WorldWideScience

Sample records for nasicon type structure

  1. Polarization phenomena in romboedric structures of NASICON

    In given article peculiarities of polarization phenomena in Na3Cr2(PO4)3 of structured NASICON type are considered. On analysis base features and parameters of the process relaxational polarization in joining the structured NASICON type is revealed. Factors explaining relaxational polarization in α'-dielectric and in β-conducting phase of join from given structured type are presented. (author)

  2. Crystal structure investigation of ternary molybdate of potassium - manganese - zirconium with the Nasicon type structure

    The composition and crystal structure of the K0.52(Mn0.47Zr0.45)2(MoO4)3 ternary molybdate are clarified according to the X-ray data. The trigonal elementary cell metrics constitutes: a = b = 9.474(1), c = 24.371(4) A, Z =6, ρcal = 3.337 g/cm3, sp. gr. R3-barc. The crystalline structure constitutes the three-dimensional mixed skeleton from the (Mn, Zr)O6 octahedrons and MoO4 tetrahedrons with common oxygen apexes, in the large channels whereof the potassium atoms are positioned and it is related to the Nasicon structural type

  3. Trivalent praseodymium ion conducting solid electrolyte composite with NASICON type structure

    New trivalent praseodymium ion (Pr3+) conducting solid electrolyte composites, (PrxZr1-x)4/(4-x)Nb(PO4)3 (0.05≤x≤0.3)+NbPO5, were successfully developed by selecting the NASICON type structure as the mother structure candidate. The 94±5% praseodymium ion in the composites was identified to hold the trivalent state by effective magnetic moment measurements and the pure Pr3+ ion conduction in the composite solid was demonstrated both by ac conductivity measurements in various oxygen partial pressures and by dc electrolytes

  4. New trivalent ion conducting solid electrolyte with the NASICON type structure

    New trivalent ion conducting solid electrolytes with NASICON type structure, [(Ce1-xLax)0.1Zr0.9]40/39Nb(PO4)3, were successfully developed and their ion conducting behaviors were investigated. Among the [(Ce1-xLax)0.1Zr0.9]40/39Nb(PO4)3 series prepared, the highest ion conductivity was obtained for [(Ce1-xLax)0.1Zr0.9]40/39Nb(PO4)3 (x=0.8). The trivalent ion conductivity was approximately four times higher than that of cerium (Ce3+) ion conducting (Ce0.1Zr0.9)40/39Nb(PO4)3, and the values exceeded the region of the representative divalent oxide anion conductors such as yttria stabilized zirconia (YSZ) and calcia stabilized zirconia (CSZ) at temperatures below 500 deg. C

  5. LiTi 2(PO 4) 3 with NASICON-type structure as lithium-storage materials

    Wang, G. X.; Bradhurst, D. H.; Dou, S. X.; Liu, H. K.

    LiTi 2(PO 4) 3 with a Na + superionic conductor (NASICON)-type structure is prepared by a two-step solid-state reaction. X-ray diffraction (XRD) confirms that the LiTi 2(PO 4) 3 compound has a NASICON structure, i.e. rhombohedral (space group: R3 c). It is found that lithium can be electrochemically inserted into the LiTi 2(PO 4) 3 structure, with a maximum intake of 5.2 mol of lithium per mole of LiTi 2(PO 4) 3 compound, and that [PO 4] tetrahedra can participate in the redox reaction. This corresponds to a lithium-storage capacity of 360 mAh g -1. The kinetic parameters of lithium insertion in LiTi 2(PO 4) 3 NASICON are determined by means of ac impedance technique. The charge-transfer resistance ( RCT) and exchange current density ( i0) are invariable regardless of the state of lithium insertion. This is associated with the unique structure characteristics of the NASICON skeleton. By contrast, the diffusion coefficient, DLi of lithium varies with the state of lithium insertion. The value of DLi is in the range 1.4×10 -11 to 1.2×10 -9 m 2 s -1, which is much higher than for other intercalation materials.

  6. Synthesis and properties of Nasicon-type materials

    Various composition of Na1+xSixZr2P3-xO12 (x from 1.6 to 2.4), Y-doped Nasicon (Na1+x+yZr2-yYySixP3-xO12, Na1+xZr2-yYySixP3-xO12-y, where x = 2, y = 0.12) and Fe-doped Nasicon (Na3Zr2/3Fe4/3P3O12) were prepared by coprecipitating. Differential thermal analysis (DTA), thermogravimetry (TG), differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and impedance spectroscopy (IS) were used as experimental techniques.In order to obtain Nasicon materials free from ZrO2 admixture, the calcination of coprecipitates must be carried out in proper thermal conditions. The results of DTA, TG and XRD measurements allowed us to propose the best calcination conditions (to obtain mainly Nasicon phases - monoclinic or rhombohedral, depending on composition). Nasicon-type materials exhibit monoclinic to rhombohedral reversible structural transition, at transition temperature depending on composition (x). The influence of dopants was also studied. The DSC measurements in the temperature range RT-300 deg. C allowed us to determine the temperatures of this structural transition in the case of Na1+xSixZr2P3-xO12, and Y-doped Nasicon. In the case of Fe-doped materials this transition was not detected.Additionally, the correlation between the composition, microstructure and electrical properties was studied

  7. Modeling Ionic Conductivity in Nasicon Structures

    Mazza, Daniele

    2001-01-01

    Considering only the structure of oxygen lattice and employing bond valence equations, the conduction geometry and the activation energy of Na+ motion in Nasicons are modeled. This is performed by calculating the valence sum m(x, y, z) for a grid of points inside the oxygen lattice, then by following with iterative procedures the pathway with lowest relative m(x, y, z) values, starting from a specified position and initial direction. After a certain trajectory the Na+ ion will reach a second position in the lattice, which will usually correspond to a known crystallographic position. Different rhombohedral and monoclinic Nasicons are examined, enabling us to verify some the ionic movement. Structural parameters governing conduction are described, based on the distortions of real structures from an idealized (archetype) Nasicon structure, in turn modeled by bond valence equations.

  8. Dipole ordering and disordering in the NASICON-like structures of Na3Sc2(PO4)3 type

    In the given article the role a M-cations in creation of conductive and dielectric properties of dipole ordered phase in substance of Na3M2(PO4)3 where M =Sc, Cr, Fe and also solid solutions of Na3Sc2(1-x)M2x(PO4)3, where M=Al, Ga, Cr, Fe, Yb, Ho, Y of NASICON-type are studied. In this substance the temperature of phase transition α→β decreases with increases of ionic radius of M-cations, as well as in solid solution of Tα→β connection back inversely proportional with ionic radius of M'-cations dopants are found. The crystal framework of this typical subject deformations, as under influence of hydrostatic pressure, so and by means of charge size of M-cations are concluded. Besides, the connection are found between the conductive and dielectric properties of these substances and sizes of M-cations. The change conductive and dielectric properties of connections with infringement regulation of initial rhombohedral crystal framework structures {[Sc2(PO4)3]3-}3∞ in result of assistant M→Sc are found. (author)

  9. Structural investigations on scandium substituted nasicons

    Neutron diffraction data were used to refine the structures of three scandium substituted nasicons: Na2ZrSc(PO4)4, R bar 3cNa2.5Zr1.8Sc0.2Si1.3P1.7O12, R bar 3c and Na2.7Zr1.8Sc0.2Si1.5P1.5O12, C 2/c. The phosphate (compound 1) exhibit oxygen disorder. The second compound exhibited a similar type of oxygen disorder but also an interstitial Na+ position. The oxygen disorder in compound 2 apparently results from the position of the interstitial Na+ whereas it is suggested that the Sc site in Na2ZrSc(PO4)3 is slightly removed from that of the Zr position, requiring a shift of phosphate groups. In contrast the monoclinic phase does not exhibit oxygen disorder and all the sodium ions reside within the cavities

  10. Low-potential sodium insertion in a NASICON-type structure through the Ti(III)/Ti(II) redox couple.

    Senguttuvan, P; Rousse, G; Arroyo y de Dompablo, M E; Vezin, Hervé; Tarascon, J-M; Palacín, M R

    2013-03-13

    We report the direct synthesis of powder Na3Ti2(PO4)3 together with its low-potential electrochemical performance and crystal structure elucidation for the reduced and oxidized phases. First-principles calculations at the density functional theory level have been performed to gain further insight into the electrochemistry of Ti(IV)/Ti(III) and Ti(III)/Ti(II) redox couples in these sodium superionic conductor (NASICON) compounds. Finally, we have validated the concept of full-titanium-based sodium ion cells through the assembly of symmetric cells involving Na3Ti2(PO4)3 as both positive and negative electrode materials operating at an average potential of 1.7 V. PMID:23421416

  11. Synthesis and structural study of a new NASICON-type solid solution: Li1-x La x/3Zr2(PO4)3

    A new complete solid solution of NASICON-type compounds between LiZr2(PO4)3 and La1/3Zr2(PO4)3 was evidenced with the general formula Li1-x La x/3Zr2(PO4)3 (0≤x≤1). These phases were synthesized by a complex polymerizable method and structurally characterized from Rietveld treatment of their X-ray and neutron powder diffraction data. This solid solution results from the substitution mechanism Li+→1/3La3++2/3□ leading to an increase of the vacancies number correlated to an increase of the La content. According to this substitution mechanism, the general formula can then be written Li1-x La x/3□2x/3Zr2(PO4)3 (0≤x≤1) in order to underline the correlation between the La content and the vacancies rate. For all the compounds, the structure is clearly related to that of the NASICON family with three crystallographic domains evidenced. For 0≤x≤0.5, all the members adopt at high temperature the typical NASICON-type structure (s.g. R3-barc), while at lower temperature, their structure distorts to a triclinic form (s.g. C 1-bar), as observed for LiZr2(PO4)3 prepared above 1100 deg. C. Moreover, in this domain, the reversible transition is clearly soft and the transition temperature strongly depends of the x value. For 0.6≤x≤0.9, the compounds crystallize in a rhombohedral cell (s.g. R3-bar), while for x=1, the phase La1/3Zr2(PO4)3 is obtained (s.g. P3-bar, Z=6, a=8.7378(2) A, c=23.2156(7) A). This paper is devoted to the structure analysis of the series Li1-x La x/3Zr2(PO4)3 (0≤x≤1), from X-ray and neutron powder thermo diffraction and transmission electron microscopy (TEM) studies. - Graphical abstract: Schematic drawing of the space group evolution at 800 deg. C in the solid solution Li1-x La x/3Zr2(PO4)3 (0≤x≤1)

  12. Synthesis and structural study of a new NASICON-type solid solution: Li 1-xLa x/3Zr 2(PO 4) 3

    Barré, M.; Crosnier-Lopez, M. P.; Le Berre, F.; Suard, E.; Fourquet, J. L.

    2007-03-01

    A new complete solid solution of NASICON-type compounds between LiZr 2(PO 4) 3 and La 1/3Zr 2(PO 4) 3 was evidenced with the general formula Li 1-xLa x/3Zr 2(PO 4) 3 (0⩽ x⩽1). These phases were synthesized by a complex polymerizable method and structurally characterized from Rietveld treatment of their X-ray and neutron powder diffraction data. This solid solution results from the substitution mechanism Li +→1/3La 3++2/3□ leading to an increase of the vacancies number correlated to an increase of the La content. According to this substitution mechanism, the general formula can then be written Li 1-xLa x/3□ 2x/3Zr 2(PO 4) 3 (0⩽ x⩽1) in order to underline the correlation between the La content and the vacancies rate. For all the compounds, the structure is clearly related to that of the NASICON family with three crystallographic domains evidenced. For 0⩽ x⩽0.5, all the members adopt at high temperature the typical NASICON-type structure (s.g. R3¯ c), while at lower temperature, their structure distorts to a triclinic form (s.g. C 1¯), as observed for LiZr 2(PO 4) 3 prepared above 1100 °C. Moreover, in this domain, the reversible transition is clearly soft and the transition temperature strongly depends of the x value. For 0.6⩽ x⩽0.9, the compounds crystallize in a rhombohedral cell (s.g. R3¯), while for x=1, the phase La 1/3Zr 2(PO 4) 3 is obtained (s.g. P3¯, Z=6, a=8.7378(2) Å, c=23.2156(7) Å). This paper is devoted to the structure analysis of the series Li 1-xLa x/3Zr 2(PO 4) 3 (0⩽ x⩽1), from X-ray and neutron powder thermo diffraction and transmission electron microscopy (TEM) studies.

  13. Synthesis and Vitrification of Nasicon Type Lithium Borophosphate Glasses

    Nithya, H.; Kawamura, Junichi; Iwai, Yoshiki; Takekawa, Reiji; Kuwata, Naoaki; Matsuda, Yasutaka

    2013-07-01

    NASICON type Li ion conducting Lithium borophosphate (Li3B2(PO4)3) and lead doped lithium borophosphate (Li3+xPbxB2-x(PO4)3 x = 0.2, 0.4, 0.6, 0.8) glass electrolyte has been prepared by melt quenching method. The effect of lead on the structure of the Lithium borophosphate glass network has been studied by Raman and 31P MAS Nuclear Magnetic resonance analysis. The behavior of the glass transition and electrical conductivity has been interpreted as a function of structural changes induced in the glass network when lead is doped in the Lithium borophosphate by means of DSC and ac impedance spectroscopic technique.

  14. Synthesis of NASICON-type lithium zirconium phosphate

    Methods of thermogravimetry and X-ray diffraction analysis are applied to study chemical transformations running in the process of synthesis of lithium-zirconium phosphate (LiZr2(PO4)3) with a NASICON structure. It is shown that on annealing of a 3Zr(HPO4)2·H2O+Li2CO3+ZrO2 composition mixture the formation of a NASICON phase begins already at 600 Deg C. However, further temperature increasing results in parallel formation of zirconium pyrophosphate and noncontrolled losses of lithium because of volatility of its compounds. A well formed high conductivity NASICON phase appears only above 1100 Deg C. It has been possible to obtain single-phase LiZr2(PO4)3 when using a two-step synthesis procedure only

  15. Synthesis of NASICON-type structured NaTi2(PO4)3-graphene nanocomposite as an anode for aqueous rechargeable Na-ion batteries

    Pang, Gang; Yuan, Changzhou; Nie, Ping; Ding, Bing; Zhu, Jiajia; Zhang, Xiaogang

    2014-05-01

    A new solvothermal strategy combined with calcination has been developed to synthesize NaTi2(PO4)3-graphene nanocomposites. X-ray diffraction, thermogravimetric analysis, field-emission scanning electron microscopy and transmission electron microscopy were performed to characterize their microstructures and morphologies. It was found that NASICON-type structured NaTi2(PO4)3 nanoparticles with highly crystallinity were homogeneously anchored on the surface of conducting graphene nanosheets, forming a two-dimensional hybrid nanoarchitecture. A possible growth mechanism was also discussed based on time-dependent experiments. When used as anode materials for Na-ion batteries, the nanocomposites exhibited excellent electrochemical performance with high-rate capability and excellent cycling stability in 1 M Na2SO4 aqueous electrolyte. The electrode delivered high specific capacities of 110, 85, 65, 40 mA h g-1 at 2, 5, 10 and 20 C, respectively, and still retained 90% of the initial capacity after 100 cycles at 2 C.A new solvothermal strategy combined with calcination has been developed to synthesize NaTi2(PO4)3-graphene nanocomposites. X-ray diffraction, thermogravimetric analysis, field-emission scanning electron microscopy and transmission electron microscopy were performed to characterize their microstructures and morphologies. It was found that NASICON-type structured NaTi2(PO4)3 nanoparticles with highly crystallinity were homogeneously anchored on the surface of conducting graphene nanosheets, forming a two-dimensional hybrid nanoarchitecture. A possible growth mechanism was also discussed based on time-dependent experiments. When used as anode materials for Na-ion batteries, the nanocomposites exhibited excellent electrochemical performance with high-rate capability and excellent cycling stability in 1 M Na2SO4 aqueous electrolyte. The electrode delivered high specific capacities of 110, 85, 65, 40 mA h g-1 at 2, 5, 10 and 20 C, respectively, and still retained 90% of the initial capacity after 100 cycles at 2 C. Electronic supplementary information (ESI) available: Synthesis of graphite oxide, TG curve of NaTi2(PO4)3-GNS, XRD patterns and morphology of GO, TiO2-GNS, Ti5P4O20-GNS, and NaTi2(PO4)3-GNS. See DOI: 10.1039/c3nr06730k

  16. Structural and Luminescent Properties of a Nasicon-Type Phosphate Cu I0.5Mn II0.25Zr 2(PO 4) 3

    Mouline, A.; Alami, M.; Brochu, R.; Olazcuaga, R.; Parent, C.; Le Flem, G.

    2000-07-01

    The phosphate CuI0.5MnII0.25Zr2(PO4)3 can be obtained at 1000°C by exchange reaction in CuII0.5Zr2(PO4)3. It crystallizes in the rhombohedral system (space group Roverline3) with the parameters ah=8.8352(1) Å and ch=22.254(5) Å in the equivalent hexagonal cell. The structure refined by the Rietveld method is typical of Nasicon-type structure. Mn2+ ions occupy partially the M1 site, while Cu+ ions are distributed over the M1 and M2 sites generated by the space group. This compound exhibits two fluorescences, occurring in the violet and orange regions and assigned respectively to isolated Cu+ and Mn2+ ions. Two other luminescences detected in the blue and green range at low temperature correspond respectively to (Cu2)+ and (Cu+)2 pairs. Efficient energy transfer Cu+→Mn2+ is observed at room temperature strengthening the orange emission of Mn2+ in the M1 site.

  17. Photocatalytic activity of glass ceramics containing Nasicon-type crystals

    Fu, Jie, E-mail: fu@ohara-inc.co.jp [R and D Department, Ohara Inc., Sagamihara-shi, Kanagawa 252-5286 (Japan)

    2013-01-15

    Graphical abstract: Display Omitted Highlights: ► Glass ceramics containing Nasicon-type crystals were prepared. ► The glass ceramics showed photocatalytic activity under UV irradiation. ► Higher activity was observed in the MgTi{sub 4}(PO{sub 4}){sub 6}- and CaTi{sub 4}(PO{sub 4}){sub 6}-containing glass ceramics. -- Abstract: Glass ceramics were prepared by heat-treating MO–TiO{sub 2}–P{sub 2}O{sub 5} (M = Mg, Ca, Sr and Ba) and R{sub 2}O–TiO{sub 2}–P{sub 2}O{sub 5}–SiO{sub 2} (R = Li, Na and K) glasses, and their photocatalytic activity was investigated. The crystalline phases precipitated in the glasses were only Nasicon-type crystals, MTi{sub 4}(PO{sub 4}){sub 6} or RTi{sub 2}(PO{sub 4}){sub 3}. Decomposition experiments of both methylene blue (MB) and acetaldehyde showed that the glass ceramics exhibited effective photocatalytic activity. The activity did not depend on the radius of the M{sup 2+} or R{sup +} ion, and higher activity was observed in the MgTi{sub 4}(PO{sub 4}){sub 6} and CaTi{sub 4}(PO{sub 4}){sub 6} precipitated glass ceramics.

  18. Photocatalytic activity of glass ceramics containing Nasicon-type crystals

    Graphical abstract: Display Omitted Highlights: ► Glass ceramics containing Nasicon-type crystals were prepared. ► The glass ceramics showed photocatalytic activity under UV irradiation. ► Higher activity was observed in the MgTi4(PO4)6- and CaTi4(PO4)6-containing glass ceramics. -- Abstract: Glass ceramics were prepared by heat-treating MO–TiO2–P2O5 (M = Mg, Ca, Sr and Ba) and R2O–TiO2–P2O5–SiO2 (R = Li, Na and K) glasses, and their photocatalytic activity was investigated. The crystalline phases precipitated in the glasses were only Nasicon-type crystals, MTi4(PO4)6 or RTi2(PO4)3. Decomposition experiments of both methylene blue (MB) and acetaldehyde showed that the glass ceramics exhibited effective photocatalytic activity. The activity did not depend on the radius of the M2+ or R+ ion, and higher activity was observed in the MgTi4(PO4)6 and CaTi4(PO4)6 precipitated glass ceramics.

  19. NASICON Open Framework Structured Transition Metal Oxides for Lithium Batteries

    Begam, K.M.; Michael, M.S.; Prabaharan, S. R. S.

    2010-01-01

    We identified a group of NASICON open framework structured polyanion materials and examined the materials for rechargeable lithium battery application. We found that the open framework structure of these materials facilitated easy insertion/extraction of lithium into/from their structure. We synthesized the materials in lithium-rich [Li2M2(MoO4)3] and lithium-free [LixM2(MoO4)3] (M= Ni, Co) phases, for the first time, by means of a low temperature soft-combustion technique. The soft-combustio...

  20. NASICON-type Na3V2(PO43

    Igor V. Zatovsky

    2010-02-01

    Full Text Available Single crystals of the title compound, trisodium divanadium(III tris(orthophosphate, were grown from a self-flux in the system Na4P2O7–NaVP2O7. Na3V2(PO43 belongs to the family of NASICON-related structures and is built up from isolated [VO6] octahedra (3. symmetry and [PO4] tetrahedra (.2 symmetry interlinked via corners to establish the framework anion [V2(PO43]3−. The two independent Na+ cations are partially occupied [site-occupancy factors = 0.805 (18 and 0.731 (7] and are located in channels with two different oxygen environments, viz sixfold coordination for the first (overline{3}. symmetry and eightfold for the second (.2 symmetry Na+ cation.

  1. RbSn2(PO4)3, a NASICON-type phosphate

    Dan Zhao; FeiFei Li; Shen Qiu; Jiali Jiao; Junran Ren

    2011-01-01

    The title compound, rubidium ditin(IV) tris(phosphate), RbSn2(PO4)3, belongs to the NASICON-type family of phosphates and crystallizes in the space group Roverline{3}. The structure is composed of PO4 tetrahedra (1 symmetry) and two slightly distorted SnO6 octahedra, both with 3. symmetry, which are interlinked through corner-sharing O atoms to form a 3∞[Sn2(PO4)3]− framework. The Rb+ cations are located on threefold inversion axes in the voids of this framework and exhibi...

  2. Caustic Recycle from Hanford Tank Waste Using Large Area NaSICON Structures (LANS)

    This report presents the results of a 5-day test of an electrochemical bench-scale apparatus using a proprietary (NAS-GY) material formulation of a (Na) Super Ion Conductor (NaSICON) membrane in a Large Area NaSICON Structures (LANS) configuration. The primary objectives of this work were to assess system performance, membrane seal integrity, and material degradation while removing Na from Group 5 and 6 tank waste from the Hanford Site

  3. Caustic Recycle from Hanford Tank Waste Using Large Area NaSICON Structures (LANS)

    Fountain, Matthew S.; Sevigny, Gary J.; Balagopal, S.; Bhavaraju, S.

    2009-03-31

    This report presents the results of a 5-day test of an electrochemical bench-scale apparatus using a proprietary (NAS-GY) material formulation of a (Na) Super Ion Conductor (NaSICON) membrane in a Large Area NaSICON Structures (LANS) configuration. The primary objectives of this work were to assess system performance, membrane seal integrity, and material degradation while removing Na from Group 5 and 6 tank waste from the Hanford Site.

  4. RbSn2(PO4)3, a NASICON-type phosphate

    Zhao, Dan; Li, FeiFei; Qiu, Shen; Jiao, Jiali; Ren, Junran

    2011-01-01

    The title compound, rubidium ditin(IV) tris­(phosphate), RbSn2(PO4)3, belongs to the NASICON-type family of phosphates and crystallizes in the space group R . The structure is composed of PO4 tetra­hedra (1 symmetry) and two slightly distorted SnO6 octa­hedra, both with 3. symmetry, which are inter­linked through corner-sharing O atoms to form a 3 ∞[Sn2(PO4)3]− framework. The Rb+ cations are located on threefold inversion axes in the voids of this framework and exhibit a coordination number of 12. The crystal studied was twinned by merohedry with a component ratio of 0.503:0.497. PMID:21754258

  5. RbSn(2)(PO(4))(3), a NASICON-type phosphate.

    Zhao, Dan; Li, Feifei; Qiu, Shen; Jiao, Jiali; Ren, Junran

    2011-05-01

    The title compound, rubidium ditin(IV) tris-(phosphate), RbSn(2)(PO(4))(3), belongs to the NASICON-type family of phosphates and crystallizes in the space group R[Formula: see text]. The structure is composed of PO(4) tetra-hedra (1 symmetry) and two slightly distorted SnO(6) octa-hedra, both with 3. symmetry, which are inter-linked through corner-sharing O atoms to form a (3) (∞)[Sn(2)(PO(4))(3)](-) framework. The Rb(+) cations are located on threefold inversion axes in the voids of this framework and exhibit a coordination number of 12. The crystal studied was twinned by merohedry with a component ratio of 0.503:0.497. PMID:21754258

  6. RbSn2(PO43, a NASICON-type phosphate

    Dan Zhao

    2011-05-01

    Full Text Available The title compound, rubidium ditin(IV tris(phosphate, RbSn2(PO43, belongs to the NASICON-type family of phosphates and crystallizes in the space group Roverline{3}. The structure is composed of PO4 tetrahedra (1 symmetry and two slightly distorted SnO6 octahedra, both with 3. symmetry, which are interlinked through corner-sharing O atoms to form a 3∞[Sn2(PO43]− framework. The Rb+ cations are located on threefold inversion axes in the voids of this framework and exhibit a coordination number of 12. The crystal studied was twinned by merohedry with a component ratio of 0.503:0.497.

  7. A systematic study of Nasicon-type Li-i + XMXTi2 _ x(PO4)(3) (M: Cr, Al, Fe) by neutron diffraction and impedance spectroscopy

    Pérez-Estébanez, Marta; Isasi-Marín, J.; Többens, D. M.; Rivera-Calzada, A.; León, C.

    2014-01-01

    Roč. 266, 15 November (2014), s. 1-8. ISSN 0167-2738 R&D Projects: GA MŠk(CZ) LO1219 Keywords : nasicon-type structure * neutron diffraction * ionic conductivity * occupation factor Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 2.561, year: 2014 http://www.sciencedirect.com/science/journal/01672738/266

  8. Local structure and redox energies of lithium phosphates with olivine- and Nasicon-like structures

    Salah, A. Ait; Jozwiak, P.; Garbarczyk, J.; Benkhouja, K.; Zaghib, K.; Gendron, F.; Julien, C. M.

    An experimental relationship between local structure and electrochemical properties is established for lithium metal phosphates LiMePO 4 (Me = Fe, Co, Mn), LiFeP 2O 7 and Li 3Fe 2(PO 4) 3 which crystallise with either the olivine-like or the Nasicon-like structure. Structural features of several lithium metal phosphates are investigated by a local probe such as the FTIR spectroscopy in order to explain the influence of either PO or PO covalent bonds on redox energies. The local cationic arrangement is also discussed with the aid of a molecular vibration model to figure out the strong covalent bonds within a PO complex for glassy Nasicon compounds.

  9. Reactions with ZrO(NO3)2 in the synthesis of solid electrolytes of the NASICON type

    The process of NASICON solid phase synthesis is studied in detail. Solid phase reactions during the synthesis of solid electrolytes of the NASICON type taking place with zirconium dinitrate-oxide end at 300-400 deg C,i.e.before the teransition of appearing zirconium dioxide into the stable monoclinic modification The presense of the nitrate group brings about the decrease in the temperature of intensive decomposition of sodium carbonate and nitrate and sodium zirconate formation close to 180 deg C

  10. Synthesis and electric conductivity of solid electrolyte of NASICON type

    The sequences of solid-phase reactions during synthesis of solid electrolyte corresponding to Na3Zr2Si2PO12 stoichiometric composition are studied. It is shown that solid-phase reaction of ZrO(NO3)2x2H2O, Na2CO3, NH4H2PO4 and amorphous SiO2 proceeds through stages of nitrate-zirconium oxide dehydration, ammonium dihydrophosphate decomposition, formation and decomposition of ammonium and sodium. Intermediate reaction products are sodium and zirconium phosphates, and some of ZrO2 takes part in the reaction in the form of amorphous or metastable tetragonal modification and another part transforms into a stable monoclinic one. NASICON formation starts at 1000 deg C, only at this stage silicon dioxide begins to react, which is already transformed from amorphous phase into a mixture of tridymite and α-crystobalyte. After annealing at 1230 deg C a single-phase solid electrolyte Na3Zr2Si2PO12 having conductivity 0.14 S/cm at 300 deg C and 0.00028 S/cm at 25 deg C

  11. Synthesis, Microstructure and Bulk Properties of Complex Nasicon-Type Ceramics

    Lipinska, Kristina; Hemmers, Oliver; Romann, Julien; Sinogeikin, Stanislav; Kalita, Patricia; Balagopal, Shekar; Nickens, Anthony

    2011-03-01

    Fast ion-conductors from the NASICON family (Na 1+x Zr 2 Si x P3 - x O12) have been the subject of extensive research due to their use in electrochemical devices such as batteries, fuel cells, thermoelectric generators and chemical sensors A fabrication challenge for these materials is to maintain long term chemical and physical stability in harsh environments We apply a multi-technique approach to show how partial substitutions with tetravalent and pentavalent cations produce NASICONs with specific morphology and modify the primary to secondary crystalline phase ratios. We use in situ synchrotron x-ray diffraction to investigate pressure-induced structural modifications and compressibility. DOE award DE-FG36-06GO86036. Use of HPCAT: DOE-BES, DOE-NNSA (CDAC), NSF, DOD-TACOM, W.M. Keck Found. Use of APS: DOE-BES, W-31-109-ENG-38.

  12. Structural and electrical properties of NASICON type solid electrolyte nanoscaled glass-ceramic powder by mechanical milling for thin film batteries.

    Patil, Vaishali; Patil, Arun; Yoon, Seok-Jin; Choi, Ji-Won

    2013-05-01

    During last two decades, lithium-based glasses have been studied extensively as electrolytes for solid-state secondary batteries. For practical use, solid electrolyte must have high ionic conductivity as well as chemical, thermal and electrochemical stability. Recent progresses have focused on glass electrolytes due to advantages over crystalline solid. Glass electrolytes are generally classified into two types oxide glass and sulfide glass. Oxide glasses do not react with electrode materials and this chemical inertness is advantageous for cycle performances of battery. In this study, major effort has been focused on the improvement of the ion conductivity of nanosized LiAlTi(PO4)3 oxide electrolyte prepared by mechanical milling (MM) method. After heating at 1000 degrees C the material shows good crystallinity and ionic conductivity with low electronic conductivity. In LiTi2(PO4)3, Ti4+ ions are partially substituted by Al3+ ions by heat-treatment of Li20-Al2O3-TiO2-P2O5 glasses at 1000 degrees C for 10 h. The conductivity of this material is 1.09 x 10(-3) S/cm at room temp. The glass-ceramics show fast ion conduction and low E(a) value. It is suggested that high conductivity, easy fabrication and low cost make this glass-ceramics promising to be used as inorganic solid electrolyte for all-solid-state Li rechargeable batteries. PMID:23858924

  13. NASICON-type Na3V2(PO4)3

    Zatovsky, Igor V.

    2010-01-01

    Single crystals of the title compound, trisodium divanadium(III) tris(orthophosphate), were grown from a self-flux in the system Na4P2O7–NaVP2O7. Na3V2(PO4)3 belongs to the family of NASICON-related structures and is built up from isolated [VO6] octahedra (3. symmetry) and [PO4] tetrahedra (.2 symmetry) interlinked via corners to establish the framework anion [V2(PO4)3]3−. The two independent Na+ cations are partially occupied [site-occupancy factors = 0.805 (18)...

  14. Infrared and Raman spectroscopic studies of glasses with NASICON-type chemistry

    K J Rao; K C Sobha; Sundeep Kumar

    2001-10-01

    Structures of NASICON glasses of the general formula AB2(PO4)3, where A = Li, Na or K and B = Fe, Ga, Ti, V or Nb, have been investigated using vibrational (IR and Raman) spectroscopies. Phosphate species appear to establish an equilibrium via a disproportionation reaction involving a dynamical bond-switching mechanism where both charge and bonds are conserved. B ions in the system acquire different coordinations to oxygens. Alkali ions cause absorptions due to cage vibrations. All the observed spectroscopic features are consistent with speciation involving disproportionation reactions.

  15. Local structure and lithium mobility in intercalated Li3Al(x)Ti(2-x)(PO4)3 NASICON type materials: a combined neutron diffraction and NMR study.

    Arbi, K; Hoelzel, M; Kuhn, A; García-Alvarado, F; Sanz, J

    2014-09-14

    The structural features of intercalated Li3AlxTi2-x(PO4)3 compounds, with x = 0 and 0.2, have been deduced by Rietveld analysis of neutron diffraction (ND) patterns recorded between 100 and 500 K. The Li insertion decreases the symmetry from R3̄c to R3̄ in analyzed compounds. In pristine Li1+xAlxTi2-x(PO4)3 samples, Li occupies mainly six-fold M1 sites at ternary axes; but in lithiated Li3AlxTi2-x(PO4)3 samples, Li is located near M2 positions at M3/M3' four-fold coordinated sites. In both cases, Li arrangement minimizes electrostatic Li-Li repulsions. The insertion of lithium resulted in the reduction of Ti(4+) to Ti(3+) that shifts (7)Li, (27)Al and (31)P MAS-NMR resonances towards more positive chemical shifts, improving the resolution of different sites. The detection of twelve components in (7)Li MAS-NMR spectra recorded at room temperature suggests the location of Li(+) ions at three-oxygen faces that define M2 cavities. From (7)Li MAS-NMR spectra, the occupancy of sites and mobility of lithium were investigated in the temperature range 100-500 K. The correlation between structural information, deduced by neutron diffraction, and lithium mobility, deduced by NMR spectroscopy, provides new insights into structural factors that affect lithium mobility in materials with NASICON structure. PMID:25070935

  16. Na4Fe2+Fe3+(PO43, a new synthetic NASICON-type phosphate

    Frédéric Hatert

    2009-04-01

    Full Text Available This paper reports the crystal structure of tetrasodium diiron tris(phosphate, Na4Fe2+Fe3+(PO43, which has been synthesized hydrothermally at 773 K and 0.1 GPa. The crystal structure has been refined in the space group Roverline{3}c and is identical to that of γ-NASICON. The heteropolyhedral framework is based on a regular alternation, in three dimensions, of corner-sharing PO4 tetrahedra and FeO6 octahedra, constituting so-called `lantern units' stacked along the c axis. The Na+ cations are distributed over two crystallographic sites: the six-coordinated Na1 site which lies between two `lantern units', and the eight-coordinated Na2 site which lies at the same z value as the P site.

  17. Na(4)FeFe(PO(4))(3), a new synthetic NASICON-type phosphate.

    Hatert, Frédéric

    2009-01-01

    This paper reports the crystal structure of tetra-sodium diiron tris(phosphate), Na(4)Fe(2+)Fe(3+)(PO(4))(3), which has been synthesized hydro-thermally at 773 K and 0.1 GPa. The crystal structure has been refined in the space group Rc and is identical to that of γ-NASICON. The heteropolyhedral framework is based on a regular alternation, in three dimensions, of corner-sharing PO(4) tetra-hedra and FeO(6) octa-hedra, constituting so-called 'lantern units' stacked along the c axis. The Na(+) cations are distributed over two crystallographic sites: the six-coordinated Na1 site which lies between two 'lantern units', and the eight-coordinated Na2 site which lies at the same z value as the P site. PMID:21582313

  18. Characterization of NASICON-type Na solid electrolyte ceramics by impedance spectroscopy

    Kazakevičius, E.; Kežionis, A.; Žukauskaitė, L.; Barré, M.; Šalkus, T.; Orliukas, A.

    2014-08-01

    Na solid electrolytes are cheaper than the ones of Li and could be of interest to apply in secondary batteries and gas sensors. In the present work, the NASICON-type Na1.3Ti1.7Al0.3(PO4)3 compound has been synthesized by Pechini method and the phase purity of the compound was confirmed by XRD. Ceramics of the compound were prepared in several different sintering temperatures and the morphology of the samples was examined by SEM. The investigation of the electrical properties was performed in 10 Hz to 3 ṡ 109 Hz and 300-500 K frequency and temperature ranges by means of impedance spectroscopy. The impedance spectra were analyzed and observed dispersions were related to microstructure of the ceramics.

  19. Electrical Properties of NASICON-type Structured Li1.3Al0.3Ti1.7(PO4)3 Solid Electrolyte Prepared by 1,2-Propylene glycol-assisted Sol-gel Method

    Zhang, Lin-chao; Chen, Peng; Hu, Zhang; Chen, Chun-hua

    2012-12-01

    Lithium-ion conductor Li1.3Al0.3Ti1.7(PO4)3 with an ultrapure NASICON-type phase is synthesized by a 1,2-propylene glycol (1,2-PG)-assisted sol-gel method and characterized by differential thermal analysis-thermo gravimetric analysis, X-ray diffraction, scanning electron microscopy, electrochemical impedance spectroscopy, and chronoamperometry test. Due to the use of 1,2-PG, a homogeneous and light yellow transparent precursor solution is obtained without the precipitation of Ti4+ and Al3+ with PO43-. Well crystallized Li1.3Al0.3Ti1.7(PO4)3 can be prepared at much lower temperatures from 850 °C to 950 °C within a shorter synthesis time compared with that prepared at a temperature above 1000 °C by a conventional solid-state reaction method. The lithium ionic conductivity of the sintered pellets is up to 0.3 mS/cm at 50 °C with an activation energy as low as 36.6 kJ/mol for the specimen pre-sintered at 700 °C and sintered at 850 °C. The high conductivity, good chemical stability and easy fabrication of the Li1.3Al0.3Ti1.7(PO4)3 provide a promising candidate as solid electrolyte for all-solid-state Li-ion rechargeable batteries.

  20. NASICON-type Na3V2(PO4)3

    Zatovsky, Igor V.

    2010-01-01

    Single crystals of the title compound, tris­odium divanadium(III) tris­(orthophosphate), were grown from a self-flux in the system Na4P2O7–NaVP2O7. Na3V2(PO4)3 belongs to the family of NASICON-related structures and is built up from isolated [VO6] octa­hedra (3. symmetry) and [PO4] tetra­hedra (.2 symmetry) inter­linked via corners to establish the framework anion [V2(PO4)3]3−. The two independent Na+ cations are partially occupied [site-occupancy factors = 0.805 (18) and 0.731 (7)] and are located in channels with two different oxygen environments, viz sixfold coordination for the first (. symmetry) and eightfold for the second (.2 symmetry) Na+ cation. PMID:21579586

  1. NASICON-type Na(3)V(2)(PO(4))(3).

    Zatovsky, Igor V

    2010-01-01

    Single crystals of the title compound, tris-odium divanadium(III) tris-(orthophosphate), were grown from a self-flux in the system Na(4)P(2)O(7)-NaVP(2)O(7). Na(3)V(2)(PO(4))(3) belongs to the family of NASICON-related structures and is built up from isolated [VO(6)] octa-hedra (3. symmetry) and [PO(4)] tetra-hedra (.2 symmetry) inter-linked via corners to establish the framework anion [V(2)(PO(4))(3)](3-). The two independent Na(+) cations are partially occupied [site-occupancy factors = 0.805 (18) and 0.731 (7)] and are located in channels with two different oxygen environments, viz sixfold coordination for the first (. symmetry) and eightfold for the second (.2 symmetry) Na(+) cation. PMID:21579586

  2. A mixed-valence niobium phosphate with an empty Nasicon structure: Nb2(PO4)3

    Niobium(IV) niobium(V) phosphate, Mr=470.73, trigonal, Ranti 3c, a=8.6974(7), c=22.123(2) A, V=1449.3(3) A3, Z=6, Dx=3.24 Mg m-3, λ(Mo Kα)=0.71073 A, μ=2.824 mm-1, T=294 K, F(000)=223, R=0.0347 and wR=0.03706 for 435 observed reflections. The niobium has a mixed valence (IV)-(V). The framework is built up from NbO6 octahedra sharing corners with PO4 tetrahedra and belongs to the empty Nasicon-type structure. (orig.)

  3. A New Nasicon-Type Phosphate Co 0.5Ti 2(PO 4) 3: I. Elaboration, Optical and Magnetic Properties

    Olazcuaga, R.; Dance, J. M.; Le Flem, G.; Derouet, J.; Beaury, L.; Porcher, P.; El Bouari, A.; El Jazouli, A.

    1999-03-01

    A new cobalt titanium monophosphate has been prepared by low temperature method. It crystallizes with the Nasicon-type structure. The indexation of the X-ray diffraction pattern is consistent with the Roverline3or the R32 space groups. The atomic arrangement is a three-dimensional framework formed by PO 4tetrahedra sharing corners with TiO 6octahedra. Co 2+is located in half of the antiprism M(1) sites in a centered ( Roverline3) or off- centered ( R32) position. The optical, EPR and magnetic data can account for a pure ionic Co-O bond.

  4. 23Na NMR Study of NASICON-type Compounds, Na1+xScxTi2-x(PO4)3

    Masui, Hirotsugu; Ueda, Takahiro; Miyakubo, Keisuke; Eguchi, Taro; Nakamura, Nobuo

    2000-02-01

    The structure of NASICON-type compounds, Na1+xScxTi2-x(PO4)3 (O ≤ x ≤ 2), and the dynamics of Na+ have been investigated by 23Na NMR spectroscopy. It was found that the 23Na 1D and 2D MQMAS spectra depend on the Na concentration, suggesting strongly that the Na+ ions are distributed between two crystallographically nonequivalent sites, one is a special position with axial symmetry, and the other a position of low symmetry. The chemical exchange between these different sites in the crystal takes place at room temperature, which may cause the high Na ion conduction of this material

  5. A carbon coated NASICON structure material embedded in porous carbon enabling superior sodium storage performance: NaTi2(PO4)3 as an example

    Jiang, Yu; Zeng, Linchao; Wang, Jiaqing; Li, Weihan; Pan, Fusen; Yu, Yan

    2015-08-01

    Sodium super ion conductor (NASICON) type structure materials (e.g. Na3V2(PO4)3, NaTi2(PO4)3) have been considered as promising electrode materials for sodium-ion batteries (NIBs). However, the inherent poor electronic conductivity of the NASICON type structure materials owing to their poor electronic conductivity of phosphates leads to poor cyclability and rate capability. Here, we develop a general strategy to achieve high rate capability and long cycle life by preparing ``double carbon coating'' NASICON NaTi2(PO4)3 using a soft-chemical method. The obtained carbon-coated NaTi2(PO4)3 within the porous carbon matrix (denoted as NTP@C@PC) imparts a reversible capability of 103 mA h g-1 at 5 C after 5000 cycles and a rate capability of 64 mA h g-1 at 50 C for sodium storage. The high capacity, stable cyclability and excellent rate capability of the NTP@C@PC are attributed to the advantages of the special structure: the fast Na+/e- transfer in the nanocomposites, large surface area and mesoporous nature of the 3D porous carbon matrix that facilitate the electrolyte to soak in, an intimate interaction between the particles and the carbon matrix. In addition, the 3D porous carbon matrix could effectively accommodate the volume variation during a repeated sodiation/desodiation process.Sodium super ion conductor (NASICON) type structure materials (e.g. Na3V2(PO4)3, NaTi2(PO4)3) have been considered as promising electrode materials for sodium-ion batteries (NIBs). However, the inherent poor electronic conductivity of the NASICON type structure materials owing to their poor electronic conductivity of phosphates leads to poor cyclability and rate capability. Here, we develop a general strategy to achieve high rate capability and long cycle life by preparing ``double carbon coating'' NASICON NaTi2(PO4)3 using a soft-chemical method. The obtained carbon-coated NaTi2(PO4)3 within the porous carbon matrix (denoted as NTP@C@PC) imparts a reversible capability of 103 mA h g-1 at 5 C after 5000 cycles and a rate capability of 64 mA h g-1 at 50 C for sodium storage. The high capacity, stable cyclability and excellent rate capability of the NTP@C@PC are attributed to the advantages of the special structure: the fast Na+/e- transfer in the nanocomposites, large surface area and mesoporous nature of the 3D porous carbon matrix that facilitate the electrolyte to soak in, an intimate interaction between the particles and the carbon matrix. In addition, the 3D porous carbon matrix could effectively accommodate the volume variation during a repeated sodiation/desodiation process. Electronic supplementary information (ESI) available. See DOI: 10.1039/C5NR03978A

  6. Na4Fe2+Fe3+(PO4)3, a new synthetic NASICON-type phosphate

    Frédéric Hatert

    2009-01-01

    This paper reports the crystal structure of tetrasodium diiron tris(phosphate), Na4Fe2+Fe3+(PO4)3, which has been synthesized hydrothermally at 773 K and 0.1 GPa. The crystal structure has been refined in the space group Roverline{3}c and is identical to that of γ-NASICON. The heteropolyhedral framework is based on a regular alternation, in three dimensions, of corner-sharing PO4 tetrahedra and FeO6 octahedra, constituting so-called `lantern units' stacked along t...

  7. Hydrothermal synthesis, structural and physico-chemical characterizations of two Nasicon phosphates: M0.50IITi2(PO4)3 (M = Mn, Co)

    The family of titanium Nasicon-phosphates of generic formula M0.5IITi2(PO4)3 has been revisited using hydrothermal techniques. Two phases have been synthesized: Mn0.5IITi2(PO4)3 (MnTiP) and Co0.5IITi2(PO4)3 (CoTiP). Single crystal diffraction studies show that they exhibit two different structural types. Mn0.5IITi2(PO4)3 phosphate crystallizes in the R-3 space group, with the cell parameters a = 8.51300(10) A and c = 21.0083(3) A (V = 1318.52(3) A3 and Z = 6). The Co0.5IITi2(PO4)3 phosphate crystallizes in the R-3c space group, with a = 8.4608(9) A and c = 21.174(2) A (V = 1312.7(2) A3 and Z = 6). These two compounds are clearly related to the parent Nasicon-type rhombohedral structure, which can be described using [Ti2(PO4)3] framework composed of two [TiO6] octahedral interlinked via three [PO4] tetrahedra. 31P magic-angle spinning nuclear magnetic resonance (MAS-NMR) data are presented as supporting data. Curie-Weiss-type behavior is observed in the magnetic susceptibility. The phases are also characterized by IR spectroscopy and UV-visible.

  8. Structure and properties of NASICON synthesized by two different zirconium salts

    Dang, Heng-yao; Guo, Xing-min; Huang, Yong-ping; Rong, Jiang-qi

    2012-08-01

    ZrOCl2·8H2O and ZrO(NO3)2·2H2O were used respectively to synthesize a NASICON solid electrolyte by a sol-gel method. The structure and properties of two samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). The crystal structure was investigated by the Rietveld refinement. It is found that both the samples contain a monoclinic C2/ c phase as the main conductive phase with the lattice parameters of a=1.56312 nm, b=0.90784 nm and c=0.92203 nm, though a small amount of rhombohedral phase is also detected in the final product. The sample synthesized by ZrO(NO3)2·2H2O contains more monoclinic phase (89.48wt%) than that synthesized by ZrOCl2·8H2O (74.91wt%). As expected, the ionic conductivity of the latter is higher than that of the former; however, the activation energy of the latter (0.37 eV) is slightly higher than that of the former (0.35 eV).

  9. Na4Fe2+Fe3+(PO4)3, a new synthetic NASICON-type phosphate

    Hatert, Frédéric

    2009-01-01

    This paper reports the crystal structure of tetra­sodium diiron tris(phosphate), Na4Fe2+Fe3+(PO4)3, which has been synthesized hydro­thermally at 773 K and 0.1 GPa. The crystal structure has been refined in the space group R c and is identical to that of γ-NASICON. The heteropolyhedral framework is based on a regular alternation, in three dimensions, of corner-sharing PO4 tetra­hedra and FeO6 octa­hedra, constituting so-called ‘lantern units’ stacked along the c axis. The Na+ cations are distributed over two crystallographic sites: the six-coordinated Na1 site which lies between two ‘lantern units’, and the eight-coordinated Na2 site which lies at the same z value as the P site. PMID:21582313

  10. Synthesis of sodium zirconate-phosphate and zirconate-silicate forming solid solutions of the NASICON type

    Synthesis of NASICON-type solid electrolytes through heating of Na2CO3, ZrO(NO3)2·2H2O and NH4H2PO4(or SiO2) ternary mixtures occurs through the stage of formation and decomposition of sodium nitrate. Formation of NaZr2P3O12 begins at 250 deg C and completes at 1000 deg C within the phosphatic system at stoichiometric proportion of the initial reagents. At the excess of sodium carbonate ZrO2 and Na2PO4 mixture is the reaction final product. Na2ZrSi3O10 is the reaction product within the silicate system at different proportions of initial components and at 1200 deg C temperature

  11. 31P and 29Si NMR investigations of the structure of NASICON-compounds

    First systematic NMR investigations of several NASICON compounds are described. In the original NASICON Na1+xZr2(SiO4)x(PO4)3-x the observed down-field shift (for increasing x) of both 31P and 29Si MAS NMR lines is explained by a change of the net atomic charge of the zirconium atoms caused by the substitution of the lattice positions of phosphorus by silicon atoms. The 'von Alpen' compound Na4ZrSi3O10 consists of two phases; the crystalline Na4Zr2(SiO4)3 and the glassy phase 2 Na2O · 3 SiO2. Moreover, it is shown that NMR can be used to investigate the statistical substitution of lattice positions of the zirconium atoms by magnesium atoms in the mixed crystals Na1+2xMgxZr2-x(PO4)3. (author)

  12. Vitrification of K3M2P3O12 (M = B, Al, Bi) NASICON-type materials and electrical relaxation studies

    Vitreous phases of K3M2P3O12 (M = B, Al, Bi) NASICON-type materials are prepared and their electrical properties are investigated over a frequency range from 42 Hz to 1 MHz and at different temperatures. An anomalous diffusion model (ADM) is applied to discuss the ac conductivity, permittivity and electric modulus of the NASICON-type glasses. The ADM is used to extract the dc conductivity and relevant physical parameters, namely, crossover length and relaxation frequency in the ion diffusion process. The dc conductivities and relaxation frequencies are thermally activated, with activation energies found to be in the range 0.70-0.82 eV. The frequency- and temperature-dependent conductivity spectra of individual glasses can be superimposed by means of the Summerfield scaling

  13. Double NASICON-type cell: ordered Nd3+ distribution in Li0.2Nd0.8/3Zr2(PO4)3.

    Barré, Maud; Crosnier-Lopez, Marie-Pierre; Le Berre, Françoise; Bohnké, Odile; Suard, Emmanuelle; Fourquet, Jean-Louis

    2008-06-21

    The NASICON compound Li(0.2)Nd(0.8/3)Zr(2)(PO(4))(3), synthesized by a sol-gel process, has been structurally characterized by TEM and powder diffraction (neutron and X-ray). It crystallizes in the space group R3[combining macron] (No. 148): at room temperature, the Nd(3+) ions present an ordered distribution in the [Zr(2)(PO(4))(3)](-) network which leads to a doubling of the classical c parameter (a = 8.7160(3) A, c = 46.105(1) A). Above 600 degrees C, Nd(3+) diffusion occurs leading at 1000 degrees C to the loss of the supercell. This reversible cationic diffusion in a preserved 3D [Zr(2)(PO(4))(3)](-) network is followed through thermal X-ray diffraction. Ionic conductivity measurements have been undertaken by impedance spectroscopy, while some results concerning the sintering of the NASICON compound are given. PMID:18521448

  14. Rare earth fluorescence in NASICON type phosphate glass, Na3TiZnP3O12

    The emission spectra of Pr3+, Eu3+ and Dy3+ doped in NASICON type phosphate glass, Na3TiZnP3O12 (NTZP) are studied. The dopant rare earth ions occupy sites with 8-9 coordination in a highly covalent environment. For Pr3+ ion, calculated and observed branching ratios for lasing transitions 3P0 → 3H4.6 agree well and found to be 0.64 and 0.24, respectively. The emissions of Pr3+ show strong temperature dependence on account of Boltzmann population of the higher excited states at room temperature. The excitation spectrum of Eu3+ gives rise to phonon assisted side band for 5D2 7F0 transition at higher energy side with a phonon energy maximum of 1022 cm-1 and an electron phonon coupling strength (g) of 0.018. The value of phonon energy maximum agrees with infrared spectral data. The results show that observation of high energy emissions in phosphate glasses require much higher g values. The red/orange and yellow/blue transitions of Eu3+ and Dy3+, respectively show that the Eu3+ occupy more distorted site than Dy3+. (author)

  15. A study on lithium/air secondary batteries - Stability of NASICON-type glass ceramics in acid solutions

    Shimonishi, Y.; Zhang, T.; Imanishi, N.; Hirano, A.; Takeda, Y.; Yamamoto, O. [Department of Chemistry, Faculty of Engineering, Mie University, 1577 Kurimamachiay-cho, Tsu, Mie 514-8507 (Japan); Johnson, P.; Sammes, N. [Department of Metallurgical and Materials Engineering, Colorado School of Mines, 1500 Illinois Street, Golden, CO 80401 (United States)

    2010-09-15

    The stability of a NASICON-type lithium ion conducting solid electrolyte, Li{sub 1+x+y}Ti{sub 2-x}Al{sub x}P{sub 3-y}Si{sub y}O{sub 12} (LTAP), in acetic acid and formic acid solutions was examined. XRD patterns of the LTAP powders immersed in 100% acetic acid and formic acid at 50 C for 4 months showed no change as compared to the pristine LTAP. However, the electrical conductivity of LTAP drastically decreased. On the other hand, no significant electrical conductivity change of LTAP immersed in lithium formate saturated formic acid-water solution was observed, and the electrical conductivity of LTAP immersed in lithium acetate saturated acetic acid-water increased. Cyclic voltammogram tests suggested that acetic acid was stable up to a high potential, but formic acid decomposed under the decomposition potential of water. The acetic acid solution was considered to be a candidate for the active material in the air electrode of lithium-air rechargeable batteries. The cell reaction was considered as 2Li + 2 CH{sub 3}COOH + 1/2O{sub 2} = 2CH{sub 3}COOLi + H{sub 2}O. The energy density of this lithium-air system is calculated to be 1477 Wh kg{sup -1} from the weights of Li and CH{sub 3}COOH, and an observed open-circuit voltage of 3.69 V. (author)

  16. Electrochemical properties of rechargeable aqueous lithium ion batteries with an olivine-type cathode and a Nasicon-type anode

    Liu, Xiao-Hong; Saito, Taishi; Doi, Takayuki; Okada, Shigeto; Yamaki, Jun-ichi [Institute of Material Chemistry and Engineering Science, Kyushu University, Kasuga Koen 6-1, Kasuga 816-8580 (Japan)

    2009-04-01

    Rechargeable aqueous lithium ion batteries have been developed by using olivine LiMn{sub 0.05}Ni{sub 0.05}Fe{sub 0.9}PO{sub 4} as cathode material, Nasicon LiTi{sub 2}(PO{sub 4}){sub 3} as anode material, and saturated Li{sub 2}SO{sub 4} solution as electrolyte. The cycling performance and rate capability of these batteries have been investigated. At a current density of 0.2 mA/cm{sup 2}, the initial discharge capacity of the battery was approximately 103.9 mAh/g, and the potential plateau was located at 0.92 V. The rate capability of aqueous electrolyte was found to be preferable to that of organic electrolyte. Such inexpensive, secure and high rate rechargeable lithium ion battery should have a potential for use in many applications. (author)

  17. Li 2NaV 2(PO 4) 3: A 3.7 V Lithium-Insertion Cathode with the Rhombohedral NASICON Structure

    Cushing, Brian L.; Goodenough, John B.

    2001-12-01

    Li2NaV2(PO4)3 has been prepared in the rhombohedral NASICON structure via ion exchange from Na3V2(PO4)3. As a lithium-insertion cathode material, Li2NaV2(PO4)3 exhibits a specific discharge capacity of 96 mAh g-1 at a current density of 0.50 mA cm-2 with a clear plateau near 3.7 V versus lithium metal. Approximately 10% of the capacity is lost through the first 50 cycles, after which the capacity appears to stabilize. During charge and discharge, the Na+ ions tend to remain immobilized in the A(1) site of the NASICON structure, suggesting a direct A(2)→A(2) lithium-transport mechanism.

  18. Crystal structure of the true Nasicon: Na/sub 3/Zr/sub 2/Si/sub 2/PO/sub 12/

    For the first time, the results of single crystal determination of the true Nasicon are given. The structure refinement yielded the following composition: Na/sub 3.09(8)/Zr/sub 2.01(1)/P/sub 0.91/Si/sub 2.09/O/sub 12/. Evidence of the total occupancy of the Zr octahedron is found, displaying that only the Si/P non-stoichiometry mechanism is present in the Nasicon crystal. For the two temperatures which have been investigated (R.T. and 623K), the structures are very close to that of the Nasicon analog: Na/sub 3/Sc/sub 2/P/sub 3/O/sub 12/. However the Si/P substitution prevents the sodium long range ordering even in the monoclinic low temperature phase and therefore the cross over to the rhombohedral symmetry only involves very small atomic displacements. For both structures, a new sodium position (mid-Na) is displayed in the conduction channel, intermediate between the usual Na(1) and Na(2) sites

  19. Phase transition in stoichiometric NASICON

    The authors discuss the microscopic mechanism of the phase transition B2/b → R3c in stoichiometric NASICON with the aid of published data on the structures of the two modifications of this compound. The low-temperature phase is treated as dipole-ordered; the dipole order is created by compensated statistical Na dipoles. It is shown that the splitting of the cation positions improves the balance of valence forces

  20. Lithium mobility in the NASICON-type compound LiTi2(PO4)3 by nuclear magnetic resonance and impedance spectroscopies

    Lithium mobility in LiTi2(PO4)3 has been followed by 7Li NMR and impedance spectroscopies. From this analysis, three stages have been distinguished. (1) Below 230 K, lithium occupies preferentially the octahedral M1 sites of the NASICON structure. (2) Between 230 and 330 K, a low correlated and thermally activated lithium motion, with Ea = 0.47 eV, is operating, as deduced from both techniques. (3) Above 330 K, the activation energy decreases and a more extended lithium ionic motion is established. As the lithium mobility increases, progressive occupation of the eight-coordinated M2 sites is deduced from NMR data. (author)

  1. Neutron Rietveld analysis of structural changes in NASICON solid solutions Nasub(1+x)Zr2Sisub(x)Psub(3-x)O12 at elevated temperatures: x = 1.6 and 2.0 at 3200C

    Neutron Rietveld analyses of the structures of NASICON solid solutions as a function of composition have been extended to 3200C for the high-conductivity compositions x = 1.6 and 2.0. The transformation from the room temperature monoclinic C2/c structure to the hexagonal R3-barc high temperature phase involves small atomic displacements, ranging from 0.385A for Na(2) down to shifts of only a few hundredths of an Angstrom for several framework ions. The Na(1) interstice remains fully occupied to the temperature presently examined. No evidence for partial occupancy of the Zr octahedron is found, a non-stoichiometry which is possible but not obligatory for NASICON. The distortions of the framework are largest at x = 2.0 as at room temperature. The radius of the windows between Na sites at 3200C remain largest at the composition with x = 2.0 for both a Na(1)-Na(2) jump and a Na(2)-Na(2) jump. The radii are significantly larger than the maximum value available among the three symmetry-independent paths in the room-temperature monoclinic structures for both types of diffusion paths. (orig.)

  2. A study into the extracted ion number for NASICON structured Na₃V₂(PO₄)₃ in sodium-ion batteries.

    Song, Weixin; Cao, Xiaoyu; Wu, Zhengping; Chen, Jun; Huangfu, Kaili; Wang, Xiaowen; Huang, Yaliang; Ji, Xiaobo

    2014-09-01

    Excellent C-rate and cycling performance with a high specific capacity of 117.6 mA h g(-1) have been achieved on NASICON-structure Na3V2(PO4)3 sodium-ion batteries. Two different Na sites, namely Na(1) and Na(2), are reported in the open three-dimensional framework, of which the ions at the Na(2) sites should be mainly responsible for the electrochemical properties. It is vitally important and interesting to find that there are two kinds of possible ion occupation of Na ions in Na3V2(PO4)3 and the investigation of ion-extraction number is firstly explored by discussing ion occupations with the help of first-principles calculations. The ion occupation of 0.75 for all Na sites is suitable for the configuration of [Na3V2(PO4)3]2, and the two-step extraction process accompanied by structure reorganization can account for the theoretical capacity of Na3V2(PO4)3. PMID:25028981

  3. Superior charge-transfer kinetics of NASICON-type Li3V2(PO4)3 cathodes by multivalent Al3+ and Cl− substitutions

    Graphical abstract: Superior kinetic properties are noted for the multivalent Al3+ and Cl− substituted NASICON type Li3V2(PO4)3 cathodes, which enables extraordinary cycling performance especially at high current rates. -- Abstract: The kinetic properties of Li insertion in NASICON-type Li3V2(PO4)3 cathodes were enhanced substantially by Al3+ and Cl− multivalent substitutions of various concentrations. Pristine and carbon coated, Al-doped Li3V2(PO4)3 were also prepared by a conventional solid-state approach under optimized conditions. Samples phase purity was investigated through X-ray diffractometry. Li insertion was studied in half-cells at 3-4.8 V vs. Li for the removal of 3 mol of Li. Carbon-coated Li3V1.98Al0.02(PO4)2.99Cl0.01 showed the highest reversible insertion of 2.71 mol of Li (178 mAh g−1) at a current density of 0.2 mA cm−2. It showed a capacity retention of over 80% after 100 cycles. Cl− substitution led to improved performance under harsh conditions of 15 C rate and high temperature (50 °C). The enhancement of Li ion kinetics was demonstrated through cyclic voltammetry in a two-electrode configuration and electrochemical impedance spectroscopy confirmed the enhanced conductivity

  4. Hydrothermal synthesis, structure and characterization of new NASICON related potassium iron (III) pyrophosphate

    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.

  5. Hydrothermal synthesis, structural and physico-chemical characterizations of two Nasicon phosphates: M{sub 0.50}{sup II}Ti{sub 2}(PO{sub 4}){sub 3} (M = Mn, Co)

    Essehli, Rachid, E-mail: essehli_rachid@yahoo.fr [Laboratory of Mineral Solid and Analytical Chemistry ' LMSAC' , Department of Chemistry, Faculty of Sciences, University Mohamed I, Po. Box 717, 60000 Oujda (Morocco); Bali, Brahim El [Laboratory of Mineral Solid and Analytical Chemistry ' LMSAC' , Department of Chemistry, Faculty of Sciences, University Mohamed I, Po. Box 717, 60000 Oujda (Morocco); Benmokhtar, S. [Laboratoire de Chimie des Materiaux Solides (LCMS) Universite HassanII-Mohammedia, Faculte des Sciences Ben M' Sik, Departement de Chimie, Casablanca (Morocco); Fejfarova, Karla; Dusek, Michal [Institute of Physics, Na Slovance 2, 182 21 Praha 8 (Czech Republic)

    2009-07-01

    The family of titanium Nasicon-phosphates of generic formula M{sub 0.5}{sup II}Ti{sub 2}(PO{sub 4}){sub 3} has been revisited using hydrothermal techniques. Two phases have been synthesized: Mn{sub 0.5}{sup II}Ti{sub 2}(PO{sub 4}){sub 3} (MnTiP) and Co{sub 0.5}{sup II}Ti{sub 2}(PO{sub 4}){sub 3} (CoTiP). Single crystal diffraction studies show that they exhibit two different structural types. Mn{sub 0.5}{sup II}Ti{sub 2}(PO{sub 4}){sub 3} phosphate crystallizes in the R-3 space group, with the cell parameters a = 8.51300(10) A and c = 21.0083(3) A (V = 1318.52(3) A{sup 3} and Z = 6). The Co{sub 0.5}{sup II}Ti{sub 2}(PO{sub 4}){sub 3} phosphate crystallizes in the R-3c space group, with a = 8.4608(9) A and c = 21.174(2) A (V = 1312.7(2) A{sup 3} and Z = 6). These two compounds are clearly related to the parent Nasicon-type rhombohedral structure, which can be described using [Ti{sub 2}(PO{sub 4}){sub 3}] framework composed of two [TiO{sub 6}] octahedral interlinked via three [PO{sub 4}] tetrahedra. {sup 31}P magic-angle spinning nuclear magnetic resonance (MAS-NMR) data are presented as supporting data. Curie-Weiss-type behavior is observed in the magnetic susceptibility. The phases are also characterized by IR spectroscopy and UV-visible.

  6. α-Na3M2(PO4)3 (M = Ti, Fe): absolute cationic ordering in NASICON-type phases.

    Kabbour, Houria; Coillot, Daniel; Colmont, Marie; Masquelier, Christian; Mentré, Olivier

    2011-08-10

    The structure of the fully ordered α-Na(3)Ti(2)(PO(4))(3) NASICON compound was elucidated using high-quality single-crystal data. The cation/vacancy distribution forms a homogeneous 3D arrangement and could represent the absolute cationic ordering available in the full Na(3)M(2)(PO(4))(3) series, as verified for M = Fe. For M = Ti, the reversible α → γ transition was observed at 85 °C, leading to the standard disordered R ̅3c γ model. Through JPDF analysis, the most probable Na(+) zigzag M(2)-M(1) diffusion scheme was directly deduced using our accurate crystallographic data. PMID:21721564

  7. An investigation of Li0.6Na2.4V2(PO4)2F3 cathode with NASICON structure in lithium-ion battery

    Feng, Qiuju; Peng, Kang; Huang, Zhenjun; Yan, Wenbin; Tang, Shi; Liu, Qingshan

    2015-04-01

    Li0.6Na2.4V2(PO4)2F3 holding a NASICON structure is synthesized via ion exchange from Na3V2(PO4)2F3. The Na+ ions at Na(2) sites and inserted Li+ ions in this NASICON structure are suggested to give a large initial specific capacity and a hybrid-ion migration during electrochemical cycling. As a lithium-inserted cathode material, Li0.6Na2.4V2(PO4)2F3 exhibits a specific capacity of 123 mAhg-1 at a current density of 0.1C with two plateaus around 3.77 and 4.19 V vs. Li+/Li. The capacity of the Li0.6Na2.4V2(PO4)2F3/Li battery can retain 104 mAhg-1 with a high coulombic efficiency of 98.6% at 0.1C after 151 cycles.

