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Sample records for monoclinic structure finally

  1. Structural, microstructural and vibrational analyses of the monoclinic tungstate BiLuWO{sub 6}

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    Ait Ahsaine, H. [Laboratoire Matériaux et Environnement LME, Faculté des Sciences, Université Ibn Zohr, BP 8106 Cité Dakhla, Agadir (Morocco); Taoufyq, A. [Laboratoire Matériaux et Environnement LME, Faculté des Sciences, Université Ibn Zohr, BP 8106 Cité Dakhla, Agadir (Morocco); Institut Matériaux Microélectronique et Nanosciences de Provence, IM2NP, UMR CNRS 7334, Université de Toulon, BP 20132, 83957 La Garde Cedex (France); Patout, L. [Institut Matériaux Microélectronique et Nanosciences de Provence, IM2NP, UMR CNRS 7334, Université de Toulon, BP 20132, 83957 La Garde Cedex (France); Ezahri, M.; Benlhachemi, A.; Bakiz, B. [Laboratoire Matériaux et Environnement LME, Faculté des Sciences, Université Ibn Zohr, BP 8106 Cité Dakhla, Agadir (Morocco); Villain, S.; Guinneton, F. [Institut Matériaux Microélectronique et Nanosciences de Provence, IM2NP, UMR CNRS 7334, Université de Toulon, BP 20132, 83957 La Garde Cedex (France); Gavarri, J.-R., E-mail: gavarri.jr@univ-tln.fr [Institut Matériaux Microélectronique et Nanosciences de Provence, IM2NP, UMR CNRS 7334, Université de Toulon, BP 20132, 83957 La Garde Cedex (France)

    2014-10-15

    The bismuth lutetium tungstate phase BiLuWO{sub 6} has been prepared using a solid state route with stoichiometric mixtures of oxide precursors. The obtained polycrystalline phase has been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. In the first step, the crystal structure has been refined using Rietveld method: the crystal cell was resolved using monoclinic system (parameters a, b, c, β) with space group A2/m. SEM images showed the presence of large crystallites with a constant local nominal composition (BiLuW). TEM analyses showed that the actual local structure could be better represented by a superlattice (a, 2b, c, β) associated with space groups P2 or P2/m. The Raman spectroscopy showed the presence of vibrational bands similar to those observed in the compounds BiREWO{sub 6} with RE=Y, Gd, Nd. However, these vibrational bands were characterized by large full width at half maximum, probably resulting from the long range Bi/Lu disorder and local WO{sub 6} octahedron distortions in the structure. - Graphical abstract: The average structure of BiLuWO{sub 6} determined from X-ray diffraction data can be represented by A2/m space group. Experimental Electron Diffraction patterns along the [0vw] zone axes of the monoclinic structure and associated simulated patterns show the existence of a monoclinic superstructure with space group P2 or P2/m. - Highlights: • A new monoclinic BiLuWO{sub 6} phase has been elaborated from solid-state reaction. • The space group of the monoclinic disordered average structure should be A2/m. • Transmission electron microscopy leads to a superlattice with P2/m space group. • Raman spectroscopy suggests existence of local disorder.

  2. Electronic structure and optical properties of monoclinic clinobisvanite BiVO4.

    Science.gov (United States)

    Zhao, Zongyan; Li, Zhaosheng; Zou, Zhigang

    2011-03-14

    Monoclinic clinobisvanite bismuth vanadate is an important material with wide applications. However, its electronic structure and optical properties are still not thoroughly understood. Density functional theory calculations were adopted in the present work, to comprehend the band structure, density of states, and projected wave function of BiVO(4). In particular, we put more emphasis upon the intrinsic relationship between its structure and properties. Based on the calculated results, its molecular-orbital bonding structure was proposed. And a significant phenomenon of optical anisotropy was observed in the visible-light region. Furthermore, it was found that its slightly distorted crystal structure enhances the lone-pair impact of Bi 6s states, leading to the special optical properties and excellent photocatalytic activities.

  3. Elastic stability and electronic structure of low energy tetragonal and monoclinic PdN2 and PtN2

    Institute of Scientific and Technical Information of China (English)

    Zhao Wen-Jie; Wang Yuan-Xu

    2009-01-01

    This paper studies the elastic and electronic structure properties of two new low-energy structures of PdN2 and PtN2 by first-principles calculations. It finds that tetragonal and monoclinic structures are more stable than a pyrite one. The always positive eigenvalues of the elastic constant matrix confirm that both the tetragonal and monoclinic structures are elastically stable. The origin of the low bulk modulus of the two structures is discussed. The results of the calculated density of states show that both of the two low-energy structures are metallic.

  4. Monoclinic tridymite in clast-rich impact melt rock from the Chesapeake Bay impact structure

    Science.gov (United States)

    Jackson, J.C.; Horton, J.W.; Chou, I.-Ming; Belkin, H.E.

    2011-01-01

    X-ray diffraction and Raman spectroscopy confirm a rare terrestrial occurrence of monoclinic tridymite in clast-rich impact melt rock from the Eyreville B drill core in the Chesapeake Bay impact structure. The monoclinic tridymite occurs with quartz paramorphs after tridymite and K-feldspar in a microcrystalline groundmass of devitrified glass and Fe-rich smectite. Electron-microprobe analyses revealed that the tridymite and quartz paramorphs after tridymite contain different amounts of chemical impurities. Inspection by SEM showed that the tridymite crystal surfaces are smooth, whereas the quartz paramorphs contain irregular tabular voids. These voids may represent microporosity formed by volume decrease in the presence of fluid during transformation from tridymite to quartz, or skeletal growth in the original tridymite. Cristobalite locally rims spherulites within the same drill core interval. The occurrences of tridymite and cristobalite appear to be restricted to the thickest clast-rich impact melt body in the core at 1402.02-1407.49 m depth. Their formation and preservation in an alkali-rich, high-silica melt rock suggest initially high temperatures followed by rapid cooling.

  5. Variable defect structures cause the magnetic low-temperature transition in natural monoclinic pyrrhotite

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    Koulialias, D.; Kind, J.; Charilaou, M.; Weidler, P. G.; Löffler, J. F.; Gehring, A. U.

    2016-02-01

    Non-stoichiometric monoclinic 4C pyrrhotite (Fe7S8) is a major magnetic remanence carrier in the Earth's crust and in extraterrestrial materials. Because of its low-temperature magnetic transition around 30 K also known as Besnus transition, which is considered to be an intrinsic property, this mineral phase is easily detectable in natural samples. Although the physical properties of pyrrhotite have intensively been studied, the mechanism behind the pronounced change in magnetization at the low-temperature transition is still debated. Here we report magnetization experiments on a pyrrhotite crystal (Fe6.6S8) that consists of a 4C and an incommensurate 5C* superstructure that are different in their defect structure. The occurrence of two superstructures is magnetically confirmed by symmetric inflection points in hysteresis measurements above the transition at about 30 K. The disappearance of the inflection points and the associated change of the hysteresis parameters indicate that the two superstructures become strongly coupled to form a unitary magnetic anisotropy system at the transition. From this it follows that the Besnus transition in monoclinic pyrrhotite is an extrinsic magnetic phenomenon with respect to the 4C superstructure and therefore the physics behind it is in fact different from that of the well-known Verwey transition.

  6. Crystal structure of a new monoclinic polymorph of N-(4-methylphenyl-3-nitropyridin-2-amine

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    Aina Mardia Akhmad Aznan

    2014-08-01

    Full Text Available The title compound, C12H11N3O2, is a second monoclinic polymorph (P21, with Z′ = 4 of the previously reported monoclinic (P21/c, with Z′ = 2 form [Akhmad Aznan et al. (2010. Acta Cryst. E66, o2400]. Four independent molecules comprise the asymmetric unit, which have the common features of a syn disposition of the pyridine N atom and the toluene ring, and an intramolecular amine–nitro N—H...O hydrogen bond. The differences between molecules relate to the dihedral angles between the rings which range from 2.92 (19 to 26.24 (19°. The geometry-optimized structure [B3LYP level of theory and 6–311 g+(d,p basis set] has the same features except that the entire molecule is planar. In the crystal, the three-dimensional architecture is consolidated by a combination of C—H...O, C—H...π, nitro-N—O...π and π–π interactions [inter-centroid distances = 3.649 (2–3.916 (2 Å].

  7. Discovery of Fe7O9: a new iron oxide with a complex monoclinic structure

    Science.gov (United States)

    Sinmyo, Ryosuke; Bykova, Elena; Ovsyannikov, Sergey V.; McCammon, Catherine; Kupenko, Ilya; Ismailova, Leyla; Dubrovinsky, Leonid

    2016-09-01

    Iron oxides are fundamentally important compounds for basic and applied sciences as well as in numerous industrial applications. In this work we report the synthesis and investigation of a new binary iron oxide with the hitherto unknown stoichiometry of Fe7O9. This new oxide was synthesized at high-pressure high-temperature (HP-HT) conditions, and its black single crystals were successfully recovered at ambient conditions. By means of single crystal X-ray diffraction we determined that Fe7O9 adopts a monoclinic C2/m lattice with the most distorted crystal structure among the binary iron oxides known to date. The synthesis of Fe7O9 opens a new portal to exotic iron-rich (M,Fe)7O9 oxides with unusual stoichiometry and distorted crystal structures. Moreover, the crystal structure and phase relations of such new iron oxide groups may provide new insight into the cycling of volatiles in the Earth’s interior.

  8. Monoclinic structured BiVO4 nanosheets: hydrothermal preparation, formation mechanism, and coloristic and photocatalytic properties.

    Science.gov (United States)

    Zhang, Li; Chen, Dairong; Jiao, Xiuling

    2006-02-16

    Bismuth vanadate (BiVO(4)) nanosheets have been hydrothermally synthesized in the presence of sodium dodecyl benzene sulfonate (SDBS) as a morphology-directing template. The nanosheets were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) equipped with an X-ray energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), IR spectroscopy, transmission electron microscopy (TEM), and high-resolution TEM (HR-TEM). The BiVO(4) nanosheets had a monoclinic structure, were ca. 10-40 nm thick, and showed a preferred (010) surface orientation. The formation mechanism and the effects of reaction temperature and time on the products were investigated. UV-visible diffuse reflection spectra indicated that the BiVO(4) nanosheets had outstanding spectral selectivity and improved color properties compared with the corresponding bulk materials. Furthermore, the nanosheets showed good visible photocatalytic activities as determined by degradation of N,N,N',N'-tetraethylated rhodamine (RB) under solar irradiation.

  9. Evolution of Structural, Electronic and Optical Properties of Monoclinic ZrO2 under High Pressure: A First Principles Study

    Institute of Scientific and Technical Information of China (English)

    HOU Ming-Xiu; HE Kai-Hua; ZHENG Guang; HOU Shu-En

    2008-01-01

    The structural, electronic and optical properties of the monoclinic ZrO2 were studied by ab initio calculations based on the density functional theory and pseudopotential method. The calculated lattice parameters and band gap are in agreement with the experimental and other theo- retical values. The evolution of lattice parameters and electronic properties were illustrated under high pressure. Meanwhile, the optical properties, such as adsorption coefficients, imaginary part of dielectric function, and energy loss function, were investigated under both ambient and high pressures.

  10. Structural, mechanical, and electronic properties of monoclinic N{sub 2}H{sub 5}N{sub 3} under pressure

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    Qi-Jun, Liu; Fu-Sheng, Liu, E-mail: qijunliu@home.swjtu.edu.cn [School of Physical Science and Technology, Southwest Jiaotong University, Key Laboratory of Advanced Technologies of Materials, Ministry of Education of China, Chengdu (China); Bond and Band Engineering Group, Sichuan Provincial Key Laboratory (for Universities) of High Pressure Science and Technology, Southwest Jiaotong University, Chengdu (China); Zheng-Tang, Liu [State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi' an, (China)

    2015-08-15

    Structural, elastic, mechanical, and electronic properties of monoclinic N{sub 2}H{sub 5}N{sub 3} at zero and high pressure have been investigated using the plane-wave ultrasoft pseudopotential method within the density-functional theory (DFT). The pressure dependences of structural parameters, elastic constants, mechanical properties, band gaps, and density of states of monoclinic N{sub 2}H{sub 5}N{sub 3} have been calculated and discussed. The obtained results show that monoclinic N{sub 2}H{sub 5}N{sub 3} is unstable at pressures exceeding the value 126.1 GPa. The ratio of B/G and the Cauchy’s pressure indicate that monoclinic N{sub 2}H{sub 5}N{sub 3} behaves in ductile nature with pressure ranging from 0 to 200 GPa. (author)

  11. Ultrasound assisted synthesis of monoclinic structured spindle BiVO4 particles with hollow structure and its photocatalytic property.

    Science.gov (United States)

    Liu, Wei; Cao, Lixin; Su, Ge; Liu, Haisong; Wang, Xiangfei; Zhang, Lan

    2010-04-01

    Bismuth vanadate (BiVO(4)) spindle particles with monoclinic scheelite structure have been successfully synthesized via a facile sonochemical method. The as-prepared BiVO(4) photocatalyst exhibited a hollow interior structure constructed from the self-assembly of cone shape primary nanocrystals. A possible oriented attachment growth mechanism has been proposed based on the results of time-dependent experiments, which indicates the formation of spindle particles is mainly attributed to the phase transformation procedure induced by ultrasound irradiation. A series of morphology evolutions of BiVO(4) from compact microspheres, to hollow microspheres, and then to spindle particles have been arrested in the process of sonochemical treatment. Optical absorption experiments revealed the BiVO(4) spindle had strong absorption in the visible light region. A much higher photocatalytic activity of these spindle particles was found in comparison with the SSR-BiVO(4) material for degradation of rhodamine-B under visible light irradiation, which may be ascribed to its special single-crystalline nanostructure.

  12. Triclinic-monoclinic-orthorhombic (T-M-O) structural transitions in phase diagram of FeVO4-CrVO4 solid solutions

    Science.gov (United States)

    Bera, Ganesh; Reddy, V. R.; Rambabu, P.; Mal, P.; Das, Pradip; Mohapatra, N.; Padmaja, G.; Turpu, G. R.

    2017-09-01

    Phase diagram of FeVO4-CrVO4 solid solutions pertinent with structural and magnetic phases is presented with unambiguous experimental evidences. Solid solutions Fe1-xCrxVO4 (0 ≤ x ≤ 1.0) were synthesized through the standard solid state route and studied by X-ray diffraction, scanning electron microscopy, energy dispersive spectra of X-rays, Raman spectroscopy, d.c. magnetization, and 57Fe Mössbauer spectroscopic studies. FeVO4 and CrVO4 were found to be in triclinic (P-1 space group) and orthorhombic structures (Cmcm space group), respectively. Cr incorporation into the FeVO4 lattice leads to the emergence of a new monoclinic phase dissimilar to the both end members of the solid solutions. In Fe1-xCrxVO4 up to x = 0.10, no discernible changes in the triclinic structure were found. A new structural monoclinic phase (C2/m space group) emerges within the triclinic phase at x = 0.125, and with the increase in Cr content, it gets stabilized with clear single phase signatures in the range of x = 0.175-0.25 as evidenced by the Rietveld analysis of the structures. Beyond x = 0.33, orthorhombic phase similar to CrVO4 (Cmcm space group) emerges and coexists with a monoclinic structure up to x = 0.85, which finally tends to stabilize in the range of x = 0.90-1.00. The Raman spectroscopic studies also confirm the structural transition. FeVO4 Raman spectra show the modes related to three nonequivalent V ions in the triclinic structure, where up to 42 Raman modes are observed in the present study. With the stabilization of structures having higher symmetry, the number of Raman modes decreases and the modes related to symmetry inequivalent sites collate into singular modes from the doublet structure. A systematic crossover from two magnetic transitions in FeVO4, at 21.5 K and 15.4 K to single magnetic transition in CrVO4, at 71 K (antiferromagnetic transition), is observed in magnetization studies. The intermediate solid solution with x = 0.15 shows two magnetic transitions

  13. Pure monoclinic La(1-x)Eu(x)PO₄ micro-/nano-structures: fast synthesis, shape evolution and optical properties.

    Science.gov (United States)

    Chen, Huanhuan; Ni, Yonghong; Ma, Xiang; Hong, Jianming

    2014-08-15

    Rare-earth-doped LaPO4 crystals have been attracting considerable interest. In this work, we reported the fast syntheses of LaPO4 and Eu-doped LaPO4 crystals via a simple oil-bath route, employing La(NO3)3 and KH2PO4 as the original reactants, Eu2O3 as the dopant. The reaction was carried out in ethylene glycol system at 120°C for 30 min without any assistance of surfactants or templates. X-ray powder diffraction analyses showed that pure monoclinic LaPO4 form was obtained in the system without Eu(3+) ions, and the above phase was not changed after integrating Eu(3+) ions into LaPO4 matrix. However, electron microscopy observations discovered that the integration of Eu(3+) ions into LaPO4 matrix obviously changed the morphology and size of the final La(1-x)Eu(x)PO4 crystals. With the increase in Eu(3+) amount from 0 to 0.35, the shape of the final product varied from homogeneous egg-like nanospheroids, to irregular grains with microscales, and to homogeneous microspheroids. Also, the Eu(3+) ion content in La(1-x)Eu(x)PO4 markedly affected the photoluminescence properties of the final product. When x=0.2, the product exhibited the strongest PL emission.

  14. Electronic structure of ferromagnetic semiconductor material on the monoclinic and rhombohedral ordered double perovskites La{sub 2}FeCoO{sub 6}

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    Fuh, Huei-Ru; Chang, Ching-Ray [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Graduate Institute of Applied Physics, National Taiwan University, Taipei 106, Taiwan (China); Weng, Ke-Chuan [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Wang, Yin-Kuo, E-mail: kant@ntnu.edu.tw [Center for General Education and Department of Physics, National Taiwan Normal University, Taipei 106, Taiwan (China)

    2015-05-07

    Double perovskite La{sub 2}FeCoO{sub 6} with monoclinic structure and rhombohedra structure show as ferromagnetic semiconductor based on density functional theory calculation. The ferromagnetic semiconductor state can be well explained by the superexchange interaction. Moreover, the ferromagnetic semiconductor state remains under the generalized gradient approximation (GGA) and GGA plus onsite Coulomb interaction calculation.

  15. Template-Free Synthesis of Monoclinic BiVO4 with Porous Structure and Its High Photocatalytic Activity

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    Pengyu Dong

    2016-08-01

    Full Text Available Monoclinic BiVO4 photocatalysts with porous structures were synthesized by a two-step approach without assistance of any templates. The as-prepared samples were characterized by X-ray diffraction pattern (XRD, scanning electron microscopy (SEM, Brunauer–Emmett–Teller (BET, ultraviolet–visible (UV–vis diffuse reflectance spectroscopy (DRS, photocurrent responses, and electrochemical impedance spectra (EIS. It is found that the as-prepared BiVO4 samples had a porous structure with aperture diameter of 50–300 nm. Moreover, the BET specific surface area of the porous BiVO4-200 °C sample reaches up to 5.69 m2/g, which is much higher than that of the sample of BiVO4 particles without porous structure. Furthermore, a possible formation mechanism of BiVO4 with porous structure was proposed. With methylene blue (MB as a model compound, the photocatalytic oxidation of organic contaminants in aqueous solution was investigated under visible light irradiation. It is found that the porous BiVO4-200 °C sample exhibits the best photocatalytic activity, and the photocatalytic rate constant is about three times of that of the sample of BiVO4 particles without porous structure. In addition, the photocurrent responses and electrochemical impedance spectra strongly support this conclusion.

  16. Synthesis of monoclinic structured BiVO4 spindly microtubes in deep eutectic solvent and their application for dye degradation.

    Science.gov (United States)

    Liu, Wei; Yu, Yaqin; Cao, Lixin; Su, Ge; Liu, Xiaoyun; Zhang, Lan; Wang, Yonggang

    2010-09-15

    Monoclinic structured spindly bismuth vanadate microtubes were fabricated on a large scale by a simple ionothermal treatment in the environment-friendly green solvent of urea/choline chloride. The as-prepared samples were characterized by XRD, SEM, TEM, IR and their photocatalytic activity was evaluated by photocatalytic decolorization of rhodamine B aqueous solution under visible-light irradiation. As-obtained BiVO(4) microtubes exhibit the spindly shape with a side length of ca. 800 nm and a wall thickness of ca. 100 nm. The opening of these microtubes presents a saw-toothed structure, which is seldom in other tube-shaped materials. The formation mechanism of the spindly microtubes is ascribed to the complex cooperation of the reaction-crystallization process controlled by BiOCl and the nucleation-growth process of nanosheets induced by solvent molecules attached on the surface of microtubes. Such spindly microtubes exhibit much higher visible-light photocatalytic activity than that of bulk BiVO(4) prepared by solid-state reaction, possibly resulting from their large surface area and improved crystallinity.

  17. Electronic structure and magnetic properties of monoclinic β-Cu2V2O7 : A GGA+U study

    Science.gov (United States)

    Yashima, Masatomo; Suzuki, Ryosuke O.

    2009-03-01

    A first-principles study on monoclinic C2/c copper pyrovanadate β-Cu2V2O7 has been performed using the generalized gradient approximation (GGA) and GGA+U method. The optimized unit-cell parameters and atomic coordinates of β-Cu2V2O7 agree well with experimental data. The optimized crystal structure of β-Cu2V2O7 indicates the existence of one-dimensional -Cu-Cu-Cu-Cu- chains. The electronic structure and magnetic properties were evaluated by the GGA+U calculations, which indicate that the β-Cu2V2O7 is a semiconducting antiferromagnetic material with an indirect band gap and local magnetic moment per Cu atom of 0.73μB . The intrachain exchanges for short and long Cu-Cu couples are estimated to be 6.4 and 4.1 meV, respectively, while the calculated interchain exchange (2.1 meV) is smaller, which indicate the one-dimensional character. The top of the valence band is composed of V3d , O2p , and Cu3d electrons while the bottom of the conduction band is primarily composed of Cu3d electrons. Valence electron-density distribution map indicates the V-O and Cu-O covalent bonds. Calculated partial electronic density of states strongly suggests that the V-O and Cu-O covalent bonds are mainly attributed to the overlaps of V3d and O2p atomic orbitals and of Cu3d and O2p , respectively.

  18. Monoclinic 122-Type BaIr2Ge2 with a Channel Framework: A Structural Connection between Clathrate and Layered Compounds

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    Xin Gui

    2017-07-01

    Full Text Available A new 122-type phase, monoclinic BaIr2Ge2 is successfully synthesized by arc melting; X-ray diffraction and scanning electron microscopy are used to purify the phase and determine its crystal structure. BaIr2Ge2 adopts a clathrate-like channel framework structure of the monoclinic BaRh2Si2-type, with space group P21/c. Structural comparisons of clathrate, ThCr2Si2, CaBe2Ge2, and BaRh2Si2 structure types indicate that BaIr2Ge2 can be considered as an intermediate between clathrate and layered compounds. Magnetic measurements show it to be diamagnetic and non-superconducting down to 1.8 K. Different from many layered or clathrate compounds, monoclinic BaIr2Ge2 displays a metallic resistivity. Electronic structure calculations performed for BaIr2Ge2 support its observed structural stability and physical properties.

  19. Optical, structural and fluorescence properties of nanocrystalline cubic or monoclinic Eu:Lu{sub 2}O{sub 3} films prepared by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Martinet, C. [Laboratoire de Physico-Chimie des Materiaux Luminescents, CNRS-Universite Lyon1, 10, rue Andre-Marie Ampere, 69622 Villeurbanne Cedex (France)]. E-mail: martinet@pcml.univ-lyon1.fr; Pillonnet, A. [Laboratoire de Physico-Chimie des Materiaux Luminescents, CNRS-Universite Lyon1, 10, rue Andre-Marie Ampere, 69622 Villeurbanne Cedex (France); Lancok, J. [Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 18221 Prague (Czech Republic); Garapon, C. [Laboratoire de Physico-Chimie des Materiaux Luminescents, CNRS-Universite Lyon1, 10, rue Andre-Marie Ampere, 69622 Villeurbanne Cedex (France)

    2007-10-15

    Eu{sup 3+}-doped lutetium oxide (Eu:Lu{sub 2}O{sub 3}) nanocrystalline films were grown on fused-silica substrates by pulsed laser deposition. Depending on deposition conditions (oxygen pressure, temperature and laser energy), the structure of the films changed from amorphous to crystalline and the cubic or monoclinic phases were obtained with varying preferential orientation and crystallite size. The monoclinic phase could be prepared for the first time at temperatures as low as 240 deg. C and in a narrow range of parameters. Although this phase has been previously reported for powder samples, it occurs only for high pressures and high temperatures preparation conditions. The refractive indices were measured by m-lines spectroscopy for both crystalline phases and their dispersion curve fitted by the Sellmeier expression. The specific Eu{sup 3+} fluorescence properties of the different phases, monoclinic and cubic, were registered and show modifications due to the disorder induced by the nanometric size of the crystallites, emphasised in particular by quasi-selective excitation in the charge transfer band.

  20. Monoclinic structure of hydroxylpyromorphite Pb10(PO4)6(OH)2 - hydroxylmimetite Pb10(AsO4)6(OH)2 solid solution series

    Science.gov (United States)

    Giera, Alicja; Manecki, Maciej; Borkiewicz, Olaf; Zelek, Sylwia; Rakovan, John; Bajda, Tomasz; Marchlewski, Tomasz

    2016-04-01

    Seven samples of hydroxyl analogues of pyromorphite-mimetite solid solutions series were synthesized from aqueous solutions at 80° C in a computer-controlled chemistate: 200 mL aqueous solutions of 0.05M Pb(NO3)2 and 0.03M KH2AsO4 and/or KH2PO4 were dosed with a 0.25 mL/min rate to a glass beaker, which initially contained 100 mL of distilled water. Constant pH of 8 was maintained using 2M KOH. The syntheses yielded homogeneous fine-grained white precipitates composition of which was close to theoretical Pb10[(PO4)6-x(AsO4)x](OH)2, where x = 0, 1, 2, 3, 4, 5, 6. High-resolution powder X-ray diffraction data were obtained in transmission geometry at the beamline 11-BM at the Advanced Photon Source (Argonne National Laboratory in Illinois, USA). The structure Rietveld refinements based on starting parameters of either hexagonal hydroxylpyromorphite or monoclinic mimetite-M were performed using GSAS+EXPGUI software. Apatite usually crystallizes in the hexagonal crystal system with the space group P63/m. For the first time, however, the lowering of the hexagonal to monoclinic crystal symmetry was observed in the hydroxyl variety of pyromorphite-mimetite solid solution series. This is indicated by better fitting of the modeled monoclinic structure to the experimental data. The same is not the case for analogous calcium hydroxylapatite series Ca5(PO4)3OH - Ca5(AsO4)3OH (Lee et al. 2009). Systematical linear increase of unit cell parameters is observed with As substitution from a=9.88, b=19.75, and c=7.43 for Pb10(PO4)6(OH)2 to a=10.23, b=20.32, and c=7.51 for Pb10(AsO4)6(OH)2. A strong pseudohexagonal character (γ ≈ 120° and b ≈ 2a) of the analyzed monoclinic phases was established. This work is partially funded by AGH research grant no 11.11.140.319 and partially by Polish NCN grant No 2011/01/M/ST10/06999. Lee Y.J., Stephens P.W., Tang Y., Li W., Philips B.L., Parise J.B., Reeder R.J., 2009. Arsenate substitution in hydroxylapatite: Structural characterization

  1. High-pressure syntheses and crystal structures of monoclinic B-Ho{sub 2}O{sub 3} and orthorhombic HoGaO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Hering, Stefanie A. [Dept. Chemie und Biochemie, Ludwig-Maximilians-Univ. Muenchen (Germany); Huppertz, Hubert [Inst. fuer Allgemeine, Anorganische und Theoretische Chemie, Leopold-Franzens-Univ. Innsbruck (Austria)

    2009-09-15

    Monoclinic holmium sesquioxide B-Ho{sub 2}O{sub 3} and orthorhombic holmium orthogallate HoGaO{sub 3} were synthesized in a Walker-type multianvil apparatus under high-pressure / high-temperature conditions of 11.5 GPa / 1250 C and 7.5 GPa / 1250 C, respectively. Both crystal structures could be determined by single-crystal X-ray diffraction data, collected at r.t. The monoclinic holmium oxide crystallizes in the space group C2/m (Z = 6) with the parameters a = 1394.7(3), b = 350.83(7), c = 865.6(2) pm, {beta} = 100.23(3) . R1 = 0.0517, wR2 = 0.1130 (all data), and the orthorhombic compound HoGaO{sub 3} in Pnma (Z = 4) with the parameters a = 553.0(2), b = 753.6(2), c = 525.4(2) pm. R1 = 0.0222, and wR2 = 0.0303 (all data). (orig.)

  2. Crystal structure of monoclinic samarium and cubic europium sesquioxides and bound coherent neutron scattering lengths of the isotopes {sup 154}Sm and {sup 153}Eu

    Energy Technology Data Exchange (ETDEWEB)

    Kohlmann, Holger [Leipzig Univ. (Germany). Inst. of Inorganic Chemistry; Hein, Christina; Kautenburger, Ralf [Saarland Univ., Saarbruecken (Germany). Inorganic Solid State Chemistry; Hansen, Thomas C.; Ritter, Clemens [Institut Laue-Langevin, Grenoble (France); Doyle, Stephen [Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany). Inst. for Synchrotron Radiation (ISS)

    2016-11-01

    The crystal structures of monoclinic samarium and cubic europium sesquioxide, Sm{sub 2}O{sub 3} and Eu{sub 2}O{sub 3}, were reinvestigated by powder diffraction methods (laboratory X-ray, synchrotron, neutron). Rietveld analysis yields more precise structural parameters than previously known, especially for oxygen atoms. Interatomic distances d(Sm-O) in Sm{sub 2}O{sub 3} range from 226.3(4) to 275.9(2) pm [average 241.6(3) pm] for the monoclinic B type Sm{sub 2}O{sub 3} [space group C2/m, a = 1418.04(3) pm, b = 362.660(7) pm, c = 885.48(2) pm, β = 100.028(1) ], d(Eu-O) in Eu{sub 2}O{sub 3} from 229.9(2) to 238.8(2) pm for the cubic bixbyite (C) type [space group Ia anti 3, a = 1086.87(1) pm]. Neutron diffraction at 50 K and 2 K did not show any sign for magnetic ordering in Sm{sub 2}O{sub 3}. Isotopically enriched {sup 154}Sm{sub 2}O{sub 3} and {sup 153}Eu{sub 2}O{sub 3} were used for the neutron diffraction work because of the enormous absorption cross section of the natural isotopic mixtures for thermal neutrons. The isotopic purity was determined by inductively coupled plasma - mass spectrometry to be 98.9% for {sup 154}Sm and 99.8% for {sup 153}Eu. Advanced analysis of the neutron diffraction data suggest that the bound coherent scattering lengths of {sup 154}Sm and {sup 153}Eu need to be revised. We tentatively propose b{sub c}({sup 154}Sm) = 8.97(6) fm and b{sub c}({sup 153}Eu) = 8.85(3) fm for a neutron wavelength of 186.6 pm to be better values for these isotopes, showing up to 8% deviation from accepted literature values. It is shown that inaccurate scattering lengths may result in severe problems in crystal structure refinements causing erroneous structural details such as occupation parameters, which might be critically linked to physical properties like superconductivity in multinary oxides.

  3. Density functional theory insights into the structural stability and Li diffusion properties of monoclinic and orthorhombic Li2FeSiO4 cathodes

    Science.gov (United States)

    Lu, Xia; Chiu, Hsien-Chieh; Bevan, Kirk H.; Jiang, De-Tong; Zaghib, Karim; Demopoulos, George P.

    2016-06-01

    Lithium iron orthosilicate (Li2FeSiO4) is an important alternative cathode for next generation Li-ion batteries due to its high theoretical capacity (330 mA h/g). However, its development has faced great challenges arising from significant structural complexity, including the disordered arrangement/orientation of Fe/Si tetrahedra, polytypes and its poorly understood Li storage and transport properties. In this context, ab-initio calculations are employed to investigate the phase stability and Li diffusion profiles of both monoclinic (P21) and orthorhombic (Pmn21) Li2FeSiO4 orthosilicates. The calculations demonstrate that formation of Lisbnd Fe antisites can induce a metastability competition between both phases, with neither dominating across nearly the entire discharging profile from Li2FeSiO4 through to LiFeSiO4. Furthermore, structural instability is shown to be a serious concern at discharge concentrations below LiFeSiO4 (1 Li extraction) due to the shared occupation of Li donated electrons with oxygen 2p orbitals - rather than the hypothesized transition to a tetravalent Fe4+ state. This finding is further supported by diffusion calculations that have determined a high activation energy barrier towards fast charging and rapid phase transitions. In summary, these theoretical results provide critical and timely insight into the structural dynamics of lithium iron orthosilicate, in pursuit of high energy density cathodes.

  4. Synthesis of monoclinic structured BiVO{sub 4} spindly microtubes in deep eutectic solvent and their application for dye degradation

    Energy Technology Data Exchange (ETDEWEB)

    Liu Wei, E-mail: weiliu@ouc.edu.cn [Institute of Materials Science and Engineering, Ocean University of China, Qingdao 266100 (China); Yu Yaqin; Cao Lixin; Su Ge; Liu Xiaoyun; Zhang Lan; Wang Yonggang [Institute of Materials Science and Engineering, Ocean University of China, Qingdao 266100 (China)

    2010-09-15

    Monoclinic structured spindly bismuth vanadate microtubes were fabricated on a large scale by a simple ionothermal treatment in the environment-friendly green solvent of urea/choline chloride. The as-prepared samples were characterized by XRD, SEM, TEM, IR and their photocatalytic activity was evaluated by photocatalytic decolorization of rhodamine B aqueous solution under visible-light irradiation. As-obtained BiVO{sub 4} microtubes exhibit the spindly shape with a side length of ca. 800 nm and a wall thickness of ca. 100 nm. The opening of these microtubes presents a saw-toothed structure, which is seldom in other tube-shaped materials. The formation mechanism of the spindly microtubes is ascribed to the complex cooperation of the reaction-crystallization process controlled by BiOCl and the nucleation-growth process of nanosheets induced by solvent molecules attached on the surface of microtubes. Such spindly microtubes exhibit much higher visible-light photocatalytic activity than that of bulk BiVO{sub 4} prepared by solid-state reaction, possibly resulting from their large surface area and improved crystallinity.

  5. A monoclinic polymorph of [(Z-N-(3-chlorophenyl-O-methylthiocarbamato-κS](triphenylphosphane-κPgold(I: crystal structure and Hirshfeld surface analysis

    Directory of Open Access Journals (Sweden)

    Chien Ing Yeo

    2016-08-01

    Full Text Available The title compound, [Au(C8H7ClNOS(C18H15P], is a monoclinic (P21/n, Z′ = 1; form β polymorph of the previously reported triclinic form (P-1, Z′ = 1; form α [Tadbuppa & Tiekink (2010. Acta Cryst. E66, m664]. The molecular structures of both forms feature an almost linear gold(I coordination geometry [P—Au—S = 175.62 (5° in the title polymorph], being coordinated by thiolate S and phosphane P atoms, a Z conformation about the C=N bond and an intramolecular Au...O contact. The major conformational difference relates to the relative orientations of the residues about the Au—S bond: the P—Au—S—C torsion angles are −8.4 (7 and 106.2 (7° in forms α and β, respectively. The molecular packing of form β features centrosymmetric aggregates sustained by aryl-C—H...O interactions, which are connected into a three-dimensional network by aryl-C—H...π contacts. The Hirshfeld analysis of forms α and β shows many similarities with the notable exception of the influence of C—H...O interactions in form β.

  6. Growth, structure, spectral properties and crystal-field analysis of monoclinic Nd:YNbO4 single crystal

    Science.gov (United States)

    Ding, Shoujun; Zhang, Qingli; Gao, Jinyun; Liu, Wenpeng; Luo, Jianqiao; Sun, Dunlu; Sun, Guihua; Wang, Xiaofei

    2016-12-01

    A Nd:YNbO4 single crystal was successfully grown by Czochralski (Cz) method, its structural and spectroscopic properties were investigated. The X-ray rocking curve of the (010) diffraction face of Nd:YNbO4 crystal was measured, the full width at half maximum (FWHM) of this diffraction peak is 0.05°, which indicates a high crystalline quality of the as-grown crystal. Its lattice parameters, atomic coordinates and so on were obtained by Rietvield refinement to X-ray diffraction data. According to the Archimedes drainage method, the crystal density of Nd:YNbO4 is calculated to be 5.4 g/cm3. The Mohr‧s hardness value along (010) face was determined to be 6.0. The transmission spectrum along (010) face at room temperature was recorded and the excitation and emission spectra at 8 K were measured. Photoluminescence peaks of Nd:YNbO4 were assigned, and the crystal-field splitting of Nd3+ in YNbO4 was obtained. The fluorescence lifetime of the 4F3/2→4I11/2 transition of Nd3+ in YNbO4 is fitted to be 152 μs These spectroscopic and energy splitting data give an important reference for the research of laser property of Nd:YNbO4 crystal.

  7. Growth, structure, spectral properties and crystal-field analysis of monoclinic Nd:YNbO{sub 4} single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Shoujun [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Key Laboratory of Photonic Devices and Materials, Hefei 230031 (China); University of Science and Technology of China, Hefei 230026 (China); Zhang, Qingli, E-mail: zql@aiofm.ac.cn [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Key Laboratory of Photonic Devices and Materials, Hefei 230031 (China); Gao, Jinyun; Liu, Wenpeng; Luo, Jianqiao; Sun, Dunlu; Sun, Guihua; Wang, Xiaofei [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Key Laboratory of Photonic Devices and Materials, Hefei 230031 (China)

    2016-12-15

    A Nd:YNbO{sub 4} single crystal was successfully grown by Czochralski (Cz) method, its structural and spectroscopic properties were investigated. The X-ray rocking curve of the (010) diffraction face of Nd:YNbO{sub 4} crystal was measured, the full width at half maximum (FWHM) of this diffraction peak is 0.05°, which indicates a high crystalline quality of the as-grown crystal. Its lattice parameters, atomic coordinates and so on were obtained by Rietvield refinement to X-ray diffraction data. According to the Archimedes drainage method, the crystal density of Nd:YNbO{sub 4} is calculated to be 5.4 g/cm{sup 3}. The Mohr′s hardness value along (010) face was determined to be 6.0. The transmission spectrum along (010) face at room temperature was recorded and the excitation and emission spectra at 8 K were measured. Photoluminescence peaks of Nd:YNbO{sub 4} were assigned, and the crystal-field splitting of Nd{sup 3+} in YNbO{sub 4} was obtained. The fluorescence lifetime of the {sup 4}F{sub 3/2}→{sup 4}I{sub 11/2} transition of Nd{sup 3+} in YNbO{sub 4} is fitted to be 152 μs These spectroscopic and energy splitting data give an important reference for the research of laser property of Nd:YNbO{sub 4} crystal.

  8. Monoclinic deformation of calcite crystals at ambient conditions

    Science.gov (United States)

    Przeniosło, R.; Fabrykiewicz, P.; Sosnowska, I.

    2016-09-01

    High resolution synchrotron radiation powder diffraction shows that the average crystal structure of calcite at ambient conditions is described with the trigonal space group R 3 bar c but there is a systematic hkl-dependent Bragg peak broadening. A modelling of this anisotropic peak broadening with the microstrain model from Stephens (1999) [15] is presented. The observed lattice parameters' correlations can be described by assuming a monoclinic-type deformation of calcite crystallites. A quantitative model of this monoclinic deformation observed at ambient conditions is described with the space group C 2 / c . The monoclinic unit cell suggested at ambient conditions is related with the monoclinic unit cell reported in calcite at high pressure (Merrill and Bassett (1975) [10]).

  9. Brazing titanium structures. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Pressly, H.B.

    1977-03-01

    A vacuum furnace brazing process using Ag-5A1-0.5Mn brazing alloy has been developed for joining titanium alloy Ti-6Al-4V structures. Lap-shear strengths of the braze joints and the effects of the brazing thermal cycle on the tensile and bending properties of mill-annealed Ti-6Al-4V alloy sheet are reported. Nondestructive test methods were evaluated for detecting defects in these braze joints.

  10. Novel monoclinic zirconolite in Bi{sub 2}O{sub 3}–CuO–Ta{sub 2}O{sub 5} ternary system: Phase equilibria, structural and electrical properties

    Energy Technology Data Exchange (ETDEWEB)

    Tan, K.B., E-mail: tankb@science.upm.my [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Chon, M.P. [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Khaw, C.C. [Department of Mechanical and Material Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, 53300 Setapak, Kuala Lumpur (Malaysia); Zainal, Z.; Taufiq Yap, Y.H.; Tan, P.Y. [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia)

    2014-04-01

    Highlights: • Novel BCT monoclinic zirconolite phase was prepared through solid state reaction. • Comprehensive study of reaction mechanism was performed by careful firing control. • Qualitative structural and phase analyses were conducted. • Electrical response in broad range of temperature and frequency was investigated. - Abstract: Synthesis of novel monoclinic zirconolite, Bi{sub 1.92}Cu{sub 0.08}(Cu{sub 0.3}Ta{sub 0.7}){sub 2}O{sub 7.06} (β-BCT) using solid state reaction had been finalised at the firing temperature of 900 °C over 24 h. The X–ray diffraction pattern of β-BCT was fully indexed on a monoclinic symmetry, space group, C2/c with lattice constants, a = 13.1052 (8), b = 7.6749 (5), c = 12.162 (6), α = γ = 90° and β = 101.32° (1), respectively. The reaction mechanism study indicated phase formation was greatly influenced by the reaction between intermediate bismuth tantalate binary phases and CuO at elevated temperatures. β-BCT was thermally stable up to a temperature of 900 °C and contained spherulite grains with sizes ranging from 1 to 14 μm. Electrical properties of this material were characterised over a broad temperature range covering temperatures from 10 K to 874 K. At the temperature of 304 K, two semicircles were discernible in complex Cole–Cole plot showing an insulating grain boundary with C{sub gb} = 6.63 × 10{sup −9} F cm{sup −1} and a bulk response capacitance, C{sub b} = 6.74 × 10{sup −12} F cm{sup −1}. The Power law frequency-dependent ac conductivity of β-BCT was apparent in three frequency regimes; a low–frequency plateau regime, a high-frequency plateau regime and a dispersive regime taking place in the temperature range of 220–576 K. The frequency-dependent ac conductivity of β-BCT with increasing temperature was attributed to the thermal activated electrical conduction mechanism within the structure.

  11. Non-laminate Microstructures in Monoclinic-I Martensite

    CERN Document Server

    Chenchiah, Isaac Vikram

    2012-01-01

    We study the symmetrised rank-one convex hull of monoclinic-I martensite (a twelve-variant material) in the context of geometrically-linear elasticity. We show that this hull is strictly larger than the symmetrised lamination convex hull by constructing sets of T3s, which are (non-trivial) symmetrised rank-one convex hulls of 3-tuples of pairwise incompatible strains. Moreover we construct a five-dimensional continuum of T3s and show that its intersection with the boundary of the symmetrised rank-one convex hull is four-dimensional. Along the way we show that there is another kind of monoclinic-I martensite with qualitatively different semi-convex hulls which, so far as we know, has not been experimentally observed. Our strategy is to combine understanding of the algebraic structure of symmetrised rank-one convex cones with knowledge of the faceting structure of the convex polytope formed by the strains.

  12. Non-Laminate Microstructures in Monoclinic-I Martensite

    Science.gov (United States)

    Chenchiah, Isaac Vikram; Schlömerkemper, Anja

    2013-01-01

    We study the symmetrised rank-one convex hull of monoclinic-I martensite (a twelve-variant material) in the context of geometrically-linear elasticity. We construct sets of T 3s, which are (non-trivial) symmetrised rank-one convex hulls of three-tuples of pairwise incompatible strains. In addition, we construct a fivedimensional continuum of T 3s and show that its intersection with the boundary of the symmetrised rank-one convex hull is four-dimensional.We also show that there is another kind of monoclinic-I martensite with qualitatively different semi-convex hulls which, as far as we know, has not been experimentally observed. Our strategy is to combine understanding of the algebraic structure of symmetrised rank-one convex cones with knowledge of the faceting structure of the convex polytope formed by the strains.

  13. Identification of monoclinic θ-phase dispersoids in a 6061 aluminium alloy

    Science.gov (United States)

    Buchanan, Karl; Ribis, Joël; Garnier, Jérôme; Colas, Kimberly

    2016-04-01

    Intermetallic dispersoids play an important role in controlling the 6xxx alloy series' grain distribution and increasing the alloy's toughness. The dispersoid distribution in a 6061 aluminium alloy (Al-Mg-Si) was analysed by transmission electron microscopy, selected area diffraction and energy-dispersive X-ray spectroscopy. The dispersoids had three unique crystal structures: simple cubic ?, body-centred cubic ? and monoclinic (C2/m). While the SC and BCC dispersoids have been well characterized in the literature, a detailed analysis of monoclinic dispersoids has not been presented. Therefore, the current work discusses the chemical composition, crystal structure and morphology of the monoclinic dispersoids.

  14. Synthesis of monoclinic zinc diphosphide single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Mowles, T.A.

    1978-05-01

    Monoclinic zinc diphosphide is a cheap, plentiful, direct-gap semiconductor with an optimum transition energy for solar absorption. Single crystals were grown from the vapor to be evaluated as a new photovoltaic material. Monoclinic and tetragonal crystal formed within evacuated quartz ampules that were charged with zinc and excess phosphorous and heated in a temperature gradient to give phosphorous pressures from 0.07 to 8.5 atmospheres. The monoclinic form melts incongruently near 990/sup 0/C. The tetragonal form is metastable; its growth is enhanced by impurities but retarded by high phosphorous pressures. The mechanism of the synthesis indicates that a tightly-controlled vapor deposition is possible and that high-quality thin films should form at temperatures from 950 to 990/sup 0/C at pressures below 10 atmospheres. By a modification of the technique, sesquizinc phosphide single crystals were grown for comparison.

  15. Phase coexistence in ferroelectric solid solutions: Formation of monoclinic phase with enhanced piezoelectricity

    Directory of Open Access Journals (Sweden)

    Xiaoyan Lu

    2016-10-01

    Full Text Available Phase morphology and corresponding piezoelectricity in ferroelectric solid solutions were studied by using a phenomenological theory with the consideration of phase coexistence. Results have shown that phases with similar energy potentials can coexist, thus induce interfacial stresses which lead to the formation of adaptive monoclinic phases. A new tetragonal-like monoclinic to rhombohedral-like monoclinic phase transition was predicted in a shear stress state. Enhanced piezoelectricity can be achieved by manipulating the stress state close to a critical stress field. Phase coexistence is universal in ferroelectric solid solutions and may provide a way to optimize ultra-fine structures and proper stress states to achieve ultrahigh piezoelectricity.

  16. Phase field modeling of tetragonal to monoclinic phase transformation in zirconia

    Science.gov (United States)

    Mamivand, Mahmood

    Zirconia based ceramics are strong, hard, inert, and smooth, with low thermal conductivity and good biocompatibility. Such properties made zirconia ceramics an ideal material for different applications form thermal barrier coatings (TBCs) to biomedicine applications like femoral implants and dental bridges. However, this unusual versatility of excellent properties would be mediated by the metastable tetragonal (or cubic) transformation to the stable monoclinic phase after a certain exposure at service temperatures. This transformation from tetragonal to monoclinic, known as LTD (low temperature degradation) in biomedical application, proceeds by propagation of martensite, which corresponds to transformation twinning. As such, tetragonal to monoclinic transformation is highly sensitive to mechanical and chemomechanical stresses. It is known in fact that this transformation is the source of the fracture toughening in stabilized zirconia as it occurs at the stress concentration regions ahead of the crack tip. This dissertation is an attempt to provide a kinetic-based model for tetragonal to monoclinic transformation in zirconia. We used the phase field technique to capture the temporal and spatial evolution of monoclinic phase. In addition to morphological patterns, we were able to calculate the developed internal stresses during tetragonal to monoclinic transformation. The model was started form the two dimensional single crystal then was expanded to the two dimensional polycrystalline and finally to the three dimensional single crystal. The model is able to predict the most physical properties associated with tetragonal to monoclinic transformation in zirconia including: morphological patterns, transformation toughening, shape memory effect, pseudoelasticity, surface uplift, and variants impingement. The model was benched marked with several experimental works. The good agreements between simulation results and experimental data, make the model a reliable tool for

  17. 2,3-Dibromo-3-phenylpropanoic acid: a monoclinic polymorph

    Directory of Open Access Journals (Sweden)

    Trent R. Howard

    2016-11-01

    Full Text Available Bromination of trans-cinnamic acid resulted in the formation of 2,3-dibromo-3-phenylpropanoic acid, C9H8Br2O2. Crystallization from ethanol–water (1:1 gave crystals of different shapes. One is in the form of rods, that crystallized as the orthorhombic polymorph (Pnma, and whose structure has been described [Thong et al. (2008. Acta Cryst. E64, o1946]. The other are thin plate-like crystals which are the monoclinic polymorph (P21/n. The structure of this monoclinic polymorph is similar to that of the orthorhombic polymorph; here the aliphatic C atoms are disordered over three sets of sites (occupancy ratio 0.5:0.25:0.25. In the crystal, molecules are linked by pairs of O—H...O hydrogen bonds, forming inversion dimers with an R22(8 ring motif. The dimers are linked by weak C—H...Br hydrogen bonds, forming chains propagating along the a-axis direction.

  18. Just How Final are Today's Quantum Structures?

    CERN Document Server

    Busch, P

    2001-01-01

    I present a selection of conceptual and mathematical problems in the foundations of modern physics as they derive from the title question. Contribution to a panel session, ``Springer Forum: Quantum Structures -- Physical, Mathematical and Epistemological Problems", held at the Biannual Symposium of the International Quantum Structures Association, Liptovsky Jan, September 1998. To appear in journal: Soft Computing (2001).

  19. 1-Nitro-4-(4-nitrophenoxybenzene: a second monoclinic polymorph

    Directory of Open Access Journals (Sweden)

    Arif Nadeem

    2013-12-01

    Full Text Available In the title compound, C12H8N2O5, the aromatic rings are inclined to one another by 56.14 (7°. The nitro groups are inclined by to the benzene rings to which they are attached by 3.86 (17 and 9.65 (15°. In the crystal, molecules are linked by C—H...O hydrogen bonds, forming a three-dimensional structure. The title compound is a new monoclinic polymorph, crystallizing in space group P21/c. The first polymorph crystallized in space group C2/c and the molecule possesses twofold rotation symmetry. Two low-temperature structures of this polymorph (150 K and 100 K, respectively have been reported [Meciarova et al. (2004. Private Communication (refcode IXOGAD. CCDC, Cambridge, England, and Dey & Desiraju (2005. Chem. Commun. pp. 2486–2488].

  20. 2-(4-Fluorobenzylidenepropanedinitrile: monoclinic polymorph

    Directory of Open Access Journals (Sweden)

    Ahmed M. El-Agrody

    2013-04-01

    Full Text Available The title compound, C10H5FN2, is a monoclinic (P21/c polymorph of the previously reported triclinic (P-1 form [Antipin et al. (2003. J. Mol. Struct. 650, 1–20]. The 13 non-H atoms in the title polymorph are almost coplanar (r.m.s. deviation = 0.020 Å; a small twist between the fluorobenzene and dinitrile groups [C—C—C—C torsion angle = 175.49 (16°] is evident in the triclinic polymorph. In the crystal, C—H...N interactions lead to supramolecular layers parallel to (-101; these are connected by C—F...π interactions.

  1. Post-patterning of an electronic homojunction in atomically thin monoclinic MoTe2

    Science.gov (United States)

    Kim, Sera; Kim, Jung Ho; Kim, Dohyun; Hwang, Geunwoo; Baik, Jaeyoon; Yang, Heejun; Cho, Suyeon

    2017-06-01

    Monoclinic group 6 transition metal dichalcogenides (TMDs) have been extensively studied for their intriguing 2D physics (e.g. spin Hall insulator) as well as for ohmic homojunction contacts in 2D device applications. A critical prerequisite for those applications is thickness control of the monoclinic 2D materials, which allows subtle engineering of the topological states or electronic bandgaps. Local thickness control enables the realization of clean homojunctions between different electronic states, and novel device operation in a single material. However, conventional fabrication processes, including chemical methods, typically produce non-homogeneous and relatively thick monoclinic TMDs, due to their distorted octahedral structures. Here, we report on a post-patterning technique using laser-irradiation to fabricate homojunctions between two different thickness areas in monoclinic MoTe2. A thickness-dependent electronic change from a metallic to semiconducting state, resulting in an electronic homojunction, was realized by the optical patterning of pristine MoTe2 flakes, and a pre-patterned device channel of monoclinic MoTe2 with a thickness-resolution of 5 nm. Our work provides insight on an optical post-process method for controlling thickness, as a promising approach for fabricating impurity-free 2D TMDs homojunction devices.

  2. Monoclinic zirconia distributions in plasma-sprayed thermal barrier coatings

    Science.gov (United States)

    Lance, M. J.; Haynes, J. A.; Ferber, M. K.; Cannon, W. R.

    2000-03-01

    Phase composition in an air plasma-sprayed Y2O3-stabilized ZrO2 (YSZ) top coating of a thermal barrier coating (TBC) system was characterized. Both the bulk phase content and localized pockets of monoclinic zirconia were measured with Raman spectroscopy. The starting powder consisted of ˜15 vol.% monoclinic zirconia, which decreased to ˜2 vol.% in the as-sprayed coating. Monoclinic zirconia was concentrated in porous pockets that were evenly distributed throughout the TBC. The pockets resulted from the presence of unmelted granules in the starting powder. The potential effect of the distributed monoclinic pockets on TBC performance is discussed.

  3. Structural engineering, mechanics and materials: Final report

    Energy Technology Data Exchange (ETDEWEB)

    1988-01-01

    This report on structural engineering, mechanics and materials is divided into three parts: a discussion on using Lanczos vectors and Ritz vectors for computing dynamic responses: solution of viscously damped linear systems using a finite element displacement formulation; and vibration analysis of fluid-solid systems using a finite element displacement formulation. (JF)

  4. Guideline based structured documentation: the final goal?

    Science.gov (United States)

    Bürkle, Thomas; Ganslandt, Thomas; Tübergen, Dirk; Menzel, Josef; Kucharzik, Torsten; Neumann, Klaus; Schlüter, Stefan; Müller, Marcel; Veltmann, Ursula; Prokosch, Hans-Ulrich

    2002-01-01

    Structured documentation of medical procedures facilitates information retrieval for research and therapy and may help to improve patient care. Most medical documents until today however consist mainly of unstructured narrative text. Here we present an application for endoscopy which is not only fully integrated into a comprehensive clinical information system, but which also supports various degrees of structuring examination reports. The application is used routinely in a German University hospital since summer 2000. We present the first unstructured version which permits storage of a free text report together with selected examination images. The next step added improved structure to the document using a catalogue of index terms. The practical advantages of selective patient retrieval are described. Today we use a version which supports fully structured, guideline based documentation of endoscopy reports in order to automatically generate essential classification codes and the narrative examination report All versions have advantages and disadvantages and we conclude that guideline based documentation may not be suitable for all endoscopy cases.

  5. Investigation of coal structure. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Nishioka, Masaharu

    1994-03-01

    A better understanding of coal structure is the first step toward more effective utilization of the most abundant hydrocarbon resource. Detailed characterization of coal structure is very difficult, even with today`s highly developed analytical techniques. This is primarily due to the amorphous nature of these high-molecular-weight mixtures. Coal has a polymeric character and has been popularly represented as a three-dimensional cross-linked network. There is, however, little or no information which positively verifies this model. The principal objective of this research was to further investigate the physical structure of coal and to determine the extent to which coal molecules may be covalently cross-linked and/or physically associated. Two common characterization methods, swellability and extractability, were used. A technique modifying the conventional swelling procedure was established to better determine network or associated model conformation. A new method for evaluating coal swelling involving laser scattering has also been developed. The charge-transfer interaction is relatively strong in high-volatile bituminous coal. Soaking in the presence of electron donors and acceptors proved effective for solubilizing the coal, but temperatures in excess of 200 C were required. More than 70 wt% of the coal was readily extracted with pyridine after soaking. Associative/dissociative equilibria of coal molecules were observed during soaking. From these results, the associated model has gained credibility over the network model as the representative structure of coal. Significant portions of coal molecules are unquestionably physically associated, but the overall extent is not known at this time.

  6. Investigation of Nuclear Partonic Structure. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, Henry J. [Univ. of California, Berkeley, CA (United States); Engelage, J. M.

    2016-08-30

    Our research program had two primary goals during the period of this grant, to search for new and rare particles produced in high-energy nuclear collisions and to understand the internal structure of nuclear matter. We have developed electronics to pursue these goals at the Relativistic Heavy Ion Collider (RHIC) in the Solenoidal Tracker at RHIC (STAR) experiment and the AnDY experiment. Our results include discovery of the anti-hyper-triton, anti- 3Λ-barH, which opened a new branch on the chart of the nuclides, and the anti-alpha, anti- 4He, the heaviest form of anti-matter yet seen, as well as uncovering hints of gluon saturation in cold nuclear matter and observation of jets in polarized proton-proton collisions that will be used to probe orbital motion inside protons.

  7. Insulating Structural Ceramics Program, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, Mark J.; Tandon, Raj; Ott, Eric; Hind, Abi Akar; Long, Mike; Jensen, Robert; Wheat, Leonard; Cusac, Dave; Lin, H. T.; Wereszczak, Andrew A.; Ferber, Mattison K.; Lee, Sun Kun; Yoon, Hyung K.; Moreti, James; Park, Paul; Rockwood, Jill; Boyer, Carrie; Ragle, Christie; Balmer-Millar, Marilou; Aardahl, Chris; Habeger, Craig; Rappe, Ken; Tran, Diana; Koshkarian, Kent; Readey, Michael

    2005-11-22

    New materials and corresponding manufacturing processes are likely candidates for diesel engine components as society and customers demand lower emission engines without sacrificing power and fuel efficiency. Strategies for improving thermal efficiency directly compete with methodologies for reducing emissions, and so the technical challenge becomes an optimization of controlling parameters to achieve both goals. Approaches being considered to increase overall thermal efficiency are to insulate certain diesel engine components in the combustion chamber, thereby increasing the brake mean effective pressure ratings (BMEP). Achieving higher BMEP rating by insulating the combustion chamber, in turn, requires advances in material technologies for engine components such as pistons, port liners, valves, and cylinder heads. A series of characterization tests were performed to establish the material properties of ceramic powder. Mechanical chacterizations were also obtained from the selected materials as a function of temperature utilizing ASTM standards: fast fracture strength, fatique resistance, corrosion resistance, thermal shock, and fracture toughness. All ceramic materials examined showed excellent wear properties and resistance to the corrosive diesel engine environments. The study concluded that the ceramics examined did not meet all of the cylinder head insert structural design requirements. Therefore we do not recommend at this time their use for this application. The potential for increased stresses and temperatures in the hot section of the diesel engine combined with the highly corrosive combustion products and residues has driven the need for expanded materials capability for hot section engine components. Corrosion and strength requirements necessitate the examination of more advanced high temperture alloys. Alloy developments and the understanding of processing, structure, and properties of supperalloy materials have been driven, in large part, by the gas

  8. Bis[2-(hydroxyiminomethylphenolato]nickel(II: a second monoclinic polymorph

    Directory of Open Access Journals (Sweden)

    Julia A. Rusanova

    2011-02-01

    Full Text Available The title compound, [Ni(C7H6NO22], (I, is a second monoclinic polymorph of the compound, (II, reported by Srivastava et al. [Acta Cryst. (1967, 22, 922] and Mereiter [Private communication (2002 CCDC refcode NISALO01]. The bond lengths and angles are similar in both structures. The molecule in both structures lies on a crystallographic inversion center and both have an internal hydrogen bond. The title compound crystallizes in the space group P21/c (Z = 2, whereas compound (II is in the space group P21/n (Z = 2 with a similar cell volume but different cell parameters. In both polymorphs, molecules are arranged in the layers but in contrast to the previously published compound (II where the dihedral angle between the layers is 86.3°, in the title polymorph the same dihedral angle is 29.4°. The structure of (I is stabilized by strong intramolecular O—H...O hydrogen bonding between the O—H group and the phenolate O atom.

  9. Strong Bilayer Coupling Induced by the Symmetry Breaking in the Monoclinic Phase of BiS2-Based Superconductors

    Science.gov (United States)

    Ochi, Masayuki; Akashi, Ryosuke; Kuroki, Kazuhiko

    2016-09-01

    We perform first-principles band structure calculations for the tetragonal and monoclinic structures of LaO0.5F0.5BiS2. We find that the Bi 6px,y bands on two BiS2 layers exhibit a sizable splitting at the X = (π ,0,0) and several other k-points for the monoclinic structure. We show that this feature originates from the inter-BiS2 layer coupling strongly enhanced by the symmetry breaking of the crystal structure. The Fermi surface also shows a large splitting and becomes anisotropic with respect to the kx- and ky-directions in the monoclinic structure, whereas it remains almost flat with respect to the kz-direction.

  10. What causes the Besnus transition in monoclinic pyrrhotite?

    Science.gov (United States)

    Gehring, A. U.; Koulialias, D.; Löffler, J. F.; Charilaou, M.

    2016-12-01

    Monoclinic 4C pyrrhotite (ideal formula Fe7S8) is a major magnetic remanence carrier in the Earth's crust and in extraterrestrial materials. Because of its low-temperature magnetic transition around 30 K also known as Besnus transition, this mineral phase is easily detectable in rock samples. An intrinsic origin of the Besnus transition due to a crystallographic change similar to that in the Verwey transition has generally been postulated (1). Although the physical properties of pyrrhotite have intensively been studied, the physics behind the pronounced change in magnetization at the low-temperature transition is still unresolved. To address this question we performed structural and magnetic analyses on a natural pyrrhotite single crystal (Fe6.6S8) from Auerbach, Germany (2,3). Chemical analysis, X-ray diffractometry and transmission electron microscopy show that this pyrrhotite consists of an intergrowth of 4C and an incommensurate 5C* superstructure that are polymorphs with different vacancy distributions. The occurrence of two superstructures is magnetically confirmed by symmetric inflection points in the hysteresis measurements above the transition at about 30 K. The disappearance of the inflection points and the associated change of the hysteresis parameters indicate that the two superstructures become embedded to form a unitary magnetic anisotropy system at the transition. This embedding of the 5C* into the 4C pyrrhotite at about 30 K is directly visible by the occurrence of additional 4-fold and 12-fold symmetry terms in magnetic anisotropy and anisotropic magnetic resistivity mesarurements, respectively. From this it follows that the Besnus transition in monoclinic pyrrhotite is an extrinsic magnetic phenomenon with respect to the 4C superstructure, i.e., a coupling effect, and therefore the physics behind it is in fact different from that of the well-known Verwey transition. (1) Rochette et al., The IRM Quarterly, 21, 1 (2011); (2) Charilaou et al., J

  11. Proton ordering in tetragonal and monoclinic H2O ice

    CERN Document Server

    Yen, Fei; Berlie, Adam; Liu, Xiaodi; Goncharov, Alexander F

    2015-01-01

    H2O ice remains one of the most enigmatic materials as its phase diagram reveals up to sixteen solid phases. While the crystal structure of these phases has been determined, the phase boundaries and mechanisms of formation of the proton-ordered phases remain unclear. From high precision measurements of the complex dielectric constant, we probe directly the degree of ordering of the protons in H2O tetragonal ice III and monoclinic ice V down to 80 K. A broadened first-order phase transition is found to occur near 202 K we attribute to a quenched disorder of the protons which causes a continuous disordering of the protons during cooling and metastable behavior. At 126 K the protons in ice III become fully ordered, and for the case of ice V becoming fully ordered at 113 K forming ice XIII. Two triple points are proposed to exist: one at 0.35 GPa and 126 K where ices III, IX and V coexist; and another at 0.35 GPa and 113 K where ices V, IX and XIII coexist. Our findings unravel the underlying mechanism driving th...

  12. Evidence for photo-induced monoclinic metallic VO{sub 2} under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Wen-Pin, E-mail: wphsieh@stanford.edu; Mao, Wendy L. [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305 (United States); Trigo, Mariano [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Reis, David A. [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Photon Science and Applied Physics, Stanford University, Stanford, California 94305 (United States); Andrea Artioli, Gianluca; Malavasi, Lorenzo [Dipartimento di Chimica, Sezione di Chimica Fisica, INSTM (UdR Pavia), Università di Pavia, Viale Taramelli 16, 27100 Pavia (Italy)

    2014-01-13

    We combine ultrafast pump-probe spectroscopy with a diamond-anvil cell to decouple the insulator-metal electronic transition from the lattice symmetry changing structural transition in the archetypal strongly correlated material vanadium dioxide. Coherent phonon spectroscopy enables tracking of the photo-excited phonon vibrational frequencies of the low temperature, monoclinic (M{sub 1})-insulating phase that transforms into the metallic, tetragonal rutile structured phase at high temperature or via non-thermal photo-excitations. We find that in contrast with ambient pressure experiments where strong photo-excitation promptly induces the electronic transition along with changes in the lattice symmetry, at high pressure, the coherent phonons of the monoclinic (M{sub 1}) phase are still clearly observed upon the photo-driven phase transition to a metallic state. These results demonstrate the possibility of synthesizing and studying transient phases under extreme conditions.

  13. Seismic Data Interpretation: A Case Study of Southern Sindh Monocline, Lower Indus Basin, Pakistan

    Directory of Open Access Journals (Sweden)

    Shabeer Ahmed Abbasi

    2015-04-01

    Full Text Available The Sindh monocline in Lower Indus Basin is an important oil and gas producing area of Pakistan where a large number of oil, gas and condensate fields have been discovered from structural traps. This research involves the interpretation of stratigraphic and structural styles of Sindh Monocline using 2D (Two-Dimensional seismic reflection and well log. Four reflectors of different formations have been marked and were named as Reflector-1 as of Khadro Formation, Reflector-2 as Upper Goru Member, Reflector-3 as Lower Goru Formation and Reflector-4 as Chiltan Limestone. The average depth of Khadro Formation was marked at 449.0m, Upper Goru Member at 968m, Lower Goru Formation at 1938m and Chiltan Limestone at 2943m. Faults were marked on seismic sections which collectively form horsts and grabens which is the evidence of extensional tectonic in the area. Seismic interpretation was carried out through window based Kingdom Software

  14. Critical Role of Monoclinic Polarization Rotation in High-Performance Perovskite Piezoelectric Materials

    Science.gov (United States)

    Liu, Hui; Chen, Jun; Fan, Longlong; Ren, Yang; Pan, Zhao; Lalitha, K. V.; Rödel, Jürgen; Xing, Xianran

    2017-07-01

    High-performance piezoelectric materials constantly attract interest for both technological applications and fundamental research. The understanding of the origin of the high-performance piezoelectric property remains a challenge mainly due to the lack of direct experimental evidence. We perform in situ high-energy x-ray diffraction combined with 2D geometry scattering technology to reveal the underlying mechanism for the perovskite-type lead-based high-performance piezoelectric materials. The direct structural evidence reveals that the electric-field-driven continuous polarization rotation within the monoclinic plane plays a critical role to achieve the giant piezoelectric response. An intrinsic relationship between the crystal structure and piezoelectric performance in perovskite ferroelectrics has been established: A strong tendency of electric-field-driven polarization rotation generates peak piezoelectric performance and vice versa. Furthermore, the monoclinic MA structure is the key feature to superior piezoelectric properties as compared to other structures such as monoclinic MB , rhombohedral, and tetragonal. A high piezoelectric response originates from intrinsic lattice strain, but little from extrinsic domain switching. The present results will facilitate designing high-performance perovskite piezoelectric materials by enhancing the intrinsic lattice contribution with easy and continuous polarization rotation.

  15. Fabrication and photoelectrocatalytic properties of nanocrystalline monoclinic BiVO4 thin-film electrode.

    Science.gov (United States)

    Zhou, Bin; Qu, Jiuhui; Zhao, Xu; Liu, Huijuan

    2011-01-01

    Monoclinic bismuth vanadate (BiVO4) thin film was fabricated on indium-tin oxide glass from an amorphous heteronuclear complex via dip-coating. After annealation at 400, 500, and 600 degrees C, the thin films were characterized by X-ray diffraction, field emission scanning electron microscopy, X-ray photoelectron spectroscopy, and UV-Vis spectrophotometry. The BiVO4 particles on the ITO glass surface had a monoclinic structure. The UV-Visible diffuse reflection spectra showed the BiVO4 thin film had photoabsorption properties, with a band gap around 2.5 eV. In addition, the thin film showed high visible photocatalytic activities towards 2,4-dichlorophenol and Bisphenol A degradation under visible light irradiation (lambda > 420 nm). Over 90% of the two organic pollutants were removed in 5 hr. A possible degradation mechanism of 2,4-dichlorophenol were also studied.

  16. Fabrication and photoelectrocatalytic properties of nanocrystalline monoclinic BiVO4 thin-film electrode

    Institute of Scientific and Technical Information of China (English)

    Bin Zhou; Jiuhui Qu; Xu Zhao; Huijuan Liu

    2011-01-01

    Monoclinic bismuth vanadate (BiVO4) thin film was fabricated on indium-tin oxide glass from an amorphous heteronuclear complex via dip-coating.After annealation at 400, 500, and 600℃, the thin films were characterized by X-ray diffraction, field emission scanning electron microscopy, X-ray photoelectron spectroscopy, and UV-Vis spectrophotometry.The BiVO4 particles on the ITO glass surface had a monoclinic structure.The UV-Visible diffuse reflection spectra showed the BiVO4 thin film had photoabsorption properties, with a band gap around 2.5 eV.In addition, the thin film showed high visible photocatalytic activities towards 2,4-dichiorophenol and Bisphenol A degradation under visible light irradiation (λ.> 420 nm).Over 90% of the two organic pollutants were removed in 5 hr.A possible degradation mechanism of 2,4-dichlorophenol were also studied.

  17. Prediction of a novel monoclinic carbon allotrope

    Science.gov (United States)

    Amsler, Maximilian; Flores-Livas, José A.; Marques, Miguel A. L.; Botti, Silvana; Goedecker, Stefan

    2013-09-01

    A novel allotrope of carbon with P2/ m symmetry was identified during an ab initio minima-hopping structural search which we call M10-carbon. This structure is predicted to be more stable than graphite at pressures above 14.4 GPa and consists purely of s p 3 bonds. It has a high bulk modulus and is almost as hard as diamond. A comparison of the simulated X-ray diffraction pattern shows a good agreement with experimental results from cold compressed graphite.

  18. Metastable monoclinic ZnMoO4: hydrothermal synthesis, optical properties and photocatalytic performance.

    Science.gov (United States)

    Lv, Li; Tong, Wenming; Zhang, Yanbing; Su, Yiguo; Wang, Xiaojing

    2011-11-01

    Metastable monoclinic ZnMoO4 was successfully synthesized via a hydrothermal route with variation of reaction temperatures and time at pH value of 5.7. Systematic sample characterizations were carried out, including X-ray powder diffraction, scanning electron microscopy, Fourier transformed infrared spectra, UV-visible diffuse reflectance spectra, and photoluminescence spectra. The results show that all as-prepared ZnMoO4 samples were demonstrated to crystallize in a pure-phase of monoclinic wolframite structure. All samples were formed in plate-like morphology. Six IR active vibrational bands were observed in the wave number range of 400-900 cm(-1). The band gap of as-prepared ZnMoO4 was estimated to be 2.86 eV by Tauc equation. Photoluminescence measurement indicates that as-prepared ZnMoO4 exhibits a broad blue-green emission under excitation wavelength of 280 nm at room temperature. Photocatalytic activity of as-prepared ZnMoO4 was examined by monitoring the degradation of methyl orange dye in an aqueous solution under UV radiation of 365 nm. The as-prepared ZnMoO4 obtained at 180 degrees C for 40 h showed the best photocatalytic activity with completing degradation of MO in irradiation time of 120 min. Consequently, monoclinic ZnMoO4 proved to be an efficient near visible light photocatalyst.

  19. Stability of the monoclinic phase in the ferroelectric perovskite PbZr1-xTixO3

    NARCIS (Netherlands)

    Noheda, B.; Cox, D.E.; Shirane, G.; Guo, R.; Jones, B.; Cross, L.E.

