to the plasmid pBR322 DNA in a concentration-dependant matter. It has been noted that TiO2 NPs lead to decreased cell viability during increased time and concentration of applications on rat marrow mesenchymal stem cells. It has also been determined that bulk TiO2 causes a greater reduction in the stem cell viability compared to the biosynthesized NPs. The obtained results could be useful for further application and toxicity studies.

Spin orientations of the spin-half Ir(4+) ions in Sr3NiIrO6, Sr2IrO4, and Na2IrO3: Density functional, perturbation theory, and Madelung potential analyses.

Science.gov (United States)

Gordon, Elijah E; Xiang, Hongjun; Köhler, Jürgen; Whangbo, Myung-Hwan

2016-03-21

The spins of the low-spin Ir(4+) (S = 1/2, d(5)) ions at the octahedral sites of the oxides Sr3NiIrO6, Sr2IrO4, and Na2IrO3 exhibit preferred orientations with respect to their IrO6 octahedra. We evaluated the magnetic anisotropies of these S = 1/2 ions on the basis of density functional theory (DFT) calculations including spin-orbit coupling (SOC), and probed their origin by performing perturbation theory analyses with SOC as perturbation within the LS coupling scheme. The observed spin orientations of Sr3NiIrO6 and Sr2IrO4 are correctly predicted by DFT calculations, and are accounted for by the perturbation theory analysis. As for the spin orientation of Na2IrO3, both experimental studies and DFT calculations have not been unequivocal. Our analysis reveals that the Ir(4+) spin orientation of Na2IrO3 should have nonzero components along the c- and a-axis directions. The spin orientations determined by DFT calculations are sensitive to the accuracy of the crystal structures employed, which is explained by perturbation theory analyses when interactions between adjacent Ir(4+) ions are taken into consideration. There are indications implying that the 5d electrons of Na2IrO3 are less strongly localized compared with those of Sr3NiIrO6 and Sr2IrO4. This implication was confirmed by showing that the Madelung potentials of the Ir(4+) ions are less negative in Na2IrO3 than in Sr3NiIrO6 and Sr2IrO4. Most transition-metal S = 1/2 ions do have magnetic anisotropies because the SOC induces interactions among their crystal-field split d-states, and the associated mixing of the states modifies only the orbital parts of the states. This finding cannot be mimicked by a spin Hamiltonian because this model Hamiltonian lacks the orbital degree of freedom, thereby leading to the spin-half syndrome. The spin-orbital entanglement for the 5d spin-half ions Ir(4+) is not as strong as has been assumed.

In vitro and in vivo performance of bioactive Ti6Al4V/TiC/HA implants fabricated by a rapid microwave sintering technique.

Science.gov (United States)

Choy, Man Tik; Tang, Chak Yin; Chen, Ling; Wong, Chi Tak; Tsui, Chi Pong

2014-09-01

Failure of the bone-implant interface in a joint prosthesis is a main cause of implant loosening. The introduction of a bioactive substance, hydroxyapatite (HA), to a metallic bone-implant may enhance its fixation on human bone by encouraging direct bone bonding. Ti6Al4V/TiC/HA composites with a reproducible porous structure (porosity of 27% and pore size of 6-89 μm) were successfully fabricated by a rapid microwave sintering technique. This method allows the biocomposites to be fabricated in a short period of time under ambient conditions. Ti6Al4V/TiC/HA composites exhibited a compressive strength of 93 MPa, compressive modulus of 2.9 GPa and microhardness of 556 HV which are close to those of the human cortical bone. The in vitro preosteoblast MC3T3-E1 cells cultured on the Ti6Al4V/TiC/HA composite showed that the composite surface could provide a biocompatible environment for cell adhesion, proliferation and differentiation without any cytotoxic effects. This is among the first attempts to study the in vivo performance of load-bearing Ti6Al4V/TiC and Ti6Al4V/TiC/HA composites in a live rabbit. The results indicated that the Ti6Al4V/TiC/HA composite had a better bone-implant interface compared with the Ti6Al4V/TiC implant. Based on the microstructural features, the mechanical properties, and the in vitro and in vivo test results from this study, the Ti6Al4V/TiC/HA composites have the potential to be employed in load-bearing orthopedic applications. Copyright © 2014 Elsevier B.V. All rights reserved.

One-pot synthesis of polyaniline-doped in mesoporous TiO2 and its electrorheological behavior

International Nuclear Information System (INIS)

Wei Chuan; Zhu Yihua; Yang Xiaoling; Li Chunzhong

2007-01-01

A class of hybrid organic-inorganic composite for application in electrorheological (ER) fluid was prepared by using a simple one-pot method. Transmission electron microscopy (TEM) image shows that the synthesized material had a mesoporous structure. X-ray diffraction (XRD) further proves that the pore size is about 7.4 nm with an anatase TiO 2 framework. Fourier transform infrared (FT-IR) and nitrogen sorption curve reveal polyaniline (PANI) is doped in mesochannels. The ER behaviors of PANI/TiO 2 in silicone oil are invesigated with different doping degrees under different electric fields. The results obtained provide more insight into the role of proper doping in ER fluid

Synthesis and electronic properties of LnRhAsO and LnIrAsO compositions

International Nuclear Information System (INIS)

Muir, Sean; Sleight, A.W.; Subramanian, M.A.

2011-01-01

The synthesis and characterization of the new compositions LnRhAsO (Ln=Ce, Nd) and LnIrAsO (Ln=La, Ce, Nd) are reported. These compounds crystallize in the ZrCuSiAs type structure, isostructural to iron pnictide LnFeAsO materials. Upon substitution of Rh for Fe, both a and c lattice parameters increase relative to 3d transition metal compounds; however, when Ir is substituted for Rh the a-parameter decreases slightly while the c-parameter expands. The decrease in a lattice parameter corresponds to a short metal-metal distance in Ir compounds. CeRhAsO and CeIrAsO compositions show abrupt decreases in resistivity at 7 and 10 K, respectively, coinciding with a small shift in magnetization at the transition temperature. - Graphical abstract: LnIrAsO (Ln=La, Ce, Nd) and LnRhAsO (Ln=Ce, Rh) have been synthesized. These new transition metal oxypnictide compositions are isostructural to LaFeAsO. The 5d Ir compositions demonstrate a shorter metal-metal interaction than the 4d Rh compositions. Highlights: → LnIrAsO (Ln=La, Ce, Nd) and LnRhAsO (Ln=Ce, Nd) have been synthesized. → Ir compositions show a decreased a-parameter and increased c-parameter relative to Rh compositions. → All LnIrAsO and LnRhAsO compositions are metallic while CeIrAsO and CeRhAsO show a sudden drop in resistivity at 10 and 7 K, respectively.

Factors influencing formation of highly dispersed BaTiO3 nanospheres with uniform sizes in static hydrothermal synthesis

International Nuclear Information System (INIS)

Gao, Jiabing; Shi, Haiyue; Dong, Huina; Zhang, Rui; Chen, Deliang

2015-01-01

Highly dispersed BaTiO 3 nanospheres with uniform sizes have important applications in micro/nanoscale functional devices. To achieve well-dispersed spherical BaTiO 3 nanocrystals, we carried out as reported in this paper the systematic investigation on the factors that influence the formation of BaTiO 3 nanospheres by the static hydrothermal process, including the NaOH concentrations [NaOH], molar Ba/Ti ratios (R Ba/Ti ), hydrothermal temperatures, and durations, with an emphasis on understanding the related mechanisms. Barium nitrate and TiO 2 sols derived from tetrabutyl titanate were used as the starting materials. The as-synthesized BaTiO 3 samples were characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, thermogravimetry, differential thermal analysis, and FT-IR spectra. The highly dispersed BaTiO 3 nanospheres (76 ± 13 nm) were achieved under the optimum hydrothermal conditions at 200 °C for 10 h: [NaOH] = 2.0 mol L −1 and R Ba/Ti  = 1.5. Higher NaOH concentrations, higher Ba/Ti ratios, higher hydrothermal temperatures, and longer hydrothermal durations are favorable in forming BaTiO 3 nanospheres with larger fractions of tetragonal phase and higher yields; but too long hydrothermal durations resulted in abnormal growth and reduced the uniformity in particle sizes. The possible formation mechanisms for BaTiO 3 nanocrystals under the static hydrothermal conditions were investigated

Anatomy-performance correlation in Ti-based contact metallizations on AlGaN/GaN heterostructures

International Nuclear Information System (INIS)

Mohammed, Fitih M.; Wang, Liang; Koo, Hyung Joon; Adesida, Ilesanmi

2007-01-01

A comprehensive study of the electrical and surface microstructural characteristics of Ti/Au, Ti/Al/Au, Ti/Mo/Au, and Ti/Al/metal/Au schemes, where metal is Ir, Mo, Nb, Pt, Ni, Ta, and Ti, has been carried out to determine the role of constituent components of multilayer contact metallizations on Ohmic contact formation on AlGaN/GaN heterostructures. Attempts have been made to elucidate the anatomy (composition-structure) performance correlation in these schemes. Evidences have been obtained for the necessity of the Al and metal barrier layer as well as an optimal amount of Ti for achieving low-resistance Ohmic contact formation. A strong dependence of electrical properties and intermetallic interactions on the type of metal barrier layer used was found. Scanning electron microscopy characterization, coupled with energy dispersive x-ray spectroscopy, has shown evidence for alloy aggregation, metal layer fragmentation, Al-Au solid solution formation, and possible Au and/or Al reaction with metal layer. Results from the present study provide insights on the active and the necessary role various components of a multilayer contact metallization play for obtaining excellent Ohmic contact formation in the fabrication of AlGaN/GaN high electron mobility transistors

Microstructure and corrosion resistance of TC2 Ti alloy by laser cladding with Ti/TiC/TiB_2 powders

International Nuclear Information System (INIS)

Diao, Yunhua; Zhang, Kemin

2015-01-01

Highlights: • A TiC/TiB_2 composite coating was produced onto a TC2 Ti alloy by laser cladding with Ti/TiC/TiB_2 powders. • A maximum hardness of 1100 HV was achieved in the laser clad TiC/TiB_2 composite layer. • Corrosion resistance of the TC2 alloy in NaCl (3.5 wt%) aqueous solution can be improved after laser cladding. - Abstract: In the present work, a TiC/TiB_2 composite coating was produced onto a TC2 Ti alloy by laser cladding with Ti/TiC/TiB_2 powders. The surface microstructure, phase components and compositions were characterized with methods of optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffractometry (XRD), and energy dispersive spectrometry (EDS). The cladding layer is consisted of Ti, TiC and TiB_2. And the surface microhardness was measured. After laser cladding, a maximum hardness of 1100 HV is achieved in the laser cladding surface layer, which is more three times higher than that of the TC2 substrate (∼300 HV). Due to the formation of TiC and TiB_2 intermetallic compounds in the alloyed region and grain refinement, the microhardness of coating is higher than TC2 Ti alloy. In this paper, the corrosion property of matrix material and treated samples were both measured in NaCl (3.5 wt%) aqueous solution. From the result we can see that the laser cladding specimens’ corrosion property is clearly becoming better than that of the substrate.

Internal friction study of neutron-irradiation effects on an amorphous Cu40Ti60 alloy

International Nuclear Information System (INIS)

Dong, Y.; Wu, G.; Xiao, K.; Li, X.; He, Y.

1988-01-01

Effects of neutron irradiation on the structure of an amorphous Cu 40 Ti 60 alloy have been studied by internal friction measurements. After irradiation, the position of the first internal friction peak remains almost unchanged and the shoulder position shifts towards a higher temperature by about 5 K, which indicates that the Cu 40 Ti 60 glass becomes more stable. These results are finally discussed based on the concept of changes of chemical short-range ordering and geometrical short-range ordering due to radiation damage

Bond Shortening (1.4 Å) in the Singlet and Triplet Excited States of [Ir2(dimen)4]2+ in Solution Determined by Time-Resolved X-ray Scattering

DEFF Research Database (Denmark)

Haldrup, Martin Kristoffer; Harlang, Tobias; Christensen, Morten

2011-01-01

Ground- and excited-state structures of the bimetallic, ligand-bridged compound Ir2(dimen)42+ are investigated in acetonitrile by means of time-resolved X-ray scattering. Following excitation by 2 ps laser pulses at 390 nm, analysis of difference scattering patterns obtained at eight different ti...

Ionic Liquid-assisted Synthesis of Cellulose/TiO2 Composite and Photocatalytic Performance

Directory of Open Access Journals (Sweden)

ZHU Mo-shuqi

2016-12-01

Full Text Available Cellulose/TiO2 composite was prepared by sol-gel method using the ionic liquid BMIMCl as reactive medium and Ti(OBu4 as a precursor. The synthesis conditions were optimized by single-factor experiment. The structure and properties of the composite were characterized by scanning electron microscope (SEM,X-ray diffraction(XRD,Fourier transform infrared spectoscopy(FT-IR,UV-vis-diffuse reflectance spectroscope(DRS and thermogravimetric (TG analysis. The photocatalytic activity of the composite was investigated via testing the photodegradation of methyl orange in aqueous suspension under UV-light. The results show that the high active photocatalytic composite is prepared by using ionic liquid BMIMCl as medium at room temperature and atmospheric pressure. The photo catalytic degradation rate of composite on methyl orange(MO reaches 97.09% in 80min. Comparing with bare TiO2, the degradation rate of MO increases by 37%. Moreover, the composite still shows 62.66% degradation rate towards MO after recycling 4 times.

Kinetic study of the catalytic pyrolysis of elephant grass using Ti-MCM-41

Energy Technology Data Exchange (ETDEWEB)

Fontes, Maria do Socorro Braga; Melo, Dulce Maria de Araujo; Rodrigues, Glicelia, E-mail: socorro.fontes@yahoo.com.br [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil); Barros, Joana Maria de Farias [Universidade Federal de Campina Grande (UFCG), Cuite, PB (Brazil). Dept. de Quimica; Braga, Renata Martins [Universidade Federal da Paraiba (UFPB/CEAR/DEER), Joao Pessoa, PB (Brazil). Centro de Energias Alternativas e Renovaveis. Dept. de Engenharia de Energia Renovaveis

2014-08-15

This work aimed to study the kinetics of thermal and catalytic pyrolysis using Ti-MCM-41 as catalyst in order to assess the catalytic pyrolysis efficiency compared to thermal pyrolysis of elephant grass. Ti-MCM-41 molecular sieve was synthesized by hydrothermal method from hydrogel with the following molar composition: 1.00 CTMABr: 4.00 SiO{sub 2}:X TiO{sub 2}: 1 + X Na{sub 2}O: 200.00 H{sub 2}O, which structure template used was cetyltrimethylammonium bromide (CTMABr). The materials synthesized were characterized by X-ray diffraction, IR spectroscopy, thermogravimetric analysis and specific area by the BET method, for subsequent application in the biomass pyrolysis process. The kinetic models proposed by Vyazovkin and Flynn-Wall were used to determine the apparent activation energy involved in the thermal and catalytic pyrolysis of elephant grass and the results showed that the catalyst used was effective in reducing the apparent activation energy involved in the thermal decomposition of elephant grass. (author)

Sol-gel synthesis of TiO2-SiO2 photocatalyst for β-naphthol photodegradation

International Nuclear Information System (INIS)

Qourzal, S.; Barka, N.; Tamimi, M.; Assabbane, A.; Nounah, A.; Ihlal, A.; Ait-Ichou, Y.

2009-01-01

Silica gel supported titanium dioxide particles (TiO 2 -SiO 2 ) prepared by sol-gel method was as photocatalyst in the degradation of β-naphthol in water under UV-illumination. The prepared sample has been characterized by powder X-ray diffraction (XRD), infrared spectroscopy (IR) and scanning electron microscopy (SEM). The supported catalyst had large surface area and good sedimentation ability. The photodegradation rate of β-naphthol under UV-irradiation depended strongly on adsorption capacity of the catalyst, and the photoactivity of the supported catalyst was much higher than that of the pure titanium dioxides. The experiments were measured by high performance liquid chromatography (HPLC). The photodegradation rate of β-naphthol using 60% TiO 2 -SiO 2 particles was faster than that using TiO 2 'Degussa P-25', TiO 2 'PC-50' and TiO 2 'Aldrich' as photocatalyst by 2.7, 4 and 7.8 times, respectively. The kinetics of photocatalytic β-naphthol degradation was found to follow a pseudo-first-order rate law. The effect of the TiO 2 loading on the photoactivity of TiO 2 -SiO 2 particles was also discussed. With good photocatalytic activity under UV-irradiation and the ability to be readily separated from the reaction system, this novel kind of catalyst exhibited the potential effective in the treatment of organic pollutants in aqueous systems.

POLIMERIZACIÓN ESTEREOSELECTIVA DE ESTIRENO CON PRECURSORES CATALÍTICOS DE CpTiCl3 e IndTiCl3

Directory of Open Access Journals (Sweden)

Alexander Contreras

2008-02-01

Full Text Available En este trabajo se realizaron reacciones de polimerización estereoselectiva de estireno con los precursores catalíticos( 5-ciclopentadienil-triclorotitanio [1] e (5-indenil-triclorotitanio [2] utilizando polimetilaluminoxano (MAO como cocatalizador. Se encontró que la polimerización de 1/MAO sólo requiere de relaciones de Al/Ti de 3500 con una actividad de 1,31 x 107g/mol2.h a 50 °C (diez veces superior a la conocida hasta el momento disminuyendo la cantidad de cocatalizador, precursor catalítico y tiempo de reacción. La polimerización de 2/MAO presenta una mayor actividad (1,9 x 107g/mol2.h y estereoselectividad (96,8% sindiotáctico que 1/MAO en las mismas condiciones de polimerización y alcanzando un valor máximo de 3,5 x 107 (g/mol2h a valores Al/Ti de 4000. El poliestireno sindiotáctico obtenido en estas reacciones fue caracterizado completamente por IR, DSC solubilidad y pesomolecular por viscosimetría.

Characteristics of laser clad α-Ti/TiC+(Ti,W)C1-x/Ti2SC+TiS composite coatings on TA2 titanium alloy

Science.gov (United States)

Zhai, Yong-Jie; Liu, Xiu-Bo; Qiao, Shi-Jie; Wang, Ming-Di; Lu, Xiao-Long; Wang, Yong-Guang; Chen, Yao; Ying, Li-Xia

2017-03-01

TiC reinforced Ti matrix composite coating with Ti2SC/TiS lubricant phases in-situ synthesized were prepared on TA2 titanium alloy by laser cladding with different powder mixtures: 40%Ti-19.5%TiC-40.5%WS2, 40%Ti-25.2%TiC-34.8%WS2, 40%Ti-29.4%TiC-30.6%WS2 (wt%). The phase compositions, microstructure, microhardness and tribological behaviors and wear mechanisms of coatings were investigated systematically. Results indicate that the main phase compositions of three coatings are all continuous matrix α-Ti, reinforced phases of (Ti,W)C1-x and TiC, lubricant phases of Ti2SC and TiS. The microhardness of the three different coatings are 927.1 HV0.5, 1007.5 HV0.5 and 1052.3 HV0.5, respectively. Compared with the TA2 titanium alloy (approximately 180 HV0.5), the microhardness of coatings have been improved dramatically. The coefficients of friction and the wear rates of those coatings are 0.41 and 30.98×10-5 mm3 N-1 m-1, 0.30 and 18.92×10-5 mm3 N-1 m-1, 0.34 and 15.98×10-5 mm3 N-1 m-1, respectively. Comparatively speaking, the coating fabricated with the powder mixtures of 40%Ti-25.2%TiC-34.8%WS2 presents superior friction reduction and anti-wear properties and the main wear mechanisms of that are slight plastic deformation and adhesive wear.

Nanoparticles of the giant dielectric material, CaCu3Ti4O12 from a precursor route

OpenAIRE

Thomas, P.; Dwarakanath, K.; Varma, K. B. R.; Kutty, T. R. N.

2013-01-01

A method of preparing the nanoparticles of CaCu3Ti4O12 (CCTO) with the crystallite size varying from 30 to 200 nm is optimized at a temperature as low as 680 1C from the exothermic thermal decomposition of an oxalate precursor, CaCu3(TiO)4(C2O4)8 ? 9H2O. The phase singularity of the complex oxalate precursor is confirmed by the wet chemical analyses, X-ray diffraction, FT-IR and TGA,DTA analyses. The UV Vis reflectance and ESR spectra of CCTO powders indicate that the Cu(II) coordination chan...

Carbon and TiO_2 synergistic effect on methylene blue adsorption

International Nuclear Information System (INIS)

Simonetti, Evelyn Alves Nunes; Simone Cividanes, Luciana de; Campos, Tiago Moreira Bastos; Rossi Canuto de Menezes, Beatriz; Brito, Felipe Sales; Thim, Gilmar Patrocínio

2016-01-01

Due to its high efficiency, low cost and a simple operation, the adsorption process is an important and widely used technique for industrial wastewater treatment. Recent studies on the removal of artificial dyes by adsorption include a large number of adsorbents, such as: activated carbon, silicates, carbon nanotube, graphene, fibers, titanates and doped titanates. The carbon insertion in the TiO_2 structure promotes a synergistic effect on the adsorbent composite, improving the adsorption and the charge-transfer efficiency rates. However, there are few studies regarding the adsorption capacity of TiO_2/Carbon composites with the carbon concentration. This study evaluates the effect of carbon (resorcinol/formaldehyde) insertion on TiO_2 structure through the adsorption process. Adsorbents were prepared by varying the carbon weight percentages using the sol-gel method. The physicochemical properties of the catalysts prepared, such as crystallinity, particle size, surface morphology, specific surface area and pore volume were investigated. The kinetic study, adsorption isotherm, pH effect and thermodynamic study were examined in batch experiments using methylene blue as organic molecule. In addition, the effect of carbon phase on the adsorption capacity of TiO_2-carbon composite was deeply investigated. SEM micrographs showed that TiO_2 phase grows along the carbon phase and FT-IR results showed the presence of Ti−O−C chemical bonding. The experiments indicate that the carbon phase acted as a nucleation agent for the growth of TiO_2 during the sol-gel step, with a TiO_2 structure suitable for blue methylene adsorption, resulting in a material with large surface area and slit-like or wedge-shaped pores. Further experiments will show the best carbon concentration for methylene blue adsorption using a TiO_2 based material. - Highlights: • This article deals with the adsorption of methylene blue onto TiO_2-Carbon composite. • The sol-gel synthesis was efficient

Formation and growth mechanism of TiC crystal in TiCp/Ti composites

Institute of Scientific and Technical Information of China (English)

金云学; 王宏伟; 曾松岩; 张二林

2002-01-01

Ti-C and Ti-Al-C alloys were prepared using gravity and directional solidification processes. Morphologies of TiC crystal were investigated by using SEM, XRD and EDX. Also, the formation and growth mechanism of TiC crystal have been analyzed on the basis of coordination polyhedron growth unit theory. During solidification of titanium alloys, the coordination polyhedron growth unit is TiC6. TiC6 growth units stack in a linking mode of edge to edge and form octahedral TiC crystal with {111} planes as present faces. Although the growing geometry of TiC crystal is decided by its lattice structure, the final morphology of TiC crystal depends on the effects of its growth environment. In solute concentration distribution, the super-saturation of C or TiC6 at the corners of octahedral TiC crystal is much higher than that of edges and faces of octahedral TiC crystal. At these corners the driving force for crystal growth is greater and the interface is instable which contribute to quick stacking rate of growth units at these corners and result in secondary dendrite arms along TiC crystallographic 〈100〉 directions. TiC crystal finally grows to be dendrites.