  8. Vitrification of K{sub 3}M{sub 2}P{sub 3}O{sub 12} (M = B, Al, Bi) NASICON-type materials and electrical relaxation studies

    Mariappan, C.R. [Department of Physics, School of Physical, Chemical and Applied Sciences, Pondicherry University, R.V. Nagar, Kalapet, Pondicherry 605014 (India); Govindaraj, G. [Department of Physics, School of Physical, Chemical and Applied Sciences, Pondicherry University, R.V. Nagar, Kalapet, Pondicherry 605014 (India)]. E-mail: ggraj_7@yahoo.com; Rathan, S. Vinoth [Department of Physics, School of Physical, Chemical and Applied Sciences, Pondicherry University, R.V. Nagar, Kalapet, Pondicherry 605014 (India); Prakash, G. Vijaya [School of Physics and Astronomy, University of Southampton Highfield, Southampton S017 1BJ (United Kingdom)

    2005-11-15

    Vitreous phases of K{sub 3}M{sub 2}P{sub 3}O{sub 12} (M = B, Al, Bi) NASICON-type materials are prepared and their electrical properties are investigated over a frequency range from 42 Hz to 1 MHz and at different temperatures. An anomalous diffusion model (ADM) is applied to discuss the ac conductivity, permittivity and electric modulus of the NASICON-type glasses. The ADM is used to extract the dc conductivity and relevant physical parameters, namely, crossover length and relaxation frequency in the ion diffusion process. The dc conductivities and relaxation frequencies are thermally activated, with activation energies found to be in the range 0.70-0.82 eV. The frequency- and temperature-dependent conductivity spectra of individual glasses can be superimposed by means of the Summerfield scaling.

  9. Ion conductor Na4Hf2Ge3O12 (nasicon): hydrothermal crystallization and crystal structure

    Hydrothermal crystallization of Na, Hf - germanates is investigated within NaOH-HfO2-GeO2-H2O system at T = 600 deg C. Crystal structure of Na4Hf2Ge3O12 ion conductor with hexagonal cell parameters: a = 9.202, c = 22.407 A, Z = 6, sp.gr. R3c, R = 0.051, 1303 reflections - is determined by means of X-ray structure analysis. Analysis of structure features of MT-fragmework and Na - sublattices in NanM2T3O13 compounds (n = 1-4, M = Zr, Hf, T = Ge, Si, P) is conducted

  10. Li-ion transport in all-solid-state lithium batteries with LiCoO{sub 2} using NASICON-type glass ceramic electrolytes

    Xie, J.; Imanishi, N.; Zhang, T.; Hirano, A.; Takeda, Y.; Yamamoto, O. [Department of Chemistry, Faculty of Engineering, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507 (Japan)

    2009-04-01

    LiCoO{sub 2} thin films were deposited on the NASICON-type glass ceramics, Li{sub 1+x+y}Al{sub x}Ti{sub 2-x}Si{sub y}P{sub 3-y}O{sub 12}, by radio frequency (RF) magnetron sputtering and were annealed at different temperatures. The as-deposited and the annealed LiCoO{sub 2} thin films were characterized by X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM). It was found that the films exhibited a (1 0 4) preferred orientation after annealing and Co{sub 3}O{sub 4} was observed by annealing over 500 C due to the reaction between the LiCoO{sub 2} and the glass ceramics. The effect of annealing temperature on the interfacial resistance of glass ceramics/LiCoO{sub 2} and Li-ion transport in the bulk LiCoO{sub 2} thin film was investigated by galvanostatic cycling, cyclic voltammetry (CV), potentiostatic intermittent titration technique (PITT) and electrochemical impedance spectroscopy (EIS) with the Li/PEO/glass ceramics/LiCoO{sub 2} cell. The cell performance was limited by the Li-ion diffusion resistance in Ohara/LiCoO{sub 2} interface as well as in bulk LiCoO{sub 2}. (author)

  11. Characterization of soft-combustion-derived NASICON-type Li2Co2(MoO4)3 for lithium batteries

    This work describes the synthesis of a new polyanion material, Li2Co2(MoO4)3, belonging to the NASICON family. A low-temperature soft-combustion method using glycine as a soft-combustion fuel was adopted to obtain single-phase powders of the new material at a temperature as low as 300 deg. C. Li2Co2(MoO4)3 was found to crystallize in an orthorhombic structure (space group Pmmm) with lattice parameters a = 17.584(7) A, b 10.464(4) A and c = 5.102(9) A. The electronic state of each element present in the new material was confirmed by X-ray photoelectron spectroscopic analysis. The powders were analyzed using inductively coupled plasma emission spectroscopy. The microstructural analysis revealed that the particles (5-10 μm) have a rather columnar shape. The electrochemistry redox behavior of the new material was studied, for the first time, and the material as positive electrode was found to exhibit topotactic Li+ extraction/insertion in lithium-containing test cells

  12. NASICON-Structured NaTi2(PO4)3@C Nanocomposite as the Low Operation-Voltage Anode Material for High-Performance Sodium-Ion Batteries.

    Wang, Dongxue; Liu, Qiang; Chen, Chaoji; Li, Malin; Meng, Xing; Bie, Xiaofei; Wei, Yingjin; Huang, Yunhui; Du, Fei; Wang, Chunzhong; Chen, Gang

    2016-01-27

    NASICON-type structured NaTi2(PO4)3 (NTP) has attracted wide attention as a promising anode material for sodium-ion batteries (SIBs), whereas it still suffer from poor rate capability and cycle stability due to the low electronic conductivity. Herein, the architecture, NTP nanoparticles embedded in the mesoporous carbon matrix, is designed and realized by a facile sol-gel method. Different than the commonly employed potentials of 1.5-3.0 V, the Na(+) storage performance is examined at low operation voltages between 0.01 and 3.0 V. The electrode demonstrates an improved capacity of 208 mAh g(-1), one of the highest capacities in the state-of-the-art titanium-based anode materials. Besides the high working plateau at 2.1 V, another one is observed at approximately 0.4 V for the first time due to further reduction of Ti(3+) to Ti(2+). Remarkably, the anode exhibits superior rate capability, whose capacity and corresponding capacity retention reach 56 mAh g(-1) and 68%, respectively, over 10000 cycles under the high current density of 20 C rate (4 A g(-1)). Worthy of note is that the electrode shows negligible capacity loss as the current densities increase from 50 to 100 C, which enables NTP@C nanocomposite as the prospective anode of SIBs with ultrahigh power density. PMID:26720111

  13. Ion conductivity of nasicon ceramics

    The Nasiconss,Na1+XZr2SiXP3-XO12 o , X , 3, includes some of the best solid state sodium conductors known today. Compositions in the interval 1.6 , X , 2.6 show conductivities comparable to the best β double-prime-alumina ceramics. It is well known that the ion conductivity of β-alumina is strongly dependent on the texture of the ceramic. Here a similar behavior is reported for Nasicon ceramics. Ceramics of the bulk composition Na2.94Zr1.49Si2.20P0.80O10.85 were prepared by a gel method. The final ceramics consist of Nasicon crystals with x = 2.14 and a glass phase. The grain size and texture of the ceramics were controlled by varying the thermal history of the gel based raw materials and the sintering conditions. The room temperature resistivity of the resulting ceramics varies from 3.65*103 ohm cm to 1.23*103 ohm cm. Using the temperature comparison method and estimates of the area of grain boundaries in the ceramics, the resistivity of the Nasicon phase is estimated to be 225 ohm cm at 25 degrees C. B2O3- or Al2O3-doping of the glass bearing Nasicon ceramic lower the room temperature resistivity by a factor 2 to 5. The dopants do not substitute into the Nasicon phase in substantial amounts

  14. Synthesis of Li{sub 1}+xM{sup I}II{sub x}Ti{sub 2}-x(PO{sub 4}){sub 3} with nasicon structure, using sol-gel methods. Study of the relationship microstructure electrical properties; Sintesis mediante quimica sol gel de compuestos Li{sub 1}+xM{sup I}II{sub x}Ti{sub 2}-x(PO{sub 4}){sub 3} con estructura tipo Nasicon. Estudio de la relacion microestructura-propiedades electricas

    Perez-Estebanez, M.; Rivera-Calzada, A.; Leon, C.; Santamaria, J.; Isasi-Marin, J.

    2010-07-01

    Compounds of formula Li{sub 1}+xM{sup I}II{sub x}Ti{sub 2}-x(PO{sub 4}){sub 3} with M{sup I}II = Cr, Fe and x = 0 and 0.05 have been prepared at soft temperatures using the Pechini synthesis method, based on sol-gel chemistry. The structural and microstructural characterization by X-ray diffraction and Scanning Electron Microscopy (SEM), shows that all of them crystallize in a NASICON-type structure with similar lattice parameters. Doping with Fe and Cr, causes an increase of the density of the samples after sinterization what clearly improves the ionic conductivity of the original material, LiTi{sub 2}(PO{sub 4}){sub 3} until values of 9x10{sup -}4 S cm{sup -}1 at room temperature in the chromium-doped material. (Author)

  15. Synthesis and crystal structure of NZP-type thorium-zirconium phosphate.

    Orlova, Albina I; Volgutov, Valeriy Yu; Castro, Germán R; García-Granda, Santiago; Khainakov, Sergei A; García, José R

    2009-10-01

    Microcrystals of Th(1/4)Zr(2)(PO(4))(3) were synthesized by thermal treatment (900 degrees C) of the material obtained using sol-gel technology (including organic complex formation and etherification). Their structure [hexagonal, P3c, a = b = 8.7311(4) A, c = 23.309(2) A] includes the three-dimensional [Zr(2)(PO(4))(3)](-) NASICON-type network and extraframework 6-fold-coordinated thorium(IV) cations. PMID:19739666

  16. Phase Transition and Spin Dynamics of the NASICON-Type Na3V2(PO4)3 with the Strongly Coupled Planes of S = 1 Pseudo-Honeycomb Lattice

    Onoda, Masashige; Kanazawa, Hiroki

    2016-04-01

    The magnetic properties and spin dynamics of the NASICON-type Na3V2(PO4)3 with the strongly coupled planes of S = 1 pseudo-honeycomb lattice via the V-O-P-O-V superexchange pathways are explored through measurements of x-ray diffraction, magnetization, and nuclear magnetic resonance. Na3V2(PO4)3 and the newly synthesized Ag3V2(PO4)3 exhibit the broad maximum of magnetic susceptibility at Tm = 9 K, which is approximately understood by the coupled S = 1 dimers connecting the honeycomb lattice planes, and they undergo the antiferromagnetic transition at around TN = 4 K. The spin-lattice relaxation rate for Na ions shows the critical slowing down of spin fluctuations above TN, while at lower temperatures, it indicates the existence of an energy gap in the magnetic excitation, which may be attributed to the uniaxial magnetic anisotropy.

  17. Dielectric spectroscopy studies of NASICON materials

    Jha, Paramjyot Kumar; Pandey, O. P.; Singh, K.

    2013-06-01

    All samples of NASICON have been synthesized by taking new chemical (Na2.H.PO4.2H2O) by solid sate reaction method at different sintering temperature range (1150-1250 °C). The synthesized samples were characterized by X-ray powder diffraction and Impedance spectroscopy. The variation of (ɛ') with frequency indicates the relaxation in all the samples. A high degree of dispersion with temperature at low frequency was observed which indicates that hopping type conduction mechanism is occurring in all samples. As the frequency and temperature increased the imaginary part of impedance decreased indicating that with increase in temperature and frequency the conduction is increasing. The sample sintered at 1200 °C showed best result than other sintered samples at 1150 °C and 1250 °C respectively.

  18. Non-polarisable dry electrode based on NASICON ceramic.

    Gondran, C; Siebert, E; Fabry, P; Novakov, E; Gumery, P Y

    1995-05-01

    A NASICON-type ceramic (high sodium ion conductor) is proposed to record bioelectric signals. The electrode does not need gel before its application. The principle of the measurements is based on a sodium ion exchange between the skin and the material. Electrical measurements performed in saline solutions show that the electrode is slightly polarisable. The skin-electrode impedance was investigated. The impedance decreases as a function of the time of application. The resistive component is the major source of the impedance change. This can be explained by the perspiration process which occurs immediately with time after the application of the NASICON-based electrode on the skin. The skin condition is also an important parameter. NaCl saline solution or abrasion causes the resistance to decrease markedly. PMID:7666693

  19. Phase transitions and ionic mobility in hydrogen zirconium phosphates with the NASICON structure, H1±XZr2-XMX(PO4)3.H2O, M = Nb, Y

    Phase transitions and the mobility of proton-containing groups in hydrogen zirconium phosphate HZr2(PO4)3.nH2O with the NASICON structure were studied by X-ray powder diffraction, 1H, 31P NMR, IR spectroscopy and TG analysis. Heating HZr2(PO4)3.H2O above 420 K results in dehydration and in a rhombohedral-triclinic phase transition. Continued heating to about 490 K results in the thermal activation of cation disordering and phase transition of HZr2(PO4)3 from triclinic to rhombohedral phase. Parameter 'a' of HZr2(PO4)3 lattice decreases during the heating. It is shown that oxonium ions in HZr2(PO4)3.H2O are characterized by high rotation and translation mobility. Rotation mobility of oxonium ions can be increased by the substitution of zirconium by yttrium or niobium

  20. NASICON-related Na3.4Mn0.4Fe1.6(PO4)3

    Nikolay S. Slobodyanik; Ogorodnyk, Ivan V.; Baumer, Vyacheslav N.; Nataliya Yu. Strutynska; Michael M. Yatskin

    2012-01-01

    The solid solution, sodium [iron(III)/manganese(II)] tris­(orthophosphate), Na3.4Mn0.4Fe1.6(PO4)3, was obtained using a flux method. Its crystal structure is related to that of NASICON-type compounds. The [(Mn/Fe)2(PO4)3] framework is built up from an (Mn/Fe)O6 octa­hedron (site symmetry 3.), with a mixed Mn/Fe occupancy, and a PO4 tetra­hedron (site symmetry .2). The Na+ cations are distributed over two partially occupied sites in the cavities of the framework. One Na+ cation (site symmetry ...

  1. NASICON-related Na₃.₄Mn₀.₄Fe₁.₆(PO₄)₃.

    Yatskin, Michael M; Strutynska, Nataliya Yu; Baumer, Vyacheslav N; Ogorodnyk, Ivan V; Slobodyanik, Nikolay S

    2012-07-01

    The solid solution, sodium [iron(III)/manganese(II)] tris-(orthophosphate), Na₃.₄Mn₀.₄Fe₁.₆(PO₄)₃, was obtained using a flux method. Its crystal structure is related to that of NASICON-type compounds. The [(Mn/Fe)₂(PO₄)₃] framework is built up from an (Mn/Fe)O₆octa-hedron (site symmetry 3.), with a mixed Mn/Fe occupancy, and a PO₄ tetra-hedron (site symmetry .2). The Na⁺ cations are distributed over two partially occupied sites in the cavities of the framework. One Na⁺ cation (site symmetry -3.) is surrounded by six O atoms, whereas the other Na⁺ cation (site symmetry .2) is surrounded by eight O atoms. PMID:22807697

  2. Equilibrium relations in the system TiO2/V2O5/P2O5 and crystal structure of a NASICON-related vanadyl(V) titanium(IV) phosphate

    Titlbach, Sven; Hoffbauer, Wilfried; Glaum, Robert

    2012-12-01

    Vanadyl(V)-titanium-orthophosphate (VVO)TiIV6(PO4)9 is formed by solid state reactions in the temperature range 525≤ϑ≤780 °C. At higher temperature decomposition into V2O5 and the hitherto unknown solid solution Ti(P1-xVx)2O7 (0≤x≤0.23; 0.30≤x≤0.43) is observed. The process of phase formation has been monitored by MAS-NMR (31P, 51V) spectroscopy. Equilibrium phase relations in the quaternary system TiO2/VO2.5/PO2.5 have been determined. A structure analysis from X-ray single-crystal data (P63/m (No. 176), Z=2; a=8.4438(3) Å, c=22.215(1) Å, 14 independent atoms, 87 variables, 2066 unique reflections, R1=0.032, wR2=0.084) shows the relationship of (VVO)TiIV6(PO4)9 to the NASICON structure family. In marked contrast to the other members of this family [TiIV2O9] double-octahedra and strongly distorted tetrahedral [(VV=O)O3] groups are observed besides isolated [TiIVO6] octahedra and phosphate tetrahedra. The structure model is in agreement with the results from MAS-NMR (31P, 51V) spectroscopy.

  3. Synthesis, structure and characterisation of Fe 0.50Ti 2(PO 4) 3: A new material with Nasicon-like structure

    Benmokhtar, S.; El Jazouli, A.; Aatiq, A.; Chaminade, J. P.; Gravereau, P.; Wattiaux, A.; Fournès, L.; Grenier, J. C.

    2007-07-01

    A new iron titanyl phosphate Fe 0.50Ti 2(PO 4) 3 was synthesized by both solid-state reaction and Cu 2+-Fe 2+ ion exchange method. The material was then characterized by X-ray diffraction, Mössbauer, magnetic susceptibility measurements and optical absorption. The crystal structure of the compound was refined, using X-ray powder diffraction data, by the Rietveld profile method; it crystallizes in the rhombohedral system, space group R3¯, with a=8.511(1) Å and c=20.985(3) Å, V=1316.45(3) Å 3 and Z=6. The structure, which is compared to that of Mn 0.50Ti 2(PO 4) 3 is built up from [TiO 6] octahedra and [PO 4] tetrahedra which are linked by corner sharing along the c-axis. Fe 2+ cations are located in half of the antiprism MI sites and are orderly distributed with vacancies within the two possible positions of the MI sites of R3¯. These results were supported by the Mössbauer studies that showed the presence of one Fe 2+ site in the high spin state ( t2g4eg2). The Curie-Weiss-type behavior is observed in the magnetic susceptibility. Diffuse reflectance spectrum indicates the presence of octahedrally coordinated Fe 2+ ions.

  4. Synthesis, structure and characterisation of Fe0.50Ti2(PO4)3: A new material with Nasicon-like structure

    A new iron titanyl phosphate Fe0.50Ti2(PO4)3 was synthesized by both solid-state reaction and Cu2+-Fe2+ ion exchange method. The material was then characterized by X-ray diffraction, Mossbauer, magnetic susceptibility measurements and optical absorption. The crystal structure of the compound was refined, using X-ray powder diffraction data, by the Rietveld profile method; it crystallizes in the rhombohedral system, space group R3-bar, with a=8.511(1)A and c=20.985(3)A, V=1316.45(3)A3 and Z=6. The structure, which is compared to that of Mn0.50Ti2(PO4)3 is built up from [TiO6] octahedra and [PO4] tetrahedra which are linked by corner sharing along the c-axis. Fe2+ cations are located in half of the antiprism MI sites and are orderly distributed with vacancies within the two possible positions of the MI sites of R3-bar. These results were supported by the Mossbauer studies that showed the presence of one Fe2+ site in the high spin state (t2g4eg2). The Curie-Weiss-type behavior is observed in the magnetic susceptibility. Diffuse reflectance spectrum indicates the presence of octahedrally coordinated Fe2+ ions

  5. Electrochemical performance of all-solid-state Li batteries based LiMn{sub 0.5}Ni{sub 0.5}O{sub 2} cathode and NASICON-type electrolyte

    Xie, J.; Zhao, X.B.; Cao, G.S. [Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Imanishi, N.; Zhang, T.; Hirano, A.; Takeda, Y.; Yamamoto, O. [Department of Chemistry, Faculty of Engineering, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507 (Japan)

    2010-12-15

    LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} thin films have been deposited on the NASICON-type glass ceramics, Li{sub 1+x+y}Al{sub x}Ti{sub 2-x}Si{sub y}P{sub 3-y}O{sub 12} (LATSP), by radio frequency (RF) magnetron sputtering followed by annealing. The films have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy. All-solid-state Li/PEO{sub 18}-Li(CF{sub 3}SO{sub 2}){sub 2}N/LATSP/LiNi{sub 0.5}Mn{sub 0.5}O{sub 2}/Au cells are fabricated using the LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} thin films and the LATSP electrolyte. The electrochemical performance of the cells is investigated by galvanostatic cycling, cyclic voltammetry (CV), potentiostatic intermittent titration technique (PITT) and electrochemical impedance spectroscopy (EIS). Interfacial reactions between LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} and LATSP occur at a temperature as low as 300 C with the formation of Mn{sub 3}O{sub 4}, resulting in an increased obstacle for Li-ion diffusion across the LiNi{sub 0.5}Mn{sub 0.5}O{sub 2}/LATSP interface. The electrochemical performance of the cells is limited by the interfacial resistance between LATSP and LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} as well as the Li-ion diffusion kinetics in LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} bulk. (author)

  6. A New Nasicon-Type Phosphate:Co 0.5Ti 2(PO 4) 3II. Simulation of Optical and Magnetic Properties

    Derouet, J.; Beaury, L.; Porcher, P.; Olazcuaga, R.; Dance, J. M.; Le Flem, G.; El Bouari, A.; El Jazouli, A.

    1999-03-01

    The optical (energy level scheme) and magnetic properties (paramagnetic susceptibility as a function of the temperature and gvalues) of the polycrystalline Co 0.5Ti 2(PO 4) 3were simultaneously reproduced by use of a crystal field theory involving a set of Fk, ζ, free ion, and Bkqcrystal field parameters. The crystal field parameters calculated from the structure are in fair agreement with the experimental ones and permit us to assign R32 as the space group of the crystal structure.

  7. FT-IR and FT-Raman study of Nasicon type phosphates, ASnFe(PO 4) 3 [A = Na 2, Ca, Cd

    Antony, C. J.; Aatiq, A.; Panicker, C. Yohannan; Bushiri, M. Junaid; Varghese, Hema Tresa; Manojkumar, T. K.

    2011-01-01

    FT-Raman and FT-IR spectra of ASnFe(PO 4) 3 [A = Na 2, Ca, Cd] were recorded and analyzed. The bands were assigned in terms of the vibrational group frequencies of SnO 6 octahedral and PO 4 tetrahedral. The spectral analysis shows that the symmetry of corner shared octahedral (SnO 6) and the tetrahedral (PO 4) are lowered from their free ion symmetry state. The presence of Fe 3+ ions disrupts the S-N-O-S-N chain in the structure. This causes distortion of SnO 6 and PO 4 in the structure of all the compounds. Also it is seen that there are two distinct PO 4 tetrahedra of different P-O bond lengths. One of these tetrahedra is linearly distorted in all the title compounds. The PO 4 frequencies and bond lengths are calculated theoretically and are in agreement with the experimental values. The presence of PO 4 polyanion in the structure can reduce the redox energy and hence reduce the metal oxygen covalency strength in the structure.

  8. Li mobility in Nasicon-type materials LiM2(PO4)3, M = Ge, Ti, Sn, Zr and Hf, followed by 7Li NMR spectroscopy.

    Arbi, K; París, M A; Sanz, J

    2011-10-21

    Lithium mobility in LiM(2)(PO(4))(3) compounds, M = Ge and Sn, has been investigated by (7)Li Nuclear Magnetic Resonance (NMR) spectroscopy, and deduced information compared with that reported previously in Ti, Zr and Hf members of the series in the temperature range 100-500 K. From the analysis of (7)Li NMR quadrupole interactions (C(Q) and η parameters), spin-spin T(2)(-1) and spin-lattice T(1)(-1) relaxation rates, structural sites occupancy and mobility of lithium have been deduced. Below 250 K, Li ions are preferentially located at M(1) sites in rhombohedral phases, but occupy intermediate M(12) sites between M(1) and M(2) sites in triclinic ones. In high-temperature rhombohedral phases, a superionic state is achieved when residence times at M(1) and M(12) sites become similar and correlation effects on Li motion decrease. This state can be obtained by large order-disorder transformations in rhombohedral phases or by sharp first order transitions in triclinic ones. The presence of two relaxation mechanisms in T(1)(-1) plots of rhombohedral phases has been associated with departures of conductivity from the Arrhenius behavior. Long term mobility of lithium is discussed in terms of the cation vacancy distribution along conduction paths. PMID:21897945

  9. Nuclear quadrupole interaction measurements on 181Ta in NASICON

    The quadrupole interaction experienced by the 181Ta nucleus placed in substitution for Zr in the Na3Zr2Si2PO12 compound (NASICON) has been determined from gamma-ray angular correlation experiments in the temperature range 20-7000C. The asymmetry of the electric field-gradient tensor vanishes for T >approx. 2000C, which is an indication for a non-random substitution of Si4+ for P5+ ions and a high mobility of both Na(1) and Na(2) species in the rhombohedral structure. Furthermore, the results are consistent with the idea that the transition from a monoclinic to a rhombohedral structure is accompanied by a transfer of sodium ions from static interstitial positions into partially occupied Na(1) and/or Na(2) positions. (Auth.)

  10. NASICON-related Na3.4Mn0.4Fe1.6(PO43

    Nikolay S. Slobodyanik

    2012-07-01

    Full Text Available The solid solution, sodium [iron(III/manganese(II] tris(orthophosphate, Na3.4Mn0.4Fe1.6(PO43, was obtained using a flux method. Its crystal structure is related to that of NASICON-type compounds. The [(Mn/Fe2(PO43] framework is built up from an (Mn/FeO6 octahedron (site symmetry 3., with a mixed Mn/Fe occupancy, and a PO4 tetrahedron (site symmetry .2. The Na+ cations are distributed over two partially occupied sites in the cavities of the framework. One Na+ cation (site symmetry -3. is surrounded by six O atoms, whereas the other Na+ cation (site symmetry .2 is surrounded by eight O atoms.

  11. NASICON-related Na3.4Mn0.4Fe1.6(PO4)3

    Yatskin, Michael M.; Strutynska, Nataliya Yu.; Baumer, Vyacheslav N.; Ogorodnyk, Ivan V.; Slobodyanik, Nikolay S.

    2012-01-01

    The solid solution, sodium [iron(III)/manganese(II)] tris­(orthophosphate), Na3.4Mn0.4Fe1.6(PO4)3, was obtained using a flux method. Its crystal structure is related to that of NASICON-type compounds. The [(Mn/Fe)2(PO4)3] framework is built up from an (Mn/Fe)O6 octa­hedron (site symmetry 3.), with a mixed Mn/Fe occupancy, and a PO4 tetra­hedron (site symmetry .2). The Na+ cations are distributed over two partially occupied sites in the cavities of the framework. One Na+ cation (site symmetry -3.) is surrounded by six O atoms, whereas the other Na+ cation (site symmetry .2) is surrounded by eight O atoms. PMID:22807697

  12. Synthesis and properties of nasicon prepared from different zirconia-based precursors

    Fuentes, R. O.

    1999-12-01

    Full Text Available This work reports on the synthesis and characterization of NASICON prepared from SiO2, Na3PO4.12H2O and two types of zirconia: pure monoclinic ZrO2 and TZP (Tetragonal Polycrystalline Zirconia, with 3 mol% Y2O3 as raw materials. The classical ceramic method was used in all cases. SEM, XRD and DTA were used to follow the synthesis and sintering process, and impedance spectroscopy (IS was used to study the electrical properties of sintered pellets. Results obtained with different NASICON samples showed a significant role of composition and processing conditions on the electrical properties. Samples based on TZP, sintered at 1210ºC, exhibited densities of about 3.20 g/cm3 (98% of theoretical density of NASICON and ionic conductivities of about 2x10-3 S.cm-1 at room temperature a rather interesting result when compared with data obtained with the material prepared from pure ZrO2.

    Este trabajo trata de la síntesis y caracterización de NASICON preparado a partir de SiO2 , Na3PO4.12H2O y dos tipos de circonia, ZrO2 monoclínica pura y TZP (circonia policristalina tetragonal, con 3 moles% Y2O3 como materia prima. Se emplea el método cerámico clásico en todos los casos. Las técnicas de MEB, DRX y ATD se emplean para seguir la síntesis y el proceso de sinterización. La espectroscopia de impedancia compleja se emplea para estudiar las propiedades eléctricas de las muestras sinterizadas. Los resultados obtenidos con diferentes muestras de NASICON mostraron un papel significativo de la composición y condiciones de procesamiento sobre las propiedades eléctricas. Las muestras basadas en TZP, sinterizadas a 1210ºC, presentan densidades alrededor de 3.20 g/cm3 (98% de la densidad teórica del NASICON y conductividad iónica de 2x 10-3 5.cm-1 a temperatura ambiente, un resultado bastante interesante cuando se compara con datos obtenidos con material preparado de ZrO2 pura.

  13. Electron-irradiation induced phase transformation in La 1/3Zr 2(PO 4) 3: La 3+ displacement in a preserved NASICON framework

    Crosnier-Lopez, M. P.; Barre, M.; Le Berre, F.; Fourquet, J. L.

    2006-08-01

    The La 1/3Zr 2(PO 4) 3 NASICON-type compound (S.G. P3¯ - neutron and X-ray diffraction experiments) is investigated by transmission electron microscopy (TEM) technique, selected area electron diffraction (SAED) and high-resolution electron microscopy (HREM), in order to study locally the lanthanum distribution. An irreversible structural transformation (P - - - → P - c - → R - - -) is observed, without modification of the atomic content and cell size, as soon as the phase is illuminated by the electron beam. The progressive disappearance of the spots which do not check the R conditions on the SAED patterns is clearly shown along two zone axis, [001] and [100]. This transformation implies the displacement of the two La 3+ cations in a preserved classical [Zr 2(PO 4) 3] - network. This interesting behavior is in good agreement with the La 3+ ionic conductivity observed in La 1/3Zr 2(PO 4) 3 (4.09×10 -7 S cm -1 at 700 °C). To our knowledge, this is the first time that a complete TEM study is done on a NASICON-type phase.

  14. An amorphous LiCo{sub 1/3}Mn{sub 1/3}Ni{sub 1/3}O{sub 2} thin film deposited on NASICON-type electrolyte for all-solid-state Li-ion batteries

    Xie, J. [Department of Chemistry, Faculty of Engineering, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507 (Japan); Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Imanishi, N.; Zhang, T.; Hirano, A.; Takeda, Y.; Yamamoto, O. [Department of Chemistry, Faculty of Engineering, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507 (Japan)

    2010-09-01

    Amorphous LiCo{sub 1/3}Mn{sub 1/3}Ni{sub 1/3}O{sub 2} thin films were deposited on the NASICON-type Li-ion conducting glass ceramics, Li{sub 1+x+y}Al{sub x}Ti{sub 2-x}Si{sub y}P{sub 3-y}O{sub 12} (LATSP), by radio frequency (RF) magnetron sputtering below 130 C. The amorphous films were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The Li/PEO{sub 18}-Li(CF{sub 3}SO{sub 2}){sub 2}N/LATSP/LiCo{sub 1/3}Mn{sub 1/3}Ni{sub 1/3}O{sub 2}/Au all-solid-state cells were fabricated to investigate the electrochemical performance of the amorphous films. It was found that the low-temperature deposited amorphous cathode film shows a high discharge voltage and a high discharge capacity of around 130 mAh g{sup -1}. (author)

  15. Preparation of LiMn{sub 2}O{sub 4} thin-film electrode on Li{sub 1+x}Al{sub x}Ti{sub 2-x}(PO{sub 4}){sub 3} NASICON-type solid electrolyte

    Dokko, Kaoru; Kanamura, Kiyoshi [Department of Applied Chemistry, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachioji, Tokyo 192-0397 (Japan); CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Hoshina, Keigo; Nakano, Hiroyuki [Department of Applied Chemistry, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachioji, Tokyo 192-0397 (Japan)

    2007-12-06

    An interface consisting of LiMn{sub 2}O{sub 4} thin-film (1 {mu}m thick) electrode and Li{sub 1+x}Al{sub x}Ti{sub 2-x}(PO{sub 4}){sub 3}-based NASICON-type solid electrolyte (LTP) was prepared by a sol-gel coating method. The submicron-sized pores were involved in the thin film, and the porosity of the film was relatively high. The prepared solid-solid electrochemical interface was evaluated by cyclic voltammetry and galvanostatic charge-discharge test. Two reversible redox peaks were observed at 4.0 and 4.1 V versus Li/Li{sup +} in the cyclic voltammogram due to the redox of Mn{sup 3+/4+}. The LiMn{sub 2}O{sub 4} thin-film electrode on LTP exhibited a discharge capacity of 80 mA h g{sup -1} at 0.1 C rate. (author)

  16. Equilibrium relations in the system TiO{sub 2}/V{sub 2}O{sub 5}/P{sub 2}O{sub 5} and crystal structure of a NASICON-related vanadyl(V) titanium(IV) phosphate

    Titlbach, Sven; Hoffbauer, Wilfried [Institut fuer Anorganische Chemie der Universitaet Bonn, Gerhard-Domagk-Str. 1, D-53121 Bonn (Germany); Glaum, Robert, E-mail: rglaum@uni-bonn.de [Institut fuer Anorganische Chemie der Universitaet Bonn, Gerhard-Domagk-Str. 1, D-53121 Bonn (Germany)

    2012-12-15

    Vanadyl(V)-titanium-orthophosphate (V{sup V}O)Ti{sup IV}{sub 6}(PO{sub 4}){sub 9} is formed by solid state reactions in the temperature range 525{<=}{theta}{<=}780 Degree-Sign C. At higher temperature decomposition into V{sub 2}O{sub 5} and the hitherto unknown solid solution Ti(P{sub 1-x}V{sub x}){sub 2}O{sub 7} (0{<=}x{<=}0.23; 0.30{<=}x{<=}0.43) is observed. The process of phase formation has been monitored by MAS-NMR ({sup 31}P, {sup 51}V) spectroscopy. Equilibrium phase relations in the quaternary system TiO{sub 2}/VO{sub 2.5}/PO{sub 2.5} have been determined. A structure analysis from X-ray single-crystal data (P6{sub 3}/m (No. 176), Z=2; a=8.4438(3) A, c=22.215(1) A, 14 independent atoms, 87 variables, 2066 unique reflections, R1=0.032, wR2=0.084) shows the relationship of (V{sup V}O)Ti{sup IV}{sub 6}(PO{sub 4}){sub 9} to the NASICON structure family. In marked contrast to the other members of this family [Ti{sup IV}{sub 2}O{sub 9}] double-octahedra and strongly distorted tetrahedral [(V{sup V}=O)O{sub 3}] groups are observed besides isolated [Ti{sup IV}O{sub 6}] octahedra and phosphate tetrahedra. The structure model is in agreement with the results from MAS-NMR ({sup 31}P, {sup 51}V) spectroscopy. - Graphical abstract: (V{sup V}O)Ti{sup IV}{sub 6}(PO{sub 4}){sub 9} belongs to the NASICON structure family. Its structure contains [Ti{sup IV}{sub 2}O{sub 9}] double-octahedra and unprecedented, strongly distorted tetrahedral [(V{sup V}=O)O{sub 3}] groups, in stark contrast to other members of this family. The structure model is in agreement with the results from MAS-NMR ({sup 31}P, {sup 51}V) spectroscopy. Highlights: Black-Right-Pointing-Pointer Equilibrium relations for the subsolidus have been established for the system TiO{sub 2}/V{sub 2}O{sub 5}/P{sub 2}O{sub 5}. Black-Right-Pointing-Pointer Phase formation has been monitored by XRPD as well as by {sup 31}P- and {sup 51}-MAS-NMR. Black-Right-Pointing-Pointer A solid solution Ti(P{sub 1-x}V{sub x}){sub 2}O{sub 7} exists up to x=0.43 with a miscibility gap at 0.23{<=}x{<=}0.30. Black-Right-Pointing-Pointer The crystal structure of the new NASICON-related phosphate (V{sup V}O)Ti{sup IV}{sub 6}(PO{sub 4}){sub 9} is reported. Black-Right-Pointing-Pointer The crystal structure contains the unprecedented [(V=O)O{sub 3}] group.

  17. Part 222: sodium conductivity enhancement along domain and grain boundaries nasicon solid electrolytes

    Bulk, grain, and domain boundary sodium ion conductivity data are presented for nasicon single crystals and ceramics of composition Na/sub 1+x+4y/Zr/sub 2-y/Si/sub x/P/sub 3-x/O12 (x=0-3, y=0-0.2). For silicate-rich compositions the ''crystals'' are built out of domains and the conductance of the resulting domain bundaries are shown to determine the macroscopically observed conductivity. Grain boundaries in ceramics behave in a similar way. A structural explanation of the observed phenomena is suggested

  18. Influence of thermal cycling on properties of NASICON

    The influence of thermal cycling on the bulk and grain boundary conductivities and on microhardness of Na3Zr2Si2PO12 (NASICON) has been investigated. The electrical conductivity of calcined and sintered specimens was measured in the temperature range 293 to 673 K before and after approximately 300 cycles between 373 and 473 K. The grain conductivity was found to be much higher after thermal cycling. The microhardness of the sample drapped from 580 to 320 kp/mm2

  19. Nomenclature of inorganic structure types

    Different degrees of similarity between inorganic crystal structures are defined concisely and examples are presented that illustrate their practical application. A notation giving the coordination of atoms is presented together with some basic rules for developing crystal-chemical formulae and the Bauverband description of inorganic structure types. Typical examples of the nomenclature are: pyrite Fe[6o]{g}[S2[3;1)t

  20. Reactivity of NASICON with water and interpretation of the detection limit of a NASICON based Na(+) ion selective electrode.

    Mauvy, F; Siebert, E; Fabry, P

    1999-02-01

    The leaching of Na(+) ions from NASICON of composition Na(3)Zr(2)Si(2)PO(12) to the aqueous solution was evidenced. The origin of the Na(+) leaching was studied using Na(+) concentration and pH measurements as well as solution and X-ray analyses. The Na(+) released was mainly attributed to the dissolution of a second phase, predominantly amorphous. The rate of Na(+) release was found to be dependent on the inverse of the square of the particle size. It is proposed that it is controlled by diffusion within the particle. An effective diffusion coefficient was deduced to be of the order of 5x10(-10) cm(2) s(-1). The nature of the detection limit of the NASICON based Na(+) ion selective electrodes is discussed. PMID:18967467

  1. Influence of Si/P ordering on Na+ transport in NASICONs.

    Roy, Supriya; Kumar, P Padma

    2013-04-14

    The influence of Si/P ordering on Na(+) transport in the high conducting NASICON composition, Na3Zr2Si2PO12, is investigated using molecular dynamics simulation. The study demonstrates that the Na(+) conductivity in the system changes by more than an order of magnitude depending on the Si/P order in the structure. This rather surprising observation is attributed to the modulations in the electrostatic potential energy landscape along the conduction channel originating out of the increased coulombic repulsion of Na(+) with P(5+) ions compared to Si(4+). The study reveals the significance of the order of framework cations in fast ion transport in solids with aliovalent substitutions. PMID:23443462

  2. Restrictions to obtain NASICON by a ceramic route

    Fuentes, R. O.

    2004-08-01

    Full Text Available Highly reactive monoclinic ZrO2 powders were mixed with Na3PO4•12H2O and amorphous SiO2 in the stoichiometric quantities to obtain Na3Zr2Si2PO12. The mixtures were calcined at different temperatures (Tcalc and for variable periods of time (tcalc. Their morphology was analysed by SEM and the composition by powder XRD. NASICON reflections are not detected for Tcalc=900°C and for relatively short tcalc values of 2 h. At 1100°C, the onset of low intensity NASICON peaks indicate the early stages of the formation reaction which is significantly enhanced when Tcalc increases up to 1200 and 1300°C. For higher temperatures, an apparent decrease of the reaction rate is suggested. On the other hand, the intensities of the ZrO2 peaks suffer a drastic decrease when Tcalc varies from 900 to 1300°C, followed by a slight increase for Tcalc=1400°C. The studies were extended for mixtures kept in isothermal conditions at 1100, 1200 and 1300°C during 0.5, 1, 2, 4, 8 and 16 h. In the three temperatures, the increase of the tcalc up to ca. 4 h leads to a significant increase in the intensity of the NASICON reflections while that of mZrO2 decreases. A plateau is apparent for higher tcalc values suggesting that equilibrium may be attained. The use of a highly reactive tetragonal zirconia powder (also thermodynamically unstable at low temperature clearly improved the overall reaction extension and kinetics at moderate temperatures, yielding a single phase product.

    Polvos de ZrO2 monoclínica altamente reactivos fueron mezclados con Na3PO4•12H2O y SiO2 amorfo en cantidades apropiadas para obtener Na3Zr2Si2PO12. Las mezclas fueron calcinadas a diferentes temperaturas (Tcalc y diferentes tiempos (tcalc y caracterizadas por SEM y DRX. Líneas características del NASICON no son detectadas a Tcalc=900°C y a tiempos de calcinado relativamente cortos (< 2h. A 1100°C, la presencia de picos de NASICON de baja intensidad indica los primeros momentos de la reacción de formación, la cual es significativamente mejorada cuando Tcalc es aumentada a 1200 y 1300°C. Para altas temperaturas (< 1300ºC, se sugiere una aparente disminución de la velocidad de reacción. Por otra parte, la intensidad de los picos de ZrO2 sufren una drástica disminución cuando Tcalc varía desde 900 a 1300°C, seguido de un leve incremento a Tcalc=1400°C. Los estudios fueron realizados manteniendo condiciones isotérmicas a 1100, 1200 y 1300°C durante 0,5, 1, 2, 4, 8 y 16 h. En las tres temperaturas, el aumento de tcalc hasta 4 h conduce a un marcado aumento de la intensidad de las líneas características del NASICON, mientras que las correspondientes a mZrO2 disminuyen. Un “plateau” es observado a valores altos de tcalc, lo que sugiere que un equilibrio está siendo alcanzado. La utilización de polvos altamente reactivos de ZrO2 tetragonal (termodinámicamente inestable a baja temperatura mejoró claramente la extensión y la cinética de reacción a temperaturas moderadas, conduciendo a la formación de un producto monofásico.

  3. Study of defects in Zr lacunar Nasicon crystals

    Samples of Nasicon compounds NaxZr2-ySi3-zPzO12, with x-4y+z=4, were investigated by radioluminescence and thermoluminescence experiments. It has been found that disorder in the Zr lacunar sublattice originates charged defects active as centres of electron-hole radiative recombinations in excited crystals. The analysis of radio luminescent spectra shows that the minimum displacements of Na+ ions exceed 5 A. This results yields information on the paths of Na+ ions in the ionic conduction of these materials

  4. Parsing with Typed Feature Structures

    Wintner, S; Wintner, Shuly; Francez, Nissim

    1996-01-01

    In this paper we provide for parsing with respect to grammars expressed in a general TFS-based formalism, a restriction of ALE. Our motivation being the design of an abstract (WAM-like) machine for the formalism, we consider parsing as a computational process and use it as an operational semantics to guide the design of the control structures for the abstract machine. We emphasize the notion of abstract typed feature structures (AFSs) that encode the essential information of TFSs and define unification over AFSs rather than over TFSs. We then introduce an explicit construct of multi-rooted feature structures (MRSs) that naturally extend TFSs and use them to represent phrasal signs as well as grammar rules. We also employ abstractions of MRSs and give the mathematical foundations needed for manipulating them. We then present a simple bottom-up chart parser as a model for computation: grammars written in the TFS-based formalism are executed by the parser. Finally, we show that the parser is correct.

  5. Parsing with Typed Feature Structures

    Wintner, S; Wintner, Shuly; Francez, Nissim

    1996-01-01

    In this paper we provide for parsing with respect to grammars expressed in a general TFS-based formalism, a restriction of ALE. Our motivation being the design of an abstract (WAM-like) machine for the formalism, we consider parsing as a computational process and use it as an operational semantics to guide the design of the control structures for the abstract machine. We emphasize the notion of abstract typed feature structures (AFSs) that encode the essential information of TFSs and define unification over AFSs rather than over TFSs. We then introduce an explicit construct of multi-rooted feature structures (MRSs) that naturally extend TFSs and use them to represent phrasal signs as well as grammar rules. We also employ abstractions of MRSs and give the mathematical foundations needed for manipulating them. We formally define grammars and the languages they generate, and then describe a model for computation that corresponds to bottom-up chart parsing: grammars written in the TFS-based formalism are executed...

  6. Time of flight neutron Rietveld refinement study at elevated temperature on a monoclinic near-stoichiometric NASICON

    Time of flight neutron powder data were collected at elevated temperatures on a sample of NASICON of composition Na/sub 3.17/Zr/sub 1.93/Si/sub 1.9/O12. This sample, prepared by reheating a commercially available NASICON to minimize the ZrO2 impurity, has been previously structurally refined from room temperature neutron diffraction data collected at Argonne National Laboratory. Conductivity measurements show a cusp at ca. 1700C attributed to the monoclinic-rhombohedral transition and the purpose of this work was to explore the nature of the transition. Data runs were made at 143, 173, 202, 300, and 3910C. No evidence for a crystal system change was found. The highest temperature data sets could not be refined satisfactorily by the Rietveld method using a rhombohedral model, but rather required a monoclinic cell in space group C2/c to achieve convergence. An explanation for the conductivity cusp is given in terms of disordering of the sodium ions and a change in conduction pathways which lowers the barriers to ion movement

  7. Structural and electrochromic properties of Fe2(SO4)3 nanostructures prepared by template assisted method

    Sahana M., B.; Chandran, Sudakar; Naik, Ratna; Naik, Vaman

    2010-04-01

    Oxides containing polyanions such as XO4^2- (X = S, Mo, P and W) as lithium insertion hosts are promising cathode materials due to their high thermal stability. However, the larger separation of the transition metal ions can be expected to reduce the electron mobility. As observed in LiFePO4, this can be overcome either by coating the cathode materials with carbon or by decreasing the particle size. We have prepared nanowires of NASICON type structure and platelets of monoclinic Fe2(SO4)3 by template assisted electro deposition. These structures were grown on stainless steel substrates and are characterized by XPS, HRTEM, and XRD analysis. Both NASICON and monoclinic Fe2(SO4)3 structures are very porous and are comprised of nanoparticles leading to a high lithium insertion capacity.

  8. Positron annihilation studies on nasicon analogues containing cation vacancies

    Positron annihilation studies were carried out on the Nasicon analogue Na2(La, Al)Zr(PO4)3 compound for three different concentrations (2.2, 2.8 and 5.2 by wt.%) of ZrO2 in the nutrient. Angular correlation study of annihilated photons reveals that the defect concentration is maximum for 2.8(wt.%) of ZrO2. Further, positron lifetime studies indicate that the positrons are trapped at cation vacancies. Application of a two state trapping model to this system made it possible to evaluate the lifetime of positrons in the Bloch state and of positrons trapped at cation vacancies. (author). 16 refs., 4 figs

  9. High-voltage NASICON Sodium Ion Batteries: Merits of Fluorine Insertion

    Graphical abstract: Fluorine participation in crystal structure construction in Na3V2(PO4)3 to form Na3V2(PO4)2F3, displays several effects on the ions configuration involving ions occupation, species and amount of diverse Na sites, and the electronic cloud density upon compositional atoms leading to distinct modalities for ions extraction as well as the operating voltages. - Abstract: NASICON Na3V2(PO4)3 and Na3V2(PO4)2F3 have restarted to be investigated electrochemically as promising cathode materials for sodium-ion batteries. Fluorine insertion by replacing partial phosphate groups in Na3V2(PO4)3 allows for new family of host lattice structure, Na3V2(PO4)2F3. Greatly, fluorine is capable to participate in structural construction to change the ions configuration which involves ions occupation, the species and amount of diverse Na sites, leading to distinct modalities for ions extraction. The inductive effects of (PO4)3− polyanion by changing electronic cloud density upon compositional atoms could be enhanced under the effects of the formed F-V bond due to its strong ionicity, which can moderate the energetics of the transition metal redox couple to generate relatively high operating potentials. The substitution of fluorine for negative-charge polyanion or anion could be effective to improve the electrochemical properties, particularly for the purpose to increase performed voltages by changing atomic environments

  10. Preparation, Structural Characterization and Ionic Conductivity Studies of Calcium Doped LiZr2(PO4)3

    Prabu, M.; Reddy, M. V.; Selvasekarapandian, S.; Rao, G. V. Subba; Chowdari, B. V. R.

    2013-07-01

    Compounds with NASICON-type structure, Li1+2x (CaxZr2-x)(PO4)3, (x = 0.1 and 0.15) are prepared by the high temperature solid state reaction and are characterized by Rietveld refined X-ray diffraction, scanning electron microscopy and BET surface area techniques. Ca-substitution stabilizes the rhombohedral structure of the NASICON-phase. Ionic conductivities, σ (ionic) were determined in the temperature range of 27-300 °C by impedance spectroscopy. Results showed a σ ionic (total) at 300K of 0.4 × 10-6 S cm-1 and 0.2 × 10-6 S cm-1, respectively, for x = 0.1 and 0.15. The activation energy (Ea) = 0.57eV and 0.61eV, respectively in the temperature range 27-300 °C.

  11. An all-solid state NASICON sodium battery operating at 200 °C

    Lalère, F.; Leriche, J. B.; Courty, M.; Boulineau, S.; Viallet, V.; Masquelier, C.; Seznec, V.

    2014-02-01

    An all-solid state symmetric monolithic sodium ion battery operating at 200 °C is described, using NASICON-type electrodes and electrolyte. Na3V2(PO4)3 is used at both electrodes as the active material while Na3Zr2Si2PO12 stands the role of the Na+ solid electrolyte. Both compositions present order-disorder phase transitions and present decent ionic conductivity properties, 1.5 × 10-3 S cm-1 and 1.9 × 10-4 S cm-1 at 200 °C for Na3Zr2Si2PO12 and Na3V2(PO4)3, respectively. The full battery (560 μm in thickness) was assembled in a 10‧ single step by spark plasma sintering at 900 °C. The electrochemical characteristics at high temperature (200 °C) were evaluated thanks to a new experimental set-up. The battery operates at 1.8 V with 85% of the theoretical capacity attained at C/10 with satisfactory capacity retention, for an overall energy density of 1.87 × 10-3 W h cm-2 and a capacity of 1.04 mA h cm-2.

  12. Structural Integrity and Microstructure of NA^+ Conducting Ceramics

    Lipinska, Kristina; Kalita, Patricia; Hemmers, Oliver; Sinogeikin, Stanislav; Shebanova, Olga; Yang, Wenge; Mariotto, Gino

    2010-03-01

    Oxides with the general formula of Na1+x Zr2 Six P3-x O12 , known as Nasicon, are fast Na+ ion-conducting materials with important electrochemical applications and many functional properties, often attributed to their unique structural features. Comparative, in situ studies of the limits of structural integrity were performed for selected Nasicon materials, using synchrotron x-ray diffraction and diamond anvil cell technology. We show how different processing conditions produce crystalline structures with specific morphology. We discuss the bulk modulus, the compressibility and the influence of the volume fraction of primary and secondary crystalline phases on the overall Nasicon structural integrity.

  13. Structural trends in pyrochlore-type oxides

    Kennedy, Brendan J.

    1998-04-01

    Structural trends in some pyrochlore-type A2B2O7 oxides are reviewed and some new structural data is presented. Powder neutron diffraction data have shown that, for B=Ru or Ir, the presence of an easily polarisable cation on the pyrochlore A site and anion vacancies results in structural changes consistent with the oxidation of the B-type cation. An explanation for this observation is presented.

  14. Effect of substituting Ce for Zr on the electrical properties of NASICON materials

    Xie, Bingxing; Jiang, Danyu; Wu, Jian; Feng, Tao; Xia, Jinfeng; Nian, Hongqiang

    2016-01-01

    By investigation of the microstructure of cerium-doped NASICON materials prepared by solid state reaction, we find that variation in the cell parameters a, b and c can affect their activation energy (Ea) of ionic conductance. Furthermore, changes in the grain size and morphology can influence the pre-exponential factor σ0. Analysis of the electrical conductivity of cerium-doped NASICON grains reveals a decrease from that for the undoped grains. These results suggest that when dealing with Ce-doped NASICON system, the grain size and morphology play a more important role in determining the bulk conductivity than the lattice parameters, at least within a temperature range of 225-350 °C.

  15. Highly conducting divalent Mg2+ cation solid electrolytes with well-ordered three-dimensional network structure

    Tamura, Shinji; Yamane, Megumi; Hoshino, Yasunori; Imanaka, Nobuhito

    2016-03-01

    A three-dimensionally well-ordered NASICON-type Mg2+ cation conductor, (MgxHf1-x)4/(4-2x)Nb(PO4)3, was firstly developed by partial substitution of lower valent Mg2+ cation onto the Hf4+ sites in a HfNb(PO4)3 solid to realize high Mg2+ cation conductivity even at moderate temperatures. Due to the formation of well-ordered NASICON-type structure, both the high Mg2+ cation conductivity below 450 °C and the low activation energy for Mg2+ cation migration was successfully realized for the (Mg0.1Hf0.9)4/3.8Nb(PO4)3 solid. Pure Mg2+ cation conduction in the NASICON-type (Mg0.1Hf0.9)4/3.8Nb(PO4)3 solid was directly and quantitatively demonstrated by means of two kinds of dc electrolysis.

  16. The study of hydronium NASICON conductivity with deuterium

    The ionic conductivity of the bulk phase of bonded hydronium NASICON (HyceramTM) was measured at equilibrium with an H2O/N2 and then a D2O/N2 atmosphere, each at 100% relative humidity and 75% relative humidity over the temperature range 25-50deg C. At 100% relative humidity and 25deg C, the protonic system had a bulk conductivity of 5.0x10-4 S/cm and an activation energy of 17.3kJ mole; the same sample, when deuterated, had a bulk conductivity of 2.2x10-4 S/cm and an activation energy of 19.3 kJ/mole. At 75% relative humidity and 25deg C, the conductivity of the protonated system decreased to 1.4x10-4 S/cm with an activation energy of 24.1 kJ/mole. The deuterated sample at 75% relative humidity had a bulk conductivity of 5.4x10-5 S/cm with an activation energy of 26.0 kJ/mole. The isotope effect suggested a proton hopping (Grotthus) mechanism as the means by which the protons pass through the lattice. (author). 18 refs.; 3 figs.; 1 tab

  17. Lithium exchange processes in the conduction network of the Nasicon LiTi2-xZrx(PO4)3 Series (0 < or = x < or = 2).

    Arbi, K; París, M A; Sanz, J

    2006-04-01

    Structural sites occupied by lithium in the rhombohedral LiTi2-xZrx(PO4)3 series (0 Nasicon conduction network has been deduced. At high temperatures, analyzed phases tend toward a disordered rhombohedral phase, in which both M1 and M1/2 sites are equally populated and in which lithium mobility is favored by the existence of vacant M1 sites. According to this study, this phase can also be obtained by substituting Ti by Zr in the LiTi2-xZrx(PO4)3 series. PMID:16570941

  18. Effect of decomposition on the densification and properties of nasicon ceramic electrolytes

    Nasicon ceramic electrolytes were processed and characterized using a number of different techniques. The materials were sintered at T = 11000C to 13750C. Results of this work demonstrate that Nasicon ceramics with compositions around x = 2 (i.e. Na3Zr2Si2PO12), are not monophase, possess poor mechanical strength and an anomalous thermal expansion behavior, and are subject to chemical and phase instability during densification at high temperatures. Wet-chemical techniques, X-ray diffraction, and SEM analyses were used to observe the phase and chemical decomposition of these materials. The products of this decomposition process are correlated with the poor physical properties

  19. Síntesis mediante química sol gel de compuestos Li1+xMiiixTi2-x(PO43 con estructura tipo Nasicon. Estudio de la relación microestructura-propiedades eléctricas

    Santamaría, J.

    2010-02-01

    Full Text Available Compounds of formula Li1+xMIIIxTi2-x(PO43 with MIII = Cr, Fe and x = 0 and 0.05 have been prepared at soft temperatures using the Pechini synthesis method, based on sol-gel chemistry. The structural and microstructural characterization by X-ray diffraction and Scanning Electron Microscopy (SEM, shows that all of them crystallize in a NASICON-type structure with similar lattice parameters. Doping with Fe and Cr, causes an increase of the density of the samples after sinterization what clearly improves the ionic conductivity of the original material, LiTi2(PO43 until values of 9x10-4 S cm-1 at room temperature in the chromium-doped material.Haciendo uso de la química sol-gel, se han preparado ortofosfatos de composición LiTi2(PO43 y Li1.05(Cr/Fe0.05Ti1.95(PO43 a temperaturas moderadas mediante el método Pechini. Estas fases han sido caracterizadas estructural y microestructuralmente por difracción de rayos X de polvo y microscopía electrónica de barrido (SEM, encontrándose que todas cristalizan en una estructura tipo NASICON, con parámetros de red muy similares. El dopaje con Fe y Cr permite aumentar la densidad de las muestras en la sinterización, mejorando de forma apreciable su conductividad iónica. Se ha observado un incremento de hasta cuatro órdenes de magnitud en la conductividad a temperatura ambiente obteniéndose una energía de activación de 0.29 eV para el material dopado con Cr.

  20. Sol–gel chemistry synthesis and DTA–TGA, XRPD, SIC and 7Li, 31P, 29Si MAS–NMR studies on the Li-NASICON Li3Zr2−ySi2−4yP1+4yO12 (0 ⩽ y ⩽ 0.5) system

    Highlights: ► The samples of Li-NASICON were elaborated by sol–gel chemistry. ► The calcined temperatures of the studied samples were deduced from their thermograms. ► The recorded X-ray powder diffractograms were indexed in the rhombohedral system. ► The synthesized Li-NASICON materials are excellent lithium fast cation conductors. - Abstract: Five selected compounds of Li-NASICON, Li3Zr2−ySi2−4yP1+4yO12 (0 ⩽ y ⩽ 0.5), were synthesized by sol–gel chemistry in order to obtain pure polycrystalline powder and then analyzed by different physicochemical characterizations such as coupled DTA (differential thermal analysis)–TGA (thermogravimetric analysis), XRPD (X-ray powder diffraction), CIS (complex impedance spectroscopy) and MAS (magic angle spinning)–NMR (nuclear magnetic resonance). So the calcined temperature of each sample has been deduced from its corresponding DTA–TGA thermogram. However, the recorded X-ray powder diffractograms were indexed in the rhombohedral system with R3¯c space group which corresponds to the ideal structure of NASICON. Whereas, the complex impedance spectroscopy study showed that these Li-NASICON materials are excellent lithium fast cation conductors with total electric conductivity maximal value 1.97 × 10−3 S cm−1 at 293 K in the case of Li3Zr1.5P3O12. Furthermore, 7Li, 31P and 29Si MAS–NMR spectroscopy study and DFT/B3LYP theoretical calculations of chemical shifts were performed to discuss the ambiguousness that exists between the resonance peak number in the experimental spectrum and the crystallographic site number relative to Li3Zr2Si2PO12.

  1. Investigating The Algebraic Structure of Dihomotopy Types

    Gaucher, P

    2001-01-01

    This presentation is the sequel of a paper published in GETCO'00 proceedings where a research program to construct an appropriate algebraic setting for the study of deformations of higher dimensional automata was sketched. This paper will be focused precisely on detailing some of its aspects. The main idea is that the category of homotopy types can be embedded in a new category of dihomotopy types, the embedding being realized by the Globe functor. In this latter category, isomorphism classes of objects are exactly higher dimensional automata up to deformations leaving invariant their computer scientific properties as presence or not of deadlocks (or everything similar or related). Some hints to study the algebraic structure of dihomotopy types are given, in particular a rule to decide whether a statement/notion concerning dihomotopy types is or not the lifting of another statement/notion concerning homotopy types. This rule does not enable to guess what is the lifting of a given notion/statement, it only ena...

  2. Recycling Caustic from LAW Stream using NaSICON Membrane based Electrochemical Technology

    Ceramatec Inc. has developed and demonstrated an efficient electrochemical technology to separate sodium from Low Activity Waste (LAW) streams using a NaSICON (Sodium Super Ionic Conductor) ceramic membrane based electrolytic process. The NaSICON membrane process separates sodium contained in LAW streams thereby significantly reducing the quantity of LAW glass to be produced. The separated sodium is regenerated in the form of 'clean' sodium hydroxide and reused on site. Laboratory scale reliability and lifetime tests have been conducted at Ceramatec Inc. with multiple simulants representing baseline chemistries at site and have demonstrated the ability to recycle sodium from LAW streams. Three specific evaluations were conducted at Pacific Northwest National Laboratory (PNNL) to investigate the ability of NaSICON membrane based electrolytic cells to separate sodium from actual LAW streams. The average sodium transport efficiencies were 93% (non-radioactive test) and 99% (two radioactive tests). A maximum recoverable sodium quantity could be predicted by combining both an aluminate solubility model and a gibbsite crystal growth rate. Testing shows cell voltages were relatively stable until saturation ratios exceeded 9 and the cell was successfully operated at saturation ratios as high as 12. No transport of any cations or anions was detected except for Na and Cs-137. Decontamination factors on the order of 2000 were observed with respect to Cs-137. (authors)

  3. Determination of the p-electronic conduction parameter of NASICON by potentiometric measurements

    Using the galvanic cell: Pt vertical bar Au,CO2,O2 vertical bar aNa''' Na2CO3(Au) vertical bar aNa''NASICON vertical bar aNa'FeO+NiO(borateglass)|FeNi(48)|Au |Pt the p-electronic conduction parameter a-bar of NASICON was characterized as a function of the sodium activity aNa'' and the temperature. For that purpose, the isothermal voltage response to successive variations of aNa'' by changing the composition of the CO2-O2 gas mixture was evaluated by a non-linear regression procedure. Within the temperature range under investigation (300-620 deg. C) it holds that: loga+ =11.076+/-0.1-(18278.0+/-1100)KT(T=+=-3.519+/-1.7-(7904+/-1400)KT(500 deg. C=2 sensor with NASICON as solid electrolyte the sodium activity prevailing at the measuring electrode is outside the ionic domain of the electrolyte. This is in apparent contradiction to most of the literature reports on the behavior of such gas sensors, but confirms previous findings on the extent of the electronic conductivity in Na-beta-alumina under comparable conditions

  4. Extraordinary electronic properties in uncommon structure types

    Ali, Mazhar Nawaz

    In this thesis I present the results of explorations into several uncommon structure types. In Chapter 1 I go through the underlying idea of how we search for new compounds with exotic properties in solid state chemistry. The ideas of exploring uncommon structure types, building up from the simple to the complex, using chemical intuition and thinking by analogy are discussed. Also, the history and basic concepts of superconductivity, Dirac semimetals, and magnetoresistance are briefly reviewed. In chapter 2, the 1s-InTaS2 structural family is introduced along with the discovery of a new member of the family, Ag0:79VS2; the synthesis, structure, and physical properties of two different polymorphs of the material are detailed. Also in this chapter, we report the observation of superconductivity in another 1s structure, PbTaSe2. This material is especially interesting due to it being very heavy (resulting in very strong spin orbit coulping (SOC)), layered, and noncentrosymmetric. Electronic structure calculations reveal the presence of a bulk 3D Dirac cone (very similar to graphene) that is gapped by SOC originating from the hexagonal Pb layer. In Chapter 3 we show the re-investigation of the crystal structure of the 3D Dirac semimetal, Cd3As2. It is found to be centrosymmetric, rather than noncentrosymmetric, and as such all bands are spin degenerate and there is a 4-fold degenerate bulk Dirac point at the Fermi level, making Cd3As2 a 3D electronic analog to graphene. Also, for the first time, scanning tunneling microscopy experiments identify a 2x2 surface reconstruction in what we identify as the (112) cleavage plane of single crystals; needle crystals grow with a [110] long axis direction. Lastly, in chapter 4 we report the discovery of "titanic" (sadly dubbed ?rge, nonsaturating" by Nature editors and given the acronym XMR) magnetoresistance (MR) in the non-magnetic, noncentrosymmetric, layered transition metal dichalcogenide WTe2; over 13 million% at 0.53 K in a magnetic field of 60 Tesla (the largest positive magnetoresistance ever reported). Unlike what is seen in other known materials, there is no saturation of the magnetoresistance value even at very high applied fields. In semimetals, very high MR may attributed to a balanced hole-electron "resonance" condition; as described here, WTe2 appears to be the first known material where this resonance is nearly perfect.

  5. A Mixed α/ β Superstructure in NASICON Ionic Conductors: Neutron Diffraction Study of Li 2FeTi(PO 4) 3 and Li 2FeZr(PO 4) 3

    Catti, Michele

    2001-02-01

    The lithium conductors Li2FeTi(PO4)3 and Li2FeZr(PO4)3, synthesized by solid-state reaction and characterized by X-ray powder diffractometry, were studied structurally at room temperature by neutron powder diffraction at high resolution (HRPD, ISIS Facility, U.K.). By trial-and-error and Rietveld refinements (Rp=0.111, R(F2)=0.112), the first compound (orthorhombic Pbca, Z=8; a=8.5515(1), b=8.6229(1), c=23.9116(3) Å) was shown to have a complex superstructure sharing features of both the α and β NASICON-type phases of LiZr2(PO4)3. Four (001) layers of PO4 and (Fe, Ti)O6 polyhedra are present per unit-cell, and they are related both by overline1 inversion centers (α structure) and by a glide planes (β structure). Ti4+ and Fe3+ order in the two interlayer regions, respectively. Owing to the structure complexity, only half of the lithium atoms could be refined in tetrahedral coordination with =1.99 Å. Li2FeZr(PO4)3 (orthorhombic Pbna, Z=4; a=8.70559(8), b=8.78572(9), c=12.2202(1) Å) proved to be similar to β-LiZr2(PO4)3; however, by Fourier synthesis and Rietveld refinement (Rp=0.0618, R(F2)=0.0574) Li was located in a fully ordered tetrahedral configuration with =2.01 Å, instead of being disordered as in the β phase of LiZr2(PO4)3.

  6. Interference enhanced thermoelectricity in quinoid type structures

    Strange, M., E-mail: strange@chem.ku.dk; Solomon, G. C. [Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø (Denmark); Seldenthuis, J. S.; Verzijl, C. J. O.; Thijssen, J. M. [Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft (Netherlands)

    2015-02-28

    Quantum interference (QI) effects in molecular junctions may be used to obtain large thermoelectric responses. We study the electrical conductance G and the thermoelectric response of a series of molecules featuring a quinoid core using density functional theory, as well as a semi-empirical interacting model Hamiltonian describing the π-system of the molecule which we treat in the GW approximation. Molecules with a quinoid type structure are shown to have two distinct destructive QI features close to the frontier orbital energies. These manifest themselves as two dips in the transmission, that remain separated, even when either electron donating or withdrawing side groups are added. We find that the position of the dips in the transmission and the frontier molecular levels can be chemically controlled by varying the electron donating or withdrawing character of the side groups as well as the conjugation length inside the molecule. This feature results in a very high thermoelectric power factor S{sup 2}G and figure of merit ZT, where S is the Seebeck coefficient, making quinoid type molecules potential candidates for efficient thermoelectric devices.