    2000-01-01

    Recent structural studies of ferroelectric PbZr1-xTixO3 (PZT) with x=0.48, have revealed a monoclinic phase in the vicinity of the morphotropic phase boundary (MPB), previously regarded as the boundary separating the rhombohedral and tetragonal regions of the PZT phase diagram. In the present paper,

  20. Interaction between Syntactic Structure and Information Structure in the Processing of a Head-Final Language

    Science.gov (United States)

    Koizumi, Masatoshi; Imamura, Satoshi

    2017-01-01

    The effects of syntactic and information structures on sentence processing load were investigated using two reading comprehension experiments in Japanese, a head-final SOV language. In the first experiment, we discovered the main effects of syntactic and information structures, as well as their interaction, showing that interaction of these two…

  1. Atomic Origins of Monoclinic-Tetragonal (Rutile) Phase Transition in Doped VO 2 Nanowires

    KAUST Repository

    Asayesh-Ardakani, Hasti

    2015-10-12

    There has been long-standing interest in tuning the metal-insulator phase transition in vanadium dioxide (VO) via the addition of chemical dopants. However, the underlying mechanisms by which doping elements regulate the phase transition in VO are poorly understood. Taking advantage of aberration-corrected scanning transmission electron microscopy, we reveal the atomistic origins by which tungsten (W) dopants influence the phase transition in single crystalline WVO nanowires. Our atomically resolved strain maps clearly show the localized strain normal to the (122¯) lattice planes of the low W-doped monoclinic structure (insulator). These strain maps demonstrate how anisotropic localized stress created by dopants in the monoclinic structure accelerates the phase transition and lead to relaxation of structure in tetragonal form. In contrast, the strain distribution in the high W-doped VO structure is relatively uniform as a result of transition to tetragonal (metallic) phase. The directional strain gradients are furthermore corroborated by density functional theory calculations that show the energetic consequences of distortions to the local structure. These findings pave the roadmap for lattice-stress engineering of the MIT behavior in strongly correlated materials for specific applications such as ultrafast electronic switches and electro-optical sensors.

  2. Solid State Synthesis and Properties of Monoclinic Celsian

    Science.gov (United States)

    Bansal, Narottam P.

    1996-01-01

    Monoclinic celsian of Ba(0.75)Sr(0.25)Al2Si2O8 (BSAS-1) and B(0.85)Sr(O.15)Al2Si2O8 (BSAS-2) compositions have been synthesized from metal carbonates and oxides by solid state reaction. A mixture of BaCO3, SrCO3, Al2O3, and SiO2 powders was precalcined at approx. 900-940 C to decompose the carbonates followed by hot pressing at approx. 1300 C. The hot pressed BSAS-1 material was almost fully dense and contained the monoclinic celsian phase, with complete absence of the undesirable hexacelsian as indicated by x-ray diffraction. In contrast, a small fraction of hexacelsian was still present in hot pressed BSAS-2. However, on further heat treatment at 1200 C for 24 h, the hexacelsian phase was completely eliminated. The average linear thermal expansion coefficients of BSAS-1 and BSAS-2 compositions, having the monoclinic celsian phase, were measured to be 5.28 x 10(exp -6)/deg C and 5.15 x 10(exp -6)/deg C, respectively from room temperature to 1200 C. The hot pressed BSAS-1 celsian showed room temperature flexural strength of 131 MPa, elastic modulus of 96 GPa and was stable in air up to temperatures as high as approx. 1500 C.

  3. Template-Engaged In Situ Synthesis of Carbon-Doped Monoclinic Mesoporous BiVO4: Photocatalytic Treatment of Rhodamine B

    Science.gov (United States)

    Yao, Mingming; Gan, Lihua; Liu, Mingxian; Tripathi, Pranav K.; Liu, Yafei; Hu, Zhonghua

    2015-06-01

    In this paper, carbon-doped monoclinic scheelite mesoporous bismuth vanadate was synthesized through template-engaged in situ method. The bismuth nitrate pentahydrate and ammonia metavanadate were used as bismuth and vanadium precursors, respectively, glucose as carbon source, and mesoporous SiO2 aerogel as a hard template. Carbon-doped monoclinic mesoporous BiVO4 were obtained by heat treatment of BiVO4/glucose/template to carbonize glucose and form monoclinic crystal, followed by etching with NaOH solution to remove the SiO2 template. The samples were characterized by x-ray diffraction, N2 adsorption and desorption, UV-visible spectroscopy, Energy dispersive spectrometry, Raman spectroscopy, and Transmission electron microscopy. It was found that the sample with a carbon content of 0.5 wt.% possesses a specific surface area of 10.2 m2/g and has mesoporous structure with the most probable pore size of 13.9 nm. The band gap of carbon-doped monoclinic mesoporous BiVO4 was estimated to be 2.33 eV, indicating the superior photocatalytic activity under visible light. The photocatalytic efficiency of carbon-doped monoclinic mesoporous BiVO4 for the degradation of Rhodamine B under visible light (λ > 400 nm) in 120 min reaches 98.7%, Besides, the carbon-doped monoclinic mesoporous BiVO4 photocatalyst still showed high stability: 85% for Rhodamine B degradation after ten recycles.

  4. Thermal Hydrolysis Synthesis and Characterization of Monoclinic Metahewettite CaV6O16•3H2O

    Institute of Scientific and Technical Information of China (English)

    LI Lanjie; ZHENG Shili; WANG Shaona; DU Hao; ZHANG Yi

    2014-01-01

    Monoclinic metahewettite CaV6O16•3H2O has been fabricated via thermal hydrolysis of calcium vanadate (Ca10V6O25). High purity calcium vanadate precipitate, featuring column structure with surface area of 8.61 m2/g, can be obtained by reacting sodium orthovanadate (Na3VO4) with calcium oxide at 90℃for 2 h. By acidification of calcium vanadate in hot water at pH of 1.0-3.0, the monoclinic metahewettite crystals with uniform particle distribution, layered structure and nonporous structure can be fabricated. With the well crystallized layered structure, CaV6O16•3H2O may be a potential cathode material for secondary batteries as well as super capacitor materials.

  5. Ab initio velocity-field curves in monoclinic β-Ga2O3

    Science.gov (United States)

    Ghosh, Krishnendu; Singisetti, Uttam

    2017-07-01

    We investigate the high-field transport in monoclinic β-Ga2O3 using a combination of ab initio calculations and full band Monte Carlo (FBMC) simulation. Scattering rate calculation and the final state selection in the FBMC simulation use complete wave-vector (both electron and phonon) and crystal direction dependent electron phonon interaction (EPI) elements. We propose and implement a semi-coarse version of the Wannier-Fourier interpolation method [Giustino et al., Phys. Rev. B 76, 165108 (2007)] for short-range non-polar optical phonon (EPI) elements in order to ease the computational requirement in FBMC simulation. During the interpolation of the EPI, the inverse Fourier sum over the real-space electronic grids is done on a coarse mesh while the unitary rotations are done on a fine mesh. This paper reports the high field transport in monoclinic β-Ga2O3 with deep insight into the contribution of electron-phonon interactions and velocity-field characteristics for electric fields ranging up to 450 kV/cm in different crystal directions. A peak velocity of 2 × 107 cm/s is estimated at an electric field of 200 kV/cm.

  6. Seismic transpressive basement faults and monocline development in a foreland basin (Eastern Guadalquivir, SE Spain)

    Science.gov (United States)

    Pedrera, A.; Ruiz-Constán, A.; Marín-Lechado, C.; Galindo-Zaldívar, J.; González, A.; Peláez, J. A.

    2013-12-01

    We examine the late Tortonian to present-day deformation of an active seismic sector of the eastern Iberian foreland basement of the Betic Cordillera, in southern Spain. Transpressive faults affecting Paleozoic basement offset up to Triassic rocks. Late Triassic clays and evaporites constitute a décollement level decoupling the basement rocks and a ~100 m thick cover of Jurassic carbonates. Monoclines trending NE-SW to ENE-WSW deform the Jurassic cover driven by the propagation of high-angle transpressive right-lateral basement faults. They favor the migration of clays and evaporites toward the propagated fault tip, i.e., the core of the anticline, resulting in fluid overpressure, fluid flow, and precipitation of fibrous gypsum parallel to a vertical σ3. The overall geometry of the studied monoclines, as well as the intense deformation within the clays and evaporites, reproduces three-layer discrete element models entailing a weak middle unit sandwiched between strong layers. Late Tortonian syn-folding sediments recorded the initial stages of the fault-propagation folding. Equivalent unexposed transpressive structures and associated monoclines reactivated under the present-day NW-SE convergence are recognized and analyzed in the Sabiote-Torreperogil region, using seismic reflection, gravity, and borehole data. A seismic series of more than 2100 low-magnitude earthquakes was recorded within a very limited area of the basement of this sector from October 2012 to May 2013. Seismic activity within a major NE-SW trending transpressive basement fault plane stimulated rupture along a subsidiary E-W (~N95°E) strike-slip relay fault. The biggest event (mbLg 3.9, MW 3.7) occurred at the junction between them in a transpressive relay sector.

  7. Synthesis and characterization of monoclinic TiO2 nanosheets

    Institute of Scientific and Technical Information of China (English)

    WU Yu; XU Boqing

    2005-01-01

    A novel two-step method for the synthesis of monoclinic titanium oxide (i.e. TiO2(B)) nanosheets is presented in this report. The method is featured by two steps: 1) synthesis of hydrogen titanate nanosheets, followed by 2) calcination of the titanate nanosheets at elevated temperatures. The hydrogen titanate nanosheets were prepared first by autoclaving anatase TiO2 powders, obtained by air calcining an ethanol-gel of Ti(OH)4 at 500℃, in aqueous NaOH (10 mol/L) at 150―200℃, and then by washing with hydrochloric acid under supersonic irradiation. While sizes of the nanosheets were found to increase with increasing the temperature of the hydrothermal treatment, the calcination at 400―500℃ of the hydrogen titanate nanosheets that were synthesized at higher autoclaving temperatures (180―200℃) produced monoclinic TiO2 nanosheets with a uniform morphology. By contrast, the same calcination of the titanate nanosheets synthesized at the autoclaving temperature 180℃ led to anatase TiO2 nanoparticles.

  8. Dynamic Heterogeneity In The Monoclinic Phase Of CCl$_4$

    CERN Document Server

    Caballero, Nirvana B; Carignano, Marcelo; Serra, Pablo

    2016-01-01

    Carbon tetrachloride (CCl$_4$) is one of the simplest compounds having a translationally stable monoclinic phase while exhibiting a rich rotational dynamics below 226 K. Recent nuclear quadrupolar resonance (NQR) experiments revealed that the dynamics of CCl$_4$ is similar to that of the other members of the isostructural series CBr$_{n}$Cl$_{4-n}$, suggesting that the universal relaxation features of canonical glasses such as $\\alpha$- and $\\beta$-relaxation are also present in non-glass formers. Using molecular dynamics (MD) simulations we studied the rotational dynamics in the monoclinic phase of CCl$_4$. The molecules undergo $C3$ type jump-like rotations around each one of the four C-Cl bonds. The rotational dynamics is very well described with a master equation using as the only input the rotational rates measured from the simulated trajectories. It is found that the heterogeneous dynamics emerges from faster and slower modes associated with different rotational axes, which have fixed orientations relat...

  9. Final design of the generic upper port plug structure for ITER diagnostic systems

    NARCIS (Netherlands)

    Pak, S.; Feder, R.; Giacomin, T.; Guirao, J.; Iglesias, S.; Josseaume, F.; Kalish, M.; Loesser, D.; Maquet, P.; Ronden, D.; Ordieres, J.; Panizo, M.; Pitcher, S.; M. Portalès,; Proust, M.; Serikov, A.; Suarez, A.; Tanchuk, V.; Udintsev, V.; Vacas, C.; Walsh, M.; Zhai, Y.

    2016-01-01

    The generic upper port plug (GUPP) structure in ITER is a 6 m long metal box which deploys diagnostic components into the vacuum vessel. This structure is commonly used for all the diagnostic upper ports. The final design of the GUPP structure, which has successfully passed the final design review i

  10. Analysis of tetragonal to monoclinic phase transformation caused by accelerated artificial aging and the effects of microstructure in stabilized zirconia

    Science.gov (United States)

    Lucas, Thomas J.

    This investigation addresses the issue that yttria stabilized zirconia is being used as a dental biomaterial without substantial evidence of its long-term viability. Furthermore, stabilized zirconia (SZ) undergoes low temperature degradation (LTD), which can lead to roughening of the surface. A rougher exterior can lead to increased wear of the antagonist in the oral environment. Despite the LTD concerns, SZ is now widely used in restorative dentistry, including full contour crowns. A comparison of aging methods to determine the role of artificial aging on inducing the transformation has not been extensively studied. Therefore, simulations of the transformation process were investigated by comparing different methods of accelerated aging. The rejected null hypothesis is that the temperature of aging treatment will not affect the time required to cause measurable monoclinic transformation of yttria stabilized zirconia. The transformation of SZ starts at the surface and progresses inward; however, it is unclear whether the progression is constant for different aging conditions. This investigation analyzed the depth of transformation as a function of aging conditions for stabilized zirconia in the top 5-6 mum from the surface. The rejected null hypothesis is that the transformation amount is constant throughout the first six micrometers from the surface. The effects of grain size on the amount of monoclinic transformation were also investigated. This study aimed to determine if the grain size of partially stabilized zirconia affects the amount of monoclinic transformation, surface roughness, and property degradation due to aging. The rejected null hypothesis is that the grain size will not affect the amount of monoclinic transformation, thus have no effect on surface roughening or property degradation. The final part of this study addresses the wear of enamel when opposing zirconia by observing how grain size and aging affected the wear rate of an enamel antagonist

  11. 1-Nitro-4-(4-nitro-phen-oxy)benzene: a second monoclinic polymorph.

    Science.gov (United States)

    Naz, Mehwish; Akhter, Zareen; McKee, Vickie; Nadeem, Arif

    2013-11-01

    In the title compound, C12H8N2O5, the aromatic rings are inclined to one another by 56.14 (7)°. The nitro groups are inclined by to the benzene rings to which they are attached by 3.86 (17) and 9.65 (15)°. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds, forming a three-dimensional structure. The title compound is a new monoclinic polymorph, crystallizing in space group P21/c. The first polymorph crystallized in space group C2/c and the mol-ecule possesses twofold rotation symmetry. Two low-temperature structures of this polymorph (150 K and 100 K, respectively) have been reported [Meciarova et al. (2004). Private Communication (refcode IXOGAD). CCDC, Cambridge, England, and Dey & Desiraju (2005). Chem. Commun. pp. 2486-2488].

  12. A monoclinic polymorph of 2-(4-nitrophenylacetic acid

    Directory of Open Access Journals (Sweden)

    Alan R. Kennedy

    2016-12-01

    Full Text Available A new monoclinic form of 4-nitrophenylacetic acid, C8H7NO4, (I, differs from the known orthorhombic form both in its molecular conformation and in its intermolecular contacts. The conformation is different as the plane of the carboxylic acid group in (I is more nearly perpendicular to the plane of the aromatic ring [dihedral angle = 86.9 (3°] than in the previous form (74.5°. Both polymorphs display hydrogen-bonded R22(8 carboxylic acid dimeric pairs, but in (I, neighbouring dimers interact through nitro–nitro N...O dipole–dipole contacts rather than the nitro–carbonyl contacts found in the orthorhombic form.

  13. Monoclinic polymorph of poly[aqua(μ4-hydrogen tartratosodium

    Directory of Open Access Journals (Sweden)

    Mohammad T. M. Al-Dajani

    2010-02-01

    Full Text Available A monoclinic polymorph of the title compound, [Na(C4H5O6(H2O]n, is reported and complements an orthorhombic form [Kubozono, Hirano, Nagasawa, Maeda & Kashino (1993. Bull. Chem. Soc. Jpn, 66, 2166–2173]. The asymmetric unit contains a hydrogen tartrate anion, an Na+ cation and a water molecule. The Na+ ion is surrounded by seven O atoms derived from one independent and three symmetry-related hydrogen tartrate anions, and a water molecule, forming a distorted pentagonal–bipyramidal geometry. Independent units are linked via a pair of intermolecular bifurcated O—H...O acceptor bonds, generating an R21(6 ring motif to form polymeric two-dimensional arrays parallel to the (100 plane. In the crystal packing, the arrays are linked by adjacent ring motifs, together with additional intermolecular O—H...O interactions, into a three-dimensional network.

  14. Understanding the Structure of Amorphous Thin Film Hafnia - Final Paper

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, Andre [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-27

    Hafnium Oxide (HfO2) amorphous thin films are being used as gate oxides in transistors because of their high dielectric constant (κ) over Silicon Dioxide. The present study looks to find the atomic structure of HfO2 thin films which hasn’t been done with the technique of this study. In this study, two HfO2 samples were studied. One sample was made with thermal atomic layer deposition (ALD) on top of a Chromium and Gold layer on a silicon wafer. The second sample was made with plasma ALD on top of a Chromium and Gold layer on a Silicon wafer. Both films were deposited at a thickness of 50nm. To obtain atomic structure information, Grazing Incidence X-ray diffraction (GIXRD) was carried out on the HfO2 samples. Because of this, absorption, footprint, polarization, and dead time corrections were applied to the scattering intensity data collected. The scattering curves displayed a difference in structure between the ALD processes. The plasma ALD sample showed the broad peak characteristic of an amorphous structure whereas the thermal ALD sample showed an amorphous structure with characteristics of crystalline materials. This appears to suggest that the thermal process results in a mostly amorphous material with crystallites within. Further, the scattering intensity data was used to calculate a pair distribution function (PDF) to show more atomic structure. The PDF showed atom distances in the plasma ALD sample had structure up to 10 Å, while the thermal ALD sample showed the same structure below 10 Å. This structure that shows up below 10 Å matches the bond distances of HfO2 published in literature. The PDF for the thermal ALD sample also showed peaks up to 20 Å, suggesting repeating atomic spacing outside the HfO2 molecule in the sample. This appears to suggest that there is some crystalline structure within the thermal ALD sample.

  15. Expectation and Locality Effects in German Verb-final Structures.

    Science.gov (United States)

    Levy, Roger P; Keller, Frank

    2013-02-01

    Probabilistic expectations and memory limitations are central factors governing the real-time comprehension of natural language, but how the two factors interact remains poorly understood. One respect in which the two factors have come into theoretical conflict is the documentation of both locality effects, in which more dependents preceding a governing verb increase processing difficulty at the verb, and anti-locality effects, in which more preceding dependents facilitate processing at the verb. However, no controlled study has previously demonstrated both locality and anti-locality effects in the same type of dependency relation within the same language. Additionally, many previous demonstrations of anti-locality effects have been potentially confounded with lexical identity, plausibility, and sentence position. Here, we provide new evidence of both locality and anti-locality effects in the same type of dependency relation in a single language-verb-final constructions in German-while controlling for lexical identity, plausibility, and sentence position. In main clauses, we find clear anti-locality effects, with the presence of a preceding dative argument facilitating processing at the final verb; in subject-extracted relative clauses with identical linear ordering of verbal dependents, we find both anti-locality and locality effects, with processing facilitated when the verb is preceded by a dative argument alone, but hindered when the verb is preceded by both the dative argument and an adjunct. These results indicate that both expectations and memory limitations need to be accounted for in any complete theory of online syntactic comprehension.

  16. THE MONOCLINIC PHASE IN PZT: NEW LIGHT ON MORPHOTROPIC PHASE BOUNDARIES

    Energy Technology Data Exchange (ETDEWEB)

    NOHEDA,B.; GONZALO,J.A.; GUO,R.; PARK,S.E.; CROSS,L.E.; COX,D.E.; SHIRANE,G.

    2000-03-09

    A summary of the work recently carried out on the morphotropic phase boundary (MPB) of PZT is presented. By means of x-ray powder diffraction on ceramic samples of excellent quality, the MPB has been successfully characterized by changing temperature in a series of closely spaced compositions. As a result, an unexpected monoclinic phase has been found to exist in between the well-known tetragonal and rhombohedral PZT phases. A detailed structural analysis, together with the investigation of the field effect in this region of compositions, have led to an important advance in understanding the mechanisms responsible for the physical properties of PZT as well as other piezoelectric materials with similar morphotropic phase boundaries.

  17. Stability of Bulk Metallic Glass Structure. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Jain, H.; Williams, D. B.

    2003-06-01

    The fundamental origins of the stability of the (Pd-Ni){sub 80}P{sub 20} bulk metallic glasses (BMGs), a prototype for a whole class of BMG formers, were explored. While much of the properties of their BMGs have been characterized, their glass-stability have not been explained in terms of the atomic and electronic structure. The local structure around all three constituent atoms was obtained, in a complementary way, using extended X-ray absorption fine structure (EXAFS), to probe the nearest neighbor environment of the metals, and extended energy loss fine structure (EXELFS), to investigate the environment around P. The occupied electronic structure was investigated using X-ray photoelectron spectroscopy (XPS). The (Pd-Ni){sub 80}P{sub 20} BMGs receive their stability from cumulative, and interrelated, effects of both atomic and electronic origin. The stability of the (Pd-Ni){sub 80}P{sub 20} BMGs can be explained in terms of the stability of Pd{sub 60}Ni{sub 20}P{sub 20} and Pd{sub 30}Ni{sub 50}P{sub 20}, glasses at the end of BMG formation. The atomic structure in these alloys is very similar to those of the binary phosphide crystals near x=0 and x=80, which are trigonal prisms of Pd or Ni atoms surrounding P atoms. Such structures are known to exist in dense, randomly-packed systems. The structure of the best glass former in this series, Pd{sub 40}Ni{sub 40}P{sub 20} is further described by a weighted average of those of Pd{sub 30}Ni{sub 50}P{sub 20} and Pd{sub 60}Ni{sub 20}P{sub 20}. Bonding states present only in the ternary alloys were found and point to a further stabilization of the system through a negative heat of mixing between Pd and Ni atoms. The Nagel and Tauc criterion, correlating a decrease in the density of states at the Fermi level with an increase in the glass stability, was consistent with greater stability of the Pd{sub x}Ni{sub 80-x}P{sub 20} glasses with respect to the binary alloys of P. A valence electron concentration of 1.8 e/a, which

  18. Structural evolution of carbon during oxidation. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Sarofim, A.F.

    1998-04-01

    The examination of the structural evolution of carbon during oxidation has proven to be of scientific interest. Early modeling work of fluidized bed combustion showed that most of the reactions of interest occurs in the micropores, and this work has concentrated on these pores. This work has concentrated on evolution of macroporosity and microporosity of carbons during kinetic controlled oxidation using SAXS, CO{sub 2} and TEM analysis. Simple studies of fluidized bed combustion of coal chars has shown that many of the events considered fragmentation events previously may in fact be {open_quotes}hidden{close_quotes} or nonaccessible porosity. This makes the study of the microporous combustion characteristics of carbon even more important. The generation of a combustion resistant grid, coupled with measurements of the SAXS and CO{sub 2} surface areas, fractal analysis and TEM. Studies has confirmed that soot particles shrink during their oxidation, as previously suspected. However, this shrinkage results in an overall change in structure. This structure becomes, on a radial basis, much more ordered near the edges, while the center itself becomes transparent to the TEM beam, implying a total lack of structure in this region. Although complex, this carbon structure is probably burning as to keep the density of the soot particles nearly the same. The TEM techniques developed for examination of soots has also been applied to Spherocarb. The Spherocarb during oxidation also increases its ordering. This ordering, by present theories, would imply that the reactivity would go. However, the reactivity goes up, implying that structure of carbon is secondary in importance to catalytic effects.

  19. Unexpected origin of magnetism in monoclinic Nb12O29 from first-principles calculations

    NARCIS (Netherlands)

    Fang, C. M.; Van Huis, M. A.; Xu, Q.; Cava, R. J.; Zandbergen, H. W.

    2015-01-01

    Nb12O29 is a 4d transition metal oxide that occurs in two forms with different symmetries, monoclinic (m) and orthorhombic (o). The monoclinic form has unusual magnetic properties; below a temperature of 12 K, it exhibits both metallic conductivity and antiferromagnetic ordering. Here, first-princip

  20. Low-temperature magnetic properties of monoclinic pyrrhotite with particular relevance to the Besnus transition

    Science.gov (United States)

    Volk, Michael W. R.; Gilder, Stuart A.; Feinberg, Joshua M.

    2016-12-01

    Monoclinic pyrrhotite (Fe7S8) owes its ferrimagnetism to an ordered array of Fe vacancies. Its magnetic properties change markedly around 30 K, in what is known as the Besnus transition. Plausible explanations for the Besnus transition are either due to changes in crystalline anisotropy from a transformation in crystal symmetry or from the establishment of a two-phase system with magnetic interaction between the two phases. To help resolve this discrepancy, we measured hysteresis loops every 5° and backfield curves every 10° in the basal plane of an oriented single crystal of monoclinic pyrrhotite at 300 K and every 2 K from 50 K through the Besnus transition until 20 K. Between 50 and 30 K, hysteresis loops possess double inflections between crystallographic a-axes and only a single inflection parallel to the a-axes. Magnetization energy calculations and relative differences of the loops show a sixfold symmetry in this temperature range. We propose that the inflections stem from magnetic axis switching, which is both field and temperature dependent, in a manner somewhat analogous to an isotropic point where magnetocrystalline constants change their sign. The Besnus transition is best characterized by changes in magnetic remanence and coercivity over a 6° temperature span (28-34 K) with a maximum rate of change at 30 K. A surprising yet puzzling finding is that the coercivity ratio becomes less than unity below the transition when fourfold symmetry arises. Because the changes in magnetic parameters are linked to the crystal structure, we conclude the Besnus transition owes its origin to a distortion of the crystallographic axes below 30 K rather than an apparition of a two-phase system. An isothermal magnetization of natural pyrrhotite cycled from room temperature to successively lower temperatures through the Besnus transition decreases 2-4 times less than equivalent grain sizes of magnetite, with less than a 10 per cent loss in remanence between 300 and 150 K

  1. A Comparative Structural and Electrochemical Study of Monoclinic Li3V2(PO4)3/C and Rhombohedral Li2.5Na0.5V2(PO4)3/C%Li3V2(PO4)3/C和Li2.5Na0.5V2(PO4)3/C的结构和电化学性能的比较研究

    Institute of Scientific and Technical Information of China (English)

    王文辉; 陈振宇; 戴长松; 纪大龙; 李佳杰; 魏杰

    2012-01-01

    A lithium-ion battery cathode material,Li2.5Na0.5V2(PO4)3/C,was prepared by the sol-gel method and characterized by X-ray diffraction (XRD),cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS).As a control,Li3V2(PO4)3/C (LVP/C) was also prepared and studied.The effect of sodium-ion doping on the structure and electrochemical properties was studied.The XRD pattern of Li2.5Na0.5V2(PO4)3/C indicates that the monoclinic structure of Li3-xNaxV2(PO4)3 has transformed into a rhombohedral structure because of large amount of sodium-ion doping.For Li25Na0.5V2(PO4)3/C,a specific discharge capacity of 118 mAh·g-1 is achieved at a 0.5 C charge rate and 1 C discharge rate,and a 92.4% retention rate of the initial capacity is obtained after 50 cycles.Different from monoclinic LVP,there is only one discharge plateau at 3.7 V in the charge/discharge voltage profile of Li2.5Na0.5V2(PO4)3/C.%采用溶胶-凝胶法合成了锂离子正极材料Li3V2(PO4)JC(LVP/C)及Li2.5Na0.5V2(PO4)3/C,并用XRD、循环伏安及交流阻抗等方法,研究了大量Na+掺杂对材料结构和电化学性能影响.结果表明,大量钠离子的掺杂会使LVP结构由单斜向菱方转变.掺杂化合物Li2.5Na0.5V2(PO4)/C在0.5 C充电1C放电时,首次放电容量为118 mAh·g-1,50次循环后容量保持率为92.4%,并发现与单斜LVP存在多个放电平台不同,Li2.5Na0.5V2(PO4)3/C仅在3.7 V处有一个放电平台.

  2. Final Technical Report: Electronic Structure Workshop (ES13)

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shiwei [College of William and Mary, Williamsburg, VA (United States)

    2015-02-26

    The 25th Annual Workshop on Recent Developments in Electronic Structure Methods (ES2013) was successfully held at the College of William & Mary in Williamsburg VA on June 11-14, 2013. The workshop website is at http://es13.wm.edu/ , which contains updated information on the workshop and a permanent archive of the scientific contents. DOE's continued support has been instrumental to the success of the workshop.

  3. Dispersion of Love Waves in a Composite Layer Resting on Monoclinic Half-Space

    Directory of Open Access Journals (Sweden)

    Sukumar Saha

    2011-01-01

    Full Text Available Dispersion of Love waves is studied in a fibre-reinforced layer resting on monoclinic half-space. The wave velocity equation has been obtained for a fiber-reinforced layer resting on monoclinic half space. Shear wave velocity ratio curve for Love waves has been shown graphically for fibre reinforced material layer resting on various monoclinic half-spaces. In a similar way, shear wave velocity ratio curve for Love waves has been plotted for an isotropic layer resting on various monoclinic half-spaces. From these curves, it has been observed that the curves are of similar type for a fibre reinforced layer resting on monoclinic half-spaces, and the shear wave velocity ratio ranges from 1.14 to 7.19, whereas for the case isotropic layer, this range varies from 1.0 to 2.19.

  4. Final Technical Report: Investigation of Nuclear Partonic Structure

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, Henry J. [Univ. of California, Berkeley, CA (United States)

    2016-08-30

    Our research program had two primary goals during the period of this grant, to search for new and rare particles produced in high-energy nuclear collisions and to understand the internal structure of nuclear matter. We have developed electronics to pursue these goals at the Relativistic Heavy Ion Collider (RHIC) in the Solenoidal Tracker at RHIC (STAR) experiment and the AnDY experiment. Our results include discovery of the anti-hyper-triton, anti- 3Λ-barH, which opened a new branch on the chart of the nuclides, and the anti-alpha, anti- 4He, the heaviest form of anti-matter yet seen, as well as uncovering hints of gluon saturation in cold nuclear matter and observation of jets in polarized proton-proton collisions that will be used to probe orbital motion inside protons.

  5. Identification and structural analysis of ricin inhibitors. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Robertus, J.D.

    1996-12-01

    Ricin is a potent cytotoxin which has been used by governments and terrorists as a poison. The three-dimensional structure of this toxic molecule was solved by X-ray crystallography, including an atomic description of its active site. The goal of this project was to use computer searches and other molecular modeling techniques to identify an inhibitor or ricin A chain (RTA). The program CHEM-X was used to predict that pteroic acid (PTA) would bind to RTA. This was shown to be the case by kinetic assays, where PTA protected ribosomes against the action of RTA, and by X-ray crystallography. The affinity of PTA is weak, with a Ki estimated at 600 Micrometers. The pterin group of PTA was observed to make many polar interactions with RTA within the specificity site of the enzyme, and to bind more strongly than the natural substrate adenine. Further work will be required to increase the binding affinity of this class of inhibitors, and to improve their solubility if efficacious antidotes are to be designed from this lead.

  6. Inventory of vegetation structure and phenology at Kulm Wetland Management District : Inventory and Monitoring final report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Fiscal year 2012 final report for the inventory of vegetation structure and phenology at Kulm Wetland Management District. The purpose of the study was to conduct a...

  7. Final Report - Investigation of Intermittent Turbulence and Turbulent Structures in the Presence of Controlled Sheared Flows

    Energy Technology Data Exchange (ETDEWEB)

    Gilmore, Mark A. [University of New Mexico

    2013-06-27

    Final Report for grant DE-FG02-06ER54898. The dynamics and generation of intermittent plasma turbulent structures, widely known as "blobs" have been studied in the presence of sheared plasma flows in a controlled laboratory experiment.

  8. Bis[2-(hy-droxy-imino-meth-yl)phenolato]nickel(II): a second monoclinic polymorph.

    Science.gov (United States)

    Rusanova, Julia A; Buvaylo, Elena A; Rusanov, Eduard B

    2011-01-15

    The title compound, [Ni(C(7)H(6)NO(2))(2)], (I), is a second monoclinic polymorph of the compound, (II), reported by Srivastava et al. [Acta Cryst. (1967), 22, 922] and Mereiter [Private communication (2002) CCDC refcode NISALO01]. The bond lengths and angles are similar in both structures. The mol-ecule in both structures lies on a crystallographic inversion center and both have an inter-nal hydrogen bond. The title compound crystallizes in the space group P2(1)/c (Z = 2), whereas compound (II) is in the space group P2(1)/n (Z = 2) with a similar cell volume but different cell parameters. In both polymorphs, mol-ecules are arranged in the layers but in contrast to the previously published compound (II) where the dihedral angle between the layers is 86.3°, in the title polymorph the same dihedral angle is 29.4°. The structure of (I) is stabilized by strong intra-molecular O-H⋯O hydrogen bonding between the O-H group and the phenolate O atom.

  9. Crystal structure of owyheeite, Ag1.5Pb4.43Sb6.07S14

    DEFF Research Database (Denmark)

    Laufek, Frantisek; Pazout, Richard; Makovicky, Emil

    2007-01-01

    The crystal structure of owyheeite, a natural Ag-Pb-Sb sulphosalt from hydrothermal veins at Kutná Hora in central Bohemia, Czech Republic has been refined from powder X-ray synchrotron data, with a final Rwp = 4.1 %. The symmetry is monoclinic, space group P21/c, with a = 4.1035(1), b = 27...

  10. Observation of spin glass behavior in monoclinic Li{sub 0.33}MnO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Bie, Xiaofei; Wei, Yingjin; Liu, Lina [Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012 (China); Nikolowski, Kristian; Ehrenberg, Helmut [Institute for Applied Materials (IAM), Karlsruhe Institute of Technology (KIT), D-76344 Eggenstein-Leopoldshafen (Germany); Chen, Hong [College of Physics, Beihua University, Jilin 132013 (China); Wang, Chunzhong; Chen, Gang [Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012 (China); Du, Fei, E-mail: dufei@jlu.edu.cn [Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012 (China)

    2013-02-25

    Highlights: Black-Right-Pointing-Pointer The structure of Li{sub 0.33}MnO{sub 2} has been refined with monoclinic phase (space group C2/m). Black-Right-Pointing-Pointer Spin glass has been confirmed by analyzing dc, ac, and time-dependence remanence. Black-Right-Pointing-Pointer Geometrical frustration combined random competition was suggested to be the main cause for spin glass formation. Black-Right-Pointing-Pointer In order to distinguish the spin glass from the superparamagnetism, ac susceptibility under different frequencies is studied. - Abstract: The structure and magnetic properties of Li{sub 0.33}MnO{sub 2} were studied by X-ray diffraction, dc and ac susceptibilities. Li{sub 0.33}MnO{sub 2} belongs to the monoclinic structure with two different Mn sites. The irreversibility and spin freezing behaviors are observed in the dc magnetization curves. The peaks of ac susceptibility display the dependences on the frequency. Both the magnetic relaxation effect and the corresponding analysis confirm a spin glass (SG) transition at low temperature. By evaluating the geometrical frustration parameter, we suggest the spin glass in Li{sub 0.33}MnO{sub 2} originate from the frustration effect combined with the competition among the Mn{sup 3+/4+}-O{sup 2-}-Mn{sup 3+/4+} exchange interaction.

  11. The INTELLIGENT RuleTutor: A Structured Approach to Intelligent Tutoring. Final Report.

    Science.gov (United States)

    Scandura, Alice B.

    This final report describes a general purpose system for developing intelligent tutors based on the Structural Learning Theory. The report opens with a discussion of the rules and related constructs that underlie cognitive constructs in all structural learning theories. The remainder of the text provides: (1) an introduction to the Structural…

  12. Elastic and vibrational properties of monoclinic HfO2 from first-principles study

    Science.gov (United States)

    Wu, Rui; Zhou, Bo; Li, Qian; Jiang, ZhenYi; Wang, WenBo; Ma, WenYan; Zhang, XiaoDong

    2012-03-01

    The elastic and vibrational properties of crystalline monoclinic HfO2 have been investigated using density functional perturbation theory. Using the Voigt and Reuss theory, we estimate the bulk, shear and Young's modulus for polycrystalline HfO2, which agree very well with the available experimental and theoretical data. Additionally, we present a systematic analysis of the elastic properties of HfO2 polymorphs and find the trends in the elastic parameters for the HfO2 structures are consistent with those for the ZrO2 structures. The choice of exchange-correlation functional has an important effect on the results of elastic and vibrational properties. The utilization of Hartwigzen-Goedecker-Hutter type functional is a great improvement on calculation of the zone-centre phonon frequencies, and shows the root-mean-square absolute deviation of 7 cm-1 with experiments. A rigorous assignment of all the Raman modes is achieved by combining symmetry analysis with the first-principles calculations, which helps us to identify the main peak and some other features of Raman spectra. Furthermore, the Raman spectrum of HfO2 powder has been simulated for the first time, providing a theoretical benchmark for the interpretation of the unresolved problems in experimental studies.

  13. Structural and Parametric Models of the Załęcze and Żuchlów Gas Field Region, Fore-Sudetic Monocline, Poland – An Example of a General Static Modeling Workflow in Mature Petroleum Areas for CCS, EGR or EOR Purposes

    Directory of Open Access Journals (Sweden)

    Papiernik Bartosz

    2015-04-01

    Full Text Available Załęcze and Żuchlów are strongly depleted natural gas fields in aeolian sandstones of the Rotliegend, located in the central part of the Fore-Sudetic Monocline. A set of three static 3D models was generated to check the possibility of CO2 injection for Enhanced Gas Recovery (EGR and to check the safety of storage by means of geomechanical modeling: one regional model (ZZA and two local models – the first for Załęcze (ZA gas field and the second for Żuchlów (ZU gas field. The regional model is composed of 12 stratigraphic complexes (zones from the base of the Rotliegend to the ground surface. The local models comprise only the three lowermost complexes: fluvial deposits of the Rotliegend, aeolian sandstones of the Rotliegend (Reservoir I and basal Zechstein limestone, Ca1. The key elements of the modeling procedure include: Quality Control (QC of the data, interpretation of missing parameters necessary for static modeling and their integration within a geomodel. The processing workflow was elaborated to produce convergent regional and local models. The regional static model is a framework for a regional geomechanical model. The local models are the basis for dynamic simulations and local geomechanical modeling. The presented workflow could be used with some changes for geomodeling of many mature gas and oil fields.

  14. Final structural and mechanical evaluation of the W7-X magnet support system

    Energy Technology Data Exchange (ETDEWEB)

    Jaksic, N. E-mail: nikola.jaksic@ipp.mpg.de; Simon-Weidner, J.; Sapper, J

    2001-11-01

    The plasma fusion experiment WENDELSTEIN7-X (W7-X) of the stellarator family, which was developed at the Max-Planck-Institute for Plasmaphysik, is in the state of the final detail design. W7-X is planned for first operation in 2006. Currently the main components (coils, magnet support structure, vacuum vessel, etc) are ordered to be manufactured. This paper gives a summarisation of the development of the magnet support structure during the last 10 years. Of course, the final design and its structural analyses are the main topic of the discussion. Finally, it is tried to summarize the cognition won until now and based on this knowledge to give the recommendations for future activities.

  15. Monoclinic high-pressure polymorph of AlOOH predicted from first principles

    Science.gov (United States)

    Zhong, Xin; Hermann, Andreas; Wang, Yanchao; Ma, Yanming

    2016-12-01

    Aluminum oxide hydroxide, AlOOH, is a prototypical hydrous mineral in the geonomy. The study of the high-pressure phase evolution of AlOOH is of fundamental importance in helping to understand the role of hydrous minerals in the water storage and transport in Earth, as in other planets. Here, we have systematically investigated the high-pressure phase diagram of AlOOH up to 550 GPa using the efficient crystal structure analysis by particle swarm optimization (CALYPSO) algorithm in conjunction with first principles calculations. We predict a peculiar monoclinic phase (space group P 21/c , 16 atoms/cell, Z =4 ) as the most stable phase for AlOOH above 340 GPa. The occurrence of this new phase results in the breakup of symmetric linear O-H-O hydrogen bonds into asymmetric, bent O-H-O linkages and in sevenfold coordinated metal cations. The new P 21/c phase turns out to be a universal high-pressure phase in group 13 oxide hydroxides, and stable for both compressed GaOOH and InOOH. The formation of the new phase in all compounds is favored by volume reduction due to denser packing.

  16. Mild oxide-hydrothermal synthesis of different aspect ratios of monoclinic BiVO{sub 4} nanorods tuned by temperature

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Fengqiang; Wu, Qingsheng; Ma, Jie; Chen, Yijun [Department of Chemistry, Tongji University, Shanghai (China)

    2009-01-15

    The monoclinic scheelite BiVO{sub 4} nanocrystals were easily prepared via an oxide-hydrothermal synthesis (OHS) method directly utilizing bulk-phase materials of V{sub 2}O{sub 5} and Bi{sub 2}O{sub 3} as precursor. In the presence of PEG 4000, the reactions were performed in the mild temperature range from 130 C to 200 C. The products were characterized with FTIR, XRD, TEM and UV-vis DRS. These data clearly demonstrated that monoclinic scheelite structure BiVO{sub 4} could be synthesized by the feasible OHS route. The aspect ratios of nanorods were increased with the synthesized temperature. The as-prepared BiVO{sub 4} showed high photocatalytic activity, which was demonstrated by degradation of methylene blue (MB) solution under visible-light irradiation ({lambda}>420 nm). A growth mechanism of bismuth vanadate was proposed. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. A monoclinic polymorph of 1,2-bis[(1-methyl-1H-tetrazol-5-ylsulfanyl]ethane (BMTTE

    Directory of Open Access Journals (Sweden)

    Saray Argibay-Otero

    2017-10-01

    Full Text Available The synthesis and crystal structure of a monoclinic (P21/c polymorph of the title compound, C6H10S2N8, are reported. The molecule has pseudo-twofold rotational symmetry, with the tetrazole rings being inclined to one another by 5.50 (6°. In the crystal, molecules are linked by C—H...N hydrogen bonds, forming chains propagating along [101] and enclosing R22(20 ring motifs. The chains are linked by offset π–π interactions involving the tetrazole rings [intercentroid distances vary from 3.3567 (7 to 3.4227 (7 Å], forming layers parallel to the ac plane. The crystal structure of the triclinic polymorph (P\\overline{1} has been described previously [Li et al. (2011. Acta Cryst. E67, o1669].

  18. Electron Distributions in Hexagonal Selenium and Tellurium and Monoclinic Selenium with Dilute Impurities and Associated Nuclear Quadrupole Interactions*.

    Science.gov (United States)

    Maharjan, N. B.; Paudyal, D. D.; Mishra, D. R.; Byahut, S.; Aryal, M. M.; Cho, Hwa-Suck; Scheicher, R. H.; Chow, Lee; Jeong, Junho; Das, T. P.

    2006-03-01

    The electron structures of Selenium chains and rings with Te impurities in hexagonal and monoclinic structures respectively and Se impurities in Te chains in hexagonal lattice have been studied using Hartree-Fock cluster model including many-body effects, including lattice relaxation effects. The calculated electronic wave-functions are utilized to obtain ^77Se and ^125Te nuclear quadrupole coupling constants e^2qQ and asymmetry parameters η and compared with available experimental data from Mossbauer and perturbed angular correlation measurements. From our results, the expected nature of nuclear quadrupole interactions associated with Sb impurities will be discussed. *Supported by NSF US-Nepal Program and UGC Nepal **Also at UCF, Orlando

  19. A second monoclinic polymorph of 2-[2-(4-methoxyphenylhydrazinylidene]-1,3-diphenylpropane-1,3-dione

    Directory of Open Access Journals (Sweden)

    Carlos Bustos

    2011-07-01

    Full Text Available The title compound, C22H18N2O3 is the second monoclinic polymorph (P21/c of the compound, the first being reported in space group P21 [Bertolasi et al. (1993. J. Chem. Soc. Perkin Trans. 2, pp. 2223–2228]. In the molecular structure of the title compound, the interplanar angle between the benzoyl units is 80.04 (5°, while the corresponding angles between the phenylhydrazinylidene and benzoyl groups are 36.11 (5 and 55.77 (2°. A strong resonance-assisted intramolecular N—H...O hydrogen bond is found. In the crystal, the entire supramolecular structure is constructed by weak intermolecular C—H...O interactions and an inter-ring π–π interaction [centroid–centroid distance = 3.6088 (8 Å].

  20. Smart Intelligent Aircraft Structures (SARISTU) : Proceedings of the Final Project Conference

    CERN Document Server

    Papadopoulos, Michael

    2016-01-01

    The book includes the research papers presented in the final conference of the EU funded SARISTU (Smart Intelligent Aircraft Structures) project, held at Moscow, Russia between 19-21 of May 2015. The SARISTU project, which was launched in September 2011, developed and tested a variety of individual applications as well as their combinations. With a strong focus on actual physical integration and subsequent material and structural testing, SARISTU has been responsible for important progress on the route to industrialization of structure integrated functionalities such as Conformal Morphing, Structural Health Monitoring and Nanocomposites. The gap- and edge-free deformation of aerodynamic surfaces known as conformal morphing has gained previously unrealized capabilities such as inherent de-icing, erosion protection and lightning strike protection, while at the same time the technological risk has been greatly reduced. Individual structural health monitoring techniques can now be applied at the part-manufacturin...

  1. Photocatalytic and photoelectrochemical water oxidation over metal-doped monoclinic BiVO(4) photoanodes.

    Science.gov (United States)

    Parmar, Kanak Pal Singh; Kang, Hyun Joon; Bist, Amita; Dua, Piyush; Jang, Jum Suk; Lee, Jae Sung

    2012-10-01

    The visible-light-induced water oxidation ability of metal-ion-doped BiVO(4) was investigated and of 12 metal ion dopants tested, only W and Mo dramatically enhanced the water photo-oxidation activity of bare BiVO(4); Mo had the highest improvement by a factor of about six. Thus, BiVO(4) and W- or Mo-doped (2 atom %) BiVO(4) photoanodes about 1 μm thick were fabricated onto transparent conducting substrate by a metal-organic decomposition/spin-coating method. Under simulated one sun (air mass 1.5G, 100 mW cm(-2)) and at 1.23 V versus a reversible hydrogen electrode, the highest photocurrent density (J(PH)) of about 2.38 mA cm(-2) was achieved for Mo doping followed by W doping (J(PH) ≈ 1.98 mA cm(-2)), whereas undoped BiVO(4) gave a J(PH) value of about 0.42 mA cm(-2). The photoelectrochemical water oxidation activity of W- and Mo-doped BiVO(4) photoanodes corresponded to the incident photon to current conversion efficiency of about 35 and 40 % respectively. Electrochemical impedance spectroscopy and Mott-Schottky analysis indicated a positive flat band shift of about 30 mV, a carrier concentration 1.6-2 times higher, and a charge-transfer resistance reduced by 3-4-fold for W- or Mo-doped BiVO(4) relative to undoped BiVO(4). Electronic structure calculations revealed that both W and Mo were shallow donors and Mo doping generated superior conductivity to W doping. The photo-oxidation activity of water on BiVO(4) photoanodes (undopedphotocatalytic and photoelectrochemical water oxidation activity of monoclinic BiVO(4) by drastically reducing its charge-transfer resistance and thereby minimizing photoexcited electron-hole pair recombination.

  2. Final design of the generic upper port plug structure for ITER diagnostic systems

    Energy Technology Data Exchange (ETDEWEB)

    Pak, Sunil, E-mail: paksunil@nfri.re.kr [National Fusion Research Institute, Daejeon (Korea, Republic of); Feder, Russell [Princeton Plasma Physics Laboratory, Princeton, NJ (United States); Giacomin, Thibaud; Guirao, Julio; Iglesias, Silvia; Josseaume, Fabien [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Kalish, Michael; Loesser, Douglas [Princeton Plasma Physics Laboratory, Princeton, NJ (United States); Maquet, Philippe [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Ordieres, Javier; Panizo, Marcos [NATEC, Ingenieros, Gijón (Spain); Pitcher, Spencer; Portalès, Mickael [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Proust, Maxime [CEA, Cadarache, St. Paul-lez-Durance (France); Ronden, Dennis [FOM Institute DIFFER, Nieuwegein (Netherlands); Serikov, Arkady [Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany); Suarez, Alejandro [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Tanchuk, Victor [NIIEFA, St.-Petersburg (Russian Federation); Udintsev, Victor; Vacas, Christian [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); and others

    2016-01-15

    The generic upper port plug (GUPP) structure in ITER is a 6 m long metal box which deploys diagnostic components into the vacuum vessel. This structure is commonly used for all the diagnostic upper ports. The final design of the GUPP structure, which has successfully passed the final design review in 2013, is described here. The diagnostic port plug is cantilevered to the vacuum vessel with a heavy payload at the front, so called the diagnostic first wall (DFW) and the diagnostic shield module (DSM). Most of electromagnetic (EM) load (∼80%) occurs in DFW/DSM. Therefore, the mounting design to transfer the EM load from DFW/DSM to the GUPP structure is challenging, which should also comply with thermal expansion and tolerance for assembly and manufacturing. Another key design parameter to be considered is the gap between the port plug and the vacuum vessel port. The gap should be large enough to accommodate the remote handling of the heavy port plug (max. 25 t), the structural deflection due to external loads and machine assembly tolerance. At the same time, the gap should be minimized to stop the neutron streaming according to the ALARA (as low as reasonably achievable) principle. With these design constraints, the GUPP structure should also provide space for diagnostic integration as much as possible. This requirement has led to the single wall structure having the gun-drilled water channels inside the structure. Furthermore, intensive efforts have been made on the manufacturing study including material selection, manufacturing codes and French regulation related to nuclear equipment and safety. All these main design and manufacturing aspects are discussed in this paper, including requirements, interfaces, loads and structural assessment and maintenance.

  3. Synthesis and Dielectric Studies of Monoclinic Nanosized Zirconia

    OpenAIRE

    I. Flavia Princess Nesamani; V. Lakshmi Prabha; Aswathy Paul; Nirmal, D.

    2014-01-01

    Zirconium dioxide is a prospective high-κ material that can replace silicon dioxide. Zirconium dioxide nanoparticle has been synthesized using sol-gel process at room temperature. The structural and morphological characterization of the nanoscaled zirconium dioxide is done using FTIR, SEM, X-ray diffraction, and TEM. The particle size of the synthesized ZrO2 is observed in the range of 50–80 nm with an average crystallite size of 2–10 nm. The results are compared with commercial coarse zircon...

  4. Microstructure, bioactivity and osteoblast behavior of monoclinic zirconia coating with nanostructured surface.

    Science.gov (United States)

    Wang, Guocheng; Meng, Fanhao; Ding, Chuanxian; Chu, Paul K; Liu, Xuanyong

    2010-03-01

    A monoclinic zirconia coating with a nanostructural surface was prepared on the Ti-6Al-4V substrate by an atmospheric plasma-spraying technique, and its microstructure and composition, as well as mechanical and biological properties, were investigated to explore potential application as a bioactive coating on bone implants. X-ray diffraction, transmission electron microscopy, scanning electron microscopy and Raman spectroscopy revealed that the zirconia coating was composed of monoclinic zirconia which was stable at low temperature, and its surface consists of nano-size grains 30-50 nm in size. The bond strength between the coating and the Ti-6Al-4V substrate was 48.4 + or - 6.1 MPa, which is higher than that of plasma-sprayed HA coatings. Hydrothermal experiments indicated that the coating was stable in a water environment and the phase composition and Vickers hardness were independent of the hydrothermal treatment time. Bone-like apatite is observed to precipitate on the surface of the coating after soaking in simulated body fluid for 6 days, indicating excellent bioactivity in vitro. The nanostructured surface composed of monoclinic zirconia is believed to be crucial to its bioactivity. Morphological observation and the cell proliferation test demonstrated that osteoblast-like MG63 cells could attach to, adhere to and proliferate well on the surface of the monoclinic zirconia coating, suggesting possible applications in hard tissue replacements.

  5. Efficient channel waveguide lasers in monoclinic double tungstates: towards further integration with on-chip mirrors

    NARCIS (Netherlands)

    van Dalfsen, Koop; van Wolferen, Hendricus A.G.M.; Dijkstra, Mindert; Aravazhi, S.; Bernhardi, Edward; García Blanco, Sonia Maria; Pollnau, Markus

    2012-01-01

    By varying the thulium concentration in the range of 1.5 – 8.0 at.% in thulium- gadolinium-lutetium-yttrium-co-doped monoclinic double tungstate channel waveguides, a maximum laser slope efficiency of 70% with respect to the absorbed pump power was obtained. Further integration of these channel

  6. Weakly faceted cellular patterns versus growth-induced plastic deformation in thin-sample directional solidification of monoclinic biphenyl.

    Science.gov (United States)

    Börzsönyi, Tamás; Akamatsu, Silvère; Faivre, Gabriel

    2009-11-01

    We present an experimental study of thin-sample directional solidification (T-DS) in impure biphenyl. The platelike growth shape of the monoclinic biphenyl crystals includes two low-mobility (001) facets and four high-mobility {110} facets. Upon T-DS, biphenyl plates oriented with (001) facets parallel to the sample plane can exhibit either a strong growth-induced plastic deformation (GID), or deformation-free weakly faceted (WF) growth patterns. We determine the respective conditions of appearance of these phenomena. GID is shown to be a long-range thermal-stress effect, which disappears when the growth front has a cellular structure. An early triggering of the cellular instability allowed us to avoid GID and study the dynamics of WF patterns as a function of the orientation of the crystal.

  7. Monoclinic β-Li2TiO3: Neutron diffraction study and estimation of Li diffusion pathways

    Science.gov (United States)

    Monchak, M.; Dolotko, O.; Mühlbauer, M. J.; Baran, V.; Senyshyn, A.; Ehrenberg, H.

    2016-11-01

    A neutron powder diffraction study on lithium titanate Li2TiO3 was performed at low temperatures. The monoclinic β-phase has been found to be stable over the whole investigated range of temperatures (4 K-300 K). A smooth and nonlinear increase of the lattice parameters has been observed upon heating and correlated to the behavior of interatomic distances. Lithium diffusion pathways in Li2TiO3 were estimated theoretically on the basis of the obtained structural data using bond-valence modeling. Experimentally diffusion pathways were evaluated by analysis of the negative nuclear scattering densities at 1073 K, which were reconstructed using a maximum entropy method. Although the bond-valence mismatch map indicated a possible Li diffusion either in ab plane or along c direction, analysis of the experimental data revealed that Li migration is thermodynamically less feasible in latter case.

  8. Monoclinic BiVO{sub 4} micro-/nanostructures: Microwave and ultrasonic wave combined synthesis and their visible-light photocatalytic activities

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yafang; Li, Guangfang; Yang, Xiaohui; Yang, Hao; Lu, Zhong [Key Laboratory for Green Chemical Process of Ministry of Education and Hubei Novel Reactor and Green Chemical Technology Key Laboratory, Wuhan Institute of Technology, Xiongchu Avenue, Wuhan 430073 (China); Chen, Rong, E-mail: rchenhku@hotmail.com [Key Laboratory for Green Chemical Process of Ministry of Education and Hubei Novel Reactor and Green Chemical Technology Key Laboratory, Wuhan Institute of Technology, Xiongchu Avenue, Wuhan 430073 (China); Engineering Research Center of Nano-Geomaterials of Ministry of Education, China University of Geosciences, Lumo Road, Wuhan 430074 (China)

    2013-02-25

    Graphical abstract: Monoclinic BiVO{sub 4} with different sizes and morphologies were synthesized by a facile microwave and ultrasonic wave combined technique for the first time and exhibited different optical properties and visible-light-driven photocatalytic efficiency. Highlights: Black-Right-Pointing-Pointer BiVO{sub 4} nanostructures were prepared by microwave and ultrasonic wave combined method. Black-Right-Pointing-Pointer BiVO{sub 4} nanostructures could be modulated by varying the solvent and pH value. Black-Right-Pointing-Pointer Different BiVO{sub 4} nanostructures exhibited different photocatalytic activities. Black-Right-Pointing-Pointer The photocatalytic performance was influenced by the band gap, phase and size. - Abstract: Monoclinic bismuth vanadate (m-BiVO{sub 4}) micro-/nanostructures with different sizes and morphologies were successfully prepared via a facile and rapid microwave and ultrasonic wave combined technique. The obtained BiVO{sub 4} products were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and UV-vis diffuse reflection spectroscopy (DRS). It was found that the solvent and pH value had a significant influence on morphology, size and crystalline structure of the product. Nut-like, potato-like and broccoli-like monoclinic BiVO{sub 4} were fabricated in different solvents. The crystal phase could be modulated by varying the pH value of reaction system. The photocatalytic activities of the products were also evaluated by the degradation of Rhodamine B (RhB) under visible light irradiation. The result revealed that the photocatalytic activities of BiVO{sub 4} nanostructures were closely related to the crystalline phase, band gap and particle size. Monoclinic BiVO{sub 4} nanoparticles with small crystal size and large band gap exhibited remarkable photocatalytic performance.

  9. Synthesis and Dielectric Studies of Monoclinic Nanosized Zirconia

    Directory of Open Access Journals (Sweden)

    I. Flavia Princess Nesamani

    2014-01-01

    Full Text Available Zirconium dioxide is a prospective high-κ material that can replace silicon dioxide. Zirconium dioxide nanoparticle has been synthesized using sol-gel process at room temperature. The structural and morphological characterization of the nanoscaled zirconium dioxide is done using FTIR, SEM, X-ray diffraction, and TEM. The particle size of the synthesized ZrO2 is observed in the range of 50–80 nm with an average crystallite size of 2–10 nm. The results are compared with commercial coarse zirconia which showed a particle size in the range of 900 nm–2.13 µm and crystallite size of 5.3 nm–20 nm. It is expected that both nanoscaling and the high dielectric constant of ZrO2 would be useful in replacing the low-κ SiO2 dielectric with high-κ ZrO2 for CMOS fabrication technology. The synthesized ZrO2 is subjected to impedance analysis and it exhibited a dielectric constant of 25 to find its application in short channel devices like multiple gate FinFETS and as a suitable alternative for the conventional gate oxide dielectric SiO2 with dielectric value of 3.9, which cannot survive the challenge of an end of oxide thickness ≤ 1 nm.

  10. Reflection of and SV waves at the free surface of a monoclinic elastic half-space

    Indian Academy of Sciences (India)

    Sarva Jit Singh; Sandhya Khurana

    2002-12-01

    The propagation of plane waves in an anisotropic elastic medium possessing monoclinic symmetry is discussed. The expressions for the phase velocity of qP and qSV waves propagating in the plane of elastic symmetry are obtained in terms of the direction cosines of the propagation vector. It is shown that, in general, qP waves are not longitudinal and qSV waves are not transverse. Pure longitudinal and pure transverse waves can propagate only in certain specific directions. Closed-form expressions for the reflection coefficients of qP and qSV waves incident at the free surface of a homogeneous monoclinic elastic half-space are obtained. These expressions are used for studying numerically the variation of the reflection coefficients with the angle of incidence. The present analysis corrects some fundamental errors appearing in recent papers on the subject.

  11. Crystalline and magnetic ordering in the monoclinic phase of the layered perovskite PAMC

    DEFF Research Database (Denmark)

    Harris, P.; Lebech, B.; Achiwa, N.

    1994-01-01

    of 1/3b*, and below 39 K PAMC is an antiferromagnet with a small ferromagnetic component. The temperature dependence of the monoclinic angle alpha depends on the mosaicity of the crystal which increases with the number of 'cooling cycles'. The satellite reflections do not have any contribution from...... the magnetic ordering, but their intensity has abrupt changes that coincide with changes in either the nuclear or the magnetic ordering parameter. Magnetoelastic effects seem to influence the ordering of the crystal....

  12. Changes in mobility of plastic crystal ethanol during its transformation into the monoclinic crystal state

    Energy Technology Data Exchange (ETDEWEB)

    Sanz, Alejandro, E-mail: alejandro.sanz@csic.es; Nogales, Aurora; Ezquerra, Tiberio A. [Instituto de Estructura de la Materia, IEM-CSIC, Serrano 121, 28006 Madrid (Spain); Puente-Orench, Inés [Institut Laue-Langevin, BP 156, 38042 Grenoble Cedex 9 (France); Instituto de Ciencia de Materiales de Aragón, ICMA-CSIC, Pedro Cerbuna 12, 50009 Zaragoza (Spain); Jiménez-Ruiz, Mónica [Institut Laue-Langevin, BP 156, 38042 Grenoble Cedex 9 (France)

    2014-02-07

    Transformation of deuterated ethanol from the plastic crystal phase into the monoclinic one is investigated by means of a singular setup combining simultaneously dielectric spectroscopy with neutron diffraction. We postulate that a dynamic transition from plastic crystal to supercooled liquid-like configuration through a deep reorganization of the hydrogen-bonding network must take place as a previous step of the crystallization process. Once these precursor regions are formed, subsequent crystalline nucleation and growth develop with time.

  13. Lifting the geometric frustration through a monoclinic distortion in “114” YBaFe{sub 4}O{sub 7.0}: Magnetism and transport

    Energy Technology Data Exchange (ETDEWEB)

    Duffort, V.; Sarkar, T. [CRISMAT, CNRS-ENSICAEN, 6 Bd Marechal Juin, 14050 Caen (France); Caignaert, V., E-mail: vincent.caignaert@ensicaen.fr [CRISMAT, CNRS-ENSICAEN, 6 Bd Marechal Juin, 14050 Caen (France); Pralong, V.; Raveau, B. [CRISMAT, CNRS-ENSICAEN, 6 Bd Marechal Juin, 14050 Caen (France); Avdeev, M. [Bragg Institute, Australian Nuclear Science and Technology Organization, PMB 1, Menai, NSW 2234 (Australia); Cervellino, A. [Paul Scherrer Institute, Swiss Light Source, CH-5232 Villigen (Switzerland); Waerenborgh, J.C.; Tsipis, E.V. [UCQR, IST/ITN, Instituto Superior Técnico, Universidade Técnica de Lisboa, CFMC-UL, 2686-953 Sacavém (Portugal)

    2013-09-15

    The possibility to lift the geometric frustration in the “114” stoichiomeric tetragonal oxide YBaFe{sub 4}O{sub 7.0} by decreasing the temperature has been investigated using neutron and synchrotron powder diffraction techniques. Besides the structural transition from tetragonal to monoclinic symmetry that appears at T{sub S}=180 K, a magnetic transition is observed below T{sub N}=95 K. The latter corresponds to a lifting of the 3D geometric frustration toward an antiferromagnetic long range ordering, never observed to date in a cubic based “114’” oxide. The magnetic structure, characterized by the propagation vector k{sub 1}=(0,0,½), shows that one iron Fe2 exhibits a larger magnetic moment than the three others, suggesting a possible charge ordering according to the formula YBaFe{sup 3+}Fe{sub 3}{sup 2+}O{sub 7.0}. The magnetic M(T) and χ′(T) curves, in agreement with neutron data, confirm the structural and magnetic transitions and evidence the coexistence of residual magnetic frustration. Moreover, the transport measurements show a resistive transition from a thermally activated conduction mechanism to a variable range hopping mechanism at T{sub S}=180 K, with a significant increase of the dependence of the resistivity vs. temperature. Mössbauer spectroscopy clearly evidences a change in the electronic configuration of the iron framework at the structural transition as well as coexistence of several oxidation states. The role of barium underbonding in these transitions is discussed. - Graphical abstract: Atomic displacements at the tetragonal-monoclinic transition in YBaFe{sub 4}O{sub 7}. Display Omitted - Highlights: • The structural and magnetic phase transitions of YBaFe{sub 4}O{sub 7} were studied below room temperature. • The tetragonal to monoclinic transition, characterized by NPD and SXRD, was studied using mode crystallography approach. • Monoclinic distortion allows the lifting of the geometrical frustration on the iron sublattice

  14. Formation energies of intrinsic point defects in monoclinic VO2 studied by first-principles calculations

    Science.gov (United States)

    Cui, Yuanyuan; Liu, Bin; Chen, Lanli; Luo, Hongjie; Gao, Yanfeng

    2016-10-01

    VO2 is an attractive candidate for intelligent windows and thermal sensors. There are challenges for developing VO2-based devices, since the properties of monoclinic VO2 are very sensitive to its intrinsic point defects. In this work, the formation energies of the intrinsic point defects in monoclinic VO2 were studied through the first-principles calculations. Vacancies, interstitials, as well as antisites at various charge states were taken into consideration, and the finite-size supercell correction scheme was adopted as the charge correction scheme. Our calculation results show that the oxygen interstitial and oxygen vacancy are the most abundant intrinsic defects in the oxygen rich and oxygen deficient condition, respectively, indicating a consistency with the experimental results. The calculation results suggest that the oxygen interstitial or oxygen vacancy is correlated with the charge localization, which can introduce holes or electrons as free carriers and subsequently narrow the band gap of monoclinic VO2. These calculations and interpretations concerning the intrinsic point defects would be helpful for developing VO2-based devices through defect modifications.

  15. Evaluation of physicochemical properties, and antimicrobial efficacy of monoclinic sulfur-nanocolloid

    Energy Technology Data Exchange (ETDEWEB)

    Roy Choudhury, Samrat, E-mail: samratroychoudhury@gmail.com [Indian Statistical Institute, Biological Sciences Division (India); Mandal, Amrita; Chakravorty, Dipankar [Indian Association for the Cultivation of Science (India); Gopal, Madhuban [Indian Agricultural Research Institute, Divisions of Agricultural Chemicals (India); Goswami, Arunava [Indian Statistical Institute, Biological Sciences Division (India)

    2013-04-15

    Stable nanocolloids of monoclinic sulfur ({beta}-SNPs) were prepared through 'water-in-oil microemulsion technique' at room temperature after suitable modifications of the surface. The morphology (rod shaped; {approx}50 nm in diameter) and allotropic nature (monoclinic) of the SNPs were investigated with Transmission Electron Microscopy and X-ray Diffraction technique. The surface modification, colloidal stability, and surface topology of {beta}-SNPs were evaluated with Fourier Transform Infrared Spectroscopy, zeta potential analysis, and Atomic Force Microscopy. Thermal decomposition pattern of these nanosized particles was determined by Thermo Gravimetric Analysis (TGA). {beta}-SNPs-colloids expressed excellent antimicrobial activities against a series of fungal and bacterial isolates with prominent deformities at their surface. In contrast, insignificant cytotoxicity was achieved against the human derived hepatoma (HepG2) cell line upon treatment with {beta}-SNPs. A simultaneous study was performed to determine the stock concentration of {beta}-SNP-colloids using a novel high phase liquid chromatographic method. Cumulative results of this study hence, elucidate the stabilization of nanosized monoclinic sulfur at room temperature and their potential antimicrobial efficacy over micron-sized sulfur.

  16. Varying the counter ion changes the kinetics, but not the final structure of colloidal gels.

    Science.gov (United States)

    Zhang, Li; Mikhailovskaya, Alesya; Constantin, Doru; Foffi, Giuseppe; Tavacoli, Joseph; Schmitt, Julien; Muller, François; Rochas, Cyrille; Wang, Nan; Langevin, Dominique; Salonen, Anniina

    2016-02-01

    We show that, while the gelation of colloidal silica proceeds much faster in the presence of added KCl than NaCl, the final gels are very similar in structure and properties. We have studied the gelation process by visual inspection and by small angle X-ray scattering for a range of salt and silica particle concentrations. The characteristic times of the early aggregation process and the formation of a stress-bearing structure with both salts are shown to collapse onto master curves with single multiplicative constants, linked to the stability ratio of the colloidal suspensions. The influence of the salt type and concentration is confirmed to be mainly kinetic, as the static structure factors and viscoelastic moduli of the gels are shown to be equivalent at normalized times. While there is strong variation in the kinetics, the structure and properties of the gel at long-times are shown to be mainly controlled by the concentration of particles, and hardly influenced by the type or the concentration of salt. This suggests that the differences between gels generated by different salts are only transient in time.

  17. Cubic-to-monoclinic phase transition during the epitaxial growth of crystalline Gd2O3 films on Ge(001) substrates

    Science.gov (United States)

    Molle, Alessandro; Wiemer, Claudia; Bhuiyan, Md. Nurul Kabir; Tallarida, Grazia; Fanciulli, Marco; Pavia, Giuseppe

    2007-05-01

    Thin crystalline films of Gd2O3 are grown on an atomically flat Ge(001) surface by molecular beam epitaxy and are characterized in situ by reflection high energy electron diffraction and x-ray photoelectron spectroscopy, and ex situ by x-ray diffraction (XRD), atomic force microscopy (AFM), and transmission electron microscopy. The first stage of the growth corresponds to a cubic (110) structure, with two equiprobable, 90° rotated, in-plane domains. Increasing the thickness of the films, a phase transition from cubic (110) to monoclinic (100) oriented crystallites is observed which keeps the in-plane domain rotation, as evidenced by XRD and AFM.

  18. Coordinate-Invariant Lyddane-Sachs-Teller Relationship for Polar Vibrations in Materials with Monoclinic and Triclinic Crystal Systems.

    Science.gov (United States)

    Schubert, Mathias

    2016-11-18

    A coordinate-invariant generalization of the Lyddane-Sachs-Teller relation is presented for polar vibrations in materials with monoclinic and triclinic crystal systems. The generalization is derived from an eigendielectric displacement vector summation approach, which is equivalent to the microscopic Born-Huang description of polar lattice vibrations in the harmonic approximation. An expression for a general oscillator strength is also described for materials with monoclinic and triclinic crystal systems. A generalized factorized form of the dielectric response characteristic for monoclinic and triclinic materials is proposed. The generalized Lyddane-Sachs-Teller relation is found valid for monoclinic β-Ga_{2}O_{3}, where accurate experimental data became available recently from a comprehensive generalized ellipsometry investigation [Phys. Rev. B 93, 125209 (2016)]. Data for triclinic crystal systems can be measured by generalized ellipsometry as well, and are anticipated to become available soon and results can be compared with the generalized relations presented here.

  19. MEMFIS - Measuring, modelling and forecasting ice loads on structures - Final report

    Energy Technology Data Exchange (ETDEWEB)

    Dierer, S.; Cattin, R.

    2010-05-15

    This illustrated final report for the Swiss Federal Office of Energy (SFOE) takes a look at the icing-up of structures such as overhead power lines, wind turbines and aerial cableways in mountainous or arctic areas. The measurement of icing at three locations in Switzerland, in the high Alps, the alpine foothills and the Jura mountains using a vertical freely-rotating cylinder is described. Problems encountered during the measurement campaigns are described and discussed. The development of a simulation system in parallel to the measurement campaign is also discussed. A comparison of measured and simulated data calculated with the WRF and COSMO models was made difficult as a result of the problems encountered with the apparatus used. The basic effects causing icing-up are discussed and the measurement apparatus used is examined.

  20. Surface, optical characteristics and photocatalytic ability of Scheelite-type monoclinic Bi3FeMo2O12 nanoparticles

    Science.gov (United States)

    Nie, Xinming; Wulayin, Wumitijiang; Song, Tingting; Wu, Minxiao; Qiao, Xuebin

    2016-11-01

    Bi3FeMo2O12 nanoparticles with the Scheelite-type monoclinic structure were prepared by the Pechini synthesis. The Bi3FeMo2O12 nanoparticle has a size of about 50 nm. The phase formation and structural characteristic were studied by X-ray diffraction (XRD) patterns and Rietveld refinements. The Scheelite framework is characterized by a superstructure constructed by the ordered arrangement of Fe/Mo tetrahedral on the B sites. The surface characteristics of Bi3FeMo2O12 nanoparticles were studied by the measurements such as the scanning electron microscope (SEM), the transmission electron microscopy (TEM), and the N2-adsorption-desorption isotherm. Bi3FeMo2O12 nanoparticles present an efficient optical absorption in a wide wavelength region from UV to 540 nm. The band gap energy was decided to be 2.3 eV and characterized by a direct allowed electronic optical transition. The photocatalytic activity of Bi3FeMo2O12 nanoparticles was confirmed by the photodegradation of the rhodamine B (RhB) dye solution. The experiments indicate that the Scheelite-type molybdate could be a potential candidate of a visible-light-driven photocatalyst.

  1. A second monoclinic polymorph of 2-(diformylmethylidene-3,3-dimethyl-2,3-dihydro-1H-indole

    Directory of Open Access Journals (Sweden)

    Hamid Khaledi

    2009-10-01

    Full Text Available The crystal structure of the title compound, C13H13NO2, is a polymorph of the structure first reported by Helliwell et al. [Acta Cryst. (2006, E62, o737-o738]. It is also monoclinic (space group P21/c, but with completely different cell constants. The molecular conformations of these polymorphs differ by a 180° rotation of one formyl group. The present molecule is planar [maximum deviation 0.089 (2 Å] with the exception of the two methyl groups which lie on either side of the plane. There are strong intra- and intermolecular N—H...O hydrogen bonds. The latter link pairs of molecules across crystallographic centers of symmetry. Two aldehyde O atoms are brought close together [2.896 (4 Å in this arrangement but are not hydrogen bonded. In the earlier polymorph, one formyl group is rotated by 180° to yield intermolecular hydrogen bonding and an infinite polymeric chain. The other formyl group is involved in the same intramolecular hydrogen bonding as has been found here.

