WorldWideScience
1

Trivalent praseodymium ion conducting solid electrolyte composite with NASICON type structure  

Energy Technology Data Exchange (ETDEWEB)

New trivalent praseodymium ion (Pr{sup 3+}) conducting solid electrolyte composites, (Pr{sub x}Zr{sub 1-x}){sub 4/(4-x)}Nb(PO{sub 4}){sub 3} (0.05{<=}x{<=}0.3)+NbPO{sub 5}, 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 Pr{sup 3+} ion conduction in the composite solid was demonstrated both by ac conductivity measurements in various oxygen partial pressures and by dc electrolytes.

Hasegawa, Y.; Tamura, S.; Imanaka, N.; Adachi, G.; Takano, Y.; Tsubaki, T.; Sekizawa, K

2004-07-28

2

Synthesis and Vitrification of Nasicon Type Lithium Borophosphate Glasses  

Science.gov (United States)

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.

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

2013-07-01

3

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

International Nuclear Information System (INIS)

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

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2009-03-31

5

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

Science.gov (United States)

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

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

2013-05-01

6

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

Science.gov (United States)

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.

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

2012-12-01

7

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

OpenAIRE

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 ?-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...

Amp Ric Hatert, Fr Amp D.

2009-01-01

8

Structure and conductivity of the NASICON analog Na3SC2(PO4)3  

International Nuclear Information System (INIS)

Neutron and x-ray diffraction data of Na3SC2(PO4)3 are presented that show the transition from an ordinary-conducting, high temperature phase to a still higher temperature, superionic conducting phase. There are at least four polymorphic modifications. At room temperature, the refined neutron diffraction data confirm the Cc space group reported by Efremov and Kalinin but with a = 16.0449(24), b = 8.9225(15), c = 9.0656(13)A, #betta# = 126.918(21), R/sub weighted pattern/ = 17.5%, and R/sub expected/ = 7%. Between 250C and 640C, a second polymorph appears. The structure is monoclinic but has not yet been refined. At 640C, a third polymorph C appears. It is rhombohedral R3c. Using hexagonal axes, a = 8.9273(2), c = 22.3668A, R/sub wp/ = 6.28% and R/sub e/ = 3.83% at 1000C. At 1660C, the high temperature polymorph D appears. It is the superconducting phase of NASICON(Sc). It, too, is rhombohedral R3c with a = 8.9274(1), c = 22.5493(6)A, R/sub wp/ = 5.81% and R/sub e/ = 3.87% at 2250C. The diffraction data are correlated with ionic conductivity measurements as a function of temperature

9

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

Science.gov (United States)

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

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

2008-06-21

10

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

International Nuclear Information System (INIS)

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 condu

11

Ion conductivity of nasicon ceramics  

International Nuclear Information System (INIS)

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 ? double-prime-alumina ceramics. It is well known that the ion conductivity of ?-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 amountsamounts

12

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

International Nuclear Information System (INIS)

Vanadyl(V)–titanium–orthophosphate (VVO)TiIV6(PO4)9 is formed by solid state reactions in the temperature range 525???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. - Graphical abstract: (VVO)TiIV6(PO4)9 belongs to the NASICON structu the NASICON structure family. Its structure contains [TiIV2O9] double-octahedra and unprecedented, strongly distorted tetrahedral [(VV=O)O3] groups, in stark contrast to other members of this family. The structure model is in agreement with the results from MAS-NMR (31P, 51V) spectroscopy. Highlights: ? Equilibrium relations for the subsolidus have been established for the system TiO2/V2O5/P2O5. ? Phase formation has been monitored by XRPD as well as by 31P- and 51-MAS-NMR. ? A solid solution Ti(P1?xVx)2O7 exists up to x=0.43 with a miscibility gap at 0.23?x?0.30. ? The crystal structure of the new NASICON-related phosphate (VVO)TiIV6(PO4)9 is reported. ? The crystal structure contains the unprecedented [(V=O)O3] group.

13

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  

Energy Technology Data Exchange (ETDEWEB)

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)

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

2010-07-01

14

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

Directory of Open Access Journals (Sweden)

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.

Fuentes, R. O.

1999-12-01

15

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

Directory of Open Access Journals (Sweden)

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.

Nikolay S. Slobodyanik

2012-07-01

16

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

Science.gov (United States)

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 ? 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

Arbi, K; París, M A; Sanz, J

2011-10-21

17

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

Directory of Open Access Journals (Sweden)

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.

Santamaría, J.

2010-02-01

18

Effect of decomposition on the densification and properties of NASICON ceramic electrolytes  

Energy Technology Data Exchange (ETDEWEB)

Processing and characterization of NASICON ceramic electrolytes have been conducted using a number of different techniques. Sintering of these materials was accomplished at temperatures between 1100/sup 0/C and 1375/sup 0/C. Results of this work have shown that NASICON ceramics with compositions around x=2 (i.e., Na/sub 3/Zr/sub 2/Si/sub 2/Po/sub 12/), are not monophase, possess poor mechanical strength and an anomalous thermal expansion behavior, and are subject to chemical instability in the presence of liquid sodium (at 300/sup 0/C). Using wet-chemical techniques, x-ray diffraction analysis, and SEM observations, it was found that NASICON apparently exhibits phase and chemical decomposition at densification temperatures. The products of this decomposition process can be correlated with the poor physical and corrosion-resistant properties.

McEntire, B J; Bartlett, R A; Miller, G R; Gordon, R S

1982-03-01

19

Sintering of polycrystalline ionic conductors:. beta. ''-Al/sub 2/O/sub 3/ and NASICON  

Energy Technology Data Exchange (ETDEWEB)

The densification kinetics for both ..beta..''-alumina and NASICON are dramatically different. ..beta..''-Alumina sinters by a reactive liquid process whereas NASICON densifies by a solid state method. More importantly, a qualitative examination of particle and agglomerate distributions, phase composition, linear shrinkage analysis, and heating rate effects can result in a concise determination of sintering processes without recourse to more quantitative techniques. Such a simple procedural method should be a basis for any beginning investigative study into the densification mechanism of new multicomponent ceramic materials.

McEntire, B J; Miller, G R; Gordon, R S

1979-01-01

20

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

International Nuclear Information System (INIS)

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

21

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  

International Nuclear Information System (INIS)

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, 7Lp>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.

22

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

International Nuclear Information System (INIS)

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

23

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2009-02-20

24

Caustic Recycle from Hanford Tank Waste Using NaSICON Ceramic Membranes  

International Nuclear Information System (INIS)

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

25

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

Science.gov (United States)

Structural sites occupied by lithium in the rhombohedral LiTi2-xZrx(PO4)3 series (0 ions occupy M1 sites; however, in the second one Li occupy intermediate M1/2 sites. As the temperature increases, a first-order displacive transformation is detected in the triclinic phase, but a second-order/disorder transition is detected in the rhombohedral phase. From the temperature dependence of the 7Li NMR quadrupole constant (CQ) of the two compounds, the evolution of M1 and M1/2 sites occupancy in the 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

Arbi, K; París, M A; Sanz, J

2006-04-01

26

Parsing with Typed Feature Structures  

CERN Document Server

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...

Wintner, S; Wintner, Shuly; Francez, Nissim

1996-01-01

27

Parsing with Typed Feature Structures  

CERN Document Server

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.

Wintner, S; Wintner, Shuly; Francez, Nissim

1996-01-01

28

Ion conductivity of Nasicon ceramics: effects of texture and doping with B[sub 2]O[sub 3] and Al[sub 2]O[sub 3  

Energy Technology Data Exchange (ETDEWEB)

The Nasicon[sub ss], Na[sub 1+x]Zr[sub 2]Si[sub x]P[sub 3-x]O[sub 12], 0Nasicon ceramics. Ceramics of bulk composition Na[sub 2.94]Zr[sub 1.49]Si[sub 2.20]P[sub 0.80]O[sub 10.85] 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 3.65x10[sup 3] [Omega]cm to 1.23x10[sup 3] [Omega]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 [Omega]cm at 25 C. B[sub 2]O[sub 3]- and Al[sub 2]O[sub 3]-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. (orig.)

Hoej, J.W. (Inst. of Mineral Industry, Technical Univ., Lyngby (Denmark)); Engell, J. (Inst. of Mineral Industry, Technical Univ., Lyngby (Denmark))

1993-06-20

29

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  

Energy Technology Data Exchange (ETDEWEB)

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}.

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

2013-02-25

30

Abstract Machine for Typed Feature Structures  

CERN Document Server

This paper describes an abstract machine for linguistic formalisms that are based on typed feature structures, such as HPSG. The core design of the abstract machine is given in detail, including the compilation process from a high-level language to the abstract machine language and the implementation of the abstract instructions. The machine's engine supports the unification of typed, possibly cyclic, feature structures. A separate module deals with control structures and instructions to accommodate parsing for phrase structure grammars. We treat the linguistic formalism as a high-level declarative programming language, applying methods that were proved useful in computer science to the study of natural languages: a grammar specified using the formalism is endowed with an operational semantics.

Wintner, S; Wintner, Shuly; Francez, Nissim

1995-01-01

31

Types of provincial structure and population health.  

Science.gov (United States)

This paper explores the potential of using large administrative units for studies of population health within a country. The objective is to illustrate a new way of defining structural dimensions and to use them in examining variation in life expectancy rates. We use data from the 50 provinces of Spain as a case study. A factor analysis of organizational items such as schools, hotels and medical personnel is employed to define and generate "collective" measures for well-known provincial types, in this case: urban, commercial, industrial and tourist provinces. The scores derived from the factor analysis are then used in a regression model to predict life expectancy. The City-centered and Commercial provinces showed positive correlations with life expectancy while those for the Tourist provinces were negative. The industrial type was nonsignificant. Explanations of these correlations are proposed and the advantages and disadvantages of this exploratory technique are reviewed. The use of this technique for generating an overview of social organization and population health is discussed. PMID:15482869

Young, Frank W; Rodriguez, Eunice

2005-01-01

32

Interference enhanced thermoelectricity in quinoid type structures  

Science.gov (United States)

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 ?-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 S2G and figure of merit ZT, where S is the Seebeck coefficient, making quinoid type molecules potential candidates for efficient thermoelectric devices.

Strange, M.; Seldenthuis, J. S.; Verzijl, C. J. O.; Thijssen, J. M.; Solomon, G. C.

2015-02-01

33

Lie-admissible structures on Witt type algebras  

Science.gov (United States)

In this paper we study Lie-admissible structures on Witt type algebras. Witt type algebras are ?-graded Lie algebras (where ? is an abelian group) which generalize the Witt algebra. We give all third power-associative and flexible Lie-admissible structures on these algebras. In particular we generalize some results on the Witt algebra. After describing the second scalar cohomology group of Witt type algebras, we investigate third power-associative and flexible Lie-admissible structures on the central extension of some Witt type algebras. Finally we study a left-symmetric structure induced by a symplectic form for some Witt type algebras.

Benayadi, Saïd; Chopp, Mikaël

2011-02-01

34

Parameterized type expansion in the feature structure formalism TDL  

OpenAIRE

Over the last few years, unification-based grammar formalisms have become the predominant paradigm in natural language processing systems because of their monotonicity, declarativeness, and reversibility. From the viewpoint of computer science, typed feature structures can be seen as data structures that allow representation of linguistic knowledge in a uniform fashion. Type expansion is an operation that makes the constraints on a typed feature structure explicit and determines their satisfi...

Scha?fer, Ulrich

1995-01-01

35

Vibrational spectra of complex oxides with the perovskite type structure  

International Nuclear Information System (INIS)

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

36

Types and Functions of Coastal Structures  

DEFF Research Database (Denmark)

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 water intakes and outfalls.

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

2003-01-01

37

Structural biology of type VI secretion systems  

OpenAIRE

Type VI secretion systems (T6SSs) are transenvelope complexes specialized in the transport of proteins or domains directly into target cells. These systems are versatile as they can target either eukaryotic host cells and therefore modulate the bacteria–host interaction and pathogenesis or bacterial cells and therefore facilitate access to a specific niche. These molecular machines comprise at least 13 proteins. Although recent years have witnessed advances in the role and function of these...

Cascales, Eric; Cambillau, Christian

2012-01-01

38

Stochastic Fatigue Analysis of Jacket Type Offshore Structures  

DEFF Research Database (Denmark)

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.

Sigurdsson, Gudfinnur

1988-01-01

39

Stochastic Fatigue Analysis of Jacket Type Offshore Structures  

OpenAIRE

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.

Sigurdsson, Gudfinnur

2010-01-01

40

Prediction of type A behaviour: A structural equation model  

OpenAIRE

The predictability of Type A behaviour was measured in a sample of 375 professionals with a shortened version of the Jenkins Activity Survey (JAS). Two structural equation models were constructed with the Type A behaviour achievement sub-scale and global (total) Type A as the predictor variables. The indices showed a reasonable-to-promising fit with the data. Type A achievement was reasonably predicted by service-career orientation, internal locus of control, power self-concept and economic i...

Marius Pretorius; Gideon Nieman; Jurie van Vuuren; Boshoff, Andre? B.; René van Wyk

2009-01-01

41

Prediction of Type A behaviour : a structural equation model  

OpenAIRE

The predictability of Type A behaviour was measured in a sample of 375 professionals with a shortened version of the Jenkins Activity Survey (JAS). Two structural equation models were constructed with the Type A behaviour achievement sub-scale and global (total) Type A as the predictor variables. The indices showed a reasonable-to-promising fit with the data. Type A achievement was reasonably predicted by service-career orientation, internal locus of control, power self-concept...

Wyk, Rene; Boshoff, A. B.; Nieman, Gideon; Vuuren, Jurie Jansen; Pretorius, Marius

2009-01-01

42

Magnetic structure of Laves type superlattices  

Science.gov (United States)

We present a determination of the magnetic structures of two superlattices of the form [6 ˜nm DyFe2 / 6 nm ErFe_2] and [8 nm DyFe2 / 4 ˜nm ErFe_2], both prepared by molecular beam epitaxy on a sapphire (11\\overline20) substrate. The layers crystallize in the fcc Laves phase structure with the surface normal being along [110]. The experiments were carried out using neutron diffraction on the triple-axis spectrometer C5 at the NRU reactor in Chalk River. We measured in zero field and in a horizontal field of 2.6 ˜T applied along [001], which is the easy axis for bulk DyFe_2, along [111], which is the easy axis of bulk ErFe_2, and along the surface normal [110]. The temperature was varied in the range from 4 ˜K to 250 ˜K. The data analysis shows that the direction of the magnetization is a delicate balance between the Zeeman energy favoring the field direction, the crystalline anisotropies favoring either the [001] or [111] direction, and the exchange interaction at the interface favoring a parallel orientation of the magnetizations of both layers. Surprisingly we find that the moments rotate out of the plane on cooling even when constrained by an in-plane field along [001].

Fritzsche, H.; Buyers, W.; Yamani, Z.; Tun, Z.; Cowley, R.; Ward, R.

2004-03-01

43

Type II Cadherin Ectodomain Structures: Implications for Classical Cadherin Specificity  

Energy Technology Data Exchange (ETDEWEB)

Type I and II classical cadherins help to determine the adhesive specificities of animal cells. Crystal-structure determination of ectodomain regions from three type II cadherins reveals adhesive dimers formed by exchange of N-terminal {beta} strands between partner extracellular cadherin-1 (EC1) domains. These interfaces have two conserved tryptophan side chains that anchor each swapped strand, compared with one in type I cadherins, and include large hydrophobic regions unique to type II interfaces. The EC1 domains of type I and type II cadherins appear to encode cell adhesive specificity in vitro. Moreover, perturbation of motor neuron segregation with chimeric cadherins depends on EC1 domain identity, suggesting that this region, which includes the structurally defined adhesive interface, encodes type II cadherin functional specificity in vivo.

Patel,S.; Ciatto, C.; Chen, C.; Bahna, F.; Rajebhosale, M.; Arkus, N.; Schieren, I.; Jessell, T.; Honig, B.

2006-01-01

44

Cooling structure for FBR type reactor wall  

International Nuclear Information System (INIS)

Low temperature sodium is introduced between a reactor wall and a cylindrical shell disposed at the inner side of the reactor wall, so that the high temperature sodium at the inner side of the cylindrical shell is not brought into contact with the reactor wall. The cylindrical shell comprises a highly rigid structure having a higher proper oscillation than the frequency of accompanying vibrations by coupled oscillations caused by oval vibrations excited to the cylindrical shell. A top flange is disposed being bent toward the wall at the upper end of the cylindrical shell. The joined portion of the cylindrical shell and the top flange is formed in an arcuate configuration. The thickness of the cylindrical shell is within a range of from 16 to 20mm, and the thickness of the top flange is within a range of from 30 to 90mm. This can keep high strength while avoiding a state undergoing severe heat stresses. In addition, excitation of the oval vibrations applied to the cylindrical shell is prevented, to avoid occurrence of coupled oscillation of fluid. (I.N.)

45

Infrared spectra and structures of aniline +-furan and aniline +-phenol. Preference between ?-type and ?-type hydrogen-bonded structures  

Science.gov (United States)

Infrared photodissociation spectra of aniline +-M (M=thiophene, furan and phenol) are measured in the 2700-3700 cm -1 region and analyzed by density functional theory calculations. Only a structure involving a ?-type hydrogen bond is found for aniline +-thiophene. Two structural isomers are identified for aniline +-furan and aniline +-phenol, which have either a ?-type or a ?-type hydrogen bond, where an amino proton of aniline + interacts with the ?-electrons or the oxygen atom of the neutral molecules, respectively. The isomer with a ?-type hydrogen bond is more stable for aniline +-phenol, while less stable for aniline +-furan.

Honkawa, Yoshiki; Inokuchi, Yoshiya; Ohashi, Kazuhiko; Nishi, Nobuyuki; Sekiya, Hiroshi

2003-07-01

46

Probabilistic Evaluation of Fuselage-Type Composite Structures  

Science.gov (United States)

A methodology is developed to simulate computationally the uncertain behavior of composite structures. The uncertain behavior includes buckling loads, natural frequencies, displacements, stress/strain, etc., which are the consequences of the random variation (scatter) of the primitive (independent random) variables in the constituent, plv. laminate and structural levels. This methodology is implemented in a computer code integrated probabilistic assessment of composite structures (IPACS). A fuselage-type composite structure is analyzed to demonstrate the code's capability . The probability distribution functions of the buckling loads, natural frequency, displacement, strain and stress are computed. The sensitivity of each primitive (independent random) variable to a given structural response is also identified from the analyses.

Shiao, Michael C.; Chamis, Christos C.

1998-01-01

47

Soil structure interactions of eastern U.S. type earthquakes  

International Nuclear Information System (INIS)

Two types of earthquakes have occurred in the eastern US in the past. One of them was the infrequent major events such as the 1811-1812 New Madrid Earthquakes, or the 1886 Charleston Earthquake. The other type was the frequent shallow earthquakes with high frequency, short duration and high accelerations. Two eastern US nuclear power plants, V.C Summer and Perry, went through extensive licensing effort to obtain fuel load licenses after this type of earthquake was recorded on sites and exceeded the design bases beyond 10 hertz region. This paper discusses the soil-structure interactions of the latter type of earthquakes

48

Correlations of Amino Acids with Secondary Structure Types: Connection with Amino Acid Structure  

OpenAIRE

The correlations of primary and secondary structures were analyzed using proteins with known structure from Protein Data Bank. The correlation values of amino acid type and the eight secondary structure types at distant position were calculated for distances between -25 and 25. Shapes of the diagrams indicate that amino acids polarity and capability for hydrogen bonding have influence on the secondary structure at some distances. Clear preference of most of the amino acids t...

Malkov, Sasa; Zivkovic, Miodrag V.; Beljanski, Milos V.; Zaric, Snezana D.

2005-01-01

49

Coexistence of Cluster Structure and Mean-field-type Structure in Medium-weight Nuclei  

International Nuclear Information System (INIS)

We have studied the coexistence of cluster structure and mean-field-type structure in 20Ne and 40Ca using Antisymmetrized Molecular Dynamics (AMD) + Generator Coordinate Method (GCM). By energy variation with new constraint for clustering, we calculate cluster structure wave function. Superposing cluster structure wave functions and mean-field-type structure wave function, we found that 8Be-12C, ?-36Ar and 12C-28Si cluster structure are important components of K? = 03+ band of 20Ne, that of normal deformed band of 40Ca and that of super deformed band of 40Ca, respectively

50

A genetic and computational approach to structurally classify neuronal types  

OpenAIRE

The importance of cell types in understanding brain function is widely appreciated but only a tiny fraction of neuronal diversity has been catalogued. Here, we exploit recent progress in genetic definition of cell types in an objective structural approach to neuronal classification. The approach is based on highly accurate quantification of dendritic arbor position relative to neurites of other cells. We test the method on a population of 363 mouse retinal ganglion cells. For each cell, we de...

Su?mbu?l, Uygar; Song, Sen; Mcculloch, Kyle; Becker, Michael; Lin, Bin; Sanes, Joshua R.; Masland, Richard H.; Seung, H. Sebastian

2014-01-01

51

Structure and Regulation of the Type VI Secretion System  

OpenAIRE

The type VI secretion system (T6SS) is a complex and widespread gram-negative export pathway with the capacity to translocate protein effectors into a diversity of target cell types. Current structural models of the T6SS indicate that the apparatus is composed of at least two complexes, a dynamic bacteriophage-like structure and a cell envelope-spanning membrane-associated assembly. How these complexes interact to promote effector secretion and cell targeting remains a major question in the f...

Silverman, Julie M.; Brunet, Yannick R.; Cascales, Eric; Mougous, Joseph D.

2012-01-01

52

Transient electromagnetic and structure analysis of BELlows type vacuum vessels  

International Nuclear Information System (INIS)

The authors performed transient electromagnetic and structure analysis of vacuum vessels, which employ bellows for one-turn resistance. BELTEM (Code for BELlows type vacuum vessel in Transient Electromagnetic and Mechanical analysis) system was developed in this work. The authors emphasize, in the present paper, that several modes of the electromagnetic force are induced in the bellows due to its corrugation and they have a significant influence on the structure design of vacuum vessel

53

Structural investigation of Eu2+ emissions from alkaline earth zirconium phosphate  

International Nuclear Information System (INIS)

Eu2+ doped A0.5Zr2(PO4)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 Eu2+ ions in the host structure, 3a and 3b. The Eu-O bond lengths were increased by changing alkaline earth ions from Ca to Ba, causing Eu2+ 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 Eu2+ emissions is proposed for the Eu2+ doped NASICON phosphor. - Graphical abstract: Eu2+ doped NASICON structured A0.5Zr2(PO4)3 (A=Ca, Sr, Ba) showed the blue and blue-green colored emissions attributed to 4f65d1-4f7 transitions. The photoluminescent properties are discussed in terms of crystal field strength and nephelauxetic effect using powder X-ray Rietveld analysis.

54

Prediction of Type A behaviour: a structural equation model  

Scientific Electronic Library Online (English)

Full Text Available SciELO South Africa | Language: English Abstract in english The predictability of Type A behaviour was measured in a sample of 375 professionals with a shortened version of the Jenkins Activity Survey (JAS). Two structural equation models were constructed with the Type A behaviour achievement sub-scale and global (total) Type A as the predictor variables. Th [...] e indices showed a reasonable-to-promising fit with the data. Type A achievement was reasonably predicted by service-career orientation, internal locus of control, power self-concept and economic innovation. Type A global was also predicted by internal locus of control, power self-concept and the entrepreneurial attitude of achievement and personal control.

René, van Wyk; André B., Boshoff; Gideon, Nieman; Jurie, van Vuuren; Marius, Pretorius.

55

Effect of nuclear structure on Type Ia supernova nucleosynthesis  

OpenAIRE

The relationship among nuclear structure, the weak processes in nuclei, and astrophysics becomes quite apparent in supernova explosion and nucleosynthesis studies. In this brief article, I report on progress made in the last few years on calculating electron capture and beta-decay rates in iron-group nuclei. I also report on applications of these rates to Type-Ia nucleosynthesis studies.

Dean, D. J.

2000-01-01

56

Extended radio structure of BL Lac type objects  

International Nuclear Information System (INIS)

The results are reported of an investigation of the arc-second radio structure of a sample of 11 BL Lac type objects which show that they possess the general core-halo morphology predicted by the so-called Blazer models although compact jet-like features are much less conspicuous in these objects than in quasars. (U.K.)

57

Prediction of type A behaviour: A structural equation model  

Directory of Open Access Journals (Sweden)

Full Text Available The predictability of Type A behaviour was measured in a sample of 375 professionals with a shortened version of the Jenkins Activity Survey (JAS. Two structural equation models were constructed with the Type A behaviour achievement sub-scale and global (total Type A as the predictor variables. The indices showed a reasonable-to-promising fit with the data. Type A achievement was reasonably predicted by service-career orientation, internal locus of control, power self-concept and economic innovation. Type A global was also predicted by internal locus of control, power self-concept and the entrepreneurial attitude of achievement and personal control.

How to cite this article:

Van Wyk, R., Boshoff, A.B., Nieman, G., Van Vuuren, J., & Pretorius, M. (2009. Prediction of type A behaviour: A structural equation model. SA Journal of Industrial Psychology/SA Tydskrif vir Bedryfsielkunde, 35(1, Art. #758, 9 pages. DOI: 10.4102/sajip.v35i1.758

Marius Pretorius

2009-04-01

58

Extended, regular HI structures around early-type galaxies  

CERN Document Server

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 remaining cases we find the HI distributed in irregular tails or clouds offset from the galaxy. The giant, regular HI structures can be up to ~200 kpc in diameter and contain up to 10^10 M_sun of HI. The incidence of irregular HI structures appears to be somewhat higher in elliptical galaxies, but the large, regular structures are observed in both elliptical and S0 galaxies and are not strictly connected to the presence of a stellar disk. If these two types of galaxies are the result of different formation paths, this is ...

Oosterloo, T; Sadler, E M; Van der Hulst, J M; Serra, P

2007-01-01

59

Equipment and building structures ageing management for WWER type NPPs  

International Nuclear Information System (INIS)

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

60

Magnetic mirror structure for testing shell-type quadrupole coils  

Energy Technology Data Exchange (ETDEWEB)

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.

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

61

Crystal structure of activin receptor type IIB kinase domain.  

Science.gov (United States)

Activin receptor type IIB (ActRIIB) belongs to a type II transforming growth factor-? (TGF-?) serine/threonine kinase receptor family which is integral to the activin and myostatin signaling pathway. Actvin and myostatin bind to activin type II receptors (ActRIIA and ActRIIB), and the glycine-serine-rich domains of type I receptors are phosphorylated by type II receptors. Activin enhances follicle-stimulating hormone biosynthesis and secretion and is involved in apoptosis, fibrosis, inflammation, and neurogenesis. Because of its essential role, activin is regarded as a novel drug target. Myostatin, also referred as growth and differentiation factor 8 (GDF-8), modulates skeletal muscle growth and has been a therapeutic target for disease conditions such as muscular dystrophy, sarcopenia, cashexia, and diabetes mellitus. The AcRIIB kinase domain from human represents a distinct type II receptor serine/threonine kinase subfamily identifiable in part by common features of Thr265 as a gatekeeper residue and back pocket supported by Phe247. The human ActRII kinase domain structure provides a basis for a more integrated understanding of substrate recognition and catalysis and will also be of help for developing chemical inhibitors. PMID:21353874

Han, Seungil

2011-01-01

62

The waveguide structures of the inverted-rib type  

Science.gov (United States)

This paper presents an analysis of the possibilities of producing waveguide structures of the inverted-rib type. Such structures can be produced on the basis of planar gradient strip waveguides (channel waveguides) produced in a glass substrate by the ion exchange method. The glass surface is then covered with a thin uniform optical layer with a high refractive index. The thickness of this layer is less than the cut off thickness for the used wavelength. The wave propagation is therefore possible in the gradient area only. The homogeneous sensitivity of such waveguides is much greater than in case of single-mode waveguides without a uniform layer. The paper presents the calculations of homogeneous sensitivity for single-mode waveguides of the rib type, the inverted rib waveguides and the gradient waveguides. The use of single-mode inverted rib waveguides in the design of the planar interferometer in the Young configuration was proposed.

Rogozi?ski, R.; Tyszkiewicz, C.; Karasi?ski, P.

2014-05-01

63

Babel Fortran 2003 Binding for Structured Data Types  

Energy Technology Data Exchange (ETDEWEB)

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.

Muszala, S; Epperly, T; Wang, N

2008-05-02

64

The Three-Dimensional Structural Basis of Type II Hyperprolinemia  

Energy Technology Data Exchange (ETDEWEB)

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.

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

2012-08-31

65

[Studies on a new type structure OELD with interinserting interface].  