  7. Detection of very low concentration of water in ethanol by using NASICON probe

    Yadav, Parul; Bhatnagar, M. C.

    2013-02-01

    NASICON based low cost, highly sensitive sensor probe for detection of very small content of the water nearly ppm level in ethanol has been fabricated and characterized. The sensor utilizes the electrochemical cell method for detection of water content in ethanol. The results indicate nearly linear variation of emf with increase in water content upto 10 % with a sensitivity of 0.001mV per ppm. Such a high value of sensitivity is extremely useful in detection of water in medical science and chemical industries where ethanol is used as an organic solvent.

  8. SO2-sensing characteristics of NASICON sensors with ZnSnO3 sensing electrode

    A compact tubular sensor based on sodium super ionic conductor (NASICON) and ZnSnO3 sensing electrode was designed for the detection of sulfur dioxide. The NASICON and ZnSnO3 material were prepared by sol-gel method and were analyzed by the X-ray diffraction (XRD) analysis, respectively. And ZnSnO3 materials were analyzed by SEM. ZnSnO3 thick film was prepared to investigate characteristics of sulfur dioxide (SO2) at various operating temperatures. The sensor using ZnSnO3 gave excellent sensing properties to 5-50 ppm SO2 in air at 360-390 deg. C. The EMF value of the sensor was almost proportional to the logarithm of SO2 concentration, the sensitivity (slope) was 255 mV/decade at 375 deg. C. It was also seen that the sensor showed a good selectivity to SO2 against H2S, NO2, Cl2, NO and C7H8. The sensor had speedy response kinetics to SO2 too, the 90% response time to 5, 10, 20 and 50 ppm SO2 was 18, 10, 8 and 5 s, respectively, and the recovery time was 27, 99, 184 and 243 s, respectively. Finally, a sensing mechanism involved the mixed potential was proposed

  9. Mullite and mullite-type crystal structures

    Fischer, Reinhard X.; Gaede-Koehler, Andrea; Birkenstock, Johannes [Bremen Univ. (Germany). Fachbereich Geowissenschaften; Schneider, Hartmut [Bremen Univ. (Germany). Fachbereich Geowissenschaften; Koeln Univ. (Germany). Inst. fuer Kristallographie

    2012-04-15

    Synthetic mullites (Al{sub 4+2x}Si{sub 2-2x}O{sub 10-x}) belong to one of the most important groups of ceramic materials. Their crystal structure consists of chains of edge-sharing AlO{sub 6} octahedra interconnected by tetrahedral double chains of TO{sub 4} (T = Al, Si) tetrahedra. The occurrence of oxygen vacancies is associated with the formation of triclusters of TO{sub 4} groups. The distribution of oxygen vacancies and the distribution of Al and Si on the tetrahedral sites are partially ordered yielding an incommensurately modulated crystal structure with satellite reflections in diffraction patterns. The number of symmetrically independent distribution patterns of oxygen vacancies is given for a 2 x 2 x 2 and a 3 x 3 x 2 superstructure model. Many other compounds have chain structures similar to mullite. These compounds are assigned to subgroups, all derived from a hypothetical tetragonal aristotype structure. (orig.)

  10. Dual Lie Bialgebra Structures of Poisson Types

    Song, Guang'ai; Su, Yucai

    2015-01-01

    Let $A=F[x,y]$ be the polynomial algebra on two variables $x,y$ over an algebraically closed field $F$ of characteristic zero. Under the Poisson bracket, $A$ is equipped with a natural Lie algebra structure. It is proven that the maximal good subspace of $A^*$ induced from the multiplication of the associative commutative algebra $A$ coincides with the maximal good subspace of $A^*$ induced from the Poisson bracket of the Poisson Lie algebra $A$. Based on this, structures of dual Lie bialgebr...

  11. Types and Functions of Coastal Structures

    Burcharth, H. F.; A. Hughes, Steven

    2003-01-01

    Coastal structures are used in coastal defence schemes with the objective of preventing shoreline erosion and flooding of the hinterland. Other objectives include sheltering of harbour basins and harbour entrances against waves, stabilization of navigation channels at inlets, and protection of...

  12. Hodge-type structures as link invariants

    Borodzik, Maciej; Nemethi, Andras

    2010-01-01

    Based on some analogies with the Hodge theory of isolated hypersurface singularities, we define Hodge-type numerical invariants (called H-numbers) of any, not necessarily algebraic, link in $S^3$. They contain the same information as the (normalized) real Seifert matrix. We study their basic properties, we express the Tristram-Levine signatures and the higher order Alexander polynomial in terms of them. Motivated by singularity theory, we also introduce the spectrum of the link (determined fr...

  13. New structure type of Lu5Ni19B6

    The powder method was used to investigate Lu5-Ni19B6 structure belonging to a new type: sp. g. P6/mmm, a=0.4943(1), c=1.7161(9) nm, N=30 (R=0.120). The L45Ni19B6 structure is a new representative of the homologous series based on CaCu5 and CeCo3B2 types; its elementary cell contains two layers of CaCu5 type structure and three layers of CeCo3B2 type structure. Structure of the new L45Ni19B6 type belongs to the class of structures with trigonal-prismatic coordination of smallest atoms

  14. Vibrational spectra of complex oxides with the perovskite type structure

    Some aspects of crystal chemistry and vibrational spectroscopy of complex oxides with the perovskite type structure are considered. A review of the investigation results of complex oxides of rhenium, tungsten, niobium, and tantalum with the perovskite type structure obtained by the vibrational spectroscopy methods (IR absorption, Raman spectroscopy) is presented. 34 refs.; 4 tabs

  15. Caustic Recycle from Hanford Tank Waste Using NaSICON Ceramic Membrane Salt Splitting Process

    A family of inorganic ceramic materials, called sodium (Na) Super Ion Conductors (NaSICON), has been studied at Pacific Northwest National Laboratory (PNNL) to investigate their ability to separate sodium from radioactively contaminated sodium salt solutions for treating U.S. Department of Energy (DOE) tank wastes. Ceramatec Inc. developed and fabricated a membrane containing a proprietary NAS-GY material formulation that was electrochemically tested in a bench-scale apparatus with both a simulant and a radioactive tank-waste solution to determine the membrane performance when removing sodium from DOE tank wastes. Implementing this sodium separation process can result in significant cost savings by reducing the disposal volume of low-activity wastes and by producing a NaOH feedstock product for recycle into waste treatment processes such as sludge leaching, regenerating ion exchange resins, inhibiting corrosion in carbon-steel tanks, or retrieving tank wastes

  16. Complex impedance analysis of the ionic conductivity of the material conductor: Nasicon

    Full text.The ionic conductivity of pressed pellets of Nasicon, Na1+xSixZr2P3-xO12 (1,4 +, have been determined by the measurement of their complex impedance in the range: 5 hz to 13 MHz. The electrodes were graphite layers and the voltage signal was chosen in the linear condition (0,1 volt). In most cases the intergrain resistance was as high or higher than the grain resistance. As mentioned by Bayard and al: for examples X = 2 sintered at 1000 celsius degree one semi-circle is observed in a Nyquist diagram. For examples sintered at 1200 celsius degree, there are generally two semi-circles. The semi-circle observed at low frequency (about 10 to 100 Khz) is certainly due to a grain boundary phase (according to x-ray an microprobe analysis)

  17. Noise of surface bio-potential electrodes based on NASICON ceramic and Ag-AgCl.

    Gondran, C; Siebert, E; Yacoub, S; Novakov, E

    1996-11-01

    The electrochemical noise from dry NASICON-based surface electrodes and pregelled Ag-AgCl electrodes is evaluated in saline solutions and on the skin. The electrochemical noise from the electrode/electrolyte interface is found to be negligible (less than 1 microV peak to peak). On the skin, the noise level is highly dependent on the patient. At high frequencies, the skin/electrode interface noise is equal to 'thermal noise' and can be related to the real part of the skin/electrode impedance. At low frequencies (F < 100 Hz), excess noise is observed that varies as f-2. It is tentatively ascribed to a non-stationary process or noise of electrochemical origin due to the ionic nature of the skin. The contribution of residual EMG signal of low amplitude (5 microV peak to peak) is suggested for electrodes with large surface area. PMID:9039749

  18. Caustic Recycle from Hanford Tank Waste Using NaSICON Ceramic Membrane Salt Splitting Process

    Fountain, Matthew S.; Kurath, Dean E.; Sevigny, Gary J.; Poloski, Adam P.; Pendleton, J.; Balagopal, S.; Quist, M.; Clay, D.

    2009-02-20

    A family of inorganic ceramic materials, called sodium (Na) Super Ion Conductors (NaSICON), has been studied at Pacific Northwest National Laboratory (PNNL) to investigate their ability to separate sodium from radioactively contaminated sodium salt solutions for treating U.S. Department of Energy (DOE) tank wastes. Ceramatec Inc. developed and fabricated a membrane containing a proprietary NAS-GY material formulation that was electrochemically tested in a bench-scale apparatus with both a simulant and a radioactive tank-waste solution to determine the membrane performance when removing sodium from DOE tank wastes. Implementing this sodium separation process can result in significant cost savings by reducing the disposal volume of low-activity wastes and by producing a NaOH feedstock product for recycle into waste treatment processes such as sludge leaching, regenerating ion exchange resins, inhibiting corrosion in carbon-steel tanks, or retrieving tank wastes.

  19. Stochastic Fatigue Analysis of Jacket Type Offshore Structures

    Sigurdsson, Gudfinnur

    In this paper, a stochastic reliability assessment for jacket type offshore structures subjected to wave loads in deep water environments is outlined. In the reliability assessment, structural and loading uncertainties are taken into account by means of some stochastic variables. To estimate...... statistical measures of structural stress variations the modal spectral analysis method is applied....

  20. Co-linear spin configurations in corundum-type structures

    The colinear magnetic configurations possible in corundum-type structures (?-Fe2O3; Cr2O3) are solutions of a matrices problem. Their regions of stability are bounded by inequality relationships between exchange integrals. (author)

  1. Spin ordering between sub-lattices in nasicon Li3Fe2(PO4)3 measured by Mössbauer spectroscopy

    Kim, Hee Seung; Kim, Chul Sung

    2013-05-01

    The chemical stability and conductivity of nasicon-structured α-Li3Fe2(PO4)3 make it a possible candidate for a cathode material in Li-battery. The x-ray diffraction pattern of Li3Fe2(PO4)3 showed the monoclinic structure with space group of P21/n. In the zero-field-cooled (ZFC) curve, the magnetization remained constant while the temperature was increased up to the splitting temperature (TS = 11 K) of two sub-lattices, indicating the antiferromagnetic behavior below TS. Magnetization curves of both ZFC and FC from 4.2 to 295 K showed ferrimagnetic behavior below the Néel temperature (TN = 29.5 K). We observed the change in the slope of the temperature-dependent Hhf curve at TS. These results suggest that the change in the spin ordering in Li3Fe2(PO4)3 is originated from the difference in hyperfine interactions between the localized Fe3+ magnetic ions at each of two sub-lattices. The spectra of Li3Fe2(PO4)3 under applied magnetic field of 5 T exhibit the magnetic phase transition around TS, indicating antiferromagnetic behavior below TS and ferrimagnetic behavior between TS and TN.

  2. Cation mobility in NASICON compounds Li1-xZr2-xNbx(PO4)3 and Li1+xZr2-xScx(PO4)3

    Compounds featuring NASICON structure of the composition Li1-xZr2-xNbx(PO4)3 and Li1+xZr2-xScx(PO4)3 were studied by the method of X-ray phase analysis and 7Li and 31P NMR. Structure of Li0.8Zr1.8Nb0.2(PO4)3 was refined on the basis of X-ray powder pattern. It is shown that cationic disordering in LiZr2(PO4)3 is stimulated both by cationic vacancies and interstitial atoms formation. The cationic vacancies are characterized by a higher mobility. The level of intrinsic disordering was estimated and the Frenkel constant for the compound was calculated

  3. Structures of the lovozerite type - a quantitative investigation

    The structure of lovozerite is derived from perovskite. For 24 members of the lovozerite family an aristotype is postulated. The method of quantitative comparison using the concept of mappings is applied to the lovozerite family using the aristotype as a 'structural unit'. The method is extended to relationships of symmetry-type II, i.e. the derived structure and the aristotype have only a common subgroup, the remaining non-common symmetry of the derived structure is used as 'distribution' symmetry for the structural unit. The numerical results are discussed in detail. (orig.)

  4. Implementing semantic frames as typed feature structures with XMG

    Timm Lichte

    2015-07-01

    Full Text Available This work presents results on the integration of frame-based representations into the framework of eXtensible MetaGrammar (XMG. Originally XMG allowed for the description of tree-based syntactic structures and underspecified representations of predicate-logical formulae, but the representation of frames as a sort of typed feature structure, particularly type unification, was not supported. Therefore, we introduce an extension that is capable of handling frame representations directly by means of a novel -dimension. The aim is not only to make possible a straightforward specification of frame descriptions, but also to offer various ways to specify constraints on types, be it as a contiguous type hierarchy or a loose set of feature structure constraints. The presented extensions to XMG are fully operational in a new prototype.

  5. Characteristics of Thick Film CO2 Sensors Based on Nasicon Using Li2CO3-CaCO3 Auxiliary Phases

    Kim, Han Ji; Shim, Han Byel; Choi, Jung Woon; Yoo, Kwang Soo; Kim, Shin Do

    2006-06-01

    Potentiometric devices were fabricated using a NASICON (Na1+xZr2SixP3-xO12) thick film and auxiliary layers. The powder of a precursor of NASICON with high purity was synthesized using the sol-gel method. Using the NASICON paste, an electrolyte was prepared on the alumina substrate through screen printing and then sintered at 1,000°C for 4 hours. In the present study, a series of Li2CO3-CaCO3 system was deposited on the Pt sensing electrode. Within a wide range of CO2 volume ratio concentration from 1,000 ppm to 10,000 ppm, the output of the sensor showed good electromotive force (EMF) response that was very close to the theoretical value. The device to which Li2CO3-CaCO3 (1:2) was attached showed good sensing properties at low temperatures.

  6. Structural modal reanalysis for large, simultaneous and multiple type modifications

    Jian-jun, He; Xiang-zi, Chen; Bin, Xu

    2015-10-01

    Eigenvalue problem is widely used to investigate the dynamic characteristics of large and complex structure. For finite element models, iterative solvers are needed to precisely calculate eigenvectors and eigenvalues. However, in cases such as large-scale reanalysis studies, or optimization design of huge structure, computational cost can quickly become too time consuming. This paper focus on the structural modal reanalysis for large and multiple modifications (including simultaneous boundary, topology and type modifications), which can greatly affect the eigen-modes of the modified structures. The proposed methods are based on the results from the modal analysis of the original structure, and the stiffness and mass matrix of the modified structures. A highly approximate eigensolution are generated by the proposed method, which is combined the newly added DOF (Degrees of Freedom) condensation, ICMO strategy (Independent and Coupling Mass Orthogonalization) with the Rayleigh-Ritz analysis. The numerical examples show that the proposed method is efficient with high precision even when large and multiple type modifications of the structural topology, boundary and type are made simultaneously.

  7. Caustic Recycle from Hanford Tank Waste Using NaSICON Ceramic Membranes

    A sodium (Na) Super Ion Conductor (NaSICON), has been studied at Pacific Northwest National Laboratory (PNNL) to investigate their ability to separate sodium from radioactively contaminated sodium salt solutions for treating U.S. Department of Energy (DOE) tank wastes. Ceramatec Inc. developed and fabricated a membrane disk containing a proprietary NAS-GY material formulation that was electrochemically tested in a bench-scale apparatus with both a simulant and a radioactive tank-waste solution to determine the membrane performance when removing sodium from DOE tank wastes. Implementing this sodium separation process can result in significant cost savings by reducing the disposal volume of low-activity wastes and by producing a 19M NaOH feedstock product for recycle into waste treatment processes such as sludge leaching, regenerating ion exchange resins, inhibiting corrosion in carbon-steel tanks, or retrieving tank wastes. In actual waste tests, average sodium transport rates of 10.3 kg/day/m2 were achieved at average sodium transport efficiencies of 99%. The membrane was found to be highly selective to sodium ions resulting in no detectable cation transport except Na and a small quantity (0.04% to 0.06%) of 137Cs. An average decontamination factor of 2000 was observed with respect to 137Cs. As expected, Gibbsite precipitation was observed as OH- ions were depleted from the tank waste

  8. Caustic Recycle from Hanford Tank Waste Using NaSICON Ceramic Membranes

    Fountain, Matthew S.; Kurath, Dean E.; Sevigny, Gary J.; Poloski, Adam P.; Pendleton, J.; Balagopal, S.; Quist, M.; Clay, D.

    2008-07-15

    A sodium (Na) Super Ion Conductor (NaSICON), has been studied at Pacific Northwest National Laboratory (PNNL) to investigate their ability to separate sodium from radioactively contaminated sodium salt solutions for treating U.S. Department of Energy (DOE) tank wastes. Ceramatec Inc. developed and fabricated a membrane disk containing a proprietary NAS-GY material formulation that was electrochemically tested in a bench-scale apparatus with both a simulant and a radioactive tank-waste solution to determine the membrane performance when removing sodium from DOE tank wastes. Implementing this sodium separation process can result in significant cost savings by reducing the disposal volume of low-activity wastes and by producing a 19M NaOH feedstock product for recycle into waste treatment processes such as sludge leaching, regenerating ion exchange resins, inhibiting corrosion in carbon-steel tanks, or retrieving tank wastes. In actual waste tests, average sodium transport rates of 10.3 kg/day/m2 were achieved at average sodium transport efficiencies of 99%. The membrane was found to be highly selective to sodium ions resulting in no detectable cation transport except Na and a small quantity (0.04% to 0.06%) of 137Cs. An average decontamination factor of 2000 was observed with respect to 137Cs. As expected, Gibbsite precipitation was observed as OH- ions were depleted from the tank waste.

  9. Lithium Ion Materials for Energy Applications: Structural Properties from Neutron Diffraction

    Catti, Michele

    Cathode materials and solid electrolytes to be used in lithium batteries require a high ionic mobility of Li^+ species in their crystal structures. This in turn depends on the order-disorder state of lithium and on its bonding environment. Neutron diffraction is the choice technique to study the structural features of polycrystalline lithium materials that control their performance in ion transport processes. The basic principles of ionic mobility in solids and of the Rietveld refinement methods for neutron diffraction data are briefly reviewed. Then two important families of lithium conductors are selected from the literature and thoroughly discussed: the LLTO perovskite-type Li_xLa_{2/3-x/3}TiO_3 system and the Li_{1+x}Me_2(PO_4)_3 Nasicon phases. Accurate neutron diffraction determinations of the corresponding crystal structures have been shown to provide a considerable insight into the mechanisms of Li^+ ion transfer in such materials.

  10. Homogeneous pseudo-Riemannian structures of linear type

    Batat, Wafaa; Gadea, Pedro M.; Oubiña, Jose Antonio

    2010-01-01

    Homogeneous pseudo-Riemannian structures of linear type are reviewed and studied. In the Riemannian case, they furnish characterisations of the real, complex and quaternionic hyperbolic spaces. In the Lorentzian case, a related class gives characterisations of singular homogeneous plane waves.

  11. Interspecies radioimmunoassay for the major structural proteins of primate type-D retroviruses

    A competition radioimmunoassay has been developed in which type-D retroviruses from three primate species compete. The assay utilizes the major structural protein (36,000 daltons) of the endogenous squirrel monkey retrovirus and antisera directed against the major structural protein (27,000 daltons) of the Mason-Pfizer monkey virus isolated from rhesus monkeys. Purified preparations of both viruses grown in heterologous cells, as well as extracts of heterologous cells infected with squirrel monkey retrovirus or Mason-Pfizer monkey virus, compete completely in the assay. Addition of an endogenous virus of the langur monkey also results in complete blocking. No blocking in the assay is observed with type-C baboon viruses, woolly monkey virus, and gibbon virus. Various other type-C and type-B viruses also showed no reactivity. An interspecies assay has thus been developed that recognizes the type-D retroviruses from both Old World monkey (rhesus and langur) and New World monkey (squirrel) species

  12. Sol-gel chemistry synthesis and DTA-TGA, XRPD, SIC and {sup 7}Li, {sup 31}P, {sup 29}Si MAS-NMR studies on the Li-NASICON Li{sub 3}Zr{sub 2-y}Si{sub 2-4y}P{sub 1+4y}O{sub 12} (0 Less-Than-Or-Slanted-Equal-To y Less-Than-Or-Slanted-Equal-To 0.5) system

    Belam, W., E-mail: WahidBelam@yahoo.fr [Chemistry Department, Bizerta Science Faculty, 7021 Jarzouna, Bizerta (Tunisia)

    2013-02-25

    Highlights: Black-Right-Pointing-Pointer The samples of Li-NASICON were elaborated by sol-gel chemistry. Black-Right-Pointing-Pointer The calcined temperatures of the studied samples were deduced from their thermograms. Black-Right-Pointing-Pointer The recorded X-ray powder diffractograms were indexed in the rhombohedral system. Black-Right-Pointing-Pointer The synthesized Li-NASICON materials are excellent lithium fast cation conductors. - Abstract: Five selected compounds of Li-NASICON, Li{sub 3}Zr{sub 2-y}Si{sub 2-4y}P{sub 1+4y}O{sub 12} (0 Less-Than-Or-Slanted-Equal-To y Less-Than-Or-Slanted-Equal-To 0.5), were synthesized by sol-gel chemistry in order to obtain pure polycrystalline powder and then analyzed by different physicochemical characterizations such as coupled DTA (differential thermal analysis)-TGA (thermogravimetric analysis), XRPD (X-ray powder diffraction), CIS (complex impedance spectroscopy) and MAS (magic angle spinning)-NMR (nuclear magnetic resonance). So the calcined temperature of each sample has been deduced from its corresponding DTA-TGA thermogram. However, the recorded X-ray powder diffractograms were indexed in the rhombohedral system with R3{sup Macron }c space group which corresponds to the ideal structure of NASICON. Whereas, the complex impedance spectroscopy study showed that these Li-NASICON materials are excellent lithium fast cation conductors with total electric conductivity maximal value 1.97 Multiplication-Sign 10{sup -3} S cm{sup -1} at 293 K in the case of Li{sub 3}Zr{sub 1.5}P{sub 3}O{sub 12}. Furthermore, {sup 7}Li, {sup 31}P and {sup 29}Si MAS-NMR spectroscopy study and DFT/B3LYP theoretical calculations of chemical shifts were performed to discuss the ambiguousness that exists between the resonance peak number in the experimental spectrum and the crystallographic site number relative to Li{sub 3}Zr{sub 2}Si{sub 2}PO{sub 12}.

  13. Atomic structures of icosahedral phases of type F and dislocations

    The object of this thesis is the study of atomic structures of icosahedral phases of type F and their dislocations. In this study, we have first built a prototypical structure that describes the already known F type icosahedral phases. In order to check it we synthesized some of the new compositions predicted by this model. This synthesis led to the discovery of two new quasi-periodical phases of the stoichiometry Al66,08Cu21,35Mn8,29Fe4,28. One of these phases is icosahedral (metastable) of type F and the other one is decagonal (stable). A F-IQC phase is present on these compounds that have a different composition with respect to the ones already studied for the system (Al,Pd,Fe). Globally, these experimental results on new icosahedral phases allowed to prove the viability of the model: on the three samples of new composition, two of them have shown the existence of icosahedral phases of type F and the third one has given a decagonal phase, in relation of canonical orientation with the icosahedral metastable phase (10-fold axis parallel with 5-fold axis). Using this reliable model, we have been able to introduce dislocations. We could thus provide the geometry of dislocations (outside the dislocation core) at atomic scale for F-IQC phases. On this structure we have also identified the distributions of phasons and given some elements of answer for the global dislocations moves. (author)

  14. Extended, regular HI structures around early-type galaxies

    Oosterloo, T; Morganti, R.; Sadler, E. M.; van der Hulst, J. M.; Serra, P.

    2007-01-01

    We discuss the morphology and kinematics of the HI of a sample of 30 southern gas-rich early-type galaxies selected from the HI Parkes All-Sky Survey (HIPASS). This is the largest collection of high-resolution HI data of a homogeneously selected sample. Given the sensitivity of HIPASS, these galaxies represent the most HI-rich early-type galaxies. In two-thirds of the galaxies, we find the HI to be in a large, regular disk- or ring-like structure that in some cases is strongly warped. In the ...

  15. Structured Type 1 Diabetes Education Delivered Within Routine Care

    Cooke, Debbie; Bond, Rod; Lawton, Julia; Rankin, David; Heller, Simon; Clarke, Marie; Speight, Jane

    2013-01-01

    OBJECTIVE To determine whether improvements in glycemic control and diabetes-specific quality of life (QoL) scores reported in research studies for the type 1 diabetes structured education program Dose Adjustment for Normal Eating (DAFNE) are also found when the intervention is delivered within routine U.K. health care. RESEARCH DESIGN AND METHODS Before and after evaluation of DAFNE to assess impact on glycemic control and QoL among 262 adults with type 1 diabetes.RESULTS There were signific...

  16. Equipment and building structures ageing management for WWER type NPPs

    This report presents the working group 'Equipment and building structures ageing management for WWER type NPPs' activities. The analysis of experience in ageing management, recommendations for regulatory guidelines on ageing management, investigation of case studies, definition suitable communication channels among regulators for ageing related data are given. Analyses of water chemistry, inspection data (safety margins criteria), plugging criteria, volume and time of ECT implementation in all WWER countries are presented. The results of Working group activity show that it is advisable to concentrate efforts on: set up the permanent communication channel among regulators, collection of regulatory criteria for WWER type NPP key components based on understanding of ageing mechanisms and data collection

  17. NMR investigations of Li(+) ion dynamics in the NASICON ionic conductors [Formula: see text].

    Barré, Maud; Emery, Joël; Florian, Pierre; Le Berre, Françoise; Crosnier-Lopez, Marie-Pierre; Fourquet, Jean-Louis

    2009-04-29

    NMR studies of (7)Li and (31)P nuclei are reported in the 150-900 K temperature range for the [Formula: see text] NASICON compounds with x = 0.8, 0.7, 0.6 and 0.3. Magic angle spinning (MAS mode) experiments were performed at room temperature on the (7)Li and (31)P nuclei. The linewidth and the spin lattice relaxation times of these nuclei are studied versus temperature in the static mode. The spectra recorded in the MAS mode show that the (7)Li ions occupy three chemical sites, the occupation of which being very sensitive to the x values but not sensitive to the coexistence of the two varieties [Formula: see text] and [Formula: see text] observed at room temperature in compounds with x≤0.5. On the other hand, the (31)P nucleus MAS spectra are very sensitive to lithium content but also to the variety coexistence. T(1) measurements were performed in a static mode on the (7)Li and (31)P nuclei. In all the compounds, the (7)Li spin lattice relaxation time exhibits two branches with several minima, indicating the complex dynamics for this ion. One of these minima appears in the same temperature range as the minimum of the (31)P nucleus T(1), strongly suggesting a cross-relaxation process between these nuclei. T(1ρ) measurements on (7)Li (static mode) allow us to show a slow motion different from the one probed by the T(1). The analysis of the T(1ρ) behaviour with temperature and composition allows us to ascribe the motion probed by this time to the oxygen ion motion which monitors the opening and closing of the lithium pathways. A qualitative interpretation of the (7)Li  T(1) results is done; it takes into account the cross-relaxation phenomena between (31)P and (7)Li and quadrupolar fluctuations. PMID:21825419

  18. Excitonic fine structure splitting in type-II quantum dots

    Křápek, V.; Klenovský, P.; Šikola, T.

    2015-11-01

    Excitonic fine structure splitting in quantum dots is closely related to the lateral shape of the wave functions. We have studied theoretically the fine structure splitting in InAs quantum dots with a type-II confinement imposed by a GaAsSb capping layer. We show that very small values of the fine structure splitting comparable with the natural linewidth of the excitonic transitions are achievable for realistic quantum dots despite the structural elongation and the piezoelectric field. For example, varying the capping layer thickness allows for a fine tuning of the splitting energy. The effect is explained by a strong sensitivity of the hole wave function to the quantum dot structure and a mutual compensation of the electron and hole anisotropies. The oscillator strength of the excitonic transitions in the studied quantum dots is comparable to those with a type-I confinement which makes the dots attractive for quantum communication technology as emitters of polarization-entangled photon pairs.

  19. Magnetic mirror structure for testing shell-type quadrupole coils

    Andreev, N.; Barzi, E.; Bossert, R.; Chlachidze, G.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Nobrega, F.; Novitski, I.; Tartaglia, N.; Turrioni, D.; /Fermilab

    2009-10-01

    This paper presents magnetic and mechanical designs and analyses of the quadrupole mirror structure to test single shell-type quadrupole coils. Several quadrupole coils made of different Nb{sub 3}Sn strands, cable insulation and pole materials were tested using this structure at 4.5 and 1.9 K. The coils were instrumented with voltage taps, spot heaters, temperature sensors and strain gauges to study their mechanical and thermal properties and quench performance. The results of the quadrupole mirror model assembly and test are reported and discussed.

  20. Effects of structure type on viscoelastic properties of geosynthetics

    I.I. Loginova

    2015-06-01

    Full Text Available This work presents a study on tensile properties of geosynthetic materials. There were investigated six samples of geofabrics and geogrids with different structures including woven geotextile fabrics, nonwoven geotextile fabrics, warp-knitted geogrids and extruded geogrid. The study determined tensile properties of geosynthetics including tensile strength, strain at the maximum load and tensile load at a specified strain. The authors carried out creep and relaxation tests. It was found that the structure type significantly affects viscoelastic properties of geosynthetics materials. The article presents some results of numerous tests, which may be used to pre-select geosynthetics materials.

  1. New compounds with YCrB4-type structure

    This paper investigates part of the Yb- Fe, Co, Ni -B ternary systems to obtain borides with YCrB4-type structure. Compact Yb of 99.94 mass % purity and precompacted powders of finely crystalline boron, Fe, Co, or Ni were fused in an electric-arc furnace in an atmosphere of purified argon. The results of x-ray phase-shift analysis showed that borides with YCrB4-type structure were formed in 11 of the studied systems. The obtained values of the unit-cell parameters for the compounds YbCoB4, YbFeB4, and YbNiB4 are inscribed smoothly in the curve of the change of unit-cell parameters and volumes of RMB4 compounds, which indicates a trivalent state of the ytterbium atoms in these borides

  2. Structure of a Kunitz-type potato cathepsin D inhibitor

    Guo, J.; Erskine, P. T.; Coker, A. R.; Wood, S. P.; Cooper, J. B.; Mareš, Michael; Baudyš, Miroslav

    2015-01-01

    Roč. 192, č. 3 (2015), s. 554-560. ISSN 1047-8477 R&D Projects: GA ČR GA15-18929S; GA MŠk LO1302 Institutional support: RVO:61388963 Keywords : potato cathepsin D inhibitor * Kunitz-type protease inhibitor * protein X-ray structure * reactive-site loop * docking Subject RIV: CE - Biochemistry Impact factor: 3.231, year: 2014

  3. SO{sub 2}-sensing characteristics of NASICON sensors with ZnSnO{sub 3} sensing electrode

    Zhong Tiegang [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012 (China)], E-mail: gangtie1984@email.jlu.edu.cn; Quan Baofu [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012 (China)], E-mail: Quanbf@mail.jlu.edu.cn; Liang Xishuang [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012 (China)], E-mail: xs_liang@email.jlu.edu.cn; Liu Fengmin [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012 (China)], E-mail: liufm@mail.jlu.edu.cn; Wang Biao [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012 (China)], E-mail: quanbf@mail.jlu.edu.cn

    2008-06-25

    A compact tubular sensor based on sodium super ionic conductor (NASICON) and ZnSnO{sub 3} sensing electrode was designed for the detection of sulfur dioxide. The NASICON and ZnSnO{sub 3} material were prepared by sol-gel method and were analyzed by the X-ray diffraction (XRD) analysis, respectively. And ZnSnO{sub 3} materials were analyzed by SEM. ZnSnO{sub 3} thick film was prepared to investigate characteristics of sulfur dioxide (SO{sub 2}) at various operating temperatures. The sensor using ZnSnO{sub 3} gave excellent sensing properties to 5-50 ppm SO{sub 2} in air at 360-390 deg. C. The EMF value of the sensor was almost proportional to the logarithm of SO{sub 2} concentration, the sensitivity (slope) was 255 mV/decade at 375 deg. C. It was also seen that the sensor showed a good selectivity to SO{sub 2} against H{sub 2}S, NO{sub 2}, Cl{sub 2}, NO and C{sub 7}H{sub 8}. The sensor had speedy response kinetics to SO{sub 2} too, the 90% response time to 5, 10, 20 and 50 ppm SO{sub 2} was 18, 10, 8 and 5 s, respectively, and the recovery time was 27, 99, 184 and 243 s, respectively. Finally, a sensing mechanism involved the mixed potential was proposed.

  4. Babel Fortran 2003 Binding for Structured Data Types

    Muszala, S; Epperly, T; Wang, N

    2008-05-02

    Babel is a tool aimed at the high-performance computing community that addresses the need for mixing programming languages (Java, Python, C, C++, Fortran 90, FORTRAN 77) in order to leverage the specific benefits of those languages. Scientific codes often rely on structured data types (structs, derived data types) to encapsulate data, and Babel has been lacking in this type of support until recently. We present a new language binding that focuses on their interoperability of C/C++ with Fortran 2003. The new binding builds on the existing Fortran 90 infrastructure by using the iso-c-binding module defined in the Fortran 2003 standard as the basis for C/C++ interoperability. We present the technical approach for the new binding and discuss our initial experiences in applying the binding in FACETS (Framework Application for Core-Edge Transport Simulations) to integrate C++ with legacy Fortran codes.

  5. The Three-Dimensional Structural Basis of Type II Hyperprolinemia

    Srivastava, Dhiraj; Singh, Ranjan K.; Moxley, Michael A.; Henzl, Michael T.; Becker, Donald F.; Tanner, John J. (UNL); (UMC)

    2012-08-31

    Type II hyperprolinemia is an autosomal recessive disorder caused by a deficiency in {Delta}{sup 1}-pyrroline-5-carboxylate dehydrogenase (P5CDH; also known as ALDH4A1), the aldehyde dehydrogenase that catalyzes the oxidation of glutamate semialdehyde to glutamate. Here, we report the first structure of human P5CDH (HsP5CDH) and investigate the impact of the hyperprolinemia-associated mutation of Ser352 to Leu on the structure and catalytic properties of the enzyme. The 2. 5-{angstrom}-resolution crystal structure of HsP5CDH was determined using experimental phasing. Structures of the mutant enzymes S352A (2.4 {angstrom}) and S352L (2.85 {angstrom}) were determined to elucidate the structural consequences of altering Ser352. Structures of the 93% identical mouse P5CDH complexed with sulfate ion (1.3 {angstrom} resolution), glutamate (1.5 {angstrom}), and NAD{sup +} (1.5 {angstrom}) were determined to obtain high-resolution views of the active site. Together, the structures show that Ser352 occupies a hydrophilic pocket and is connected via water-mediated hydrogen bonds to catalytic Cys348. Mutation of Ser352 to Leu is shown to abolish catalytic activity and eliminate NAD{sup +} binding. Analysis of the S352A mutant shows that these functional defects are caused by the introduction of the nonpolar Leu352 side chain rather than the removal of the Ser352 hydroxyl. The S352L structure shows that the mutation induces a dramatic 8-{angstrom} rearrangement of the catalytic loop. Because of this conformational change, Ser349 is not positioned to interact with the aldehyde substrate, conserved Glu447 is no longer poised to bind NAD{sup +}, and Cys348 faces the wrong direction for nucleophilic attack. These structural alterations render the enzyme inactive.

  6. Type II functional response for continuous, physiologically structured models.

    Logan, J David; Ledder, Glenn; Wolesensky, William

    2009-07-21

    The goal of this work is to formulate a general Holling-type functional, or behavioral, response for continuous physiologically structured populations, where both the predator and the prey have physiological densities and certain rules apply to their interactions. The physiological variable can be, for example, a development stage, weight, age, or a characteristic length. The model leads to a Fredholm integral equation for the functional response, and, when inserted into population balance laws, it produces a coupled system of partial differential-integral equations for the two species, with a nonlocal integral term that arises from rules of interaction in the functional response. The general model is, typically, analytically intractable, but specialization to a structured prey-unstructured predator model leads to some analytic results that reveal interesting and unexpected dynamics caused by the presence of size-dependent handling times in the functional response. In this case, steady-states are shown to exist over long times, similar to the stable age-structure solutions for the McKendick-von Foerster model with exponential growth rates determined by the Euler-Lotka equation. But, for type II responses, there are early transient oscillations in the number of births that bifurcate in a few generations into either the decaying or growing steady-state. The bifurcation parameter is the initial level of prey. This special case is applied to a problem of the biological control of a structured pest population (e.g., aphids) by a predator (e.g., lady beetles). PMID:19362565

  7. The Structure of Carbon Detonation in Type Ia Supernovae

    Fryxell, B.; Timmes, F. X.; Zingale, M.; Dursi, L. J.; Ricker, P.; Olson, K.; Calder, A. C.; Tufo, H.; Truran, J. W.; Rosner, R.; MacNeice, P.

    2000-12-01

    Type Ia Supernova explosions are thought to begin as deflagrations in the center of accreting white dwarfs. Observations suggest that at some point, the burning undergoes a transition from a deflagration to a detonation front. We describe high-resolution three-dimensional simulations of the structure of such a detonation. The pre-detonation material is assumed to be pure C12 at a density of 107 g cm-3. A cellular structure develops behind the front, leaving pockets of unburned fuel. The cellular instability is unlikely to have any observational consequences at this density, since the cell size is only a few centimeters. However, as the detonation approaches the surface, the cell size will become comparable to the radius of the star, leaving a nonspherical distribution of reaction products and modifying the spectral signature of the explosion. The calculations were performed on 1000 processors of ASCI Blue Pacific at Lawrence Livermore National Laboratory using the Flash Code developed at the Center for Astrophysical Thermonuclear Flashes at the University of Chicago. They represent by far the largest simulations ever carried out on the detailed structure of burning fronts in Type Ia supernovae. This work was supported in part by the Department of Energy Grant No. B341495 to the Center for Astrophysical Thermonuclear Flashes at the University of Chicago under the ASCI Strategic Alliances Program and by NASA/Goddard Space Flight Center.

  8. The Structure of Workaholism and Types of Workaholic

    Malinowska Diana

    2014-06-01

    Full Text Available The aim of the study presented was to verify empirically a conception of workaholism as a multidimensional syndrome. The study also investigated the notion of ‘functional’ and ‘dysfunctional’ types of workaholic, on the basis of the participants’ cognitive evaluations of their quality of life. The research group comprised Polish managers who had graduated with, or were studying to attain, a Master’s degree in Business Administration. The 137 participants completed a set of questionnaires that were based on five different research tools. Confirmatory factor analysis supported the theory that workaholism has a three-dimensional structure that includes behavioural, cognitive, and affective dimensions. Using cluster analysis, three types of worker were identified, two of which represented types of workaholic with different scores for the dimensions of workaholism and for aspects of quality of life. The research demonstrated that workaholism is a three-dimensional construct. It enabled the integration of different perspectives and also confirmed that dysfunctional and functional types of workaholic exist. Furthermore, this paper provides practical insights about workaholism for practitioners of human resources that can be used in the selection and evaluation of employees.

  9. Structural analysis of a new type lightweight optical mirror blank

    Li, Yeping; Cui, Xiangqun; Hu, Ningsheng

    2010-07-01

    To reduce the cost and increase the feasibility of the astronomical optical telescope, modern large optical telescope is normally required to be as light as possible. Therefore lightweight mirror is always pursued by large telescopes development. In this paper, a new type lightweight optical mirror blank, the evaluation of its technical feasibility and the reduction of cost are introduced. For the purpose of applying active optics with this lightweight mirror blank, the structural analysis, thermal analysis and optical performance simulation by the finite element method have been presented.

  10. Structure and organization of heteromeric AMPA-type glutamate receptors.

    Herguedas, Beatriz; García-Nafría, Javier; Cais, Ondrej; Fernández-Leiro, Rafael; Krieger, James; Ho, Hinze; Greger, Ingo H

    2016-04-29

    AMPA-type glutamate receptors (AMPARs), which are central mediators of rapid neurotransmission and synaptic plasticity, predominantly exist as heteromers of the subunits GluA1 to GluA4. Here we report the first AMPAR heteromer structures, which deviate substantially from existing GluA2 homomer structures. Crystal structures of the GluA2/3 and GluA2/4 N-terminal domains reveal a novel compact conformation with an alternating arrangement of the four subunits around a central axis. This organization is confirmed by cysteine cross-linking in full-length receptors, and it permitted us to determine the structure of an intact GluA2/3 receptor by cryogenic electron microscopy. Two models in the ligand-free state, at resolutions of 8.25 and 10.3 angstroms, exhibit substantial vertical compression and close associations between domain layers, reminiscent of N-methyl-D-aspartate receptors. Model 1 resembles a resting state and model 2 a desensitized state, thus providing snapshots of gating transitions in the nominal absence of ligand. Our data reveal organizational features of heteromeric AMPARs and provide a framework to decipher AMPAR architecture and signaling. PMID:26966189

  11. Crystallostructural features of ion transport in new OD-structures: catapleite Na2ZrSi3O92H2O and ilerite Na2ZrSi3O93H2O

    The formation of new OD-structures in the class of alkali MT-compounds (M=Zr, Sc, rare earths, T=Si, P) with disordered Na sublattice is analized. The experimental proof of ion conductivity presence is obtained and a reversible phase transition is registered for the synthetic catapleite analog crystallizing in the hydrothermal system ZrO2-SiO2-NaOH-H2O. Crystallostructural features of phase transitions in catapleite (of the shift type) and Zr- and Sc-NASICON (transitions of the order-disorder type) are considered. Compounds with two-dimensional Na-sublattices are found for the first time among three-dimensional MT-structures with disordered Na-sublattice which permits to use catapleite and ilerite crystals as the object for detail study of ion-transport characteristics anisotropy

  12. Bismuth zinc vanadate, BiZn2VO6: New crystal structure type and electronic structure

    We report a combined experimental and computational study of the crystal structure and electronic properties of bismuth zinc vanadate, BiZn2VO6, known for its visible light photocatalytic activity. The crystal structure has been solved from laboratory powder X-ray diffraction data using the repeated minimisations from random starting values method. BiZn2VO6 adopts a new structure type, based on the following building blocks: corner- and edge-sharing ZnO4 tetrahedra, ZnO6 octahedra and VO4 tetrahedra, and Bi2O12 dimers. It is the only known member of the BiM2AO6 (M=Pb, Ca, Cd, Mn, Zn, Mg, Cu; A=V, P, As) family which does not appear to be structurally closely related to others. The electronic structure of BiZn2VO6, calculated by DFT methods, shows that it is an indirect gap semiconductor with a calculated band gap of 1.6 eV, which compares favourably to the experimentally measured value of 2.4 eV. - Graphical abstract: The crystal structure of BiZn2VO6, a new structure type in the BiM2AO6 (M=Mg, Ca, Cd, Cu, Pb, Mn, Zn; A=V, P, As) family. - Highlights: • Structure solution from PXRD data by repeated minimisations from random starting values. • New structure type in the BiM2AO6 (M=Pb, Ca, Cd, Mn, Zn, Mg, Cu; A=V, P, As) family. • Electronic structure calculation

  13. The primary structure of cassowary (Casuarius casuarius) goose type lysozyme.

    Thammasirirak, Sompong; Torikata, Takao; Takami, Kazutoshi; Murata, Koichi; Araki, Tomohiro

    2002-01-01

    The complete amino acid sequence of cassowary (Casuarius casuarius) goose type lysozyme was analyzed by direct protein sequencing of peptides obtained by cleavage with trypsin, V8 protease, chymotrypsin, lysyl endopeptidase, and cyanogen bromide. The N-terminal residue of the enzyme was deduced to be a pyroglutamate group by analysis with a LC/MS/MS system equipped with the oMALDI ionization source, and then confirmed by a glutamate aminopeptidase enzyme. The blocked N-terminal is the first reported in this enzyme group. The positions of disulfide bonds in this enzyme were chemically identified as Cys4-Cys60 and Cys18-Cys29. Cassowary lysozyme was proved to consist of 185 amino acid residues and had a molecular mass of 20408 Da calculated from the amino acid sequence. The amino acid sequence of cassowary lysozyme compared to that of reported G-type lysozymes had identities of 90%, 83%, and 81%, for ostrich, goose, and black swan lysozymes, respectively. The amino acid substitutions at PyroGlu1, Glu19, Gly40, Asp82, Thr102, Thr156, and Asn167 were newly detected in this enzyme group. The substituted amino acids that might contribute to substrate binding were found at subsite B (Asn122Ser, Phe123Met). The amino acid sequences that formed three alpha-helices and three beta-sheets were completely conserved. The disulfide bond locations and catalytic amino acid were also strictly conserved. The conservation of the three alpha-helices structures and the location of disulfide bonds were considered to be important for the formation of the hydrophobic core structure of the catalytic site and for maintaining a similar three-dimensional structure in this enzyme group. PMID:11866097

  14. Structural trends in off stoichiometric chalcopyrite type compound semiconductors

    Energy supply is one of the most controversial topics that are currently discussed in our global community. Most of the energy delivered to the customer today has its origin in fossil and nuclear power plants. Indefinable risks and the radioactive waste repository problem of the latter as well as the global scarcity of fossil resources cause the renewable energies to grow more and more important for achieving sustainability. The main renewable energy sources are wind power, hydroelectric power and solar energy. On the photovoltaic (PV) market different materials are competing as part of different kinds of technologies, with the largest contribution still coming from wafer based crystalline silicon solar cells (95 %). Until now thin film solar cells only contribute a small portion to the whole PV market, but large capacities are under construction. Thin film photovoltaic shows a number of advantages in comparison to wafer based crystalline silicon PV. Among these material usage and production cost reduction are two prominent examples. The type of PV materials, which are analyzed in this work, are high potential compounds that are widely used as absorber layer in thin film solar cells. These are compound semiconductors of the type CuBIIICVI2 (BIII = In, Ga and CVI = Se, S). Several years of research have already gone into understanding the efficiency limiting factors for solar cell devices fabricated from this compound. Most of the studies concerning electronic defects are done by spectroscopic methods mostly performed using thin films from different kinds of synthesis, without any real knowledge regarding the structural origin of these defects. This work shows a systematic fundamental structural study of intrinsic point defects that are present within the material at various compositions in CuBIIICVI2 compound semiconductors. The study is done on reference powder samples with well determined chemical composition and using advanced diffraction techniques, such as neutron and synchrotron X-ray diffraction. The results show that the main existing defects are found to be copper vacancies and BIIICu anti-site defects. Type and concentrations vary with the composition. It is demonstrated that, when assuming spontaneous formation of electrically neutral defect complexes made of these isolated point defects, the density of cationic point defects is reduced by an order of magnitude. This explains why the existence of native cationic point defects may not be the main efficiency limiting factor in thin film solar cells built with a CuBIIICVI2 absorber. This pinpoints why the mere presence of native cationic point defects does probably not suffice as main efficiency limiting factor in thin film solar cells based on CuBIIICVI2-type absorbers.

  15. Gradient type optimization methods for electronic structure calculations

    Zhang, Xin; Wen, Zaiwen; Zhou, Aihui

    2013-01-01

    The density functional theory (DFT) in electronic structure calculations can be formulated as either a nonlinear eigenvalue or direct minimization problem. The most widely used approach for solving the former is the so-called self-consistent field (SCF) iteration. A common observation is that the convergence of SCF is not clear theoretically while approaches with convergence guarantee for solving the latter are often not competitive to SCF numerically. In this paper, we study gradient type methods for solving the direct minimization problem by constructing new iterations along the gradient on the Stiefel manifold. Global convergence (i.e., convergence to a stationary point from any initial solution) as well as local convergence rate follows from the standard theory for optimization on manifold directly. A major computational advantage is that the computation of linear eigenvalue problems is no longer needed. The main costs of our approaches arise from the assembling of the total energy functional and its grad...

  16. Electronic structure of p type Delta doped systems

    We summarize of the results obtained for the electronic structure of quantum wells that consist in an atomic layer doped with impurities of p type. The calculations are made within the frame worth of the wrapper function approach to independent bands and with potentials of Hartree. We study the cases reported experimentally (Be in GaAs and B in Si). We present the levels of energy, the wave functions and the rate of the electronic population between the different subbands, as well as the dependence of these magnitudes with the density of impurities in the layer. The participation of the bans of heavy holes is analysed, light and split-off band in the total electronic population. The effect of the temperature is discussed and we give a possible qualitative explanation of the experimental optical properties. (Author)

  17. Structure of the atmosphere of late-type stars

    A method of calculation of model atmospheres of late-type stars is described. The model atmospheres have been constructed for effective temperature Tsub(e)=2500, 3000, 3500, 4000, 4500 and 5785 K at solar chemical composition and surface gravities log g = 0.0, 1.0, 2.0, 3.0, 4.0 and 5.0 based on LTE and a plane-parallel horizontally homogeneous structure. Opacity due to H, H- and H2- was taken into account. The equation of state includes 10 metals and H2, H2- and H2+ molecules. The results are compared with those published elsewhere. A satisfactory agreement is obtained for Tsub(e) > 3000 K

  18. Reactor core lower structural members of PWR type reactor

    In the PWR type reactor of the present invention, a flow rate distribution of coolants in a lower plenum is unified, so that the reactor core is cooled uniformly as much as possible and fluid exciting vibration is reduced. Namely, the PWR type reactor has a large number of instrumentation guide tubes extending in parallel with each other between a semispherical shell-like bottom plate and a reactor core lower support plate of the reactor container. A connection support plate connects the instrumentation guide tubes so as to support them. The lower connection portion near the bottom plate of the reactor container is adapted to have a circular external shape, an annular region having no perforation hole is formed at the outer circumference thereof. It is disposed closer to the semispherical bottom plate thus constituting reactor lower structural members. With such a constitution, coolants flown down in an annular descending flow channel collide against the annular region having no perforation hole at the lower connection support plate, then form a uniform inward horizontal stream and join in a relatively wide region. As a result, uniform upwarding rate distribution can be obtained. Accordingly, local hot spots are not caused thereby enabling to operate the reactor efficiently. (I.S.)

  19. Perovskite-type oxides - Oxygen electrocatalysis and bulk structure

    Carbonio, R. E.; Fierro, C.; Tryk, D.; Scherson, D.; Yeager, E.

    1988-01-01

    Perovskite type oxides were considered for use as oxygen reduction and generation electrocatalysts in alkaline electrolytes. Perovskite stability and electrocatalytic activity are studied along with possible relationships of the latter with the bulk solid state properties. A series of compounds of the type LaFe(x)Ni1(-x)O3 was used as a model system to gain information on the possible relationships between surface catalytic activity and bulk structure. Hydrogen peroxide decomposition rate constants were measured for these compounds. Ex situ Mossbauer effect spectroscopy (MES), and magnetic susceptibility measurements were used to study the solid state properties. X ray photoelectron spectroscopy (XPS) was used to examine the surface. MES has indicated the presence of a paramagnetic to magnetically ordered phase transition for values of x between 0.4 and 0.5. A correlation was found between the values of the MES isomer shift and the catalytic activity for peroxide decomposition. Thus, the catalytic activity can be correlated to the d-electron density for the transition metal cations.

  20. Galaxy clusters, type Ia supernovae and the fine structure constant

    Holanda, R F L; Colaço, L R; Alcaniz, J S; Landau, S J

    2016-01-01

    As is well known, measurements of the Sunyaev-Zeldovich effect can be combined with observations of the X-ray surface brightness of galaxy clusters to estimate the angular diameter distance to these structures. In this paper, we show that this technique depends on the fine structure constant, $\\alpha$. Therefore, if $\\alpha$ is a time-dependent quantity, e.g., $\\alpha=\\alpha_0 \\phi(z)$, where $\\phi$ is a function of redshift, we argue that current data do not provide the real angular diameter distance, $D_{\\rm{A}}(z)$, to the cluster but instead $D_A^{data}(z) = \\phi(z)^2 D_{\\rm{A}}(z)$. We use this result to derive constraints on a possible variation of $\\alpha$ for a class of dilaton runaway models considering a sample of 25 measurements of $D_A^{data}(z)$ in redshift range $0.023 < z < 0.784$ and estimates of $D_{\\rm{A}}(z)$ from current type Ia supernovae observations. We find no significant indication of variation of $\\alpha$ with the present data.

  1. Type IIA orientifolds on SU(2)-structure manifolds

    Danckaert, Thomas

    2010-11-15

    We investigate the possible supersymmetry-preserving orientifold projections of type IIA string theory on a six-dimensional background with SU(2)-structure. We find two categories of projections which preserve half of the low-energy supersymmetry, reducing the effective theory from an N=4 supergravity theory, to an N=2 supergravity. For these two cases, we impose the projection on the low-energy spectrum and reduce the effective N=4 supergravity action accordingly. We can identify the resulting gauged N=2 supergravity theory and bring the action into canonical form. We compute the scalar moduli spaces and characterize the gauged symmetries in terms of the geometry of these moduli spaces. Due to their origin in N=4 supergravity, which is a highly constrained theory, the moduli spaces are of a very simple form. We find that, for suitable background manifolds, isometries in all scalar sectors can become gauged. The obtained gaugings share many features with those of N=2 supergravities obtained previously from other G-structure compactifications. (orig.)

  2. Magnetic Structure of Rapidly Rotating FK Comae-Type Coronae

    Cohen, O; Kashyap, V L; Korhonen, H; Elstner, D; Gombosi, T I

    2010-01-01

    We present a three-dimensional simulation of the corona of an FK Com-type rapidly rotating G giant using a magnetohydrodynamic model that was originally developed for the solar corona in order to capture the more realistic, non-potential coronal structure. We drive the simulation with surface maps for the radial magnetic field obtained from a stellar dynamo model of the FK Com system. This enables us to obtain the coronal structure for different field topologies representing different periods of time. We find that the corona of such an FK Com-like star, including the large scale coronal loops, is dominated by a strong toroidal component of the magnetic field. This is a result of part of the field being dragged by the radial outflow, while the other part remains attached to the rapidly rotating stellar surface. This tangling of the magnetic field,in addition to a reduction in the radial flow component, leads to a flattening of the gas density profile with distance in the inner part of the corona. The three-dim...

  3. Structure, Function, and Assembly of Type 1 Fimbriae

    Knight, Stefan D.; Bouckaert, Julie

    Bacterial infections constitute a major global health problem, acutely accentuated by the rapid spread of antibiotic resistant bacterial strains. The widespread need for bacteria to attach - adhere - to target cells before they can initiate an infection may be used to advantage by targeting the bacterial adhesion tools such as pili and fimbriae for development of novel anti-bacterial vaccines and drugs. Type 1 fimbriae are widely expressed by Escherichia coli. and are used by uropathogenic strains to mediate attachment to specific niches in the urinary tract. These fimbriae belong to a class of fibrillar adhesion organelles assembled through the chaperone/usher pathway, one of the terminal branches of the general secretion pathway in Gram-negative bacteria. Our understanding of the assembly, structure and function of these structures has evolved significantly over the last decade. Here, we summarize current understanding of the function and biogenesis of fibrillar adhesion organelles, and provide some examples of recent progress towards interfering with bacterial adhesion as a means to prevent infection.

  4. Structural phase transitions of rare earth monophosphides with NaCl-type structure under high pressures

    Rare earth monophosphides REP (RE=La, Ce, Pr, Nd, Sm, Gd, Tb, Tm and Yb) crystallize in a NaCl-type structure at ambient pressure. Using synchrotron radiation X-ray diffractions of REP have been studied up to about 60 GPa at room temperature. All phosphides are found to undergo structural phase transitions at high pressures. The high pressure phases of LaP, PrP and NdP can be assigned to be a tetragonal structure, which can be seen as the distorted CsCl-type structure. The pressure-induced phase transitions of SmP, GdP, TbP, TmP and YbP occur at around 35, 40, 38, 53 and 51 GPa, respectively. The structure of the high pressure phases is unknown. X-ray diffraction patterns of the compounds with many f-electrons become more complex at high pressure. It is expected that 4f-electrons in rare earth atoms influence the structure of the high pressure phases. (author)

  5. Structural controls of shihongtan sandstone-type uranium deposit in the southwestern turpan-hami basin

    Through studying the structural evolution, structural characteristics of Shihongtan sandstone-type uranium deposit, it is found that there are three types of structural controls on Shihongtan sandstone-type uranium deposit on the Aiding structural slope, namely, the uranium sources, types of the sedimentary formation of target horizons and the mineralization epochs are controlled by the structural evolution of the basin; the mineralization area are controlled by the structural slope units; the distribution of uranium ore bodies is controlled by the second order structures on the structural slope. (authors)

  6. Deformations of complex structures on Riemann surfaces and integrable structures in Whitham type hierarchies

    Odesskii, Alexander

    2015-01-01

    We obtain variational formulas for holomorphic objects on Riemann surfaces with respect to arbitrary local coordinates on moduli space of complex structures. These formulas are written in terms of a canonical object on moduli space which corresponds to the pairing between the space of quadratic differentials and the tangent space to moduli space. This canonical object satisfies certain commutation relations which appear to be the same as ones emerged in integrability theory of Whitham type hierarchies. Driven by this observation, we develop the theory of Whitham type hierarchies integrable by hydrodynamic reductions as a theory of certain differential-geometric objects.

  7. Structural trends in off stoichiometric chalcopyrite type compound semiconductors

    Stephan, Christiane

    2011-03-15

    Energy supply is one of the most controversial topics that are currently discussed in our global community. Most of the energy delivered to the customer today has its origin in fossil and nuclear power plants. Indefinable risks and the radioactive waste repository problem of the latter as well as the global scarcity of fossil resources cause the renewable energies to grow more and more important for achieving sustainability. The main renewable energy sources are wind power, hydroelectric power and solar energy. On the photovoltaic (PV) market different materials are competing as part of different kinds of technologies, with the largest contribution still coming from wafer based crystalline silicon solar cells (95 %). Until now thin film solar cells only contribute a small portion to the whole PV market, but large capacities are under construction. Thin film photovoltaic shows a number of advantages in comparison to wafer based crystalline silicon PV. Among these material usage and production cost reduction are two prominent examples. The type of PV materials, which are analyzed in this work, are high potential compounds that are widely used as absorber layer in thin film solar cells. These are compound semiconductors of the type CuB{sup III}C{sup VI}{sub 2} (B{sup III} = In, Ga and C{sup VI} = Se, S). Several years of research have already gone into understanding the efficiency limiting factors for solar cell devices fabricated from this compound. Most of the studies concerning electronic defects are done by spectroscopic methods mostly performed using thin films from different kinds of synthesis, without any real knowledge regarding the structural origin of these defects. This work shows a systematic fundamental structural study of intrinsic point defects that are present within the material at various compositions in CuB{sup III}C{sup VI}{sub 2} compound semiconductors. The study is done on reference powder samples with well determined chemical composition and using advanced diffraction techniques, such as neutron and synchrotron X-ray diffraction. The results show that the main existing defects are found to be copper vacancies and B{sup III}{sub Cu} anti-site defects. Type and concentrations vary with the composition. It is demonstrated that, when assuming spontaneous formation of electrically neutral defect complexes made of these isolated point defects, the density of cationic point defects is reduced by an order of magnitude. This explains why the existence of native cationic point defects may not be the main efficiency limiting factor in thin film solar cells built with a CuB{sup III}C{sup VI}{sub 2} absorber. This pinpoints why the mere presence of native cationic point defects does probably not suffice as main efficiency limiting factor in thin film solar cells based on CuB{sup III}C{sup VI}{sub 2}-type absorbers.

  8. Mass Structure of Axial Vector Types of Leptons and Fields

    Sharafiddinov, Rasulkhozha S

    2011-01-01

    A classification of currents with respect to C-operation admits the existence of C-noninvariant types of Dirac fermions. Among them one can meet an electroweakly charged C-antisymmetrical leptons, the mass of which includes the electric and weak components responsible for the existence of their anapole charge, charge radius and electric dipole moment. Such connections can constitute the paraleptons of axial-vector currents, for example, at the interactions with field of spinless nuclei of true neutrality. We derive the united equations which relate the structural parts of mass to anapole, charge radius and electric dipole of any truly neutral lepton in the framework of flavour symmetry. Thereby, they establish the C-odd nature of leptons and fields at the level of constancy law of the size implied from the multiplication of a weak mass of C-antisymmetrical lepton by its electric mass. Therefore, all leptons of C-antisymmetricality regardless of the difference in masses of an axial-vector character, have the s...

  9. Crystal structure of wild-type human procathepsin K.

    Sivaraman, J; Lalumire, M; Mnard, R; Cygler, M

    1999-02-01

    Cathepsin K is a lysosomal cysteine protease belonging to the papain superfamily. It has been implicated as a major mediator of osteoclastic bone resorption. Wild-type human procathepsin K has been crystallized in a glycosylated and a deglycosylated form. The latter crystals diffract better, to 3.2 A resolution, and contain four molecules in the asymmetric unit. The structure was solved by molecular replacement and refined to an R-factor of 0.194. The N-terminal fragment of the proregion forms a globular domain while the C-terminal segment is extended and shows substantial flexibility. The proregion interacts with the enzyme along the substrate binding groove and along the proregion binding loop (residues Ser138-Asn156). It binds to the active site in the opposite direction to that of natural substrates. The overall binding mode of the proregion to cathepsin K is similar to that observed in cathepsin L, caricain, and cathepsin B, but there are local differences that likely contribute to the specificity of these proregions for their cognate enzymes. The main observed difference is in the position of the short helix alpha3p (67p-75p), which occupies the S' subsites. As in the other proenzymes, the proregion utilizes the S2 subsite for anchoring by placing a leucine side chain there, according to the specificity of cathepsin K toward its substrate. PMID:10048321

  10. Synthesis, crystal structure and spectroscopy properties of Na 3AZr(PO 4) 3 ( A=Mg, Ni) and Li 2.6Na 0.4NiZr(PO 4) 3 phosphates

    Chakir, M.; El Jazouli, A.; de Waal, D.

    2006-06-01

    Na 3AZr(PO 4) 3 ( A=Mg, Ni) phosphates were prepared at 750 °C by coprecipitation route. Their crystal structures have been refined at room temperature from X-ray powder diffraction data using Rietveld method. Li 2.6Na 0.4NiZr(PO 4) 3 was synthesized through ion exchange from the sodium analog. These materials belong to the Nasicon-type structure. Raman spectra of Na 3AZr(PO 4) 3 ( A=Mg, Ni) phosphates present broad peaks in favor of the statistical distribution in the sites around PO 4 tetrahedra. Diffuse reflectance spectra indicate the presence of octahedrally coordinated Ni 2+ ions.

  11. Seismic verification methods for structures and equipment of VVER-type and RBMK-type NPPs (summary of experiences)

    The main verification methods for structures and equipment of already existing VVER-type and RBMK-type NPPs are briefly described. The following aspects are discussed: fundamental seismic safety assessment principles for VVER/RBMK-type NPPs (seismic safety assessment procedure, typical work plan for seismic safety assessment of existing NPPs, SMA (HCLPF) calculations, modified GIP (GIP-VVER) procedure, similarity of VVER/RBMK equipment to that included in the SQUG databases and seismic interactions

  12. Synthesis and characterization of a NaSICON series with general formula Na2.8Zr2-ySi1.8-4yP1.2+4yO12 (0=

    In this work, we present the synthesis and the characterization of ionic conducting ceramics of NaSICON-type (Natrium super ionic conductor). The properties of this ceramic make it suitable for use in electrochemical devices. These solid electrolytes can be used as sensors for application in the manufacturing of potentiometric gas sensors, for the detection of pollutant emissions and for environment control. The family of NaSICON that we studied has as a general formula Na2.8Zr2-ySi1.8-4yP1.2+4yO12 with 0=2.8Zr1.775Si0.9P2.1O12 composition

  13. Synthesis and characterization of a NaSICON series with general formula Na 2.8Zr 2-ySi 1.8-4yP 1.2+4yO 12 (0⩽ y⩽0.45)

    Essoumhi, A.; Favotto, C.; Mansori, M.; Satre, P.

    2004-12-01

    In this work, we present the synthesis and the characterization of ionic conducting ceramics of NaSICON-type (Natrium super ionic conductor). The properties of this ceramic make it suitable for use in electrochemical devices. These solid electrolytes can be used as sensors for application in the manufacturing of potentiometric gas sensors, for the detection of pollutant emissions and for environment control. The family of NaSICON that we studied has as a general formula Na 2.8Zr 2-ySi 1.8-4yP 1.2+4yO 12 with 0⩽ y⩽0.45. The various compositions were synthesized by produced using the sol-gel method. The electric properties of these compositions were carried out by impedance spectroscopy. The results highlight the good conductivity of the Na 2.8Zr 1.775Si 0.9P 2.1O 12 composition.

  14. The prolongation structure of the inhomogeneous equation of the reaction-diffusion type

    The inhomogeneous extension of equations of the reaction-diffusion type is investigated by means of the covariant prolongation structures theory. We construct the sl(2, R) x R(ρ(t)) prolongation structure for an inhomogeneous equation of the reaction-diffusion type and give the corresponding AKNS-type equations and the Baecklund transformation

  15. Hamiltonian structure of Kadomtsev-Petviashvill: type equations

    A description of Hamiltonian structure and of the integrals of motion is given, in a general group-theoretic setting, for nonlinear equations with two space variables. The connections with a nonlocal Riemann problem, the multitime formalism, and the Hamiltonian structure of stationary problems are discussed

  16. A New Type of Center Data Structure in Cloud Computing

    Guo Xiaohui

    2014-01-01

    Full Text Available This study analyzes and summarizes new characteristics of Cloud Computing data center, a new network structure in the design of cloud computing data center is proposed, the concepts of Cloud Computing and data center are introduced. It analyzes three important issues deeply, the scalability and green energy issues of the data center are analyzed and it makes full consideration of new characteristics of Cloud Computing data center and presents a new data center network structure according to famous Koch Curve, the snow structure. It makes full account of the data centers scalability and low proportion of switches and servers and can achieve routing within a shorter average path and smaller network overhead. In the study of snowflake structure of cloud computing data center network building methods are proposed and its properties are discussed, the simulation and experiments are performed to validate the performance of the structure.