  2. A near-peer teaching program designed, developed and delivered exclusively by recent medical graduates for final year medical students sitting the final objective structured clinical examination (OSCE

    Directory of Open Access Journals (Sweden)

    Sobowale Oluwaseun

    2011-03-01

    Full Text Available Abstract Background The General Medical Council states that teaching doctors and students is important for the care of patients. Our aim was to deliver a structured teaching program to final year medical students, evaluate the efficacy of teaching given by junior doctors and review the pertinent literature. Methods We developed a revision package for final year medical students sitting the Objective Structured Clinical Examination (OSCE. The package was created and delivered exclusively by recent medical graduates and consisted of lectures and small group seminars covering the core areas of medicine and surgery, with a focus on specific OSCE station examples. Students were asked to complete a feedback questionnaire during and immediately after the program. Results One hundred and eighteen completed feedback questionnaires were analysed. All participants stated that the content covered was relevant to their revision. 73.2% stated that junior doctors delivered teaching that is comparable to that of consultant - led teaching. 97.9% stated the revision course had a positive influence on their learning. Conclusions Our study showed that recent medical graduates are able to create and deliver a structured, formal revision program and provide a unique perspective to exam preparation that was very well received by our student cohort. The role of junior doctors teaching medical students in a formal structured environment is very valuable and should be encouraged.

  3. Identification of monoclinic calcium pyrophosphate dihydrate and hydroxyapatite in human sclera using Raman microspectroscopy

    DEFF Research Database (Denmark)

    Chen, Ko-Hua; Li, Mei-Jane; Cheng, Wen-Ting;

    2009-01-01

    Raman microspectroscopy was first used to determine the composition of a calcified plaque located at the pterygium-excision site of a 51-year-old female patient's left nasal sclera after surgery. It was unexpectedly found that the Raman spectrum of the calcified sample at 1149, 1108, 1049, 756, 517...... to the characteristic peak at 958/cm of hydroxyapatite (HA). This is the first study to report the spectral biodiagnosis of both monoclinic CPPD and HA co-deposited in the calcified plaque of a patient with sclera dystrophic calcification using Raman microspectroscopy....

  4. Structure-Reactivity Relationships in Multi-Component Transition Metal Oxide Catalysts FINAL Report

    Energy Technology Data Exchange (ETDEWEB)

    Altman, Eric I. [Yale Univ., New Haven, CT (United States)

    2015-10-06

    The focus of the project was on developing an atomic-level understanding of how transition metal oxide catalysts function. Over the course of several renewals the specific emphases shifted from understanding how local structure and oxidation state affect how molecules adsorb and react on the surfaces of binary oxide crystals to more complex systems where interactions between different transition metal oxide cations in an oxide catalyst can affect reactivity, and finally to the impact of cluster size on oxide stability and reactivity. Hallmarks of the work were the use of epitaxial growth methods to create surfaces relevant to catalysis yet tractable for fundamental surface science approaches, and the use of scanning tunneling microscopy to follow structural changes induced by reactions and to pinpoint adsorption sites. Key early findings included the identification of oxidation and reduction mechanisms on a tungsten oxide catalyst surface that determine the sites available for reaction, identification of C-O bond cleavage as the rate limiting step in alcohol dehydration reactions on the tungsten oxide surface, and demonstration that reduction does not change the favored reaction pathway but rather eases C-O bond cleavage and thus reduces the reaction barrier. Subsequently, a new reconstruction on the anatase phase of TiO2 relevant to catalysis was discovered and shown to create sites with distinct reactivity compared to other TiO2 surfaces. Building on this work on anatase, the mechanism by which TiO2 enhances the reactivity of vanadium oxide layers was characterized and it was found that the TiO2 substrate can force thin vanadia layers to adopt structures they would not ordinarily form in the bulk which in turn creates differences in reactivity between supported layers and bulk samples. From there, the work progressed to studying well-defined ternary oxides where synergistic effects between the two cations can induce

  5. Monoclinic Hydroxyapatite Nanoplates Hybrid Composite with Improved Compressive Strength, and Porosity for Bone Defect Repair: Biomimetic Synthesis and Characterization.

    Science.gov (United States)

    Xue, Bo; Farghaly, Ahmed A; Guo, Zhenzhao; Zhao, Pengg; Li, Hong; Zhou, Changren; Li, Lihua

    2016-03-01

    Calcium phosphate cement (CPC) has been used for bone restoration despite its intrinsic fragile property. In order to enhance the CPC mechanical properties, biopolymers were introduced as filler to prepare CPC based cements. Chitosan/tetracalcium phosphate (TTCP)/dicalcium phosphate anhydrous (DCPA) based cement for bone repair has been prepared in the study. Solidification of the prepared cement was carried out in a simulate body fluid at 37 degrees C. The introduction of chitosan improved the mechanical performance of the as-prepared CPC hybrid nanocomposite. FTIR, SEM, TEM, HRTEM, XRD, and SAED were used to characterize the CPC nanocomposite. Data simulations have been performed to assist in determining the crystalline phase/s in the CPC hybrid nanocomposite. Based on the SAED, HRTEM measurements and data simulations, a monoclinic phase of hydroxyapatite (HAP) with a plate-like structure was obtained in the CPC system, which is believed to be responsible for the observed enhancement in CPC mechanical properties. The obtained composite has a biocompatibility comparable to that of commercial sample.

  6. The giant piezoelectric effect: electric field induced monoclinic phase or piezoelectric distortion of the rhombohedral parent?

    CERN Document Server

    Kisi, E H; Forrester, J S; Howard, C J

    2003-01-01

    Lead zinc niobate-lead titanate (PZN-PT) single crystals show very large piezoelectric strains for electric fields applied along the unit cell edges e.g. [001] sub R. It has been widely reported that this effect is caused by an electric field induced phase transition from rhombohedral (R3m) to monoclinic (Cm or Pm) symmetry in an essentially continuous manner. Group theoretical analysis using the computer program ISOTROPY indicates phase transitions between R3m and Cm (or Pm) must be discontinuous under Landau theory. An analysis of the symmetry of a strained unit cell in R3m and a simple expansion of the piezoelectric strain equation indicate that the piezoelectric distortion due to an electric field along a cell edge in rhombohedral perovskite-based ferroelectrics is intrinsically monoclinic (Cm), even for infinitesimal electric fields. PZN-PT crystals have up to nine times the elastic compliance of other piezoelectric perovskites and it might be expected that the piezoelectric strains are also very large. ...

  7. Imaging metal-like monoclinic phase stabilized by surface coordination effect in vanadium dioxide nanobeam

    Science.gov (United States)

    Li, Zejun; Wu, Jiajing; Hu, Zhenpeng; Lin, Yue; Chen, Qi; Guo, Yuqiao; Liu, Yuhua; Zhao, Yingcheng; Peng, Jing; Chu, Wangsheng; Wu, Changzheng; Xie, Yi

    2017-06-01

    In correlated systems, intermediate states usually appear transiently across phase transitions even at the femtosecond scale. It therefore remains an open question how to determine these intermediate states--a critical issue for understanding the origin of their correlated behaviour. Here we report a surface coordination route to successfully stabilize and directly image an intermediate state in the metal-insulator transition of vanadium dioxide. As a prototype metal-insulator transition material, we capture an unusual metal-like monoclinic phase at room temperature that has long been predicted. Coordinate bonding of L-ascorbic acid molecules with vanadium dioxide nanobeams induces charge-carrier density reorganization and stabilizes metallic monoclinic vanadium dioxide, unravelling orbital-selective Mott correlation for gap opening of the vanadium dioxide metal-insulator transition. Our study contributes to completing phase-evolution pathways in the metal-insulator transition process, and we anticipate that coordination chemistry may be a powerful tool for engineering properties of low-dimensional correlated solids.

  8. Final Scientific/Technical Report: Low Cost, Structurally Advanced Novel Electrode and Cell Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Woodford, William [24M Technologies, Inc., Cambridge, MA (United States)

    2017-01-10

    This document is the final technical report from 24M Technologies on the project titled: Low Cost, Structurally Advanced Novel Electrode and Cell Manufacturing. All of the program milestones and deliverables were completed during the performance of the award. Specific accomplishments are 1) 24M demonstrated the processability and electrochemical performance of semi-solid electrodes with active volume contents increased by 10% relative to the program baseline; 2) electrode-level metrics, quality, and yield were demonstrated at an 80 cm2 electrode footprint; 3) these electrodes were integrated into cells with consistent capacities and impedances, including cells delivered to Argonne National Laboratory for independent testing; 4) those processes were scaled to a large-format (> 260 cm2) electrode footprint and quality and yield were demonstrated; 5) a high-volume manufacturing approach for large-format electrode fabrication was demonstrated; and 6) large-format cells (> 100 Ah capacity) were prototyped with consistent capacity and impedance, including cells which were delivered to Argonne National Laboratory for independent testing.

  9. The non-independence discussion about cycle structure in the computer language: the final simplification of computer language in the structural design

    Science.gov (United States)

    Yang, Peilu

    2013-03-01

    In the first place, the article discusses the theory, content, development, and questions about structured programming design. The further extension on this basement provides the cycle structure in computer language is the sequence structure, branch structure, and the cycle structure with independence. Through the deeply research by the writer, we find the non-independence and reach the final simplification about the computer language design. In the first, the writer provides the language structure of linear structure (I structure) and curvilinear structure (Y structure). This makes the computer language has high proficiency with simplification during the program exploration. The research in this article is corresponding with the widely used dualistic structure in the computer field. Moreover, it is greatly promote the evolution of computer language.

  10. Orthorhombic-to-monoclinic phase transition of Ta2NiSe5 induced by the Bose-Einstein condensation of excitons

    Science.gov (United States)

    Kaneko, T.; Toriyama, T.; Konishi, T.; Ohta, Y.

    2013-01-01

    Using the band structure calculation and mean-field analysis of the derived three-chain Hubbard model with phonon degrees of freedom, we discuss the origin of the orthorhombic-to-monoclinic phase transition of the layered chalcogenide Ta2NiSe5. We show that the Bose-Einstein condensation of excitonic electron-hole pairs cooperatively induces the instability of the phonon mode at momentum q→0 in the quasi-one-dimensional Ta-NiSe-Ta chain, resulting in the structural phase transition of the system. The calculated single-particle spectra reproduce the deformation of the band structure observed in the angle-resolved photoemission spectroscopy experiment.

  11. Orientation relationships between icosahedral clusters in hexagonal MgZn2 and monoclinic Mg4Zn7 phases in Mg-Zn(-Y) alloys

    Science.gov (United States)

    Rosalie, Julian M.; Somekawa, Hidetoshi; Singh, Alok; Mukai, Toshiji

    2011-07-01

    Intermetallic precipitates formed in heat-treated and aged Mg-Zn and Mg-Zn-Y alloys have been investigated via electron microscopy. Coarse spheroidal precipitates formed on deformation twin boundaries contained domains belonging to either the MgZn2 hexagonal Laves phase or the monoclinic Mg4Zn7 phase. Both phases are structurally related to the quasi-crystalline phase formed in Mg-Zn-Y alloys, containing icosahedrally coordinated zinc atoms arranged as a series of broad rhombohedral units. This rhombohedral arrangement was also visible in intragranular precipitates where local regions with the structures of hexagonal MgZn2 and Mg4Zn7 were found. The orientation adopted by the MgZn2 and Mg4Zn7 phases in twin-boundary and intragranular precipitates was such that the icosahedral clusters were aligned similarly. These results highlight the close structural similarities between the precipitates of the Mg-Zn-Y alloy system.

  12. Discovery of Fe7O9: a new iron oxide with a complex monoclinic structure

    OpenAIRE

    Ryosuke Sinmyo; Elena Bykova; Ovsyannikov, Sergey V.; Catherine McCammon; Ilya Kupenko; Leyla Ismailova; Leonid Dubrovinsky

    2016-01-01

    Iron oxides are fundamentally important compounds for basic and applied sciences as well as in numerous industrial applications. In this work we report the synthesis and investigation of a new binary iron oxide with the hitherto unknown stoichiometry of Fe7O9. This new oxide was synthesized at high-pressure high-temperature (HP-HT) conditions, and its black single crystals were successfully recovered at ambient conditions. By means of single crystal X-ray diffraction we determined that Fe7O9 ...

  13. KINETIC STUDY OF SELECTIVE GAS-PHASE OXIDATION OF ISOPROPANOL TO ACETONE USING MONOCLINIC ZRO2 AS A CATALYST

    Directory of Open Access Journals (Sweden)

    Mohammad Sadiq

    2015-08-01

    Full Text Available Zirconia was prepared by a precipitation method and calcined at 723 K, 1023 K, and 1253 K in order to obtain monoclinic zirconia. The prepared zirconia was characterized by XRD, SEM, EDX, surface area and pore size analyzer, and particle size analyzer. Monoclinic ZrO2 as a catalyst was used for the gas-phase oxidation of isopropanol to acetone in a Pyrex-glass-flow-type reactor with a temperature range of 443 K - 473 K. It was found that monoclinic ZrO2 shows remarkable catalytic activity (68% and selectivity (100% for the oxidation of isopropanol to acetone. This kinetic study reveals that the oxidation of isopropanol to acetone follows the L-H mechanism.

  14. A monoclinic polymorph of (R,R-4,4′-dibromo-2,2′-[cyclohexane-1,2-diylbis(nitrilomethanylylidene]diphenol

    Directory of Open Access Journals (Sweden)

    Kwang Ha

    2012-05-01

    Full Text Available The title compound, C20H20Br2N2O2, a tetradentate Schiff base, is the enantiomerically pure R,R-diastereomer of four possible stereoisomers. The molecular structure reveals two strong intramolecular O—H...N hydrogen bonds between the hydroxy O atom and the imino N atom, which each generate S(6 rings. In the crystal, molecules are stacked in columns along the a axis; when viewed down the b axis, successive columns are stacked in the opposite direction. The structure reported herein is the monoclinic polymorph of the previously reported orthorhombic form [Yi & Hu (2009. Acta Cryst. E65, o2643], in which the complete molecule is generated by a crystallographic twofold axis.

  15. Stress-induced VO{sub 2} films with M2 monoclinic phase stable at room temperature grown by inductively coupled plasma-assisted reactive sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Okimura, Kunio; Watanabe, Tomo [School of Engineering, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); Sakai, Joe [GREMAN, UMR 7347 CNRS, Universite Francois Rabelais de Tours, Parc de Grandmont 37200 Tours (France)

    2012-04-01

    We report on growth of VO{sub 2} films with M2 monoclinic phase stable at room temperature under atmospheric pressure. The films were grown on quartz glass and Si substrates by using an inductively coupled plasma-assisted reactive sputtering method. XRD-sin{sup 2}{Psi} measurements revealed that the films with M2 phase are under compressive stress in contrast to tensile stress of films with M1 phase. Scanning electron microscopy observations revealed characteristic crystal grain aspects with formation of periodical twin structure of M2 phase. Structural phase transition from M2 to tetragonal phases, accompanied by a resistance change, was confirmed to occur as the temperature rises. Growth of VO{sub 2} films composed of M2 phase crystalline is of strong interest for clarifying nature of Mott transition of strongly correlated materials.

  16. Cubic or monoclinic Y 2O 3:Eu 3+ nanoparticles by one step flame spray pyrolysis

    Science.gov (United States)

    Camenzind, Adrian; Strobel, Reto; Pratsinis, Sotiris E.

    2005-11-01

    Continuous, single-step synthesis of monocrystalline Y 2O 3:Eu 3+ nanophosphor particles (10-25 nm in diameter and 5 wt% Eu) was achieved by flame spray pyrolysis (FSP). The effect of FSP process parameters on materials properties was investigated by X-ray diffraction (XRD), nitrogen adsorption (BET) and transmission electron microscopy (TEM). Photoluminescence (PL) emission were measured as well as the time-resolved PL-intensity decay. Controlled synthesis of monoclinic or cubic Y 2O 3:Eu 3+ nanoparticles was achieved without post-treatment by controlling the high temperature residence time of these particles. The cubic nanoparticles exhibited longer decay times but lower maximum PL intensity than commercial micron-sized bulk Y 2O 3:Eu 3+ phosphor powder.

  17. A monoclinic polymorph of (1E,5E-1,5-bis(2-hydroxybenzylidenethiocarbonohydrazide

    Directory of Open Access Journals (Sweden)

    Bonell Schmitt

    2011-08-01

    Full Text Available The title compound, C15H14N4O2S, is a derivative of thioureadihydrazide. In contrast to the previously reported polymorph (orthorhombic, space group Pbca, Z = 8, the current study revealed monoclinic symmetry (space group P21/n, Z = 4. The molecule shows non-crystallographic C2 as well as approximate Cs symmetry. Intramolecular bifurcated O—H...(N,S hydrogen bonds, are present. In the crystal, intermolecular N—H...S hydrogen bonds and C—H...π contacts connect the molecules into undulating chains along the b axis. The shortest centroid–centroid distance between two aromatic systems is 4.5285 (12 Å.

  18. Calculation of thermodynamic, electronic, and optical properties of monoclinic Mg2NiH4

    Energy Technology Data Exchange (ETDEWEB)

    Myers, W.R.; Richardson, T.J.; Rubin, M.D.; Wang, L-W.

    2001-10-01

    Ab initio total-energy density functional theory is used to investigate the low temperature (LT) monoclinic form of Mg2NiH4. The calculated minimum energy geometry of LT Mg2NiH4 is close to that determined from neutron diffraction data, and the NiH4 complex is close to a regular tetrahedron. The enthalpies of the phase change to high temperature (HT) pseudo-cubic Mg2NiH4 and of hydrogen absorption by Mg2Ni are calculated and compared with experimental values. LT Mg2NiH4 is found to be a semiconductor with an indirect band gap of 1.4 eV. The optical dielectric function of LT Mg2NiH4 differs somewhat from that of the HT phase. A calculated thin film transmittance spectrum is consistent with an experimental spectrum.

  19. Monoclinic phase transformation and mechanical durability of zirconia ceramic after fatigue and autoclave aging.

    Science.gov (United States)

    Mota, Yasmine A; Cotes, Caroline; Carvalho, Rodrigo F; Machado, João P B; Leite, Fabíola P P; Souza, Rodrigo O A; Özcan, Mutlu

    2017-10-01

    This study evaluated the influence of two aging procedures on the biaxial flexural strength of yttria-stabilized tetragonal zirconia ceramics. Disc-shaped zirconia specimens and (ZE: E.max ZirCAD, Ivoclar; ZT: Zirkon Translucent, Zirkonzahn) (N = 80) (∅:12 mm; thickness:1.2 mm, ISO 6872) were prepared and randomly divided into four groups (n = 10 per group) according to the aging procedures: C: Control, no aging; M: mechanical cycling (2 × 10(6) cycles/3.8 Hz/200 N); AUT: Aging in autoclave at 134°C, 2 bar for 24 h; AUT + M: Autoclave aging followed by mechanical cycling. After aging, the transformed monoclinic zirconia (%) were evaluated using X-ray diffraction and surface roughness was measured using atomic force microscopy. The average grain size was measured by scanning electron microscopy and the specimens were submitted to biaxial flexural strength testing (1 mm/min, 1000 kgf in water). Data (MPa) were statistically analyzed using 2-way analysis of variance and Tukey's test (α = 0.05). Aging procedures significantly affected (p = 0.000) the flexural strength data but the effect of zirconia type was not significant (p = 0.657). AUTZT (936.4 ± 120.9(b) ) and AUT + MZE (867.2 ± 49.3(b) ) groups presented significantly higher values (p autoclave aging alone or with mechanical aging increased the flexure strength but also induced higher transformation from tetragonal to monoclinic phase in both zirconia materials tested. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1972-1977, 2017. © 2016 Wiley Periodicals, Inc.

  20. Structural Features of the Final Intermediate in the Biosynthesis of the Lantibiotic Nisin. Influence of the Leader Peptide

    NARCIS (Netherlands)

    Hooven, Henno W. van den; Rollema, Harry S.; Siezen, Roland J.; Hilbers, Cornelis W.; Kuipers, Oscar P.

    1997-01-01

    The antimicrobial membrane-interacting polypeptide nisin is a prominent member of the lantibiotic family, the members of which contain thioether-bridged residues called lanthionines. To gain insight into the complex biosynthesis and the structure/function relationship of lantibiotics, the final inte

  1. Influence of the monoclinic and tetragonal zirconia phases on the water gas shift reaction. A theoretical study.

    Science.gov (United States)

    Cerón, María Luisa; Herrera, Barbara; Araya, Paulo; Gracia, Francisco; Toro-Labbé, Alejandro

    2013-07-01

    We present a theoretical study of the water gas shift reaction taking place on zirconia surfaces modeled by monoclinic and tetragonal clusters. In order to understand the charge transfer between the active species, in this work we analyze the influence of the geometry of monoclinic and tetragonal zirconia using reactivity descriptors such as electronic chemical potential (μ), charge transfer (ΔN) and molecular hardness (η). We have found that the most preferred surface is tetragonal zirconia (tZrO2) indicating also that low charge transfer systems will generate less stable intermediates, that will allow to facilitate desorption process.

  2. Application of RPR to Monoclinic and Triclinic Symmetries: Initial Results on Elasticity of Single-Crystal Diopside

    Science.gov (United States)

    Isaak, D. G.; Ohno, I.

    2001-12-01

    In past years, the rectangular parallelepiped resonance (RPR) method has been used to measure single-crystal elastic moduli, and their temperature dependences, of several materials important to geophysics. The high-temperature elastic properties of cubic, orthorhombic, tetragonal, and trigonal crystals, in addition to polycrystals, have all been studied with the RPR method. One feature of the RPR method is that, in principle, all the single-crystal elastic moduli (Cij) can be obtained from a single spectral sweep. However, no materials with crystal symmetry lower than orthorhombic symmetry have been reported in RPR studies. We extend the RPR theory to monoclinic and triclinic crystal symmetries. With these developments, we are able to compute single-crystal resonant spectra using a set of assumed Cij for right-rectangular parallelepiped monoclinic specimens cut along the b and c axes, or monoclinic specimens cut along known, but arbitrary, axes. We present initial results showing the comparison of calculated and measured resonance modes for single-crystal monoclinic diopside. Our measured resonance spectrum on chrome diopside is markedly more consistent with the spectrum calculated from the elasticity data of Collins and Brown (PCM, 26, 7-13, 1998) using a specimen that is 72% diopside than the end-member diopside elasticity data reported by Levien et al. (PCM, 4, 105-113, 1979).

  3. Coexistence of different charge states in Ta-doped monoclinic HfO2: Theoretical and experimental approaches

    DEFF Research Database (Denmark)

    Taylor, M.A.; Alonso, R.E.; Errico, L.A.

    2010-01-01

    A combination of experiments and ab initio quantum-mechanical calculations has been applied to examine hyperfine interactions in Ta-doped hafnium dioxide. Although the properties of monoclinic HfO2 have been the subject of several earlier studies, some aspects remain open. In particular, time dif...

  4. Final Progress Report: FRACTURE AND SUBCRITICAL DEBONDING IN THIN LAYERED STRUCTURES: EXPERIMENTS AND MULTI-SCALE MODELING

    Energy Technology Data Exchange (ETDEWEB)

    Reinhold H. Dauskardt

    2005-08-30

    Final technical report detailing unique experimental and multi-scale computational modeling capabilities developed to study fracture and subcritical cracking in thin-film structures. Our program to date at Stanford has studied the mechanisms of fracture and fatigue crack-growth in structural ceramics at high temperature, bulk and thin-film glasses in selected moist environments where we demonstrated the presence of a true mechanical fatigue effect in some glass compositions. We also reported on the effects of complex environments and fatigue loading on subcritical cracking that effects the reliability of MEMS and other micro-devices using novel micro-machined silicon specimens and nanomaterial layers.

  5. Structural evolution of trimesic acid (TMA)/Zn2 + ion network on Au(111) to final structure of (10√3 × 10√3)

    Science.gov (United States)

    Kim, Jandee; Lee, Jaesung; Rhee, Choong Kyun

    2016-02-01

    Presented is a scanning tunneling microscopy (STM) study of structural evolution of TMA/Zn2 + ion network on Au(111) to the final structure of (10√3 × 10√3) during solution phase post-modification of pristine trimesic acid (TMA) network of a (5√3 × 5√3) structure with Zn2 + ions. Coordination of Zn2 + ions into adsorbed TMA molecules transforms crown-like TMA hexamers in pristine TMA network to chevron pairs in TMA/Zn2 + ion network. Two ordered transient structures of TMA/Zn2 + ion network were observed. One is a (5√7 × 5√7) structure consisting of Zn2 + ion-containing chevron pairs and Zn2 + ion-free TMA dimers. The other is a (5√39 × 5√21) structure made of chevron pairs and chevron-pair-missing sites. An STM image showing domains of different stages of crystallization of chevron pairs demonstrates that the TMA/Zn2 + network before reaching to the final one is quite dynamic. The observed structural evolution of the TMA/Zn2 + ion network is discussed in terms of modification of configurations of adsorbed TMA as accommodating Zn2 + ions and re-ordering of Zn2 + ion-containing chevron pairs.

  6. Structural Studies of Bacterial Enzymes and their Relation to Antibiotic Resistance Mechanisms - Final Paper

    Energy Technology Data Exchange (ETDEWEB)

    Maltz, Lauren [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-27

    By using protein crystallography and X-ray diffraction, structures of bacterial enzymes were solved to gain a better understanding of how enzymatic modification acts as an antibacterial resistance mechanism. Aminoglycoside phosphotransferases (APHs) are one of three aminoglycoside modifying enzymes that confer resistance to the aminoglycoside antibiotics via enzymatic modification, rendering many drugs obsolete. Specifically, the APH(2”) family vary in their substrate specificities and also in their preference for the phosphate donor (ADP versus GDP). By solving the structures of members of the APH(2”) family of enzymes, we can see how domain movements are important to their substrate specificity. Our structure of the ternary complex of APH(2”)-IIIa with GDP and kanamycin, when compared to the known structures of APH(2”)-IVa, reveals that there are real physical differences between these two enzymes, a structural finding that explains why the two enzymes differ in their preferences for certain aminoglycosides. Another important group of bacterial resistance enzymes are the Class D β- lactamases. Oxacillinase carbapenemases (OXAs) are part of this enzyme class and have begun to confer resistance to ‘last resort’ drugs, most notably carbapenems. Our structure of OXA-143 shows that the conformational flexibility of a conserved hydrophobic residue in the active site (Val130) serves to control the entry of a transient water molecule responsible for a key step in the enzyme’s mechanism. Our results provide insight into the structural mechanisms of these two different enzymes

  7. Phonon instability and pressure-induced isostructural semiconductor-semimetal transition of monoclinic V O2

    Science.gov (United States)

    He, Huabing; Gao, Heng; Wu, Wei; Cao, Shixun; Hong, Jiawang; Yu, Dehong; Deng, Guochu; Gao, Yanfeng; Zhang, Peihong; Luo, Hongjie; Ren, Wei

    2016-11-01

    Recent experiments have revealed an intriguing pressure-induced isostructural transition of the low temperature monoclinic V O2 and hinted to the existence of a new metallization mechanism in this system. The physics behind this isostructural phase transition and the metallization remains unresolved. In this work, we show that the isostructural transition is a result of pressure-induced instability of a phonon mode that relates to a CaC l2 -type of rotation of the oxygen octahedra, which alleviates, but does not completely remove, the dimerization and zigzagging arrangement of V atoms in the M1 phase. This phonon mode shows an increasing softening with pressure, ultimately leading to an isostructural phase transition characterized by the degree of the rotation of the oxygen octahedra. We also find that this phase transition is accompanied by an anisotropic compression, in excellent agreement with experiments. More interestingly, in addition to the experimentally identified M1' phase, we find a closely related M1 '' phase, which is nearly degenerate with the M1 ' phase. Unlike the M1 ' phase, which has a nearly pressure-independent electronic band gap, the gap of the M1 '' drops quickly at high pressures and vanishes at a theoretical pressure of about 40 GPa.

  8. Monoclinic BiVO{sub 4} with regular morphologies: Hydrothermal synthesis, characterization and photocatalytic properties

    Energy Technology Data Exchange (ETDEWEB)

    Li Haibin [School of Materials Science and Engineering, Central South University, Changsha 410083 (China)], E-mail: coastllee@hotmail.com; Liu Guocong [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Department of Chemistry, Yulin Normal University, Yulin 537000 (China); Duan Xuechen [School of Materials Science and Engineering, Central South University, Changsha 410083 (China)

    2009-05-15

    Monoclinic bismuth vanadate (BiVO{sub 4}) samples with regular morphologies were prepared by a facile hydrothermal process with Bi{sub 2}O{sub 3} and NH{sub 4}VO{sub 3} as starting materials. The physical and photophysical properties of the as-prepared samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), infrared spectroscopy (IR), and UV-vis diffuse reflectance spectroscopy (UV-vis). It was found that cuboid-like, square plate-like and flower-like BiVO{sub 4} could be readily obtained by tailoring the pH values of the reaction suspensions in the presence of CTAB. Both pH value and CTAB played crucial roles in the morphology evolution of the as-prepared samples. The bandgaps (E{sub g}) of cuboid-like, square plate-like and flower-like BiVO{sub 4} were 2.39 eV, 2.40 eV and 2.46 eV, respectively. The photocatalytic performance of the as-prepared BiVO{sub 4} was much better than that of P25 for photodegradation of methyl orange under sunlight irradiation. The photocatalytic activities of BiVO{sub 4} samples were highly related to their crystallinities and shapes.

  9. Vibrational Spectroscopy and Phonon-Related Properties of the L-Aspartic Acid Anhydrous Monoclinic Crystal.

    Science.gov (United States)

    Silva, A M; Costa, S N; Sales, F A M; Freire, V N; Bezerra, E M; Santos, R P; Fulco, U L; Albuquerque, E L; Caetano, E W S

    2015-12-10

    The infrared absorption and Raman scattering spectra of the monoclinic P21 l-aspartic acid anhydrous crystal were recorded and interpreted with the help of density functional theory (DFT) calculations. The effect of dispersive forces was taken into account, and the optimized unit cells allowed us to obtain the vibrational normal modes. The computed data exhibits good agreement with the measurements for low wavenumbers, allowing for a very good assignment of the infrared and Raman spectral features. The vibrational spectra of the two lowest energy conformers of the l-aspartic molecule were also evaluated using the hybrid B3LYP functional for the sake of comparison, showing that the molecular calculations give a limited description of the measured IR and Raman spectra of the l-aspartic acid crystal for wavenumbers below 1000 cm(-1). The results obtained reinforce the need to use solid-state calculations to describe the vibrational properties of molecular crystals instead of calculations for a single isolated molecule picture even for wavenumbers beyond the range usually associated with lattice modes (200 cm(-1) < ω < 1000 cm(-1)).

  10. Switch effect of the nonquantized intrinsic spin Hall conductivity in monolayered monoclinic transition metal dichalcogenides

    Science.gov (United States)

    Lin, Xianqing; Ni, Jun

    2017-07-01

    First-principles calculations have been performed to study the intrinsic spin Hall effect (SHE) and its behavior under vertical electric field in monoclinic transition metal dichalcogenide monolayers (1T‧-MX2 with M  =  Mo, W and X  =  S, Se, Te). We find that the pristine systems exhibit nonquantized intrinsic spin Hall conductivity (SHC) due to the unconserved spin around the direct band gaps though they have nontrivial band topology. The unconserved spin is attributed to the band crossings at Fermi levels for systems without spin-orbit coupling and the distinct composition of the band states around the crossings. Despite the nonquantization of SHC, calculations with the hybrid functional predict SHC approaching the quantized value in W based systems, especially 1T‧-WTe2, which has been realized in experiments. More interesting, a sharp drop of SHC to almost zero in semiconducting systems induced by vertical electric field is observed at the topological phase transition point, suggesting that such systems exhibit a strong switch effect of SHC. In contrast, the switch effect is weak in semi-metallic systems, where the SHC decreases almost continuously with increasing field strength for the chemical potential around the Fermi levels. Our findings suggest potential applications of the pristine 1T‧-MX2 and those under vertical electric field in spintronics devices by utilizing the intrinsic SHE of their bulk states.

  11. USFWS/DU Floating Nest Structure Project Report: 1997 season and final summary

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report presents four-year results from a waterfowl floating nest structure project in the Morris Wetland District, Minnesota. The study was conducted from 1994...

  12. Structural and Dynamic Characterization of Amorphous Solids and Associated Phase Transitions. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Yarger, J. L.

    2000-08-15

    The effect of hydrostatic pressure on the structure of glasses is not well understood. There is extensive evidence now indicating that glasses undergo structural transformation upon application of pressure. These transformations are usually evidenced by changes in density, sound velocity, and structural changes from diffraction measurements (x-ray and neutron). In vitreous GeO{sub 2}, a change in Ge-coordination from 4-6 is evidenced on the application of pressure. The coordination change reverts back to 4 on releasing the pressure indicating that the structural transformation is reversible with pressure. But a shift towards higher Q (inverse space) of the first sharp diffraction peak (FSDP) on the pressure compacted v-SiO{sub 2} and v-GeO{sub 2} suggests that application of pressure has both reversible and irreversible components such that on the release of pressure, the glass remains in a permanently compacted state.

  13. Semiempirical Studies of Atomic Structure. Final Report for July 1, 2000 - June 30, 2003

    Energy Technology Data Exchange (ETDEWEB)

    Curtis, L. J.

    2004-05-01

    This project has developed a comprehensive and reliable base of accurate atomic structure data for complex many-electron systems. This has been achieved through the use of sensitive data-based parametric systematizations, precise experimental measurements, and supporting theoretical computations. The atomic properties studies involved primary data (wavelengths, frequency intervals, lifetimes, relative intensities, production rates, etc.) and derived structural parameters (energy levels, ionization potentials, line strengths, electric polarizabilities, branching fractions, excitation functions, etc).

  14. Temperature effects on chemical structure and motion in coal. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Maciel, G.E.

    1996-09-30

    The objective of this project was to apply recently developed, state-of-the-art nuclear magnetic resonance (NMR) techniques to examine in situ changes in the chemical structure and molecular/macromolecular motion in coal as the temperature is increased above room temperature. Although alterations in the chemical structure of coal have been studied previously by {sup 13}C NMR, using quenched samples, the goal of this project was to examine these chemical structural changes, and changes in molecular/macromolecular mobility that may precede or accompany the chemical changes, at elevated temperatures, using modern {sup 13}C and {sup 1}H NMR techniques, especially {sup 1}H dipolar-dephasing techniques and related experiments pioneered in the laboratory for examining pyridine-saturated coals. This project consisted of the following four primary segments and related efforts on matters relevant to the first four tasks. (1) {sup 1}H NMR characterization of coal structure and mobility as a function of temperature variation over a temperature range (30--240 C) for which substantial chemical transformations were not anticipated. (2) {sup 1}H NMR characterization of coal structure, mobility and conversion as a function of temperature variation over a temperature range (240--500 C) for which chemical transformations of coal are known to occur. (3) {sup 13}C NMR investigation of coal structure/mobility as a function of temperature over a temperature range (30--240 C) for which substantial chemical transformations were not anticipated. (4) {sup 13}C NMR investigation of coal structure, dynamics and conversion as a function of temperature variation over a range (240--500 C) for which chemical transformations of coal are known to occur. (5) Related matters relevant to the first four tasks: (a) {sup 1}H CRAMPS NMR characterization of oil shales and their kerogen concentrates; and (b) improved quantitation in {sup 13}C MAS characterization of coals.

  15. Single crystalline monoclinic La0.7Sr0.3MnO3 nanowires with high temperature ferromagnetism

    Energy Technology Data Exchange (ETDEWEB)

    Carretero-Genevrier, Adrian [ICMAB, Barcelona, Spain; Gazquez Alabart, Jaume [ORNL; Idrobo Tapia, Juan C [ORNL; Oro, Judith [ICMAB, Barcelona, Spain; Arbiol, Jordi [ICMAB, Barcelona, Spain; Varela del Arco, Maria [ORNL; Ferain, Etienne [Universite catholique de Louvain, Belgium (UCL); Rodriguez-Carvajal, Juan [Institut Laue-Langevin (ILL); Puig, Teresa [ICMAB, Barcelona, Spain; Mestres, Narcis [ICMAB, Barcelona, Spain; Obradors, Xavier [ICMAB, Barcelona, Spain

    2011-01-01

    Porous mixed-valent manganese oxides are a group of multifunctional materials that can be used as molecular sieves, catalysts, battery materials, and gas sensors. However, material properties and thus activity can vary significantly with different synthesis methods or process conditions, such as temperature and time. Here, we report on a new synthesis route for MnO{sub 2} and LaSr-doped molecular sieve single crystalline nanowires based on a solution chemistry methodology combined with the use of nanoporous polymer templates supported on top of single crystalline substrates. Because of the confined nucleation in high aspect ratio nanopores and of the high temperatures attained, new structures with novel physical properties have been produced. During the calcination process, the nucleation and crystallization of {var_epsilon}-MnO{sub 2} nanoparticles with a new hexagonal structure is promoted. These nanoparticles generated up to 30 {mu}m long and flexible hexagonal nanowires at mild growth temperatures (T{sub g} = 700 C) as a consequence of the large crystallographic anisotropy of {var_epsilon}-MnO{sub 2}. The nanocrystallites of MnO{sub 2} formed at low temperatures serve as seeds for the growth of La{sub 0.7}Sr{sub 0.3}MnO{sub 3} nanowires at growth temperatures above 800 C, through the diffusion of La and Sr into the empty 1D-channels of {var_epsilon}-MnO{sub 2}. Our particular growth method has allowed the synthesis of single crystalline molecular sieve (LaSr-2 x 4) monoclinic nanowires with composition La{sub 0.7}Sr{sub 0.3}MnO{sub 3} and with ordered arrangement of La{sup 3+} and Sr{sup 2+} cations inside the 1D-channels. These nanowires exhibit ferromagnetic ordering with strongly enhanced Curie temperature (T{sub c} > 500 K) that probably results from the new crystallographic order and from the mixed valence of manganese.

  16. Final Report---Next-Generation Solvers for Mixed-Integer Nonlinear Programs: Structure, Search, and Implementation

    Energy Technology Data Exchange (ETDEWEB)

    Linderoth, Jeff T. [University of Wisconsin-Madison; Luedtke, James R. [University of Wisconsin-Madison

    2013-05-30

    The mathematical modeling of systems often requires the use of both nonlinear and discrete components. Problems involving both discrete and nonlinear components are known as mixed-integer nonlinear programs (MINLPs) and are among the most challenging computational optimization problems. This research project added to the understanding of this area by making a number of fundamental advances. First, the work demonstrated many novel, strong, tractable relaxations designed to deal with non-convexities arising in mathematical formulation. Second, the research implemented the ideas in software that is available to the public. Finally, the work demonstrated the importance of these ideas on practical applications and disseminated the work through scholarly journals, survey publications, and conference presentations.

  17. Nonlinear dynamics and control of SDI structural components. Final report, September 1987-February 1990

    Energy Technology Data Exchange (ETDEWEB)

    Nayfeh, A.H.; Burns, J.A.; Cliff, E.M.

    1990-05-18

    The report summarizes results of experimental and theoretical investigations into the nonlinear response and control of structural elements. Methods for the analysis and design of control procedures applicable to certain nonlinear distributed parameter systems were investigated. Analytical and computational techniques were developed for evaluating the nonlinear effects on control designs. Bench-type experiments were conducted for validating some of the theoretical results.

  18. Fluid-structure interaction in BWR suppression pool systems. Final report. [PELE-IC code

    Energy Technology Data Exchange (ETDEWEB)

    Nickell, R.E.

    1979-09-01

    The discharge of safety relief valves or a severe loss-of-coolant event in a boiling-water-cooled reactor steam supply system triggers a complex pressure suppression system that is based upon sub-surface steam condensation in large pools of water. The physical problems fall into two categories. The first is referred to as vent clearing and describes the process of expelling non-condensables from the system prior to steam flow. The second category covers a variety of phenomena related to the transient overexpansion of a condensable volume and the subsequent inertially-driven volume decrease. The dynamic loading of either event, depending upon fluid-structural design parameters, can be of concern in safety analysis. This report describes the development of a method for calculating the loads and the structural response for both types of problems. The method is embedded in a computer code, called PELE-IC, that couples a two-dimensional, incompressible eulerian fluid algorithm to a finite element shell algorithm. The fluid physics is based upon the SOLA algorithm, which provideds a trial velocity field using the Navier-Stokes equations that is subsequently corrected iteratively so that incompressibility, fluid-structure interface compatibility, and boundary conditions are satisfied. These fluid and fluid-structure algorithms have been extensively verified through calculations of known solutions from the classical literature, and by comparison to air and steam blowdown experiments.

  19. Modelling of space plasma dynamics and structure. Final report, 1 December 1992-30 November 1994

    Energy Technology Data Exchange (ETDEWEB)

    Albert, J.; Anderson, S.; Silevitch, M.; Villalon, E.

    1995-11-01

    The research described in this report was focused into two related areas. These were: (A) A study of nonadiabatic particle orbits and the electrodynamic structure of the coupled magnetosphere ionosphere auroral arc system. (B) An examination of electron acceleration and pitch angle scattering due to wave actions in the ionosphere and radiation belts.

  20. COMPASS: Collaborative Organizational Model to Promote Aligned Support Structures. Final Evaluation Report

    Science.gov (United States)

    Holliday, Lisa; Philp, Joel

    2015-01-01

    In 2010, Iredell-Statesville Schools was awarded an Investing in Innovation grant (i3) from the Office of Innovation and Improvement within the Federal Department of Education. Collaborative Organizational Model to Promote Aligned Support Structures (COMPASS) is a development grant that seeks to meet the needs of students with disabilities,…

  1. Final COMPASS results on the deuteron spin-dependent structure function g1d and the Bjorken sum rule

    Directory of Open Access Journals (Sweden)

    C. Adolph

    2017-06-01

    Full Text Available Final results are presented from the inclusive measurement of deep-inelastic polarised-muon scattering on longitudinally polarised deuterons using a 6LiD target. The data were taken at 160 GeV beam energy and the results are shown for the kinematic range 1(GeV/c24GeV/c2 in the mass of the hadronic final state. The deuteron double-spin asymmetry A1d and the deuteron longitudinal-spin structure function g1d are presented in bins of x and Q2. Towards lowest accessible values of x, g1d decreases and becomes consistent with zero within uncertainties. The presented final g1d values together with the recently published final g1p values of COMPASS are used to again evaluate the Bjorken sum rule and perform the QCD fit to the g1 world data at next-to-leading order of the strong coupling constant. In both cases, changes in central values of the resulting numbers are well within statistical uncertainties. The flavour-singlet axial charge a0, which is identified in the MS‾ renormalisation scheme with the total contribution of quark helicities to the nucleon spin, is extracted at next-to-leading order accuracy from only the COMPASS deuteron data: a0(Q2=3(GeV/c2=0.32±0.02stat±0.04syst±0.05evol. Together with the recent results on the proton spin structure function g1p, the results on g1d constitute the COMPASS legacy on the measurements of g1 through inclusive spin-dependent deep inelastic scattering.

  2. Polarization-dependent angular distribution of the absorption behavior in Ytterbium-doped monoclinic LYB and LGB compounds

    Science.gov (United States)

    Gebremichael, W.; Petit, Y.; Rouzet, S.; Fargues, A.; Veber, P.; Velazquez, M.; Jubera, V.; Canioni, L.; Manek-Hönninger, I.

    2017-02-01

    In this contribution we detail the full characterization of the anisotropy of the absorption properties of two different Yb-doped monoclinic borate compounds under polarized light. The studied crystals are Li6(Gd)0.75Yb0.25(BO3)3 and Li6Y0.75Yb0.25(BO3)3, respectively, grown by the Czochralski method. We focused on the study of their absorption at the zero line transition as a function of the polarization direction of the incident light for two different crystal cuts of each compound. We discuss the different Eigen frames that must be considered in these materials due to their monoclinic character, as well as the optimal crystal orientation for the considered absorption and the potential influences when used as laser materials.

  3. Influence of downsizing of zeolite crystals on the orthorhombic ↔ monoclinic phase transition in pure silica MFI-type

    Science.gov (United States)

    Kabalan, Ihab; Michelin, Laure; Rigolet, Séverinne; Marichal, Claire; Daou, T. Jean; Lebeau, Bénédicte; Paillaud, Jean-Louis

    2016-08-01

    The impact of crystal size on the transition orthorhombic ↔ monoclinic phase in MFI-type purely silica zeolites is investigated between 293 and 473 K using 29Si MAS NMR and powder X-ray diffraction. Three silicalite-1 zeolites are synthesized: a material constituted of micron-sized crystals, pseudospherical nanometer-sized crystals and hierarchical porous zeolites with a mesoporous network created by the use of a gemini-type diquaternary ammonium surfactant giving nanosheet zeolites. Our results show for the first time that the orthorhombic ↔ monoclinic phase transition already known for micron-sized particles also occurs in nanometer-sized zeolite crystals whereas our data suggest that the extreme downsizing of the zeolite crystal to one unit cell in thickness leads to an extinction of the phase transition.

  4. Final report: ES11: The 23rd Annual Workshop on Electronic Structure Methods

    Energy Technology Data Exchange (ETDEWEB)

    Rappe, Andrew M. [Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. of Chemistry

    2011-08-31

    ES11: the 23rd Annual Workshop on Electronic Structure Methods was held from June 6-9, 2011 at the University of Pennsylvania. The local organizing committee (see Section II) led by PI Andrew M. Rappe supervised the organization of the conference, before, during, and after the meeting itself. The national organizing committee set the technical program of talks, and provided support and advice in various ways. The conference was well-attended (see Section III). An important feature of this conference was a series of panel discussions (see Section IV) to discuss the field of electronic structure and to set new directions. The technical program was of extraordinarily high quality (see Section V). The host institution, the University of Pennsylvania, provided a supportive environment for this meeting (see Section VI).

  5. Powder-based synthesis of nanocrystalline material components for structural application. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Ilyuschenko, A.F.; Ivashko, V.S.; Okovity, V.A. [Powder Metallurgy Research Inst., Minsk (Belarus)] [and others

    1998-12-01

    Hydroxiapate spray coatings and substrates for implant production as well as multilayered metal ceramic coatings from nanocrystalline materials are a subject of the investigation. The work aims at the improvement of quality of said objects. This study has investigated the processes of hydroxiapatite powder production. Sizes, shapes and relief of initial HA powder surface are analyzed using SEM and TEM. Modes of HA plasma spraying on a substrate from titanium and associated compositions of traditional and nanocrystalline structure are optimized. The quality of the sprayed samples are studied using X-ray phase analysis and metallographic analysis. The results of investigations of bioceramic coating spraying on titanium are theoretically generalized, taking into account obtained experimental data. The results of investigations of ion-beam technology are presented for spraying multilayered coatings consisting of alternating metal-ceramic layers of nanocrystalline structure.

  6. Structural domains in NADPH: Protochlorophyllide oxidoreductases involved in catalysis and substrate binding. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Timko, Michael P.

    1999-09-24

    Until recently little direct information was available about specific structural determinants within the light-dependent NADPH: protochlorophyllide oxidoreductases (PORs) required for substrate and cofactor binding, catalytic activity, and thylakoid membrane localization. Based on our previous DOE-funded studies, during the past year we brought to fruition a number of ongoing experiments, initiated several new avenues of investigations, and overall have made considerable progress towards establishing the basic structural parameters governing POR function. Our studies to date have defined residues and domains involved in substrate and cofactor binding and catalysis, and elaborated on the mechanism for membrane localization of POR in developing plastids. Our results and their significance, as well as our work in progress, are detailed.

  7. Final Report of Project Nanometer Structures for Fuel Cells and Displays, etc.

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Qing

    2011-12-15

    Low-energy ion beam bombardment induced self-assembly has been used to form various periodic nano-size wave-ordered structures (WOS). Such WOS can be used as hard etching masks to produce nanowire arrays, trenches etc., on other materials by means of traditional etching or ion sputtering. These periodic nano-size structures have a wide range of applications, including flat panel displays, optical electronics, and clean energy technologies (solar and fuel cells, lithium batteries). In order to achieve high throughput of the above processes, a large area RF-driven multicusp nitrogen ion source has been developed for the application of nitrogen ion beam induced surface modification. An integrated ion beam system, which can house either a large area RF-driven multicusp ion source or a commercially available microwave ion source (Roth & Rau AG Tamiris 400-f) have been designed, manufactured, assembled, and tested.

  8. Studies of low temperature, low flux radiation embrittlement of nuclear reactor structural materials. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Odette, G.R.; Lucas, G.E.

    1993-06-01

    There are several existing research programs which have components pertinent to the issue of low flux/low temperature embrittlement; in particular, examination of the Shippingport shield tank which has been exposed to low flux and relatively low temperature is being performed by ANL, and evaluation of low temperature embrittlement in A508 and A533B steels in support of the HTGR is currently being performed by ORNL. However, these programs are not specifically directed at the broader issue of low flux/low temperature embrittlement in a range of structural steels. Hence, the authors coordinated their effort with these programs so that their investigations were complementary to existing programs, and they focused on a set of materials which expand the data base developed in these programs. In particular, the authors have investigated embrittlement phenomena in steels that are similar to those used in support structure.

  9. Nuclear Structure Studies of Exotic Nuclei with Radioactive Ion Beams A Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Winger, Jeff Allen [Mississippi State Univ., Mississippi State, MS (United States)

    2016-04-21

    Beta-decay spectroscopy provides important information on nuclear structure and properties needed to understand topics as widely varied as fundamental nuclear astrophysics to applied nuclear reactor design. However, there are significant limitations of our knowledge due to an inability to experimentally measure everything. Therefore, it is often necessary to rely on theoretical calculations which need to be vetted with experimental results. The focus of this report will be results from experimental research performed by the Principal Investigator (PI) and his research group at Mississippi State University in which the group played the lead role in proposing, implementing, performing and analyzing the experiment. This research was carried out at both the National Superconduction Cyclotron Laboratory (NSCL) at Michigan State University and the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory. The primary emphasis of the research was the use of \\bdec spectroscopy as a tool to understand the evolution of nuclear structure in neutron-rich nuclei which could then be applied to improve theory and to increase the overall knowledge of nuclear structure.

  10. Design of passive piezoelectric damping for space structures. Final Report Ph.D. Thesis

    Science.gov (United States)

    Hagood, Nesbitt W., IV; Aldrich, Jack B.; Vonflotow, Andreas H.

    1994-01-01

    Passive damping of structural dynamics using piezoceramic electromechanical energy conversion and passive electrical networks is a relatively recent concept with little implementation experience base. This report describes an implementation case study, starting from conceptual design and technique selection, through detailed component design and testing to simulation on the structure to be damped. About 0.5kg. of piezoelectric material was employed to damp the ASTREX testbed, a 500kg structure. Emphasis was placed upon designing the damping to enable high bandwidth robust feedback control. Resistive piezoelectric shunting provided the necessary broadband damping. The piezoelectric element was incorporated into a mechanically-tuned vibration absorber in order to concentrate damping into the 30 to 40 Hz frequency modes at the rolloff region of the proposed compensator. A prototype of a steel flex-tensional motion amplification device was built and tested. The effective stiffness and damping of the flex-tensional device was experimentally verified. When six of these effective springs are placed in an orthogonal configuration, strain energy is absorbed from all six degrees of freedom of a 90kg. mass. A NASTRAN finite element model of the testbed was modified to include the six-spring damping system. An analytical model was developed for the spring in order to see how the flex-tensional device and piezoelectric dimensions effect the critical stress and strain energy distribution throughout the component. Simulation of the testbed demonstrated the damping levels achievable in the completed system.

  11. Combustion of pulverized coal in vortex structures. Final report, October 1, 1993--December 31, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Gollahalli, S.R.; Butuk, N.

    1996-03-01

    The objectives of the project were: (i) to understand the effects of heating one of the streams on the characteristics of shear layers, (ii) to investigate the changes in the characteristics of large scale vortex structures in the shear layer caused by the introduction of inert solid particles in one of the feed streams; (iii) to understand the effects of pyrolyzing solids on the shear layer behavior; and (iv) to study the effects of combustion of particles and their pyrolysis products on the shear layer structure, heat release rate, and pollutant emission characteristics. An experimental facility for generating two-dimensional shear layers containing vortex structures has been designed and fabricated. The experimental facility is essentially a low speed wind tunnel designed to (i) provide two gas streams, initially with uniform velocity profiles and isotropic turbulence, mixing at the end of a splitter plate, (ii) introduce vorticity by passively perturbing one of the streams, (iii) allow heating of one of the streams to temperatures high enough to cause pyrolysis of coal particles, and (iv) provide a natural gas flame in one of the streams to result in ignition and burning of coal particles.

  12. Batteries: encapsulated monoclinic sulfur for stable cycling of li-s rechargeable batteries (adv. Mater. 45/2013).

    Science.gov (United States)

    Moon, San; Jung, Young Hwa; Jung, Wook Ki; Jung, Dae Soo; Choi, Jang Wook; Kim, Do Kyung

    2013-12-03

    On page 6547 Do Kyung Kim, Jang Wook Choi and co-workers describe a highly aligned and carbon-encapsulated sulfur cathode synthesized with an AAO template that exhibits a high and long cycle life, and the best rate capability based on the complete encapsulation of sulfur (physical) and implementation of the monoclinic sulfur phase (chemical). © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Theoretical studies in nuclear structure. Final progress report, June 1, 1991--July 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Marshalek, E.R.

    1997-06-01

    The general purview of the project is the theory of collective motion in atomic nuclei. The chief aim is to elucidate the phenomena of (1) anharmonic multiphonon excitations, and (2) collective tilted rotation, both of which are topics of considerable current interest. In the primary stage of an investigation it is often necessary to develop appropriate mathematical tools, as was the case here. In the next stage, the formalism must be tested on simple soluble models. The work described here is mainly concerned with these two stages. The final stage of realistic applications will require more time, manpower and, of course, the necessary funding. Some planning for this last stage has been carried out and anticipated problems axe briefly discussed. As it turns out, both of the above topics can be approached within the unified framework of a theorem that I developed, called the Cranking Bifurcation Theorem (CBT) to be described below. The CBT can be regarded as an outgrowth of the boson expansion method, which provides a general, and, in principal, exact formalism for treating collective excitations. We begin with a brief discussion of the CBT and then continue on to the applications.

  14. Study of magnetic and magnetocaloric properties of monoclinic and triclinic spin chain CoV2O6

    Science.gov (United States)

    Nandi, Moumita; Mandal, Prabhat

    We have investigated magnetic and magnetocaloric properties of both monoclinic and triclinic phases of CoV2O6 from magnetization and heat capacity measurements. Conventional and inverse magnetocaloric effects have been observed in both phases of CoV2O6. For a field change from 0 to 7 T, maximum values of magnetic entropy change and adiabatic temperature change reach 11.8 J kg-1 K-1 and 9.5 K respectively for monoclinic CoV2O6 while the corresponding values reach 12.1 J kg-1 K-1 and 13.1 K for triclinic CoVO6. Particularly for triclinic CoVO6, the magnetocaloric parameters are quite large in low or moderate field range. Apart from this, we have constructed magnetic phase diagram of monoclinic CoV2O6 where field-induced complex magnetic phases appear below a certain critical temperature 6 K when external magnetic field is applied along crystallographic easy axis.

  15. Solvothermal, chloroalkoxide-based synthesis of monoclinic WO(3) quantum dots and gas-sensing enhancement by surface oxygen vacancies.

    Science.gov (United States)

    Epifani, Mauro; Comini, Elisabetta; Díaz, Raül; Andreu, Teresa; Genç, Aziz; Arbiol, Jordi; Siciliano, Pietro; Faglia, Guido; Morante, Joan R

    2014-10-01

    We report for the first time the synthesis of monoclinic WO3 quantum dots. A solvothermal processing at 250 °C in oleic acid of W chloroalkoxide solutions was employed. It was shown that the bulk monoclinic crystallographic phase is the stable one even for the nanosized regime (mean size 4 nm). The nanocrystals were characterized by X-ray diffraction, High resolution transmission electron microscopy, X-ray photoelectron spectroscopy, UV-vis, Fourier transform infrared and Raman spectroscopy. It was concluded that they were constituted by a core of monoclinic WO3, surface covered by unstable W(V) species, slowly oxidized upon standing in room conditions. The WO3 nanocrystals could be easily processed to prepare gas-sensing devices, without any phase transition up to at least 500 °C. The devices displayed remarkable response to both oxidizing (nitrogen dioxide) and reducing (ethanol) gases in concentrations ranging from 1 to 5 ppm and from 100 to 500 ppm, at low operating temperatures of 100 and 200 °C, respectively. The analysis of the electrical data showed that the nanocrystals were characterized by reduced surfaces, which enhanced both nitrogen dioxide adsorption and oxygen ionosorption, the latter resulting in enhanced ethanol decomposition kinetics.

  16. Investigation of 2D laterally dispersive photonic crystal structures : LDRD 33602 final report.

    Energy Technology Data Exchange (ETDEWEB)

    Subramania,Ganapathi Subramanian; Vawter, Gregory Allen; Wendt, Joel Robert; Peake, Gregory Merwin; Guo, Junpeng; Peters, David William; Hadley, G. Ronald

    2003-12-01

    Artificially structured photonic lattice materials are commonly investigated for their unique ability to block and guide light. However, an exciting aspect of photonic lattices which has received relatively little attention is the extremely high refractive index dispersion within the range of frequencies capable of propagating within the photonic lattice material. In fact, it has been proposed that a negative refractive index may be realized with the correct photonic lattice configuration. This report summarizes our investigation, both numerically and experimentally, into the design and performance of such photonic lattice materials intended to optimize the dispersion of refractive index in order to realize new classes of photonic devices.

  17. Structures and functions of oligosaccharins. Final report, December 15, 1989--June 14, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Albersheim, P.

    1994-10-01

    This document contain abstracts of 25 papers published or in preparation describing the structure and function of oligosaccharins. Research is described in the following areas: Phytotoxic effects of microbial pectic enzymes; Fungal enzymes, plant cell wall fragments, and plant cell death; Roles of cell wall constituents in plant-pathogen interactions; The control of morphogenesis in tobacco thin cell-layer explants; Studies of the ability of xyloglucan oligosaccharides to inhibit auxin-stimulated growth; and Oligosaccharins - oligosaccharides that regulate growth, development and defence responses in plants.

  18. ICFD modeling of final settlers - developing consistent and effective simulation model structures

    DEFF Research Database (Denmark)

    Plósz, Benedek G.; Guyonvarch, Estelle; Ramin, Elham

    analysis exercises is kept to a minimum (4). Consequently, detailed information related to, for instance, design boundaries, may be ignored, and their effects may only be accounted for through calibration of model parameters used as catchalls, and by arbitrary amendments of structural uncertainty...... of (6). Further details are shown in (5). Results and discussions Factor screening. Factor screening is carried out by imposing statistically designed moderate (under-loaded) and extreme (under-, critical and overloaded) operational boundary conditions on the 2-D CFD SST model (8). Results obtained...

  19. Improved Structure and Fabrication of Large, High-Power KHPS Rotors - Final Scientific/Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Corren, Dean [Verdant Power, Inc.; Colby, Jonathan [Verdant Power, Inc.; Adonizio, Mary Ann [Verdant Power, Inc.

    2013-01-29

    Verdant Power, Inc, working in partnership with the National Renewable Energy Laboratory (NREL), Sandia National Laboratories (SNL), and the University of Minnesota St. Anthony Falls Laboratory (SAFL), among other partners, used evolving Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) models and techniques to improve the structure and fabrication of large, high-power composite Kinetic Hydropower System (KHPS) rotor blades. The objectives of the project were to: design; analyze; develop for manufacture and fabricate; and thoroughly test, in the lab and at full scale in the water, the improved KHPS rotor blade.

  20. Final Report: Computer Simulation of Osmosis and Reverse Osmosis in Structured Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Sohail Murad

    2012-01-03

    Molecular simulation methods were developed as part of this project to increase our fundamental understanding of membrane based separation systems. Our simulations clarified for example that steric (size) effects had a significant impact on the desalination membranes. Previously it was thought the separation was entirely driven by coulombic force (attractive/repulsive forces at the membrane surfaces). Steric effects played an important role, because salt ions in brackish water are never present alone, but are strongly hydrated which effectively increases their size, and makes it impossible to enter a membrane, while the smaller water molecules can enter more readily. Membrane surface effects did play a role in increasing the flux of water, but not in the separation itself. In addition we also developed simulation methods to study ion exchange, gas separations, and pervaporation. The methods developed were used to once again increase our fundamental understanding of these separation processes. For example our studies showed that when the separation factor of gases in membranes can be significantly affected by the presence of another gas, it is generally because the separation mechanism has changed. For example in the case of nitrogen and carbon dioxide, in their pure state the separation factor is determined by diffusion, while in mixtures it is influenced more by adsorption in the membrane (zeolite in our case) Finally we developed a new technique using the NMR chemical shift to determine intermolecular interactions for mixtures. For polar-nonpolar systems such as Xe dissolved in water we were able to significantly improve the accuracy of gas solubilities, which are very sensitive to the cross interaction between water and Xe.

  1. Laser Wakefield Acceleration: Structural and Dynamic Studies. Final Technical Report ER40954

    Energy Technology Data Exchange (ETDEWEB)

    Downer, Michael

    2014-12-19

    Particle accelerators enable scientists to study the fundamental structure of the universe, but have become the largest and most expensive of scientific instruments. In this project, we advanced the science and technology of laser-plasma accelerators, which are thousands of times smaller and less expensive than their conventional counterparts. In a laser-plasma accelerator, a powerful laser pulse exerts light pressure on an ionized gas, or plasma, thereby driving an electron density wave, which resembles the wake behind a boat. Electrostatic fields within this plasma wake reach tens of billions of volts per meter, fields far stronger than ordinary non-plasma matter (such as the matter that a conventional accelerator is made of) can withstand. Under the right conditions, stray electrons from the surrounding plasma become trapped within these “wake-fields”, surf them, and acquire energy much faster than is possible in a conventional accelerator. Laser-plasma accelerators thus might herald a new generation of compact, low-cost accelerators for future particle physics, x-ray and medical research. In this project, we made two major advances in the science of laser-plasma accelerators. The first of these was to accelerate electrons beyond 1 gigaelectronvolt (1 GeV) for the first time. In experimental results reported in Nature Communications in 2013, about 1 billion electrons were captured from a tenuous plasma (about 1/100 of atmosphere density) and accelerated to 2 GeV within about one inch, while maintaining less than 5% energy spread, and spreading out less than ½ milliradian (i.e. ½ millimeter per meter of travel). Low energy spread and high beam collimation are important for applications of accelerators as coherent x-ray sources or particle colliders. This advance was made possible by exploiting unique properties of the Texas Petawatt Laser, a powerful laser at the University of Texas at Austin that produces pulses of 150 femtoseconds (1 femtosecond is 10

  2. Advancements in sensing and perception using structured lighting techniques :an LDRD final report.

    Energy Technology Data Exchange (ETDEWEB)

    Novick, David Keith; Padilla, Denise D.; Davidson, Patrick A. Jr. (.; .); Carlson, Jeffrey J.

    2005-09-01

    This report summarizes the analytical and experimental efforts for the Laboratory Directed Research and Development (LDRD) project entitled ''Advancements in Sensing and Perception using Structured Lighting Techniques''. There is an ever-increasing need for robust, autonomous ground vehicles for counterterrorism and defense missions. Although there has been nearly 30 years of government-sponsored research, it is undisputed that significant advancements in sensing and perception are necessary. We developed an innovative, advanced sensing technology for national security missions serving the Department of Energy, the Department of Defense, and other government agencies. The principal goal of this project was to develop an eye-safe, robust, low-cost, lightweight, 3D structured lighting sensor for use in broad daylight outdoor applications. The market for this technology is wide open due to the unavailability of such a sensor. Currently available laser scanners are slow, bulky and heavy, expensive, fragile, short-range, sensitive to vibration (highly problematic for moving platforms), and unreliable for outdoor use in bright sunlight conditions. Eye-safety issues are a primary concern for currently available laser-based sensors. Passive, stereo-imaging sensors are available for 3D sensing but suffer from several limitations : computationally intensive, require a lighted environment (natural or man-made light source), and don't work for many scenes or regions lacking texture or with ambiguous texture. Our approach leveraged from the advanced capabilities of modern CCD camera technology and Center 6600's expertise in 3D world modeling, mapping, and analysis, using structured lighting. We have a diverse customer base for indoor mapping applications and this research extends our current technology's lifecycle and opens a new market base for outdoor 3D mapping. Applications include precision mapping, autonomous navigation, dexterous

  3. Stress, seismicity and structure of shallow oil reservoirs of Clinton County, Kentucky. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton-Smith, T. [Kentucky Geological Survey, Lexington, KY (United States)

    1995-12-12

    Between 1993 and 1995 geophysicists of the Los Alamos National Laboratory, in a project funded by the US Department of Energy, conducted extensive microseismic monitoring of oil production in the recently discovered High Bridge pools of Clinton County and were able to acquire abundant, high-quality data in the northern of the two pools. This investigation provided both three-dimensional spatial and kinetic data relating to the High Bridge fracture system that previously had not been available. Funded in part by the Los Alamos National Laboratory, the Kentucky Geological Survey committed to develop a geological interpretation of these geophysical results, that would be of practical benefit to future oils exploration. This publication is a summary of the results of that project. Contents include the following: introduction; discovery and development; regional geology; fractured reservoir geology; oil migration and entrapment; subsurface stress; induced seismicity; structural geology; references; and appendices.

  4. High resolution interface nanochemistry and structure: Final project report, December 1, 1993--February 28, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, R.W.; Lin, S.H.

    1997-02-27

    Work includes studies of interface and grain boundary chemistry and structure in silicon nitride matrix/silicon carbide whisker composites, and in monolithic silicon nitride and silicon carbide synthesized by several different methods. Off-stoichiometric, impurity, and sintering aid elemental distributions in these materials (and other ceramics) have been of great interest because of expected effects on properties but these distributions have proven very difficult to measure because the spatial resolution required is high. The authors made a number of these measurements for the first time, using techniques and instrumentation developed here. Interfaces between metals and SiC are the basis for important metal matrix composites and contacts for high temperature SiC-based solid state electronic devices. The authors have investigated ultrapure interfaces between Ti, Hf, Ti-Hf alloys, Pt, and Co and Si-terminated (0001) 6H SiC single crystals for the first time.

  5. Smart structures for application in ceramic barrier filter technology. Final report, August 1991--August 1994

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, S.J.; Lippert, T.E

    1994-12-01

    High temperature optical fiber sensors were developed to measure the in-service stressing that occurs in ceramic barrier filter systems. The optical fiber sensors were based on improvements to the sensor design developed under the DOE/METC Smart Structures for Fossil Energy Applications contract no. DE-AC21-89MC25159. In-house application testing of these sensors on both candle and cross-flow filters were performed in the Westinghouse Science and Technology Center High-Temperature, High-Pressure Filter Test Facility and the results analyzed. This report summarizes the sensor developments, methods to apply the sensors to the filters for in-situ testing, and the test results from the four in-house tests that were performed.

  6. Ion channel structure. Final technical report, April 1, 1993--March 31, 1997

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-02-01

    During the past decade, endogenous antimicrobial peptides have become recognized as important, ubiquitous, and ancient contributors to the innate mechanisms which permit animals (including humans), and plants to resist infection. Most of these host defense peptides are small (18-35 amino acids), amphipathic and possess either an {alpha}-helical or cystine-stabilized {beta}-sheet structure. These peptides are probably too small for enzymatic function and, so far, no specific receptors have been found. All evidence indicates that their target of action is the lipid matrix of the bacterial cytoplasmic membranes. This project aimed at clarifying the mechanism of peptide-membrane interactions, in particular the pore formation by the peptides which appear to be the mode of action of these antimicrobials. Tremendous progress was made during the project period. We summarize our findings in the following report.

  7. Structural health monitoring of wind turbine blades : SE 265 Final Project.

    Energy Technology Data Exchange (ETDEWEB)

    Barkley, W. C.(Walter C.); Jacobs, Laura D.; Rutherford, A. C.(Amanda C.); Puckett, Anthony

    2006-03-23

    ACME Wind Turbine Corporation has contacted our dynamic analysis firm regarding structural health monitoring of their wind turbine blades. ACME has had several failures in previous years. Examples are shown in Figure 1. These failures have resulted in economic loss for the company due to down time of the turbines (lost revenue) and repair costs. Blade failures can occur in several modes, which may depend on the type of construction and load history. Cracking and delamination are some typical modes of blade failure. ACME warranties its turbines and wishes to decrease the number of blade failures they have to repair and replace. The company wishes to implement a real time structural health monitoring system in order to better understand when blade replacement is necessary. Because of warranty costs incurred to date, ACME is interested in either changing the warranty period for the blades in question or predicting imminent failure before it occurs. ACME's current practice is to increase the number of physical inspections when blades are approaching the end of their fatigue lives. Implementation of an in situ monitoring system would eliminate or greatly reduce the need for such physical inspections. Another benefit of such a monitoring system is that the life of any given component could be extended since real conditions would be monitored. The SHM system designed for ACME must be able to operate while the wind turbine is in service. This means that wireless communication options will likely be implemented. Because blade failures occur due to cyclic stresses in the blade material, the sensing system will focus on monitoring strain at various points.

  8. Final Report: Sampling-Based Algorithms for Estimating Structure in Big Data.

    Energy Technology Data Exchange (ETDEWEB)

    Matulef, Kevin Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-02-01

    The purpose of this project was to develop sampling-based algorithms to discover hidden struc- ture in massive data sets. Inferring structure in large data sets is an increasingly common task in many critical national security applications. These data sets come from myriad sources, such as network traffic, sensor data, and data generated by large-scale simulations. They are often so large that traditional data mining techniques are time consuming or even infeasible. To address this problem, we focus on a class of algorithms that do not compute an exact answer, but instead use sampling to compute an approximate answer using fewer resources. The particular class of algorithms that we focus on are streaming algorithms , so called because they are designed to handle high-throughput streams of data. Streaming algorithms have only a small amount of working storage - much less than the size of the full data stream - so they must necessarily use sampling to approximate the correct answer. We present two results: * A streaming algorithm called HyperHeadTail , that estimates the degree distribution of a graph (i.e., the distribution of the number of connections for each node in a network). The degree distribution is a fundamental graph property, but prior work on estimating the degree distribution in a streaming setting was impractical for many real-world application. We improve upon prior work by developing an algorithm that can handle streams with repeated edges, and graph structures that evolve over time. * An algorithm for the task of maintaining a weighted subsample of items in a stream, when the items must be sampled according to their weight, and the weights are dynamically changing. To our knowledge, this is the first such algorithm designed for dynamically evolving weights. We expect it may be useful as a building block for other streaming algorithms on dynamic data sets.

  9. Thermoelectric-Driven Liquid-Metal Plasma-Facing Structures (TELS) Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Ruzic, David [Univ. of Illinois, Urbana-Champaign, IL (United States)

    2016-12-17

    The Thermoelectric-Driven Liquid-Metal Plasma-Facing Structures (TELS) project was able to establish the experimental conditions necessary for flowing liquid metal surfaces in order to be utilized as surfaces facing fusion relevant energetic plasma flux. The work has also addressed additional developments along with progressing along the timeline detailed in the proposal. A no-cost extension was requested to conduct other relevant experiment- specifically regarding the characterization droplet ejection during energetic plasma flux impact. A specially designed trench module, which could accommodate trenches with different aspect ratios was fabricated and installed in the TELS setup and plasma gun experiments were performed. Droplet ejection was characterized using high speed image acquisition and also surface mounted probes were used to characterize the plasma. The Gantt chart below had been provided with the original proposal, indicating the tasks to be performed in the third year of funding. These tasks are listed above in the progress report outline, and their progress status is detailed below.

  10. Unravelling lignin formation and structure. Final report, April 1, 1988--March 31, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, N.G. [Washington State Univ., Pullman, WA (United States). Inst. of Biological Chemistry

    1991-12-31

    During this study, we established that the Fagaceae exclusively accumulate Z-monolignois/glucosides, and not the E-isomers. Evidence for the presence of a novel E{yields}Z isomerse has been obtained. Our pioneering work in lignin biosynthesis and structure in situ has also progressed smoothly. We established the bonding environments of a woody angiosperm, Leucanea leucocephala, as well as wheat (T. aestivum) and tobacco (N. tabacum). A cell culture system from Pinus taeda was developed which seems ideal for investigating the early stages of lignification. These cultures excrete peroxidase isozymes, considered to be specifically involved in lignin deposition. We also studied the effect of the putative lignin-degrading enzyme, lignin peroxidase, on monolignols and dehydropolymerisates therefrom. In all cases, polymerization was observed, and not degradation; these polymers are identical to that obtained with horseradish peroxidases/H{sub 2}O{sub 2}. It seems inconceivable that these enzymes can be considered as being primarily responsible for lignin biodegradation.

  11. Structure and expression of nuclear genes encoding rubisco activase. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Zielinski, R.E.