IR-based spot weld NDT in automotive applications

Science.gov (United States)

Chen, Jian; Feng, Zhili

2015-05-01

Today's auto industry primarily relies on destructive teardown evaluation to ensure the quality of the resistance spot welds (RSWs) due to their criticality in crash resistance and performance of vehicles. The destructive teardown evaluation is labor intensive and costly. The very nature of the destructive test means only a few selected welds will be sampled for quality. Most of the welds in a car are never checked. There are significant costs and risks associated with reworking and scrapping the defective welded parts made between the teardown tests. IR thermography as a non-destructive testing (NDT) tool has its distinct advantage — its non-intrusive and non-contact nature. This makes the IR based NDT especially attractive for the highly automated assembly lines. IR for weld quality inspection has been explored in the past, mostly limited to the offline post-processing manner in a laboratory environment. No online real-time RSW inspection using IR thermography has been reported. Typically for postprocessing inspection, a short-pulse heating via xenon flash lamp light (in a few milliseconds) is applied to the surface of a spot weld. However, applications in the auto industry have been unsuccessful, largely due to a critical drawback that cannot be implemented in the high-volume production line - the prerequisite of painting the weld surface to eliminate surface reflection and other environmental interference. This is due to the low signal-to-noise ratio resulting from the low/unknown surface emissivity and the very small temperature changes (typically on the order of 0.1°C) induced by the flash lamp method. An integrated approach consisting of innovations in both data analysis algorithms and hardware apparatus that effectively solved the key technical barriers for IR NDT. The system can be used for both real-time (during welding) and post-processing inspections (after welds have been made). First, we developed a special IR thermal image processing method that

More cloud for TiU

Directory of Open Access Journals (Sweden)

Marc van den Berg

2012-03-01

Full Text Available After a long period of developing library systems in house, Tilburg University (TiU decided to buy a new integrated library system (ILS and at the same time go for a cloud solution. Functionality, cost and vision of the future of scholarly communication were weighed up, and OCLC came out as the winner: TiU is now implementing OCLC’s ‘Web-scale Management Services’ (WMS and WorldCat Local (WCL. The road leading to that decision is described and some issues to be resolved are mentioned. The implementation project is intended to end in June 2012. Additionally, a short description is given of a possible future Dutch national information infrastructure for scholarly output that consists of just four major building blocks which partly already exist.

Fabrication and characterization of perovskite-type solar cells with Nb-doped TiO{sub 2} layers

Energy Technology Data Exchange (ETDEWEB)

Saito, Jo; Oku, Takeo, E-mail: oku@mat.usp.ac.jp; Suzuki, Atsushi; Akiyama, Tsuyoshi [The University of Shiga Prefecture, Hikone, Shiga 522-8533 (Japan)

2016-02-01

Organic-inorganic hybrid heterojunction solar cells containing perovskite CH{sub 3}NH{sub 3}PbI{sub 3} using Nb-doped TiO{sub 2} as an electron-transporting layer were fabricated and characterized. Nb-doped TiO{sub 2} layer showed an improvement of the short-circuit current density and power conversion efficiency using Ti{sub 0.95}Nb{sub 0.05}O{sub 2}.

Methylene blue photocatalytic mineralization under visible irradiation on TiO{sub 2} thin films doped with chromium

Energy Technology Data Exchange (ETDEWEB)

Diaz-Uribe, Carlos; Vallejo, William, E-mail: williamvallejo@mail.uniatlantico.edu.co; Ramos, Wilkendry

2014-11-15

Graphical abstract: - Highlights: • We used an easy and inexpensive technique to dope thin films of TiO{sub 2}. • We proved that hydroxyl radicals were generated under visible light irradiation by Cr:TiO{sub 2}. • We used a Haber–Weiss reaction through Cr:TiO{sub 2} catalyst to improve the photo-mineralization process. - Abstract: We studied changes in structural, optical and photocatalytic properties of TiO{sub 2} thin films due to doping process with chromium. Powders of undoped TiO{sub 2} and chromium-doped TiO{sub 2} (Cr:TiO{sub 2}) were synthesized by sol–gel method and, thin films were deposited by doctor blade method. The properties of the thin films were studied by X-ray diffraction (XRD), infrared spectroscopy (IR) and diffuse reflectance. The XRD patterns indicated that doping process changed the crystalline phases radio of TiO{sub 2} thin films, furthermore, the optical analysis showed that band gap value of Cr:TiO{sub 2} thin films was 31% fewer than undoped TiO{sub 2} thin films. Along, Langmuir–Hinshelwood model was used to obtain kinetic information of the photo-mineralization process; results indicated that photocatalytic activity of Cr:TiO{sub 2} thin films were four times better than undoped TiO{sub 2} thin films; finally the synergic effect was tested by addition of the H{sub 2}O{sub 2}, photocatalytic yield was improved from 26% to 61% when methylene blue photo-mineralization was assisted with slightly amount of H{sub 2}O{sub 2}.

Development of Perovskite Sensitized Thin Film Solar Cells Based on Graphene Oxide/TiO2 Photoanodes

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Momina KHANNAM

2017-03-01

Full Text Available Graphene oxide/TiO2(GO/TiO2 nanocomposites with different concentrations of GO were prepared by a self-assemble method. The synthesized GO/TiO2 nanocomposites are characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, and transmission electron microscopic (TEM analysis. Using these GO/TiO2 nanocomposites as an electron collection layer a series of solid state perovskite sensitized solar cells were fabricated. The photovoltaic properties like short circuit current density and photo conversion efficiency of the fabricated device were evaluated. It was noticed that the nanocomposites has significant effects on the photovoltaic properties of the device. With increase in the amount of GO in the nanocomposites the short circuit current density of the devices increased from 1.79 to 4.65 mAcm-2 and the photo conversion efficiency increased from 0.413 to 1.34 %.

Flow-Regulated Growth of Titanium Dioxide (TiO2 ) Nanotubes in Microfluidics.

Science.gov (United States)

Fan, Rong; Chen, Xinye; Wang, Zihao; Custer, David; Wan, Jiandi

2017-08-01

Electrochemical anodization of titanium (Ti) in a static, bulk condition is used widely to fabricate self-organized TiO 2 nanotube arrays. Such bulk approaches, however, require extended anodization times to obtain long TiO 2 nanotubes and produce only vertically aligned nanotubes. To date, it remains challenging to develop effective strategies to grow long TiO 2 nanotubes in a short period of time, and to control the nanotube orientation. Here, it is shown that the anodic growth of TiO 2 nanotubes is significantly enhanced (≈16-20 times faster) under flow conditions in microfluidics. Flow not only controls the diameter, length, and crystal orientations of TiO 2 nanotubes, but also regulates the spatial distribution of nanotubes inside microfluidic devices. Strikingly, when a Ti thin film is deposited on silicon substrates and anodized in microfluidics, both vertically and horizontally aligned (relative to the bottom substrate) TiO 2 nanotubes can be produced. The results demonstrate previously unidentified roles of flow in the regulation of growth of TiO 2 nanotubes, and provide powerful approaches to effectively grow long, oriented TiO 2 nanotubes, and construct hierarchical TiO 2 nanotube arrays on silicon-based materials. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Y-doping TiO2 nanorod arrays for efficient perovskite solar cells

Science.gov (United States)

Deng, Xinlian; Wang, Yanqing; Cui, Zhendong; Li, Long; Shi, Chengwu

2018-05-01

To improve the electron transportation in TiO2 nanorod arrays and charge separation in the interface of TiO2/perovskite, Y-doping TiO2 nanorod arrays with the length of 200 nm, diameter of 11 nm and areal density of 1050 μm-2 were successfully prepared by the hydrothermal method and the influence of Y/Ti molar ratios of 0%, 3%, 5% in the hydrothermal grown solutions on the growth of TiO2 nanorod arrays was investigated. The results revealed that the appropriate Y/Ti molar ratios can increase the areal density of the corresponding TiO2 nanorod arrays and improve the charge separation in the interface of the TiO2/perovskite. The Y-doping TiO2 nanorod array perovskite solar cells with the Y/Ti molar ratio of 3% exhibited a photoelectric conversion efficiency (PCE) of 18.11% along with an open-circuit voltage (Voc) of 1.06 V, short-circuit photocurrent density (Jsc) of 22.50 mA cm-2 and fill factor (FF) of 76.16%, while the un-doping TiO2 nanorod array perovskite solar cells gave a PCE of 16.42% along with Voc of 1.04 V, Jsc of 21.66 mA cm-2 and FF of 72.97%.

Protoide šaknis *leh3u – "lietis, tekėti..." baltų kalbose (liet. liūtìs ir lietùs

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Simas Karaliūnas

2011-10-01

Full Text Available THE PROTOIDE. ROOT *leh3u- “flow, stream, pour...” IN BALTIC (LITH. liūtìs “heavy shower, downpour” AND lietùs “rain” Summary The relationship of Lith. liū́tis/liūtìs “heavy shower, downpour” and lietùs “rain”, as has been suggested by P. Skardžius, may be understood only in the Protoindoeuropean prospect. Hit. lahui “it flows, streams, pours...”, Gr. λoύει “he bathes, washes” and Lat. lavit “id.” seem to have the apophonic o and their protoform should be reconstructed as *leh3-e/o, as proposed by F. Bader. Its root vocalism e is attested in Mycenaean Gr. re-wo-te-re-jo and Lith. liaũkti (-ia “flow, stream” <* leu(k-. Lith. liū́tis/liūtìs with suffix -ti- rests on the allomorph *lh3u- of this protoIE. root, attested, for instance, in Hit. li-lhuu̯ai- , le-lhuu̯ai- and possibly in Lat. perfect lāvī, if from *lh3u-ai. A verbal form * (apa-lh3u- [cf. Lat. ab-luō, Gr. άπο-λούω, Hit. appa(n lahhu-] might have served as a basis for derivatives Lith. pa-liū́tis, pa-liū́tė “long and heavy rain, a period of rains”. The palatalized l'< *li̯ of liū́tis, pa-liū́tis and pa-liū́tė attaches to the vocalism e form * leh3u ->* leu(k-> *liau(k-. With respect to their prefixal derivation the lake name Lith. At-lavas and Lat. ab-luvium, dī-luvium etc. “effusion, overflow, inundation, deluge” may be also compared and their root morpheme *-loui̯o- with the lake name Lith. Laujà identified. Due to structural analogy (:* leh3-u - there might have existed a parallel form * leh3-i- conserved in Lith. líeti (praes. líeja, lẽja, praet. líejo, lė́jo ”pour“ and Latv. liêt (praes. leju, praet. lêju “id.”, from which Lith. lietús “rain”, Latv. liêtus “id.” are derived with suffix -tu-.

In vitro and in vivo performance of bioactive Ti6Al4V/TiC/HA implants fabricated by a rapid microwave sintering technique

International Nuclear Information System (INIS)

Choy, Man Tik; Tang, Chak Yin; Chen, Ling; Wong, Chi Tak; Tsui, Chi Pong

2014-01-01

Failure of the bone–implant interface in a joint prosthesis is a main cause of implant loosening. The introduction of a bioactive substance, hydroxyapatite (HA), to a metallic bone–implant may enhance its fixation on human bone by encouraging direct bone bonding. Ti6Al4V/TiC/HA composites with a reproducible porous structure (porosity of 27% and pore size of 6–89 μm) were successfully fabricated by a rapid microwave sintering technique. This method allows the biocomposites to be fabricated in a short period of time under ambient conditions. Ti6Al4V/TiC/HA composites exhibited a compressive strength of 93 MPa, compressive modulus of 2.9 GPa and microhardness of 556 HV which are close to those of the human cortical bone. The in vitro preosteoblast MC3T3-E1 cells cultured on the Ti6Al4V/TiC/HA composite showed that the composite surface could provide a biocompatible environment for cell adhesion, proliferation and differentiation without any cytotoxic effects. This is among the first attempts to study the in vivo performance of load-bearing Ti6Al4V/TiC and Ti6Al4V/TiC/HA composites in a live rabbit. The results indicated that the Ti6Al4V/TiC/HA composite had a better bone–implant interface compared with the Ti6Al4V/TiC implant. Based on the microstructural features, the mechanical properties, and the in vitro and in vivo test results from this study, the Ti6Al4V/TiC/HA composites have the potential to be employed in load-bearing orthopedic applications. - Highlights: • Ti6Al4V/TiC and Ti6Al4V/TiC/HA composites were fabricated by microwave sintering. • Ti6Al4V/TiC/HA exhibited mechanical properties close to human cortical bone. • Ti6Al4V/TiC/HA could provide a biocompatible environment for bone cell growth. • Ti6Al4V/TiC/HA showed a better bone–implant interface than Ti6Al4V/TiC. • Ti6Al4V/TiC/HA could be used for bone replacement under load-bearing conditions

Mesoporous TiO2 Micro-Nanometer Composite Structure: Synthesis, Optoelectric Properties, and Photocatalytic Selectivity

Directory of Open Access Journals (Sweden)

Kun Liu

2012-01-01

Full Text Available Mesoporous anatase TiO2 micro-nanometer composite structure was synthesized by solvothermal method at 180°C, followed by calcination at 400°C for 2 h. The as-prepared TiO2 was characterized by X-ray diffraction (XRD, scanning electron microscope (SEM, transmission electron microscope (TEM, and Fourier transform infrared spectrum (FT-IR. The specific surface area and pore size distribution were obtained from N2 adsorption-desorption isotherm, and the optoelectric property of the mesoporous TiO2 was studied by UV-Vis absorption spectrum and surface photovoltage spectra (SPS. The photocatalytic activity was evaluated by photodegradation of sole rhodamine B (RhB and sole phenol aqueous solutions under simulated sunlight irradiation and compared with that of Degussa P-25 (P25 under the same conditions. The photodegradation preference of this mesoporous TiO2 was also investigated for an RhB-phenol mixed solution. The results show that the TiO2 composite structure consists of microspheres (∼0.5–2 μm in diameter and irregular aggregates (several hundred nanometers with rough surfaces and the average primary particle size is 10.2 nm. The photodegradation activities of this mesoporous TiO2 on both RhB and phenol solutions are higher than those of P25. Moreover, this as-prepared TiO2 exhibits photodegradation preference on RhB in the RhB-phenol mixture solution.

Photocatalytic and microwave absorbing properties of polypyrrole/Fe-doped TiO2 composite by in situ polymerization method

International Nuclear Information System (INIS)

Li Qiaoling; Zhang Cunrui; Li Jianqiang

2011-01-01

Research highlights: → Polypyrrole/Fe-doped TiO 2 composite is prepared by in situ polymerization of pyrrole on the Fe-doped TiO 2 template. → The Fe-doped TiO 2 microbelts are prepared by sol-gel method using the absorbent cotton template for the first time. → Then the Fe-doped TiO 2 microbelts are used as template for the preparation of polypyrrole/Fe-doped TiO 2 composites. → The structure, morphology and properties of the composites are characterized with scanning electron microscope (SEM), IR, Net-work Analyzer. → A possible formation mechanism of Fe-doped TiO 2 microbelts and polypyrrole/Fe-doped TiO 2 composites has been proposed. → The effect of the mol ratio of pyrrole/Fe-doped TiO 2 on the photocatalysis properties and microwave loss properties of the composites is investigated. - Abstract: The Fe-doped TiO 2 microbelts were prepared by sol-gel method using the absorbent cotton template for the first time. Then the Fe-doped TiO 2 microbelts were used as templates for the preparation of polypyrrole/Fe-doped TiO 2 composites. Polypyrrole/Fe-doped TiO 2 composites were prepared by in situ polymerization of pyrrole on the Fe-doped TiO 2 template. The structure, morphology and properties of the composites were characterized with scanning electron microscope (SEM), FTIR, Net-work Analyzer. The possible formation mechanisms of Fe-doped TiO 2 microbelts and polypyrrole/Fe-doped TiO 2 composites have been proposed. The effect of the molar ratio of pyrrole/Fe-doped TiO 2 on the photocatalytic properties and microwave loss properties of the composites was investigated.

Structural evolution of Ti/TiC multilayers

International Nuclear Information System (INIS)

Dahan, I.; Frage, N.; Dariel, M.P.

2004-01-01

Hard coatings based on metal/ceramic multilayers with periods in the nanometer range have been shown to possess some potential for improved tribological and mechanical properties. The present work is concerned with the structural evolution of (Ti/TiC) multilayers. Two kinds of multilayers consisting of 30 equithick (40 nm)TiC layers and 20 and 60 nm thick Ti layers, respectively, were sputter deposited on Mo substrates. The structural and the compositional evolution of these multilayers were examined by x-ray diffraction, transition electron microscopy (TEM), high-resolution TEM, Auger electron microscopy spectroscopy and differential thermal analysis (DTA), in the as-deposited state and after various heat treatments up to 500 deg. C. Initially, the Ti layers had a crystalline columnar grain structure displaying a (002) texture. The TiC layers displayed weak crystallinity with a pronounced (111) texture. In the course of the heat treatments, carbon diffused from the carbide layer into the adjacent Ti layers transforming the latter into off-stoichiometric TiC x with x≅0.5 and simultaneously depleting the carbon content of the initial carbide layer. The formed TiC x layers maintained the textural relationship with the neighboring TiC layers, consistent with a transformation that involved only a ABAB to ABC stacking change of the Ti sublattice. Increased mobility of the Ti atoms in carbon-depleted original TiC layers led to their full or partial recrystallization. The thermal effects associated both with the transformation of Ti layers into TiC, due to the influx of carbon atoms, and with the recrystallization of the original TiC layers were clearly revealed by the DTA measurements

Deposition and characterisation of multilayer hard coatings. Ti/TiNδ/TiCxNy/(TiC) a-C:H/(Ti) a-C:H

International Nuclear Information System (INIS)

Burinprakhon, T.

2001-02-01

Multilayer hard coatings containing Ti, TiNδ, TiC x N y , (TiC m ) a-C:H, (TiC n ) a-C:H, and (Ti) a-C:H were deposited on commercially pure titanium substrates by using an asymmetric bipolar pulsed-dc reactive magnetron sputtering of a titanium target, with Ar, Ar+N 2 , Ar+N 2 +CH 4 , and Ar+CH 4 gas mixtures. The microstructures, elemental compositions and bonding states of the interlayers and the coating surfaces were studied by using cross-sectional transmission electron microscopy (XTEM), electron energy loss spectroscopy (EELS), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The microstructure development of the multilayer coating was strongly influenced by target poisoning. As a result of the complete poisoning of the titanium target during the deposition of TiNδ and TiC x N y interlayers, the a-C:H interlayers containing graded titanium and nitrogen contents were found to develop successively to the TiC x N y interlayer without the formation of near-stoichiometric TiC. The (TiC m ) a-C:H interlayer consisted of nano-particles of distorted fcc crystal structure embedded in the a-C:H matrix. The (TiC n ) a-C:H and (Ti) a-C:H top layers were found to be a-C:H matrix without nano-particles. In the (Ti) a-C:H top layer there was no measurable amount of Ti observed, regardless of the variation of CH 4 concentration between 37.5 and 60 % flow rate in Ar+-CH4 gas mixture. The top layer (Ti) a-C:H was found to contain approximately 10 atomic % nitrogen, due to N 2 contamination during deposition caused by low conductance of N 2 through the nominally closed valve of the mass flow controller. The change of the CH 4 concentration during deposition of the top layer (Ti) a-C:H, however, showed a strong influence on the hydrogen content. The comparison of the fluorescence background of the Raman spectra revealed that hydrogen-less (Ti) a-C:H was deposited at a CH 4 concentration of less than 50 % flow rate in Ar. The hardness

Fabrication and characterization of laminated Ti-(TiB+La2O3/Ti composite

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Yuanfei Han

2015-10-01

Full Text Available The incorporation of ceramic particulate reinforcements into titanium alloys can improve the specific strength and specific stiffness, while inevitably reduce the plasticity and ductility. In this study, in situ synthesized multilayer Ti-(TiB+La2O3/Ti composite was designed by learning from the microstructure of nature biological materials with excellent mechanical properties. The Ti-(TiB+La2O3/Ti composite with unique characteristic of laminated structure was prepared by combined powder metallurgy and hot rolling. The method has the synthesize advantages with in-situ reaction of Ti and LaB6 at high temperature and controllability of reinforcements size and constituent phases in composites. The result shows that the pores in the as sintered laminated structure composite completely disappeared after hot rolling at 1050 °C. The agglomerated reinforcement particles were well dispersed and distributed uniformly along the rolling direction. The thickness of pure Ti layer and (TiB+La2O3/Ti composite layer decreased from 1 mm to about 200 μm. Meanwhile, the grains size was refined obviously after rolling deformation. The room temperature tensile test indicates that the elongation of the laminated Ti-(TiB+La2O3/Ti composite improved from 13% to 17% in comparison with the uniform (TiB+La2O3/Ti composite, while the tensile strength had little change. It provides theoretical and experimental basis for fabricating the novel high performance laminated Ti-(TiB+La2O3/Ti composites.

Defective TiO2 with oxygen vacancies: synthesis, properties and photocatalytic applications

Science.gov (United States)

Pan, Xiaoyang; Yang, Min-Quan; Fu, Xianzhi; Zhang, Nan; Xu, Yi-Jun

2013-04-01

Titanium dioxide (TiO2), as an important semiconductor metal oxide, has been widely investigated in the field of photocatalysis. The properties of TiO2, including its light absorption, charge transport and surface adsorption, are closely related to its defect disorder, which in turn plays a significant role in the photocatalytic performance of TiO2. Among all the defects identified in TiO2, oxygen vacancy is one of the most important and is supposed to be the prevalent defect in many metal oxides, which has been widely investigated both by theoretical calculations and experimental characterizations. Here, we give a short review on the existing strategies for the synthesis of defective TiO2 with oxygen vacancies, and the defect related properties of TiO2 including structural, electronic, optical, dissociative adsorption and reductive properties, which are intimately related to the photocatalytic performance of TiO2. In particular, photocatalytic applications with regard to defective TiO2 are outlined. In addition, we offer some perspectives on the challenge and new direction for future research in this field. We hope that this tutorial minireview would provide some useful contribution to the future design and fabrication of defective semiconductor-based nanomaterials for diverse photocatalytic applications.Titanium dioxide (TiO2), as an important semiconductor metal oxide, has been widely investigated in the field of photocatalysis. The properties of TiO2, including its light absorption, charge transport and surface adsorption, are closely related to its defect disorder, which in turn plays a significant role in the photocatalytic performance of TiO2. Among all the defects identified in TiO2, oxygen vacancy is one of the most important and is supposed to be the prevalent defect in many metal oxides, which has been widely investigated both by theoretical calculations and experimental characterizations. Here, we give a short review on the existing strategies for the

TES arrays for the short wavelength band of the SAFARI instrument on SPICA

Science.gov (United States)

Khosropanah, P.; Hijmering, R.; Ridder, M.; Gao, J. R.; Morozov, D.; Mauskopf, P. D.; Trappe, N.; O'Sullivan, C.; Murphy, A.; Griffin, D.; Goldie, D.; Glowacka, D.; Withington, S.; Jackson, B. D.; Audley, M. D.; de Lange, G.

2012-09-01

SPICA is an infra-red (IR) telescope with a cryogenically cooled mirror (~5K) with three instruments on board, one of which is SAFARI that is an imaging Fourier Transform Spectrometer (FTS) with three bands covering the wavelength of 34-210 μm. We develop transition edge sensors (TES) array for short wavelength band (34-60 μm) of SAFARI. These are based on superconducting Ti/Au bilayer as TES bolometers with a Tc of about 105 mK and thin Ta film as IR absorbers on suspended silicon nitride (SiN) membranes. These membranes are supported by long and narrow SiN legs that act as weak thermal links between the TES and the bath. Previously an electrical noise equivalent power (NEP) of 4×10-19 W/√Hz was achieved for a single pixel of such detectors. As an intermediate step toward a full-size SAFARI array (43×43), we fabricated several 8×9 detector arrays. Here we describe the design and the outcome of the dark and optical tests of several of these devices. We achieved high yield (<93%) and high uniformity in terms of critical temperature (<5%) and normal resistance (7%) across the arrays. The measured dark NEPs are as low as 5×10-19 W/√Hz with a response time of about 1.4 ms at preferred operating bias point. The optical coupling is implemented using pyramidal horns array on the top and hemispherical cavity behind the chip that gives a measured total optical coupling efficiency of 30±7%.