  17. A New Type of Center Data Structure in Cloud Computing

    Guo Xiaohui; Wei Jian Yu; Wang Beibei; Liyongqing

    2014-01-01

    This study analyzes and summarizes new characteristics of Cloud Computing data center, a new network structure in the design of cloud computing data center is proposed, the concepts of Cloud Computing and data center are introduced. It analyzes three important issues deeply, the scalability and green energy issues of the data center are analyzed and it makes full consideration of new characteristics of Cloud Computing data center and presents a new data center network structure according to f...

  18. Soil/structure interactions of eastern US type earthquakes

    This paper presents analyses and conclusions pertaining to the earthquake motions felt at Virgil C. Summer, Perry and Krsko nuclear power plants. Consideration is given to promote an improved understanding of these events, describe common characteristics, assess damage potential, and recommend operating procedures for similar future events. An easy-to-follow analytical investigation is performed to describe how the earthquakes recorded at Krsko may be influenced by soil/structure interaction including a few parametric studies to account for uncertainties in the soil properties. These consist of variations in the shear and compressional wave velocities and variations in the seismic wave environment in the form of arbitrarily oriented body waves or Rayleigh waves. The analysis takes into account nonlinearity of the soil material, radiation and hysteretic damping, ground-water table level, structural embedment, and structure/structure interaction. The analysis is based on state-of-the-art computer software, elaborate analysis techniques and simpler engineering approximations. Results of analysis show clear evidence of soil/structure interaction, nonlinear softening of the soil material and encouraging qualitative and quantitative agreement with the recorded measurements. The structural response motions display high rocking mode

  19. A Quasi-Type-1 Phase-Locked Loop Structure

    Golestan, Saeed; Fernandez, Francisco Daniel Freijedo; Vidal, Ana; Guerrero, Josep M.; Doval-Gandoy, Jesus

    2014-01-01

    The grid voltage phase and frequency are crucial information in control of most grid connected power electronic based equipment. Most often, a phase-locked loop (PLL) is employed for this purpose. A PLL is a closed-loop feedback control system that the phase of its output signal is related to the...... point of view is a type-2 control system. For this reason, it is called the quasi-type-1 PLL (QT1-PLL). The effectiveness of the proposed PLL is confirmed through simulation and experimental results and comparison with standard PLLs....

  20. Structures of the Mating-Type Loci of Cordyceps takaomontana

    Yokoyama, Eiji; Yamagishi, Kenzo; HARA, AKIRA

    2003-01-01

    Nucleotide sequences of the mating-type loci MAT1-1 and MAT1-2 of Cordyceps takaomontana were determined, which is the first such report for the clavicipitaceous fungi. MAT1-1 contains two mating-type genes, MAT1-1-1 and MAT1-1-2, but MAT1-1-3 could not be found. On the other hand, MAT1-2 has MAT1-2-1. A pseudogene of MAT1-1-1 is located next to MAT1-2.

  1. A Quasi-Type-1 Phase-Locked Loop Structure

    Golestan, Saeed; Fernandez, Francisco Daniel Freijedo; Vidal, Ana; Guerrero, Josep M.; Doval-Gandoy, Jesus

    2014-01-01

    The grid voltage phase and frequency are crucial information in control of most grid connected power electronic based equipment. Most often, a phase-locked loop (PLL) is employed for this purpose. A PLL is a closed-loop feedbackcontrol system that the phase of its output signal is related to the phase of its input signal. Arguably, the simplest PLL is a type-1 PLL. The type-1 PLLs are characterized by having only one integrator in their control loop and therefore having a high stability margi...

  2. Study on lithium/air secondary batteries - Stability of NASICON-type lithium ion conducting glass-ceramics with water

    Hasegawa, Satoshi; Imanishi, Nobuyuki; Zhang, Tao; Xie, Jian; Hirano, Atsushi; Takeda, Yasuo; Yamamoto, Osamu [Department of Chemistry, Faculty of Engineering, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507 (Japan)

    2009-04-01

    The water stability of the fast lithium ion conducting glass-ceramic electrolyte, Li{sub 1+x+y}Al{sub x}Ti{sub 2-x}Si{sub y}P{sub 3-y}O{sub 12} (LATP), has been examined in distilled water, and aqueous solutions of LiNO{sub 3}, LiCl, LiOH, and HCl. This glass-ceramics are stable in aqueous LiNO{sub 3} and aqueous LiCl, and unstable in aqueous 0.1 M HCl and 1 M LiOH. In distilled water, the electrical conductivity slightly increases as a function of immersion time in water. The Li-Al/Li{sub 3-x}PO{sub 4-y}N{sub y}/LATP/aqueous 1 M LiCl/Pt cell, where lithium phosphors oxynitrides Li{sub 3-x}PO{sub 4-y}N{sub y} (LiPON) are used to protect the direct reaction of Li and LATP, shows a stable open circuit voltage (OCV) of 3.64 V at 25 C, and no cell resistance change for 1 week. Lithium phosphors oxynitride is effectively used as a protective layer to suppress the reaction between the LATP and Li metal. The water-stable Li/LiPON/LATP system can be used in Li/air secondary batteries with the air electrode containing water. (author)

  3. Electrochemical properties of Li symmetric solid-state cell with NASICON-type solid electrolyte and electrodes

    Kobayashi, Eiji; Plashnitsa, Larisa S.; Doi, Takayuki; Okada, Shigeto; Yamaki, Jun-ichi [Institute for Materials Chemistry and Engineering, Kyushu University, Kasuga Koen 6-1, Kasuga-shi, Fukuoka 816-8580 (Japan)

    2010-07-15

    All-solid-state phosphate symmetric cells using Li{sub 3}V{sub 2}(PO{sub 4}){sub 3} for both the positive and negative electrodes with the phosphate Li{sub 1.5}Al{sub 0.5}Ge{sub 1.5}(PO{sub 4}){sub 3} as the solid electrolyte were proposed. Amorphous Li{sub 1.5}Al{sub 0.5}Ge{sub 1.5}(PO{sub 4}){sub 3} was added into the electrode to increase the interface area between the active materials and the electrolyte. Any other phases were not formed at the electrode/electrolyte interface even after hot pressing at 600 C. The discharge capacity was 92 mAh g{sup -} {sup 1} at 22 {mu}A cm{sup -} {sup 2} at 80 C, and 38 mAh g{sup -} {sup 1} at 25 C, respectively. Symmetric cell configuration leads to simplify the fabrication process for all-solid-state batteries and will reduce manufacturing costs. (author)

  4. Well-formedness and typing rules for UML Composite Structures

    Dragomir, Iulia

    2010-01-01

    Starting from version 2.0, UML introduced hierarchical composite structures, which are an expressive way of defining complex software architectures, but which have a very loosely defined semantics in the standard. In this paper we propose a set of consistency rules that disambiguate the meaning of UML composite structures. Our primary goal was to have an operational model of composite structures for the OMEGA UML profile, an executable profile dedicated to the formal specification and validation of real-time systems, developed in a past project to which we contributed. However, the rules and principles stated here are applicable to other hierarchical component models based on the same concepts, such as SysML. The presented ruleset is supported by an OCL formalization which is described in this report. This formalization was applied on different complex models for the evaluation and validation of the proposed principles.

  5. On Tanaka's Prolongation Procedure for Filtered Structures of Constant Type

    Igor Zelenko

    2009-10-01

    Full Text Available We present Tanaka's prolongation procedure for filtered structures on manifolds discovered in [Tanaka N., J. Math. Kyoto. Univ. 10 (1970, 1-82] in a spirit of Singer-Sternberg's description of the prolongation of usual G-structures [Singer I.M., Sternberg S., J. Analyse Math. 15 (1965, 1-114; Sternberg S., Prentice-Hall, Inc., Englewood Cliffs, N.J., 1964]. This approach gives a transparent point of view on the Tanaka constructions avoiding many technicalities of the original Tanaka paper.

  6. Preparación cristaloquímica y comportamiento eléctrico de electrolitos sólidos de estequiometría NASICON

    Maldonado Manso, María Pilar

    2004-01-01

    En el presente trabajo se ha llevado a cabo la preparación y la caracterización estructural y eléctrica de varias series de materiales de estequiometría NASICON, sistema ampliamente conocido por sus propiedades conductoras y adecuadas prestaciones en el campo de los electrolitos sólidos. Las síntesis se han realizado, en general, en estado sólido por el método cerámico, caracterizándose los compuestos obtenidos empleando muy diversas técnicas como difracción de rayos-X y/o neut...

  7. Structures in the fundamental plane of early-type galaxies

    Fraix-Burnet, Didier; Chattopadhyay, Tanuka; Chattopadhyay, Asis Kumar; Davoust, Emmanuel

    2010-01-01

    The fundamental plane of early-type galaxies is a rather tight three-parameter correlation discovered more than twenty years ago. It has resisted a both global and precise physical interpretation despite a consequent number of works, observational, theoretical or using numerical simulations. It appears that its precise properties depend on the population of galaxies in study. Instead of selecting a priori these populations, we propose to objectively construct homologous populations from multivariate analyses. We have undertaken multivariate cluster and cladistic analyses of a sample of 56 low-redshift galaxy clusters containing 699 early-type galaxies, using four parameters: effective radius, velocity dispersion, surface brightness averaged over effective radius, and Mg2 index. All our analyses are consistent with seven groups that define separate regions on the global fundamental plane, not across its thickness. In fact, each group shows its own fundamental plane, which is more loosely defined for less diver...

  8. On the structures of magnetic flux rope type

    The analysis of observation results of structures like magnetic flux ropes in the magnetotail carried out by the satellite Prognoz-9 is presented. The rope magnetic perturbation data are compared to the magnetic field characteristics in the interplanetary medium and near the bow shock wave front. 4 refs.; 4 figs

  9. A New Type Method for the Structured Variational Inequalities Problem

    Chengjiang Yin

    2013-01-01

    In this paper, we present an algorithm for solving the structured variational inequality problem, and prove the global convergence of the new method without carrying out any line search technique, and the global R-convergence rate are also given under the suitable conditions.

  10. Structural and dielectric properties of perovskite-type artificial superlattices

    BaTiO3/SrTiO3, SrZrO3/SrTiO3 and BaTiO3/BaZrO3 artificial superlattices were fabricated by the molecular beam epitaxy process. X-ray diffraction (XRD) reciprocal space mapping measurement was performed using high-resolution XRD. In all artificial superlattices, the superlattices with the 10-periodic structure showed the clear satellite peaks in the XRD pattern and were mostly distorted in the direction of film thickness. Superlattices with the 10-periodic structure showed a high dielectric permittivity of ? r = 33,000 or artificially induced ferroelectricity. It was clarified that the anisotropic lattice distortion introduced by the strains due to the lattice mismatch was the origin of the unique dielectric characteristics of artificial superlattices

  11. New actinide-loaded matrices with pyrochlore-type structure

    New crystal actinide-loaded matrices with pyrochlore structure containing actinides, rare earths and zirconium, were studied by the methods of X-ray phase analysis, scanning and transmission electron microscopy. Special; attention was paid to compounds with ideal stoichiometry: VIII(CaA4+)VI(B4+)2O7, where A4+ = Ce, Th or U, B4+ = Ti or/and Zr, which are of considerable interest for high-level waste fixation. It is shown that sizes of octahedral ions in pyrochlore lattice for rare earth and trivalent actinide phases may vary from 0.055 to 0.075 nm. Ions of Ti4+, Sn4+, Hf4+ and Zr4+ meet the condition. Tetravalent actinides will fill octa-coordinated structural positions in case of conjugated inclusion of Ca2+ cations

  12. A Type-Theoretic Approach to Structural Resolution

    Fu, Peng; Komendantskaya, Ekaterina

    2015-01-01

    Structural resolution (or S-resolution) is a newly proposed alternative to SLD-resolution that allows a systematic separation of derivations into term-matching and unification steps. Productive logic programs are those for which term-matching reduction on any query must terminate. For productive programs with coinductive meaning, finite term-rewriting reductions can be seen as measures of observation in an infinite derivation. Ability of handling corecursion in a productive way is an attracti...

  13. Categorizing the Types of Surfing Breaks around Jetty Structures

    Scarfe, B. E.; Elwany, M. H.S.; Black, K. P.; Mead, S. T.

    2003-01-01

    Coastal modifications to control erosion, maintain navigation channels, and create harbors are often undertaken near surfing breaks. Surfing conditions can be improved by these activities, but they can also adversely affect existing surfing breaks. Jetties are coastal structures that on occasion improve surfing conditions. Even though there is an increasing volume of literature on the ways ordinary waves transform into surfing waves, the mechanics of surfing breaks around jetties has not been...

  14. Fine-structure constant constraints on Bekenstein-type models

    Leal, P. M. M.; Martins, C.J.A.P.; Ventura, L. B.

    2014-01-01

    Astrophysical tests of the stability of dimensionless fundamental couplings, such as the fine-structure constant $\\alpha$, are an area of much increased recent activity, following some indications of possible spacetime variations at the few parts per million level. Here we obtain updated constraints on the Bekenstein-Sandvik-Barrow-Magueijo model, which is arguably the simplest model allowing for $\\alpha$ variations. Recent accurate spectroscopic measurements allow us to improve previous cons...

  15. Type of disturbance and ecological history determine structural stability

    Wurff, van der, R.; Kools, S.A.E.; Boivin, M. E. Y.; Brink, van den, W.; Megen, van, H.J.G.M.; Riksen, J. A. G.; Doroszuk, A.; Kammenga, J E

    2007-01-01

    This study aims to reveal whether complexity, namely, community and trophic structure, of chronically stressed soil systems is at increased risk or remains stable when confronted with a subsequent disturbance. Therefore, we focused on a grassland with a history of four centuries of patchy contamination. Nematodes were used as model organisms because they are an abundant and trophically diverse group and representative of the soil food web and ecosystem complexity. In a field survey, a relatio...

  16. The structural stability of wild-type horse prion protein.

    Zhang, Jiapu

    2011-10-01

    Prion diseases (e.g. Creutzfeldt-Jakob disease (CJD), variant CJD (vCJD), Gerstmann-Straussler-Scheinker syndrome (GSS), Fatal Familial Insomnia (FFI) and Kuru in humans, scrapie in sheep, bovine spongiform encephalopathy (BSE or 'mad-cow' disease) and chronic wasting disease (CWD) in cattles) are invariably fatal and highly infectious neurodegenerative diseases affecting humans and animals. However, by now there have not been some effective therapeutic approaches or medications to treat all these prion diseases. Rabbits, dogs, and horses are the only mammalian species reported to be resistant to infection from prion diseases isolated from other species. Recently, the β2-α2 loop has been reported to contribute to their protein structural stabilities. The author has found that rabbit prion protein has a strong salt bridge ASP177-ARG163 (like a taut bow string) keeping this loop linked. This paper confirms that this salt bridge also contributes to the structural stability of horse prion protein. Thus, the region of β2-α2 loop might be a potential drug target region. Besides this very important salt bridge, other four important salt bridges GLU196-ARG156-HIS187, ARG156-ASP202 and GLU211-HIS177 are also found to greatly contribute to the structural stability of horse prion protein. Rich databases of salt bridges, hydrogen bonds and hydrophobic contacts for horse prion protein can be found in this paper. PMID:21875155

  17. Structure of a class of Lie algebras of Block type

    Xia, Chunguang; You, Taijie; Zhou, Liji

    2011-01-01

    Let $\\BB$ be a class of Lie algebras of Block type with basis $\\{L_{\\a,i}|\\a,i\\in\\Z, i\\geq 0\\}$ and relations $[L_{\\a,i},L_{\\b,j}]=(\\b(i+q)-\\a(j+q))L_{\\a+\\b,i+j}$, where $q$ is a positive integer. In this paper, it is shown that $\\BB$ are different from each other for distinct positive integers $q$'s. The automorphism groups, the derivation algebras and the central extensions of all $\\BB$ are also uniformly and explicitly described, which generalize some previous results.

  18. Profiling of N-Type Dopants in Silicon Based Structures

    Hovorka, Miloš; Mika, Filip; Frank, Luděk; Mikulík, P.

    Brno : ISI AS CR, 2009 - (Pokorná, Z.; Mika, F.), s. 14 ISBN 978-80-254-4535-8. [CJCS’09 - Czech-Japan-China Cooperative Symposium on Nanostructure of Advanced Materials and Nanotechnology /4./. Brno (CZ), 10.08.2009-14.08.2009] R&D Projects: GA ČR GP102/09/P543; GA AV ČR IAA100650803 Institutional research plan: CEZ:AV0Z20650511 Keywords : n-type substrate * SEM * PEEM * doping levels Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  19. Atlas of fine structures of dynamic spectra of solar type IV-dm and some type II radio bursts

    The author presents an atlas of spectral fine structures of solar radio bursts of types IV and II around 1 m wavelength, as obtained with a multichannel spectrograph at Dwingeloo. The structures form largely a collection of observations of these events during late 1968 through 1974, thus covering almost entirely the declining branch of solar cycle 20. The spectrograph has an extra enhanced contrast output with properties quite different from those of the commonly used swept frequency spectrographs. The corresponding instrumental characteristics and effects are discussed. A classification of fine structures and an analysis of their statistical properties and of those of the pertinent radio events are also given. (Auth.)

  20. Fine-structure constant constraints on Bekenstein-type models

    Leal, P. M. M.; Martins, C. J. A. P.; Ventura, L. B.

    2014-07-01

    Astrophysical tests of the stability of dimensionless fundamental couplings, such as the fine-structure constant α, are an area of much increased recent activity, following some indications of possible spacetime variations at the few parts per million level. Here we obtain updated constraints on the Bekenstein-Sandvik-Barrow-Magueijo model, which is arguably the simplest model allowing for α variations. Recent accurate spectroscopic measurements allow us to improve previous constraints by about an order of magnitude. We briefly comment on the dependence of the results on the data sample, as well as on the improvements expected from future facilities.

  1. Structural constraints on human immunodeficiency virus type 1 Nef function

    HIV-1 Nef is a multifunctional protein that exerts its activities through interactions with multiple cellular partners. Nef uses different domains and mechanisms to exert its functions including cell surface down-modulation of CD4 and MHC-I receptors and activation of the serine/threonine kinase PAK-2. We inserted tags at the C-terminus and proximal to the N-terminus of Nef and the effects on Nef's structure/function relationships were examined. We discovered significant defects in MHC-I down-modulation with the insertion of HA/FLAG tags at either region. We also found impaired PAK-2 activation with a C-terminal fusion with GFP. Interestingly, Nef-GFP and Nef-GH7 induced MHC-I down-modulation, suggesting that the negative charge of the HA/FLAG tag could contribute to the observed defect. Together, these observations highlight elements of Nef's functional complexity and demonstrate previously unsuspected structural requirements for PAK-2 activation and MHC-1 down-modulation in Nef's flexible N- and C-terminal regions

  2. Structural Analysis of Botulinum Neurotoxin Type G Receptor Binding

    Schmitt, John; Karalewitz, Andrew; Benefield, Desire A.; Mushrush, Darren J.; Pruitt, Rory N.; Spiller, Benjamin W.; Barbieri, Joseph T.; Lacy, D. Borden (Vanderbilt); (MCW)

    2010-10-19

    Botulinum neurotoxin (BoNT) binds peripheral neurons at the neuromuscular junction through a dual-receptor mechanism that includes interactions with ganglioside and protein receptors. The receptor identities vary depending on BoNT serotype (A-G). BoNT/B and BoNT/G bind the luminal domains of synaptotagmin I and II, homologous synaptic vesicle proteins. We observe conditions under which BoNT/B binds both Syt isoforms, but BoNT/G binds only SytI. Both serotypes bind ganglioside G{sub T1b}. The BoNT/G receptor-binding domain crystal structure provides a context for examining these binding interactions and a platform for understanding the physiological relevance of different Syt receptor isoforms in vivo.

  3. Types of Planning Structures of Small Historic Towns of Ukraine

    Ievgeniia Zapunna

    2015-05-01

    Full Text Available The present article exhibits the results of systematic analysis on structure and planning of fragments of urban environment. The results have been obtained by looking into the prerequisites of formation of urban environment, specifically the impact of the Magdeburg Rights on urban culture. The study covers the small towns in Ukraine, which retained their historical background to a greater extent. 70 towns in Ukraine that had the Magdeburg Law have been analyzed and their historic, architectural and planning capacity investigated. The most valuable urban fragments have been classified in accordance with a number of criteria, such as the form of the plan, planning composition, etc. Based on the conducted analysis the author presents further generalized proposals for comprehensive development of historical and architectural heritage within the socio-cultural and tourism infrastructure of the Ukrainian towns.

  4. Effect of heat treatment conditions on the structure and mechanical properties of DP-type steel

    J. Adamczyk; A. Grajcar

    2006-01-01

    Purpose: The aim of the paper is to determine the influence of the initial structure and heat treatment conditions on mechanical properties of DP-type steel.Design/methodology/approach: The heat treatment of the low-carbon steel in order to obtain a DP-type structure of desirable ferrite and martensite fractions was realized. In order to investigate the structure light and transmission electron microscopy methods were used. Mechanical properties were determined by means of tensile test.Find...

  5. Vertical and Horizontal Vegetation Structure across Natural and Modified Habitat Types at Mount Kilimanjaro

    Rutten, Gemma; Ensslin, Andreas; Hemp, Andreas; Fischer, Markus

    2015-01-01

    In most habitats, vegetation provides the main structure of the environment. This complexity can facilitate biodiversity and ecosystem services. Therefore, measures of vegetation structure can serve as indicators in ecosystem management. However, many structural measures are laborious and require expert knowledge. Here, we used consistent and convenient measures to assess vegetation structure over an exceptionally broad elevation gradient of 8664550m above sea level at Mount Kilimanjaro, Tanzania. Additionally, we compared (human)-modified habitats, including maize fields, traditionally managed home gardens, grasslands, commercial coffee farms and logged and burned forests with natural habitats along this elevation gradient. We distinguished vertical and horizontal vegetation structure to account for habitat complexity and heterogeneity. Vertical vegetation structure (assessed as number, width and density of vegetation layers, maximum canopy height, leaf area index and vegetation cover) displayed a unimodal elevation pattern, peaking at intermediate elevations in montane forests, whereas horizontal structure (assessed as coefficient of variation of number, width and density of vegetation layers, maximum canopy height, leaf area index and vegetation cover) was lowest at intermediate altitudes. Overall, vertical structure was consistently lower in modified than in natural habitat types, whereas horizontal structure was inconsistently different in modified than in natural habitat types, depending on the specific structural measure and habitat type. Our study shows how vertical and horizontal vegetation structure can be assessed efficiently in various habitat types in tropical mountain regions, and we suggest to apply this as a tool for informing future biodiversity and ecosystem service studies. PMID:26406985

  6. Vertical and Horizontal Vegetation Structure across Natural and Modified Habitat Types at Mount Kilimanjaro.

    Rutten, Gemma; Ensslin, Andreas; Hemp, Andreas; Fischer, Markus

    2015-01-01

    In most habitats, vegetation provides the main structure of the environment. This complexity can facilitate biodiversity and ecosystem services. Therefore, measures of vegetation structure can serve as indicators in ecosystem management. However, many structural measures are laborious and require expert knowledge. Here, we used consistent and convenient measures to assess vegetation structure over an exceptionally broad elevation gradient of 866-4550 m above sea level at Mount Kilimanjaro, Tanzania. Additionally, we compared (human)-modified habitats, including maize fields, traditionally managed home gardens, grasslands, commercial coffee farms and logged and burned forests with natural habitats along this elevation gradient. We distinguished vertical and horizontal vegetation structure to account for habitat complexity and heterogeneity. Vertical vegetation structure (assessed as number, width and density of vegetation layers, maximum canopy height, leaf area index and vegetation cover) displayed a unimodal elevation pattern, peaking at intermediate elevations in montane forests, whereas horizontal structure (assessed as coefficient of variation of number, width and density of vegetation layers, maximum canopy height, leaf area index and vegetation cover) was lowest at intermediate altitudes. Overall, vertical structure was consistently lower in modified than in natural habitat types, whereas horizontal structure was inconsistently different in modified than in natural habitat types, depending on the specific structural measure and habitat type. Our study shows how vertical and horizontal vegetation structure can be assessed efficiently in various habitat types in tropical mountain regions, and we suggest to apply this as a tool for informing future biodiversity and ecosystem service studies. PMID:26406985

  7. The structure of the follistatin:activin complex reveals antagonism of both type I and type II receptor binding

    Thompson, T.B.; Lerch, T.F.; Cook, R.W.; Woodruff, T.K.; Jardetzky, T.S. (NWU)

    2010-03-08

    TGF-{beta} ligands stimulate diverse cellular differentiation and growth responses by signaling through type I and II receptors. Ligand antagonists, such as follistatin, block signaling and are essential regulators of physiological responses. Here we report the structure of activin A, a TGF-{beta} ligand, bound to the high-affinity antagonist follistatin. Two follistatin molecules encircle activin, neutralizing the ligand by burying one-third of its residues and its receptor binding sites. Previous studies have suggested that type I receptor binding would not be blocked by follistatin, but the crystal structure reveals that the follistatin N-terminal domain has an unexpected fold that mimics a universal type I receptor motif and occupies this receptor binding site. The formation of follistatin:BMP:type I receptor complexes can be explained by the stoichiometric and geometric arrangement of the activin:follistatin complex. The mode of ligand binding by follistatin has important implications for its ability to neutralize homo- and heterodimeric ligands of this growth factor family.

  8. Photovoltaic properties of ZnO nanorods/p-type Si heterojunction structures

    Rafal Pietruszka

    2014-02-01

    Full Text Available Selected properties of photovoltaic (PV structures based on n-type zinc oxide nanorods grown by a low temperature hydrothermal method on p-type silicon substrates (100 are investigated. PV structures were covered with thin films of Al doped ZnO grown by atomic layer deposition acting as transparent electrodes. The investigated PV structures differ in terms of the shapes and densities of their nanorods. The best response is observed for the structure containing closely-spaced nanorods, which show light conversion efficiency of 3.6%.

  9. On the number of type change loci of a generalized complex structure

    Torres, Rafael; Yazinski, Jonathan

    2013-01-01

    In this note, we describe a procedure to construct generalized complex structures with an arbitrarily large number of type change loci on products of the circle with a connected sum of closed 3-manifolds. The loci need not be isotopic.

  10. Structural and Mechanical Properties of Klebsiella pneumoniae Type 3 Fimbriae▿ §

    Chen, Feng-Jung; Chan, Chia-Han; Huang, Ying-Jung; Liu, Kuo-Liang; Peng, Hwei-Ling; Chang, Hwan-You; Liou, Gunn-Guang; Yew, Tri-Rung; Liu, Cheng-Hsien; Hsu, Ken Y.; Hsu, Long

    2011-01-01

    This study investigated the structural and mechanical properties of Klebsiella pneumoniae type 3 fimbriae, which constitute a known virulence factor for the bacterium. Transmission electron microscopy and optical tweezers were used to understand the ability of the bacterium to survive flushes. An individual K. pneumoniae type 3 fimbria exhibited a helix-like structure with a pitch of 4.1 nm and a three-phase force-extension curve. The fimbria was first nonlinearly stretched with increasing fo...

  11. Structural investigation of Eu 2+ emissions from alkaline earth zirconium phosphate

    Hirayama, Masaaki; Sonoyama, Noriyuki; Yamada, Atsuo; Kanno, Ryoji

    2009-04-01

    Eu 2+ doped A0.5Zr 2(PO 4) 3 ( A=Ca, Sr, Ba) phosphors with the NASICON structure were synthesized by a co-precipitation method. Their photoluminescent and structural properties were investigated by photoluminescent spectroscopy and powder X-ray Rietveld analysis, which determined two sites for Eu 2+ ions in the host structure, 3 a and 3 b. The Eu-O bond lengths were increased by changing alkaline earth ions from Ca to Ba, causing Eu 2+ emission bands to shift from blue-green to blue. A correlation was observed between the peak wavelength positions and the Eu-O bond length. The photoluminescent properties are discussed in terms of crystal field strength and nephelauxetic effect, and a schematic diagram of Eu 2+ emissions is proposed for the Eu 2+ doped NASICON phosphor.

  12. Imma perovskite-type oxynitride LaTiO2N: structure and electron density.

    Yashima, Masatomo; Saito, Mio; Nakano, Hiromi; Takata, Tsuyoshi; Ogisu, Kiyonori; Domen, Kazunari

    2010-07-14

    We present the first example of Imma perovskite-type oxynitride. LaTiO(2)N was found to have an Imma perovskite-type structure with a(0)b(-)b(-) tilt system. The Ti-(O,N) covalent bonding and existence of N atoms are responsible for the reduced band gap of LaTiO(2)N photocatalyst. PMID:20485779

  13. The structure of galaxies : the division of stellar mass by morphological type and structural component

    Kelvin, Lee Steven

    2013-01-01

    The mechanisms which cause galaxies to form and evolve each leave behind distinct structural markers in their wake. Dynamically hot processes (e.g., monolithic collapse, hierarchical merging) give rise to pressure-supported spheroidal structures, including elliptical galaxies and classical bulges. By contrast, dynamically cold processes (e.g., gas accretion, AGN splashback) lead to flattened rotationally-supported disk-like structures, often found on their own or as part of a spiral galaxy. I...

  14. Using a conceptual framework during learning attenuates the loss of expert-type knowledge structure

    Wilcox Elizabeth

    2006-07-01

    Full Text Available Abstract Background During evolution from novice to expert, knowledge structure develops into an abridged network organized around pathophysiological concepts. The objectives of this study were to examine the change in knowledge structure in medical students in one year and to investigate the association between the use of a conceptual framework (diagnostic scheme and long-term knowledge structure. Methods Medical students' knowledge structure of metabolic alkalosis was studied after instruction and one year later using concept-sorting. Knowledge structure was labeled 'expert-type' if students shared ? 2 concepts with experts and 'novice-type' if they shared Results Thirty-four medical students completed the concept-sorting task on both occasions. Twenty-four used a diagnostic scheme for metabolic alkalosis. Short-term knowledge structure was not a correlate of long-term knowledge structure, whereas use of a diagnostic scheme was associated with increased odds of expert-type long-term knowledge structure (odds ratio 12.6 [1.4, 116.0], p = 0.02. There was an interaction between short-term knowledge structure and the use of a diagnostic scheme. In the group who did not use a diagnostic scheme the number of students changing from expert-type to novice-type was greater than vice versa (p = 0.046. There was no significant change in the group that used the diagnostic scheme (p = 0.6. Conclusion The use of a diagnostic scheme by students may attenuate the loss of expert-type knowledge structure.

  15. The N=4 effective action of type IIA supergravity compactified on SU(2)-structure manifolds

    Danckaert, Thomas; Martínez-Pedrera, Danny; Spanjaard, Bastiaan; Triendl, Hagen

    2011-01-01

    We study compactifications of type IIA supergravity on six-dimensional manifolds with SU(2) structure and compute the low-energy effective action in terms of the non-trivial intrinsic torsion. The consistency with gauged N=4 supergravity is established and the gauge group is determined. Depending on the structure of the intrinsic torsion, antisymmetric tensor fields can become massive.

  16. Dowel-type fastener connections in timber structures subjected to short-term loading

    Lauritzen Jensen, J.

    Design of dowel-type fastener connections in framed timber structures usually involves a two-step analysis: determination of the distribution of the sectional forces, and design of the eccentrically loaded connections. This report presents an integrated model for design of framed timber structures...

  17. Influence of solvent type on structure, mechanical and thermal properties of fullerene containing films of polyethylene

    This article is devoted to influence of solvent type on structure, mechanical and thermal properties of fullerene containing films of polyethylene. The structure, mechanical and thermal properties of fullerene containing films of polyethylene in various aromatic solvents of benzene and its derivatives are investigated.

  18. Response of Dome-enclosed Box-type Structure to Underwater Explosion

    O. R. Nandagopan

    2013-07-01

    Full Text Available In the development of underwater sensor systems, the sensor arrays are configured for different shapes like cylindrical, rectangular and spherical depending on the requirement. The rectangular shaped box–type structure discussed here has both top and bottom ends open. Flanges stiffen the top and bottom ends, and gussets are used to connect the flanges with the structure. In this paper, the box-type structure is subjected to non-contact underwater explosion in a shock tank to study the peak free field pressure on the structure. To simulate the actual conditions, the structure is placed in free flooded area and covered with a dome. The free-field peak pressure on the dome and structure are plotted with time. The measured pressure curves are in agreement with the empirical predictions reported in literature. It is concluded that around 85 per cent of the shock impulse acting on the dome is transmitted to the box-type structure. The dome and box-type structure withstood the explosive load, thereby validating their design.Defence Science Journal, 2013, 63(4, pp.381-385, DOI:http://dx.doi.org/10.14429/dsj.63.2130

  19. Structure and fluid evolution of Yili basin and their relation to sandstone type uranium mineralization

    Based on the summary of strata and structure distribution of Yili basin, the relation of structure and fluid evolution to sandstone type ur alum mineraliation are analyzed. It is found that uranium mineralization in Yili basin experienced ore hosting space forming, pre-alteration of hosting space, hosting space alteration and uranium formation stages. (authors)

  20. Response of Dome-enclosed Box-type Structure to Underwater Explosion

    O.R. Nandagopan

    2013-07-01

    Full Text Available In the development of underwater sensor systems, the sensor arrays are configured for different shapes like cylindrical, rectangular and spherical depending on the requirement. The rectangular shaped box–type structure discussed here has both top and bottom ends open. Flanges stiffen the top and bottom ends, and gussets are used to connect the flanges with the structure. In this paper, the box-type structure is subjected to non-contact underwater explosion in a shock tank to study the peak free field pressure on the structure. To simulate the actual conditions, the structure is placed in free flooded area and covered with a dome. The free-field peak pressure on the dome and structure are plotted with time. The measured pressure curves are in agreement with the empirical predictions reported in literature. It is concluded that around 85 per cent of the shock impulse acting on the dome is transmitted to the box-type structure. The dome and box-type structure withstood the explosive load, thereby validating their design.

  1. Best Entry Points for Structured Document Retrieval - Part II: Types, Usage and Effectiveness

    Reid, Jane; Lalmas, Mounia; Finesilver, Karen; Hertzum, Morten

    2006-01-01

    structured documents. This paper examines the concept of best entry points, which are document components from which the user can browse to obtain optimal access to relevant document components. It investigates at the types of best entry points in structured document retrieval, and their usage and...... effectiveness in real information search tasks....

  2. Dance Class Structure Affects Youth Physical Activity and Sedentary Behavior: A Study of Seven Dance Types

    Lopez Castillo, Maria A.; Carlson, Jordan A.; Cain, Kelli L.; Bonilla, Edith A.; Chuang, Emmeline; Elder, John P.; Sallis, James F.

    2015-01-01

    Purpose: The study aims were to determine: (a) how class structure varies by dance type, (b) how moderate-to-vigorous physical activity (MVPA) and sedentary behavior vary by dance class segments, and (c) how class structure relates to total MVPA in dance classes. Method: Participants were 291 boys and girls ages 5 to 18 years old enrolled in 58…

  3. Bismuth zinc vanadate, BiZn{sub 2}VO{sub 6}: New crystal structure type and electronic structure

    Eliziario Nunes, Sayonara [Department of Chemistry, Durham University, South Road, Durham DH1 3LE (United Kingdom); Department of Materials Engineering, Federal University of São Carlos, 13565-905 São Carlos, SP (Brazil); Wang, Chun-Hai; So, Karwei; Evans, John S.O. [Department of Chemistry, Durham University, South Road, Durham DH1 3LE (United Kingdom); Evans, Ivana Radosavljević, E-mail: ivana.radosavljevic@durham.ac.uk [Department of Chemistry, Durham University, South Road, Durham DH1 3LE (United Kingdom)

    2015-02-15

    We report a combined experimental and computational study of the crystal structure and electronic properties of bismuth zinc vanadate, BiZn{sub 2}VO{sub 6}, known for its visible light photocatalytic activity. The crystal structure has been solved from laboratory powder X-ray diffraction data using the repeated minimisations from random starting values method. BiZn{sub 2}VO{sub 6} adopts a new structure type, based on the following building blocks: corner- and edge-sharing ZnO{sub 4} tetrahedra, ZnO{sub 6} octahedra and VO{sub 4} tetrahedra, and Bi{sub 2}O{sub 12} dimers. It is the only known member of the BiM{sub 2}AO{sub 6} (M=Pb, Ca, Cd, Mn, Zn, Mg, Cu; A=V, P, As) family which does not appear to be structurally closely related to others. The electronic structure of BiZn{sub 2}VO{sub 6}, calculated by DFT methods, shows that it is an indirect gap semiconductor with a calculated band gap of 1.6 eV, which compares favourably to the experimentally measured value of 2.4 eV. - Graphical abstract: The crystal structure of BiZn{sub 2}VO{sub 6}, a new structure type in the BiM{sub 2}AO{sub 6} (M=Mg, Ca, Cd, Cu, Pb, Mn, Zn; A=V, P, As) family. - Highlights: • Structure solution from PXRD data by repeated minimisations from random starting values. • New structure type in the BiM{sub 2}AO{sub 6} (M=Pb, Ca, Cd, Mn, Zn, Mg, Cu; A=V, P, As) family. • Electronic structure calculation.

  4. High-pressure structural investigation of several zircon-type orthovanadates

    Errandonea, D.; Lacomba-Perales, R.; Ruiz-Fuertes, J.; SEGURA, A.; Achary, S.N.; Tyagi, A. K.

    2009-01-01

    Room temperature angle-dispersive x-ray diffraction measurements on zircon-type EuVO4, LuVO4, and ScVO4 were performed up to 27 GPa. In the three compounds we found evidence of a pressure-induced structural phase transformation from zircon to a scheelite-type structure. The onset of the transition is near 8 GPa, but the transition is sluggish and the low- and high-pressure phases coexist in a pressure range of about 10 GPa. In EuVO4 and LuVO4 a second transition to a M-fergusonite-type phase ...

  5. Production of C-band disk-loaded type CG accelerating structure

    In April 2013, MITSUBISHI HEAVY INDUSTRIES, LTD. contracted with RIKEN to manufacture six C-band disk-loaded type and constant gradient (CG) accelerating structures for XFEL facility SACLA (SPring-8 Angstrom Compact free electron LAser). These structures were newly designed for operation with an acceleration gradient of over 45 MeV/m and a repletion rate of 120 pps by RIKEN. We report the production and low-power RF properties of these accelerating structures. (author)

  6. An Algorithmic Structuration of a Type System for an Orthogonal Object/Relational Model

    Benabbou, Amel; Amghar, Youssef

    2010-01-01

    Date and Darwen have proposed a theory of types, the latter forms the basis of a detailed presentation of a panoply of simple and complex types. However, this proposal has not been structured in a formal system. Specifically, Date and Darwen haven't indicated the formalism of the type system that corresponds to the type theory established. In this paper, we propose a pseudo-algorithmic and grammatical description of a system of types for Date and Darwen's model. Our type system is supposed take into account null values; for such intention, we introduce a particular type noted #, which expresses one or more occurrences of incomplete information in a database. Our algebraic grammar describes in detail the complete specification of an inheritance model and the subryping relation induced, thus the different definitions of related concepts.

  7. Of the crystal chemistry of Ruddlesden-Porter type structures in high Tc ceramic superconductors

    This paper reports on atomistic computer simulation employed to examine the energetics and crystal chemistry of some Ruddlesden-Popper type oxide superconductors. Similar structural patterns have been noticed in the superconducting oxides. The formation of Ruddlesden-Popper type layers (alternating slabs of rocksalt and perovskite structures) is similar in many respects to that seen in the system Sr-Ti-O. However, there are some significant differences, for example, the rocksalt and perovskite blocks in the new superconducting compounds are not necessarily electrically neutral unlike in the Sr-Ti-O system and this may well lead to significant differences in their structural chemistry

  8. The Types of Argument Structure Used by Hillary Clinton in the CNN Democratic Presidential Debate

    Anggie Angeline; Nani Indrajani T.

    2009-01-01

    This qualitative research was conducted to examine the types of argument structure by Hillary Clinton in part one of the CNN Democratic Presidential Debate since Hillary, who had a great deal of experiences in political parties, was supposed to be able to construct convincing arguments that had good argument structures. The theories used to analyze were Bierman and Assali’s (1996), King’s (n.d.) and Stanlick’s (2003). The findings showed that there were five types of argument structure used: ...

  9. Structural and Thermal Safety Analysis Report for the Type B Radioactive Waste Transport Package

    Kim, D. H.; Seo, K. S.; Lee, J. C.; Bang, K. S

    2007-09-15

    We carried out structural safety evaluation for the type B radioactive waste transport package. Requirements for type B packages according to the related regulations such as IAEA Safety Standard Series No. TS-R-1, Korea Most Act. 2001-23 and US 10 CFR Part 71 were evaluated. General requirements for packages such as those for a lifting attachment, a tie-down attachment and pressure condition were considered. For the type B radioactive waste transport package, the structural, thermal and containment analyses were carried out under the normal transport conditions. Also the safety analysis were conducted under the accidental transport conditions. The 9 m drop test, 1 m puncture test, fire test and water immersion test under the accidental transport conditions were consecutively done. The type B radioactive waste transport packages were maintained the structural and thermal integrities.

  10. Damage identification in shear-type structures using a proper orthogonal decomposition approach

    Wang, Dansheng; Xiang, Wei; Zeng, Peng; Zhu, Hongping

    2015-10-01

    Proper orthogonal modes (POMs) obtained through proper orthogonal decomposition (POD), as a statistical pattern analysis technique, have been physically demonstrated to represent the dominant structure of the dynamic response data in previous study. In this paper, a novel POMs-based damage identification approach for shear-type buildings is developed. First, POMs of acceleration dynamic response of a shear-type building under Gauss White Noise (GWN) ground motion are obtained using singular value decomposition; then, the dominant POMs of acceleration response are used to identify the damage locations and severities through particle swarm optimization (PSO) algorithm. This proposed approach is applied to two three-story shear-type buildings in numerical simulation and a three-story shear-type frame in experimental study. The results demonstrate that the locations and severities of structural damage in shear-type buildings can be effectively identified by using the proposed method.

  11. Variations of Structural Components: Specific Intercultural Differences in Facial Morphology, Skin Type, and Structures

    McKnight, Aisha; Momoh, Adeyiza O.; Bullocks, Jamal M.

    2009-01-01

    Analysis of the differences in facial morphology and skin structure and tone among ethnic groups within the realm of plastic surgery is relevant due to the increasing number of ethnic individuals seeking cosmetic surgery. Previous classifications of ideal facial morphologic characteristics have been revised and challenged over the years to accurately reflect the differences in facial structure that are aesthetically pleasing to individuals of differing ethnic groups. The traditional neoclassi...

  12. Development, characteristics and comparative structural analysis of tensegrity type cable domes

    Nenadović Aleksandra

    2010-01-01

    Full Text Available Tensegrity type cable domes are three-dimensional structural configurations, prestressed inside the perimeter compression ring, in which the continuous tension throughout the roof structure is made by continuous tension cables and discontinuous compression struts. These kinds of structures can be formed like spatially triangulated networks or like networks nontriangulated in space. This paper examines some effects of network geometry on the behaviour and structural efficiency of tensegrity type cable domes. In this paper the roof cover is considered non-interactive with the supporting structure, unlike rigidly clad tensegrity type cable domes. Since the main bearing elements of tensegrity type cable domes are prestressed cables, they show non-linear load deformation and rely upon geometric stiffness. A geometrically non-linear analysis of non-triangulated and triangulated structures for different load conditions was conducted employing a computer program based on the perturbation theory. The incrementally-iterative procedure, with an approximation of the stiffness matrix by combining the elastic and geometric stiffness matrix, allows detection of structural instabilities.

  13. Distinctive structure in dynamic spectra of type V solar radio bursts

    Bakunin, L.M.; Markeev, A.K.; Fomichev, V.V.; Chertok, I.M.

    1979-05-01

    Observations of type V solar radio bursts obtained with a 45--90 MHz radio spectrograph at the Institute of Terrestrial Magnetism are discussed. The dynamic spectra of type V events are highly diversified and complex. Categories of bursts are discriminated, depending on the behavior of the radiation at the leading and trailing edges. Various types of fine structure are encountered in the dynamic spectra of many bursts. An analysis is made of type V bursts that distinctly exhibit radio emission at the frequencies of the fundamental and the second harmonic.

  14. Electrical conductivity and Hf 4+ ion substitution range in NaSICON system

    Essoumhi, A.; Favotto, C.; Mansori, M.; Ouzaouit, K.; Satre, P.

    2007-03-01

    In this paper, we present the synthesis and characterizations of NaSICON-type ionic conducting ceramics of the general formula Na 1+ xM 1.775Si x-0.9P 3.9- xO 12 with 1.8 ≤ x ≤ 2.2 and M = Zr or Hf. The effect of the total substitution of zirconium by hafnium on electric properties has been studied. The various compositions were prepared by using the sol-gel method and the synthesized precursors were characterized by coupled DTA-TG. The oxides obtained after pyrolysis of the precursors were identified by X-ray diffraction. A sintering study by thermodilatometry permits to select the best thermal cycle adapted to our ceramics. Furthermore, the electric conductivity of the sintered ceramic samples was characterized by complex impedance spectroscopy. These results show that ceramics containing Zr synthesized by soft method, present a higher total conductivity than those obtained in literature (to be around 10 -4 S cm -1). The total substitution of Zr by Hf still improves this conductivity for some compositions.

  15. An integrated structural strength analysis method for Spar type floating wind turbine

    Hu, Zhi-qiang; Liu, Yi; Wang, Jin

    2016-04-01

    An integrated structural strength analysis method for a Spar type floating wind turbine is proposed in this paper, and technical issues related to turbine structure modeling and stress combination are also addressed. The NREL-5MW "Hywind" Spar type wind turbine is adopted as study object. Time-domain dynamic coupled simulations are performed by a fully-coupled aero-hydro-servo-elastic tool, FAST, on the purpose of obtaining the dynamic characteristics of the floating wind turbine, and determining parameters for design load cases of finite element calculation. Then design load cases are identified, and finite element analyses are performed for these design load cases. The structural stresses due to wave-induced loads and wind-induced loads are calculated, and then combined to assess the structural strength of the floating wind turbine. The feasibility of the proposed structural strength analysis method for floating wind turbines is then validated.

  16. The Types of Argument Structure Used by Hillary Clinton in the CNN Democratic Presidential Debate

    Anggie Angeline

    2009-01-01

    Full Text Available This qualitative research was conducted to examine the types of argument structure by Hillary Clinton in part one of the CNN Democratic Presidential Debate since Hillary, who had a great deal of experiences in political parties, was supposed to be able to construct convincing arguments that had good argument structures. The theories used to analyze were Bierman and Assali’s (1996, King’s (n.d. and Stanlick’s (2003. The findings showed that there were five types of argument structure used: serial, linked, convergent, divergent, and hybrid argument structures. The linked argument structure was the argument structure used the most frequently in Hillary’s utterances in the debate, while the divergent was the least one. Thus, it could be concluded that Hillary’s speech in the Presidential Debate was quite interesting since she could combine all the five types of argument structure, though the frequency of using them was not the same and it seems that linked argument structure was the most effective strategy for her in arguing about the politic, economy, and social issues.

  17. In Situ D-periodic Molecular Structure of Type II Collagen

    Antipova, Olga; Orgel, Joseph P.R.O. (IIT)

    2010-05-06

    Collagens are essential components of extracellular matrices in multicellular animals. Fibrillar type II collagen is the most prominent component of articular cartilage and other cartilage-like tissues such as notochord. Its in situ macromolecular and packing structures have not been fully characterized, but an understanding of these attributes may help reveal mechanisms of tissue assembly and degradation (as in osteo- and rheumatoid arthritis). In some tissues such as lamprey notochord, the collagen fibrillar organization is naturally crystalline and may be studied by x-ray diffraction. We used diffraction data from native and derivative notochord tissue samples to solve the axial, D-periodic structure of type II collagen via multiple isomorphous replacement. The electron density maps and heavy atom data revealed the conformation of the nonhelical telopeptides and the overall D-periodic structure of collagen type II in native tissues, data that were further supported by structure prediction and transmission electron microscopy. These results help to explain the observed differences in collagen type I and type II fibrillar architecture and indicate the collagen type II cross-link organization, which is crucial for fibrillogenesis. Transmission electron microscopy data show the close relationship between lamprey and mammalian collagen fibrils, even though the respective larger scale tissue architecture differs.

  18. Optimum Design for Slot-type of Stator Based on PM Motor with Halbach Structure

    Zhu Yongxin

    2015-01-01

    Full Text Available The performance of permanent magnet motor is directly influenced by the PM structure of rotor and the slot type of stator. An emerging rotor magnetization type of PM motor is Halbach structure, which has obvious advantages in comparison to ordinary permanent structures and in application, especially in the design of propeller integration system. Commonly, Halbach array is used in discrete permanent magnet structure on the rotor of machine. On the stator, air gap flux density varies as the slot type changes, and complex slot types will bring about complex air gap equivalent process of the motor, which will influence the procedures of simulation calculation and experiments. According to the characteristics of Halbach array, the intensifying effect of the Halbach array on magnetic flux density of air gap is analyzed in this paper, and the electromagnetic field of PM motor is calculated. By using FEM method, the magnetic flux density of air gap, back phase electromotive force and electromagnetic torque are compared under different slot types. Simulation result shows the peer slot is best. Experiments on a 60kW PM Motor with Halbach Structure and peer slot is in good agreement with simulation.

  19. Outer-Sphere Contributions to the Electronic Structure of Type Zero Copper Proteins

    Lancaster, Kyle M.; Zaballa, María-Eugenia; Sproules, Stephen; Sundararajan, Mahesh; DeBeer, Serena; Richards, John H.; Vila, Alejandro J.; Neese, Frank; Gray, Harry B.

    2016-01-01

    Bioinorganic canon states that active-site thiolate coordination promotes rapid electron transfer (ET) to and from type 1 copper proteins. In recent work, we have found that copper ET sites in proteins also can be constructed without thiolate ligation (called “type zero” sites). Here we report multifrequency electron paramagnetic resonance (EPR), magnetic circular dichroism (MCD), and nuclear magnetic resonance (NMR) spectroscopic data together with density functional theory (DFT) and spectroscopy-oriented configuration interaction (SORCI) calculations for type zero Pseudomonas aeruginosa azurin variants. Wild-type (type 1) and type zero copper centers experience virtually identical ligand fields. Moreover, O-donor covalency is enhanced in type zero centers relative that in the C112D (type 2) protein. At the same time, N-donor covalency is reduced in a similar fashion to type 1 centers. QM/MM and SORCI calculations show that the electronic structures of type zero and type 2 are intimately linked to the orientation and coordination mode of the carboxylate ligand, which in turn is influenced by outer-sphere hydrogen bonding. PMID:22563915

  20. Cryo-EM structures of two bovine adenovirus type 3 intermediates

    Cheng, Lingpeng; Huang, Xiaoxing; Li, Xiaomin [National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101 (China); Xiong, Wei [State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Luo-jia-shan, Wuhan, Hubei 430072 (China); Sun, Wei; Yang, Chongwen; Zhang, Kai; Wang, Ying [National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101 (China); Liu, Hongrong [College of Physics and Information Science, Hunan Normal University, Changsha, Hunan 410081 (China); Huang, Xiaojun; Ji, Gang; Sun, Fei [National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101 (China); Zheng, Congyi, E-mail: cctcc202@whu.edu.cn [State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Luo-jia-shan, Wuhan, Hubei 430072 (China); Zhu, Ping, E-mail: zhup@ibp.ac.cn [National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101 (China)

    2014-02-15

    Adenoviruses (Ads) infect hosts from all vertebrate species and have been investigated as vaccine vectors. We report here near-atomic structures of two bovine Ad type 3 (BAd3) intermediates obtained by cryo-electron microscopy. A comparison between the two intermediate structures reveals that the differences are localized in the fivefold vertex region, while their facet structures are identical. The overall facet structure of BAd3 exhibits a similar structure to human Ads; however, BAd3 protein IX has a unique conformation. Mass spectrometry and cryo-electron tomography analyses indicate that one intermediate structure represents the stage during DNA encapsidation, whilst the other intermediate structure represents a later stage. These results also suggest that cleavage of precursor protein VI occurs during, rather than after, the DNA encapsidation process. Overall, our results provide insights into the mechanism of Ad assembly, and allow the first structural comparison between human and nonhuman Ads at backbone level. - Highlights: • First structure of bovine adenovirus type 3. • Some channels are located at the vertex of intermediate during DNA encapsidation. • Protein IX exhibits a unique conformation of trimeric coiled–coiled structure. • Cleavage of precursor protein VI occurs during the DNA encapsidation process.

  1. Electron diffraction study of the influence of bonding type on grain boundary structure

    Vaudin, M.D.; Schmueckle, F.; Lamarre, P.; Sass, S.L. (Cornell Univ., Ithaca, NY (USA))

    By looking at the scattering normal to the interface, diffraction data is obtained which is sensitive only to changes in structure along this direction. The influence of bonding type on grain boundary structure was studied by using this diffraction approach to examine the same type of boundary (({theta} = 22.6{degree})(001) twist boundary) in NiO, Au and Ge. Each boundary was manufactured in the form of a bicrystal and examined using electron diffraction. Major differences were observed among the diffraction effects from the three boundaries. Extensive diffraction calculations were performed in order to interpret the observations in terms of structural models of the boundary. It is speculated that the differences in the diffraction observations are related to the type of bonding.

  2. Determination of a new structure type in the Sc–Fe–Ge–Sn system

    Highlights: ► A new structure type with the composition Sc4Fe5Ge6.10(3)Sn1.47(2). ► Crystallizes in the space group Immm (No. 71, oI144). ► Sample obtained using a reactive Sn flux. ► Electronic structure calculations indicate polar intermetallic bonding network. - Abstract: A new structure type has been discovered in the system Sc–Fe–Ge–Sn by employing Sn as a flux medium. According to single crystal X-ray diffraction, the new structure has a composition of Sc4Fe5Ge6.10(3)Sn1.47(2) and crystallizes in the space group Immm (No. 71, oI144) with lattice parameters of a = 5.230(1) Å, b = 13.467(3) Å, and c = 30.003(6) Å. The structure is composed of square anti-prismatic clusters that are condensed into zig-zag chains along the [0 1 0] direction. These chains are further condensed through a split Sn/Ge position, forming a three-dimensional network. Magnetization measurements indicate an antiferromagnetic phase transition near 240 K. Electronic structure calculations identified the most favorable bonding network in this new system. Using crystal orbital Hamilton population (COHP) curves and their integrated values (ICOHP), a polar intermetallic bonding network involving Sc–Ge as well as Fe–Sn and Fe–Ge contacts can be assigned to this new structure type.

  3. Recent advances in understanding structure-function relationships in the type II topoisomerase mechanism.

    Schoeffler, A J; Berger, J M

    2005-12-01

    DNA topos (topoisomerases) are complex, multisubunit enzymes that remodel DNA topology. Members of the type II topo family function by passing one segment of duplex DNA through a transient break in another, a process that consumes two molecules of ATP and requires the co-ordinated action of multiple domains. Recent structural data on type II topo ATPase regions, which activate and enforce the directionality of DNA strand passage, have highlighted how ATP physically controls the catalytic cycle of the enzyme. Structural and biochemical studies of specialized DNA-binding domains in two paralogous bacterial type IIA topos (DNA gyrase and topo IV) show how these enzymes selectively negatively supercoil or decatenate DNA. Taken together, these findings expand our understanding of how disparate functional elements work together to co-ordinate the type II topo mechanism. PMID:16246147

  4. Characteristics of Core Promoter Types with respect to Gene Structure and Expression in Arabidopsis thaliana

    Yamamoto, Yoshiharu Y; Yoshioka, Yohei; Hyakumachi, Mitsuro; Obokata, Junichi

    2011-01-01

    It is now well known that vertebrates use multiple types of core promoter to accomplish differentiated tasks in Pol II-dependent transcription. Several transcriptional characteristics are known to be associated with core types, including distribution patterns of transcription start sites (TSSs) and selection between tissue-specific and constitutive expression profiles. However, their relationship to gene structure is poorly understood. In this report, we carried a comparative analysis of thre...

  5. Structure of the glycosaminoglycan domain in the type IX collagen-proteoglycan.

    McCormick, D; van der Rest, M; Goodship, J.; Lozano, G; Ninomiya, Y; Olsen, B. R.

    1987-01-01

    Type IX collagen represents 5-20% of the total collagen in hyaline cartilage. The molecules of this collagen are composed of three genetically distinct polypeptide subunits. One of these subunits, alpha 2(IX), contains covalently bound glycosaminoglycan (chondroitin sulfate or dermatan sulfate). We report here on the structure of the glycosaminoglycan attachment site of type IX collagen-proteoglycan. We show, by a combination of cDNA and peptide sequencing, that the attachment region contains...

  6. Arithmetic of Property Rights: A Leontief-type Model of Ownership Structures

    František Turnovec

    2005-01-01

    A simple algebraic model of a property structure leading to the Leontief-type input-output scheme is developed and used to eliminate indirect ownership relations and evaluate the final distribution of national property among individual owners. Concepts of "family capitalism" and "capitalism of agents" type of corporate governance are defined and compared. Implications of different designs of corporate governance for general equilibrium theory, profit distribution and decision making are discu...

  7. Heat Transfer and Flow Structure in a Rectangular Channel With Wing-Type Vortex Generator

    KOTCİOĞLU, İsak

    1998-01-01

    A detailed evaluation of performance parameters in the turbulent regime with regard to the enhancement of heat transfer using winglet-type vortex generators has been accomplished in this study. The heat transfer characteristics and flow structure in turbulent flow throught a rectangular channel containing built-in wing type vortex generator, have been investigated experimentally in the range of Reynolds number between 3,000 and 30,000. The geometrical configuration of interest is rem...

  8. Variance of the Boundary Layer Structure in Dependence of distinct Circulation Types

    Philipp, Andreas; Beck, Christoph; Jacobeit, Jucundus

    2015-04-01

    Variability of local climate features is related on the one hand to large scale circulation patterns, but is modified additionally by regional or local influences. This is true for basic climate variables like temperature and precipitation but also for more complex environmental conditions like air quality, e.g. PM10 concentration. Regional and local influences are to a large extend represented by the atmosperic boundary structure, i.e. the height of the mixed layer or its stability determining fluxes of temperature and impulse as well as water vapor etc. The presented study focusses on the interaction between the boundary layer structure and large scale circulation types for selected radiosonde stations. Crculation is described by a k-means cluster analysis of European circulation fields, retrieved from the NCEP/NCAR reanalysis. The boundary layer structure is derived from European radiosonde data collected in the Integrated Global Radiosonde Archive (IGRA). Here the mixed layer heigth and stability indices are anaylsed for within-type variance in a first step for different circulation types created independently from any other information. In a second step circulation types are created including boundary layer information. Both kinds of types are then realted to local impact variables in order to achieve conclusions about the interdependence of both, the large scale circulation and the boundary layer structure in modifying local climate variables.

  9. Prediction, conservation analysis, and structural characterization of mammalian mucin-type O-glycosylation sites

    Julenius, Karin; Mlgaard, Anne; Gupta, Ramneek; Brunak, Sren

    2004-01-01

    than a nonglycosylated one. The Protein Data Bank was analyzed for structural information, and 12 glycosylated structures were obtained. All positive sites were found in coil or turn regions. A method for predicting the location for mucin-type glycosylation sites was trained using a neural network...... could be predicted from averaged properties together with the fact that glycosylation sites are not precisely conserved indicates that mucin-type glycosylation in most cases is a bulk property and not a very site-specific one. NetOGlyc 3.1 is made available at www.cbs.dtu.dk/services/netoglyc....

  10. Structure and Composition of Protein Bodies from Wild-Type and High-Lysine Barley Endosperm

    Ingversen, J.

    1975-01-01

    granular component. Particles with the same structure were present in the protein body preparation from the mutant, where, however, the granular component was the most prominent. Amino-acid composition and SDS-polyacrylamide gel electrophoresis of the proteins from the protein body preparation revealed......-polyacrylamidegel electrophoresis. Sections through pellets of isolated protein bodies from both the mutant and the wild type revealed protein body structures corresponding with those observed in sections through the intact starchy endosperms. The majority of the wild-type protein bodies was homogeneous spheres accompanied with a...

  11. A Study of the Types of Organizational Structure in Venezuelan University Institutes

    Rafael Antonio Pertuz Belloso

    2013-12-01

    Full Text Available This study aimed at identifying the type of organizational structure of Venezuelan university institutes. It is a field investigation of a descriptive nature with a non-experimental transactional field design. We worked with a population sample consisting of a director, assistant directors, academic assistant directors and eighty-eight teachers from technological institutes in Cabimas and Maracaibo in Venezuela. A survey, in the form of a questionnaire, was used as the data collection technique, which included 24 items, validated by 5 experts, with Cronbach Alpha reliability of 0.93. The data analysis technique utilized was the percentage frequency distribution. The results indicated the coexistence of bureaucratic structural typologies; departmental and simple. An implementation of a structural migration strategy to the implementation of a matrix-type structure is recommended.

  12. Novel Compact Mushroom-Type EBG Structure for Electromagnetic Coupling Reduction of Microstrip Antenna array

    Hu, Lizhong; Wang, Guangming; Liang, Jiangang; Zhang, Chenxin

    2015-03-01

    A novel compact electromagnetic bandgap (EBG) structure consisting of two turns complementary spiral resonator (CSR) and conventional mushroom EBG (CM-EBG) structure is introduced to suppress the mutual coupling in antenna arrays for multiple-input and multiple-output (MIMO) applications. Eigenmode calculation is used to investigate the proposed CSR-loaded mushroom-type EBG (MT-EBG), which proved to exhibit bandgap property and a miniaturization of 48.9% is realized compared with the CM-EBG. By inserting the proposed EBG structure between two E-plane coupled microstrip antennas, a mutual coupling reduction of 8.13 dB has been achieved numerically and experimentally. Moreover, the EBG-loaded antenna has better far-field radiation patterns compared with the reference antenna. Thus, this novel EBG structure with advantages of compactness and high decoupling efficiency opens an avenue to new types of antennas with super performances.

  13. Universal properties of type IIB and F-theory flux compactifications at large complex structure

    Marsh, M. C. David; Sousa, Kepa

    2016-03-01

    We consider flux compactifications of type IIB string theory and F-theory in which the respective superpotentials at large complex structure are dominated by cubic or quartic terms in the complex structure moduli. In this limit, the low-energy effective theory exhibits universal properties that are insensitive to the details of the compactification manifold or the flux configuration. Focussing on the complex structure and axio-dilaton sector, we show that there are no vacua in this region and the spectrum of the Hessian matrix is highly peaked and consists only of three distinct eigenvalues (0, 2 m 3/2 2 and 8 m 3/2 2 ), independently of the number of moduli. We briefly comment on how the inclusion of Kähler moduli affect these findings. Our results generalise those of Brodie & Marsh [1], in which these universal properties were found in a subspace of the large complex structure limit of type IIB compactifications.

  14. The indentification of Jueluotage V-type structure in Xinjiang and its orderness

    Based on the interpretation of satellite image and field checking in Jueluotage area, Xinjiang, it is thought that the sublatitudinal arc fault zones have been formed since Mesozoic through the evolution of the NWW-trending and NEE-trending faults occurring in pre-Mesozoic time. These three sets of faults comprise the Jueluotage 'V-type structure' formed by the NW-trending structural stress field and drastically activated since Neocene. The Jueluotage V-type structure is expressed in time as an ordered process, and in space as an ordered arrangement and an ordered evolution direction, and characterizes the Information Ordered Series (IOS) of the evolution process of fault structure. (authors)

  15. Structural Design Studies for a Large Pool Type SFR of 1200 MWe

    The conceptual design studies of a sodium-cooled fast reactor (SFR) have been performed. The reactor is a pool type and 2-loop system with an 1200 MWe electrical capacity. The core outlet temperature is 545 deg. C, and the inlet one is 390 deg. C. Most internal structures and components are exposed to a high temperature environment. The mechanical governing loads of the reactor are the thermal and seismic loads because of the low operating pressure at an atmospheric level. The structural design targets are to maintain enough structural integrity for the high temperature thermal loads and for a seismic load of SSE 0.3g. Also an important target is to attain its economical competitiveness compared to other reactor types. Several structural design concepts are suggested to obtain the economical improvement of the NSSS (Nuclear Steam Supply System). (author)

  16. The Extracellular Architecture of Adherens Junctions Revealed by Crystal Structures of Type I Cadherins

    O Harrison; X Jin; S Hong; F Bahna; G Ahlsen; J Brasch; Y Wu; J Vendome; K Felsovalyi; et al.

    2011-12-31

    Adherens junctions, which play a central role in intercellular adhesion, comprise clusters of type I classical cadherins that bind via extracellular domains extended from opposing cell surfaces. We show that a molecular layer seen in crystal structures of E- and N-cadherin ectodomains reported here and in a previous C-cadherin structure corresponds to the extracellular architecture of adherens junctions. In all three ectodomain crystals, cadherins dimerize through a trans adhesive interface and are connected by a second, cis, interface. Assemblies formed by E-cadherin ectodomains coated on liposomes also appear to adopt this structure. Fluorescent imaging of junctions formed from wild-type and mutant E-cadherins in cultured cells confirm conclusions derived from structural evidence. Mutations that interfere with the trans interface ablate adhesion, whereas cis interface mutations disrupt stable junction formation. Our observations are consistent with a model for junction assembly involving strong trans and weak cis interactions localized in the ectodomain.

  17. Universal Properties of Type IIB and F-theory Flux Compactifications at Large Complex Structure

    Marsh, M C David

    2015-01-01

    We consider flux compactifications of type IIB string theory and F-theory in which the respective superpotentials at large complex structure are dominated by cubic or quartic terms in the complex structure moduli. In this limit, the low-energy effective theory for the complex structure and axio-dilaton sector exhibits universal properties that are insensitive to the details of the compactification manifold or the flux configuration. We show that there are no vacua in this region and the spectrum of the Hessian matrix is highly peaked and consists only of three distinct eigenvalues ($0$, $2m_{3/2}^2$ and $8m_{3/2}^2$), independently of the number of moduli. We briefly comment on how the inclusion of K\\"ahler moduli affect these findings. Our results generalise those of Brodie & Marsh [1], in which these universal properties were found in a subspace of the large complex structure limit of type IIB compactifications.