    1994-06-01

    Rubisco activase (Rca) is a soluble chloroplast protein that catalyzes the activation of rubisco, the enzyme that initiates the photosynthetic carbon reduction cycle, to catalytic competency. Rca in barley consists of three polypeptides, one of 46- and two of 42-kDa, but the quaternary structure of the protein is not known. The authors have isolated and completely sequenced 8.8 kb of barley genomic DNA containing two, tandemly oriented activase genes (RcaA and RcaB) and three different cDNAs encoding the 42- and 46-kDa Rca polypeptide isoforms. Genomic Southern blot assays indicate that these sequences represent the entire Rca gene family in barley. Pre-mRNAs transcribed from the RcaA gene are alternatively spliced to give mRNAs encoding both 46- (RcaA1) and 42-kDa (RcaA2) Rca isoforms. The RcaB gene encodes a single polypeptide of 42 kDa. Primer extension and northern blot assays indicate that RcaB mRNA is expressed at a level that is 10- to 100-fold lower than RcaA mRNA. Analyses at the mRNA and protein level showed that Rca gene expression is coordinated by that of the rubisco subunits during barley leaf development.

  12. STRUCTURAL FLUCTUATIONS, ELECTRICAL RESPONSE AND THE RELIABILITY OF NANOSTRUCTURES (FINAL REPORT)

    Energy Technology Data Exchange (ETDEWEB)

    Philip J. Rous; Ellen D. Williams; Michael S. Fuhrer

    2006-07-31

    The goal of the research supported by DOE-FG02-01ER45939 was to synthesize a number of experimental and theoretical approaches to understand the relationship between morphological fluctuations, the electrical response and the reliability (failure) of metallic nanostructures. The primary focus of our work was the study of metallic nanowires which we regard as prototypical of nanoscale interconnects. Our research plan has been to link together these materials properties and behaviors by understanding the phenomenon of, and the effects of electromigration at nanometer length scales. The thrust of our research has been founded on the concept that, for nanostructures where the surface-to-volume ratio is necessarily high, surface diffusion is the dominant mass transport mechanism that governs the fluctuations, electrical properties and failure modes of nanostructures. Our approach has been to develop experimental methods that permit the direct imaging of the electromagnetic distributions within nanostructures, their structural fluctuations and their electrical response. This experimental research is complemented by a parallel theoretical and computational program that describes the temporal evolution of nanostructures in response to current flow.

  13. Super Ball Bot - Structures for Planetary Landing and Exploration, NIAC Phase 2 Final Report

    Science.gov (United States)

    SunSpiral, Vytas; Agogino, Adrian; Atkinson, David

    2015-01-01

    Small, light-weight and low-cost missions will become increasingly important to NASA's exploration goals. Ideally teams of small, collapsible, light weight robots, will be conveniently packed during launch and would reliably separate and unpack at their destination. Such robots will allow rapid, reliable in-situ exploration of hazardous destination such as Titan, where imprecise terrain knowledge and unstable precipitation cycles make single-robot exploration problematic. Unfortunately landing lightweight conventional robots is difficult with current technology. Current robot designs are delicate, requiring a complex combination of devices such as parachutes, retrorockets and impact balloons to minimize impact forces and to place a robot in a proper orientation. Instead we are developing a radically different robot based on a "tensegrity" structure and built purely with tensile and compression elements. Such robots can be both a landing and a mobility platform allowing for dramatically simpler mission profile and reduced costs. These multi-purpose robots can be light-weight, compactly stored and deployed, absorb strong impacts, are redundant against single-point failures, can recover from different landing orientations and can provide surface mobility. These properties allow for unique mission profiles that can be carried out with low cost and high reliability and which minimizes the inefficient dependance on "use once and discard" mass associated with traditional landing systems. We believe tensegrity robot technology can play a critical role in future planetary exploration.

  14. Structure induced Yb valence changes in the solid solution Yb(x)Ca(1-x)C2.

    Science.gov (United States)

    Link, Pascal; Glatzel, Pieter; Kvashnina, Kristina; Trots, Dmytro M; Smith, Ronald I; Ruschewitz, Uwe

    2013-06-17

    The solid solution Yb(x)Ca(1-x)C2 (0 ≤ x ≤ 1) was synthesized by reaction of the elements at 1323 K. The crystal structures within this solid solution, as elucidated from synchrotron powder diffraction data, depend on x and exhibit some interesting features that point to a structure dependent valence state of Yb. Compounds with x ≥ 0.75 crystallize in the tetragonal CaC2 type structure (I4/mmm, Z = 2) and obey Vegard's law; for x ≤ 0.75 the monoclinic ThC2 type structure (C2/c, Z = 4) is found, which coexists with the monoclinic CaC2-III type structure (C2/m, Z = 4) for x ≤ 0.25. The monoclinic modifications show a strong deviation from Vegard's law. Their unit cell volumes are remarkably larger than expected for a typical Vegard system. HERFD-XANES spectroscopic investigations reveal that different Yb valence states are responsible for the observed volume anomalies. While all tetragonal compounds contain mixed-valent Yb with ∼75% Yb(3+) (similar to pure YbC2), all monoclinic modifications contain exclusively Yb(2+). Therefore, Yb(x)Ca(1-x)C2 is a very rare example of a Yb containing compound showing a strong structure dependence of the Yb valence state. Moreover, temperature dependent synchrotron powder diffraction, neutron TOF powder diffraction, and HERFD-XANES spectroscopy experiments reveal significant Yb valence changes in some compounds of the Yb(x)Ca(1-x)C2 series that are induced by temperature dependent phase transitions. Transitions from the tetragonal CaC2 type structure to the monoclinic ThC2 or the cubic CaC2-IV type structure (Fm3m, Z = 4) are accompanied by drastic changes of the mean Yb valence from ∼2.70 to 2.0 in compounds with x = 0.75 and x = 0.91. Finally, the determination of lattice strain arising inside the modifications with ordered dumbbells (ThC2 and CaC2 type structures) by DSC measurements corroborated our results concerning the close relationship between crystal structure and Yb valence in the solid solution Yb(x)Ca(1-x

  15. Petrology of Karoo volcanic rocks in the southern Lebombo monocline, Mozambique

    Science.gov (United States)

    Melluso, Leone; Cucciniello, Ciro; Petrone, Chiara M.; Lustrino, Michele; Morra, Vincenzo; Tiepolo, Massimo; Vasconcelos, Lopo

    2008-11-01

    The Karoo volcanic sequence in the southern Lebombo monocline in Mozambique contains different silicic units in the form of pyroclastic rocks, and two different basalt types. The silicic units in the lower part of the Lebombo sequence are formed by a lower unit of dacites and rhyolites (67-80 wt.% SiO 2) with high Ba (990-2500 ppm), Zr (800-1100 ppm) and Y (130-240 ppm), which are part of the Jozini-Mbuluzi Formation, followed by a second unit, interlayered with the Movene basalts, of high-SiO 2 rhyolites (76-78 wt.%; the Sica Beds Formation), with low Sr (19-54 ppm), Zr (340-480 ppm) and Ba (330-850 ppm) plus rare quartz-trachytes (64-66 wt.% SiO 2), with high Nb and Rb contents (240-250 and 370-381 ppm, respectively), and relatively low Zr (450-460 ppm). The mafic rocks found at the top of the sequence are basalts and ferrobasalts belonging to the Movene Formation. The basalts have roughly flat mantle-normalized incompatible element patterns, with abundances of the most incompatible elements not higher than 25 times primitive mantle. The ferrobasalt has TiO 2 ˜ 4.7 wt.%, Fe 2O 3t = 16 wt.%, and high Y (100 ppm), Zr (420 ppm) and Ba (1000 ppm). The Movene basalts have initial (at 180 Ma) 87Sr/ 86Sr = 0.7052-0.7054 and 143Nd/ 144Nd = 0.51232, and the Movene ferrobasalt has even lower 87Sr/ 86Sr (0.70377) and higher 143Nd/ 144Nd (0.51259). The silicic rocks show a modest range of initial Sr-( 87Sr/ 86Sr = 0.70470-0.70648) and Nd-( 143Nd/ 144Nd = 0.51223-0.51243) isotope ratios. The less evolved dacites could have been formed after crystal fractionation of oxide-rich gabbroic cumulates from mafic parental magmas, whereas the most silica-rich rhyolites could have been formed after fractional crystallization of feldspars, pyroxenes, oxides, zircon and apatite from a parental dacite magma. The composition of the Movene basalts imply different feeding systems from those of the underlying Sabie River basalts.

  16. Final Regulations to Reduce Toxic Air Pollutant Emissions from Brick and Structural Clay Products Manufacturing and Clay Ceramics Manufacturing Fact Sheets

    Science.gov (United States)

    This page contains a February 2003 and September 2015 fact sheet with information regarding the final rules to the NESHAP for Brick and Structural Clay Products Manufacturing and the NESHAP for Clay Ceramics Manufacturing

  17. Final Report for Geometric Analysis for Data Reduction and Structure Discovery DE-FG02-10ER25983, STRIPES award # DE-SC0004096

    Energy Technology Data Exchange (ETDEWEB)

    Vixie, Kevin R. [Washington State Univ., Pullman, WA (United States)

    2014-11-27

    This is the final report for the project "Geometric Analysis for Data Reduction and Structure Discovery" in which insights and tools from geometric analysis were developed and exploited for their potential to large scale data challenges.

  18. Single crystal structure of a mixed-chain triacylglycerol: 1,2-dipalmitoyl-3-acetyl-sn-glycerol.

    OpenAIRE

    1992-01-01

    The mixed chain triacylglycerol 1,2-dipalmitoyl-3-acetyl-sn-glycerol was synthesized and its crystal structure was determined to a final reliability factor (R) of 0.11. Two molecules are present in the monoclinic unit cell: space group P2(1); a = 5.375(1), b = 8.286(2), c = 42.96(1) A; beta = 93.30(2) degrees, V = 1910 A3, rho = 1.065 g/cm3, and mu = 5.7 cm-1. The structure is a trilayer: a bilayer of palmitate chains packed in the beta mode (T parallel) and an interdigitated monolayer of ace...

  19. Separated Structure Functions for the Exclusive Electroproduction of K+Lambda and K+Sigma0 Final States

    Energy Technology Data Exchange (ETDEWEB)

    Pawel Ambrozewicz; Daniel Carman; Rob Feuerbach; Mac Mestayer; Brian Raue; Reinhard Schumacher; Avtandil Tkabladze

    2006-11-19

    We report measurements of the exclusive electroproduction of K{sup +}{Lambda} and K{sup +}{Sigma}{sup 0} final states from a proton target using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The separated structure functions {sigma}{sub T}, {sigma}{sub L},{sigma}{sub TT}, and {sigma}{sub LT} were extracted from the {Phi}- and {epsilon}-dependent differential cross sections taken with electron beam energies of 2.567, 4.056, and 4.247 GeV. This analysis represents the first {sigma}{sub L}/{sigma}{sub T} separation with the CLAS detector, and the first measurement of the kaon electroproduction structure functions away from parallel kinematics. The data span a broad range of momentum transfers from 0.5 {le} Q{sup 2} {le} 2.8 GeV{sup 2} and invariant energy from 1.6 {le} W {le} 2.4 GeV, while spanning nearly the full center-of-mass angular range of the kaon. The separated structure functions reveal clear differences between the production dynamics for the {Lambda} and {Sigma}{sup 0} hyperons. These results provide an unprecedented data sample with which to constrain current and future models for the associated production of strangeness, which will allow for a better understanding of the underlying resonant and non-resonant contributions to hyperon production.

  20. Relationship between Rheological Behaviour and Final Structure of Al2O3 and YSZ Foams Produced by Replica

    Directory of Open Access Journals (Sweden)

    S. Y. Gómez

    2012-01-01

    Full Text Available Using rheological parameters of ceramic suspensions, it is possible to taylor the structure of the ceramic foams produced by replica. This method consists in the impregnation of a polymeric flexible template (polyurethane foam with a ceramic suspension (slurry containing the appropriate additives, followed by burning out organic compounds and additives and sintering the ceramic structure. In this work, ceramic foams were produced by the replica method from Al2O3 and 3% Y2O3-ZrO2. Rheological parameters of the ceramic suspensions were investigated to improve the mechanical performance of final structures. Different types and quantities of raw materials were combined in order to select the formulations for ceramic foams. The parameters that have a significant influence on the process are the binder type and the amount of solids. Significant changes on the hysteresis area of the suspensions resulted in a lower density of macrodefects in the material. Likewise, when the shear rate viscosity is enhanced, the thickness of the struts increased proportionally. Lastly, when the hysteresis area magnitude and the ceramic thickness increased, the material with higher uniformity was internally densified, and the stress concentration of the internal defects was smoothed

  1. Separated Structure Functions for the Exclusive Electroproduction of $K^+\\Lambda$ and $K^+\\Sigma^0$ Final States

    CERN Document Server

    Ambrozewicz, P; Feuerbach, R J; Mestayer, M D; Raue, B A; Schumacher, R A; Tkabladze, A; al, et

    2006-01-01

    We report measurements of the exclusive electroproduction of $K^+\\Lambda$ and $K^+\\Sigma^0$ final states from a proton target using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The separated structure functions $\\sigma_T$, $\\sigma_L$, $\\sigma_{TT}$, and $\\sigma_{LT}$ were extracted from the $\\Phi$- and $\\epsilon$-dependent differential cross sections taken with electron beam energies of 2.567, 4.056, and 4.247 GeV. This analysis represents the first $\\sigma_L/\\sigma_T$ separation with the CLAS detector, and the first measurement of the kaon electroproduction structure functions away from parallel kinematics. The data span a broad range of momentum transfers from $0.5\\leq Q^2\\leq 2.8$ GeV$^2$ and invariant energy from $1.6\\leq W\\leq 2.4$ GeV, while spanning nearly the full center-of-mass angular range of the kaon. The separated structure functions reveal clear differences between the production dynamics for the $\\Lambda$ and $\\Sigma^0$ hyperons. These results provide an unprecedente...

  2. Growth, vibrational and luminescence analysis of monoclinic KGd(1-x)Prx(WO4)2 (x=0.005, 0.02, 0.05) single crystals

    Science.gov (United States)

    Thangaraju, D.; Moorthy Babu, S.; Durairajan, A.; Balaji, D.; Samuel, P.; Hayakawa, Y.

    2013-01-01

    Growth of pure KGW, 0.5, 2 and 5 wt% Pr3+ doped KGd(WO4)2 single crystals were carried out using top seeded solution growth (TSSG) method with K2WO4 as flux. Growth parameters that include the cooling rate and pulling rate were modified to achieve transparent doped crystals to that of pure crystals. Optically polished samples were used for optical and structural studies. Structure of grown crystals was confirmed and lattice parameter values were calculated using single crystal X-ray diffractometer. Both pure and doped crystals belong to the monoclinic phase with C2/c space group. When compared to pure matrix of KGW, some notable changes were observed in the lattice parameter values of doped crystals. It may be due to the ionic radii mismatch of replacing praseodymium ion in the place of gadolinium ion. Absorption and emission measurements were carried out for the 2 mm thick polished samples. The doped samples show a very good transparency with an intense absorption band around the blue region of the spectrum with additional absorption peaks in the IR region as well. Strong red emission was observed in the emission spectrum. The energy levels and their corresponding transitions were figured out in Pr3+ ions inside the matrix. Emission characteristics were compared for different dopant concentration. Raman spectra reveal the intense tungstate vibrational modes in the higher frequency region. Comparison of pure and doped samples reveal that there is no significant change in vibrational modes at higher doping concentration.

  3. The NN final-state interaction in the helicity structure of $\\vec d(\\vec\\gamma,\\pi^-)pp$ reaction

    CERN Document Server

    Darwish, E M

    2005-01-01

    The influence of final-state $NN$-rescattering on the helicity structure of the $\\vec\\gamma\\vec d\\to\\pi^-pp$ reaction in the energy range from $\\pi$-threshold up to 550 MeV has been investigated. The differential polarized cross-section difference for the parallel and antiparallel helicity states is predicted and compared with recent experimental data. It is shown that the effect of $NN$-rescattering is much less important in the polarized differential cross-section difference than in the previously studied unpolarized differential cross section. Furthermore, the contribution of $\\vec\\gamma\\vec d\\to\\pi^-pp$ to the spin asymmetry of the deuteron is explicitly evaluated over the region of the $\\Delta$(1232)-resonance with inclusion of $NN$-rescattering. The effect of $NN$ final-state interaction is found to be much larger in the asymmetry than in the total cross section and leads to an appreciable reduction of the spin asymmetry in the $\\Delta$-region.

  4. Synthesis of Monoclinic Form of Gd2-xNaxCuO4 by Direct Precipitation from Molten Salt

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new phase of Gd2-xNaxCuO4 was synthesized by direct precipitation from the mixture of Gd2O3 and CuO in the molten KOH/NaOH/KNO3 solution at temperature as low as 280° C. The resulting precipitate was characterized by using SEM, XRD, EDX, XPS and magnetic method. The XRD data indicate that the precipitated Gd2-xNaxCuO4 is monoclinic with lattice parameters a=8.6816(A), b=3.7233(A). C=6.0796(A), α =γ =90°, β =108.75° and V=186.1(A)3.

  5. Static deformation of two welded monoclinic elastic half-spaces due to a long inclined strike-slip fault

    Indian Academy of Sciences (India)

    Anil Kumar; Sarvajit Singh; Jagdish Singh

    2002-06-01

    Static deformation of two monoclinic elastic half-spaces in welded contact due to a long inclined strike-slip fault situated in one of the half-spaces is studied analytically and numerically. Closedform algebraic expressions for the displacement at any point of the medium are obtained. The variation of the displacement at the interface with the horizontal distance from the fault is studied. The effect of anisotropy on the displacement field is examined. It is found that while the anisotropy of the source half-space has a significant effect on the displacement at the interface, the anisotropy of the other half-space has only a marginal effect.

  6. Doping induced structural transformation in tungsten trioxide

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhijie [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Wu, Shiyun [School of Physics and Mech-Tronic Engineering, Sichuan University of Arts and Science, Dazhou 635000 (China); Wang, Zhiguo, E-mail: zgwang@uestc.edu.cn [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Fu, Y.Q., E-mail: richard.fu@northumbria.ac.uk [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Department of Physics and Electrical Engineering, Faculty of Engineering and Environment, University of Northumbria, Newcastle upon Tyne, NE1 8ST (United Kingdom)

    2016-07-05

    Effects of dopants on structural stability of monoclinic WO{sub 3} were studied using density functional theory. Transformation from monoclinic to cubic crystal structures was obtained by gradually increasing doping concentrations of both rhenium (Re) and electrons inside the monoclinic WO{sub 3}, whereas a large distortion of WO{sub 6} octahedra was observed by gradually increasing doping concentrations of both niobium (Nb) and holes inside the monoclinic WO{sub 3}. It was verified that Re{sub x}W{sub 1-x}O{sub 3} has a cubic structure if x is larger than 0.375, and the transformation from monoclinic to cubic structure is mainly dependent on the occupancy of the W 5d orbital. The elastic characteristics of the Re{sub x}W{sub 1-x}O{sub 3} decrease with the increase of the content of Re in the range of 0.375 ≤ x ≤ 0.875. - Highlights: • Solid state transformations induced by doping in WO{sub 3} were investigated. • Mechanisms of structure transformation induced by doping were clarified. • Re{sub x}W{sub 1-x}O{sub 3} has a cubic structure as x is larger than 0.375. • Electron doping induces the monoclinic to cubic transformation.

  7. DFT insights into the electronic and optical properties of fluorine-doped monoclinic niobium pentoxide (B-Nb{sub 2}O{sub 5}:F)

    Energy Technology Data Exchange (ETDEWEB)

    El-Shazly, Tamer S.; Rehim, Sayed S.A. [Ain-Shams University, Chemistry Department, Faculty of Science, Cairo (Egypt); Hassan, Walid M.I. [Cairo University, Chemistry Department, Faculty of Science, Giza (Egypt); Allam, Nageh K. [American University in Cairo, Energy Materials Lab (EML), School of Sciences and Engineering, New Cairo (Egypt)

    2016-09-15

    We report on the effect of fluorine doping on the electronic structure and optical properties of monoclinic niobium pentoxide (B-Nb{sub 2}O{sub 5}) as revealed by the first principles calculations. Density functional theory (DFT) along with generalized gradient approximation (GGA) at the revised Perdew-Burke-Ernzerhof (PBEsol) exchange-correlation functional was used in this study. The band calculations revealed that the studied materials are indirect bandgap semiconductors, with bandgap energies of 2.67 and 2.28 eV for the undoped and F-doped B-Nb{sub 2}O{sub 5}, respectively. Upon doping B-Nb{sub 2}O{sub 5}, the Fermi level shifts towards the conduction band, allowing optical absorption in the visible region with enhanced transmittance in the wavelength range 400-1000 nm. The calculated static refractive index of the undoped B-Nb{sub 2}O{sub 5} is in good agreement with the reported experimental value, which is enhanced upon F-incorporation resulting in cladding properties for the F-doped B-Nb{sub 2}O{sub 5}. Also, the effective mass of free charge carriers increased upon F-doping. The enhanced properties were attributed to the effect of the excessive valent electron of the incorporated F atom. (orig.)

  8. Surfactant-free synthesis of hyperbranched monoclinic bismuth vanadate and its applications in photocatalysis, gas sensing, and lithium-ion batteries.

    Science.gov (United States)

    Zhao, Yu; Xie, Yi; Zhu, Xi; Yan, Si; Wang, Sunxi

    2008-01-01

    Hyperbranched monoclinic BiVO(4) (h-BiVO(4)) has been synthesized on a large scale and with good uniformity by a surfactant-free hydrothermal route. h-BiVO(4) consists of four trunks with branches distributed on opposite sides. From observation of the intermediates at an early stage of the reaction process, it can be seen that during formation h-BiVO(4) has different growth rates along the a, b, and c axes. Based on crystal structure analysis and experimental results, h-BiVO(4) shows preferential growth along the [100] direction, and subsequently, along the [010] and [001] directions. As-synthesized h-BiVO(4) exhibits excellent photocatalytic ability in the photodegradation reaction of an aqueous solution of RB under visible light. Electrochemical measurements predict that h-BiVO(4) possesses high sensitivity to formaldehyde and ethanol gases, favorable discharge capacity, and capacity retention, which indicate potential applications in the fields of sensing devices and lithium-ion batteries.

  9. Magnetic properties of monoclinic lanthanide metaborates, Ln(BO2)3, Ln  =  Pr, Nd, Gd, Tb

    Science.gov (United States)

    Mukherjee, P.; Suard, E.; Dutton, S. E.

    2017-10-01

    The bulk magnetic properties of the lanthanide metaborates, Ln(BO2)3, Ln  =  Pr, Nd, Gd, Tb are studied using magnetic susceptibility, heat capacity and isothermal magnetisation measurements. They are found to crystallise in a monoclinic structure containing chains of magnetic Ln 3+ and could therefore exhibit features of low-dimensional magnetism and frustration. Pr(BO2)3 is found to have a non-magnetic singlet ground state. No magnetic ordering is observed down to 0.4 K for Nd(BO2)3. Gd(BO2)3 exhibits a sharp magnetic transition at 1.1 K, corresponding to 3D magnetic ordering. Tb(BO2)3 shows two magnetic ordering features at 1.05 K and 1.95 K. A magnetisation plateau at a third of the saturation magnetisation is seen at 2 K for both Nd(BO2)3 and Tb(BO2)3, which persists in an applied field of 14 T. This is proposed to be a signature of quasi 1D behaviour in Nd(BO2)3 and Tb(BO2)3.

  10. Tetrakis(μ2-2,2-dimethylpropanoato-κ2O,O′bis[(pyridine-κNcopper(II]: a monoclinic polymorph

    Directory of Open Access Journals (Sweden)

    Lailatun Nazirah Ozair

    2010-05-01

    Full Text Available The structure of the dinuclear title complex, [Cu2(C5H9O24(C5H5N2], represents a monoclinic polymorph of the previously reported triclinic form [Blewett et al. (2006. Acta Cryst. E62, m420–m422]. Each carboxylate group is bidentate bridging and the distorted octahedral geometry about each CuII atom is completed by a pyridine N atom and the other Cu atom [Cu...Cu = 2.6139 (7 Å]. In the crystal, molecules are connected into supramolecular chains via π–π interactions formed by the pyridine rings [centroid–centroid distance = 3.552 (3 Å] and these are connected into a two-dimensional array in the ac plane by C—H...π contacts. One of the tert-butyl groups is disordered over two orientations in a 0.734 (6:0.266 (6 ratio.

  11. Ab initio calculation of electron-phonon coupling in monoclinic β-Ga2O3 crystal

    Science.gov (United States)

    Ghosh, Krishnendu; Singisetti, Uttam

    2016-08-01

    The interaction between electrons and vibrational modes in monoclinic β-Ga2O3 is theoretically investigated using ab-initio calculations. The large primitive cell of β-Ga2O3 gives rise to 30 phonon modes all of which are taken into account in transport calculation. The electron-phonon interaction is calculated under density functional perturbation theory and then interpolated using Wannier-Fourier interpolation. The long-range interaction elements between electrons and polar optical phonon (POP) modes are calculated separately using the Born effective charge tensor. The direction dependence of the long-range POP coupling in a monoclinic crystal is explored and is included in the transport calculations. Scattering rate calculations are done using the Fermi golden rule followed by solving the Boltzmann transport equation using the Rode's method to estimate low field mobility. A room temperature mobility of 115 cm2/V s is observed. Comparison with recent experimentally reported mobility is done for a wide range of temperatures (30 K-650 K). It is also found that the POP interaction dominates the electron mobility under low electric field conditions. The relative contribution of the different POP modes is analyzed and the mode 21 meV POP is found to have the highest impact on low field electron mobility at room temperature.

  12. Dielectric function and double absorption onset of monoclinic Cu2SnS3

    DEFF Research Database (Denmark)

    Crovetto, Andrea; Chen, Rongzhen; Ettlinger, Rebecca Bolt

    2016-01-01

    in the electronic structure, and this can explain why it has not been reported in earlier calculated spectra. We can now show that the double onset originates from optical transitions at the Γ-point from three energetically close-lying valence bands to a single conduction band. Thus, structural imperfection, like...... secondary phases, is not needed to explain such an absorption spectrum. Finally, we show that the absorption coefficient of CTS is particularly large in the near-band gap spectral region when compared to similar photovoltaic materials....

  13. First Principles Calculation of Elastic Constants of Monoclinic HfO2 Thin Film%单斜相HfO2薄膜弹性常数的第一性原理计算

    Institute of Scientific and Technical Information of China (English)

    蔺玲; 邵淑英; 李静平

    2013-01-01

    用电子束蒸发沉积在K9玻璃基底上镀制HfO2薄膜,沉积温度为200℃,蒸发速率为0.03 nm/s.由X射线衍射谱可知薄膜出现明显结晶,且为单斜相和正交相混合结构,其中单斜相占明显优势.用Jade5软件分析得到单斜相HfO2的晶格常数a,b,c以及晶格矢量a和c之间的夹角β.基于得到的晶格常数建立了单斜相HfO2薄膜的晶体结构模型.同时建立固态单斜相HfO2的晶体结构模型进行对比.通过密度泛函理论(DFT)框架下的平面超软赝势法,采用两种不同的交换关联函数:局域密度近似(LDA)中的CA-PZ和广义梯度近似(GGA)中的质子平衡方程(PBE),计算了薄膜态和固态单斜晶相HfO2的弹性刚度系数矩阵Gij和弹性柔度系数矩阵Sij,Reuss模型、Voigt模型和Hill理论下的体积模量和剪切模量,材料平均杨氏模量和泊松比.此外还计算得到薄膜态和固态单斜晶相HfO2在不同方向上的杨氏模量.%HfO2 films are deposited by electron beam evaporation at a deposition rate of 0.03 nm/s and deposition temperature of 200 ℃ on K9 glass substrates. The films are observed to show a mixed structure of monoclinic and orthorhombic phase through X-ray diffraction and monoclinic phase is of obvious advantages. The structure parameters a, b, c and angel β of monoclinic HfO2 films are obtained using Jade5 software, based on which the crystal structure model is built. While solid crystal monoclinic HfO2 model is built to compare with the thin film one. Elastic stiffness constants of monoclinic HfO2 thin film and solid crystal are investigated using the plane waves ultrasoft pseudopotential technique based on the density functional theory (DFT) under two different exchange correlation functions of local density approximation (LDA) CA-PZ and generalized gradient approximation (GGA) PBE. Reuss, Voigt and Hill theories are used to estimate the bulk, shear and average Young's moduli and Possion ratio for polycrystalline HfO2

  14. Structural Health and Prognostics Management for Offshore Wind Plants; Final Report of Sandia R&D Activities.

    Energy Technology Data Exchange (ETDEWEB)

    Griffith, Daniel Todd [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Wind Energy Technologies Dept.

    2015-04-01

    This final report is a compilation of resear ch efforts - funded by the US Department of Energy Wind and Water Power Technolog ies Office over a four-year period from FY11 through FY14. The goals of this re search program were to develop and evaluate technical innovati ons with promise for maxi mizing revenues and reducing levelized cost of energy (LCOE) for offs hore wind plants - more specifically the goals of the Structural H ealth and Prognostics Management (SHPM) program were to reduce O&M costs and increase energy capture through use of SHPM-based technologies. A technology roadmap was deve loped at the start of the project to guide the research efforts. This roadmap identified and outlined six major research thrust areas each having five stages of ma turity. Research was conducted in each of these thrust areas, as documented throughout this report, although a major focus was on development of damage detection strategi es for the most frequent blade damage conditions and damage mitigation and life-exte nsion strategies via changes in turbine operations (smart loads management). Th e work summarized in this compilation report is the product of the work of many researchers. A summary of the major findings, status of the SHPM Technology Ro admap and recommendations for future work are also provided.

  15. Final Report on "Development and Testing of Advanced Accelerator Structures and Technologies at 11.424 GHz"

    Energy Technology Data Exchange (ETDEWEB)

    Gold, Steven H. [Naval Research Laboratory

    2013-10-13

    This is the final report on the research program ?Development and Testing of Advanced Accelerator Structures and Technologies at 11.424 GHz,? which was carried out by the Naval Research Laboratory (NRL) under Interagency Agreement DE?AI02?01ER41170 with the Department of Energy. The period covered by this report is 15 July 2010 ? 14 July 2013. The program included two principal tasks. Task 1 involved a study of the key physics issues related to the use of high gradient dielectric-loaded accelerating (DLA) structures in rf linear accelerators and was carried out in collaboration with Argonne National Laboratory (ANL) and Euclid Techlabs LLC. Task 2 involved a study of high power active microwave pulse compressors and was carried out in collaboration with Omega-P, Inc. and the Institute of Applied Physics of the Russian Academy of Sciences in Nizhny Novgorod. The studies under Task 1 were focused on rf-induced multipactor and breakdown in externally driven DLA structures at the 200-ns timescale. Suppression of multipactor and breakdown are essential to the practical application of dielectric structures in rf linear accelerators. The structures that were studied were developed by ANL and Euclid Techlabs and their performance was evaluated at high power in the X-band Magnicon Laboratory at NRL. Three structures were designed, fabricated, and tested, and the results analyzed in the first two years of the program: a clamped quartz traveling-wave (TW) structure, a externally copper-coated TW structure, and an externally copper-coated dielectric standing-wave (SW) structure. These structures showed that rf breakdown could be largely eliminated by eliminating dielectric joints in the structures, but that the multipactor loading was omnipresent. In the third year of the program, the focus of the program was on multipactor suppression using a strong applied axial magnetic field, as proposed by Chang et al. [C. Chang et al., J. Appl. Phys. 110, 063304 (2011).], and a

  16. Crystal field analysis of Nd{sup 3+} energy levels in monoclinic NdAl{sub 3}(BO{sub 3}){sub 4} laser

    Energy Technology Data Exchange (ETDEWEB)

    Cascales, C.; Zaldo, C. [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas, Cantoblanco, Madrid (Spain); Caldino, U. [Departamento de Fisica, Universidad Autonoma Metropolitana, Iztapalapa, Mexico DF (Mexico); Garcia Sole, J. [Departamento de Fisica de Materiales, Universidad Autonoma de Madrid, Cantoblanco, Madrid (Spain); Luo, Z.D. [Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian (China)

    2001-09-03

    The energies of 135 Kramers doublets extending up to the {sup 2}H1{sub 11/2} multiplet for Nd{sup 3+} in a monoclinic C2/c space group (No 15) NdAl{sub 3}(BO{sub 3}){sub 4} (NAB) single crystal laser have been determined from polarized optical absorption and photoluminescence measurements at 7 K. The strongly polarized character of the Nd spectra has been discussed under the assumption of a local D{sub 3} symmetry, higher than the C{sub 2} symmetry of NAB, and the observed energy levels have been labelled with the adequate crystal quantum numbers and irreducible representations. A detailed Hamiltonian of 21 parameters has been used in the simulation of the energy levels and associated wavefunctions of the 4f{sup 3} configuration of Nd{sup 3+}. The diagonalized complete energy matrix combines simultaneously the free-ion and single-particle crystal field interactions. Starting B{sup k}{sub q} CF parameters were calculated from the semi-empirical simple overlap model SOM. A comparative simulation considering the C{sub 2} symmetry of NAB is provided. Moreover, two-electron CF interactions as well as an empirical correction have been tested in calculating the anomalous splitting of the {sup 2}H2{sub 11/2} levels. A final fit in D{sub 3} symmetry produces a very good adjustment with a low rms deviation {sigma}=15.3 cm{sup -1} between observed and calculated energy levels. (author)

  17. A simple and low-cost combustion method to prepare monoclinic VO2 with superior thermochromic properties

    Science.gov (United States)

    Cao, Ziyi; Xiao, Xiudi; Lu, Xuanming; Zhan, Yongjun; Cheng, Haoliang; Xu, Gang

    2016-12-01

    In this approach, the VO2 nanoparticles have been successfully fabricated via combusting the low-cost precursor solution consisted of NH4VO3, C2H6O2 and C2H5OH. By the XRD, TEM and XPS analysis, it can be found that the synthetic monoclinic VO2 is single crystal and no impurity is defined. After dispersing the VO2 nanoparticles into the polymer, the solar modulation of VO2-based composite film is up to 12.5% with luminous transmission and haze around 62.2% and 0.5%, respectively. In other words, the composite films show high performance of thermochromic properties. This could open an efficient way to fabricate low-cost and large-scale VO2 (M) nanoparticles and thermochromic films.

  18. Neutron diffraction observations of ferroelastic domain switching and tetragonal-to-monoclinic transformation in Ce-TZP

    Energy Technology Data Exchange (ETDEWEB)

    Kisi, E.H. [Univ. of Newcastle, Callaghan, New South Wales (Australia). Dept. of Mechanical Engineering; Kennedy, S.J.; Howard, C.J. [Australian Nuclear Science and Technology Organisation, Menai, New South Wales (Australia). Neutron Scattering Group

    1997-03-01

    In-situ neutron diffraction has been used to study the plastic deformation of a tetragonal zirconia polycrystal stabilized with 12 mol% ceria under compressive loads up to 1.6 GPa. The development of significant plastic strain in the ceramic has been found to be due to a combination of ferroelastic switching and the tetragonal-to-monoclinic phase transformation, both beginning at {approximately}1.2 GPa. Evidence of a strong coupling between the two phenomena is present. Both transitions are partially reversed on removal of the load. The linear elastic response of the a and c crystal axes of the parent tetragonal phase suggests that the ferroelastic switching occurs directly by a shear mechanism rather than via a cubic intermediate state. Anisotropic distortion of the tetragonal unit cell, as the critical stress is approached, gives some insight into the shear transformation mechanisms.

  19. Density functional theory analysis of Raman frequency modes of monoclinic zirconium oxide using Gaussian basis sets and isotopic substitution.

    Science.gov (United States)

    Daramola, Damilola A; Muthuvel, Madhivanan; Botte, Gerardine G

    2010-07-29

    Geometry and vibration properties for monoclinic zirconium oxide were studied using Gaussian basis sets and LDA, GGA, and B3LYP functionals. Bond angles, bond lengths, lattice parameters, and Raman frequencies were calculated and compared to experimental values. Bond angles and lengths were found to agree within experimental standard deviations. The B3LYP gave the best performance of all three functionals with a percent error of 1.35% for the lattice parameters while the average difference between experimental and calculated Raman frequency values was -3 cm(-1). The B3LYP functional was then used to assign the atomic vibrations causing each frequency mode using isotopic substitution of (93.40)Zr for (91.22)Zr and (18.00)O for (16.00)O. This resulted in seven modes assigned to the Zr atom, ten modes to the O atom, and one mode being a mixture of both.

  20. Surface, optical characteristics and photocatalytic ability of Scheelite-type monoclinic Bi{sub 3}FeMo{sub 2}O{sub 12} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Nie, Xinming, E-mail: nxinming@jsnu.edu.cn; Wulayin, Wumitijiang; Song, Tingting; Wu, Minxiao; Qiao, Xuebin, E-mail: qiaoxb@jsnu.edu.cn

    2016-11-30

    Highlights: • Scheelite-type photocatalyst Bi{sub 3}FeMo{sub 2}O{sub 12} with B-superstructure was developed. • Bi{sub 3}FeMo{sub 2}O{sub 12} has high efficient optical absorption in visible wavelength region. • The narrow band energy 2.3 eV was characterized by direct allowed type. • It presents efficient photodegradation on RhB dye solution driven by visible-light. - Abstract: Bi{sub 3}FeMo{sub 2}O{sub 12} nanoparticles with the Scheelite-type monoclinic structure were prepared by the Pechini synthesis. The Bi{sub 3}FeMo{sub 2}O{sub 12} nanoparticle has a size of about 50 nm. The phase formation and structural characteristic were studied by X-ray diffraction (XRD) patterns and Rietveld refinements. The Scheelite framework is characterized by a superstructure constructed by the ordered arrangement of Fe/Mo tetrahedral on the B sites. The surface characteristics of Bi{sub 3}FeMo{sub 2}O{sub 12} nanoparticles were studied by the measurements such as the scanning electron microscope (SEM), the transmission electron microscopy (TEM), and the N{sub 2}-adsorption–desorption isotherm. Bi{sub 3}FeMo{sub 2}O{sub 12} nanoparticles present an efficient optical absorption in a wide wavelength region from UV to 540 nm. The band gap energy was decided to be 2.3 eV and characterized by a direct allowed electronic optical transition. The photocatalytic activity of Bi{sub 3}FeMo{sub 2}O{sub 12} nanoparticles was confirmed by the photodegradation of the rhodamine B (RhB) dye solution. The experiments indicate that the Scheelite-type molybdate could be a potential candidate of a visible-light-driven photocatalyst.

  1. Association of the pre-internship objective structured clinical examination in final year medical students with comprehensive written examinations.

    Science.gov (United States)

    Eftekhar, Hasan; Labaf, Ali; Anvari, Pasha; Jamali, Arsia; Sheybaee-Moghaddam, Farshad

    2012-01-01

    The purpose of this study is to evaluate the association of the pre-internship Objective Structured Clinical Examination (OSCE) in final year medical students with comprehensive written examinations. SUBJECTS AND MATERIAL: All medical students of October 2004 admission who took part in the October 2010 National Comprehensive Pre-internship Examination (NCPE) and pre-internship OSCE were included in the study (n = 130). OSCE and NCPE scores and medical grade point average (GPA) were collected. GPA was highly correlated with NCPE (r = 0.76 and P<0.001) and moderately with OSCE (r = 0.68 and P < 0.001). Similarly a moderate correlation was observed between NCPE and OSCE scores(r = 0.6 and P < 0.001).Linear stepwise regression shows r(2) of a model applying GPA as predictor of OSCE score is 0.46 (β = 0.68 and P < 0.001), while addition of gender to the model increases r(2) to 0.59 (β = 0.61 and 0.36, for GPA and male gender, respectively and P < 0.001). Logistic forward regression models shows male gender and GPA are the only dependent predictors of high score in OSCE. OR of GPA and male gender for high OSCE score are 4.89 (95% CI = 2.37-10.06) and 6.95 (95% CI = 2.00-24.21), respectively (P < 0.001). Our findings indicate OSCE and examination which mainly evaluate knowledge, judged by GPA and NCPE are moderately to highly correlated. Our results illustrate the interwoven nature of knowledge and clinical skills. In other words, certain level of knowledge is crucial for appropriate clinical performance. Our findings suggest neither OSCE nor written forms of assessments can replace each other. They are complimentary and should also be combined by other evaluations to cover all attributes of clinical competence efficiently.

  2. Molecular structure of two gastrokinetic compounds, cisapride and R53757: comparison with dopaminergic D 2 antagonists

    Science.gov (United States)

    Collin, S.; Vercauteren, D. P.; Evrard, G.; Durant, F.; Tollenaere, J. P.; Moereels, H.

    1989-12-01

    The crystal structures of the title compounds have been solved by direct methods from single crystal X-ray diffraction. Cisapride: monoclinic, space group P2 1/ n with a=34.210(4), b=7.642(2), c=9.435(1) Å, β=90.93(1)°, Z=4, final R factor=0.044 for 1178 observed reflections. R53757: monoclinic, space group P2 1/ n with a=28.896(3), b=8.054(2), c=10.957(2) Å, β=91.79(1)°, Z=4, final R factor=0.032 for 933 observed reflections. Cisapride, a non-dopamine blocking gastrokinetic, and its closely related analog, R53757, are compared to two very potent D 2 antagonists, tropapride and R48788. The analysis of the X-ray determined structures completed by theoretical conformational studies suggests that the structural requirements for all compounds studied seem to be very similar. As shown by PCILO calculations, the presence of a methoxy group on the cisapride piperidine ring does not prevent an optimal orientation of the three putative pharmacophoric elements described for the D 2 receptor. Only the nature of the nitrogen lateral chain differs between the D 2 antagonists and cisapride.

  3. Final « pop-up » structural reactivation of the internal part of an orogenic wedge: west-central Pyrenees

    Science.gov (United States)

    Meresse, F.; Jolivet, M.; Labaume, P.; Teixell, A.

    2009-04-01

    late exhumation stage associated with the tectonic (re)activation of north-vergent thrusts in the northern part of the Axial Zone. Similarly, results from the southern flank of the Axial Zone and the northern part of the Jaca basin suggest a denudation age around 18 Ma (Meresse et al., this volume), which may be linked to out-of-sequence tectonic movements on a south-vergent basement thrust (Bielsa thrust, Jolivet et al., 2007). In conclusion, thermochronological data reveal an Early Miocene "pop-up" exhumation of the internal parts of the Pyrenean wedge, which also shows that the Pyrenean compressional deformation ended later than the generally accepted Aquitanian age deduced from tectonics-sedimentation relationships. This late exhumation was achieved through out-of-sequence (re)activation of hinterland structures linked to a final internal thickening stage in the orogenic prism.

  4. A first principles study of structural stability, electronic structure and mechanical properties of beryllium alanate BeAlH{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Santhosh, M.; Rajeswarapalanichamy, R., E-mail: rajeswarapalanichamy@gmail.com; Priyanga, G. Sudha; Cinthia, A. Jemmy [Department of physics, N.M.S.S.V.N college, Madurai, Tamilnadu-625019 (India); Kanagaprabha, S. [Department of Physics, Kamaraj College, Tuticorin, Tamil Nadu 628003 (India); Iyakutti, K. [Department of Physics and Nanotechnology, SRM University, Chennai, Tamilnadu-603203 (India)

    2015-06-24

    Ab initio calculations are performed to investigate the structural stability, electronic structure and mechanical properties of BeAlH{sub 5} for monoclinic crystal structures with two different types of space group namely P2{sub 1} and C{sub 2}/c. Among the considered structures monoclinic (P2{sub 1}) phase is found to be the most stable at ambient condition. The structural phase transition from monoclinic (P2{sub 1}) to monoclinic (C{sub 2}/c) phase is observed in BeAlH{sub 5}. The electronic structure reveals that this compound is insulator. The calculated elastic constants indicate that this material is mechanically stable at ambient condition.

  5. Monoclinic superstructure of Pr{sub 3}Rh{sub 4}Ge{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Vosswinkel, Daniel; Hoffmann, Rolf-Dieter; Greiwe, Magnus; Eul, Matthias; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

    2016-07-01

    Pr{sub 3}Rh{sub 4}Ge{sub 4} was synthesized by melting of the elements in an arc-melting furnace followed by annealing in a sealed tantalum ampoule in a muffle furnace. Structure refinement was based on temperature dependent single-crystal X-ray diffractometer data. At ambient temperature Pr{sub 3}Rh{sub 4}Ge{sub 4} adopts the U{sub 3}Ni{sub 4}Si{sub 4} type structure with strongly enhanced anisotropic displacement parameters for Rh1. Below 230 K additional reflections start to appear and at 110 K the structure could be described with the (3+1)D superspace group I2/m(α0γ)00; α=1/2, γ=1/2; (Z=2). This commensurately modulated structure could be refined with 1448 F{sup 2} values, 39 variables and residuals of wR=0.0417 for the main reflections and wR=0.1520 for the satellites of 1{sup st} order, [a=408.36(2), b=421.12(3) and c=2504.4(2) pm]. The commensurate description could be transformed to a 3D supercell with space group A2/m and Z=4: a=816.72(2), b=421.12(3), c=2537.5(1) pm, β=99.26(1) , 1448 F{sup 2} values, 69 variables and wR=0.0499. The relation of the U{sub 3}Ni{sub 4}Si{sub 4} type structure, the (3+1)D modulated and the 3D supercell is discussed on the basis of a group-subgroup scheme. Temperature dependent magnetic susceptibility data reveal Curie-Weiss paramagnetism with an experimental moment of 3.72(2) μ{sub B}/Pr atom and a Weiss constant of -12.6(5) K. No magnetic ordering is evident down to 3 K.

  6. A third monoclinic polymorph of 3,4,5-trihydroxybenzoic acid monohydrate

    Directory of Open Access Journals (Sweden)

    Güneş Demirtaş

    2011-06-01

    Full Text Available The title compound, C7H6O5·H2O, is a new polymorph of the structures reported by Jiang et al. (2000 [Acta Cryst. C56, 594–595] and Okabe et al. (2001 [Acta Cryst. E57, o764–o766]. The gallic acid molecule is essentially planar (r.m.s. deviation = 0.550 Å. An intramolecular O—H...O hydrogen bond occurs in the gallic acid molecule, which is linked to the water molecule by a further O—H...O hydrogen bond. In the crystal, the components are linked by O—H...O hydrogen bonds. The hydrogen-bonding pattern differs from those reported for the previous polymorphs.

  7. High pressure monoclinic phases of Sb{sub 2}Te{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Souza, S.M.; Poffo, C.M.; Triches, D.M. [Departamento de Engenharia Mecanica, Universidade Federal de Santa Catarina, Campus Universitario Trindade, S/N, C.P. 476, 88040-900 Florianopolis, Santa Catarina (Brazil); Lima, J.C. de, E-mail: fsc1jcd@fisica.ufsc.br [Departamento de Fisica, Universidade Federal de Santa Catarina, Campus Universitario Trindade, S/N, C.P. 476, 88040-900 Florianopolis, Santa Catarina (Brazil); Grandi, T.A. [Departamento de Fisica, Universidade Federal de Santa Catarina, Campus Universitario Trindade, S/N, C.P. 476, 88040-900 Florianopolis, Santa Catarina (Brazil); Polian, A.; Gauthier, M. [Physique des Milieux Denses, IMPMC, CNRS-UMR 7590, Universite Pierre et Marie Curie-Paris 6, 4 Place Jussieu, 75252 Paris Cedex 05 (France)

    2012-09-15

    The effect of pressure on nanostructured rhombohedral {alpha}-Sb{sub 2}Te{sub 3} (phase I) was investigated using X-ray diffraction (XRD) and Raman spectroscopy (RS) up to 19.2 and 25.5 GPa, respectively. XRD patterns showed two new high pressure phases (named phases II and III). From a Rietveld refinement of XRD patterns of {alpha}-Sb{sub 2}Te{sub 3}, the unit cell volume as a function of pressure was obtained and the values were fitted to a Birch-Murnaghan equation of state (BM-EOS). The best fit was obtained for bulk modulus B{sub 0}=36.1{+-}0.9 GPa and its derivative B{sub 0}{sup Prime }=6.2{+-}0.4 (not fixed). Using the refined structural data for {alpha}-Sb{sub 2}Te{sub 3}, for pressures up to 9.8 GPa, changes in the angle of succession [Te-Sb-Te-Sb-Te], in the interaromic distances of Sb and Te atoms belonging to this angle of succession and in the interatomic distances of atoms located on the c axis were examined. This analysis revealed an electronic topological transition (ETT) along the a and c axes at close to 3.7 GPa. From the RS spectra, the full widths at half maximum (FWHM) of the Raman active modes of {alpha}-Sb{sub 2}Te{sub 3} were plotted as functions of pressure and showed an ETT along the a and c axes at close to 3.2 GPa. The XRD patterns of phases II and III were well reproduced assuming {beta}-Bi{sub 2}Te{sub 3} and {gamma}-Bi{sub 2}Te{sub 3} structures similar to those reported in the literature for {alpha}-Bi{sub 2}Te{sub 3}.

  8. Comparison and validation of Logistic Regression and Analytic Hierarchy Process models of landslide susceptibility in monoclinic regions. A case study in Moldavian Plateau, N-E Romania

    Science.gov (United States)

    Ciprian Margarint, Mihai; Niculita, Mihai

    2014-05-01

    The regions with monoclinic geological structure are large portions of earth surface where the repetition of similar landform patterns is very distinguished, the scarps of cuestas being characterized by similar values of morphometrical variables. Landslides are associated with these scarps of cuestas and consequently, a very high value of landslide susceptibility can be reported on its surface. In these regions, landslide susceptibility mapping can be realized for the entire region, or for test areas, with accurate, reliable, and available datasets, concerning multi-temporal inventories and landslide predictors. Because of the similar geomorphologic and landslide distribution we think that if any relevance of using test areas for extrapolating susceptibility models is present, these areas should be targeted first. This study case try to establish the level of usability of landslide predictors influence, obtained for a 90 km2 sample located in the northern part of the Moldavian Plateau (N-E Romania), in other areas of the same physio-geographic region. In a first phase, landslide susceptibility assessment was carried out and validated using logistic regression (LR) approach, using a multiple landslide inventory. This inventory was created using ortorectified aerial images from 1978 and 2005, for each period being considered both old and active landslides. The modeling strategy was based on a distinctly inventory of depletion areas of all landslide, for 1978 phase, and on a number of 30 covariates extracted from topographical and aerial images (both from 1978 and 2005 periods). The geomorphometric variables were computed from a Digital Elevation Model (DEM) obtained by interpolation from 1:5000 contour data (2.5 m equidistance), at 10x10 m resolution. Distance from river network, distance from roads and land use were extracted from topographic maps and aerial images. By applying Akaike Information Criterion (AIC) the covariates with significance under 0.001 level

  9. The Application of Structured Job Analysis Information Based on the Position Analysis Questionnaire (PAQ). Final Report No. 9.

    Science.gov (United States)

    McCormick, Ernest J.

    The Position Analysis Questionnaire (PAQ) is a job analysis instrument consisting of 187 job elements organized into six divisions. The PAQ was used in the eight studies summarized in this final report. The studies were: (1) ratings of the attribute requirements of PAQ job elements, (2) a series of principal components analyses of these attribute…

  10. Predicting suitable optoelectronic properties of monoclinic VON semiconductor crystals for photovoltaics using accurate first-principles computations

    KAUST Repository

    Harb, Moussab

    2015-08-26

    Using accurate first-principles quantum calculations based on DFT (including the perturbation theory DFPT) with the range-separated hybrid HSE06 exchange-correlation functional, we predict essential fundamental properties (such as bandgap, optical absorption coefficient, dielectric constant, charge carrier effective masses and exciton binding energy) of two stable monoclinic vanadium oxynitride (VON) semiconductor crystals for solar energy conversion applications. In addition to the predicted band gaps in the optimal range for making single-junction solar cells, both polymorphs exhibit relatively high absorption efficiencies in the visible range, high dielectric constants, high charge carrier mobilities and much lower exciton binding energies than the thermal energy at room temperature. Moreover, their optical absorption, dielectric and exciton dissociation properties are found to be better than those obtained for semiconductors frequently utilized in photovoltaic devices like Si, CdTe and GaAs. These novel results offer a great opportunity for this stoichiometric VON material to be properly synthesized and considered as a new good candidate for photovoltaic applications.

  11. Tuning oxygen vacancy photoluminescence in monoclinic Y2WO6 by selectively occupying yttrium sites using lanthanum

    Science.gov (United States)

    Ding, Bangfu; Han, Chao; Zheng, Lirong; Zhang, Junying; Wang, Rongming; Tang, Zilong

    2015-01-01

    The effect of isovalent lanthanum (La) doping on the monoclinic Y2WO6 photoluminescence was studied. Introducing the non-activated La3+ into Y2WO6 brings new excitation bands from violet to visible regions and strong near-infrared emission, while the bands position and intensity depend on the doping concentration. It is interesting to find that doping La3+ into Y2WO6 promotes the oxygen vacancy formation according to the first-principle calculation, Raman spectrum, and synchrotron radiation analysis. Through the Rietveld refinement and X-ray photoelectron spectroscopy results, La3+ is found to mainly occupy the Y2 (2f) site in low-concentration doped samples. With increasing doping concentration, the La3+ occupation number at the Y3 (4g) site increases faster than those at the Y1 (2e) and Y2 (2f) sites. When La3+ occupies different Y sites, the localized energy states caused by the oxygen vacancy pair change their position in the forbidden band, inducing the variation of the excitation and emission bands. This research proposes a feasible method to tune the oxygen vacancy emission, eliminating the challenge of precisely controlling the calcination atmosphere. PMID:25821078

  12. Growth of orthorhombic and tetragonal modifications of TlInS{sub 2} from its monoclinic phase

    Energy Technology Data Exchange (ETDEWEB)

    Alekperov, O.Z.; Ibragimov, G.B.; Axundov, I.A.; Nadjafov, A.I.; Fakix, A.R. [Institute of Physics, Azerbaijan National Academy of Sciences, Baku (Azerbaijan)

    2009-05-15

    Orthorhombic (O) and tetragonal (T) modifications of TlInS{sub 2} were grown by sulfur vapor annealing of monoclinic (M) crystals. Lattice parameters and syngony of the grown crystals were determined from X-ray investigations (Laue, Weissenberg, rocking crystal and powder diffractions). The lattice parameters a =6.88 A, b=14.04 A, c=4.02 A, Z=4 and a=b=7.76 A, c=26.6 A, Z=20 as well as space groups (SG), P2{sub 1}2{sub 1}2{sub 1} and P4{sub 1}2{sub 1}2 were ascribed to O and T modifications, correspondingly. The transition of M-crystals to O- or T-phase takes place through the intermediate disordered state of M-phase in which the unit packets with c{approx}15 A are randomly positioned along the c-axis. From photoconductivity (PC) edge it was found that the band gap of O-TlInS{sub 2} (E{sub g}=2.52{+-}0.01 eV) is slightly higher whereas that of T-TlInS{sub 2} (E{sub g}=1.87{+-}0.01 eV) is noticeably lower than the band gap of M-TlInS{sub 2}. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. Photocatalytic degradation and removal mechanism of ibuprofen via monoclinic BiVO4 under simulated solar light.

    Science.gov (United States)

    Li, Fuhua; Kang, Yapu; Chen, Min; Liu, Guoguang; Lv, Wenying; Yao, Kun; Chen, Ping; Huang, Haoping

    2016-05-01

    Characterized as by X-ray diffraction, scanning electron microscopy and UV-vis diffuse reflectance spectra techniques, BiVO4 photocatalyst was hydrothermally synthesized. The photocatalytic degradation mechanisms of ibuprofen (IBP) were evaluated in aqueous media via BiVO4. Results demonstrated that the prepared photocatalyst corresponded to phase-pure monoclinic scheelite BiVO4. The synthesized BiVO4 showed superior photocatalytic properties under the irradiation of visible-light. The photocatalytic degradation rate of IBP decreased with an increase in the initial IBP concentration. The degradation process followed first-order kinetics model. At an IBP concentration of 10 mg L(-1), while a BiVO4 concentration of 5.0 g L(-1) with pH value of 4.5, the rate of IBP degradation was obtained as 90% after 25 min. The photocatalytic degradation of IBP was primarily accomplished via the generation of superoxide radical (O2(•-)) and hydroxyl radicals ((•)OH). During the process of degradation, part of the (•)OH was converted from the O2(•-). The direct oxidation of holes (h(+)) made a minimal contribution to the degradation of IBP.

  14. Assessment of the effects of microbially influenced degradation on a massive concrete structure. Final report, Report 5

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, R.D. [Biodegradation Systems, Inc., Idaho Falls, ID (United States)

    1995-07-08

    There is a need to estimate the effect of environmental conditions on construction materials to be used in the repository at Yucca Mountain. Previous reports from this project have demonstrated that it is important to develop an understanding of microbially influenced degradation (MID) development and its influence on massive concrete structures. Further, it has been shown that the most effective way to obtain quantitative data on the effects of MID on the structural integrity of repository concrete is to study manmade, analog structures known to be susceptible to MID. The cooling tower shell located at the Ohaaki Power Station near Wairakei, New Zealand is such a structure.

  15. Final Technical Report-Grant # DE-FG02-97ER45628 ?Structural Diorder in Materials?

    Energy Technology Data Exchange (ETDEWEB)

    Stern, Edward A

    2009-02-23

    Since the grant was renewed in 2000 and 2003 final technical reports of the grant have been previously submitted for those years. For that reason this final technical report covers the last four years of the grant. We had an exceptionally successful and productive last four years under the support of the grant. Our progress takes three different aspects, described in more detail below: 1.1 instrumentation, infrastructure, and other research support at Sector 20 of the Advanced Photon Source (APS); 1.2 research on which Profs. Stern or Seidler were PI?s; and 1.3 research on which Profs. Stern or Seidler were co-PI?s or where Drs. Dale Brewe or Julie Cross were authors or co-authors. Drs. Brewe and Cross are the two research scientists (permanently stationed at sector 20) who are supported by the grant. They provide support to the scientific goals of the grant and more broadly provide research support for many general users at Sector 20. Finally, in section 1.4 we provide a complete list of publications resulting from funding in the grant on which at least one of Stern, Seidler, Cross, or Brewe were co-authors. Given the inclusion of operations funding in the grant, this is of course a subset of the full scientific impact of the grant.

  16. Corrosion protection of Arctic offshore structures: Final report. [Effects of temperature and salinity on required cathodic protection current

    Energy Technology Data Exchange (ETDEWEB)

    Sackinger, W.M.; Rogers, J.C.; Feyk, C.; Theuveny, B.

    1985-10-01

    Results are presented for a research program on corrosion prevention for Arctic offshore structures which are in contact with sea ice for a significant portion of the year. The electrical method most adaptable for structure protection involves the injection of impressed current from several remote anodes buried just beneath the sea floor. The electrical resistivity of annual sea ice as a function of temperature and salinity is presented. Details of the interface layers formed between sea ice and steel in the presence of current injection are shown. A computer program was developed to enable the calculation of protective current density into the structure, in the presence of ice rubble and ridges around the structure. The program and the results of an example calculation are given for a caisson- retained island structure. 81 refs., 103 figs., 3 tabs.

  17. Grain size dependent phase stabilities and presence of a monoclinic (Pm) phase in the morphotropic phase boundary region of (1−x)Bi(Mg{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} piezoceramics

    Energy Technology Data Exchange (ETDEWEB)

    Upadhyay, Ashutosh; Singh, Akhilesh Kumar, E-mail: akhilesh-bhu@yahoo.com, E-mail: aksingh.mst@itbhu.ac.in [School of Materials Science and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India)

    2015-04-14

    Results of the room temperature structural studies on (1−x)Bi(Mg{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} ceramics using Rietveld analysis of the powder x-ray diffraction data in the composition range 0.28 ≤ x ≤ 0.45 are presented. The morphotropic phase boundary region exhibits coexistence of monoclinic (space group Pm) and tetragonal (space group P4 mm) phases in the composition range 0.33 ≤ x ≤ 0.40. The structure is nearly single phase monoclinic (space group Pm) in the composition range 0.28 ≤ x ≤ 0.32. The structure for the compositions with x ≥ 0.45 is found to be predominantly tetragonal with space group P4 mm. Rietveld refinement of the structure rules out the coexistence of rhombohedral and tetragonal phases in the morphotropic phase boundary region reported by earlier authors. The Rietveld structure analysis for the sample x = .35 calcined at various temperatures reveals that phase fraction of the coexisting phases in the morphotropic phase boundary region varies with grain size. The structural parameters of the two coexisting phases also change slightly with changing grain size.

  18. Copper(II) ion catalytic oxidation of o-phenylenediamine and characterization, X-ray crystal structure and solution studies of the final product [DAPH][H3O][Cu(dipic)2]·3H2O

    Science.gov (United States)

    Ghasemi, Khaled; Rezvani, Ali Reza; Shokrollahi, Ardeshir; Abdul Razak, Ibrahim; Refahi, Masoud; Moghimi, Abolghasem; Rosli, Mohd Mustaqim

    2015-09-01

    The complex [DAPH][H3O][Cu(dipic)2]·3H2O, (1) (dipicH2 = 2,6-pyridinedicarboxylic acid and DAP = 2,3-diaminophenazine) was prepared from the reaction of Cu(NO3)2·2H2O with mixture of o-phenylenediamine (OPD) and 2,6-pyridinedicarboxylic acid in water. The complex was characterized by FTIR, elemental analysis, UV-Vis and the single-crystal X-ray diffraction. The crystal system is monoclinic with the space group P21/c. This complex is stabilized in the solid state by an extensive network of hydrogen bonds between crystallized water, anionic and cationic fragments, which form a three-dimensional network. Furthermore, hydrogen bonds, π⋯π and Csbnd O⋯π stacking interactions seem to be effective in stabilizing the crystal structures. The protonation constants of dipic (L) and DAP (Q), the equilibrium constants for the dipic-DAP proton transfer system and the stoichiometry and stability constants of binary complexes including each of ligands (dipic, DAP) in presence Cu2+ ion, ternary complexes including, both of ligands (dipic-DAP) in presence of metal ion were calculated in aqueous solutions by potentiometric pH titration method using the Hyperquad2008 program. The stoichiometry of the most complexes species in solution was found to be very similar to the solid-state of cited metal ion complex.

  19. A new monoclinic polymorph of 3-diethylamino-4-(4-methoxyphenyl-1,1-dioxo-4H-1λ6,2-thiazete-4-carbonitrile

    Directory of Open Access Journals (Sweden)

    Ahmed M. Orlando

    2010-08-01

    Full Text Available A new monoclinic form of the title compound, C14H17N3O3S, has been found upon slow crystallization from water. Another monoclinic form of the compound was obtained previously from a mixture of dichloromethane and diethyl ether [Clerici et al. (2002. Tetrahedron, 58, 5173–5178]. Both phases crystallize in space group P21/n with one molecule in the asymmetric unit. The formally single exocyclic C—N bond that connects the –NEt2 unit with the thiazete ring is considerably shorter than the adjacent, formally double, endocyclic C=N bond. This is likely to be due to the extended conjugated system between the electron-donor diethylammine fragment and the electron-withdrawing sulfonyl group. In the newly discovered polymorph, the methoxy group is rotated by almost 180° around the phenyl–OCH3 bond, resulting in a different molecular conformation.

  20. Propagation of SH waves in an regular non homogeneous monoclinic crustal layer lying over a non-homogeneous semi-infinite medium

    Directory of Open Access Journals (Sweden)

    Sethi M.

    2016-05-01

    Full Text Available The present paper discusses the dispersion equation for SH waves in a non-homogeneous monoclinic layer over a semi infinite isotropic medium. The wave velocity equation has been obtained. In the isotropic case, when non-homogeneity is absent, the dispersion equation reduces to the standard SH wave equation. The dispersion curves are depicted by means of graphs for different values of non-homogeneity parameters for the layer and semi-infinite medium.

  1. Synthesis and processing of intelligent cost-effective structures: a final review of the ARPA SPICES program

    Science.gov (United States)

    Jacobs, Jack H.

    1996-05-01

    The Synthesis and Processing of Intelligent Cost Effective Structures (SPICES) program is comprised of a consortium of industrial, academic and government labs working to develop cost effective material processing and synthesis technologies to enable new products using active vibration suppression and control devices to be brought to market. Since smart structures involve the integration of multiple engineering disciplines, it has been the objective of the consortium to establish cost effective design processes between this multi-organizational team for future incorporating of this new technology into each members respective product lines. Over the twenty-four month program many new improvements in sensors, actuators, modeling, manufacturing/integration and controls have been realized. The paper outlines the four phases of development in the program and the impact some of the key technologies will have on the smart structure development process in the future.

  2. Final report WP 4.2: Support Structure Concepts for Deep Water Sites: Deliverable D4.2.8 (WP4: offshore foundations and support structures)

    NARCIS (Netherlands)

    De Vries, W.E.; Vemula, N.K.; Passon, P.; Fischer, T.; Kaufer, D.; Matha, D.; Schmidt, B.; Vorpahl, F.

    2011-01-01

    With the number of offshore wind farms rapidly increasing, in a wide variety of site conditions and using different turbine sizes, the need for alternative support structures other than the conventional monopile structure is apparent and several projects have been realised using other support struct

  3. Final report WP 4.2: Support Structure Concepts for Deep Water Sites: Deliverable D4.2.8 (WP4: offshore foundations and support structures)

    NARCIS (Netherlands)

    De Vries, W.E.; Vemula, N.K.; Passon, P.; Fischer, T.; Kaufer, D.; Matha, D.; Schmidt, B.; Vorpahl, F.

    2011-01-01

    With the number of offshore wind farms rapidly increasing, in a wide variety of site conditions and using different turbine sizes, the need for alternative support structures other than the conventional monopile structure is apparent and several projects have been realised using other support struct

  4. Subsurface stratigraphy and structure of A/M area at the Savannah River Site, Aiken County, South Carolina. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Fallaw, W.C.; Sims, W.R.; Haselow, J.S.

    1991-08-01

    This report is a study of the stratigraphy and structure of the A/M Area Hazardous Waste Management Facility Post-Closure Care Permit process on the Savannah River Site. The data from the lithologic and geophysical logs of 93 wells is the basis of this analysis.

  5. Transport jet aircraft noise abatement in foreign countries: Growth, structure, impact. Volume 1: Europe, July 1980. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, F.A.

    1980-07-01

    The development and implementation of aircraft noise control regulations in various European states are described. The countries include the United Kingdom, France, Switzerland, Federal Republic of Germany, Sweden, Denmark, and the Netherlands. Topics discussed include noise monitoring, airport curfews, land use planning, and the government structure for noise regulation.

  6. Development of Optimal CZTS Device Structure: Cooperative Research and Development Final Report, CRADA Number CRD-12-476

    Energy Technology Data Exchange (ETDEWEB)

    van Hest, Maikel [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-09-01

    Suntricity Corporation and NREL will develop an optimal CZTS device structure. In this process absorber materials provided by Suntricity Corporation will be used for testing. For this purpose Suntricity Corporation will provide dried film precursors or ink precursors. NREL will process these into PV material and complete cells with buffer, window and contacts.

  7. MC carbide structures in M(lc2)ar-M247. M.S. Thesis - Final Report

    Science.gov (United States)

    Wawro, S. W.

    1982-01-01

    The morphologies and distribution of the MC carbides in Mar-M247 ingot stock and castings were investigated using metallographic, X-ray diffraction and energy-dispersive X-ray analysis techniques. The MC carbides were found to form script structures during solidification. The script structures were composed of three distinct parts. The central cores and elongated arms of the MC carbide script structures had compositions (Ti, Cr, Hf, Ta, W)C and lattice parameters of 4.39 A. The elongated script arms terminated in enlarged, angular "heads". The heads had compositions (Ti, Hf, Ta, W)C and lattice parameters of approximately 4.50 A. The heads had a higher Hf content than the cores and arms. The size of the script structures, as well as the relative amount of head-type to core and arm-type MC carbide, was found to be determined by solidification conditions. No carryover of the MC carbides from the ingot stock to the remelted and cast material was observed.

  8. High-pressure structural transformations of PbCrO{sub 4} up to 51.2 GPa: An angle-dispersive synchrotron X-ray diffraction study

    Energy Technology Data Exchange (ETDEWEB)

    Errandonea, D., E-mail: daniel.errandonea@uv.es [Departamento de Física Aplicada-ICMUV, MALTA Consolider Team, Universidad de Valencia, Edificio de Investigación, C/Dr. Moliner 50, Burjassot, 46100 Valencia (Spain); Kumar, R.S. [High Pressure Science and Engineering Center, Department of Physics and Astronomy, University of Nevada Las Vegas, 4505 Maryland Parkway, Las Vegas, Nevada 89154-4002 (United States)

    2014-12-15

    Highlights: • PbCrO{sub 4} was studied under high pressure up to 51 GPa using synchrotron powder XRD. • The occurrence of three phase transitions is reported. • The crystal structures of the high-pressure phases are assigned. • Axial and bulk compressibilities are determined. - Abstract: We report on high-pressure X-ray diffraction measurements up to 51.2 GPa in PbCrO{sub 4} at room temperature. Three high-pressure phases with structures different than the ambient-pressure monazite-type (P2{sub 1}/n) are reported. One phase transition was found at 3.8 GPa to an isomorphic structure to monazite. A second transition occurs at 11.1 GPa. After this transition, the coexistence of tetragonal (I4{sub 1}/a) and monoclinic (P2{sub 1}) structures is detected up to 21.1 GPa. Beyond this pressure and up to 51.2 GPa, only the high-pressure monoclinic phase is observed. Upon decompression all structural changes are reversible. Finally, the axial compressibilities for the different phases have been determined as well as the equations of state.

  9. EFFECT OF PAN-MILLING STRESS ON CRYSTAL STRUCTURES OF HIGH DENSITY POLYETHYLENE

    Institute of Scientific and Technical Information of China (English)

    Hua Huang

    2000-01-01

    A detailed study was performed on the crystal structures of pan-milled high-density polyethylene (HDPE) using differential scanning calorimetry (DSC) and X-ray diffraction. The crystallinity of HDPE first decreased slightly, followed by a gradual increase with increasing milling times. Monoclinic crystals appeared after 4 cycles of milling. With increasing times of milling, the proportion of monoclinic crystals increased significantly while the proportion of orthorhombic crystals decreased gradually. With increasing times of milling, the crystallite size of orthorhombic form decreased greatly, while the size of monoclinic crystallites kept almost constant during milling.

  10. Weathering effects on the structure and reactivity of US coals: Final report, July 15, 1984-July 14, 1987. [Many data

    Energy Technology Data Exchange (ETDEWEB)

    Meuzelaar, H.L.C.; Hill, G.R.; Yun, Yongseung; Jakab, E.; Windig, W.; Urban, D.; Yon, Kyung Yol; Oestreich, J.; East, J.

    1987-01-01

    This report covers the work performed from July 1984 to July 1987 under the project entitled ''Weathering Effects on Structure and Reactivity of US Coals'' (grant number FG22-84PC70798). The main objectives of the study were to investigate the structural changes in coal during the weathering process as well as to develop a simple, reliable weathering index, which can monitor indirectly the weathering-induced changes in physical and chemical properties. Although there have been numerous publications on structure and reactivity of coal, most data reported in the literature thus far have been obtained on coal samples of uncertain weathering status and therefore need to be interpreted with great caution. Weathering has a profound effect on many important coal properties such as heating value, caking characteristics, acidity, flotability and reactivity in liquefaction, combustion and gasification processes. The objective of developing a weathering index is to predict these coal property changes due to weathering without resorting to real-time measurements or pilot plant runs. This report is comprised of four main chapters: I. Structural Changes due to Weathering; II. Material Balance in Weathering Process; III. Development of a Reliable Weathering Index; and IV. Proposed Weathering Mechanisms. A battery of sophisticated analytical tools and techniques was employed during this study. Pyrolysis mass spectrometry in time-integrated, as well as in time-resolved modes with computer-aided data analysis techniques (such as factor and discriminant analysis), gas chromatography, thermogravimetry/mass spectrometry and solvent extraction were used for determining the role of oxygen during the weathering process. Pyrolysis mass spectrometry, Free Swelling Index and a novel slurry pH technique were employed as weathering indicators. 170 refs.

  11. Hybrid density functional study of the structural, bonding, and electronic properties of bismuth vanadate

    Science.gov (United States)

    Kweon, Kyoung E.; Hwang, Gyeong S.