Science.gov (United States)

A new type organic electroluminescent device with interinserting interface was fabricated. The basic structure of the device is ITO/NPB/Alq3/Al. By tailor-made template, the two interinserting interfaces were fabricated with NPB/Alq3 and Alq3/Al, respectively. The charge distribution on the interface and the electric field distribution in the organic layer were changed by introducing interinserting interfaces, thus the electron injection was improved, and the balance of the number of the electrons and holes at the interface was obtained. Therefore, the formation probability of exciton was enhanced and the leakage current was reduced. Compared to the traditional two-layer structure devices, the interinserting structure device has lower turn-on voltage and higher luminous efficiency. The driving-voltage of the interinserting structure OELD decreased while the brightness increased with the increase in the number of the interinsertion. As the current density increased, all the devices with interinserting interface showed high optical-electrical stability. The turn-on voltage of the device e is 3 V, and was made using the three slots template. At the current density of 54 mA x cm(-2), the device e gets its maximum efficiency, which is 34% higher than the traditional structure device a. PMID:20210139

Zhang, Zhi-Qiang; Hao, Yu-Ying; Meng, Wei-Xin; Fan, Wen-Hao; Wang, Hua; Xu, Bing-She

2009-12-01

66

The Structure of Carbon Detonation in Type Ia Supernovae  

Science.gov (United States)

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.

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

67

Moduli of Flat Conformal Structures of Hyperbolic Type  

OpenAIRE

To each flat conformal structure (FCS) of hyperbolic type in the sense of Kulkarni-Pinkall, we associate, for all $\\theta\\in[(n-1)\\pi/2,n\\pi/2[$ and for all $r>\\opTan(\\theta/n)$ a unique immersed hypersurface $\\Sigma_{r,\\theta}=(M,i_{r,\\theta})$ in $\\Bbb{H}^{n+1}$ of constant $\\theta$-special Lagrangian curvature equal to $r$. We show that these hypersurfaces smoothly approximate the boundary of the canonical hyperbolic end associated to the FCS by Kulkarni and Pinkall and t...

Smith, Graham

2008-01-01

68

New germanide superconductors with the type-I clathrate type structure  

International Nuclear Information System (INIS)

Highlights: •We discovered that the new germanide superconductors of A8(Al,Ge)46 (A = Rb, Cs). •The superconducting transition temperature is confirmed at around 3.6 K for A = Rb and 4 K for A = Cs. •The M–H curve at 1.8 K shows that the Rb8(Al,Ge)46 belongs to a type-II superconductor. -- Abstract: We discovered that the new germanide superconductors of A8(Al,Ge)46 (A = Rb, Cs). A8(Al,Ge)46 have the type-I clathrate type structure (cubic, space group: Pm3¯n (No. 223)). The superconducting transition temperature is confirmed at around 3.6 K for Rb8(Al0.4Ge0.6)46 and 4 K for Cs8(Al0.4Ge0.6)46, respectively. The lattice constants of these compounds are estimated to be a = 1.082(6) nm for Rb8(Al0.4Ge0.6)46 and a = 1.087(8) nm for Cs8(Al0.4Ge0.6)46. The M–H curve at 1.8 K shows that the Rb8(Al0.4Ge0.6)46 is categorized to be a conventional type-II superconductor. The superconducting parameters of Rb8(Al0.4Ge0.6)46 are determined using the thermodynamic data and Ginzburg–Landau relations

69

3D dynamic fluid structure coupling analysis of pool type LMFBR structures by substructuring method  

International Nuclear Information System (INIS)

A calculation method to take into account 3D geometry of shells and fluid structure interaction in pool type FBR structures is described in this paper. It is based on substructuring technique and substructures are defined by their natural modes. Application to the seismic behaviour of a reactor similar to SPX1 is made and the results of this 3D calculation are compared to those calculated by 2D model

70

Structural and Magmatic Evolution of Atlantic Type Rifted Margins  

Science.gov (United States)

The increasing number of high quality reflection and refraction seismic surveys and drill hole data in Atlantic type rifted margins show a divergent style of margin architecture and evolution in which quantity and distribution of syn-rift magmatism and fault structures are the most variable features. These observations led to an oversimplified classification of rifted margins as either volcanic or non-volcanic. Although this simple concept may lead to the idea that margins evolve either under the presence or absence of magma, the available data show that rifted margins are more complex and cannot be characterized based on the volume of observed magma alone. Indeed so called "non-volcanic" margins are not necessarily amagmatic, as shown by the results of ODP drilling along the Iberia-Newfoundland rifted margins. On the other hand, magma-rich margins, such as the Norwegian rifted margins, show evidence for hyper-extended crust, suggesting that there is more deformation before magma emplacement as previously proposed. This leads to the question about how magmatic and tectonic processes are interacting before, during and after continental breakup. In my presentation I will review results from the South and North Atlantic and will discuss the structural and magmatic evolution of so called magma-rich and magma-poor rifted margins. I will show that the commonly proposed end-member type margins, i.e. "non-magmatic" and "non-tectonic" margins do not exist and that rifted margins show a more complex poly-phase tectonic and magmatic evolution as previously suggested. However, it remains unclear whether decompression melting is the driving force, or rather the consequence of extension. In my presentation I will discuss to what extent variable amounts of magma may control the evolution and timing of continental breakup and control the architecture of Atlantic type rifted margins.

Manatschal, G.

2011-12-01

71

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

International Nuclear Information System (INIS)

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)

72

Structural trends in off stoichiometric chalcopyrite type compound semiconductors  

International Nuclear Information System (INIS)

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.

73

Structural Characterization of Novel Pseudomonas aeruginosa Type IV Pilins  

Energy Technology Data Exchange (ETDEWEB)

Pseudomonas aeruginosa type IV pili, composed of PilA subunits, are used for attachment and twitching motility on surfaces. P. aeruginosa strains express one of five phylogenetically distinct PilA proteins, four of which are associated with accessory proteins that are involved either in pilin posttranslational modification or in modulation of pilus retraction dynamics. Full understanding of pilin diversity is crucial for the development of a broadly protective pilus-based vaccine. Here, we report the 1.6-{angstrom} X-ray crystal structure of an N-terminally truncated form of the novel PilA from strain Pa110594 (group V), which represents the first non-group II pilin structure solved. Although it maintains the typical T4a pilin fold, with a long N-terminal {alpha}-helix and four-stranded antiparallel {beta}-sheet connected to the C-terminus by a disulfide-bonded loop, the presence of an extra helix in the {alpha}{beta}-loop and a disulfide-bonded loop with helical character gives the structure T4b pilin characteristics. Despite the presence of T4b features, the structure of PilA from strain Pa110594 is most similar to the Neisseria gonorrhoeae pilin and is also predicted to assemble into a fiber similar to the GC pilus, based on our comparative pilus modeling. Interactions between surface-exposed areas of the pilin are suggested to contribute to pilus fiber stability. The non-synonymous sequence changes between group III and V pilins are clustered in the same surface-exposed areas, possibly having an effect on accessory protein interactions. However, based on our high-confidence model of group III PilA{sub PA14}, compensatory changes allow for maintenance of a similar shape.

Nguyen, Y.; Jackson, S; Aidoo, F; Junop, M; Burrows, L

2010-01-01

74

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  

International Nuclear Information System (INIS)

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)

75

Electronic structure of p type Delta doped systems  

International Nuclear Information System (INIS)

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)

76

Gradient type optimization methods for electronic structure calculations  

CERN Document Server

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...

Zhang, Xin; Wen, Zaiwen; Zhou, Aihui

2013-01-01

77

Magnetic resonances in perovskite-type layer structures  

International Nuclear Information System (INIS)

We have studied the q = 0 magnetic excitations of the perovskite-type layer structures A2MnCl4 with A = Rb, Csub(n)Hsub(2n+1)NH3 (n = 1,2,3), and NH3(CH2)sub(m)NH3MnCl4 (m = 2,4,5) in the antiferromagnetic and in the spin flop regime by means of magnetic resonance in the mm-wave range (30-130 GHz) and microwave range (9.2 GHz). The length of the organic molecules determines the separation of the MnCl6 octahedra. With increasing separation the Neel temperature and the antiferromagnetic resonance frequency decrease, which mainly originates from a decrease of the anisotropy field. (orig.)

78

New germanide superconductors with the type-I clathrate type structure  

Energy Technology Data Exchange (ETDEWEB)

Highlights: •We discovered that the new germanide superconductors of A{sub 8}(Al,Ge){sub 46} (A = Rb, Cs). •The superconducting transition temperature is confirmed at around 3.6 K for A = Rb and 4 K for A = Cs. •The M–H curve at 1.8 K shows that the Rb{sub 8}(Al,Ge){sub 46} belongs to a type-II superconductor. -- Abstract: We discovered that the new germanide superconductors of A{sub 8}(Al,Ge){sub 46} (A = Rb, Cs). A{sub 8}(Al,Ge){sub 46} have the type-I clathrate type structure (cubic, space group: Pm3{sup ¯}n (No. 223)). The superconducting transition temperature is confirmed at around 3.6 K for Rb{sub 8}(Al{sub 0.4}Ge{sub 0.6}){sub 46} and 4 K for Cs{sub 8}(Al{sub 0.4}Ge{sub 0.6}){sub 46}, respectively. The lattice constants of these compounds are estimated to be a = 1.082(6) nm for Rb{sub 8}(Al{sub 0.4}Ge{sub 0.6}){sub 46} and a = 1.087(8) nm for Cs{sub 8}(Al{sub 0.4}Ge{sub 0.6}){sub 46}. The M–H curve at 1.8 K shows that the Rb{sub 8}(Al{sub 0.4}Ge{sub 0.6}){sub 46} is categorized to be a conventional type-II superconductor. The superconducting parameters of Rb{sub 8}(Al{sub 0.4}Ge{sub 0.6}){sub 46} are determined using the thermodynamic data and Ginzburg–Landau relations.

Ipponjima, T., E-mail: ipponjima@phys.aoyama.ac.jp [Department of Physics and Mathematics, Aoyama-Gakuin University, 5-10-1 Fuchinobe, Sagamihara-shi, Kanagawa 252-5258 (Japan); Kawashima, K.; Miyazaki, S.; Hyakumura, D. [Department of Physics and Mathematics, Aoyama-Gakuin University, 5-10-1 Fuchinobe, Sagamihara-shi, Kanagawa 252-5258 (Japan); Yoshikawa, M. [IMRA Material Co. Ltd., 2-1 Asahicho, Kariya, Aichi 448-0032 (Japan); Akimitsu, J. [Department of Physics and Mathematics, Aoyama-Gakuin University, 5-10-1 Fuchinobe, Sagamihara-shi, Kanagawa 252-5258 (Japan)

2013-11-15

79

Perovskite-type oxides - Oxygen electrocatalysis and bulk structure  

Science.gov (United States)

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.

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

1988-01-01

80

Structural investigations on native collagen type I fibrils using AFM  

International Nuclear Information System (INIS)

This study was carried out to determine the elastic properties of single collagen type I fibrils with the use of atomic force microscopy (AFM). Native collagen fibrils were formed by self-assembly in vitro characterized with the AFM. To confirm the inner assembly of the collagen fibrils, the AFM was used as a microdissection tool. Native collagen type I fibrils were dissected and the inner core uncovered. To determine the elastic properties of collagen fibrils the tip of the AFM was used as a nanoindentor by recording force-displacement curves. Measurements were done on the outer shell and in the core of the fibril. The structural investigations revealed the banding of the shell also in the core of native collagen fibrils. Nanoindentation experiments showed the same Young's modulus on the shell as well as in the core of the investigated native collagen fibrils. In addition, the measurements indicate a higher adhesion in the core of the collagen fibrils compared to the shell

81

Charge releasing type radiation detector using MIS structure  

International Nuclear Information System (INIS)

One of the shortcomings of superconducting radiation detectors is their small active volumes: the energy deposited by X-ray is easy to escape from the active volume and causes degradation of energy resolution. A Si radiation detector which operates at 1 K with high energy resolution and a large sensitive volume was investigated. In this detector, electrons/holes to donors/acceptors need to supply from the outside of the detector. A carrier releasing type radiation detector (CRD) was fabricated with p-type silicon which contains boron impurities. As a carrier supplying method in the CRD, metal-insulator-semiconductor (MIS) structure was proposed as a detector and the MIS devices was fabricated. The energy resolution of the CRD was estimated 7.4 eV for 6 keV X-ray. For supplying holes to boron in a CRD made of p-Si, the MIS device should behave as capacitor with applying bias voltage. This MIS device showed the behavior of capacitor at room temperature. At 4.2 K, however, any field effect in this MIS device could not be observed due to the change of ohmic electrode to Schottky electrode at low temperature. To prevent an ohmic electrode turning to Schottky one, it needs to dope boron in p-Si beneath the ohmic electrodes. (M. Suetake)

82

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

Energy Technology Data Exchange (ETDEWEB)

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)

Adachi, Takafumi (Institute for Molecular Science, Okazaki, Aichi (Japan)); Shirotani, Ichimin; Shimomura, Osamu

1999-04-01

83

Altered nuclear structure in myotonic dystrophy type 1-derived fibroblasts.  

Science.gov (United States)

Myotonic dystrophy type 1 (DM1) is a multisystem genetic disorder caused by a triplet nucleotide repeat expansion in the 3' untranslated region of the Dystrophia Myotonica-Protein Kinase (DMPK) gene. DMPK gene transcripts containing CUG expanded repeats accumulate in nuclear foci and ultimately cause altered splicing/gene expression of numerous secondary genes. The study of primary cell cultures derived from patients with DM1 has allowed the identification and further characterization of molecular mechanisms underlying the pathology in the natural context of the disease. In this study we show for the first time impaired nuclear structure in fibroblasts of DM1 patients. DM1-derived fibroblasts exhibited altered localization of the nuclear envelope (NE) proteins emerin and lamins A/C and B1 with concomitant increased size and altered shape of nuclei. Abnormal NE organization is more common in DM1 fibroblasts containing abundant nuclear foci, implying expression of the expanded RNA as determinant of nuclear defects. That transient expression of the DMPK 3' UTR containing 960 CTG but not with the 3' UTR lacking CTG repeats is sufficient to generate NE disruption in normal fibroblasts confirms the direct impact of mutant RNA on NE architecture. We also evidence nucleoli distortion in DM1 fibroblasts by immunostaining of the nucleolar protein fibrillarin, implying a broader effect of the mutant RNA on nuclear structure. In summary, these findings reveal that NE disruption, a hallmark of laminopathy disorders, is a novel characteristic of DM1. PMID:25307018

Rodríguez, R; Hernández-Hernández, O; Magaña, J J; González-Ramírez, R; García-López, E S; Cisneros, B

2015-02-01

84

Type IIA orientifolds on SU(2)-structure manifolds  

Energy Technology Data Exchange (ETDEWEB)

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.)

Danckaert, Thomas

2010-11-15

85

Structural integrity test of helical-type intermediate heat exchanger  

International Nuclear Information System (INIS)

An intermediate heat exchanger (IHX) for the High Temperature Engineering Test Reactor (HTTR) is an important component of the cooling system and it is important to confirm the structural integrity. Particularly, a connecting tube would be subjected to thermal stress caused by the difference of thermal expansion and temperature between the manifold and the helical tube and is under severe design condition which is used in over 900degC in normal operation. The structural integrity test of an in-scale model consisted of the manifold and the lower connecting tube of the IHX for the HTTR was carried out under accelerated condition of the normal operation. From the present study, the crack was observed to have grown through the wall of the tube in two heat transfer tubes. The coil portion and the lower elbow portion of the heat transfer tube slightly hung down and the lower connecting tube was inclined. Prediction of fracture life by using the elastic-creep analysis which used Garofalo type of the creep constitutive equation and the time fraction rule was very conservative as compared with the experimental fracture life. (author)

86

Structural trends in off stoichiometric chalcopyrite type compound semiconductors  

Energy Technology Data Exchange (ETDEWEB)

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.

Stephan, Christiane

2011-03-15

87

GOES-R User Data Types and Structure  

Science.gov (United States)

GOES-R meteorological data is provided to the operational and science user community through four main distribution mechanisms. The GOES-R Ground Segment (GS) generates a set of Level 1b (L1b) data from each of the six primary satellite instruments and formats the data into a direct broadcast stream known as GOES Rebroadcast (GRB). Terrestrially, cloud and moisture imagery data is provided to forecasters at the National Weather Service (NWS) through a direct interface to the Advanced Weather Interactive Processing System (AWIPS). A secondary pathway for the user community to receive data terrestrially is via NOAA's Environmental Satellite Processing and Distribution System (ESPDS) Product Distribution and Access (PDA) system. The ESPDS PDA will service the NWS and other meteorological users through a data portal, which provides both a subscription service and an ad hoc query capability. Finally, GOES-R data is made available to NOAA's Comprehensive Large Array-Data Stewardship System (CLASS) for long-term archive. CLASS data includes the L1b and L2+ products sent to PDA, along with the Level 0 data used to create these products, and other data used for product generation and processing. This session will provide a summary description of the data types and formats associated with each of the four primary distribution pathways for user data from GOES-R. It will discuss the resources that are being developed by GOES-R to document the data structures and formats. It will also provide a brief introduction to the types of metadata associated with each of the primary data flows.

Royle, A. W.

2012-12-01

88

Mass Structure of Axial Vector Types of Leptons and Fields  

CERN Document Server

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...

Sharafiddinov, Rasulkhozha S

2011-01-01

89

New types of nonlinear optical materials - Li3VO4- and Li3PO4-type structures  

Science.gov (United States)

Li3VO4 and LI3PO4 types of structure crystals are found as new types of nonlinear optical materials for second-harmonic generation. Their lattices are formed of only the MO4 oxygen tetrahedra, being different from other typical nonlinear optical materials that have been developed previously.

Sakata, Shin'ichi; Fujii, Itsuhiro

1991-08-01

90

Observation of type-I and type-II excitons in strained Si/SiGe quantum-well structures  

OpenAIRE

The authors report photoluminescence (PL) measurement on a series of SiSiGe quantum-well structures that had different internal strain distributions. When each sample was placed in a high magnetic field, the field-dependent energy shift of the relevant PL peaks revealed either type-I or type-II exciton formation depending on the strain distribution. This observation is in agreement with theoretical modeling. The present investigation shows that type-I band alignment-desired for electrolumines...

Wang, Ky; Huang, Wp; Cheng, Hh; Sun, G.; Soref, Ra; Nicholas, Rj; Suen, Yw

2007-01-01

91

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

International Nuclear Information System (INIS)

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(?(t)) prolongation structure for an inhomogeneous equation of the reaction-diffusion type and give the corresponding AKNS-type equations and the Baecklund transformation

92

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

Science.gov (United States)

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.

Eliziario Nunes, Sayonara; Wang, Chun-Hai; So, Karwei; Evans, John S. O.; Evans, Ivana Radosavljevi?

2015-02-01

93

Fine structure analysis of type-specific and type-common antigenic sites of herpes simplex virus glycoprotein D.  

OpenAIRE

The fine structure of the antigenic determinants of herpes simplex virus type 1 and 2 glycoprotein D (gD) was analyzed to determine whether structural differences underlie the differential immunogenicity of these glycoproteins. A region common to herpes simplex virus type 1 and 2 gD (amino acid residues 11 to 19) and two sites specific for herpes simplex virus type 2 gD (one determined by proline at position 7, the other determined by asparagine at position 21) were localized within the N-ter...

Dietzschold, B.; Eisenberg, R. J.; Ponce Leon, M.; Golub, E.; Hudecz, F.; Varrichio, A.; Cohen, G. H.

1984-01-01

94

Well-formedness and typing rules for UML Composite Structures  

OpenAIRE

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 specifi...

Dragomir, Iulia; Ober, Iulian

2010-01-01

95

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

OpenAIRE

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...

Pietruszka, Rafal; Witkowski, Bartlomiej Slawomir; Luka, Grzegorz; Wachnicki, Lukasz; Gieraltowska, Sylwia; Kopalko, Krzysztof; Zielony, Eunika; Bieganski, Piotr; Placzek-popko, Ewa; Godlewski, Marek

2014-01-01

96

Quadrant-type X-band single-cell structure for high gradient tests  

International Nuclear Information System (INIS)

We are building a new high-gradient X-band (11.424 GHz) testbench, called “Shield-B,” for basic studies to establish a acceleration technology with 100MV/m or higher, where various single-cell structures are to be tested. We focus on quadrant-type structures, on which no surface currents associated with magnetic fields flow across cell-to-cell junctions unlike disk-type structures. In this study, we propose a quadrant-type X-band single-cell structure with a heavy damped structure by waveguides, overcoming its issues. (author)

97

A New Type of Center Data Structure in Cloud Computing  

Directory of Open Access Journals (Sweden)

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 center’s 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.

Guo Xiaohui

2014-01-01

98

Cage structure materials for n-type transparent conducting oxides  

Science.gov (United States)

The transport properties of mayenite-based materials, Ca12Al 14O33, were investigated. Systems studied included H-doped/UV-irradiated Ca12Al14O33, Ca(12- x)MgxAl14O 33 (x = 0.1, 0.3, 0.5, 0.8, 1) and Ca12Al(14- x)Six O33+x2 (x = 1, 2, 3, 4). The as-prepared Ca12Al14O 33 exhibited a room temperature electronic conductivity on the order of 10-10 S/cm, and a high temperature (600°C) ionic conductivity approximately an order of magnitude less than that of yttria-stabilized zirconia. After H-doping/UV-irradiation Ca12Al14O33 displayed an electronic conductivity of 0.3 S/cm at room temperature rising reversibly to 1 S/cm at ˜130°. Beyond this temperature hydrogen loss is evident and with it the carrier concentration decreases. Below room temperature the system exhibits a variable range hopping and a small polaron hopping above room temperature. H-treated/UV-irradiated Mg-substituted compounds present inferior electrical properties compared to Ca12Al14O 33, with conductivities in the range of 0.15-0.28 S/cm at room temperature. Magnesium is suggested to be responsible for the overall decrease in conductivity, as theoretical calculations suggest that it acts as a blocking agent. On the other hand, the proton-implanted/UV-irradiated Ca12Al(14-x)Si x O33+x2 shows an increase in conductivity, consistent with the aliovalent substitution. Conductivities of 0.68 S/cm were found for the higher Si-substitution level (in H-implanted specimens) suggesting that the amount of free oxygen ions inside the structural cavities plays a significant role in determining the electrical properties of the compound. Results are in good agreement with density functional calculations performed on all these systems. The highly reduced [Ca24Al28O62] +4+4e- system presents a wide range of conductivities dependent on the reduction time. The maximum value obtained was 1400 S/cm for Ca12Al14O33 reduced in the presence of titanium shot for 4 days of treatment. A reversal in the sign of the thermopower was observed for the high conductivity samples. The temperature dependance of the conductivity shows degenerate behavior above room temperature, and a linear relation between the resistivity and temperature below room temperature. This degenerate behavior suggests an insulator-to-metal conversion, however, it can also be explained by the small polaron mechanism observed for the H-treated/UV-activated mayenite-based samples. Ultimately, mobility data will define the type of mechanism governing this compound's behavior.

Bertoni, Mariana Ines

99

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

OpenAIRE

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 origi...

Igor Zelenko

2009-01-01

100

A New Type of Center Data Structure in Cloud Computing  

OpenAIRE

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...

Guo Xiaohui; Wei Jian Yu; Wang Beibei; Liyongqing

2014-01-01

101

Structural and magnetic properties of Fe-Cr-Al alloys with DO3-type structure  

International Nuclear Information System (INIS)

X-ray, neutron, magnetization and Moessbauer studies in the temperature range 10-300 K are reported for Fe3-xCrxAl system with x3-type structure is maintained in the range of Cr concentration studied. It was found that Cr atoms occupy preferentially B-sites and the lattice constant decreases with increasing concentration of chromium. The magnetic moment of chromium is small and diminishes the value of neighbouring iron atoms by about 0.1 ?B per Cr atom. The magnetic moments of iron at (A, C) and B sites were estimated to be 1.54 (22), 2.58 (22), 1.51 (27) and 2.32 (14) ?B for T=10 and 300 K, respectively. The magnetic moment of iron decreases by 0.37 (10) and 0.26 (6) ?B at 10 K and T=300 K, respectively, if one aluminium atom is found as a nearest neighbour of iron. (orig.)

102

Structures of the Mating-Type Loci of Cordyceps takaomontana  

OpenAIRE

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.

Yokoyama, Eiji; Yamagishi, Kenzo; Hara, Akira

2003-01-01

103

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

International Nuclear Information System (INIS)

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.)

104

Well-formedness and typing rules for UML Composite Structures  

CERN Document Server

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.

Dragomir, Iulia

2010-01-01

105

The on axis coupled structure type RF gun  

International Nuclear Information System (INIS)

The fundamental design of this newly developed RF gun with a thermionic cathode is the ?/2 mode standing wave structure. It has two accelerating cells and a coupling cell located on the beam axis, a so-called on axis coupled structure (OCS). This structure offers a stable operation for high beam current, owing to high group velocity and wide bandwidth. It is important to reduce damage onto the cathode caused by back bombardment, especially for long macropulse operation, such as in an FEL injector. Back bombardment, as well as output beam profile was simulated by using the electromagnetic field analytical codes 'EMSYS'(2D) and 'MAFIA'(3D). The cavity shape was optimized to reduce back bombardment power without sacrificing beam emittance

106

The on axis coupled structure type RF gun  

Science.gov (United States)

The fundamental design of this newly developed RF gun with a thermionic cathode is the ?/2 mode standing wave structure. It has two accelerating cells and a coupling cell located on the beam axis, a so-called on axis coupled structure (OCS). This structure offers a stable operation for high beam current, owing to high group velocity and wide bandwidth. It is important to reduce damage onto the cathode caused by back bombardment, especially for long macropulse operation, such as in an FEL injector. Back bombardment, as well as output beam profile was simulated by using the electromagnetic field analytical codes 'EMSYS'(2D) and 'MAFIA'(3D). The cavity shape was optimized to reduce back bombardment power without sacrificing beam emittance.

Oda, Fumihiko; Yokoyama, Minoru; Nakayama, Akihiro; Tanabe, Eiji

1999-06-01

107

The on axis coupled structure type RF gun  

CERN Document Server

The fundamental design of this newly developed RF gun with a thermionic cathode is the pi/2 mode standing wave structure. It has two accelerating cells and a coupling cell located on the beam axis, a so-called on axis coupled structure (OCS). This structure offers a stable operation for high beam current, owing to high group velocity and wide bandwidth. It is important to reduce damage onto the cathode caused by back bombardment, especially for long macropulse operation, such as in an FEL injector. Back bombardment, as well as output beam profile was simulated by using the electromagnetic field analytical codes 'EMSYS'(2D) and 'MAFIA'(3D). The cavity shape was optimized to reduce back bombardment power without sacrificing beam emittance.

Oda, F; Nakayama, A; Tanabe, E

1999-01-01

108

Realization of body centered tetragonal, ?-tin and diamond type structures using five beam interference  

Science.gov (United States)

A five beam interference configuration, with one central circularly polarized beam and four linearly polarized side beams incident at equal tilt angles in two orthogonal planes, is investigated for realization of three dimensional periodic structures. It was observed that when the two pairs of linearly polarized waves are TE-TM polarized, dumb-bell shaped pattern and body centered tetragonal lattice structures could be realized. And when all the four linearly polarized waves are TE polarized, with circularly polarized central beam, woodpile type structures and ?-tin type structure could be formed. The obtained ?-tin type structure was found to get transformed into diamond cubic type structure when the angle of incidence was increased to an optimum value.

Sidharthan, Raghuraman; Kumar, Manish; Joseph, Joby; Murukeshan, Vadakke Matham

2014-07-01

109

Electronic structure and physical properties of Ba8Ga16Sn30 clathrates with type-I and type-VIII structure  

International Nuclear Information System (INIS)

A joint experimental and theoretical investigation is performed for Ba-Sn-Ga type-I and type-VIII clathrates. The type-I sample shows a semiconductor characteristic which is accords with the first principle simulation. The type-I clathrate follows Zintl-like behaviour and the semiconducting gap is about 0.6 eV which is agreement with measurement. For the type-VIII clathrate, the simulation shows that a complicated band structure around Fermi level. For the density of states, a peak appears in the fundamental gap, which corresponds to hybridization of Ba bonding orbitals and Sn(Ga) network. A superconducting transition at TC=4 K is observed, which is close to the TC of Sn. An alternative explanation is superconductivity in type-VIII sample arises from increase of electronic density of states around Fermi level EF in the BCS theoretical frame

110

Internal structure of ribosomes using different types of emission  

Energy Technology Data Exchange (ETDEWEB)

A review is made of the experimental results obtained by the author and co-workers on the study of the structural organization of the RNA and the protein in ribosomes by the method of joint use of light, x ray and neutron scattering and by the method of contrast variation in neutron scattering. It is suggested that almost all ribosomal proteins are usual globular proteins recognizing the specific sequence of RNA on the periphery of the particles, and, hence, that the formation of functional centers on the ribosome analogous to the formation of functional centers of other complex proteins with a quaternary structure.

Serdiuk, I.N.

1979-01-01

111

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

Directory of Open Access Journals (Sweden)

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.