In situ NiTi/Nb(Ti) composite

International Nuclear Information System (INIS)

Jiang, Daqiang; Cui, Lishan; Jiang, Jiang; Zheng, Yanjun

2013-01-01

Graphical abstract: - Highlights: • In situ NiTi/Nb(Ti) composites were fabricated. • The transformation temperature was affected by the mixing Ti:Ni atomic ratios. • The NiTi component became micron-scale lamella after forging and rolling. • The composite exhibited high strength and high damping capacity. - Abstract: This paper reports on the creation of a series of in situ NiTi/Nb(Ti) composites with controllable transformation temperatures based on the pseudo-binary hypereutectic transformation of NiTi–Nb system. The composite constituent morphology was controlled by forging and rolling. It is found that the thickness of the NiTi lamella in the composite reached micron level after the hot-forging and cold-rolling. The NiTi/Nb(Ti) composite exhibited high damping capacity as well as high yield strength

Suppression of superconductivity in Nb by IrMn in IrMn/Nb bilayers

KAUST Repository

Wu, B. L.

2013-10-10

Effect of antiferromagnet on superconductivity has been investigated in IrMn/Nb bilayers. Significant suppression of both transition temperature (Tc) and lower critical field (Hc1) of Nb is found in IrMn/Nb bilayers as compared to a single layer Nb of same thickness; the suppression effect is even stronger than that of a ferromagnet in NiFe/Nb bilayers. The addition of an insulating MgO layer at the IrMn-Nb interface nearly restores Tc to that of the single layer Nb, but Hc1 still remains suppressed. These results suggest that, in addition to proximity effect and magnetic impurity scattering, magnetostatic interaction also plays a role in suppressing superconductivity of Nb in IrMn/Nb bilayers. In addition to reduced Tc and Hc1, the IrMn layer also induces broadening in the transition temperature of Nb, which can be accounted for by a finite distribution of stray field from IrMn.

Pt(II) porphyrin modified TiO{sub 2} composites as photocatalysts for efficient 4-NP degradation

Energy Technology Data Exchange (ETDEWEB)

Mingyue, Duan [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xian, Shaanxi 710069 (China); Li Jun, E-mail: junli@nwu.edu.cn [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xian, Shaanxi 710069 (China); Min, Li [Datang Wujiang Gas Turbine Power Limited Liability Company, Jiangsu 215214 (China); Zengqi, Zhang; Chen, Wang [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xian, Shaanxi 710069 (China)

2012-05-01

Three Pt(II) porphyrins 5,10,15,20-tetra-[2 or 3 or 4-(3-phenoxy)propoxy]phenyl porphyrin]platinum(II) (1-3) were synthesized and characterized spectroscopically. The corresponding Pt(II) porphyrins-TiO{sub 2} composites were then prepared and characterized by means of FT-IR and diffused reflectance spectra, X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity of Pt(II) porphyrins-TiO{sub 2} catalyst was investigated by testing the photodegradation of 4-nitrophenol (4-NP) in aqueous solution under irradiation with Xenon lamp. The results indicated that Pt(II) porphyrins greatly enhanced the photocatalytic efficiency of bare TiO{sub 2} in photodegrading the 4-NP, and the distinct space tropisms of peripheral substituents in meso-sites of porphyrin ring led to different results.

Microstructure and corrosion resistance of TC2 Ti alloy by laser cladding with Ti/TiC/TiB{sub 2} powders

Energy Technology Data Exchange (ETDEWEB)

Diao, Yunhua, E-mail: 990722012@qq.com; Zhang, Kemin, E-mail: zhangkm@sues.edu.cn

2015-10-15

Highlights: • A TiC/TiB{sub 2} composite coating was produced onto a TC2 Ti alloy by laser cladding with Ti/TiC/TiB{sub 2} powders. • A maximum hardness of 1100 HV was achieved in the laser clad TiC/TiB{sub 2} composite layer. • Corrosion resistance of the TC2 alloy in NaCl (3.5 wt%) aqueous solution can be improved after laser cladding. - Abstract: In the present work, a TiC/TiB{sub 2} composite coating was produced onto a TC2 Ti alloy by laser cladding with Ti/TiC/TiB{sub 2} powders. The surface microstructure, phase components and compositions were characterized with methods of optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffractometry (XRD), and energy dispersive spectrometry (EDS). The cladding layer is consisted of Ti, TiC and TiB{sub 2}. And the surface microhardness was measured. After laser cladding, a maximum hardness of 1100 HV is achieved in the laser cladding surface layer, which is more three times higher than that of the TC2 substrate (∼300 HV). Due to the formation of TiC and TiB{sub 2} intermetallic compounds in the alloyed region and grain refinement, the microhardness of coating is higher than TC2 Ti alloy. In this paper, the corrosion property of matrix material and treated samples were both measured in NaCl (3.5 wt%) aqueous solution. From the result we can see that the laser cladding specimens’ corrosion property is clearly becoming better than that of the substrate.

Effect of nano-CeO 2 on microstructure properties of TiC/TiN+TiCN ...

Indian Academy of Sciences (India)

TiC/TiN+TiCN-reinforced composite coatings were fabricated on Ti–6Al–4V alloy by laser cladding, which improved surface performance of the substrate. ... X-ray diffraction results indicated that Al3Ti+TiC/TiN+nano-CeO2 laser-cladded coating consisted of Ti3Al, TiC, TiN, Ti2Al20Ce, TiC0.3N0.7, Ce(CN)3 and CeO2, this ...

The effect of nano-TiO2 photocatalysis on the antioxidant activities of Cu, Zn-SOD at physiological pH.

Science.gov (United States)

Zheng, Wen; Zou, Hai-Feng; Lv, Shao-Wu; Lin, Yan-Hong; Wang, Min; Yan, Fei; Sheng, Ye; Song, Yan-Hua; Chen, Jie; Zheng, Ke-Yan

2017-09-01

Security issues of nanoparticles on biological toxicity and potential environmental risk have attracted more and more attention with the rapid development and wide applications of nanotechnology. In this work, we explored the effect and probable mechanism of nano-TiO 2 on antioxidant activity of copper, zinc superoxide dismutase (Cu, Zn-SOD) under natural light and mixed light at physiological pH. Nano-TiO 2 was prepared by sol-hydrothermal method, and then characterized by X-ray Diffraction (XRD) and Transmission electron micrographs (TEM). The Cu, Zn-SOD was purified by sephadex G75 chromatography and qualitatively analyzed by sodium dodecyl sulfate polypropylene amide gel electrophoresis (SDS-PAGE). The effect and mechanism were elucidated base on Fourier Transform Infrared Spectrometer (FT-IR), Circular Dichroism (CD), zeta potential, and electron spin resonance (ESR) methods. Accompanying the results of FT-IR, CD and zeta potential, it could be concluded that nano-TiO 2 had no effect on the antioxidant activity of Cu, Zn-SOD by comparing the relative activity under natural light at physiological pH. But the relative activity of Cu, Zn-SOD significantly decreased along with the increase of nano-TiO 2 concentration under the mixed light. The results of ESR showed the cause of this phenomenon was the Cu(II) in the active site of Cu, Zn-SOD was reduced to Cu(I) by H 2 O 2 and decreased the content of active Cu, Zn-SOD. The reduction can be inhibited by catalase. Excess O 2 ·- produced by nano-TiO 2 photocatalysis under mixed light accumulated a mass of H 2 O 2 through disproportionation reaction in this experimental condition. The results show that nano-TiO 2 cannot affect the antioxidant activity of Cu, Zn-SOD in daily life. The study on the effect of nano-TiO 2 on Cu, Zn-SOD will provide a valid theory support for biological safety and the toxicological effect mechanism of nanomaterials on enzyme. Copyright © 2017 Elsevier B.V. All rights reserved.

Towards the development of a novel bioinspired functional material: synthesis and characterization of hybrid TiO2/DHICA-melanin nanoparticles.

Science.gov (United States)

Pezzella, Alessandro; Capelli, Luigia; Costantini, Aniello; Luciani, Giuseppina; Tescione, Fabiana; Silvestri, Brigida; Vitiello, Giuseppe; Branda, Francesco

2013-01-01

A large number of recent literature data focus on modification/modulation of surface chemistry of inorganic materials in order to improve their functional properties. Melanins, a wide class of natural pigments, are recently emerging as a powerful organic component for developing bioinspired active material for a large number of applications from organoelectronics to bioactive compounds. Here we report the use of the approach referred as "chimie douce", involving in situ formation of the hybrids through reactions of precursors under mild conditions, to prepare novel hybrid functional architectures based on eumelanin like 5,6 dihydroxyindole-2-carboxylic acid (DHICA) polymer and TiO2. Two synthesis procedures were carried out to get DHICA-melanin coated TiO2 nanoparticles as well as mixed DHICA/TiO2 hybrid nanostructures. Such systems were characterized through EPR, FT-IR and fluorescence spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction (XRD), and TEM microscopy in order to assess the effect of synthesis path as well as of DHICA content on structural, morphological and optical properties of TiO2 nanostructures. In particular, EPR, FT-IR spectra and TGA analysis confirmed the presence of DHICA-melanin in these samples. TEM measurements indicated the formation of the nanoparticles having relatively narrow size distribution with average particle size of about 10nm. DHICA-melanin does act as a morphological agent affecting morphology of hybrid nanostructures. XRD analysis proved that TiO2 hybrid nanoparticles kept anatase structures for DHICA-melanin contents within the range of investigated compositions, i.e. up to 50% wt/wt. Copyright © 2012 Elsevier B.V. All rights reserved.

Preparation and characterizations of Ba0.8Ca0.2TiO3 by complex polymerization method (CPM)

International Nuclear Information System (INIS)

Motta, F.V.; Marques, A.P.A.; Escote, M.T.; Melo, D.M.A.; Ferreira, A.G.; Longo, E.; Leite, E.R.; Varela, J.A.

2008-01-01

Ba 0.8 Ca 0.2 TiO 3 (BCT) was prepared by the complex polymerization method (CPM) using Ba 0.8 Ca 0.2 CO 3 and [Ti[OCH(CH 3 ) 2 ] 4 as starting materials. The powders were crystallized at several temperatures from 400 to 1200 deg. C using different times (from 1 to 8 h). The phase evolution and the physical properties were characterized by X-ray diffraction, Raman and IR spectroscopy. Such results indicate that the precursor Ba 0.8 Ca 0.2 CO 3 used in the synthesis of Ba 0.8 Ca 0.2 TiO 3 promotes an effective complexation of the ions Ca 2+ in the matrix of BaTiO 3 . After heat treatment for 2 h at 600 deg. C the phase BCT was obtained with absence of the CaTiO 3 or BaCO 3 phases. The CPM is an efficient method in the synthesis of the BCT, using small reaction time and low temperature and cost for the preparation of these powders

Spin-Coating and Characterization of Multiferroic MFe2O4 (M=Co, Ni) / BaTiO3 Bilayers

Science.gov (United States)

Quandt, Norman; Roth, Robert; Syrowatka, Frank; Steimecke, Matthias; Ebbinghaus, Stefan G.

2016-01-01

Bilayer films of MFe2O4 (M=Co, Ni) and BaTiO3 were prepared by spin coating of N,N-dimethylformamide/acetic acid solutions on platinum coated silicon wafers. Five coating steps were applied to get the desired thickness of 150 nm for both the ferrite and perovskite layer. XRD, IR and Raman spectroscopy revealed the formation of phase-pure ferrite spinels and BaTiO3. Smooth surfaces with roughnesses in the order of 3 to 5 nm were found in AFM investigations. Saturation magnetization of 347 emu cm-3 for the CoFe2O4/BaTiO3 and 188 emu cm-3 for the NiFe2O4/BaTiO3 bilayer, respectively were found. For the CoFe2O4/BaTiO3 bilayer a strong magnetic anisotropy was observed with coercivity fields of 5.1 kOe and 3.3 kOe (applied magnetic field perpendicular and parallel to film surface), while for the NiFe2O4/BaTiO3 bilayer this effect is less pronounced. Saturated polarization hysteresis loops prove the presence of ferroelectricity in both systems.

Oriented epitaxial TiO2 nanowires for water splitting

Science.gov (United States)

Hou, Wenting; Cortez, Pablo; Wuhrer, Richard; Macartney, Sam; Bozhilov, Krassimir N.; Liu, Rong; Sheppard, Leigh R.; Kisailus, David

2017-06-01

Highly oriented epitaxial rutile titanium dioxide (TiO2) nanowire arrays have been hydrothermally grown on polycrystalline TiO2 templates with their orientation dependent on the underlying TiO2 grain. Both the diameter and areal density of the nanowires were tuned by controlling the precursor concentration, and the template surface energy and roughness. Nanowire tip sharpness was influenced by precursor solubility and diffusivity. A new secondary ion mass spectrometer technique has been developed to install additional nucleation sites in single crystal TiO2 templates and the effect on nanowire growth was probed. Using the acquired TiO2 nanowire synthesis knowhow, an assortment of nanowire arrays were installed upon the surface of undoped TiO2 photo-electrodes and assessed for their photo-electrochemical water splitting performance. The key result obtained was that the presence of short and dispersed nanowire arrays significantly improved the photocurrent when the illumination intensity was increased from 100 to 200 mW cm-2. This is attributed to the alignment of the homoepitaxially grown nanowires to the [001] direction, which provides the fastest charge transport in TiO2 and an improved pathway for photo-holes to find water molecules and undertake oxidation. This result lays a foundation for achieving efficient water splitting under conditions of concentrated solar illumination.

Highly Al-doped TiO2 nanoparticles produced by Ball Mill Method: structural and electronic characterization

International Nuclear Information System (INIS)

Santos, Desireé M. de los; Navas, Javier; Sánchez-Coronilla, Antonio; Alcántara, Rodrigo; Fernández-Lorenzo, Concha; Martín-Calleja, Joaquín

2015-01-01

Highlights: • Highly Al-doped TiO 2 nanoparticles were synthesized using a Ball Mill Method. • Al doping delayed anatase to rutile phase transformation. • Al doping allow controlling the structural and electronic properties of nanoparticles. - Abstract: This study presents an easy method for synthesizing highly doped TiO 2 nanoparticles. The Ball Mill method was used to synthesize pure and Al-doped titanium dioxide, with an atomic percentage up to 15.7 at.% Al/(Al + Ti). The samples were annealed at 773 K, 973 K and 1173 K, and characterized using ICP-AES, XRD, Raman spectroscopy, FT-IR, TG, STEM, XPS, and UV–vis spectroscopy. The effect of doping and the calcination temperature on the structure and properties of the nanoparticles were studied. The results show high levels of internal doping due to the substitution of Ti 4+ ions by Al 3+ in the TiO 2 lattice. Furthermore, anatase to rutile transformation occurs at higher temperatures when the percentage of doping increases. Therefore, Al doping allows us to control the structural and electronic properties of the nanoparticle synthesized. So, it is possible to obtain nanoparticles with anatase as predominant phase in a higher range of temperature

Assessment of Azithromycin in Pharmaceutical Formulation by Fourier-transform Infrared (FT-IR Transmission Spectroscopy

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Muhammad Ali Mallah

2011-12-01

Full Text Available A simple, rapid and economical method for azithromycin quantification in solid tablet and capsule formulations has been developed by applying Fourier-transform Infrared (FT-IR transmission spectroscopy for regular quality monitoring. The newly developed method avoids the sample preparation, except grinding for pellet formation and does not involve consumption of any solvent as it absolutely eliminates the need of extraction. KBr pellets were employed for the appraisal of azithromycin while acquiring spectra of standards as well as samples on FT-IR. By selecting the FT-IR carbonyl band (C=O in the region 1,744–1,709 cm−1 the calibration model was developed based on simple Beer’s law. The excellent regression coefficient (R2 0.999 was accomplished for calibration set having standard error of calibration equal to 0.01 mg. The current work exposes that transmission FT-IR spectroscopy can definitely be applied to determine the exact amount of azithromycin to control the processing and quality of solid formulations with reduced cost and short analysis time.

Facile preparation of squarylium dye sensitized TiO{sub 2} nanoparticles and their enhanced visible-light photocatalytic activity

Energy Technology Data Exchange (ETDEWEB)

Li, Zhongyu, E-mail: zhongyuli@mail.tsinghua.edu.cn [Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Changzhou University, Changzhou 213164 (China); Changzhou Expansion New Stuff Technology Limited Company, Changzhou 213122 (China); Fang, Yongling [Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Changzhou University, Changzhou 213164 (China); Zhan, Xueqiu [Department of Basic Courses, Wuxi Institute of Technology, Wuxi 214121 (China); Xu, Song [Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Changzhou University, Changzhou 213164 (China)

2013-07-05

Highlights: •ISQ dye sensitized TiO{sub 2} nanoparticles were prepared via a facile solution method. •ISQ/TiO{sub 2} nanoparticles exhibited significantly enhanced visible light activity. •ISQ/TiO{sub 2} showed high visible light photocatalytic activity over MB decomposition. •ISQ/TiO{sub 2} nanoparticles exhibited good photocatalytic stability. -- Abstract: A squarylium dye, 1,3-bis[(3,3-dimethylindolin-2-ylidene)methyl]squaraine (ISQ) sensitized TiO{sub 2} nanoparticles photocatalysts with different mass ratio of ISQ to TiO{sub 2} were facilely prepared by blending ISQ and TiO{sub 2} in ethanol solution. The resulting composite photocatalysts were characterized by the X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectra (FT-IR) and UV–vis diffuse reflectance spectroscope (DRS). The visible light photocatalytic activities of ISQ sensitized TiO{sub 2} nanoparticles were evaluated using the degradation of methylene blue (MB) as a photodegradation target. The results showed that photo-response of the ISQ sensitized TiO{sub 2} nanoparticles were remarkably extended to visible-light region, and the ISQ dye sensitized TiO{sub 2} exhibited significantly enhanced photocatalytic activity under visible light irradiation. The maximum photocatalytic activity of the ISQ sensitized TiO{sub 2} was found at a composite photocatalyst (mass ratio of ISQ to TiO{sub 2} was 1:3), and its degradation efficiency of MB reached approximately 98% in 2 h under visible light irradiation. Furthermore, a possible mechanism for the photocatalytic oxidative degradation was also proposed.

Seguimiento por espectroscopia infrarroja (FT-IR de la copolimerización de TEOS (tetraetilortosilicato y PDMS (polidimetilsiloxano en presencia de tbt (tetrabutiltitanio

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Téllez, L.

2004-10-01

Full Text Available Hybrid materials have been prepared in this work through the reactions of Si and Ti alkoxides (TEOS and TBT, respectively and polydimethil siloxane (PDMS. These reactions have been studied by means of FT-IR spectroscopy during the whole reaction time. The hydrolysis of TEOS molecule has been followed by the 880 cm-1 band, and the self-condensation reactions through the 1180 and 1150 cm-1 bands. Polycondesation reaction between Si-OH groups and PDMS molecules has been followed by the 850 cm-1 band. On the other hand, the hydrolysis reaction of TBT and the self-condensation of Ti-OH groups have been followed by the 1130 and 770-510 cm-1 bands, respectively. Finally the condensation reaction between Si-OH and Ti-OH groups have been studied by the 936 cm-1 band. Results have shown that hydrolysis and condensation reactions are depending on TBT concentration. The formation of Si-O-Si cross-linked structures increases with the TBT concentrations in the reaction. The selfcondensation reaction of Si-OH grups or Ti-OH grous is very reapid forming Si-O-Si and Ti-O-Ti bonds, respectively. However, the Si-O-Ti bonds which are formed during the first moments of reaction are also rapidly broken due to H2O molecules or the reaction medium. The evolution of PDMS linear and cyclic molecules is also studied.

Se han preparado materiales híbridos por medio de reacciones de hidrólisis y condensación de alcóxidos de Si y Ti (TEOS y TBT, respectivamente y de reacciones de copolimerización de éstos con polidimetilsiloxano (PDMS. Se han estudiado las citadas reacciones mediante espectroscopia FT-IR, desde el mismo comienzo hasta la obtención del material final. La hidrólisis del TEOS así como la autocondensación del os grupos Si-OH generados tanto para formar cadenas entrecruzadas como lineales se han seguido mediante las bandas situadas a 880, 1180 y 1150 cm-1, respectivamente. La policondensación de dichos grupos con PDMS se ha seguido por la banda a

Non-equilibrium nitrogen DC-arc plasma treatment of TiO2 nanopowder.

Science.gov (United States)

Suzuki, Yoshikazu; Gonzalez-Aguilar, José; Traisnel, Noel; Berger, Marie-Hélène; Repoux, Monique; Fulcheri, Laurent

2009-01-01

Non-equilibrium nitrogen DC-arc plasma treatment of a commercial TiO2 anatase nanopowder was examined to obtain nitrogen-doped TiO2. By using a non-thermal discharge at low current (150 mA) and high voltage (1200 V) using pure N2 gas, light yellowish-gray TiO2 powder was successfully obtained within a short period of 5-10 min. XPS and TEM-EELS studies confirmed the existence of doped nitrogen. Due to the relatively mild conditions (plasma power of 180 W), metastable anatase structure and fine crystallite size of TiO2 (ca. 10 nm) were maintained after the plasma treatment. The in-flight powder treatment system used in this study is promising for various type of powder treatment.

Effects of HVEM irradiation on ordered phases in Ni-Ti

International Nuclear Information System (INIS)

Pelton, A.R.

1983-01-01

Various ordered phases in the Ni-Ti system were subjected to electron irradiation in the Berkeley HVEM. Austenitic NiTi (B2 structure) disorders and turns amorphous with room-temperature irradiations at accelerating potentials between 1 and 1.5 MeV. Total doses for the onset of amorphiticity range between 0.7 x 10 22 and 3 x 10 22 e.cm -2 (0.4 to 1.0dpa). At 90K the dose requirement decreases to 4 x 10 20 e.cm -2 (approx. 10 -2 dpa). Martensitic NiTi (distorted monoclinic structure) readily detwins and transforms to austenite when irradiated for short times (approx. 10 seconds). Vapor-deposited amorphous films were crystallized to produce NiTi, Phase X (ordered nickel-rich phase with unknown structure) and Ni 3 Ti (DO 24 structure). Upon electron irradiation, NiTi and Phase X disorder and become amorphous, while Ni 3 Ti disorders but does not turn amorphous with doses up to 4 x 10 22 e.cm -2 at 90K. These results are discussed in terms of the requirement of a critical concentration of defects and their relative mobilities. Brimhall's solubility criteria for amorphization of ordered alloys by ion bombardment is apparantly applicable to electron-induced crystalline to amorphous transitions in this alloy

Toxicological Assessment and UV/TiO2-Based Induced Degradation Profile of Reactive Black 5 Dye

Science.gov (United States)

Bilal, Muhammad; Rasheed, Tahir; Iqbal, Hafiz M. N.; Hu, Hongbo; Wang, Wei; Zhang, Xuehong

2018-01-01

In this study, the toxicological and degradation profile of Reactive Black 5 (RB5) dye was evaluated using a UV/TiO2-based degradation system. Fourier transform infrared spectroscopy (FT-IR), thin layer chromatography (TLC), high-performance liquid chromatography (HPLC) and ultra-performance liquid chromatography coupled with mass spectrometry (UPLC-MS) techniques were used to evaluate the degradation level of RB5. The UV-Vis spectral analysis revealed the disappearance of peak intensity at 599 nm (λmax). The FT-IR spectrum of UV/TiO2 treated dye sample manifest appearance of new peaks mainly because of the degraded product and/or disappearance of some characteristics peaks which were present in the untreated spectrum. The HPLC profile verified the RB5 degradation subject to the formation of metabolites at different retention times. A stable color removal higher than 96% with COD removal in the range of 74-82.3% was noted at all evaluated dye concentrations. The tentative degradation pathway of RB5 is proposed following a careful analysis of the intermediates identified by UPLC-MS. Toxicity profile of untreated and degraded dye samples was monitored using three types of human cell lines via MTT assay and acute toxicity testing with Artemia salina. In conclusion, the UV/TiO2-based degradation system could be effectively employed for the remediation of textile wastewater comprising a high concentration of reactive dyes.