  18. Ce2Ir5B2, a new structure type of ternary borides

    The crystal structure of a new ternary boride Ce2Ir5B2, space group R3-bar m, a=5.477(2) A, c=31.518(5) A, Z=6, V=818.79 A, was refined down to R=0.0484, wR2=0.1211 from single crystal X-ray diffraction data. This is the first representative of a new structure type of intermetallic compounds (an ordered variant of the binary Er2Co7 compound). The structure of Ce2Ir5B2 is the stacking variant of the MgCu2- and CeCo3B2-type slabs and belongs to the structural series with the general formula R2+nM4+3nX2n (n=2)

  19. Croatian banking sector research: relationship between ownership structure, concentration, owners’ type and bank performance

    Igor Tomičić; Ana Ćorić; Marina Klačmer Čalopa

    2012-01-01

    Banks are important financial intermediaries of any national economy, and corporate governance has an important role in banking sector; especially due to processes of the globalization and the internationalization, and also because of the sensitivity of the activities between the interest groups. The objective of this paper is to examine the relationship between ownership structure, concentration, owners’ type and bank performance. The authors made a research of banks' ownership structure usi...

  20. Structure, process, and outcomes of care in a telemonitoring program for patients with type 2 diabetes

    Nocella JM; Dickson VV; Clel; CM; Melkus GD

    2016-01-01

    Jill M Nocella,1 Victoria Vaughan Dickson,2 Charles M Cleland,2 Gail D’Eramo Melkus2 1Department of Nursing, William Paterson University, Wayne, NJ, 2College of Nursing, New York University, New York, NY, USA Background: Using Donabedian's structure-process-outcomes (SPO) framework, this descriptive, exploratory study examined the structure of a telemonitoring program in a population of patients with type 2 diabetes (T2D), the process of nurse–patient telephonic interactions,...

  1. Nomenclature of inorganic structure types; Report of the International Union of Crystallography Commission on Crystallographic Nomenclature Subcommittee on the Nomenclature of Inorganic Structure Types

    Lima-de-Faria, J. (Instituto de Investigacao Cientifica Tropical, Lisbon (Portugal). Centro de Cristalografia e Mineralogia (Portugal)); Hellner, E. (Marburg Univ. (Germany, F.R.). Fachbereich 18 - Geowissenschaften (Germany, F.R.)); Liebau, F. (Kiel Univ. (Germany, F.R.). Mineralogisches Inst. (Germany, F.R.)); Makovicky, E. (Copenhagen Univ. (Denmark). Inst. for Mineralogy (Denmark)); Parthe, E. (Geneva Univ. (Switzerland). Lab. Crystallographie aux Rayons X (Switzerland))

    1990-01-01

    Different degrees of similarity between inorganic crystal structures are defined concisely and examples are presented that illustrate their practical application. A notation giving the coordination of atoms is presented together with some basic rules for developing crystal-chemical formulae and the Bauverband description of inorganic structure types. Typical examples of the nomenclature are: pyrite Fe{sup 6o}{l brace}g{r brace} S{sub 2} {sup (3;(1)t)}, F {radical} 2l + F'FeS{sub 2} Pa{anti 3}; spinel Mg{sup (4)}Al{sub 2} {sup 6}O{sub 4}, {sub {infinity}}{sup 3} Mg{sup (4t)}Al{sub 2} {sup 6o}O{sub 4}{sup (1,3; 12 co)}, F'' {sub 222} + C, T'MgAl{sub 2} O{sub 4} Fd {anti 3}m. (orig.).

  2. Two types of dynamic cool coronal structures observed with STEREO and Hinode

    Solar coronal loops show significant plasma motions during their formation and eruption stages. Dynamic cool coronal structures, on the other hand, are often observed to propagate along coronal loops. We report on the discovery of two types of dynamic cool coronal structures, and characterize their fundamental properties. Using the EUV 304 A images from the Extreme Ultra Violet Imager (EUVI) telescope on the Solar TErrestrial RElation Observatory (STEREO) and the Ca II filtergrams from the Solar Optical Telescope (SOT) instrument on Hinode, we study the evolution of an EUV arch and the kinematics of cool coronal structures. The EUV 304 A observations show that a missile-like plasmoid moves along an arch-shaped trajectory, with an average velocity of 31 km s-1. About three hours later, a plasma arch forms along the trajectory, subsequently the top part of the arch fades away and disappears; meanwhile the plasma belonging to the two legs of the arch flows downward to the arch's feet. During the arch formation and disappearance, SOT Ca II images explore dynamic cool coronal structures beneath the arch. By tracking these structures, we classify them into two types. Type I is threadlike in shape and flows downward with a greater average velocity of 72 km s -1; finally it combines with a loop fibril at a chromospheric altitude. Type II is shape-transformable and sometimes rolling as it flows downward with a smaller velocity of 37 km s -1, then disappears insularly in the chromosphere. It is suggested that the two types of structures are possibly controlled by different magnetic configurations.

  3. The electronic structure of zircon-type orthovanadates: Effects of high-pressure and cation substitution

    Panchal, V.; Errandonea, D.; SEGURA, A.; Rodriguez-Hernandez, P.; Munoz, A.; Lopez-Moreno, S.; Bettinelli, M.

    2012-01-01

    The electronic structure of four ternary-metal oxides containing isolated vanadate ions is studied. Zircon-type YVO4, YbVO4, LuVO4, and NdVO4 are investigated by high-pressure optical-absorption measurements up to 20 GPa. First-principles calculations based on density-functional theory were also performed to analyze the electronic band structure as a function of pressure. The electronic structure near the Fermi level originates largely from molecular orbitals of the vanadate ion, but cation s...

  4. Parametric identification of electric equipment with column-type structure. Part 1 - Method for parametric identification

    In the paper there is presented a method for parametric identification of the electric equipment with column - type structure using the one point excitation method with steady-state sinusoidal signals. On the basis of the determined modal parameters the theoretical analysis of the dynamic response (in displacements or accelerations) at mechanical stresses applied in its distinct points is done. (Author) 3 Refs

  5. Hamiltonian structure for a class of parametric coupled systems of the Korteweg-de Vries type

    We obtain from a lagrangian action describing a class of coupled parametric systems of KdV type its hamiltonian structure. The Poisson algebra arises from second class constraints of the theory and the use of Dirac brackets. The coupled system has relevant applications in physics

  6. Expressibility of the logic SOF on classes of structures of bounded FO types

    Grosso, Alejandro; Turull Torres, José María

    2012-01-01

    We introduce a new property for classes of structures (or relational database instances), that we call bounded FO types. Then we prove that on such classes the expressive power of SOF collapses to rst order logic FO. As a consequence of this we prove that SOF is strictly included in SO.

  7. Crystal structure of a copper-transporting PIB-type ATPase

    Gourdon, Pontus Emanuel; Liu, Xiang-Yu; Skjørringe, Tina; Morth, J Preben; Møller, Lisbeth Birk; Pedersen, Bjørn Panyella; Nissen, Poul

    2011-01-01

    Heavy-metal homeostasis and detoxification is crucial for cell viability. P-type ATPases of the class IB (PIB) are essential in these processes, actively extruding heavy metals from the cytoplasm of cells. Here we present the structure of a PIB-ATPase, a Legionella pneumophila CopA Cu(+)-ATPase, ......7B proteins associated with Menkes' and Wilson's diseases....

  8. Pre-adsorbed type-I collagen structure-dependent changes in osteoblastic phenotype

    Type-I collagen is the most abundant extracellular matrix in bones and modulates various functions of osteoblasts. We prepared two different structures of type-I collagen on tissue culture grade polystylene (TCPS) surfaces, one is feltwork structure of filamentous molecules from acid solutions (ACs) and the other is network structure of fibrils from neutral solutions (NCs), to examine effects of the structures on the maturation process of osteoblast-like cells. No significant differences of cell proliferation were observed between TCPS and ACs, but NCs delayed the proliferation. In initial cell attachment, the cells on ACs had tense lamellipodia with sharp tips, while those on NCs had loose lamellipodia. No detectable differences in levels of expressed integrin α2- and α5-subunits were observed between the structures. Although the matrix mineralization in NCs was also delayed in comparison with TCPS and ACs, fully mineralized levels in NCs were the same as those of TCPS and ACs. In addition, although we examined the effects of densities of pre-adsorbed collagen molecules on osteoblast maturation, the effects were less serious than those of the structures. This study suggests that the structures of collagen affect proliferation and mineralization of osteoblast-like cells

  9. Proposal of a separated-type proton drift tube linac for a medium-energy structure

    A separated-type drift tube linac for medium energies from 150 to 300 MeV is proposed for a continuous-beam proton linac. The average effective shunt impedance increases by 55% compared with that of an alternating-periodic structure of the on-axis coupling type. Some technical difficulties in the manufacturing, alignment and cooling of the drift tube linac are greatly reduced by eliminating the focusing quadrupole magnets from the drift tubes. A modified design of a high-energy, high-average current 1-GeV proton linac with a continuous-beam is presented. It is pointed out that sudden transitions of focusing forces on both transverse and longitudinal motions, due to a change in the type of accelerating structure, are induced at two separated spots in the modified linac. On the contrary, they are induced simultaneously at the same spot in the originally proposed linac. (author)

  10. Morphological and structural characteristics of powders of alumina by reaction combustion obtained through different types containers

    Among the existing types of synthesis, synthesis by combustion reaction is an effective method to produce nano-sized particles. The metallic nitrates that are sources of cations to form metal oxide, react with the fuel reducer quick, exothermic and self-sustaining. This paper aims to analyze the influence of container type on morphology and structural alumina powders obtained by combustion reaction. We evaluated two types of containers: vitreous silica crucible and crucible steel. The structural and morphological characteristics of the powders were analyzed by XRD, textural analysis by adsorption/desorption of N2 and SEM. The results showed the formation of single phase of alpha-Al2O4 for the two samples, showing a very significant difference between their respective surface areas. The morphology was comprised of pre-sintered particles without interparticle porosity forming thin plates of different sizes. (author)

  11. Relationship between the structural stability with the types and land uses in southeastern Spain

    Structural stability is one of the most important physical properties and is proposed as an indicator of quality. The aim of this study is to see the possible relationship between this property with soil types and uses of them. In this paper we have selected the Mazarron area based on their environmental characteristics and has taken forty-one topsoil samples, after analysis and study of the relationship between its structural stability with soil types and uses of same, we find a closer relationship in the case of uses that type, so that the natural soil as the percentage of stable aggregates close to 75%, while in soils anthropized this value reaches 44 %. (Author) 6 refs

  12. Vector-type four-quark interaction and its impact on QCD phase structure

    Effects of the vector-type four-quark interaction on QCD phase structure are investigated in the imaginary chemical potential (μ) region, by using the Polyakov-loop extended Nambu-Jona-Lasinio model with the extended Z3 symmetry. We clarify analytically the Roberge-Weiss periodicity and symmetry properties of various quantities under the existence of a vector-type four-quark interaction. In the imaginary μ region, the chiral condensate and the quark-number density are sensitive to the strength of the interaction. Based on this result, we propose a possibility to determine the strength of the vector-type interaction, which largely affects QCD phase structure in the real μ region, by comparing the results of lattice simulations and effective model calculations in the imaginary μ region.

  13. Perturbation method of analyzing mode localization of asymmetrical plate-type structure in incompressible flows

    The dynamical characteristics of a simple two-span parallel flat plate-type model vibrating in incompressible water are studied here. The assumption mode method is used to form the motion equation of the structure. By using a second order perturbation method, the great emphasis is focused on the influences of the asymmetrical parameter of the structure, the deviation of length and stiffness of the torsional spring on the degrees of mode localization of the structure. The results show that the second method can be applied to predict the dynamical characteristics of the structure accurately. The influences of the coupling effect of the fluid on the phenomena of the two piece beams' mode localization are different. The asymmetrical parameter of length is the main factor that leads to the behaviors of mode localization of the structure. The deviation of stiffness of the torsional spring, too, has significant influences on the phenomena of mode localization

  14. Observation of Current Structures at Type-III ELM Onset on EAST

    Yan, Ning; Naulin, Volker; Xu, G.; Xiong, H.; Wang, H.; Jiang, M.; Liu, P.; Wang, L.; Liu, S.; Zhang, W.; Shao, L.; Wan, B.

    In far scrape-o layer (SOL), alternating negative and positive burst structures in ion saturation current were detected at the onset of each type-III edge localized mode (ELM) on EAST. Different from the fast streaming phenomenon reported previously, one subsequent positive burst structure appears...... single peak mode on the poloidal induction signal in this transitional phase. As a local diagnostic, the floating potential arises abruptly in this phase, indicating the emergence or passage of polarized plasma structure. Further more, the ELM crash enter into another phase after this sudden burst...... structure. To verify the current characteristic of this structure, a mono-polar current filaments model was involved, which can reproduce same pattern commendably. Thus, current transport may dominant in transitional stage and plays an important role in the nonlinear development phase of ELM exhaustive...

  15. Croatian banking sector research: relationship between ownership structure, concentration, owners’ type and bank performance

    Igor Tomičić

    2012-12-01

    Full Text Available Banks are important financial intermediaries of any national economy, and corporate governance has an important role in banking sector; especially due to processes of the globalization and the internationalization, and also because of the sensitivity of the activities between the interest groups. The objective of this paper is to examine the relationship between ownership structure, concentration, owners’ type and bank performance. The authors made a research of banks' ownership structure using publicly available data. Using statistical tools authors discovered relationships between bank ownership structure and bank performance indicators (average asset, total asset, average equity, profit (loss before taxes, profit (loss after taxes, ROAA, ROAE. Further they discuss the relationships between ownership structure and a number of consequences for the bank performance. The authors discovered significant correlation between bank ownership structure and performance indicators variables that are described in the paper.

  16. Structural limitations for optimizing garnet-type solid electrolytes: a perspective.

    Zeier, Wolfgang G

    2014-11-21

    Lithium ion batteries exhibit the highest energy densities of all battery types and are therefore an important technology for energy storage in every day life. Today's commercially available batteries employ organic polymer lithium conducting electrolytes, leading to multiple challenges and safety issues such as poor chemical stability, leakage and flammability. The next generation lithium ion batteries, namely all solid-state batteries, can overcome these limitations through employing a ceramic Li(+) conducting electrolyte. In the past decade, there has been a major focus on the structural and ionic transport properties of lithium-conducting garnets, and the extensive research efforts have led to a thorough understanding of the structure-property relationships in this class of materials. However, further improvement seems difficult due to structural limitations. The purpose of this Perspective article is to provide a brief structural overview of Li conducting garnets and the structural influence on the optimization of Li-ionic conductivities. PMID:25277079

  17. Secondary cyclic hardening and dislocation structures in type 316 stainless steel at 6000C

    Polycrystalline type 316 stainless steel has been fatigued in air and in vacuum at 6000C at two constant plastic strain amplitudes. Although in air the curve of cyclic stress versus number of cycles is prematurely interrupted by failure, in vacuum it is sufficiently extended to allow secondary cyclic hardening to occur. Transmission electron microscopy observations show dislocation configurations (during the fatigue life) which are similar for both strain amplitudes. During the saturation plateau, several configurations coexist: regular walls, a labyrinth structure and persistent slip bands (PSBs) with a ladder structure. At failure (in vacuum) a cellular structure widely prevails while a labyrinth structure and PSBs with a ladder structure no longer exist. (orig./IHOE)

  18. The primary structure of a novel goose-type lysozyme from rhea egg white.

    Pooart, Jureerut; Torikata, Takao; Araki, Tomohiro

    2004-01-01

    G-type lysozyme is a hydrolytic enzyme sharing a similar tertiary structure with plant chitinase. To discover the relation of function and structure, we analyzed the primary structure of new G-type lysozyme. The complete 185 amino acid residues of lysozyme from rhea egg white were sequenced using the peptides hydrolyzed by trypsin, V8 protease, and cyanogen bromide. Rhea lysozyme had sequence similarity to ostrich, cassowary, goose, and black swan, with 93%, 90%, 83%, and 82%, respectively. The six substituted positions were newly found at positions 3 (Asn), 9 (Ser), 43 (Arg), 114 (Ile), 127 (Met), and 129 (Arg) when compared with ostrich, cassowary, goose, and black swan lysozymes. The amino acid substitutions of rhea lysozyme at subsite B were the same as ostrich and cassowary lysozymes (Ser122 and Met123). This study was also constructed in a phylogenetic tree of G-type lysozyme that can be classified into at least three groups of this enzyme, namely, group 1; rhea, ostrich, and cassowary, group 2; goose, black swan, and chicken, and group 3; Japanese flounder. The amino acid sequences in assembled three alpha-helices found in this enzyme group (Thammasirirak, S., Torikata, T., Takami, K., Murata, K., and Araki, T., Biosci. Biotechnol. Biochem., 66, 147-156 (2002)) were also highly conserved, so that they were considered to be important for the formation of the hydrophobic core structure of the catalytic site and for maintaining a similar three-dimensional structure in this enzyme group. PMID:14745179

  19. Analysis of waves in the plasma guided by a periodical vane-type slow wave structure

    In this study, the dispersion relation has been derived to characterize the propagation of the waves in the plasma guided by a periodical vane-type slow wave structure. The plasma is confined by a quartz plate. Results indicate that there are two different waves in this structure. One is the plasma mode that originates from the plasma surface wave propagating along the interface between the plasma and the quartz plate, and the other is the guide mode that originally travels along the vane-type slow wave structure. In contrast to its original slow wave characteristics, the guide mode becomes a fast wave in the low-frequency portion of the passband, and there exists a cut-off frequency for the guide mode. The vane-type guiding structure has been shown to limit the upper frequency of the passband of the plasma mode, compared with that of the plasma surface wave. In addition, the passband of the plasma mode increases with the plasma density while it becomes narrower for the guide mode. The influences of the parameters of the guiding structure and plasma density on the propagation of waves are also presented

  20. Insights into the Mechanism of Type I Dehydroquinate Dehydratases from Structures of Reaction Intermediates

    Light, Samuel H.; Minasov, George; Shuvalova, Ludmilla; Duban, Mark-Eugene; Caffrey, Michael; Anderson, Wayne F.; Lavie, Arnon (NWU); (UIC)

    2012-02-27

    The biosynthetic shikimate pathway consists of seven enzymes that catalyze sequential reactions to generate chorismate, a critical branch point in the synthesis of the aromatic amino acids. The third enzyme in the pathway, dehydroquinate dehydratase (DHQD), catalyzes the dehydration of 3-dehydroquinate to 3-dehydroshikimate. We present three crystal structures of the type I DHQD from the intestinal pathogens Clostridium difficile and Salmonella enterica. Structures of the enzyme with substrate and covalent pre- and post-dehydration reaction intermediates provide snapshots of successive steps along the type I DHQD-catalyzed reaction coordinate. These structures reveal that the position of the substrate within the active site does not appreciably change upon Schiff base formation. The intermediate state structures reveal a reaction state-dependent behavior of His-143 in which the residue adopts a conformation proximal to the site of catalytic dehydration only when the leaving group is present. We speculate that His-143 is likely to assume differing catalytic roles in each of its observed conformations. One conformation of His-143 positions the residue for the formation/hydrolysis of the covalent Schiff base intermediates, whereas the other conformation positions the residue for a role in the catalytic dehydration event. The fact that the shikimate pathway is absent from humans makes the enzymes of the pathway potential targets for the development of non-toxic antimicrobials. The structures and mechanistic insight presented here may inform the design of type I DHQD enzyme inhibitors.

  1. Characteristics of core promoter types with respect to gene structure and expression in Arabidopsis thaliana.

    Yamamoto, Yoshiharu Y; Yoshioka, Yohei; Hyakumachi, Mitsuro; Obokata, Junichi

    2011-10-01

    It is now well known that vertebrates use multiple types of core promoter to accomplish differentiated tasks in Pol II-dependent transcription. Several transcriptional characteristics are known to be associated with core types, including distribution patterns of transcription start sites (TSSs) and selection between tissue-specific and constitutive expression profiles. However, their relationship to gene structure is poorly understood. In this report, we carried a comparative analysis of three Arabidopsis core types, TATA, GA, and Coreless, with regard to gene structure. Our genome-wide investigation was based on the peak TSS positions in promoters that had been identified in a large-scale experimental analysis. This analysis revealed that the types of core promoter are related with the room for promoters that is measured as the distance from the TSS to the end of the upstream gene, the distance from the TSS to the start position of the coding sequence (CDS), and the number and species of the cis-regulatory elements. Of these, it was found that the distance from the TSS to the CDS has a tight, inverse correlation to the expression level, and thus the observed relationship to the core type appears to be indirect. However, promoter length and preference of cis-elements are thought to be a direct reflection of core type-specific transcriptional initiation mechanisms. PMID:21745829

  2. Appurtenance Influence on Type III Hanford Single-Shell Tank Structural Integrity - 12255

    The interim stabilized Hanford Single-Shell Tanks (SSTs) are currently undergoing a state of the art analysis to assess the structural integrity of the waste storage tanks, for cleanup and closure operations, considering their adverse thermal histories and an updated seismic hazard for the Hanford Site near Richland, Washington. The SSTs contain a variety of ancillary pits, piping, piping supports, risers, equipment, and penetrations known as appurtenances. These appurtenances may alter the structural response and ultimately could affect the structural integrity of the SSTs. An important challenge to the structural analysis of the SSTs is to determine the impact of these appurtenances on structural integrity. To achieve this, the various appurtenances were reviewed and a bounding appurtenance configuration for the SST Type III tanks was analyzed using finite element models for both thermal and operating loads as well as seismic loads. Tank structural demands from the finite element analyses were evaluated according to American Concrete Institute (ACI-349) code requirements to determine the tank structural integrity. The appurtenances configuration is found to increase the demand to capacity ratios in local regions near the appurtenances. Away from the appurtenances the influence on structural integrity is minor. The ACI-349-06 evaluation of the Type III SST bounding appurtenance configuration shows the tank is still structurally sound under all evaluated load combinations. When the appurtenance model D/C ratios were compared to those from the baseline axisymmetric model it was found that there were significant differences in the results, particularly under seismic loading conditions. This indicates that the effect of appurtenances on tank structural integrity should at least be considered in all SST AORs. (authors)

  3. An Investigation on the Morphological Structure of IC59: A New Type of Morphology of BRCs?

    Miao, Jingqi; White, Glenn J; Nelson, Richard P

    2010-01-01

    With references to recent observational results on the nebula IC59, we applied our previously developed Smoothed Particle Hydrodynamics (SPH) code which is based on Radiative Driven Implosion (RDI) model, to investigate the possible formation mechanism for the observed morphological structures of differently shaped BRCs. The simulation results confirmed the existence of the 4th type morphology of BRCs -- type M BRC. We are able to find the necessary condition for the appearance of the type M BRC based on the fact that the simulated physical properties of the cloud are consistent with observations on IC59. More importantly, the prospect of RDI triggered star formation by RDI model in all of the observed type M BRCs is ruthlessly eliminated.

  4. Mesothelin, Stereocilin, and Otoancorin are predicted to have superhelical structures with ARM-type repeats

    Pastan Ira

    2009-01-01

    Full Text Available Abstract Background Mesothelin is a 40 kDa protein present on the surface of normal mesothelial cells and overexpressed in many human tumours, including mesothelioma and ovarian and pancreatic adenocarcinoma. It forms a strong and specific complex with MUC16, which is also highly expressed on the surface of mesothelioma and ovarian cancer cells. This binding has been suggested to be the basis of ovarian cancer metastasis. Knowledge of the structure of this protein will be useful, for example, in building a structural model of the MUC16-mesothelin complex. Mesothelin is produced as a precursor, which is cleaved by furin to produce the N-terminal half, which is called the megakaryocyte potentiating factor (MPF, and the C-terminal half, which is mesothelin. Little is known about the function of mesothelin and there is no information on its possible three-dimensional structure. Mesothelin has been reported to be homologous to the deafness-related inner ear proteins otoancorin and stereocilin, for neither of which the three-dimensional structure is known. Results The BLAST and PSI-BLAST searches confirmed that mesothelin and mesothelin precursor proteins are remotely homologous to stereocilin and otoancorin and more closely homologous to the hypothetical protein MPFL (MPF-like. Secondary structure prediction servers predicted a predominantly helical structure for both mesothelin and mesothelin precursor proteins and also for stereocilin and otoancorin. Three-dimensional structure prediction servers INHUB and I-TASSER produced structural models for mesothelin, which consisted of superhelical structures with ARM-type repeats in conformity with the secondary structure predictions. Similar ARM-type superhelical repeat structures were predicted by 3D-PSSM server for mesothelin precursor and for stereocilin and otoancorin proteins. Conclusion The mesothelin superfamily of proteins, which includes mesothelin, mesothelin precursor, megakaryocyte potentiating factor, MPFL, stereocilin and otoancorin, are predicted to have superhelical structures with ARM-type repeats. We suggest that all of these function as superhelical lectins to bind the carbohydrate moieties of extracellular glycoproteins.

  5. Hydrogen position, hydrogen bonding and hydroxide dynamics in the Cd(OH)Cl structure type

    Complete text of publication follows. The crystal structure of Cd(OH)Cl is already known since the single-crystal and powder diffraction investigations by Hoard and Grenko (1). It crystallizes in its own structure type which is intimately related to the layer structures of cadmium hydroxide and cadmium chloride. Although the isotypic structures of Ca(OH)Cl (2) and Sr(OH)Cl (3) have been examined, the hydrogen position of this structure type, however, is not yet completely clear. We performed single crystal diffraction of Cd(OH)Cl on a modern ?-CCD diffractometer, TOF neutron powder diffraction experiments with an annular cylindrical sample of Cd(OD)Cl, temperature dependent 2H-NMR-spectroscopy and quantum mechanical calculations to reinvestigate the crystal structure with full information about H-position, H-bonding and hydroxide dynamics. The results show that the hydrogen position is near a three-fold axis, that only small angle liberations occur and the amount of hydrogen bonding can be neglected. (author)

  6. Production of fine structures in type III solar radio bursts due to turbulent density profiles

    Magnetic reconnection events in the corona release energetic electron beams along open field lines, and the beams generate radio emission at multiples of the electron plasma frequency fp to produce type III solar radio bursts. Type III bursts often exhibit irregularities in the form of flux modulations with frequency and/or local temporal advances and delays, and a type IIIb burst represents the extreme case where a type III burst is fragmented into a chain of narrowband features called striae. Remote and in situ spacecraft measurements have shown that density turbulence is ubiquitous in the corona and solar wind, and often exhibits a Kolmogorov power spectrum. In this work, we numerically investigate the effects of one-dimensional macroscopic density turbulence (along the beam direction) on the behavior of type III bursts, and find that this turbulence produces stria-like fine structures in the dynamic spectra of both fp and 2 fp radiation. Spectral and temporal fine structures in the predicted type III emission are produced by variations in the scattering path lengths and group speeds of radio emission, and in the locations and sizes of emitting volumes. Moderate turbulence levels yield flux enhancements with much broader half-power bandwidths in fp than 2 fp emission, possibly explaining the often observed type IIIb-III harmonic pairs as being where intensifications in 2 fp radiation are not resolved observationally. Larger turbulence levels producing trough-peak regions in the plasma density profile may lead to broader, resolvable intensifications in 2 fp radiation, which may account for the type IIIb-IIIb pairs that are sometimes observed.

  7. Impact of varying soil structure on transport processes in different diagnostic horizons of three soil types.

    Kodesová, Radka; Vignozzi, Nadia; Rohosková, Marcela; Hájková, Tereza; Kocárek, Martin; Pagliai, Marcello; Kozák, Josef; Simůnek, Jirka

    2009-02-16

    When soil structure varies in different soil types and the horizons of these soil types, it has a significant impact on water flow and contaminant transport in soils. This paper focuses on the effect of soil structure variations on the transport of pesticides in the soil above the water table. Transport of a pesticide (chlorotoluron) initially applied on soil columns taken from various horizons of three different soil types (Haplic Luvisol, Greyic Phaeozem and Haplic Cambisol) was studied using two scenarios of ponding infiltration. The highest infiltration rate and pesticide mobility were observed for the Bt(1) horizon of Haplic Luvisol that exhibited a well-developed prismatic structure. The lowest infiltration rate was measured for the Bw horizon of Haplic Cambisol, which had a poorly developed soil structure and a low fraction of large capillary pores and gravitational pores. Water infiltration rates were reduced during the experiments by a soil structure breakdown, swelling of clay and/or air entrapped in soil samples. The largest soil structure breakdown and infiltration decrease was observed for the Ap horizon of Haplic Luvisol due to the low aggregate stability of the initially well-aggregated soil. Single-porosity and dual-permeability (with matrix and macropore domains) flow models in HYDRUS-1D were used to estimate soil hydraulic parameters via numerical inversion using data from the first infiltration experiment. A fraction of the macropore domain in the dual-permeability model was estimated using the micro-morphological images. Final soil hydraulic parameters determined using the single-porosity and dual-permeability models were subsequently used to optimize solute transport parameters. To improve numerical inversion results, the two-site sorption model was also applied. Although structural changes observed during the experiment affected water flow and solute transport, the dual-permeability model together with the two-site sorption model proved to be able to approximate experimental data. PMID:19062128

  8. High-pressure structural investigation of several zircon-type orthovanadates

    Errandonea, D; Ruiz-Fuertes, J; Segura, A; Achary, S N; Tyagi, A K; 10.1103/PhysRevB.79.184104

    2010-01-01

    Room temperature angle-dispersive x-ray diffraction measurements on zircon-type EuVO4, LuVO4, and ScVO4 were performed up to 27 GPa. In the three compounds we found evidence of a pressure-induced structural phase transformation from zircon to a scheelite-type structure. The onset of the transition is near 8 GPa, but the transition is sluggish and the low- and high-pressure phases coexist in a pressure range of about 10 GPa. In EuVO4 and LuVO4 a second transition to a M-fergusonite-type phase was found near 21 GPa. The equations of state for the zircon and scheelite phases are also determined. Among the three studied compounds, we found that ScVO4 is less compressible than EuVO4 and LuVO4, being the most incompressible orthovanadate studied to date. The sequence of structural transitions and compressibilities are discussed in comparison with other zircon-type oxides.

  9. The structure of the R8 term in type IIB string theory

    Based on the structure of the on-shell linearized superspace of type IIB supergravity, we argue that there is a non-BPS 16 derivative interaction in the effective action of type IIB string theory of the form (t8t8R4)2, which we call the R8 interaction. It lies in the same supermultiplet as the G8R4 interaction. Using the Kawai–Lewellen–Tye relation, we analyze the structure of the tree level eight-graviton scattering amplitude in the type IIB theory, which leads to the R8 interaction at the linearized level. This involves an analysis of color-ordered multi-gluon disc amplitudes in the type I theory, which shows an intricate pole structure and transcendentality consistent with various other interactions. Considerations of S-duality show that the R8 interaction receives non-analytic contributions in the string coupling at one and two loops. Apart from receiving perturbative contributions, we show that the R8 interaction receives a non-vanishing contribution in the one D-instanton-anti-instanton background at leading order in the weak coupling expansion. (paper)

  10. A new tetragonal structure type for Li2B2C.

    Pavlyuk, Volodymyr; Milashys, Viktoriya; Dmytriv, Grygoriy; Ehrenberg, Helmut

    2015-01-01

    The ternary dilithium diboron carbide, Li2B2C (tetragonal, space group P-4m2, tP10), crystallizes as a new structure type and consists of structural fragments which are typical for structures of elemental lithium and boron or binary borocarbide B13C2. The symmetries of the occupied sites are .m. and 2mm. for the B and C atoms, and -4m2 and 2mm. for the Li atoms. The coordination polyhedra around the Li atoms are cuboctahedra and 15-vertex distorted pseudo-Frank-Kasper polyhedra. The environment of the B atom is a ten-vertex polyhedron. The nearest neighbours of the C atom are two B atoms, and this group is surrounded by a deformed cuboctahedron with one centred lateral facet. Electronic structure calculations using the TB-LMTO-ASA method reveal strong B...C and B...B interactions. PMID:25567573

  11. Crystal structure of the Yersinia type III secretion protein YscE

    Phan, Jason; Austin, Brian P.; Waugh, David S. (NIH)

    2010-12-06

    The plague-causing bacterium Yersinia pestis utilizes a contact-dependent (type III) secretion system (T3SS) to transport virulence factors from the bacterial cytosol directly into the interior of mammalian cells where they interfere with signal transduction pathways that mediate phagocytosis and the inflammatory response. The type III secretion apparatus is composed of 20-25 different Yersinia secretion (Ysc) proteins. We report here the structure of YscE, the smallest Ysc protein, which is a dimer in solution. The probable mode of oligomerization is discussed.

  12. THE INFLUENCES OF THE SLAB DISCONTINUITIES ON THE INTERNAL FORCES, AT FRAME TYPE REINFORCED CONCRETE STRUCTURES

    Mehmet TERZİ

    2006-03-01

    Full Text Available To resist earthquake forces in a confidential manner is one of the fundamental requirements of the structural system design of buildings. The main principles of Earthquake-resistant design of buildings have the symetric plan and regular configuration of the structural system. Regular buildings are easier in application, for designing, dimensioning of structural elements and much more economic for consruction cost. Also, the results of the structural system analysis of regular buildings represent the behaviour of the real structure. For these reasons, regular buildings are prefered for the best building design and analysis. Vertical and horizontal discontinuities in building structures, instant stiffness changes and variation of mass distribution are negative states, display good seismic behaviour. The buildings having irregularities in plan and in elevation are accepted as non-regular buildings. In practise, non-regular buildings are not economic in construction cast, lead to stress concentrations hazardous to the structure and causing erroneous application. If the basic methods of structural analysis for regular buildings are applied to non-regular buildings the effects of irregularities must be considered. Analysis of the regular frame type structural systems according to The Turkish earthquake code is performed on a lineer elastic model assuming different cavity ratios of the floor slab by using SAP2000 Structural Analysis Programme applying simplified modal response spectrum analysis methods. Numerical results of the internal forces of the elements of the structural system are obtained and compared for two different casses in one case the floor diaphragms are sufficiently rigid in their plane, in the other case unsuffiently rigid in their plane.

  13. Synthesis and crystal structure of three silver indium double phosphates

    Strelkov, M. A.; Zhizhin, M. G.; Komissarova, L. N.

    2006-12-01

    Three new silver indium double phosphates Ag 3In(PO 4) 2 (I), β-(II) and α-Ag 3In 2(PO 4) 3 (III) were synthesized by solid state method (I and II—700 °C, III—900 °C). Compounds I and II crystallize into a monoclinic system (I—sp. gr. C2/ m, Z=2, a=8.7037(1)Å, b=5.4884(1)Å, c=7.3404(1)Å, β=93.897(1)°; II—sp. gr. C2/ c, Z=4, a=12.6305(1)Å, b=12.8549(1)Å, c=6.5989(1)Å, β=113.842(1)°), and compound III crystallize into a hexagonal system (sp. gr. R-3 c, Z=6, a=8.9943(1)Å, c=22.7134(1)Å). Their crystal structures were determined by the Rietveld analysis (I— R=6.47, R=8.54; II— R=5.67, R=6.40; III— R=7.30, R=9.91). Structure of Ag 3In(PO 4) 2 is related to the sodium chromate structure type and is isotypic to α-Na 3In(PO 4) 2. The polymorphous modifications of β- and α-Ag 3In 2(PO 4) 3 are isostructural to sodium analogs ( β- and α-Na 3In 2(PO 4) 3) and are related to alluaudite (II) and NASICON (III) structure types. Compounds I and II are not stable at temperature above 850 °C. Ag 3In(PO 4) 2 is decomposed providing silver orthophosphate Ag 3PO 4 and α-Ag 3In 2(PO 4) 2. β-Ag 3In 2(PO 4) 3 is transformed to α-Ag 3In 2(PO 4) 3.

  14. Band stop vibration suppression using a passive X-shape structured lever-type isolation system

    Liu, Chunchuan; Jing, Xingjian; Chen, Zhaobo

    2016-02-01

    In the paper, band-stop vibration suppression property using a novel X-shape structured lever-type isolation system is studied. The geometrical nonlinear property of an X-shape supporting structure is used to improve the band-stop characteristics in the low frequency range of the lever-type vibration isolator. With the dynamics modeling of this hybrid structural system, it is shown that the proposed hybrid vibration system has very beneficial nonlinear stiffness and damping properties which are helpful to achieve much wider stop bandwidth. Theoretical results demonstrate that the anti-resonant frequencies, width and magnitude of the stop band can all be flexibly designed with structural parameters, and the parameters of the X-shape supporting structure are very critical for designing the band-stop frequency to achieve excellent low-frequency isolation performance. The results in the study provide a new approach to the design of the passive vibration suppression system in the low frequency region.

  15. Identify Structural Flaw Location and Type with an Inverse Algorithm of Resonance Inspection

    Xu, Wei; Lai, Canhai; Sun, Xin

    2015-10-20

    To evaluate the fitness-for-service of a structural component and to quantify its remaining useful life, aging and service-induced structural flaws must be quantitatively determined in service or during scheduled maintenance shutdowns. Resonance inspection (RI), a non-destructive evaluation (NDE) technique, distinguishes the anomalous parts from the good parts based on changes in the natural frequency spectra. Known for its numerous advantages, i.e., low inspection cost, high testing speed, and broad applicability to complex structures, RI has been widely used in the automobile industry for quality inspection. However, compared to other contemporary direct visualization-based NDE methods, a more widespread application of RI faces a fundamental challenge because such technology is unable to quantify the flaw details, e.g. location, dimensions, and types. In this study, the applicability of a maximum correlation-based inverse RI algorithm developed by the authors is further studied for various flaw cases. It is demonstrated that a variety of common structural flaws, i.e. stiffness degradation, voids, and cracks, can be accurately retrieved by this algorithm even when multiple different types of flaws coexist. The quantitative relations between the damage identification results and the flaw characteristics are also developed to assist the evaluation of the actual state of health of the engineering structures.

  16. Height of transfer unit determination at hydrogen isotopic distillation on B7 type structured packing

    Due to the low pressure drop that it introduces, the structured packing is often used in the case of distillation under vacuum and of the mixture separation when the desired component is found in very low concentration, for example the water, hydrogen and oxygen isotopic distillation. The paper presents a model for the determination of height of transfer unit at hydrogen isotopic distillation plant with structured B7 type packing. The values of HTU calculated with the analogy model between the heat, momentum and mass transfer are compared with the experimental data. (authors)

  17. Determination of height of transfer unit at hydrogen isotopic distillation on B7 type structured packing

    Due to the low pressure drop which that the structured packing introduces it is often used in the case of distillations under vacuum and of the mixture separation when the desired component is present in very low concentration, for example the water, hydrogen and oxygen isotopic distillation. The paper presents a model for the determination of height of transfer unit at hydrogen isotopic distillation plant with structured B7 type packing. The values of HTU calculated with the analogy model between the heat, momentum and mass transfer are compared with the experimental data. (authors)

  18. Height of transfer unit determination at hydrogen isotopic distillation on structured packing, B7 type

    Due to the low pressure drop that it introduces, the structured packing is often used in the case of distillations under vacuum and of the mixture separation when the desired component is founded in very low concentration, for example the water, hydrogen and oxygen isotopic distillation. The paper presents a model for the determination of height of transfer unit at hydrogen isotopic distillation plant with structured B7 type packing. The values of the height of a transfer unit (HTU) calculated with the analogy model between the heat, momentum and mass transfer are compared with the experimental data

  19. Structure of the Myotonic Dystrophy Type 2 RNA and Designed Small Molecules That Reduce Toxicity

    Childs-Disney, Jessica L.; Yildirim, Ilyas; Park, HaJeung; Lohman, Jeremy R.; Guan, Lirui; Tran, Van Tuan; Sarkar, Partha; Schatz, George C.; Disney, Matthew D.

    2013-01-01

    Myotonic dystrophy type 2 (DM2) is an untreatable neuromuscular disorder caused by a r(CCUG) expansion (r(CCUG)exp) that folds into an extended hairpin with periodically repeating 2×2 nucleotide internal loops (5’CCUG/3’GUCC). We designed multivalent compounds that improve DM2-associated defects using information about RNA-small molecule interactions. We also report the first crystal structure of r(CCUG)exp refined to 2.35 Å. Structural analysis of the three 5’CCUG/3’GUCC repeat internal loop...

  20. Asymptotics of Smallest Component Sizes in Decomposable Combinatorial Structures of Alg-Log Type

    Dong, Li; Gao, Zhicheng; Panario, Daniel; Richmond, Bruce

    2010-01-01

    A decomposable combinatorial structure consists of simpler objects called components which by thems elves cannot be further decomposed. We focus on the multi-set construction where the component generating function C(z) is of alg-log type, that is, C(z) behaves like c + d(1 -z/rho)(alpha) (ln1/1-z/rho)(beta) (1 + o(1)) when z is near the dominant singularity rho. We provide asymptotic results about the size of thes mallest components in random combinatorial structures for the cases 0 < alpha ...

  1. Structure prediction of P1-type ATPases and molecular dynamics simulations on their Metal Binding Domains

    Arumugam, Karthik

    2009-01-01

    P1-type ATPases are a special kind of ATP driven pumps which transport soft heavy metals (Cu+, Zn2+, Pb2+ Cd2+) across the cell membranes. Their complete structure is, in general, unknown. We are interested in the structure and dynamics of the transmembrane part of the Cadmium ATPase (CadA) and the metal binding domains of the human Copper transporting Menkes ATPase. Sequence similarity and hydropathy analyses, completed by experiments have shown that soft metal pumps are constituted of 8 tra...

  2. Optical properties of crystals with incommensurate structure of Lifshitzs type

    O.G.Vlokh

    2000-09-01

    Full Text Available A review of optical properties of A2BX4 group crystals with incommensurate modulated structure of Lifshitzs type a.i. crystals, which characterize nonequitranslation unit cell of high temperature and ordering - low temperature phases is done. The characteristics features of birefringence, optical activity, light absorption and the effects induced by the external influences (temperature, pressure, electric fields and mechanical stresses, X-ray radiation, as well as their gradients are considered in this paper. It is shown that different types of interaction between defects or impurities and structural elements (pinning, viscous interaction, nucleation and annihilation of phase solitons or commensurate-incommensurate states (so-called discommensuration manifest themselves in the anomalies of optical phenomena in the incommensurate phases.

  3. Real non-abelian mixed Hodge structures for schematic homotopy types of quasi-projective varieties

    Pridham, J P

    2011-01-01

    The relative Malcev homotopy type of a quasi-projective variety carries a canonical non-positively weighted algebraic mixed twistor structure (MTS), provided we restrict to extensions of local systems with trivial monodromy around the components of the divisor. This can be enriched to an analytic mixed Hodge structure (MHS), which becomes algebraic if we restrict to extensions of local systems underlying VHS. We then show that every non-positively weighted MHS or MTS on homotopy types admits a canonical splitting over SL_2. For smooth varieties, this allows us to characterise the MHS or MTS in terms of the Gysin spectral sequence, together with the monodromy action at the Archimedean place. It also means that the relative Malcev homotopy groups carry canonical MTS or MHS.

  4. Structural Comparison of n-type and p-type LaAlO3/SrTiO3 Interfaces

    Bell, Christopher

    2011-08-19

    Using a surface x-ray diffraction technique, we investigated the atomic structure of two types of interfaces between LaAlO{sub 3} and SrTiO{sub 3}, that is, p-type (SrO/AlO{sub 2}) and n-type (TiO{sub 2}/LaO) interfaces. Our results demonstrate that the SrTiO{sub 3} in the sample with the n-type interface has a large polarized region, while that with the p-type interface has a limited polarized region. In addition, the atomic intermixing was observed to extend deeper into STO substrate at the n-type interface than at the p-type. These differences result in different degrees of band bending, which likely contributes to the striking difference in electrical conductivity between the two types of interfaces.

  5. Crystal Structure of a Putative HTH-Type Transcriptional Regulator yxaF from Bacillus subtilis

    Seetharaman,J.; Kumaran, D.; Bonanno, J.; Burley, S.; Swaminathan, S.

    2006-01-01

    The New York Structural GenomiX Research Consortium (NYSGXRC) has selected the protein coded by yxaF gene from Bacillus subtilis as a target for structure determination. The yxaF protein has 191 residues with a molecular mass of 21 kDa and had no sequence homology to any structure in the Protein Data Bank (PDB) at the time of target selection. We aimed to elucidate the three-dimensional structure for the putative protein yxaF to better understand the relationship between protein sequence, structure, and function. This protein is annotated as a putative helix-turn-helix (HTH) type transcriptional regulator. Many transcriptional regulators like TetR and QacR use a structurally well-defined DNA-binding HTH motif to recognize the target DNA sequences. DNA-HTH motif interactions have been extensively studied. As the HTH motif is structurally conserved in many regulatory proteins, these DNA-protein complexes show some similarity in DNA recognition patterns. Many such regulatory proteins have a ligand-binding domain in addition to the DNA-binding domain. Structural studies on ligand-binding regulatory proteins provide a wealth of information on ligand-, and possibly drug-, binding mechanisms. Understanding the ligand-binding mechanism may help overcome problems with drug resistance, which represent increasing challenges in medicine. The protein encoded by yxaF, hereafter called T1414, shows fold similar to QacR repressor and TetR/CamR repressor and possesses putative DNA and ligand-binding domains. Here, we report the crystal structure of T1414 and compare it with structurally similar drug and DNA-binding proteins.

  6. Crystal Structure of a Putative HTH-Type Transcriptional Regulator yxaF from Bacillus subtilis

    The New York Structural GenomiX Research Consortium (NYSGXRC) has selected the protein coded by yxaF gene from Bacillus subtilis as a target for structure determination. The yxaF protein has 191 residues with a molecular mass of 21 kDa and had no sequence homology to any structure in the Protein Data Bank (PDB) at the time of target selection. We aimed to elucidate the three-dimensional structure for the putative protein yxaF to better understand the relationship between protein sequence, structure, and function. This protein is annotated as a putative helix-turn-helix (HTH) type transcriptional regulator. Many transcriptional regulators like TetR and QacR use a structurally well-defined DNA-binding HTH motif to recognize the target DNA sequences. DNA-HTH motif interactions have been extensively studied. As the HTH motif is structurally conserved in many regulatory proteins, these DNA-protein complexes show some similarity in DNA recognition patterns. Many such regulatory proteins have a ligand-binding domain in addition to the DNA-binding domain. Structural studies on ligand-binding regulatory proteins provide a wealth of information on ligand-, and possibly drug-, binding mechanisms. Understanding the ligand-binding mechanism may help overcome problems with drug resistance, which represent increasing challenges in medicine. The protein encoded by yxaF, hereafter called T1414, shows fold similar to QacR repressor and TetR/CamR repressor and possesses putative DNA and ligand-binding domains. Here, we report the crystal structure of T1414 and compare it with structurally similar drug and DNA-binding proteins

  7. Crystal structures and luminescent properties of lanthanide nitrate coordination polymers with structurally related amide type bridging podands

    A one-dimensional linear chain coordination polymer [ErLI(NO3)3(CH3CO2Et)]n (LI=1,2-bis{[(2'-furfurylaminoformyl)phenoxyl]methyl}benzene) and a one-dimensional zig-zag coordination polymer {[TbLII(NO3)3(H2O)].(H2O)}n (LII=1,2-bis{[2'-(2-pyridylmethylaminoformyl)phenoxyl]methyl}benzene) were assembled by two structurally related bridging podands LI and LII which have uniform skeleton and different terminal groups. In {[TbLII(NO3)3(H2O)].(H2O)}n, the neutral chains were linked by the hydrogen bonding interactions between the free and coordinated water molecules from two different directions to interpenetrate into a 3D supramolecular structure. At the same time, the luminescent properties of the solid Tb(III) nitrate complexes of these podands were investigated at room temperature. The lowest triplet state energy levels T1 of the podands LI and LII indicate that the triplet state energy levels of the antennae are both above the lowest excited resonance level of 5D4 of Tb3+ ion. Thus the absorbed energy could be transferred from ligands to the central Tb3+ ions. And the influence of the hydrogen bonding on the luminescence efficiencies of the coordination polymers was also discussed. -- Graphical Abstract: Two one-dimensional lanthanide coordination polymers were assembled by two structurally related bridging podands, and the effects of the structures on luminescent properties of the solid Tb(III) nitrate complexes were investigated. Display Omitted Research Highlights: → Two structurally related amide type bridging ligands were designed and synthesized. → Two one dimensional lanthanide nitrate coordination polymers were obtained. → The structure effects on luminescent properties of the terbium complexes were discussed.

  8. Rosuvastatin Alleviates Type 2 Diabetic Atrial Structural and Calcium Channel Remodeling.

    Pan, Yilong; Li, Bin; Wang, Jingzhuo; Li, Xiaodong

    2016-01-01

    Recent evidence has indicated that type 2 diabetes mellitus is related to an increased risk of atrial arrhythmias, which might result from atrial structural and electrical remodeling. Inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase (statins), known as lipid-lowering agents, have been shown to exert antiarrhythmic effects both in experimental models and in humans. In this study, we postulate that atrial structural and calcium channel remodeling may occur in streptozotocin-induced type 2 diabetic rats and can be alleviated by rosuvastatin (RSV) therapy. We randomly divided Wistar rats into control, untreated diabetic, RSV-treated control, and RSV-treated diabetic animals. After treatment with RSV for 4 weeks, rats were assessed by metabolic tests, histopathology, and transmission electron microscopy. The expression of Cav1.2, Cav3.1, and Cav3.2 in atrial tissues was detected by real-time reverse transcriptase polymerase chain reaction and Western blot, and inward calcium currents (lCa-L and lCa-T) were recorded in isolated atrial myocytes using patch-clamp techniques. Compared with controls, diabetic rats displayed severe metabolic disorders and a disorganized cellular ultrastructure. In diabetic rats, the expression of Cav1.2 mRNA and protein was significantly decreased, whereas that of Cav3.1 was significantly increased. Long-term RSV treatment partially relieved some pathological changes in diabetic rats. However, Cav3.2 mRNA and protein remained unchanged in control and diabetic groups and was unaffected by RSV. Diabetic atrial myocytes showed significantly reduced L-type but increased T-type, Ca currents, and this effect was significantly reversed by RSV. In conclusion, long-term RSV therapy can alleviate structural and calcium channel remodeling in the type 2 diabetic rat atrium. PMID:26335222

  9. Physicochemical and structural characteristics of HEU-type zeolitic tuff treated by hydrochloric acid

    MAGDALENA TOMASEVIC-CANOVIC; JOVAN LEMIC; ALEKSANDRA DAKOVIC; VERA DONDUR; ANA RADOSAVLJEVIC-MIHAJLOVIC

    2004-01-01

    Samples of natural HEU-type zeolites clinoptilolite-Ca, from the Novakovici deposit (near Prijedor, Bosnia and Herzegovina) were treated with the hydrochloric acid of various concentrations (from 10-3 M to 2 M). Zeolitic tuffs before and after the acid treatment were examined using IR, XRPD, and chemical analyses. The changes in the crystal structure of acid treated samples showed a significant reduction in the crystallinity of zeolitic tuffs (6070 %), which were effected by hydrochloric aci...

  10. The Structure of Parental Involvement and Relations to Disease Management for Youth with Type 1 Diabetes

    Palmer, Debra L.; Osborn, Peter; King, Pamela S.; Berg, Cynthia A.; Butler, Jorie; Butner, Jonathan; Horton, Dwayne; Wiebe, Deborah J.

    2010-01-01

    Objective To test structural models of parental involvement in type 1 diabetes and to examine associations of parental involvement with adherence and metabolic control. Methods Two hundred and fifty-two young adolescents (10–14 years) completed reports of adherence and parents’ involvement: acceptance, independence encouragement, communication, general and diabetes-specific monitoring, frequency of help, and intrusive support. HbA1c values came from medical records. Results A model of relatio...

  11. Family Capitalism vs. Capitalism of Agents A Leontief-type Model of Ownership Structures

    František Turnovec

    2001-01-01

    A simple algebraic model of a property structure leading to the Leontief's input-output scheme is developed and used to eliminate indirect ownership relations and evaluate the fmal distribution of national property among individual owners. Concepts of "family capitalism" and "capitalism of agents" type of corporate governance are defmed and compared. Implications of different designs of corporate governance for general equilibrium theory, profit distribution and decision making are discussed.

  12. Optical properties of crystals with incommensurate structure of Lifshitz’s type

    O.G. Vlokh

    2000-01-01

    A review of optical properties of A2BX4 group crystals with incommensurate modulated structure of Lifshitz’s type a.i. crystals, which characterize nonequitranslation unit cell of high temperature and ordering - low temperature phases is done. The characteristics features of birefringence, optical activity, light absorption and the effects induced by the external influences (temperature, pressure, electric fields and mechanical stresses, X-ray radiation, as well as their gradients) are consid...

  13. Asymptotics of Decomposable Combinatorial Structures of Alg-Log Type With Positive Log Exponent

    Gao, Zhicheng; Laferrière, David; Panario, Daniel

    2010-01-01

    We consider the multiset construction of decomposable structures with component generating function C(z) of alg-log type, \\emphi.e., align* C(z) = (1-z)^-α (\\log 1 / 1-z)^β . align* We provide asymptotic results for the number of labeled objects of size n in the case when α is positive and β is positive and in the case α = 0 and β ≥2 . The case 0

  14. A Multilocus Sequence Typing Scheme Implies Population Structure and Reveals Several Putative Novel Achromobacter Species

    Spilker, Theodore; Vandamme, Peter; LiPuma, John J.

    2012-01-01

    The genus Achromobacter currently is comprised of seven species, including Achromobacter xylosoxidans, an opportunistic and nosocomial pathogen that displays broad-spectrum antimicrobial resistance and is recognized as causing chronic respiratory tract infection in persons with cystic fibrosis (CF). To enable strain typing for global epidemiologic investigations, to clarify the taxonomy of Achromobacter-like strains, and to elucidate the population structure of this genus, we developed a ge...

  15. GP3 is a structural component of the PRRSV type II (US) virion

    Glycoprotein 3 (GP3) is a highly glycosylated PRRSV envelope protein which has been reported as being present in the virions of PRRSV type I, while missing in the type II PRRSV (US) virions. We herein present evidence that GP3 is indeed incorporated in the virus particles of a North American strain of PRRSV (FL12), at a density that is consistent with the minor structural role assigned to GP3 in members of the Arterivirus genus. Two 15aa peptides corresponding to two different immunodominant linear epitopes of GP3 derived from the North American strain of PRRSV (FL12) were used as antigen to generate a rabbit monospecific antiserum to this protein. The specificity of this anti-GP3 antiserum was confirmed by radioimmunoprecipitation (RIP) assay using BHK-21 cells transfected with GP3 expressing plasmid, MARC-145 cells infected with FL12 PRRSV, as well as by confocal microscopy on PRRSV-infected MARC-145 cells. To test if GP3 is a structural component of the virion, 35S-labelled PRRSV virions were pelleted through a 30% sucrose cushion, followed by a second round of purification on a sucrose gradient (20-60%). Virions were detected in specific gradient fractions by radioactive counts and further confirmed by viral infectivity assay in MARC 145 cells. The GP3 was detected in gradient fractions containing purified virions by RIP using anti-GP3 antiserum. Predictably, the GP3 was less abundant in purified virions than other major structural envelope proteins such as GP5 and M. Further evidence of the presence of GP3 at the level of PRRSV FL12 envelope was obtained by immunogold staining of purified virions from the supernatant of infected cells with anti-GP3 antiserum. Taken together, these results indicate that GP3 is a minor structural component of the PRRSV type II (FL12 strain) virion, as had been previously described for PRRSV type I.

  16. Nonmetric Multidimensional Scaling Corrects for Population Structure in Association Mapping With Different Sample Types

    Zhu, Chengsong; Yu, Jianming

    2009-01-01

    Recent research has developed various promising methods to control for population structure in genomewide association mapping of complex traits, but systematic examination of how well these methods perform under different genetic scenarios is still lacking. Appropriate methods for controlling genetic relationships among individuals need to balance the concern of false positives and statistical power, which can vary for different association sample types. We used a series of simulated samples ...

  17. How similar is the stellar structure of low-mass late-type galaxies to that of early-type dwarfs?

    Janz, Joachim; Laine, Jarkko; Salo, Heikki; Lisker, Thorsten

    2016-01-01

    We analyse structural decompositions of 500 late-type galaxies (Hubble $T$-type $\\ge 6$) from the Spitzer Survey of Stellar Structure in Galaxies (S$^4$G), spanning a stellar mass range of about $10^7$ to a few times $10^{10}$ M$_\\odot$. Their decomposition parameters are compared with those of the early-type dwarfs in the Virgo cluster from Janz et al. They have morphological similarities, including the fact that the fraction of simple one-component galaxies in both samples increases towards lower galaxy masses. We find that in the late-type two-component galaxies both the inner and outer structures are by a factor of two larger than those in the early-type dwarfs, for the same stellar mass of the component. While dividing the late-type galaxies to low and high density environmental bins, it is noticeable that both the inner and outer components of late types in the high local galaxy density bin are smaller, and lie closer in size to those of the early-type dwarfs. This suggests that, although structural dif...

  18. Complex structure of type VI peptidoglycan muramidase effector and a cognate immunity protein

    The structure of the Tse3–Tsi3 complex associated with the bacterial type VI secretion system of P. aeruginosa has been solved and refined at 1.9 Å resolution. The structural basis of the recognition of the muramidase effector and its inactivation by its cognate immunity protein is revealed. The type VI secretion system (T6SS) is a bacterial protein-export machine that is capable of delivering virulence effectors between Gram-negative bacteria. The T6SS of Pseudomonas aeruginosa transports two lytic enzymes, Tse1 and Tse3, to degrade cell-wall peptidoglycan in the periplasm of rival bacteria that are competing for niches via amidase and muramidase activities, respectively. Two cognate immunity proteins, Tsi1 and Tsi3, are produced by the bacterium to inactivate the two antibacterial effectors, thereby protecting its siblings from self-intoxication. Recently, Tse1–Tsi1 has been structurally characterized. Here, the structure of the Tse3–Tsi3 complex is reported at 1.9 Å resolution. The results reveal that Tse3 contains a C-terminal catalytic domain that adopts a soluble lytic transglycosylase (SLT) fold in which three calcium-binding sites were surprisingly observed close to the catalytic Glu residue. The electrostatic properties of the substrate-binding groove are also distinctive from those of known structures with a similar fold. All of these features imply that a unique catalytic mechanism is utilized by Tse3 in cleaving glycosidic bonds. Tsi3 comprises a single domain showing a β-sandwich architecture that is reminiscent of the immunoglobulin fold. Three loops of Tsi3 insert deeply into the groove of Tse3 and completely occlude its active site, which forms the structural basis of Tse3 inactivation. This work is the first crystallographic report describing the three-dimensional structure of the Tse3–Tsi3 effector–immunity pair

  19. Complex structure of type VI peptidoglycan muramidase effector and a cognate immunity protein

    Wang, Tianyu [Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Ding, Jinjing; Zhang, Ying; Wang, Da-Cheng, E-mail: dcwang@ibp.ac.cn [Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101 (China); Liu, Wei, E-mail: dcwang@ibp.ac.cn [The Third Military Medical University, Chongqing 400038 (China); Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101 (China)

    2013-10-01

    The structure of the Tse3Tsi3 complex associated with the bacterial type VI secretion system of P. aeruginosa has been solved and refined at 1.9 resolution. The structural basis of the recognition of the muramidase effector and its inactivation by its cognate immunity protein is revealed. The type VI secretion system (T6SS) is a bacterial protein-export machine that is capable of delivering virulence effectors between Gram-negative bacteria. The T6SS of Pseudomonas aeruginosa transports two lytic enzymes, Tse1 and Tse3, to degrade cell-wall peptidoglycan in the periplasm of rival bacteria that are competing for niches via amidase and muramidase activities, respectively. Two cognate immunity proteins, Tsi1 and Tsi3, are produced by the bacterium to inactivate the two antibacterial effectors, thereby protecting its siblings from self-intoxication. Recently, Tse1Tsi1 has been structurally characterized. Here, the structure of the Tse3Tsi3 complex is reported at 1.9 resolution. The results reveal that Tse3 contains a C-terminal catalytic domain that adopts a soluble lytic transglycosylase (SLT) fold in which three calcium-binding sites were surprisingly observed close to the catalytic Glu residue. The electrostatic properties of the substrate-binding groove are also distinctive from those of known structures with a similar fold. All of these features imply that a unique catalytic mechanism is utilized by Tse3 in cleaving glycosidic bonds. Tsi3 comprises a single domain showing a ?-sandwich architecture that is reminiscent of the immunoglobulin fold. Three loops of Tsi3 insert deeply into the groove of Tse3 and completely occlude its active site, which forms the structural basis of Tse3 inactivation. This work is the first crystallographic report describing the three-dimensional structure of the Tse3Tsi3 effectorimmunity pair.

  20. Recent insights into structures and functions of C-type lectins in the immune system

    Drickamer, Kurt; Taylor, Maureen E

    2015-01-01

    The majority of the C-type lectin-like domains in the human genome likely to bind sugars have been investigated structurally, although novel mechanisms of sugar binding are still being discovered. In the immune system, adhesion and endocytic receptors that bind endogenous mammalian glycans are often conserved, while pathogen-binding C-type lectins on cells of the innate immune system are more divergent. Lack of orthology between some human and mouse receptors, as well as overlapping specificities of many receptors and formation of receptor hetero-oligomers, can make it difficult to define the roles of individual receptors. There is good evidence that C-type lectins initiate signalling pathways in several different ways, but this function remains the least well understood from a mechanistic perspective. PMID:26163333

  1. Damage identification in beam type structures based on statistical moment using a two step method

    Wang, Dansheng; Xiang, Wei; Zhu, Hongping

    2014-02-01

    This paper defines a novel damage index-strain statistical moment, and formulates the fourth strain statistical moment (FSSM) of beam-type structures under white noise excitation. Based on this newly defined strain statistical moment index and the least square optimization algorithm, a two-step damage identification method is proposed. This two-step method is operated like this: first use the difference curves of FSSMs before and after damage to locate damage elements; then for those identified damage elements, employ the model updating method based on the least square algorithm to assess their damage severity. Numerical studies on a simply supported beam and a two-span continuous beam are performed and the study results show that the newly defined index is effective to locate damages, even when the noise intensity is as high as 15 percent. Integrating with the least square-based model updating technique, the damage severities of beam-type structures can also be determined quantitatively. In this way, the proposed two-step method is verified and found to be capable of identifying damage positions and severities of beam-type structures and insensitive to measurement noise.

  2. Fine and superfine structure of Decameter-Hectometer type II burst on 2011 June 7

    Dorovskyy, V V; Konovalenko, A A; Brazhenko, A I; Panchenko, M; Poedts, S; Mykhaylov, V A

    2015-01-01

    The characteristics of the type II bursts with herringbone structure observed both by ground based radio telescopes (UTR-2, URAN-2) and spaceborn spectrometers (STEREO A-B) are discussed. The burst was recorded on 7 June, 2011 in the frequency band 3--33~MHz. It was characterized by extremely rich fine structure. The statistical analysis of more than 300 herringbone sub-bursts constituting the burst was performed separately for the positively (reverse) and negatively (forward) drifting sub-bursts. The sense and the degree of circular polarization of the herringbone sub-bursts were measured in the respectively wide frequency band (16--32~MHz). A second order fine frequency structure of the herringbone sub-bursts was firstly observed and processed. Using STEREO COR1 (A,B) and SOHO LASCO C2 images the direction and radial speed of the CME responsible for the studied type II burst were determined. The possible location of the type II burst source on the flank of the shock was found.

  3. THE EFFECTS OF SEX, TOPOLOGICAL STRUCTURE, AND TASK TYPE ON HYPERTEXT NAVIGATIONAL PERFORMANCE.

    Chang, Wen-Te; Chien, Yu-Hung

    2015-06-01

    Currently, almost all online materials use hyperlinks to provide users access to background, supplemental, or alternative information presented in context, greatly increasing the potential integration of information. However, a major problem is that people do not navigate hyperlinks effectively when the links become more topologically complex. Thus, identification of the variables that lead to navigational errors is necessary for the effective design of hyperlinks. Ninety-one participants (45 women, 46 men) were recruited for this experiment. All were college students and ranged in age from 19 to 23 yr. (M = 20.87, SD = 1.02). Navigational performance was examined in relation to sex, topological structure, and task type. A network topology with single-node task was superior to one with a linear topology under a single-node task condition, but equal to one with a linear topology under a multi-node task condition. Men navigated the linear topology with multi-node task and a network topology with a single-node task significantly faster than women, whereas no significant differences were observed under the other conditions. Sex interacted with topological structure and task type. This study extended the research in this domain by demonstrating an interactive effect among sex, topological structure, and task type on the navigational performance of users and can contribute to research regarding web page design. PMID:26057417

  4. Study of macroporous silicon electrochemical etching in 3D structured N type silicon substrates

    Kouassi, Sebastien; Gautier, Gael; Desplobain, Sebastien; Ventura, Laurent [Laboratoire de Microelectronique de Puissance, Universite Francois Rabelais Tours, 16 Rue Pierre et Marie Curie, 37071 Tours Cedex 2 (France)

    2011-06-15

    In this paper, the electrochemical etching of 3D n-type substrates is investigated. These types of 3D structures are of interest to increase the active surface of some systems. Our aim is to improve a MEMS (Micro-Electro Mechanical System) micro fuel cell power through total surface enhancement without any modification of the cell footprint. To reach this objective, we perform a gas diffusion layer using localized macro-porous silicon. The porous area total surface is improved through trench formation (before porous silicon etching). This is supposed to allow a better power to surface ratio for manufactured fuel cell. The Figure on the right hand side introduces the aimed MEMS based micro fuel cell. The geometrical parameters of the designed structures and the manufacturing process influence are presented. To perform 3D structures, two types of anisotropic etching techniques have been used, alkaline etching of silicon and deep reactive ion etching (DRIE). Additional steps such as a doping layer have been used to improve the results obtained with the initial micro-fabrication process. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Structure determination, electronic and optical properties of NaGe 2P 3O 12 and Cs 2GeP 4O 13

    Zhao, Dan; Xie, Zhi; Hu, Jian-Ming; Zhang, Hao; Zhang, Wei-long; Yang, Song-Lin; Cheng, Wen-Dan

    2009-03-01

    Two alkali-metal germanium phosphates, namely, NaGe 2P 3O 12 and Cs 2GeP 4O 13, have been synthesized by the solid-state reactions and their structures determined by single-crystal X-ray diffraction. The structure of NaGe 2P 3O 12 features a Nasicon-type structure, crystallizing in space group R3¯ with a = 8.109(2), c = 21.536(8) (Å), V = 1226.3(6) Å 3, Z = 6, R1 = 0.0383 and ωR = 0.0960; Cs 2GeP 4O 13 crystallizes in triclinic space group P1¯ with a = 9.420(3), b = 10.209(4), c = 12.407(4) (Å), α = 104.136(6), β = 108.132(5), γ = 95.338(6)°, V = 1081.0(7) Å 3, Z = 2, R1 = 0.0445 and ωR = 0.1117. Additionally, the calculations of band structure and density of states were performed with the density functional theory method for the title compounds. The results show that the solid-state compounds of NaGe 2P 3O 12 and Cs 2GeP 4O 13 are insulator with indirect band-gap of 3.529 and 3.888 eV, respectively.