Igor Zelenko

2009-10-01

112

On the structure of regular $B_2$-type crystals  

CERN Document Server

For simply-laced Kac-Moody algebras $\\frak g$, Stembridge (2003) proposed a `local' axiomatization of crystal graphs of representations of $U_q(\\frak g)$. In this paper we propose axioms for edge-2-colored graphs which characterize the crystals of integrable representations of $U_q(sp(4))$, regular crystal graphs of $B_2$-type. An edge-colored directed graph which obeys our Axioms (K0)--(K5) is called an R-{\\em graph} (for brevity), and our main result is that the regular crystals of $B_2$-type are R-graphs and vice versa. We give a direct combinatorial construction for the crystals in question. On this way we introduce a new, so-called {\\em crossing model}, which does not exploit Young tableaux. This combinatorial model consists of a two-component graph of a rather simple form and of a certain set of integer-valued functions on its vertices.

Danilov, V I; Koshevoy, G A

2006-01-01

113

Study on fluid-structure interaction of pool-type LMFBR reactor vessel  

International Nuclear Information System (INIS)

The pool type LMFBR reactor vessel contains many structures and a large amount of liquid sodium in it, in addition to being thin shell structure. Therefore, the fluid-structure interaction will become more predominant, and then should be considered for the seismic design of the pool type LMFBR. In this study, the authors investigated the fluid-structure interaction problems of the reactor vessel which has the bottom support arrangement as the core support system, in addition to the sloshing characteristics in the reactor vessel. The experimental results and the analytical results by FEM which took into account the interaction between fluid and structures were presented here

114

Stability of elongated and compact types of structures in SiO2 nanoparticles  

Science.gov (United States)

The stability of elongated and compact types of structure in SiO2 nanoparticles was studied using plane-wave density-functional theory. Calculations were carried out on small SiO2 nanoparticles with 12-46 molecules. It is found that elongated structures are favored for particles consisting of less than 38 molecules of SiO2. In contrast, nanoparticles containing more than 38 molecules favor the compact (spherical) structures. This indicates that the structural transition from elongated to compact structures occurs at a size of around 38 molecules. Several low-energy isomers of elongated types of structure for different sizes of SiO2 nanoparticles have been characterized. The nanoparticles are found to consist of various types of silica rings (four-, five-, and/or six-membered rings), similar to vitreous silica in bulk. The elongated structures consist of rather regular and symmetric silica rings, while the compact structures consist of considerably distorted silica rings. In particular, the elongated structures consisting of five-membered rings with the top and bottom layers being connected in the form of four-membered rings are relatively stable, leading to very regular and symmetric structures. The elongated types of structures might be proposed for the atomic structures of silica nanowires.

Song, Jakyoung; Choi, Mansoo

2002-05-01

115

Structural homologies among type I restriction-modification systems.  

OpenAIRE

Structural homologies among different restriction systems of Escherichia coli and several Salmonella species have been investigated by immunological methods using antibodies prepared against two subunits of the E. coli K12 restriction enzyme, and by DNA hybridization experiments using different fragments of the E. coli K12 hsd genes as probes. The results with both techniques show a strong homology between the E. coli K12 and B restriction-modification systems, weaker but nevertheless marked ...

Murray, N. E.; Gough, J. A.; Suri, B.; Bickle, T. A.

1982-01-01

116

Structural studies of different types of ferroelectric liquid crystalline substances.  

Czech Academy of Sciences Publication Activity Database

Ro?. 35, ?. 1 (2011), s. 3-13. ISSN 1450-7404 R&D Projects: GA AV ?R IAA100100911; GA AV ?R(CZ) GA202/09/0047; GA ?R(CZ) GAP204/11/0723 Grant ostatní: RFASI(RU) 02.740.11.5166 Institutional research plan: CEZ:AV0Z10100520 Keywords : ferroelectric liquid crystals * phase transition * structure of liquid crystalline phases * molecular parameters Subject RIV: BM - Solid Matter Physics ; Magnetism

Obadovi?, D.Ž.; Stojanovi?, M.; Bubnov, Alexej; Éber, N.; Cvetinov, M.; Vajda, A.

2011-01-01

117

Types of personality motivation structure of women who are acquiring higher education in psychology  

Directory of Open Access Journals (Sweden)

Full Text Available The article deals with the results of empirical research on the types of personality motivation structure of women who are acquiring higher education in psychology. Two types have been singled out: expressive and impulsive. The expressive type comprises two components: ideal motivation aimed at life necessities, general activity and social utility, and real motivation aimed at comfort, social status and communication. In the structure of the impulsive type there are three components: real motivation aimed at life necessities, social status, general activity and social utility; real motivation aimed at communication and comfort; creativity motivation aimed at self-development and creative activity. Women belonging to the expressive type of personality motivation structure have more positive self-attitude and a higher level of psychological well-being than women belonging to the impulsive type.

TETIANA PARTYKO

2013-09-01

118

Understanding the structural scaling relations of early-type galaxies  

Science.gov (United States)

We use a large suite of hydrodynamical simulations of binary galaxy mergers to construct and calibrate a physical prescription for computing the effective radii and velocity dispersions of spheroids. We implement this prescription within a semi-analytic model embedded in merger trees extracted from the Bolshoi ? cold dark matter N-body simulation, accounting for spheroid growth via major and minor mergers and disc instabilities. We find that without disc instabilities, our model does not predict sufficient numbers of intermediate-mass early-type galaxies in the local Universe. Spheroids also form earlier in models with spheroid growth via disc instabilities. Our model correctly predicts the normalization, slope, and scatter of the low-redshift size-mass and Fundamental Plane relations for early-type galaxies. It predicts a degree of curvature in the Faber-Jackson relation that is not seen in local observations, but this could be alleviated if higher mass spheroids have more bottom-heavy initial mass functions. The model also correctly predicts the observed strong evolution of the size-mass relation for spheroids out to higher redshifts, as well as the slower evolution in the normalization of the Faber-Jackson relation. We emphasize that these are genuine predictions of the model since it was tuned to match hydrodynamical simulations and not these observations.

Porter, L. A.; Somerville, R. S.; Primack, J. R.; Johansson, P. H.

2014-10-01

119

Understanding the Structural Scaling Relations of Early-Type Galaxies  

CERN Document Server

We use a large suite of hydrodynamical simulations of binary galaxy mergers to construct and calibrate a physical prescription for computing the effective radii and velocity dispersions of spheroids. We implement this prescription within a semi-analytic model embedded in merger trees extracted from the Bolshoi Lambda-CDM N-body simulation, accounting for spheroid growth via major and minor mergers as well as disk instabilities. We find that without disk instabilities, our model does not predict sufficient numbers of intermediate mass early-type galaxies in the local universe. Spheroids also form earlier in models with spheroid growth via disk instabilities. Our model correctly predicts the normalization, slope, and scatter of the low-redshift size-mass and Fundamental Plane relations for early type galaxies. It predicts a degree of curvature in the Faber-Jackson relation that is not seen in local observations, but this could be alleviated if higher mass spheroids have more bottom-heavy initial mass functions....

Porter, Lauren A; Primack, Joel R; Johansson, Peter H

2014-01-01

120

Type I and type II fatty acid biosynthesis in Eimeria tenella : enoyl reductase activity and structure  

OpenAIRE

Apicomplexan parasites of the genus Eimeria are the major causative agent of avian coccidiosis, leading to high economic losses in the poultry industry. Recent results show that Eimeria tenella harbours an apicoplast organelle, and that a key biosynthetic enzyme, enoyl reductase, is located in this organelle. In related parasites, enoyl reductase is one component of a type II fatty acid synthase (FAS) and has proven to be an attractive target for antimicrobial compounds. We cloned and express...

Lu, J. Z.; Muench, S. P.; Allary, M.; Campbell, S.; Roberts, C. W.; Mui, E.; Mcleod, R. L.; Rice, D. W.; Prigge, S. T.

2007-01-01

121

Topology of Type II REases revisited; structural classes and the common conserved core  

Science.gov (United States)

Type II restriction endonucleases (REases) are deoxyribonucleases that cleave DNA sequences with remarkable specificity. Type II REases are highly divergent in sequence as well as in topology, i.e. the connectivity of secondary structure elements. A widely held assumption is that a structural core of five ?-strands flanked by two ?-helices is common to these enzymes. We introduce a systematic procedure to enumerate secondary structure elements in an unambiguous and reproducible way, and use it to analyze the currently available X-ray structures of Type II REases. Based on this analysis, we propose an alternative definition of the core, which we term the ???-core. The ???-core includes the most frequently observed secondary structure elements and is not a sandwich, as it consists of a five-strand ?-sheet and two ?-helices on the same face of the ?-sheet. We use the ???-core connectivity as a basis for grouping the Type II REases into distinct structural classes. In these new structural classes, the connectivity correlates with the angles between the secondary structure elements and with the cleavage patterns of the REases. We show that there exists a substructure of the ???-core, namely a common conserved core, ccc, defined here as one ?-helix and four ?-strands common to all Type II REase of known structure. PMID:17369272

Niv, Masha Y.; Ripoll, Daniel R.; Vila, Jorge A.; Liwo, Adam; Vanamee, Éva S.; Aggarwal, Aneel K.; Weinstein, Harel; Scheraga, Harold A.

2007-01-01

122

Characterization of octupole-type structures in Th221  

Science.gov (United States)

A detailed level scheme for Th221 has been established in an experiment using the O18+207Pb reaction at 96 MeV. The evaporation residues from this fissile system were selected with the HERCULES detector array and residue-gated ? rays were measured with Gammasphere. Three band structures of interlinked, alternating-parity levels are observed, two of which are non-yrast. In addition, several high-lying excitations are found. The yrast band is seen up to spin-parity 37/2- and 39/2+, beyond which a high-spin feeding transition is observed. The non-yrast sequences are interpreted as parity-doublet structures, based on a configuration similar to that of the yrast band in Th223 (K=5/2). The key properties of even-odd nuclei in this mass region [B(E1)/B(E2) and B (M1)/B(E2) ratios, spin alignments, parity splittings] are reviewed.

Reviol, W.; Janssens, R. V. F.; Frauendorf, S.; Sarantites, D. G.; Carpenter, M. P.; Chen, X.; Chiara, C. J.; Hartley, D. J.; Hauschild, K.; Lauritsen, T.; Lopez-Martens, A.; Montero, M.; Pechenaya, O. L.; Seweryniak, D.; Snyder, J. B.; Zhu, S.

2014-10-01

123

Ferroelectric and ferroelastic domains in bronze type tunnel structures  

International Nuclear Information System (INIS)

This brief review serves to illustrate the capabilities of high-resolution electron microscopy (HREM) to reveal fine structures of a surprising variety of microstructural domains. Example include the hierarchy of chaotic states existing in the incommensurate room temperature phase of strontium barium niobate. HREM showed directly nature of the atoms (W,Nb) displacements responsible for the hexagonal component of the superstructures occurring throughout phase transitions of potassium niobium tungstate (PNT). The reciprocal lattice geometry of the commensurate superlattice phase of barium sodium niobate has been determined and a full structural model derived; thus the space group appears to be Im2a with orthorhombic cell parameters a=35.18Aangstroem, b=35.24Aangstroem, c=7.99 Aangstroem. Non-stoichiometric phases of PNT have orthorhombic superstructures and the microdiffraction analysis allowed possible orthorhombic space groups and unit cell parameters to be derived for the three phases. It is suggested that PNT may be considered as an alternative subject for non-linear laser technology. 20 figs., 9 figs

124

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

Science.gov (United States)

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%. PMID:24605282

Pietruszka, Rafal; Witkowski, Bartlomiej Slawomir; Luka, Grzegorz; Wachnicki, Lukasz; Gieraltowska, Sylwia; Kopalko, Krzysztof; Zielony, Eunika; Bieganski, Piotr; Placzek-Popko, Ewa; Godlewski, Marek

2014-01-01

125

Temperature dependent XAFS studies of local atomic structure of the perovskite-type zirconates  

International Nuclear Information System (INIS)

Temperature dependent preedge and extended x-ray absorption fine structure measurements at the Zr K edge for the perovskite-type zirconates PbZr0.515Ti0.485O3 (PZT), PbZrO3 (PZ), and BaZrO3 are performed. To carry out a more accurate study of the weak reconstruction of the local atomic structure we employed a combination of two techniques: (i) analysis of the preedge fine structure, and (ii) analysis of the Fourier transform of the difference between ?(k) functions obtained at different temperatures. A detailed investigation of local atomic structure in the cubic phase for all the crystals is also performed. It is shown that neither the displacive nor the order-disorder model can describe correctly the changes of local atomic structure during phase transitions in PZ and PZT. A spherical model describing the local atomic structure of perovskite-type crystals suffering structural phase transitions is proposed

126

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2010-03-08

127

One-dimensional quantum spin magnetism of the CrVO{sub 4} structure-type  

Energy Technology Data Exchange (ETDEWEB)

In recent years we have investigated and characterized many new and interesting 1D quantum spin systems, as of late we have concentrated on compounds that crystallize in the CrVO{sub 4} structure-type. Here we will present new results for materials that adopt this structure-type, ranging from spin-spiral long-range magnetic order and Multiferrocity to two stage spin-Peierls transitions.

Law, Joseph; Kremer, Reinhard [Max Planck Institute for Solid State Research, D-70569 Stuttgart (Germany)

2012-07-01

128

Experimental investigation on sandwich structure ring-type ultrasonic motor.  

Science.gov (United States)

This paper presents a manufacture method for a sandwich structure Ultrasonic Motor (USM) and experiment. Two pieces of rotor clamped on a stator, and a stainless steel disk-spring is bonded on the hollow rotor disk to provide the press by a nut assembled on the shaft. The stator is made of a double-side Printed-Circuit Board (PCB) which is sawed out the ring in the center and connected on the board with three legs. On each side of the ring surface, there are electrodes connected at the same position via through hole. The three layer drive circuit for sine, cosine, and ground signal is connected on the board through each leg. There are many piezoelectric components (PZT) bonded between two electrodes and fill soldering tin on each electrode. Then PZT is welded on PCB by reflow soldering. Finally, rub the gibbous soldering tin down to the position of PZT surface makes sure the surface contacts with rotor evenly. The welding process can also be completed by Surface Mounted Technology (SMT). A prototype motor is manufactured by this method. Two B03 model shapes of the stator are obtained by the finite element analysis and the optimal frequency of the motor is 56.375 kHz measured by impedance instrument. The theoretical analysis is conducted for the relationship between the revolving speed of the USM and thickness of stator ring, number of the travelling waves, PZT amplitude, frequency and the other parameters. The experiment result shows that the maximum revolving speed is 116 RPM and the maximum torque is 25 N mm, when the actuate voltage is 200 VAC. PMID:25213313

Peng, Taijiang; Shi, Hongyan; Liang, Xiong; Luo, Feng; Wu, Xiaoyu

2015-02-01

129

Zeolite structure type EAB: Crystal structure and mechanism for the topotactic transformation of the Na, TMA form  

Science.gov (United States)

Synthetic zeolite (Na, TMA)-E represents a new structure type designated EAB. Detailed structure analyses based on X-ray powder diffraction data have been carried out at room temperature, 220°C, and 350°C. The silicate framework, having maximum symmetry {P6 3}/{mmc}, consists of parallel 6-rings in ABBACC sequence as opposed to AABAAC in erionite (with which it has mistakenly been identified). Large changes in conformation of the EAB framework precede the transformation of (Na, TMA)-E to a sodalite-type product above 360°C. There are also strong indications for this reaction to be topotactic, whereby only one-twelfth of the original siloxane bridges are broken. Details of an acid-base reaction mechanism proceeding in characteristic loops of the structure are discussed. This process brings about the inversion of one-third of the tetrahedra in the silicate framework. The presence of water appears to be essential in this model-type reaction.

Meier, W. M.; Groner, M.

1981-04-01

130

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

Directory of Open Access Journals (Sweden)

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.

O.R. Nandagopan

2013-07-01

131

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

Directory of Open Access Journals (Sweden)

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

O. R. Nandagopan

2013-07-01

132

On some Hermitian variations of Hodge structure of Calabi-Yau type with real multiplication  

OpenAIRE

We prove that, for every totally real number field E_0, there exists a weight three variation of Hodge structure of Calabi-Yau type defined over the rational numbers with associated endomorphism algebra E_0 such that the unique irreducible factor of Calabi-Yau type of the corresponding real variation of Hodge structure is the canonical real VHS of CY type over the Hermitian symmetric domain II_6, associated to the real group SO^*(12). The main point is a rationality result f...

Friedman, Robert; Laza, Radu

2013-01-01

133

Crystal structure analysis of Scheelite and Zircon type thorium germanates: A neutron diffraction study  

International Nuclear Information System (INIS)

In this communication we report the detailed crystal structure of two polymorphs of ThGeO4 (scheelite and zircon type) by Rietveld refinement of the neutron diffraction data of polycrystalline samples. Both of crystal structures consist of ThO8 (bisdisphenoid) and GeO4 tetrahedra. Scheelite type structure is a meta-stable polymorph and densely packed lattice, with a little larger average bond lengths of Th-O and Ge-O bonds to accommodate better packing. This is responsible for zircon to scheelite transformation under pressure. However, the average anion-anion contact and cation-cation contacts are shorter in scheelite structure compared to the zircon structure, which would causes the meta-stability in the scheelite structure

134

Structure refinement of decagonal Al-Ni-Co, superstructure type I  

OpenAIRE

Abstract The structure of decagonal Al-Ni-Co, superstructure type I (so called Edagawa phase) was refined in the physical space. A statistical approach was used to calculate the structure factor based on the rhombic Penrose This tiling, with tile edge length 12.1 Å, as reference frame. A total number of 691 parameters was refined against 6843 structure amplitudes, merged in Laue group 10/m.

Kuczera, Pawel; Wolny, Janusz; Fleischer, Frank; Steurer, Walter

2010-01-01

135

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2007-09-15

136

The E^3/Z3 orbifold, mirror symmetry, and Hodge structures of Calabi-Yau type  

CERN Document Server

Starting from the K\\"ahler moduli space of the rigid orbifold Z=E^3/\\mathbb{Z}_3 one would expect for the cohomology of the generalized mirror to be a Hodge structure of Calabi-Yau type (1,9,9,1). We show that such a structure arises in a natural way from rational Hodge structures on \\Lambda^3 \\mathbb{K}^6, \\mathbb{K}=\\mathbb{Q}[\\omega], where \\omega is a primitive third root of unity. We do not try to identify an underlying geometry, but we show how special geometry arises in our abstract construction. We also show how such Hodge structure can be recovered as a polarized substructure of a bigger Hodge structure given by the third cohomology group of a six-dimensional Abelian variety of Weil type.

Cacciatori, Sergio Luigi

2012-01-01

137

Life comparative analysis of energy consumption and CO? emissions of different building structural frame types.  

Science.gov (United States)

The objective of this research is to quantitatively measure and compare the environmental load and construction cost of different structural frame types. Construction cost also accounts for the costs of CO? emissions of input materials. The choice of structural frame type is a major consideration in construction, as this element represents about 33% of total building construction costs. In this research, four constructed buildings were analyzed, with these having either reinforced concrete (RC) or steel (S) structures. An input-output framework analysis was used to measure energy consumption and CO? emissions of input materials for each structural frame type. In addition, the CO? emissions cost was measured using the trading price of CO? emissions on the International Commodity Exchange. This research revealed that both energy consumption and CO? emissions were, on average, 26% lower with the RC structure than with the S structure, and the construction costs (including the CO? emissions cost) of the RC structure were about 9.8% lower, compared to the S structure. This research provides insights through which the construction industry will be able to respond to the carbon market, which is expected to continue to grow in the future. PMID:24227998

Kim, Sangyong; Moon, Joon-Ho; Shin, Yoonseok; Kim, Gwang-Hee; Seo, Deok-Seok

2013-01-01

138

Structures and ice-binding faces of the alanine-rich type I antifreeze proteins.  

Science.gov (United States)

Antifreeze proteins (AFPs) protect cold-blooded organisms from the damage caused by freezing through their ability to inhibit ice growth. The type I AFP family, found in several fish species, contains proteins that have a high alanine content (>60% of the sequence) and structures that are almost all alpha-helical. We examine the structure of the type I AFP isoforms HPLC6 from winter flounder, shorthorn sculpin 3, and the winter flounder hyperactive type I AFP. The HPLC6 isoform structure consists of a single alpha-helix that is 37 residues long, whereas the shorthorn sculpin 3 isoform consists of two helical regions separated by a kink. The high-resolution structure of the hyperactive type I AFP has yet to be determined, but circular dichroism data and analytical ultracentrifugation suggest that the 195 residue protein is a side-by-side dimer of two alpha-helices. The alanine-rich ice-binding faces of HPLC6 and hyperactive type I AFP are discussed, and we propose that the ice-binding face of the shorthorn sculpin 3 AFP contains Ala14, Ala19, and Ala25. We also propose that the denaturation of hyperactive type I AFP at room temperature is explained by the stabilization of the dimerization interface through hydrogen bonds. PMID:20453925

Patel, Shruti N; Graether, Steffen P

2010-04-01

139

Electronic structures of 122- and 111-type silicides and germanides in comparison to iron pnictide superconductors  

Science.gov (United States)

Despite the high transition temperatures, iron pnictide superconductors have difficulty in practical use, due to high toxicity of pnictogens. Besides, the parent crystal structures of iron-based superconductors have been observed over wide range of constituent elements. In this study, we investigated the electronic structures of ThCr2Si2 (122)-type and CeFeSi (111)-type compounds containing Si or Ge instead of pnictogens. While superconducting AFe2As2 (A: group 1-2 elements) has cylindrical Fermi surfaces with strong interband nesting, Fermi surfaces of isoelectronic compounds such as `ACo2Ge2' did not have these characteristics, mainly due to distortion of the `CoGe4' tetrahedra. We investigated the relationship between the crystal geometry and the chemical species of 122- and 111-type compounds, and calculated their effects onto the electronic structures. We found that 111-type phases tend to have smaller distortion of tetrahedra than 122-type phases, although more electron-deficient metals must be chosen in order to reproduce the electronic structures of the superconducting phases. We will suggest some compositions that are expected to reproduce such electronic structures, and report about the synthesis of these compounds.

Katsura, Yukari; Takagi, Hidenori

2010-03-01

140

1H and 15N NMR resonance assignments and secondary structure of titin type I domains  

International Nuclear Information System (INIS)

Titin/connect in is a giant muscle protein with a highly modular architecture consisting of multiple repeats of two sequence motifs, named type I and type II. Type I modules have been suggested to be intracellular members of the fibronectin type III (Fn3) domain family. Along the titin sequence they are exclusively present in the region of the molecule located in the sarcomere A-band. This region has been shown to interact with myosin and C-protein. One of the most noticeable features of type I modules is that they are particularly rich in semiconserved prolines, since these residues account for about 8% of their sequence. We have determined the secondary structure of a representative type I domain (A71) by 15N and 1HNMR. We show that the type I domains of titin have the Fn3 fold as proposed, consisting of a three- and a four-stranded ?-sheet. When the two sheets are placed on top of each other to form the ?-sandwich characteristic of the Fn3 fold, 8 out of 10 prolines are found on the same side of the molecule and form an exposed hydrophobic patch. This suggests that the semiconserved prolines might be relevant for the function of type I modules, providing a surface for binding to other A-band proteins. The secondary structure of A71 was structurally aligned to other extracellular Fn3 modules of known 3D structure. The alignment shows that titin type I modules have closest similarity to the first Fn3 domain of Drosophila neuroglianoglian

141

DFGmodel: predicting protein kinase structures in inactive states for structure-based discovery of type-II inhibitors.  

Science.gov (United States)

Protein kinases exist in equilibrium of active and inactive states, in which the aspartate-phenylalanine-glycine motif in the catalytic domain undergoes conformational changes that are required for function. Drugs targeting protein kinases typically bind the primary ATP-binding site of an active state (type-I inhibitors) or utilize an allosteric pocket adjacent to the ATP-binding site in the inactive state (type-II inhibitors). Limited crystallographic data of protein kinases in the inactive state hampers the application of rational drug discovery methods for developing type-II inhibitors. Here, we present a computational approach to generate structural models of protein kinases in the inactive conformation. We first perform a comprehensive analysis of all protein kinase structures deposited in the Protein Data Bank. We then develop DFGmodel, a method that takes either a known structure of a kinase in the active conformation or a sequence of a kinase without a structure, to generate kinase models in the inactive conformation. Evaluation of DFGmodel's performance using various measures indicates that the inactive kinase models are accurate, exhibiting RMSD of 1.5 Å or lower. The kinase models also accurately distinguish type-II kinase inhibitors from likely nonbinders (AUC > 0.70), suggesting that they are useful for virtual screening. Finally, we demonstrate the applicability of our approach with three case studies. For example, the models are able to capture inhibitors with unintended off-target activity. Our computational approach provides a structural framework for chemical biologists to characterize kinases in the inactive state and to explore new chemical spaces with structure-based drug design. PMID:25420233

Ung, Peter Man-Un; Schlessinger, Avner

2015-01-16

142

Crystal structure of a synthetic tin-selenium representative of the cylindrite structure type.  

Czech Academy of Sciences Publication Activity Database

Ro?. 93, 11-12 (2008), s. 1787-1798. ISSN 0003-004X R&D Projects: GA ?R GA202/06/0757 Institutional research plan: CEZ:AV0Z10100521 Keywords : cylindrite * tin -antimony-iron selenide * non-commensurate layer structure * layer-misfit structure * interlayer match Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.962, year: 2008

Makovicky, E.; Pet?í?ek, Václav; Dušek, Michal; Topa, D.

2008-01-01

143

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

OpenAIRE

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...

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

2009-01-01

144

Kinetics of formation of twinned structures under L1_0 type orderings in alloys  

OpenAIRE

The earlier-developed master equation approach and kinetic cluster methods are applied to study kinetics of L1_0 type orderings in alloys, including the formation of twinned structures characteristic of cubic-tetragonal-type phase transitions. A microscopical model of interatomic deformational interactions is suggested which generalizes a similar model of Khachaturyan for dilute alloys to the physically interesting case of concentrated alloys. The model is used to simulate A...

Belashchenko, K. D.; Pankratov, I. R.; Samolyuk, G. D.; Vaks, V. G.

2001-01-01

145

Unique Structural Elements Dictate the Specificity of the Type III Pentaketide Synthase from Neurospora crassa  

OpenAIRE

Enzymes in the chalcone synthase superfamily of type III polyketide synthases (PKSs) produce a wide variety of polyketide compounds, distinct in terms of both structure and biological function. The first fungal type III PKS to be characterized, Neurospora crassa 2?-oxoalkylresorcylic acid synthase (ORAS), was demonstrated to prime with a range of acyl-Coenzyme A thioesters (C4—C20) and extend using malonyl-Coenzyme A, thereby producing pyrone, resorcinol, and resorcylic acid products. To ...

Rubin-pitel, Sheryl B.; Zhang, Houjin; Vu, Trang; Brunzelle, Joseph S.; Zhao, Huimin; Nair, Satish K.

2008-01-01

146

Classification of urban structural types (UST) using multiple data sources and spatial priors  

OpenAIRE

Remote sensing and geographic information science offer many pos- sibilities in terms of availability of diverse data. Some products like land cover layers or digital elevation models can be extracted from imagery and enable the realization of 3D city models. Starting from these morphological and geographical sources, an approach is proposed to extract information about urban structure types (UST), i.e. types of urban habitat at the neighborhoodscale. We propose an effective processing chain ...

Poncet Montanges, Arnaud

2014-01-01

147

The reproducing kernel structure associated with certain Fourier type systems and their quantum analogues  

CERN Document Server

We study mapping properties of operators with kernels defined via an abstract formulation of quantum ($q$-) Fourier type systems. We prove M. E. H. Ismail conjecture regarding the existence of a reproducing kernel structure behind these kernels. The results are illustrated with Fourier kernels with ultraspherical and Jacobi weights, their continuous $q$-extensions and generalizations. As a byproduct of this approach, a new class of sampling theorems is obtained, as well as Neumann type expansions in Bessel and $q$% -Bessel functions.

Abreu, L D

2006-01-01

148

Structure-Based Design of Type II Inhibitors Applied to Maternal Embryonic Leucine Zipper Kinase.  

Science.gov (United States)

A novel Type II kinase inhibitor chemotype has been identified for maternal embryonic leucine zipper kinase (MELK) using structure-based ligand design. The strategy involved structural characterization of an induced DFG-out pocket by protein-ligand X-ray crystallography and incorporation of a slender linkage capable of bypassing a large gate-keeper residue, thus enabling design of molecules accessing both hinge and induced pocket regions. Optimization of an initial hit led to the identification of a low-nanomolar, cell-penetrant Type II inhibitor suitable for use as a chemical probe for MELK. PMID:25589926

Johnson, Christopher N; Adelinet, Christophe; Berdini, Valerio; Beke, Lijs; Bonnet, Pascal; Brehmer, Dirk; Calo, Frederick; Coyle, Joseph E; Day, Phillip J; Frederickson, Martyn; Freyne, Eddy J E; Gilissen, Ron A H J; Hamlett, Christopher C F; Howard, Steven; Meerpoel, Lieven; Mevellec, Laurence; McMenamin, Rachel; Pasquier, Elisabeth; Patel, Sahil; Rees, David C; Linders, Joannes T M

2015-01-01

149

Equivalent linearization method for limit cycle flutter analysis of plate-type structure in axial flow  

International Nuclear Information System (INIS)

The responses and limit cycle flutter of a plate-type structure with cubic stiffness in viscous flow were studied. The continuous system was dispersed by utilizing Galerkin Method. The equivalent linearization concept was performed to predict the ranges of limit cycle flutter velocities. The coupled map of flutter amplitude-equivalent linear stiffness-critical velocity was used to analyze the stability of limit cycle flutter. The theoretical results agree well with the results of numerical integration, which indicates that the equivalent linearization concept is available to the analysis of limit cycle flutter of plate-type structure. (authors)

150

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

Science.gov (United States)

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.