    2012-10-01

    The structure and property prediction of metal oxides can significantly be improved by incorporating exact Hartree-Fock (HF) exchange into density functional theory (DFT), which is the so-called hybrid DFT. We explored the impact of HF exchange inclusion on the predicted structural, bonding, and electronic properties of bismuth vanadate (BiVO4), with particular attention to the difference between its monoclinic and tetragonal scheelite phases. The applied exchange-correlation (xc) functionals include the gradient corrected Perdew-Burke-Ernzerhof (PBE) and the PBE-HF hybrid functionals with HF exchange amounts of 10%, 25%, and 50%. We find that the PBE-HF25% yields a monoclinic structure in very close agreement with the experimentally determined structure, while the PBE-HF50% tends to overestimate the monoclinic distortion and the PBE/PBE-HF10% can hardly identify a distinct monoclinic configuration at ambient conditions. Electronic structure analysis reveals that the increasing monoclinic distortion with the amount of HF exchange is related to the enhancement of hybridization between Bi 6s-O 2p antibonding states and unoccupied Bi 6p states. The bonding mechanisms and band structures of the monoclinic and tetragonal phases of BiVO4 were also investigated, and we discuss how the predictions are sensitive to the xc functional choice.

  12. Environmentally-assisted cracking in austenitic light water reactor structural materials. Final report of the KORA-I project

    Energy Technology Data Exchange (ETDEWEB)

    Seifert, H.-P.; Ritter, S

    2009-03-15

    The following document is the final report of the KORA-I project, which was performed at the Paul Scherrer Institute (PSI) between 2006 and 2008 and was funded by the Swiss Nuclear Safety Inspectorate (ENSI). The three sub-projects of KORA-I covered the experimental characterisation of the effect of the reactor coolant environment on fatigue initiation and crack growth in austenitic stainless steels under boiling and pressurised water reactor conditions, the experimental evaluation of the potential and limits of the electrochemical noise measurement technique for the early detection of stress corrosion cracking initiation in austenitic stainless steels under boiling water reactor/normal water chemistry conditions, as well as the characterisation of the stress corrosion crack growth behaviour in the fusion line region of an Alloy 182-low-alloy reactor pressure vessel steel dissimilar metal weld. The main scientific results and major conclusions of the three sub-projects are discussed in three independent parts of this report. (author)

  13. The change of sowing structure as a strategy for improving competitiveness of family farms directed at the final production of fattened beef cattle

    Directory of Open Access Journals (Sweden)

    Todorović Saša Z.

    2010-01-01

    Full Text Available The aim of this paper is to examine the impact of sowing structure on family farm competiveness using the model of family farm directed at the final production of fattened beef cattle in the conditions of unchanged estate size. Applying a partial budget analysis, it was examined whether the decision on buying alfalfa hay or mercantile maize on the market and changing the sowing structure was economically justified and under what conditions using additional procedure of sensitive analysis. Applying this approach, it was investigated to what extent that decision contributed to improving the family farm profitability. The results of the conducted research show that the decision on buying mercantile maize mainly contributes to improving competitiveness of family farms directed at the final production of fattened beef cattle compared with the decision on buying alfalfa hay. It is the consequence of the fact that buying mercantile maize on the market will enable sowing structure changes, that is, buying mercantile maize will make the area free, which according to some conservative estimations, can be used for the production of sufficient amounts of alfalfa and silage maize for fattening of additional 19 head, whereas buying alfalfa hay will make the area free, which can be used for production of sufficient amounts of mercantile and silage maize for fattening of additional 6 head. In addition, it is shown that more rational way of organizing family farms directed at the final production of fattened beef cattle can additionally use available land resources and in that way increase profitability and improve competitiveness.

  14. Final report for LDRD project {open_quotes}A new approach to protein function and structure prediction{close_quotes}

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, C.A.

    1997-03-01

    This report describes the research performed under the laboratory-Directed Research and Development (LDRD) grant {open_quotes}A new approach to protein function and structure prediction{close_quotes}, funded FY94-6. We describe the goals of the research, motivate and list our improvements to the state of the art in multiple sequence alignment and phylogeny (evolutionary tree) construction, but leave technical details to the six publications resulting from this work. At least three algorithms for phylogeny construction or tree consensus have been implemented and used by researchers outside of Sandia.

  15. Final report for LDRD project {open_quotes}A new approach to protein function and structure prediction{close_quotes}

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, C.A.

    1997-03-01

    This report describes the research performed under the laboratory-Directed Research and Development (LDRD) grant {open_quotes}A new approach to protein function and structure prediction{close_quotes}, funded FY94-6. We describe the goals of the research, motivate and list our improvements to the state of the art in multiple sequence alignment and phylogeny (evolutionary tree) construction, but leave technical details to the six publications resulting from this work. At least three algorithms for phylogeny construction or tree consensus have been implemented and used by researchers outside of Sandia.

  16. Transport jet aircraft noise abatement in foreign countries: Growth, structure, impact. Volume 2: Pacific Basin, August 1980. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, F.A.

    1980-08-01

    Noise control measures at the international airports of Hawaii, New Zealand, Australia, Hong Kong, Japan, and Singapore were studied. Factors in noise control, such as government structure are examined. The increasing power of environmental agencies vis-a-vis aviation departments is noted. The following methods of dealing with aircraft noise are examined by type of control: noise at the source control noise emmission controls, zoning, building codes, subsidies for relocation, insulation, loss in property values, and for TV, radio and telephone interference and noise-related landing charges.

  17. Structure-property characterization of rheocast and VADER processed IN-100 superalloy. Ph.D. Thesis. Final Report

    Science.gov (United States)

    Cheng, J. J. A.; Apelian, D.

    1985-01-01

    Two recent solidification processes have been applied in the production of IN-100 nickel-base superalloy: rheocasting and vacuum arc double electrode remelting (VADER). A detailed microstructural examination has been made of the products of these two processes; associated tensile strength and fatigue crack propagation (FCP) rate at an elevated temperature were evaluated. In rheocasting, processing variables that have been evaluated include stirring speed, isothermal stirring time and volume fraction solid during isothermal stirring. VADER processed IN-100 was purchased from Special Metals Corp., New Hartford, NY. As-cast ingots were subjected to hot isostatic pressing (HIP) and heat treatment. Both rheocasting and VADER processed materials yield fine and equiaxed spherical structures, with reduced macrosegregation in comparison to ingot materials. The rheocast structures are discussed on the basis of the Vogel-Doherty-Cantor model of dendrite arm fragmentation. The rheocast ingots evaluated were superior in yield strength to both VADER and commercially cast IN-100 alloy. Rheocast and VADER ingots may have higher crack propagation resistance than P/M processed material.

  18. First-principles studies of phase stability and the structural and dynamical properties of hydrogen-metal systems. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Chou, M.Y.

    1993-05-01

    First-principles calculations were carried for the hydrogen-yttrium system using the pseudopotential method within the local density functional approximation (LDA). We have studied the nature of hydrogen pairing in the solid solution phase ({alpha}-YH{sub x}.) and identified the connection with electronic structure. The vibrational spectra, diffusion barrier, and migration path were also investigated. We have also studied the binding characteristics for different interstitial sites and the (420)-plane ordering of octahedral hydrogen in {beta}YH{sub 2+x} within the lattice gas model. Temperature-composition phase diagram was calculated by cluster variational method with the multibody interactions extracted from total energies of related ordered structures. Moreover, the discovery of Peierls distortions in YH{sub 3} explained the unusual hydrogen displacements found in neutron diffraction and the possibility of an excitonic insulating ground state was speculated. Several new improvements in the calculational techniques also been developed: Separable nonlocal pseudopotentials, scheme to calculate the full phonon spectrum, and distance dependent tight-binding parameters. The Ru(0001)-H system was also studied.

  19. Comparative analysis of structural concrete quality assurance practices on nine nuclear power plant construction projects. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Willenbrock, J.H.; Thomas, H.R. Jr.; Burati, J.L. Jr.

    1978-06-01

    The basic objective of this research effort was to perform a comparative analysis of the Quality Assurance practices related to the structural concrete phase on nine nuclear power plant projects which are (or have been) under construction in the United States in the past ten years. This analysis identified the response of each Quality Assurance program to the applicable criteria of 10 CFR Part 50, Appendix B as well as to the pertinent regulatory requirements and industry standards. The major emphasis was placed on the construction aspects of the structural concrete phase of each project. The engineering and design aspects were examined whenever they interfaced with the construction aspects. For those aspects of the Quality Assurance system which can be considered managerial in nature (i.e., organizational relationships, types of Quality Assurance programs, corrective action procedures, etc.) an attempt has been made to present the alternative approaches that were identified. For those aspects of the Quality Assurance system which are technical in nature (i.e., the frequency of testing for slump, compressive strength, etc.) an attempt has been made to present a comparative analysis between projects and in relation to the recommended or mandated practices presented in the appropriate industry codes and standards.

  20. Comparative analysis of structural concrete quality assurance practices on three fossil fuel power plant construction projects. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Willenbrock, J.H.; Thomas, H.R. Jr.; Burati, J.L. Jr.

    1978-06-01

    The basic objective of this research effort was to perform a comparative analysis of the Quality Assurance practices related to the structural concrete phase on three fossil fuel power plant projects which are (or have been) under construction in the United States in the past ten years. This analysis identified the response of each Quality Assurance program to criteria similar to those which apply on nuclear power plant projects. The major emphasis was placed on the construction aspects of the structural concrete phase of each project. The engineering and design aspects were examined whenever they interfaced with the construction aspects. For those aspects of the Quality Assurance system which can be considered managerial in nature (i.e., organizational relationships, types of Quality Assurance programs, corrective action procedures, etc.) an attempt has been made to present the alternative approaches that were identified. For those aspects of the Quality Assurance system which are technical in nature (i.e., the frequency of testing for slump, compressive strength, etc.) an attempt has been made to present a comparative analysis between projects and in relation to the recommended or mandated practices presented in the appropriate industry codes and standards.

  1. Crystal Structure of Ethanolamine 5-Nitrosalicylic Acid Organic Adduct

    Institute of Scientific and Technical Information of China (English)

    金轶; 车云霞; 魏荣敏; 郑吉民

    2004-01-01

    The title adduct (C18H24N4O12, Mr = 488.41) crystallizes in monoclinic, space group P21/c with a = 4.0514(19), b = 25.193(11), c = 10.751(5)(A), β = 95.070(8)o, V = 1093.0(9)(A)3, Z = 4, Dc = 1.484 g/cm3, F(000) = 512, μ(MoKα) = 1.26 cm-1, T = 293 K, the final R = 0.0593 and wR = 0.0862 for 956 observed reflections with I > 2(I). The compound is a 1:1 adduct of ethanolamine and 5-nitrosalicylic acid. The nitrogen atom of ethanolamine is protonated. In this crystal there exist a number of hydrogen bonds which link the ethanolamine and 5-nitrosalicylic acid molecules to form a three-dimensional infinite network structure.

  2. Synthesis and Crystal Structure of N-Ferrocenesulfonyl Hexahydropyridine

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The title compound (C15H19FeNO2S, Mr = 333.22) was synthesized by the re- action of ferrocenesulfonyl chloride with hexahydropyridine, and characterized by 1H NMR, IR and elemental analysis. The crystal belongs to monoclinic, space group P21/n with a = 6.0472(5), b = 20.4897(6), c = 11.6584(8)(A), β = 91.3120(10)°, V = 1444.16(16)(A)3, Z = 4, Dc = 1.533 g/cm3, F(000) = 696, μ = 1.188 mm-1, the final R = 0.0309 and wR = 0.0736 for 2057 observed reflection with I > 2σ(I). The structure analysis demonstrates that two cyclopentadienyl rings are almost parallel with a dihedral angle of 1.70o, and hexahydropyridine moiety exists in a chair conformation. Bioassay indicates that the title compound has a good fungicidal activity.

  3. Synthesis and crystal structure of ethyl benzimidazole-2-yl phosphonate

    Institute of Scientific and Technical Information of China (English)

    HU, Fang-Zhong; WENG, Lin-Hong; YANG, Hua-Zheng; ZOU, Xiao-Mao

    2000-01-01

    When N-cyanoimido- ( O, O-diethyl ) phosphonyl/ S-methyl thiocarbonate (1) was treated with o-phenylenediamine in the presence of Et3N in ethanol, diethyl benzimidazole-2-yl recrys phonate(2) was obtained and hydrolyzed during the recrys tallization in MeOH/H2O, generating ethyl benzimidazole-2-yl phosphonate(3). The crystal structure of compound 3 was determined by X-ray diffraction method. The crystals belong to monoclinic, space rgoup C2/c, a=1.78408(18), b=O. 83725(9), c=1.67401(18) nm, β= 118.997(2)°, v=2. 1870(4) nm3, z=8, Dc=1.374g/cm3, F(000)=944.The final R and wR are 0.0499 and 0.1436, respectively. The mechanism of the above reaction is also discussed.

  4. Final Project Report: Development of Micro-Structural Mitigation Strategies for PEM Fuel Cells: Morphological Simulations and Experimental Approaches

    Energy Technology Data Exchange (ETDEWEB)

    Wessel, Silvia [Ballard Materials Products; Harvey, David [Ballard Materials Products

    2013-06-28

    The durability of PEM fuel cells is a primary requirement for large scale commercialization of these power systems in transportation and stationary market applications that target operational lifetimes of 5,000 hours and 40,000 hours by 2015, respectively. Key degradation modes contributing to fuel cell lifetime limitations have been largely associated with the platinum-based cathode catalyst layer. Furthermore, as fuel cells are driven to low cost materials and lower catalyst loadings in order to meet the cost targets for commercialization, the catalyst durability has become even more important. While over the past few years significant progress has been made in identifying the underlying causes of fuel cell degradation and key parameters that greatly influence the degradation rates, many gaps with respect to knowledge of the driving mechanisms still exist; in particular, the acceleration of the mechanisms due to different structural compositions and under different fuel cell conditions remains an area not well understood. The focus of this project was to address catalyst durability by using a dual path approach that coupled an extensive range of experimental analysis and testing with a multi-scale modeling approach. With this, the major technical areas/issues of catalyst and catalyst layer performance and durability that were addressed are: 1. Catalyst and catalyst layer degradation mechanisms (Pt dissolution, agglomeration, Pt loss, e.g. Pt in the membrane, carbon oxidation and/or corrosion). a. Driving force for the different degradation mechanisms. b. Relationships between MEA performance, catalyst and catalyst layer degradation and operational conditions, catalyst layer composition, and structure. 2. Materials properties a. Changes in catalyst, catalyst layer, and MEA materials properties due to degradation. 3. Catalyst performance a. Relationships between catalyst structural changes and performance. b. Stability of the three-phase boundary and its effect on

  5. NASA-UVA Light Aerospace Alloy and Structure Technology Program Supplement: Aluminum-Based Materials for High Speed Aircraft. Final report, 1 December 1991-31 March 1996

    Energy Technology Data Exchange (ETDEWEB)

    Starke, E.A. Jr.

    1996-05-01

    This is the final report of the study `Aluminum-Based Materials for high Speed Aircraft` which had the objectives (1) to identify the most promising aluminum-based materials with respect to major structural use on the HSCT and to further develop those materials and (2) to assess the materials through detailed trade and evaluation studies with respect to their structural efficiency on the HSCT. The research team consisted of ALCOA, Allied-Signal, Boeing, McDonnell Douglas, Reynolds Metals and the University of Virginia. Four classes of aluminum alloys were investigated: (1) I/M 2XXX containing Li and I/M 2XXX with Li, (2) I/M 6XXX, (3) two P/M 2XXX alloys and (4) two different aluminum-based metal matrix composites (MMC). The I/M alloys were targeted for a Mach 2.0 aircraft and the P/M and MMC alloys were targeted for a Mach 2.4 aircraft. Design studies were conducted using several different concepts including skin/stiffener (baseline), honeycomb sandwich, integrally stiffened and hybrid adaptations (conventionally stiffened thin-sandwich skins). Alloy development included fundamental studies of coarsening behavior, the effect of stress on nucleation and growth of precipitates, and fracture toughness as a function of temperature were an integral part of this program. The details of all phases of the research are described in this final report.

  6. Final Project Report: Development of Micro-Structural Mitigation Strategies for PEM Fuel Cells: Morphological Simulations and Experimental Approaches

    Energy Technology Data Exchange (ETDEWEB)

    Wessel, Silvia [Ballard Materials Products; Harvey, David [Ballard Materials Products

    2013-06-28

    The durability of PEM fuel cells is a primary requirement for large scale commercialization of these power systems in transportation and stationary market applications that target operational lifetimes of 5,000 hours and 40,000 hours by 2015, respectively. Key degradation modes contributing to fuel cell lifetime limitations have been largely associated with the platinum-based cathode catalyst layer. Furthermore, as fuel cells are driven to low cost materials and lower catalyst loadings in order to meet the cost targets for commercialization, the catalyst durability has become even more important. While over the past few years significant progress has been made in identifying the underlying causes of fuel cell degradation and key parameters that greatly influence the degradation rates, many gaps with respect to knowledge of the driving mechanisms still exist; in particular, the acceleration of the mechanisms due to different structural compositions and under different fuel cell conditions remains an area not well understood. The focus of this project was to address catalyst durability by using a dual path approach that coupled an extensive range of experimental analysis and testing with a multi-scale modeling approach. With this, the major technical areas/issues of catalyst and catalyst layer performance and durability that were addressed are: 1. Catalyst and catalyst layer degradation mechanisms (Pt dissolution, agglomeration, Pt loss, e.g. Pt in the membrane, carbon oxidation and/or corrosion). a. Driving force for the different degradation mechanisms. b. Relationships between MEA performance, catalyst and catalyst layer degradation and operational conditions, catalyst layer composition, and structure. 2. Materials properties a. Changes in catalyst, catalyst layer, and MEA materials properties due to degradation. 3. Catalyst performance a. Relationships between catalyst structural changes and performance. b. Stability of the three-phase boundary and its effect on

  7. Influence of changing particle structure on the rate of gas-solid gasification reactions. Final report, July 1981-March 1984

    Energy Technology Data Exchange (ETDEWEB)

    1984-04-04

    The objetive of this work is to determine the changes in the particle structure of coal as it undergoes the carbon/carbon dioxide reaction (C + CO/sub 2/ ..-->.. 2CO). Char was produced by heating the coal at a rate of 25/sup 0/C/min to the reaction temperatures of 800/sup 0/C, 900/sup 0/C, 1000/sup 0/C and 1100/sup 0/C. The changes in surface area and effective diffusivity as a result of devolitization were determined. Changes in effective diffusivity and surface area as a function of conversion have been measured for reactions conducted at 800, 900, 1000 and 1100/sup 0/C for Wyodak coal char. The surface areas exhibit a maximum as a function of conversion in all cases. For the reaction at 1000/sup 0/C the maximum in surface area is greater than the maxima determined at all other reaction temperatures. Thermogravimetric rate data were obtained for five coal chars; Wyodak, Wilcox, Cimmeron, Illinois number 6 and Pittsburgh number 6 over the temperature range 800-1100/sup 0/C. All coal chars exhibit a maximum in reaction rate. Five different models for gas-solid reactions were evaluated. The Bhatia/Perlmutter model seems to best represent the data. 129 references, 67 figures, 37 tables.

  8. FINAL TECHNICAL REPORT Synthetic, Structural and Mechanistic Investigations of Olefin Polymerization Catalyzed by Early Transition Metal Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Bercaw, John E. [California Institute of Technology

    2014-05-23

    The goal of this project is to develop new catalysts and provide understanding of ligand effects on catalyst composition in order to guide development of superior catalyst systems for polymerization of olefins. Our group is designing and synthesizing new “LX2”,“pincer” type ligands and complexing early transition metals to afford precatalysts. In a collaboration with Hans Brintzinger from the University of Konstanz, we are also examining the structures of the components of catalyst systems obtained from reaction of zirconocene dichlorides with aluminum alkyls and aluminum hydrides. Such systems are currently used commercially to produce polyolefins, but the nature of the active and dormant species as well as the mechanisms of their interconversions are not understood. New information on catalyst design and performance may lead to new types of polymers and/or new chemical transformations between hydrocarbons and transition metal centers, ultimately contributing to the development of catalytic reactions for the production of fuels, commodity and polymeric materials.

  9. Applications of the diffraction technique in solid state chemistry from "ab-initio" structure solution to final structure refinement: powder and single crystal

    OpenAIRE

    Napolitano, Emilio

    2011-01-01

    Establishing the crystal structure in solid state chemistry is often a pre-requisite for understanding and predicting the function and technological properties of the matter. The single crystal and powder diffraction approaches play a fundamental role to achieve this goal. These two methods are non-destructive analytical techniques which provide detailed information about the internal lattice of crystalline substances, unit cell dimensions, bond-lengths, bond-angles, and details of site-or...

  10. Syntheses and Structures of Two New Coordination Polymers:[Cu(C14H9O4)(C14H10O4)(C12H12N2)2] and [Ag(C14H9O4)(C13H14N2)]·0.5 H2O

    Institute of Scientific and Technical Information of China (English)

    傅志勇; 胡胜民; 杜文新; 张建军; 项生昌; 吴新涛

    2004-01-01

    Under hydrothermal conditions, two new ribbon-like structures, [Cu(C14H9O4)-analysis revealed that these structures were constructed by mixed ligands. The coordination polymer forms the basic architecture while the weak interactions extend the framework into a secondary structure. The whole structures of them are governed by collaboration of the strong and weak interactions. Compound 1 crystallizes in monoclinic, space group C2/c with a = 17.0485(3), b =1 1.0558(3), c = 22.7623(4) A, β = 102.465(1)°, V = 4189.2(2) A3, Z = 4, Mr = 915.44, Dc = 1.451g/mL, F(000) = 1900 andμ(MoKα) = 0.587 cm-1. The final R and wR are 0.0030 and 0.1022,respectively for 3037 observed reflections with I > 2σ(I). Compound 2 crystallizes in monoclinic,space group P21/c with a = 11.5963(4), b = 11.7004(5), c = 17.1254(5) A,β = 95.620(1)°, V =2312.4(1) A3, Z = 4, Mr = 556.35, Dc = 1.598 g/mL, F(000) = 1132 andμ(MoKα) = 0.912 cm-1The final R and wR are 0.0431 and 0.1050, respectively for 2629 observed reflections with I > 2σ(I).

  11. Construction and installation of low-cost energy-conservation devices on existing residential structures. Final report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1983-01-01

    Through the Neighborhood Housing Services, Incorporated of Charlotte, a series of hands-on workshops and a demonstration site was provided to enable residents of the Plaza-Midwood Neighborhood to build and install a variety of low-cost, durable, small scale, energy conservation systems. This experimental approach enabled homeowners to apply specific technologies to their own homes. These cost effective measures were designed to encourage both self reliance and the use of renewable resources. The weekend projects included protected entry, numerous moveable window insulation devices, solar air collector/greenhouse, window greenhouse and water storage tubes. The building used for retrofit was the office for the Neighborhood Housing Services (NHS), a non-profit corporation formed to help revitalize residential structures and maintain the economic, racial, and social character of existing neighborhoods. The particular neighborhood involved was Plaza-Midwood and covers approximately a 2 square mile area. The neighborhood housing stock is of the 1910 to 1940 variety with the predominate architectual style being bungalow frame, having 1000 to 1900 square feet in area. The neighborhood is a racially integrated one, with about 70% of the residents being homeowners. An estimated 1700 housing units are in this area. The NHS office presently serves as a resource center for area residents who need loans and/or construction assistance. Providing a continuing educational program is a function of this organization. The Grant provided a significant contribution as a resource for energy conservation mined residents. A resource room displaying procedures and diagrams for the various projects in this proposal was established. Additional resource literature was provided and used by local residents.

  12. 4-wave mixing for phase-matching free nonlinear optics in quantum cascade structures : LDRD 08-0346 final report.

    Energy Technology Data Exchange (ETDEWEB)

    Chow, Weng Wah; Wanke, Michael Clement; Allen, Dan G.; Yang, Zhenshan; Waldmueller, Ines

    2010-10-01

    Optical nonlinearities and quantum coherences have the potential to enable efficient, high-temperature generation of coherent THz radiation. This LDRD proposal involves the exploration of the underlying physics using intersubband transitions in a quantum cascade structure. Success in the device physics aspect will give Sandia the state-of-the-art technology for high-temperature THz quantum cascade lasers. These lasers are useful for imaging and spectroscopy in medicine and national defense. Success may have other far-reaching consequences. Results from the in-depth study of coherences, dephasing and dynamics will eventually impact the fields of quantum computing, optical communication and cryptology, especially if we are successful in demonstrating entangled photons or slow light. An even farther reaching development is if we can show that the QC nanostructure, with its discrete atom-like intersubband resonances, can replace the atom in quantum optics experiments. Having such an 'artificial atom' will greatly improve flexibility and preciseness in experiments, thereby enhancing the discovery of new physics. This is because we will no longer be constrained by what natural can provide. Rather, one will be able to tailor transition energies and optical matrix elements to enhance the physics of interest. This report summarizes a 3-year LDRD program at Sandia National Laboratories exploring optical nonlinearities in intersubband devices. Experimental and theoretical investigations were made to develop a fundamental understanding of light-matter interaction in a semiconductor system and to explore how this understanding can be used to develop mid-IR to THz emitters and nonclassical light sources.

  13. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Gurney, Kevin R

    2015-01-12

    This document constitutes the final report under DOE grant DE-FG-08ER64649. The organization of this document is as follows: first, I will review the original scope of the proposed research. Second, I will present the current draft of a paper nearing submission to Nature Climate Change on the initial results of this funded effort. Finally, I will present the last phase of the research under this grant which has supported a Ph.D. student. To that end, I will present the graduate student’s proposed research, a portion of which is completed and reflected in the paper nearing submission. This final work phase will be completed in the next 12 months. This final workphase will likely result in 1-2 additional publications and we consider the results (as exemplified by the current paper) high quality. The continuing results will acknowledge the funding provided by DOE grant DE-FG-08ER64649.

  14. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    DeTar, Carleton [P.I.

    2012-12-10

    This document constitutes the Final Report for award DE-FC02-06ER41446 as required by the Office of Science. It summarizes accomplishments and provides copies of scientific publications with significant contribution from this award.

  15. Monoclinic-to-orthorhombic phase transition of the hexamethylenetetramine-2-methylbenzoic acid (1/2) cocrystal with temperature-dependent dynamic molecular disorder.

    Science.gov (United States)

    Chia, Tze Shyang; Quah, Ching Kheng

    2016-12-01

    As a function of temperature, the hexamethylenetetramine-2-methylbenzoic acid (1/2) cocrystal, C6H12N4·2C8H8O2, undergoes a reversible structural phase transition. The orthorhombic high-temperature phase in the space group Pccn has been studied in the temperature range between 165 and 300 K. At 164 K, a t2 phase transition to the monoclinic subgroup P21/c space group occurs; the resulting twinned low-temperature phase was investigated in the temperature range between 164 and 100 K. The domains in the pseudomerohedral twin are related by a twofold rotation corresponding to the matrix (100/0-10/00-1. Systematic absence violations represent a sensitive criterium for the decision about the correct space-group assignment at each temperature. The fractional volume contributions of the minor twin domain in the low-temperature phase increases in the order 0.259 (2) → 0.318 (2) → 0.336 (2) → 0.341 (3) as the temperature increases in the order 150 → 160 → 163 → 164 K. The transformation occurs between the nonpolar point group mmm and the nonpolar point group 2/m, and corresponds to a ferroelastic transition or to a t2 structural phase transition. The asymmetric unit of the low-temperature phase consists of two hexamethylenetetramine molecules and four molecules of 2-methylbenzoic acid; it is smaller by a factor of 2 in the high-temperature phase and contains two half molecules of hexamethylenetetramine, which sit across twofold axes, and two molecules of the organic acid. In both phases, the hexamethylenetetramine residue and two benzoic acid molecules form a three-molecule aggregate; the low-temperature phase contains two of these aggregates in general positions, whereas they are situated on a crystallographic twofold axis in the high-temperature phase. In both phases, one of these three-molecule aggregates is disordered. For this disordered unit, the ratio between the major and minor conformer increases upon cooling from

  16. Orthorhombic polymorph of ErP{sub 5}O{sub 14}, crystal structure and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Katrusiak, A. [Uniwersytet Adama Mickiewicza, Poznan (Poland); Kaczmarek, F. [Uniwersytet Adama Mickiewicza, Poznan (Poland)

    1995-08-01

    Erbium pentaphosphate crystals have been characterized and the structure of the orthorhombic polymorph (type III) determined by X-rays. It has been found that the orthorhombic samples of ErP{sub 5}O{sub 14}, space group Pnma, crystallize mainly at higher temperatures and usually are much larger than monoclinic crystals, space group C2/c, obtained from lower-temperature crystallizations. Differences in fluorescence and upconversion properties between orthorhombic and monoclinic polymorphs have been detected. (orig.)

  17. Molecular structure of a new chlorinated disinfection by-product in drinking water

    Science.gov (United States)

    Gong, Huijuan; Wang, Huaqin; You, Zhen; Zou, Huixian; Shen, Xing

    2005-06-01

    A new found chlorinated disinfection by-product (DBP) in drinking water was isolated and characterized by MS, FTIR, 1H and 13C NMR spectroscopy. Single crystal X-ray diffraction method was also carried out to determinate the exact structure of the compound. The crystal is of monoclinic, and space group P2 1/ m with a=7.8800(16), b=6.7950(14), c=8.8350(18) Å, β=115.02(3)°, V=428.67(15) Å 3, Z=4, Dc=1.778 g/cm 3, μ=1.028 mm -1 and F(000)=228, R=0.0510 and wR=0.2205 for 982 unique reflections with 918 observed ones [ I>2 σ( I)]. The results confirmed the structure of this compound. It was finally identified as 2,2,4-trichloro-5-methoxy-cyclopent-4-ene-1,3-dione (TCMCD).

  18. M(o)ssbauer spectroscopic study of monoclinic astrophyllite%单斜星叶石矿物的穆斯堡尔光谱学研究

    Institute of Scientific and Technical Information of China (English)

    苏文; 施倪承; 刘密兰; 马喆生; 李哲; Alexandr KHOMYAKOV

    2008-01-01

    Monoclinic astrophyllite from Kala Peninsula, Russia was investigated by 57Fe Mossbauer effect. The Mossbauer spectra of the sample at 298 K, 180 K and 80 K were measured. Each spectrum of monoclinic astrophyllite consists of two Fe2+ and one Fe3+ quadrupole doublets. The distortion parameters, the variances of the octahedral bond angles 0-2 and the normalized bond-length variation △ for monoclinic astrophyllite were calculated. However, since a discrepancy between two distortion parameters exists, an assignment of the quadrupole doublet to iron at the specific site was not given. Temperature dependences of the isomer shift and the quadrupole splitting were presented and discussed. According to the ratio of ferric to total iron obtained by the Mossbauer effect and the mean value off ( Fe3+ (O) )/f ( Fe2+ (O) ), the chemical formula of monoclinic astrophyllite was rewritten.%本文对产于俄罗斯希宾地区的单斜星叶石进行了不同的温度条件下的穆斯堡尔光谱效应研究.通过在温度分别在298 K,180 K和80 K条件下的分析,发现单斜星叶石由2个Fe2+和1个Fe3+四极双峰组成,并进行了单斜星叶石中的畸变参数包括八面体键角(σ2)和键长变量(△)的计算.但是,在两个畸变参数之间存在着明显的差异,将无法对它们的穆斯堡尔参数和四极双峰进行指派.本文对温度在同质异能位移和四极分裂中的作用进行了探讨,根据通过穆斯堡尔效应和f(Fe3+(O))/f(Fe2+(O))的平均值获得的三价铁对全铁的比值,改写了单斜星叶石的化学式.

  19. The monoclinic form of 2,9-dichloro-5,12-dihydroquino[2,3-b] acridine-7,14-dithione dimethylacetamide disolvate

    OpenAIRE

    Hoki, T.; Senju, T.; Mizuguchi, Jin

    2005-01-01

    The title compound, C(20)H(10)Cl(2)N(2)S(2)(.)2C(4)H(9)NO, is a dimethylacetamide (DMA) disolvate of DTQ-Cl, which is a thionated derivative of a 2,9-dichloroquinacridone pigment. The compound shows polymorphism and this paper reports the monoclinic form ( space group P2(1)/c, Z = 4). Two DMA molecules are hydrogen bonded via their O atoms to the NH group of DTQ-Cl. The molecular planes of the two DMA molecules are asymmetrically twisted with respect to the DTQ-Cl skeleton by 11.65 (8) and 31...

  20. Schedulability Analysis for Java Finalizers

    DEFF Research Database (Denmark)

    Bøgholm, Thomas; Hansen, Rene Rydhof; Ravn, Anders P.;

    2010-01-01

    Java finalizers perform clean-up and finalisation of objects at garbage collection time. In real-time Java profiles the use of finalizers is either discouraged (RTSJ, Ravenscar Java) or even disallowed (JSR-302), mainly because of the unpredictability of finalizers and in particular their impact ...... programs. Finally, we extend the SARTS tool for automated schedulability analysis of Java bytecode programs to handle finalizers in a fully automated way.......Java finalizers perform clean-up and finalisation of objects at garbage collection time. In real-time Java profiles the use of finalizers is either discouraged (RTSJ, Ravenscar Java) or even disallowed (JSR-302), mainly because of the unpredictability of finalizers and in particular their impact...... on the schedulability analysis. In this paper we show that a controlled scoped memory model results in a structured and predictable execution of finalizers, more reminiscent of C++ destructors than Java finalizers. Furthermore, we incorporate finalizers into a (conservative) schedulability analysis for Predictable Java...

  1. Comparative X-ray diffraction study of the crystalline microstructure of tetragonal and monoclinic vanadium-zirconium dioxide solid solutions produced from gel precursors

    Energy Technology Data Exchange (ETDEWEB)

    Kojdecki, Marek Andrzej [Wojskowa Akademia Techniczna, Warszawa (Poland). Inst. Matematyki i Kryptologii; Ruiz de Sola, Esther; Alarcon, Javier [Valencia Univ., Burjasot (Spain). Dept. de Quimica Inorganica; Serrano, Francisco Javier; Amigo, Jose Maria [Valencia Univ., Burjasot (Spain). Dept. de Geologia

    2009-04-15

    The microstructural characteristics of solid solutions, prepared by heating dried gel precursors with nominal compositions V{sub x}Zr{sub 1-x}O{sub 2} (0{<=}x{<=}0.1) at 723 and 1573 K, were determined from X-ray diffraction patterns. The crystalline microstructure of the resulting specimens, characterized by a prevalent crystallite shape, a volume-weighted crystallite size distribution and a second-order lattice strain distribution, was found to depend on the vanadium content. A characteristic feature of all size distributions was their bimodality, explained as a result of transformations between tetragonal and monoclinic phases during thermal treatment. A comparative study of the microstructure of both zirconia phases has been carried out, enabling reconstruction of a probable course of crystallization of both pure and vanadium-doped zirconias: on heating a sample, nucleation and the early growth stages involve crystallites of both phases; then on annealing and cooling, the crystallites of one phase transform into the other, depending on the thermal treatment temperature. Each logarithmic normal component of the crystallite size distribution of the resulting phase can be attributed to one of these processes. The limit of solubility of vanadium in tetragonal and monoclinic zirconia is estimated from the microstructural characteristics. (orig.)

  2. A novel monoclinic phase of impurity-doped CaGa2S4 as a phosphor with high emission intensity

    Directory of Open Access Journals (Sweden)

    Akihiro Suzuki

    2012-06-01

    Full Text Available In the solid-state synthesis of impurity-doped CaGa2S4, calcium tetrathiodigallate(III, a novel phosphor material (denominated as the X-phase, with monoclinic symmetry in the space group P21/a, has been discovered. Its emission intensity is higher than that of the known orthorhombic polymorph of CaGa2S4 crystallizing in the space group Fddd. The asymmetric unit of the monoclinic phase consists of two Ca, four Ga and eight S sites. Each of the Ca and Ga atoms is surrounded by seven and four sulfide ions, respectively, thereby sharing each of the sulfur sites with the nearest neighbours. In contrast, the corresponding sites in the orthorhombic phase are surrounded by eight and four S atoms, respectively. The photoluminescence peaks from Mn2+ and Ce3+ in the doped X-phase, both of which are supposed to replace Ca2+ ions, have been observed to shift towards the high energy side in comparison with those in the orthorhombic phase. This suggests that the crystal field around the Mn2+ and Ce3+ ions in the X-phase is weaker than that in the orthorhombic phase.

  3. Final Report

    DEFF Research Database (Denmark)

    Heiselberg, Per; Brohus, Henrik; Nielsen, Peter V.

    This final report for the Hybrid Ventilation Centre at Aalborg University describes the activities and research achievement in the project period from August 2001 to August 2006. The report summarises the work performed and the results achieved with reference to articles and reports published...

  4. A first principles study of structural stability, electronic structure and mechanical properties of ABeH{sub 3} (A = Li, Na)

    Energy Technology Data Exchange (ETDEWEB)

    Santhosh, M.; Rajeswarapalanichamy, R.; Priyanga, G. Sudha; Murugan, A. [Department of Physics, N.M.S.S.V.N college, Madurai, Tamilnadu-625019 (India); Kanagaprabha, S. [Department of Physics, Kamaraj College, Tuticorin, Tamil Nadu 628 003 (India); Iyakutti, K. [Department of physics and Nanotechnology, SRM University, Chennai, Tamilnadu-603203 (India)

    2015-06-24

    Ab initio calculations are performed to investigate the structural stability, electronic structure and mechanical properties of ABeH{sub 3} (A = Li, Na) for three different crystal structures, namely orthorhombic (Pnma), monoclinic (P2{sub 1}/c) and triclinic (P-1) phase. Among the considered structures monoclinic (P2{sub 1}/c) phase is found to be the most stable one for all the three hydrides at ambient condition. The electronic structure reveals that these materials are wide band gap semiconductors. The calculated elastic constants indicate that these materials are mechanically stable at ambient condition.

  5. Lewis-base Adducts of Lead(Ⅱ) Compounds: Synthesis, Structure and Quantum Chemistry Calculation of Mononuclear Pb(phen)(SCN)2

    Institute of Scientific and Technical Information of China (English)

    李浩宏; 陈之荣; 李俊篯; 黄长沧; 赵斌; 倪朝霞

    2005-01-01

    The lead thiocyanate adduct Pb(phen)(SCN)2 (phen = 1,10-phenanthroline) has been prepared by a direct synthetic method and structurally characterized. It presents a mononuclear structure and crystallizes in monoclinic, space group C2/c with a = 17.505(4), b = 13.383(3), c = 6.7916(14) (A), β = 112.25(3)o, V = 1472.6(6) (A)3, Z = 4, Dc = 2.271 g/cm3, μ(MoKα) = 11.737 mm-1, F(000) = 936, C14H8N4PbS2, Mr = 503.58, the final R = 0.0446 and wR = 0.1034 for 1601 observed reflections with I > 2σ(I). Structure analysis showed that the lead atom presents an unusual four- coordination geometry with a large vacancy, possibly indicating the stereochemical activity of 6s2 lone pair electrons.

  6. Synthesis and Crystal Structure of Cis-syn Cyclobutane 1-(Carboxyethyl)thymine Dimer Monopentyl Amide Monotryptophan Methyl Ester Amide

    Institute of Scientific and Technical Information of China (English)

    TANG Wen-Jian; SONG Hai-Bin; SONG Qin-Hua

    2007-01-01

    The crystal structure of the title compound (C34H47N7O9, Mr=697.79) has been determined by single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21 with a=9.000(8), b=11.360(10), c=17.841(15)(A), β=97.083(14)°, V=1810(3) (A)3, Z=2, F(000)=744, Dc=1.280 g/cm3, μ=0.094 mm-1, the final R=0.0721 and wR=0.1942 for 2479 observed reflections with Ⅰ > 2σ(Ⅰ). The two methyl groups attached to the cyclobutane ring are cis oriented. An intramolecular hydrogen bond (N(6)-H(6)…O(8)) (A)ntroduces rigidity into the title molecule and the crystal structure is stabilized by intermolecular N-H…O hydrogen bonds.

  7. Synthesis and Crystal Structure of N'-(4-fluorobenzylidene)-2-(1H-1,2,4-triazole-1-yl) acetohydrazide

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    N'-(4-fluorobenzylidene)-2-(1H-1,2,4-triazole-1-yl)acetohydrazide was synthesized by the reaction of 4-fluorobenzaldehyde with 2-(1H-1,2,4-triazole-1-yl) acetohydrazide. The structure was confirmed via elemental analysis, MS,1H NMR, IR, and X-ray diffraction. It crystallized in a monoclinic system with space group P2 ( 1 ), a =0.4905(1) nm, b=0.8160(2) nm, c=1.4105(3) nm,β=93.33(3)°,Z=2, V=0.5636(2) nm3, Dc =1.457 Mg/m3,μ=0.112 mm-1 , F(000) =256, and final R1 =0. 0685. Several intermolecular hydrogen-bond interactions existed in the crystal structure, facilitating the stabilization of the compound.

  8. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Stinis, Panos [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-08-07

    This is the final report for the work conducted at the University of Minnesota (during the period 12/01/12-09/18/14) by PI Panos Stinis as part of the "Collaboratory on Mathematics for Mesoscopic Modeling of Materials" (CM4). CM4 is a multi-institution DOE-funded project whose aim is to conduct basic and applied research in the emerging field of mesoscopic modeling of materials.

  9. Attitudes towards a final repository for the spent nuclear fuel. Structure and causes; Attityd till slutfoervar av anvaent kaernbraensle. Struktur och orsaker

    Energy Technology Data Exchange (ETDEWEB)

    Sjoeberg, Lennart (Stockholm School of Economics (Sweden). Center for Risk Research)

    2008-09-15

    This report presents the results of a questionnaire survey of attitudes towards a final repository for the spent nuclear fuel. The questionnaire was mailed to 3,000 persons. Participants were young and older people in Oskarshamn municipality and Oesthammar municipality as well as in the rest of the country. Fifty-one percent responded. The questionnaire included a large number of questions of possible relevance for understanding the structure of and reasons for the person's attitude towards a final repository. Questions concerning nuclear power were dealt with in a special section. Men were more positively disposed towards a repository than women, older people more than young. The gender differences are mainly attributable to the variation in attitude towards nuclear power and concern about nuclear accidents. In the case of older people, interest was also a factor. Young people were not as interested in the issue. The most important factor in determining the attitude towards a final repository was the benefit it was expected to bring to the municipality. Moral and emotional aspects were also important. Risk played a relatively subordinate role. Social aspects were very important: those who frequently spoke with people who were positively disposed tended to be positive themselves, and vice versa for those who were negative. This factor could explain some of the gender differences in attitude. Attitudes in Oskarshamn were slightly more positive than in Oesthammar, probably due to the fact that the residents in Oskarshamn had a greater sense of participation in the municipality's decision in the matter. Information from SKB was also found to be an important factor for the differences in attitude between the municipalities. Eight percentage points more people had received information in Oskarshamn than in Oesthammar. The difference may be small, but it exists and does appear to be of some importance. Attitudes in Oskarshamn and Oesthammar continued to be much

  10. Solidification Structure and Macrosegregation of Billet Continuous Casting Process with Dual Electromagnetic Stirrings in Mold and Final Stage of Solidification: A Numerical Study

    Science.gov (United States)

    Jiang, D.; Zhu, M.

    2016-08-01

    Coupling macroscale heat transfer and fluid flow with microscale grain nucleation and crystal growth, a mixed columnar-equiaxed solidification model was established to study the SWRT82B steel solidification structure and macrosegregation in 160 mm × 160 mm billet continuous casting with dual electromagnetic stirrings in mold and final stage of solidification (M-EMS and F-EMS). In the model, the phases of liquid, columnar, and equiaxed were treated separately and the initial growing equiaxed phase, which could move freely with liquid, was regarded as slurry. To obtain the equiaxed grains nucleation and columnar front evolution, the unit tracking method and the columnar front tracking model were built. The model was validated by magnetic induction intensity of stirrer, billet surface temperature, and carbon segregation. The equiaxed phase evolution and the solute transport with effect of fluid flow and grains transport were described in this article. The results show that the equiaxed phase ratio will not increase obviously with higher current intensity of M-EMS, while the negative segregation near the strand surface becomes more serious. The negative segregation zone near the billet center and the center positive segregation come into being with the effect of equiaxed grains sedimentation and liquid thermosolutal flow. It is also found that the liquid solute transport in the F-EMS zone becomes the main factor with higher current intensity rather than the solidification rate, and therefore, the final billet center segregation decreases first and then turns to rise with the current intensity. The optimal current intensities of M-EMS and F-EMS proposed for SWRT82B billet continuous casting are 200 and 400 A, respectively.

  11. Solidification Structure and Macrosegregation of Billet Continuous Casting Process with Dual Electromagnetic Stirrings in Mold and Final Stage of Solidification: A Numerical Study

    Science.gov (United States)

    Jiang, D.; Zhu, M.

    2016-12-01

    Coupling macroscale heat transfer and fluid flow with microscale grain nucleation and crystal growth, a mixed columnar-equiaxed solidification model was established to study the SWRT82B steel solidification structure and macrosegregation in 160 mm × 160 mm billet continuous casting with dual electromagnetic stirrings in mold and final stage of solidification (M-EMS and F-EMS). In the model, the phases of liquid, columnar, and equiaxed were treated separately and the initial growing equiaxed phase, which could move freely with liquid, was regarded as slurry. To obtain the equiaxed grains nucleation and columnar front evolution, the unit tracking method and the columnar front tracking model were built. The model was validated by magnetic induction intensity of stirrer, billet surface temperature, and carbon segregation. The equiaxed phase evolution and the solute transport with effect of fluid flow and grains transport were described in this article. The results show that the equiaxed phase ratio will not increase obviously with higher current intensity of M-EMS, while the negative segregation near the strand surface becomes more serious. The negative segregation zone near the billet center and the center positive segregation come into being with the effect of equiaxed grains sedimentation and liquid thermosolutal flow. It is also found that the liquid solute transport in the F-EMS zone becomes the main factor with higher current intensity rather than the solidification rate, and therefore, the final billet center segregation decreases first and then turns to rise with the current intensity. The optimal current intensities of M-EMS and F-EMS proposed for SWRT82B billet continuous casting are 200 and 400 A, respectively.

  12. Crystal Structure of a Nickel(Ⅱ) Complex with Asymmetric L-Histidine Ligand

    Institute of Scientific and Technical Information of China (English)

    JIN Yi; CHE Yun-Xia; ZHENG Ji-Min

    2006-01-01

    A novel nickel(Ⅱ) complex with L-histidine has been synthesized and solved by single-crystal X-ray diffraction analysis at physiological pH. The title complex (C7H16NiN4O6S, Mr= 343.01) crystallizes in monoclinic, space group P21 with a = 7.2194(7), b = 7.5968(7), c =12.2797(11) (A), β = 93.3110(10)°, V = 672.35(11) (A)3, Z = 2, Dc= 1.694 g/cm3, F(000) = 356,μ(MoKα) = 1.626 mm-1, T = 293(2) K, the final R = 0.0184 and wR = 0.0426 for 2207 observed reflections with I > 2σ(Ⅰ). The complex provides insights into a possible structural arrangement between nickel (Ⅱ) and L-histidine which may be physiologically important and abundantly present in biological systems.

  13. Synthesis and Crystal Structure of 2-Amino-4-chloro-5-(4'-methylbenzyl)-6-methylpyrimidine

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The title compound 2-amino-4-chloro-5-(4'-methylbenzyl)-6-methylpyrimidine (C26H28Cl2N6, Mr= 495.44) has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction analysis. The crystal belongs to monoclinic, space group P21/c with a = 14.892(7), b = 6.129(3), c = 14.889(7) (A), β= 109.795(8)°, V= 1278.7(10) (A)3, Z = 2, F(000) = 520, Dc = 1.287 g/cm3, μ= 0.280 mm-1, the final R = 0.0577 and wR = 0.1589 for 1357 observed reflections with Ⅰ>2σ(Ⅰ). A total of 6091 reflections were collected, of which 2257 were independent (Rint = 0.033). The X-ray analysis reveals that the chlorine atom and methyl of the title compound are disordered.

  14. Crystal Structure of Lithium Yttrium Borate LiY6O5(BO3)3

    Institute of Scientific and Technical Information of China (English)

    GAO Jian-Hua

    2006-01-01

    Single crystals of LiY6O5(BO3)3 were obtained by the flux method and its structure was determined by a four-circle automatic diffractometer with a MoKa radiation. It crystallizes in monoclinic, space group P21/n with a = 8.330(3), b = 15.444(4), c = 8.780(3) (A), β = 91.85(3)°, V =1129.0(6) (A)3, Z = 4, Mr= 796.83, F(000) = 1456, μ = 30.567 mm-1, Dc = 4.688 g/cm3, the final R =0.0722 and wR = 0.1304. It exhibits a three-dimensional framework of yttrium-oxygen polyhedra interconnected by common edges and corners. B and Li atoms are located in the planes and cavities formed by oxygen atoms, respectively.

  15. Synthesis and Structure of Bis-(o-vanillin)di-pyridine Nickel(Ⅱ)-pyridine Dihydrate

    Institute of Scientific and Technical Information of China (English)

    孙命; 王瑾玲; 段月琴; 缪方明; 翁林红; 冷雪冰

    2001-01-01

    The structure of the complex bis-(o-vanillin)di-pyridine nickel(Ⅱ)([ Ni X-ray analysis.The crystal data are as follows: Monoclinic,P21/n,a=12.273(1),b=17.4700.674mm-1,F(000)=1328,final R=0.0428,Rw=0.1228 for 4528 observable reflections with I≥2σ(Ⅰ).The Nickel(Ⅱ)atom in the complex has a slightly distorted octahedral coordination geometr y and is six-coordinated by four O atoms from two O-Vanillin ligands and two N atoms from two pyridines.In the crystal,the Ni(Ⅱ)-complex and water molecules are linked through a network of hydrogen bonds.

  16. Synthesis and Crystal Structure of a 3-Arylamino-3-Deoxy Sugar Derivative

    Institute of Scientific and Technical Information of China (English)

    JI Xiao-Ming; SUN He-Ping; MO Juan; LIU Hong-Min

    2006-01-01

    3-Deoxy-3-(p-fluorine-phenylamino)-l,2-O-isopropylidene-α-D-ribofuranose 3 was synthesized and characterized by IR, NMR and HRMS, and its crystal structure was determined by X-ray diffraction analysis. Crystal data for 3: monoclinic, space group P21, a = 7.0403(14), b =6.7780(4), c = 14.932(3) (A), β = 94.74(3)°, C14H18FNO4, Mr = 283.29, V= 710.1(2)(A)3, Z = 2, Dc =1.325 g/cm3, μ=0.105 mm-1, F(000)=300, the final R=0.0468 and wR=0.0926 for 1969observed reflections (I> 2σ(I)). Two intermolecular hydrogen bonds are observed. The absolute configuration of this molecule was confirmed by comparison with that of the original material.

  17. Ab initio electronic band structure study of III-VI layered semiconductors

    Science.gov (United States)

    Olguín, Daniel; Rubio-Ponce, Alberto; Cantarero, Andrés

    2013-08-01

    We present a total energy study of the electronic properties of the rhombohedral γ-InSe, hexagonal ɛ-GaSe, and monoclinic GaTe layered compounds. The calculations have been done using the full potential linear augmented plane wave method, including spin-orbit interaction. The calculated valence bands of the three compounds compare well with angle resolved photoemission measurements and a discussion of the small discrepancies found has been given. The present calculations are also compared with recent and previous band structure calculations available in the literature for the three compounds. Finally, in order to improve the calculated band gap value we have used the recently proposed modified Becke-Johnson correction for the exchange-correlation potential.

  18. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    R Paul Drake

    2004-01-12

    OAK-B135 This is the final report from the project Hydrodynamics by High-Energy-Density Plasma Flow and Hydrodynamics and Radiation Hydrodynamics with Astrophysical Applications. This project supported a group at the University of Michigan in the invention, design, performance, and analysis of experiments using high-energy-density research facilities. The experiments explored compressible nonlinear hydrodynamics, in particular at decelerating interfaces, and the radiation hydrodynamics of strong shock waves. It has application to supernovae, astrophysical jets, shock-cloud interactions, and radiative shock waves.

  19. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Jarillo-Herrero, Pablo [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2017-02-07

    This is the final report of our research program on electronic transport experiments on Topological Insulator (TI) devices, funded by the DOE Office of Basic Energy Sciences. TIbased electronic devices are attractive as platforms for spintronic applications, and for detection of emergent properties such as Majorana excitations , electron-hole condensates , and the topological magneto-electric effect . Most theoretical proposals envision geometries consisting of a planar TI device integrated with materials of distinctly different physical phases (such as ferromagnets and superconductors). Experimental realization of physics tied to the surface states is a challenge due to the ubiquitous presence of bulk carriers in most TI compounds as well as degradation during device fabrication.

  20. Difference in the luminescence properties of orthorhombic and monoclinic forms of Y{sub 2}GeO{sub 5}:Ln (Ln = Tb{sup 3+} and Dy{sup 3+})

    Energy Technology Data Exchange (ETDEWEB)

    Tyagi, Adish; Shah, Alpa; Sudarsan, V., E-mail: vsudar@barc.gov.in; Vatsa, R.K.; Jain, V.K., E-mail: jainvk@barc.gov.in

    2015-04-15

    Highlights: • Improved emission colour purity with orthorhombic form of Y{sub 2}GeO{sub 5}. • Non-stationary quenching exists in orthorhombic and monoclinic forms of Y{sub 2}GeO{sub 5}:Tb. • Ion pair formation and cross relaxation quenching operating for Y{sub 2}GeO{sub 5}:Dy samples. - Abstract: The luminescence properties of Tb{sup 3+} and Dy{sup 3+} doped orthorhombic and monoclinic forms of Y{sub 2}GeO{sub 5} are significantly different. Orthorhombic Y{sub 2}GeO{sub 5} doped with Tb{sup 3+} and Dy{sup 3+} ions gives bright green and blue emission upon UV light excitation with CIE coordinates (0.25, 0.46) and (0.25, 0.24), respectively. The monoclinic Y{sub 2}GeO{sub 5} doped with these ions exhibits light green and yellowish white emissions, respectively. This has been attributed to the differences in crystallographic environments around Y{sup 3+} ions in orthorhombic and monoclinic forms of Y{sub 2}GeO{sub 5}. Quantum yield of emission for orthorhombic Y{sub 2}GeO{sub 5}:Tb (∼29%) is significantly higher than that of the monoclinic Y{sub 2}GeO{sub 5}:Tb (∼14%). Lifetime values corresponding to {sup 4}F{sub 9/2} level of Dy{sup 3+} ions in both monoclinic and orthorhombic forms of Y{sub 2}GeO{sub 5} follow an opposite trend with respect to {sup 5}D{sub 4} level of Tb{sup 3+} ions. This is attributed to difference in the concentration quenching mechanism operating for Tb{sup 3+} and Dy{sup 3+} ions.

  1. Study on optical properties of rare-earth ions in nanocrystalline monoclinic SrAl2O4: Ln (Ln = Ce3+, Pr3+, Tb3+).

    Science.gov (United States)

    Fu, Zuoling; Zhou, Shihong; Zhang, Siyuan

    2005-08-01

    SrAl(2)O(4): Ln (Ln = Ce(3+), Pr(3+), Tb(3+)) nanocrystals have been synthesized by the combustion method. The results of XRD indicated that the resulting SrAl(2)O(4): Ln (Ln = Ce(3+), Pr(3+), Tb(3+)) nanocrystals have a reduced and distorted monoclinic lattice compared with bulk materials. The spectral properties are measured, and it is found that the excitation peaks of 5d energy levels red shift in nanocrystals in contrast to that in bulk crystals. The mechanism of spectra and energy changes is investigated. The order of the degree of red shift for nano SrAl(2)O(4): Ln (Ln = Ce(3+), Pr(3+), Tb(3+)) crystals is Pr(3+) > Ce(3+) > Tb(3+), which is in good agreement with our predicted results.

  2. Phase-controlled synthesis of polymorphic tungsten diphosphide with hybridization of monoclinic and orthorhombic phases as a novel electrocatalyst for efficient hydrogen evolution

    Science.gov (United States)

    Pi, Mingyu; Wu, Tianli; Guo, Weimeng; Wang, Xiaodeng; Zhang, Dingke; Wang, Shuxia; Chen, Shijian

    2017-05-01

    The design and development of high-efficiency and non-noble-metal hydrogen evolution reaction (HER) electrocatalysts for future clean and renewable energy system has excited significant research interests over the recent years. In this communication, the polymorphic tungsten diphosphide (p-WP2) nanoparticles with mixed monoclinic (α-) and orthorhombic (β-) phases are synthesized by phase-controlled phosphidation route via vacuum capsulation and explored as a novel efficient electrocatalyst towards HER. The p-WP2 catalyst delivers superior performance with excellent stability under both acidic and alkaline conditions over its single phases of α-WP2 and β-WP2. This finding demonstrates that a highly efficient hybrid electrocatalyst can be achieved via precise composition controlling and may open up exciting opportunities for their practical applications toward energy conversion.

  3. Comment on ``Monoclinic phase of PbZr0.52Ti0.48O3 ceramics: Raman and phenomenological thermodynamic studies''

    Science.gov (United States)

    Frantti, J.; Lappalainen, J.; Lantto, V.; Nishio, S.; Kakihana, M.

    2001-05-01

    Recently, Souza Filho et al. [A. G. Souza Filho, K. C. V. Lima, A. P. Ayala, I. Guedes, P. T. C. Freire, J. Mendes Filho, E. B. Araujo, and J. A. Eiras, Phys. Rev. B 61, 14 283 (2000)] reported a phase transition between monoclinic and tetragonal phases as a function of temperature in a PbZr0.52Ti0.48O3 ceramic sample, observed by Raman spectroscopy. We show that their observation has no relation to the phase transition and the anomaly they interpreted as an indication of a phase transition was due to the erroneous curve fit procedure, which predicts a clearly observable phase transition for all tetragonal lead-zirconate-titanate ceramics, including lead titanate. A more appropriate way to study this phase transition phenomena by Raman spectroscopy is discussed.

  4. Off-resonance effects in (14)N NQR signals from the pulsed spin-locking (PSL) and three-pulse echo sequence; a study for monoclinic TNT.

    Science.gov (United States)

    Smith, John A S; Rowe, Michael D; Althoefer, Kaspar; Peirson, Neil F; Barras, Jamie

    2015-10-01

    In NQR detection applications signal averaging by the summation of rapidly regenerated signals from multiple pulse sequences of the pulsed spin-locking (PSL) type is often used to improve sensitivity. It is important to characterise and if possible minimise PSL sequence off-resonance effects since they can make it difficult to optimise detection performance. We illustrate this with measurements of the variation of the decay time T2e and the amplitude of PSL signal trains with pulse spacing and excitation offset frequency for the 870 kHz ν+(14)N NQR line of monoclinic TNT under carefully stabilised temperature conditions. We have also carried out a similar study of signals from monoclinic TNT and 1H-1,2,3-triazole generated by a three-pulse echo sequence and the results are shown to agree well with a theoretical treatment appropriate to polycrystalline NQR samples such as TNT for which spin I=1, asymmetry parameter η≠0 and T1≫T2. Based on this theory we derive simple models for calculating TNT PSL signal trains and hence the pulse spacing and off-resonance dependence of signal amplitude and T2e which we compare to our experimental data. We discuss the influence of PSL echo summation on off-resonance effects in detected signal intensity and show how a phase-alternated multiple pulse sequence can be used in combination with the PSL sequence to eliminate variation in detection performance due to off-resonance effects.

  5. Magnetic characterization of non-ideal single-domain monoclinic pyrrhotite and its demagnetization under hydrostatic pressure up to 2 GPa with implications for impact demagnetization

    Science.gov (United States)

    Bezaeva, Natalia S.; Chareev, Dmitriy A.; Rochette, Pierre; Kars, Myriam; Gattacceca, Jérôme; Feinberg, Joshua M.; Sadykov, Ravil A.; Kuzina, Dilyara M.; Axenov, Sergey N.

    2016-08-01

    Here we present a comprehensive magnetic characterization of synthesized non-ideal single-domain (SD) monoclinic pyrrhotite (Fe7S8). The samples were in the form of a powder and a powder dispersed in epoxy. "Non-ideal" refers to a powder fraction of predominantly SD size with a minor contribution of small pseudo-single-domain grains; such non-ideal SD pyrrhotite was found to be a remanence carrier in several types of meteorites (carbonaceous chondrites, SNC…), which justifies the usage of synthetic compositions as analogous to natural samples. Data were collected from 5 to 633 K and include low-field magnetic susceptibility (χ0), thermomagnetic curves, major hysteresis loops, back-field remanence demagnetization curves, first-order reversal curves (FORCs), alternating field and pressure demagnetization of saturation isothermal remanent magnetization (SIRM), low temperature data (such as zero-field-cooled and field-cooled remanence datasets together with room temperature SIRM cooling-warming cycles) as well as XRD and Mössbauer spectra. The characteristic Besnus transition is observed at ∼33 K. FORC diagrams indicate interacting SD grains. The application of hydrostatic pressure up to 2 GPa using nonmagnetic high-pressure cells resulted in the demagnetization of the sample by 32-38%. Repeated cycling from 1.8 GPa to atmospheric pressure and back resulted in a total remanence decrease of 44% (after 3 cycles). Pressure demagnetization experiments have important implications for meteorite paleomagnetism and suggest that some published paleointensities of meteorites with non-ideal SD monoclinic pyrrhotite as remanence carrier may be lower limits because shock demagnetization was not accounted for.

  6. FINAL REPORT: DOE CONTRACT NUMBER FG0205ER64026 Biological Neutron Scattering: A Collaboration with the Oak Ridge Center for Structural Molecular Biology

    Energy Technology Data Exchange (ETDEWEB)

    Trewhella, Jill [Univ. of Utah, Salt Lake City, UT (United States)

    2011-01-12

    The overarching goal of this project was to promote applications of small-angle scattering in structural molecular biology by providing model examples of cutting edge applications that demonstrate the unique capabilities and potential of the DOE national user facilities at Oak Ridge, especially the newly commissioned BioSANS. The approach taken was three-fold: (1) to engage in high impact collaborative research projects that would benefit from small-angle neutron scattering to both demonstrate the power of the technique while expanding the potential user community; (2) to provide access to scattering facilities established at the University of Utah to as broad a set of researchers as possible to increase the expertise in small-angle scattering generally; and (3) to develop new methods and tools for small-angle scattering. To these ends, three major research collaborations were pursued that resulted in a significant body of published work where neutron scattering and contrast variation played a major role. These major collaborations involved studies of protein complexes involved in (1) bacterial transcription regulation and adaptive response (a DOE/BER priority area); (2) regulation of cardiac muscle; and (3) neuronal disorders. In addition, to broaden the impact of the project, smaller collaborative efforts were supported that used either small-angle X-ray or neutron scattering. Finally, the DOE supported facilities at the University of Utah were made available to researchers on a service basis and a number of independent groups took advantage of this opportunity. In all of this work, there was an emphasis on the training of students and post docs in scattering techniques, and a set of publications (a book chapter, a review, and an encyclopedia article) were produced to guide the non-specialist potential user of scattering techniques in successful applications of the techniques. We also developed a suite of user friendly web-based computational tools currently

  7. Monoclinic crystal form of Aspergillus niger alpha-amylase in complex with maltose at 1.8 A resolution

    NARCIS (Netherlands)

    Vujicic-Zagar, A.; Dijkstra, B. W.; Vujičić-Žagar, A.

    Aspergillus niger alpha-amylase catalyses the hydrolysis of alpha-1,4-glucosidic bonds in starch. It shows 100% sequence identity to the A. oryzae homologue (also called TAKA-amylase), three crystal structures of which have been published to date. Two of them belong to the orthorhombic space group

  8. Structural Transition of Gd2O3:Eu Induced by High Pressure

    Institute of Scientific and Technical Information of China (English)

    CHEN Hai-Yong; ZOU Guang-Tian; HE Chun-Yuan; GAO Chun-Xiao; ZHANG Jia-Hua; GAO Shi-Yong; LU Hong-Liang; NIE Yan-Guang; LI Dong-Mei; KAN Shi-Hai

    2007-01-01

    @@ The structural transition of bulk and nano-size Gd2O3:Eu are studied by high pressure energy disperse x-ray diffraction (XRD) and high pressure photoluminescence. Our results show that in spite of different size of Gd2O3 particles, the cubic structure turns into a possible hexagonal one above 13.4 GPa. When the pressure is released,the sample reverses to the monoclinic structure. No cubic structure presents in the released samples. That is to say, the compression and relaxation of the sample leads to the cubic Gd2O3:Eu then turns into the monoclinic one.

  9. X-ray structure, hydrogen bonding and lattice energy analysis of (2$E$)-1-(anthracen-9-yl)-3-(4-substitutedphenyl)prop-2-en-1-ones

    Indian Academy of Sciences (India)

    VINUTHA V SALIAN; B NARAYANA; K BYRAPPA; B K SAROJINI; RAJNI KANT

    2016-12-01

    (2$E$)-1-(anthracen-9-yl)-3-(4-chlorophenyl)prop-2-en-1-ones and (2$E$)-1-(anthracen-9-yl)-3-(4-nitrophenyl) prop-2-en-1-ones crystallize in the monoclinic crystal system with space group P2$_1$/c. Single-crystal X-ray diffraction data for both the compounds were collected on an X’Calibur CCD area detector diffractometer (Oxford Diffraction)using Mo$K\\alpha$ radiation ($\\lambda = 0.7107$ $\\AA$) at 293(2) K. The crystal structures were solved by direct methods and refined by full-matrix least-square procedures to a final $R$ value of 0.0468 [I] and 0.0486 [II]. The crystal structures as elucidated by X-ray diffraction methods show the presence of a few intermolecular interactions, and the nature and energetics associated with these interactions have been characterized using PIXEL software.

  10. Synthesis and Crystal Structure of a Cyano-bridged Bimetallic Complex K3(TMS)2(H2O)2Cr(CN)6 [TMS = Tetramethylene Sulfone

    Institute of Scientific and Technical Information of China (English)

    CHEN Wei; CHE Yun-Xia; ZHENG Ji-Min

    2005-01-01

    The cyano-bridged bimetallic complex K3(TMS)2(H2O)2Cr(CN)6 with three- dimensional microporous structure was synthesized and characterized. The title complex (C14H20CrK3N, Mr = 601.78) crystallizes in monoclinic, space group C2/c with a = 14.357(4), b = 9.331(3), c = 19.180(6)(A), β = 96.754(5)o, V = 2551.6(13) (A)3, Z = 4, Dc = 1.567 g/m3, μ(MoKα) = 1.141 mm-1, F(000) = 1228, the final R = 0.0440 and wR = 0.0990 for 1760 observed reflections (I > 2σ(I)). In the crystal, two [Cr(CN) 6]3- units, four K+ ions and two oxygen atoms of two TMS molecules are linked to form a sixteen-membered ring and an extended three-dimensional structure.

  11. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Philip L.

    2012-11-11

    Our research program was aimed at elucidating the nature of proton transport in ionomer membranes by means of a combination of analytical theory and molecular modeling. There were two broad thrusts. The first of these was directed towards understanding the equilibrium structure of Nafion and related polymers at various levels of hydration. The second thrust was concerned with the transport of protons through a membrane of this type. The research on structure proceeded by building on existing work, but with the introduction of some novel techniques, among which is a hybrid Molecular Dynamics--Monte Carlo approach. This method permits rapid computations by temporarily decoupling the motion of the polar side chains from that of the perfluorinated backbone, while still retaining the essential aspects of the constraint that phase separation can only continue to a very limited degree. Competition between an elastic energy due to this constraint and the tendency to phase separation lead to the equilibrium structure, which turns out to be qualitatively different at different levels of hydration. The use of a carefully formulated dielectric function was necessary to achieve accurate results. The work on transport of protons in Nafion-like membranes also involved a combination of theory and simulation. Atomistic molecular-dynamics simulations were employed to determine some of the characteristic parameters for the diffusion of hydronium in hydrated membranes. These results were used in a theoretical model of non-linear diffusion to predict transport coefficients. Among our results was the discovery that treatment with strong electric fields may enhance the properties of the polymer membranes. Our computer simulations showed that the vigorous application of a stretching force or an electric field can modify the structure of the ionomer that lies at the heart of a polymer-electrolyte-membrane fuel cell. If these predictions are verified experimentally, then it should be

  12. Cassini's Grand Finale: The Final Orbits

    Science.gov (United States)

    Spilker, Linda; Edgington, Scott

    2016-04-01

    The Cassini-Huygens mission, a joint collaboration between NASA, ESA and the Italian Space Agency, is approaching its last year of operations after nearly 12 years in orbit around Saturn. Cassini will send back its final bits of unique data on September 15th, 2017 as it plunges into Saturn's atmosphere, vaporizing and satisfying planetary protection requirements. Before that time Cassini will continue its legacy of exploration and discovery with 12 close flybys of Titan in 2016 and 2017 that will return new science data as well as sculpt the inclinations and periods of the final orbits. Even though all of our close icy satellite flybys, including those of Enceladus, are now completed, numerous Voyager-class flybys (summer solstice approaches. In November 2016 Cassini will transition to a series of orbits with peripases just outside Saturn's F ring. These 20 orbits will include close flybys of some tiny ring moons and excellent views of the F ring and outer A ring. The 126th and final close flyby of Titan will propel Cassini across Saturn's main rings and into its final orbits. Cassini's Grand Finale, starting in April 2017, is comprised of 22 orbits at an inclination of 63 degrees. Cassini will repeatedly dive between the innermost rings and the upper atmosphere of the planet providing insights into fundamental questions unattainable during the rest of the mission. Cassini will be the first spacecraft to explore this region. These close orbits provide the highest resolution observations of both the rings and Saturn, and direct in situ sampling of the ring particles, composition, plasma, Saturn's exosphere and the innermost radiation belts. Saturn's gravitational field will be measured to unprecedented accuracy, providing information on the interior structure of the planet, winds in the outer layers of Saturn's atmosphere, and the mass distribution in the rings. Probing the magnetic field will give insight into the nature of the magnetic dynamo, telling us: why the

  13. Schedulability Analysis for Java Finalizers

    DEFF Research Database (Denmark)

    Bøgholm, Thomas; Hansen, Rene Rydhof; Søndergaard, Hans

    2010-01-01

    Java finalizers perform clean-up and finalisation of objects at garbage collection time. In real-time Java profiles the use of finalizers is either discouraged (RTSJ, Ravenscar Java) or even disallowed (JSR-302), mainly because of the unpredictability of finalizers and in particular their impact...... on the schedulability analysis. In this paper we show that a controlled scoped memory model results in a structured and predictable execution of finalizers, more reminiscent of C++ destructors than Java finalizers. Furthermore, we incorporate finalizers into a (conservative) schedulability analysis for Predictable Java...... programs. Finally, we extend the SARTS tool for automated schedulability analysis of Java bytecode programs to handle finalizers in a fully automated way....

  14. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Joseph H. Simmons; Tracie J. Bukowski

    2002-08-07

    This grant was a continuation of research conducted at the University of Florida under Grant No. DE-FG05-91ER45462 in which we investigated the energy bandgap shifts produced in semiconductor quantum dots of sizes between 1.5 and 40 nm. The investigated semiconductors consisted of a series of Column 2-6 compounds (CdS, CdSe, CdTe) and pure Column IV elements (Si and Ge). It is well-known of course that the 2-6 semiconductors possess a direct-gap electronic structure, while the Column IV elements possess an indirect-gap structure. The investigation showed a major difference in quantum confinement behavior between the two sets of semiconductors. This difference is essentially associated with the change in bandgap energy resulting from size confinement. In the direct-gap semiconductors, the change in energy (blue shift) saturates when the crystals approach 2-3 nm in diameter. This limits the observed shift in energy to less than 1 eV above the bulk value. In the indirect-gap semiconductors, the energy shift does not show any sign of saturation and in fact, we produced Si and Ge nanocrystals with absorption edges in the UV. The reason for this difference has not been determined and will require additional experimental and theoretical studies. In our work, we suggest, but do not prove that mixing of conduction band side valleys with the central valley under conditions of size confinement may be responsible for the saturation in the blue-shift of direct-gap semiconductors. The discovery of large bandgap energy shifts with crystal size prompted us to suggest that these materials may be used to form photovoltaic cells with multi-gap layers for high efficiency in a U.S. Patent issued in 1998. However, this possibility depends strongly on the ability to collect photoexcited carriers from energy-confined crystals. The research conducted at the University of Arizona under the subject grant had a major goal of testing an indirect gap semiconductor in size-confined structures to

  15. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Webb, Robert C. [Texas A& M University; Kamon, Teruki [Texas A& M University; Toback, David [Texas A& M University; Safonov, Alexei [Texas A& M University; Dutta, Bhaskar [Texas A& M University; Dimitri, Nanopoulos [Texas A& M University; Pope, Christopher [Texas A& M University; White, James [Texas A& M University

    2013-11-18

    Overview The High Energy Physics Group at Texas A&M University is submitting this final report for our grant number DE-FG02-95ER40917. This grant has supported our wide range of research activities for over a decade. The reports contained here summarize the latest work done by our research team. Task A (Collider Physics Program): CMS & CDF Profs. T. Kamon, A. Safonov, and D. Toback co-lead the Texas A&M (TAMU) collider program focusing on CDF and CMS experiments. Task D: Particle Physics Theory Our particle physics theory task is the combined effort of Profs. B. Dutta, D. Nanopoulos, and C. Pope. Task E (Underground Physics): LUX & NEXT Profs. R. Webb and J. White(deceased) lead the Xenon-based underground research program consisting of two main thrusts: the first, participation in the LUX two-phase xenon dark matter search experiment and the second, detector R&D primarily aimed at developing future detectors for underground physics (e.g. NEXT and LZ).