  6. Inhibition Kinetics And Emodin Cocrystal Structure of a Type II Polyketide Ketoreductase

    Korman, T.P.; Tan, Y.-H.; Wong, J.; Luo, R.; Tsai, S.-C.

    2009-05-20

    Type II polyketides are a class of natural products that include pharmaceutically important aromatic compounds such as the antibiotic tetracycline and antitumor compound doxorubicin. The type II polyketide synthase (PKS) is a complex consisting of 5-10 standalone domains homologous to fatty acid synthase (FAS). Polyketide ketoreductase (KR) provides regio- and stereochemical diversity during the reduction. How the type II polyketide KR specifically reduces only the C9 carbonyl group is not well understood. The cocrystal structures of actinorhodin polyketide ketoreductase (actKR) bound with NADPH or NADP{sup +} and the inhibitor emodin were solved with the wild type and P94L mutant of actKR, revealing the first observation of a bent p-quinone in an enzyme active site. Molecular dynamics simulation help explain the origin of the bent geometry. Extensive screening for in vitro substrates shows that unlike FAS KR, the actKR prefers bicyclic substrates. Inhibition kinetics indicate that actKR follows an ordered Bi Bi mechanism. Together with docking simulations that identified a potential phosphopantetheine binding groove, the structural and functional studies reveal that the C9 specificity is a result of active site geometry and substrate ring constraints. The results lay the foundation for the design of novel aromatic polyketide natural products with different reduction patterns.

  7. Evidence of organic structures in Ediacara-type fossils and associated microbial mats

    Steiner, Michael; Reitner, Joachim

    2001-12-01

    Ediacara-type fossils represent a group of soft-bodied organisms, mainly known from imprints in Proterozoic coarse-grained siliciclastic sedimentary rocks. Circular compressions of Beltanelliformis brunsae and remains related to Ediacara-type fossils, such as Cucullus fraudulentus, and Mucuplagum primitivum are reported here in an organic mode of preservation from the Neoproterozoic Doushantuo and Liulaobei Formations of China. They can be interpreted as prokaryotic colonies. A charnid fossil with circular attachment disc and stalk, but torn-off frond, is documented in a three-dimensional and partly organic mode of preservation from the Neoproterozoic Ust-Pinega Formation (White Sea coast, Russia). According to their morphology and structure, the Charniidae are not regarded by us as pennatulaceans. Modern Myxobacteria illustrate that macroscopic size, complexity, and even compartmentalization can also be developed by prokaryotic colonies. Part of the Ediacara-type fossils may therefore represent prokaryotic colonies or symbiotic organisms involving prokaryotes. Finally, direct evidence indicates that biofilms with associated prokaryotic sheaths, preserved in both organic and pyritic fashion, form the wrinkled surfaces (“elephant skin”) that were preferentially colonized by Ediacara-type fossils. This finding supports previous interpretations, based on comparative morphological and sedimentological approaches, that ancient wrinkle structures were microbial mats.

  8. Excitonic transitions in highly efficient (GaIn)As/Ga(AsSb) type-II quantum-well structures

    The excitonic transitions of the type-II (GaIn)As/Ga(AsSb) gain medium of a “W”-laser structure are characterized experimentally by modulation spectroscopy and analyzed using microscopic quantum theory. On the basis of the very good agreement between the measured and calculated photoreflectivity, the type-I or type-II character of the observable excitonic transitions is identified. Whereas the energetically lowest three transitions exhibit type-II character, the subsequent energetically higher transitions possess type-I character with much stronger dipole moments. Despite the type-II character, the quantum-well structure exhibits a bright luminescence

  9. Rh3B2-x, new structure type of binary borides with triclinic symmetry

    New binary compound Rh3B2-x, x=0.167 crystallizing with its own structure type has been observed from the as cast alloys. The compound has a limited thermal stability range: it was found to decompose after annealing at 800oC for 20 days. The crystal structure was investigated by X-ray diffraction from two single crystals using different techniques: CAD-4 automatic diffractometer, a=5.470(2), b=6.816(3), c=9.068(4), α=110.74(3), β=94.81(3), γ=90.44(2), 107 refined parameters, R1=0.0418, wR2=0.1087 for 1223 reflections with I>2σ(Io), and BRUKER SMART AXS, a=5.483(4), b=6.818(6), c=9.072 (7), a=110.78(1), b=94.73(1), g=90.46(1), 107 refined parameters, R1=0.0401, wR2=0.0959 for 943 reflections with I>2σ(Io). The Rh3B2-x, structure (space group P1-bar , Pearson symbol aP30-1) is the first representative of structures with triclinic symmetry among binary borides and contains three different types of boron-boron aggregation: isolated boron atoms, B-B pairs and B6 chain fragments

  10. Molecular dynamics studies on the structural stability of wild-type dog prion protein.

    Zhang, Jiapu; Liu, David D W

    2011-06-01

    Prion diseases such as Creutzfeldt-Jakob disease, variant Creutzfeldt-Jakob diseases, Gerstmann-Sträussler-Scheinker syndrome, Fatal Familial Insomnia, Kuru in humans, scrapie in sheep, bovine spongiform encephalopathy (or 'mad-cow' disease) and chronic wasting disease in cattle are invariably fatal and highly infectious neurodegenerative diseases affecting humans and animals. However, by now there have not been some effective therapeutic approaches to treat all these prion diseases. In 2008, canine mammals including dogs (canis familials) were the first time academically reported to be resistant to prion diseases (Vaccine 26: 2601-2614 (2008)). Thus, it is very worth studying the molecular structures of dog prion protein to obtain insights into the immunity of dogs to prion diseases. This paper studies the molecular structural dynamics of wild-type dog prion protein. The comparison analyses with rabbit prion protein show that the dog prion protein has stable molecular structures whether under neutral or low pH environments. We also find that the salt bridges such as D177-R163 contribute to the structural stability of wild-type rabbit prion protein under neutral pH environment. PMID:21469747

  11. Four basic symmetry types in the universal 7-cluster structure of 143 complete bacterial genomic sequences

    Gorban, A N; Zinovyev, A Yu

    2011-01-01

    Coding information is the main source of heterogeneity (non-randomness) in the sequences of bacterial genomes. This information can be naturally modeled by analysing cluster structures in the "in-phase" triplet distributions of relatively short genomic fragments (200-400bp). We found a universal 7-cluster structure in bacterial genomic sequences and explained its properties. We show that codon usage of bacterial genomes is a multi-linear function of their genomic G+C-content with high accuracy. Based on the analysis of 143 completely sequenced bacterial genomes available in Genbank in August 2004, we show that there are four "pure" types of the 7-cluster structure observed. All 143 cluster animated 3D-scatters are collected in a database and is made available on our web-site: http://www.ihes.fr/~zinovyev/7clusters The finding can be readily introduced into any software for gene prediction, sequence alignment or bacterial genomes classification.

  12. Sloshing and fluid-structure interaction in a 400-MWe pool-type advanced fast reactor

    This paper describes the seismic analysis of a 400-MWe advanced fast reactor under 0.3 g SSE ground excitation. Two types of analyses are performed - the sloshing analysis and the fluid-structure interaction analysis. In the sloshing analysis, the sloshing frequency and wave patterns are calculated. The maximum wave height and the sloshing forces exerted on the submerged components and the primary tank are evaluated. In the fluid-structure interaction analysis, the maximum horizontal acceleration for the reactor core and the relative displacement between the reactor core and UIS are examined. The fluid-coupling phenomena between various components are investigated. Seismic stresses at critical areas are examined. The results obtained from this study are very useful to the design of the advanced reactors. Meanwhile, the computer code FLUSTR-ANL has proved to be a useful analytical tool for assessing the complicated seismic fluid-structure interactions and sloshing in the fast reactor systems. 10 refs., 25 figs

  13. Superconductivity in layered ZrP2-x Se x with PbFCl-type structure

    Ishida, Shigeyuki; Fujihisa, Hiroshi; Hase, Izumi; Yanagi, Yousuke; Kawashima, Kenji; Oka, Kunihiko; Gotoh, Yoshito; Yoshida, Yoshiyuki; Iyo, Akira; Eisaki, Hiroshi; Kito, Hijiri

    2016-05-01

    We performed a systematic study of the crystal structure, physical properties, and electronic structure of PbFCl-type ZrP2-x Se x (0.3 ≤ x ≤ 0.9). We successfully synthesized single-phase polycrystalline samples for the Se substitution range of 0.4 ≤ x ≤ 0.8. The crystal structure of the compound is characterized by the alternate stacking of a two-dimensional P square net and a Zr-(P1-x Se x ) network. ZrP2-x Se x exhibits a dome-like superconductivity phase diagram and has a maximum superconducting transition temperature (T c) of 6.3 K for x ≈ 0.6. Resistivity and Hall measurements indicated that electron-phonon scattering plays a dominant role and that electron-type carriers dominate charge transport. Specific heat measurements confirmed that ZrP2-x Se x exhibits bulk superconductivity. Further, the value of the specific heat jump at T c (ΔC/γT c ≈ 1.35) is in keeping with the BCS weak-coupling model. These facts suggest a rather conventional pairing mechanism in ZrP2-x Se x . The x dependence of T c can be explained on the basis of the density of states (DOS) for x ≤ 0.7, whereas the decrease in T c with an increase in the DOS for x = 0.8 needs further investigation. One possible reason for the suppression of superconductivity is that the PbFCl-type structure becomes unstable for x ≥ 0.8. The results of electronic structure calculations agree reasonably well with those of the experimental observations, suggesting that the Zrd band plays a primary role in determining the physical properties. Further, the calculations predict a significant change in the Fermi-surface topology for x ≥ 0.8 this is a probable reason for the decrease in T c as well as the instability of the PbFCl-type structure.

  14. Oxide-ion conduction and dielectric relaxations for fluorite type structure

    The oxide-ion conduction and dielectric properties of 10 mol% CaO stabilized ZrO2 (10CSZ) and 25 mol% Y2O3 stabilized Bi2O3 (25YSB) which are oxide ion conductors having a fluorite-type structure were investigated. The numerical analyses for the frequency dependences of dielectric constants (εr') and dielectric loss factors (εr'') revealed that the dielectric properties were explained by Debye-type polarization due to dopant-vacancy associates and/or electrolyte-electrode interfacial polarization due to charging or loss current. No Debye-type polarization was observed in 25YSB because of no effective charge at the Y3+-doped Bi3+ site. On the other hand, two Debye-type dipoles observed in 10CSZ were assigned to two kinds of associates, [CaZr''-Vo··]·, which was due to dopant-vacancy associates with two different distances between (CaZr'') and (Vo··). The frequency dependence of dielectric loss tangent (tanδ) in 25YSB was ascribed to the interface loss due to the charged current, while that of tanδ in 8YSZ was ascribed to the Debye-type dipoles in addition to the interface loss.

  15. Oxide-ion conduction and dielectric relaxations for fluorite type structure

    Yagi, Yuhji; Kawamoto, Jun-ichi; Saito, Miwa; Yamamura, Hiroshi

    2011-06-01

    The oxide-ion conduction and dielectric properties of 10 mol% CaO stabilized ZrO2 (10CSZ) and 25 mol% Y2O3 stabilized Bi2O3 (25YSB) which are oxide ion conductors having a fluorite-type structure were investigated. The numerical analyses for the frequency dependences of dielectric constants (epsilonr') and dielectric loss factors (epsilonr'') revealed that the dielectric properties were explained by Debye-type polarization due to dopant-vacancy associates and/or electrolyte-electrode interfacial polarization due to charging or loss current. No Debye-type polarization was observed in 25YSB because of no effective charge at the Y3+-doped Bi3+ site. On the other hand, two Debye-type dipoles observed in 10CSZ were assigned to two kinds of associates, [CaZr''-Vo··]·, which was due to dopant-vacancy associates with two different distances between (CaZr'') and (Vo··). The frequency dependence of dielectric loss tangent (tanδ) in 25YSB was ascribed to the interface loss due to the charged current, while that of tanδ in 8YSZ was ascribed to the Debye-type dipoles in addition to the interface loss.

  16. Data with Hierarchical Structure: Impact of Intraclass Correlation and Sample Size on Type-I Error

    Musca, Serban C.; Kamiejski, Rodolphe; Nugier, Armelle; Méot, Alain; Er-Rafiy, Abdelatif; Brauer, Markus

    2011-01-01

    Least squares analyses (e.g., ANOVAs, linear regressions) of hierarchical data leads to Type-I error rates that depart severely from the nominal Type-I error rate assumed. Thus, when least squares methods are used to analyze hierarchical data coming from designs in which some groups are assigned to the treatment condition, and others to the control condition (i.e., the widely used “groups nested under treatment” experimental design), the Type-I error rate is seriously inflated, leading too often to the incorrect rejection of the null hypothesis (i.e., the incorrect conclusion of an effect of the treatment). To highlight the severity of the problem, we present simulations showing how the Type-I error rate is affected under different conditions of intraclass correlation and sample size. For all simulations the Type-I error rate after application of the popular Kish (1965) correction is also considered, and the limitations of this correction technique discussed. We conclude with suggestions on how one should collect and analyze data bearing a hierarchical structure. PMID:21687445

  17. Structure and age-dependent development of the turkey liver: a comparative study of a highly selected meat-type and a wild-type turkey line.

    Hünigen, Hana; Mainzer, Kathleen; Hirschberg, Ruth M; Custodis, Pia; Gemeinhardt, Ole; Al Masri, Salah; Richardson, Kenneth C; Hafez, Hafez Mohamed; Plendl, Johanna

    2016-04-01

    In this study the macroscopic and microscopic structure of the liver of a fast growing, meat-type turkey line (British United turkeys BUT Big 6, n=25) and a wild-type turkey line (Wild Canadian turkey, n=48) were compared at the age of 4, 8, 12, 16, and 20 wk. Because the growth plates of long bones were still detectable in the 20-week-old wild-type turkeys, indicating immaturity, a group of 8 wild-type turkeys at the age of 24 wk was included in the original scope of the study. Over the term of the study, the body and liver weights of birds from the meat-type turkey line increased at a faster rate than those of the wild-type turkey line. However, the relative liver weight of the meat-type turkeys declined (from 2.7 to 0.9%) to a greater extent than that of the wild-type turkeys (from 2.8 to 1.9%), suggesting a mismatch in development between muscle weights and liver weights of the meat-type turkeys. Signs of high levels of fat storage in the liver were detected in both lines but were greater in the wild-type turkey line, suggesting a better feed conversion by the extreme-genotype birds i.e., meat-type birds. For the first time, this study presents morphologic data on the structure and arrangement of the lymphatic tissue within the healthy turkey liver, describing two different types of lymphatic aggregations within the liver parenchyma, i.e., aggregations with and without fibrous capsules. Despite differences during development, both adult meat-type and adult wild-type turkeys had similar numbers of lymphatic aggregations. PMID:26908884

  18. Cybernetic preductoon of AB2Ge2 composition germanides with ThCr2Si2 type crystal structure

    The prediction of AB2Ge2 composition ternary compounds with a crystalline structure of the ThCr2Si2 type has been accomplished using the training computer. The predicting table fragment containing the greatest number of forcasted phases has been given. General regularities of formation of compounds with the ThCr2Si2 type crystalline structure have been discussed

  19. Spectral structures and their generation mechanisms for solar radio type-I bursts

    The fine spectral structures of solar radio type-I bursts were observed by the solar radio telescope AMATERAS. The spectral characteristics, such as the peak flux, duration, and bandwidth, of the individual burst elements were satisfactorily detected by the highly resolved spectral data of AMATERAS with the burst detection algorithm that is improved in this study. The peak flux of the type-I bursts followed a power-law distribution with a spectral index of 2.9-3.3, whereas their duration and bandwidth were distributed more exponentially. There were almost no correlations between the peak flux, duration, and bandwidth. That means there was no similarity in the shapes of the burst spectral structures. We defined the growth rate of a burst as the ratio between its peak flux and duration. There was a strong correlation between the growth rate and peak flux. These results suggest that the free energy of type-I bursts that is originally generated by nonthermal electrons is modulated in the subsequent stages of the generation of nonthermal electrons, such as plasma wave generation, radio wave emissions, and propagation. The variation of the timescale of the growth rate is significantly larger than that of the coronal environments. These results can be explained by the situation wherein the source region may have the inhomogeneity of an ambient plasma environment, such as the boundary of open and closed field lines, and the superposition of entire emitted bursts was observed by the spectrometer.

  20. The spectra of type IIB flux compactifications at large complex structure

    Brodie, Callum; Marsh, M. C. David

    2016-01-01

    We compute the spectra of the Hessian matrix, H, and the matrix M that governs the critical point equation of the low-energy effective supergravity, as a function of the complex structure and axio-dilaton moduli space in type IIB flux compactifications at large complex structure. We find both spectra analytically in an h - 1,2 + 3 real-dimensional subspace of the moduli space, and show that they exhibit a universal structure with highly degenerate eigenvalues, independently of the choice of flux, the details of the compactification geometry, and the number of complex structure moduli. In this subspace, the spectrum of the Hessian matrix contains no tachyons, but there are also no critical points. We show numerically that the spectra of H and M remain highly peaked over a large fraction of the sampled moduli space of explicit Calabi-Yau compactifications with 2 to 5 complex structure moduli. In these models, the scale of the supersymmetric contribution to the scalar masses is strongly linearly correlated with the value of the superpotential over almost the entire moduli space, with particularly strong correlations arising for g s string theory landscape.

  1. The Spectra of Type IIB Flux Compactifications at Large Complex Structure

    Brodie, Callum

    2015-01-01

    We compute the spectra of the Hessian matrix, ${\\cal H}$, and the matrix ${\\cal M}$ that governs the critical point equation of the low-energy effective supergravity, as a function of the complex structure and axio-dilaton moduli space in type IIB flux compactifications at large complex structure. We find both spectra analytically in an $h^{1,2}_-+3$ real-dimensional subspace of the moduli space, and show that they exhibit a universal structure with highly degenerate eigenvalues, independently of the choice of flux, the details of the compactification geometry, and the number of complex structure moduli. In this subspace, the spectrum of the Hessian matrix contains no tachyons, but there are also no critical points. We show numerically that the spectra of ${\\cal H}$ and ${\\cal M}$ remain highly peaked over a large fraction of the sampled moduli space of explicit Calabi-Yau compactifications with 2 to 5 complex structure moduli. In these models, the scale of the supersymmetric contribution to the scalar masses...

  2. A Salmonella type three secretion effector/chaperone complex adopts a hexameric ring-like structure.

    Roblin, Pierre; Dewitte, Frédérique; Villeret, Vincent; Biondi, Emanuele G; Bompard, Coralie

    2015-02-15

    Many bacterial pathogens use type three secretion systems (T3SS) to inject virulence factors, named effectors, directly into the cytoplasm of target eukaryotic cells. Most of the T3SS components are conserved among plant and animal pathogens, suggesting a common mechanism of recognition and secretion of effectors. However, no common motif has yet been identified for effectors allowing T3SS recognition. In this work, we performed a biochemical and structural characterization of the Salmonella SopB/SigE chaperone/effector complex by small-angle X-ray scattering (SAXS). Our results showed that the SopB/SigE complex is assembled in dynamic homohexameric-ring-shaped structures with an internal tunnel. In this ring, the chaperone maintains a disordered N-terminal end of SopB molecules, in a good position to be reached and processed by the T3SS. This ring dimensionally fits the ring-organized molecules of the injectisome, including ATPase hexameric rings; this organization suggests that this structural feature is important for ATPase recognition by T3SS. Our work constitutes the first evidence of the oligomerization of an effector, analogous to the organization of the secretion machinery, obtained in solution. As effectors share neither sequence nor structural identity, the quaternary oligomeric structure could constitute a strategy evolved to promote the specificity and efficiency of T3SS recognition. PMID:25404693

  3. The electronic structure of zircon-type orthovanadates: Effects of high-pressure and cation substitution

    Panchal, V; Segura, A; Rodriguez-Hernandez, P; Munoz, A; Lopez-Moreno, S; Bettinelli, M; 10.1063/1.3626060

    2012-01-01

    The electronic structure of four ternary-metal oxides containing isolated vanadate ions is studied. Zircon-type YVO4, YbVO4, LuVO4, and NdVO4 are investigated by high-pressure optical-absorption measurements up to 20 GPa. First-principles calculations based on density-functional theory were also performed to analyze the electronic band structure as a function of pressure. The electronic structure near the Fermi level originates largely from molecular orbitals of the vanadate ion, but cation substitution influence these electronic states. The studied ortovanadates, with the exception of NdVO4, undergo a zircon-scheelite structural phase transition that causes a collapse of the band-gap energy. The pressure coefficient dEg/dP show positive values for the zircon phase and negative values for the scheelite phase. NdVO4 undergoes a zircon-monazite-scheelite structural sequence with two associated band-gap collapses.

  4. Flow structure of water in carbon nanotubes: poiseuille type or plug-like?

    Hanasaki, Itsuo; Nakatani, Akihiro

    2006-04-14

    We have conducted molecular dynamics simulations of water flow in carbon nanotubes (CNTs) for (6,6) to (20,20) CNTs at a streaming velocity of 100 ms. The fluidized piston model (FPM) and the ice piston model (IPM) are employed to drive flow through the CNTs. The results show that the single-file water flow inside (6,6) CNT has a convex upward streaming velocity profile, whereas the velocity profiles in (10,10) to (20,20) CNTs are flat except near the tube wall. The flow structure of cylindrical water in the (8,8) CNT is intermediate between that for the (6,6) CNT and the larger CNTs. The flow parameters are found not to exhibit any dependence on streaming velocity at up to 300 ms in the (12,12) CNT. The hydrogen bond lifetimes of water flowing in CNTs tend to be longer than for the corresponding equilibrium states, and nonzero flow does not reduce the microscopic structure or structural robustness (hydrogen bond lifetime). Although the atomic density profile varies with tube diameter, reflecting the change in static microscopic structure of flow from single file to cylindrical, tube diameter does not induce a clear transition in streaming velocity, temperature, or hydrogen bond lifetime over this diameter range. The results suggest that water flow in CNTs of this size is more pluglike than Poiseuille type, although the flow structure does not strictly accord with either definition. PMID:16626232

  5. Structural and bioinformatic characterization of an Acinetobacter baumannii type II carrier protein

    The high-resolution crystal structure of a free-standing carrier protein from Acinetobacter baumannii that belongs to a larger NRPS-containing operon, encoded by the ABBFA-003406–ABBFA-003399 genes of A. baumannii strain AB307-0294, that has been implicated in A. baumannii motility, quorum sensing and biofilm formation, is presented. Microorganisms produce a variety of natural products via secondary metabolic biosynthetic pathways. Two of these types of synthetic systems, the nonribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs), use large modular enzymes containing multiple catalytic domains in a single protein. These multidomain enzymes use an integrated carrier protein domain to transport the growing, covalently bound natural product to the neighboring catalytic domains for each step in the synthesis. Interestingly, some PKS and NRPS clusters contain free-standing domains that interact intermolecularly with other proteins. Being expressed outside the architecture of a multi-domain protein, these so-called type II proteins present challenges to understand the precise role they play. Additional structures of individual and multi-domain components of the NRPS enzymes will therefore provide a better understanding of the features that govern the domain interactions in these interesting enzyme systems. The high-resolution crystal structure of a free-standing carrier protein from Acinetobacter baumannii that belongs to a larger NRPS-containing operon, encoded by the ABBFA-003406–ABBFA-003399 genes of A. baumannii strain AB307-0294, that has been implicated in A. baumannii motility, quorum sensing and biofilm formation, is presented here. Comparison with the closest structural homologs of other carrier proteins identifies the requirements for a conserved glycine residue and additional important sequence and structural requirements within the regions that interact with partner proteins

  6. Structural and bioinformatic characterization of an Acinetobacter baumannii type II carrier protein

    Allen, C. Leigh; Gulick, Andrew M., E-mail: gulick@hwi.buffalo.edu [University at Buffalo, Buffalo, NY 14203 (United States)

    2014-06-01

    The high-resolution crystal structure of a free-standing carrier protein from Acinetobacter baumannii that belongs to a larger NRPS-containing operon, encoded by the ABBFA-003406–ABBFA-003399 genes of A. baumannii strain AB307-0294, that has been implicated in A. baumannii motility, quorum sensing and biofilm formation, is presented. Microorganisms produce a variety of natural products via secondary metabolic biosynthetic pathways. Two of these types of synthetic systems, the nonribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs), use large modular enzymes containing multiple catalytic domains in a single protein. These multidomain enzymes use an integrated carrier protein domain to transport the growing, covalently bound natural product to the neighboring catalytic domains for each step in the synthesis. Interestingly, some PKS and NRPS clusters contain free-standing domains that interact intermolecularly with other proteins. Being expressed outside the architecture of a multi-domain protein, these so-called type II proteins present challenges to understand the precise role they play. Additional structures of individual and multi-domain components of the NRPS enzymes will therefore provide a better understanding of the features that govern the domain interactions in these interesting enzyme systems. The high-resolution crystal structure of a free-standing carrier protein from Acinetobacter baumannii that belongs to a larger NRPS-containing operon, encoded by the ABBFA-003406–ABBFA-003399 genes of A. baumannii strain AB307-0294, that has been implicated in A. baumannii motility, quorum sensing and biofilm formation, is presented here. Comparison with the closest structural homologs of other carrier proteins identifies the requirements for a conserved glycine residue and additional important sequence and structural requirements within the regions that interact with partner proteins.

  7. Prediction algorithm for amino acid types with their secondary structure in proteins (PLATON) using chemical shifts

    The algorithm PLATON is able to assign sets of chemical shifts derived from a single residue to amino acid types with its secondary structure (amino acid species). A subsequent ranking procedure using optionally two different penalty functions yields predictions for possible amino acid species for the given set of chemical shifts. This was demonstrated in the case of the α-spectrin SH3 domain and applied to 9 further protein data sets taken from the BioMagRes database. A database consisting of reference chemical shift patterns (reference CSPs) was generated from assigned chemical shifts of proteins with known 3D-structure. This reference CSP database is used in our approach for extracting distributions of amino acid types with their most likely secondary structure elements (namely α-helix, β-sheet, and coil) for single amino acids by comparison with query CSPs. Results obtained for the 10 investigated proteins indicates that the percentage of correct amino acid species in the first three positions in the ranking list, ranges from 71.4% to 93.2% for the more favorable penalty function. Where only the top result of the ranking list for these 10 proteins is considered, 36.5% to 83.1% of the amino acid species are correctly predicted. The main advantage of our approach, over other methods that rely on average chemical shift values is the ability to increase database content by incorporating newly derived CSPs, and therefore to improve PLATON's performance over time

  8. Prediction algorithm for amino acid types with their secondary structure in proteins (PLATON) using chemical shifts

    Labudde, D.; Leitner, D.; Krueger, M.; Oschkinat, H. [Forschungsinstitut fuer Molekulare Pharmakologie (Germany)], E-mail: oschkinat@fmp-berlin.de

    2003-01-15

    The algorithm PLATON is able to assign sets of chemical shifts derived from a single residue to amino acid types with its secondary structure (amino acid species). A subsequent ranking procedure using optionally two different penalty functions yields predictions for possible amino acid species for the given set of chemical shifts. This was demonstrated in the case of the {alpha}-spectrin SH3 domain and applied to 9 further protein data sets taken from the BioMagRes database. A database consisting of reference chemical shift patterns (reference CSPs) was generated from assigned chemical shifts of proteins with known 3D-structure. This reference CSP database is used in our approach for extracting distributions of amino acid types with their most likely secondary structure elements (namely {alpha}-helix, {beta}-sheet, and coil) for single amino acids by comparison with query CSPs. Results obtained for the 10 investigated proteins indicates that the percentage of correct amino acid species in the first three positions in the ranking list, ranges from 71.4% to 93.2% for the more favorable penalty function. Where only the top result of the ranking list for these 10 proteins is considered, 36.5% to 83.1% of the amino acid species are correctly predicted. The main advantage of our approach, over other methods that rely on average chemical shift values is the ability to increase database content by incorporating newly derived CSPs, and therefore to improve PLATON's performance over time.

  9. Crystal structure of a novel cysteinless plant Kunitz-type protease inhibitor

    Bauhinia bauhinioides Cruzipain Inhibitor (BbCI) is a cysteine protease inhibitor highly homologous to plant Kunitz-type inhibitors. However, in contrast to classical Kunitz family inhibitors it lacks cysteine residues and therefore disulfide bridges. BbCI is also distinct in the ability to inactivate enzymes belonging to two different classes, cysteine and serine proteases. Besides inhibiting the cysteine protease cruzipain, BbCI also inhibits cathepsin L and the serine proteases HNE (human neutrophil elastase) and PPE (porcine pancreatic elastase). Monoclinic crystals of the recombinant inhibitor that diffract to 1.7 A resolution were obtained using hanging drop method by vapor diffusion at 18 oC. The refined structure shows the conservative β-trefoil fold features of the Kunitz inhibitors. In BbCI, one of the two characteristic S-S bonds is replaced by the water-mediated interaction between Tyr125 and Gly132. In this work we explore the structural differences between Kunitz-type inhibitors and analyze the essential interactions that maintain the protein structural stability preserving its biological function

  10. Structural analysis on the open basket type instrumented capsule for fuel irradiation test in HANARO

    To develop the open basket type instrumented capsule to be used for the irradiation test of various nuclear fuels, it is necessary to ensure the compatibility of a capsule with HANARO and the structural integrity of a capsule. The dimensions of open basket type instrumented capsule was determined in the basis of the pressure drop criterion in OR test hole of HANARO(mass flow rate m200kPa). From the buckling stability analysis for this capsule, the critical buckling load Pcr was 7.5kN. The vertical impact stress of the capsule under unit impact load was examined by the transient analysis, and the maximum vertical impact load calculated from the impact stress and the allowable stress was 65.3kN. And under the loading Pcr calculated from the analysis of buckling of capsule, the maximum vertical impact stress was 20.4MPa. The structural integrity of a capsule under horizontal impact loading was also examined. The mechanical stresses occurred by a pressure difference at the inner and outer surface of cladding and by a coolant pressure at the surface of cladding were 2.32MPa and 40.55MPa, respectively. Theses stress values were lower than the allowable stress in each case. Therefore, it was ensured that the instrumented capsule for the irradiation test of various nuclear fuels meets the criteria on the structural integrity during installing, and testing the capsule in HANARO

  11. Fluid Flow through Porous Sandstone with Overprinting and Intersecting Geological Structures of Various Types

    Zhou, X.; Karimi-Fard, M.; Durlofsky, L.; Aydin, A.

    2010-12-01

    Impact of a wide variety of structural heterogeneities on fluid flow in an aeolian sandstone in the Valley of Fire State Park (NV), such as (1) dilatant fractures (joints), (2) shear fractures (faults), and (3) contraction/compaction structures (compaction bands), are considered. Each type of these structures has its own geometry, spacing, distribution, connectivity, and hydraulic properties, which either enhance or impede subsurface fluid flow. Permeability of these structures may, on average, be a few orders of magnitude higher or lower than those of the corresponding matrix rocks. In recent years, the influence of a single type of these heterogeneities on fluid flow has been studied individually, such as joints, compaction bands or faults. However, as different types of geological structures are commonly present together in the same rock volume, their combined effect requires a more detailed assessment. In this study, fluid flow simulations are performed using a special finite-volume discretization technique that was developed by Karimi-Fard et al. (2004; 2006). Using this approach, thin features such as fractures and compaction bands are represented as linear elements in unstructured 2D models and as planar elements in 3D models, which significantly reduces the total number of cells and simplifies grid generation. The cell geometric information and the cell-to-cell transmissibility obtained from this discretization technique are input to Stanfords General Purpose Research Simulator (GPRS) for fluid flow simulation. To account for the effects of the various geological structures on subsurface flow, we perform permeability upscaling over regions corresponding to large-scale simulation grid blocks in order to obtain equivalent permeability components in two principal directions. We will focus on the following problems: (1) compaction bands of multisets; (2) compartmentalization of compaction bands of high-angle, low-angle and horizontal; (3) joints overprinting and intersecting earlier compaction and shear bands at various angles; (4) faults with various sizes overprinting and intersecting earlier compaction and shear bands. The preliminary results are: (1) Sets of compaction bands in various orientations are capable of compartmentalizing the rock volume. (2) If one set of joints are parallel to one set of compaction bands, the combined effect to the upscaled permeability is not significant. (3) If a joint set intersects a set of compaction bands, the combined effect counter acts the impeding of fluid flow by the compaction bands at high-angle to the bands. On the other hand the effect on the upscaled permeability in the direction of the bands is not significant. The effects of the combination of faults and compaction bands on fluid flow in various directions are complex and being evaluated.

  12. Structural Biology Insight for the Design of Sub-type Selective Aurora Kinase Inhibitors.

    Sarvagalla, Sailu; Coumar, Mohane Selvaraj

    2015-01-01

    Aurora kinase A, B and C, are key regulators of mitosis and are over expressed in many of the human cancers, making them an ideal drug target for cancer chemotherapy. Currently, over a dozen of Aurora kinase inhibitors are in various phases of clinical development. The majority of the inhibitors (VX-680/MK-0457, PHA-739358, CYC116, SNS-314, AMG 900, AT-9283, SCH- 1473759, ABT-348, PF-03814735, R-763/AS-703569, KW-2449 and TAK-901) are pan-selective (isoform non-selective) and few are Aurora A (MLN8054, MLN8237, VX-689/MK5108 and ENMD 2076) and Aurora B (AZD1152 and GSK1070916) sub-type selective. Despite the intensive research efforts in the past decade, no Aurora kinase inhibitor has reached the market. Recent evidence suggests that the sub-type selective Aurora kinase A inhibitor could possess advantages over pan-selective Aurora inhibitors, by avoiding Aurora B mediated neutropenia. However, sub-type selective Aurora kinase A inhibitor design is very challenging due to the similarity in the active site among the isoforms. Structural biology and computational aspects pertaining to the design of Aurora kinase inhibitors were analyzed and found that a possible means to develop sub-type selective inhibitor is by targeting Aurora A specific residues (Leu215, Thr217 and Arg220) or Aurora B specific residues (Arg159, Glu161 and Lys164), near the solvent exposed region of the protein. Particularly, a useful strategy for the design of sub-type selective Aurora A inhibitor could be by targeting Thr217 residue as in the case of MLN8054. Further preclinical and clinical studies with the sub-type selective Aurora inhibitors could help bring them to the market for the treatment of cancer. PMID:25895501

  13. Assembly of Na3V2(PO4)3 nanoparticles confined in a one-dimensional carbon sheath for enhanced sodium-ion cathode properties.

    Kajiyama, Satoshi; Kikkawa, Jun; Hoshino, Junichi; Okubo, Masashi; Hosono, Eiji

    2014-09-22

    Structural and morphological control is an effective approach for improvement of electrochemical properties in rechargeable batteries. One-dimensionally assembled structure composed of NASICON-type Na3 V2 (PO4 )3 nanoparticles were fabricated through an electrospinning method to meet the requirements for the development of efficient electrode materials in Na-ion batteries. High-temperature treatment of electrospun precursor fibers under an argon flow provides a nonwoven fabric of nanowires comprising crystallographically oriented nanoparticles of NASICON-type Na3 V2 (PO4 )3 within a carbon sheath. The mesostructure comprising NASICON-type Na3 V2 (PO4 )3 and carbon give a short sodium-ion transport pass and an efficient electron conduction pass. Electrochemical properties of NASICON-type Na3 V2 (PO4 )3 are improved on the basis of one-dimensional nanostructures designed in the present study. PMID:25123497

  14. Mechanical adaptability of the Bouligand-type structure in natural dermal armour

    Zimmermann, Elizabeth A.; Gludovatz, Bernd; Schaible, Eric; Dave, Neil K. N.; Yang, Wen; Meyers, Marc A.; Ritchie, Robert O.

    2013-10-01

    Arapaima gigas, a fresh water fish found in the Amazon Basin, resist predation by piranhas through the strength and toughness of their scales, which act as natural dermal armour. Arapaima scales consist of a hard, mineralized outer shell surrounding a more ductile core. This core region is composed of aligned mineralized collagen fibrils arranged in distinct lamellae. Here we show how the Bouligand-type (twisted plywood) arrangement of collagen fibril lamellae has a key role in developing their unique protective properties, by using in situ synchrotron small-angle X-ray scattering during mechanical tensile tests to observe deformation mechanisms in the fibrils. Specifically, the Bouligand-type structure allows the lamellae to reorient in response to the loading environment; remarkably, most lamellae reorient towards the tensile axis and deform in tension through stretching/sliding mechanisms, whereas other lamellae sympathetically rotate away from the tensile axis and compress, thereby enhancing the scales ductility and toughness to prevent fracture.

  15. The structure of a lipid-water lamellar phase containing two types of lipid monolayers

    One lamellar phase, observed in the mitochondrial lipids-water system at low temperature (ca 253 K) and at low water content (ca 15%), contains four lipid monolayers in its unit cell, two of type α and two of type β. Previous X-ray scattering studies of this phase led to an ambiguity: the phase could contain either two homogeneous bilayers, one α and one β, or two mixed bilayers, each formed by an α and a β monolayer. A solution to this problem was sought in a neutron scattering study as a function of the D2O/H2O ratio. Because of limited resolution, straightforward analysis of the neutron scattering data leads also to ambiguous results. Using a more sophisticated analysis based upon the zeroth- and second-order moments of the Patterson peaks relevant to the exchangeable components, it is shown that the weight of the evidence is in favour of a structure containing mixed bilayers. (Auth.)

  16. Structural Characterization of Lignin in Wild-type versus COMT Down-regulated Switchgrass

    ArthurRagauskas

    2014-01-01

    Full Text Available This study examined the chemical structural characteristics of cellulolytic enzyme lignin isolated from switchgrass focusing on comparisons between wild-type control and caffeic acid 3-O-methyltransferase (COMT down-regulated transgenic line. Nuclear magnetic resonance (NMR techniques including 13C, 31P, and two-dimensional 13C-1H heteronuclear single quantum coherence (HSQC as well as gel permeation chromatography (GPC were employed. Compared to the wild-type, the COMT down-regulated transgenic switchgrass lignin demonstrated a decrease in syringyl (S: guaiacyl (G ratio and p-coumarate:ferulate ratio, an increase in relative abundance of phenylcoumaran unit, and a comparable content of total free phenolic OH groups along with formation of benzodioxane unit. In addition, COMT down-regulation had no significant effects on the lignin molecular weights during its biosynthesis process.

  17. Direct metal micropatterning on needle-type structures towards bioimpedance and chemical sensing applications

    Kim, Sanghyeok; Park, Jae-ho; Kang, Kyungnam; Park, Chong-Ook; Park, Inkyu

    2015-01-01

    Direct metal patterning methods, such as screen printing, inkjet printing and gravure/flexography printing, are widely used to form electrodes or interconnections for printed electronic devices due to their inexpensive, simple and rapid fabrication as compared to vacuum-based conventional metallization processes. Here, we present direct metal patterning by modified screen printing on the curved surface of needle-type rod structures (i.e. rods with radius of ? electrochemical impedance spectroscopy of electrolyte solutions and solid objects by the rod insertion. Furthermore, needles with multiple pairs of microelectrodes were used to measure the electrical impedance of biological samples such as fat and muscle tissues of porcine meat. In addition, a needle-type probe sensor with gas sensing capability was demonstrated by using a needle with printed Ag electrodes and Pd thin films.

  18. Function and Evolutionary Origin of Unicellular Camera-Type Eye Structure

    Hayakawa, Shiho

    2015-03-03

    The ocelloid is an extraordinary eyespot organelle found only in the dinoflagellate family Warnowiaceae. It contains retina- and lens-like structures called the retinal body and the hyalosome. The ocelloid has been an evolutionary enigma because of its remarkable resemblance to the multicellular camera-type eye. To determine if the ocelloid is functionally photoreceptive, we investigated the warnowiid dinoflagellate Erythropsidinium. Here, we show that the morphology of the retinal body changed depending on different illumination conditions and the hyalosome manifests the refractile nature. Identifying a rhodopsin gene fragment in Erythropsidinium ESTs that is expressed in the retinal body by in situ hybridization, we also show that ocelloids are actually light sensitive photoreceptors. The rhodopsin gene identified is most closely related to bacterial rhodopsins. Taken together, we suggest that the ocelloid is an intracellular camera-type eye, which might be originated from endosymbiotic origin. © 2015 Hayakawa et al.

  19. Structural and magnetic Properties of TbZn-substituted calcium barium M-type nano-structured hexa-ferrites

    Khan, Hasan M. [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Department of Electronics, University of York, York YO10 5DD (United Kingdom); Islam, M.U., E-mail: dr.misbahulislam@bzu.edu.pk [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Xu, Yongbing [Department of Electronics, University of York, York YO10 5DD (United Kingdom); NanjingYork International Centre of Spintronics and Nano-Engineering, Nanjing University, Nanjing 210093 (China); Asif Iqbal, M. [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); National University of Science and Technology, College of E and ME, Islamabad (Pakistan); Ali, Irshad [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan)

    2014-03-15

    Highlights: TbZn substituted Ca{sub 0.5}Ba{sub 0.5}Fe{sub 12}O{sub 19} samples exhibit single magnetoplumbite phase. Lattice parameters a and c have increasing values. Coercivity can be tuned at lower substitution level Crystallites size was found in the range 1825 nm by TEM and by Scherrer formula. These hexa-ferrites are suitable for microwave devices and magnetic recording media. -- Abstract: Effect of TbZn substitution on the structural and magnetic properties of Ca{sub 0.5}Ba{sub 0.5?x}Tb{sub x}Zn{sub y}Fe{sub 12?y}O{sub 19}, (x = 0.000.10; y = 0.001.00) ferrites prepared by solgel auto combustion is reported. The synthesized samples were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Vibrating Sample magnetometery. The X-ray diffraction analysis confirmed single phase M-type hexa-ferrite structure. The lattice parameters were found to increase as TbZn contents increases, which is attributed to the ionic sizes of the implicated cations. The TbZn seems to be completely soluble in the lattice. The results of scanning electron microscopy and transmission electron microscopy shows that the grain size decreases with increase of TbZn substitution. The coercivity values (12772025 Oe) of all samples lies in the range of M-type hexa-ferrite and indicate that an increase of anisotropy was achieved by substitution of TbZn, while the size of nanoparticles was drastically reduced between 18 and 25 nm. The increased anisotropy and fine particle size are useful for many applications, such as improving signal noise ratio of recording devices.

  20. Comparative study on the effects of type 1 and type 2 diabetes on structural changes and hormonal output of the adrenal cortex in male Wistar rats

    Elahi-Moghaddam Zohreh

    2013-01-01

    Full Text Available Abstract Introduction Diabetes is one of the most common endocrine disorders characterized by hyperglycemia due to defects in insulin secretion, insulin function, or both. Causing dysfunction in the body general metabolism, diabetes-induced chronic hyperglycemia leads to alterations in those endocrine glands involved in regulating the body metabolism. In this line, the present study has been conducted to investigate the effects of type 1 and type 2 diabetes on the structural changes and hormonal output of the adrenal cortex in male Wistar rat. Methods Eighteen male Wistar rats were divided into three groups including control, experimental type 1 diabetes (subcutaneous injection of 135 mg/kg alloxan and experimental type 2 diabetes (8 weeks treatment with drinking water containing 10% fructose. Two months after the induction of both types of diabetes, the level of blood biochemical factors (glucose, insulin, cortisol, triglycerides, cholesterol, LDL, and HDL were measured. Structural changes of the adrenal cortex were then evaluated, using stereological techniques. Results Serum biochemical analysis showed significant difference in the levels of glucose, triglycerides, insulin and cortisol in experimental groups, compared to the control. The results of structural alterations were also indicative of increase in adrenal cortex volume in both types of diabetes. Conclusion Probably through increasing HPA axis activity, type1 diabetes-induced hyperglycemia leads to adrenal hypertrophy and increase the hormonal output of adrenal gland.

  1. Structural Basis for Type VI Secretion Effector Recognition by a Cognate Immunity Protein

    Li, Mo; Le Trong, Isolde; Carl, Mike A.; Larson, Eric T.; Chou, Seemay; De Leon, Justin A.; Dove, Simon L.; Stenkamp, Ronald E.; Mougous, Joseph D.

    2012-01-01

    The type VI secretion system (T6SS) has emerged as an important mediator of interbacterial interactions. A T6SS from Pseudomonas aeruginosa targets at least three effector proteins, type VI secretion exported 13 (Tse13), to recipient Gram-negative cells. The Tse2 protein is a cytoplasmic effector that acts as a potent inhibitor of target cell proliferation, thus providing a pronounced fitness advantage for P. aeruginosa donor cells. P. aeruginosa utilizes a dedicated immunity protein, type VI secretion immunity 2 (Tsi2), to protect against endogenous and intercellularly-transferred Tse2. Here we show that Tse2 delivered by the T6SS efficiently induces quiescence, not death, within recipient cells. We demonstrate that despite direct interaction of Tsi2 and Tse2 in the cytoplasm, Tsi2 is dispensable for targeting the toxin to the secretory apparatus. To gain insights into the molecular basis of Tse2 immunity, we solved the 1.00 X-ray crystal structure of Tsi2. The structure shows that Tsi2 assembles as a dimer that does not resemble previously characterized immunity or antitoxin proteins. A genetic screen for Tsi2 mutants deficient in Tse2 interaction revealed an acidic patch distal to the Tsi2 homodimer interface that mediates toxin interaction and immunity. Consistent with this finding, we observed that destabilization of the Tsi2 dimer does not impact Tse2 interaction. The molecular insights into Tsi2 structure and function garnered from this study shed light on the mechanisms of T6 effector secretion, and indicate that the Tse2Tsi2 effectorimmunity pair has features distinguishing it from previously characterized toxinimmunity and toxinantitoxin systems. PMID:22511866

  2. Dipole ordering, ionic conductivity, and cold nuclear fusion: Three types of cation mobility in the orthophosphates KTiOPO4 Na3M2(PO4)3 (M=Sc,Fe,Cr), NaTh2(PO4)3, KD2PO4, and related compounds

    As shown in earlier studies, crystals whose structures contain closely located positions statistically occupied by metal cations (split positions) may exhibit anomalies in physical properties, such as ferroelectric (FE) or antiferroelectric (AFE) ordering, superionic conduction (SIC), low thermal expansion coefficients, ultrarapid nuclear relaxation, etc. For example, splitting of Na positions lead to Fe ordering in low-temperature structures of Na3Sc2(PO4)3 and NaTh2(PO4)3 and to AFE ordering in Na3Zr2Si2PO12 (stoichiometric NASICON - one of the best three-dimensional superionic conductors). The coexistance of two types of split cation positions in KFeFPO4 was reported by Belokoeneva et al.; later, these splittings were shown to be accompanied by FE and AFE ordering. In this paper, the authors report an attempt to establish inter-relations between various physical phenomena related to cation mobility. They discuss three manifestations of cation mobility in orthophosphates with split cation positions: dipole ordering of both FE and AFE types, superionic conduction, and cold nuclear fusion (CNF)

  3. Impact of model structure and parameterization on Penman-Monteith type evaporation models

    Ershadi, A.

    2015-04-12

    The impact of model structure and parameterization on the estimation of evaporation is investigated across a range of Penman-Monteith type models. To examine the role of model structure on flux retrievals, three different retrieval schemes are compared. The schemes include a traditional single-source Penman-Monteith model (Monteith, 1965), a two-layer model based on Shuttleworth and Wallace (1985) and a three-source model based on Mu et al. (2011). To assess the impact of parameterization choice on model performance, a number of commonly used formulations for aerodynamic and surface resistances were substituted into the different formulations. Model response to these changes was evaluated against data from twenty globally distributed FLUXNET towers, representing a cross-section of biomes that include grassland, cropland, shrubland, evergreen needleleaf forest and deciduous broadleaf forest. Scenarios based on 14 different combinations of model structure and parameterization were ranked based on their mean value of Nash-Sutcliffe Efficiency. Results illustrated considerable variability in model performance both within and between biome types. Indeed, no single model consistently outperformed any other when considered across all biomes. For instance, in grassland and shrubland sites, the single-source Penman-Monteith model performed the best. In croplands it was the three-source Mu model, while for evergreen needleleaf and deciduous broadleaf forests, the Shuttleworth-Wallace model rated highest. Interestingly, these top ranked scenarios all shared the simple lookup-table based surface resistance parameterization of Mu et al. (2011), while a more complex Jarvis multiplicative method for surface resistance produced lower ranked simulations. The highly ranked scenarios mostly employed a version of the Thom (1975) formulation for aerodynamic resistance that incorporated dynamic values of roughness parameters. This was true for all cases except over deciduous broadleaf sites, where the simpler aerodynamic resistance approach of Mu et al. (2011) showed improved performance. Overall, the results illustrate the sensitivity of Penman-Monteith type models to model structure, parameterization choice and biome type. A particular challenge in flux estimation relates to developing robust and broadly applicable model formulations. With many choices available for use, providing guidance on the most appropriate scheme to employ is required to advance approaches for routine global scale flux estimates, undertake hydrometeorological assessments or develop hydrological forecasting tools, amongst many other applications. In such cases, a multi-model ensemble or biome-specific tiled evaporation product may be an appropriate solution, given the inherent variability in model and parameterization choice that is observed within single product estimates.

  4. Thermal expansion behaviour of sodium zirconium phosphate structure type phosphates containing tin

    Thermal expansion behaviour of sodium zirconium phosphate structure type phosphates of the formula AM3+SnP3O12 (A=Ca, Sr and Ba; M3+=Cr and Fe) was studied by high temperature X-ray diffraction and dilatometry in the temperature range 298-1073 K. The variation in the hexagonal lattice parameters of the Ca-containing compounds is in line with the 'sodium zirconium phosphate behaviour'. However, the strontium- and barium-containing compounds display an altogether different behaviour of axial expansion. The results are explained based on the crystal chemistry of these compounds

  5. Structure-Activity Relationship of a U-Type Antimicrobial Microemulsion System

    ZHANG Hui; Taxipalati, Maierhaba; Yu, Liyi; Que, Fei; Feng, Fengqin

    2013-01-01

    The structure-activity relationship of a U-type antimicrobial microemulsion system containing glycerol monolaurate and ethanol at a 1∶1 mass ratio as oil phase and Tween 20 as surfactant were investigated along a water dilution line at a ratio of 80∶20 mass% surfactant/oil phase, based on a pseudo-ternary phase diagram. The differential scanning calorimetry results showed that in the region of up to 33% water, all water molecules are confined to the hydrophilic core of the reverse micelles, l...

  6. Ternary borides with CeNi12B6 type structure

    The well-known LnNi12B6 and ∼ LnNi12B7 (Ln-Y, La, Pr, Nd, Sm, Gd) and prepared for the first time LnNi12B6(Ln-Tb, Dy) borides are proved to possess the rhombic structure of CeNi12B6 type. The parameters of the elementary cells for all compounds are determined. Continuous change in the parameters points to the three-valent state of rare earth atoms

  7. Hilbert space structures on the solution space of Klein-Gordon-type evolution equations

    We use the theory of pseudo-Hermitian operators to address the problem of the construction and classification of positive-definite invariant inner-products on the space of solutions of a Klein-Gordon-type evolution equation. This involves dealing with the peculiarities of formulating a unitary quantum dynamics in a Hilbert space with a time-dependent inner product. We apply our general results to obtain possible Hilbert space structures on the solution space of the equation of motion for a classical simple harmonic oscillator, a free Klein-Gordon equation and the Wheeler-DeWitt equation for the FRW-massive-real-scalar-field models

  8. A note on the prolongation structure of the cubically nonlinear integrable Camassa-Holm type equation

    In this Letter, we formulate an exterior differential system for the newly discovered cubically nonlinear integrable Camassa-Holm type equation. From the exterior differential system we establish the integrability of this equation. We then study Cartan prolongation structure of this equation. We also discuss the method of identifying conservation laws and Baecklund transformation for this equation from the identified exterior differential system. -- Highlights: → An exterior differential system for a cubic nonlinear integrable equation is given. → The conservation laws from the exterior differential system is derived. → The Baecklund transformation from the Cartan-Ehresmann connection is obtained.

  9. Cation states of iron in complicated oxides with various derivative type of structure from perovskite

    Full text:The following oxides have been investigated: ortho ferrites (OF) LnFe2/3Mo1/3O3 (Ln = La, Ce, Pr, Nd), and oxygen-deficient perovskites with various structure types Pr4BaCu4FeOl3-δ (δ = 0, 0.5, type 4-1-5), Ln8-ySryCu8-xFexO20 (Ln = La, Nd, Pr, y=1.6-4, x = 1.6-3, type 8-8-20) and YBa2yLayCu3-xFexO7-δ, Y1yCayBa2-yLayCu3-xFexO7-δ (y = 0.25, 0.5, x = 0.06, 0.12, δ≅ 0.05, type 1-2-3). All investigated compounds are given by Institute of Chemistry of Ural branch of RAS (Ekaterinburg, G.V. Bazuev's laboratory). The Moessbauer spectroscopy on an isotope 57Fe was the basic method of researches. At some stages of researches as an additional method also X-ray analysis has been used. All considered types of perovskite-related structures are characterized by the general attribute of relationship - presence of layers, packages or skeletons from connected by tops octahedrons MeO6 (in our case Me = Cu, Fe, Mo) or their rests as pyramids MeO5, squares MeO4 and dumbbells MeO2 in oxygen-deficient compounds. The selection of samples (sequence of their research) was made so, that each subsequent structure row has the bigger 'deficiency' of oxygen in recalculation on an elementary cell of ideal perovskite (formula unit ABX3, where A, B -cations, X - anion): 1) ABX3 (OF); 2) A5B5X15-2=5xABX2.6 (4-1-5); 3) A8B8X24-4 = 8xABX2.5 (8-8-20); 4) A3B3X9-2 = 3xABX2.3 (1-2-3). The carried out studies show: 1) magnetic ordering of iron cations (at room temperature) in all researched oxides with the structures derivative from perovskite arises only in octahedral positions; It can be explained by the fact, that the increase in oxygen deficiency results in break of chains Fe-O-Fe through which there is an exchange interaction; 2) in OF and 4-1-5 oxides iron is only as Fe3+ in oxygen-deficient compounds of type 8-8-20 and 1-2-3 - in mixed valent state Fe3+ -Fe4+; i.e. to growth of deficiency of structural anions there is a displacement of a valent state of iron ions from '+3' to '+4'; 3) in OF Fe- and Mo- cations are statistically distributed on octahedral sites of structure; in compounds of type 4-1-5 and 8-8-20, iron placed in octahedral and pyramidal positions both independently of iron concentration; in oxides of type 1-2-3 iron substitutes copper only in positions Cu, having various oxygen coordination: from a square plane up to an octahedron; the majority iron atoms in perovskite-related structures are placed in octahedral positions, further on 'population' square pyramids and squares plane follow; it is explained following: at first place the iron ions prefer octahedral coordination, at second - in case of oxygen-deficient structures first two coordinations are resulted not only by substitution of copper in these positions, but also by attraction of additional oxygen in the environment; 4) the increase of oxygen deficiency results in downturn of symmetry of structural polyhedrons: the most symmetric polyhedrons in OF, further follow compounds of type 4-1-5, 8-8-20 and 1-2-3. The present work has been performed with the support of the grants of Tatarstan Academy of Sciences No. 06-6.1-142, CRDF (REC-007), Scientific School-1708.2003.2

  10. Long-wavelength infrared detection in a Kastalsky-type superlattice structure

    Byungsung, O.; Choe, J.-W.; Francombe, M. H.; Bandara, K. M. S. V.; Coon, D. D.

    1990-01-01

    The first successful demonstration of long-wavelength infrared (LWIR) detection with a Kastalsky-type AlGaAs/GaAs superlattice structure is reported. The experimental response band of the detector is centered near 10 microns in very good agreement with the theoretical response band provided that electron-electron interactions are taken into account. The detector operates at significantly lower bias voltage than photoconductive multiple quantum well LWIR detectors. This could lead to important advantages in applications to photovoltaic detector arrays. The response at 83 K is about 50 percent of the response at 24 K.

  11. Electronic structure of ionic PbFCl-type compounds under pressure

    Kanchana, V; Rajagopalan, M

    2003-01-01

    The electronic structures of alkaline-earth fluoro-halides - SrFBr, SrFI, and CaFBr, which crystallize in the PbFCl-type structure - have been studied using the tight-binding linear muffin-tin orbital method within the local density approximation. The total energies were calculated using the atomic sphere approximation and were used to determine the ground state properties of these systems. The calculated ground state properties agree fairly well with the experimental results. These systems were found to be direct band gap insulators. The pressure dependence of the band gap was also studied. The band gap closes at high pressures leading to band overlap. A possible reason for the metallization in these compounds is discussed.

  12. On the Structural Types of Reduplicative in The Book of Songs

    Binghua DONG

    2011-12-01

    Full Text Available

    The Book of Songs is a collection of poems and songs in Chinese Qin Dynasty, in which featured by a lot of using of reduplicative. This paper, based on the results of previous scholars, analyzes the structural types of reduplicative inThe Book of Songsfrom the aspects of reduplicative in radical, in rhymes and both. This paper is aimed to better understand the meaning of The Book of Songs, so as to improve language teaching and practical using, as well as help with corpus and theories.

    Key words: The Book of Songs; Reduplicative; Structure; Reduplicative in radical; Reduplicative in rhymes

  13. Heterotic and type II orientifold compactifications on SU(3) structure manifolds

    We study the four-dimensional N=1 effective theories of generic SU(3) structure compactifications in the presence of background fluxes. For heterotic and type IIA/B orientifold theories, the N=1 characteristic data are determined by a Kaluza-Klein reduction of the fermionic actions. The Kaehler potentials, superpotentials and the D-terms are entirely encoded by geometrical data of the internal manifold. The background flux and the intrinsic torsion of the SU(3) structure manifold, gives rise to contributions to the four-dimensional F-terms. The corresponding superpotentials generalize the Gukov-Vafa-Witten superpotential. For the heterotic compactification, the four-dimensional fermionic supersymmetry variations, as well as the conditions on supersymmetric vacua, are determined. The Yukawa couplings of the theory turn out to be similar to their Calabi-Yau counterparts. (Orig.)

  14. Paired structures, imprecision types and two-level knowledge representation by means of opposites

    Rodríguez, J. Tinguaro; Franco de los Ríos, Camilo; Gómez, Daniel; Montero, Javier

    Opposition-based models are a current hot-topic in knowledge representation. The point of this paper is to suggest that opposition can be in fact introduced at two different levels, those of the predicates of interest being represented (as short/tall) and of the logical references (true/false) used...... to evaluate the verification of the former. We study this issue by means of the consideration of different paired structures at each level. We also pay attention at how different types of fuzziness may be introduced in these paired structures to model imprecision and lack of knowledge. As a...... consequence, we obtain a unifying framework for studying the relationships between different knowledge representation models and different kinds of uncertainty....

  15. Creep deformation and rupture behavior of type 304/308 stainless steel structural weldments

    The creep deformation and rupture of type 304/308 stainless steel structural weldments at 5930C (11000F) was experimentally investigated to study the comparative behavior of the base metal and weld metal constituents. The tests were conducted in support of ORNL's program to develop high-temperature structural design methods applicable to liquid-metal fast breeder reactor (LMFBR) system components that operate in the creep range. The specimens used were thin-walled, right circular cylinders capped with either flat or hemispherical heads and tested under internal gas pressure. Circumferential welds were located in different regions of the cylinder or head and, with one exception, were geometrically duplicated by all base metal regions in companion specimens. Results are presented on the comparative deformation and rupture behavior of selected points in the base metal and weldment regions of the different specimens and on the overall surface strains for selected specimens

  16. DG-FEM solution for nonlinear wave-structure interaction using Boussinesq-type equations

    Engsig-Karup, Allan Peter; Hesthaven, Jan; Bingham, Harry B.; Warburton, T.

    2008-01-01

    We present a high-order nodal Discontinuous Galerkin Finite Element Method (DG-FEM) solution based on a set of highly accurate Boussinesq-type equations for solving general water-wave problems in complex geometries. A nodal DG-FEM is used for the spatial discretization to solve the Boussinesq...... equations in complex and curvilinear geometries which amends the application range of previous numerical models that have been based on structured Cartesian grids. The Boussinesq method provides the basis for the accurate description of fully nonlinear and dispersive water waves in both shallow and deep...... waters within the breaking limit. To demonstrate the current applicability of the model both linear and mildly nonlinear test cases are considered in two horizontal dimensions where the water waves interact with bottom-mounted fully reflecting structures. It is established that, by simple symmetry...

  17. Relationships between NDVI, canopy structure, and photosynthesis in three California vegetation types

    In a range of plant species from three Californian vegetation types, we examined the widely used ''normalized difference vegetation index'' (NDVI) and ''simple ratio'' (SR) as indicators of canopy structure, light absorption, and photosynthetic activity. These indices, which are derived from canopy reflectance in the red and near-infrared wavebands, highlighted phenological differences between evergreen and deciduous canopies. They were poor indicators of total canopy biomass due to the varying abundance of non-green standing biomass in these vegetation types. However, in sparse canopies (leaf area index (LAI) apprxeq 0-2), NDVI was a sensitive indicator of canopy structure and chemical content (green biomass, green leaf area index, chlorophyll content, and foliar nitrogen content). At higher canopy green LAI values ( gt 2; typical of dense shrubs and trees), NDVI was relatively insensitive to changes in canopy structure. Compared to SR, NDVI was better correlated with indicators of canopy structure and chemical content, but was equivalent to the logarithm of SR. In agreement with theoretical expectations, both NDVI and SR exhibited near-linear correlations with fractional PAR intercepted by green leaves over a wide range of canopy densities. Maximum daily photosynthetic rates were positively correlated with NDVI and SR in annual grassland and semideciduous shrubs where canopy development and photosynthetic activity were in synchrony. The indices were also correlated with peak springtime canopy photosynthetic rates in evergreens. However, over most of the year, these indices were poor predictors of photosynthetic performance in evergreen species due to seasonal reductions in photosynthetic radiation-use efficiency that occurred without substantial declines in canopy greenness. Our results support the use of these vegetation indices as remote indicators of PAR absorption, and thus potential photosynthetic activity, even in heterogeneous landscapes. To provide accurate estimates of vegetation atmosphere gas fluxes, remote NDVI and SR measurements need to be coupled with careful estimates of canopy photosynthetic radiation-use efficiency. (author)

  18. Changes in electronic structure upon lithium insertion into Fe2(SO4)3 and Fe2(MoO4)3 investigated by X-ray absorption spectroscopy.

    Shirakawa, Junichi; Nakayama, Masanobu; Wakihara, Masataka; Uchimoto, Yoshiharu

    2007-02-15

    Changes in electronic structure upon electrochemical lithium insertion into two iron compounds, namely, rhombohedral Fe2(SO4)3 with a NASICON-type structure and monoclinic Fe2(MoO4)3, were investigated using X-ray absorption spectroscopy (XAS). Fe K-edge and L(III)- and L(II)-edge XAS revealed that the rearrangement of Fe d electrons or rehybridization of Fe d-O p bonding took place accompanied by the reduction of Fe ions upon Li insertion for both samples and that a larger change in spectra was observed in Fe2(SO4)3. In addition, the changes in the electronic structure of the polyanion units XO4(2-) (X = S or Mo) after Li insertion were also investigated by O K-edge and S K-edge or Mo L(III)-edge XAS. The results indicated that the electronic structure around oxygen markedly changed in Fe2(MoO4)3, while no significant change was observed in Fe2(SO4)3. PMID:17249717

  19. Pentameric quaternary structure of the intracellular domain of serotonin type 3A receptors.

    Pandhare, Akash; Grozdanov, Petar N; Jansen, Michaela

    2016-01-01

    In spite of extensive efforts over decades an experimentally-derived structure of full-length eukaryotic pentameric ligand-gated ion channels (pLGICs) is still lacking. These pharmaceutically highly-relevant channels contain structurally well-conserved and characterized extracellular and transmembrane domains. The intracellular domain (ICD), however, has been orphaned in structural studies based on the consensus assumption of being largely disordered. In the present study, we demonstrate for the first time that the serotonin type 3A (5-HT3A) ICD assembles into stable pentamers in solution in the absence of the other two domains, thought to be the drivers for oligomerization. Additionally, the soluble 5-HT3A-ICD construct interacted with the protein RIC-3 (resistance to inhibitors of cholinesterase). The interaction provides evidence that the 5-HT3A-ICD is not only required but also sufficient for interaction with RIC-3. Our results suggest the ICD constitutes an oligomerization domain. This novel role significantly adds to its known contributions in receptor trafficking, targeting, and functional fine-tuning. The innate diversity of the ICDs with sizes ranging from 50 to 280 amino acids indicates new methodologies need to be developed to determine the structures of these domains. The use of soluble ICD proteins that we report in the present study constitutes a useful approach to address this gap. PMID:27045630

  20. Shear strength in corner region of reinforced concrete duct type structures to be embedded in soil

    Reinforced concrete ducts for accommodating emergency cooling water pipes are generally embedded in soil. The structures is classified as one of the most important structures in terms of earthquake resistant design. During a strong earthquake it is subjected to shear deformations in concerted movement with surrounding soil. The comer regions of the duct should be designed against shear with moment combined. However, the complicated stress conditions in the region render the design more intricate in comparison with the case of simple determinate RC beam type structures. With the above situation in mind an experimental study was conducted, in which prototype as well as one half scale models representing the stress conditions in the region of interest were loaded and brought to failure in shear. The cross section of the prototype test model without shear reinforcements was 60 (height) x 30cm (width), and the tensile reinforcement ratio was 2.58%. The following results were obtained within the limit of the experimental study. (1) The shear capacity predicted by Japanese Design Code for linear RC members over-estimated the experimental ones with a considerably large safety margin of 4.4-5.0. (2) An improved design procedure to be applied to the specific structure was proposed, which gave a reasonable safety factor against shear failure of 1.7-2.0. (3) Combined smeared and discrete cracking model was utilized to simulate the shear failure mechanism, which could realistically pursue experimental behaviors. (author)

  1. UNIFIED CONTROL STRUCTURE OF MULTI-TYPE INTERIOR PERMANENT MAGNET MOTOR

    M. NORHISAM

    2015-03-01

    Full Text Available This paper presents the control strategy structure to extract the speed torque characteristic for the newly designed three phase Multi Type Interior Permanent Magnet Motor. The proposed structure with the driving circuits exhibit the performance of torque characteristics of the stepper motor and brushless motor with independent coil winding per phase especially used as an in-wheel motor in agricultural applications. Brushless Direct Current motors exhibit characteristics of generating high torque at high speed while the Permanent Magnet Stepper motors has characteristic of generating high torque at low speed. The typical characteristics of the above two are integrated in the proposed structure with a complex control structure that handle the switching complexity and speed control in real time. Thus, a specially designed driving system is essential to drive and control this special motor. The evaluation of the motor mechanical characteristics when applying load torque is also presented. The result determines the practical torque range applicable for each motor configuration and as combined machine.