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

2015-03-01

151

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

International Nuclear Information System (INIS)

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)

152

High-pressure U3O8 with the fluorite-type structure  

International Nuclear Information System (INIS)

A new high-pressure phase of U3O8, which has a fluorite-type structure, forms at pressures greater than ?8.1 GPa that was confirmed by in situ x-ray diffraction (XRD) measurements. The fluorite-type U3O8 is stable at pressures at least up to ?40 GPa and temperatures to 1700 K, and quenchable to ambient conditions. Based on the XRD analysis, there is a huge volume collapse (>20%) for U3O8 during the phase transition and the quenched high-pressure phase is 28% denser than the initial orthorhombic phase at ambient conditions. The high-pressure phase has a very low compressibility comparing with the starting orthorhombic phase. - Graphical abstract: ?-U3O8 is in a layered structure with orthorhombic symmetry, at high pressures, it transformed to a fluorite-type cubic structure. There are a lot of defects in the cubic structure, and it is a new kind of hyperstoichiometric uranium oxide, which is stable at ambient conditions. - Highlights: • A new fluorite-type high-pressure phase was found in hyperstoichometric UO2+x (x?0.8). • The new high-pressure structure is quenchable to ambient conditions. • Pressure driven phase transition in orthorhombic U3O8 was first found

153

Structural variations in ?-type Al-Pd-(Mn, Fe) complex metallic alloy phases  

OpenAIRE

Abstract Structural modifications in complex metallic ?-Al-Pd-(Mn, Fe) samples are studied by means of transmission electron microscopy. The modifications were observed in the vicinity of metadislocations and at phase boundaries. They are determined by the density and inclination of phason planes. In the vicinity of metadislocations and at an ?6-?28-phase boundary, new monoclinic ?-type structures appear locally, which were not detected as bulk phases in...

Heggen, Marc; Engel, Michael; Balanetskyy, Sergiy; Trebin, Hans-rainer; Feuerbacher, M.

2008-01-01

154

Parallel conduction in p-type gallium nitride homo-structures  

International Nuclear Information System (INIS)

Usually the multi-layer technique is applied for the growth of p-type gallium nitride (GaN) films, and the active p-type layer is deposited on an n-type GaN buffer layer. In the present paper, the electrical transport phenomena (conductivity and Hall effect) have been studied in p-GaN/GaN homo-structures grown on a sapphire substrate. Two types of GaN buffer layers were used: a silicon-doped one and another strongly compensated by magnesium. We demonstrate that in the analysis of the electrical conduction phenomena the parallel conduction in the n-type buffer layer cannot be neglected, and it manifests itself in the studies of a conduction process as a function of temperature and as a function of electric field intensity

155

Covariance Structures under Polynomical Constraints: Applications to Correlation and Alpha-Type Structural Models.  

Science.gov (United States)

A method for the estimation of covariance structure models under polynomial constraints (such as quadratic constraints) is presented. Estimation is on maximum likelihood principles, and the test statistics, parameter estimates, and standard errors are based on a statistical theory which takes the constraints into account. (Author/JKS)

Bentler, P. M.; Lee, Sik-Yum

1983-01-01

156

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

International Nuclear Information System (INIS)

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, thller 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.

157

Structure evolution of Cu-Cu type clusters in Cu-In alloy melts  

International Nuclear Information System (INIS)

The structure of Cu-12at.%In and Cu-23at.%In alloy melts were studied by using a high-temperature X-ray diffractometer. The radial distribution functions (RDF) were obtained, which reflect the structure information of melts in real space. Gaussian decomposition of the RDFs shows the changing behavior of Cu-Cu type clusters in the melts. The interatomic distance and the atom number of the clusters decrease with increasing temperature. The structure evolution and the so-called 'thermal contraction' of clusters in the melts are discussed

158

Crystal structures and magnetic properties of iron (III)-based phosphates: Na{sub 4}NiFe(PO{sub 4}){sub 3} and Na{sub 2}Ni{sub 2}Fe(PO{sub 4}){sub 3}  

Energy Technology Data Exchange (ETDEWEB)

Graphical abstract: A perspective view of the Na{sub 2}Ni{sub 2}Fe(PO{sub 4}){sub 3} structure along the [0 0 1] direction. Both compounds seem to exibit antiferromagnetic interactions between magnetic entities at low temperature. Display Omitted Research highlights: > Nasicon and Alluaudite compounds, Iron(III)-based phosphates, Crystal structures of Na{sub 4}NiFe(PO{sub 4}){sub 3} and Na{sub 2}Ni{sub 2}Fe(PO{sub 4}){sub 3}. > Magnetism behaviours of Na{sub 4}NiFe(PO{sub 4}){sub 3} and Na{sub 2}Ni{sub 2}Fe(PO{sub 4}){sub 3}. > Antiferromagnetism interactions. > Mossbauer spectroscopy. - Abstract: Crystal structures from two new phosphates Na{sub 4}NiFe(PO{sub 4}){sub 3} (I) and Na{sub 2}Ni{sub 2}Fe(PO{sub 4}){sub 3} (II) have been determined by single crystal X-ray diffraction analysis. Compound (I) crystallizes in a rhombohedral system (S. G: R-3c, Z = 6, a = 8.7350(9) A, c = 21.643(4) A, R{sub 1} = 0.041, wR{sub 2}=0.120). Compound (II) crystallizes in a monoclinic system (S. G: C2/c, Z = 4, a = 11.729(7) A, b = 12.433(5) A, c = 6.431(2) A, {beta} = 113.66(4){sup o}, R{sub 1} = 0.043, wR{sub 2}=0.111). The three-dimensional structure of (I) is closely related to the Nasicon structural type, consisting of corner sharing [(Ni/Fe)O{sub 6}] octahedra and [PO{sub 4}] tetrahedra forming [NiFe(PO{sub 4}){sub 3}]{sup 4+} units which align in chains along the c-axis. The Na{sup +} cations fill up trigonal antiprismatic sites within these chains. The crystal structure of (II) belongs to the alluaudite type. Its open framework results from [Ni{sub 2}O{sub 10}] units of edge-sharing [NiO{sub 6}] octahedra, which alternate with [FeO{sub 6}] octahedra that form infinite chains. Coordination of these chains yields two distinct tunnels in which site Na{sup +}. The magnetization data of compound (I) reveal antiferromagnetic (AFM) interactions by the onset of deviations from a Curie-Weiss behaviour at low temperature as confirmed by Moessbauer measurements performed at 4.2 K. The corresponding temperature dependence of the reciprocal susceptibility {chi}{sup -1} follows a typical Curie-Weiss behaviour for T > 105 K. A canted AFM state is proposed for compound (II) below 46 K with a field-induced magnetic transition at H {approx} 19 kOe, revealed in the hysteresis loop measured at 5 K. This transition is most probably associated with a spin-flop transition.

Essehli, Rachid, E-mail: rachid_essehli@yahoo.fr [Laboratory of Mineral Solid and Analytical Chemistry ' LCSMA' , 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 ' LCSMA' , Department of Chemistry, Faculty of Sciences, University Mohamed I, Po. Box 717, 60000 Oujda (Morocco); Benmokhtar, Said [LCMS, Laboratoire de Chimie des Materiaux Solides, Departement de chimie, Faculte des Sciences Ben M' SIK, Casablanca (Morocco); Bouziane, Khalid [Physics Department, College of Science, Sultan Qaboos University, PO Box 36, Postal Code 123 Al Khod, Sultanate of Oman (Oman); Manoun, Bouchaib [Laboratoire de Physico-Chimie des Materiaux, Departement de Chimie, FST Errachidia, University Moulay Ismail, B.P. 509 Boutalamine, Errachidia (Morocco); Abdalslam, Mouner Ahmed [Materials Science, Technical University Darmstadt, Darmstadt (Germany); Ehrenberg, Helmut [IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany)

2011-01-28

159

Compounds of AuBe5 type structure in (Zr,Hf)-Cu-In systems  

International Nuclear Information System (INIS)

The crystal structure of the ZrCu5-xInx compound (x = 0.3-1.3), a 0.6955-0.7042 (2) nm (str.type AuBe5, sp.group F43m) is decoded through the powder method (autodiffractometry HZG-4a, CuK?-irradiation)

160

Observation of a high burnup rim-type structure in an advanced plutonium uranium carbide fuel  

Science.gov (United States)

The observation is reported of a `rim-type' structure with small subgrains in an advanced plutonium-uranium carbide (U 0.8Pu 0.2)C fuel pin, which had been irradiated in the Dounreay Fast Reactor to a burnup of 8.3% FIMA.

Ray, I. L. F.; Matzke, Hj

1997-12-01

161

Structure cristalline de type alluaudite KNa5Mn3(MoO4)6.  

Science.gov (United States)

The new phase potassium penta-sodium trimanganese hexa-kis(molybdate), KNa5Mn3Mo6O24, has been synthesized using solid-state methods. The structure is composed of M 2O10 (M = Mn, Na) dimers and MoO4 tetra-hedra (point group symmetry 2) sharing corners and forming layers parallel to (100), which are linked via common corners of another type of MO4 tetra-hedra, forming a three-dimensional structure with two types of large channels along [001] in which two types of Na(+) cations (one with site symmetry 2, one with -1) and K(+) cations (site symmetry 2, half-occupation) are located. Mn(2+) and the third type of Na(+) cations are located at the same site M with occupancies of 0.75 and 0.25, respectively. A comparative structural description is provided between the structure of the title compound and those of the related phases Cu1.35Fe3(PO4)3 and NaAgFeMn2(PO4)3. PMID:25705454

Bouzidi, Chahira; Frigui, Wafa; Zid, Mohamed Faouzi

2015-01-01

162

Study of interfaces chemistry in type-II GaSb/InAs superlattice structures  

International Nuclear Information System (INIS)

There is a considerable interest in type-II GaSb/InAs superlattice system due to several modern applications including infrared detectors. In these studies X-ray photoelectron spectroscopy (XPS) and spectroscopic ellipsometry (SE) have been used for extensive characterization of the surface and interface of GaSb/InAs superlattice. Application of XPS and SE techniques provides precise information from topmost layers of structure and allows excluding presence of GaAs-type interfaces in GaSb/InAs superlattices. It means that Sb-for-As anion exchange does not exist during the molecular beam epitaxial growth of superlattice structures. Simultaneously, these results indicate that InSb-type or GaInSb-type interfaces have been detected in the structures studied. - Highlights: ? The complementary study of InAs/GaSb superlattice interfaces has been proposed. ? InSb and GaInSb interfaces in InAs/GaSb superlattices have been shown. ? The presence of GaAs-type interface in InAs/GaSb superlattices was excluded. ? Sb-for-As exchange during InAs/GaSb superlattice epitaxial growth does not exist.

163

Structure and Evolutionary Origin of Ca2+-Dependent Herring Type II Antifreeze Protein  

Energy Technology Data Exchange (ETDEWEB)

In order to survive under extremely cold environments, many organisms produce antifreeze proteins (AFPs). AFPs inhibit the growth of ice crystals and protect organisms from freezing damage. Fish AFPs can be classified into five distinct types based on their structures. Here we report the structure of herring AFP (hAFP), a Ca2+-dependent fish type II AFP. It exhibits a fold similar to the C-type (Ca2+-dependent) lectins with unique ice-binding features. The 1.7 Angstroms crystal structure of hAFP with bound Ca2+ and site-directed mutagenesis reveal an ice-binding site consisting of Thr96, Thr98 and Ca2+-coordinating residues Asp94 and Glu99, which initiate hAFP adsorption onto the [10-10] prism plane of the ice lattice. The hAFP-ice interaction is further strengthened by the bound Ca2+ through the coordination with a water molecule of the ice lattice. This Ca2+-coordinated ice-binding mechanism is distinct from previously proposed mechanisms for other AFPs. However, phylogenetic analysis suggests that all type II AFPs evolved from the common ancestor and developed different ice-binding modes. We clarify the evolutionary relationship of type II AFPs to sugar-binding lectins.

Liu,Y.; Li, Z.; Lin, Q.; Kosinski, J.; Seetharaman, J.; Bujnicki, J.; Sivaraman, J.; Hew, C.

2007-01-01

164

Tectonic types of deepwater basins and structural segmentation of the North Atlantic  

Science.gov (United States)

Typification of tectonic structures is one of the important lines of tectonic research. Recently, I have published several articles, which are concerned with deepwater oceanic basins. This paper is focused on tectonic typification of deepwater basins of the North Atlantic. They are attributed to three types: perispreading, central thalassogenic, and pericontinental. The first type comprises the Irminger, Iceland, Greenland, and Lofoten basins. The first two basins are associated with the Reykjanes Ridge and the two others, with the Mohns Ridge. The central thalassogenic type is exemplified in the Norwegian Basin, while the pericontinental type in the Rockall Trough. Two systems of basins are distinguished by morphostructural and historical-geological features: the northern system of the Oligocene-Quaternary structures and the southern system of the Paleocene-Quaternary structures. The Greenland-Faroe tectonovolcanic zone serves as their tectonic interface. In the tectonic typology of their deepwater basins, the North Atlantic is closer to the Indian than to other oceans. The present-day configuration of the northern basins is determined by neotectonics. The tectonic movements in the northern system of basins at this stage were more contrasting than in the southern system. This explains the greater depth of the former basins. The spatial position of the deepwater basins belonging to different types determines the tectonic segmentation of the oceanic bottom. The southern, central, and northern latitudinal segments correspond to different geodynamic states of the Earth's interior.

Pushcharovsky, Yu. M.

2012-03-01

165

Study of interfaces chemistry in type-II GaSb/InAs superlattice structures  

Energy Technology Data Exchange (ETDEWEB)

There is a considerable interest in type-II GaSb/InAs superlattice system due to several modern applications including infrared detectors. In these studies X-ray photoelectron spectroscopy (XPS) and spectroscopic ellipsometry (SE) have been used for extensive characterization of the surface and interface of GaSb/InAs superlattice. Application of XPS and SE techniques provides precise information from topmost layers of structure and allows excluding presence of GaAs-type interfaces in GaSb/InAs superlattices. It means that Sb-for-As anion exchange does not exist during the molecular beam epitaxial growth of superlattice structures. Simultaneously, these results indicate that InSb-type or GaInSb-type interfaces have been detected in the structures studied. - Highlights: Black-Right-Pointing-Pointer The complementary study of InAs/GaSb superlattice interfaces has been proposed. Black-Right-Pointing-Pointer InSb and GaInSb interfaces in InAs/GaSb superlattices have been shown. Black-Right-Pointing-Pointer The presence of GaAs-type interface in InAs/GaSb superlattices was excluded. Black-Right-Pointing-Pointer Sb-for-As exchange during InAs/GaSb superlattice epitaxial growth does not exist.

Papis-Polakowska, E., E-mail: papis@ite.waw.pl [Institute of Electron Technology, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Kaniewski, J. [Institute of Electron Technology, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Szade, J. [A. Chelkowski Institute of Physics, University of Silesia ul. Uniwersytecka 4, 40-007 Katowice (Poland); Rzodkiewicz, W.; Jasik, A.; Reginski, K. [Institute of Electron Technology, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Wawro, A. [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw (Poland)

2012-11-01

166

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

International Nuclear Information System (INIS)

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 ?2- and ?5-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

167

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

International Nuclear Information System (INIS)

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)

168

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

International Nuclear Information System (INIS)

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

169

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

International Nuclear Information System (INIS)

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)

170

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

Science.gov (United States)

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

Zeier, Wolfgang G

2014-11-21

171

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

International Nuclear Information System (INIS)

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

172

Structural aspects of a higher order nucleoprotein complex: induction of an altered DNA structure at the Mu-host junction of the Mu type 1 transpososome.  

OpenAIRE

The Mu in vitro strand transfer reaction proceeds via two stable higher order nucleoprotein complexes, the Type 1 and Type 2 transpososomes. The Mu A protein is responsible for the structural and functional integrity of the Type 1 transpososome. We have investigated the quaternary structure of the Mu A protein within this complex by chemical cross-linking experiments and found that the basic structural unit is an A tetramer. Three Mu A binding sites in the transpososome are protected by DNase...

Lavoie, B. D.; Chan, B. S.; Allison, R. G.; Chaconas, G.

1991-01-01

173

Structure of Salmonella FlhE, Conserved Member of a Flagellar Type III Secretion Operon.  

Science.gov (United States)

The bacterial flagellum is assembled by a multicomponent transport apparatus categorized as a type III secretion system. The secretion of proteins that assemble into the flagellum is driven by the proton motive force. The periplasmic protein FlhE is a member of the flhBAE operon in the majority of bacteria where FlhE is found. FlhA and FlhB are established components of the flagellar type III secretion system. The absence of FlhE results in a proton leak through the flagellar system, inappropriate secretion patterns, and cell death, indicating that FlhE regulates an important aspect of proper flagellar biosynthesis. We isolated FlhE from the periplasm of Salmonella and solved its structure to 1.5Å resolution. The structure reveals a ?-sandwich fold, with no close structural homologs. Possible roles of FlhE, including that of a chaperone, are discussed. PMID:25545591

Lee, Jaemin; Monzingo, Arthur F; Keatinge-Clay, Adrian T; Harshey, Rasika M

2015-03-27

174

Solution structure of homology region (HR) domain of type II secretion system.  

Science.gov (United States)

The type II secretion system of Gram-negative bacteria is important for bacterial pathogenesis and survival; it is composed of 12 mostly multimeric core proteins, which build a sophisticated secretion machine spanning both bacterial membranes. OutC is the core component of the inner membrane subcomplex thought to be involved in both recognition of substrate and interaction with the outer membrane secretin OutD. Here, we report the solution structure of the HR domain of OutC and explore its interaction with the secretin. The HR domain adopts a ?-sandwich-like fold consisting of two ?-sheets each composed of three anti-parallel ?-strands. This structure is strikingly similar to the periplasmic region of PilP, an inner membrane lipoprotein from the type IV pilus system highlighting the common evolutionary origin of these two systems and showing that all the core components of the type II secretion system have a structural or sequence ortholog within the type IV pili system. The HR domain is shown to interact with the N0 domain of the secretin. The importance of this interaction is explored in the context of the functional secretion system. PMID:22253442

Gu, Shuang; Kelly, Geoff; Wang, Xiaohui; Frenkiel, Tom; Shevchik, Vladimir E; Pickersgill, Richard W

2012-03-16

175

Solution Structure of Homology Region (HR) Domain of Type II Secretion System*  

Science.gov (United States)

The type II secretion system of Gram-negative bacteria is important for bacterial pathogenesis and survival; it is composed of 12 mostly multimeric core proteins, which build a sophisticated secretion machine spanning both bacterial membranes. OutC is the core component of the inner membrane subcomplex thought to be involved in both recognition of substrate and interaction with the outer membrane secretin OutD. Here, we report the solution structure of the HR domain of OutC and explore its interaction with the secretin. The HR domain adopts a ?-sandwich-like fold consisting of two ?-sheets each composed of three anti-parallel ?-strands. This structure is strikingly similar to the periplasmic region of PilP, an inner membrane lipoprotein from the type IV pilus system highlighting the common evolutionary origin of these two systems and showing that all the core components of the type II secretion system have a structural or sequence ortholog within the type IV pili system. The HR domain is shown to interact with the N0 domain of the secretin. The importance of this interaction is explored in the context of the functional secretion system. PMID:22253442

Gu, Shuang; Kelly, Geoff; Wang, Xiaohui; Frenkiel, Tom; Shevchik, Vladimir E.; Pickersgill, Richard W.

2012-01-01

176

The structure of the R8 term in type IIB string theory  

International Nuclear Information System (INIS)

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)

177

Integrability of and differential–algebraic structures for spatially 1D hydrodynamical systems of Riemann type  

International Nuclear Information System (INIS)

Highlights: • A new differential–algebraic–geometric approach for testing integrability is described. • The approach is applied to a generalized Riemann type hydrodynamic system. • The approach is applied to a generalized Ostrovsky–Vakhnenko system. • The approach is applied to a new two-component Burgers type hydrodynamic system. -- Abstract: A differential–algebraic approach to studying the Lax integrability of a generalized Riemann type hydrodynamic hierarchy is revisited and a new Lax representation is constructed. The related bi-Hamiltonian integrability and compatible Poissonian structures of this hierarchy are also investigated using gradient-holonomic and geometric methods. The complete integrability of a new generalized Riemann hydrodynamic system is studied via a novel combination of symplectic and differential–algebraic tools. A compatible pair of polynomial Poissonian structures, a Lax representation and a related infinite hierarchy of conservation laws are obtained. In addition, the differential–algebraic approach is used to prove the complete Lax integrability of the generalized Ostrovsky–Vakhnenko and a new Burgers type system, and special cases are studied using symplectic and gradient-holonomic tools. Compatible pairs of polynomial Poissonian structures, matrix Lax representations and infinite hierarchies of conservation laws are derived

178

High-pressure structural investigation of several zircon-type orthovanadates  

CERN Document Server

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.

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

2010-01-01

179

Isolation and X-ray crystal structure of a securinega-type alkaloid from Phyllanthus niruri Linn.  

Science.gov (United States)

A securinega-type alkaloid epibubbialine was isolated from Phyllanthus niruri Linn. Its structure was established by spectroscopic methods and X-ray single-crystal diffraction analysis. Its crystal structure is reported herein for the first time. PMID:21878003

Zhou, Min; Zhu, Honglin; Wang, Kuiwu; Wei, Wanxing; Zhang, Yong

2012-01-01

180

In-vineyard population structure of 'Candidatus Phytoplasma solani' using multilocus sequence typing analysis.  

Science.gov (United States)

'Candidatus Phytoplasma solani' is a phytoplasma of the stolbur group (16SrXII subgroup A) that is associated with 'Bois noir' and causes heavy damage to the quality and quantity of grapevine yields in several European countries, and particularly in the Mediterranean area. Analysis of 'Ca. P. solani' genetic diversity was carried out for strains infecting a cv. 'Chardonnay' vineyard, through multilocus sequence typing analysis for the vmp1, stamp and secY genes. Several types per gene were detected: seven out of 20 types for vmp1, six out of 17 for stamp, and four out of 16 for secY. High correlations were seen among the vmp1, stamp and secY typing with the tuf typing. However, no correlations were seen among the tuf and vmp1 types and the Bois noir severity in the surveyed grapevines. Grouping the 'Ca. P. solani' sequences on the basis of their origins (i.e., study vineyard, Italian regions, Euro-Mediterranean countries), dN/dS ratio analysis revealed overall positive selection for stamp (3.99, P=0.019) and vmp1 (2.28, P=0.001). For secY, the dN/dS ratio was 1.02 (P=0.841), showing neutral selection across this gene. Using analysis of the nucleotide sequencing by a Bayesian approach, we determined the population structure of 'Ca. P. solani', which appears to be structured in 3, 5 and 6 subpopulations, according to the secY, stamp and vmp1 genes, respectively. The high genetic diversity of 'Ca. P. solani' from a single vineyard reflects the population structure across wider geographical scales. This information is useful to trace inoculum source and movement of pathogen strains at the local level and over long distances. PMID:25660034

Murolo, Sergio; Romanazzi, Gianfranco

2015-04-01

181

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

International Nuclear Information System (INIS)

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 sucher 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.

182

Precision photonic band structure calculation of Abrikosov periodic lattice in type-II superconductors  

CERN Document Server

We have performed a numerical solution for band structure of an Abrikosov vortex lattice in type-II superconductors forming a periodic array in two dimensions for applications of incorporating the photonic crystals concept into superconducting materials with possibilities for optical electronics. The implemented numerical method is based on the extensive numerical solution of the Ginzburg-Landau equation for calculating the parameters of the two-fluid model and obtaining the band structure from the permittivity, which depends on the above parameters and the frequency. This is while the characteristics of such crystals highly vary with an externally applied static normal magnetic field, leading to nonlinear behavior of the band structure, which also has nonlinear dependence on the temperature. The similar analysis for every arbitrary lattice structure is also possible to be developed by this approach as presented in this work. We also present some examples and discuss the results.

Kokabi, Alireza; Khorasani, Sina; Fardmanesh, Mehdi

2011-01-01

183

Habitat Evaluation on Scour Hole Downflow Low Drop Structure Types Using Large-Scale Experiment  

Directory of Open Access Journals (Sweden)

Full Text Available This study sought to review whether large-scale experimentation can apply to actual rivers concerning the effect of topographical change by scour in the downstream area of natural-type low drop structures on the fish habitat. The large-scale applicability experiment performed in this study installed low drop structures as the study object within the experiment channel and precisely surveyed topography in the downstream area of drop structures along with the hydraulic amount including water level and flow velocity under certain flow conditions. Based on topographical data acquired through the survey after the experiment ended, this study reviewed the change of suitability index and difference of weighted usable area by performing 2D habitat simulation. Ultimately, through the habitat simulation results in cases of considering and not considering scour in the downstream area of drop structures, this study analyzed the effects of topographical change in actual rivers on the habitat.

Joongu Kang

2012-09-01

184

Phosphorylation of Structural Components Promotes Dissociation of the Herpes Simplex Virus Type 1 Tegument  

OpenAIRE

The role of phosphorylation in the dissociation of structural components of the herpes simplex virus type 1 (HSV-1) tegument was investigated, using an in vitro assay. Addition of physiological concentrations of ATP and magnesium to wild-type virions in the presence of detergent promoted the release of VP13/14 and VP22. VP1/2 and the UL13 protein kinase were not significantly solubilized. However, using a virus with an inactivated UL13 protein, we found that the release of VP22 was severely i...

Morrison, Ewan E.; Wang, Yi-fen; Meredith, David M.

1998-01-01

185

Spectral Structures and Their Generation Mechanisms for Solar Radio Type-I Bursts  

OpenAIRE

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 AMATEAS 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 th...

Iwai, Kazumasa; Miyoshi, Yoshizumi; Masuda, Satoshi; Tsuchiya, Fuminori; Morioka, Akira; Misawa, Hiroaki

2014-01-01

186

Crystal structure of the Yersinia type III secretion protein YscE  

Energy Technology Data Exchange (ETDEWEB)

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.

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

2010-12-06

187

Structural comparison of n-type and p-type LaAlO3/SrTiO3 interfaces.  

Science.gov (United States)

Using a surface x-ray diffraction technique, we investigated the atomic structure of two types of interfaces between LaAlO3 and SrTiO3, that is, p-type (SrO/AlO2) and n-type (TiO2/LaO) interfaces. Our results demonstrate that the SrTiO3 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, atomic intermixing was observed to extend deeper into the SrTiO3 substrate at the n-type interface compared to the p type. These differences result in distinct degrees of band bending, which likely contributes to the striking contrast in electrical conductivity between the two types of interfaces. PMID:21838380

Yamamoto, Ryosuke; Bell, Christopher; Hikita, Yasuyuki; Hwang, Harold Y; Nakamura, Hiroyuki; Kimura, Tsuyoshi; Wakabayashi, Yusuke

2011-07-15

188

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

Energy Technology Data Exchange (ETDEWEB)

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.

Bell, Christopher

2011-08-19

189

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

Directory of Open Access Journals (Sweden)

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.

Mehmet TERZ?

2006-03-01

190

La structure cristalline de Cr 2P: Distorsion orthorhombique de la structure hexagonale de type Fe 2P  

Science.gov (United States)

La structure cristalline du composé Cr 2P a été affinée par la méthode de Rietveld, à partir d'un diagramme de diffraction neutronique sur poudre. Elle est orthorhombique, de groupe spatial Imm2, et paramètres de maille a= 6,6097(1) Å, b= 10,4023(2) Å, c= 6,3371(1) Å. Elle dérive du type hexagonal Fe 2P par un mécanisme de déformation, mettant en jeu des déplacements importants de certains atomes de chrome suivant l'axe chexagonal qui donnent lieu à un renforcement de quelques liaisons chrome-chrome dans cette direction. La déformation est le résultat d'une compétition entre les interactions d-det les interactions d-p, le renforcement relatif des premières s'effectue au détriment des secondes. The crystal structure of Cr 2P has been determined using the profile refinement method from neutron diffraction data. It is orthorhombic, space group Imm2, and lattice parameters a= 6.6097(1) Å, b= 10.4023(2) Å, c= 6.3371(1) Å. The crystal structure derives from the hexagonal Fe 2P-type by a distortion mechanism which implies atomic shifts of the Cr atoms parallel to the hexagonal caxis leading to the formation of Cr-Cr bonds in this direction. The distortion results from an interplay between the competing d- dand d- phybridizations.

Artigas, M.; Bacmann, M.; Fruchart, D.; Fruchart, R.