Keramzito gamyba naudojant nesipučiantį molį, sapropelį ir glicerolį

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Giedrius VAICKELIONIS

2011-09-01

Full Text Available Šio darbo tikslas - ištirti keraminių plytų ir čerpių gamybai netinkančio, silpnai pučiančiosi (išsipūtimo koeficientas Kp = 2 - 2,5 ir nesipučiančio (Kp < 2 molio panaudojimo keramzito gamybai galimybes, molio pūtimuisi gerinti dedant šių organinių priedų: biodyzelino gamybos atliekos - glicerolio, medienos drožlių plokščių pjuvenų ir organinio sapropelio. Keramzito izoliacinės savybės gerėja didėjant išdegto molio šukės akytumui. Kad molis pūstųsi geriau, į jį dažnai įmaišoma organinių priedų. Tirtas Krūnos telkinio III sluoksnio karbonatingasis molis be priedų netinka keramzito gamybai dėl per mažo išsipūtimo koeficiento (Kp = 1,25. Tam tikslui į išdžiovintą smulkiai maltą molį buvo įmaišoma įvairūs kiekiai (0 %, 1 %, 2 %, 3 %, 5 %, 7 % ir 10 % organinių atliekų. Granulės gamintos su vienu arba keliais pasirinktais degimo metu dujas išskiriančiais priedais. Suformuotos ir išdžiovintos granulės degtos skirtingose temperatūrose iki jų apsilydimo temperatūros - nuo 1090 °C iki 1170 °C. Nustatytas išdegtų granulių pūtimasis ir vandens įmirkis. Tyrimų metu nustatyta, kad organinės atliekos yra efektyvus priedas, didinantis molio struktūros akytumą. Be to, molyje neturi būti daugiau kaip 5 % sapropelio, rekomenduojamas glicerolio kiekis yra 1 % - 3 %, optimalus pjuvenų kiekis - 3 %. Bandinių, pagamintų su nurodytais priedų kiekiais ir išdegtų skirtingose temperatūrose, vandens įmirkis neviršija 15 %.http://dx.doi.org/10.5755/j01.ms.17.3.600

Dynamic Hydrogen Production from Methanol/Water Photo-Splitting Using Core@Shell-Structured CuS@TiO2 Catalyst Wrapped by High Concentrated TiO2 Particles

Directory of Open Access Journals (Sweden)

Younghwan Im

2013-01-01

Full Text Available This study focused on the dynamic hydrogen production ability of a core@shell-structured CuS@TiO2 photocatalyst coated with a high concentration of TiO2 particles. The rectangular-shaped CuS particles, 100 nm in length and 60 nm in width, were surrounded by a high concentration of anatase TiO2 particles (>4~5 mol. The synthesized core@shell-structured CuS@TiO2 particles absorbed a long wavelength (a short band gap above 700 nm compared to that pure TiO2, which at approximately 300 nm, leading to easier electronic transitions, even at low energy. Hydrogen evolution from methanol/water photo-splitting over the core@shell-structured CuS@TiO2 photocatalyst increased approximately 10-fold compared to that over pure CuS. In particular, 1.9 mmol of hydrogen gas was produced after 10 hours when 0.5 g of 1CuS@4TiO2 was used at pH = 7. This level of production was increased to more than 4-fold at higher pH. Cyclic voltammetry and UV-visible absorption spectroscopy confirmed that the CuS in CuS@TiO2 strongly withdraws the excited electrons from the valence band in TiO2 because of the higher reduction potential than TiO2, resulting in a slower recombination rate between the electrons and holes and higher photoactivity.

Crack-closing of cement mortar beams using NiTi cold-drawn SMA short fibers

Science.gov (United States)

Choi, Eunsoo; Kim, Dong Joo; Chung, Young-Soo; Kim, Hee Sun; Jung, Chungsung

2015-01-01

In this study, crack-closing tests of mortar beams reinforced by shape memory alloy (SMA) short fibers were performed. For this purpose, NiTi SMA fibers with a diameter of 0.965 mm and a length of 30 mm were made from SMA wires of 1.0 mm diameter by cold drawing. Four types of SMA fibers were prepared, namely, straight and dog-bone-shaped fiber and the two types of fibers with paper wrapping in the middle of the fibers. The paper provides an unbonded length of 15 mm. For bending tests, six types of mortar beams with the dimensions of 40 mm × 40 mm × 160 mm (B×H×L) were prepared. The SMA fibers were placed at the bottom center of the beams along with an artificial crack of 10 mm depth and 1 mm thickness. This study investigated the influence of SMA fibers on the flexural strength of the beams from the measured force- deflection curves. After cracking, the beams were heated at the bottom by fire to activate the SMA fibers. Then, the beams recovered the deflection, and the cracks were closed. This study evaluated crack-closing capacity using the degree of crack recovery and deflection-recovery factor. The first factor is estimated from the crack-width before and after crack-closing, and the second one is obtained from the downward deflection due to loading and the upward deflection due to the closing force of the SMA fibers.

Catalysis of a Nanometre Solid Super Acid of SO42-/TiO2 on the Thermal Decomposition of Ammonium Nitrate

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Xiaolan Song

2016-03-01

Full Text Available Raw TiO2 nanoparticles were prepared using the hydroly‐ sis of TiCl4. The nanoparticles were subjected to a surface treatment in diluted sulphuric acid and, subsequently, calcined at different temperatures. Then, a type of super solid acid (SO42-/TiO2 with particle sizes of 20∼30 nm was fabricated. The catalysis of SO42-/TiO2 on the thermolysis of ammonium nitrate (AN was probed using thermal analysis. For SO42-/TiO2 (AN doped with 3%SO42-/TiO2, the onset temperature decreased by 19°C and the peak tem‐ perature decreased by 15.8°C. For TiO2 (AN doped with 3%TiO2, the peak temperature decreased by only 0.5°C. Using the DSC-IR technology, the gas products of the decomposition of 3%SO42-/TiO2-doped AN were detected. We found that the products were mainly N2O (g and a small amount of H2O (g, and that no NH3 (g or HNO3 (g was detected, which ascertained the decomposition reaction of NH4NO3→N2O(g+H2O(g. In addition, the catalysis mechanism of SO42-/TiO2 on the AN decomposi‐ tion was discussed in detail.

Synthesis of Nano-Ilmenite (FeTiO3) doped TiO2/Ti Electrode for Photoelectrocatalytic System

Science.gov (United States)

Hikmawati; Watoni, A. H.; Wibowo, D.; Maulidiyah; Nurdin, M.

2017-11-01

Ilmenite (FeTiO3) doped on Ti and TiO2/Ti electrodes were successfully prepared by using the sol-gel method. The structure, morphology, and optical properties of FeTiO3 are characterized by XRD, UV-Vis DRS, and SEM. The FeTiO3 and TiO2 greatly affect the photoelectrocatalysis performance characterized by Linear Sweep Voltammetry (LSV) and Cyclic Voltammetry (CV). The characterization result shows a band gap of FeTiO3 is 2.94 eV. XRD data showed that FeTiO3 formed at 2θ were 35.1° (110), 49.9° (024), and 61.2° (214). The morphology of FeTiO3/Ti and FeTiO3.TiO2/Ti using SEM shows that the formation of FeTiO3 thin layer signifies the Liquid Phase Deposition method effectively in the coating process. Photoelectrochemical (PEC) test showed that FeTiO3.TiO2/Ti electrode was highly oxidation responsive under visible light compared to the FeTiO3/Ti electrodes i.e. 7.87×10-4 A and 9.87×10-5 A. Degradation test of FeTiO3/Ti and FeTiO3.TiO2/Ti electrodes on titan yellow showed that the percentages of degradation with photoelectrocatalysis at 0.5 mg/L were 41% and 43%, respectively.

TiO2 coated SnO2 nanosheet films for dye-sensitized solar cells

International Nuclear Information System (INIS)

Cai Fengshi; Yuan Zhihao; Duan Yueqing; Bie Lijian

2011-01-01

TiO 2 -coated SnO 2 nanosheet (TiO 2 -SnO 2 NS) films about 300 nm in thickness were fabricated on fluorine-doped tin oxide glass by a two-step process with facile solution-grown approach and subsequent hydrolysis of TiCl 4 aqueous solution. The as-prepared TiO 2 -SnO 2 NSs were characterized by scanning electron microscopy and X-ray diffraction. The performances of the dye-sensitized solar cells (DSCs) with TiO 2 -SnO 2 NSs were analyzed by current-voltage measurements and electrochemical impedance spectroscopy. Experimental results show that the introduction of TiO 2 -SnO 2 NSs can provide an efficient electron transition channel along the SnO 2 nanosheets, increase the short current density, and finally improve the conversion efficiency for the DSCs from 4.52 to 5.71%.

Synthesis of Nanocrystalline SnO2 Modified TiO2:a Material for Carbon Monoxide Gas Sensor

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A. B. BODADE

2008-11-01

Full Text Available Nanocrystalline SnO2 doped TiO2 having average crystallite size of 45-50 nm were synthesized by the sol-gel method and studied for gas sensing behavior to reducing gases like CO, liquefied petroleum gas (LPG, NH3 and H2. The material characterization was done by using X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FT-IR and scanning electron microscope (SEM. The sensitivity measurements were carried out as a function of different operating temperature in SnO2 doped TiO2. The 15 wt.% SnO2 doped TiO2 based CO sensor shows better sensitivity at an operating temperature 240°C Incorporation of 0.5 wt% Pd improved the sensitivity, selectivity, response time and reduced the operating temperature from 240°C to 200°C for CO sensor.

Mesoporous silica nanoparticle supported PdIr bimetal catalyst for selective hydrogenation, and the significant promotional effect of Ir

Energy Technology Data Exchange (ETDEWEB)

Yang, Hui; Huang, Chao; Yang, Fan [The Key Laboratory of Fuel Cell Technology of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641 (China); Yang, Xu [Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou (China); Du, Li [The Key Laboratory of Fuel Cell Technology of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641 (China); Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou (China); Liao, Shijun, E-mail: chsjliao@scut.edu.cn [The Key Laboratory of Fuel Cell Technology of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641 (China); Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou (China)

2015-12-01

Graphical abstract: A mesoporous silica nanoparticle (MSN) supported bimetal catalyst, PdIr/MSN, was prepared by a facile impregnation and hydrogen reduction method. The strong promotional effect of Ir was observed and thoroughly investigated. At the optimal molar ratio of Ir to Pd (N{sub Ir}/N{sub Pd} = 0.1), the activity of PdIr{sub 0.1}/MSN was up to eight times and 28 times higher than that of monometallic Pd/MSN and Ir/MSN, respectively. The catalysts were characterized comprehensively by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and hydrogen temperature programmed reduction, which revealed that the promotional effect of Ir may be due to the enhanced dispersion of active components on the MSN, and to the intensified Pd–Ir electronic interaction caused by the addition of Ir. - Highlights: • Mesoporous nanoparticles were synthesized and used as support for metal catalyst. • PdIr bimetallic catalyst exhibited significantly improved hydrogenation activity. • The strong promotion of Ir was recognized firstly and investigated intensively. • PdIr exhibits 18 times higher activity than Pd to the hydrogenation of nitrobenzene. - Abstract: A mesoporous silica nanoparticle (MSN) supported bimetal catalyst, PdIr/MSN, was prepared by a facile impregnation and hydrogen reduction method. The strong promotional effect of Ir was observed and thoroughly investigated. At the optimal molar ratio of Ir to Pd (N{sub Ir}/N{sub Pd} = 0.1), the activity of PdIr{sub 0.1}/MSN was up to eight times and 28 times higher than that of monometallic Pd/MSN and Ir/MSN, respectively. The catalysts were characterized comprehensively by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and hydrogen temperature programmed reduction, which revealed that the promotional effect of Ir may be due to the enhanced dispersion of active components on the MSN, and to the intensified Pd–Ir electronic interaction

Antibacterial abilities and biocompatibilities of Ti-Ag alloys with nanotubular coatings

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Liu X

2016-11-01

Full Text Available Xingwang Liu,1 Ang Tian,2 Junhua You,3 Hangzhou Zhang,4 Lin Wu,5 Xizhuang Bai,1 Zeming Lei,1 Xiaoguo Shi,2 Xiangxin Xue,2 Hanning Wang4 1Department of Orthopedics, The People’s Hospital of China Medical University, 2Liaoning Provincial Universities Key Laboratory of Boron Resource Ecological Utilization Technology and Boron Materials, Northeastern University, 3School of Materials Science and Engineering, Shenyang University of Technology, 4Department of Sports Medicine and Joint Surgery, The First Affiliated Hospital of China Medical University, 5Department of Prosthodontics, School of Stomatology, China Medical University, Shenyang, People’s Republic of China Purpose: To endow implants with both short- and long-term antibacterial activities without impairing their biocompatibility, novel Ti–Ag alloy substrates with different proportions of Ag (1, 2, and 4 wt% Ag were generated with nanotubular coverings (TiAg-NT. Methods: Unlike commercial pure Ti and titania nanotube, the TiAg-NT samples exhibited short-term antibacterial activity against Staphylococcus aureus (S. aureus, as confirmed by scanning electron microscopy and double staining with SYTO 9 and propidium iodide. A film applicator coating assay and a zone of inhibition assay were performed to investigate the long-term antibacterial activities of the samples. The cellular viability and cytotoxicity were evaluated through a Cell Counting Kit-8 assay. Annexin V-FITC/propidium iodide double staining was used to assess the level of MG63 cell apoptosis on each sample. Results: All of the TiAg-NT samples, particularly the nanotube-coated Ti–Ag alloy with 2 wt% Ag (Ti2%Ag-NT, could effectively inhibit bacterial adhesion and kill the majority of adhered S. aureus on the first day of culture. Additionally, the excellent antibacterial abilities exhibited by the TiAg-NT samples were sustained for at least 30 days. Although Ti2%Ag-NT had less biocompatibility than titania nanotube, its

Electrosynthesis of Ti5Si3, Ti5Si3/TiC, and Ti5Si3/Ti3SiC2 from Ti-Bearing Blast Furnace Slag in Molten CaCl2

Science.gov (United States)

Li, Shangshu; Zou, Xingli; Zheng, Kai; Lu, Xionggang; Chen, Chaoyi; Li, Xin; Xu, Qian; Zhou, Zhongfu

2018-04-01

Ti5Si3, Ti5Si3/TiC, and Ti5Si3/Ti3SiC2 have been electrochemically synthesized from the Ti-bearing blast furnace slag/TiO2 and/or C mixture precursors at a cell voltage of 3.8 V and 1223 K to 1273 K (950 °C to 1000 °C) in molten CaCl2. The pressed porous mixture pellets were used as the cathode, and a solid oxide oxygen-ion-conducting membrane (SOM)-based anode was used as the anode. The phase composition and morphologies of the cathodic products were systematically characterized. The final products possess a porous nodular microstructure due to the interconnection of particles. The variations of impurity elements, i.e., Ca, Mg, and Al, have been analyzed, and the result shows that Ca and Mg can be almost completely removed; however, Al cannot be easily removed from the pellet due to the formation of Ti-Al alloys during the electroreduction process. The electroreduction process has also been investigated by the layer-depended phase composition analysis of the dipped/partially reduced pellets to understand the detailed reaction process. The results indicate that the electroreduction process of the Ti-bearing blast furnace slag/TiO2 and/or C mixture precursors can be typically divided into four periods, i.e., (i) the decomposition of initial Ca(Mg,Al)(Si,Al)2O6, (ii) the reduction of Ti/Si-containing intermediate phases, (iii) the removal of impurity elements, and (iv) the formation of Ti5Si3, TiC, and Ti3SiC2. It is suggested that the SOM-based anode process has great potential to be used for the direct and facile preparation of Ti alloys and composites from cheap Ti-containing ores.

BOOTES-IR: near IR follow-up GRB observations by a robotic system

International Nuclear Information System (INIS)

Castro-Tirado, A.J.; Postrigo, A. de Ugarte; Jelinek, M.

2005-01-01

BOOTES-IR is the extension of the BOOTES experiment, which operates in Southern Spain since 1998, to the near IR (NIR). The goal is to follow up the early stage of the gamma ray burst (GRB) afterglow emission in the NIR, alike BOOTES does already at optical wavelengths. The scientific case that drives the BOOTES-IR performance is the study of GRBs with the support of spacecraft like INTEGRAL, SWIFT and GLAST. Given that the afterglow emission in both, the NIR and the optical, in the instances immediately following a GRB, is extremely bright (reached V = 8.9 in one case), it should be possible to detect this prompt emission at NIR wavelengths too. The combined observations by BOOTES-IR and BOOTES-1 and BOOTES-2 will allow for real time identification of trustworthy candidates to have a high redshift (z > 5). It is expected that, few minutes after a GRB, the IR magnitudes be H ∼ 7-10, hence very high quality spectra can be obtained for objects as far as z = 10 by larger instruments

Development of Cytoplasmic Male Sterile IR24 and IR64 Using CW-CMS/Rf17 System.

Science.gov (United States)

Toriyama, Kinya; Kazama, Tomohiko

2016-12-01

A wild-abortive-type (WA) cytoplasmic male sterility (CMS) has been almost exclusively used for breeding three-line hybrid rice. Many indica cultivars are known to carry restorer genes for WA-CMS lines and cannot be used as maintainer lines. Especially elite indica cultivars IR24 and IR64 are known to be restorer lines for WA-CMS lines, and are used as male parents for hybrid seed production. If we develop CMS IR24 and CMS IR64, the combination of F1 pairs in hybrid rice breeding programs will be greatly broadened. For production of CMS lines and restorer lines of IR24 and IR64, we employed Chinese wild rice (CW)-type CMS/Restorer of fertility 17 (Rf17) system, in which fertility is restored by a single nuclear gene, Rf17. Successive backcrossing and marker-assisted selection of Rf17 succeeded to produce completely male sterile CMS lines and fully restored restorer lines of IR24 and IR64. CW-cytoplasm did not affect agronomic characteristics. Since IR64 is one of the most popular mega-varieties and used for breeding of many modern varieties, the CW-CMS line of IR64 will be useful for hybrid rice breeding.

Selective Iron(III ion uptake using CuO-TiO2 nanostructure by inductively coupled plasma-optical emission spectrometry

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Rahman Mohammed M

2012-12-01

Full Text Available Abstract Background CuO-TiO2 nanosheets (NSs, a kind of nanomaterials is one of the most attracting class of transition doped semiconductor materials due to its interesting and important optical, electrical, and structural properties and has many technical applications, such as in metal ions detection, photocatalysis, Chemi-sensors, bio-sensors, solar cells and so on. In this paper the synthesis of CuO-TiO2 nanosheets by the wet-chemically technique is reported. Methods CuO-TiO2 NSs were prepared by a wet-chemical process using reducing agents in alkaline medium and characterized by UV/vis., FT-IR spectroscopy, X-ray photoelectron spectroscopy (XPS, powder X-ray diffraction (XRD, and field-emission scanning electron microscopy (FE-SEM etc. Results The structural and optical evaluation of synthesized NSs were measured by XRD pattern, Fourier transform infrared (FT-IR and UV–vis spectroscopy, respectively which confirmed that the obtained NSs are well-crystalline CuO-TiO2 and possessing good optical properties. The morphological analysis of CuO-TiO2 NSs was executed by FE-SEM, which confirmed that the doped products were sheet-shaped and growth in large quantity. Here, the analytical efficiency of the NSs was applied for a selective adsorption of iron(III ion prior to detection by inductively coupled plasma-optical emission spectrometry (ICP-OES. The selectivity of NSs towards various metal ions, including Au(III, Cd(II, Co(II, Cr(III, Fe(III, Pd(II, and Zn(II was analyzed. Conclusions Based on the selectivity study, it was confirmed that the selectivity of doped NSs phase was the most towards Fe(III ion. The static adsorption capacity for Fe(III was calculated to be 110.06 mgg−1. Results from adsorption isotherm also verified that the adsorption process was mainly monolayer-adsorption onto a surface containing a finite number of CuO-TiO2 NSs adsorption sites.

The TApIR experiment. IR absorption spectra of liquid hydrogen isotopologues

International Nuclear Information System (INIS)

Groessle, Robin

2015-01-01

The scope of the thesis is the infrared absorption spectroscopy of liquid hydrogen isotopologues with the tritium absorption infrared spectroscopy (TApIR) experiment at the tritium laboratory Karlsruhe (TLK). The calibration process from the sample preparation to the reference measurements are described. A further issue is the classical evaluation of FTIR absorption spectra and the extension using the rolling circle filter (RCF) including the effects on statistical and systematical errors. The impact of thermal and nuclear spin temperature on the IR absorption spectra is discussed. An empirical based modeling for the IR absorption spectra of liquid hydrogen isotopologues is performed.

Structural Modification of Sol-Gel Synthesized V2O5 and TiO2 Thin Films with/without Erbium Doping

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Fatma Pınar Gökdemir

2014-01-01

Full Text Available Comparative work of with/without erbium- (Er- doped vanadium pentoxide (V2O5 and titanium dioxide (TiO2 thin films were carried out via sol-gel technique by dissolving erbium (III nitrate pentahydrate (Er(NO33·5H2O in vanadium (V oxoisopropoxide (OV[OCH(CH32]3 and titanium (IV isopropoxide (Ti[OCH(CH32]4. Effect of Er doping was traced by Fourier transform IR (FTIR, thermogravimetric/differential thermal (TG/DTA, and photoluminescence measurements. UV-Vis transmission/absorption measurement indicated a blue shift upon Er doping in V2O5 film due to the softening of V=O bond while appearance of typical absorption peaks in Er-doped TiO2 film. Granule size of the films increased (reduced upon Er substitution on host material compared to undoped V2O5 and TiO2 films, respectively.

微量TiC对Mo-Ti-Zr-TiC合金性能与显微组织的影响%Effect of Trace TiC on Property and Microstructure of Mo-Ti-Zr-TiC Alloy

Institute of Scientific and Technical Information of China (English)

钱昭; 范景莲; 成会朝; 田家敏

2012-01-01

采用粉末冶金方法制备Mo-Ti-Zr-TiC合金,研究微量TiC的添加对Mo-Ti-Zr-TiC合金的拉伸性能和显微组织的影响.结果表明,在Mo-Ti-Zr合金中添加微量TiC(0.1％～0.5％,质量分数)后,合金的相对密度和室温抗拉强度得到了提高,当TiC添加量为0.4％时,合金强度最高,较Mo-Ti-Zr合金提高了28.1％.微量TiC的添加,阻碍了合金烧结过程中的晶粒长大,合金晶粒尺寸随TiC添加量的增加而降低.添加的细小TiC粒子在高温烧结过程中或与坯体中的微量氧发生反应形成了由Mo、Ti、C及O 4种元素组成的(Mo,Ti)xOyCz细小复合第二相粒子,或发生团聚结成大颗粒,对合金起到净化晶界氧和弥散强化的作用,因而合金的性能相比Mo-Ti-Zr合金有了较明显的提高.%Mo-Ti-Zr-TiC alloy was prepared via powder metallurgy method. The effects of trace TiC additive on the mechanical properties and microstructure of TiC reinforced Mo-Ti-Zr-TiC alloy were studied. The results indicate that the relative density and the tensile strength at room temperature of Mo-Ti-Zr-TiC alloy is effectively enhanced by adding trace TiC (0.1wt%~0.5wt%). The tensile strength achieves the highest value when the content of TiC is 0.4wt%, which is 28.1% higher than that of Mo-Ti-Zr alloy. The adding of trace TiC can inhibit the grain growth during alloy sintering process, which leads to the decrease of grain sizes with the rise of TiC content. A part of the fine TiC particles react with trace oxygen in molybdenum matrix to form (Mo,Ti)xOyC2 compound second phase particles during high temperature sintering, while the other part are agglomerated into large particles, which play a role in grain boundaries purification and dispersion-strengthening.

Cutting NiTi with Femtosecond Laser

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L. Quintino

2013-01-01

Full Text Available Superelastic shape memory alloys are difficult to machine by thermal processes due to the facility for Ti oxidation and by mechanical processes due to their superelastic behavior. In this study, femtosecond lasers were tested to analyze the potential for machining NiTi since femtosecond lasers allow nonthermal processing of materials by ablation. The effect of processing parameters on machining depth was studied, and material removal rates were computed. Surfaces produced were analyzed under SEM which shows a resolidified thin layer with minimal heat affected zones. However, for high cutting speeds, that is, for short interaction times, this layer was not observed. A depletion of Ni was seen which may be beneficial in biomedical applications since Ni is known to produce human tissue reactions in biophysical environments.