  16. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Kouvetakis, John

    2013-01-03

    The project addressed the need for improved multijunction solar cells as identified within the Solar America Initiative program. The basic Ge/InGaAs/InGaP triple-junction structure that has led to record commercial efficiencies remains unoptimized due to excess current in the germanium component. Furthermore, its deployment cannot be scaled up to terawatt-level applications due to bottlenecks related to germanium's cost and abundance. The purpose of the program was to explore new strategies developed at Arizona State University to deposit germanium films on much cheaper silicon substrates, largely eliminating the germanium bottleneck, and at the same time to develop new materials that should lead to an improvement in multijunction efficiencies. This included the ternary alloy SiGeSn, which can be inserted as a fourth junction in a Ge/SiGeSn/InGaAs/InGaP structure to compensate for the excess current in the bottom cell. Moreover, the possibility of depositing materials containing Sn on Si substrates created an opportunity for replacing the bottom Ge cell with a GeSn alloy, which, combined with new III-V alloys for the top cells, should enable 4-junction structures with perfectly optimized band gaps. The successes of the program, to be described below, has led to the developments of new strategies for the growth of high-quality germanium films on Si substrates and to a widespread recognition that SiGeSn is likely to play a significant role in future generations of high-efficiency devices, as demonstrated by new research and intellectual property efforts by major US industrial players.

  17. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, Pulak

    2013-04-01

    The overall goal of this project was the exploration of new ways to make organic and hybrid (organic-inorganic) materials for energy-related applications. Towards this end, our research focused on the structure and behavior of molecular monolayers at interfaces (including floating monolayers, transferred Langmuir-Blodgett monolayers, and self-assembled monolayers), as well as the biomimetic nucleation of inorganic crystals at soft-hard interfaces. The project resulted in a number of 'firsts' and other notable achievements, which are described in the report.

  18. Pressure-induced structure phase transition on Y sub 2 O sub 3

    CERN Document Server

    Ma Yan Ming; Ma Hong An; Pan Yue Wu; Cui Qi Liang; Liu Bing Bing; Cui Tian; Zou Guang Tian; LiuJing

    2002-01-01

    Diamond anvil cell (DAC) is adopted to carry out in situ high pressure measurements for Y sub 2 O sub 3 powder sample in the range from ambient to 23 GPa, by using synchrotron X-ray diffraction method. Two structural phase transitions were observed in the pressure range. At P = 12.8 GPa, Y sub 2 O sub 3 transforms from cubic to monoclinic structure. At P = 21.8 GPa, Y sub 2 O sub 3 transforms from monoclinic to another new phase. However, the crystal structure of the new phase cannot be determined, because the diffraction pattern of the sample disappears. The decompressed sample is monoclinic structure, indicating that the first pressure-induced phase transition is irreversible

  19. Impact of the oxygen defects and the hydrogen concentration on the surface of tetragonal and monoclinic ZrO2 on the reduction rates of stearic acid on Ni/ZrO2

    Energy Technology Data Exchange (ETDEWEB)

    Foraita, Sebastian D.; Fulton, John L.; Chase, Zizwe A.; Vjunov, Aleksei; Xu, Pinghong; Barath, Eszter; Camaioni, Donald M.; Zhao, Chen; Lercher, Johannes A.

    2015-02-02

    The effect of the physicochemical properties of ZrO2 phases on the activity of Ni/ZrO2 catalysts for hydrodeoxygenation of stearic acid are described. A synergistic interaction between Ni and ZrO2 support was found. The effect is greatest for the monoclinic phase of ZrO2.

  20. Synthesis and Crystal Structure of [{Cd(hmbdc)(H2O)3}·2H2O]n

    Institute of Scientific and Technical Information of China (English)

    HU Yue-Hua; WANG Yan; WANG Zuo-Wei; LI Yi-Zhi; ZHENG He-Gen

    2007-01-01

    A novel coordination polymer [{Cd(hmbdc)(H2O)3}·2H2O]n (hmbdc=5-hydroxy- isophthalic acid) has been synthesized and characterized by elemental analysis, IR spectra and single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/c, with a=9.599(3), b=18.699(5), c=7.557(2) (A), β= 108.198(4)°, V=1288.6(6) (A)3, Z=4, Mr=382.60, Dc=1.972 g/cm3, F(000)=760, μ=1.740, the final R=0.0555 and wR=0.0995 for 1732 observed reflections with Ⅰ > 2σ(Ⅰ). The structural analysis shows that the intermolecular hydrogen bonds and π-π interactions result in a three-dimensional supramolecular framework.

  1. Synthesis and Crystal Structure of a N,N,N'-tri(2-hydroxy-5-methylbenzyl)-l,2-ethanediamine

    Institute of Scientific and Technical Information of China (English)

    WANG Nuan-Sheng; WANG Yong-Tao; LI Jun-Ying; LI Tian-Duo

    2011-01-01

    An aminophenol ligand, N,N,N'-tri(2-hydroxy-5-methylbenzyl)-l,2-ethanediamine, was prepared through the Marmich reaction, and structurally characterized by NMR, IR, MS and single-crystal X-ray diffraction. The title compound (C26H32N2O3, Mr = 420.54) belongs to the monoclinic system, space group P21/n with a = 8.6233(14), b = 10.2655(16), c = 26.017(4) A, β = 95.797(2)°, V = 2291.3(6) A^3, Z = 4, the final R = 0.0461 and wR = 0.1139 for 4267 unique reflections (Rint = 0.028) with 11691 observed ones (I〉 2a(I)).

  2. Synthesis and Crystal Structure of 3,3'-(4-Dimethylaminobenzylidene)- bis-(4-hydroxycoumarin)

    Institute of Scientific and Technical Information of China (English)

    LV Chang-Wei; WU Yao-Ping; LIU Jian; JIA Xin-Gang

    2012-01-01

    The title compound 3,3'-(4-dimethylaminobenzylidene)-bis-(4-hydroxycoumarin) 3 was synthesized by the reaction of 4-hydroxycoumarin with 4-dimethylaminobenzaldehyde, and its chemical structure was determined by X-ray single-crystal diffraction. It crystallizes in monoclinic, space group P21/n with a = 11.698(2), b = 10.882(2), c = 16.594(3) A, β = 90.69(3)°, V = 2112.1(7) A3, Z = 4, F(000) = 952, Dc = 1.432 Mg/m3, Mr = 455.45,μ= 0.102 mm-1, 2 = 0.71073 A, the final R = 0.0779 and wR = 0.2143 for 3031 observed reflections with I 〉 2σ(I).

  3. Synthesis and Crystal Structure of A New Armed-tetraazacrown Ether and Its Liquid Membrane Transport of Alkali Metal Cations

    Institute of Scientific and Technical Information of China (English)

    马淑兰; 朱文祥; 董淑静; 郭倩玲; 佘远斌

    2003-01-01

    A new tetra-N-substituted tetraazacrown ether derivative, 4,7,13,16-tetra ( 2-cyanobenzyl)-1, 10-dioxa-4, 7, 13, 16-tetraazacy-dooctademne, C44H48N8O2, has been synthesized and struc-turally characterized. It crystallizes in the monoclinic system,Slmeegroup P21/c with a = 1.1176(3) nm, b =2.1906(7) nm,c=0.8430(3)nm, V=2.0132(10)nm3, β = 102.740(5)°,Z=4, Dc= 1.189 g/cm3, final R1=0.0460, wR2=0.0803.The liquid membrane transports of alkali metal cations using the new macrocyde as the ion-carrier were also studied. Com-pared with some macrocyclic ligands, our newly synthesized lig.and showed a good selectivity ratio for Na Na+/Li+.

  4. Synthesis and Crystal Structure of K3[HO{VO(O2)2}2]·H2O

    Institute of Scientific and Technical Information of China (English)

    张红艳; 黄尊行; 郭鸿旭

    2004-01-01

    The title compound K3[HO{VO(O2)2}2]·H2O has been synthesized and its crystal structure was determined by X-ray diffraction method. The crystal is of monoclinic, space group P21/c with a = 6.7078(3), b = 9.9539(6), c = 15.8182(9)A, β = 93.702(3)0, V = 1053.96(10)A3, Mr = 414.20, Dc = 2.610 g/cm3, Z = 4, λ(MoKα) = 0.71073A, F(000) = 808, μ = 3.014 mm-1, the final R = 0.0173 and wR = 0.0466 for 2178 observed reflections with I > 2σ(I). X-ray diffraction reveals that the coordination polyhedra of V atoms are not chemically equivalent: the V(1) and V(2) polyhedra can be described as pentagonal pyramid and pentagonal bipyramid, respectively.

  5. ''Stabilization of monoclinic SrAl{sub 2}O{sub 4} through the formation of solid solutions of the type SrAl{sub 2-x}B{sub x}O{sub 4}''

    Energy Technology Data Exchange (ETDEWEB)

    Marchal, M.; Cordoncillo, E.; Escribano, P.; Carda, J.B. [Universitat Jaume I, Castellon (Spain). Dept. de Quimica Inorganica; Vallet-Regi, M. [Dept. de Quimica Inorganica y Bioinorganica, Univ. Complutense (UCM), Madrid (Spain)

    2002-07-01

    The aim of this work is to study the synthesis conditions for preparing SrAl{sub 2}O{sub 4} at low temperature and its stabilization as a monoclinic form by synthesis of solid solutions of the type SrAl{sub 2-x}B{sub x}O{sub 4} (x = 0, 0.1, 0.2, 0.3). The addition of boron can reduce the synthesis temperature of SrAl{sub 2}O{sub 4} because it can provide a liquid medium and increase the diffusion rate and also it can replace the Al (III) ions in the tetrahedral sites of the structure and the distortions caused because of its low ionic radius compared to the aluminium one, could explain the observed reduction in synthesis temperature. (orig.)

  6. Luminescence and cathodoluminescent properties of monoclinic Y2WO6 co-doped with Dy-Bi

    Science.gov (United States)

    Hu, Peiju; Zhang, Wei; Hu, Zhengfa; Feng, Zuyong; Ma, Lun; Zhang, Xiuping; Sheng, Xia; Luo, Li; Wang, Yinhai

    2017-08-01

    Dy-Bi co-doped yttrium tungstate crystal materials were synthesized by high temperature solid-state method. To reveal the photoluminescence features and properties of the samples, some measurements have been taken. It turned out that different Bi3+ concentrations play obvious influence in emission performance, and show visible light emission under ultraviolet light excitation. Besides, the effect of temperature on phase structure of samples has also been studied here. Superhigh X-ray luminescence of the phosphors exhibited the promising application in the field of high energy detection. The X-ray irradiation crystal resistance stability of the phosphors has also been investigated through the subsequent testing of XRD and spectra.

  7. FINAL REPORT

    Energy Technology Data Exchange (ETDEWEB)

    Juergen Eckert; Anthony K. Cheetham (Principal Investigator)

    2011-03-11

    Hydrogen storage systems based on the readily reversible adsorption of H{sub 2} in porous materials have a number of very attractive properties with the potential to provide superior performance among candidate materials currently being investigated were it not for the fact that the interaction of H{sub 2} with the host material is too weak to permit viable operation at room temperature. Our study has delineated in quantitative detail the structural elements which we believe to be the essential ingredients for the future synthesis of porous materials, where guest-host interactions are intermediate between those found in the carbons and the metal hydrides, i.e. between physisorption and chemisorption, which will result in H{sub 2} binding energies required for room temperature operation. The ability to produce porous materials with much improved hydrogen binding energies depends critically on detailed molecular level analysis of hydrogen binding in such materials. However, characterization of H{sub 2} sorption is almost exclusively carried by thermodynamic measurements, which give average properties for all the sites occupied by H{sub 2} molecules at a particular loading. We have therefore extensively utilized the most powerful of the few molecular level experimental probes available to probe the interactions of hydrogen with porous materials, namely inelastic neutron scattering (INS) spectroscopy of the hindered rotations of the hydrogen molecules adsorbed at various sites, which in turn can be interpreted in a very direct way in by computational studies. This technique can relate spectral signatures of various H{sub 2} molecules adsorbed at binding sites with different degrees of interaction. In the course of this project we have synthesized a rather large number of entirely new hybrid materials, which include structural modifications for improved interactions with adsorbed hydrogen. The results of our systematic studies on many porous materials provide detailed

  8. Cassini's Grand Finale

    Science.gov (United States)

    Spilker, L. J.; Edgington, S. G.; Altobelli, N.

    2016-12-01

    After more than 12 years in Saturn orbit, the Cassini-Huygens mission has entered its final year of data collection. Cassini will return its final bits of unique data on 15 September 2017 as it plunges into Saturn's atmosphere, vaporizing and satisfying planetary protection requirements. Since early 2016 Cassini's orbital inclination was slowly increased towards its final inclination. In November Cassini transitioned to a series of 20 orbits with peripases just outside Saturn's F ring that include some of the closest flybys of the tiny ring moons and excellent views of the F ring and outer A ring. Cassini's final close flyby of Titan will propel it across Saturn's main rings and into its final orbits. Cassini's Grand Finale begins in April 2017 and is comprised of 22 orbits at an inclination of 63 degrees. Cassini will repeatedly dive between the innermost ring and Saturn's upper atmosphere providing insights into fundamental questions unattainable during the rest of the mission. It will be the first spacecraft to explore this region. These close orbits provide the highest resolution observations of both the rings and Saturn, and direct in situ sampling of the ring particles' composition, plasma, Saturn's exosphere and the innermost radiation belts. Saturn's gravitational field will be measured to unprecedented accuracy, providing information on Saturn's interior structure and mass distribution in the rings. Probing the magnetic field will give insight into the nature of the magnetic dynamo and the true rotation rate of Saturn's interior. The ion and neutral mass spectrometer will sniff the exosphere and upper atmosphere and examine water-based molecules originating from the rings. The cosmic dust analyzer will sample particle composition from different parts of the main rings. Recent science highlights and science objectives from Cassini's final orbits will be discussed. This work was carried out in part at the Jet Propulsion Laboratory, California Institute of

  9. Solvent effect in monoclinic to hexagonal phase transformation in LaPO{sub 4}:RE (RE=Dy{sup 3+}, Sm{sup 3+}) nanoparticles: Photoluminescence study

    Energy Technology Data Exchange (ETDEWEB)

    Phaomei, Ganngam [Department of Chemistry, Manipur University, Manipur 795003 (India); Rameshwor Singh, W., E-mail: dr.rmsingh@yahoo.co.i [Department of Chemistry, Manipur University, Manipur 795003 (India); Ningthoujam, R.S., E-mail: rsn@barc.gov.i [Chemistry Division, Bhabha Atomic Research Center, Mumbai 400085 (India)

    2011-06-15

    Nanosized phosphor materials, LaPO{sub 4}:RE (RE=Dy{sup 3+}, Sm{sup 3+}) have been synthesized using water, dimethyl sulfoxide (DMSO), ethylene glycol (EG) and mixed solvents at a relatively low temperature of 150 {sup o}C. X-ray diffraction (XRD) study reveals that as-prepared nanoparticles prepared in DMSO and EG are well crystalline and correspond to monoclinic phase. In the mixed water-DMSO or water-EG solvents, XRD patterns are in good agreement with hexagonal phase, but transformed to monoclinic phase at higher temperature of 900 {sup o}C. TEM images show well-dispersed and rice-shaped nanoparticles of diameter 5-10 nm, length of 13-37 nm for Dy{sup 3+}-doped LaPO{sub 4} and diameter of 25-35 nm, length of 73-82 nm for Sm{sup 3+}-doped LaPO{sub 4}. Dy{sup 3+}-doped LaPO{sub 4} shows two prominent emission peaks at 480 and 572 nm corresponding to {sup 4}F{sub 9/2}{yields}{sup 6}H{sub 15/2} (magnetic dipole) and {sup 4}F{sub 9/2}{yields}{sup 6}H{sub 13/2} (electric dipole) transitions, respectively. Similarly, for Sm{sup 3+}-doped LaPO{sub 4}, three prominent emission peaks at 561, 597 and 641 nm were observed corresponding to {sup 4}G{sub 5/2}{yields}{sup 6}H{sub 5/2}, {sup 4}G{sub 5/2}{yields}{sup 6}H{sub 7/2} (magnetic dipole) and {sup 4}G{sub 5/2}{yields}{sup 6}H{sub 9/2} (electric dipole) transitions, respectively. The luminescence intensity of the sample prepared in EG is more than that of DMSO or mixed solvents. Enhancement of luminescence is also observed after heat-treatment at 900 {sup o}C due to removal of quencher such as water, organic moiety and surface defects/dangling bonds. The samples are re-dispersible in polar solvent and can be incorporated in polymer film. - Research highlights: Nanomaterials. Optical properties. Luminescence materials.

  10. Syntheses and Crystal Structures of Two VO(IV) Schiff Base Complexes with Oxyammonia Ligand

    Institute of Scientific and Technical Information of China (English)

    李连之; 许涛; 王大奇; 牛梅菊; 冀海伟

    2004-01-01

    Two novel VO(IV) Schiff base complexes, VO(SALHA)2[SALHA: salicyaldehydeoxyammonia] and VO(o-VANHA)2 [o-VANHA: o-vanillin-oxyammonia], have been synthesized with salicyaldehyde or o-vanilline, hydroxylammonium chloride and vanadyl sulfate in absolute methanol, and their crystal structures were determined by single-crystal X-ray diffraction. The vanadium(IV) centers in both complexes are five-coordinate in a distorted square pyramidal geometry. VO(SALHA)2 (C14H12N2O5V, Mr = 339.20) crystallizes in the monoclinic system, space group P21/n with a = 14.716(9), b = 7.175(5), c = 14.716(9) A, β = 113.130(7), V = 1428.8(15) A3, Z = 4, Dc = 1.577 g/cm3, β = 0.71073 A, μ(MoKα) = 0.720 mm-1, F(000) = 692, the final R = 0.0466 and wR = 0.0829 for 1561 observed reflections (I > 2σ(I)). VO(o-VANHA)2 (C16H16N2O7V, Mr = 399.25) is of monoclinic, space group P21/n with a = 11.386(12), b = 10.405(10), c = 14.627(15) A, β = 93.654(19), V = 1729(3) A3, Z = 4, Dc = 1.533 g/cm3, β = 0.71073 A, μ(MoKα) = 0.615 mm-1, F(000) = 820, the final R = 0.0513 and wR = 0.1129 for 1235 observed reflections (I > 2σ(I)).

  11. A Process for Modelling Diffuse Scattering from Disordered Molecular Crystals, Illustrated by Application to Monoclinic 9-Chloro-10-methylanthracene

    Directory of Open Access Journals (Sweden)

    D. J. Goossens

    2015-01-01

    Full Text Available Diffuse scattering from a crystal contains valuable information about the two-body correlations (related to the nanoscale order in the material. Despite years of development, the detailed analysis of single crystal diffuse scattering (SCDS has yet to become part of the everyday toolbox of the structural scientist. Recent decades have seen the pair distribution function approach to diffuse scattering (in fact, total scattering from powders become a relatively routine tool. However, analysing the detailed, complex, and often highly anisotropic three-dimensional distribution of SCDS remains valuable yet rare because there is no routine method for undertaking the analysis. At present, analysis requires significant investment of time to develop specialist expertise, which means that the analysis of diffuse scattering, which has much to offer, is not incorporated thorough studies of many compounds even though it has the potential to be a very useful adjunct to existing techniques. This article endeavours to outline in some detail how the diffuse scattering from a molecular crystal can be modelled relatively quickly and largely using existing software tools. It is hoped this will provide a template for other studies. To enable this, the entire simulation is included as deposited material.

  12. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Hameed A. Naseem, Husam H. Abu-Safe

    2007-02-09

    The purpose of this project was to investigate metal-induced crystallization of amorphous silicon at low temperatures using excitation sources such as laser and rapid thermal annealing, as well as, electric field. Deposition of high quality crystalline silicon at low temperatures allows the use of low cost soda-lime glass and polymeric films for economically viable photovoltaic solar cells and low cost large area flat panel displays. In light of current and expected demands on Si supply due to expanding use of consumer electronic products throughout the world and the incessant demand for electric power the need for developing high grade Si thin films on low cost substrate becomes even more important. We used hydrogenated and un-hydrogenated amorphous silicon deposited by plasma enhanced chemical vapor deposition and sputtering techniques (both of which are extensively used in electronic and solar cell industries) to fabricate nano-crystalline, poly-crystalline (small as well as large grain), and single-crystalline (epitaxial) films at low temperatures. We demonstrated Si nanowires on flat surfaces that can be used for fabricating nanometer scale transistors. We also demonstrated lateral crystallization using Al with and without an applied electric field. These results are critical for high mobility thin film transistors (TFT) for large area display applications. Large grain silicon (~30-50 µm grain size for < 0.5 µm thick films) was demonstrated on glass substrates at low temperatures. We also demonstrated epitaxial growth of silicon on (100) Si substrates at temperatures as low as 450°C. Thin film Si solar cells are being projected as the material of choice for low cost high efficiency solar cells when properly coupled with excellent light-trapping schemes. Ar ion laser (CW) was shown to produce dendritic nanowire structures at low power whereas at higher powers yielded continuous polycrystalline films. The power density required for films in contact with Al

  13. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhuomin

    2017-08-28

    Aligned doped-silicon nanowire (D-SiNW) arrays form a hyperbolic metamaterial in the mid-infrared and have unique thermal radiative properties, such as broadband omnidirectional absorption, low-loss negative refraction, etc. A combined theoretical and experimental investigation will be performed to characterize D-SiNW arrays and other metamaterials for tailoring thermal radiative properties. Near-field thermal radiation between anisotropic materials with hyperbolic dispersions will also be predicted for potential application in energy harvesting. A new kind of anisotropic metamaterial with a hyperbolic dispersion in a broad infrared region has been proposed and demonstrated based on aligned doped-silicon nanowire (D-SiNW) arrays. D-SiNW-based metamaterials have unique thermal radiative properties, such as broadband omnidirectional absorption whose width and location can be tuned by varying the filling ratio and/or doping level. Furthermore, high figure of merit (FOM) can be achieved in a wide spectral region, suggesting that D-SiNW arrays may be used as a negative refraction material with much less loss than other structured materials, such as layered semiconductor materials. We have also shown that D-SiNWs and other nanostructures can significantly enhance near-field thermal radiation. The study of near-field radiative heat transfer between closely spaced objects and the electromagnetic wave interactions with micro/nanostructured materials has become an emerging multidisciplinary field due to its importance in advanced energy systems, manufacturing, local thermal management, and high spatial resolution thermal sensing and mapping. We have performed extensive study on the energy streamlines involving anisotropic metamaterials and the applicability of the effective medium theory for near-field thermal radiation. Graphene as a 2D material has attracted great attention in nanoelectronics, plasmonics, and energy harvesting. We have shown that graphene can be used to

  14. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    J. K. Blasie; W.F. DeGrado; J.G. Saven; M.J. Therien

    2012-05-24

    The overall objective is to create robust artificial protein modules as scaffolds to control both (a) the conformation of novel cofactors incorporated into the modules thereby making the modules possess a desired functionality and (b) the organization of these functional modules into ordered macroscopic ensembles, whose macroscopic materials properties derive from the designed microscopic function of the modules. We focus on two specific types of cofactors for imparting functionality in this project; primarily nonlinear optical (NLO) chromophores designed to exhibit extraordinary molecular hyperpolarizabilities, as well as donor-bridge-acceptor cofactors designed to exhibit highly efficient, 'through-bonds' light-induced electron transfer (LIET) over nano-scale distances. The ensembles range from 2-D to 3-D, designed to possess the degree of orientational and positional order necessary to optimize their macroscopic response, the latter ranging from liquid-crystalline or glass-like to long-range periodic. Computational techniques, firmly based in statistical thermodynamics, are utilized for the design the artificial protein modules, based on robust {alpha}-helical bundle motifs, necessarily incorporating the desired conformation, location, and environment of the cofactor. Importantly, this design approach also includes optimization of the interactions between the modules to promote their organization into ordered macroscopic ensembles in 2-D and 3-D via either directed-assembly or self-assembly. When long-range periodic order is required, the design can be optimized to result a specified lattice symmetry. The structure and functionality of the individual modules are fully characterized at the microscopic level, as well as that of the ensembles at the macroscopic level, employing modern experimental physical-chemical and computational techniques. These include, for example, multi-dimensional NMR, various pump-probe transient spectroscopies to ultrafast time

  15. FINAL REPORT

    Energy Technology Data Exchange (ETDEWEB)

    PETER, GARY F. [UNIVERSITY OF FLORIDA

    2014-07-16

    Excellent progress was made in standardizing three complementary methods: Magnetic resonance imaging, x-ray micro CT, and MALDI imaging linear ion trap mass spectroscopy to image biomass and chemical, anatomical and functional changes that occur during pretreatment and hydrolysis. Magnetic resonance microscopy provides excellent images with as low as 5 uM resolution with hydrated biomass samples. We visualized dramatic changes in signal associated with the hydrolysis of the carbohydrates by strong acids. Quantitative diffusion approaches were used to probe more subtle structural changes in biomass. Diffusion tensor calculations reflect diffusion anisotropy and fractional anisotropy maps clearly show the longer range diffusion within the vessels compared to within the fiber cells. The diffusion is increased along the cell walls of the vessels. Suggesting that further research with NMR imaging should be pursued. X-ray CT provides excellent images at as low as 3.5 uM resolution from dried biomass. Small increases in surface area, and decreases in local density have been quantified in with wood after mild pretreatments; these changes are expected to be underestimates of the hydrated wood, due to the ~12% shrinkage that occurs upon drying untreated wood. MALDI-MS spectra show high ion intensities at most mass to charge ratios in untreated and pretreated woody material. MALDI-MSn is required to improve specificity and reduce background for imaging. MALDI-TOF is not specific enough for carbohydrate identification. Using MALDI-LIT/MSn we can readily identify oligomeric glucans and xylans and their fragmentation patterns as well as those of the glucuronic acid side chains of birch 4-O-methyl glucuronxylan. Imaging of glucan and xylan oligomers show that many contain isobaric ions with different distributions, indicating again that MSn is needed for accurate imaging of lignocellulosic materials. We are now starting to integrate the three imaging methods by using the same set

  16. Ag nanoparticle effects on the thermoluminescent properties of monoclinic ZrO{sub 2} exposed to ultraviolet and gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Villa-Sanchez, G [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca s/n La Marquesa, Ocoyoacac, Estado de Mexico, CP 52750 (Mexico); Mendoza-Anaya, D [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca s/n La Marquesa, Ocoyoacac, Estado de Mexico, CP 52750 (Mexico); Gutierrez-Wing, C [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca s/n La Marquesa, Ocoyoacac, Estado de Mexico, CP 52750 (Mexico); Perez-Hernandez, R [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca s/n La Marquesa, Ocoyoacac, Estado de Mexico, CP 52750 (Mexico); Gonzalez-MartInez, P R [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca s/n La Marquesa, Ocoyoacac, Estado de Mexico, CP 52750 (Mexico); Angeles-Chavez, C [Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, DF 07730 (Mexico)

    2007-07-04

    The goal of this work was to analyse ZrO{sub 2} in the pure state and when doped with Ag nanoparticles, by electron microscopy, x-ray diffraction and thermoluminescence methods. According to the results obtained, Ag nanoparticles did not modify the morphology or the crystalline structure of the ZrO{sub 2}. The thermoluminescent (TL) response of pure ZrO{sub 2} showed two peaks, one at 334 K and the other at 417 K, when it was exposed to ultraviolet (UV) radiation, and at 342 and 397 K when gamma radiation was used. For ZrO{sub 2} impregnated with Ag nanoparticles a diminished TL intensity due to nanoparticle shielding was observed, but the glow curve shape was similar. However, when Ag nanoparticles were added during the ZrO{sub 2} synthesis, a shift of the TL peaks towards higher temperature values with reference to pure ZrO{sub 2} was observed. A linear dependence of the integrated TL signal as a function of the irradiation dose was observed in all analysed samples. It was possible to determine some kinetic parameters, such as activation energy, kinetic order and frequency factor, using the sequential quadratic programming glow curve deconvolution; it was found that these values are highly dependent on the type of radiation used. Ag nanoparticles present in ZrO{sub 2} also modified the kinetic parameters, mainly when they were added during the synthesis of ZrO{sub 2}. Our results reinforce the possibilities of using pure and doped ZrO{sub 2} as an appropriate dosimetric material in radiation physics.

  17. Crystal structure and Hirshfeld surface analysis of 1-carboxy-2-(3,4-dihydroxyphenyl)ethan-1-aminium chloride 2-ammonio-3-(3,4-dihydroxyphenyl)propanoate: a new polymorph of l-dopa HCl and isotypic with its bromide counterpart

    OpenAIRE

    Perumal Kathiravan; Thangavelu Balakrishnan; Perumal Venkatesan; Kandasamy Ramamurthi; María Judith Percino; Subbiah Thamotharan

    2016-01-01

    The title molecular salt, C9H12NO4+·Cl−·C9H11NO4, is isotypic with that of the bromide counterpart [Kathiravan et al. (2016). Acta Cryst. E72, 1544–1548]. The title salt is a second monoclinic polymorph of the l-dopa HCl structure reported earlier in the monoclinic space group P21 [Jandacek & Earle (1971). Acta Cryst. B27, 841–845; Mostad & Rømming (1974). Acta Chemica Scand. B28, 1161–1168]. In the title compound, monoclinic space group I2, one of the dopa molecules has a positive charge wit...

  18. Crystal structure and Hirshfeld surface analysis of 1-carb­oxy-2-(3,4-di­hydroxy­phen­yl)ethan-1-aminium chloride 2-ammonio-3-(3,4-di­hydroxy­phen­yl)propano­ate: a new polymorph of l-dopa HCl and isotypic with its bromide counterpart

    OpenAIRE

    Kathiravan, Perumal; Balakrishnan, Thangavelu; Venkatesan, Perumal; Ramamurthi, Kandasamy; Percino, María Judith; Thamotharan, Subbiah

    2016-01-01

    The title mol­ecular salt, C9H12NO4 +·Cl−·C9H11NO4, is isotypic with that of the bromide counterpart [Kathiravan et al. (2016 ▸). Acta Cryst. E72, 1544–1548]. The title salt is a second monoclinic polymorph of the l-dopa HCl structure reported earlier in the monoclinic space group P21 [Jandacek & Earle (1971 ▸). Acta Cryst. B27, 841–845; Mostad & Rømming (1974 ▸). Acta Chemica Scand. B28, 1161–1168]. In the title compound, monoclinic space group I2, one of the dopa mol­ecules has a positive c...

  19. Equation of state and thermodynamic Grüneisen parameter of monoclinic 1,1-diamino-2,2-dinitroethylene

    Science.gov (United States)

    Zhang, Jianzhong; Velisavljevic, Nenad; Zhu, Jinlong; Wang, Liping

    2016-10-01

    In situ synchrotron x-ray diffraction experiments were conducted on 1,1-diamino-2,2-dinitroethylene (FOX-7) at pressures up to 6.8 GPa and temperatures up to 485 K. Within the resolution of the present diffraction data, our results do not reveal evidence for a pressure-induced structural phase transition near 2 GPa, previously observed in several vibrational spectroscopy experiments. Based on unit-cell volume measurements, the least-squares fit using the third-order Birch-Murnaghan equation of state (EOS) yields K 0  =  12.6  ±  1.4 GPa and K0\\prime   =  11.3  ±  2.1 for the α-phase of FOX-7, which are in good agreement with recently reported values for the deuterated sample, indicating that the effect of hydrogen-deuterium substitution on the compressibility of FOX-7 is negligibly small. A thermal EOS is also obtained for the α-phase of FOX-7, including pressure dependence of thermal expansivity, (∂α/∂P)T  =  -7.0  ±  2.0  ×  10-5 K-1 GPa-1, and temperature derivative of the bulk modulus, (∂K T/∂T)P  =  -1.1  ×  10-2 GPa K-1. From these EOS parameters, we calculate heat capacity at constant volume (C V) and thermodynamic Grüneisen parameter (γ TH) as a function of temperature. At ambient conditions, the calculated γ TH is 1.055, which is in good agreement with the value (1.09) previously obtained from density functional theory (DFT). The obtained C V, however, is 13% larger than that calculated from the first-principles calculations, indicating that the dispersion correction in the DFT calculations may need to be further improved for describing intermolecular interactions of molecular crystals.

  20. Synthesis and characterization of monoclinic rare earth titanates, RE2Ti2O7 (RE = La, Pr, Nd), by a modified SHS method using inorganic activator

    Indian Academy of Sciences (India)

    K Krishnankutty; K R Dayas

    2008-11-01

    The nano particles of phase pure rare earth titanates, synthesized by the SHS technique, get well sintered at lower temperatures compared to the compounds formed by the solid-state method. These dielectrics are highly stable and can be used in the microwave frequency range. We report here a modified SHS method to synthesize phase pure monoclinic RE2Ti2O7 at 350°C through the oxide/nitrate precursors using an inorganic compound, ammonium acetate, in place of the general type of organic activators such as urea, alanine etc. The nanopowders of La2Ti2O7, Pr2Ti2O7 and Nd2Ti2O7 on heating exhibit an exothermic behaviour with a broad maxima in the range 267–284°C and become endothermic with maxima in the range 1043–1220°C; interestingly, the phase pure crystalline material is formed at the temperature of exothermic maxima, as confirmed by XRD.

  1. The crystal structure and absolute configuration of the antitumor platinum complex trans(OH)-Pt(OH)2(malonato)(1R,2R-cyclohexanediamine).

    Science.gov (United States)

    Goto, M; Hirose, J; Noji, M; Lee, K I; Saito, R; Kidani, Y

    1992-04-01

    The absolute configuration of the anti-tumor complex trans(OH)-Pt(OH)2(malonato)(1R,2R-cyclohexanediamine) was determined by X-ray anomalous scattering technique. The final unit cell was monoclinic, space group P2(1) with a = 9.142 A, b = 7.788 A, c = 11.946 A, beta = 96.48 degrees, Z = 2. The crystal structure was determined by direct method and difference Fourier synthesis, and refined to R = 0.025 and Rw = 0.033 based on 2768 independent reflections. The platinum atom has roughly octahedral coordination. The cyclohexane ring has the expected chair configuration, with two amino groups in equatorial positions while the malonato ligand, in contrast, shows a boat conformation for six membered Pt O-C-C-C-O ring.

  2. Synthesis, Crystal Structure and Electrochemical Properties of a Cadmium(II) Complex with α-Furoic Acid and 1,10-Phenanthroline

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shao-Hua; LI Chang-Hong; LI Wei; YANG Ying-Qun

    2008-01-01

    A new cadmium complex [Cd(phen)3]·(ClO4)2·(α-FRA)·(H2O)3 was prepared by self-assembly of α-furoic acid, 1,10-phenanthroline (phen), and cadmium perchlorate. It crystal- lizes in the monoclinic system, space group P21/n, with a = 1.28130(15), b = 2.5957(3), c = 1.35449(16) nm, β = 109.395(2)o, V = 4.2492(9) nm3, Dc = 1.491 g/cm3, Z = 4, F(000) = 1926, GOOF = 1.023, the final R = 0.0729 and wR = 0.2086. The crystal structure analysis indicates that the cadmium ion is coordinated with six nitrogen atoms from six 1,10-phenanthroline molecules, giving a distorted octahedral coordination geometry. The cyclic voltametric behavior of the com- plex was also investigated.

  3. Reinvestigation on the Reaction of Salicylic Chloride with Salicylic Amide and X-ray Crystal Structure of a New Macrocyclic Polyester

    Institute of Scientific and Technical Information of China (English)

    DU Da-Ming; CHEN Xiao; HUA Wen-Ting; JIN Xiang-Lin

    2003-01-01

    The reaction of salicylic chloride and salicylic amide at 170 ℃ gave benzoxazine and a new macrocyclic polyester 3, whose crystal structure has been determined by single-crystal X-ray diffraction analysis. Compound 3: C28H16O8, Mr = 480.41, monoclinic, space group P21/n, a = 15.353(3), b = 14.196(3), c = 21.147(4) A, β = 103.32(3)°, V = 4485(2) A3, Z = 8, F(000) = 1984, Dc = 1.423 g/cm3 and μ = 0.106 mm-1. The final R = 0.0535 and Wr = 0.1275 for 7903 observed reflections (I ≥ 2σ(I)). In the asymmetric unit of the compound there exist two independent molecules which are connected by weak aromatic C-H…O hydrogen bonding between C(47)- H(47) and atom O(7) of the carbonyl group.

  4. Synthesis and Crystal Structure of Cis 2-(6- Chloro-3-pyridylmethylamino)-4-chlorophenyl-5,5-dimethyl-1,3,2-dioxaphosphinane 2-Oxides

    Institute of Scientific and Technical Information of China (English)

    刘漪; 魏佳; 石德清; 王成刚

    2005-01-01

    The crystal structure of the title compound (C17H19Cl2N2O3P, Mr= 401.21) has been determined by single-crystal X-ray diffraction. The crystal is of monoclinic, space group P21/n with a = 6.1648(6), b = 19.943(2), c = 15.268(2) (A),β = 99.220(2)°, V = 1852.8(3) (A)3, Z = 4, Dc = 1.438 g/cm3, F(000) = 832,μ(MoKa) = 0.456 mm-1, the final R = 0.0622 and wR = 0.1586 for 3986 observed reflections (I > 2σ(I)). X-ray analysis reveals that the product is a thermodynamically stable cis isomer. The intramolecular hydrogen bond N(2)-H(2A)…O(1) is observed in the title compound.

  5. Structural and magnetic phase transitions in Ca0.73Le0.27FeAs2 with electron-overdoped FeAs layers

    Science.gov (United States)

    Jiang, Shan; Liu, Chang; Cao, Huibo; Birol, Turan; Allred, Jared M.; Tian, Wei; Liu, Lian; Cho, Kyuil; Krogstad, Matthew J.; Ma, Jie; Taddei, Keith M.; Tanatar, Makariy A.; Hoesch, Moritz; Prozorov, Ruslan; Rosenkranz, Stephan; Uemura, Yasutomo J.; Kotliar, Gabriel; Ni, Ni

    2016-02-01

    We report a study of the Ca0.73La0.27FeAs2 single crystals. We unravel a monoclinic to triclinic phase transition at 58 K, and a paramagnetic to stripe antiferromagnetic phase transition at 54 K, below which spins order 45∘ away from the stripe direction. Furthermore, we demonstrate this material is substantially structurally untwinned at ambient pressure with the formation of spin rotation walls (S walls). Finally, in addition to the central-hole and corner-electron Fermi pockets usually appearing in Fe pnictide superconductors, angle-resolved photoemission measurements resolve a fermiology where an extra electron pocket of mainly As chain character exists at the Brillouin zone edge.

  6. Phase dependent structural and electronic properties of lanthanum orthophosphate (LaPO4)

    Science.gov (United States)

    Neupane, M. R.; Garrett, G. A.; Rudin, S.; Andzelm, J. W.

    2016-05-01

    We study the phase-dependent structural and electronic properties of bulk LaPO4, using density functional theory (DFT). The applicability of conventional semi-local and hybrid functionals in predicting structural and electronic properties of monoclinic and hexagonal LaPO4 is evaluated by comparing results to available experimental data. The monoclinic LaPO4 was found to be more stable than the hexagonal phase in ambient conditions with a small energy difference, suggesting a possibility of a phase transition. Both the phases in the bulk form are found to be diamagnetic with indirect energy gaps. These results are consistent with available experimental results. In the monoclinic phase, the hybrid functionals predict indirect band gap at about 8 eV. Furthermore, the calculated indirect-direct transition energy offset (ΔE) in the hexagonal phase was three times lower than the monoclinic phase. Our calculations based on hybrid functionals also reveal that the states near the conduction band edge in the hexagonal LaPO4 are strongly hybridized between La and PO4 states. By analyzing the band dispersion around the band edges, we show that the hexagonal phase has lighter electron effective mass, as compared to the monoclinic phase. With a larger energy gap, smaller ΔE, and smaller electron effective mass, the hexagonal LaPO4 might be a promising candidate material as an n-type transparent oxide.

  7. Supramolecular structure of S-(+)-marmesin-a linear dihydrofuranocoumarin

    Indian Academy of Sciences (India)

    Sanjeev Goswami; Vivek K Gupta; Ashok Sharma; B D Gupta

    2005-12-01

    The title compound, C14H14O4, a linear dihydrofuranocoumarin, was isolated from the bark of Aegle marmelos, a plant widely used in Ayurvedic system of medicine for the treatment of various ailments. The crystal structure was determined from X-ray diffraction data using direct methods. The compound crystallizes into monoclinic space group 21 with unit cell parameters: = 5.721(1) Å, = 13.810(1) Å, = 7.864(2) Å, = 100.39(1)°, = 2. The structure was refined by full-matrix least-squares to a final value of 0.0523 for 1184 observed reflections. The benzopyran moiety is perfectly planar. The dihedral angle between the pyrone and benzene rings is 0.3(1)°. The furan ring has a 2-envelope conformation. The molecules are linked by O–H…O hydrogen bonds into chains and these chains are linked into sheets by C–H…O hydrogen bonds. Further, the − stacking and C–H$\\ldots\\pi$(arene) interactions link all of the sheets into a supramolecular structure.

  8. Structural studies of disordered Mg2NiH4 formed by mechanical grinding

    DEFF Research Database (Denmark)

    Rönnebro, Ewa; Jensen, Jens Oluf; Noréus, Dag;

    1999-01-01

    The low temperature phase of Mg2NiH4 was mechanically ground in argon atmosphere. The ordered monoclinic structure was destroyed to form the disordered cubic structure, previously only found above 510 K. With a Guinier-Hagg X-ray camera the cell parameter was determined to be a=6.492(3) Angstrom....

  9. Structural characterization and catalytic properties of bis(1,1,3,3-tetramethylguanidinium) dichromate

    DEFF Research Database (Denmark)

    Due-Hansen, Johannes; Ståhl, Kenny; Boghosian, Soghomon

    2011-01-01

    The structure of bis(1,1,3,3-tetramethylguanidinium) dichromate was determined from powder X-ray diffraction data. The compound crystallizes in the monoclinic system (space group P21/n) with a = 10.79714 (15) Å, b = 11.75844 (16) Å, c = 8.15097 (11) Å, β = 109.5248 (6)º. The structure consists of...

  10. Synthesis and Crystal Structure of a Novel Ethyl 5-(4-(2-Phenylacetamido)phenyl)-lH-pyrazole- 3-carboxylate as an Acrosin Inhibitor%Synthesis and Crystal Structure of a Novel Ethyl 5-(4-(2-Phenylacetamido)phenyl)-lH-pyrazole- 3-carboxylate as an Acrosin Inhibitor

    Institute of Scientific and Technical Information of China (English)

    QI Jing-Jing; ZHOU You-Jun; LIU Xue-Fei; DING Li-Li; ZHENG Can-Hui; SHENG Chun-Quan; LV Jia-Guo; ZHU Ju

    2011-01-01

    The title compound (ethyl5-(4-(2-phenylacetamido)phenyl)-lH-pyrazole-3-carboxylate, C20H19N3O3) was synthesized by the reaction of Claisen condensation, cyclization, reduction and acylation. The structure was characterized by X-ray diffraction, MS, NMR and IR. It belongs to the monoclinic system, space group C2/c with a = 22.723(9), b = 9.324(4), c = 18.890(8) A, β = 114.259(6)°, V = 3649(3) A^3, Dc = 1.272 Mg·m^3, Z = 8, Mr = 349.38, p = 0.087 mm^-1, F(000) = 1472, the final R = 0.0615 and wR = 0.1643. The biological test shows that the title compound has a moderate acrosin inhibition activity.

  11. Modular fabrication and characterization of complex silicon carbide composite structures Advanced Reactor Technologies (ART) Research Final Report (Feb 2015 – May 2017)

    Energy Technology Data Exchange (ETDEWEB)

    Khalifa, Hesham [General Atomics, San Diego, CA (United States)

    2017-08-03

    Advanced ceramic materials exhibit properties that enable safety and fuel cycle efficiency improvements in advanced nuclear reactors. In order to fully exploit these desirable properties, new processing techniques are required to produce the complex geometries inherent to nuclear fuel assemblies and support structures. Through this project, the state of complex SiC-SiC composite fabrication for nuclear components has advanced significantly. New methods to produce complex SiC-SiC composite structures have been demonstrated in the form factors needed for in-core structural components in advanced high temperature nuclear reactors. Advanced characterization techniques have been employed to demonstrate that these complex SiC-SiC composite structures provide the strength, toughness and hermeticity required for service in harsh reactor conditions. The complex structures produced in this project represent a significant step forward in leveraging the excellent high temperature strength, resistance to neutron induced damage, and low neutron cross section of silicon carbide in nuclear applications.

  12. Defining the Interactions of Cellobiohydrolase with Substrate through Structure Function Studies: Cooperative Research and Development Final Report, CRADA Number CRD-10-409

    Energy Technology Data Exchange (ETDEWEB)

    Beckham, G. T.; Himmel, M. E.

    2013-07-01

    NREL researchers will use their expertise and skilled resources in numerical computational modeling to generate structure-function relationships for improved cellulase variant enzymes to support the development of cellulases with improved performance in biomass conversion.

  13. Long-term Bat Monitoring on Islands, Offshore Structures, and Coastal Sites in the Gulf of Maine, mid-Atlantic, and Great Lakes—Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, Trevor [Stantec Consulting Services Inc., Topsham, ME (United States); Pelletier, Steve [Stantec Consulting Services Inc., Topsham, ME (United States); Giovanni, Matt [Stantec Consulting Services Inc., Topsham, ME (United States)

    2016-01-15

    This report summarizes results of a long-term regional acoustic survey of bat activity at remote islands, offshore structures, and coastal sites in the Gulf of Maine, Great Lakes, and mid-Atlantic coast.

  14. Final Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Josef Michl

    2011-10-31

    In this project we have established guidelines for the design on organic chromophores suitable for producing high triplet yields via singlet fission. We have proven their utility by identifying a chromophore of a structural class that had never been examined for singlet fission before, 1,3-diphenylisobenzofuran, and demonstrating in two independent ways that a thin layer of this material produces a triplet yield of 200% within experimental error. We have also designed a second chromophore of a very different type, again of a structural class that had not been examined for singlet fission before, and found that in a thin layer it produces a 70% triplet yield. Finally, we have enhanced the theoretical understanding of the quantum mechanical nature of the singlet fission process.

  15. Magnetic and crystal structure refinement in akaganeite nanoparticle

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, K.E. [Grupo de Corrosion y Proteccion, Facultad de Ingenierias, Universidad de Antioquia. A.A. 1226, Medellin (Colombia); Morales, A.L. [Grupo de Corrosion y Proteccion, Facultad de Ingenierias, Universidad de Antioquia. A.A. 1226, Medellin (Colombia); Grupo de Estado Solido, Instituto de Fisica, Universidad de Antioquia. A.A. 1226, Medellin (Colombia); Barrero, C.A. [Grupo de Corrosion y Proteccion, Facultad de Ingenierias, Universidad de Antioquia. A.A. 1226, Medellin (Colombia) and Grupo de Estado Solido, Instituto de Fisica, Universidad de Antioquia. A.A. 1226, Medellin (Colombia)]. E-mail: cbarrero@fisica.udea.edu.co; Arroyave, C.E. [Grupo de Corrosion y Proteccion, Facultad de Ingenierias, Universidad de Antioquia. A.A. 1226, Medellin (Colombia); Greneche, J.M. [Laboratoire de Physique de l' Etat Condense-UMR 6087, Universite du Maine, 72085, Le Mans Cedex 9 (France)

    2004-12-31

    Preliminary assignments of the low-temperature Moessbauer signals obtained by taking into account a monoclinic structure for the akaganeite are presented. A powder sample was prepared by thermal hydrolysis of 0.1 M FeCl{sub 3} solutions at 70 deg. C during 48 h according to the literature. X-ray diffraction demonstrates the purity of the synthetic sample. The X-ray pattern was adequately adjusted by using the monoclinic space group (C2/m:b3) with a=10.5422(6) A, b=3.0349(1) A, c=10.5259(6) A and {beta}=90.1133(5) deg. The average grain size is estimated to be about 46(6) nm. The monoclinic symmetry requires the existence of two distinct iron octahedral sites, which is also confirmed by the Moessbauer spectra in the paramagnetic state. However, detailed computer analysis of Moessbauer spectra in the magnetic state suggests the presence of four non-equivalent iron sites. The physical origin of these different components in the magnetic region is discussed based upon the monoclinic structure.

  16. Synthesis and Crystal Structure of a Novel Hetero-bimetallic Complex with a Three-dimensional Network Structure: Bis(malonato)tetra(aqua)calcum(Ⅱ)cobalt(Ⅱ)

    Institute of Scientific and Technical Information of China (English)

    FU Xu-Cheng; NIE Li; ZHANG Qiang; LI Ming-Tian; WANG Xiao-Yan

    2006-01-01

    The title complex [CaCo(C3H2O4)2(H2O)4]n with a formula of C6H12CaCoO12 and Mr = 375.17 has been synthesized and structurally characterized by X-ray diffraction. The crystal is of monoclinic, space group C2/c with a = 14.195(9), b = 7.708(5), c = 13.441(8) (A),β = 119.575(9)°,V = 1279.0(14)(A)3, Dc = 1.948 g/cm3, μ = 1.803 mm-1, F(000) = 764 and Z = 4. The final R =0.0245 and wR = 0.0652 for 1344 observed reflections with I > 2o(I). The structure of the title complex consists of CaO8 polyhedra and CoO6 octahedra linked together by malonate ligands. The Ca(Ⅱ) cation on a twofold axis is coordinated by two water molecules and six malonate O atoms.The Co(Ⅱ) cation which lies in a centre of symmetry in an octahedral arrangement is coordinated by four malonate O atoms and two water molecules. The structure comprises alternating layers along the [101] plane, with the shortest Co-Co distance of 6.961(5) (A). The whole 3D structure is maintained and stabilized by the presence of hydrogen bonds.

  17. Structural studies of CsKBi mixed chlorides relation to the crystal structures of A2BMX6, A3MX6, and A2MX6

    Science.gov (United States)

    Benachenhou, Farida; Mairesse, Gaëtan; Nowogrocki, Guy; Thomas, Daniel

    1986-11-01

    The room-temperature crystal structures of Cs 3BiCl 6(I) and CsK 2BiCl 6(II) have been determined from X-ray single-crystal data. These compounds are both monoclinic, space group {C2}/{c}, with eight formula units per cell and cell parameters a = 27.017(17), b = 8.252(8), c = 13.121(10) Å, β = 99.70(11)° (I), a = 25.653(13), b = 7.799(5), c = 12.874(9) Å, β = 99.24(8)° (II). The crystal structures have been refined to final R values of 0.069(I) and 0.044(II) from 1706(I) and 2008(II) independent reflections and 93 variable parameters. The BiCl 6 octahedra are slightly distorted (average dBiCl = 2.699 Å) and the alkaline cations are coordinated with eleven or eight chlorine atoms. These structures are better described using the notion of "layers of close-packed octahedra" and can therefore be easily compared with the A2BMX6 (elpasolite type), A3MX6 (cryolite type), and A2MX6 (K 2PtCl 6 type) crystal structures. In these compounds, the "layers" of isolated octahedral MX6 entities ( X = F, Cl, Br, O) define "tetrahedral" and "octahedral" holes, entirely or partially occupied by the A and/or B cations.

  18. Synthesis and Crystal Structure of a 3-D Hydrogen-bonded Supramolecular Decavanadate Compound [Habo]6[V10O28]·2C3H7OH·2H2O

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A new inorganic-organic hybrid supramolecular compound [Habo]6[V10O28]·solvents and its crystal structure was reported as follows: monoclinic, space group P21/n, a =11.419(9), b = 16.811(16), c = 15.521(12) (A), β= 102.98(2)°, V= 2903(4) (A)3, Z = 4, C15H46N3O19V5,Mr = 827.25, Dc = 1.893 g/cm3, λ(MoKα) = 0.71073 A,μ = 1.636 mm-1, F(000) = 1696, the final R =0.0696 and wR = 0.1361 for 4641 observed reflections with I > 2σ(I). The compound is based on decavanadate clusters [V 1oO28]6-. The hydrogen bonding interactions among Habo+ cations, solvents and decavanadate clusters extend 1 into a three-dimensional supramolecular architecture.

  19. The structural and magnetic phase transitions in Ca{sub 0.73}La{sub 0.27}FeAs{sub 2} with electron overdoped FeAs layers.

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Shan; Liu, Chang; Cao, H.; Birol, Turan; Allred, Jared M.; Tian, Wei; Liu, Lian; Cho, Kyuil; Krogstad, Matthew J.; Ma, Jie; Taddei, Keith M.; Rosenkranz, Stephan

    2016-02-26

    We report a study of the Ca0.73La0.27FeAs2 single crystals. We unravel a monoclinic to triclinic phase transition at 58 K, and a paramagnetic to stripe antiferromagnetic (AFM) phase transition at 54 K, below which spins order 45° away from the stripe direction. Furthermore, we demonstrate this material is substantially structurally untwinned at ambient pressure with the formation of spin rotation walls (S-walls). Finally, in addition to the central-hole and corner-electron Fermi pockets usually appearing in FPS, angle-resolved photoemission (ARPES) measurements resolve a Fermiology where an extra electron pocket of mainly As chain character exists at the Brillouin zone edge.

  20. Crystal Structure and Characterization of the Dinuclear Cd(II Complex [Cd(H2O2(ο-HOC6H4COO2]2

    Directory of Open Access Journals (Sweden)

    Pusu Zhao

    2004-09-01

    Full Text Available The structure of a new binuclear cadmium (II complex, [Cd(H2O2(Sal2]2 (Sal= salicylate, has been determined by X-ray crystallography. It was also characterized byelemental analysis, its IR spectrum and thermogravimetric-differential scanningcalorimetry (TG-DSC. It crystallizes in the monoclinic system, space group P21/c, withlattice parameters a = 15.742(3 å, b = 12.451(3 å, c = 7.7225(15 å, β = 96.07(3o andZ = 4. Two cadmium (II ions are bridged by two μ2-carboxy oxygen atoms. Eachcadmium atom lies in a distorted capped octahedron coordination geometry. The thermalgravimetry (TG data indicate that there are four discrete decomposition steps with twoendothermic peaks and one exothermic peak. The final thermal decomposition product isCdO.

  1. 一种镧系-过渡金属二维氰桥配合物[Nd(DMSO)2(H2O)2][Ni(CN)4]Cl(DMSO=二甲亚砜)的合成和晶体结构%Synthesis and Crystal Structure of a Cyano-Bridged Lanthanide-Transition-Metal Complex [Nd(DMSO)2(H2O)2][Ni(CN)4]Cl (DMSO=Dimethylsulfoxide) with Two-dimensional Gridding Molecule Structure

    Institute of Scientific and Technical Information of China (English)

    梁淑惠; 车云霞; 郑吉民

    2005-01-01

    The cyano-bridged bimetallic complex [Nd(DMSO)2(H2O)2][Ni(CN)4]Cl with two-dimensional gridding molecule structure was synthesized and characterized. In the complex all four cyano groups of unit Ni(CN)42- are bound to Nd3+ ions. The crystal data for the title complex: monoclinic, space group P21/c, a=0.780 0(3) nm,b=1.5097(6) nm, c=1.683 2(6) nm, β=115.231(14)°, Z=4, μ=4.311 mm-1, final R1=0.020 9, wR2=0.045 4. CCDC:272214.

  2. Crystal Structure of 3S-hydroxy-7 Melleine

    Science.gov (United States)

    Liu, Xiao-hong; Xu, Fang; Zhang, Yi; Liu, Li-hong; Huang, Hua-rong; She, Zhi-gang; Lin, Yong-cheng; Chan, Winglai

    2006-10-01

    A new compound, 3S-hydroxy-7 melleine was isolated from the endophytic fungus Xylariasp No.2508 from the mangrove tree on the South China Sea coast. It was the first time that this kind of compound was isolated from marine fungus. The structure was elucidated by NMR data, infrared spectrum (IR) and mass spectrometry (MS). In addition, its structure was determined by the single-crystal X-ray diffraction analysis. It crystallized in monoclinic, space group P21 with a=10.8884(19) Å, b=7.2284(13) Å, c=13.398(2) Å, β=104.217(3)°, C10H10O4·H2O, Mr=212.20, V=1022.2(3) Å3, Z=4, Dc=1.379 mg/m3, F(000)=448, μ=0.112 mm-1, the final R=0.0498, ωR=0.101 for 2407 observed reflections (I>2σ(I)). The molecular backbone of the compound includes a benzopyran ring. By comparing with the melting point and the optical rotation of the known 3R-hydroxy-7 melleine in literature, the absolute configuration of the compound was determined as 3S. It didn't exhibit antibacterial activity against Gram-positive bacterium Staphylococcus aureus at 200 μg/disk in the preliminary test.

  3. National Academy of Sciences and Academy of Sciences of the USSR workshop on structure of the eucaryotic genome and regulation of its expression. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1990-12-31

    This report provides a brief overview of the Workshop on Structure of the Eukaryotic Genome and Regulation of its Expression held in Tbilisi, Georgia, USSR. The report describes the presentations made at the meeting but also goes on to describe the state of molecular biology and genetics research in the Soviet Union and makes recommendations on how to improve future such meetings.

  4. The Effect of Repeated Listenings on Ability to Recognize the Structural Elements of Music and the Influence of this Ability on Affective Shift. Final Report.

    Science.gov (United States)

    Bartlett, Dale L.

    This study, conducted over a period of three weeks at the University of Kansas, attempted to determine whether knowledge of musical structure would effect greater understanding and, eventually, enjoyment of music. Experimental and control groups comprising freshmen who were not enrolled in a music course listened repeatedly to excerpts of…

  5. The New Superconductor tP-SrPd2Bi2: Structural Polymorphism and Superconductivity in Intermetallics.

    Science.gov (United States)

    Xie, Weiwei; Seibel, Elizabeth M; Cava, Robert J

    2016-04-01

    We consider a system where structural polymorphism suggests the possible existence of superconductivity through the implied structural instability. SrPd2Bi2 has two polymorphs, which can be controlled by the synthesis temperature: a tetragonal form (CaBe2Ge2-type) and a monoclinic form (BaAu2Sb2-type). Although the crystallographic difference between the two forms may, at first, seem trivial, we show that tetragonal SrPd2Bi2 is superconducting at 2.0 K, whereas monoclinic SrPd2Bi2 is not. We rationalize this finding and place it in context with other 1-2-2 phases.

  6. Electric field induced cubic to monoclinic phase transition in multiferroic 0.65Bi(Ni{sub 1/2}Ti{sub 1/2})O{sub 3}-0.35PbTiO{sub 3} solid solution

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Rishikesh; Singh, Akhilesh Kumar, E-mail: akhilesh-bhu@yahoo.com [School of Materials Science and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India)

    2014-10-20

    The results of x-ray diffraction studies on 0.65Bi(Ni{sub 1/2}Ti{sub 1/2})O{sub 3}-0.35PbTiO{sub 3} solid solution poled at various electric fields are presented. After poling, significant value of planar electromechanical coupling coefficient (k{sub P}) is observed for this composition having cubic structure in unpoled state. The cubic structure of 0.65Bi(Ni{sub 1/2}Ti{sub 1/2})O{sub 3}-0.35PbTiO{sub 3} transforms to monoclinic structure with space group Pm for the poling field ≥5 kV/cm. Large c-axis microscopic lattice strain (1.6%) is achieved at 30 kV/cm poling field. The variation of the c-axis strain and unit cell volume with poling field shows a drastic jump similar to that observed for strain versus electric field curve in (1 − x)Pb(Mg{sub 1/3}Nb{sub 2/3}) O{sub 3}-xPbTiO{sub 3} and (1 − x)Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3}-xPbTiO{sub 3}.

  7. About lamination upper and convexification lower bounds on the free energy of monoclinic shape memory alloys in the context of T 3-configurations and R-phase formation

    Science.gov (United States)

    Fechte-Heinen, R.; Schlömerkemper, A.

    2016-11-01

    This work is concerned with different estimates of the quasiconvexification of multi-well energy landscapes of NiTi shape memory alloys, which models the overall behavior of the material. Within the setting of the geometrically linear theory of elasticity, we consider a formula of the quasiconvexification which involves the so-called energy of mixing.We are interested in lower and upper bounds on the energy of mixing in order to get a better understanding of the quasiconvexification. The lower bound on the energy of mixing is obtained by convexification; it is also called Sachs or Reuß lower bound. The upper bound on the energy of mixing is based on second-order lamination. In particular, we are interested in the difference between the lower and upper bounds. Our numerical simulations show that the difference is in fact of the order of 1% and less in martensitic NiTi, even though both bounds on the energy of mixing were rather expected to differ more significantly. Hence, in various circumstances it may be justified to simply work with the convexification of the multi-well energy, which is relatively easy to deal with, or with the lamination upper bound, which always corresponds to a physically realistic microstructure, as an estimate of the quasiconvexification. In order to obtain a potentially large difference between upper and lower bound, we consider the bounds along paths in strain space which involve incompatible strains. In monoclinic shape memory alloys, three-tuples of pairwise incompatible strains play a special role since they form so-called T 3-configurations, originally discussed in a stress-free setting. In this work, we therefore consider in particular numerical simulations along paths in strain space which are related to these T 3-configurations. Interestingly, we observe that the second-order lamination upper bound along such paths is related to the geometry of the T 3-configurations. In addition to the purely martensitic regime, we also consider

  8. Molecular salts of 2,6-dihydroxybenzoic acid (2,6-DHB) with N-heterocycles: Crystal structures, spectral properties and Hirshfeld surface analysis

    Science.gov (United States)

    Solomon, K. Anand; Blacque, Olivier; Venkatnarayan, Ramanathan

    2017-04-01

    In the present study, two molecular complexes of 2,6-DHB with pharmaceutically active nutraceuticals i.e. nicotinic acid (NA) and nicotinamide (NIC) have been synthesized and preliminarily characterized by powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC) and FT-IR spectroscopy. Finally the crystal structures were solved by single crystal X-ray diffraction and the structures were analyzed in terms of supramolecular interactions. The salt 1 crystallizes in the monoclinic space group Cc, with a = 10.1503(1) Å, b = 12.3821(1) Å, c = 9.5291(1) Å, β = 94.343(1)°, V = 1194.20(2) Å3, Z = 4. The salt 2 crystallizes in monoclinic space group P21/n, with a = 7.0098 (1) Å, b = 12.5495 (1) Å, c = 13.4048 (1) Å, β = 92.746 (1)°, V = 1177.86 (2) Å3, Z = 4. The molecular packing of both salts are stabilized by N+-H⋯O-, O-H⋯O-, N-H⋯O and O-H⋯O hydrogen bonding interactions. DFT calculations substantiate the features of crystal structures. The Hirshfeld surfaces and the associated 2D fingerprint plots were investigated which revealed that more than two-third of close contacts were associated with relatively weak H⋯H, C⋯H and H⋯C interactions. The use of 3-D Hirshfeld surfaces in combination with 2-D fingerprint plots revealed that these weak interactions play major role in molecular crystal packing.

  9. Contamination of dental zirconia before final firing: effects on mechanical properties.

    Science.gov (United States)

    Ban, Seiji; Okuda, Yuji; Noda, Makoto; Tsuruki, Jiro; Kawai, Tatsushi; Kono, Hiroshi

    2013-01-01

    Plate-like specimens were prepared, using a diamond saw, from Cercon -a pre-sintered yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) block. These specimens were treated with 10 kinds of dental materials which acted as contaminants, and then sintered at 1,350°C or 1,450°C. After the final firing, specimens were subjected to a three-point flexural test and Vickers hardness test. Their surfaces were also characterized by scanning electron microscopy and X-ray diffractometry. Phosphorus-containing contaminants reduced the three-point flexural strength and hardness of final sintered zirconia due to the formation of YPO4 and phase transformation from tetragonal to monoclinic zirconia. Gypsum also reduced both mechanical properties due to the formation of CaZrO3 and phase transformation from tetragonal to cubic zirconia. Other contaminants showed no adverse effects on the mechanical properties of final sintered zirconia.

  10. Surface structure and hole localization in bismuth vanadate: A first principles study

    Science.gov (United States)

    Kweon, Kyoung E.; Hwang, Gyeong S.

    2013-09-01

    The monoclinic and tetragonal phases of bismuth vanadate (BiVO4) have been found to exhibit significantly different photocatalytic activities for water splitting. To assess a possible surface effect on the phase-dependent behavior, we calculate and compare the geometries and electronic structures of the monoclinic and tetragonal BiVO4 (001) surfaces using hybrid density functional theory. The relaxed atomic configurations of these two surfaces are found to be nearly identical, while an excess hole shows a relatively stronger tendency to localize at the surface than the bulk in both phases. Possible factors for the phase-dependent photocatalytic activity of BiVO4 are discussed.

  11. Synthesis, Structure and Characterization of a Cd(Ⅱ) Polymer Based on 6-Hydroxynicotinic Acid

    Institute of Scientific and Technical Information of China (English)

    HE Yin-Hua; GUO Zhi-Han; FENG Yun-Long

    2008-01-01

    A new 2D layered Cd(II) coordination polymer, [Cd(HnicO)(phen)(NO3)]n 1 (H2nicO = 6-hydroxynicotinic acid, phen = 1,10-phenanthroline), has been hydrothermally synthesized and characterized by elemental analysis, IR, and single-crystal X-ray diffraction.It crystallizes in the monoclinic system, space group P21/c with a = 11.1107(2), b = 13.7639(2), c = 12.1457(4) -, β = 108.695(1)°, V = 1759.40(7) -3, Z = 4, Mr = 492.72 , F(000) = 976, Dc = 1.860 g/cm3, μ = 1.289 mm-1, the final R = 0.0205 and wR = 0.0550 for 3663 observed reflections (I > 2σ(I)).X-ray single-crystal structural analyses reveal that in complex 1, the H2nicO ligands and Cd(II) nodes define the structure to be (4,4) 2D nets which are further assembled into the final 3D architecture via supramolecular interactions such as hydrogen bonds and aromatic interactions.Moreover, the solid-state luminescent study shows the title polymer possesses intense luminescent property at room temperature.

  12. Final Technical Report on DE-SC00002460 [Bimetallic or trimetallic materials with structural metal centers based on Mn, Fe or V

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, Esther Sans [Stony Brook University; Takeuchi, Kenneth James [Stony Brook University; Marschilok, Amy Catherine [Stony Brook University

    2013-07-26

    Bimetallic or trimetallic materials with structural metal centers based on Mn, Fe or V were investigated under this project. These metal centers are the focus of this research as they have high earth abundance and have each shown success as cathode materials in lithium batteries. Silver ion, Ag{sup +}, was initially selected as the displacement material as reduction of this center should result in increased conductivity as Ag{sup 0} metal particles are formed in-situ upon electrochemical reduction. The in-situ formation of metal nanoparticles upon electrochemical reduction has been previously noted, and more recently, we have investigated the resulting increase in conductivity. Layered materials as well as materials with tunnel or channel type structures were selected. Layered materials are of interest as they can provide 2-dimensional ion mobility. Tunnel or channel structures are also of interest as they provide a rigid framework that should remain stable over many discharge/charge cycles. We describe some examples of materials we have synthesized that demonstrate promising electrochemistry.

  13. Syntheses and Crystal Structures of 3,3'-(9,10-Anthrylene)bis-pentane-2,4-dione and 3-(2-Methoxy-1-naphthalenyl)-pentane-2,4-dione

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Two compounds 3,3'-(9,10-anthrylene)bis-pentane-2,4-dione 1 and 3-(2-methoxy-1-naphthalenyl)-pentane-2,4-dione 2 were synthesized by the direct arylation of pentane-2,4-diones in the presence of Mn(OAc)3 and H3PO4. Their crystal structures were determined by X-ray diffraction method. Compound 1, C24H22O4, Mr = 374.4, crystallized in the monoclinic system, space group P21/a with a = 7.393(4), b = 14.308(5), c = 10.099(5) ?, β = 110.8(4)o, V = 999.0 (9) ?3, Z = 2, Dc = 2.49g/cm3, F(000) = 392, μ = 0.78cm-1, final R = 0.050 and Rw = 0.057 for 1144 observed reflections with I≥3.00 σ (I). The molecular backbone is the anthracene ring, and two acetoacetone groups are perpendicular to the anthracene ring at 9,10 positions. Compound 2, C16H16O3, Mr = 256.3, crystallized in monoclinic system, space group C2 with a = 14.369(3), b = 7.480 (1), c = 15.878 (2) ?, β = 128.46(1)o, V = 1336.3(4) ?3, Z = 4, Dc = 1.27g/cm3, F(000) = 544, μ = 0.81cm-1. The structure was solved by direct methods and refined by full-matrix least-squares method, final R = 0.044 and Rw = 0.040 for 764 observed reflections with I ≥3.00σ(I). The acetoacetone group in compound 2 is also vertical to the naphthalene ring.

  14. Final Report Grant No. DE-FG02-98ER20307 Lipopolysaccharide Structures and Genes Required for Root Nodule Development August 1, 2004 to July 31, 2008

    Energy Technology Data Exchange (ETDEWEB)

    Noel, K. Dale [Marquette Univ., Milwaukee,WI (United States)

    2008-12-07

    This project dealt with the plant-bacterial symbiosis that gives rise to root nodules on leguminous plants in which the bacteria carry out nitrogen fixation. Nitrogen fixation, like carbon dioxide fixation, is essential for life on planet earth, and this symbiosis is estimated to account for half of all nitrogen fixed on land. Aside from being important for the sustenance of global life, this ability allows legumes to grow without nitrogen fertilizers. Basic studies such as this project are aimed at understanding the symbiosis well enough that eventually it can be engineered into important crop species so that they no longer depend on nitrogen fertilizer for growth. The production and distribution of excessive fertilizer needed for optimal crop yields is responsible for a significant portion of the energy costs in agriculture. The specific aims of this work were to further the understanding of a bacterial factor that is essential for the symbiotic infection process. This factor is a bacterial surface molecule, lipopolysaccharide O antigen. In this project we showed that, not only the presence, but the specific structure of this molecule is crucial for infection. Although the success of bacterial infections in many pathogenic and mutualistic interactions have been shown to depend on intact O antigen, it has been very rare to establish that specific features of the structure are important. One of the features in this case is the presence of one additional methyl group on one sugar in the O antigen. It is very surprising that such a minor change should have an observable effect. This work sets the stage for biochemical studies of possible plant receptors that may be involved. During the course of this grant period, we developed a method of testing the importance of this bacterial component at stages of nodule development beyond the step that is blocked by null mutation. The method works adequately for this purpose and is being improved. It has implications for testing

  15. Crystal structure and infrared spectrum of thallium holmium polyphosphate, TIHo(PO3)4

    Institute of Scientific and Technical Information of China (English)

    Karima Horchani-Naifer; Jaouher Amami; Mokhtar Ferid

    2008-01-01

    Crystals of thallium-holmium polyphosphate TIHo(PO3)4 were grown by flux method technique and characterized by single crystal X-ray diffraction. Structure of TIHo(PO3)4 was solved for the first time, and it crystallized in the monoclinic P21/n space group with the following unit-cell dimensions: a=1.02225(3) nm, b=0.88536(2) nm, c=1.09541(4) nm, β=105.888(1)°, V=0.95354(5) nm3 and Z=4. The crystal structure was solved from 2174 independent reflections with final R1(F2)=0.0442 and Rw(F<2)=0.0861 refined with 164 parameters. The atomic arrangement could be described as a long chain polyphosphate organization. Holmium atoms had eighffold coordination. The structure of T1Ho(PO3)4 consisted of HoO8 polyhedra sharing oxygen atoms with phosphoric group PO4. Infrared spectrum was investigated at room temperature in the frequencies range, 350-4000 cm-1, showing some characteristic vibration bands of infinite chain structure of PO4 tetrahedra linked by bridging oxygen.

  16. Crystal structure of nitarsone determined from synchrotron X-ray powder diffraction data

    Science.gov (United States)

    van der Lee, A.; Richez, P.; Tapiero, C.