1996-05-01

191

Structural basis for recognition of urokinase-type plasminogen activator by plasminogen activator inhibitor-1  

DEFF Research Database (Denmark)

Plasminogen activator inhibitor-1 (PAI-1), together with its physiological target urokinase-type plasminogen activator (uPA), plays a pivotal role in fibrinolysis, cell migration, and tissue remodeling and is currently recognized as being among the most extensively validated biological prognostic factors in several cancer types. PAI-1 specifically and rapidly inhibits uPA and tissue-type PA (tPA). Despite extensive structural/functional studies on these two reactions, the underlying structural mechanism has remained unknown due to the technical difficulties of obtaining the relevant structures. Here, we report a strategy to generate a PAI-1·uPA(S195A) Michaelis complex and present its crystal structure at 2.3-Å resolution. In this structure, the PAI-1 reactive center loop serves as a bait to attract uPA onto the top of the PAI-1 molecule. The P4-P3' residues of the reactive center loop interact extensively with the uPA catalytic site, accounting for about two-thirds of the total contact area. Besides the active site, almost all uPA exosite loops, including the 37-, 60-, 97-, 147-, and 217-loops, are involved in the interaction with PAI-1. The uPA 37-loop makes an extensive interaction with PAI-1 ?-sheet B, and the 147-loop directly contacts PAI-1 ?-sheet C. Both loops are important for initial Michaelis complex formation. This study lays down a foundation for understanding the specificity of PAI-1 for uPA and tPA and provides a structural basis for further functional studies.

Lin, Zhonghui; Jiang, Longguang

2011-01-01

192

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

OpenAIRE

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...

Arumugam, Karthik

2009-01-01

193

UIr, a PdBi-like distorted CrB-type structure  

International Nuclear Information System (INIS)

The room temperature structure of UIr was found to be monoclinic with cell parameters a=7.271(1) A, b=10.578(2) A, c=8.511(1) A, ?=90.16(1)0; Z=16, space group B21. The final residual value for 960 observed reflections was R=0.082 and 0.124 for all 1502 unique reflections. The structure of UIr is a distortion variant of the CrB type similar to that of PdBi, although there the monoclinic angle is acute. The distortions lead to bonds between adjacent iridium zigzag chains. (orig.)

194

Fano-type spectral asymmetry and its control for plasmonic metal-insulator-metal stub structures.  

Science.gov (United States)

We use coupled mode theory (CMT) to analyze a metal-insulator-metal (MIM) plasmonic stub structure, to reveal the existence of asymmetry in its transmittance spectra. Including the effect of the near field contribution for the stub structure, the observed asymmetry is interpreted as Fano-type interference between the quasi-continuum T-junction-resonator local-modes and discrete stub eigenmodes. Based on the asymmetry factor derived from the CMT analysis, methods to control transmittance asymmetry are also demonstrated. PMID:21643350

Piao, Xianji; Yu, Sunkyu; Koo, Sukmo; Lee, Kwanghee; Park, Namkyoo

2011-05-23

195

Half metallic state of (Fe,Co)Si with B20-type structure  

International Nuclear Information System (INIS)

Electronic structures of (Fe1-xCox)Si with a B20-type structure are calculated by the linear muffin-tin orbital method with the atomic sphere approximation. It has been shown that the excess 3d electrons on replaced Co atom for x<0.5 occupy only the majority spin band and the Fermi level lies still in the band gap of the minority spin band. This is consistent with the observed concentration dependence of the spontaneous magnetization at small x. This fact means that the present system may be a ferromagnetic half metal

196

System identification of a truss type space structure using the multiple boundary condition test (MBCT) method  

Science.gov (United States)

Experimental results on the application of the multiple boundary condition test (MBCT) method to experimental hardware have validated its usefulness in the ground testing of large flexible space structures. Excellant results were obtained with a beam with a uniform cross-section and with a beam consisting of two different cross-sections alternately located. The MBCT method is then applied to a 12 bay MAST type structure which is part of the NASA COFS program, and the cross-sectional area of the updated mathematical model was found to be within 4.5 percent of the true value.

Kuo, C. P.; Wada, B. K.

1987-01-01

197

Structural and Electrical Properties of P--Type ZnO Thin Films  

International Nuclear Information System (INIS)

The codoped ZnO thin film were deposited by DC magnetron sputtering on silicon (111) followed by annealing treatment at 200 deg. C to 600 deg. C for 1 hour in nitrogen and oxygen gas mixture. P-type conduction of Al-N codoped ZnO thin films were obtained at 300 deg. C with the lowest resistivity of 3.412x10-3 ?·cm and highest carrier concentration of 1.54x1022 cm-3. Structural investigation was carried out by atomic force microscope (AFM) and X-ray diffraction (XRD). Results showed that heat treatment had influenced the structure of the films

198

Crystallographic Structure of Porcine Adenovirus Type 4 Fiber Head and Galectin Domains?  

OpenAIRE

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 d...

Kahn, Richard; Curiel, David T.; Glasgow, Joel N.; Raaij, Mark J.

2010-01-01

199

New Type Phase Transition of Li2RuO3 with Honeycomb Structure  

OpenAIRE

A new-type structural transition has been found in Li2RuO3 with honeycomb lattice of edge-sharing RuO6-octahedra. With decreasing temperature T, the electrical resistivity exhibits an anomalous increase at T=Tc~540 K, suggesting the (metal to insulator)-like transition and the magnetic susceptibility also shows a sharp decrease. Detailed structure analyses have revealed that the high temperature space group C2/m changes to P21/m at Tc. The most striking fact is that a signif...

Miura, Yoko; Yasui, Yukio; Sato, Masatoshi; Igawa, Naoki; Kakurai, Kazuhisa

2006-01-01

200

Superconductivity in KSn2 with the MgZn2-type structure  

Science.gov (United States)

We report here the sysnthesis and discovery of a new superconductor potassium distannide KSn2. KSn2 has a hexagonal crystal structure with a space group of P63 /mmc, which is called the MgZn2-type (C14) structure belonging to the famous family of Laves phases. The calculated lattice constants a and c are 0.6427(4) and 1.043(6) nm, respectively. From the magnetic susceptibility measurement, KSn2 shows a superconducting transition at around 3.2 K.

Miyazaki, Shota; Kawashima, Kenji; Ipponjima, Tsukasa; Fukuma, Michinori; Hyakumura, Daiki; Akimitsu, Jun; Yoshikawa, Masaaki

2013-08-01

201

Fine structural details of human muscle fibres after fibre type specific glycogen depletion.  

Science.gov (United States)

Type 1 and Type 2 fibres of skeletal muscle (human m. vastus lateralis), selectively depleted of glycogen by sustained submaximal muscular exercise (running 30 km), were identified at light and electron microscopical level by examination of thin and ultra-thin serial sections treated particularly for visualization of glycogen. Averaged images, obtained by lateral smearing of depleted fibres (Type 1) exhibited five clearly visible cross-bridges in the M-band and had broad Z-bands. Non-depleted fibres (Type 2) showed either three central strong and two weak outer lines in the M-band and intermediate Z-bands (Type 2A), or only three central strong lines in the M-band and narrow Z-bands (Type 2B). The depleted fibres had no subsarcolemmal accumulation of glycogen particles and practically no intermyofibrillar particles. The remaining particles were small in size and seemed almost rudimentary. In non-exercised individuals, a peculiar distribution of individual glycogen particles in the I-band and A-band was found. This distribution was accounted by the structural arrangement of the myofibrillar material. PMID:7166509

Sjöström, M; Fridén, J; Ekblom, B

1982-01-01

202

Superconductivity in the Ternary Boride Cr2Re3B with the ?-Mn-Type Structure  

Science.gov (United States)

We report the superconducting properties of a new intermetallic superconductor, Cr2Re3B. Cr2Re3B has a cubic structure called the ?-Mn-type structure with the space group P4132 (No. 213), and shows a superconducting transition at around Tc = 4.8 K. The magnetization curve shows a typical type-II superconducting behavior. The estimated superconducting parameters of lower and upper critical fields, coherence length ?(0), penetration depth ?(0), and Ginzburg–Landau (GL) parameter ?(0), determined using GL relations, are about Hc1(0) = 52 Oe, Hc2(0) = 100 kOe, ?(0) = 356 nm, ?(0) = 5.7 nm, and ?(0) = 62.5, respectively. The specific heat data indicates that the superconductivity in Cr2Re3B can be described in the BCS theory. Finally, we discuss the superconducting state of Cr2Re3B using the determined parameters.

Niimura, Haru; Kawashima, Kenji; Inoue, Keigo; Yoshikawa, Masaaki; Akimitsu, Jun

2014-04-01

203

New-Type Phase Transition of Li2RuO3 with Honeycomb Structure  

Science.gov (United States)

A new-type structural transition has been found in Li2RuO3 with a honeycomb lattice of edge-sharing RuO6 octahedra. With decreasing temperature T, the electrical resistivity exhibits an anomalous increase at T=Tc ˜ 540 K, suggesting the (metal-to-insulator)-like transition, and the magnetic susceptibility also shows a sharp decrease. Detailed structure analyses have revealed that the high-temperature space group C2/m changes to P21/m at Tc. The most striking fact is that a significant reduction of the bond lengths is found between two of the six Ru-Ru pairs of the hexagon in the low-temperature phase, indicating a new-type phase transition driven by the formation of the molecular orbits of these Ru-Ru pairs.

Miura, Yoko; Yasui, Yukio; Sato, Masatoshi; Igawa, Naoki; Kakurai, Kazuhisa

2007-03-01

204

New Type Phase Transition of Li2RuO3 with Honeycomb Structure  

CERN Document Server

A new-type structural transition has been found in Li2RuO3 with honeycomb lattice of edge-sharing RuO6-octahedra. With decreasing temperature T, the electrical resistivity exhibits an anomalous increase at T=Tc~540 K, suggesting the (metal to insulator)-like transition and the magnetic susceptibility also shows a sharp decrease. Detailed structure analyses have revealed that the high temperature space group C2/m changes to P21/m at Tc. The most striking fact is that a significant reduction of the bond lengths is found between two of six Ru-Ru pairs of the hexagon in the low temperature phase, indicating a new type phase transition by the mechanism of the formation of molecular orbits of these Ru-Ru pairs.

Miura, Y; Sato, M; Igawa, N; Kakurai, K; Miura, Yoko; Yasui, Yukio; Sato, Masatoshi; Igawa, Naoki; Kakurai, Kazuhisa

2006-01-01

205

Peculiar reflections in diffraction patterns as indicators of structural type and quality  

Science.gov (United States)

Reflections serving as indicators of the types of packets forming crystal structures of many layered semiconductors have been revealed in diffraction patterns. It is found that the values l for the strongest reflection in series 000 l and 00 l, as well as the next to the strongest reflection in series ( h = const) and 0 kl ( k = const) for hexagonal and monoclinic structures, respectively, determine the number of polyhedral (Tand O) cation-filled layers per cell and indicate the types of packets TOT , , , , and OOE , where T and are inversely oriented tetrahedra, O is an octahedron, E is an empty interpacket layer, and E1 and E2 are partially filled (to less than 1/3) interpacket layers.

Kyazumov, M. G.

2014-09-01

206

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 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.

O.G.Vlokh

2000-09-01

207

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

OpenAIRE

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 ...

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

2012-01-01

208

Multi-scale (FE2) analysis of material failure in cement/aggregate-type composite structures  

OpenAIRE

The work propases a FP multiscale approach to computational modeling of material failure in concreteMlike structures, made of cement/aggregate-type composite materials. Keeping the approach in a classical homogenization setting, a multiscale model is proposed, which naturally provides a microscopic length-scale to be exported to the macrostructure. There, this length scale is used as regularization parameter in the context of the Continuum Strong Discontinuity Approach to material failure, an...

Oliver Olivella, Xavier; Caicedo, Manuel Alejandro; Roubin, Emmanuel; Herna?ndez Ortega, Joaqui?n Alberto; Huespe, Alfredo Edmundo

2014-01-01

209

Quaternary Structure and Functional Unit of Energy Coupling Factor (ECF)-type Transporters*  

OpenAIRE

ATP-binding cassette (ABC) transporters mediate transport of diverse substrates across membranes. We have determined the quaternary structure and functional unit of the recently discovered ECF-type (energy coupling factor) of ABC transporters, which is widespread among prokaryotes. ECF transporters are protein complexes consisting of a conserved energizing module (two peripheral ATPases and the integral membrane protein EcfT) and a non-conserved integral membrane protein responsible for subst...

Ter Beek, Josy; Duurkens, Ria H.; Erkens, Guus B.; Slotboom, Dirk Jan

2010-01-01

210

Structure-based mutagenesis of the catalytic domain of human immunodeficiency virus type 1 integrase.  

OpenAIRE

Two different crystal structures of the human immunodeficiency virus type 1 (HIV-1) integrase (IN) catalytic domain were analyzed for interactions at the enzyme active site. Gln-62 and Glu-92 interact with active-site residue Asp-64, and Lys-136 interacts with active-site residue Asp-116 across a dimer interface. Conservative and nonconservative substitutions were introduced at these positions to probe the roles of these interactions in HIV-1 integration. Purified mutant proteins were assayed...

Engelman, A.; Liu, Y.; Chen, H.; Farzan, M.; Dyda, F.

1997-01-01

211

Efficiency of different forest types in carbon storage depends on their internal structure  

OpenAIRE

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 produ...

Gheorghe, Iuliana F.; Biris?, Iovu A.; Valcu, Cristina M.

2010-01-01

212

Structure and mechanism of Zn(2+)-transporting P-type ATPases  

DEFF Research Database (Denmark)

Zinc is an essential micronutrient for all living organisms. It is required for signalling and proper functioning of a range of proteins involved in, for example, DNA binding and enzymatic catalysis. In prokaryotes and photosynthetic eukaryotes, Zn(2+)-transporting P-type ATPases of class IB (ZntA) are crucial for cellular redistribution and detoxification of Zn(2+) and related elements. Here we present crystal structures representing the phosphoenzyme ground state (E2P) and a dephosphorylation intermediate (E2·Pi) of ZntA from Shigella sonnei, determined at 3.2 Å and 2.7 Å resolution, respectively. The structures reveal a similar fold to Cu(+)-ATPases, with an amphipathic helix at the membrane interface. A conserved electronegative funnel connects this region to the intramembranous high-affinity ion-binding site and may promote specific uptake of cellular Zn(2+) ions by the transporter. The E2P structure displays a wide extracellular release pathway reaching the invariant residues at the high-affinity site, including C392, C394 and D714. The pathway closes in the E2·Pi state, in which D714 interacts with the conserved residue K693, which possibly stimulates Zn(2+) release as a built-in counter ion, as has been proposed for H(+)-ATPases. Indeed, transport studies in liposomes provide experimental support for ZntA activity without counter transport. These findings suggest a mechanistic link between PIB-type Zn(2+)-ATPases and PIII-type H(+)-ATPases and at the same time show structural features of the extracellular release pathway that resemble PII-type ATPases such as the sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase (SERCA) and Na(+), K(+)-ATPase. These findings considerably increase our understanding of zinc transport in cells and represent new possibilities for biotechnology and biomedicine.

Wang, Kaituo; Sitsel, Oleg

2014-01-01

213

New phosphides of the Nb4CoSi type structure  

International Nuclear Information System (INIS)

For the first time stated is the formation of Hf4FeP, Hf4CoP and TaFeP phosphides having the Nb4CoSi type structure. Binary intermetallic compounds TaCo, Ta2Ni, Zr2Co, Zr2Ni, Hf2Ni are shown to disslove up to 17 at.% P. Maximum composition of these solid solutions is characterized by ordered distribution of Co(or Ni)and P atoms

214

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

OpenAIRE

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 (60?70 %), which were effected by hydrochloric...

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

2004-01-01

215

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

OpenAIRE

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 cons...

Vlokh, O. G.

2000-01-01

216

The reproducing kernel structure associated to Fourier type systems and their quantum analogues  

OpenAIRE

We study mapping properties of operators with kernels defined via an abstract formulation of quantum (q-) Fourier type systems. We prove Ismail´s conjecture regarding the existence of a reproducing kernel structure behind these kernels. The results are illustrated with Fourier kernels with ultraspherical and Jacobi weights, their continuous q-extensions and generalizations. As a byproduct of this approach, a new class of sampling theorems is obtained, as well as Neumann typ...

Abreu, Lui?s Daniel

2005-01-01

217

Structure of the minor pseudopilin XcpW from the Pseudomonas aeruginosa type II secretion system  

Energy Technology Data Exchange (ETDEWEB)

Pseudomonas aeruginosa utilizes the type II secretion machinery to transport virulence factors through the outer membrane into the extracellular space. Five proteins in the type II secretion system share sequence homology with pilin subunits of type IV pili and are called the pseudopilins. The major pseudopilin X{sub cp}T{sub G} assembles into an intraperiplasmic pilus and is thought to act in a piston-like manner to push substrates through an outer membrane secretin. The other four minor pseudopilins, X{sub cp}U{sub H}, X{sub cp}V{sub I}, X{sub cp}W{sub J} and X{sub cp}X{sub K}, play less well defined roles in pseudopilus formation. It was recently discovered that these four minor pseudopilins form a quaternary complex that is presumed to initiate the formation of the pseudopilus and to localize to its tip. Here, the structure of X{sub cp}W{sub J} was refined to 1.85 {angstrom} resolution. The structure revealed the type IVa pilin fold with an embellished variable antiparallel {beta}-sheet as also found in the X{sub cp}W{sub J} homologue enterotoxigenic Escherichia coli G{sub sp}J{sub W} and the X{sub cp}U{sub H} homologue Vibrio cholerae E{sub ps}U{sub H}. It is proposed that the exposed surface of this sheet may cradle the long N-terminal 1 helix of another pseudopilin. The final 31 amino acids of the X{sub cp}W{sub J} structure are instrinsically disordered. Deletion of this unstructured region of X{sub cp}W{sub J} did not prevent type II secretion in vivo.

Franz, Laura P.; Douzi, Badreddine; Durand, Eric; Dyer, David H.; Voulhouxd, Romé; Forest, Katrina T. (CNRS-UMR); (CNRS-CRMD); (UW)

2012-01-13

218

Human T-lymphotropic virus type 1 non-structural proteins: Requirements for latent infection.  

Science.gov (United States)

It has been more than 30 years since the discovery of human T-lymphotropic virus type 1 (HTLV-1), the first human retrovirus identified. Human T-lymphotropic virus type 1 infects 15-20 million people worldwide causing two major diseases: adult T-cell leukemia/lymphoma and HTLV-1-associated myelopathy/tropical spastic paraparesis. Human T-lymphotropic virus type 1 establishes several decades of latent infection, during which viral-host interaction determines disease segregation. This review highlights non-structural proteins that are encoded on the viral genome and manage latent infection. Latent infection is a key in HTLV pathology, so that effective inhibition of these proteins might lead to successful disease management. PMID:23651172

Fukumoto, Risaku

2013-08-01

219

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

Energy Technology Data Exchange (ETDEWEB)

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.)

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

220

Identification of beat characteristics and damping ratios of bell type structures using wavelet transform  

Science.gov (United States)

The aim of this paper is to propose an effective method for extracting the beat characteristics and modal damping ratios of the bell type structures using the continuous wavelet transform (CWT). The bell type structures which can be simplified as a slightly asymmetric circular ring and cylindrical shell are commonly used to analyze those of a Korean bell. The beat response is caused by the mutual interference of mode pairs, which are created by the slight asymmetry of the bell type structures in the circumferential direction. First of all, the beat frequencies and periods of each vibration mode are obtained using the CWT based on the Gabor wavelet. Next, the modal damping ratios associated with the time duration of the beat response are also extracted by the CWT. When using the CWT on a given signal, the optimal shape of the Gabor wavelet used as the mother wavelet is determined by employing the Shannon entropy cost function on the normalized wavelet modulus. In order to show the accuracy of the proposed method, the beat characteristics and damping ratios are extracted from the simulated pure and noisy signals, which have mode pairs. Finally, the proposed method is applied to a small-sized Korean bell to verify its applicability in the field.

Park, Sung Yong; Kang, Yeon June; Kim, Seock Hyun

2009-09-01

221

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2009-05-20

222

The relationship analysis of thrust structure and sandstone type uranium deposits at northern margin of qaidam basin  

International Nuclear Information System (INIS)

The thrust belt at northern margin of the Qaidam basin is prospective area for finding sandstone-type uranium deposits. The structure is complicated, post-reformation is strong and thrust structure develops in this area. Single thrust structure, opposite thrust structure, recoil structure and slope zone are the most common structural patterns. The different of tectonic style causes differences in occurrence and thickness of sedimentary strata and effects the metallogenic environment of sandstone-type uranium deposits. By analyzing the different between the tectonic style and uranium mineralization, it shows that uranium prospecting works deployment vary with the different of thrust tectonic styles. (authors)

223

Cybernetic preductoon of AB2Ge2 composition germanides with ThCr2Si2 type crystal structure  

International Nuclear Information System (INIS)

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

224

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

DEFF Research Database (Denmark)

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 every time in the early phase of ELM. It seems like a quick transitional stage between edge localized mode (MHD) phase and transport phase during the ELM. A pronounced sinusoidal pattern has been observed on the radial magnetic induction signal by Langmuir - magnetic probe, corresponding with almost a 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 crash. As current structure can only be observed in far SOL region of EAST, it maybe conceivable to consider the current origin from local condition rather than release from inside of the pedestal. Our observation may potentially provide support evidence for the recent theory prediction that the error led generated by scrape-off layer current can ultimately trigger the ELM through the coupling with MHD modes inside the separatrix.

Yan, Ning; Naulin, Volker

225

Moessbauer study of two different aged rock types in the Vredefort structure, South Africa  

International Nuclear Information System (INIS)

The Vredefort Structure in South Africa was recently inscribed into the list of World Heritage sites as the oldest and largest recognised impact structure on earth. Due to upliftment of more than 30 km of the Archaean basement core and subsequent exposure of the deeply eroded central portion of the crater a unique opportunity exists to study rocks of the crust, especially those that have undergone recrystallization due to various thermal metamorphic events over time. Two rock types occurring in the central uplifted part of the impact structure were studied. One was a typical Archaean iron formation of sedimentary origin. The other rock studied, adjacent to this much older rock, is a homogeneous, medium grained recrystallized norite of immediately pre- or post-impact age, indicating a possible mafic igneous activity related to impact. Microscopy, XRD and Moessbauer analyses were performed on both samples.

226

Moessbauer study of two different aged rock types in the Vredefort structure, South Africa  

Energy Technology Data Exchange (ETDEWEB)

The Vredefort Structure in South Africa was recently inscribed into the list of World Heritage sites as the oldest and largest recognised impact structure on earth. Due to upliftment of more than 30 km of the Archaean basement core and subsequent exposure of the deeply eroded central portion of the crater a unique opportunity exists to study rocks of the crust, especially those that have undergone recrystallization due to various thermal metamorphic events over time. Two rock types occurring in the central uplifted part of the impact structure were studied. One was a typical Archaean iron formation of sedimentary origin. The other rock studied, adjacent to this much older rock, is a homogeneous, medium grained recrystallized norite of immediately pre- or post-impact age, indicating a possible mafic igneous activity related to impact. Microscopy, XRD and Moessbauer analyses were performed on both samples.

Waanders, F. B., E-mail: chifbw@puk.ac.za; Brink, M. C.; Bisschoff, A. A. [North-west University, School of Chemical and Minerals Engineering (South Africa)

2005-11-15

227

Structural features and superconductivity of Al-doped Y(RE)-123-type single crystals  

International Nuclear Information System (INIS)

The structure of a series of highly Al-doped superconducting Y(RE)-123 (RE = rare earth element) single crystals was investigated by XRD and NMR methods. On the basis of the data obtained by the structural investigations combined with the studies of magnetic and optical properties, the formation of various superstructures in the samples of pseudo-tetragonal symmetry has been discussed. The correlation between the carrier concentration and Tc-values has been determined. The superconductivity (at 70 K) was indicated even at the 2/3 and 1/3 Al substitution for Cu in the basal and CuO2 planes, respectively, in the phase presumably of a perovskite-like structural type. (author)

228

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

CERN Document Server

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.

Gorban, A N; Zinovyev, A Yu

2011-01-01

229

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

International Nuclear Information System (INIS)

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

230

Sloshing and fluid-structure interaction in a 400-MWe pool-type advanced LMR reactor  

International Nuclear Information System (INIS)

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 to the fast reactor system

231

Identification, biochemical and structural evaluation of species-specific inhibitors against type I methionine aminopeptidases.  

Science.gov (United States)

Methionine aminopeptidases (MetAPs) are essential enzymes that make them good drug targets in cancer and microbial infections. MetAPs remove the initiator methionine from newly synthesized peptides in every living cell. MetAPs are broadly divided into type I and type II classes. Both prokaryotes and eukaryotes contain type I MetAPs, while eukaryotes have additional type II MetAP enzyme. Although several inhibitors have been reported against type I enzymes, subclass specificity is scarce. Here, using the fine differences in the entrance of the active sites of MetAPs from Mycobacterium tuberculosis , Enterococcus faecalis , and human, three hotspots have been identified and pyridinylpyrimidine-based molecules were selected from a commercial source to target these hotspots. In the biochemical evaluation, many of the 38 compounds displayed differential behavior against these three enzymes. Crystal structures of four selected inhibitors in complex with human MetAP1b and molecular modeling studies provided the basis for the binding specificity. PMID:23767698

Kishor, Chandan; Arya, Tarun; Reddi, Ravikumar; Chen, Xiaochun; Saddanapu, Venkateshwarlu; Marapaka, Anil Kumar; Gumpena, Rajesh; Ma, Dawei; Liu, Jun O; Addlagatta, Anthony

2013-07-11

232

THE SLACS SURVEY. VIII. THE RELATION BETWEEN ENVIRONMENT AND INTERNAL STRUCTURE OF EARLY-TYPE GALAXIES  

International Nuclear Information System (INIS)

We study the relation between the internal structure of early-type galaxies and their environment using 70 strong gravitational lenses from the SLACS Survey. The Sloan Digital Sky Survey (SDSS) database is used to determine two measures of overdensity of galaxies around each lens-the projected number density of galaxies inside the tenth nearest neighbor (?10) and within a cone of radius one h-1 Mpc (D 1). Our main results are as follows. (1) The average overdensity is somewhat larger than unity, consistent with lenses preferring overdense environments as expected for massive early-type galaxies (12/70 lenses are in known groups/clusters). (2) The distribution of overdensities is indistinguishable from that of 'twin' nonlens galaxies selected from SDSS to have the same redshift and stellar velocity dispersion ?*. Thus, within our errors, lens galaxies are an unbiased population, and the SLACS results can be generalized to the overall population of early-type galaxies. (3) Typical contributions from external mass distribution are no more than a few percent in local mass density, reaching 10-20% (?0.05-0.10 external convergence) only in the most extreme overdensities. (4) No significant correlation between overdensity and slope of the mass-density profile of the lens galaxies is found. (5) Satellite galaxies (those with a more luminous companion) have marginally steeper mass-density profiles (as quantified by f SIESIE = ?*/?SIE = 1.12 ± 0.05 versus 1.01 ± 0.01) and smaller dynamically normalized mass enclosed within the Einstein radius (?log M Ein/M dim differs by -0.09 ± 0.03 dex) than central galaxies (those without). This result suggests that tidal stripping may affect the mass structure of early-type galaxies down to kpc scales probed by strong lensing, when they fall into larger structures.

233

Pressure-induced phase transition of SmBi with a NaCl-type structure  

Energy Technology Data Exchange (ETDEWEB)

By use of synchrotron radiation, powder x-ray diffraction of SmBi with a NaCl-type structure has been studied up to 30 GPa at room temperature. A first-order phase transition began to occur at around 16.2 GPa. SmBi transformed from the NaCl-type (B1) to the tetragonal (distorted CsCl-type) structure with the volume collapse of about 8.2 % at around 18.3 GPa. Crystal data of the single phase are a = 3.775(5) A, c = 3.25 (2) A, c/a = 0.86 and V = 46.4 (3) A{sup 3} at 20.3 GPa. The high-pressure form of SmBi is isostructural with that of SmAs. A bulk modulus of SmBi was estimated from the volume vs. pressure curve fitted by a Birch equation of state. The bulk modulus (B{sub 0}) and its pressure derivative (B{sub 0}') are 68 {+-} 3 GPa and 3.9 {+-} 0.3, respectively. The transition pressure and the bulk modulus of SmBi are larger than those of CeBi and PrBi. The structural high-pressure behaviour for SmX (X = P, As, Sb and Bi) is discussed. The structural phase transition of LaBi and NdBi occurred at around 11.5 GPa and 16.8 GPa, respectively. The transition pressures of LnBi (Ln = La, Ce, Pr, Nd and Sm) decreased with increasing lattice constant.