  2. The solar type protostar IRAS16293-2422: new constraints on the physical structure

    Crimier, Nicolas; Maret, Sebastien; Bottinelli, Sandrine; Caux, Emmanuel; Kahane, Claudine; Lis, Dariusz C; Olofsson, Johan

    2010-01-01

    Context: The low mass protostar IRAS16293-2422 is a prototype Class 0 source with respect to the studies of the chemical structure during the initial phases of life of Solar type stars. Aims: In order to derive an accurate chemical structure, a precise determination of the source physical structure is required. The scope of the present work is the derivation of the structure of IRAS16293-2422. Methods: We have re-analyzed all available continuum data (single dish and interferometric, from millimeter to MIR) to derive accurate density and dust temperature profiles. Using ISO observations of water, we have also reconstructed the gas temperature profile. Results: Our analysis shows that the envelope surrounding IRAS16293-2422 is well described by the Shu "inside-out" collapsing envelope model or a single power-law density profile with index equal to 1.8. In contrast to some previous studies, our analysis does not show evidence of a large (>/- 800 AU in diameter) cavity. Conclusions: Although IRAS16293-2422 is a ...

  3. Structural and functional cardiac changes in myotonic dystrophy type 1: a cardiovascular magnetic resonance study

    Hermans Mieke CE

    2012-07-01

    Full Text Available Abstract Background Myotonic dystrophy type 1 (MD1 is a neuromuscular disorder with potential involvement of the heart and increased risk of sudden death. Considering the importance of cardiomyopathy as a predictor of prognosis, we aimed to systematically evaluate and describe structural and functional cardiac alterations in patients with MD1. Methods Eighty MD1 patients underwent physical examination, electrocardiography (ECG, echocardiography and cardiovascular magnetic resonance (CMR. Blood samples were taken for determination of NT-proBNP plasma levels and CTG repeat length. Results Functional and structural abnormalities were detected in 35 patients (44%. Left ventricular systolic dysfunction was found in 20 cases, left ventricular dilatation in 7 patients, and left ventricular hypertrophy in 6 patients. Myocardial fibrosis was seen in 10 patients (12.5%. In general, patients had low left ventricular mass indexes. Right ventricular involvement was uncommon and only seen together with left ventricular abnormalities. Functional or structural cardiac involvement was associated with age (p = 0.04, male gender (p Conclusions CMR can be useful to detect early structural and functional myocardial abnormalities in patients with MD1. Myocardial involvement is strongly associated with conduction abnormalities, but a normal ECG does not exclude myocardial alterations. These findings lend support to the hypothesis that MD1 patients have a complex cardiac phenotype, including both myocardial and conduction system alteration.

  4. Fine-Scale Phylogeographic Structure of Borrelia lusitaniae Revealed by Multilocus Sequence Typing

    Vitorino, Liliana R.; Margos, Gabriele; Feil, Edward J.; Collares-Pereira, Margarida; Zé-Zé, Libia; Kurtenbach, Klaus

    2008-01-01

    Borrelia lusitaniae is an Old World species of the Lyme borreliosis (LB) group of tick-borne spirochetes and prevails mainly in countries around the Mediterranean Basin. Lizards of the family Lacertidae have been identified as reservoir hosts of B. lusitaniae. These reptiles are highly structured geographically, indicating limited migration. In order to examine whether host geographic structure shapes the evolution and epidemiology of B. lusitaniae, we analyzed the phylogeographic population structure of this tick-borne bacterium using a recently developed multilocus sequence typing (MLST) scheme based on chromosomal housekeeping genes. A total of 2,099 questing nymphal and adult Ixodes ricinus ticks were collected in two climatically different regions of Portugal, being ∼130 km apart. All ticks were screened for spirochetes by direct PCR. Attempts to isolate strains yielded 16 cultures of B. lusitaniae in total. Uncontaminated cultures as well as infected ticks were included in this study. The results using MLST show that the regional B. lusitaniae populations constitute genetically distinct populations. In contrast, no clear phylogeographic signals were detected in sequences of the commonly used molecular markers ospA and ospC. The pronounced population structure of B. lusitaniae over a short geographic distance as captured by MLST of the housekeeping genes suggests that the migration rates of B. lusitaniae are rather low, most likely because the distribution of mediterranean lizard populations is highly parapatric. The study underlines the importance of vertebrate hosts in the geographic spread of tick-borne microparasites. PMID:19104655

  5. Temperature dependence of the local structure and lattice dynamics of wurtzite-type ZnO

    Temperature-dependent (10–300 K) Zn K-edge extended X-ray absorption fine structure (EXAFS) spectra of polycrystalline wurtzite-type ZnO were analyzed using ab initio multiple-scattering theory and taking into account anisotropy of the crystallographic structure and thermal disorder. We employed two different simulation approaches: classical molecular dynamics (MD) and reverse Monte Carlo coupled with an evolutionary algorithm (RMC/EA method). The accuracy of several force-field models, which are commonly used in the MD simulations of bulk and nanostructured ZnO, was tested based on a comparison between the experimental and simulated Zn K-edge EXAFS spectra. It was found that available force-field models fail to describe accurately many-atom distribution functions. A more accurate solution was obtained with the RMC/EA method, which allowed us also to resolve the non-equivalent groups of atoms in the first two coordination shells around the absorbing Zn atom and to follow the changes of structural parameters as the temperature varied. It was found that upon increasing temperature the structure of ZnO becomes more anisotropic due to the increase of internal parameter u of the oxygen Wyckoff position (2b) and related Zn0–O2 distances

  6. Structure of a microsporidian methionine aminopeptidase type 2 complexed with fumagillin and TNP-470

    Alvarado, J.; Nemkal, A; Sauder, J; Russell, M; Akiyoshi, D; Shi, W; Almo, S; Weiss, L

    2009-01-01

    Microsporidia are protists that have been reported to cause infections in both vertebrates and invertebrates. They have emerged as human pathogens particularly in patients that are immunosuppressed and cases of gastrointestinal infection, encephalitis, keratitis, sinusitis, myositis and disseminated infection are well described in the literature. While benzimidazoles are active against many species of microsporidia, these drugs do not have significant activity against Enterocytozoon bieneusi. Fumagillin and its analogues have been demonstrated to have activity in vitro and in animal models of microsporidiosis and human infections due to E. bieneusi. Fumagillin and its analogues inhibit methionine aminopeptidase type 2. Encephalitozoon cuniculi MetAP2 (EcMetAP2) was cloned and expressed as an active enzyme using a baculovirus system. The crystal structure of EcMetAP2 was determined with and without the bound inhibitors fumagillin and TNP-470. This structure classifies EcMetAP2 as a member of the MetAP2c family. The EcMetAP2 structure was used to generate a homology model of the E. bieneusi MetAP2. Comparison of microsporidian MetAP2 structures with human MetAP2 provides insights into the design of inhibitors that might exhibit specificity for microsporidian MetAP2.

  7. Oxide-ion conduction and dielectric relaxations for fluorite type structure

    Yagi, Yuhji; Kawamoto, Jun-ichi; Saito, Miwa; Yamamura, Hiroshi, E-mail: r200870209bq@kanagawa-u.ac.jp [Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama 221-8686 (Japan)

    2011-06-15

    The oxide-ion conduction and dielectric properties of 10 mol% CaO stabilized ZrO{sub 2} (10CSZ) and 25 mol% Y{sub 2}O{sub 3} stabilized Bi{sub 2}O{sub 3} (25YSB) which are oxide ion conductors having a fluorite-type structure were investigated. The numerical analyses for the frequency dependences of dielectric constants ({epsilon}{sub r}') and dielectric loss factors ({epsilon}{sub r}'') revealed that the dielectric properties were explained by Debye-type polarization due to dopant-vacancy associates and/or electrolyte-electrode interfacial polarization due to charging or loss current. No Debye-type polarization was observed in 25YSB because of no effective charge at the Y{sup 3+}-doped Bi{sup 3+} site. On the other hand, two Debye-type dipoles observed in 10CSZ were assigned to two kinds of associates, [Ca{sub Zr}''-V{sub o}{sup {center_dot}{center_dot}}]{center_dot}, which was due to dopant-vacancy associates with two different distances between (Ca{sub Zr}'') and (V{sub o}{sup {center_dot}{center_dot}}). The frequency dependence of dielectric loss tangent (tan{delta}) in 25YSB was ascribed to the interface loss due to the charged current, while that of tan{delta} in 8YSZ was ascribed to the Debye-type dipoles in addition to the interface loss.

  8. Local structure and effective pair potential of rock-salt type and disordered rock-salt type AgI under pressure

    X-ray absorption fine structure (XAFS) observations on iodine K edge of AgI have been performed under high pressure and high temperature up to 6.0 GPa and 1000K to investigate the local structure and effective potentials in high pressure phases. In EXAFS analysis, we have directly carried out the numerical integration of EXAFS function. The anharmonic effective pair potentials V(u)=au2/2+bu3/3! for I-Ag bond have been determined under pressures. α-AgI and disordered rock-salt type phase have super-ionic conduction behaviors. Ag ions occupy both octahedral and tetrahedral sites in the disordered phase and twenty percent of Ag ions occupy the tetrahedral site as a maximum value at 2GPa. The transition between the rock-salt type and disordered rock-salt type phases is a broad disorder type within the same structure. From the viewpoint of the local structure analyses on XANES and EXAFS spectra, some sudden changes are recognized near the phase transition point. Pressure influences greatly the effective pair potential of anti-bonding side and anharmonicity decreases with increasing pressure. Phonon dispersion relation of the rock-salt type AgI under pressure has been derived from EXAFS experiments. Analysis of EXAFS Debye-Waller factor is useful because the force constant can be decided directly even at high pressure and high temperature

  9. Multivalent ion conducting solids

    Imanaka, N. [Osaka Univ., Suita, Osaka (Japan). Dept. of Applied Chemistry

    2008-07-01

    Solid electrolytes possess important characteristics for industrial applications. Only a single ionic species can macroscopically migrate in these solids. This paper described a the new NASICON (M-Zr-Nb-P-O) type system, exhibiting an exceptionally high level of trivalent M3+ ion conductivity on polycrystalline solids. The partial substitution of the smaller higher valent Nb5+ ion for Zr4+ stabilized the NASICON phase and realized the M3+ ion conduction in the NASICON structure. It was concluded that the conductivities of the series are comparable to those of the practically applied solid electrolytes of oxide anion conductors of YSZ and CSZ. 3 refs., 2 figs.

  10. Crystal structure of Eu-doped magnetoplumbite-type lanthanum aluminum oxynitride with emission site splitting

    Eu-doped lanthanum aluminum oxynitride (LaAl12(O,N)19) with magnetoplumbite structure was prepared by nitridation of the oxide precursor obtained from aluminum glycine gel and subsequent post-annealing. Eu-doped lanthanum aluminum oxynitride exhibited blue light emission at 440 nm with a shoulder at 464 nm under excitation at 254 nm. Isostructural Eu-doped calcium aluminum oxide (CaAl12O19) exhibited a single emission peak at 415 nm. Structural refinement using neutron powder diffraction indicated that the lanthanum site occupied partially by Eu2+ splits into 2d and 6h sites in the aluminum oxynitride. The longer emission and the shoulder peak in the former aluminum oxynitride were observed in relation to the increasing covalency as well as crystal field splitting around doped Eu2+ induced by site splitting involved with the two kinds of anions. - Graphical Abstract: Magnetoplumbite type Eu-doped lanthanum aluminum oxynitride has lanthanum site splitting induced by two kinds of anions, causing two emission peaks. Highlights: ? Magnetoplumbite type LaAl12(O,N)19 doped with Eu shows emission peak splitting. ? ND analysis is performed on La0.97Eu0.03Al12(O,N)19 and Ca0.97Eu0.03Al12O19. ? La0.97Eu0.03Al12(O,N)19 has lanthanum site splitting. ? The lanthanum site splitting is induced by coexisting of two kinds of anions.

  11. Nuclear structure and the fate of core collapse (Type II) supernova

    For a long time Gerry Brown and his collaborator Hans Bethe considered the question of the final fate of a core collapse (Type II) supernova. Recalling ideas from nuclear structure on Kaon condensate and a soft equation of state of the dense nuclear matter they concluded that progenitor stars with mass as low as 17–18M⊙ (including supernova 1987A) could collapse to a small mass black hole with a mass just beyond 1.5M⊙, the upper bound they derive for a neutron star. We discuss another nuclear structure effect that determines the carbon to oxygen ratio (C/O) at the end of helium burning. This ratio also determines the fate of a Type II supernova with a carbon rich progenitor star producing a neutron star and oxygen rich collapsing to a black hole. While the C/O ratio is one of the most important nuclear inputs to stellar evolution it is still not known with sufficient accuracy. We discuss future efforts to measure with gamma-beam and TPC detector of the 12C(α,γ)16O reaction that determines the C/O ratio in stellar helium burning

  12. Nuclear structure and the fate of core collapse (Type II) supernova

    Gai, Moshe

    2014-08-01

    For a long time Gerry Brown and his collaborator Hans Bethe considered the question of the final fate of a core collapse (Type II) supernova. Recalling ideas from nuclear structure on Kaon condensate and a soft equation of state of the dense nuclear matter they concluded that progenitor stars with mass as low as 17-18M⊙ (including supernova 1987A) could collapse to a small mass black hole with a mass just beyond 1.5M⊙, the upper bound they derive for a neutron star. We discuss another nuclear structure effect that determines the carbon to oxygen ratio (C/O) at the end of helium burning. This ratio also determines the fate of a Type II supernova with a carbon rich progenitor star producing a neutron star and oxygen rich collapsing to a black hole. While the C/O ratio is one of the most important nuclear inputs to stellar evolution it is still not known with sufficient accuracy. We discuss future efforts to measure with gamma-beam and TPC detector of the C12(α,γ)O16 reaction that determines the C/O ratio in stellar helium burning.

  13. Nuclear Structure and the Fate of Core Collapse (Type II) Supernova

    Gai, Moshe

    2014-01-01

    For a long time Gerry Brown and his collaborator Hans Bethe considered the question of the final fate of a core collapse (Type II) supernova. Recalling ideas from nuclear structure on Kaon condensate and a soft equation of state of the dense nuclear matter they concluded that progenitor stars with mass as low a 17-18M$_\\odot$ (including supernova 1987A) could collapse to a small mass black hole with a mass just beyond 1.5M$_\\odot$, the upper bound they derive for a neutron star. We discuss another nuclear structure effect that determines the carbon to oxygen ratio (C/O) at the end of helium burning. This ratio also determines the fate of a Type II supernova with a carbon rich progenitor star producing a neutron star and oxygen rich collapsing to a black hole. While the C/O ratio is one of the most important nuclear input to stellar evolution it is still not known with sufficient accuracy. We discuss future efforts to measure with gamma-beam and TPC detector the 12C(a,g)16O reaction that determines the C/O rat...

  14. Characteristics of sandwich-type structural elements built of advanced composite materials from three dimensional fabrics

    Castejón, L.

    1997-12-01

    Full Text Available Sandwich-type structures have proved to be alternatives of great success for several fields of application, and specially in the building sector. This is due to their outstanding properties of .specific rigidity and strength against bending loads and other range of advantages like fatigue and impact resistance, attainment of flat and smooth surfaces, high electric and thermal insulation, design versatility and some others. However, traditional sandwich structures present problems like their tendency towards delamination, stress concentrations in bores or screwed Joints, and pre resistance. These problems are alleviated thanks to the use of new sandwich structures built using three dimensional structures of advanced composite materials, maintaining the present advantages for more traditional sandwich structures. At this rate, these new structures can be applied in several areas where conventional sandwich structures used to be like walls, partitions, floor and ceiling structures, domes, vaults and dwellings, but with greater success.

    Las estructuras tipo sándwich han demostrado ser alternativas de gran éxito para diversos campos de aplicación y, en concreto, en el sector de la construcción, listo es gracias a sus excelentes propiedades de rigidez y resistencia específica frente a cargas de flexión y otra larga lista de ventajas, a la que pertenecen, por ejemplo, su buena resistencia a fatiga, resistencia al impacto, obtención de superficies lisas y suaves, elevado aislamiento térmico y eléctrico, versatilidad de diseño y otras. Sin embargo, las estructuras sándwich, tradicionales presentan una problemática consistente en su tendencia a la delaminación, concentraciones de tensiones ¿aparecidas ante la existencia de agujeros o uniones atornilladas y resistencia al fuego. Estos problemas son pifiados gracias a la aplicación de estructuras novedosas tipo sándwich, construidas a partir de tejidos tridimensionales de materiales compuestos avanzados, manteniéndose las ventajas existentes para las estructuras sándwich tradicionales. De este modo, estas nuevas estructuras pueden ser aplicadas en diversas áreas donde se venían aplicando las estructuras sándwich convencionales, pero con mayor éxito. Como son muros, tabiques, suelos, bóvedas, cúpulas, estructuras de suelo y techo y viviendas.

  15. Types of structural chromosome aberrations and their incidences in human spermatozoa X-irradiated in vitro

    The authors studied the effects of in vitro X-irradiation on human sperm chromosomes, using our interspecific in vitro fertilization system between human spermatozoa and zona-free hamster oocytes. 28 semen samples from 5 healthy men were exposed to 0.23, 0.45, 0.91 and 1.82 Gy of X-rays. Totals of 2098 and 2862 spermatozoa were karyotyped in the control and the irradiated groups, respectively. The indicence of spermatozoa with X-ray-induced structural chromosome aberrations (Y) increased linearly with increasing dosage (D), being best expressed by the equation, Y = 0.08 + 34.52 D. The incidence of breakage-type aberrations was moe than 9 times higher than that of exchange-type aberrations. Both of them showed linear dose-dependent increases, which were expressed by the regression lines, Y = -0.014 + 0.478 D and Y -0.010 + 0.057 D, respectively. The incidence of chromosome-ltype aberrations was about 6 times higher than that of chromatid-type aberrations. Their dose-dependent increases were expressed by the regression lines, Y = -0.015 + 0.462 D and Y = -0.006 + 0.079 D, respectively. These results are discussed in relation to the previous data obtained with γ-rays. The repair mechanism of X-ray-induced sperm DNA lesions is also discussed. (author). 21 refs.; 4 figs.; 4 tabs

  16. A method for evaluating structural transducers used in Type B package testing

    Madsen, Marcella M.; Uncapher, William L.; Bronowski, David R.; Stenberg, Duane R.

    1989-01-01

    As a result of an agreement between DOE and the Nuclear Regulatory Commission (NRC), each transport cask must be certified by the NRC. To meet these requirements, OCRWM is undertaking a program to design, test, certify, and fabricate a variety of cask systems. Design verification tests will be performed by the cask contractor to demonstrate design safety and to aid in cask certification by the NRC. During Type B packaging design verification testing designers may verify analytical calculations with instrumentation data. Many packagings are tested with accelerometers and strain gages, collectively known as transducers, that measure structural response. Accelerometers measure acceleration and strain gages measure surface strain at the mounted location. This paper describes a method developed for OCRWM to evaluate various transducers of these two types that have been suggested for use in design verification testing. Typically transducers are characterized by the manufacturer under laboratory conditions. In this program ruggedness, failure frequency, repeatability, and manufacturer's data under field and laboratory conditions were investigated. Specific cask model test require transducers with specific ranges; transducers of the selected types were procured with ranges appropriate for this test.

  17. Determination of protein folding kinetic types using sequence and predicted secondary structure and solvent accessibility.

    Zhang, Hua; Zhang, Tuo; Gao, Jianzhao; Ruan, Jishou; Shen, Shiyi; Kurgan, Lukasz

    2012-01-01

    Proteins fold through a two-state (TS), with no visible intermediates, or a multi-state (MS), via at least one intermediate, process. We analyze sequence-derived factors that determine folding types by introducing a novel sequence-based folding type predictor called FOKIT. This method implements a logistic regression model with six input features which hybridize information concerning amino acid composition and predicted secondary structure and solvent accessibility. FOKIT provides predictions with average Matthews correlation coefficient (MCC) between 0.58 and 0.91 measured using out-of-sample tests on four benchmark datasets. These results are shown to be competitive or better than results of four modern predictors. We also show that FOKIT outperforms these methods when predicting chains that share low similarity with the chains used to build the model, which is an important advantage given the limited number of annotated chains. We demonstrate that inclusion of solvent accessibility helps in discrimination of the folding kinetic types and that three of the features constitute statistically significant markers that differentiate TS and MS folders. We found that the increased content of exposed Trp and buried Leu are indicative of the MS folding, which implies that the exposure/burial of certain hydrophobic residues may play important role in the formation of the folding intermediates. Our conclusions are supported by two case studies. PMID:21082205

  18. Synthesis, structural transformation, thermal stability, valence state, and magnetic and electronic properties of PbNiO3 with perovskite- and LiNbO3-type structures.

    Inaguma, Yoshiyuki; Tanaka, Kie; Tsuchiya, Takeshi; Mori, Daisuke; Katsumata, Tetsuhiro; Ohba, Tomonori; Hiraki, Ko-ichi; Takahashi, Toshihiro; Saitoh, Hiroyuki

    2011-10-26

    We synthesized two high-pressure polymorphs PbNiO(3) with different structures, a perovskite-type and a LiNbO(3)-type structure, and investigated their formation behavior, detailed structure, structural transformation, thermal stability, valence state of cations, and magnetic and electronic properties. A perovskite-type PbNiO(3) synthesized at 800 °C under a pressure of 3 GPa crystallizes as an orthorhombic GdFeO(3)-type structure with a space group Pnma. The reaction under high pressure was monitored by an in situ energy dispersive X-ray diffraction experiment, which revealed that a perovskit-type phase was formed even at 400 °C under 3 GPa. The obtained perovskite-type phase irreversibly transforms to a LiNbO(3)-type phase with an acentric space group R3c by heat treatment at ambient pressure. The Rietveld structural refinement using synchrotron X-ray diffraction data and the XPS measurement for both the perovskite- and the LiNbO(3)-type phases reveal that both phases possess the valence state of Pb(4+)Ni(2+)O(3). Perovskite-type PbNiO(3) is the first example of the Pb(4+)M(2+)O(3) series, and the first example of the perovskite containing a tetravalent A-site cation without lone pair electrons. The magnetic susceptibility measurement shows that the perovskite- and LiNbO(3)-type PbNiO(3) undergo antiferromagnetic transition at 225 and 205 K, respectively. Both the perovskite- and LiNbO(3)-type phases exhibit semiconducting behavior. PMID:21888429

  19. Structures and properties of ThCr2Si2-type superconductors and related materials

    Work on this thesis started in 2008, only a few months after the discovery of superconductivity in doped BaFe2As2. The first goal at that time was the investigation of further compounds crystallizing in the ThCr2Si2-type structure with respect to phase transitions, magnetic properties and possible superconductivity. One candidate that seemed to be very similar to BaFe2As2 because of its structural phase transitions, was SrRh2As2. However, a closer look revealed a more complicated and challenging structural chemistry. The first two chapters of this work are devoted to the study and solution of the intriguing crystallographic problems of the three SrRh2As2 phases and the characterization of further ternary rhodium arsenides. Furthermore, high quality single crystals of Ba1-xKxFe2As2 were synthesized and single crystals as well as powder samples of Ba1-xKxFe2As2 were investigated with synchrotron X-ray diffraction methods as described in chapters 5 and 6. Finally, the last part of this thesis concentrates on the question which effects of doping are actually responsible for the occurrence of superconductivity in BaFe2As2. Is the superconductivity induced by the alteration of charge in the FeAs4/4-layer, by the disorder introduced by doping, or by the structural changes? To help elucidate this issue, several substitution series of 122-iron arsenides were prepared and the influence of hole and electron or charge and isoelectronic doping on superconductivity, magnetic and structural properties and their mutual relationship was studied (chapters 7,8,9 and 10).

  20. High-pressure synthesis of ferromagnetic Mn sub 3 Ge with the Cu sub 3 Au-type structure

    Takizawa, H; Uheda, K; Endo, T

    2002-01-01

    A new intermetallic compound, Mn sub 3 Ge, has been synthesized by direct reaction of elemental components at 6.2 GPa and 1000 deg. C for 30 min using a belt-type high-pressure apparatus. The compound crystallizes into a cubic structure with the space group Pm3m, namely the L1 sub 2 -type (Cu sub 3 Au-type) structure. The structure was refined by Rietveld analysis of the powder x-ray diffraction data and the lattice constant was determined as a = 0.380 19(3) nm. The compound shows metallic conductivity and ferromagnetism with a Curie temperature of 400 K.

  1. High-pressure synthesis of ferromagnetic Mn3Ge with the Cu3Au-type structure

    A new intermetallic compound, Mn3Ge, has been synthesized by direct reaction of elemental components at 6.2 GPa and 1000 deg. C for 30 min using a belt-type high-pressure apparatus. The compound crystallizes into a cubic structure with the space group Pm3m, namely the L12-type (Cu3Au-type) structure. The structure was refined by Rietveld analysis of the powder x-ray diffraction data and the lattice constant was determined as a = 0.380 19(3) nm. The compound shows metallic conductivity and ferromagnetism with a Curie temperature of 400 K

  2. Structure of a bacterial type III secretion system in contact with a host membrane in situ

    Nans, Andrea; Kudryashev, Mikhail; Saibil, Helen R.; Hayward, Richard D.

    2015-12-01

    Many bacterial pathogens of animals and plants use a conserved type III secretion system (T3SS) to inject virulence effector proteins directly into eukaryotic cells to subvert host functions. Contact with host membranes is critical for T3SS activation, yet little is known about T3SS architecture in this state or the conformational changes that drive effector translocation. Here we use cryo-electron tomography and sub-tomogram averaging to derive the intact structure of the primordial Chlamydia trachomatis T3SS in the presence and absence of host membrane contact. Comparison of the averaged structures demonstrates a marked compaction of the basal body (4 nm) occurs when the needle tip contacts the host cell membrane. This compaction is coupled to a stabilization of the cytosolic sorting platform-ATPase. Our findings reveal the first structure of a bacterial T3SS from a major human pathogen engaged with a eukaryotic host, and reveal striking `pump-action' conformational changes that underpin effector injection.

  3. Two Types of Dynamic Cool Coronal Structures Observed with STEREO and HINODE

    Zhang, J

    2009-01-01

    Solar coronal loops show significant plasma motions during their formation and eruption stages. Dynamic cool coronal structures, on the other hand, are often observed to propagate along coronal loops. In this paper, we report on the discovery of two types of dynamic cool coronal structures, and characterize their fundamental properties. Using the EUV 304 angstrom images from the Extreme UltraViolet Imager (EUVI) telescope on the Solar TErrestrial RElation Observatory (STEREO) and the Ca II filtergrams from the Solar Optical Telescope (SOT) instrument on HINODE, we study the evolution of an EUV arch and the kinematics of cool coronal structures. The EUV 304 angstrom observations show that a missile-like plasmoid moves along an arch-shaped trajectory, with an average velocity of 31 km/s. About three hours later, a plasma arch forms along the trajectory, subsequently the top part of the arch fades away and disappears, meanwhile the plasma belonging to the two legs of the arch flows downward to the arch feet. Dur...

  4. Optimization of chemical structure of Schottky-type selection diode for crossbar resistive memory.

    Kim, Gun Hwan; Lee, Jong Ho; Jeon, Woojin; Song, Seul Ji; Seok, Jun Yeong; Yoon, Jung Ho; Yoon, Kyung Jean; Park, Tae Joo; Hwang, Cheol Seong

    2012-10-24

    The electrical performances of Pt/TiO(2)/Ti/Pt stacked Schottky-type diode (SD) was systematically examined, and this performance is dependent on the chemical structures of the each layer and their interfaces. The Ti layers containing a tolerable amount of oxygen showed metallic electrical conduction characteristics, which was confirmed by sheet resistance measurement with elevating the temperature, transmission line measurement (TLM), and Auger electron spectroscopy (AES) analysis. However, the chemical structure of SD stack and resulting electrical properties were crucially affected by the dissolved oxygen concentration in the Ti layers. The lower oxidation potential of the Ti layer with initially higher oxygen concentration suppressed the oxygen deficiency of the overlying TiO(2) layer induced by consumption of the oxygen from TiO(2) layer. This structure results in the lower reverse current of SDs without significant degradation of forward-state current. Conductive atomic force microscopy (CAFM) analysis showed the current conduction through the local conduction paths in the presented SDs, which guarantees a sufficient forward-current density as a selection device for highly integrated crossbar array resistive memory. PMID:22999222

  5. Field characteristics of an alvarez-type linac structure having chain-like electrode array

    A chain-like electrode configuration in an Alvarez-type linac cavity was studied by models. The structure has been devised to get a moderate shunt impedance together with simplicity of operation, in ion velocity region of more than a few percent of that of light by incorporating focusing scheme by high frequency quadrupolar fields into an TM-010 accelerating field of an Alvarez linac. It has a chain-like electrode array instead of drift tubes containing quadrupole lenses for ordinary linacs. The chain-like electrode structure generates along its central axis, high frequency acceleration and focusing fields alternately, separating the acceleration and focusing functions in space. The separation discriminates this structure from spatially uniform acceleration and focusing scheme of the RFQs devised by Kapchinsky and Teplyakov. It gives beam acceleration effects different from those by conventional linacs and reveals possibility of getting a high acceleration efficiency. Resonant frequency spectrum was found relatively simple by measurements on high frequency models. Separation of unwanted modes from the TM-010 acceleration mode is large; a few 10 MHz, at least. Tilt of the acceleration field is not very sensitive to pertubation in gap capacitance for the TM-010 mode

  6. Enantiomer Discrimintation Illustrated by the High Resolution Crystal Structures of Type 4 Phosphodiesterase

    Huai,Q.; Sun, Y.; Wang, H.; MacDonald, D.; Aspiotis, R.; Robinson, H.; Huang, Z.; Ke, H.

    2006-01-01

    Type 4 phosphodiesterase (PDE4) inhibitors are emerging as new treatments for a number of disorders including asthma and chronic obstructive pulmonary disease. Here we report the biochemical characterization on the second generation inhibitor (+)-1 (L-869298, IC50 = 0.4 nM) and its enantiomer (-)-1 (L-869299, IC50 = 43 nM) and their cocrystal structures with PDE4D at 2.0 Angstroms resolution. Despite the 107-fold affinity difference, both enantiomers interact with the same sets of residues in the rigid active site. The weaker (-)-1 adopts an unfavorable conformation to preserve the pivotal interactions between the Mg-bound waters and the N-oxide of pyridine. These structures support a model in which inhibitors are anchored by the invariant glutamine at one end and the metal-pocket residues at another end. This model provides explanations for most of the observed structure-activity relationship and the metal ion dependency of the catechol-ether based inhibitors and should facilitate their further design.

  7. Crystal chemistry of Ruddlesden-Popper type structures in high Tc ceramic superconductors

    Similar structural patterns have been noticed in the systems La-Cu-O, La-Ni-O and Bi and Tl-containing superconducting oxides. The formation of Ruddlesden-Popper type layers (alternating slabs of rocksalt and perovskite strucutres) is seen in these oxides which is similar in many respects to what is seen in the system Sr-Ti-O. However, there are some significant differences, for example the rocksalt and perovskite blocks in new superconducting compounds are not necessarily electrically neutral, unlike in the Sr-Ti-O system. It, thus, becomes necessary to create oxygen vacancies in the basic perovskite structure of Bi-containing compounds, when the width of the perovskite slab changes on addition of extra Cu-O planes. Results of atomistic simulations suggest that these missing oxygen ions allows the Cu-O planes to buckle in Bi-series of compounds. This is also supported by the absence of buckling in the Sr-Ti-O series of compounds and the first member of Bi-containing compounds in which there are no missing oxygen ions. Additional results on the phase stability of polytypoid structure in la-Cu-O system and defect chemistry of compounds of LaNi-O system are presented. (author). 14 re fs., 7 figs., 4 tabs

  8. Crystallographic structure of porcine adenovirus type 4 fiber head and galectin domains.

    Guardado-Calvo, Pablo; Muñoz, Eva M; Llamas-Saiz, Antonio L; Fox, Gavin C; Kahn, Richard; Curiel, David T; Glasgow, Joel N; van Raaij, Mark J

    2010-10-01

    Adenovirus isolate NADC-1, a strain of porcine adenovirus type 4, has a fiber containing an N-terminal virus attachment region, shaft and head domains, and a C-terminal galectin domain connected to the head by an RGD-containing sequence. The crystal structure of the head domain is similar to previously solved adenovirus fiber head domains, but specific residues for binding the coxsackievirus and adenovirus receptor (CAR), CD46, or sialic acid are not conserved. The structure of the galectin domain reveals an interaction interface between its two carbohydrate recognition domains, locating both sugar binding sites face to face. Sequence evidence suggests other tandem-repeat galectins have the same arrangement. We show that the galectin domain binds carbohydrates containing lactose and N-acetyl-lactosamine units, and we present structures of the galectin domain with lactose, N-acetyl-lactosamine, 3-aminopropyl-lacto-N-neotetraose, and 2-aminoethyl-tri(N-acetyl-lactosamine), confirming the domain as a bona fide galectin domain. PMID:20686025

  9. Oxidative dehydrogenation of isobutyl alcohol over different structure type of zeolites

    Full text: Partial heterogen-catalytic of aliphatic alcohols is perspective method for production of important oxygen-containing compounds. Numerous of the literature data testify that the different mixed oxides of metals show the relatively high catalytic activity in the reactions of oxidation of aliphatic alcohols. Until recently however little attention had been given to the possibility of using of the modified zeolites for promoting these reactions. The present paper is devoted to oxidative dehydrogenation of isobutyl alcohol in the presence of molecular oxygen over different structure type of synthetical (A, X, Y, ZSM-5) and natural zeolites modified by cations of transition elements (Cu2+, Sn2+, Ni2+, Co2+, Fe2+ and Pd2+) for the purpose of selection of an active catalyst for production of corresponding aldehyde. For making of active catalyst on the first stage the study was carried out ever mono- and on the second stage over bimethalzeolite catalysts. It has been established that for each of zeolite has there optimum concentration of transition element cation in the dependence of structure of zeolites. It has been found that, the mono metallic catalysts on the basis of synthetical zeolites more active in this reaction than catalysts on the basis of natural zeolites. Introduction of second metal cation (Pd2+) into structure of mono metallic catalyst leaded considerable increasing of conversion of alcohol and selectivity of the process and stability of operation of catalysts

  10. Panchromatic modeling of structure and stellar population of early type galaxies

    Shao, Zhengyi; Chen, Zhendong

    2015-08-01

    We introduce a new approach to model the structure and stellar population of early type galaxies (ETGs). In this method, the mass distribution of stellar components in the galaxy is assumed directly, instead of that used in previous studies, which is the surface brightness profile of a specific wave band. Thus, multiple wavebands photometric data, from optical to NIR, can be used simultaneously to determine model parameters, such as the Sersic index and the size of galaxy structure, age, metallicity and their radial gradients of stellar population. The PSF effects of different wavebands are also considered in the model prediction, with which compare the observational photometric profiles. Also, information from fiber spectrum of the central part of a galaxy is very easy to be taken into account during the fitting process. Moreover, the Bayesian evidence (BE) is involved in the method to assess different empirical models, and help us to decide, for individual ETGs, if an extra outer disk structure is necessary to be added. Primary results show that, for most of ETGs from SDSS, they have negative color gradients, which means their stellar population in central part are older or metal richer than that in outer part, and this gradient is significantly correlated to the total stellar mass of the galaxy, more massive ETGs have shallower gradients. Additionally, the scaling relation of ETGs, such as their fundamental plane, is well constrained by their stellar mass distributions rather than by surface brightness profiles.

  11. NMR investigations of Li+ ion dynamics in the NASICON ionic conductors Li1-xLax/3□2x /3Zr2(PO4)3

    NMR studies of 7Li and 31P nuclei are reported in the 150-900 K temperature range for the Li1-xLax/3□2x /3Zr2(PO4)3 NASICON compounds with x = 0.8, 0.7, 0.6 and 0.3. Magic angle spinning (MAS mode) experiments were performed at room temperature on the 7Li and 31P nuclei. The linewidth and the spin lattice relaxation times of these nuclei are studied versus temperature in the static mode. The spectra recorded in the MAS mode show that the 7Li ions occupy three chemical sites, the occupation of which being very sensitive to the x values but not sensitive to the coexistence of the two varieties C1-bar and R3-barc observed at room temperature in compounds with x≤0.5. On the other hand, the 31P nucleus MAS spectra are very sensitive to lithium content but also to the variety coexistence. T1 measurements were performed in a static mode on the 7Li and 31P nuclei. In all the compounds, the 7Li spin lattice relaxation time exhibits two branches with several minima, indicating the complex dynamics for this ion. One of these minima appears in the same temperature range as the minimum of the 31P nucleus T1, strongly suggesting a cross-relaxation process between these nuclei. T1ρ measurements on 7Li (static mode) allow us to show a slow motion different from the one probed by the T1. The analysis of the T1ρ behaviour with temperature and composition allows us to ascribe the motion probed by this time to the oxygen ion motion which monitors the opening and closing of the lithium pathways. A qualitative interpretation of the 7Li T1 results is done; it takes into account the cross-relaxation phenomena between 31P and 7Li and quadrupolar fluctuations.

  12. The influence of type-I and type-II triplet multiple quantum well structure on white organic light-emitting diodes.

    Zhao, Bo; Su, Zisheng; Li, Wenlian; Chu, Bei; Jin, Fangming; Yan, Xingwu; Zhang, Tianyou; Zhang, Feng; Fan, Di; Gao, Yuan; Wang, Junbo; Pi, Huachun; Zhu, Jianzhuo

    2013-01-01

    We demonstrate high-efficient white organic light-emitting diodes (WOLEDs) based on triplet multiple quantum well (MQW) structure and focus on the influence on WOLEDs through employing different potential barrier materials to form type-I and type-II MQWs, respectively. It is found that type-I MQW structure WOLEDs based on 1,3,5-tris(N-phenyl-benzimidazol-2-yl)benzene as potential barrier layer (PBL) offers high electroluminescent (EL) performance. That is to say, maximum current efficiency and power efficiency are achieved at about 1,000cd/m2 with 16.4cd/A and 8.3lm/W, which increase by 53.3% and 50.9% over traditional three-layer structure WOLEDs, respectively, and a maximum luminance of 17,700cd/m2 is earned simultaneously. The achievement of high EL performance would be attributed to uniform distribution and better confinement of carriers within the emitting layer (EML). However, when 4,7-diphenyl-1,10-phenanthroline or 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline is used as PBL to form type-II MQW structure, poor EL performance is obtained. We attribute that to improper energy level alignment between the interface of EML/PBL, which leads to incomplete confinement and low recombination efficiency of carriers, a more detailed mechanism was argued. PMID:24341599

  13. How to Compare, Analyze, and Morph Between Crystal Structures of Different Conformations: The P-Type ATPase Example.

    Karlsen, Jesper L; Bublitz, Maike

    2016-01-01

    In the past 15 years, a large body of structural information on P-type ATPases has accumulated in the Protein Data Bank. The available crystal structures cover different enzymes in a variety of conformational states that are associated with the enzymatic activity of ATP-dependent ion translocation across membranes. This chapter provides an overview about the available structural information, along with some practical instructions on how to make meaningful comparisons of structures in different conformations, and how to generate morphs between series of structures, in order to analyze domain movements and structural flexibility. PMID:26695058

  14. Glomerular structural-functional relationship models of diabetic nephropathy are robust in type 1 diabetic patients.

    Mauer, Michael; Caramori, Maria Luiza; Fioretto, Paola; Najafian, Behzad

    2015-06-01

    Studies of structural-functional relationships have improved understanding of the natural history of diabetic nephropathy (DN). However, in order to consider structural end points for clinical trials, the robustness of the resultant models needs to be verified. This study examined whether structural-functional relationship models derived from a large cohort of type 1 diabetic (T1D) patients with a wide range of renal function are robust. The predictability of models derived from multiple regression analysis and piecewise linear regression analysis was also compared. T1D patients (n = 161) with research renal biopsies were divided into two equal groups matched for albumin excretion rate (AER). Models to explain AER and glomerular filtration rate (GFR) by classical DN lesions in one group (T1D-model, or T1D-M) were applied to the other group (T1D-test, or T1D-T) and regression analyses were performed. T1D-M-derived models explained 70 and 63% of AER variance and 32 and 21% of GFR variance in T1D-M and T1D-T, respectively, supporting the substantial robustness of the models. Piecewise linear regression analyses substantially improved predictability of the models with 83% of AER variance and 66% of GFR variance explained by classical DN glomerular lesions alone. These studies demonstrate that DN structural-functional relationship models are robust, and if appropriate models are used, glomerular lesions alone explain a major proportion of AER and GFR variance in T1D patients. PMID:25183630

  15. Structural basis for promiscuous PAM recognition in type I-E Cascade from E. coli.

    Hayes, Robert P; Xiao, Yibei; Ding, Fran; van Erp, Paul B G; Rajashankar, Kanagalaghatta; Bailey, Scott; Wiedenheft, Blake; Ke, Ailong

    2016-02-25

    Clustered regularly interspaced short palindromic repeats (CRISPRs) and the cas (CRISPR-associated) operon form an RNA-based adaptive immune system against foreign genetic elements in prokaryotes. Type I accounts for 95% of CRISPR systems, and has been used to control gene expression and cell fate. During CRISPR RNA (crRNA)-guided interference, Cascade (CRISPR-associated complex for antiviral defence) facilitates the crRNA-guided invasion of double-stranded DNA for complementary base-pairing with the target DNA strand while displacing the non-target strand, forming an R-loop. Cas3, which has nuclease and helicase activities, is subsequently recruited to degrade two DNA strands. A protospacer adjacent motif (PAM) sequence flanking target DNA is crucial for self versus foreign discrimination. Here we present the 2.45 Å crystal structure of Escherichia coli Cascade bound to a foreign double-stranded DNA target. The 5'-ATG PAM is recognized in duplex form, from the minor groove side, by three structural features in the Cascade Cse1 subunit. The promiscuity inherent to minor groove DNA recognition rationalizes the observation that a single Cascade complex can respond to several distinct PAM sequences. Optimal PAM recognition coincides with wedge insertion, initiating directional target DNA strand unwinding to allow segmented base-pairing with crRNA. The non-target strand is guided along a parallel path 25 Å apart, and the R-loop structure is further stabilized by locking this strand behind the Cse2 dimer. These observations provide the structural basis for understanding the PAM-dependent directional R-loop formation process. PMID:26863189

  16. Evidence for alternative quaternary structure in a bacterial Type III secretion system chaperone

    Barta, Michael L.; Zhang, Lingling; Picking, Wendy L.; Geisbrecht, Brian V. (UMKC); (OKLU)

    2010-10-05

    Type III secretion systems are a common virulence mechanism in many Gram-negative bacterial pathogens. These systems use a nanomachine resembling a molecular needle and syringe to provide an energized conduit for the translocation of effector proteins from the bacterial cytoplasm to the host cell cytoplasm for the benefit of the pathogen. Prior to translocation specialized chaperones maintain proper effector protein conformation. The class II chaperone, Invasion plasmid gene (Ipg) C, stabilizes two pore forming translocator proteins. IpgC exists as a functional dimer to facilitate the mutually exclusive binding of both translocators. In this study, we present the 3.3 {angstrom} crystal structure of an amino-terminally truncated form (residues 10-155, denoted IpgC10-155) of the class II chaperone IpgC from Shigella flexneri. Our structure demonstrates an alternative quaternary arrangement to that previously described for a carboxy-terminally truncated variant of IpgC (IpgC{sup 1-151}). Specifically, we observe a rotationally-symmetric 'head-to-head' dimerization interface that is far more similar to that previously described for SycD from Yersinia enterocolitica than to IpgC1-151. The IpgC structure presented here displays major differences in the amino terminal region, where extended coil-like structures are seen, as opposed to the short, ordered alpha helices and asymmetric dimerization interface seen within IpgC{sup 1-151}. Despite these differences, however, both modes of dimerization support chaperone activity, as judged by a copurification assay with a recombinant form of the translocator protein, IpaB. Conclusions: From primary to quaternary structure, these results presented here suggest that a symmetric dimerization interface is conserved across bacterial class II chaperones. In light of previous data which have described the structure and function of asymmetric dimerization, our results raise the possibility that class II chaperones may transition between asymmetric and symmetric dimers in response to changes in either biochemical modifications (e.g. proteolytic cleavage) or other biological cues. Such transitions may contribute to the broad range of protein-protein interactions and functions attributed to class II chaperones.

  17. Evidence for alternative quaternary structure in a bacterial Type III secretion system chaperone

    Picking Wendy L

    2010-07-01

    Full Text Available Abstract Background Type III secretion systems are a common virulence mechanism in many Gram-negative bacterial pathogens. These systems use a nanomachine resembling a molecular needle and syringe to provide an energized conduit for the translocation of effector proteins from the bacterial cytoplasm to the host cell cytoplasm for the benefit of the pathogen. Prior to translocation specialized chaperones maintain proper effector protein conformation. The class II chaperone, Invasion plasmid gene (Ipg C, stabilizes two pore forming translocator proteins. IpgC exists as a functional dimer to facilitate the mutually exclusive binding of both translocators. Results In this study, we present the 3.3 Å crystal structure of an amino-terminally truncated form (residues 10-155, denoted IpgC10-155 of the class II chaperone IpgC from Shigella flexneri. Our structure demonstrates an alternative quaternary arrangement to that previously described for a carboxy-terminally truncated variant of IpgC (IpgC1-151. Specifically, we observe a rotationally-symmetric "head-to- head" dimerization interface that is far more similar to that previously described for SycD from Yersinia enterocolitica than to IpgC1-151. The IpgC structure presented here displays major differences in the amino terminal region, where extended coil-like structures are seen, as opposed to the short, ordered alpha helices and asymmetric dimerization interface seen within IpgC1-151. Despite these differences, however, both modes of dimerization support chaperone activity, as judged by a copurification assay with a recombinant form of the translocator protein, IpaB. Conclusions From primary to quaternary structure, these results presented here suggest that a symmetric dimerization interface is conserved across bacterial class II chaperones. In light of previous data which have described the structure and function of asymmetric dimerization, our results raise the possibility that class II chaperones may transition between asymmetric and symmetric dimers in response to changes in either biochemical modifications (e.g. proteolytic cleavage or other biological cues. Such transitions may contribute to the broad range of protein-protein interactions and functions attributed to class II chaperones.

  18. The response of the pyrochlore structure-type to ion-beam irradiation

    Lian, Jie

    Pyrochlore with the general formula of A3+2B4+2O7 (Fd3m; Z = 8) has been proposed as the candidate waste form for the immobilization of actinides, particularly plutonium from dismantled nuclear weapons. Because actinides decay by alpha-decay events, radiation effects on the waste form are a concern. The effects of radiation on different pyrochlore compositions, A2B2O7 (A = La Lu, and Y; B = Ti, Sn, and Zr), have been investigated by 50 KeV He+, 600 KeV Ar+, 1.0 MeV Kr+, and 1.5 MeV Xe+ ion irradiations. Titanate pyrochlores are generally sensitive to ion beam damage and can be amorphized at a low damage level (0.2 dpa). The critical amorphization temperature, Tc, increases from 480 to 1120 K with increasing A-site cation size. A dramatically increasing radiation "resistance" to ion beam induced-amorphization has been observed with increasing Zr-content in the Gd2Ti2-xZrxO7 system. The pure end-member, Gd2Zr2O7, cannot be amorphized, even at doses as high as 100 dpa. Although zirconate pyrochlores are generally considered to be radiation "resistant", ion beam-induced amorphization occurs for La2Zr2O7 at a dose of 5.5 dpa at room temperature. Stannate pyrochlores A2Sn 2O7 (A = La, Nd, Gd) are readily amorphized by ion beam damage at a relatively low dose (1 dpa) at room temperature; while no evidence of amorphization has been observed in A2Sn2O7 (A = Er, Y, Lu) irradiated with 1 MeV Kr+ ions at a dose of 6 dpa at 25 K. The factors that influence the response of different pyrochlore compositions to ion irradiation-induced amorphization are discussed in terms of cation radius ratio, defect formation energies, and the tendency of the pyrochlore structure-type to undergo an order-disorder transition to the defect-fluorite structure. The "resistance" of the pyrochlore structure to ion beam-induced amorphization is not only affected by the relative sizes of the A- and B-site cations, but also the cation electronic configurations. Pyrochlore compositions that have larger structural deviations from the ideal fluorite structure are more sensitive to ion beam-induced amorphization. These fundamental results provide insight into the structural and compositional controls on radiation-induced amorphization of pyrochlores. This understanding can be used for the design and selection of materials used for the immobilization of actinides.

  19. Electronic structure of F type color center in MgO and optical absorption transition

    The electronic structure of MgO crystal with F type color center has been studied with the relaxation of ions around vacancy by using the SCC-DVM-Xα methods. The energy band, bulk density of states have been calculated. Also, the optic transition model has been discussed. The calculation results showed that F, F+ and F2+-center in MgO crystal introduced defect energy levels in the forbidden gap. The calculated absorption energies for F and F+-center were 4.67eV and 4.66eV, respectively. Also, big photoelectron energies were required for F and F+-centers. The good agreement with experimental data showed the reasonableness of the calculated results

  20. Application of SMA rod to exposed-type column base in smart structural system

    Tamai, Hiroyuki; Miura, Kenji; Kitagawa, Yoshikazu; Fukuta, Toshibumi

    2003-08-01

    A seismic-resistant member with a shape memory alloy (SMA) rod was used in an exposed-type column base as a passive damper for building structures. Horizontal and vertical loading tests on the column base with SMA anchorage were done with increasing drift amplitude to investigate the restoring force characteristics of the column base. The results showed that (1) use of an SMA rod prevents deterioration of the restoring force characteristics, (2) use of an appropriate SMA material and a moderate-size rod can yield large deformation capacity and good restoring force characteristics, and (3) after a large drift in the building frame, SMA anchorage enables the original shape and resisting performance to recover with unloading.

  1. Euler Poincaré flows and leibniz structure of nonlinear reaction diffusion type systems

    Guha, Partha

    2006-09-01

    In this paper we present Euler-Poincaré formulation of the Fisher, Fitzhugh-Nagumo, Burgers-Huxley and extended Fitzhugh-Nagumo and extended Burgers-Huxley type nonlinear reaction-diffusion systems. All these flows are related to infinite dimensional almost Poisson manifolds and the corresponding Lie-Poisson structures yield Leibniz brackets, a bracket endowed with both symmetric and skewsymmetric parts. The symmetric part contributes the diffusion part of the ssystem. The properties exhibited by the reaction-diffusion systems defined in this way are in general very different from the standard Hamiltonian mechanics since the dynamics are controlled by the standard Poisson brackets. Moreover, all the nonlinear reaction-diffusion systems under consideration are Euler-Poincaré flows on the dual of Kirillov's superalgebra associated to the Bott-Virasoro group.

  2. Genetic-Structural relations in some types of spanish uranium deposits

    On the spanish hercynian areas there are different types of uraniferous deposits, which may be classified in the following groups: Group I, high temperature magmatic deposits, Group II, low temperature veins and Group III supergenic deposits, generated by weathering of the former ones or by lixiviation of the intra granitic uranium. The deposits belonging to Group I are founding the hercynian ge anticlinal; those of Groups II and III, chiefly in the eugeosyncline. The explanation suggested for these genetic-structural relationships assumes that, in the ge anticlinal, uranium would migrate from the dioritic magmas to form and high temperature deposits. In the eugeosyncline, a large fraction of the uranium would migrate towards more differentiated granites, in which it might partially remain or from which it might have been finally concentrated in the epithermal veins or by later tectonic actions. The Group III deposits ar more frequent in the eugeosyncline, due to the greater abundance of more differentiated intrusive rocks. (Author) 16 refs

  3. Photoinduced domain-type collective structural changes with interlayer ? -bonds in the visible region of graphite

    Ohnishi, Hiromasa; Nasu, Keiichiro

    2009-02-01

    We theoretically study the photoinduced domain-type structural changes in the visible region of graphite. By means of the ab initio total-energy calculation, we clarify the adiabatic path for the nucleation of this domain, wherein the interlayer distance of the original graphite is contracted and new interlayer ? -bonds are induced with a certain periodic buckling pattern. We show that an excitation by few visible photons is energetically enough to trigger the formation of this domain, and this domain is sufficiently stable against the thermal fluctuation at around room temperature. The electronic state of this domain is also shown to have a pseudogap, characteristic to an insulator immersed in the original semimetallic graphite.

  4. Fine Structure of Type-I Edge-Localized Modes in the Steep Gradient Region

    Fast, high resolution multichannel Thomson scattering is used to quantitatively determine plasma perturbations induced by type-I edge-localized modes (ELMs) in the low-field side edge of ASDEX Upgrade H-mode plasmas. 2D snapshots of temperature and density, deduced from the laser light scattered in a vertically elongated, poloidal array of 5x10 scattering volumes, are obtained in the hot, steep edge gradient zone, which is difficult to access by other diagnostics. Local maxima and minima with large amplitude are identified during ELMs and even in the precursor phase, both in density and temperature. Interpreting these structures as footprints of approximately field aligned helical modes in accordance with previous experimental and theoretical work, toroidal mode numbers between 8 and 20 are obtained, roughly consistent with corresponding scrape-off layer and divertor measurements

  5. The effectiveness of structured personal care of type 2 diabetes on recurrent outcomes

    Lundström, Hanna Maria; Siersma, Volkert Dirk; Nielsen, Anni Brit Sternhagen; Brodersen, John; Reventlow, Susanne; Andersen, Per Kragh; Olivarius, Niels

    2014-01-01

    effect on the rate of any of the outcomes, including MI (HR 0.89, 95% CI 0.76, 1.05) and any diabetes-related endpoint (HR 0.98, 95% CI 0.87, 1.09). CONCLUSIONS/INTERPRETATION: In the DCGP study, a smaller proportion of patients who received structured care experienced a first occurrence of MI or any......Abstract AIMS/HYPOTHESIS: The estimation of effect size in clinical trials commonly disregards recurrent outcomes. We investigated the effectiveness of a complex intervention on recurrent outcomes in patients with type 2 diabetes. METHODS: In the Diabetes Care in General Practice (DCGP) randomised...... diabetes-related endpoint. However, for all outcomes, the HR for a second event showed a statistically non-significant tendency to be increased. We estimated a combined HR for all marginal failure times, regardless of whether they were first, second or later events. This showed that the intervention had no...

  6. Analytical assessment of shear rigidity degradation of embedded box-type reinforced concrete structures

    Investigation of the behavior of embedded box-type reinforced concrete (RC) structures for nuclear power stations subjected to lateral earthquake earth pressure, concerning shear rigidity and its reduction, has been conducted analytically in this study. A nonlinear finite element approach based on smeared crack model of RC plate element was utilized. From the parametric study of a real RC duct for accommodating emergency cooling water pipes in nuclear power stations, it was found that lower reduced shear rigidity factor, which was defined as the ratio of reduced and initial shear rigidity, could be attained by arranging lower concrete compressive strength, higher yield strength of reinforcing bar, higher reinforcement ratio and thinner wall thickness of the RC duct. Finally, a formula to predict the reduced shear rigidity factor has been proposed based on the parametric study. (author)

  7. Nanoscale calibration of n-type ZnO staircase structures by scanning capacitance microscopy

    Wang, L.; Laurent, J.; Chauveau, J. M.; Sallet, V.; Jomard, F.; Brémond, G.

    2015-11-01

    Cross-sectional scanning capacitance microscopy (SCM) was performed on n-type ZnO multi-layer structures homoepitaxially grown by molecular beam epitaxy method. Highly contrasted SCM signals were obtained between the ZnO layers with different Ga densities. Through comparison with dopant depth profiles from secondary ion mass spectroscopy measurement, it is demonstrated that SCM is able to distinguish carrier concentrations at all levels of the samples (from 2 × 1017 cm-3 to 3 × 1020 cm-3). The good agreement of the results from the two techniques indicates that SCM can be a useful tool for two dimensional carrier profiling at nanoscale for ZnO nanostructure development. As an example, residual carrier concentration inside the non-intentionally doped buffer layer was estimated to be around 2 × 1016 cm-3 through calibration analysis.

  8. Nanoscale calibration of n-type ZnO staircase structures by scanning capacitance microscopy

    Cross-sectional scanning capacitance microscopy (SCM) was performed on n-type ZnO multi-layer structures homoepitaxially grown by molecular beam epitaxy method. Highly contrasted SCM signals were obtained between the ZnO layers with different Ga densities. Through comparison with dopant depth profiles from secondary ion mass spectroscopy measurement, it is demonstrated that SCM is able to distinguish carrier concentrations at all levels of the samples (from 2 × 1017 cm−3 to 3 × 1020 cm−3). The good agreement of the results from the two techniques indicates that SCM can be a useful tool for two dimensional carrier profiling at nanoscale for ZnO nanostructure development. As an example, residual carrier concentration inside the non-intentionally doped buffer layer was estimated to be around 2 × 1016 cm−3 through calibration analysis

  9. Low dimentional magnetic properties of compounds belonging to the CrVO4-type structure

    Compounds with the ABX4 composition exhibit a range of different magnetic properties. In recent years we have concentrated on only those adopting the CrVO4-type structure, where we have a magnetic atom occupying the A position and a diamagnetic only atom within the B position. The A atom is housed within a distorted octahedral environment, the AO6 units are edge sharing and form buckled ribbon chains along the c-axis. The B atoms are contained within tetrahedral Oxygen environments which bridge the ribbon chains. We are present first results on the magnetic properties of some selected of this series which show, multiferroic behavior, spin-Peierls transitions and conventional long-range magnetic ordering.

  10. Linear algebraic analyses of structures with one predominant type of anomalous scatterer

    Further studies have been made of the information content of the exact linear equations for analyzing anomalous dispersion data in one-wavelength experiments. The case of interest concerns structures containing atoms that essentially do not scatter anomalously and one type of anomalously scattering atoms. For this case, there are three alternative ways of writing the equations. The alternative sets of equations and the transformations for transforming one set into the other are given explicitly. Comparison calculations were made with different sets of equations. Isomorphous replacement information is readily introduced into the calculations and the advantage of doing so is clearly illustrated by the results. Another aspect of the potential of the exact linear algebraic theory is its application to multiple-wavelength experiments. Successful applications of the latter have been made by several collaborative groups of investigators. (orig.)

  11. Measuring Mangrove Type, Structure And Carbon Storage With UAVSAR And ALOS/PALSAR Data

    Fatoyinbo, T. E.; Cornforth, W.; Pinto, N.; Simard, M.; Pettorelli, N.

    2011-12-01

    Mangrove forests provide a great number of ecosystem services ranging from shoreline protection (e.g. against erosion, tsunamis and storms), nutrient cycling, fisheries production, building materials and habitat. Mangrove forests have been shown to store very large amounts of Carbon, both above and belowground, with storage capacities even greater than tropical rainforests. But as a result of their location and economic value, they are among the most rapidly changing landscapes in the World. Mangrove extent is limited 1) in total extent to tidally influenced coastal areas and 2) to tropical and subtropical regions. This can lead to difficulties mapping mangrove type (such as degraded vs non degraded, scrub vs tall, dense vs sparse) because of cloud cover and limited access to high-resolution optical data. To accurately quantify the effect of land use and climate change on tropical wetland ecosystems, we must develop effective mapping methodologies that take into account not only extent, but also the structure and health of the ecosystem. This must be done by including Synthetic Aperture Radar (SAR) data. In this research, we used L-band Synthetic Aperture Radar data from the ALOS/PALSAR and UAVSAR instruments over selected sites in the Americas (Sierpe, Costa Rica and Everglades, Florida)and Asia (Sundarbans). In particular, we used the SAR data in combination with other remotely sensed data and field data to 1) map mangrove extent 2) determine mangrove type, health and adjascent land use, and 3) estimate aboveground biomass and carbon storage for entire mangrove systems. We used different classification methodologies such as polarimetric decomposition, unsupervised classification and image segmentation to map mangrove type. Because of the high resolution of the radar data, and its ability to interact with forest volume, we are able to identify mangrove zones and differentiate between mangroves and other forests/land uses. We also integrated InSAR data (SRTM), spaceborne Lidar (GLAS) and field data, in combination with the SAR data to derive aboveground biomass and carbon storage in mangroves. We successfully produced maps of mangrove extent, type, health and carbon storage by using L-band SAR data. Our results show that both UAVSAR and ALOS/PALSAR data alone are effective datasets for mapping mangrove extent, type and other land use. By combining multiple datasets, we were able to determine mangrove biomass without an upper estimation limit and with low error.

  12. Observations of ion cyclotron harmonic structure in Type 1 to 4 VHF AURORAL ECHOES

    The understanding of E region plasma instabilities is crucial for the interpretation of the enormous stream of data from large ongoing projcets like STARE and SABRE in Europe, and BARS in Canada, in which measurements of radar scatter from E region plasma waves are used to infer the electric fields, hydromagnetic waves, and field-aligned currents in the E region. Auroral echoes measured by 50 MHz CW Doppler radars strongly indicate that the electrostatic ion cyclotron (EIC) mechanism may be more important in auroral irregularity formation than was previously suspected. Doppler spectra taken over 64 ms intervals are highly structured, showing as many as seven or eight discrete frequency components whose frequency separation is often approximately the cyclotron frequency of one of the principal ions in the E region. In this note, we show that when examples of each of the four standard spectral types (1 to 4), whose classification is based upon time-averaging over several seconds, are examined with the finer time resolution of 64 ms (i.e., a resolution of the same order as the lifetime of the individual plasma irregularities), all four types appear to be composites of many harmonically structured bursts as described above. Since the spectral components in individual bursts may occur at frequencies that are not exact multiples of the ion gyrofrequency, time averaging over many bursts usually smears out the harmonic content, resulting in broader spectral peaks. The resulting smoothed spectra then appear to be caused by instabilities other than the EIC instability. copyright American Geophysical Union 1988

  13. Passivation of W-structured type-II superlattice long-wave infrared photodiodes

    Aifer, E. H.; Warner, J. H.; Stine, R. R.; Vurgaftman, I.; Canedy, C. L.; Jackson, E. M.; Tischler, J. G.; Meyer, J. R.; Petrovykh, D. Y.; Whitman, L. J.

    2007-04-01

    A critical step in developing type-II superlattice (T2SL) based LWIR focal plane array (FPA) technology is to achieve high performance levels in FPA pixel-sized devices having 20-40 μm pitch. At this scale, device performance tends to be limited by surface effects along mesa sidewalls which are etched to provide pixel isolation. While control of surface leakage has been achieved for MWIR T2SLs, as evidenced by the availability of commercially produced FPAs, the same cannot be said for LWIR T2SLs. Several groups have approached this problem as strictly a matter of surface treatment, including cleaning, chemical treatment, and dielectric coating or epitaxial overgrowth, but with limited success. Here we describe an approach based on shallow-etch mesa isolation (SEMI), which takes advantage of bandgap grading to isolate devices without exposing narrow-gap LWIR regions on diode mesas sidewalls. The SEMI process consists of defining mesa diodes with a shallow etch that passes only 20-100 nm past the junction of a graded-gap "W"-structured type-II superlattice p-i-n structure, where the bandgap remains large (>200 meV). A second, deeper etch is then used to define a trench along the chip border for access to the p-contact. As a result, SEMI diodes have only MWIR layers exposed along sidewalls, while the LWIR regions remain buried and unexposed. We also discuss an investigation of surface passivation of GaSb with sulfur using thioacetamide.

  14. Quantification of age-related changes in the structure model type and trabecular thickness of human tibial cancellous

    Ding, Ming; Hvid, I

    2000-01-01

    traditionally been measured using model-based histomorphometric methods on two-dimensional (2-D) sections. However, no quantitative study has been published based on three-dimensional (3-D) methods on the age-related changes in structure model type and trabecular thickness for human peripheral (tibial......) cancellous bone. In this study, 160 human proximal tibial cancellous bone specimens from 40 normal donors, aged 16 to 85 years, were collected. These specimens were micro-computed tomography (micro-CT) scanned, then the micro-CT images were segmented using optimal thresholds. From accurate 3-D data sets......, structure model type and trabecular thickness were quantified by means of novel 3-D methods. Structure model type was assessed by calculating the structure model index (SMI). The SMI was quantified based on a differential analysis of the triangulated bone surface of a structure. This technique allows...