    2005-05-01

    The crystal structure of nitarsone, 4-nitrophenylarsonic acid, a substitute for nifursol and dimetridazole in the prevention and treatment of turkey histomoniasis desease, has been determined from synchrotron X-ray powder diffraction data. Nitarsone crystallizes in the monoclinic space group P2 1/ n with unit cell parameters a=7.46413(5), b=25.68543(17), c=4.657388(32) Å, β=105.4670(5)°. The structure was solved using simulated annealing techniques by treating the molecule as a rigid body for which the configuration resulting from an energy minimization was used in slightly adapted form. Structure refinement treated the NO 2 and the AsO(OH) 2 groups as free groups, leading to final confidence factors Rp=0.059 and Rwp=0.071. The crystal structure contains 4 molecules per unit cell that are hydrogen bonded to form infinite chains of dimers running along the c-axis. Nitarsone's low toxicity when compared with inorganic sources of arsenic is explained by the existence of a partial double C-As bond (1.866(5) Å) which confers greater stability so that under physiological conditions nitarsone is not converted to mineral-like As V or III.

  17. Synthesis, Structure and Biological Activities of Novel Triazole Compounds Containing N,N-Dialkyldithiocarbamate Moiety

    Institute of Scientific and Technical Information of China (English)

    XU,Liang-Zhong(许良忠); JIAN,Fang-Fang(建方方); SHI,Jian-Gang(时建刚); SUN,Ping-Ping(孙萍萍); JIAO,Kui(焦奎)

    2004-01-01

    The two compounds, 2,2-dimethyl-4-S-(N,N-dimethyldithiocarbamato)-5-(1,2,4-triazol-1-yl)-propione (1) and 2,2-dimethyl-4-S-(N,N-diethyldithiocarbamato)-5-(1,2,4-triazol-1-yl)-3-propione (2), were prepared by reacting N,N-dialkyldithiocarbamate sodium with 2,2-dimethyl-4-bromo-5-(1,2,4-triazol-1-yl)-propione. Their structures were identified by elemental analysis, IR and 1H NMR spectroscopy. The structure of 1 has been determined by X-ray single crystal structure analysis. It crystallizes in monoclinic system with space group P21/c, a= 1.2315(3)nm, b =1.2057(2) nm, c=1.2532(3) nm, β=118.55(3)° Z=4, V= 1.6345(6) nm3, Dc= 1.221 g/cm3, μ=0.324 mm -1, F(000)=640, final R1 =0.0449. There is obvious potentially weak C-H…N intermolecular interaction in the crystal, which stabilizes the crystal structure. The result of the biological test showed that the two compounds have fungistasis and plant growth regulating activities.

  18. Crystal structure and chemical bonding of the high-temperature phase of AgN3.

    Science.gov (United States)

    Schmidt, Carsten L; Dinnebier, Robert; Wedig, Ulrich; Jansen, Martin

    2007-02-05

    The crystal structure of silver azide (AgN3) in its high-temperature (HT) modification was determined from X-ray powder diffraction data, recorded at T = 170 degrees C and was further refined by the Rietveld method. The structure is monoclinic (P21/c (No. 14), a = 6.0756(2) A, b = 6.1663(2) A, c = 6.5729(2) A, beta = 114.19(0) degrees, V = 224.62(14) A3, Z = 4) and consists of two-dimensional Ag and N containing layers in which the silver atoms are coordinated by four nitrogen atoms exhibiting a distorted square coordination environment. These sheets are linked together by weaker perpendicular Ag-N contacts, thus forming a 4 + 2 coordination geometry around the silver atoms. The phase transition has been characterized by DTA, DSC, and measurement of the density, as well as of the ionic conductivity. Both, the room-temperature and the HT phase are electrically insulating. This fact is getting support by DFT band structure calculations within the generalized gradient approximation, using the PBE functional. On the basis of the DFT band structure, the bonding characteristics of both phases are essentially the same. Finally, the implication of the existence of a low-symmetry HT-phase in a crystalline explosive concerning decomposition mechanisms is discussed.

  19. Crystal Structure and Chemical Bonding of the High-Temperature Phase of AgN3

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt,C.; Dinnebier, R.; Wedig, U.; Jansen, M.

    2007-01-01

    The crystal structure of silver azide (AgN{sub 3}) in its high-temperature (HT) modification was determined from X-ray powder diffraction data, recorded at T = 170 {sup o}C and was further refined by the Rietveld method. The structure is monoclinic (P2{sub 1}lc (No. 14), a = 6.0756(2) {angstrom}, b = 6.1663(2) {angstrom}, c = 6.5729(2) {angstrom}, {beta} = 114.19(0){sup o}, V = 224.62(14) {angstrom}{sup 3}, Z = 4) and consists of two-dimensional Ag and N containing layers in which the silver atoms are coordinated by four nitrogen atoms exhibiting a distorted square coordination environment. These sheets are linked together by weaker perpendicular Ag-N contacts, thus forming a 4 + 2 coordination geometry around the silver atoms. The phase transition has been characterized by DTA, DSC, and measurement of the density, as well as of the ionic conductivity. Both, the room-temperature and the HT phase are electrically insulating. This fact is getting support by DFT band structure calculations within the generalized gradient approximation, using the PBE functional. On the basis of the DFT band structure, the bonding characteristics of both phases are essentially the same. Finally, the implication of the existence of a low-symmetry HT-phase in a crystalline explosive concerning decomposition mechanisms is discussed.

  20. The influence of the final cause doctrine on anatomists of the sixteenth and seventeenth centuries concerning selected anatomical structures of the head and neck.

    Science.gov (United States)

    Lydiatt, Daniel D; Bucher, Gregory S

    2012-09-01

    The Doctrine of Final Cause, taken from Aristotle's "causes" and modified by Claudius (Aelius) Galen (of Pergamon) stated that for an anatomical part to exist it must have a "cause," not an end point, but a purpose or goal, natural or divine. This affected the renaissance anatomist's thinking. We explore this doctrine's relationship with human head and neck anatomy from antiquity's Aristotle and Galen, and the leading renaissance anatomists from the 16th and 17th centuries. Their relevant writings were influenced by religious and political beliefs and varied from humanistic to reactionary. Tracing anatomical controversies through these works reveal the humanism of Vesalius and others as paralleling the humanists of art and literature. These controversies illustrate how the body was used to demonstrate function, uses, and causes from higher sources. Humanists advanced the social, philosophical, intellectual, literary, and medical/anatomical thoughts of this period. They stood between the Christian church of the Middle Ages and modern science. Like religion, medicine and anatomy had its own revealed sources of knowledge and had sacred texts like Galen's. Vesalius' the Fabrica and the woodcuts established suddenly the beginning of modern observational science and art as the direct and faithful representation of natural phenomena. They displayed anatomy such that others could understand, including errors of Galen, bringing Vesalius into ecclesiastical conflict. Evolutionary scientists today see mutations as favorable or unfavorable depending on the environment. Mutations are random or directed by divine plan, according to perspectives of this ancient debate. Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc.

  1. Development of improved processing and evaluation methods for high reliability structural ceramics for advanced heat engine applications, Phase 1. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Pujari, V.K.; Tracey, D.M.; Foley, M.R.; Paille, N.I.; Pelletier, P.J.; Sales, L.C.; Wilkens, C.A.; Yeckley, R.L. [Norton Co., Northboro, MA (United States)

    1993-08-01

    The program goals were to develop and demonstrate significant improvements in processing methods, process controls and non-destructive evaluation (NDE) which can be commercially implemented to produce high reliability silicon nitride components for advanced heat engine applications at temperatures to 1,370{degrees}C. The program focused on a Si{sub 3}N{sub 4}-4% Y{sub 2}O{sub 3} high temperature ceramic composition and hot-isostatic-pressing as the method of densification. Stage I had as major objectives: (1) comparing injection molding and colloidal consolidation process routes, and selecting one route for subsequent optimization, (2) comparing the performance of water milled and alcohol milled powder and selecting one on the basis of performance data, and (3) adapting several NDE methods to the needs of ceramic processing. The NDE methods considered were microfocus X-ray radiography, computed tomography, ultrasonics, NMR imaging, NMR spectroscopy, fluorescent liquid dye penetrant and X-ray diffraction residual stress analysis. The colloidal consolidation process route was selected and approved as the forming technique for the remainder of the program. The material produced by the final Stage II optimized process has been given the designation NCX 5102 silicon nitride. According to plan, a large number of specimens were produced and tested during Stage III to establish a statistically robust room temperature tensile strength database for this material. Highlights of the Stage III process demonstration and resultant database are included in the main text of the report, along with a synopsis of the NCX-5102 aqueous based colloidal process. The R and D accomplishments for Stage I are discussed in Appendices 1--4, while the tensile strength-fractography database for the Stage III NCX-5102 process demonstration is provided in Appendix 5. 4 refs., 108 figs., 23 tabs.

  2. Syntheses and Crystal Structures of Pyrazoline Derivants

    Institute of Scientific and Technical Information of China (English)

    SHI Hai-Bin; JI Shun-Jun; ZHANG Yong

    2005-01-01

    Two pyrazoline derivants 1-(2-benzothiazole)-3-phenyl-5-(3-thiophene)-2- pyrazoline (BPTP) and 1-(2-benzothiazole)-3-(2-thiophene)-5-phenyl-2-pyrazoline (BTPP) have been synthe- sized and their crystal structures were determined by X-ray single-crystal diffraction.Crystal of BPTP belongs to triclinic, space group P with a = 9.4430(11), b = 9.9384(13), c = 9.9394(13) (A), α = 83.107(10), β = 79.947(10), γ = 70.221(7)o, V = 862.42(19) (A)3, Z = 2, Dc = 1.392 g/cm3, μ(MoKα) = 0.316 mm-1, F(000) = 376, λ = 0.71070 (A), (Δρ)max = 0.348, (Δρ)min = -0.481 e/(A)3, the final R = 0.0407 and wR = 0.1055 for 2844 observed reflections with I > 2σ(I).Crystal of BTPP is of monoclinic, space group P21/c with a = 11.6158(17), b = 11.2796(18), c = 13.082(2) (A), α = 90, β = 91.087(4), γ = 90o, V = 1713.7(5) (A)3, Z = 4, Dc = 1.401 g/cm3, μ(MoKα) = 0.318 mm-1, Mr = 361.07, F(000) = 752, λ = 0.71070 (A), (Δρ)max = 0.322, (Δρ)min = -0.330 e/(A)3, the final R = 0.0563 and wR = 0.1058 for 3434 observed reflections with I > 2σ(I).

  3. Morphological studies at subchondral bone structures in human early arthrosis. Final report; Morphologische Studien an subchondralen Knochenstrukturen bei humanen Frueharthrosen. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1992-12-31

    Quantitative histomorphometric studies using an image analysis system were performed simultaneously on hyaline cartilage, calcified cartilage and subchondral cancellous bone of human tibial heads for detailed information about the pathogenesis of arthrosis. Joint structures need to be fully detected in three dimensions since measurement values are more affected by topographical aspects than by either age, or sex, or arthrosin stage. Mechanical factors were found to affect essentially the initiation and progression of arthrosis. Results are demonstrated in detail. (orig.) [Deutsch] Um detaillierte Aussagen ueber die Pathogenese der Arthrose machen zu koennen, wurden hyaliner Knorpel, Kalkknorpel und subchondrale Spongiosa menschlicher Tibiakoepfe gleichzeitig mit Hilfe eines Bildanalysesystems quantitativ histomorphometrisch untersucht. Eine umfangreiche dreidimensionale Erfassung der Gelenkstrukturen ist erforderlich, da sich topographische Aspekte wesentlich staerker auf die Messwerte auswirken als Alter, Geschlecht oder Arthrosestadium. Insgesamt zeigt sich ein wesentlicher Einfluss mechanischer Faktoren auf die Arthroseinitiierung und -progredienz. Die Ergebnisse werden detailliert dargestellt. (orig.)

  4. Nanoconfinement crystallization of frustrated alkyl groups: crossover of mesophase to crystalline structure.

    Science.gov (United States)

    Shi, Haifeng; Wang, Haixia; Xin, John H; Zhang, Xingxiang; Wang, Dujin

    2011-04-07

    Crossover of mesophase to crystalline structure in the nanoconfinement crystallization process of frustrated side groups elucidates the critical crystal thickness d(c) or the length scale of side groups, which defines the transition process from mesophase (hexagonal and monoclinic phase) to crystalline phase (orthorhombic phase) of confined CH(2) sequences in a given crystal size restriction.

  5. The effect of tantalum and carbon on the structure/properties of a single crystal nickel-base superalloy. M.S. Thesis. Final Report

    Science.gov (United States)

    Nguyen, H. C.

    1984-01-01

    The microstructure, phase chemistry, and creep and hot tensile properties were studied as a function of tantalum and carbon levels in Mar-M247 type single crystal alloys. Microstructural studies showed that several types of carbides (MC, M23C6 and M5C) are present in the normal carbon (0.10 wt % C) alloys after heat treatment. In general, the composition of the MC carbides changes from titanium rich to tantalum rich as the tantalum level in the alloy increases. Small M23C6 carbides are present in all alloys. Tungsten rich M6C carbides are also observed in the alloy containing no tantalum. No carbides are present in the low carbon (0.01 wt % C) alloy series. The morphology of gamma prime is observed to be sensitive to heat treatment and tantalum level in the alloy. Cuboidal gamma prime is present in all the as cast structures. After heat treatment, the gamma prime precipitates tend to have a more spheroidal like morphology, and this tendency increases as the tantalum level decreases. On prolonged aging, the gamma prime reverts back to a cuboidal morphology or under stress at high temperatures, forms a rafted structure. The weight fraction and lattice parameter of the spheroidal gamma prime increases with increasing tantalum content. Changes in the phase chemistry of the gamma prime matrix and gamma prime have also been analyzed using phase extraction techniques. The partitioning ratio decreases for tungsten and aluminum and increases for tantalum as the tantalum content increases for both alloy series; no significant changes occur in the partitioning ratios of the other alloying elements. A reduction in secondary creep rate and an increase in rupture time result from increasing the tantalum content and decreasing the carbon level.

  6. Monoclinic form of (cyanato-κN{2,2′-[ethane-1,2-diylbis(nitrilomethylidyne]diphenolato-κ4O,N,N′,O′}manganese(III

    Directory of Open Access Journals (Sweden)

    Daopeng Zhang

    2010-12-01

    Full Text Available The title compound, [Mn(C16H14N2O2(NCO], is a monoclinic polymorph of the previously published orthorhombic form [Lu et al. (2006. Inorg. Chem. 45, 3538–3548]. The MnIII ion is chelated by a tetradentate Schiff base ligand and coordinated by the N atom of a cyanate ligand in a distorted square-pyramidal arrangement. In the crystal, there are short intermolecular Mn...Ophenolate distances of 2.752 (3 Å between pairs of inversion-related molecules.

  7. Structure of coal: new approaches to characterizing organonitrogen and organosulfur functionalities in coal and coal liquids. Final report. [Finnigan triple quadrupole mass spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Cooks, R.G.

    1983-01-01

    This report describes the application of tandem mass spectrometry (MS/MS) to the analysis of coal-related materials. A Finnigan Triple State Quadrupole mass spectrometer was used for most of the results obtained in this study. Both collision energy (0 to 30 eV) and collision gas pressure (0 to 2.5 mtorr, typically argon) have significant effects on the spectra. Increasing the collision energy or collision pressure results in an increased fragmentation of the selected ion. The analytical utility of different chemical ionization (CI) reagent gases is shown. The MS/MS spectra of a selected ion obtained by isobutane and ammonia CI are identical, which paves the way for development of MS/MS libraries. A library is being developed especially for the analysis of coal-related materials. Three principal MS/MS scan modes (daughter, parent and neutral loss) are utilized in the analysis of coal-related materials. Parent and neutral loss scans characterize the complex mixture for particular chemical moieties (functional groups, structure type), while daughter scans are used for identification of specific components. SRC II was the principal sample studied by CI. Laser desorption methodology for coal analysis was developed. Other fuel-related materials were examined to generalize the analytical methodology being developed for the coal-related materials, including shale oil and diesel exhaust particulates. 35 references, 50 figures, 3 tables.

  8. Nanodomain structures with hierarchical inhomogeneities in PMN-PT.

    Science.gov (United States)

    Kurushima, Kosuke; Kobayashi, Keisuke; Mori, Shigeo

    2012-09-01

    The nanometric domain configuration of (1 - x) Pb(Mg(1/3)Nb(2/3))O(3-x)PbTiO(3) [(1 - x)PMN-xPT] single crystals in the monoclinic phase around a morphotropic phase boundary (MPB) has been examined thoroughly by means of transmission electron microscopy (TEM). Domain structures with hierarchically inhomogeneous configuration were found in the monoclinic phase near the MPB region around x ~ 0.32, which are characterized as nanoscaled lamella-type domain structures with ~10 nm width inside macroscopic-sized banded domains with 100 to 200 nm width. To elucidate formation processes of the domain structures with hierarchically inhomogeneous configuration, an in situ TEM observation of changes of the domain structures in the temperature window between 298K and 500K was carried out. It is revealed that these nanoscaled lamella-type domain structures with ~10 nm width appear inside the banded domains as a result of the tetragonal structure and are inherent to the monoclinic phase.

  9. Voyager Approaches Final Frontier

    Science.gov (United States)

    2003-01-01

    An artist's concept illustrates the positions of the Voyager spacecraft in relation to structures formed around our Sun by the solar wind. Also illustrated is the termination shock, a violent region the spacecraft must pass through before reaching the outer limits of the solar system. At the termination shock, the supersonic solar wind abruptly slows from an average speed of 400 kilometers per second to less than 100 kilometer per second (900,000 to less than 225,000 miles per hour). Beyond the termination shock is the solar system's final frontier, the heliosheath, a vast region where the turbulent and hot solar wind is compressed as it presses outward against the interstellar wind that is beyond the heliopause. A bow shock likely forms as the interstellar wind approaches and is deflected around the heliosphere, forcing it into a teardrop-shaped structure with a long, comet-like tail.The exact location of the termination shock is unknown, and it originally was thought to be closer to the Sun than Voyager 1 currently is. As Voyager 1 cruised ever farther from the Sun, it confirmed that all the planets are inside an immense bubble blown by the solar wind and the termination shock was much more distant.

  10. JAERI's contribution to the IAEA coordinated research programme on assuring structural integrity of reactor pressure vessels' (CRP-IV). Final report (Contract research)

    Energy Technology Data Exchange (ETDEWEB)

    Onizawa, Kunio; Suzuki, Masahide [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2000-05-01

    According to the Research Agreement No. 9736 between the IAEA and the JAERI, we commenced the test program for the IAEA Coordinated Research Program (CRP) on 'Assuring Structural Integrity of Reactor Pressure Vessels' at JAERI in September 1997. For the program, we received one block of the IAEA reference material JRQ from the IAEA CRP coordinator in June 1997. The test program has been conducted using the JRQ block and additional materials (Steels A and B) from our own program having a similar object with the CRP. The CRP consists of two parts; a mandatory part and an optional part. For the mandatory part of the JAERI program, instrumented Charpy impact tests and fracture toughness tests using precracked Charpy-v (PCCv) specimens were performed. As the optional part, neutron irradiation to specimens of JRQ was conducted at JMTR by using two capsules. In this report, the results of the mandatory part and irradiated Charpy and PCCv specimens of JRQ from capsule No.1 as well as those of Steel A and Steel B were described. The following conclusions were drawn; (1) the data form Charpy impact and fracture toughness tests of JRQ agreed well with the data in the CRP-3, (2) the scatter of fracture toughness of JRQ is relatively large, i. e., the Weibull slope 'b' is less than 3, (3) the reference temperature T{sub 0} from PCCv is in good agreement with T{sub 0} from 1T-Compact Tension (CT) when the tests are performed at the recommended temperature or the data has no invalid data, (4) the reference temperature T{sub 0} after neutron irradiation can be determined with six to eight specimens at the recommended temperature and (5) the shift of the reference temperature T{sub 0} is almost equivalent to the shift of Charpy transition temperature, but affected by the treatment of the highest data and testing temperature. Further studies on the fracture toughness evaluation are necessary concerning the treatment of outlier, temperature dependence after

  11. Growth, crystal structure and thermal properties of calcium bis(malate) dihydrate

    Energy Technology Data Exchange (ETDEWEB)

    Jini, T. [Department of Physics, St. Berchmans College, Changanassery 686 101, Kerala (India); Saban, K.V. [Department of Physics, St. Berchmans College, Changanassery 686 101, Kerala (India); Varghese, G. [Department of Physics, St. Berchmans College, Changanassery 686 101, Kerala (India); Naveen, S. [Department of Studies in Physics, University of Mysore, Mysore 570 006 (India); Sridhar, M.A. [Department of Studies in Physics, University of Mysore, Mysore 570 006 (India)]. E-mail: mas@physics.uni-mysore.ac.in; Prasad, J.S. [Department of Studies in Physics, University of Mysore, Mysore 570 006 (India)

    2007-05-16

    A new coordination compound crystal of calcium with malic acid is prepared by gel aided solution growth. Single crystal X-ray diffraction studies revealed that the structural formula of the compound is Ca(C{sub 4}H{sub 4}O{sub 5}){sub 2}.2H{sub 2}O. It crystallizes in the monoclinic system with space group C2/c, Z = 4, with unit cell parameters a = 15.916(9) A, b = 5.886(3) A, c = 13.046(6) A and {beta} = 90.678(4){sup o}. Data were collected by oscillation method and full-matrix least squares refinement was applied to the model converging to final R indices R {sub 1} = 0.0416 and {omega}R {sub 2} = 0.1255. Compound forms a layer-type polymeric structure, stabilized by intermolecular hydrogen bonding. Ca{sup 2+} is eight-fold coordinated. Malate is coordinated to Ca{sup 2+} tridendate-bidendate through two carboxylates and monodendate through oxygen atom of the hydroxyl group. Thermal behavior investigated using TG and DTA studies is in conformity with the proposed structure.

  12. Characterization and Crystal Structures of Two Copper(Ⅱ) Complexes Constructed by a Flexible Double Betaine Ligand

    Institute of Scientific and Technical Information of China (English)

    JIANG Ning-Yi; LI Song-Lin

    2007-01-01

    A flexible double betaine 1,4-bis(pyridinil-4-carboxylato)-1,4-dimethylbenzene L has been used to generate two Cu(Ⅱ)-containing metal complexes that exhibit different polymeric structures: [Cu(H2O)2 L]·2NO3 1 and [Cu(H2O)3 L]·2Cl·H2O 2. The crystal structures of 1 and 2have been determined by single-crystal X-ray diffraction method. Crystal data for 1: triclinic, space group P1-, a = 5.253(2), b = 7.406(3), c = 14.792(5) (A), α = 84.195(5), β = 80.014(5), γ =78.053(5)°, V = 553.2(3) (A)3, Z = 1, F(000) = 293, Dc = 1.717 g/cm3, the final R = 0.0385 and wR =0.1079 for 1883 observed reflections (I> 2σ(Ⅰ)); and those for 2: monoclinic, space group P21/c, a =10.222(3), b = 25.287(7), c = 9.277(3) (A),β = 93.572(5)°, V = 2393.2(12) (A)3, Z = 4, F(000) = 1140,Dc = 1.540 g/cm3, the final R = 0.0472 and wR = 0.0956 for 3204 observed reflections (I >2σ(Ⅰ)).

  13. 氮化锗多形体的四方、 单斜和正交畸变的理论研究%Theoretical Studies on Tetragonal, Monoclinic and Orthorhombic Distortions of Germanium Nitride Polymorphs

    Institute of Scientific and Technical Information of China (English)

    仓玉萍; 陈东; 杨帆; 杨慧明

    2016-01-01

    采用量子化学从头算方法,对Ge3 N4的四方、单斜和正交结构同质异相体的微结构、态密度和声子谱进行了研究.形成焓为负值、弹性常数满足Born稳定性准则和声子谱无虚频等结果证实在0~20 GPa范围内3种相都能保持结构稳定.温度变化影响到晶胞体积,从而使体模量发生改变.3种Ge3 N4都属于半导体,Ge原子和N原子之间存在明显的s-p杂化现象.当压强增大时诱发了离域电子,从而使体系的带隙减小.本文还采用准谐近似对Ge3 N4的热力学性质进行了研究,结果表明,温度和压强对热膨胀系数、 熵、 热容、德拜温度和格林爱森参数产生了明显影响.m-Ge3 N4和t-Ge3 N4的热膨胀系数分别为o-Ge3 N4的3倍和2倍.t-Ge3 N4和o-Ge3 N4的晶格谐振频率基本不受温度的影响.%Applying the ab initio pseudo-potential technique, we had predicted the lattice structures, density of states, phonon dispersion curves of the recently-discovered tetragonal, monoclinic and orthorhombic phases of Ge3 N4. The negative formation enthalpy, the satisfactory of Born ' s stability criteria and no imaginary frequency can be seen in the phonon dispersion curves proof that the three Ge3 N4 polymorphs can retain their stabilities in the pressure range of 0―20 GPa. The temperature affects the cell volume, thereby decreasing the bulk modulus. The band gaps show that Ge3 N4 are semiconductors, while obvious s-p hybridizations can be seen in the density of states. The band gaps decrease with applied pressure, which is due mainly to the generation of non-local electrons. Then, the quasi-harmonic approximation is used to study the thermodynamic properties of Ge3 N4. The results show that the thermal expansion coefficient, entropy, heat capacity, Debye temperature and Grüneisen parameter are significantly affected by both temperature and pressure. The thermal expansions of m-Ge3 N4 and t-Ge3 N4 are three and two times greater than that of

  14. Syntheses and Crystal Structures of Two New Compounds Containing Triarylamineand Benzoic Hydrazide Units [Zn(μ-O2CCH=CHCO2)(C3H4N2)(H2O)]n

    Institute of Scientific and Technical Information of China (English)

    邹武新; 于海涛; 郭辉; 孟继本

    2004-01-01

    Two new compounds containing triarylamine and benzoic hydrazide units, 4-[N,N-di(4-toyl)amino]benzaldehyde-N-(4-ethoxylphenyl)-formyl hydrazone 3a and 4-[N,N-di(4-toyl) amino]benzaldehyde-N-(2-ethoxylphenyl)-formyl hydrazone 3b, have been synthesized and their crystal structures (C30H29N3O2, Mr = 463.56) were interpreted by a combination technique of 1HNMR, IR, elemental analysis, mass spectra, UV-Vis spectra and X-ray crystallography, respec- tively. The crystal of 3a belongs to monoclinic, space group P21/n with a = 9.321(3) A, b = 11.046(4) A, c = 24.335(9) A, β=92.649(7)°, V = 2502.7(16) A3, Z = 4,μ =0.078 mm-1, Dc =1.230 g/cm3, F(000) = 984, the final R = 0.0590 and wR = 0.1316 for 4367observed reflections with I > 2σ(I). The crystal of 3b belongs to monoclinic, space group P21/c with a = 10.637(4) A, b = 24.138(10) A, c = 10.398(4) A, β= 104.913(8)°, V= 2579.8(17) A3, Z = 4,μ = 0.075 mm-1, Dc = 1.194 g/cm3, F(000) = 984, the final R =0.0631 and wR =0.1006 for 4463 observed reflections with I > 2σ(I). X-ray crystallography revealed that the nitrogen atom in the triarylamine moiety is of sp2 hybridization with the three phenyl rings twisted to each other.

  15. 不规则单斜地层中磁弹性剪切波的色散方程%Dispersion Equation of Magnetoelastic Shear Waves in an Irregular Monoclinic Layer

    Institute of Scientific and Technical Information of China (English)

    A·查托帕答雅; S·古普塔; S·A·萨胡; A·K·辛格; 黄雅意

    2011-01-01

    The propagation of horizontally polarised shear waves in an internal magnetoelastic monoclinic stratum with irregularity in lower interface was studied. The stratum was sandwiched between two magnetoelastic monoclinic semi-infinite media. Dispersion equation was obtained in closed form. In absence of magnetic field and irregularity of the medium, the dispersion equation agrees with the equation of classical case in three layered media. The effect of magnetic field and size of irregularity on the phase velocity has been depicted by means of graphs.%在内夹磁弹性单斜地层中,下界面不规则变化时,研究水平偏振剪切波的传播,该地层夹在两个半无限磁弹性单斜介质之间,得到了闭式的色散方程.不计磁场及介质界面的不规则性,该色散方程与三层介质中经典方程相一致.图示了磁场和界面不规则深度对相速度的影响.

  16. One and Two-dimensional Structures of a New Oxamido Copper(Ⅱ) Complex with Phthalato Bridged

    Institute of Scientific and Technical Information of China (English)

    CHEN Jing; JIANG Zong-Hui; LIAO Dai-Zheng; YAN Shi-Ping

    2005-01-01

    A new o-phthalato-bridged oxamide copper(Ⅱ) complex 1, {[Cu2(oxap)](pht)4H2O}n (oxap = N, N'-bis(2-aminopropyl)oxamide, pht = phthalate dianion), has been prepared and structurally characterized. It crystallizes in monoclinic, space group C2/c with a = 23.424(4), b = 7.9696(14), c = 15.727(3) (A), β = 129.617(2)°, C16H28Cu2N4O10, Mr = 563.50, V = 2261.6(7) (A)3, Z = 4, Dc = 1.655 g/cm3,μ(MoKα) = 1.939 mm 1, F(000) = 1160, the final R = 0.0393 and wR = 0.0928 for 1707 observed reflections with I > 2σ(Ⅰ). Single-crystal X-ray analysis reveals that 1 displays a one-dimensional zigzag chain structure, in which each Cu(oxap) moiety adopting trans-conformation is connected by μ1,6-phthalate anion bridges, and these zigzag chains are further linked by anotherμ1,6-phthalate anion bridge to form a 2D sheet structure. The polar guest water molecules reside in the inter- and intrasheets to stabilize the whole crystal structure.

  17. Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Schuur, Edward [Northern Arizona Univ., Flagstaff, AZ (United States); Luo, Yiqi [Univ. of Oklahoma, Norman, OK (United States)

    2016-12-01

    This final grant report is a continuation of the final grant report submitted for DE-SC0006982 as the Principle Investigator (Schuur) relocated from the University of Florida to Northern Arizona University. This report summarizes the original project goals, as well as includes new project activities that were completed in the final period of the project.

  18. Final Focus Test Stand final report

    CERN Document Server

    Jeremie, A; Burrows, P

    2013-01-01

    Future Linear colliders will need particle beam sizes in the nanometre range. The beam also needs to be stable all along the beam line and especially at the Final Focus section. A dedicated Final Focus test stand has been used for this study and is comprised of several sub-parts. First there is the Stabilisation/Isolation system with sensors and actuators stabilizing down to sub-nanometre level. Then the Magnet itself needs to comply with very specific design constraints. In addition to the mechanical items, the beam can be stabilized acting on the trajectory directly and Beam-based controls have been developed and tested on different accelerator facilities.

  19. Structural, electronic, and hyperfine properties of pure and Ta-doped m-ZrO2

    DEFF Research Database (Denmark)

    Taylor, M.A.; Alonso, R.E.; Errico, L.A.

    2012-01-01

    A combination of experiments and ab initio quantum-mechanical calculations has been applied to examine electronic, structural, and hyperfine interactions in pure and Ta-doped zirconium dioxide in its monoclinic phase (m-ZrO2). From the theoretical point of view, the full-potential linear augmented...

  20. Influence of crystal structure of nanosized ZrO2 on photocatalytic degradation of methyl orange

    Science.gov (United States)

    Basahel, Sulaiman N.; Ali, Tarek T.; Mokhtar, Mohamed; Narasimharao, Katabathini

    2015-02-01

    Nanosized ZrO2 powders with near pure monoclinic, tetragonal, and cubic structures synthesized by various methods were used as catalysts for photocatalytic degradation of methyl orange. The structural and textural properties of the samples were analyzed by X-ray diffraction, Raman spectroscopy, TEM, UV-vis, X-ray photoelectron spectroscopy (XPS), and N2 adsorption measurements. The performance of synthesized ZrO2 nanoparticles in the photocatalytic degradation of methyl orange under UV light irradiation was evaluated. The photocatalytic activity of the pure monoclinic ZrO2 sample is higher than that of the tetragonal and cubic ZrO2 samples under optimum identical conditions. The characterization results revealed that monoclinic ZrO2 nanoparticles possessed high crystallinity and mesopores with diameter of 100 Å. The higher activity of the monoclinic ZrO2 sample for the photocatalytic degradation of methyl orange can be attributed to the combining effects of factors including the presence of small amount of oxygen-deficient zirconium oxide phase, high crystallinity, large pores, and high density of surface hydroxyl groups.

  1. Influence of crystal structure of nanosized ZrO2 on photocatalytic degradation of methyl orange.

    Science.gov (United States)

    Basahel, Sulaiman N; Ali, Tarek T; Mokhtar, Mohamed; Narasimharao, Katabathini

    2015-01-01

    Nanosized ZrO2 powders with near pure monoclinic, tetragonal, and cubic structures synthesized by various methods were used as catalysts for photocatalytic degradation of methyl orange. The structural and textural properties of the samples were analyzed by X-ray diffraction, Raman spectroscopy, TEM, UV-vis, X-ray photoelectron spectroscopy (XPS), and N2 adsorption measurements. The performance of synthesized ZrO2 nanoparticles in the photocatalytic degradation of methyl orange under UV light irradiation was evaluated. The photocatalytic activity of the pure monoclinic ZrO2 sample is higher than that of the tetragonal and cubic ZrO2 samples under optimum identical conditions. The characterization results revealed that monoclinic ZrO2 nanoparticles possessed high crystallinity and mesopores with diameter of 100 Å. The higher activity of the monoclinic ZrO2 sample for the photocatalytic degradation of methyl orange can be attributed to the combining effects of factors including the presence of small amount of oxygen-deficient zirconium oxide phase, high crystallinity, large pores, and high density of surface hydroxyl groups.

  2. Advancement and testing of analysis techniques for the determination of the structural dynamic behavior of containment structures. Final report; Weiterentwicklung und Erprobung von Analysemethoden zur Bestimmung des strukturdynamischen Verhaltens von Containmentstukturen. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Sievers, Juergen; Bahr, Ludwig; Arndt, Jens; Heckoetter, Christian; Grebner, Hans

    2014-11-15

    Within the framework of project RS1197, analysis methods have been further developed and tested for the determination of the structural dynamic loading and the maximum load-bearing capacity of containment structures with a focus on the quantification of safety margins against failures due to loads resulting from selected internal and external hazards. The analyses comprised a model containment structure of prestressed reinforced concrete under internal pressure loading until reaching failure pressure, an outer containment structure made of reinforced concrete under local impact loads that may occur during a targeted aircraft crash, and a steel containment under local peak loads from internal pressure and temperature loads due to core melt scenarios with a local hydrogen combustion. GRS participated in the international ''Standard Problem Exercise 3'' on the issue ''Performance of Containment Vessel under Severe Accident Conditions''. Together with the cooperation partners, aspects of the global containment behaviour were considered based on the example of the Sandia 1:4 model containment of prestressed concrete, which was loaded by rising internal pressure until failure. Complex analysis models were developed, calculating the behaviour of the prestressing tendons under consideration of the frictional contact with the cladding tubes. Compared with corresponding measurement values, the analysis results show that the stresses near the tensioning device and the deformation of the inner surface can be realistically modelled as a function of the internal pressure. In the experiment, global structural failure of the containment model was caused by tendon rupture at about 3.64 times the design pressure. With the developed analysis models of a generic structure of an outer reinforced concrete containment, simulations were carried out for various aircraft crash scenarios as contact problems with explicit impactor simulation. For this

  3. CARBOXYLATE SUBSTITUTION PATTERN AS STRUCTURAL DIRECTIVE FOR THE FINAL PRODUCTS: SYNTHESIS, STRUCTURE AND PROPERTIES OF [Fe4Ca2O2(μ2-HCCl2COO10(μ3-HCCl2COO2(THF6

    Directory of Open Access Journals (Sweden)

    Denis Prodius

    2008-12-01

    Full Text Available A novel hexanuclear iron-calcium-oxo complex has been synthesized and characterized by different physico-chemical methods and X-ray single crystal structural analysis: [Fe4Ca2O2(μ2-HCCl2COO10(μ3-HCCl2COO2(THF6].The molecular structure shows that there are two types of coordination for COO- anions: bidentate and tridentate.The corresponding variable temperature susceptibility measurement shows that in the complex there exists an antiferromagnetic interaction (|J12| = |J34| = -71.86 cm-1. The iron(III high spin state (5/2 is proved by Mössbauer spectroscopy. High magnetic EPR measurements of 1 indicates the presence of S=0 ground state with low-lying S=1 excited state centred around g = 2.0054 ±0.0001.

  4. Omega, the final multiplier

    Science.gov (United States)

    Buckley, T. N.

    2008-12-01

    The application of optimisation theory to vegetation processes has rarely extended beyond the context of diurnal to intra-annual gas exchange of individual leaves and crowns. One reason is that the Lagrange multipliers in the leaf-scale solutions, which are marginal products for allocatable photosynthetic resource inputs (water and nitrogen), are mysterious in origin, and their numerical values are difficult to measure -- let alone to predict or interpret in concrete physiological or ecological terms. These difficulties disappear, however, when the optimisation paradigm itself is extended to encompass carbon allocation and growth at the lifespan scale. The trajectories of leaf (and canopy) level marginal products are then implicit in the trajectory of plant and stand structure predicted by optimal carbon allocation. Furthermore, because the input and product are the same resource -- carbon -- in the whole plant optimisation, the product in one time step defines the input constraint, and hence implicitly the marginal product for carbon, in the next time step. This effectively converts the problem from a constrained optimisation of a definite integral, in which the multipliers are undetermined, to an unconstrained maximisation of a state, in which the multipliers are all implicit. This talk will explore how the marginal products for photosynthetic inputs as well as the marginal product for carbon -- i.e., the 'final multiplier,' omega -- are predicted to vary over time and in relation to environmental change during tree growth.

  5. Pressure induced structural phase transition in SnS—An ab initio study

    Indian Academy of Sciences (India)

    M Rajagopalan; G Kalpana; V Priyamvadha

    2006-02-01

    The structural behaviour of SnS under pressure has been investigated by first principle density functional calculations of the total energy by the TB–LMTO approach. We find that SnS undergoes a structural phase transition from orthorhombic type to monoclinic type structure around 17 GPa which is in good agreement with the recent experimental study. In addition, the ground state properties are computed and compared with the available results.

  6. Coal surface structure and thermodynamics. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, J.W.; Wernett, P.C.; Glass, A.S.; Quay, D.; Roberts, J.

    1994-05-01

    Coals surfaces were studied using static surface adsorption measurements, low angle x-ray scattering (LAXS), inverse gas chromatography (IGC) and a new {sup 13}C NMR relaxation technique. A comparison of surface areas determined by hydrocarbon gas adsorption and LAXS led to the twin conclusions that the hydrocarbons had to diffuse through the solid to reach isolated pores and that the coal pores do not form interconnected networks, but are largely isolated. This conclusion was confirmed when IGC data for small hydrocarbons showed no discontinuities in their size dependence as usually observed with porous solids. IGC is capable of providing adsorption thermodynamics of gases on coal surfaces. The interactions of non-polar molecules and coal surfaces are directly proportioned to the gas molecular polarizability. For bases, the adsorption enthalpy is equal to the polarizability interaction plus the heat of hydrogen bond formation with phenol. Amphoteric molecules have more complex interactions. Mineral matter can have highly specific effects on surface interactions, but with most of the molecules studied is not an important factor.

  7. Presence of a monoclinic (Pm) phase in the morphotropic phase boundary region of multiferroic (1 − x)Bi(Ni{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} solid solution: A Rietveld study

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Rishikesh, E-mail: akhilesh-bhu@yahoo.com, E-mail: aksingh.mst@itbhu.ac.in; Singh, Akhilesh Kumar, E-mail: akhilesh-bhu@yahoo.com, E-mail: aksingh.mst@itbhu.ac.in [School of Materials Science and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India)

    2014-07-28

    We present here the results of structural studies on multiferroic (1 − x)Bi(Ni{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} solid solution using Rietveld analysis on powder x-ray diffraction data in the composition range 0.35 ≤ x ≤ 0.55. The stability region of various crystallographic phases at room temperature for (1 − x)Bi(Ni{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} is determined precisely. Structural transformation from pseudo-cubic (x ≤ 0.40) to tetragonal (x ≥ 0.50) phase is observed via phase coexistence region demarcating the morphotropic phase boundary. The morphotropic phase boundary region consists of coexisting tetragonal and monoclinic structures with space group P4mm and Pm, respectively, stable in composition range 0.41 ≤ x ≤ 0.49 as confirmed by Rietveld analysis. The results of Rietveld analysis completely rule out the coexistence of rhombohedral and tetragonal phases in the morphotropic phase boundary region reported by earlier workers. A comparison between the bond lengths for “B-site cations-oxygen anions” obtained after Rietveld refinement, with the bond length calculated using Shannon-Prewitt ionic radii, reveals the ionic nature of B-O (Ni/Ti-O) bonds for the cubic phase and partial covalent character for the other crystallographic phases.

  8. Effects of low-temperature catalytic pretreatments on coal structure and reactivity in liquefaction. Final technical report, Volume 1 - effects of solvents, catalysts and temperature conditions on conversion and structural changes of low-rank coals

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Lili [Pennsylvania State Univ., University Park, PA (United States); Schobert, Harold H. [Pennsylvania State Univ., University Park, PA (United States); Song, Chunshan [Pennsylvania State Univ., University Park, PA (United States)

    1998-01-01

    The main objectives of this project were to study the effects of low-temperature pretreatments on coal structure and their impacts on subsequent liquefaction. The effects of pretreatment temperatures, catalyst type, coal rank, and influence of solvent were examined. Specific objectives were to identify the basic changes in coal structure induced by catalytic and thermal pretreatments, and to determine the reactivity of the catalytically and thermally treated coals for liquefaction. In the original project management plan it was indicated that six coals would be used for the study. These were to include two each of bituminous, subbituminous, and lignite rank. For convenience in executing the experimental work, two parallel efforts were conducted. The first involved the two lignites and one subbituminous coal; and the second, the two bituminous coals and the remaining subbituminous coal. This Volume presents the results of the first portion of the work, studies on two lignites and one subbituminous coal. The remaining work accomplished under this project will be described and discussed in Volume 2 of this report. The objective of this portion of the project was to determine and compare the effects of solvents, catalysts and reaction conditions on coal liquefaction. Specifically, the improvements of reaction conversion, product distribution, as well as the structural changes in the coals and coal-derived products were examined. This study targeted at promoting hydrogenation of the coal-derived radicals, generated during thermal cleavage of chemical bonds, by using a good hydrogen donor-solvent and an effective catalyst. Attempts were also made in efforts to match the formation and hydrogenation of the free radicals and thus to prevent retrogressive reaction.

  9. Further development of the structure mechanics analysis method for the calculation of the structure reliability of passive components, phase II. Final report; Weiterentwicklung der strukturmechanischen Analysemethodik zur Bestimmung der Strukturzuverlaessigkeit passiver Komponenten, Phase II. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Grebner, H.; Wang, Y.; Schmipfke, T.; Sievers, J.

    2010-06-15

    Within the framework of research project RS 1163 the computer code PROST for the quantitative assessment of the structural reliability of pipe components has been further developed. Thereby models were provided and tested for the consideration of the damage mechanism 'corrosion' to determine leak and break probabilities in cylindrical structures of ferritic and austenitic reactor steels. These models are now additionally available to the model for the consideration of the damage mechanism 'fatigue'. Furthermore, the application range of the code was extended to complex geometries in regards to loading and boundary conditions. Additional code modules were developed to be able to include the results of finite element (FE) calculations. The extended analysis method was tested, amongst others, in the context of calculations for a cracked feedwater nozzle of a steam generator under thermal-mechanical cyclic loading. The stress on cracks was calculated with the FE-method. For the determination of leak probabilities the crack growth due to fatigue was estimated taking into account the ''mixed-mode'' - loading within the J-integral vector approach. Altogether, the analyses show that with the provided flexible probabilistic analysis method quantitative determination of leak probabilities of a detected or postulated crack in a complex structure geometry under thermal-mechanical loading as function of the operating time in the range of very small probability values (<1.0 E-8) to large values (>1.0 E-2) are possible. The next development steps should comprise especially the improvement of the accuracy of the method to determine break probabilities and also the consideration of approaches on crack formation due to the damage mechanisms 'fatigue' and 'corrosion', based on evaluations of national and international operating experiences.

  10. Hydrothermal Synthesis, Crystal Structure and Electrochemical Behavior of 2d Hybrid Coordination Polymer

    Science.gov (United States)

    Fan, Weiqiang; Zhu, Lin; Shi, Weidong; Chen, Fuxiao; Bai, Hongye; Song, Shuyan; Yan, Yongsheng

    2013-06-01

    A novel metal-organic coordination polymer [Cu(phen)(L)0.5(H2O)]n (H4L = (N,N‧-5,5‧-bis(isophthalic acid)-p-xylylenediamine, and phen = 1,10-phenanthroline) has been hydrothermally synthesized and characterized by elemental analysis, IR, TGA, and single-crystal X-ray diffraction. The crystallographic data show that the title compound crystallizes in monoclinic space group P21/n with a = 10.682(2), b = 15.682(3), c = 11.909(2) Å, β = 91.39(3)°, V = 1994.3(7) Å3, C24H17CuN3O5, Mr = 490.95, Dc = 1.635 g/cm3, F(000) = 1004, Z = 4, μ(MoKα) = 1.141 mm-1, the final R = 0.0418 and wR = 0.0983 for 3578 observed reflections (I > 2σ(I)). The structural analyses reveal that the title compound exhibits shows a 2D layer structure, which are further linked by hydrogen bonding interactions to form a three-dimensional supramolecular network. In addition, the thermal stability and electrochemical behavior of title compound has been studied. CCDC: 900413.

  11. Synthesis and Crystal Structure of a New Cadmium(Ⅱ) Coordination Polymer with Ethylenediaminetetraacetic Acid

    Institute of Scientific and Technical Information of China (English)

    ZHENG Jian-Mei; WU Mei-Feng; ZHENG Fa-Kun; LIU Hua

    2012-01-01

    A new cadmium(Ⅱ) coordination polymer,namely,[KCd2(edta)I]n(1,H4edta = ethylenediaminetetraacetic acid),has been prepared and structurally characterized by single-crystal X-ray diffraction.Crystallographic data for 1:C10H12Cd2IKN2O8,Mr = 679.02,monoclinic,space group P21/n,a = 9.870(5),b = 8.989(4),c = 19.082(10) ,β = 104.581(10)o,V = 1638.5(13) 3,Z = 4,Dc = 2.753 g/cm3,μ = 4.776 mm-1,F(000) = 1272,the final R = 0.0473 and wR = 0.1311 for 2846 observed reflections with I 〉 2σ(I).Polymer 1 features a 2-D layered structure,in which each edta4-ligand chelates/bridges five adjacent six-/seven-coordinated Cd(Ⅱ) centers with all ten donors(eight oxygen and two nitrogen) involved with coordination.Additional iodide I-ions as counterions are bound to the Cd(Ⅱ) centers in a terminal mode and the potassium K+ ions are located in the layers and surrounded by O and I atoms from neighboring environment.The thermal stability of 1 has been discussed.

  12. Structure and Luminescence Property of a Hexanuclear Silver(I) Cluster Containing Pyridine-3-carboxaldehyde Thiosemicarbazone

    Institute of Scientific and Technical Information of China (English)

    SUN Qiao-Zhen; CHAI Li-Yuan

    2012-01-01

    A new hexanuclear silver(I) compound containing thiosemicarbazone with group of 3-pyridine was synthesized and structurally characterized by single-crystal X-ray diffraction,elemental analysis and fluorescence spectrum.The title compound 3 crystallizes in monoclinic,space group C2/m with a = 18.6523(9),b = 24.7519(11),c = 22.4542(15) ,β = 93.4960(10)°,V = 10347.4(10)3,C68H104Ag6N30O8S6,Mr = 2309.39,Dc = 1.482g/cm3,μ(MoKα) = 1.293 mm-1,F(000) = 4656,Z = 4,the final R = 0.0544 and wR = 0.1580 for 6733 observed reflections(I 〉 2σ(I)).In the structure,two Ag6L36(L3 = pyridine-3-carboxaldehyde thiosemicarbazone) clusters are contained.In each cluster,the S atom of ligand L3 served as a triply bridged chelator to connect the six silver atoms into a Ag6L36 cluster.Luminescence investigation revealed that the band at 630 nm was attributed to cluster-centered(CC) electron transfer,and those at 493 and 530 nm to the LMCT and CC transitions,respectively.

  13. Crystal Structure, Photoluminescent, and Theoretical Studies of 3-Acetyl-8-methoxy-coumarin

    Institute of Scientific and Technical Information of China (English)

    LI Jing; LI Xiang-Gao; WANG Shi-Rong

    2012-01-01

    The structure of 3-acetyl-8-methoxy-coumarin (AMC) was verified by single-crystal X-ray crystallography. It crystallizes in monoclinic, space group C2/c with a=15.073(3), b=13.068(3), c=11.549(2), β=119.92(3)o, V=1971.7(7)3 , Z=8, F(000)=912, D c=1.470 Mg/m3 , Mr=218.20, μ=0.111 mm-1 , the final R=0.0340 and wR=0.0968 for 1446 observed reflections with I 〉 2σ(I). The UV-vis absorption and fluorescence of AMC were discussed. The compound exhibits strong blue emission under ultraviolet light excitation. The molecular structure of AMC was optimized using density functional theory (DFT) at the B3LYP/6-31G(d) level, showing that the optimized geometer parameters are in good agreement with the experiment data. In addition, the HOMO and LUMO levels of AMC were deduced.

  14. Synthesis and Crystal Structure of Tetraaquacopper(II) Bis(5-fluorouracil-1-acetate) Tetrahydrate

    Institute of Scientific and Technical Information of China (English)

    WANG Wei-Dong; HU Mao-Lin

    2006-01-01

    The title compound, [Cu(C6H4N2O4F)2(H2O)4]·4(H2O) I, has been hydrothermally synthesized and structurally determined by single-crystal X-ray diffraction method. It crystallizes in monoclinic, space group P21/c with a = 8.3041(17), b = 12.045(2), c = 11.077(2) (A), β = 92.567(3)o, V = 1106.8(4)(A)3, Mr = 581.89, Z = 2, Dc = 1.746 g/cm3, F(000) = 598, μ(MoKα) = 1.090 mm-1, the final R = 0.0296 and wR = 0.0806 for 3195 observed reflections with I > 2σ(I). In the centrosymme- tric compound I, each Cu(II) ion is coordinated by six O atoms from two 5-fluorouracil-1-acetate anions and four water molecules, forming a six-coordinated octahedral environment. N-H…O and O-H…O hydrogen-bonding interactions are observed in the structure, leading to the formation of a three-dimensional network.

  15. Domain structure and magnetic resonance studies of ferroelastic BiVO4 revisited

    Science.gov (United States)

    Choh, Sung Ho; Jang, Min Su

    2016-04-01

    Bismuth vanadate (BiVO4) is a ferroelastic material undergoing a reversible second order phase transition at 528 K(T c) between the tetragonal and monoclinic structure. There have been experimental studies on the incommensurate domain wall (W‧) which reported different orientation angles. In order to clarify this we have tried to calculate it numerically in terms of lattice constants above and below T c by employing the theory of Sapriel, and obtained it to be either 35.9° or 54.1°. It also turns out that the shear strain (S 21) in the ferroelastic phase depends on the crystal growing condition. The remaining internal stress appears to be responsible for the formation of W‧ wall. The host atom nuclear magnetic resonance and the S-state impurity electron magnetic resonance are also reviewed. The nuclear electric quadrupole interaction of 51V and 209Bi in BiVO4 was evaluated in terms of the point charge model based on the crystal structure. The result of electric field gradient tensor turns out to be reasonable with experimental values. The zero-field splitting tensor of Mn2+, Fe3+ and Gd3+ are also compared, and the deduced local environment of these ions in the host are confirmed. Finally the second-order phase transition according to the Landau’s framework is found in this crystal from the temperature dependence of magnetic resonance parameters. Supported by The National Academy of Sciences, Republic of Korea (2014) through SHC.

  16. Synthesis, Structure and Biological Activities of Novel Triazole Compounds Containing Thioamide Group

    Institute of Scientific and Technical Information of China (English)

    刘法谦; 秦永其; 许良忠; 陆路德; 杨绪杰; 汪信

    2005-01-01

    Two compounds 2-benzoyl-N-phenyl-2-( 1,2,4-triazol- 1-yl)thioacetamide (1) and 2-(4-chlorobenzoyl)-N-phenyl-2-(1,2,4-triazol-1-yl)thioacetamide (2) were synthesized from substituted acetophenone, triazole and phenyl isothiocyanate by several step reactions. The structure of compound 1 was determined by single-crystal X-ray diffraction analysis. It crystallizes in monoclinic system with space group P21/c, a =0.8806(2) nm, b= 1.2097(2) nm, c= 1.4809(3) nm, β=105.88°, Z=4, V=1.5173(6) nm3, Dc= 1.411 Mg/m3, μ=0.22 mm-1, F(000)=672, final R1=0.040 and Rw=0.103. There is obvious potentially weak C—H…N intermolecular interaction in the crystal, which stabilizes the structure. The results of biological test show that the two compounds have antifungal and plant growth regulating activities.

  17. The crystal structure and microtwinning of ferro-pedrizite, a new lithium amphibole

    Science.gov (United States)

    Aksenov, S. M.; Rastsvetaeva, R. K.; Konovalenko, S. I.; Ananyev, S. A.; Chukanov, N. V.; Miroshkina, A. E.

    2015-07-01

    The structure of ferro-pedrizite—a new lithium mineral of the amphibole supergroup—has been studied by single-crystal X-ray diffraction. Fe2+ ions dominate over Mg in the chemical composition of this mineral. The parameters of the monoclinic unit cell are a = 9.3716(4) Å, b = 17.649(1) Å, c = 5.2800(6) Å, and β = 102.22(1)°. The experimental set of intensities contains a large number of significant reflections (~10%), which violate the Clattice. Consideration of pseudomerohedral twinning (matrix [1 0 0/00/-3/4 0]) allowed us to solve and refine the structure within the sp. gr. C2/ m to the final value R = 3.9% in the anisotropic approximation of atomic displacements using 4843 I > 2σ( I). The twin components are found to be 0.681(3)/0.319(3). Twinning has been revealed for the first time in amphiboles of the pedrizite family. The idealized formula of ferro-pedrizite ( Z = 2) is determined as NaLi2(Al2Li)[Si8O22](OH)2.

  18. Structure of BaGd2(MoO4)4 Crystal

    Institute of Scientific and Technical Information of China (English)

    ZHAO Dan; LIN Zhou-Bin; WANG Guo-Fu

    2007-01-01

    The title compound belongs to monoclinic, space group C2/c with a = 5.2694(1),b = 12.6659(4), c = 19.4108(2) (A),β = 91.504(2)°, V = 1295.06(5) (A)3, Z = 4 and Dc= 5.599 g/cm3.The structure of BaGd2(MoO4)4 contains a MoO4 tetrahedron, a distorted GdO8 polyhedron, and Ba2+ ions in a tenfold coordination. The GdO8 polyhedra are linked together through edge-sharing to give a two-dimensional Gd layer. The MoO4 tetrahedra connected to the Gd atoms are capped up and down the Gd layer through common oxygen apices, thus forming a new Gd-Mo layer. Finally,the Gd-Mo layers are held together through bridging BaO10 polyhedra to form a three-dimensional framework. Since the Ba-μ3-O bond has a large average distance of 2.888 (A), this structural characteristic will result in a cleavage along the (001) plane.

  19. Synthesis, Crystal Structure, and Thermal Decomposition of the Cobalt(II Complex with 2-Picolinic Acid

    Directory of Open Access Journals (Sweden)

    Di Li

    2014-01-01

    Full Text Available The cobalt(II complex of 2-picolinic acid (Hpic, namely, [Co(pic2(H2O2]·2H2O, was synthesized with the reaction of cobalt acetate and 2-picolinic acid as the reactants by solid-solid reaction at room temperature. The composition and structure of the complex were characterized by elemental analysis, infrared spectroscopy, single crystal X-ray diffraction, and thermogravimetry-differential scanning calorimetry (TG-DSC. The crystal structure of the complex belongs to monoclinic system and space group P2(1/n, with cell parameters of a=9.8468(7 Å, b=5.2013(4 Å, c=14.6041(15 Å, β=111.745(6°, V=747.96(11 Å3, Z=2, Dc=1.666 g cm−3, R1=0.0297, and wR2=0.0831. In the title complex, the Co(II ion is six-coordinated by two pyridine N atoms and two carboxyl O atoms from two 2-picolinic acid anions, and two O atoms from two H2O molecules, and forming a slightly distorted octahedral geometry. The thermal decomposition processes of the complex under nitrogen include dehydration and pyrolysis of the ligand, and the final residue is cobalt oxalate at about 450°C.

  20. Effects of low-temperature catalytic pretreatments on coal structure and reactivity in liquefaction. Final technical report, Volume 2 - hydrogenative and hydrothermal pretreatments and spectroscopic characterization using pyrolysis-GC-MS, CPMAS {sup 13}C NMR and FT-IR

    Energy Technology Data Exchange (ETDEWEB)

    Chunshan Song; Hatcher, P.G.; Saini, A.K.; Wenzel, K.A.

    1998-01-01

    It has been indicated by DOE COLIRN panel that low-temperature catalytic pretreatment is a promising approach to the development of an improved liquefaction process. This work is a fundamental study on effects of pretreatments on coal structure and reactivity in liquefaction. The main objectives of this project are to study the coal structural changes induced by low-temperature catalytic and thermal pretreatments by using spectroscopic techniques; and to clarify the pretreatment-induced changes in reactivity or convertibility of coals. As the second volume of the final report, here we summarize our work on spectroscopic characterization of four raw coals including two subbituminous coals and two bituminous coals, tetrahydrofuran (THF)-extracted but unreacted coals, the coals (THF-insoluble parts) that have been thermally pretreated. in the absence of any solvents and in the presence of either a hydrogen-donor solvent or a non-donor solvent, and the coals (THF-insoluble parts) that have been catalytically pretreated in the presence of a dispersed Mo sulfide catalyst in the absence of any solvents and in the presence of either a hydrogen-donor solvent or a non-donor solvent.

  1. Materials for Adaptive Structural Acoustic Control. Volume 1

    Science.gov (United States)

    1993-04-06

    unusual response of thin film BaTiO3 is discussed in Appendix 49, which shows that for small grains (6-8 nm) the structure is cubic nonferroelectric, but...smart dental braces made from shape memory alloys Smart hulls and propulsion systems for navy ships and submarines that detect flow noise, remove... zirconia are a good example. Here the tetragonal-monoclinic phase change accompanied by ferroelastic twin wail motion are the stand-by phenomena capable of

  2. Synthesis, Structure and Biological Activities of Novel Triazole Compounds Containing 4,6-Dimethyl-pyrimidin-2-ylthio Group

    Institute of Scientific and Technical Information of China (English)

    XU, Liang-Zhong(许良忠); JIAN, Fang-Fang(建方方); SHI, Jian-Gang(时建刚); LI, Lin(李琳)

    2004-01-01

    Four compounds were prepared by reacting 4,6-dimethyl-2-mercaptopyrimidine with α-bromo-α-(1,2,4-triazol-1-yl)-substituted acetylbenzene. Their structures were identified by means of elemental analysis, IR, and 1H NMR spectra. The single crystal structure of 2- [ 1 -(1,2,4-triazol- 1-yl)- 1-p-methoxyphenylcarbonylmethylthio] -4,6-dimethyl-pyrimidine was also determined. It crystallizes in monoclinic system, space group P21/c, a=0.8016(2) nm, b=1.2462(3) nm, c= 1.7824(4) nm,β=99.89(3)°, Z=4, V=1.7540(7) nm3, Dc=1.346 g/cm3, μ=0.205 mm-1, F(000)=744, final R1=0.0452. There is obviously potentially weak C-H…N intermolecular interaction between the molecules in the crystal lattice, which stabilizes the crystal structure. The result of the biological test showed that the four compounds all have some fungicidal and plant growth regulating activities.

  3. Evidence for anisotropic dielectric properties of monoclinic hafnia using valence electron energy-loss spectroscopy in high-resolution transmission electron microscopy and ab initio time-dependent density-functional theory

    Energy Technology Data Exchange (ETDEWEB)

    Guedj, C. [University Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Hung, L.; Sottile, F. [LSI, CNRS, CEA, École Polytechnique, F-91128 Palaiseau (France); European Theoretical Spectroscopy Facility (ETSF) (France); Zobelli, A. [LPS, CNRS and University Paris Sud, F-91405 Orsay (France); Blaise, P. [University Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); European Theoretical Spectroscopy Facility (ETSF) (France); Olevano, V. [University Grenoble Alpes, F-38000 Grenoble (France); European Theoretical Spectroscopy Facility (ETSF) (France); CNRS, Institut Néel, F-38042 Grenoble (France)

    2014-12-01

    The effect of nanocrystal orientation on the energy loss spectra of monoclinic hafnia (m-HfO{sub 2}) is measured by high resolution transmission electron microscopy (HRTEM) and valence energy loss spectroscopy (VEELS) on high quality samples. For the same momentum-transfer directions, the dielectric properties are also calculated ab initio by time-dependent density-functional theory (TDDFT). Experiments and simulations evidence anisotropy in the dielectric properties of m-HfO{sub 2}, most notably with the direction-dependent oscillator strength of the main bulk plasmon. The anisotropic nature of m-HfO{sub 2} may contribute to the differences among VEELS spectra reported in literature. The good agreement between the complex dielectric permittivity extracted from VEELS with nanometer spatial resolution, TDDFT modeling, and past literature demonstrates that the present HRTEM-VEELS device-oriented methodology is a possible solution to the difficult nanocharacterization challenges given in the International Technology Roadmap for Semiconductors.

  4. Evidence for anisotropic dielectric properties of monoclinic hafnia using valence electron energy-loss spectroscopy in high-resolution transmission electron microscopy and ab initio time-dependent density-functional theory

    Science.gov (United States)

    Guedj, C.; Hung, L.; Zobelli, A.; Blaise, P.; Sottile, F.; Olevano, V.

    2014-12-01

    The effect of nanocrystal orientation on the energy loss spectra of monoclinic hafnia (m-HfO2) is measured by high resolution transmission electron microscopy (HRTEM) and valence energy loss spectroscopy (VEELS) on high quality samples. For the same momentum-transfer directions, the dielectric properties are also calculated ab initio by time-dependent density-functional theory (TDDFT). Experiments and simulations evidence anisotropy in the dielectric properties of m-HfO2, most notably with the direction-dependent oscillator strength of the main bulk plasmon. The anisotropic nature of m-HfO2 may contribute to the differences among VEELS spectra reported in literature. The good agreement between the complex dielectric permittivity extracted from VEELS with nanometer spatial resolution, TDDFT modeling, and past literature demonstrates that the present HRTEM-VEELS device-oriented methodology is a possible solution to the difficult nanocharacterization challenges given in the International Technology Roadmap for Semiconductors.

  5. Crystal structure of putrescine aspartic acid complex

    OpenAIRE

    Ramaswamy, S.; Murthy, MRN

    1990-01-01

    Polyamines, putrescine, spermidine and spermine are ubiquitous biogenic cations believed to be important for a variety of cellular processes. In order to obtain structural information on the interaction of these amines with other biomolecules, the structure of a complex of putrescine with aspartic acid was determined using single crystal X-ray diffraction methods. The crystals belong monoclinic space group $C_2$ with $a = 21.504 \\AA$, $b = 4.779 \\AA$, $c = 8.350 \\AA$ and $\\beta = {97.63}^{\\ci...

  6. Synthesis and Structure of A Novel Quasi-Two Dimensional Organic-inorganic Hybrid Coordination Polymer:{[Cu(en)2][Ag2I4]}n

    Institute of Scientific and Technical Information of China (English)

    SUN Ling-Guo; LI Hao-Hong; CHEN Zhi-Rong; HUANG Chang-Cang; ZHAO Bin; LI Jun-Qian

    2006-01-01

    A novel coordination polymer {[Cu(en)2][Ag2I4]}n (en = ethylenediamine) was synthesized by the reaction of NaAgI2 and Cu(en)2(NO3)2·2H2O at room temperature with pH = 6.0, and the structure was characterized by X-ray single-crystal diffraction. It crystallizes in monoclinic, space group C2/m, with a=10.646(2), b = 13.304(3), c = 6.8445(14)(A), β = 118.95(3)°, C4H16N4CuAg2I4, Mr = 907.10, V = 848.3(4)(A)3, Z = 2, Dc = 3.551 g/cm3, F(000) = 806, μ(MoKα) = 10.787 mm(1, the final R1 = 0.0256 and wR2 = 0.0654 for 900 observed reflections with I > 2σ(I). According to structural analysis, the title compound consists of template cation [Cu(en)2]2+ and inorganic chain [Ag2I4]n2-. The polymeric negative chain [Ag2I4]n2- is built up from pairs of AgI4 tetrahedron by sharing one edge. Through N-H…I hydrogen-bonding interactions, the whole structure represents a quasi-two dimensional arrangement. Electrostatic attraction exists between organic cations and inorganic chains, leading to a so-called organic-inorganic hybrid structure.

  7. Synthesis and Uncommon Structural Characterization of Novel Zinc and Cadmium Complexes with Imino Nitroxide Radical

    Institute of Scientific and Technical Information of China (English)

    WANG Shu-Ping; GAO Dong-Zhao; LIAO Dai-Zheng; JIANG Zong-Hui; YAN Shi-Ping

    2007-01-01

    Two novel complexes {[Zn(IM4py)2(tp)(H2O)]·2H2O}n 1 and {[Cd(IM4py)2(tp)- (H2O)]·1.25H2O}n 2 (IM4py=2-(4'-pyridinyl)-4,4,5,5-tetramethylimidazoline-1-oxyl and tp=terephthalate dianion) have been synthesized and characterized by elemental analyses, IR spectrum and single-crystal X-ray diffraction. Crystal data for complex 1: monoclinic, space group C2/c, a=20.648(7), b=12.130(4), c=14.036(4) (A), β=106.351(5)°, C32H42N6O9Zn, Mr=720.09, V=3373.3(2) (A)3, Z=4, Dc=1.418 g/cm3, μ(MoKα)= 0.790 mm-1, F(000)=1512, the final R=0.0407 and Wr=0.0894 for 3480 independent reflections with Rint=0.0432. Crystal data for complex 2: monoclinic, space group C2/c, a=21.332(6), b=12.063(3), c=14.246(4) (A), β=106.704(4)°, C32H40.50N6O8.25Cd, Mr=753.60, V=3511.2(2) (A)3, Z=4, Dc=1.426 g/cm3, μ(MoKα)= 0.679 mm-1, F(000)=1554, the final R=0.0419 and Wr=0.0961 for 3627 independent reflections with Rint=0.0440. The framework structures of complexes 1 and 2 are 3-D networks via the hydrogen bonds among 1-D chains. The notable characteristics of the two complexes are that the coordination polyhedron of Zn(Ⅱ) adopts a rare distorted five-coordinate square pyramidal geometry in 1, and the Cd(Ⅱ) complex exhibits an unusual distorted seven-coordinate pentagonal bipyramid in 2.

  8. Crystal structure of Fe(HPO sub 3 ). Structure cristalline du phosphite acide de Fe sup III , Fe(HPO sub 3 H) sub 3

    Energy Technology Data Exchange (ETDEWEB)

    Sghyar, M.; Rafiq, M. (Faculte des Sciences, Fes (Morocco). Lab. de Chimie Minerale Appliquee); Durand, J.; Cox, L. (Centre National de la Recherche Scientifique, 34 - Montpellier (France). Lab. de Physicochimie des Materiaux)

    1991-01-15

    Fe(HPO{sub 3}H){sub 3}, M{sub r}=298.8, monoclinic, Cc, a=13.619(4), b=6.422(1), c=9.699(3) A, {beta}=106.27(2)deg, V=814.3(7) A{sup 3}, Z=4, D{sub m}=2.507 (by picnometry), D{sub x}=2.438 Mg m{sup -3}, {lambda}(Mo K{alpha})=0.71069 A, {mu}=2.21 mm{sup -1}, F(000)=428, room temperature. Final R=0.051, wR=0.35 for 642 independent reflections. Fe(HPO{sub 3}H){sub 3} has been studied by single-crystal X-ray analysis with an automatic diffractometer. The structure is built up of a three-dimensional network of FeO{sub 6} octahedra and HPO{sub 3}H{sup -} tetrahedra. Three hydrogenphosphite anions are hydrogen bonded and constituted an (HPO{sub 3}H){sub 3}{sup 3-} anion. (orig.).

  9. Ab initio study of the structural phase transitions of the double perovskites Sr2MWO6 (M=Zn, Ca, Mg)

    Science.gov (United States)

    Petralanda, U.; Etxebarria, I.

    2014-02-01

    We study the interplay of structural distortions in double perovskites Sr2MWO6 (M = Zn, Ca, Mg) by means of first-principles calculations and group theoretical analysis. Structure relaxations of the cubic, tetragonal, and monoclinic phases show that the ground states of the three compounds are monoclinic, although the energy difference between the monoclinic and tetragonal structures is very small in the case of Sr2MgWO6. The symmetry analysis of the distortions involved in the experimental and calculated low-temperature structures shows that the amplitude of two primary distortions associated to rigid rotations of the MX6 and WO6 octahedra are dominant, although the amplitude of a third mode related to deformations of the MX6 groups can not be neglected. The energy maps of the space spanned by the three relevant modes are calculated, and the couplings among the modes are evaluated, showing that the role of a hard secondary mode (in the Landau sense) coupled trilinearly to the two primary instabilities is crucial to stabilize the monoclinic ground state. Results suggest that the key role of the trilinear coupling among three modes could be rather common. A phenomenological theory including the effects of the chemical pressure is also developed. We find that the evolution of the stiffness constants in terms of the atomic substitution follows an accurate linear dependence and that the influence of quantum saturation of the order parameters could stabilize the tetragonal phase of Sr2MgWO6.

  10. Rich structural phase diagram and thermoelectric properties of layered tellurides Mo{sub 1−x}Nb{sub x}Te{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Ikeura, Koji; Sakai, Hideaki [Department of Applied Physics, University of Tokyo, Hongo, Tokyo 113-8656 (Japan); Bahramy, Mohammad Saeed [Department of Applied Physics, University of Tokyo, Hongo, Tokyo 113-8656 (Japan); RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198 (Japan); Ishiwata, Shintaro, E-mail: ishiwata@ap.t.u-tokyo.ac.jp [Department of Applied Physics, University of Tokyo, Hongo, Tokyo 113-8656 (Japan); JST, PRESTO, Kawaguchi, Saitama 332-0012 (Japan)

    2015-04-01

    MoTe{sub 2} is a rare transition-metal ditelluride having two kinds of layered polytypes, hexagonal structure with trigonal prismatic Mo coordination and monoclinic structure with octahedral Mo coordination. The monoclinic distortion in the latter is caused by anisotropic metal-metal bonding. In this work, we have examined the Nb doping effect on both polytypes of MoTe{sub 2} and clarified a structural phase diagram for Mo{sub 1−x}Nb{sub x}Te{sub 2} containing four kinds of polytypes. A rhombohedral polytype crystallizing in polar space group has been newly identified as a high-temperature metastable phase at slightly Nb-rich composition. Considering the results of thermoelectric measurements and the first-principles calculations, the Nb ion seemingly acts as a hole dopant in the rigid band scheme. On the other hand, the significant interlayer contraction upon the Nb doping, associated with the Te p-p hybridization, is confirmed especially for the monoclinic phase, which implies a shift of the p-band energy level. The origin of the metal-metal bonding in the monoclinic structure is discussed in terms of the d electron counting and the Te p-p hybridization.

  11. Synthesis and crystal structure of the novel transition- metal substituted tin hydride H2Sn2[Mn(CO)5]4

    NARCIS (Netherlands)

    Bos, K.D.; Bulten, E.J.; Noltes, J.G.