New nanostructured silica incorporated with isolated Ti material for the photocatalytic conversion of CO2 to fuels

Science.gov (United States)

2014-01-01

In this work, new nanoporous silica (Korea Advanced Institute of Science and Technology-6 (KIT-6)-dried or KIT-6-calcined) incorporated with isolated Ti materials with different Si/Ti ratios (Si/Ti = 200, 100, and 50) has been synthesized and investigated to establish photocatalytic reduction of CO2 in the presence of H2O vapors. The properties of the materials have been characterized through N2 adsorption/desorption, UV-vis, TEM, FT-IR, and XPS analysis techniques. The intermediate amount of the isolated Ti (Si/Ti = 100) has resulted to be more uniformly distributed on the surface and within the three-dimensional pore structure of the KIT-6 material, without its structure collapsing, than the other two ratios (Si/Ti = 200 and 50). However, titania agglomerates have been observed to have formed due to the increased Ti content (Si/Ti = 50). The Ti-KIT-6 (calcined) materials in the reaction showed higher activity than the Ti-KIT-6 (dried) materials, which produced CH4, H2, CO, and CH3OH (vapors) as fuel products. The Ti-KIT-6 (Si/Ti = 100) material also showed more OH groups, which are useful to obtain a higher production rate of the products, particularly methane, which was even higher than the rate of the best commercial TiO2 (Aeroxide P25, Evonik Industries AG, Essen, Germany) photocatalyst. PMID:24690396

Surface modified MXene Ti3C2 multilayers by aryl diazonium salts leading to large-scale delamination

Science.gov (United States)

Wang, Hongbing; Zhang, Jianfeng; Wu, Yuping; Huang, Huajie; Li, Gaiye; Zhang, Xin; Wang, Zhuyin

2016-10-01

Herein we report a simple and facile method to delaminate MXene Ti3C2 multilayers by the assistance of surface modification using aryl diazonium salts. The basic strategy involved the preparation of layered MAX Ti3AlC2 and the exfoliation of Ti3AlC2 into Ti3C2 multilayers, followed by Na+ intercalation and surface modification using sulfanilic acid diazonium salts. The resulting chemically grafted Ti3C2 flakes were characterized by Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS) to confirm the presence of the surface organic species. Ultraviolet-visible spectroscopy revealed that surface-modified MXene Ti3C2 sheets disperse well in water and the solutions obey Lambert-Beer's law. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to demonstrate the morphology and structure of delaminating MXene Ti3C2 flakes. The results indicated that chemical modification for MXene multilayers by aryl diazonium salts induced swelling that conversely weakened the bonds between MX layers, hence leading to large-scale delamination of multilayered MXene Ti3C2via mild sonication. Advantages of the present approach rely not only on the simplicity and efficiency of the delamination procedure but also on the grafting of aryl groups to MXene surfaces, highly suitable for further applications of the newly discovered two-dimensional materials.

Study of the degradation of liquid-organic radioactive wastes by electrochemical methods

International Nuclear Information System (INIS)

Hernandez A, J. I.

2015-01-01

In this study degradation studies were performed on blank samples, in which two electrochemical cells with different electrodes were used, the first is constituted by mesh electrodes Ti/Ir-Ta/Ti and the second by rod electrodes Ti/Ddb, using as reference an electrolytic medium of scintillation liquid and scintillation liquid more water, applying different potentials ranging from 1 to 25 V. After obtaining the benchmarks, the treatment was applied to samples containing organic liquid radioactive waste, in this case a short half-life radioisotope as Sulfur-35, the degradation characterization of organic compounds was performed in infrared spectrometry. (Author)

Study of the degradation of liquid-organic radioactive wastes by electrochemical methods; Estudio de la degradacion de desechos liquidos-organicos radiactivos mediante metodos electroquimicos

Energy Technology Data Exchange (ETDEWEB)

Hernandez A, J. I.

2015-07-01

In this study degradation studies were performed on blank samples, in which two electrochemical cells with different electrodes were used, the first is constituted by mesh electrodes Ti/Ir-Ta/Ti and the second by rod electrodes Ti/Ddb, using as reference an electrolytic medium of scintillation liquid and scintillation liquid more water, applying different potentials ranging from 1 to 25 V. After obtaining the benchmarks, the treatment was applied to samples containing organic liquid radioactive waste, in this case a short half-life radioisotope as Sulfur-35, the degradation characterization of organic compounds was performed in infrared spectrometry. (Author)

The effects of boron in TiAl/Ti3Al

International Nuclear Information System (INIS)

Feng, C.R.; Michel, D.J.; Crowe, C.R.

1989-01-01

The authors discuss the TiAl/Ti 3 Al interfacial misfit dislocations structures investigated by TEM in Ti-45Al alloy and Ti-45Al/TiB 2 composite. For TiAl with c/a = 1.02, only a single set of misfit dislocation arrays are crystallographically possible; these were observed in Ti-45Al alloy. However, the observation of three sets of misfit dislocation arrays in the Ti-45Al/TiB 2 composite suggests that the occupation of octahedral sites in the TiAl structure by excess boron was responsible for a decrease in the c/a ratio leading to an increased fcc character of the TiAl at the TiAl/Ti 3 Al interface

Preparation of Oleyl Phosphate-Modified TiO2/Poly(methyl methacrylate Hybrid Thin Films for Investigation of Their Optical Properties

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Masato Fujita

2015-01-01

Full Text Available TiO2 nanoparticles (NPs modified with oleyl phosphate were synthesized through stable Ti–O–P bonds and were utilized to prepare poly(methyl methacrylate- (PMMA- based hybrid thin films via the ex situ route for investigation of their optical properties. After surface modification of TiO2 NPs with oleyl phosphate, IR and 13C CP/MAS NMR spectroscopy showed the presence of oleyl groups. The solid-state 31P MAS NMR spectrum of the product revealed that the signal due to oleyl phosphate (OP shifted upon reaction, indicating formation of covalent Ti–O–P bonds. The modified TiO2 NPs could be homogeneously dispersed in toluene, and the median size was 16.1 nm, which is likely to be sufficient to suppress Rayleigh scattering effectively. The TEM images of TiO2/PMMA hybrid thin films also showed a homogeneous dispersion of TiO2 NPs, and they exhibited excellent optical transparency even though the TiO2 content was 20 vol%. The refractive indices of the OP-modified TiO2/PMMA hybrid thin films changed higher with increases in TiO2 volume fraction, and the hybrid thin film with 20 vol% of TiO2 showed the highest refractive index (n = 1.86.

Spontaneous and Photoinduced Conversion of CO2 on TiO2 Anatase (001)/(101) Surfaces

Czech Academy of Sciences Publication Activity Database

Ferus, Martin; Kavan, Ladislav; Zukalová, Markéta; Zukal, Arnošt; Klementová, Mariana; Civiš, Svatopluk

2014-01-01

Roč. 118, č. 46 (2014), s. 26845-26850 ISSN 1932-7447 R&D Projects: GA ČR(CZ) GAP108/12/0814; GA MŠk LD14115; GA MŠk(CZ) LD13060 Grant - others:COST(XE) CM1104 Institutional support: RVO:61388955 ; RVO:61388980 ; RVO:68081707 Keywords : TiO2 * FT-IR spectroscopy * nanocrystalline anatase Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.772, year: 2014

Few-Layer MoS2 Nanodomains Decorating TiO2 Nanoparticles: A Case Study for the Photodegradation of Carbamazepine

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Sara Cravanzola

2018-03-01

Full Text Available S-doped TiO2 and hybrid MoS2/TiO2 systems have been synthesized, via the sulfidation with H2S of the bare TiO2 and of MoOx supported on TiO2 systems, with the aim of enhancing the photocatalytic properties of TiO2 for the degradation of carbamazepine, an anticonvulsant drug, whose residues and metabolites are usually inefficiently removed in wastewater treatment plants. The focus of this study is to find a relationship between the morphology/structure/surface properties and photoactivity. The full characterization of samples reveals the strong effects of the H2S action on the properties of TiO2, with the formation of defects at the surface, as shown by transmission electron microscopy (TEM and infrared spectroscopy (IR, while also the optical properties are strongly affected by the sulfidation treatment, with changes in the electronic states of TiO2. Meanwhile, the formation of small and thin few-layer MoS2 domains, decorating the TiO2 surface, is evidenced by both high-resolution transmission electron microscopy (HRTEM and UV-Vis/Raman spectroscopies, while Fourier-transform infrared (FTIR spectra give insights into the nature of Ti and Mo surface sites. The most interesting findings of our research are the enhanced photoactivity of the MoS2/TiO2 hybrid photocatalyst toward the carbamazepine mineralization. Surprisingly, the formation of hazardous compounds (i.e., acridine derivatives, usually obtained from carbamazepine, is precluded when treated with MoS2/TiO2 systems.

Design of H3PW12O40/TiO2 nano-photocatalyst for efficient photocatalysis under simulated sunlight irradiation

International Nuclear Information System (INIS)

Zhao, Kun; Lu, Ying; Lu, Nan; Zhao, Yahui; Yuan, Xing; Zhang, Hao; Teng, Lianghui; Li, Fu

2013-01-01

H 3 PW 12 O 40 /TiO 2 (PW 12 /TiO 2 ) nano-photocatalyst was successfully synthesized through a modified sol–gel-hydrothermal method. The X-ray diffraction (XRD) patterns, Fourier transform infrared (FT-IR) spectra, UV–vis diffuse reflectance spectrum (UV–vis DRS), and N 2 adsorption–desorption isotherms were characterized respectively to investigate the physical and chemical properties of prepared catalysts. Under simulated sunlight (320 nm 12 /TiO 2 . The results showed that the pollutants degradation followed first-order kinetics, and the kinetic constants of photocatalytic degradation of fuchsin acid, malachite green and PNP were 2.82, 4.66, and 3.48 times as great as that using pristine TiO 2 , respectively. The high pollutants degradation efficiency was ascribed to the synergistic effect between H 3 PW 12 O 40 and TiO 2 , which resulted in enhanced quantum efficiency and high light harvesting efficiency. We believe this work could provide new insights into the fabrication of photocatalyst with high photocatalytic performance and facilitate their practical application in environmental issues.

Liquid phase interaction in TiC0,5N0,5-TiNi-Mo and TiC0,5N0,5-TiNi-Ti-Mo

International Nuclear Information System (INIS)

Askarova, L.Kh; Grigorov, I.G.; Zajnulin, Yu.G.

1998-01-01

Using the methods of X ray diffraction analysis, electron microscopy and X ray spectrum microanalysis a study was made into specific features of phase and structure formation in alloys TiC 0,5 N 0,5 -TiNi-Mo and TiC 0,5 N 0,5 -TiNi-Mo in the presence of a liquid phase at temperatures of 1380-1600 deg C. It is revealed that the physical and chemical processes taking place during the liquid-phase sintering result in the formation of a three-phase alloy consisting of nonstoichiometric titanium carbonitride TiC 0.5-x N 0.5-x , a molybdenum base solid solution of titanium, nickel and carbon Mo(Ti, Ni, C) and one of two intermetallic compounds, either TiNi or Ni 3 Ti. Metallic element concentration in individual phase constituents of the alloy is determined by means of X ray spectrum microanalysis

Inhibition of PTP1B Restores IRS1-Mediated Hepatic Insulin Signaling in IRS2-Deficient Mice

Science.gov (United States)

González-Rodríguez, Águeda; Gutierrez, Jose A. Mas; Sanz-González, Silvia; Ros, Manuel; Burks, Deborah J.; Valverde, Ángela M.

2010-01-01

OBJECTIVE Mice with complete deletion of insulin receptor substrate 2 (IRS2) develop hyperglycemia, impaired hepatic insulin signaling, and elevated gluconeogenesis, whereas mice deficient for protein tyrosine phosphatase (PTP)1B display an opposing hepatic phenotype characterized by increased sensitivity to insulin. To define the relationship between these two signaling pathways in the regulation of liver metabolism, we used genetic and pharmacological approaches to study the effects of inhibiting PTP1B on hepatic insulin signaling and expression of gluconeogenic enzymes in IRS2−/− mice. RESEARCH DESIGN AND METHODS We analyzed glucose homeostasis and insulin signaling in liver and isolated hepatocytes from IRS2−/− and IRS2−/−/PTP1B−/− mice. Additionally, hepatic insulin signaling was assessed in control and IRS2−/− mice treated with resveratrol, an antioxidant present in red wine. RESULTS In livers of hyperglycemic IRS2−/− mice, the expression levels of PTP1B and its association with the insulin receptor (IR) were increased. The absence of PTP1B in the double-mutant mice restored hepatic IRS1-mediated phosphatidylinositol (PI) 3-kinase/Akt/Foxo1 signaling. Moreover, resveratrol treatment of hyperglycemic IRS2−/− mice decreased hepatic PTP1B mRNA and inhibited PTP1B activity, thereby restoring IRS1-mediated PI 3-kinase/Akt/Foxo1 signaling and peripheral insulin sensitivity. CONCLUSIONS By regulating the phosphorylation state of IR, PTB1B determines sensitivity to insulin in liver and exerts a unique role in the interplay between IRS1 and IRS2 in the modulation of hepatic insulin action. PMID:20028942

Study of the atomic ordering in the alloys Ni-Ir using diffuse X-ray scattering and pseudopotentials

International Nuclear Information System (INIS)

Abbas, T.

1982-06-01

Experiments were performed on the Ni-Ir alloys to measure the diffuse X-ray scattering intensity after annealing from high temperatures. It was established that the short-range order exists in these alloys when the samples are quenched from 1200 0 C and 1400 0 C. The ordering potentials for various concentrations of Ir in Ni were calculated using the pseudopotentials of Animalu. The method of incorporating the d electrons in the dielectric screening function was proposed. It was shown that the ordering potential is severely affected by the new type of screening. (author)

Validation of the thermal code of RadTherm-IR, IR-Workbench, and F-TOM

Science.gov (United States)

Schwenger, Frédéric; Grossmann, Peter; Malaplate, Alain

2009-05-01

System assessment by image simulation requires synthetic scenarios that can be viewed by the device to be simulated. In addition to physical modeling of the camera, a reliable modeling of scene elements is necessary. Software products for modeling of target data in the IR should be capable of (i) predicting surface temperatures of scene elements over a long period of time and (ii) computing sensor views of the scenario. For such applications, FGAN-FOM acquired the software products RadTherm-IR (ThermoAnalytics Inc., Calumet, USA; IR-Workbench (OKTAL-SE, Toulouse, France). Inspection of the accuracy of simulation results by validation is necessary before using these products for applications. In the first step of validation, the performance of both "thermal solvers" was determined through comparison of the computed diurnal surface temperatures of a simple object with the corresponding values from measurements. CUBI is a rather simple geometric object with well known material parameters which makes it suitable for testing and validating object models in IR. It was used in this study as a test body. Comparison of calculated and measured surface temperature values will be presented, together with the results from the FGAN-FOM thermal object code F-TOM. In the second validation step, radiances of the simulated sensor views computed by RadTherm-IR and IR-Workbench will be compared with radiances retrieved from the recorded sensor images taken by the sensor that was simulated. Strengths and weaknesses of the models RadTherm-IR, IR-Workbench and F-TOM will be discussed.

Preparation of flexible TiO2 photoelectrodes for dye-sensitized solar cells

Science.gov (United States)

Li, Wen-Ren; Wang, Hsiu-Hsuan; Lin, Chia-Feng; Su, Chaochin

2014-09-01

Dye-sensitized solar cells (DSSCs) based on nanocrystalline TiO2 photoelectrodes on indium tin oxide (ITO) coated polymer substrates have drawn great attention due to its lightweight, flexibility and advantages in commercial applications. However, the thermal instability of polymer substrates limits the process temperature to below 150 °C. In order to assure high and firm interparticle connection between TiO2 nanocrystals (TiO2-NC) and polymer substrates, the post-treatment of flexible TiO2 photoelectrodes (F-TiO2-PE) by mechanical compression was employed. In this work, Degussa P25 TiO2-NC was mixed with tert-butyl alcohol and DI-water to form TiO2 paste. F-TiO2-PE was then prepared by coating the TiO2 paste onto ITO coated polyethylene terephthalate (PET) substrate using doctor blade followed by low temperature sintering at 120 °C for 2 hours. To study the effect of mechanical compression, we applied 50 and 100 kg/cm2 pressure on TiO2/PET to complete the fabrication of F-TiO2-PE. The surface morphology of F-TiO2-PE was characterized using scanning electron microscopy. The resultant F-TiO2-PE sample exhibited a smooth, crack-free structure indicating the great improvement in the interparticle connection of TiO2-NC. Increase of compression pressure could lead to the increase of DSSC photoconversion efficiency. The best photoconversion efficiency of 4.19 % (open circuit voltage (Voc) = 0.79 V, short-circuit photocurrent density (Jsc) = 7.75 mA/cm2, fill factor (FF) = 0.68) was obtained for the F-TiO2-PE device, which showed great enhancement compared with the F-TiO2-PE cell without compression treatment. The effect of compression in DSSC performance was vindicated by the electrochemical impedance spectroscopy measurement.

Bioactivity studies on TiO{sub 2}-bearing Na{sub 2}O–CaO–SiO{sub 2}–B{sub 2}O{sub 3} glasses

Energy Technology Data Exchange (ETDEWEB)

Jagan Mohini, G. [Department of Physics, Andhra Loyola College, Vijayawada 520 008, Andhra Pradesh (India); Department of Physics, Acharya Nagarjuna University, Nagarjuna Nagar 522 510, A.P. (India); Sahaya Baskaran, G. [Department of Physics, Andhra Loyola College, Vijayawada 520 008, Andhra Pradesh (India); Ravi Kumar, V. [Department of Physics, Acharya Nagarjuna University, Nagarjuna Nagar 522 510, A.P. (India); Piasecki, M. [Institute of Physics, J. Dlugosz University, Al. Armii Krajowej 13/15, Czestochowa (Poland); Veeraiah, N., E-mail: nvr8@rediffmail.com [Department of Physics, Acharya Nagarjuna University, Nagarjuna Nagar 522 510, A.P. (India)

2015-12-01

Soda lime silica borate glasses mixed with different concentrations of TiO{sub 2} are synthesized by the melt-quenching technique. As a part of study on bioactivity of these glasses, the samples were immersed in simulated body fluid (SBF) solution for prolonged times (~ 21 days) during which weight loss along with pH measurements is carried out at specific intervals of time. The XRD and SEM analyses of post-immersed samples confirm the formation of crystalline hydroxyapatite layer (HA) on the surface of the samples. To assess the role of TiO{sub 2} on the formation of HA layer and degradability of the samples the spectroscopic studies viz. optical absorption and IR spectral studies on post- and pre-immersed samples have been carried out. The analysis of the results of degradability together with spectroscopic studies as a function of TiO{sub 2} concentration indicated that about 6.0 mol% of TiO{sub 2} is the optimal concentration for achieving better bioactivity of these glasses. The presence of the maximal concentration octahedral titanium ions in this glass that facilitates the formation of HA layer is found to be the reason for such a higher bioactivity. - Highlights: • Soda lime silica borate glasses mixed with TiO{sub 2} are synthesized. • Bioactivity of the glasses is studied by immersing them in SBF solution. • XRD and SEM studies indicated the formation of hydroxyapatite layer on the surface. • Quantum of degradability is the highest in the glasses mixed with 6.0 mol% of TiO{sub 2.} • The results are analyzed using IR and optical absorption studies.

Experimental Microkinetic Approach of De-NO x by NH 3 on V 2 O 5 /WO 3 /TiO 2 Catalysts. 4. Individual Heats of Adsorption of Adsorbed H 2 O Species on Sulfate-Free and Sulfated TiO 2 Supports

KAUST Repository

Giraud, Franç ois; Couble, Julien; Geantet, Christophe; Guilhaume, Nolven; Puzenat, Eric; Gros, Sé bastien; Porcheron, Lynda; Kanniche, Mohamed; Bianchi, Daniel

2015-01-01

© 2015 American Chemical Society. The present study is a part of an experimental microkinetic approach of the removal of NOx from coal-fired power plants by reduction with NH3 on V2O5/WO3/TiO2 catalysts (NH3-selective catalytic reduction, NH3-SCR). It is dedicated to the characterization of the heats of adsorption of molecularly adsorbed H2Oads species formed on sulfate-free and sulfated TiO2 supports. Water, which is always present during the NH3-SCR, may be in competition and/or react (formation of NH4⁺) with the adsorbed NH3 species controlling the coverage of the adsorbed intermediate species of the reaction. Mainly, an original experimental procedure named adsorption equilibrium infrared spectroscopy (AEIR) previously used for the adsorption of NH3 species on the same solids is adapted for the adsorption of H2O. At Ta = 300 K and for PH2 O ≤ 1 kPa, three main H2Oads species are formed (associated with a minor amount of dissociated H2O species) on the two TiO2 solids. The species are identified by the positions of their IR bands in the 3750-3000 cm^-1 range. Considering the decreasing order of stability, they are (a) coordinated to strong (L2) and weak (L1) Lewis sites and denoted H2O ads-L2 and H2Oads-L1, respectively, and (b) hydrogen bonded to the H2Oads-L species and on O^2-/OH sites of the solids (denoted H2Owads). The three species have a common well-defined δH2O IR band at a position in the range 1640-1610 cm^-1 according to the total coverage of the surface. According to the AEIR method, the evolution of the intensity of this IR band during the increase in the adsorption temperature Ta in isobaric condition provides the evolution of the average coverage of the three species and then to their individual heats of adsorption as a function of their coverage. It is shown that there are no significant differences on the two TiO2 solids. In particular, the heat of adsorption of the H2Oads-L2 species varies from �

Experimental Microkinetic Approach of De-NO x by NH 3 on V 2 O 5 /WO 3 /TiO 2 Catalysts. 4. Individual Heats of Adsorption of Adsorbed H 2 O Species on Sulfate-Free and Sulfated TiO 2 Supports

KAUST Repository

Giraud, François

2015-07-16

© 2015 American Chemical Society. The present study is a part of an experimental microkinetic approach of the removal of NOx from coal-fired power plants by reduction with NH3 on V2O5/WO3/TiO2 catalysts (NH3-selective catalytic reduction, NH3-SCR). It is dedicated to the characterization of the heats of adsorption of molecularly adsorbed H2Oads species formed on sulfate-free and sulfated TiO2 supports. Water, which is always present during the NH3-SCR, may be in competition and/or react (formation of NH4⁺) with the adsorbed NH3 species controlling the coverage of the adsorbed intermediate species of the reaction. Mainly, an original experimental procedure named adsorption equilibrium infrared spectroscopy (AEIR) previously used for the adsorption of NH3 species on the same solids is adapted for the adsorption of H2O. At Ta = 300 K and for PH2 O ≤ 1 kPa, three main H2Oads species are formed (associated with a minor amount of dissociated H2O species) on the two TiO2 solids. The species are identified by the positions of their IR bands in the 3750-3000 cm^-1 range. Considering the decreasing order of stability, they are (a) coordinated to strong (L2) and weak (L1) Lewis sites and denoted H2O ads-L2 and H2Oads-L1, respectively, and (b) hydrogen bonded to the H2Oads-L species and on O^2-/OH sites of the solids (denoted H2Owads). The three species have a common well-defined δH2O IR band at a position in the range 1640-1610 cm^-1 according to the total coverage of the surface. According to the AEIR method, the evolution of the intensity of this IR band during the increase in the adsorption temperature Ta in isobaric condition provides the evolution of the average coverage of the three species and then to their individual heats of adsorption as a function of their coverage. It is shown that there are no significant differences on the two TiO2 solids. In particular, the heat of adsorption of the H2Oads-L2 species varies from �

Enhanced photomechanical response of a Ni-Ti shape memory alloy coated with polymer-based photothermal composites

Science.gov (United States)

Perez-Zúñiga, M. G.; Sánchez-Arévalo, F. M.; Hernández-Cordero, J.

2017-10-01

A simple way to enhance the activation of shape memory effects with light in a Ni-Ti alloy is demonstrated. Using polydimethylsiloxane-carbon nanopowder (PDMS+CNP) composites as coatings, the one-way shape memory effect (OWSME) of the alloy can be triggered using low power IR light from a laser diode. The PDMS+CNP coatings serve as photothermal materials capable to absorb light, and subsequently generate and dissipate heat in a highly efficient manner, thereby reducing the optical powers required for triggering the OWSME in the Ni-Ti alloy. Experimental results with a cantilever flexural test using both, bare Ni-Ti and coated samples, show that the PDMS+CNP coatings perform as thermal boosters, and therefore the temperatures required for phase transformation in the alloy can be readily obtained with low laser powers. It is also shown that the two-way shape memory effect (TWSME) can be set in the Ni-Ti alloy through cycling the TWSME by simply modulating the laser diode signal. This provides a simple means for training the material, yielding a light driven actuator capable to provide forces in the mN range. Hence, the use of photothermal coatings on Ni-Ti shape memory alloys may offer new possibilities for developing light-controlled smart actuators.