  15. Direct metal micropatterning on needle-type structures towards bioimpedance and chemical sensing applications

    Direct metal patterning methods, such as screen printing, inkjet printing and gravure/flexography printing, are widely used to form electrodes or interconnections for printed electronic devices due to their inexpensive, simple and rapid fabrication as compared to vacuum-based conventional metallization processes. Here, we present direct metal patterning by modified screen printing on the curved surface of needle-type rod structures (i.e. rods with radius of ρ < 1 mm). We achieved various microscale patterns such as straight lines, zigzag lines, wavy lines and alphabetic words with a minimum width of 70 µm on the surface of the rod. Also, four pairs of line patterns were printed on the single rod for electrical interconnection. Printed patterns on the surface of the rod were used as electrodes for the control of a light emission diode (LED) as well as the real-time electrochemical impedance spectroscopy of electrolyte solutions and solid objects by the rod insertion. Furthermore, needles with multiple pairs of microelectrodes were used to measure the electrical impedance of biological samples such as fat and muscle tissues of porcine meat. In addition, a needle-type probe sensor with gas sensing capability was demonstrated by using a needle with printed Ag electrodes and Pd thin films. (paper)

  16. Radiation damage structure in irradiated and annealed 440 WWER-Type reactor pressure vessel steels

    A review of irradiation damages in WWER-type RPV steels based on conventional Transmission Electron Microscopy investigations in a power reactor and a research reactor, is presented; the samples consist in Cr-Mo-V ferritic steel (15Kh2MFA type). The visible part of radiation-induced defects consists of very fine vanadium carbide precipitates, small dislocation loops and black dots (presumably corresponding to clusters and particle embryos formed from vacancies and solute-atoms (vanadium, copper, phosphorus) and carbon associated with vanadium. Radiation-induced defects are concentrated at dislocation substructure during irradiation in a power reactor, revealing the role of radiation-enhanced diffusion in damage structure forming process. Contrarily, the distribution of defects resulting from annealing of specimens irradiated in the research reactor is pre-determined by an homogenous distribution of radiation-induced defects prior to annealing. Increasing the number of re-irradiation and annealing cycles, the amount of dislocation loops among all defects seems to be growing. Simultaneously, the dislocation substructure recovers considerably. (authors). 14 refs., 11 figs., 3 tabs

  17. Efficiency of different forest types in carbon storage depends on their internal structure

    Iuliana F. Gheorghe

    2011-04-01

    Full Text Available Forest vegetation is a key factor in the maintenance of global carbon cycle balance under the present climate change conditions. Forest ecosystems are both buffers against extreme climatic events accompanying climate change and carbon sinks diminishing the environmental impact of anthropogenic greenhouse gas emissions. We investigated the influence of stand structure and site characteristics on the productivity and carbon storage capacity of temperate forest types. Predictors of species productivity were parameters such as stand density, age, height, average diameter and wood density. Morus alba (L. was more productive than average both in terms of annual volume increment and annual biomass gain, while Quercus sessiliflora (Matt. Lieb. and Quercus frainetto (Ten. were significantly less productive than average. Differences in stand productivity were explained by stand density, age, height, altitude, type of regeneration and species composition. Statistically significant differences were measured between the productivity of stands dominated by different woody species, with low productive stands dominated by slow growing species with high wood density like Quercus or Fagus, and highly productive stands rich in fast growing species with low wood density like Populus or Salix. Stands with different plant communities in the underlying herbaceous layer also tended to have different levels of productivity.

  18. Structural myocardial involvement in adult patients with type 1 myotonic dystrophy

    Upinder K. Dhand

    2013-03-01

    Full Text Available Myotonic dystrophy type 1 (DM1 is the commonest muscular dystrophy in adults, affecting multiple organs in addition to skeletal muscles. Cardiac conduction system abnormalities are well recognized as an important component of DM1 phenotype; however, primary structural myocardial abnormalities, which may predispose these patients to congestive heart failure, are not as well characterized. We reviewed the retrospective analysis of the clinical and echocardiographic findings in adult patients with DM1. Among 27 patients (16 male; age 19-61 years with DM1, the echocardiogram (ECHO was abnormal in 10 (37% including one of 6 patients (16% with congenital myotonic dystrophy. Reduced left ventricular ejection fraction (LVEF ≤50% was noted in 5, diastolic dysfunction in 4, left atrial dilatation in 3, left ventricular hypertrophy in 2, apical hypokinesia in 1 and mitral valve prolapse in 3 patients. One patient had paradoxical septal movement in the setting of left bundle branch block. Echocardiographic abnormalities significantly correlated with older age; however, patients with systolic dysfunction on echocardiogram ranged in age from 27 to 52 years including 2 patients aged 27 and 34 years. We can conclude that echocardiographic abnormalities are frequent in adult patients with DM1. The incidence is similar in the classical and congenital type of DM1. Overall, echocardiographic abnormalities in DM1 correlate with increasing age; however, reduced LVEF is observed even at young age. Cardiac assessment and monitoring in adult patients with DM1 should include evaluation for primary myocardial involvement.

  19. Structure and stability of monazite- and zircon-type LaVO4 under hydrostatic pressure

    Cheng, Xuerui; Guo, Dongjie; Feng, Shiquan; Yang, Kun; Wang, Yongqiang; Ren, Yufen; Song, Yang

    2015-11-01

    Pure monazite (m)- and zircon (t)-type LaVO4 and LaVO4:Eu3+ were successfully synthesized by a hydrothermal method. The high pressure behavior of m- and t-LaVO4 nanoparticles has been investigated using Raman scattering techniques at room temperature. Raman measurements reveal a slight change for m-LaVO4 at 11.2 GPa because of an isostructural phase transition. However, striking changes in Raman spectra indicate a pressure-induced irreversible phase transition from the zircon to monazite structure for t-LaVO4 at around 5.9 GPa. The evolution of the luminescence spectra of t-LaVO4:Eu3+ has also been studied during the pressure-induced phase transition. It is observed that pressure has a great influence on the fluorescence intensity and the energy levels, which allows a more in-depth understanding of the nature of the pressure-induced phase transition for t-LaVO4. This result further confirms the conclusion that zircon-type RVO4 compounds with larger rare-earth cations will experience zircon to monazite phase transition.

  20. Cyclodextrins in pharmaceutical formulations I: structure and physicochemical properties, formation of complexes, and types of complex.

    Jambhekar, Sunil S; Breen, Philip

    2016-02-01

    Cyclodextrins are cyclic oligosaccharides that have been recognized as pharmaceutical adjuvants for the past 20 years. The molecular structure of these glucose derivatives, which approximates a truncated cone, bucket, or torus, generates a hydrophilic exterior surface and a nonpolar interior cavity. Cyclodextrins can interact with appropriately sized drug molecules to yield an inclusion complex. These noncovalent inclusion complexes offer a variety of advantages over the noncomplexed form of a drug. Cyclodextrins are primarily used to enhance the aqueous solubility, physical chemical stability, and bioavailability of drugs. Their other applications include preventing drug-drug interactions, converting liquid drugs into microcrystalline powders, minimizing gastrointestinal and ocular irritation, and reducing or eliminating unpleasant taste and smell. Here, we discuss the physical chemical properties of various cyclodextrins, including the effects of substitutions on these properties. Additionally, we report on the regulatory status of their use, commercial products containing cyclodextrins, toxicological considerations, and the forces involved in complex formation. We also highlight the types of complex formed and discuss the methods used to determine the types of complex present. PMID:26686054

  1. Ce3+ incorporated structural and magnetic properties of M type barium hexaferrites

    M type barium hexaferrites BaCexFe12−xO19 (0≤x≤0.3) (BCFO) were synthesized by the sol–gel auto combination method. Optimum annealing temperature of hexagonal phase was determined by using the TGA analysis. The annealing temperature form the TGA is 1000 °C samples annealed 1000 °C for 5 h to produce M type hexaferrites. X-ray diffraction data run to full Prof Program (Winploter 2010) pattern indicate that samples are single phase hexagonal structure with space group P63/mmc. Lattice parameter ‘a’ and ‘c’ increase with increase in Ce content x. Results of field emission scanning electron microscope show that the grains are regular hexagonal platelets with sizes from 0.3 to 1.4 μm. It is observed that from M–H curve value of the saturation magnetization and coercivity decreases with increasing x. Curie temperature from magnetization with temperature plot is found to decrease with Ce3+ substitution x due to decreases in magnetic interaction. - Highlights: • Ce3+ substituted Ba hexaferrites. • Increased coercivity with Ce3+ substitution. • Decrease in saturation magnetization and Curie temperature

  2. The Electronic Structure of CdSe/CdS Core/Shell Seeded Nanorods: Type-I or Quasi-Type-II?

    Eshet, Hagai; Rabani, Eran

    2013-01-01

    The electronic structure of CdSe/CdS core/shell seeded nanorods of experimentally relevant size is studied using a combination of molecular dynamics and semiempirical pseudopotential techniques, with the aim to address the transition from type-I to a quasi-type-II band alignment. The hole is found to be localized in the core region regardless of its size. When electron-hole interactions are neglected, we observe little overlap of electron density with the core region, consistent with type-II behavior. When electron-hole interactions are taken into account, we find that the overlap of the electron density with the core decreases with decreasing size, consistent with a transition to quasi-type II. We attribute this transition to an interplay of electron-hole interactions and volume effects, and not to band alignment. Our results provide insight to both scanning tunneling and optical measurements.

  3. Analysis of the population structure of Anaplasma phagocytophilum using multilocus sequence typing.

    Huhn, Christian; Winter, Christina; Wolfsperger, Timo; Wüppenhorst, Nicole; Strašek Smrdel, Katja; Skuballa, Jasmin; Pfäffle, Miriam; Petney, Trevor; Silaghi, Cornelia; Dyachenko, Viktor; Pantchev, Nikola; Straubinger, Reinhard K; Schaarschmidt-Kiener, Daniel; Ganter, Martin; Aardema, Matthew L; von Loewenich, Friederike D

    2014-01-01

    Anaplasma phagocytophilum is a Gram-negative obligate intracellular bacterium that replicates in neutrophils. It is transmitted via tick-bite and causes febrile disease in humans and animals. Human granulocytic anaplasmosis is regarded as an emerging infectious disease in North America, Europe and Asia. However, although increasingly detected, it is still rare in Europe. Clinically apparent A. phagocytophilum infections in animals are mainly found in horses, dogs, cats, sheep and cattle. Evidence from cross-infection experiments that A. phagocytophilum isolates of distinct host origin are not uniformly infectious for heterologous hosts has led to several approaches of molecular strain characterization. Unfortunately, the results of these studies are not always easily comparable, because different gene regions and fragment lengths were investigated. Multilocus sequence typing is a widely accepted method for molecular characterization of bacteria. We here provide for the first time a universal typing method that is easily transferable between different laboratories. We validated our approach on an unprecedented large data set of almost 400 A. phagocytophilum strains from humans and animals mostly from Europe. The typability was 74% (284/383). One major clonal complex containing 177 strains was detected. However, 54% (49/90) of the sequence types were not part of a clonal complex indicating that the population structure of A. phagocytophilum is probably semiclonal. All strains from humans, dogs and horses from Europe belonged to the same clonal complex. As canine and equine granulocytic anaplasmosis occurs frequently in Europe, human granulocytic anaplasmosis is likely to be underdiagnosed in Europe. Further, wild boars and hedgehogs may serve as reservoir hosts of the disease in humans and domestic animals in Europe, because their strains belonged to the same clonal complex. In contrast, as they were only distantly related, roe deer, voles and shrews are unlikely to harbor A. phagocytophilum strains infectious for humans, domestic or farm animals. PMID:24699849

  4. Structural, dielectric and magnetic properties of Cd/Pb doped W-type hexaferrites

    Hooda, Ashima; Sanghi, Sujata, E-mail: sutkash@yahoo.com; Agarwal, Ashish; Dahiya, Reetu

    2014-01-15

    W-type hexaferrites having compositions Ba(Zn{sub 0.5}Cd{sub 0.5}){sub 2}Fe{sub 16}O{sub 27} (BZCFO) and Ba(Zn{sub 0.5}Pb{sub 0.5}){sub 2}Fe{sub 16}O{sub 27} (BZPFO) were synthesized by solid state reaction method at high annealing temperature. Their dielectric and magnetic properties as a function of temperature and frequency have been studied. X-ray analysis confirms the presence of W-type hexaferrite phase structure. SEM analysis presented heterogeneous hexagonal shape and sizes of grains. Analysis of Nyquist plots of prepared samples revealed the contribution of electrically active regions corresponding to grains and grain boundaries. The reciprocal temperature dependence of dc electrical resistivity (?) satisfies the Arrhenius relation which depicted the semi-conducting behavior of the samples. The variation of dielectric constant (??) and dielectric loss (tan ?) with temperature (323 K573 K) and frequency (1 kHz5 MHz) are studied. Analysis of the experimental conductivity data and s parameter shows that correlated barrier hopping (CBH) mechanism is the most probable mechanism of conduction for BZCFO sample; whereas for BZPFO hexaferrite, both correlated barrier hopping (CBH) and quantum mechanical tunneling (QMT) model are applicable for conduction. The BZCFO sample has higher value of saturation magnetization and lower coercivity than BZPFO sample due to the preference of Cd{sup 2+} for tetrahedral sites and decrease in number of spin-down magnetic ions. - Highlights: W type Ba(Zn{sub 0.5}Cd{sub 0.5}){sub 2}Fe{sub 16}O{sub 27} and Ba(Zn{sub 0.5}Pb{sub 0.5}){sub 2}Fe{sub 16}O{sub 27} hexaferrites were prepared. BZPFO has more resistivity and low values of ?{sub a.c.}, ?? and tan ? than BZCFO. BZCFO has higher saturation magnetization and lower coercivity than BZPFO.

  5. The structure of Ksub(1.33)Mn8O16 and cation ordering in hollandite-type structures

    Crystal data: Msub(r)=747.5, tetragonal, I4/m, a=9.866(3), c=2.872(1) A, V=279.6(2) A3, Z=8(Ksub(0.167)MnO2), Dsub(x)=4.442 g cm-3, lambda(Ag K?, graphite monochromator)=0.56005 A, ?=49.9 cm-1, F(000)=353.5, T=295 K, final R=1.9% for 436 unique reflections. In this mixed-valence compound Ksub(x)Mn4+sub(x8)Mnsub(x)3+O16(x=1.33) the channel cation position (K+) is not at 001/2 but at 00z with z=0.375. It is shown that the symmetry of hollandite-type structures (Asub(x)B8O16) is determined by the relative sizes of the framework (B) and the channel (A) cations. Single-crystal rotation photographs around c show extra diffuse levels between reciprocal-lattice planes perpendicular to c. These extra levels, attributed to channel-cation ordering, have spacings which indicate that, in a given channel, the order involves three unit cells in the c direction. The presence of vacancies in the channels allows a relaxation of the K+ cations and a minimization of the K-K electrostatic repulsion via a displacement of the K+ cations from the centers of their square-prismatic channel sites toward the neighboring vacancies. It seems likely that either diffuse or superstructure reflections should occur in most Asub(x)B8O16 hollandite-type compounds studied so far. In the former case long-range ordering occurs among the A cations and vacancies along a given channel without a correlation between adjacent channels, as in Ksub(1.33)Mn9O16 where the K ordering is one-dimensional. In the latter case the ordering is accompanied by a strong correlation between channels leading to a three-dimensional ordering. (orig.)

  6. On the modular structure of the genus-one Type II superstring low energy expansion

    D'Hoker, Eric; Vanhove, Pierre

    2015-01-01

    The analytic contribution to the low energy expansion of Type II string amplitudes at genus-one is a power series in space-time derivatives with coefficients that are determined by integrals of modular functions over the complex structure modulus of the world-sheet torus. These modular functions are associated with world-sheet vacuum Feynman diagrams and given by multiple sums over the discrete momenta on the torus. In this paper we exhibit exact differential and algebraic relations for a certain infinite class of such modular functions by showing that they satisfy Laplace eigenvalue equations with inhomogeneous terms that are polynomial in non-holomorphic Eisenstein series. Furthermore, we argue that the set of modular functions that contribute to the coefficients of interactions up to order D**10 R*4 are linear sums of functions in this class and quadratic polynomials in Eisenstein series and odd Riemann zeta values. Integration over the complex structure results in coefficients of the low energy expansion ...

  7. On the modular structure of the genus-one Type II superstring low energy expansion

    D'Hoker, Eric; Green, Michael B.; Vanhove, Pierre

    2015-08-01

    The analytic contribution to the low energy expansion of Type II string amplitudes at genus-one is a power series in space-time derivatives with coefficients that are determined by integrals of modular functions over the complex structure modulus of the world-sheet torus. These modular functions are associated with world-sheet vacuum Feynman diagrams and given by multiple sums over the discrete momenta on the torus. In this paper we exhibit exact differential and algebraic relations for a certain infinite class of such modular functions by showing that they satisfy Laplace eigenvalue equations with inhomogeneous terms that are polynomial in non-holomorphic Eisenstein series. Furthermore, we argue that the set of modular functions that contribute to the coefficients of interactions up to order are linear sums of functions in this class and quadratic polynomials in Eisenstein series and odd Riemann zeta values. Integration over the complex structure results in coefficients of the low energy expansion that are rational numbers multiplying monomials in odd Riemann zeta values.

  8. A COMPARISON OF TWO THERMAL INSULATION AND STRUCTURAL MATERIALS FOR USE IN TYPE B PACKAGINGS

    Blanton, P.; Eberl, K.

    2010-07-16

    This paper presents the summary of design features and test results of two Type B Shipping Package prototype configurations comprising different insulating materials developed by the Savannah River National Laboratory (SRNL) for the Department of Energy. The materials evaluated, a closed-cell polyurethane foam and a vacuformed ceramic fiber material, were selected to provide adequate structural protection to the package containment vessel during Normal Conditions of Transport (NCT) and Hypothetical Accident Condition (HAC) events and to provide thermal protection during the HAC fire. Polyurethane foam has been used in shipping package designs for many years because of the stiffness it provides to the structure and because of the thermal protection it provides during fire scenarios. This comparison describes how ceramic fiber material offers an alternative to the polyurethane foam in a specific overpack design. Because of the high operating temperature ({approx}2,300 F) of the ceramic material, it allows for contents with higher heat loads to be shipped than is possible with polyurethane foam. Methods of manufacturing and design considerations using the two materials will be addressed.

  9. Cloud cover typing from environmental satellite imagery. Discriminating cloud structure with Fast Fourier Transforms (FFT)

    Logan, T. L.; Huning, J. R.; Glackin, D. L.

    1983-01-01

    The use of two dimensional Fast Fourier Transforms (FFTs) subjected to pattern recognition technology for the identification and classification of low altitude stratus cloud structure from Geostationary Operational Environmental Satellite (GOES) imagery was examined. The development of a scene independent pattern recognition methodology, unconstrained by conventional cloud morphological classifications was emphasized. A technique for extracting cloud shape, direction, and size attributes from GOES visual imagery was developed. These attributes were combined with two statistical attributes (cloud mean brightness, cloud standard deviation), and interrogated using unsupervised clustering amd maximum likelihood classification techniques. Results indicate that: (1) the key cloud discrimination attributes are mean brightness, direction, shape, and minimum size; (2) cloud structure can be differentiated at given pixel scales; (3) cloud type may be identifiable at coarser scales; (4) there are positive indications of scene independence which would permit development of a cloud signature bank; (5) edge enhancement of GOES imagery does not appreciably improve cloud classification over the use of raw data; and (6) the GOES imagery must be apodized before generation of FFTs.

  10. Numerical model for the analysis of unbounded prestressed structures using the hybrid type finite element method

    Unbounded prestressed concrete has a growing importance all over the world and may be an useful technique for the structures involved in the construction of nuclear facilities. The absence of bonding means no strain compatibility so that equations developed for reinforced concrete are no longer valid. Practical estimates about the ultimate stress in the unbounded tendons may be obtained with empirical or numerical methods only. In order to contribute to the understanding on the behaviour of unbounded prestressed concrete members, a numerical model has been developed using a hybrid type finite element formulation for planar frame structures. Instead of short elements, as in the conventional finite element formulation, long elements may be used, improving computational efficiency. A further advantage is that the curvature variation within the element is obtained with higher accuracy if compared to the traditional formulation. This feature is important for unbounded tendons since its stresses depend on the whole member deformation. Second order effects in the planar frame are considered with either Updated or Partially Updated Lagrangian approaches. Instantaneous and time dependent behaviour as well as cyclic loads are considered too. Comparison with experimental results for prestressed concrete beams shows the adequacy of the proposed model. (authors)

  11. Structural insight into negative DNA supercoiling by DNA gyrase, a bacterial type 2A DNA topoisomerase

    Papillon, Julie; Mntret, Jean-Franois; Batisse, Claire; Hlye, Reynald; Schultz, Patrick; Potier, Nolle; Lamour, Valrie

    2013-01-01

    Type 2A DNA topoisomerases (Topo2A) remodel DNA topology during replication, transcription and chromosome segregation. These multisubunit enzymes catalyze the transport of a double-stranded DNA through a transient break formed in another duplex. The bacterial DNA gyrase, a target for broad-spectrum antibiotics, is the sole Topo2A enzyme able to introduce negative supercoils. We reveal here for the first time the architecture of the full-length Thermus thermophilus DNA gyrase alone and in a cleavage complex with a 155 bp DNA duplex in the presence of the antibiotic ciprofloxacin, using cryo-electron microscopy. The structural organization of the subunits of the full-length DNA gyrase points to a central role of the ATPase domain acting like a crossover trap that may help to sequester the DNA positive crossover before strand passage. Our structural data unveil how DNA is asymmetrically wrapped around the gyrase-specific C-terminal ?-pinwheel domains and guided to introduce negative supercoils through cooperativity between the ATPase and ?-pinwheel domains. The overall conformation of the drug-induced DNA bindingcleavage complex also suggests that ciprofloxacin traps a DNA pre-transport conformation. PMID:23804759

  12. Electrical and structural properties of p -type nanocrystalline silicon grown by LEPECVD for photovoltaic applications

    Micard, Gabriel; Hahn, Giso; Terheiden, Barbara [Department of Physics, Faculty of Sciences, University of Konstanz (Germany); Chrastina, Daniel; Isella, Giovanni; Moiseev, Tamara [L-NESS, Dipartimento di Fisica del Politecnico di Milano, Polo Regionale di Como (Italy); Cavalcoli, Daniela; Cavallini, Anna [Department of Physics, University of Bologna (Italy); Binetti, Simona; Acciarri, Maurizio; Le Donne, Alessia [Dipartimento di Scienza dei Materiali, Universita di Milano-Bicocca, Milano (Italy); Texier, Michael [Institut Materiaux, Microelectronique, Nanosciences de Provence (IM2NP UMR 6242) Fac. Sciences et Techniques de Saint Jerome, Marseille (France); Pichaud, Bernard [Institut Materiaux, Microelectronique, Nanosciences de Provence (IM2NP UMR 6242) Fac. Sciences et Techniques de Saint Jerome, Marseille (France)

    2010-04-15

    p-doped hydrogenated nanocrystalline silicon (p-nc-Si:H) is one of the most critical layers in thin film silicon solar cells. LEPECVD is a new technique for the growth of nc-Si at high growth rate without compromising the layer quality, using a dense but low energy plasma. Thin p-nc-Si:H layers are grown on glass and ZnO:Al coated glass and their structural and electrical properties are investigated as a function of the silane dilution (d) and of the doping ratio (DR). The influence of the substrate on the structural properties is investigated and discussed. The incubation layer is clearly observed on both substrate types and its thickness is estimated. LEPECVD distinguishes itself from other high growth rate methods by a very low impurity distribution coefficient to obtain a comparable conductivity and boron density. The conduction path is shown to be dependent on the density of boron in the layer while a significant decrease of conductivity at high DR is not observed in the studied range (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. The Russian oil industry re-structuration: towards the emergence of western type enterprises?

    Locatelli, C

    1999-01-01

    The Russian oil industry has undergone fundamental changes since the collapse of the Soviet Empire and its bureaucratic administrative structure, dominated by its various Branch Ministries. The monopoly in the Soviet oil industry has now been replaced by a number of ''oil companies'', some of which are very powerful, the best known of them being Lukoil. These ''joint stock companies'' are the product of a reform aimed essentially at implanting, out of all the numerous organisational arrangements developed in the West, the model of the vertically integrated private firm. Beyond the legal reforms in the Russian oil industry sector, however, the nature of the organisational model that has actually emerged in Russia begs several questions. Many entities, which are complex and highly diversified, are involved in this industry. There are, of course, the many private structures in which the banks sometimes carry a considerable amount of weight. There are also some vertically integrated organisations, but the degree of integration is variable and their method of centralization is based on a specific form of economic logic. It should not be considered, however, that these actors are similar to capitalist-type private enterprises, whose behaviour is regulated by the demands of international competition. Reform of property rights has not been sufficient to create true private enterprise in Russia. (author)

  14. Structure of the myotonic dystrophy type 2 RNA and designed small molecules that reduce toxicity.

    Childs-Disney, Jessica L; Yildirim, Ilyas; Park, HaJeung; Lohman, Jeremy R; Guan, Lirui; Tran, Tuan; Sarkar, Partha; Schatz, George C; Disney, Matthew D

    2014-02-21

    Myotonic dystrophy type 2 (DM2) is an incurable neuromuscular disorder caused by a r(CCUG) expansion (r(CCUG)(exp)) that folds into an extended hairpin with periodically repeating 2×2 nucleotide internal loops (5'CCUG/3'GUCC). We designed multivalent compounds that improve DM2-associated defects using information about RNA-small molecule interactions. We also report the first crystal structure of r(CCUG) repeats refined to 2.35 Å. Structural analysis of the three 5'CCUG/3'GUCC repeat internal loops (L) reveals that the CU pairs in L1 are each stabilized by one hydrogen bond and a water-mediated hydrogen bond, while CU pairs in L2 and L3 are stabilized by two hydrogen bonds. Molecular dynamics (MD) simulations reveal that the CU pairs are dynamic and stabilized by Na(+) and water molecules. MD simulations of the binding of the small molecule to r(CCUG) repeats reveal that the lowest free energy binding mode occurs via the major groove, in which one C residue is unstacked and the cross-strand nucleotides are displaced. Moreover, we modeled the binding of our dimeric compound to two 5'CCUG/3'GUCC motifs, which shows that the scaffold on which the RNA-binding modules are displayed provides an optimal distance to span two adjacent loops. PMID:24341895

  15. Structural characterization of ribosome recruitment and translocation by type IV IRES.

    Murray, Jason; Savva, Christos G; Shin, Byung-Sik; Dever, Thomas E; Ramakrishnan, V; Fernández, Israel S

    2016-01-01

    Viral mRNA sequences with a type IV IRES are able to initiate translation without any host initiation factors. Initial recruitment of the small ribosomal subunit as well as two translocation steps before the first peptidyl transfer are essential for the initiation of translation by these mRNAs. Using electron cryomicroscopy (cryo-EM) we have structurally characterized at high resolution how the Cricket Paralysis Virus Internal Ribosomal Entry Site (CrPV-IRES) binds the small ribosomal subunit (40S) and the translocation intermediate stabilized by elongation factor 2 (eEF2). The CrPV-IRES restricts tvhe otherwise flexible 40S head to a conformation compatible with binding the large ribosomal subunit (60S). Once the 60S is recruited, the binary CrPV-IRES/80S complex oscillates between canonical and rotated states (Fernández et al., 2014; Koh et al., 2014), as seen for pre-translocation complexes with tRNAs. Elongation factor eEF2 with a GTP analog stabilizes the ribosome-IRES complex in a rotated state with an extra ~3 degrees of rotation. Key residues in domain IV of eEF2 interact with pseudoknot I (PKI) of the CrPV-IRES stabilizing it in a conformation reminiscent of a hybrid tRNA state. The structure explains how diphthamide, a eukaryotic and archaeal specific post-translational modification of a histidine residue of eEF2, is involved in translocation. PMID:27159451

  16. The Russian oil industry re-structuration: towards the emergence of western type enterprises?

    The Russian oil industry has undergone fundamental changes since the collapse of the Soviet Empire and its bureaucratic administrative structure, dominated by its various Branch Ministries. The monopoly in the Soviet oil industry has now been replaced by a number of ''oil companies'', some of which are very powerful, the best known of them being Lukoil. These ''joint stock companies'' are the product of a reform aimed essentially at implanting, out of all the numerous organisational arrangements developed in the West, the model of the vertically integrated private firm. Beyond the legal reforms in the Russian oil industry sector, however, the nature of the organisational model that has actually emerged in Russia begs several questions. Many entities, which are complex and highly diversified, are involved in this industry. There are, of course, the many private structures in which the banks sometimes carry a considerable amount of weight. There are also some vertically integrated organisations, but the degree of integration is variable and their method of centralization is based on a specific form of economic logic. It should not be considered, however, that these actors are similar to capitalist-type private enterprises, whose behaviour is regulated by the demands of international competition. Reform of property rights has not been sufficient to create true private enterprise in Russia. (author)

  17. Durability improvement assessment in different high strength bacterial structural concrete grades against different types of acids

    Ramin Andalib; M Zaimi Abd Majid; A Keyvanfar; Amirreza Talaiekhozan; Mohd Warid Hussin; A Shafaghat; Rosli Mohd Zin; Chew Tin Lee; Mohammad Ali Fulazzaky; Hasrul Haidar Ismail

    2014-12-01

    This paper provides an insight into a new biotechnological method based on calcite precipitation for achieving high strength bio-concrete durability. It is very clear that mineral precipitation has the potential to enhance construction material resistance towards degradation procedures. The appropriate microbial cell concentration (30 * 105 cells/ml) was introduced onto different structural concrete grades (40, 45 and 50 MPa) by mixing water. In order to study the durability of structural concrete against aggressive agents, specimens were immersed in different types of acids solution (5% H2SO4 and HCl) to compare their effects on 60th, 90th and 120th day. In general, sulphuric acid and hydrochloric acid are known to be the most aggressive natural threats from industrial waters which can penetrate concrete to transfer the soluble calcium salts away from the cement matrix. The experimental results demonstrated that bio-concrete has less weight and strength losses when compared to the ordinary Portland cement concrete without microorganism. It was also found that maximum compressive strength and weight loss occurred during H2SO4 acid immersion as compared to HCl immersion. The density and uniformity of bio-concrete were examined using ultrasonic pulse velocity (UPV) test. Microstructure chemical analysis was also quantified by energy dispersive spectrometer (EDS) to justify the durability improvement in bacterial concrete. It was observed that less sulphur and chloride were noticed in bacterial concrete against H2SO4 and HCl, respectively in comparison to the ordinary Portland cement concrete due to calcite deposition.

  18. Ion beam irradiation effects in strontium zirconium phosphate with NZP-structure type

    Ceramics with the sodium zirconium phosphate or NZP type structure have potential as nuclear waste form and inert matrix materials. For both applications the material will be subjected to self-radiation damage from α-decay of the incorporated actinides. In this study, ion-beam irradiation using Au- and He-ions has been used to simulate the consequences of α-decay and the effects of irradiation on the structural and macroscopic properties (density and hardness) have been investigated. Irradiation by Au-ions resulted in a significant volume contraction of ∼7%, a reduction in hardness of ∼30% and a loss in long-range order at fluences above 1014 Au-ions/cm2. In contrast, little effect on the material properties was noted for samples irradiated with He-ions up to a fluence of 1017 ions/cm2. Thermal annealing was investigated for the highest fluence Au-ion irradiated sample and significant decomposition was observed

  19. Estimation of seismic building structural types using multi-sensor remote sensing and machine learning techniques

    Geiß, Christian; Aravena Pelizari, Patrick; Marconcini, Mattia; Sengara, Wayan; Edwards, Mark; Lakes, Tobia; Taubenböck, Hannes

    2015-06-01

    Detailed information about seismic building structural types (SBSTs) is crucial for accurate earthquake vulnerability and risk modeling as it reflects the main load-bearing structures of buildings and, thus, the behavior under seismic load. However, for numerous urban areas in earthquake prone regions this information is mostly outdated, unavailable, or simply not existent. To this purpose, we present an effective approach to estimate SBSTs by combining scarce in situ observations, multi-sensor remote sensing data and machine learning techniques. In particular, an approach is introduced, which deploys a sequential procedure comprising five main steps, namely calculation of features from remote sensing data, feature selection, outlier detection, generation of synthetic samples, and supervised classification under consideration of both Support Vector Machines and Random Forests. Experimental results obtained for a representative study area, including large parts of the city of Padang (Indonesia), assess the capabilities of the presented approach and confirm its great potential for a reliable area-wide estimation of SBSTs and an effective earthquake loss modeling based on remote sensing, which should be further explored in future research activities.

  20. Superconductivity in LaBi3 with AuCu3-type structure

    Kinjo, Tatsuya; Kajino, Saori; Nishio, Taichiro; Kawashima, Kenji; Yanagi, Yousuke; Hase, Izumi; Yanagisawa, Takashi; Ishida, Shigeyuki; Kito, Hijiri; Takeshita, Nao; Oka, Kunihiko; Eisaki, Hiroshi; Yoshida, Yoshiyuki; Iyo, Akira

    2016-03-01

    We succeeded in synthesizing a new intermetallic compound with a AuCu3-type structure, LaBi3, by utilizing a high-pressure technique. Reacting Bi and LaBi at 450 °C under a pressure of 3.4 GPa resulted in the crystallization of LaBi3 with an a-axis lattice parameter of 4.99\\+/- 0.02\\mathring{{A}} . Sharp superconducting transitions were observed in both its magnetic susceptibility and electrical resistivity at 7.3-7.4 K. The upper critical field {μ }0{H}{{c}2}(0) and Ginzburg-Landau coherence length ξ 0 were estimated to be 1.70 T and 139 Å, respectively. The superconducting transition temperature T c was found to decrease linearly with increasing applied pressure with a slope of -0.26 K GPa-1. Band structure calculations indicated that this compound has a multiband nature and that its Fermi energy is located exactly at one of the peak density of states.

  1. Structural and phase transformations in the low-temperature annealed amorphous “finemet”-type microwires

    Tcherdyntsev, V.V., E-mail: vvch08@yandex.ru [National University of Science and Technology “MISIS”, Moscow 119049 (Russian Federation); Aleev, A.A. [SSC RF Institute for Theoretical and Experimental Physics, Moscow 117218 (Russian Federation); Churyukanova, M.N.; Kaloshkin, S.D. [National University of Science and Technology “MISIS”, Moscow 119049 (Russian Federation); Medvedeva, E.V. [Institute of Electrophysics, Ural Branch, Russian Academy of Sciences, Yekaterinburg 620016 (Russian Federation); Korchuganova, O.A. [SSC RF Institute for Theoretical and Experimental Physics, Moscow 117218 (Russian Federation); Zhukova, V. [Dpto. de Fns. Mater., UPV/EHU, San Sebastian 20018 (Spain); Zhukov, A.P. [Dpto. de Fns. Mater., UPV/EHU, San Sebastian 20018 (Spain); IKERBASQUE, Basque Foundation for Science, 48011 Bilbao (Spain)

    2014-02-15

    Highlights: • Structure and magnetic properties evolution at heating of amorphous microwires was studied. • Relaxation processes in the amorphous phase correlate with an increase in Curie temperature. • Curie temperature change can not be stabilized by a prolonged exposure at pre-crystallization temperatures. • Tomographic atom probe microscopy supports the formation of α-Fe phase precipitations enriched in Si. -- Abstract: Finemet-type glass-coated microwires with amorphous and nanocrystalline structure have been investigated. The relaxation and crystallization processes at heating of amorphous alloy have been studied by DSC method. We observed that the relaxation processes in the amorphous phase correlate with an increasing of the Curie temperature. Additionally a prolonged exposure of the samples below the crystallization temperatures does not stabilize the Curie temperature change. An investigation by the tomographic atom probe microscopy supports the formation of precipitations, probably α-Fe phase, as a result of low-temperature annealing (400 °C, 5 min). We found that the observed nano-sized areas were enriched in silicon.

  2. Structural and phase transformations in the low-temperature annealed amorphous “finemet”-type microwires

    Highlights: • Structure and magnetic properties evolution at heating of amorphous microwires was studied. • Relaxation processes in the amorphous phase correlate with an increase in Curie temperature. • Curie temperature change can not be stabilized by a prolonged exposure at pre-crystallization temperatures. • Tomographic atom probe microscopy supports the formation of α-Fe phase precipitations enriched in Si. -- Abstract: Finemet-type glass-coated microwires with amorphous and nanocrystalline structure have been investigated. The relaxation and crystallization processes at heating of amorphous alloy have been studied by DSC method. We observed that the relaxation processes in the amorphous phase correlate with an increasing of the Curie temperature. Additionally a prolonged exposure of the samples below the crystallization temperatures does not stabilize the Curie temperature change. An investigation by the tomographic atom probe microscopy supports the formation of precipitations, probably α-Fe phase, as a result of low-temperature annealing (400 °C, 5 min). We found that the observed nano-sized areas were enriched in silicon

  3. Structural and Magnetic Properties of Type-M Barium Ferrite - Thermoplastic Natural Rubber Nano composites

    Structural and magnetic properties of type-M barium ferrite (BaFe12O19) nanoparticles (∼ 20 nm) embedded in non-magnetic thermoplastic natural rubber (TPNR) matrices were investigated. The TPNR matrices were prepared from high density polyethylene (HDPE) and natural rubber (NR) in the weight ratios of 80:20 and 60:40, respectively, with 10 wt % of NR in the form of liquid natural rubber (LNR) which act as a comparabilities. BaFe12O19 - filled nano composites with 2 - 12 wt % BaFe12O19 ferrite were prepared using a melt- blending technique. Magnetic hysteresis was measured using a vibrating sample magnetometer (VSM) in a maximum field of 10 kOe at room temperature (25 degree Celsius). The saturation magnetisation (MS), remanence (MR) and coercivity (Hc) were derived from the hysteresis loops. The results show that the structural and magnetic properties of nano composites depend on both the ferrite content and the composition of the natural rubber or plastic in the nano composites. All the nano composites exhibit an exchange bias-like phenomenon resulting from the exchange coupling of spins at the interface between the core ferrimagnetic region and the disordered surface region of the nanoparticles. (author)

  4. The structure of TeV-bright shell-type supernova remnants

    Yang, Chuyuan; Liu, Siming; Fang, Jun; Li, Hui

    2015-01-01

    Aims: Two-dimensional magnetohydrodynamic (MHD) simulations are used to model the emission properties of TeV-bright shell-type supernova remnants (SNRs) and to explore their nature. Methods: In the leptonic scenario for the TeV emission, the ?-ray emission is produced via inverse Compton scattering of background soft photons by high-energy electrons accelerated by the shocks of the SNRs. In a previous paper, we showed that since the energy densities of the cosmic microwave background radiation and that of the IR/optical background photons are much higher than that of the photons produced by the same high-energy electrons via the synchrotron process, the observed correlation between X-ray and TeV brightness of SNR RX J1713.7-3946 can be readily explained with the assumption that the energy density of relativistic electrons is proportional to that of the magnetic field. The TeV emissivity is therefore proportional to the magnetic field energy density and MHD simulations can be used to model the TeV structure of such remnants directly. Two-dimensional MHD simulations for SNRs are then performed under the assumption that the ambient interstellar medium is turbulent with the magnetic field and density fluctuations, following a Kolmogorov-like power-law spectrum. Results: (1) As expected, these simulations confirm early 1D and 2D modelings of these sources, namely the hydrodynamical evolution of the shock waves and amplification of magnetic field by Rayleigh-Taylor convective flows and by shocks propagating in a turbulent medium; (2) we reproduce rather complex morphological structure for ?-rays, for example, the bright thin rim and significant asymmetry, suggesting intrinsic variations of the source morphology not related to the structure of the progenitor and environment; and (3) the observed radial profile of several remnants are well reproduced with an ambient medium density of 0.1-1 cm-3. An even lower ambient density leads to a sharper drop of the TeV brightness with radius than what is observed near the outer edge of these remnants. Conclusions: In a turbulent background medium, we can reproduce the observed characteristics of several shell-type TeV SNRs with reasonable parameters except for a higher ambient density than that inferred from X-ray observations.

  5. Li-ion diffusion kinetics in LiCoPO{sub 4} thin films deposited on NASICON-type glass ceramic electrolytes by magnetron sputtering

    Xie, J.; Imanishi, N.; Zhang, T.; Hirano, A.; Takeda, Y.; Yamamoto, O. [Department of Chemistry, Faculty of Engineering, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507 (Japan)

    2009-07-15

    LiCoPO{sub 4} thin films were deposited on Li{sub 1+x+y}Al{sub x}Ti{sub 2-x}Si{sub y}P{sub 3-y}O{sub 12} (LATSP) solid electrolyte by radio frequency magnetron sputtering and were characterized by X-ray diffraction and scanning electron microscope. The films show a (1 1 1) preferred orientation upon annealing and are chemically stable with LATSP up to 600 C in air. An all-solid-state Li/PEO{sub 18}-Li(CF{sub 3}SO{sub 2}){sub 2}N/LATSP/LiCoPO{sub 4}/Au cell was fabricated to investigate the electrochemical performance and Li-ion chemical diffusion coefficients, D{sub Li}, of the LiCoPO{sub 4} thin films. The potential dependence of D{sub Li} values of the LiCoPO{sub 4} thin film was investigated by potentiostatic intermittent titration technique and was compared with those of the LiFePO{sub 4} thin film. These results showed that the intercalation mechanism of Li-ion in LiCoPO{sub 4} is different from that in LiFePO{sub 4}. (author)

  6. The influence of dendritic structure stereology on frictional wear of cast steel Cr-Mo-V-Ni-Cu type

    The paper presents quantitative and qualitative influence of stereological structure parameters on abrasive wear of alloy cast steel Cr-Mo-V-Ni-Cu type at temperature of 293 K and 773 K. The dependence between frictional wear and structural parameters - i.e.: interdendritic space; mean linear size, relative volume and dispersion index of the dendrites - has been estimated. (author)

  7. An area-efficient topology for VLSI implementation of Viterbi decoders and other shuffle-exchange type structures

    Sparsø, Jens; Jørgensen, Henrik Nordtorp; Paaske, Erik; Pedersen, Steen; Rübner-Petersen, Torben

    1991-01-01

    A topology for single-chip implementation of computing structures based on shuffle-exchange (SE)-type interconnection networks is presented. The topology is suited for structures with a small number of processing elements (i.e. 32-128) whose area cannot be neglected compared to the area required...

  8. Structures and free energy landscapes of the A53T mutant-type α-synuclein protein and impact of A53T mutation on the structures of the wild-type α-synuclein protein with dynamics.

    Coskuner, Orkid; Wise-Scira, Olivia

    2013-07-17

    The A53T genetic missense mutation of the wild-type α-synuclein (αS) protein was initially identified in Greek and Italian families with familial Parkinson's disease. Detailed understanding of the structures and the changes induced in the wild-type αS structure by the A53T mutation, as well as establishing the direct relationships between the rapid conformational changes and free energy landscapes of these intrinsically disordered fibrillogenic proteins, helps to enhance our fundamental knowledge and to gain insights into the pathogenic mechanism of Parkinson's disease. We employed extensive parallel tempering molecular dynamics simulations along with thermodynamic calculations to determine the secondary and tertiary structural properties as well as the conformational free energy surfaces of the wild-type and A53T mutant-type αS proteins in an aqueous solution medium using both implicit and explicit water models. The confined aqueous volume effect in the simulations of disordered proteins using an explicit model for water is addressed for a model disordered protein. We also assessed the stabilities of the residual secondary structure component interconversions in αS based on free energy calculations at the atomic level with dynamics using our recently developed theoretical strategy. To the best of our knowledge, this study presents the first detailed comparison of the structural properties linked directly to the conformational free energy landscapes of the monomeric wild-type and A53T mutant-type α-synuclein proteins in an aqueous solution environment. Results demonstrate that the β-sheet structure is significantly more altered than the helical structure upon A53T mutation of the monomeric wild-type αS protein in aqueous solution. The β-sheet content close to the mutation site in the N-terminal region is more abundant while the non-amyloid-β component (NAC) and C-terminal regions show a decrease in β-sheet abundance upon A53T mutation. Obtained results utilizing our new theoretical strategy show that the residual secondary structure conversion stabilities resulting in α-helix formation are not significantly affected by the mutation. Interestingly, the residual secondary structure conversion stabilities show that secondary structure conversions resulting in β-sheet formation are influenced by the A53T mutation and the most stable residual transition yielding β-sheet occurs directly from the coil structure. Long-range interactions detected between the NAC region and the N- or C-terminal regions of the wild-type αS disappear upon A53T mutation. The A53T mutant-type αS structures are thermodynamically more stable than those of the wild-type αS protein structures in aqueous solution. Overall, the higher propensity of the A53T mutant-type αS protein to aggregate in comparison to the wild-type αS protein is related to the increased β-sheet formation and lack of strong intramolecular long-range interactions in the N-terminal region in comparison to its wild-type form. The specific residual secondary structure component stabilities reported herein provide information helpful for designing and synthesizing small organic molecules that can block the β-sheet forming residues, which are reactive toward aggregation. PMID:23607785

  9. Monazite-type ceramics for conditioning of minor actinides. Structural characterization and properties

    The minor actinides (MA) neptunium, americium, and curium are mainly responsible for the long-term radiotoxicity of the High Active Waste (HAW) generated during the nuclear power operation. If these long-lived radionuclides are removed from the HAW by partitioning and converted by neutron fission (transmutation) into shorter-lived or stable elements, the remaining waste loses most of its long-term radiotoxicity. Thus, partitioning and transmutation (P and T) are considered as attractive options for reducing the burden on geological disposals. As an alternative, these separated MA can also be conditioned (P and C strategy) in specifically adapted ceramics to ensure their safe final disposal over long periods. At the moment, spent fuel elements are foreseen either for direct disposal in deep geological repositories or for reprocessing. The highly active liquid waste that is produced during reprocessing is conditioned industrially using a vitrification process before final disposal. Although the widely used borosilicate glasses meet most of the specifications needed, ceramic host matrices appear to be even more suitable in terms of resistance to corrosion. The development of new materials based on tailor-made highly specific ceramics with extremely stable behavior would make it possible to improve the final storage of long-lived high-level radiotoxic waste. In the framework of this PhD research project, monazite-type ceramics were chosen as promising host matrices for the conditioning of trivalent actinides. The focus on the monazite-type ceramics is justified by their properties such as high chemical durability. REPO4 ceramics are named monazite for RE = La - Gd (monoclinic symmetry) and xenotime for RE = Tb - Lu and Y (tetragonal symmetry). The objective of this study is to contribute to the understanding of the alteration behavior of such ceramics under the repository conditions. REPO4 (with RE = La, Eu) is prepared by hydrothermal synthesis at 200 C. Structural and morphological characteristics (using X-ray diffraction (XRD) and scanning electron microscope (SEM)) combined with physical and thermal properties of samples (using thermogravimetry, differential scanning calorimetry (TG-DSC) and dilatometry) are realized in order to study the behavior of monazite-type powder and pellets. The access to short-range-order spectroscopy (time resolved laser fluorescence spectroscopy (TRLFS) and extended X-ray absorption fine structure (EXAFS)) permits to understand the structure of ceramic waste forms at the molecular level. La-monazite matrices being doped with Eu (III) (as a non-radioactive chemical homologue for Am (III)) and Cm (III), TRLFS is used to explore the local structural environment of Eu and Cm within the monazite crystal structure. Eu (III) and Cm (III) are substituted on the La site of LaPO4. The single site of Cm (III) is found in four slightly different environments which is assumed to be due to a difference in the four La sites within a LaPO4 unit cell. Structural parameters of the Eu (III) species were also analyzed by EXAFS. The nearest neighbors of Eu (III) are modeled as 9.5 oxygen atoms (NO1 = 4 at r(EuO1) = 2.37 Aa, NO2 = 4 at r(Eu-O2) = 2.53 Aa, and NO3 = 1.5 at r(Eu-O3) = 2.83 Aa). An essential parameter that describes the stability of the host phases is their dissolution rate obtained under conditions of relevance for final repositories. In this context, a set-up is developed and tested on crushed pellets. Normalized weight losses of lanthanumphosphates and europium-doped lanthanum-phosphates, measured in acidic media at 90 C, are interpreted and compared against the previous findings from the literature. The normalized dissolution rate for La and Eu within (La, Eu)PO4 is between 1.10-5 and 1.10-4 g.m-2.d-1, whereas the rate of Na, Cs and Sr in phosphate glass at room temperature in deionized water is about 1.10-2 g.m-2.d-1. Another essential parameter is their resistance to radiation. The damage created by the recoils accompanying alpha-decay can be simulated on ceramic matrices. Preliminary experiments are realized by means of ion bombardment. Kr2+ ions are implanted in La-monazite-type pellets, and the effects on the LaPO4 structure resulting from the Raman spectroscopy are poor. On a laboratory scale, the promising characteristics of the monazite mineral are found again in the synthetic phosphate. In particular, the doping of actinide surrogates is successful and the corrosion tests under repository conditions show a good resistance of the samples. The results achieved in this work confirm that among other favorable ceramics (e.g. pyrochlore) the ''monazite-route'' has to be further pursued regarding the research on the conditioning of MA.

  10. Structural design studies on a large pool type SFR of 1200MWe

    An economic improvement is a hot issue as one of the Gen IV nuclear plant goals. To secure economic competitiveness of a SFR compared to a pressurized water reactor, several structural design concepts are adapted in without loosing the reactor safety level. One is the increase of the plant capacity with the minimum number of component and loop, which leads the reduction of the plant maintenance, repair, and construction costs by a large-size scale effect. Another is the simple system arrangement, compact reactor size for only two loop system for a 1200MWe capacity of a pool type SFR, and the minimization of IHTS piping length through the properly locating the SG and secondary pump. Several researches are also studied to attain the economic improvement target of the NSSS in structural point of view; for example, an integrated concept of a refueling machine and inspection device with a long waveguide sensor for reactor internals. Fig.1 shows the reactor internals and components arrangement in reactor vessel. The outer diameter of the reactor vessel is 14.5m, which is very compact size compared to other designs, and 0.05m in thickness. It can accommodate the maximum core size of 7.9m. With the internal arrangement, the refueling availability of core assemblies was confirmed, and 36 control rods are supported and guided by upper internal structures. The material of reactor vessel and internal structure is a Type 316 stainless steel. The primary system consists of 4 sets of primary pump, IHX, and DHX in reactor vessel. The component size is not much larger than the KALIMER-600 design because the numbers of components was increased. The reactor vessel's diameter is relatively so small that the minimum space between the components is 55cm, which may not be enough for equipment maintenance. The NSSS has two intermediate heat transport loops. The each of IHTS loops outside of the reactor vessel has 2 mechanical type pumps and 2 SGs. The fabricability of the piping and elbows of the large piping diameter was investigated for realizing this system. The piping diameters for the hot and cold legs of 80 cm and 110cm respectively are within the feasible fabrication range through the both ways of forged pipe and seamless pipe. The piping length of each loop is relatively long about 180m because of the inverse U shape piping layout adapted to the preventing the pressure propagation to the reactor vessel when a sodium-water reaction accident occurs in SG upper tube. Since this long piping layout increases the maintenance cost, the shortening of the piping total length would be necessary by properly sacrificing over-excessive safety design level. The pipe material of a Mod.9Cr-1Mo can shorten the piping length about 60m compared to stainless steel, which has also a higher mechanical strength and a low thermal expansion. This has an advantage for obtaining a simple layout of IHTS piping subjected to a high temperature environment. The two-loop system is also advantageous to a compact building size because the numbers of components can be minimized, and the total piping length could be shortened. The height of the SG is about 37.4 m. The SG tube is a double-wall straight type to reduce the possibility of the water injection to the sodium side. Two new design strategies are adapted for the economic improvement of the NSSS in structural point of view. One is an integrated component of a refueling machine and an in- service inspection (ISI) tool with a long life waveguide sensor for reactor internals. This concept will shorten the overall period of about 2 days through the reduction of in-service inspection time of Rx internals.The other is a LBB technology application for IHTS piping and RV, which will reduce the construction cost because of the unnecessary of a large scale protection facilities against to sodium leak accidents. The component arrangement and reactor structural sizing for two loop systems for a 1200MWe capacity of a SFR are suggested with several structural design improved concepts to attain an economic improvement of a large s

  11. Monazite-type ceramics for conditioning of minor actinides. Structural characterization and properties

    Babelot, Carole

    2013-07-01

    The minor actinides (MA) neptunium, americium, and curium are mainly responsible for the long-term radiotoxicity of the High Active Waste (HAW) generated during the nuclear power operation. If these long-lived radionuclides are removed from the HAW by partitioning and converted by neutron fission (transmutation) into shorter-lived or stable elements, the remaining waste loses most of its long-term radiotoxicity. Thus, partitioning and transmutation (P and T) are considered as attractive options for reducing the burden on geological disposals. As an alternative, these separated MA can also be conditioned (P and C strategy) in specifically adapted ceramics to ensure their safe final disposal over long periods. At the moment, spent fuel elements are foreseen either for direct disposal in deep geological repositories or for reprocessing. The highly active liquid waste that is produced during reprocessing is conditioned industrially using a vitrification process before final disposal. Although the widely used borosilicate glasses meet most of the specifications needed, ceramic host matrices appear to be even more suitable in terms of resistance to corrosion. The development of new materials based on tailor-made highly specific ceramics with extremely stable behavior would make it possible to improve the final storage of long-lived high-level radiotoxic waste. In the framework of this PhD research project, monazite-type ceramics were chosen as promising host matrices for the conditioning of trivalent actinides. The focus on the monazite-type ceramics is justified by their properties such as high chemical durability. REPO{sub 4} ceramics are named monazite for RE = La - Gd (monoclinic symmetry) and xenotime for RE = Tb - Lu and Y (tetragonal symmetry). The objective of this study is to contribute to the understanding of the alteration behavior of such ceramics under the repository conditions. REPO{sub 4} (with RE = La, Eu) is prepared by hydrothermal synthesis at 200 C. Structural and morphological characteristics (using X-ray diffraction (XRD) and scanning electron microscope (SEM)) combined with physical and thermal properties of samples (using thermogravimetry, differential scanning calorimetry (TG-DSC) and dilatometry) are realized in order to study the behavior of monazite-type powder and pellets. The access to short-range-order spectroscopy (time resolved laser fluorescence spectroscopy (TRLFS) and extended X-ray absorption fine structure (EXAFS)) permits to understand the structure of ceramic waste forms at the molecular level. La-monazite matrices being doped with Eu (III) (as a non-radioactive chemical homologue for Am (III)) and Cm (III), TRLFS is used to explore the local structural environment of Eu and Cm within the monazite crystal structure. Eu (III) and Cm (III) are substituted on the La site of LaPO{sub 4}. The single site of Cm (III) is found in four slightly different environments which is assumed to be due to a difference in the four La sites within a LaPO4 unit cell. Structural parameters of the Eu (III) species were also analyzed by EXAFS. The nearest neighbors of Eu (III) are modeled as 9.5 oxygen atoms (N{sub O1} = 4 at r(EuO1) = 2.37 Aa, N{sub O2} = 4 at r(Eu-O2) = 2.53 Aa, and N{sub O3} = 1.5 at r(Eu-O3) = 2.83 Aa). An essential parameter that describes the stability of the host phases is their dissolution rate obtained under conditions of relevance for final repositories. In this context, a set-up is developed and tested on crushed pellets. Normalized weight losses of lanthanumphosphates and europium-doped lanthanum-phosphates, measured in acidic media at 90 C, are interpreted and compared against the previous findings from the literature. The normalized dissolution rate for La and Eu within (La, Eu)PO{sub 4} is between 1.10{sup -5} and 1.10{sup -4} g.m{sup -2}.d{sup -1}, whereas the rate of Na, Cs and Sr in phosphate glass at room temperature in deionized water is about 1.10{sup -2} g.m{sup -2}.d{sup -1}. Another essential parameter is their resistance to radiation. The damage created by the recoils accompanying alpha-decay can be simulated on ceramic matrices. Preliminary experiments are realized by means of ion bombardment. Kr{sup 2+} ions are implanted in La-monazite-type pellets, and the effects on the LaPO{sub 4} structure resulting from the Raman spectroscopy are poor. On a laboratory scale, the promising characteristics of the monazite mineral are found again in the synthetic phosphate. In particular, the doping of actinide surrogates is successful and the corrosion tests under repository conditions show a good resistance of the samples. The results achieved in this work confirm that among other favorable ceramics (e.g. pyrochlore) the ''monazite-route'' has to be further pursued regarding the research on the conditioning of MA.

  12. Structure and magnetic properties of new bcc A2-type based superstructures in R-Fe-B systems

    Two new bcc 3-dimensional superstructures based on the A2-type structure having lattice parameters an=na0 with n=2, 4 and a0=lattice parameter of the A2-type basic structure, have been obtained either by quenching the melts at moderate cooling rates or by crystallizing glasses of alloys close to compositions R2-xFe14B (0< x≤1, R=rare earth metal or Y). These bcc compounds are soft magnetic with Curie temperatures in the range 400 to 600 K. Composite hard magnetic exchange-spring type magnets are obtained upon their decomposition at about 1000 K. (orig.)

  13. The Electronic Structure of CdSe/CdS Core/Shell Seeded Nanorods: Type-I or Quasi-Type-II?

    Eshet, Hagai; Grünwald, Michael; Rabani, Eran

    2013-01-01

    The electronic structure of CdSe/CdS core/shell seeded nanorods of experimentally relevant size is studied using a combination of molecular dynamics and semiempirical pseudopotential techniques, with the aim to address the transition from type-I to a quasi-type-II band alignment. The hole is found to be localized in the core region regardless of its size. The overlap of the electron density with the core region depends markedly on the size of the CdSe core: For small cores, we observe little ...

  14. Non-degenerate homogeneous $\\epsilon$-K\\"ahler and $\\epsilon$-quaternion K\\"ahler structures of linear type

    Luján, Ignacio; Swann, Andrew

    2013-01-01

    We study the class of non-degenerate homogeneous structures of linear type in the pseudo-K\\"ahler, para-K\\"ahler, pseudo-quaternion K\\"ahler and para-quaternion K\\"ahler cases. We show that these structures characterize spaces of constant holomorphic, para-holomorphic, quaternion and para-quaternion sectional curvature respectively. In addition the corresponding homogeneous models are computed, exhibiting the relation between these kind of structures and the incompleteness of the metric.

  15. The type I error rate for in vivo Comet assay data when the hierarchical structure is disregarded

    Hansen, Merete Kjær; Kulahci, Murat

    combinations the type I error rate is greater than the nominal _ at 0.05. Closed-form expressions based on scaled F-distributions using the Welch-Satterthwaite approximation are provided to show how the type I error rate is aUected. With this study we hope to motivate researchers to be more precise regarding...... this imposes considerable impact on the type I error rate. This study aims to demonstrate the implications that result from disregarding the hierarchical structure. DiUerent combinations of the factor levels as they appear in a literature study give type I error rates up to 0.51 and for all...

  16. Singularity Structures in Coulomb-Type Potentials in Two-Body Dirac Equations of Constraint Dynamics

    Two-body Dirac equations (TBDE) of Dirac's relativistic constraint dynamics have been successfully applied to obtain a covariant nonperturbative description of QED and QCD bound states. Coulomb-type potentials in these applications lead naively in other approaches to singular relativistic corrections at short distances that require the introduction of either perturbative treatments or smoothing parameters. We examine the corresponding singular structures in the effective potentials of the relativistic Schroedinger equation obtained from the Pauli reduction of the TBDE. We find that the relativistic Schroedinger equation leads in fact to well-behaved wave function solutions when the full potential and couplings of the system are taken into account. The most unusual case is the coupled triplet system with S=1 and L={(J-1),(J+1)}. Without the inclusion of the tensor coupling, the effective S-state potential would become attractively singular. We show how including the tensor coupling is essential in order that the wave functions be well-behaved at short distances. For example, the S-state wave function becomes simply proportional to the D-state wave function and dips sharply to zero at the origin, unlike the usual S-state wave functions. Furthermore, this behavior is similar in both QED and QCD, independent of the asymptotic freedom behavior of the assumed QCD vector potential. Light- and heavy-quark meson states can be described well by using a simplified linear-plus-Coulomb-type QCD potential apportioned appropriately between world scalar and vector potentials. We use this potential to exhibit explicitly the origin of the large pi-rho splitting and effective chiral symmetry breaking. The TBDE formalism developed here may be used to study quarkonia in quark-gluon plasma environments

  17. Structure, process, and outcomes of care in a telemonitoring program for patients with type 2 diabetes

    Nocella, Jill M; Dickson, Victoria Vaughan; Cleland, Charles M; Melkus, Gail D’Eramo

    2016-01-01

    Background Using Donabedian’s structure-process-outcomes (SPO) framework, this descriptive, exploratory study examined the structure of a telemonitoring program in a population of patients with type 2 diabetes (T2D), the process of nurse–patient telephonic interactions, and patients’ clinical outcomes. Methods Secondary data analysis was conducted using data from 581 patients who participated in a home telemonitoring program for 12 months. Three point-biserial and six Pearson correlations were estimated to determine how patient demographics related to clinical characteristics. Mixed model regressions were conducted predicting hemoglobin A1c (HbA1c), systolic blood pressure (SBP), and diastolic blood pressure (DBP) levels at 6, 9, and 12 months based on the frequency of contact in the earlier 3 months. Analysis of variances were conducted to assess if the frequency of contact was significantly different by change in HbA1c levels from 3 to 6, 6 to 9, and 9 to 12 months. Results Significant negative correlations were found between age and HbA1c (r=−0.10, P=0.015) and DBP (r=−0.16, P<0.001), a significant positive correlation was found between age and SBP (r=0.15, P=0.001). A significant correlation was found between sex and DBP (rpb=−0.11, P=0.015); female participants had lower DBP levels than males. Frequency of contact was not related to the change in clinical outcomes. However, the frequency of contact for the time period 3 to 6 months was associated with change in HbA1c for the 6- to 9- month period and frequency of contact during the 6- to 9- month period was associated with change in HbA1c from 9 to 12 months. Conclusion Examination of the SPO measures in the telemonitoring environment assisted in understanding the effectiveness of this type of unique intervention and the need for further in-depth exploration of self-management techniques among individuals with T2D. PMID:27042150

  18. Structural Approach and Luminescence Properties of La 1/6Pb 1/3Zr 2(PO 4) 17/6(SiO 4) 1/6:Eu 3+

    Bakhous, K.; Cherkaoui, F.; Benabad, A.; Jouhari, N. El; Savariault, J. M.; Dexpert-Ghys, J.

    1999-09-01

    Rare earth phosphosilicates (Li1-xEux)1/6Pb1/3Zr2(PO4)17/6(SiO4)1/6 0≤x≤1 have been synthesized via a sol-gel route. The powder X-ray diffraction has been analyzed with the Nasicon-type structure. The Rietveld analysis of the structure performed in space group Roverline3 shows a statistical distribution of ions La3+, Eu3+, and Pb2+ over the positions 3a (occupation 10%) and 3b (occupation 90%) of the so-called M1 site. In agreement with these results, the Eu3+ luminescence analysis in these phases exhibits two sites for Eu3+, both are noncentrosymmetric, revealing a local disorder in the compounds, which is also supported by the inhomogeneous broadening of the emission lines. The luminescence characteristics of this family of silicates have been investigated for various x values. Under excitation at 254 nm, the distinct emissions of Pb2+ and of Eu3+ are observed. The excitation of Eu3+ ions occurs directly via the charge transfer state or after Pb2+→Eu3+ energy transfer. Concentration quenching of the Eu3+ emission is also investigated.

  19. Effect of annealing temperature on the structural, photoluminescence and magnetic properties of sol-gel derived Magnetoplumbite-type (M-type) hexagonal strontium ferrite

    Teh, Geok Bee, E-mail: sharonteh2009@gmail.com [Division of Bioscience and Chemistry, School of Arts and Science, Tunku Abdul Rahman College, Jalan Genting Kelang, 53300 Kuala Lumpur (Malaysia); Wong, Yat Choy [Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, PO Box 218, Hawthorn, Victoria 3122 (Australia); Tilley, Richard D. [School of Chemical and Physical Sciences, MacDiarmid Institute of Advanced Materials and Nanotechnology, Victoria University of Wellington, PO Box 600, Wellington (New Zealand)

    2011-09-15

    Magnetoplumbite-type (M-type) hexagonal strontium ferrite particles were synthesized via sol-gel technique employing ethylene glycol as the gel precursor at two different calcination temperatures (800 and 1000 deg. C). Structural properties were systematically investigated via X-ray diffraction (XRD), field emission scanning electron microscopy, high resolution transmission electron microscopy (HRTEM), energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA), photoluminescence spectrophotometry and superconducting quantum interference device magnetometer. XRD results showed that the sample synthesized at 1000 deg. C was of single-phase with a space group of P6{sub 3}/mmc and lattice cell parameter values of a=5.882 A and c=23.048 A. EDS confirmed the composition of strontium ferrite calcined at 1000 deg. C being mainly of M-type SrFe{sub 12}O{sub 19} with HRTEM micrographs confirming the ferrites exhibiting M-type long range ordering along the c-axis of the crystal structure. The photoluminescence (PL) property of strontium ferrite was examined at excitation wavelengths of 260 and 270 nm with significant PL emission peaks centered at 350 nm being detected. Strontium ferrite annealed at higher temperature (1000 deg. C) was found to have grown into larger particle size, having higher content of oxygen vacancies and exhibited 83-85% more intense PL. Both the as-prepared strontium ferrites exhibited significant oxygen vacancies defect structures, which were verified via TGA. Higher calcination temperature turned strontium ferrite into a softer ferrite. - Highlights: > High annealing temperature produced M-type ferrite with higher oxygen vacancies. > Photoluminescence intensity is proportional to the existence of oxygen vacancies. > XRD data showed cell contraction well suited to the change of oxygen vacancies. > Shift in hysteresis loop due to defect-induced exchange bias was observed.

  20. Effect of annealing temperature on the structural, photoluminescence and magnetic properties of sol-gel derived Magnetoplumbite-type (M-type) hexagonal strontium ferrite

    Magnetoplumbite-type (M-type) hexagonal strontium ferrite particles were synthesized via sol-gel technique employing ethylene glycol as the gel precursor at two different calcination temperatures (800 and 1000 deg. C). Structural properties were systematically investigated via X-ray diffraction (XRD), field emission scanning electron microscopy, high resolution transmission electron microscopy (HRTEM), energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA), photoluminescence spectrophotometry and superconducting quantum interference device magnetometer. XRD results showed that the sample synthesized at 1000 deg. C was of single-phase with a space group of P63/mmc and lattice cell parameter values of a=5.882 A and c=23.048 A. EDS confirmed the composition of strontium ferrite calcined at 1000 deg. C being mainly of M-type SrFe12O19 with HRTEM micrographs confirming the ferrites exhibiting M-type long range ordering along the c-axis of the crystal structure. The photoluminescence (PL) property of strontium ferrite was examined at excitation wavelengths of 260 and 270 nm with significant PL emission peaks centered at 350 nm being detected. Strontium ferrite annealed at higher temperature (1000 deg. C) was found to have grown into larger particle size, having higher content of oxygen vacancies and exhibited 83-85% more intense PL. Both the as-prepared strontium ferrites exhibited significant oxygen vacancies defect structures, which were verified via TGA. Higher calcination temperature turned strontium ferrite into a softer ferrite. - Highlights: → High annealing temperature produced M-type ferrite with higher oxygen vacancies. → Photoluminescence intensity is proportional to the existence of oxygen vacancies. → XRD data showed cell contraction well suited to the change of oxygen vacancies. → Shift in hysteresis loop due to defect-induced exchange bias was observed.