Hayashi, J; Toyama, T; Takeda, K; Shirotani, I [Muroran Institute of Technology, 27-1, Mizumoto, Muroran-shi 050-8585 (Japan); Ohishi, Yasuo, E-mail: ichimin-s302@diary.ocn.ne.j [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto Mikazuki-cho Sayo-gun 679-5198 (Japan)

2010-03-01

234

Pressure-induced phase transition of SmBi with a NaCl-type structure  

International Nuclear Information System (INIS)

By use of synchrotron radiation, powder x-ray diffraction of SmBi with a NaCl-type structure has been studied up to 30 GPa at room temperature. A first-order phase transition began to occur at around 16.2 GPa. SmBi transformed from the NaCl-type (B1) to the tetragonal (distorted CsCl-type) structure with the volume collapse of about 8.2 % at around 18.3 GPa. Crystal data of the single phase are a = 3.775(5) A, c = 3.25 (2) A, c/a = 0.86 and V = 46.4 (3) A3 at 20.3 GPa. The high-pressure form of SmBi is isostructural with that of SmAs. A bulk modulus of SmBi was estimated from the volume vs. pressure curve fitted by a Birch equation of state. The bulk modulus (B0) and its pressure derivative (B0') are 68 ± 3 GPa and 3.9 ± 0.3, respectively. The transition pressure and the bulk modulus of SmBi are larger than those of CeBi and PrBi. The structural high-pressure behaviour for SmX (X = P, As, Sb and Bi) is discussed. The structural phase transition of LaBi and NdBi occurred at around 11.5 GPa and 16.8 GPa, respectively. The transition pressures of LnBi (Ln = La, Ce, Pr, Nd and Sm) decreased with increasing lattice constant.

235

Pressure-induced phase transition of SmBi with a NaCl-type structure  

Science.gov (United States)

By use of synchrotron radiation, powder x-ray diffraction of SmBi with a NaCl-type structure has been studied up to 30 GPa at room temperature. A first-order phase transition began to occur at around 16.2 GPa. SmBi transformed from the NaCl-type (B1) to the tetragonal (distorted CsCl-type) structure with the volume collapse of about 8.2 % at around 18.3 GPa. Crystal data of the single phase are a = 3.775(5) Å, c = 3.25 (2) Å, c/a = 0.86 and V = 46.4 (3) Å3 at 20.3 GPa. The high-pressure form of SmBi is isostructural with that of SmAs. A bulk modulus of SmBi was estimated from the volume vs. pressure curve fitted by a Birch equation of state. The bulk modulus (B0) and its pressure derivative (B0') are 68 ± 3 GPa and 3.9 ± 0.3, respectively. The transition pressure and the bulk modulus of SmBi are larger than those of CeBi and PrBi. The structural high-pressure behaviour for SmX (X = P, As, Sb and Bi) is discussed. The structural phase transition of LaBi and NdBi occurred at around 11.5 GPa and 16.8 GPa, respectively. The transition pressures of LnBi (Ln = La, Ce, Pr, Nd and Sm) decreased with increasing lattice constant.

Hayashi, J.; Toyama, T.; Takeda, K.; Shirotani, I.; Ohishi, Yasuo

2010-03-01

236

Structure and function of the adhesive type IV pilus of Sulfolobus acidocaldarius.  

Science.gov (United States)

Archaea display a variety of type IV pili on their surface and employ them in different physiological functions. In the crenarchaeon Sulfolobus acidocaldarius the most abundant surface structure is the aap pilus (archaeal adhesive pilus). The construction of in frame deletions of the aap genes revealed that all the five genes (aapA, aapX, aapE, aapF, aapB) are indispensible for assembly of the pilus and an impact on surface motility and biofilm formation was observed. Our analyses revealed that there exists a regulatory cross-talk between the expression of aap genes and archaella (formerly archaeal flagella) genes during different growth phases. The structure of the aap pilus is entirely different from the known bacterial type IV pili as well as other archaeal type IV pili. An aap pilus displayed 3 stranded helices where there is a rotation per subunit of ?138° and a rise per subunit of ?5.7?Å. The filaments have a diameter of ?110?Å and the resolution was judged to be ?9?Å. We concluded that small changes in sequence might be amplified by large changes in higher-order packing. Our finding of an extraordinary stability of aap pili possibly represents an adaptation to harsh environments that S.?acidocaldarius encounters. PMID:23078543

Henche, Anna-Lena; Ghosh, Abhrajyoti; Yu, Xiong; Jeske, Torsten; Egelman, Edward; Albers, Sonja-Verena

2012-12-01

237

A multilocus sequence typing scheme implies population structure and reveals several putative novel Achromobacter species.  

Science.gov (United States)

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 genus-level multilocus sequence typing (MLST) scheme. We employed in silico analyses of whole-genome sequences of several phylogenetically related genera, including Bordetella, Burkholderia, Cupriavidus, Herminiimonas, Janthinobacterium, Methylibium, and Ralstonia, for selecting loci and designing PCR primers. Using this MLST scheme, we analyzed 107 genetically diverse Achromobacter isolates cultured from biologic specimens from CF and non-CF patients, 1 isolate recovered from sludge, and an additional 39 strains obtained from culture collections. Sequence data from these 147 strains, plus three recently genome-sequenced Achromobacter strains, were assigned to 129 sequence types based on seven loci. Calculation of the nucleotide divergence of concatenated locus sequences within and between MLST clusters confirmed the seven previously named Achromobacter species and revealed 14 additional genogroups. Indices of association showed significant linkage disequilibrium in all of the species/genogroups able to be tested, indicating that each group has a clonal population structure. No clear segregation of species/genogroups between CF and non-CF sources was found. PMID:22785192

Spilker, Theodore; Vandamme, Peter; Lipuma, John J

2012-09-01

238

Structure of the Type IVa Major Pilin from the Electrically Conductive Bacterial Nanowires of Geobacter sulfurreducens  

Energy Technology Data Exchange (ETDEWEB)

Several species of bacteria are capable of reducing insoluble metal oxides as well as other extracellular electron acceptors. These bacteria play a critical role in the cycling of minerals in subsurface environments, sediments, and groundwater. In some species of bacteria, such as Geobacter sulfurreducens, the transport of electrons is facilitated by filamentous fibers that are referred to as bacterial nanowires. These nanowires belong to the type IVa family of pilin proteins and are mainly comprised of one subunit protein, PilA. Here, we report the high resolution solution nuclear magnetic resonance (NMR) structure of the PilA protein from G. sulfurreducens determined in detergent micelles. The protein is over 85% ?-helical and exhibits similar architecture to the N-terminal regions of other non-conductive type IVa pilins. The detergent micelle interacts with the first 21 amino acids of the protein, indicating that this region likely associates with the bacterial inner membrane prior to fiber formation. A model of the G. sulfurreducens pilus fiber is proposed based on docking of this structure into the fiber model of the type IVa pilin from Neisseria gonorrhoeae. This model provides insight into the organization of aromatic amino acids that are important for electrical conduction.

Reardon, Patrick N.; Mueller, Karl T.

2013-10-11

239

Thermoelectric properties and micro-structure characteristics of annealed N-type bismuth telluride thin film  

International Nuclear Information System (INIS)

N-type bismuth telluride (Bi2Te3) thermoelectric thin films were deposited by co-sputtering simple substance Te and Bi targets. The deposited films were annealed under various temperatures. The composition ratio, micro-structure and thermoelectric properties of the prepared films were systematically investigated by energy dispersive spectrometer, X-ray diffraction, four-probe method and Seebeck coefficient measurement system. When the annealing temperature is 400 °C, the stoichiometric N-type Bi2Te3 film is achieved, which has a maximum thermoelectric power factor of 0.821 × 10?3 W m?1 K?2. Furthermore, the dependence of Seebeck coefficient, electrical conductivity and power factor of the stoichiometric N-type Bi2Te3 film annealed at film 400 °C on the applied temperature ranging from 25 °C to 315 °C was investigated. The results show that a highest power factor of 3.288 × 10?3 W m?1 K?2 is obtained at the applied temperature of 275 °C. The structural and thermoelectric properties of the deposited bismuth telluride thin films are greatly improved by annealing and the Seebeck coefficient, electrical conductivity and power factor increase with the applied temperature rising, which are helpful and could be guidance for preparing the high-performance thin film thermoelectric materials for thermoelectric application.

240

The structure of experience, the nature of the visual, and type 2 blindsight.  

Science.gov (United States)

Unlike those with type 1 blindsight, people who have type 2 blindsight have some sort of consciousness of the stimuli in their blind field. What is the nature of that consciousness? Is it visual experience? I address these questions by considering whether we can establish the existence of any structural-necessary-features of visual experience. I argue that it is very difficult to establish the existence of any such features. In particular, I investigate whether it is possible to visually, or more generally perceptually, experience form or movement at a distance from our body, without experiencing colour. The traditional answer, advocated by Aristotle, and some other philosophers, up to and including the present day, is that it is not and hence colour is a structural feature of visual experience. I argue that there is no good reason to think that this is impossible, and provide evidence from four cases-sensory substitution, achomatopsia, phantom contours and amodal completion-in favour of the idea that it is possible. If it is possible then one important reason for rejecting the idea that people with type 2 blindsight do not have visual experiences is undermined. I suggest further experiments that could be done to help settle the matter. PMID:25481513

Macpherson, Fiona

2015-03-01

241

Physcomitrella HMGA-type proteins display structural differences compared to their higher plant counterparts  

International Nuclear Information System (INIS)

High mobility group (HMG) proteins of the HMGA family are chromatin-associated proteins that act as architectural factors in nucleoprotein structures involved in gene transcription. To date, HMGA-type proteins have been studied in various higher plant species, but not in lower plants. We have identified two HMGA-type proteins, HMGA1 and HMGA2, encoded in the genome of the moss model Physcomitrella patens. Compared to higher plant HMGA proteins, the two Physcomitrella proteins display some structural differences. Thus, the moss HMGA proteins have six (rather than four) AT-hook DNA-binding motifs and their N-terminal domain lacks similarity to linker histone H1. HMGA2 is expressed in moss protonema and it localises to the cell nucleus. Typical of HMGA proteins, HMGA2 interacts preferentially with A/T-rich DNA, when compared with G/C-rich DNA. In cotransformation assays in Physcomitrella protoplasts, HMGA2 stimulated reporter gene expression. In summary, our data show that functional HMGA-type proteins occur in Physcomitrella

242

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  

Directory of Open Access Journals (Sweden)

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.

Elahi-Moghaddam Zohreh

2013-01-01

243

Corrosion preventing method for BWR type reactor and structural material thereof  

International Nuclear Information System (INIS)

In a method of preventing corrosion, for moderating a corrosion circumstance of reactor structural components by injection of hydrogen while suppressing transfer of 16N into a turbine system, an electrode is disposed in reactor water, a potential difference between the electrode and the reactor core structural materials is controlled as required, and the potential of the reactor core structural materials is reduced to -230mV or lower based on a standard hydrogen electrode potential reference. A value of a current flowing between the reactor structural materials and the metal electrode can be controlled by applying voltage, so that the dose rate of a turbine building can be controlled. The corrosion circumstance of the reactor structural materials can be moderated, which would be difficult by hydrogen injection, by using a Galvani method and a combination of the Galvani method and a compulsory charging method. Accordingly, corrosion of the reactor core in a BWR type reactor which is exposed to the severest corrosion circumstance can be reduced while suppressing the amount of radioactivity in pipelines of a main steam system and a turbine system and also suppressing dose rate at the boundary of the site, thereby enabling to remarkably improve reactor integrity and safety. (N.H.)

244

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

Science.gov (United States)

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 influences these electronic states. The studied orthovanadates, 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 shows 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.

Panchal, V.; Errandonea, D.; Segura, A.; Rodríguez-Hernandez, P.; Muñoz, A.; Lopez-Moreno, S.; Bettinelli, M.

2011-08-01

245

Flow structure of water in carbon nanotubes: Poiseuille type or plug-like?  

Science.gov (United States)

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 100m/s. 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 300m/s 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.

Hanasaki, Itsuo; Nakatani, Akihiro

2006-04-01

246

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

CERN Document Server

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.

Panchal, V; Segura, A; Rodriguez-Hernandez, P; Munoz, A; Lopez-Moreno, S; Bettinelli, M; 10.1063/1.3626060

2012-01-01

247

Study on the seismic response of a reactor vessel of a pool type LMFBR including fluid-structure interaction  

International Nuclear Information System (INIS)

The pool type LMFBR reactor vessel contains many structures and a large amount of liquid sodium in it, in addition to being a thin shell structure. Therefore, the fluid-structure interaction will become more predominant, and then should be considered for the seismic design of the pool type LMFBR. We investigated the fluid-structure interaction problems of the reactor vessel which has a bottom support arrangement as the core support system, in addition to the sloshing characteristics in the reactor vessel. The experimental results and the analytical results by FEM which account for the interaction between fluid and structures are presented. (orig.)

248

From Proteomics to Structural Studies of Cytosolic/Mitochondrial-Type Thioredoxin Systems in Barley Seeds  

DEFF Research Database (Denmark)

Thioredoxins (Trx) are ubiquitous proteins that participate in thiol disulfide reactions via two active site cysteine residues, allowing Trx to reduce disulfide bonds in target proteins. Recent progress in proteome analysis has resulted in identification of a wide range of potential target proteins for Trx, indicating that Trx plays a key role in several aspects of cell metabolism. In contrast to other organisms, plants contain multiple forms of Trx that are classified based on their primary structures and sub-cellular localization. The reduction of cytosolic and mitochondrial types of Trx is dependent on NADPH and catalyzed by NADPH-dependent thioredoxin reductase (NTR). In barley, two isoforms each of Trx and NTR have been identified and investigated using proteomics, gene expression, and structural studies. This review outlines the diverse roles suggested for cytosolic/mitochondrial-type Trx systems in cereal seeds and summarizes the current knowledge of the barley system including recent data on function,regulation, interactions, and structure. Directions for future research are discussed.

Shahpiri, Azar; Svensson, Birte

2009-01-01

249

Crystal structure of a novel cysteinless plant Kunitz-type protease inhibitor  

International Nuclear Information System (INIS)

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 ?-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

250

A study on structural changes in protein by time-division type Laue method  

International Nuclear Information System (INIS)

In order to know the physiological roles of proteins, it is important to investigate the intermediate states of their structural changes. The sizes of proteins are generally several tens angstrom(A). Considering the resolution, only x-ray crystal analysis can be used in practice for the investigation of the mechanism of protein structural changes, though NMR is applicable only for small-sized proteins. However, x-ray analysis is not so suitable for analysis of their intermediate states. Thus, the author paid attention to the time-division type Laue method for the study of hemoglobin (Hb). Laser-flash induces to release carbonmonooxide (CO) from carboxyhemoglobin (Hb(CO)4). Therefore, if an appropriate length of x-ray pulse (?100 picosec) is available, the processes in the period from cleavage of the bond between a ligand (O2, CO or NO) and Hb to recombination of them might be monitored. Using DNA recombination and chemical modification techniques, recombinant Hb, of which T structure is stable was produced. An investigation on the conditions which allow to release CO from the Hb is undertaken using a single crystal of this Hb. The experimental systems applicable to time-division type Laue method are some protein molecules participating in chemical reactions inducible by light absorption, the electron-transfer system excited by light and so on. (M.N.)

251

Gene duplication of type-B ARR transcription factors systematically extends transcriptional regulatory structures in Arabidopsis.  

Science.gov (United States)

Many of duplicated genes are enriched in signaling pathways. Recently, gene duplication of kinases has been shown to provide genetic buffering and functional diversification in cellular signaling. Transcription factors (TFs) are also often duplicated. However, how duplication of TFs affects their regulatory structures and functions of target genes has not been explored at the systems level. Here, we examined regulatory and functional roles of duplication of three major ARR TFs (ARR1, 10, and 12) in Arabidopsis cytokinin signaling using wild-type and single, double, and triple deletion mutants of the TFs. Comparative analysis of gene expression profiles obtained from Arabidopsis roots in wild-type and these mutants showed that duplication of ARR TFs systematically extended their transcriptional regulatory structures, leading to enhanced robustness and diversification in functions of target genes, as well as in regulation of cellular networks of target genes. Therefore, our results suggest that duplication of TFs contributes to robustness and diversification in functions of target genes by extending transcriptional regulatory structures. PMID:25425016

Choi, Seung Hee; Hyeon, Do Young; Lee, Ll Hwan; Park, Su Jin; Han, Seungmin; Lee, In Chul; Hwang, Daehee; Nam, Hong Gil

2014-01-01

252

DYNAMICS AND CLASSIFICATION OF THE TYPES OF BUSINESS STRUCTURES IN CONSTRUCTION  

Directory of Open Access Journals (Sweden)

Full Text Available Entrepreneurs need information about a possible organizational and species diversity of enterprise structures, on the specific characteristics associated with each of their mind, about the advantages and disadvantages of multilevel business. To do this, society must be scientifically based unified classification of business structures. However, at present there is no such classification. In modern economic literature highlights only some aspects of group business structures, including construction.The most important classification features allow revealing the essential characteristics of business organizations in general, and in the construction sector of the economy, in particular. These characteristics should include: stakeholders and shape its organizational and legal reference; limits the liability of owners; form and subject of his own; nature of the control of the owner of capital resources; the involvement of stakeholders in the property; form of participation in the activities of the owner of the capital; level of implementation of the interests of the owners; type, legal status and the main objective of the enterprise structure; the use of hired labor.In 2013, in the construction industry of Russia operated 218, 0 thousand business structures, which functioned mainly on the basis of private ownership. The growth trend in the number of business organizations, which occurred during the period 2000-2013 years, characterized by overt instability. State socio-economic policy, the level of competition, structural changes in the economy, changes in production technologies, the mobility of funding, a way of doing construction work are the main factors that influence the dynamics of business structures in construction.

Alexander Aleksandrovich Halin

2015-03-01

253

Microbial community structure of ethanol type fermentation in bio-hydrogen production.  

Science.gov (United States)

Three continuous stirred-tank reactors (CSTRs) were used for H(2) production from molasses wastewater at influent pH of 6.0-6.5 (reactor A), 5.5-6.0 (reactor B), or 4.0-4.5 (reactor C). After operation for 28 days, the microbial community formed ethanol type (C), propionate type (A) and ethanol-butyrate-mixed type (B) fermentation. The H(2) production rate was the highest for ethanol type fermentation, 0.40 l (g VSS)(-1) day(-1) or 0.45 l H(2) (g COD removed)(-1). Microbial community dynamics and diversity were analysed using double-gradient denaturing gradient gel electrophoresis (DG-DGGE). Denaturing gradient gel electrophoresis profiles indicated that the community structures changed quickly in the first 14 days. Phylogenetic analysis indicated that the dominant bacterial groups were low G+C Gram-positive bacteria, Bacteroides, gamma-Proteobacteria and Actinobacteria; alpha-Proteobacteria, beta-Proteobacteria, delta-Proteobacteria and Spirochaetes were also presented as minor groups in the three reactors. H(2)-producing bacteria were affiliated with Ethanoligenens, Acetanaerobacterium, Clostridium, Megasphaera, Citrobacter and Bacteroides. An ethanol-based H(2)-producing bacterium, Ethanoligenens harbinense CGMCC1152, was isolated from reactor C and visualized using fluorescence in situ hybridization (FISH) to be 19% of the eubacteria in reactor C. In addition, isoenzyme activity staining for alcohol dehydrogenase (ADH) supported that the majority of ethanol-producing bacteria were affiliated with Ethanoligenens in the microbial community. PMID:17472628

Ren, Nanqi; Xing, Defeng; Rittmann, Bruce E; Zhao, Lihua; Xie, Tianhui; Zhao, Xin

2007-05-01

254

Kinetics of formation of twinned structures under L1_0 type orderings in alloys  

CERN Document Server

The earlier-developed master equation approach and kinetic cluster methods are applied to study kinetics of L1_0 type orderings in alloys, including the formation of twinned structures characteristic of cubic-tetragonal-type phase transitions. A microscopical model of interatomic deformational interactions is suggested which generalizes a similar model of Khachaturyan for dilute alloys to the physically interesting case of concentrated alloys. The model is used to simulate A1->L1_0 transformations after a quench of an alloy from the disordered A1 phase to the single-phase L1_0 state for a number of alloy models with different chemical interactions, temperatures, concentrations, and tetragonal distortions. We find a number of peculiar features in both transient microstructures and transformation kinetics, many of them agreeng well with experimental data. The simulations also demonstrate a phenomenon of an interaction-dependent alignment of antiphase boundaries in nearly-equilibrium twinned bands which seems to...

Belashchenko, K D; Samolyuk, G D; Vaks, V G

2001-01-01

255

Mechanical adaptability of the Bouligand-type structure in natural dermal armour  

Science.gov (United States)

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 scale’s ductility and toughness to prevent fracture.

Zimmermann, Elizabeth A.; Gludovatz, Bernd; Schaible, Eric; Dave, Neil K. N.; Yang, Wen; Meyers, Marc A.; Ritchie, Robert O.

2013-10-01

256

Function and Evolutionary Origin of Unicellular Camera-Type Eye Structure  

Science.gov (United States)

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. PMID:25734540

Hayakawa, Shiho; Takaku, Yasuharu; Hwang, Jung Shan; Horiguchi, Takeo; Suga, Hiroshi; Ikeo, Kazuho; Gojobori, Takashi

2015-01-01

257

Function and evolutionary origin of unicellular camera-type eye structure.  

Science.gov (United States)

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. PMID:25734540

Hayakawa, Shiho; Takaku, Yasuharu; Hwang, Jung Shan; Horiguchi, Takeo; Suga, Hiroshi; Gehring, Walter; Ikeo, Kazuho; Gojobori, Takashi

2015-01-01

258

Structural Characterization of Lignin in Wild-type versus COMT Down-regulated Switchgrass  

Directory of Open Access Journals (Sweden)

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.

ArthurRagauskas

2014-01-01

259

Thermoelectric and transport properties of sintered n-type K8Ba16Ga40Sn96 with type-II clathrate structure  

International Nuclear Information System (INIS)

This clathrate had a maximum dimensionless figure-of-merit, ZT, of 0.93 at 637?K, which was slightly higher than that of 0.83 for the sintered type-VIII clathrate Ba8Ga16Sn30. We investigated the high-temperature thermoelectric properties, transport properties, electronic structures, and thermal stabilities of the clathrates. The type-II clathrate was found to be superior to the type-VIII clathrate as a thermoelectric material; it had a high thermal stability and melting point, 859?K, high mobility, 141 cm2V?1s?1 at 300?K, because of its low inertial mass, and low high-temperature lattice thermal conductivity, approximately 4 mW cm?1K?1, resulting from a larger unit cell and weaker bipolar thermal conduction. We discuss these properties in terms of the electronic structure and the differences between the two types of clathrate.

260

Structures of type B ribose 5-phosphate isomerase from Trypanosoma cruzi shed light on the determinants of sugar specificity in the structural family  

OpenAIRE

Ribose-5-phosphate isomerase (Rpi; EC 5.3.1.6) is a key activity of the pentose phosphate pathway. Two unrelated types of sequence/structure possess this activity: type A Rpi (present in most organisms) and type B Rpi (RpiB) (in some bacteria and parasitic protozoa). In the present study, we report enzyme kinetics and crystallographic studies of the RpiB from the human pathogen, Trypanosoma cruzi. Structures of the wild-type and a Cys69Ala mutant enzyme, alone or bound to phosphate, D-ribose ...

Stern, Ana Laura; Naworyta, Agata; Cazzulo, Juan J.; Mowbray, Sherry L.

2011-01-01

261

Impact of model structure and parameterization on Penman-Monteith type evaporation models  

KAUST Repository

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.

McCabe, M.F.

2015-04-12

262

Direct metal micropatterning on needle-type structures towards bioimpedance and chemical sensing applications  

Science.gov (United States)

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 ? sensor with gas sensing capability was demonstrated by using a needle with printed Ag electrodes and Pd thin films.

Kim, Sanghyeok; Park, Jae-ho; Kang, Kyungnam; Park, Chong-Ook; Park, Inkyu

2015-01-01

263

On the flat spacetime Galileons and the Born-Infeld type structures  

CERN Document Server

We show how the flat spacetime Galileon field theories in arbitrary dimensions can be obtained through a Born-Infeld type structure. This construction involves a brane metric and non-linear combinations of derivatives of a scalar field. Our setup gives rise to some Galileon tensors and vectors useful for the variational analysis which are related to the momentum density of the probe Lovelock branes floating in a $N$-dimensional flat bulk. We find further that the Noether currents associated to these Galileon theories may be written in terms of such tensors.

Campuzano, Cuauhtemoc; Cruz, Miguel; Rojas, Efrain

2015-01-01

264

Osteogenesis imperfecta is linked to both type I collagen structural genes.  

OpenAIRE

The segregation of the two type I collagen structural gene loci COL1A1 and COL1A2 was analysed in eleven osteogenesis imperfecta pedigrees by means of restriction-site variants at, or close to, these loci. In each case, the OI gene was inherited with one or other collagen locus. As well as identifying the common OI loci the result of this analysis sets limits on the frequency of a third locus and lays the foundation for a widely available antenatal diagnostic test.

Sykes, B.; Ogilvie, D.; Wordsworth, P.; Jones, N.

1986-01-01

265

Influence of Gd addition on the magnetism and structure of Finemet-type nanocrystalline alloys  

Energy Technology Data Exchange (ETDEWEB)

The effect of rare earth addition in the structure and magnetism of melt spun nanocrystalline Finemet-type alloys devitrified from amorphous precursor ribbons is discussed. Starting with the initial composition Fe{sub 73.5}Cu{sub 1}Nb{sub 3}Si{sub 13.5}B{sub 9} an amount of 5 at% Gd is introduced into the primary alloy. The purpose is to enable after appropriate recrystallization the occurrence of hard and soft magnetic, suitably dispersed, exchange-coupled nanograins and to determine the transformation sequences of the crystallization process and the obtained crystallization products.

Crisan, O. E-mail: ocrisan@alpha2.infim.roocrisan@yahoo.com; Le Breton, J.M.; Crisan, A.D.; Machizaud, F

2004-05-01

266

A new type of antiferrodistortive structure in a double perovskite with Pb  

OpenAIRE

We have found a new structural transition in Pb2MnReO 6 at 410 K. Above this temperature, Pb2MnReO6 is cubic with disordered and dynamic atomic displacements manifested in the large thermal parameters of Pb and O atoms. Below 410 K, the antiferrodistortive shift of 2/3 of Pb2+ cations away from the high-symmetry cubic site produces a new type of monoclinic cell. The unit cell expands at the transition and the heat capacity shows a peak with thermal hysteresis. These features agree with a firs...

Blasco, Javier; Lafuerza, Sara; Garci?a, Joaqui?n; Subi?as, G.; Sa?nchez, Mari?a Concepcio?n; Cuartero, Vera; Stankiewicz, Jolanta

2011-01-01

267

Reflection-free complex absorbing potential for electronic structure calculations: Feshbach type autoionization resonance of Helium  

International Nuclear Information System (INIS)

This work represents the first successful application of reflection-free complex absorbing potential (RF-CAP) method to the study of resonances in many-electron systems. The present work introduces a systematic way for implementing RF-CAP for the electronic structure calculations using Gaussian basis sets. The method is applied to study the lowest 1S Feshbach type autoionization resonance of He. It is shown that in order to be able to introduce the RF-CAP close to the nucleus, where the electron-nucleus Coulomb attraction force is not negligible, the RF-CAP should be supplemented by a weak static field

268

Controlling Factors of Tc-Dome Structure in 1111-Type Iron Arsenide Superconductors  

OpenAIRE

We investigated the effects of phosphorus substitution on the shape of the Tc(x) dome in 1111-type SmFeAs1-yPyO1-xHx (0 H-) exerts a chemical pressure effect, i.e., a structural reduction of the Pn-Fe-Pn angle {\\alpha} (Pn = P, As) and also dopes electrons into the FePn layer to induce superconductivity. Isovalent phosphorus substitution (P3- -> As3-) can induce only a chemical pressure effect, i.e., an increase of ...

Matsuishi, Satoru; Maruyama, Takuya; Iimura, Soshi; Hosono, Hideo

2013-01-01

269

High gradient test of the C-band choke-mode type accelerating structure  

International Nuclear Information System (INIS)

The C-band (5712 MHz) choke-mode type accelerating structure will be used for SPring-8 Compact SASE-FEL Source (SCSS). To make the accelerator length short, we designed the field gradient as high as 40 MV/m. Since it is higher gradient than other traditional electron accelerators, we have to carefully check its performance (RF breakdown, dark current emission, etc.) in the high gradient test stand. The first experiment will be scheduled in this summer. In this paper, we will describe the preparation progress for the test. (author)

270

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 (60?70 %, which were effected by hydrochloric acid with concentrations of 1 M and above.

MAGDALENA TOMASEVIC-CANOVIC

2004-04-01

271

Structure and evolution of star-forming gas in late-type spiral galaxies  

CERN Document Server

We study two dimensional Fabry-Perot interferometric observations of the nearby face-on late-type spiral galaxy, NGC 628. We investigate the role of the individual HII regions together with the large-scale gravitational mechanisms which govern star formation and overall evolution in spiral galaxies. Our kinematical analysis (reinforced by literature maps in HI and CO at lower angular resolution) enables us to verify the presence of an inner rapidly rotating inner disk-like component which we attribute to long term secular evolution of the large-scale spiral arms and oval structure. We find that gas is falling in from the outer parts towards the bluer central regions. This could be an early phase in the formation of a pseudo-bulge. We find signatures of radial motions caused by an m=2 perturbation, which are likely to be responsible for the inflow of material forming the circumnuclear ring and the rapidly rotating inner structure.