Osteogenic potential of a novel microarc oxidized coating formed on Ti6Al4V alloys

Science.gov (United States)

Wang, Yaping; Lou, Jin; Zeng, Lilan; Xiang, Junhuai; Zhang, Shufang; Wang, Jun; Xiong, Fucheng; Li, Chenglin; Zhao, Ying; Zhang, Rongfa

2017-08-01

In order to improve the biocompatibility, Ti6Al4V alloys are processed by micro arc oxidation (MAO) in a novel electrolyte of phytic acid, a natural organic phosphorus-containing matter. The MAO coatings were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Fourier Transform Infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS). The cytocompatibility of Ti6A14V alloys before and after MAO were comprehensively evaluated. The results showed that the fabricated MAO coatings were composed of rutile, anatase, TiP2O7 as well as some OH- groups, exhibiting the excellent hydrophilicity and a porous structure with small micro pores. No cytotoxicity towards MC3T3-E1cells was observed in this study. In particular, MAO treated Ti6Al4V alloys presented comparable cell adhesion and proliferation as well as significantly enhanced alkaline phosphatase activity, extracellular matrix (ECM) mineralization and collagen secretion in comparison with the untreated control. The results suggest that the Ti6Al4V alloys treated by MAO in phytic acid can be used as implants for orthopaedic applications, providing a simple and practical method to widen clinical acceptance of titanium alloys.

Isothermal section of the Ti-Si-B system at 1250 ° C in the Ti-TiSi2-TiB2 region

OpenAIRE

Ramos, Alfeu Saraiva; Baldan, Renato; Nunes, Carlos Angelo; Coelho, Gilberto Carvalho; Suzuki, Paulo Atsushi; Rodrigues, Geovani

2013-01-01

A partial isothermal section (Ti-TiSi2-TiB2 region) of the ternary Ti-Si-B system at 1250 ° C was determined from heat-treated alloys prepared via arc melting. Microstructural characterization has been carried out through scanning electron microscopy (SEM), x-ray diffraction (xRD) and wavelength dispersive spectrometry (WDS). The results have shown the stability of the near stoichiometric Ti6Si2B phase and a negligible solubility of boron in the Ti-silicides as well as of Si in the Ti-borides...

Traceable calibration of hospital 192Ir HDR sources

International Nuclear Information System (INIS)

Govinda Rajan, K.N.; Bhatt, B.C.; Pendse, A.M.; Kannan, V.

2002-01-01

Presently, no primary standard exists for the standardization of remote afterloading 192 Ir HDR sources. These sources are, therefore, being standardized by a few Secondary Standard Dosimetry Laboratories (SSDLs), in terms of Air Kerma Strength (AKS) or Reference Air Kerma Rate (RAKR) using a 0.6 cc Farmer type chamber, set up as an Interim Standard. These SSDLs offer calibration to well type of ionization chambers that are normally used by the hospitals for calibrating the 192 lr HDR source. Presently, in many countries, including India, well chambers are not commercially available. Nor do these countries offer any calibration service for 192 lr HDR source. With the result users make use of well chambers imported from different countries with their calibration traceable to the country of origin. Since no intercomparisons between these countries have been reported, the measurement consistency between hospitals becomes questionable. The problem is compounded by the fact that these chambers are used for several years without re-calibration since no calibration service is locally available. For instance, in India, the chambers have been in use in hospitals, since 1994, without a second calibration. Not all hospitals use the well chamber for the calibration of the 192 lr HDR source. Many hospitals make use of 0.6 cc chambers, in air, at short source to chamber distances, for measuring the AKS of the source. The latter method is prone to much larger inaccuracy due to the use of very short source to chamber distances without proper calibration jigs, use of 60 Co calibration factor for 192 Ir HDR source calibrations, neglecting correction factors for room scatter, fluence non-uniformity, use of arbitrary buildup factors for the buildup cap of the chamber etc. A comparison of the procedures used at hospitals revealed that various arbitrary methods are in use at hospitals. An indigenously developed well chamber was calibrated against a Reference Standard traceable to the

Al-doped TiO{sub 2} mesoporous material supported Pd with enhanced catalytic activity for complete oxidation of ethanol

Energy Technology Data Exchange (ETDEWEB)

Zhu, Jing, E-mail: mlczjsls123@163.com; Mu, Wentao, E-mail: mwt15035687833@163.com; Su, Liqing, E-mail: suliqing0163@163.com; Li, Xingying, E-mail: lixingying0479@link.tyut.edu.cn; Guo, Yuyu, E-mail: guoyuyu0455@link.tyut.edu.cn; Zhang, Shen, E-mail: zhangshen0472@link.tyut.edu.cn; Li, Zhe, E-mail: lizhe@tyut.edu.cn

2017-04-15

Pd catalysts supported on Al-doped TiO{sub 2} mesoporous materials were evaluated in complete oxidation of ethanol. The catalysts synthesized by wet impregnation based on evaporation-induced self-assembly were characterized by X-ray diffraction, measurement of pore structure, XPS, FT-IR, temperature programmed reduction and TEM. Characteristic results showed that the aluminium was doped into the lattice of mesoporous anatase TiO{sub 2} to form Al-O-Ti defect structure. Catalytic results revealed that Al-doped catalysts were much more active than the pristine one, especially at low temperature (≤200 °C). This should be ascribed to the introduction of aluminium ions that suppressed the strong metal-support interaction and increased the active sites of Pd oxides, enhanced the stabilized anatase TiO{sub 2}, improved well dispersed high valence palladium species with high reducibility and enriched chemisorption oxygen. - Graphical abstract: Al-doped Pd/TiO{sub 2} exhibited optimal catalytic performance for ethanol oxidation and CO{sub 2} yield by the suppression of SMSI. - Highlights: • Palladium catalysts supported on Al-doped TiO{sub 2} mesoporous materials were studied. • The introduction of Al can enhance anatase stabilization and increase defect TiO{sub 2}. • The Pd/Al-TiO{sub 2} catalysts show higher ethanol conversion and CO{sub 2} yield than Pd/TiO{sub 2}. • The influence of Al on SMSI and catalytic performance were evaluated by TPR and XPS.

Preparation of poly-o-phenylenediamine/TiO2/fly-ash cenospheres and its photo-degradation property on antibiotics

International Nuclear Information System (INIS)

Huo Pengwei; Yan Yongsheng; Li Songtian; Li Huaming; Huang Weihong

2010-01-01

A series of poly-o-phenylenediamine/TiO 2 /fly-ash cenospheres(POPD/TiO 2 /fly-ash cenospheres) composites have been prepared from o-phenylenediamine and TiO 2 /fly-ash cenospheres under various polymerization conditions. The properties of the samples were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), specific surface area (BET), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and UV-vis diffuse reflectance spectrum (UV-vis DRS). Photocatalytic activity was studied by degradation of antibiotics waste water under visible light. The results indicate that the photo-induced method is viable for preparing modified photocatalysts, and the modified photocatalysts have good absorption in visible light range. The photocatalysts of POPD/TiO 2 /fly-ash cenospheres which have good performance are prepared at pH 3 and 4, and the polymerized time around 40 min. When the photocatalysts are prepared under the conditions of pH 3 and polymerized time 40 min, the degradation rate of roxithromycin waste water could reach near 60%, and it indicates that the way of POPD modified TiO 2 /fly-ash cenospheres to degrade the antibiotics waste water is viable.

(Nd0⋅065Ti0⋅87Nb0⋅065)O3 ceramic

Indian Academy of Sciences (India)

Unknown

Polycrystalline ceramic samples of sodium bismuth titanate with simultaneous doping at A and B sites have been studied for the influence of ... of Nd and Nb at B site in BaTiO3 (BaNdxTi1–2xNbxO3). (Mahboob et al 2005a). Dielectric ..... hence the conduction arises due to short range translation hopping via large polarons.

Temperature-dependent optical absorption of SrTiO3

International Nuclear Information System (INIS)

Kok, Dirk J.; Irmscher, Klaus; Naumann, Martin; Guguschev, Christo; Galazka, Zbigniew; Uecker, Reinhard

2015-01-01

The optical absorption edge and near infrared absorption of SrTiO 3 were measured at temperatures from 4 to 1703 K. The absorption edge decreases from 3.25 eV at 4 K to 1.8 eV at 1703 K and is extrapolated to approximately 1.2 eV at the melting point (2350 K). The transmission in the near IR decreases rapidly above 1400 K because of free carrier absorption and is about 50% of the room temperature value at 1673 K. The free carriers are generated by thermal excitation of electrons over the band gap and the formation of charged vacancies. The observed temperature-dependent infrared absorption can be well reproduced by a calculation based on simple models for the intrinsic free carrier concentration and the free carrier absorption coefficient. The measured red shift of the optical absorption edge and the rising free carrier absorption strongly narrow the spectral range of transmission and impede radiative heat transport through the crystal. These effects have to be considered in high temperature applications of SrTiO 3 -based devices, as the number of free carriers rises considerably, and in bulk crystal growth to avoid growth instabilities. Temperature dependent optical absorption edge of SrTiO 3 , measured, fitted, and extrapolated to the melting point. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Preparation of Ti3Al intermetallic compound by spark plasma sintering

Science.gov (United States)

Ito, Tsutomu; Fukui, Takahiro

2018-04-01

Sintered compacts of single phase Ti3Al intermetallic compound, which have excellent potential as refractory materials, were prepared by spark plasma sintering (SPS). A raw powder of Ti3Al intermetallic compound with an average powder diameter of 176 ± 56 μm was used in this study; this large powder diameter is disadvantageous for sintering because of the small surface area. The samples were prepared at sintering temperatures (Ts) of 1088, 1203, and 1323 K, sintering stresses (σs) of 16, 32, and 48 MPa, and a sintering time (ts) of 10 min. The calculated relative densities based on the apparent density of Ti3Al provided by the supplier were approximately 100% under all sintering conditions. From the experimental results, it was evident that SPS is an effective technique for dense sintering of Ti3Al intermetallic compounds in a short time interval. In this report, the sintering characteristics of Ti3Al intermetallic compacts are briefly discussed and compared with those of pure titanium compacts.

TiO2 nanoparticles immobilized on carbon nanotubes for enhanced visible-light photo-induced activity

Directory of Open Access Journals (Sweden)

Ali Akbar Ashkarran

2015-04-01

Full Text Available CNT–TiO2 nanocomposites were prepared through (i simple mixing of as prepared CNTs and TiO2 nanoparticles (NPs, (ii simple mixing of as prepared CNTs and TiO2 NPs followed by heat treatment and (iii simple mixing of as prepared CNTs and TiO2 NPs followed by UV illumination. The synthesis of CNTs and TiO2 NPs were performed individually by arc discharge in water and sol–gel methods, respectively and characterized by X-ray diffraction (XRD, ultra violet and visible spectroscopy (UV–vis, Fourier transform infrared spectroscopy (FT-IR, scanning electron microscopy (SEM and transmission electron microscopy (TEM. The visible-light photocatalytic performance of CNT–TiO2 nanocomposites was successfully demonstrated for the degradation of Rhodamine B (Rh. B as a model dye at room temperature. It is found that CNT–TiO2 nanocomposites extended the light absorption spectrum toward the visible region and considerably improved the photocatalytic efficiency under visible-light irradiation. The visible-light photocatalytic activities of CNT–TiO2 nanocomposites in which CNTs are produced by arc discharge in deionized (DI water at 40, 60 and 80 A arc currents and combined through three different protocols are also investigated. It was found that samples prepared at 80 A arc current and 5 s arc duration followed by UV illumination revealed best photocatalytic activity compared with the same samples prepared under simple mixing and simple mixing followed by heat treatment. The enhancement in the photocatalytic property of CNT–TiO2 nanocomposites prepared at 80 A arc current followed by UV illumination may be ascribed to the quality of CNTs produced at this current, as was reported before.

STATYBINIŲ MEDŽIAGŲ KONKURENCINGUMAS IR TENDENCIJOS

OpenAIRE

Kontrimas, Robertas

2010-01-01

Darbe analizuojamas statybinių medžiagų konkurencingumas, nustatyti statybinių medžiagų konkurencingumą įtakojantys veiksniai ir pateikti pasiūlymai rinkos gerinimui. Pasitvirtino hipotezė, kad statybinių medžiagų paklausą ir kainas įtakoja klientų poreikiai ir jų finansinės galimybės, tačiau pasaulinės krizės įtaka yra labai ženkli,. Atlikta darbuotojų ir pirkėjų apklausa padėjo nustatyti, kokios statybinės medžiagos dažniausiai yra perkamos, kaip klientai ir darbuotojai vertina įmonę ir jos...

Mesoporous CeTiSiMCM-48 as novel photocatalyst for degradation of organic compounds

International Nuclear Information System (INIS)

Mureseanu, Mihaela; Parvulescu, Viorica; Radu, Teodora; Filip, Mihaela; Carja, Gabriela

2015-01-01

This work presents novel photocatalysts containing Ti and/or Ce embedded in the mesoporous silica framework (TiSiMCM-48, CeSiMCM-48 and CeTiSiMCM-48) that were prepared via a facile sol–gel process in the presence of ionic structure directing agents. The structural properties of the obtained materials were analyzed by X-ray diffraction (XRD), nitrogen adsorption-desorption, scanning and transmission electron microscopy (SEM, TEM), EDAX analysis, X-ray photoelectron microscopy (XPS), ultraviolet–visible diffuse reflectance spectroscopy (UV–vis DRS) and Fourier transformation infrared spectroscopy (FT-IR). The results indicated that Ce and Ti were highly dispersed or incorporated into the framework of the cubic SiMCM-48, with an enhanced light-trapping effect both in the UV and Vis regions. When applied to the photocatalytic degradation of phenol, the best results were obtained for the bimetallic hybrid. The best activity of CeTiSiMCM-48 photocatalyst was ascribed to improved electron–hole pair separation efficiency and formation of more reactive oxygen species due to the presence of Ce 4+ /Ce 3+ . The mesoporous support increases the dispersability of the photoactive Ti 4+ or Ce 4+ /Ce 3+ species on the catalyst surface and the accessibility of the substrate to the active sites. Furthermore, the catalysts can be easily recovered and reused for four cycles without significant loss of activity. - Highlights: • Novel photocatalysts containing Ti and/or Ce embedded in the mesoporous MCM-48 silica. • Ce 4+ /Ce 3+ improved electron–hole pair separation and reactivity of oxygen species. • The mesoporous support increases the dispersability of the photoactive species. • The photocatalyst was highly active and stable for phenol degradation under UV irradiation. • TiCeSiMCM-48 can be recycled up to four cycles without significant loss of activity

Carbon and TiO{sub 2} synergistic effect on methylene blue adsorption

Energy Technology Data Exchange (ETDEWEB)

Simonetti, Evelyn Alves Nunes, E-mail: evelynalvesnunes@yahoo.com.br; Simone Cividanes, Luciana de; Campos, Tiago Moreira Bastos; Rossi Canuto de Menezes, Beatriz; Brito, Felipe Sales; Thim, Gilmar Patrocínio

2016-07-01

Due to its high efficiency, low cost and a simple operation, the adsorption process is an important and widely used technique for industrial wastewater treatment. Recent studies on the removal of artificial dyes by adsorption include a large number of adsorbents, such as: activated carbon, silicates, carbon nanotube, graphene, fibers, titanates and doped titanates. The carbon insertion in the TiO{sub 2} structure promotes a synergistic effect on the adsorbent composite, improving the adsorption and the charge-transfer efficiency rates. However, there are few studies regarding the adsorption capacity of TiO{sub 2}/Carbon composites with the carbon concentration. This study evaluates the effect of carbon (resorcinol/formaldehyde) insertion on TiO{sub 2} structure through the adsorption process. Adsorbents were prepared by varying the carbon weight percentages using the sol-gel method. The physicochemical properties of the catalysts prepared, such as crystallinity, particle size, surface morphology, specific surface area and pore volume were investigated. The kinetic study, adsorption isotherm, pH effect and thermodynamic study were examined in batch experiments using methylene blue as organic molecule. In addition, the effect of carbon phase on the adsorption capacity of TiO{sub 2}-carbon composite was deeply investigated. SEM micrographs showed that TiO{sub 2} phase grows along the carbon phase and FT-IR results showed the presence of Ti−O−C chemical bonding. The experiments indicate that the carbon phase acted as a nucleation agent for the growth of TiO{sub 2} during the sol-gel step, with a TiO{sub 2} structure suitable for blue methylene adsorption, resulting in a material with large surface area and slit-like or wedge-shaped pores. Further experiments will show the best carbon concentration for methylene blue adsorption using a TiO{sub 2} based material. - Highlights: • This article deals with the adsorption of methylene blue onto TiO{sub 2}-Carbon

Phase stability and decomposition processes in Ti-Al based intermetallics

Energy Technology Data Exchange (ETDEWEB)

Nakai, Kiyomichi [Department of Materials Science and Engineering, Faculty of Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama 790 (Japan); Ono, Toshiaki [Department of Materials Science and Engineering, Faculty of Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama 790 (Japan); Ohtsubo, Hiroyuki [Department of Materials Science and Engineering, Faculty of Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama 790 (Japan); Ohmori, Yasuya [Department of Materials Science and Engineering, Faculty of Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama 790 (Japan)

1995-02-28

The high-temperature phase equilibria and the phase decomposition of {alpha} and {beta} phases were studied by crystallographic analysis of the solidification microstructures of Ti-48at.%Al and Ti-48at.%Al-2at.%X (X=Mn, Cr, Mo) alloys. The effects on the phase stability of Zr and O atoms penetrating from the specimen surface were also examined for Ti-48at.%Al and Ti-50at.%Al alloys. The third elements Cr and Mo shift the {beta} phase region to higher Al concentrations, and the {beta} phase is ordered to the {beta}{sub 2} phase. The Zr and O atoms stabilize {beta} and {alpha} phases respectively. In the Zr-stabilized {beta} phase, {alpha}{sub 2} laths form with accompanying surface relief, and stacking faults which relax the elastic strain owing to lattice deformation are introduced after formation of {alpha}{sub 2} order domains. Thus shear is thought to operate after the phase transition from {beta} to {alpha}{sub 2} by short-range diffusion. A similar analysis was conducted for the Ti-Al binary system, and the transformation was interpreted from the CCT diagram constructed qualitatively. ((orig.))

Fabrication and Mechanical Properties of TiC/TiAl Composites

Institute of Scientific and Technical Information of China (English)

YUE Yun-long; GONG Yan-sheng; WU Hai-tao; WANG Chuan-bin; ZHANG Lian-meng

2004-01-01

TiC/TiAl composites with different TiC content were fabricated by rapid heating technique ofspark plasma sintering (SPS). The effect of TiC particles on microstructure and mechanical properties of TiAl matrix was investigated. The results indicate that grain sizes of TiAl matrix decrease and mechanical properties are improved because of the addition of TiC particles. The composites display a 26.8% increase in bending strength when10wt% TiC is added and 43.8% improvement in fracture toughness when 5 wt % TiC is added compared to valuesof TiC-free materials. Grain-refinement and dispersion-strengthening were the main strengthening mechanism. Theimprovement of fracture toughness was due to the deflexion of TiC particles to the crack.

Interconnected TiO2 Nanowire Networks for PbS Quantum Dot Solar Cell Applications

Directory of Open Access Journals (Sweden)

Fan Xu

2012-01-01

Full Text Available We present a simple method for the fabrication of an interconnected porous TiO2 nanostructured film via dip coating in a colloidal suspension of ultrathin TiO2 nanowires followed by high-temperature annealing. The spheroidization of the nanowires and the fusing of the loosely packed nanowire films at the contact points lead to the formation of nanopores. Using this interconnected TiO2 nanowire network for electron transport, a PbS/TiO2 heterojunction solar cell with a large short-circuit current of 2.5 mA/cm2, a Voc of 0.6 V, and a power conversion efficiency of 5.4% is achieved under 8.5 mW/cm2 white light illumination. Compared to conventional planar TiO2 film structures, these results suggest superior electron transport properties while still providing the large interfacial area between PbS quantum dots and TiO2 required for efficient exciton dissociation.

Study on the enhanced adsorption properties of lysozyme on polyacrylic acid modified TiO2 nano-adsorbents

Science.gov (United States)

Liu, Yufeng; Jin, Zu; Meng, Hao; Zhang, Xia

2018-01-01

The adsorption and immobilization of enzymes onto solid carriers has been focused on due to their many advantages, such as improved stability against a thermal or organic solvent and a good cycle usability. TiO2 nanoparticles is one of excellent nano-adsorbents owing to its excellent biocompatibility, non-inflammatory, and abundant surface hydroxyl groups, which are convenient to be combined with various functional groups. In this paper polyacrylic acid (PAA) modified TiO2 nanoparticles were synthesized through an in situ light-induced polymerization of acrylic acid on the surface of TiO2 nanoparticles. The structure and surface physicochemical properties of the PAA/TiO2 nanoparticles were characterized by TEM, XRD, FT-IR, Zeta potential measurements and TG-DSC. The experimental results showed that the isoelectric point of PAA/TiO2 significantly reduced to 1.82 compared with that of pure TiO2 nanoparticles (6.08). In the adsorption tests of lysozyme (Lyz), the PAA/TiO2 nanoparticles displayed enhanced adsorption activity compared with pristine TiO2. The maximum adsorption capacity of PAA/TiO2 for Lyz was 225.9 mg g-1 under the optimum conditions where the initial concentration of Lyz was 300 mg ml-1, the addition amount of PAA/TiO2 was 6.4 mg, the adsorption time was 30 min and the pH value was 7.0. The sodium dodecyl sulfate (SDS, 0.5%) presented the best efficiency (76.86%) in the removal of adsorbed Lyz, and the PAA/TiO2 nanoparticles showed excellent adsorption stability based on five cyclic adsorption-desorption tests. The fitting calculation results of the adsorption isotherm and the thermodynamics indicated the adsorption was an exothermic, entropy increasing, spontaneous and monomolecular layer adsorption process.

Discrimination of Chinese Sauce liquor using FT-IR and two-dimensional correlation IR spectroscopy

Science.gov (United States)

Sun, Su-Qin; Li, Chang-Wen; Wei, Ji-Ping; Zhou, Qun; Noda, Isao

2006-11-01

We applied the three-step IR macro-fingerprint identification method to obtain the IR characteristic fingerprints of so-called Chinese Sauce liquor (Moutai liquor and Kinsly liquor) and a counterfeit Moutai. These fingerprints can be used for the identification and discrimination of similar liquor products. The comparison of their conventional IR spectra, as the first step of identification, shows that the primary difference in Sauce liquor is the intensity of characteristic peaks at 1592 and 1225 cm -1. The comparison of the second derivative IR spectra, as the second step of identification, shows that the characteristic absorption in 1400-1800 cm -1 is substantially different. The comparison of 2D-IR correlation spectra, as the third and final step of identification, can discriminate the liquors from another direction. Furthermore, the method was successfully applied to the discrimination of a counterfeit Moutai from the genuine Sauce liquor. The success of the three-step IR macro-fingerprint identification to provide a rapid and effective method for the identification of Chinese liquor suggests the potential extension of this technique to the identification and discrimination of other wine and spirits, as well.

Chemical synthesis of CdS onto TiO2 nanorods for quantum dot sensitized solar cells

Science.gov (United States)

Pawar, Sachin A.; Patil, Dipali S.; Lokhande, Abhishek C.; Gang, Myeng Gil; Shin, Jae Cheol; Patil, Pramod S.; Kim, Jin Hyeok

2016-08-01

A quantum dot sensitized solar cell (QDSSC) is fabricated using hydrothermally grown TiO2 nanorods and successive ionic layer adsorption and reaction (SILAR) deposited CdS. Surface morphology of the TiO2 films coated with different SILAR cycles of CdS is examined by Scanning Electron Microscopy which revealed aggregated CdS QDs coverage grow on increasing onto the TiO2 nanorods with respect to cycle number. Under AM 1.5G illumination, we found the TiO2/CdS QDSSC photoelectrode shows a power conversion efficiency of 1.75%, in an aqueous polysulfide electrolyte with short-circuit photocurrent density of 4.04 mA/cm2 which is higher than that of a bare TiO2 nanorods array.