    1975-01-01

    Dicyclopentadienyltin reacts with manganese pentacarbonyl hydride to give the first transition-metal substituted ditin dihydride, H[Mn(CO)5]2Sn---Sn- [Mn(CO)5]2H, the structure of which has been determined by X-ray analysis. The compound crystallizes in the monoclinic space group with four molecul

  12. Comparative analysis of the structure and morphology of a zirconia synthesized by combustion reaction with commercial zirconia; Analise comparativa da estrutura e morfologia de uma zirconia sintetizada por reacao de combustao com uma zirconia comercial

    Energy Technology Data Exchange (ETDEWEB)

    Silva, F.N.; Dantas, J.; Cunha, R.B.L.; Costa, A.C.F.M., E-mail: fnilson.s@hotmail.com [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Departamento de Engenharia de Materiais; Pallone, E.M.J.A. [Universidade de Sao Paulo (USP), Pirassununga, SP (Brazil). Departamento de Ciencias Basicas

    2013-07-01

    This work aims to obtain zirconia (ZrO{sub 2}) by combustion reaction, and to make a comparative analysis regarding the structure and morphology of a commercial monoclinic zirconia. The synthetic ZrO{sub 2} was obtained by combustion reaction in batch of 15 g of product, used as precursor the n-propoxide of zirconium IV and urea. The commercial ZrO{sub 2} was supplied by Saint-Gobain Zirpro. The samples were characterized by DRX, SEM and particle size distribution. The results showed for the synthesized ZrO{sub 2} a major phase formation of monoclinic zirconia with trace of the orthorhombic zirconia phase, with crystallite size 16 nm and crystallinity 57%. In the commercial sample was identified only the single monoclinic phase with crystallite size 39 nm and crystallinity of 86%. Both samples have shown homogeneous morphology, constituted of very fine particles of approximately hexagonal shape, with average particle size of 47 to 72 nm, for the synthesized and commercial ZrO{sub 2}, respectively. Comparing among samples, it was found that synthesis by combustion reaction was effective to get monoclinic ZrO{sub 2} nanoparticles with traces of orthorhombic phase with morphology of the finer particles than commercial monoclinic ZrO{sub 2}. (author)

  13. Solid State Structure of Poly(9,9-dinonylfluorene)

    DEFF Research Database (Denmark)

    Torkkeli, Mika; Galbrecht, Frank; Scherf, Ullrich

    2015-01-01

    We report on X-ray diffraction and grazing-incidence X-ray diffraction data of poly(9,9-dinonylfluorene) (PF9) in bulk, thin films and in the 1% methylcyclohexane gel. We denote the main crystalline phase as alpha phase and propose that the unit cell is monoclinic (a = 29.31 angstrom, b = 23...... polymer chains) and to the stacking of aromatic main chain units along the b-axis. The polymer chains are aligned along the c-axis. Monoclinic structure agrees with the layer spacing of 14.6 angstrom, the stacking period d(040) = 5.89 angstrom and the monomer repeat distance of 8.33 angstrom. The alpha...

  14. Influence of crystal structure of nanosized ZrO2 on photocatalytic degradation of methyl orange

    OpenAIRE

    Basahel, Sulaiman N; Ali, Tarek T; Mokhtar, Mohamed; Narasimharao, Katabathini

    2015-01-01

    Nanosized ZrO2 powders with near pure monoclinic, tetragonal, and cubic structures synthesized by various methods were used as catalysts for photocatalytic degradation of methyl orange. The structural and textural properties of the samples were analyzed by X-ray diffraction, Raman spectroscopy, TEM, UV-vis, X-ray photoelectron spectroscopy (XPS), and N2 adsorption measurements. The performance of synthesized ZrO2 nanoparticles in the photocatalytic degradation of methyl orange under UV light ...

  15. Structure and vibrational spectra of L-alanine L-alaninium picrate monohydrate

    Science.gov (United States)

    Ghazaryan, V. V.; Fleck, M.; Petrosyan, A. M.

    2012-05-01

    Preparation, crystal and molecular structure as well as vibrational spectra of the crystal L-alanine L-alaninium picrate monohydrate are described. The title crystal is monoclinic, space group P21. The asymmetric unit contains one dimeric (L-Ala⋯L-Ala+) cation, one picrate anion and a water molecule. The O⋯O distance in the dimeric cation is equal to 2.553(2) Å. The IR and Raman spectra are interpreted based on the structure.

  16. WMO Marine Final Reports

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Final reports of the World Meteorological Organization (WMO) Commission for Marine Meteorology, Commission for Synoptic Meteorology, and Commission for Basic...

  17. Transacsys PLC - Final Results

    CERN Multimedia

    2002-01-01

    Final results from Transacsys PLC. A subsidary of this company was set up to develop the CERN EDH system into a commercial product but incurred too much financial loss so the project was cancelled (1/2 page).

  18. Aurora final report

    Energy Technology Data Exchange (ETDEWEB)

    Robert, Dross; Amedeo, Conti

    2013-12-06

    Final Technical report detailing the work done by Nuvera and its partners to fulfill the goals of the program "Transport Studies Enabling Efficiency Optimization of Cost-Competitive Fuel Cell Stacks" (a.k.a. AURORA)

  19. Final focus test beam

    Energy Technology Data Exchange (ETDEWEB)

    1991-03-01

    This report discusses the following: the Final Focus Test Beam Project; optical design; magnets; instrumentation; magnetic measurement and BPM calibration; mechanical alignment and stabilization; vacuum system; power supplies; control system; radiation shielding and personnel protection; infrastructure; and administration.

  20. CLIC Final Focus Studies

    CERN Document Server

    Tomás, R; Schulte, Daniel; Zimmermann, Frank

    2006-01-01

    The CLIC final focus system has been designed based on the local compensation scheme proposed by P. Raimondi and A. Seryi. However, there exist important chromatic aberrations that deteriorate the performance of the system. This paper studies the optimization of the final focus based on the computation of the higher orders of the map using MAD-X and PTC. The use of octupole tail folding to reduce the size of the halo in the locations with aperture limitations is also discussed.

  1. Data breaches. Final rule.

    Science.gov (United States)

    2008-04-11

    This document adopts, without change, the interim final rule that was published in the Federal Register on June 22, 2007, addressing data breaches of sensitive personal information that is processed or maintained by the Department of Veterans Affairs (VA). This final rule implements certain provisions of the Veterans Benefits, Health Care, and Information Technology Act of 2006. The regulations prescribe the mechanisms for taking action in response to a data breach of sensitive personal information.

  2. First-principles calculations of high-pressure iron-bearing monoclinic dolomite and single-cation carbonates with internally consistent Hubbard U

    Science.gov (United States)

    Solomatova, Natalia V.; Asimow, Paul D.

    2017-08-01

    It has been proposed that iron has a significant effect on the relative stability of carbonate phases at high pressures, possibly even stabilizing double-cation carbonates (e.g., dolomite) with respect to single-cation carbonates (e.g., magnesite, aragonite and siderite). X-ray diffraction experiments have shown that dolomite transforms at 35 GPa to a high-pressure polymorph that is stable to decomposition; however, there has been disagreement on the structure of the high-pressure phase (Mao et al. in Geophys Res Lett 38, 2011. doi: 10.1029/2011GL049519; Merlini et al. in Proc Natl Acad Sci 109:13509-13514, 2012. doi: 10.1073/pnas.1201336109). Ab initio calculations interfaced with an evolutionary structure prediction algorithm demonstrated that a C2/c polymorph of pure CaMg(CO3)2 dolomite is more stable than previously reported structures (Solomatova and Asimow in Am Mineral 102:210-215, 2017, doi: 10.2138/am-2017-5830). In this study, we calculate the relative enthalpies up to 80 GPa for a set of carbonate phases including Fe-bearing solutions and endmembers, using the generalized gradient approximation and a Hubbard U parameter calculated through linear response theory to accurately characterize the electronic structure of Fe. When calculated with a constant U of 4 eV, the spin transition pressure of (Mg,Fe)CO3 agrees well with experiments, whereas an internally consistent U overestimates the spin transition pressure by 50 GPa. However, whether we use constant or internally consistent U values, a higher iron concentration increases the stability field of dolomite C2/c with respect to single-cation carbonate assemblages, but iron-free dolomite is not stable with respect to single-cation carbonates at any pressure. Thus, high-pressure polymorphs of Fe-bearing dolomite could in fact represent an important reservoir for carbon storage within oxidized sections of Earth's mantle.

  3. Hydrothermal Synthesis and Crystal Structure of a One-dimensional Copper(Ⅱ) Complex%Hydrothermal Synthesis and Crystal Structure of a One-dimensional Copper(Ⅱ) Complex

    Institute of Scientific and Technical Information of China (English)

    LI Xiu-Mei; WANG Qing-Wei; LIU Bo

    2012-01-01

    A metal-organic coordination polymer [Cu(cbba)2(bix)]n(Hcbba = 2-(4'-chlorine-benzoyl)-benzoic acid,bix = 1,4-bis(imidazol-1-ylmethyl)-benzene) 1 has been hydrothermally synthesized and characterized by elemental analysis,IR,TG,UV and single-crystal X-ray diffraction.Blue crystals crystallize in the monoclinic system,space group C2/c with a = 26.127(3),b = 10.6143(14),c = 14.5676(19) ,β = 111.289(2),V = 3764.3(8) 3,C42H30Cl2CuN4O6,Mr = 821.14,Dc = 1.449 g/cm3,F(000) = 1684,Z = 4,μ(MoKα) = 0.777 mm 1,the final R = 0.0528 and wR = 0.1200 for 2241 observed reflections(I 〉 2(I)).The structure of 1 exhibits a one-dimensional chain-like structure.

  4. Lattice dynamics and electronic structure of energetic solids LiN3 and NaN3: A first principles study

    OpenAIRE

    Babu, K Ramesh; Vaitheeswaran, G.

    2013-01-01

    We report density functional theory calculations on the crystal structure, elastic, lattice dynamics and electronic properties of iso-structural layered monoclinic alkali azides, LiN3 and NaN3. The effect of van der Waals interactions on the ground- state structural properties is studied by using various dispersion corrected density functionals. Based on the equilibrium crystal structure, the elastic constants, phonon dispersion and phonon density of states of the compounds are calculated. Th...

  5. Synthesis and Crystal Structure of a New Potassium Yttrium Diphosphate Dihydrate KYP2O7·2H2O

    Institute of Scientific and Technical Information of China (English)

    Férid M. Horchani-Naifer K

    2008-01-01

    The dihydrated potassium yttrium diphosphate, KYP2O7·2H2O, has been synthe-sized for the first time. Single-crystal XRD study has allowed the determination of its structure and correct formula. It crystallizes in the monoclinic system, space group P21/c, with the cell parameters a = 7.7069(3), b = 10.5801(4), c = 10.0204(5) ?, β = 93.24(3)°, V = 815.76(6) ?3, Z = 4, Mr = 337.98, F(000) = 656, Dc = 2.752 g/cm3 and μ = 8.073 mm-1. The single-crystal structure was solved from 1856 unique reflections with the final R = 0.0365 and wR = 0.0772, refined with 119 parameters. The atomic arrangement of KYP2O7·2H2O is built by the P2O7 groups, the YO7 and the KO10 polyhedrons which are connected by corner and edge-sharing to form a three-dimensional framework. Water molecules are directly bonded to the Y and K atoms, and they are located in channels running along the a direction.

  6. Crystal Structure and Thermal Decomposition Mechanism of [K(DNP)(H2O)0.5]n

    Institute of Scientific and Technical Information of China (English)

    MA, Gui-Xia(马桂霞); ZHANG, Tong-Lai(张同来); ZHANG, Jian-Guo(张建国); SHAO, Bing(邵兵); LI, Yu-Feng(李玉锋); SONG, Jiang-Chuang(宋江闯); YU, Kai-Bei(郁开北)

    2004-01-01

    The new coordination polymer, [K(DNP)(H2O)0.5]n (DNP=2,4-dinitrophenol) was prepared by the reaction of 2,4-dinitrophenol with potassium hydroxide. The molecular structure was determined by X-ray single-crystal diffraction analysis, FT-IR techniques, and elemental analysis. The crystal is monoclinic, space group C(2)/c with the empirical formula of C6H4N2O5.5K, Mr=231.21. The unit cell parameters are as follows: a=2.0789(3) nm, b=1.2311(2) nm, c=0.7203(1) nm, β=109.611(15)°, V=1.7366(4) nm3, Z=4, Dc=1.769 g/cm3, F(000)=936, μ (Mo Kα)=0.617 mm-1. The potassium ions coordinate with all the oxygen atoms of phenolic hydroxyl group and nitro-group of different 2,4-dinitrophenol (DNP) ligands with high coordination number, and form a good cross-linked three-dimensional net structure of which makes the complex with good stabilities. The thermal decomposition of [K(DNP)(H2O)0.5]n has only an intense exothermic process in the temperature range of 338-343 ℃ corresponding to a mass loss of 75.02%. The final decomposition residue is potassium isocyanide.

  7. Hydrothermal Synthesis, Crystal Structure and Electrochemical Properties of Complex Mn2(phen)2(p-CBA)4(H2O)

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    One novel complex Mn2(phen)2(p-CBA)4(H2O) has been hydrothermally synthesized from p-chlorobenzoic acid (p-CBA), 1,10-phenanthroline (phen) and anhydrous man-ganese(Ⅱ) sulfate and then characterized. Crystal data for this complex: monoclinic, space group C2/c, with a = 2.3416(3), b = 1.5604(2), c =1.5605(2) nm, β = 121.048(2)° , V= 4.8849(12) nm3, Dc = 1.510 g/cm3, Mr = 555.26, Z = 8, μ = 0.798 mm-1, F(000) = 2256, GOOF = 1.032, the final R = 0.0393 and wR = 0.0816. The crystal structure shows that two neighboring manganese(Ⅱ) ions are linked together by two bridge-chelating p-chlorobenzoic groups and one bridging water molecule, forming a cage structure with the Mn-Mn bond distance of 0.3512 nm. Each manganese(Ⅱ) ion is coordinated by two nitrogen atoms of one 1,10-phenanthroline molecule and four oxygen atoms from three p-chlorobenzoic acid anions and one water molecule, giving a distorted octahedral coordination geometry. The cyclic voltammetric behavior of the complex was also investigated.

  8. Hydrothermal Synthesis, Crystal Structure and Spectral Characterization of a New Copper Isopolytungstate: [Cu(phen)3][W6O19

    Institute of Scientific and Technical Information of China (English)

    MENG Fan-Xia; LIU Kun; CHEN Ya-Guang

    2006-01-01

    An unusual inorganic-organic hybrid hexatungstate complex [Cu(phen)3][W6O19] 1(C36H24 CuN6O19W6, Mr= 2011.20) was hydrothermally synthesized and characterized by singlecrystal X-ray diffraction, IR spectrum, UV-VIS spectrum and elemental analyses. This compound crystallizes in the monoclinic system, space group C2/c with a = 19.1005(11), b = 11.2585(11), c =20.2867(15) (A),β= 102.177(2)°, V= 4264.4 (A)3, μ(MoKa) = 16.691 mm-1, Dc = 3.133 g/cm3, Z= 4,F(000) = 3628, the final R = 0.0338 and wR = 0.0798 for 4090 observed reflections with 1 > 2σ(Ⅰ).The result of structure determination shows that the crystal structure is constructed from [W6O19]2-cluster anions and [Cu(phen)3]2+ complex fragments, which are held together into a three-dimensional network through hydrogen-bonding interactions.

  9. Synthesis, Crystal Structure and Quantum Chemistry Calculation of a Bis(dafone) Di(dmf) Copper(Ⅱ) Complex

    Institute of Scientific and Technical Information of China (English)

    REN Yong-Gang; CHEN Zhi-Rong; LI Hao-Hong; ZHAO Bin; HUANG Chang-Cang; LI Jun-Qian

    2005-01-01

    The title compound [Cu(dafone)2(DMF)2](2ClO4 1 (dafone = 4,5-diazafluoren- 9-one, dmf = N,N(A)-dimethyl formamide) was synthesized by the reaction of Cu(ClO4 )2 and dafone in DMF solution at room temperature with pH = 3.0.The single-crystal X-ray analysis has revealed that 1 crystallizes in monoclinic, space group P21/n with a = 8.4853(8), b = 13.1520 (14), c = 14.3866(12) (A), β = 102.629(3)o, V = 1566.7(3) (A)3, C28H26Cl2CuN6O12, Mr = 773.00, Z = 2, Dc = 1.639 g/cm3 , F(000) = 790, μ = 0.942 mm-1, the final R = 0.0438 and wR = 0.1214 for 3165 obser- ved reflections with I > 2σ(I).X-ray analysis shows that compound 1 has unsymmetric chelation of dafone with one Cu-N bond being much longer than the other.Coordination geometry of Cu is a highly distorted octahedron and the whole structure is stabilized by π-π stacking and static attractive forces from [ClO4]- anions.Based on the crystal data, quantum chemistry calculation at the DFT/ B3LPY level was used to reveal the electronic structure of 1.

  10. Synthesis and Structure of L-Aspartato-nickel(II) Complex with Benzimidazole

    Institute of Scientific and Technical Information of China (English)

    张骊; 戴志远

    2004-01-01

    The title complex Ni(C4H5NO4)(C7H6N2)3·1.75(H2O)(C25H26.5N7NiO5.75,Mr=575.74) has been prepared and its crystal structure was determined by X-ray diffraction method.The crystal of this chiral complex belongs to monoclinic,space group P21 with a=13.208(1),b=10.741(1),c=19.398(1)A,β=104.39(1)°,V=2665.8(4)A3,Z=4,Dc=1.435 g/cm3,μ(MoKα)=0.780 mm-1 and F(000)=1198.The final R=0.0504 and wR=0.1267 for 9159 observed reflections (I>2σ(I)),and R=0.065 and wR=0.1299 for 11006 independent reflections.The complex assumes a distorted octa-hedral coordinate geometry formed by one aspartate dianion and three benzimidazole ligands.The aspartate chelates to the Ni atom as a tridentate ligand.The lattice water molecules are hydrogen-bonded to the Ni complex molecule.

  11. STUDY ON SYNTHESIS AND CRYSTAL STRUCTURE OF TETRAKIS-(μ2-ACETATO-DIHYDRATE-DICOPPER(II

    Directory of Open Access Journals (Sweden)

    LI-HUA WANG

    2015-10-01

    Full Text Available A new binuclear Cu(II complex, tetrakis-(μ2-acetato-dihydrate-dicopper (II, has been prepared by the reaction of Cu(OAc2·H2O with 2-formyl-benzenesulfonate-hydrazine in the CH3CH2OH/H2O (v : v = 1 : 1. It was characterized by elemental analysis, IR and X-ray single crystal diffraction analysis. The crystal of the Cu(II complex belongs to monoclinic, space group C2/c with a = 13.162(3 Å, b = 8.5572(17 Å, c = 13.860(3 Å, β = 117.06(3 º, V = 1390.1(5 Å3, Z = 4, Dc = 1.889 μg·m-3, μ = 3.103 mm-1, F(000 = 792, and final R1 = 0.0548, wR2 = 0.1410. Two Cu(II centers are bridged by oxygen atoms of carboxylato groups. Each Cu(II center is five-coordinated with four O donor atoms of acetate and a O donor of coordinated water molecule. The molecules form three dimensional network structures by the inaction of π-π stacking and hydrogen bonds.

  12. Synthesis, Structure and Theoretical Calculation of Imidazolium 3,5-Dinitrobenzoate

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The title adduct imidazolium 3,5-dinitrobenzoate has been synthesized in aqueous solution and characterized by elemental analyses, IR spectrum and X-ray crystallography. The title compound belongs to monoclinic, space group P21/n with a = 7.5540(9), b = 21.333(2), c =7.7823(9) (A), β = 102.741(2)°, C10H8N4O6, Mr = 280.20, V = 1223.3(2) (A)3, Z = 4, Dc = 1.521 g/cm3,F(000) = 576,μ = 0.129 mm-1, the final R = 0.0433 and wR = 0.1092 for 2001 observed reflections with I > 2σ(1). The structural analysis indicates the component ions are linked by N-H…O hydrogen bonds into an infinite one-dimensional C22 (8) chain parallel to the [1 0 -1] direction. Moreover, the theoretical investigations of the title compound with HF/6-31G(d) method were performed, and its stability, frontier molecular orbital composition and Mulliken charge distribution were also discussed.

  13. Synthesis, X-ray Crystal Structure and Thermal Decomposition Mechanism of [RbHTNR]∞

    Institute of Scientific and Technical Information of China (English)

    ZHENG, Hong; ZHANG, Tong-Lai; ZHANG, Jian-Guo; QIAO, Xiao-Jing; YANG, Li; YU, Kai-Bei

    2006-01-01

    A new compound, [RbHTNR]∞ [HTNR-: C6H(NO2)3(OH)O ], was synthesized by the reaction of rubidium nitrate and styphnic acid. The molecular structure was characterized using X-ray diffraction analysis, elemental analysis and FTIR spectroscopy. The crystalline is monoclinic with space group P21/n and the empirical formula C6H2N3OsRb. The unit cell parameters are: a=0.4525 nm, b=1.0777 nm, c= 1.9834 nm, β=90.47(2)°, V=0.96725 nm3, Z=4, Dc=2.263 g/cm3, Mr=329.58, F(000)=640, μ(Mo Kα)=5.165 mm-1. The thermal decomposition mechanism of the complex was studied by differential scanning calorimetry (DSC), thermogravimetryderivative thermogravimetry (TG-DTG) and FTIR techniques. At the linear rate of 10 ℃/min, the thermal decomposition of the complex showed three mass reducing processes between 60 and 500 ℃, and finally evolved RbCN and some gaseous products.

  14. Structural analysis of Gossypium hirsutum fibers grown under greenhouse and hydroponic conditions.

    Science.gov (United States)

    Natalio, Filipe; Tahir, Muhammad Nawaz; Friedrich, Norman; Köck, Margret; Fritz-Popovski, Gerhard; Paris, Oskar; Paschke, Reinhard

    2016-06-01

    Cotton is the one of the world's most important crops. Like any other crop, cotton growth/development and fiber quality is highly dependent on environmental factors. Increasing global weather instability has been negatively impacting its economy. Cotton is a crop that exerts an intensive pressure over natural resources (land and water) and demands an overuse of pesticides. Thus, the search for alternative cotton culture methods that are pesticide-free (biocotton) and enable customized standard fiber quality should be encouraged. Here we describe a culture of Gossypium hirsutum ("Upland" Cotton) utilizing a greenhouse and hydroponics in which the fibers are morphological similar to conventional cultures and structurally fit into the classical two-phase cellulose I model with 4.19nm crystalline domains surrounded by amorphous regions. These fibers exhibit a single crystalline form of cellulose I-Iß, monoclinic unit cell. Fiber quality bulk analysis shows an improved length, strength, whiteness when compared with soil-based cultures. Finally, we show that our fibers can be spun, used for production of non-woven fabrics and indigo-vat stained demonstrating its potential in industrial and commercial applications.

  15. Synthesis, crystal structure, characterization and electrochemical properties of a new cyclohexaphosphate: Li2Na2CoP6O18·12H2O

    Science.gov (United States)

    Sleymi, Samira; Kahlaoui, Massoud; Dkhili, Samiha; Besbes-Hentati, Salma; Abid, Sonia

    2017-01-01

    A new cyclohexaphosphate with the Li2Na2CoP6O18·12H2O (LNCP) composition was prepared via a simple process at room temperature. This compound was characterized using X-ray diffraction (XRD), Infrared and UV-visible spectroscopy, Thermal analysis (TG), Cyclic voltammetry and Impedance spectroscopy. The results show that the LNCP was phased with a monoclinic structure and C2/c space group. The crystal structure was solved by using 3893 independent reflections with a final R value of 0.055. The P6O18 ring is centrosymmetrical. Its main geometrical features are those commonly observed in the atomic arrangements of cyclohexaphosphate. The atomic arrangement of this compound can be described by an organization in a three-dimensional framework, formed by the anions (P6O18)6- and polyhedra of lithium and sodium. This structure has channels where octahedral cobalt is housed. By means of a cyclic voltammetry study, it is shown that this substrate undergoes a multistep anodic oxidation, leading to a thin and compact electroactive deposit. The electrical conductivity was studied using two-probe impedance spectroscopy and results showed that the conductivity of LNCP at 518 K was equal to 1.74 × 10-4 Scm-1.

  16. Synthesis and Crystal Structure of a Coordination Polymer {[Co(phth)(phen)(H2O)]·(C2H5OH)}n

    Institute of Scientific and Technical Information of China (English)

    GAO Ling; CHENG Qing-Yan; WANG Yan-Ji

    2006-01-01

    The coordination polymer {[Co(phth)(phen)(H2O)]·(C2H5OH)}n (phth = phthalate, phen = 1,10-phenanthroline) with formula C22H20CoN2O6 (Mr = 467.33) was synthesized by the solvothermal method under low temperature, and its crystal structure was determined by singlecrystal X-ray diffraction. The complex belongs to monoclinic system, space group P21/n with a =12.7352(16), b = 8.8125(11), c = 18.677(2) (A), β = 102.633(2)°, V = 2045.3(4) (A)3, Z = 4, Dc =1.518 g/cm3,μ = 0.882 mm-1, F(000) = 964, S = 1.053, the final R = 0.0401 and wR = 0.0984 for 3135 observed reflections (I > 2σ(I)). Single-crystal X-ray analysis revealed that the Co(Ⅱ) ion is six-coordinated. The cobalt complex forms a one-dimensional chain structure via phthalate bridging ligand. In the cobalt complex, a 3D network structure is formed by π-π stacking interaction of 1,10-phenanthroline as well as intermolecular hydrogen bonding interactions.

  17. Synthesis and Crystal Structure of (E)-4-(Benzyloxy)-2-(cinnamoyloxy)-N,N,N-trimethyl-4-oxobutan-1-aminium Chloride as a Double-prodrug

    Institute of Scientific and Technical Information of China (English)

    GONG Xiao-Wei; LI Xun; LI Wei-Lu; GAO Xu; XU Wen-Fang; ZHAI Hai-Min

    2008-01-01

    A novel hydrochloride quaternary ammonium salt (E)-4-(benzyloxy)-2-(cinnamo-yloxy)-N,N,N-trimethy1-4-oxobutan-1-aminium chloride(C23H29NO4Cl2,Mr=454.37)has been synthesized via the sequence of acetylation and esterification by using L-carnitine(L-4-N-trimethy-lammonium-3-hydroxybutyric acid,LC)and cinnamic acid as the starting materials,and its crystal structure was determined by single-crystal X-ray diffraction method.The crystal belongs to monoclinic,space group P212121 with a=10.1670(4),b=10.4488(4),c=22.9795(11)(A),V=2441.18(18)(A)3,Z=4,Dc=1.236 g/cm3,μ(MoKa)=0.293 mm-1,F(000)=960,Flack factor=-0.01(11).the final R=0.0489 and wR=0.1550 for 3350 observed reflections(I>2σ(I))and R=0.0953 for all 5648 unique reflections.The crystal structure involves a conjugated system which shows a reverse olefin structure.

  18. Optical and structural characterisation of pure and Pr{sup 3+} doped LaPO{sub 4} and CePO{sub 4} nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Macalik, L., E-mail: L.Macalik@int.pan.wroc.pl [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, ul. Okolna 2, 50-422 Wroclaw (Poland); Tomaszewski, P.E. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, ul. Okolna 2, 50-422 Wroclaw (Poland); Matraszek, A.; Szczygiel, I. [Department of Inorganic Chemistry, Faculty of Engineering and Economics, Wroclaw University of Economics, ul. Komandorska 118/120, 53-345 Wroclaw (Poland); Solarz, P. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, ul. Okolna 2, 50-422 Wroclaw (Poland); Godlewska, P. [Department of Bioorganic Chemistry, Faculty of Engineering and Economics, Wroclaw University of Economics, ul. Komandorska 118/120, 53-345 Wroclaw (Poland); Sobczyk, M. [Faculty of Chemistry, University of Wroclaw, ul. F. Joliot-Curie 14, 50-383 Wroclaw (Poland); Hanuza, J. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, ul. Okolna 2, 50-422 Wroclaw (Poland); Department of Bioorganic Chemistry, Faculty of Engineering and Economics, Wroclaw University of Economics, ul. Komandorska 118/120, 53-345 Wroclaw (Poland)

    2011-07-07

    Highlights: > The nanoparticles (12-30 nm) of hydrated (hexagonal) and water-free (monoclinic) phases of lanthanum and cerium orthophosphates La(Ce)PO{sub 4} were obtained by the hydrothermal method. > Differences between hexagonal and monoclinic nanocrystals are very well reflected in the vibrational spectra and a slight influence of the environment conditions (pH) of the crystallisation is found. > The structure differences and environment conditions of the crystallisation (pH) play role in the luminescent properties. - Abstract: The rod- and stick-shaped nanocrystalline cerium and lanthanum orthophosphates, pure and Pr{sup 3+} doped, have been synthesised by the hydrothermal method in acidic (pH 1) or alkaline (pH 11) environment. Subsequent calcination of as-obtained powders at different temperatures, 500 and 900 deg. C, led to the formation of hexagonal and monoclinic phases, respectively. The hexagonal phase at room temperature has been identified as hydrated orthophosphate with zeolite water inside the channels of the structure. The monoclinic phase is free of water. The average grain size is about 12-30 nm depending on the calcination temperature and preparation conditions. The structural, morphological and optical (vibrational and luminescent) properties have been characterised and their changes due to the temperature and different acidity in the starting materials have been studied.

  19. Hydro(solvo)thermal Construction of a Copper Coordination Polymer Involving in Situ Ligand Synthesis: Preparation and Structure of [Cu3(bdcO)2(H2O)2]n

    Institute of Scientific and Technical Information of China (English)

    JIANG Ya-Qi; ZHOU Zhao-Hui; WEI Zan-Bin

    2005-01-01

    A hydro(solvo)thermal reaction of 1,3-benzenedicarboxylic acid (bdcH2) and CuSO4·5H2O produced a coordination polymer [Cu3(bdcO)2(H2O)2]n 1. The alkoxyl-1,3-benzene- dicarboxylate trianion (bdcO3-) found in the final product was in situ generated by the hydroxy- lation of bdcH2 during the synthesis. Its crystal structure has been determined by X-ray structural analysis. The complex belongs to a monoclinic system, space group P21/c with C16H10Cu3O12, Mr = 584.86, a = 5.0349(3), b = 10.422(1), c = 15.639(1) (A), β= 91.977(2)o, V = 820.1(1) (A)3, Z = 2, Dc = 2.368g/cm3, μ = 3.931 mm―1, λ(MoKα) = 0.71073 (A), F(000) = 578, the final R = 0.0328 and wR = 0.0742 for 1730 observed reflections with I≥2σ(I). The copper atoms show different coordination environments. Each bdcO group is binds to three copper atoms through oxygen atoms of carboxy- lates and deprononated hydroxy group in bridging and chelating fashions, affording a copper atom coordinated by two [Cu2(bdcO)2]2- 'matallo-ligand' to yield an extending zigzagged layer perpen- dicular to the c axis.

  20. S-SAD phasing of monoclinic histidine kinase from Brucella abortus combining data from multiple crystals and orientations: an example of data-collection strategy and a posteriori analysis of different data combinations.

    Science.gov (United States)

    Klinke, Sebastián; Foos, Nicolas; Rinaldi, Jimena J; Paris, Gastón; Goldbaum, Fernando A; Legrand, Pierre; Guimarães, Beatriz G; Thompson, Andrew

    2015-07-01

    The histidine kinase (HK) domain belonging to the light-oxygen-voltage histidine kinase (LOV-HK) from Brucella abortus is a member of the HWE family, for which no structural information is available, and has low sequence identity (20%) to the closest HK present in the PDB. The `off-edge' S-SAD method in macromolecular X-ray crystallography was used to solve the structure of the HK domain from LOV-HK at low resolution from crystals in a low-symmetry space group (P21) and with four copies in the asymmetric unit (∼108 kDa). Data were collected both from multiple crystals (diffraction limit varying from 2.90 to 3.25 Å) and from multiple orientations of the same crystal, using the κ-geometry goniostat on SOLEIL beamline PROXIMA 1, to obtain `true redundancy'. Data from three different crystals were combined for structure determination. An optimized HK construct bearing a shorter cloning artifact yielded crystals that diffracted X-rays to 2.51 Å resolution and that were used for final refinement of the model. Moreover, a thorough a posteriori analysis using several different combinations of data sets allowed us to investigate the impact of the data-collection strategy on the success of the structure determination.

  1. Click one pot synthesis, spectral analyses, crystal structures, DFT studies and brine shrimp cytotoxicity assay of two newly synthesized 1,4,5-trisubstituted 1,2,3-triazoles

    Science.gov (United States)

    Ahmed, Muhammad Naeem; Yasin, Khawaja Ansar; Ayub, Khurshid; Mahmood, Tariq; Tahir, M. Nawaz; Khan, Bilal Ahmad; Hafeez, Muhammad; Ahmed, Madiha; ul-Haq, Ihsan

    2016-02-01

    Methyl-2-(1-benzyl-4-phenyl-1H-1,2,3-triazol-5-yl)-2-oxoacetate (1) and ethyl-2-(1-benzyl-4-phenyl-1H-1,2,3-triazol-5-yl)-2-oxoacetate (2) were synthesized by one pot three component strategy, and characterized by FT-IR, NMR (1H and 13C) spectroscopy and TOF-MS spectrometry. Finally, the structures were unequivocally confirmed by single crystal X-ray diffraction analyses. Both compounds, 1 and 2 exist in monoclinic crystal packing having space group P21/n and P21/c, respectively. Crystal structures investigations revealed that the molecular structures of the title compounds are stabilized by weak intermolecular hydrogen bonding interactions to form dimers. Density functional theory (DFT) calculations were performed not only to compare with the experimental spectroscopic results but also to probe structural properties. The molecular electrostatic potential (MEP) mapped over the entire stabilized geometries of the molecules delivered information about the electrophilic and nucleophilic sites. Furthermore, frontier molecular orbital analysis gave the idea about stability and reactivity of compounds. Both compounds were also screened for brine shrimp cytotoxicity assay.

  2. Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Gilbert, Chris [Altamont Environmental, Inc.

    2014-11-13

    The project, Capital Investment to Fund Equipment Purchases and Facility Modifications to Create a Sustainable Future for EnergyXchange served to replace landfill gas energy with alternative energy resources, primarily solar and wood waste. This is the final project closeout report.

  3. CAFE Project : final report

    NARCIS (Netherlands)

    A. Weber; R. Carter; C.J. Stanford; A. Weber

    2003-01-01

    textabstract[MAS E-0302] This is the final public report of the CAFE project (ESPRIT 7023). CAFE developed a secure conditional access architecture and implemented a multi-currency electronic purse system based on smart cards and infrared wallets. The electronic purse was tested in user trials at

  4. CAFE Project : final report

    NARCIS (Netherlands)

    Weber, A.; Carter, R.; Stanford, C.J.; Weber, A.

    2003-01-01

    [MAS E-0302] This is the final public report of the CAFE project (ESPRIT 7023). CAFE developed a secure conditional access architecture and implemented a multi-currency electronic purse system based on smart cards and infrared wallets. The electronic purse was tested in user trials at the European C

  5. Structural and electronic properties of poly(vinyl alcohol) using density functional theory

    Energy Technology Data Exchange (ETDEWEB)

    Dabhi, Shweta, E-mail: shwetadabhi1190@gmail.com; Jha, Prafulla K., E-mail: shwetadabhi1190@gmail.com [Department of Physics, Maharaja Krishnakumasinhji Bhavnagar University, Bhavnagar-364001 (India)

    2014-04-24

    The first principles calculations have been carried out to investigate the structural, electronic band structure density of states along with the projected density of states for poly(vinyl alcohol). Our structural calculation suggests that the poly(vinyl alcohol) exhibits monoclinic structure. The calculated structural lattice parameters are in excellent agreement with available experimental values. The band structure calculations reveal that the direct and indirect band gaps are 5.55 eV and 5.363 eV respectively in accordance with experimental values.

  6. Polarized IR reflectance spectra of the monoclinic single crystal K2Ni(SO4)2.6H2O: dispersion analysis, dielectric and optical properties.

    Science.gov (United States)

    Ivanovski, Vladimir; Mayerhöfer, Thomas G; Popp, Jürgen; Petrusevski, Vladimir M

    2008-02-01

    Polarized IR reflectance spectra of K2Ni(SO4)2.6H2O single crystal (belonging to the group of Tutton salts) were recorded at near-normal incidence. From the dispersion analysis performed on the spectra recorded from the ac crystal plane, mode parameters: transversal frequency, oscillator strength, attenuation constant and the orientation of the transition moment were determined. The polarized spectrum along the b crystallographic axis was also recorded and a dispersion analysis performed. Comparison between the spectroscopically obtained transition moment directions with those obtained from the structure data for various modes is discussed. All dielectric tensor component values were obtained for the whole mid-IR frequency range. Also, the real and the imaginary parts of the complex indexes of refraction for the waves with wave vector in the direction of the b crystallographic axis and in the ac plane (when the direction of the electric vector is oriented along the b axis) were found as functions of frequency.

  7. Crystal structure of zirconia by Rietveld refinement

    Institute of Scientific and Technical Information of China (English)

    王大宁; 郭永权; 梁开明; 陶琨

    1999-01-01

    The crystal structures and phase transformation of zirconia ceramics have been investigated by means of X-ray powder diffraction and Rietveld powder diffraction profile fitting technique. A structural transition from monoclinic to tetragonal occurs when Y2O3 and CeO2 are doped into zirconia. The space group of the tetragonal structure is P42/nmc, Z=2. The lattice parameters are α=0.362 6(5) nm, c=0.522 6(3)nm for CeO2 doped zirconia and α=0. 360 2(8)nm, c=0. 517 9(1)nm for Y2O3 doped zirconia, respectively. In each unit cell, there are two kinds of equivalent positions, i. e. 2b and 4d, which are occupied by Zr4+, M(M=Y3+, Ce4+) cations and O2- anions, respectively. The crystallographic correlation among the cubic, tetragonal and monoclinic structures of ZrO2 is discussed.

  8. Pyroelectric properties of the monoclinic rare earth nitrates A{sub 2}Ln(NO{sub 3}){sub 5}.4H{sub 2}O (A = NH{sub 4}, Rb; Ln = La, Ce)

    Energy Technology Data Exchange (ETDEWEB)

    Ackermann, Matthias; Andersen, Lionel; Becker, Petra; Bohaty Ladislav [Koeln Univ. (Germany). Inst. fuer Kristallographie

    2015-07-01

    The pyroelectric effect of four isomorphic monoclinic (space group Cc), non-ferroelectric rare earth nitrates A{sub 2}Ln(NO{sub 3}){sub 5}.4H{sub 2}O (A = NH{sub 4}, Rb; Ln = La, Ce) was investigated in the temperature range between 100 K and 300 K, using a home-made continuous-flow cryostat for measurements of pyroelectric currents. The symmetry-allowed temperature-dependent change of orientation of the pyroelectric vector p within the mirror plane is unusually large, showing a rotation of p of 148 , 129 , 36 and 40 for (NH{sub 4}){sub 2}La(NO{sub 3}){sub 5}.4H{sub 2}O, (NH{sub 4}){sub 2}Ce(NO{sub 3}){sub 5}.4H{sub 2}O, Rb{sub 2}La(NO{sub 3}){sub 5}.4H{sub 2}O and Rb{sub 2}Ce(NO{sub 3}){sub 5}.4H{sub 2}O, respectively, while changing the temperature from 100 K to 300 K in each case. The pyroelectric coefficients are up to ten times larger than p{sub 3} of tourmaline. In addition, new data of the pyroelectric coefficients of Li{sub 2}SO{sub 4}.H{sub 2}O and BiB{sub 3}O{sub 6} and their temperature dependence are given.

  9. Preparation and structure characteristics of nano-Bi2O3 powders with mixed crystal structure

    Institute of Scientific and Technical Information of China (English)

    LI Wei

    2005-01-01

    The nano-Bi2 O3 powders were prepared by a chemical precipitation method with Bi(NO3)3, H NO3 and NaOH as reactants. The structural characteristics and morphology of nano-Bi2O3 powders were investigated by X-ray diffraction and transmission electron microscopy, respectively. The results show that under the optimum condition that 300 g/L Bi(NO3)3 reacts at 90 ℃ for 2 h, the Bi2O3 powders with 60 nm on the average and 99.5% in purity are obtained. The prepared nano-Bi2 O3 powders contain a mixed crystal structure of monoclinic and triclinic in stead of traditional structure of monoclinic α-Bi2 O3. And the mixed crystal structure is stable in air. The reason for the appearance of the mixed crystal structure may be that the ionic radius ratio of Bi3+ to O2- changes easily during the formation of nano-Bi2 O3 particles by a chemical precipitation method.

  10. Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, Mike, J., P.E.

    2012-08-30

    The STI product is the Final Technical Report from ReliOn, Inc. for contract award DE-EE0000487: Recovery Act PEM Fuel Cell Systems Providing Emergency Reserve and Backup Power. The program covered the turnkey deployment of 431 ReliOn fuel cell systems at 189 individual sites for AT&T and PG&E with ReliOn functioning as the primary equipment supplier and the project manager. The Final Technical Report provides an executive level summary, a comparison of the actual accomplishments vs. the goals and objectives of the project, as well as a summary of the project activity from the contract award date of August 1, 2009 through the contract expiration date of December 31, 2011. Two photos are included in the body of the report which show hydrogen storage and bulk hydrogen refueling technologies developed as a result of this program.

  11. CMS Is Finally Completed

    CERN Multimedia

    2008-01-01

    Yet another step in the completion of the Large Hadron Collider was taken yesterday morning, as the final element of the Compact Muon Solenoid was lowered nearly 100 meters bellow ground. After more than eight years of work at the world's most powerful particle accelerator, scientists hope that they will be able to start initial experiments with the LHC until the end of this year.

  12. Geolocation Technologies Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Magnoli, D E

    2003-06-02

    This paper is the final report for LL998 In Situ Sensing Subtask 7 (Geo-location) undertaken for NNSA NA-22 enabling technologies R&D for Counterproliferation Detection. A few state-of-the-art resolution parameters are presented for accelerometers, indoor and outdoor GPS (Global Positioning Satellite) systems, and INSs (Inertial Navigation Systems). New technologies are described, including one which has demonstrated the ability to track within a building to a resolution of under a foot.

  13. Catarse e Final Feliz

    Directory of Open Access Journals (Sweden)

    Myriam Ávila

    2001-12-01

    Full Text Available Resumo: É a certeza de que nada mais – ou nada importante – pode acontecer após o final de um conto que permite o acontecimento da catarse. Se na maioria das narrativas existe algum tipo de dénouement, em algumas delas isso acontece de maneira especialmente satisfatória e afirmativa. O conto de fadas é uma dessas formas narrativas onde o efeito catártico é extremo e preenche objetivos específicos, de acordo com Bruno Bettelheim. Hollywood mimetizou essa forma como estratégia de sedução, iniciando a tradição do final feliz no cinema. A partir do conto de fadas Cinderela, em diferentes versões, juntamente com a animação homônima da Disney e ainda duas versões do filme Sabrina, será traçada aqui uma relação entre a catarse e o final feliz nos contos de fada, bem como seu uso pela indústria cultural. Palavras-chave: catarse, contos de fada, Hollywood

  14. Structural, morphological, gas sensing and photocatalytic characterization of MoO3 and WO3 thin films prepared by the thermal vacuum evaporation technique

    Science.gov (United States)

    Arfaoui, A.; Touihri, S.; Mhamdi, A.; Labidi, A.; Manoubi, T.

    2015-12-01

    Thin films of molybdenum trioxide and tungsten trioxide were deposited on glass substrates using a simplified thermal evaporation under vacuum method monitored by heat treatment in flowing oxygen at 500 °C for 1 h. The structural and morphological properties of the films were investigated using X-ray diffraction, Raman spectroscopy, atomic force microscopy and scanning electron microscopy. The X-ray diffraction analysis shows that the films of MoO3 and WO3 were well crystallized in orthorhombic and monoclinic phase respectively with the crystallites preferentially oriented toward (2 0 0) direction parallel a-axis for both samples. In literature, we have shown in previous papers that structural and surface morphology of metal thin films play an important role in the gas detection mechanism. In this article, we have studied the response evolution of MoO3 and WO3 thin films sensors ethanol versus time, working temperature and the concentration of the ethanol. It was found that these films had high sensitivity to ethanol, which made them as a good candidate for the ethanol sensor. Finally, the photocatalytic activity of the samples was evaluated with respect to the degradation reaction of a wastewater containing methylene blue (MB) under UV-visible light irradiation. The molybdenum trioxide exhibits a higher degradation rate than the tungsten trioxide thin films under similar experimental conditions.

  15. Antitumor Metallothiosemicarbazonate:Synthesis,Crystal Structure,Spectra and Antitumor Studies of Co(Ⅲ) Complex with Thiosemicarbazone Derivative of 2-Benzoylpyridine

    Institute of Scientific and Technical Information of China (English)

    LI Ming-Xue; ZHOU Jing; WANG Zi-Liang; WANG Jing-Ping

    2008-01-01

    The title complex[Co(L)2]Cl·4H2O I has been achieved via self-assembly by incorporating cobalt into 2-benzoylpyridine thiosemicarbazonate ligand,and characterized by elemental analysis,infrared spectra,mass spectra and single-crystal X-ray diffraction study.The crystal crystallizes in monoclinic,space group P21/n,with a=10.227(3),b=17.363(4),c=17.459(4)(A),β=100.408(4)°,V=3049.2(13)(A)3,z=4,Mr=677.08,Dc=1.475 g/cm3,μ(MoKα)=0.834 mm-1,F(000)=1400,the final R=0.0747 and wR=0.0896 for 1663 observed reflections with Ⅰ>2σ(Ⅰ).The complex contains one six-coordinated cobalt ion connected by two thiosemicarbazone ligands which act as a tridentate ligand to coordinate with the center metal atoms via two pyridyl nitrogen atoms,two imine nitrogen atoms and two sulfur atoms giving rise to a mononuclear structure.Hydrogen bonds existing in the complex link the different components to stabilize the crystal structure.The antitumor activity of the title complex Was tested against A549 lung cancer cell line.Complex Ⅰ exhibits antitumor activity.

  16. A new copper(II) Schiff base complex containing asymmetrical tetradentate N2O2 Schiff base ligand: Synthesis, characterization, crystal structure and DFT study

    Science.gov (United States)

    Grivani, Gholamhossein; Baghan, Sara Husseinzadeh; Vakili, Mohammad; Khalaji, Aliakbar Dehno; Tahmasebi, Vida; Eigner, Václav; Dušek, Michal

    2015-02-01

    A new copper (II) Schiff base complex, CuL1, was prepared from the reaction of asymmetrical Schiff base ligand of L1 and Cu(OAC)2 (L1 = salicylidene imino-ethylimino-pentan-2-one). The Schiff base ligand, L1, and its copper (II) complex, CuL1, have been characterized by elemental analysis (CHN) and FT-IR and UV-vis spectroscopy. In addition, 1H NMR was employed for characterization of the ligand. Thermogrametric analysis of the CuL1 reveals its thermal stability and its decomposition pattern shows that it is finally decomposed to the copper oxide (CuO). The crystal structure of CuL1 was determined by the single crystal X-ray analysis. The CuL1 complex crystallizes in the monoclinic system, with space group P21/n and distorted square planar coordination around the metal ion. The Schiff base ligand of L1 acts as a chelating ligand and coordinates via two nitrogen and two oxygen atoms to the copper (II) ion with C1 symmetry. The structure of the CuL1 complex was also studied theoretically at different levels of DFT and basis sets. According to calculated results the Csbnd O bond length of the salicylate fragment is slightly higher than that in the acetylacetonate fragment of ligand, which could be interpreted by resonance increasing between phenyl and chelated rings in ligand in relative to the acetylacetonate fragment.

  17. Hydrothermal Synthesis,Crystal Structure and Thermal Stability of a Supramolecular Lead(II) Complex with 4-Nitrobenzoic Acid and 1,10-Phenanthroline

    Institute of Scientific and Technical Information of China (English)

    徐相君; 吴向阳; 徐婉珍; 周威; 闫永胜

    2012-01-01

    A new complex [Pb(phen)2(4-NBA)]2·2(NO3)·H2O(phen = 1,10-phenanthroline,4-NBA = 4-nitrobenzoate) has been hydrothermally synthesized and structurally determined by single-crystal X-ray diffraction,elemental analyses and IR spectroscopy.The complex crystallizes in monoclinic,space group P21/c with a = 13.416(3),b = 14.065(3),c = 16.845(3)(A°) ,β = 110.55(3)o,V = 2976.5(10)(A°)^3,Z = 2,Dc = 1.796 g/cm^3,F(000) = 1564,GOOF = 0.962,the final R = 0.0686 and wR = 0.1746.The crystal structure shows that the lead ion is coordinated with two carboxylate O atoms from the 4-NBA anion,and four N atoms from two phen molecules,forming a slightly distorted pentagonalbipyramidal coordination geometry.It is further extended by various supramo-lecular interactions to form a three-dimensional supramolecular network.The TG analysis result shows that this complex begins decomposing at 30 ℃ and decompounding completely at 733 ℃.

  18. Synthesis and Crystal Structure of 4,6-Di-tert-butyl-2-hydroxy-3-(N-1-phenylethyliminomethyl)phenyl bis(triphenylphosphine)palladium bromide

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The title compound (C59H60BrNOP2Pd, Mr=1047. 3) was synthesized in good yield from α-methylbenzylamine and 4,6-di-tert-butyl-3-formyl-2-hyd roxyphenyl bis( triphenylphosphine)palladium bromide. The latter was obtained from 3-bromo-4,6 -di -tert-butyl-2-hydroxybenzaldehyde and tetrakis(triphenylphosphine)palladium. It crystallizes in monoclinic space group P21/c with the cell dimensions a= 17.882(4 ), b=11.065(2), c=26.143(5)(A), β=90.55(3)°, V=5173(3)(A)3, Z=4, Dc=1.233g cm-3, F(00 0)=2160, μ=1.233 mm-1. The structure was solved by direct methods and r efined by full matrix least-square method, and the final crystallographic discrepancy fa c tor is 0.0647 for 5467 observed reflections. The crystal structure determination of the title compound shows that the coordination environment around the Pd cen tre is tetragonal with two Pd-P bonds of 2.333(2)(A)and 2.339(2)(A), respectively , a Pd-Br length of 2.536(1) and a Pd-C bond of 2.032(8).

  19. Hydrothermal Synthesis and Structure of a New Two- dimensional Zincophosphite:Zn2(HPO3)3(H2DACH (DACH = 1,2-diaminocyclohexane)

    Institute of Scientific and Technical Information of China (English)

    潘建新; 郑寿添; 杨国昱

    2004-01-01

    A new open-framework zincophosphite, Zn2(HPO3)3(H2DACH 1, was hydrothermally synthesized in the presence of 1,2-diaminocyclohexane (DACH) as structure-directing agent. Its structure was determined by single-crystal X-ray diffraction and further characterized by FTIR, elemental analysis, powder X-ray diffraction and thermogravimetric analysis. Crystal data for 1: Mr = 486.88, monoclinic, space group P21/c with a = 10.2287(11), b = 9.7624(11), c = 16.1686(18) A,β = 92.573(2), V = 1612.9(3) A3, Z = 4, Dc = 2.005 g/cm3, F(000) = 984, μ = 3.314 mm-1 and S = 1.152. The final R = 0.0473 and wR = 0.1121 for 2456 observed reflections with I > 2σ(I). The inorganic layer consisting of four- and eight-membered rings is constructed of alternating ZnO4 tetrahedra and HPO3 pseudo pyramids by sharing vertices. The organic template molecules reside in the interlayer region and interact with the inorganic network through H-bonds.

  20. Crystal Structure and Spectroscopic Properties of the Donor-acceptor Complex of 2-Amino-1,3-benzo- thiazole with Ethyl-5,6-benzocoumarin-3-carboxylate

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The donor-acceptor complex derived from 2-amino-1,3-benzothiazole (ABT) and ethyl 5,6-benzocoumarin-3-carboxylate (EBCC) has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/c, with a = 8.6485(3), b = 7.7743(3), c = 29.1963(10) (A), β = 92.0460(10)°, Z = 4, Mr = 418.45, V = 1961.79(12)(A)3, Dc = 1.417 g/cm3, μ = 0.199 mm-1, F(000) = 872, the final R = 0.0350 and wR = 0.1226. The complex is an A…D…D'…A' H-bonded tetramer. The intermolecular N-H…O and N-H…N hydrogen bonds, together with π-π stacking interactions, stabilize the crystal structure by forming a supramolecular architecture. It is found that, in solid state, the fluorescence emission of the complex is quenched significantly while the UV-vis spectrum exhibits a broad band at 346 nm with shoulder, which can be attributed to the donor-acceptor complex formed.

  1. Synthesis and Crystal Structure of 3,6-Bis(4,4,4-trifluorobutane-1,3-dione)-9-n-butylcarbazole

    Institute of Scientific and Technical Information of China (English)

    YANG Lin; ZHAO Xiang-Hua; ZHOU Hong-Ping; WU Jie-Ying; YANG Jia-Xiang; SHAO Guo-Quan; CHENG Le-Hua; TIAN Yu-Peng

    2008-01-01

    A novel bis(β-diketonate)derivate,3,6-bis(4,4,4-trifluorobutane-l,3-dione)-9-n-butylcarbazole 1,was synthesized and structurally characterized by single-crystal X-ray diffrac-tion.The crystal belongs to the monoclinic system,space group P21/c with a=10.961(6),b=22.942(13),C=9.408(6)(A),α=90,β=109.663(9),γ=90°, V=2228(2)(A)3,Z=4,Dc=1.489g/cm3,C24H19F6NO4,Mr=499.40,F(000)=1024 and μ=0.134mm-1.The structure was refined to the final R=0.0699 and wR=0.1627 for 3744 independent reflections(Rint=0.1288)and 1349observed reflections(I>2o(I)).Compound 1 consists of carbazole unit and two terminal diketonate groups,in which carbazole and its two adjacent diketonate rings are almost coplanar.Moreover,compound 1 was characterized with IR,elemental analysis,1H NMR,MS,electronic absorption,and single-photon fluorescence.

  2. Synthesis and Structure of a La(Ⅲ)Complex of 1,10-Phenanthroline-2,9-dicarboxylate: a Three dimensional Network via Hydrogen Bonding Interactions

    Institute of Scientific and Technical Information of China (English)

    GAO Qian; XIE Ya-Bo; CHEN Yuan; WANG Dao

    2008-01-01

    A new La(Ⅲ)complex,{[La(L)(NO3)(H2O)3]·H2O}n(L=l,10-phenanthroline-2,9-dicarboxylate),has been synthesized and structurally determined by X-ray diffraction analysis.The complex crystallizes in the monoclinic system,space group P21/c with a=7.7358(17),b=8.1664(18),c=28.271(6)(A),β=95.184(4)°,V=1778.6(7)(A)3,z=4,C14H14LaN3O11,Mr=539.19,Dc=2.014 g/cm3,μ=2.471 mm-1,F(000)=1056,the final R=0.0350 and wR=0.0659.In this complex,each metal center adopts a ten-coordination geometry formed by two N atoms from a ligand L and eight O atoms from three H2O molecules,a nitrate ion and carboxylates of two Hgands.Each ligand adopts a N2,O3-pentdentate coordination mode using two N and two O atoms chelating a La(Ⅲ),and using another O atom of carboxylate to bridge another La(Ⅲ)center resulting in a ID helical chain molecule.Intermolecular strong O-H…O and weak C-H…O hydrogen bonds extend the ID chain structure into a 3D supramolecular architecture.

  3. Synthesis and Crystal Structure of a New Zn(II) Nitronyl Nitroxide Complex [Zn(NIT4Py)(PDA)(H2O)3

    Institute of Scientific and Technical Information of China (English)

    GAO Dong-Zhao; WANG Shu-Ping; CHEN Jin; LI Li-Cun; LIAO Dai-Zheng; JIANG Zong-Hui; YAN Shi-Ping

    2006-01-01

    A new Zn(II) nitronyl nitroxide complex [Zn(NIT4Py)(PDA)(H2O)3] (NIT4Py = 2-(4'-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, H2PDA = pyridine-2,5-dicarboxylic acid) has been synthesized and structurally characterized by X-ray diffraction. It crystallizes in monoclinic, space group P21/c with a = 16.881(8), b = 7.356(4), c = 18.857(9)(A), β= 108.616(6)°, V = 2219.1(19)(A)3, C19H25N4O9Zn, Mr = 518.80, Dc = 1.553 g/cm3, μ(MoKα) = 1.165 mm-1, F(000) = 1076, Z = 4, the final R = 0.0269 and wR = 0.0715 for 3193 observed reflections with I > 2σ(I). The complex exists as discrete mononuclear molecules and the zinc(II) ion is six-coordinated with one radical ligand (NIT4Py), one bidentate pyridine-2,5-dicarboxylate anion and three water molecules. A three-dimensional network structure is formed through the intermolecular interactions.

  4. What is a twin structure? An answer from microcline minerals from pegmatites

    OpenAIRE

    Sánchez Muñoz, Luis; Crespo Feo, Elena; García-Guinea, Javier; Moura, Odulio J. M. de; Zagorsky, Victor Ye.

    2009-01-01

    Twin-structures in microcline specimens from granite pegmatites were studied by polarized light microscopy (PLM) and Raman microprobe (RMP) spectra. Ordinary and diagonal Albite-Pericline orientation variants from transformation twinning (after a monoclinic precursor) and subsequent solid-state recrystallization twinning were observed. They exhibit a ¿complexity¿, related to the particular organizations of the twin units, that is totally expected from traditional crystallographic and equilibr...

  5. Hydrothermal synthesis, structure and characterization of new NASICON related potassium iron (III) pyrophosphate

    Indian Academy of Sciences (India)

    G S Gopalakrishna; B H Doreswamy; M J Mahesh; M Mahendra; M A Sridhar; J Shashidhara Prasad; K G Ashamanjari

    2005-02-01

    A new potassium iron (III) pyrophosphate was synthesized by hydrothermal technique and characterized by X-ray studies. The compound crystallizes in a monoclinic space group, 21/, with cell parameters, = 7.365(2) Å, = 10.017(2) Å, = 8.214(1) Å, = 106.50(1)° and = 4. The structure has tunnel-type cavities and are congenial for ion transportation through them. The compound exhibits moderate thermal stability.

  6. Crystal structure and luminescence spectra of Eu(DBM)3 4,4’-BIPY complex

    Institute of Scientific and Technical Information of China (English)

    王明昭; 金林培; 王哲民; 蔡冠梁; 张家骅

    1995-01-01

    The title complex,C55H41O6N2Eu,Mr=979.91,crystallizes in the monoclinic space group C2/cwith a=2.0413(4),b=2.5556(5),c=0.8926(3)nm,β=104.64(2)°,μ=14.44cm-1,T=295K and the finalR=0.043.The structure was solved by the heavy-atom method and refined by the full-matrix least-squarestechnique for 64 non-hydrogen atoms anisotropicaUy for 2180 reflections with I≥3σ(I).The title complexforms one-dimensional chains through C-C bonds between pyridine rings of 4,4’-bipyridine.The centralEu(Ⅲ)ion is coordinated to six oxygen atoms and two nitrogen atoms and its polyhedron is a distorted squareantiprism.The high resolution laser excited excitation and luminescence spectra show that the complex pos-sesses two Eu(Ⅲ)sites with the energy difference 39 cm-1of 5D0 levels in excited state.The radiationless energytransfer to a great extent between the two Eu(Ⅲ)sites and the dominant luminescence of Eu(Ⅲ)site withlower energy as the complex was excited have been supported by the selectively excited luminescence spectra,time-resolved luminescence spectra and selectively excited luminescence decay curves.

  7. Crystal structure of a mixture of lupeol-acetate tautomers isolated from Hieracium plumulosum A. Kerner, Asteraceae

    Science.gov (United States)

    Argay, Gy.; Kálmán, A.; Kapor, A.; Ribár, B.; Petrović, S.; Gorunović, M.

    1997-11-01

    Transparent single crystals obtained from the purified extract of the plant Hieracium plumulosum A. Kerner, Asteraceae were submitted to spectroscopic and X-ray studies. The spectroscopic (infra-red, mass spectrometry, 1H and 13C nuclear magnetic resonance) investigations suggested the presence of two isomers of lupeol acetate (C 32H 52O 2) with tautomeric relationship. Their mixture crystallizes in the monoclinic system with space group P2 1: a = 19.170(2) Å, b = 8.128(1) Å, c = 21.832(2) Å, β = 90.24(1)°, V = 3401.7(6) Å3, Z = 4 (two molecules in the asymmetric unit), Dx = 1.095 gcm-3, μ(Cu Kα) = 0.488 mm -1. The structure was solved by direct methods and refined to a final R = 0.071 for 6636 reflections with I > 2 σ( I). The bond lengths around {C20 }/{( C60) } are between single and double bonds indicating the superposition of the tautomers, i.e., lup-20(29)-en-3β-ol and lup-19(20)-en-3β-ol acetates. They are distributed with different ratio in the symmetry-independent positions. In addition, the difference maps revealed that toluene solvent molecules are also captured in the lattice. They substantially hindered the refinement of atomic positions in particular for the {C19 }/{( C59) } functions.

  8. Synthesis and Crystal Structure of [CpRu(η5-C5H5)(dppc)Cl][PF6

    Institute of Scientific and Technical Information of China (English)

    WU Xiang-Hua; YU Guang-Ao; MENG Xiang-Gao; CHEN Yan; REN Yong; LIU Sheng-Hua

    2006-01-01

    The title complex [Ru(η5-C5H5)(dppc)Cl][PF6] has been synthesized by the reaction of [Ru(η5-C5H5)(PPh3)2Cl] with [dppc][PF6] (1,1'-bis(diphenylphosphino)cobaltocenium hexaflurophospate) in CH2Cl2, and its crystal structure was determined by single-crystal X-ray diffraction analysis. It crystallizes in monoclinic, space group P21/n with a = 15.754(8), b =13.704(7), c=19.120(10) (A),β=106.148(9)°, V=3965(4) (A)3, Z=4, C40H35Cl3CoF6P3Ru, Mr=988.94, Dc=1.657 g/cm3, F(000) = 1984 and μ(MoKα) = 1.181 mm-1. The final R = 0.0425 and wR = 0.1001 for 7002 independent reflections. The title complex shows a mononuclear Ru(Ⅱ)capped by an η5-Cp ring, a chelating η2-dppc and a terminal chloride to assume a three-legged piano-stool configuration.

  9. Synthesis and Crystal Structure of Diethyl 5-Acetoxy-3-(4-chlorophenyl)-4,5-dihydroisoxazol-5-yl-5-phosphonate

    Institute of Scientific and Technical Information of China (English)

    SHANG Zhi-Qiang; CHEN Ru-Yu; HUANG You

    2006-01-01

    The crystal structure of the title compound, diethyl 5-acetoxy-3-(4-chlorophenyl)-4,5-dihydroisoxazol-5-yl-5-phosphonate (Ci5H19ClNO6P, Mr = 375.73), has been synthesized by the treatment of nitrile oxides and 1-acetyloxy-vinylphosphonate under very mild conditions in good yields, and determined by single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group C2/c with a = 16.914(10), b = 10.567(7), c = 21.927(13)(A),β = 110.249(11)°, V= 3677(4)(A)3,Z = 8, Dc = 1.358 g/cm3, F(000) = 1568, μ(MoKa) = 0.324 mm-1, S = 1.011, the final R = 0.0661and wR = 0.1556. The X-ray analytic results showed that the dihedral angle between the phenyl group and the isoxazoline ring is 10.7°.

  10. Hydrothermal Synthesis, Crystal Structure and Thermal Analysis of a Dinuclear Complex Cd2(3,5-Dinitrobenzoate)4(pyridine)4

    Institute of Scientific and Technical Information of China (English)

    GUO Jin-Yu; ZHANG Tong-Lai; ZHANG Jian-Guo; LIU Yan-Hong; QIAO Xiao-Jing; YANG Li

    2006-01-01

    A dinuclear complex Cd2(dnba)4(pyridine)4 (dnba = 3,5-dinitrobenzoate) has been synthesized by hydrothermal method and characterized by X-ray single-crystal diffraction, elemen- tal analysis, FT-IR spectroscopy, DSC and TG-DTG techniques. The complex with empirical formula C48H32Cd2N12O24 (Mr = 692.83) crystallizes in monoclinic, space group P21/n with a = 12.0344(14), b = 10.5752(13), c = 21.578(3) (A), β = 104.150(2)o, V = 2662.8(6) (A)3, Z = 2, Dc = 1.728 g/cm3, μ(MoKα) = 0.897 mm-1, F(000) = 1384, S = 1.016 and (Δ/σ)max = 0.001. R = 0.0638 and wR = 0.0737 for all data; the final R = 0.0337 and wR = 0.0644. In this complex, four carboxylates are bidentate- or chelate-coordinated with the Cd(Ⅱ) centers to give the dinuclear structure. The other coordination positions of Cd(Ⅱ) are occupied by the lone pair electrons from N of four pyridines. Thermal analyses DSC and TG-DTG have been used to determine the thermal decomposition mechanism of the title complex.

  11. Synthesis and Structure of Bis—(o—vanillin)di—pyridine Nickel(Ⅱ)—pyr

    Institute of Scientific and Technical Information of China (English)

    孙命; 翁林红; 等

    2001-01-01

    The structure of the complex bis-(o-vanillin) di-pyridine nickel(Ⅱ)([Ni(C8H7O3)2(C5H5N)2]·2H2O·C5H5N,Mr=634.31)has been synthesized and determined by X-ray analysis.The crystal data are as follows:Monoclinic,P21/n,α=12.273(1),b=17.470(1),c=14.731(1)°/A,β=98.45(1),V=3125.8(3)°/A3,Z=4,Dc=1.34mg·m-3,μ=0.674mm-1,F(000)=1328,final R=0.0428,Rω=0.1228 for 4528 observable reflections with I≥2σ(I).The Nickel(Ⅱ)atom in the complex has a slightly distorted octahedral coordination geometry and is six-coordinated by four O atoms from two O-Vanillin ligands and two N atoms from two pyridines.In the crystal,the Ni(Ⅱ)-complex and water molecules are linked through a network of hydrogen bonds.

  12. Synthesis,Crystal Structure and Antimicrobial Property of 4-Bromo-2-[(3-methypyridin-2-ylimino)methyl]phenol

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li; LI Kang-Lan

    2008-01-01

    The title Schiff base compound 4-bromo-2-[(3-methylpyridin-2-ylimino)me-thyl]phenol was prepared and structurally characterized by elemental analysis,IR spectrum,and single-crystal X-ray diffraction.The crystal belongs to monoclinic,space group P21/n,with a=4.4870(9),b=19.953(4),c=13.860(3)(A),β=93.13(3)°,V=1239.O(4)(A)3,Z=4,Dc=1.561g/cm3,C13H11BrN2O2,Mr=291.15,μ=3.302mm-1 and F(000)=584.The final refinement gave R =0.0608 and wR=0.1377 for 1329 observed reflections with I>2σ(I).X-ray diffraction reveals that the non-hydrogen atoms in the compound are nearly coplanar,with the mean deviation of 0.0197 (A) from the plane.The molecule adopts an E configuration about the central C=N functional bond.The compound possesses moderate antimicrobial property.

  13. 2-D Metal Organic Structure Based on Dipyrazolate Ligand through Ni...N and Ni...H-N Interactions

    Institute of Scientific and Technical Information of China (English)

    SHAO Ying; QIN Lin; YUShu-Yan

    2012-01-01

    By employing functional ligand 3,6-bis(3,5-dimethyl-lH-pyrazol-4-yl)-9-methyl- 9H-carbazole, a novel luminescent Ni complex has been obtained. Its structure was characterized by single-crystal X-ray diffraction analysis. Crystal data: monoclinic, space group P2/c, a = 13.4224(18), b = 13.759(2), c = 8.0633(17)/~, fl = 96.448(3)~, C23H23NsNi(NO3)2, M,. = 552.19, V = 1479.7(4) A3, Z = 2, Dc = 1.239 g/cm3,/ffMoKa) = 0.700 mm-1, F(000) = 572, the final R = 0.0566 and wR = 0.1336 for 1638 observed reflections with I 〉 2a(/). X-ray analysis indicates that each metal center coordinates with two N and two H atoms in tetrahedral interaction geometry. Weak interaction between Ni and N atom of pyrazole ligand and agostic bond (Ni...H-N interaction) play important roles in the formation of the 2-dimension framework. Significantly, this framework could pack into a tubular channel with NO3 anions trapped inside.

  14. Structural, electronic properties and enhancement of electrical polarization in Er2NiMnO6/La2NiMnO6 superlattice by first-principles calculations

    Directory of Open Access Journals (Sweden)

    Haipeng Lu

    2016-03-01

    Full Text Available Employing first-principles calculations, structural, electronic properties of new multiferroic material Er2NiMnO6/La2NiMnO6 perovskite superlattice are investigated. This structure is computed as monoclinic phase with obvious distortion. The average in-plane anti-phase rotation angle, average out-of-plane in-phase rotation angle and other microscopic features are reported in this paper. Ni and Mn are found in this superlattice that stay high spin states. These microscopic properties play important roles in multiferroic properties. Based on these microscopic features, the relationship between the direction of spontaneous polarization and the order of substitution in neighboring A-O layers is explained. Finally, we try to enhance the electrical polarization magnitude by 32% by altering the previous superlattice as LaEr2NiMnO7 structure. Our results show that both repulsion force of A site rare earth ions and the arrangement of B site ions can exert influences on spontaneous polarization.

  15. Synthesis, Crystal Structure and Properties of a Dinuclear Cobalt(II) Complex [Co2(a-furacrylato)4(Phen)2(H2O)]·C2H5OH%Synthesis, Crystal Structure and Properties of a Dinuclear Cobalt(II) Complex [Co2(a-furacrylato)4(Phen)2(H2O)]·C2H5OH

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shao-Hua; YANG Ying-Qun; LI Wei

    2012-01-01

    A dinuclear cobalt(II) complex [Co2(a-furacrylato)4(Phen)2(H20)]'C2HsOH has been synthesized with a-furacrylic acid and 1,10-phenanthroline as the ligands, and its crystal structure was determined. The crystal is of monoclinic system, space group C2/c with a = 1.07388(8), b = 2.4300(2), c = 1.86708(14) nm, β= 104.3830(10)°, V= 4.719.4(7) nm3, Dc = 1.503 g/cm3, Z = 2, F(000) = 2196, GOOF = 1.053, the final R = 0.0343 and wR = 0.0883. The crystal structure shows that two neighboring cobalt(II) ions are linked by the bridging coordination of two a-furacrylic acid anions and one water molecule, and their end positions are respectively coordinated with two 1,10-phenanthroline molecules and two a-furacrylic acid anions, forming a dinuclear structure. Both cobalt(II) ions adopt hexa-coordinated distorted octahedral geometry. The electrochemical and fluorescence properties of the title complex are also discussed.

  16. Technical Report - FINAL

    Energy Technology Data Exchange (ETDEWEB)

    Barbara Luke, Director, UNLV Engineering Geophysics Laboratory

    2007-04-25

    Improve understanding of the earthquake hazard in the Las Vegas Valley and to assess the state of preparedness of the area's population and structures for the next big earthquake. 1. Enhance the seismic monitoring network in the Las Vegas Valley 2. Improve understanding of deep basin structure through active-source seismic refraction and reflection testing 3. Improve understanding of dynamic response of shallow sediments through seismic testing and correlations with lithology 4. Develop credible earthquake scenarios by laboratory and field studies, literature review and analyses 5. Refine ground motion expectations around the Las Vegas Valley through simulations 6. Assess current building standards in light of improved understanding of hazards 7. Perform risk assessment for structures and infrastructures, with emphasis on lifelines and critical structures 8. Encourage and facilitate broad and open technical interchange regarding earthquake safety in southern Nevada and efforts to inform citizens of earthquake hazards and mitigation opportunities

  17. Hughes Associates Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Olson, Brad [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2013-05-22

    This report focuses on the more limiting gasket material (neoprene and viton). The use of polymer based gasketing material has led the DOE to question whether the ducts will be able to maintain structural integrity during a fire.

  18. Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Sobecky, Patricia A; Taillefert, Martial

    2013-03-29

    This final technical report describes results and findings from a research project to examine the role of microbial phosphohydrolase enzymes in naturally occurring subsurface microorganisms for the purpose of promoting the immobilization of the radionuclide uranium through the production of insoluble uranium phosphate minerals. The research project investigated the microbial mechanisms and the physical and chemical processes promoting uranium biomineralization and sequestration in oxygenated subsurface soils. Uranium biomineralization under aerobic conditions can provide a secondary biobarrier strategy to immobilize radionuclides should the metal precipitates formed by microbial dissimilatory mechanisms remobilize due to a change in redox state.

  19. Service dogs. Final rule.

    Science.gov (United States)

    2012-09-05

    The Department of Veterans Affairs (VA) amends its regulations concerning veterans in need of service dogs. Under this final rule, VA will provide to veterans with visual, hearing, or mobility impairments benefits to support the use of a service dog as part of the management of such impairments. The benefits include assistance with veterinary care, travel benefits associated with obtaining and training a dog, and the provision, maintenance, and replacement of hardware required for the dog to perform the tasks necessary to assist such veterans.

  20. Prometheus Project final report

    Science.gov (United States)

    Taylor, Randall

    2005-01-01

    This Final Report serves as an executive summary of the Prometheus Project's activities and deliverables from November 2002 through September 2005. It focuses on the challenges from a technical and management perspective, what was different and innovative about this project, and identifies the major options, decisions, and accomplishments of the Project team as a whole. However, the details of the activities performed by DOE NR and its contractors will be documented separately in accordance with closeout requirements of the DOE NR and consistent with agreements between NASA and NR.