Fathi, K; Zurita, A; Relano, M; Knapen, J H; Ostlin, G; Carignan, C; Chemin, L; Daigle, O; Hernández, O; Fathi, Kambiz; Beckman, John E.; Zurita, Almudena; Relano, Monica; Knapen, Johan H.; Ostlin, Goran; Carignan, Claude; Chemin, Laurent; Daigle, Olivier; Hernandez, Olivier

2007-01-01

272

Ag-2223 (Bi) tapes structure and superconducting properties in dependence of initial powder type  

International Nuclear Information System (INIS)

An investigation was carried out into the critical properties and specific features of structure in composite tapes with a core material of composition 2:2:2:3.2 in bismuth system produced by freeze drying technique and taken at different stages of the synthesis process. Consideration is given to powder behavior in the process of cold drawing and rolling of composite tapes followed by heat treatment under similar condition as well as to evolution of microstructure, specificity of texture and kinetics of superconducting phase formation. It is shown that the most favorable type of structure in heat treated superconductors develops when core material powder is used in the form of a precursor consisting of fine mixture of dioxides and ''2212'' phase resultant from calcination within the interval 750--800 C. The critical current density more than 104 A/cm2 at 77 K was achieved in the composite tapes. The results of testing for small coils are presented

273

Structures of Three Types of Local Quantum Channels Based on Quantum Correlations  

Science.gov (United States)

In a bipartite quantum system, quantum states are classified as classically correlated (CC) and quantum correlated (QC) states, the later are important resources of quantum information and computation protocols. Since correlations of quantum states may vary under a quantum channel, it is necessary to explore the influence of quantum channels on correlations of quantum states. In this paper, we discuss CC-preserving, QC-breaking and strongly CC-preserving local quantum channels of the form and obtain the structures of these three types of local quantum channels. Moreover, we obtain a necessary and sufficient condition for a quantum state to be transformed into a CC state by a specific local channel in terms of the structure of the input quantum state. Lastly, as applications of the obtained results, we present a classification of local quantum channels and describe the quantum states which are transformed as CC ones by the corresponding local quantum channel.

Guo, Zhihua; Cao, Huaixin; Qu, Shixian

2015-04-01

274

Structure of zeolite catalysis of the pentasil type, modified simultaneously by boron and phosphorus compounds  

Energy Technology Data Exchange (ETDEWEB)

Using x-ray phase analysis, IR and /sup 11/B NMR spectroscopy, the authors have studied the structure of pentasil type zeolites modified by boron and phosphorus compounds. They show that the modifier is chemically bonded to the zeolite, but does not displace the tetrahedrally coordinated atoms of the zeolite lattice. They observe BO/sub 3/ and BO/sub 4/ groups. The formation of BO/sub 4/ is explained by formation of borophosphate, and also by interaction of the B-containing component with OH groups of the zeolite. The presence of BO/sub 3/ is due to the boron anhydride impurity. They suggest the possibility of formation of polyphosphate structures also.

Kubasov, A.A.; Kitaev, L.E.; Koldasheva, E.M.; Revokatov, O.P.; Petrusevich, Yu.M.

1989-02-01

275

Labyrinth-type domain structure of heteroepitaxial SrMnO2.5 film  

Science.gov (United States)

SrMnO2.5 films grown on SrTiO3 and LSAT substrates were prepared and oxygen vacancies in the films were directly confirmed by annular bright-field imaging in a scanning transmission electron microscope. The SrMnO2.5 films show a unique maze like pattern of domains, i.e., a labyrinth-type domain structure, that arises from relaxation of strain induced by lattice mismatches. The behavior of the domain widths is explained by the geometrical relationship for estimating of the average distance of misfit dislocations. We present useful principles for controlling the domain structures with a view to potential practical applications.

Kobayashi, Shunsuke; Ikuhara, Yuichi; Yamamoto, Takahisa

2013-06-01

276

Sorbicillactone A: a structurally unprecedented bioactive novel-type alkaloid from a sponge-derived fungus.  

Science.gov (United States)

This chapter deals with the discovery of sorbicillactone A, as an illustrative example of the fruitful cooperation within BIOTECmarin--its isolation and chemical characterization, and its biological activities. Sorbicillactone A was isolated from a strain of Penicillium chrysogenum cultured from a sample of the Mediterranean sponge Ircinia fasciculata; it possesses a unique bicyclic lactone structure, seemingly derived from sorbicillin. Among the numerous known sorbicillin-derived structures, it is the first found to contain nitrogen and thus the first representative of a novel type of 'sorbicillin alkaloids', apparently originating from a likewise remarkable biosynthesis. Furthermore, the compound exhibits promising activities in several mammalian and viral test systems, in particular a highly selective cytostatic activity against murine leukemic lymphoblasts (L5178y) and the ability to protect human T cells against the cytopathic effects of HIV-1. These properties qualify sorbicillactone A or one of its derivatives for animal and (hopefully) also future therapeutic human trials. PMID:15825646

Bringmann, G; Lang, G; Mühlbacher, J; Schaumann, K; Steffens, S; Rytik, P G; Hentschel, U; Morschhäuser, J; Müller, W E G

2003-01-01

277

Structure and phase composition in type ZhS6K nickel alloy produced from granules  

International Nuclear Information System (INIS)

The effect of heating temperature, duration of heat, as well as cooling rate on the changes in the microstructure of ZhS6K type alloy, obtained from granules, is investigated. It is shown that heating temperature affects considerably the structure and phase composition of alloy, which results from coalescence and dissolution of ?'-phase dispersed particles. At 1100 deg C the formation of fine-grained (up to 1.2mm grain size) duplex microstructure with ? and ?'-phase ratio close to 1:1 takes place. It is found out that duration of heating does not considerably affect a change in the alloy phase composition although leads to some structure coarsening. Cooling rate considerably affects the size and shape of ?'-phase precipitates

278

Crystal structures of Helicobacter pylori type II dehydroquinase inhibitor complexes: new directions for inhibitor design.  

Science.gov (United States)

The crystal structures of the type II dehydroquinase (DHQase) from Helicobacter pylori in complex with three competitive inhibitors have been determined. The inhibitors are the substrate analogue 2,3-anhydroquinate (FA1), citrate, and an oxoxanthene sulfonamide derivative (AH9095). Despite the very different chemical nature of the inhibitors, in each case the primary point of interaction with the enzyme is via the residues that bind the C1 functionalities of the substrate, 3-dehydroquinate, i.e., N76, H102, I103, and H104. The DHQase/AH9095 complex crystal structure shows that sulfonamides can form a scaffold for nonsubstrate-like inhibitors and identifies a large conserved hydrophobic patch at the entrance to the active site as a locus that can be exploited in the development of new ligands. PMID:16480265

Robinson, David A; Stewart, Kirsty A; Price, Nicholas C; Chalk, Peter A; Coggins, John R; Lapthorn, Adrian J

2006-02-23

279

Electronic structure of ionic PbFCl-type compounds under pressure  

International Nuclear Information System (INIS)

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

280

Ion beam irradiation effects in strontium zirconium phosphate with NZP-structure type  

Science.gov (United States)

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 ?-decay of the incorporated actinides. In this study, ion-beam irradiation using Au- and He-ions has been used to simulate the consequences of ?-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.

Gregg, Daniel J.; Karatchevtseva, Inna; Thorogood, Gordon J.; Davis, Joel; Bell, Benjamin D. C.; Jackson, Matthew; Dayal, Pranesh; Ionescu, Mihail; Triani, Gerry; Short, Ken; Lumpkin, Gregory R.; Vance, Eric R.

2014-03-01

281

Heterotic and type II orientifold compactifications on SU(3) structure manifolds  

International Nuclear Information System (INIS)

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.)

282

Widespread distribution and structural diversity of Type IV IRESs in members of Picornaviridae.  

Science.gov (United States)

Picornavirus genomes contain internal ribosomal entry sites (IRESs) that promote end-independent translation initiation. Five structural classes of picornavirus IRES have been identified, but numerous IRESs remain unclassified. Here, previously unrecognized Type IV IRESs were identified in members of three proposed picornavirus genera (Limnipivirus, Pasivirus, Rafivirus) and four recognized genera (Kobuvirus, Megrivirus, Sapelovirus, Parechovirus). These IRESs are ~230-420 nucleotides long, reflecting heterogeneity outside a common structural core. Closer analysis yielded insights into evolutionary processes that have shaped contemporary IRESs. The presence of related IRESs in diverse genera supports the hypothesis that they are heritable genetic elements that spread by horizontal gene transfer. Recombination likely also accounts for the exchange of some peripheral subdomains, suggesting that IRES evolution involves incremental addition of elements to a pre-existing core. Nucleotide conservation is concentrated in ribosome-binding sites, and at the junction of helical domains, likely to ensure orientation of subdomains in an active conformation. PMID:25726971

Asnani, Mukta; Kumar, Parimal; Hellen, Christopher U T

2015-04-01

283

Toothpaste lava: Characteristics and origin of a lava structural type transitional between pahoehoe and aa  

Science.gov (United States)

Toothpaste lava, an important basalt structural type which illustrates the transition from pahoehoe to aa, is particularly well displayed on the 1960 Kapoho lava of Kilauea Volcano. Its transitional features stem from a viscosity higher than that of pahoehoe and a rate of flow slower than that of aa. Viscosity can be quantified by the limited settling of olivine phenocrysts and rate of flow by field observations related to the low-angle slope on which the lava flowed. Much can be learned about the viscosity, rheologic condition, and flow velocity of lavas long after solidification by analyses of their structural characteristics, and it is possible to make at least a semiquantitative assessment of the numerical values of these parameters.

Rowland, Scott K.; Walker, George P. L.

1987-08-01

284

Creep deformation and rupture behavior of type 304/308 stainless steel structural weldments  

Energy Technology Data Exchange (ETDEWEB)

The creep deformation and rupture of type 304/308 stainless steel structural weldments at 593/sup 0/C (1100/sup 0/F) 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.

McAfee, W.J.; Richardson, M.; Sartory, W.K.

1977-05-12

285

Synthetic ether type lubricants - structure and properties; Synthetische Etheroele - Struktur und Eigenschaften  

Energy Technology Data Exchange (ETDEWEB)

In almost all areas of lubrication use of synthetic lubricants increase. Polyether type oils are characterized by exceptional tribological behaviour and are used as basefluids for heavy duty and special lubricants. This paper describes chemical structures of polyalkylene glycols (PAG), polyphenyl ethers (PPE), perfluoropolyethers (PFPE), polyvinyl ethers (PVE) and reports on investigations of physical properties with respect to refrigeration compressor applications. It could be shown molecular structure greatly influences refrigerant solubility. (orig.) [German] Polyether zeichnen sich unter anderem durch ihre hervorragenden tribologischen Eigenschaften aus und werden seit Jahren als Basiskomponenten fuer Hochleistungs- und Spezialschmierstoffe verwendet. In dieser Uebersicht wird der chemische Aufbau unterschiedlicher Typen von Etheroelen beschrieben. Dazu wurden die physikalischen Eigenschaften im Hinblick auf eine moegliche Verwendung als Grundkomponenten zur Formulierung von Kaeltemaschinenoelen untersucht. Dabei hat sich gezeigt, dass die chemische Struktur grossen Einfluss auf das Loeslichkeitsverhalten mit dem Kaeltemittel R 134a besitzt. (orig.)

Fahl, J. [Fuchs DEA Schmierstoffe GmbH und Co. KG, Hamburg (Germany). Forschung und Entwicklung Kaeltemaschinenoele

2000-08-01

286

Creep deformation and rupture behavior of type 304/308 stainless steel structural weldments  

International Nuclear Information System (INIS)

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

287

Structural and magnetic Properties of TbZn-substituted calcium barium M-type nano-structured hexa-ferrites  

International Nuclear Information System (INIS)

Highlights: • Tb–Zn substituted Ca0.5Ba0.5Fe12O19 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 18–25 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 Ca0.5Ba0.5?xTbxZnyFe12?yO19, (x = 0.00–0.10; y = 0.00–1.00) ferrites prepared by sol–gel 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 (1277–2025 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

288

Wildfires alter rodent community structure across four vegetation types in southern California, USA  

Science.gov (United States)

We surveyed burned and unburned plots across four habitat reserves in San Diego County, California, USA, in 2005 and 2006, to assess the effects of the 2003 wildfires on the community structure and relative abundance of rodent species. The reserves each contained multiple vegetation types (coastal sage scrub, chaparral, woodland, and grassland) and spanned from 250 m to 1078 m in elevation. Multivariate analyses revealed a more simplified rodent community structure in all burned habitats in comparison to unburned habitats. Reduction in shrub and tree cover was highly predictive of changes in post-fire rodent community structure in the burned coastal sage scrub and chaparral habitats. Reduction in cover was not predictive for the less substantially burned woodlands and grasslands, for which we hypothesized that interspecific competition played a greater role in post-fire community structure. Across vegetation types, generalists and open habitat specialists typically increased in relative abundance, whereas closed habitat specialists decreased. We documented significant increases in relative abundance of the deer mouse (Peromyscus maniculatus Wagner) and Dulzura kangaroo rat (Dipodomys simulans Merriam). In contrast, we found significant decreases in relative abundance for the California mouse (Peromyscus californicus Gambel), San Diego pocket mouse (Chaetodipus fallax Merriam), desert woodrat (Neotoma lepida Thomas), and brush mouse (Peromyscus boylii Baird). Currently, our research program involves assessment of whether habitat conservation plans (HCPs) in southern California provide long-term protection to HCP covered species, as well as preserve ecosystem function. The scenario of increased wildfires needs to be incorporated into this assessment. We discuss our results in relation to management and conservation planning under a future scenario of larger and more frequent wildfires in southern California.

Brehme, Cheryl S.; Clark, Denise R.; Rochester, Carlton J.; Fisher, Robert N.

2011-01-01

289

The skeleton castings as a new type of cast lattice structures  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: of this paper is to present selected achievements in field of new type material - skeleton structures. Actual state of knowledge about periodic cellular materials was described. The aim of this work is to show results about mechanically optimised skeleton casting with octahedron topology. Correctness of technological parameters was investigated by microstructural research. Most important parameters of the manufacturing process were identified.Design/methodology/approach: The influence of technological parameters to the microstructure in different points of casting was described. Simulations of the mould filling processes were also carried out. Real experiments were performed to prove the simulation results. The qualitative and quantitative metallographic analysis was also carried out.Findings: It was found that the octahedron shape of internal cell causes best stress distribution and that the skeleton castings are a good alternative for cellular materials such as metal foams, lattice structures or sandwich panels.Research limitations/implications: Casting methods used to manufacture materials such as described skeleton castings confirmed their usefulness. Not well known and used yet rheological properties of liquid metals allow obtaining shape complicated structures near to metallic foams but with periodic structure.Practical implications: Technological parameters of the skeleton castings manufacturing process were developed. Without use of advanced techniques there is a possibility to manufacture relatively low cost skeleton structures in a typical foundry.Originality/value: Three dimensional cast skeleton structures with internal topology of octahedron confirmed their usefulness as elements used for energy dissipation. Obtaining the homogenous microstructure in the whole volume of complicated shape castings can be achieved.

M. Cholewa

2012-10-01

290

The solar type protostar IRAS16293-2422: new constraints on the physical structure  

CERN Document Server

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 ...

Crimier, Nicolas; Maret, Sebastien; Bottinelli, Sandrine; Caux, Emmanuel; Kahane, Claudine; Lis, Dariusz C; Olofsson, Johan

2010-01-01

291

Recent advances in the structural and molecular biology of type IV secretion systems.  

Science.gov (United States)

Bacteria use type IV secretion (T4S) systems to deliver DNA and protein substrates to a diverse range of prokaryotic and eukaryotic target cells. T4S systems have great impact on human health, as they are a major source of antibiotic resistance spread among bacteria and are central to infection processes of many pathogens. Therefore, deciphering the structure and underlying translocation mechanism of T4S systems is crucial to facilitate development of new drugs. The last five years have witnessed considerable progress in unraveling the structure of T4S system subassemblies, notably that of the T4S system core complex, a large 1 MegaDalton (MDa) structure embedded in the double membrane of Gram-negative bacteria and made of 3 of the 12 T4S system components. However, the recent determination of the structure of -3MDa assembly of 8 of these components has revolutionized our views of T4S system architecture and opened up new avenues of research, which are discussed in this review. PMID:24709394

Trokter, Martina; Felisberto-Rodrigues, Catarina; Christie, Peter J; Waksman, Gabriel

2014-08-01

292

Structural and functional cardiac changes in myotonic dystrophy type 1: a cardiovascular magnetic resonance study  

Directory of Open Access Journals (Sweden)

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.

Hermans Mieke CE

2012-07-01

293

Investigations of structure and dynamics of water solvation of the type I antifreeze protein  

Science.gov (United States)

We use molecular dynamics simulations to study the water structure and dynamics around the winter flounder antifreeze protein (AFP) and its two mutant forms in which the four key threonine residues of the winter flounder AFP are mutated to alanines and serines, respectively. The TIP4P-Ew water model is used to better describe the water interactions and water structure; all simulations are performed at 245.5 K, a temperature near the freezing point of the TIP4P-Ew water model. Analysis of structural and dynamic properties of the water around the threonines in the winter flounder AFP reveals that the water structure is ordered around the threonine residues, especially in the second-solvation shell. Alanine and serine mutations instead promote water hydration in the first-solvation shell. Also our calculations show that in the close vicinity of the threonine residues of the wild-type AFP, the mobility of water molecules is substantially decreased. A smaller effect is observed for the weakly active alanine-substituted mutant, and no effect is observed for the inactive serine-substituted mutant. The results of this study suggest that water ordering and immobilization play important roles in the recognition and adsorption of the antifreeze protein to ice.

Cui, Jun; Battle, Keith; Wierzbicki, Andrzej; Madura, Jeffry D.

294

Structural, infrared, magnetic and microwave absorption properties of rare earth doped X-type hexagonal nanoferrites  

International Nuclear Information System (INIS)

Highlights: •A series of X-type hexagonal ferrites were prepared by sol–gel method. •The XRD analysis showed that the X-type hexagonal structure. •The c/a ratio of these samples falls in the range of X-type hexagonal ferrites. •The magnetic properties enhances with the increase of Nd–Co contents. •The samples show the reflection loss at smaller frequencies. -- Abstract: A series of Sr2?xNdxNi2 Fe28?yCoyO46 (x = 0.02, 0.04, 0.06, 0.08, 0.10 and y = 0.1, 0.2, 0.3, 0.4, 0.5) X-type hexagonal ferrites has been prepared by sol–gel method at 1250 °C for 6 h. XRD analysis shows the single phase of the prepared ferrites material. The lattice constant values and c/a ratio shows that the present assembled material belongs to the family X-type hexagonal ferrites. The peaks in the FTIR spectra are the characteristics of the hexagonal ferrites. The crystallite size measured by Scherer formula is in good agreement with the crystallite size measured by TEM and HRTEM. The enhancement in the magnetic properties can easily be observed with the doping of rare earth element Nd3+ and divalent Co2+. Due to high saturation and low coercivity values the present material can be good microwave absorber. The temperature dependent saturation and remanance magnetization decreases monotonically with temperature. The minimum value of reflection loss enhances with the substituent and the attenuation constant results are in agreement with reflection loss results

295

Structural comparison between type I and type II antagonists: possible implications in the drug design of AT1 antagonists.  

Science.gov (United States)

Analogues of sarilesin (type I AT1 antagonists), and sarmesin (type II AT1 antagonists) with homoserine (hSer) at position 8 were prepared and bioassayed. The presence of a Tyr4-Ile5-His6 bend found in sarmesin but not in sarilesin was identified. The obtained results coupled with conformational analysis studies, using a combination of NMR spectroscopy and computational chemistry, propose important conformational and stereoelectronic properties for agonist and antagonist activity at AT1 receptors. PMID:10782679

Roumelioti, P; Tselios, T; Alexopoulos, K; Mavromoustakos, T; Kolocouris, A; Moore, G J; Matsoukas, J M

2000-04-17

296

Nuclear Structure and the Fate of Core Collapse (Type II) Supernova  

CERN Document Server

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...

Gai, Moshe

2014-01-01

297

Ca8In3, a structure related to the BiF3 type  

International Nuclear Information System (INIS)

Mr=665.1, triclinic, aP22, P1, a=9.606(2), b=9.717(2), c=9.782(2) A, ?=69.65(2), ?=78.85(2), ?=60.34(1)0, V=743.7(3) A3, Z=2, Dx=2.97 Mg m-3, MoK?, ?=0.7107 A, ?=7.13 mm-1, F(000)=614, room temperature, R=0.027 for 2789 reflections with F0>3?(F0). The Ca8In3 structure is derived by distortion of the face-centered cubic BiF3 type (also called AlFe3 or BiLi3 type). It can be described as a three-layered structure along the a axis, the atoms being located at x?0, x?1/3 and x?2/3. Three different coordination polyhedra are found around the In atoms: distorted cubicosahedra (ten-vertex polyhedra) for In(1), In(2), In(4) and In(6), cubes for In(3) and icosahedra for In(5). Distorted cubicosahedra centered by In at x?0 and x?1/3 are alternately joined by an edge and by a face and form parallel rows; cubes and icosahedra centered by In at x?2/3 are joined by an edge and also form parallel rows. (orig.)

298

Synthesis and structural characterization of pincer type bicyclic diacyloxy- and diazaselenuranes.  

Science.gov (United States)

Synthesis and structural characterization of a new class of pincer type bicyclic diacyloxy- and diazaselenuranes is reported. The reaction of dimethyl 2-bromo-5-tert-butylisophthalate (28) with sodium benzeneselenolate affords the corresponding monoselenide, dimethyl 5-tert-butyl-2-(phenylselanyl)isophthalate (29). Reduction of 29 with LiAlH(4) provides 5-tert-butyl-2-(phenylselanyl)-1,3-phenylene)dimethanol 31. Oxidation of 29 or its hydrolyzed derivative, 5-tert-butyl-2-(phenylselanyl)isophthalic acid (30), with H(2)O(2) results in the formation of bicyclic diacyloxyselenurane (25). The reaction of 30 with aniline using the DCC coupling reaction gives 5-tert-butyl-N(1),N(3)-diphenyl-2-(phenylselanyl)isophthalamide (38). Reaction of 38 with H(2)O(2) leads to the formation of the corresponding bicyclic diazaselenurane (27) via selenoxide intermediate 39. Compounds 25, 27, 29 and 31 were characterized by single crystal X-ray crystallography. The structural aspects of the pincer type bicyclic chalcogenuranes are investigated using experimental and computational studies and compared with the related systems. PMID:21850325

Selvakumar, K; Singh, Harkesh B; Goel, Nidhi; Singh, Udai P; Butcher, Ray J

2011-10-14

299

Synthesis and ferroelectric properties of rare earth compounds with tungsten bronze-type structure  

Energy Technology Data Exchange (ETDEWEB)

Highlights: {center_dot} Polycrystalline materials with the tungsten bronze-type structure have been synthesized and characterized. {center_dot} Effect of the incorporation of rare earth ions and paramagnetic cations (Fe{sup 3+}) into a matrix ferroelectrically active was studied. {center_dot} Ferroelectric transition is pronounced by a large thermal hysteresis during the heating and cooling cycles. {center_dot} Phase transitions around T{sub c} were confirmed by differential scanning calorimetry (DSC) measurements. - Abstract: Polycrystalline materials with a general formula Pb{sub 2}Na{sub 0.8}R{sub 0.2}Nb{sub 4.8}Fe{sub 0.2}O{sub 15} (R = Dy, Eu, Sm, Nd, La) have been synthesized, in air by a high temperature solid state reaction method. X-ray diffraction study, at room temperature, revealed that they crystallize in the tungsten bronze-type structure. Dielectric properties were performed, in the temperature range 25-500 deg. C, at three different frequencies 10, 100 and 1000 kHz. The ferroelectric transition is pronounced by a large thermal hysteresis during the heating and cooling cycles. The determined Curie temperature values T{sub c} were discussed as a function of rare earth size. Phase transitions around T{sub c} for the investigated compounds were confirmed by differential scanning calorimetry (DSC) measurements.

Bouziane, M., E-mail: bouzianemeryem@yahoo.fr [Laboratoire de Chimie du Solide Appliquee, Faculte des Sciences, Avenue Ibn Batouta, BP 1014, Rabat (Morocco); Taibi, M. [Laboratoire de Physico-Chimie des Materiaux, LAF 502, Ecole Normale Superieure, BP 5118, Rabat (Morocco); Boukhari, A. [Laboratoire de Chimie du Solide Appliquee, Faculte des Sciences, Avenue Ibn Batouta, BP 1014, Rabat (Morocco)

2011-10-03

300

Generalized N=1 and N=2 structures in M-theory and type II orientifolds  

CERN Document Server

We consider M-theory and type IIA reductions to four dimensions with N=2 and N=1 supersymmetry and discuss their interconnection. Our work is based on the framework of Exceptional Generalized Geometry (EGG), which extends the tangent bundle to include all symmetries in M-theory and type II string theory, covariantizing the local U-duality group E7. We describe general N=1 and N=2 reductions in terms of SU(7) and SU(6) structures on this bundle and thereby derive the effective four-dimensional N=1 and N=2 couplings, in particular we compute the Kahler and hyper-Kahler potentials as well as the triplet of Killing prepotentials (or the superpotential in the N=1 case). These structures and couplings can be described in terms of forms on an eight-dimensional tangent space where SL(8) contained in E7 acts, which might indicate a description in terms of an eight-dimensional internal space, similar to F-theory. We finally discuss an orbifold action in M-theory and its reduction to O6 orientifolds, and show how the pr...

Graña, Mariana

2012-01-01

301

Can a half-metallic zincblende-type structure be stabilized via epitaxy?  

CERN Document Server

The need for spin-injectors having the same zincblende-type crystal structure as conventional semiconductor substrates has created significant interests in theoretical predictions of possible metastable ``half-metallic'' zincblende ferromagnets, which are normally more stable in other structure-types, e.g., NiAs. Such predictions were based in the past on differences $\\Delta_{\\rm bulk}$ in the total-energies of the respective {\\em bulk} crystal forms (zincblende and NiAs). We show here that the appropriate criterion is comparing difference $\\Delta_{\\rm epi}(a_s)$ in {\\em epitaxial} total-energies. This reveals that even if $\\Delta_{\\rm bulk}$ is small, still for MnAs, CrSb, CrAs, CrTe, $\\Delta_{\\rm epi}(a_s) > 0$ for all substrate lattice constant $a_s$, so the zincblende phase is not stabilized. For CrS we find $\\Delta_{\\rm epi}(a_s) 6.2$ \\AA\\ and half-metallic.

Zhao, Y J; Zhao, Yu-Jun; Zunger, Alex

2004-01-01

302

Growth of rectangular hollow tube crystals with rutile-type structure in supercritical fluids  

Science.gov (United States)

Super critical fluids are well known as suitable solvents for dissolution and extraction processes, because it exhibits extreme high solubility and reactivity. However further experimental development using supercritical fluid would offer new insight in material science, especially the synthesis and crystal growth of novel materials. We report the successful growth of single crystals with the rutile-type structure (TiO2, Co-doped TiO2, SiO2, GeO2 and SnO2) in supercritical fluids (water or oxygen) using a laser heated diamond-anvil cell up to a pressure of 7 GPa. The resultant product showed the rectangular hollow tube morphology, a several tens of microns in length and a wall thickness of less than 500 nm. TEM analyses demonstrated that this rectangular hollow tube single crystals were surrounded by the {110} faces and grown along the [001] direction. The preferential growth of {110} faces is consistent with the lowest surface energy of {110} faces of the rutile-type structure. In addition, the rapid cooling rate in LHDAC and high solubility of supercritical fluids also play an important role for the formation of the rectangular hollow tube. The details of the synthesis procedure, characterization and growth mechanism are discussed in this paper.

Niwa, K.; Ikegaya, H.; Taguchi, T.; Muto, S.; Tokunaga, T.; Hasegawa, M.

2014-05-01

303

Structural Analysis of the Binding of Type I, I1/2, and II Inhibitors to Eph Tyrosine Kinases.  

Science.gov (United States)

We have solved the crystal structures of the EphA3 tyrosine kinase in complex with nine small-molecule inhibitors, which represent five different chemotypes and three main binding modes, i.e., types I and I1/2 (DFG in) and type II (DFG out). The three structures with type I1/2 inhibitors show that the higher affinity with respect to type I is due to an additional polar group (hydroxyl or pyrazole ring of indazole) which is fully buried and is involved in the same hydrogen bonds as the (urea or amide) linker of the type II inhibitors. Overall, the type I and type II binding modes belong to the lock-and-key and induced fit mechanism, respectively. In the type II binding, the scaffold in contact with the hinge region influences the position of the Phe765 side chain of the DFG motif and the orientation of the Gly-rich loop. The binding mode of Birb796 in the EphA3 kinase does not involve any hydrogen bond with the hinge region, which is different from the Birb796/p38 MAP kinase complex. Our structural analysis emphasizes the importance of accounting for structural plasticity of the ATP binding site in the design of type II inhibitors of tyrosine kinases. PMID:25589935

Dong, Jing; Zhao, Hongtao; Zhou, Ting; Spiliotopoulos, Dimitrios; Rajendran, Chitra; Li, Xiao-Dan; Huang, Danzhi; Caflisch, Amedeo

2015-01-01

304

A method for evaluating structural transducers used in Type B package testing  

Science.gov (United States)

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.