Sol-gel synthesis of TiO{sub 2}-SiO{sub 2} photocatalyst for {beta}-naphthol photodegradation

Energy Technology Data Exchange (ETDEWEB)

Qourzal, S., E-mail: samir_qourzal@yahoo.fr [Equipe de Materiaux Photocatalyse et Environnement, Departement de Chimie, Faculte des Sciences, Universite Ibn Zohr, B. P. 8106 Cite Dakhla, Agadir (Morocco); Barka, N.; Tamimi, M.; Assabbane, A. [Equipe de Materiaux Photocatalyse et Environnement, Departement de Chimie, Faculte des Sciences, Universite Ibn Zohr, B. P. 8106 Cite Dakhla, Agadir (Morocco); Nounah, A. [Ecole Superieure de Technologie, Avenue Prince Heritier Sidi Mohamed, B. P. 227, Sale-Medina (Morocco); Ihlal, A. [Laboratoire de Physique des Semi-conducteurs et Energie Solaire, Departement de Physique, Faculte, des Sciences, Universite Ibn Zohr, B. P. 8106 Cite Dakhla, Agadir (Morocco); Ait-Ichou, Y. [Equipe de Materiaux Photocatalyse et Environnement, Departement de Chimie, Faculte des Sciences, Universite Ibn Zohr, B. P. 8106 Cite Dakhla, Agadir (Morocco)

2009-06-01

Silica gel supported titanium dioxide particles (TiO{sub 2}-SiO{sub 2}) prepared by sol-gel method was as photocatalyst in the degradation of {beta}-naphthol in water under UV-illumination. The prepared sample has been characterized by powder X-ray diffraction (XRD), infrared spectroscopy (IR) and scanning electron microscopy (SEM). The supported catalyst had large surface area and good sedimentation ability. The photodegradation rate of {beta}-naphthol under UV-irradiation depended strongly on adsorption capacity of the catalyst, and the photoactivity of the supported catalyst was much higher than that of the pure titanium dioxides. The experiments were measured by high performance liquid chromatography (HPLC). The photodegradation rate of {beta}-naphthol using 60% TiO{sub 2}-SiO{sub 2} particles was faster than that using TiO{sub 2} 'Degussa P-25', TiO{sub 2} 'PC-50' and TiO{sub 2} 'Aldrich' as photocatalyst by 2.7, 4 and 7.8 times, respectively. The kinetics of photocatalytic {beta}-naphthol degradation was found to follow a pseudo-first-order rate law. The effect of the TiO{sub 2} loading on the photoactivity of TiO{sub 2}-SiO{sub 2} particles was also discussed. With good photocatalytic activity under UV-irradiation and the ability to be readily separated from the reaction system, this novel kind of catalyst exhibited the potential effective in the treatment of organic pollutants in aqueous systems.

Photocatalytic degradation of some organic dyes under solar light irradiation using TiO2 and ZnO nanoparticles

Directory of Open Access Journals (Sweden)

Mojtaba Amini

2016-01-01

Full Text Available Nanoparticles of the ZnO and TiO2 were synthesized and the physicochemical properties of the compounds were characterized by IR, X-ray diffraction (XRD, scanning electron microscopy (SEM and transmission electron microscopy (TEM. The XRD patterns of the ZnO and TiO2 nanoparticles could be indexed to hexagonal and rutile phase, respectively. Aggregated nanoparticles of ZnO and TiO2 with spherical-like shapes were observed with particle diameter in the range of 80-100 nm. These nanoparticles were used for photocatalytic degradation of various dyes, Rhodamine B (RhB, Methylene blue (MB and Acridine orange (AO under solar light irradiation at room temperature. Effect of the amount of catalyst on the rate of photodegradation was investigated. In general, because ZnO is unstable, due to incongruous dissolution to yield Zn(OH2 on the ZnO particle surfaces and thus leading to catalyst inactivation,the catalytic activity of the system for photodegradation of dyes decreased dramatically when TiO2 was replaced by ZnO.

Synthesis and characterization of TiO2/Ag/polymer ternary nanoparticles via surface-initiated atom transfer radical polymerization

International Nuclear Information System (INIS)

Park, Jung Tae; Koh, Joo Hwan; Seo, Jin Ah; Cho, Yong Soo; Kim, Jong Hak

2011-01-01

We report on the novel ternary hybrid materials consisting of semiconductor (TiO 2 ), metal (Ag) and polymer (poly(oxyethylene methacrylate) (POEM)). First, a hydrophilic polymer, i.e. POEM, was grafted from TiO 2 nanoparticles via the surface-initiated atom transfer radical polymerization (ATRP) technique. These TiO 2 -POEM brush nanoparticles were used to template the formation of Ag nanoparticles by introduction of a AgCF 3 SO 3 precursor and a NaBH 4 aqueous solution for reduction process. Successful grafting of polymeric chains from the surface of TiO 2 nanoparticles and the in situ formation of Ag nanoparticles within the polymeric chains were confirmed using transmission electron microscopy (TEM), UV-vis spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). FT-IR spectroscopy also revealed the specific interaction of Ag nanoparticles with the C=O groups of POEM brushes. This study presents a simple route for the in situ synthesis of both metal and polymer confined within the semiconductor, producing ternary hybrid inorganic-organic nanomaterials.

Effect of RGD Peptide-Coated TiO2 Nanotubes on the Attachment, Proliferation, and Functionality of Bone-Related Cells

Directory of Open Access Journals (Sweden)

Seunghan Oh

2013-01-01

Full Text Available The purpose of this research was to characterize an Arg-Gly-Asp (RGD peptide immobilized on TiO2 nanotubes. In addition, we investigated the effects of the RGD peptide-coated TiO2 nanotubes on the cellular response, proliferation, and functionality of osteogenic-induced human mesenchymal stem cells (hMSCs, which are osteoclasts that have been induced by bone marrow macrophages. The RGD peptide was grafted covalently onto the surface of TiO2 nanotubes based on the results of SEM, FT-IR, and XPS. Furthermore, the RGD peptide promoted the initial attachment and proliferation of the hMSCs, regardless of the size of the TiO2 nanotubes. However, the RGD peptide did not prominently affect the osteogenic functionality of the hMSCs because the peptide suppressed hMSC motility associated with osteogenic differentiation. The result of an in vitro osteoclast test showed that the RGD peptide accelerated the initial attachment of preosteoclasts and the formation of mature osteoclasts, which could resorb the bone matrix. Therefore, we believe that an RGD coating on TiO2 nanotubes synthesized on Ti implants might not offer significant acceleration of bone formation in vivo because osteoblasts and osteoclasts reside in the same compartment.

Complete Chloroplast Genome of Pinus massoniana (Pinaceae): Gene Rearrangements, Loss of ndh Genes, and Short Inverted Repeats Contraction, Expansion.

Science.gov (United States)

Ni, ZhouXian; Ye, YouJu; Bai, Tiandao; Xu, Meng; Xu, Li-An

2017-09-11

The chloroplast genome (CPG) of Pinus massoniana belonging to the genus Pinus (Pinaceae), which is a primary source of turpentine, was sequenced and analyzed in terms of gene rearrangements, ndh genes loss, and the contraction and expansion of short inverted repeats (IRs). P. massoniana CPG has a typical quadripartite structure that includes large single copy (LSC) (65,563 bp), small single copy (SSC) (53,230 bp) and two IRs (IRa and IRb, 485 bp). The 108 unique genes were identified, including 73 protein-coding genes, 31 tRNAs, and 4 rRNAs. Most of the 81 simple sequence repeats (SSRs) identified in CPG were mononucleotides motifs of A/T types and located in non-coding regions. Comparisons with related species revealed an inversion (21,556 bp) in the LSC region; P. massoniana CPG lacks all 11 intact ndh genes (four ndh genes lost completely; the five remained truncated as pseudogenes; and the other two ndh genes remain as pseudogenes because of short insertions or deletions). A pair of short IRs was found instead of large IRs, and size variations among pine species were observed, which resulted from short insertions or deletions and non-synchronized variations between "IRa" and "IRb". The results of phylogenetic analyses based on whole CPG sequences of 16 conifers indicated that the whole CPG sequences could be used as a powerful tool in phylogenetic analyses.

Epoxidation of limonene over Ti MCM 41 and Ti BETA

International Nuclear Information System (INIS)

Cubillos Lobo, Jairo Antonio; Gonzalez Rodriguez, Lina Maria; Montes de Correa, Consuelo

2002-01-01

Ti MCM 41 were synthesized and evaluated in the epoxidation of limonene, using peroxide of hydrogen (H 2 O) as agent oxidizer. The characteristic hexagonal phase of Ti MCM 41 was obtained by heating the precursor gel during three days at 100 centigrade degrees. Further heating up to ten days leads to a decrease of this phase. The increase (Ti) in the synthesis gel also decreases that phase. The increase of Ti in the synthesis gel also decreases that phase UV VIS and FTIR spectroscopy indicates that Ti was incorporated in the lattice of Ti MCM 41 as well as, in Ti BETA. SEM micrographs of Ti MCM 41 show that the morphology changes with the Ti loading. Ti MCM 41 was most active than Ti BETA for limonene epoxidation even though both show high selectivity to epoxides

The Introduction of an Undergraduate Interventional Radiology (IR) Curriculum: Impact on Medical Student Knowledge and Interest in IR

International Nuclear Information System (INIS)

Shaikh, M.; Shaygi, B.; Asadi, H.; Thanaratnam, P.; Pennycooke, K.; Mirza, M.; Lee, M.

2016-01-01

IntroductionInterventional radiology (IR) plays a vital role in modern medicine, with increasing demand for services, but with a shortage of experienced interventionalists. The aim of this study was to determine the impact of a recently introduced IR curriculum on perception, knowledge, and interest of medical students regarding various aspects of IR.MethodsIn 2014, an anonymous web-based questionnaire was sent to 309 4th year medical students in a single institution within an EU country, both before and after delivery of a 10-h IR teaching curriculum.ResultsSeventy-six percent (236/309) of the respondents participated in the pre-IR module survey, while 50 % (157/309) responded to the post-IR module survey. While 62 % (147/236) of the respondents reported poor or no knowledge of IR compared to other medical disciplines in the pre-IR module survey, this decreased to 17 % (27/157) in the post-IR module survey. The correct responses regarding knowledge of selected IR procedures improved from 70 to 94 % for venous access, 78 to 99 % for uterine fibroid embolization, 75 to 97 % for GI bleeding embolization, 60 to 92 % for trauma embolization, 71 to 92 % for tumor ablation, and 81 to 94 % for angioplasty and stenting in peripheral arterial disease. With regard to knowledge of IR clinical roles, responses improved from 42 to 59 % for outpatient clinic review of patients and having inpatient beds, 63–76 % for direct patient consultation, and 43–60 % for having regular ward rounds. The number of students who would consider a career in IR increased from 60 to 73 %.ConclusionDelivering an undergraduate IR curriculum increased the knowledge and understanding of various aspects of IR and also the general enthusiasm for pursuing this specialty as a future career choice.

The Introduction of an Undergraduate Interventional Radiology (IR) Curriculum: Impact on Medical Student Knowledge and Interest in IR

Energy Technology Data Exchange (ETDEWEB)

Shaikh, M. [Bradford Royal Infirmary, Department of Radiology, Bradford Teaching Hospital Foundation Trust (United Kingdom); Shaygi, B. [Royal Devon and Exeter Hospital, Interventional Radiology Department (United Kingdom); Asadi, H., E-mail: asadi.hamed@gmail.com; Thanaratnam, P.; Pennycooke, K.; Mirza, M.; Lee, M., E-mail: mlee@rcsi.ie [Beaumont Hospital, Interventional Radiology Service, Department of Radiology (Ireland)

2016-04-15

IntroductionInterventional radiology (IR) plays a vital role in modern medicine, with increasing demand for services, but with a shortage of experienced interventionalists. The aim of this study was to determine the impact of a recently introduced IR curriculum on perception, knowledge, and interest of medical students regarding various aspects of IR.MethodsIn 2014, an anonymous web-based questionnaire was sent to 309 4th year medical students in a single institution within an EU country, both before and after delivery of a 10-h IR teaching curriculum.ResultsSeventy-six percent (236/309) of the respondents participated in the pre-IR module survey, while 50 % (157/309) responded to the post-IR module survey. While 62 % (147/236) of the respondents reported poor or no knowledge of IR compared to other medical disciplines in the pre-IR module survey, this decreased to 17 % (27/157) in the post-IR module survey. The correct responses regarding knowledge of selected IR procedures improved from 70 to 94 % for venous access, 78 to 99 % for uterine fibroid embolization, 75 to 97 % for GI bleeding embolization, 60 to 92 % for trauma embolization, 71 to 92 % for tumor ablation, and 81 to 94 % for angioplasty and stenting in peripheral arterial disease. With regard to knowledge of IR clinical roles, responses improved from 42 to 59 % for outpatient clinic review of patients and having inpatient beds, 63–76 % for direct patient consultation, and 43–60 % for having regular ward rounds. The number of students who would consider a career in IR increased from 60 to 73 %.ConclusionDelivering an undergraduate IR curriculum increased the knowledge and understanding of various aspects of IR and also the general enthusiasm for pursuing this specialty as a future career choice.

Ion beam synthesis of IrSi3 by implantation of 2 MeV Ir ions

International Nuclear Information System (INIS)

Sjoreen, T.P.; Chisholm, M.F.; Hinneberg, H.J.

1992-11-01

Formation of a buried IrSi 3 layer in (111) oriented Si by ion implantation and annealing has been studied at an implantation energy of 2 MeV for substrate temperatures of 450--550C. Rutherford backscattering (RBS), ion channeling and cross-sectional transmission electron microscopy showed that a buried epitaxial IrSi 3 layer is produced at 550C by implanting ≥ 3.4 x 10 17 Ir/cm 2 and subsequently annealing for 1 h at 1000C plus 5 h at 1100C. At a dose of 3.4 x 10 17 Ir/cm 2 , the thickness of the layer varied between 120 and 190 nm and many large IrSi 3 precipitates were present above and below the film. Increasing the dose to 4.4 x 10 17 Ir/cm 2 improved the layer uniformity at the expense of increased lattice damage in the overlying Si. RBS analysis of layer formation as a function of substrate temperature revealed the competition between the mechanisms for optimizing surface crystallinity vs. IrSi 3 layer formation. Little apparent substrate temperature dependence was evident in the as-implanted state but after annealing the crystallinity of the top Si layer was observed to deteriorate with increasing substrate temperature while the precipitate coarsening and coalescence improved

Microstructural evolution and wear behaviors of laser cladding Ti_2Ni/α(Ti) dual-phase coating reinforced by TiB and TiC

International Nuclear Information System (INIS)

Song, R.; Li, J.; Shao, J.Z.; Bai, L.L.; Chen, J.L.; Qu, C.C.

2015-01-01

Graphical abstract: - Highlights: • A TiC+TiB reinforced intermetallic matrix coating was fabricated by laser cladding. • The microstructural evolution of the reinforcements was analyzed. • A formula was established in term of wear loss, sliding time and applied load. • Wear behaviors were investigated by in situ continuing tests in different time intervals. • The transformation of wear mechanism at different applied loads was revealed. - Abstract: The Ti_2Ni/α(Ti) dual-phase coating reinforced by TiB and TiC was fabricated on the Ti6Al4V substrate by laser cladding. Phase constituents were confirmed by a theoretical prediction combined with X-ray diffraction (XRD) analyses. From the surface to the bottom of the coating, a regular evolution of the reinforcements’ microstructure, namely TiC_p+(TiB+TiC)_e, (TiB+TiC)_e and TiB_p+(TiB+TiC)_e (p and e were the abbreviations of primary and eutectic, respectively), was investigated by scanning electron microscopy (SEM). The coating possessed the higher microhardness than that of the substrate. An in situ dynamic method (in situ continuing tests at different time intervals) was designed to reveal wear behaviors at different wear stages. A quantitative calculation formula was established by a mathematic model to predict wear losses under different sliding time and applied loads in a definite precision. The wear mechanism was transformed from brittle debonding (at 10 N) to the joint action of brittle debonding and micro-cutting (at 20 N and 30 N) due to the microstructural evolution across the depth from the surface of the coating.

Initial testing of TiB2 and TiC coated limiters in ISX-B

International Nuclear Information System (INIS)

Langley, R.A.; Emerson, R.A.; Whitley, J.B.; Mullendore, A.W.

1980-01-01

Low-Z coatings on graphite substrates have been developed for testing as limiters in the Impurity Study Experiment (ISX-B) tokamak. Laboratory and tokamak testings have been accomplished. The laboratory tests included thermal shock experiments by means of pulsed e-beam irradiation, arcing experiments, and hydrogen and xenon ion erosion experiments. The tokamak testing consisted of ohmically heated plasma exposures with energy depositions up to 10 kJ/discharge on the limiters. The coatings, applied by chemical vapor deposition, consisted of TiB 2 and TiC deposited on POCO graphite substrates. The limiter samples were interchanged through the use of a transfer chamber without atmospheric exposure of the ISX-B tokamak. Limiter samples were baked out in the transfer chamber before use in the tokamak. Provisions for both heating and cooling the limiter during tokamak discharge were made. Initial testing of the limiter samples consisted of exposure to only ohmically heated plasma; subsequent testing will be performed in neutral-beam-heated plasmas having up to 3 MW of injected power. Bulk and surface temperatures of the samples were measured to allow the determination of energy deposition. Extensive plasma and edge diagnostics were used to evaluate the effect of the limiter on the plasma (e.g. vacuum ultraviolet spectrometry to determine plasma impurity concentrations, Thomson scattering to determine Z effective, IR camera to measure limiter surface temperature, and laser fluorescence spectrometry to determine neutral impurity concentration and velocity distribution in the limiter region). (orig.)

Microstructure of in-situ Synthesized (TiB+TiC)/Ti Composites Prepared by Hot-pressing

Institute of Scientific and Technical Information of China (English)

Zhenzhu ZHENG; Lin GENG; Honglin WANG; Weimin ZHOU; Hongyu XU

2003-01-01

In-situ 5 vol.pct TiB whiskers and TiC particulates reinforced Ti composites were fabricated by blending Ti powderand B4C particulates followed by reactive hot-pressing. The microstructure of the composites was investigated byusing differential scanning c

Stress analysis and microstructure of PVD monolayer TiN and multilayer TiN/(Ti,Al)N coatings

NARCIS (Netherlands)

Carvalho, NJM; Zoestbergen, E; Kooi, BJ; De Hosson, JTM

2003-01-01

Two PVD titanium nitride based coatings; monolayer TiN and multilayer resulting from the stacking of TiN and (Ti,Al)N layers were evaluated with respect to their stress state and microstructure. The TiN was deposited by triode evaporation ion plating, whereas the TiN/(Ti,AI)N was deposited using a

TiO{sub 2} synthesized by the method of polymeric precursor (Pechini): structure of the intermediate resine; TiO{sub 2} sintetizado por el metodo de precursor polimerico (Pechini): estructura de la resina intermedia

Energy Technology Data Exchange (ETDEWEB)

Vargas, M. A.; Granco, Y.; Ochoa, Y.; Ortegon, Y.; Rodriguez Paez, J. E.

2011-07-01

In this work, the polymeric precursor method (Pechini method) was used to synthesize titanium dioxide. This process allowed a bigger control on the purity of the oxide and the crystalline phase present in the material. In this case, the principal phase was anatase. The resine obtained in this process was characterized using NMR and IR spectroscopy to determine their structure. With this information we proposed a resine structure model. To finish the process, the resin was thermally treated to obtain TiO{sub 2}. This oxide was characterized using different techniques: ray-X diffraction (RDX) and electron microscopy (TEM and SEM). The results indicated that the TiO{sub 2} anatase phase can be obtained at 450 degree centigrade with a particle size <100nm. (Author) 10 refs.

Self-Consolidation Mechanism of Nanostructured Ti5Si3 Compact Induced by Electrical Discharge

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W. H. Lee

2015-01-01

Full Text Available Electrical discharge using a capacitance of 450 μF at 7.0 and 8.0 kJ input energies was applied to mechanical alloyed Ti5Si3 powder without applying any external pressure. A solid bulk of nanostructured Ti5Si3 with no compositional deviation was obtained in times as short as 159 μsec by the discharge. During an electrical discharge, the heat generated is the required parameter possibly to melt the Ti5Si3 particles and the pinch force can pressurize the melted powder without allowing the formation of pores. Followed rapid cooling preserved the nanostructure of consolidated Ti5Si3 compact. Three stepped processes during an electrical discharge for the formation of nanostructured Ti5Si3 compact are proposed: (a a physical breakdown of the surface oxide of Ti5Si3 powder particles, (b melting and condensation of Ti5Si3 powder by the heat and pinch pressure, respectively, and (c rapid cooling for the preservation of nanostructure. Complete conversion yielding a single phase Ti5Si3 is primarily dominated by the solid-liquid mechanism.

Smulkaus ir vidutinio verslo konkurencingumas Lietuvoje

OpenAIRE

Vijeikis, Juozas; Makštutis, Antanas

2009-01-01

Straipsnio mokslinė problema, naujumas ir aktualumas. Konkurencingumas kaip įmonių efektyvios veiklos reiškinys yra aktualus šalies verslo gyvenime vykdant darnios ekonominės plėtros politiką. Ši politika kaip problema smulkaus ir vidutinio verslo (SVV) plėtrai ir konkurencingumui didinti nėra sistemiškai ištirta ir aprašyta Lietuvos sąlygomis mokslinėje ir praktinėje literatūroje. Vienas svarbiausių veiksnių, siekiant spartaus ekonominio augimo, yra darnios verslininkystės plėtra Lietuvoje n...

Structural, phase stability, electronic, elastic properties and hardness of IrN{sub 2} and zinc blende IrN: First-principles calculations

Energy Technology Data Exchange (ETDEWEB)

Zhou, Zhaobo [Key Laboratory of Advanced Materials of Yunnan Province & Key Laboratory of Advanced Materials of Non-Ferrous and Precious Rare Metals Ministry of Education, Kunming University of Science and Technology, Kunming 650093 (China); Zhou, Xiaolong, E-mail: kmzxlong@163.com [Key Laboratory of Advanced Materials of Yunnan Province & Key Laboratory of Advanced Materials of Non-Ferrous and Precious Rare Metals Ministry of Education, Kunming University of Science and Technology, Kunming 650093 (China); Zhang, Kunhua [State Key Laboratory of Rare Precious Metals Comprehensive Utilization of New Technologies, Kunming Institute of Precious Metals, Kunming 650106 (China)

2016-12-15

First-principle calculations were performed to investigate the structural, phase stability, electronic, elastic properties and hardness of monoclinic structure IrN{sub 2} (m-IrN{sub 2}), orthorhombic structure IrN{sub 2} (o-IrN{sub 2}) and zinc blende structure IrN (ZB IrN). The results show us that only m-IrN{sub 2} is both thermodynamic and dynamic stability. The calculated band structure and density of states (DOS) curves indicate that o-IrN{sub 2} and ZB Ir-N compounds we calculated have metallic behavior while m-IrN{sub 2} has a small band gap of ~0.3 eV, and exist a common hybridization between Ir-5d and N-2p states, which forming covalent bonding between Ir and N atoms. The difference charge density reveals the electron transfer from Ir atom to N atom for three Ir-N compounds, which forming strong directional covalent bonds. Notable, a strong N-N bond appeared in m-IrN{sub 2} and o-IrN{sub 2}. The ratio of bulk to shear modulus (B/G) indicate that three Ir-N compounds we calculated are ductile, and ZB IrN possesses a better ductility than two types IrN{sub 2}. m-IrN{sub 2} has highest Debye temperature (736 K), illustrating it possesses strongest covalent bonding. The hardness of three Ir-N compounds were also calculated, and the results reveal that m-IrN{sub 2} (18.23 GPa) and o-IrN{sub 2} (18.02 GPa) are ultraincompressible while ZB IrN has a negative value, which may be attributed to phase transition at ca. 1.98 GPa.

Investigation of the electrochemical behaviour of thermally prepared Pt-IrO2 electrodes

Directory of Open Access Journals (Sweden)

Konan Honoré Kondro

2008-04-01

Full Text Available Different IrO2 electrodes in which the molar percentage of platinum (Pt varies from 0 %mol Pt to 100 %mol Pt were prepared on titanium (Ti substrate by thermal decomposition techniques. The electrodes were characterized physically (SEM, XPS and electrochemically and then applied to methanol oxidation. The SEM micrographs indicated that the electrodes present different morphologies depending on the amount of platinum in the deposit and the cracks observed on the 0 %mol Pt electrode diminish in size tending to a compact and rough surface for 70 %mol Pt electrode. XPS results indicate good quality of the coating layer deposited on the titanium substrate. The voltammetric investigations in the supporting electrolyte indicate that the electrodes with low amount of platinum (less than 10 %mol Pt behave as pure IrO2. But in the case of electrodes containing more than 40 %mol Pt, the voltammograms are like that of platinum. Electrocatalytic activity towards methanol oxidation was observed with the electrodes containing high amount of platinum. Its oxidation begins at a potential of about 210 mV lower on such electrodes than the pure platinum electrode (100 %mol Pt. But for electrode containing low quantity of Pt, the surface of the coating is essentially composed of IrO2 and methanol oxidation occurs in the domain of water decomposition solely. The increase of the electrocatalytic behaviour of the electrodes containing high amount of Pt towards methanol oxidation is due to the bifunctional behaviour of the electrodes.

Evaluation of APC NbTi superconductor in a model dipole magnet

International Nuclear Information System (INIS)

Scanlan, R.M.; Lietzke, A.; Royet, J.; Wandesforde, A.; Taylor, C.E.; Wong, J.; Rudziak, M.K.

1993-01-01

The artificial pinning center (APC) approach to NbTi superconductor fabrication offers the potential benefits of higher current density and lower cost than the conventional process for NbTi. We have been evaluating several approaches for fabricating NbTi via the APC approach to determine whether these advantages can be realized in a practical conductor. The study began with the fabrication by several vendors of 10kg size samples which were evaluated as short samples. This was followed by the scale-up of one process to 150mm diameter billets. This material was evaluated first in a solenoid configuration and recently in a one-meter long dipole. We will report here on the results of these coil tests and other characterization results for this new material. We will also describe the plans to continue the scale-up to full size billets and we will discuss the potential cost savings of this approach compared with conventional NbTi fabrication

Industrial radiography with Ir-192 using computed radiographic technique

International Nuclear Information System (INIS)

Ngernvijit, Narippawaj; Punnachaiya, Suvit; Chankow, Nares; Sukbumperng, Ampai; Thong-Aram, Decho

2003-01-01

The aim of this research is to study the utilization of a low activity Ir-192 gamma source for industrial radiographic testing using the Computed Radiography (CR) system. Due to a photo-salbutamol Imaging Plate (I P) using in CR is much more radiation sensitive than a type II film with lead foil intensifying screen, the exposure time with CR can be significantly reduced. For short-lived gamma-ray source like Ir-192 source, the exposure time must be proportionally increased until it is not practical particularly for thick specimens. Generally, when the source decays to an activity of about 5 Ci or less, it will be returned to the manufacturer as a radioactive waste. In this research, the optimum conditions for radiography of a 20 mm thick welded steel sample with 2.4 Ci Ir-192 was investigated using the CR system with high resolution image plate, i.e. type Bas-SR of the Fuji Film Co. Ltd. The I P was sandwiched by a pair of 0.25 mm thick Pb intensifying sere en. Low energy scattered radiations was filtered by placing another Pb sheet with a thickness of 3 mm under the cassette. It was found that the CR image could give a contrast sensitivity of 2.5 % using only 3-minute exposure time which was comparable to the image taken by the type II film with Pb intensifying screen using the exposure time of 45 minutes

Highly Al-doped TiO{sub 2} nanoparticles produced by Ball Mill Method: structural and electronic characterization

Energy Technology Data Exchange (ETDEWEB)

Santos, Desireé M. de los, E-mail: desire.delossantos@uca.es; Navas, Javier, E-mail: javier.navas@uca.es; Sánchez-Coronilla, Antonio; Alcántara, Rodrigo; Fernández-Lorenzo, Concha; Martín-Calleja, Joaquín

2015-10-15

Highlights: • Highly Al-doped TiO{sub 2} nanoparticles were synthesized using a Ball Mill Method. • Al doping delayed anatase to rutile phase transformation. • Al doping allow controlling the structural and electronic properties of nanoparticles. - Abstract: This study presents an easy method for synthesizing highly doped TiO{sub 2} nanoparticles. The Ball Mill method was used to synthesize pure and Al-doped titanium dioxide, with an atomic percentage up to 15.7 at.% Al/(Al + Ti). The samples were annealed at 773 K, 973 K and 1173 K, and characterized using ICP-AES, XRD, Raman spectroscopy, FT-IR, TG, STEM, XPS, and UV–vis spectroscopy. The effect of doping and the calcination temperature on the structure and properties of the nanoparticles were studied. The results show high levels of internal doping due to the substitution of Ti{sup 4+} ions by Al{sup 3+} in the TiO{sub 2} lattice. Furthermore, anatase to rutile transformation occurs at higher temperatures when the percentage of doping increases. Therefore, Al doping allows us to control the structural and electronic properties of the nanoparticle synthesized. So, it is possible to obtain nanoparticles with anatase as predominant phase in a higher range of temperature.

Protection of p+-n-Si Photoanodes by Sputter-Deposited Ir/IrOxThin Films

DEFF Research Database (Denmark)

Mei, Bastian Timo; Seger, Brian; Pedersen, Thomas

2014-01-01

Sputter deposition of Ir/IrOx on p+-n-Si without interfacial corrosion protection layers yielded photoanodes capable of efficient water oxidation (OER) in acidic media (1 M H2SO4). Stability of at least 18 h was shown by chronoamperomety at 1.23 V versus RHE (reversible hydrogen electrode) under 38...... density of 1 mA/cm2 at 1.05 V vs. RHE. Further improvement by heat treatment resulted in a cathodic shift of 40 mV and enabled a current density of 10 mA/cm2 (requirements for a 10% efficient tandem device) at 1.12 V vs. RHS under irradiation. Thus, the simple IrOx/Ir/p+-n-Si structures not only provide...

Influence of Ti in the β-Zr(Fe) phase stability at ambient temperature

International Nuclear Information System (INIS)

Coelho, J.S.

1980-12-01

Investigations of the Fe-Ti-Zr alloy system with concentrations ranging from 1 at.% Ti to 20 at.% Ti and with a fixed concentration of 4 at.% Fe were performed using X-Ray diffraction, Mossbauer Spectroscopy and Optical and Electronic Metallographies. The alloys were melted in arc furnace in argon atmosphere and after being homogenized, they were quenched from the beta field into cold water in order to retain the high temperature β-Zr(Fe)-Ti phase. The obtained results show that the beta phase was partially retained until the concentration of 7 at.% Ti and was completely retained at the concentration equal to or higher than 8 at.% Ti. It is assumed in Moessbauer Spectroscopy a doublet for the beta phase and a singlet for the supersatured α'-Zr(Fe)-Ti phase resulting from the martensitic transformation. The relative amount of each phase detected by Moessbauer Spectroscopy was measured by the relative area of the each spectral line. The stability of the beta phase at room temperature was discussed in terms of short-range ordering caused by the Fe-Ti bonds. Some related properties were discussed through the changing of the lattice parameter, isomer shift and quadrupole splitting. (Author) [pt

Microstructure and Properties of (TiB2 + NiTi)/Ti Composite Coating Fabricated by Laser Cladding

Science.gov (United States)

Lin, Yinghua; Lei, Yongping; Fu, Hanguang; Lin, Jian

2015-10-01

Agglomerated TiB2 particle and network-like structure-reinforced titanium matrix composite coatings were prepared by laser cladding of the Ni + TiB2 + Ti preplaced powders on Ti-6Al-4V alloy. The network-like structure mainly consisted of NiTi and Ni3Ti. Through the experiment, it was found that the size of agglomerated particle gradually decreased with the increase of Ti content, but the number of the network-like structure first increased and then disappeared. In-situ reaction competition mechanism and the formation of network-like structure were discussed. The average micro-hardness gradually decreased with the increase of Ti content, but the average fracture toughness gradually increased. Meanwhile, the wear resistance of the coatings is higher than that of the substrate, but the wear loss of the coatings is gradually increased with the increase of Ti content.

Novel cross-talk between IGF-IR and DDR1 regulates IGF-IR trafficking, signaling and biological responses

Science.gov (United States)

Sacco, Antonella; Morcavallo, Alaide; Vella, Veronica; Voci, Concetta; Spatuzza, Michela; Xu, Shi-Qiong; Iozzo, Renato V.; Vigneri, Riccardo; Morrione, Andrea; Belfiore, Antonino

2015-01-01

The insulin-like growth factor-I receptor (IGF-IR), plays a key role in regulating mammalian development and growth, and is frequently deregulated in cancer contributing to tumor initiation and progression. Discoidin domain receptor 1 (DDR1), a collagen receptor tyrosine-kinase, is as well frequently overexpressed in cancer and implicated in cancer progression. Thus, we investigated whether a functional cross-talk between the IGF-IR and DDR1 exists and plays any role in cancer progression. Using human breast cancer cells we found that DDR1 constitutively associated with the IGF-IR. However, this interaction was enhanced by IGF-I stimulation, which promoted rapid DDR1 tyrosine-phosphorylation and co-internalization with the IGF-IR. Significantly, DDR1 was critical for IGF-IR endocytosis and trafficking into early endosomes, IGF-IR protein expression and IGF-I intracellular signaling and biological effects, including cell proliferation, migration and colony formation. These biological responses were inhibited by DDR1 silencing and enhanced by DDR1 overexpression. Experiments in mouse fibroblasts co-transfected with the human IGF-IR and DDR1 gave similar results and indicated that, in the absence of IGF-IR, collagen-dependent phosphorylation of DDR1 is impaired. These results demonstrate a critical role of DDR1 in the regulation of IGF-IR action, and identify DDR1 as a novel important target for breast cancers that overexpress IGF-IR. PMID:25840417

Antibacterial activity and cell compatibility of TiZrN, TiZrCN, and TiZr-amorphous carbon coatings

Energy Technology Data Exchange (ETDEWEB)

Huang, Heng-Li [School of Dentistry, China Medical University, Taichung 404, Taiwan (China); Department of Bioinformatics and Medical Engineering, Asia University, Taichung 41354, Taiwan (China); Chang, Yin-Yu, E-mail: yinyu@nfu.edu.tw [Department of Mechanical and Computer-aided Engineering, National Formosa University, Yunlin 632, Taiwan (China); Liu, Jia-Xu [Department of Mechanical and Computer-aided Engineering, National Formosa University, Yunlin 632, Taiwan (China); Tsai, Ming-Tzu [Department of Biomedical Engineering, Hungkuang University, Taichung 433, Taiwan (China); Lai, Chih-Ho [Department of Microbiology and Immunology, Graduate Institute of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan (China)

2015-12-01

A cathodic-arc evaporation system with plasma-enhanced duct equipment was used to deposit TiZrN, TiZrCN, and TiZr/a-C coatings. Reactive gases (N{sub 2} and C{sub 2}H{sub 2}) activated by the Ti and Zr plasma in the evaporation process was used to deposit the TiZrCN and TiZr/a-C coatings with different C and nitrogen contents. The crystalline structures and bonding states of coatings were analyzed by X-ray diffraction and X-ray photoelectron spectroscopy. The microbial activity of the coatings was evaluated against Staphylococcus aureus (Gram-positive bacteria) and Actinobacillus actinomycetemcomitans (Gram-negative bacteria) by in vitro antibacterial analysis using a fluorescence staining method employing SYTO9 and a bacterial-viability test on an agar plate. The cell compatibility and morphology related to CCD-966SK cell-line human skin fibroblast cells on the coated samples were also determined using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay, reverse-transcriptase-polymerase chain reaction, and scanning electron microscopy. The results suggest that the TiZrCN coatings not only possess better antibacterial performance than TiZrN and TiZr/a-C coatings but also maintain good compatibility with human skin fibroblast cells. - Highlights: • TiZrN, TiZrCN, and TiZr/a-C coatings were deposited using cathodic arc evaporation. • The TiZrCN showed a composite structure containing TiN, ZrN, and a-C. • The TiZrCN-coated Ti showed the least hydrophobicity among the samples. • The TiZrCN-coated Ti showed good human skin fibroblast cell viability. • The TiZrCN-coated Ti exhibited good antibacterial performance.

Synthesis and characterization of a binary oxide ZrO2–TiO2 and its ...

Indian Academy of Sciences (India)

Administrator

Synthesis and characterization of a binary oxide ZrO2–TiO2 and its application in ... Solar cells based on dye-sensitized TiO2 nanoparticles were first developed by Grätzel ... cells, resulting in high Jsc (short-circuit current density),. *Author for .... simple method to study dye sensitization of semiconduc- tors. It is found that the ...

TiO2/Cu2O composite based on TiO2 NTPC photoanode for photoelectrochemical (PEC) water splitting under visible light

KAUST Repository

Shi, Le

2015-05-01

Water splitting through photoelectrochemical reaction is widely regarded as a major method to generate H2 , a promising source of renewable energy to deal with the energy crisis faced up to human being. Efficient exploitation of visible light in practice of water splitting with pure TiO2 material, one of the most popular semiconductor material used for photoelectrochemical water splitting, is still challenging. One dimensional TiO2 nanotubes is highly desired with its less recombination with the short distance for charge carrier diffusion and light-scattering properties. This work is based on TiO2 NTPC electrode by the optimized two-step anodization method from our group. A highly crystalized p-type Cu2O layer was deposited by optimized pulse potentiostatic electrochemical deposition onto TiO2 nanotubes to enhance the visible light absorption of a pure p-type TiO2 substrate and to build a p-n junction at the interface to improve the PEC performance. However, because of the real photocurrent of Cu2O is far away from its theoretical limit and also poor stability in the aqueous environment, a design of rGO medium layer was added between TiO2 nanotube and Cu2O layer to enhance the photogenerated electrons and holes separation, extend charge carrier diffusion length (in comparison with those of conventional pure TiO2 or Cu2O materials) which could significantly increase photocurrent to 0.65 mA/cm2 under visible light illumination (>420 nm) and also largely improve the stability of Cu2O layer, finally lead to an enhancement of water splitting performance.

Application of ion implantation RBS to the study of electrocatalysis

International Nuclear Information System (INIS)

Kelly, E.J.; Vallet, C.E.; White, C.W.

1990-01-01

Ir-implanted titanium near-surface alloys were prepared by ion implantation, characterized (Ir concentration/depth profiles) by Rutherford backscattering (RBS), and subsequently anodically oxidized to form electrocatalytically active Ir x Ti 1-x O 2 /Ti electrodes. The electrochemical behavior of the metallic-like Ir 4 Ti 1-x O 2 /Ti electrodes in acidic chloride, sulfate, and perchlorate solutions was investigated, and the results compared with those previously obtained with similarly prepared Ru x Ti 1-x O 2 /Ti electrodes. For both electrodes, M x Ti 1-x O 2 /Ti (M equals Ir or Ru), the Tafel slope for the Cl 2 evolution reaction is 40 mV, i.e.,δE/δlog i equals 2.303 (2RT/3F). The reaction order (n) with respect to chloride ion concentration δlogi/δlog[Cl - ] + 1, where K 9 equals 54.9 dm 3 mol -1 for Ir x Ti 1-x O 2 /Ti and K 9 equals 40 dm 3 mol -1 for Ru x Ti 1-x O 2 /Ti. A modified Volmer-Heyrovsky mechanism, one in which the role of absorbed chloride ions is taken into account, is shown to be consistent with aforementioned diagnostic parameters

Superluminal travel, UV/IR mixing, and turbulence in a (1+1)-dimensional world

International Nuclear Information System (INIS)

Dubovsky, Sergei; Gorbenko, Victor

2011-01-01

We study renormalizable Lorentz invariant stable quantum field theories in two space-time dimensions with instantaneous causal structure (causal ordering induced by the light 'cone' time ordering). These models provide a candidate UV completion of the two-dimensional ghost condensate. They exhibit a peculiar UV/IR mixing - energies of all excitations become arbitrarily small at high spatial momenta. We discuss several phenomena associated with this mixing. These include the impossibility to reach a thermal equilibrium and metastability of all excitations towards decay into short-wavelength modes resulting in an indefinite turbulent cascade. In spite of the UV/IR mixing in many cases the UV physics can still be decoupled from low-energy phenomena. However, a patient observer in the Lineland is able to produce arbitrarily heavy particles simply by waiting for a long enough time.

Highly uniform bipolar resistive switching characteristics in TiO2/BaTiO3/TiO2 multilayer

International Nuclear Information System (INIS)

Ma, W. J.; Zhang, X. Y.; Wang, Ying; Zheng, Yue; Lin, S. P.; Luo, J. M.; Wang, B.; Li, Z. X.

2013-01-01

Nanoscale multilayer structure TiO 2 /BaTiO 3 /TiO 2 has been fabricated on Pt/Ti/SiO 2 /Si substrate by chemical solution deposition method. Highly uniform bipolar resistive switching (BRS) characteristics have been observed in Pt/TiO 2 /BaTiO 3 /TiO 2 /Pt cells. Analysis of the current-voltage relationship demonstrates that the space-charge-limited current conduction controlled by the localized oxygen vacancies should be important to the resistive switching behavior. X-ray photoelectron spectroscopy results indicated that oxygen vacancies in TiO 2 play a crucial role in the resistive switching phenomenon and the introduced TiO 2 /BaTiO 3 interfaces result in the high uniformity of bipolar resistive switching characteristics

Study of excited states in 48Ti, 49Ti and 50Ti by means of radiative neutron capture

International Nuclear Information System (INIS)

Ruyl, J.F.A.G.

1983-12-01

The γ radiation produced by thermal neutron capture in a natural Ti target and in enriched 47 Ti and 49 Ti targets has been investigated. In the analysis 57 excited states of 48 Ti, 28 of 49 Ti and 31 of 50 Ti have been identified. The values for the 48 Ti and 49 Ti neutron binding energy agree with previous data, the value for 50 Ti differs by five standard deviations. The nature of the neutron capture mechanism has been investigated by comparing the present results with those from previous (d,p) work. It appears that in 47 Ti capture proceeds through a doorway state and that the potential capture mechanism is valid for 48 Ti and 49 Ti. The Fermi gas model gives a good representation of the nuclear level density in all three nuclei. From a measurement of the γ-ray circular polarization resulting from the capture of polarized neutrons, combined with previous (d,p) work, the spins of five 49 Ti levels could be determined, and those of 13 other 49 Ti levels could be confirmed. The combination of nuclear orientation measurements and circular polarization measurements had yielded the unambiguous determination of the spins of one 48 Ti state and of five 50 Ti states. Further spin and parity determinations for six 48 Ti and for five 50 Ti states have been obtained from the analysis of the identified branches together with the results of previous experiments. Shell-model calculations, which yielded excitation energies, branching ratios, lifetimes and (d,p) spectroscopic factors, give a good representation of the experimental data for the low-lying states in both even-even nuclei. (Auth.)

Surface modification of TiO2 with g-C3N4 for enhanced UV and visible photocatalytic activity

International Nuclear Information System (INIS)

Lei, Juying; Chen, Ying; Shen, Fan; Wang, Lingzhi; Liu, Yongdi; Zhang, Jinlong

2015-01-01

Highlights: • g-C 3 N 4 /TiO 2 was prepared by a one-step preparation under mild conditions. • Photocatalysts showed excellent activity under both UV and visible light. • A neat surface modification process is proved, excluding influence of N doping. • Two photocatalytic mechanisms under different wavelengths are proposed. • A wide range of available wavelengths would greatly improve practicability of TiO 2 . - Abstract: g-C 3 N 4 modified TiO 2 composites were prepared through a simple calcination process of anatase and cyanamide. The as-prepared samples were characterized by X-ray diffraction (XRD), diffuse reflectance spectrophotometry (DRS), fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), thermogravimetry differential thermal analysis (TG–DTA) and X-ray photoelectron spectroscopy (XPS), proving a successful modification of TiO 2 with g-C 3 N 4 . Photodegradation of acid orange 7 (AO7) was used to evaluate the photocatalytic activities of the composites, showing excellent activity of them under both visible and UV light. In addition, base treatment was then introduced to investigate the interaction between g-C 3 N 4 and TiO 2 . After removing the g-C 3 N 4 modified on TiO 2 by base, no nitrogen doping is found in TiO 2 lattice, demonstrating the g-C 3 N 4 was surface attached on TiO 2 and attributing all improvement of photocatalytic activity of g-C 3 N 4 /TiO 2 composite to the synergy between the two semiconductors

Facile one step synthesis of novel TiO2 nanocoral by sol-gel method using Aloe vera plant extract

Science.gov (United States)

Venkatesh, K. S.; Krishnamoorthi, S. R.; Palani, N. S.; Thirumal, V.; Jose, Sujin P.; Wang, Fu-Ming; Ilangovan, R.

2015-05-01

Titanium oxide (TiO2) nanoparticles (NPs) were synthesized by sol gel method using Aloe vera plant extract as a biological capping agent and a cauliflower-nanocoral morphology was observed in this technique. The assynthesized TiO2 nanopowder was calcined at a range of temperatures (300-600 °C) for 1 h. The influence of A. vera plant extract on the thermal, structural and morphological properties of TiO2 nanopowder was evaluated. Thermogravimetric analysis/differential thermal analysis was employed to study the thermal properties of the assynthesized TiO2 nanopowder. The crystallinity, phase transformation and the crystallite size of the calcined samples were studied by X-ray diffraction technique. XRD result confirmed the presence of TiO2 with anatase phase. FT Raman spectra showed the Raman active modes pertaining to the TiO2 anatase phase and Raman band shift was also observed with respect to particle size variation. The different functional group vibrations of as dried pure A. vera plant extract were compared with the mixture of TiO2 and A. vera plant extract by FT-IR analysis. The scanning electron microscopy images apparently showed the formation of spherical shaped NPs and also it demonstrated the effect of A. vera plant extract on the reduction of particles size. The surface area of the TiO2 NPs was measured through Brunauer-Emmett-Teller analysis. Transmission electron microscopy images ascertained that the spherical shaped TiO2 NPs were formed with cauliflower-nanocoral morphology decorated with nanopolyps with the size range between 15 and 30 nm.

HOMA1-IR and HOMA2-IR indexes in identifying insulin resistance and metabolic syndrome: Brazilian Metabolic Syndrome Study (BRAMS).

Science.gov (United States)

Geloneze, Bruno; Vasques, Ana Carolina Junqueira; Stabe, Christiane França Camargo; Pareja, José Carlos; Rosado, Lina Enriqueta Frandsen Paez de Lima; Queiroz, Elaine Cristina de; Tambascia, Marcos Antonio

2009-03-01

To investigate cut-off values for HOMA1-IR and HOMA2-IR to identify insulin resistance (IR) and metabolic syndrome (MS), and to assess the association of the indexes with components of the MS. Nondiabetic subjects from the Brazilian Metabolic Syndrome Study were studied (n = 1,203, 18 to 78 years). The cut-off values for IR were determined from the 90th percentile in the healthy group (n = 297) and, for MS, a ROC curve was generated for the total sample. In the healthy group, HOMA-IR indexes were associated with central obesity, triglycerides and total cholesterol (p 2.7 and HOMA2-IR > 1.8; and, for MS were: HOMA1-IR > 2.3 (sensitivity: 76.8%; specificity: 66.7%) and HOMA2-IR > 1.4 (sensitivity: 79.2%; specificity: 61.2%). The cut-off values identified for HOMA1-IR and HOMA2-IR indexes have a clinical and epidemiological application for identifying IR and MS in Westernized admixtured multi-ethnic populations.