Madsen, Marcella M.; Uncapher, William L.; Bronowski, David R.; Stenberg, Duane R.

1989-01-01

305

A method for evaluating structural transducers used in Type B package testing  

International Nuclear Information System (INIS)

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. 3 refs., 10 figs., 1 tab

306

Structural investigations on ?-hase type nitrides M3N1+x (M Mn, Fe, Ni)  

International Nuclear Information System (INIS)

Complete text of publication follows. ?-phase type interstitial compounds have an hcp arrangement of metal atoms with interstitial atoms occupying less then 1/2 of the octahedral interstices. Characteristic for the ?-type ordering of the interstitials is a 31/2 x 31/2 x 1 superstructure relative to hcp. However, the distribution of N is a multiparameter problems leading to ?-type phase subtypes of different symmetry (P6322, P3-bar1m, P312). An appropriate description of ordering is possible by applying static concentration waves (1). Some ?-nitrides of Mn, Fe and Ni (M3N1+x) were investigated using neutron powder diffraction. For the order-disorder transitions primary and secondary order-parameters were identified. In some cases homometric structures occur what is due to a loss of information from the diffraction patterns. As a function of the metal atom we found an increasing tendency of ordering in the series Mn, Fe and Ni. This can be discussed in terms of N-N-distances but also electronic effects. (author)

307

Types of structural chromosome aberrations and their incidences in human spermatozoa X-irradiated in vitro  

International Nuclear Information System (INIS)

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 ?-rays. The repair mechanism of X-ray-induced sperm DNA lesions is also discussed. (author). 21 refs.; 4 figs.; 4 tabs

308

Recent Structural Evolution of Early-Type Galaxies: Size Growth from z=1 to z=0  

CERN Document Server

Strong size and internal density evolution of early-type galaxies between z~2 and the present has been reported by several authors. Here we analyze samples of nearby and distant (z~1) galaxies with dynamically measured masses in order to confirm the previous, model-dependent results and constrain the uncertainties that may play a role. Velocity dispersion measurements are taken from the literature for 50 morphologically selected 0.8type galaxies with typical masses 2e11 Msol. Sizes are determined with ACS imaging. We compare the distant sample with a large sample of nearby (0.04type galaxies extracted from the SDSSfor which we determine sizes, masses, and densities in a consistent manner, using simulations to quantify systematic differences between the size measurements of nearby and distant galaxies. We find a highly significant structural difference between the nearby and distant samples, regardless of sample selection effects. The implied evolution ...

van der Wel, Arjen; Zirm, Andrew W; Franx, Marijn; Rettura, Alessandro; Illingworth, Garth D; Ford, Holland C

2008-01-01

309

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

DEFF Research Database (Denmark)

O-GalNAc-glycosylation is one of the main types of glycosylation in mammalian cells. No consensus recognition sequence for the O-glycosyltransferases is known, making prediction methods necessary to bridge the gap between the large number of known protein sequences and the small number of proteins experimentally investigated with regard to glycosylation status. From O-GLYCBASE a total of 86 mammalian proteins experimentally investigated for in vivo O-GalNAc sites were extracted. Mammalian protein homolog comparisons showed that a glycosylated serine or threonine is less likely to be precisely conserved 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 approach. The best overall network used as input amino acid composition, averaged surface accessibility predictionstogether with substitution matrix profile encoding of the sequence. To improve prediction on isolated (single) sites, networks were trained on isolated sites only. The final method combines predictions from the best overall network and the best isolated site network; this prediction method correctly predicted 76% of the glycosylated residues and 93% of the nonglycosylated residues. NetOGlyc 3.1 can predict sites for completely new proteins without losing its performance. The fact that the sites 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.

Julenius, Karin; MØlgaard, Anne

2005-01-01

310

Crystal structure of a monomeric thiolase-like protein type 1 (TLP1) from Mycobacterium smegmatis.  

Science.gov (United States)

An analysis of the Mycobacterium smegmatis genome suggests that it codes for several thiolases and thiolase-like proteins. Thiolases are an important family of enzymes that are involved in fatty acid metabolism. They occur as either dimers or tetramers. Thiolases catalyze the Claisen condensation of two acetyl-Coenzyme A molecules in the synthetic direction and the thiolytic cleavage of 3-ketoacyl-Coenzyme A molecules in the degradative direction. Some of the M. smegmatis genes have been annotated as thiolases of the poorly characterized SCP2-thiolase subfamily. The mammalian SCP2-thiolase consists of an N-terminal thiolase domain followed by an additional C-terminal domain called sterol carrier protein-2 or SCP2. The M. smegmatis protein selected in the present study, referred to here as the thiolase-like protein type 1 (MsTLP1), has been biochemically and structurally characterized. Unlike classical thiolases, MsTLP1 is a monomer in solution. Its structure has been determined at 2.7 Å resolution by the single wavelength anomalous dispersion method. The structure of the protomer confirms that the N-terminal domain has the thiolase fold. An extra C-terminal domain is indeed observed. Interestingly, it consists of six ?-strands forming an anti-parallel ?-barrel which is completely different from the expected SCP2-fold. Detailed sequence and structural comparisons with thiolases show that the residues known to be essential for catalysis are not conserved in MsTLP1. Consistent with this observation, activity measurements show that MsTLP1 does not catalyze the thiolase reaction. This is the first structural report of a monomeric thiolase-like protein from any organism. These studies show that MsTLP1 belongs to a new group of thiolase related proteins of unknown function. PMID:22844533

Janardan, Neelanjana; Harijan, Rajesh K; Wierenga, Rikkert K; Murthy, Mathur R N

2012-01-01

311

Complex regional pain syndrome type I affects brain structure in prefrontal and motor cortex.  

Science.gov (United States)

The complex regional pain syndrome (CRPS) is a rare but debilitating pain disorder that mostly occurs after injuries to the upper limb. A number of studies indicated altered brain function in CRPS, whereas possible influences on brain structure remain poorly investigated. We acquired structural magnetic resonance imaging data from CRPS type I patients and applied voxel-by-voxel statistics to compare white and gray matter brain segments of CRPS patients with matched controls. Patients and controls were statistically compared in two different ways: First, we applied a 2-sample ttest to compare whole brain white and gray matter structure between patients and controls. Second, we aimed to assess structural alterations specifically of the primary somatosensory (S1) and motor cortex (M1) contralateral to the CRPS affected side. To this end, MRI scans of patients with left-sided CRPS (and matched controls) were horizontally flipped before preprocessing and region-of-interest-based group comparison. The unpaired ttest of the "non-flipped" data revealed that CRPS patients presented increased gray matter density in the dorsomedial prefrontal cortex. The same test applied to the "flipped" data showed further increases in gray matter density, not in the S1, but in the M1 contralateral to the CRPS-affected limb which were inversely related to decreased white matter density of the internal capsule within the ipsilateral brain hemisphere. The gray-white matter interaction between motor cortex and internal capsule suggests compensatory mechanisms within the central motor system possibly due to motor dysfunction. Altered gray matter structure in dorsomedial prefrontal cortex may occur in response to emotional processes such as pain-related suffering or elevated analgesic top-down control. PMID:24416397

Pleger, Burkhard; Draganski, Bogdan; Schwenkreis, Peter; Lenz, Melanie; Nicolas, Volkmar; Maier, Christoph; Tegenthoff, Martin

2014-01-01

312

Structural and dynamic properties that govern the stability of an engineered fibronectin type III domain.  

Science.gov (United States)

Consensus protein design is a rapid and reliable technique for the improvement of protein stability, which relies on the use of homologous protein sequences. To enhance the stability of a fibronectin type III (FN3) domain, consensus design was employed using an alignment of 2123 sequences. The resulting FN3 domain, FN3con, has unprecedented stability, with a melting temperature >100°C, a ?GD-N of 15.5 kcal mol(-1) and a greatly reduced unfolding rate compared with wild-type. To determine the underlying molecular basis for stability, an X-ray crystal structure of FN3con was determined to 2.0 Å and compared with other FN3 domains of varying stabilities. The structure of FN3con reveals significantly increased salt bridge interactions that are cooperatively networked, and a highly optimized hydrophobic core. Molecular dynamics simulations of FN3con and comparison structures show the cooperative power of electrostatic and hydrophobic networks in improving FN3con stability. Taken together, our data reveal that FN3con stability does not result from a single mechanism, but rather the combination of several features and the removal of non-conserved, unfavorable interactions. The large number of sequences employed in this study has most likely enhanced the robustness of the consensus design, which is now possible due to the increased sequence availability in the post-genomic era. These studies increase our knowledge of the molecular mechanisms that govern stability and demonstrate the rising potential for enhancing stability via the consensus method. PMID:25691761

Porebski, Benjamin T; Nickson, Adrian A; Hoke, David E; Hunter, Morag R; Zhu, Liguang; McGowan, Sheena; Webb, Geoffrey I; Buckle, Ashley M

2015-03-01

313

Preparation, structure and electrical conductivity of pyrochlore-type samarium-lanthanum zirconate ceramics  

International Nuclear Information System (INIS)

Highlights: ? Dense Sm2-xLaxZr2O7 ceramics were prepared by pressureless-sintering at 1973 K. ? Sm2-xLaxZr2O7 ceramics have a single phase of pyrochlore-type structure. ? The electrical conductivity of Sm2-xLaxZr2O7 increases with increasing temperature. ? Sm2-xLaxZr2O7 ceramics are oxide-ion conductors in low oxygen partial pressure. ? The electrical conductivity of Sm2-xLaxZr2O7 decreases with increasing La content. -- Abstract: A series of zirconate compounds with the general formula Sm2-xLaxZr2O7 (0 ? x ? 1.0) were prepared by pressureless-sintering method at 1973 K for 10 h in air. The relative density, structure and electrical conductivity of Sm2-xLaxZr2O7 ceramics were investigated by the Archimedes method, X-ray diffraction and impedance spectroscopy measurements. Sm2-xLaxZr2O7 (0 ? x ? 1.0) ceramics exhibit a pyrochlore-type structure. The measured electrical conductivity of Sm2-xLaxZr2O7 ceramics obeys the Arrhenius relation and gradually increases with increasing temperature from 673 to 1173 K. Sm2-xLaxZr2O7 ceramics are oxide-ion conductors in the oxygen partial pressure range of 1.0 x 10-4 to 1.0 atm at all test temperature levels. The electrical conductivity of Sm2-xLaxZr2O7 ceramics decreases with increasing lanthanum content at identical temperature levels.

314

Crystal structure of a type-II cohesin module from the Bacteroides cellulosolvens cellulosome reveals novel and distinctive secondary structural elements.  

Science.gov (United States)

The incorporation of enzymes into the multi-enzyme cellulosome complex and its anchoring to the bacterial cell surface are dictated by a set of binding interactions between two complementary protein modules: the cohesin and the dockerin. In this work, the X-ray crystal structure of a type-II cohesin from scaffoldin A of Bacteroides cellulosolvens has been determined to a resolution of 1.6 angstroms using molecular replacement. The type-II B. cellulosolvens cohesin (Bc-cohesin-II) is the first detailed description of a crystal structure for a type-II cohesin, and its features were compared with the known type-I cohesins from Clostridium thermocellum and Clostridium cellulolyticum (Ct-cohesin-I and Cc-cohesin-I, respectively). The overall jelly-roll topology of the type-II Bc-cohesin is very similar to that observed for the type-I cohesins with three additional secondary structures: an alpha-helix and two "beta-flaps" that disrupt the normal course of a beta-strand. In addition, beta-strand 5 is elevated by approximately 4 angstroms on the surface of the molecule, relative to the type-I Ct and Cc-cohesins. Like its type-I analogue, the hydrophobic/aromatic core of Bc-cohesin-II comprises an upper and lower core, but an additional aromatic patch and conserved tryptophan at the crown of the molecule serves to stabilize the alpha-helix of the type-II cohesin. Comparison of Bc-cohesin-II with the known type-I cohesin-dockerin heterodimer suggests that each of the additional secondary structural elements assumes a flanking position relative to the putative dockerin-binding surface. The raised ridge formed by beta-strand 5 confers additional distinctive topographic features to the proposed binding interface that collectively distinguish between the type-II and type-I cohesins. PMID:15808849

Noach, Ilit; Frolow, Felix; Jakoby, Hilla; Rosenheck, Sonia; Shimon, Lindaj W; Lamed, Raphael; Bayer, Edward A

2005-04-22

315

Community Structure of Skipper Butterflies (Lepidoptera, Hesperiidae) along Elevational Gradients in Brazilian Atlantic Forest Reflects Vegetation Type Rather than Altitude  

OpenAIRE

Species turnover across elevational gradients has matured into an important paradigm of community ecology. Here, we tested whether ecological and phylogenetic structure of skipper butterfly assemblages is more strongly structured according to altitude or vegetation type along three elevation gradients of moderate extent in Serra do Mar, Southern Brazil. Skippers were surveyed along three different mountain transects, and data on altitude and vegetation type of every collection site were recor...

Carneiro, Eduardo; Mielke, Olaf Hermann Hendrik; Casagrande, Mirna Martins; Fiedler, Konrad

2014-01-01

316

STRUCTURAL PERFORMANCE OF TWO TYPES OF WALL SLAB CONNECTION UNDER OUT-OF-PLANE LATERAL CYCLIC LOADING  

OpenAIRE

Currently, most of the high-rise buildings in Malaysia are constructed using tunnel form system. However, this type of structural system is still questionable of its safety under ground motion. Thus, the main objective of this study is to test and compare the structural performance of two types of wall-slab connection namely cross and anchorage bracings under reversible quasi-static cyclic loading. Two identical sub-assemblage of wall-slab connections are designed, constructed and tested in h...

AHMED ABDULRAZZAQ NASSER AL-AGHBARI; SITI HAWA HAMZAH; NOR HAYATI ABDUL HAMID; NURHANIZA ABDUL RAHMAN

2012-01-01

317

Inelastic response of PCRV structure model with star-type support under horizontal loads  

International Nuclear Information System (INIS)

The report presents the test results of scaled models for prestressed concrete reactor vessel (PCRV) structure with star-shaped support under horizontal loads. A scale factor of 1/70 to a proto-type PCRV structure for large HTGR is used for both static and dynamic loading test models, while a 1/15 scaled model is used for static loading tests. The static behaviors such as a load-deflection envelope of the 1/70 model are predicted well by an inelastic analysis in consideration with appearance of concrete cracks and reinforcing bar yielding. It is also ascertained by the test results of the 1/15 model under static alternative loads that the same analysis procedure can be applicable to the evaluation of the elastic and inelastic behaviors of PCRV structure with support. Based on the static loading test results of both scaled models, a tri-linearized load-deflection envelope and an equivalent linearized mathematical model for hysteresis loop are assumed in a dynamic analysis. A dynamic response analysis of the 1/70 model subjected to earthquake-like base motion is conducted by the similar manner above-mentioned and the calculated results show a good correlation with the test results

318

Oxidative dehydrogenation of isobutyl alcohol over different structure type of zeolites  

International Nuclear Information System (INIS)

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 conlyst leaded considerable increasing of conversion of alcohol and selectivity of the process and stability of operation of catalysts

319

Optimization of chemical structure of Schottky-type selection diode for crossbar resistive memory.  

Science.gov (United States)

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

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

320

Structural and electrical properties of p-type ZnO films prepared by Ultrasonic Spray Pyrolysis  

International Nuclear Information System (INIS)

Effects of atomic ratio of Zn:N:Al and solution concentration on the structural and electrical characteristic of ZnO films deposited by Ultrasonic Spray Pyrolysis using N-Al co-doping technique were investigated. Hall measurement indicated that with increasing Al doping, conductive type of ZnO thin films changed from n-type to p-type and then to n-type again. However, the solution concentration almost has no effect on the structural and electrical properties of p-type ZnO films. X-ray Photoelectron Spectroscopy indicated that the presence of Al indeed facilitates the incorporation of N through the formation of N-Al bonds in co-doped ZnO films. In addition, Photoluminescence spectra showed p-type ZnO films with a low density of native defects

321

Structural-electrical-optical properties relationship of sodium superionic conductor sputter-deposited coatings  

International Nuclear Information System (INIS)

Thin films of various compositions in the Na2O-SiO2-P2O5-ZrO2 system were deposited in glassy form by reactive magnetron sputtering. An analysis by spectrophotometry showed an increase of the extinction coefficient (k) with the amount of Fe contamination. This contamination, originating from parasitic plasmas, was suppressed when convenient protections were used. Therefore, it was possible to produce optical clear films. A structural study by X-ray diffraction and Raman spectroscopy proved a reorganization in the amorphous state at low temperature and the appearance of a NASICON structure around 750 deg. C. The ionic conductivity, measured by impedance spectroscopy, and the optical properties were strongly affected by the thermal annealing process. The reorganization in the amorphous state and strong modifications of the ionic conductivity values and the refractive index (n) appeared in the same range of temperatures. This suggested a strong correlation between these different phenomena

322

Development of Materials and Structures for p-type Contacts in Cadmium Telluride Solar Cells  

Science.gov (United States)

Solar cells based on CdTe absorbers are attractive due to the optimal direct band gap energy and large absorption coefficient of CdTe, however, their performance and commercialization is hindered by the lack of reliable p-type contacts. CdTe has a low carrier concentration and a large electron affinity, which results in a requirement of non-realistic work functions for metals to be used as back contacts in the solar cell. Even noble metals such as Ag present a significantly large potential barrier for holes, thereby reducing the hole current through the semiconductor/metal interface. Several attempts to resolve this challenge have been tried, however, many drawbacks have been encountered. Two particular systems, namely Cu2Te thin films and CdTe/ZnTe strained-layer superlattices, are investigated for their potential use as ohmic contacts in CdTe solar cells. A detailed analysis of the optical, electrical, and structural properties of Cu2Te thin films deposited by magnetron sputtering is presented. It is shown that these films have an indirect band gap and highly degenerate semiconductor behavior. The large p-type carrier concentration of Cu2Te films is highly desirable for the application of Cu2Te as a p-type contact to CdTe. In-depth studies of optical transitions and miniband transport in strained-layer CdTe/ZnTe superlattices are presented as well. The band offsets between CdTe and ZnTe were determined by comparison of measured and calculated optical transitions. Superlattice structures that offer best contact performance have been identified by use of tunneling probability simulations. Characterization of CdTe solar cells with above mentioned contacts indicated that contacts based on CdTe/ZnTe superlattices are a viable Cu free option for stable and reliable p-type contacts in CdTe solar cell. The contact performance of Cu2Te thin films was comparable to that of CdTe/ZnTe superlattices and both demonstrated an advantage over contacts based on ZnTe:N thin films which were used a standard.

Ferizovic, Dino

323

The influence of dendritic structure stereology on frictional wear of cast steel Cr-Mo-V-Ni-Cu type  

International Nuclear Information System (INIS)

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)

324

Monoclinic Sr2Mg3H10 with Ba2Ni3F10-type structure  

International Nuclear Information System (INIS)

Sr2Mg3H10 and its deuteride were prepared from SrMg2 alloy at 700 K under 75 bar hydrogen (65 bar deuterium) pressure and characterized by X-ray and neutron powder diffraction. They crystallize with the monoclinic Ba2Ni3F10 structure type in space group C2/m (No. 12), with the following cell parameters at 295 K; a=17.586(5) A, b=5.742(2) A, c=7.491(2) A, ?=111.51(2) , V=703.8(2) A3 (hydride); a=17.539(4) A, b=5.730(1) A, c=7.480(2) A, ?=111.48(2) , V=699.5(2) A3 (deuteride); Z=4. The metal-deuterium bond distances range from 1.81 to 2.14 A (Mg-D) and from 2.49 to 2.96 A (Sr-D). (orig.)

325

Thermodynamical stability and electronic structure of a perovskite-type hydride, NaMgH3  

International Nuclear Information System (INIS)

Thermodynamical stability and electronic structure of a perovskite-type hydride, NaMgH3, exhibiting reversible decomposition and recombination reactions, were studied experimentally. NaMgH3 decomposes in two steps accompanying hydrogen desorption reactions, and the enthalpy change (?H) and the entropy change (?S) are calculated to be ?H(1) = -93.9(6) kJ/mol H2 and ?S(1) = -116.2(9) J/K mol H2 for the first step, and ?H(2) = -102.2(4) kJ/mol H2 and ?S(2) = -125.9(6) J/K mol H2 for the second step, respectively. Maximum entropy method (MEM)/Rietveld analysis of synchrotron X-ray diffraction profiles indicated that NaMgH3 contains two hydrogen anions at the different occupation sites

326

Linear algebraic analyses of structures with one predominant type of anomalous scatterer  

International Nuclear Information System (INIS)

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.)

327

New cadmium and rare-earth metal molybdates with scheelite-type structure  

International Nuclear Information System (INIS)

New cadmium and rare-earth metal molybdates with the formula Cd0.25RE0.50MoO4 (RE = Pr, Nd, Sm-Dy) were synthesized by the solid-state reaction of CdMoO4 with corresponding RE2(MoO4)3. The obtained compounds crystallize in the scheelite-type structure. They were characterized here by XRD, DTA-TG, IR and EPR methods. The Cd0.25RE0.50MoO4 compounds showed solubility in CdMoO4 forming the CdxRE2-2x(MoO4)3-2x (0.50 3+ ions content, that Gd3+ ions can be located at sites of octahedral symmetry, and both temperature and gadolinium content have an influence on local magnetic interaction and relaxation processes of Gd3+ ions.

328

Singularity Structures in Coulomb-Type Potentials in Two Body Dirac Equations of Constraint Dynamics  

CERN Document Server

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 lead 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 th...

Crater, Horace W; Wong, Cheuk-Yin

2008-01-01

329

Cascade-driven migration of structural interfaces: A new type of irradiation-induced phase transformation  

Science.gov (United States)

In Ti-Cr alloys containing both the Laves phase (ordered TiCr2) and the ? phase (bcc solid solution), 1 MeV Kr+ irradiation at temperatures <250 K amorphizes the Laves phase but not the ? phase. The irradiation-induced amorphous material transforms into polycrystalline ? upon warming to room temperature. In contrast, irradiation at room temperature causes the ? phase to grow by migration of the ?/Laves interface; no change in local composition across the migrating interface is observed. The ? phase also grows during prolonged irradiation at 100 K, but the velocity of the ?/amorphous interface per unit calculated atomic displacement rate is more than three orders of magnitude lower than that of the ?/Laves interface at room temperature. An interpretation of this new type of irradiation-induced phase transformation is presented in terms of displacement cascade formation and dynamic recovery at the structural interface that exists between the two phases.

Allen, C. W.; Rehn, L. E.; Wiedersich, H.

1987-06-01

330

Topology of large-scale structure by galaxy type hydrodynamic simulations  

CERN Document Server

The topology of large scale structure is studied as a function of galaxy type using the genus statistic. In hydrodynamical cosmological CDM simulations, galaxies form on caustic surfaces (Zeldovich pancakes) then slowly drain onto filaments and clusters. The earliest forming galaxies in the simulations (defined as ``ellipticals") are thus seen at the present epoch preferentially in clusters (tending toward a meatball topology), while the latest forming galaxies (defined as ``spirals") are seen currently in a spongelike topology. The topology is measured by the genus (= number of ``donut" holes - number of isolated regions) of the smoothed density-contour surfaces. The measured genus curve for all galaxies as a function of density obeys approximately the theoretical curve expected for random-phase initial conditions, but the early forming elliptical galaxies show a shift toward a meatball topology relative to the late forming spirals. Simulations using standard biasing schemes fail to show such an effect. Larg...

Gott, J R; Ostriker, J P; Gott, J Richard; Cen, Renyue; Ostriker, Jeremiah P

1995-01-01

331

Quasiparticle band structures and thermoelectric transport properties of p-type SnSe  

Science.gov (United States)

We used density functional and many-body perturbation theory to calculate the quasiparticle band structures and electronic transport parameters of p-type SnSe both for the low-temperature Pnma and high-temperature Cmcm phases. The Pnma phase has an indirect band gap of 0.829 eV, while the Cmcm has a direct band gap of 0.464 eV. Both phases exhibit multiple local band extrema within an energy range comparable to the thermal energy of carriers from the global extrema. We calculated the electronic transport coefficients as a function of doping concentration and temperature for single-crystal and polycrystalline materials to understand the previous experimental measurements. The electronic transport coefficients are highly anisotropic and are strongly affected by bipolar transport effects at high temperature. Our results indicate that SnSe exhibits optimal thermoelectric performance at high temperature when doped in the 1019-1020 cm-3 range.

Shi, Guangsha; Kioupakis, Emmanouil

2015-02-01

332

Development of radiation hard edgeless detectors with current terminating structure on p-type silicon  

Energy Technology Data Exchange (ETDEWEB)

The development of edgeless Si detectors was stimulated by the tasks of the total pp cross-section study in the TOTEM experiment at the Large Hadron Collider at CERN. For this, the dead region at the detector diced side should be reduced below 50 {mu}m. This requirement is successfully realized in edgeless Si detectors with current terminating structure (CTS), which are now operating at LHC. The development of the experiment and future LHC upgrade need the elaboration of radiation hard version of edgeless Si detectors. The current investigation represents an extension in understanding on edgeless detectors operation and development of a new issue - edgeless detectors with CTS on p-type Si.

Verbitskaya, E., E-mail: elena.verbitskaya@cern.ch [Ioffe Physical-Technical Institute RAS, St. Petersburg (Russian Federation); Eremin, V. [Ioffe Physical-Technical Institute RAS, St. Petersburg (Russian Federation); Ruggiero, G. [CERN, Geneva (Switzerland)

2011-12-01

333

Ca28Ga11, a structure with three types of coordination polyhedra around the gallium atoms  

International Nuclear Information System (INIS)

Msub(r)=1889.2, orthorhombic, oI78, Imm2, a=5.324 (1), b=61.445 (7), c=7.488 (1) A, V=2449.6 (6) A3, Z=2, Dsub(x)=2.56 Mg m-3, Mo K?, lambda=0.7107 A, ?=9.03 mm-1, F(000)=1802, room temperature, R=0.051 for 900 reflections with F0>2sigma(F0). The Ca28Ga11 structure is characterized by three types of calcium polyhedra surrounding the gallium atoms: tricapped trigonal prisms, distorted cubes and distorted cubicosahedra (ten-vertex polyhedra similar to those found around Si in Co2Si). The linkage of these polyhedra gives rise to columns or slabs which alternate along the greatest axis of the cell. No Ga-Ga contacts are present. (orig.)

334

(1/2+1/2+1) cell structure type RF gun  

International Nuclear Information System (INIS)

In order to suppress the back bombardment of electrons in RF thermionic guns, a new kind of on axis coupled structure type RF gun was developed. It is composed of two half cells and a full cell. The first half cell is shortened and a half cell is inserted between the first half cell and the main accelerating cell to defocus the particles moving backwards with highest energy, thus the cathode back bombardment power is strongly reduced. For the field stability the ?/2 mode is chosen. The electromagnetic field analytical codes SUPERFISH and PAMELA are mainly used to do the calculation and simulation. The average back bombardment power is about 3.6 W, assuming the pulse width of 6 ?s and a repetition rate of 25 Hz. (author)

335

Is there a substitute for Structured Interview assessments of type A behaviour?  

Science.gov (United States)

Discriminant analyses, attempting to predict the Type A behaviour categorization achieved by means of the Structured Interview (SI), were carried out on the responses of 93 British males to the Jenkins Activity Survey and the Framingham Scale, together with information regarding their smoking habits, alcohol consumption, tea and coffee drinking and obesity levels, all of which have been suggested as risk factors for coronary heart disease. Where classification agreements with the SI were found to be above 50 per cent, classification functions based on the discriminant analyses were calculated from the responses of 36 additional male subjects. The actual SI categories were compared with the predicted categories for this second subject group. The results indicated that no reliable and robust alternative was available to predict the SI categorization. The implications of these results for the substitution of the SI by self-report questionnaires are discussed. PMID:4092017

O'Looney, B A; Harding, C M; Eiser, J R

1985-12-01

336

Fine structure of type-I edge-localized modes in the steep gradient region.  

Science.gov (United States)

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 5 x 10 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. PMID:16241662

Kurzan, B; Murmann, H D; Neuhauser, J

2005-09-30

337

OMP-type Algorithm with Structured Sparsity Patterns for Multipath Radar Signals  

CERN Document Server

A transmitted, unknown radar signal is observed at the receiver through more than one path in additive noise. The aim is to recover the waveform of the intercepted signal and to simultaneously estimate the direction of arrival (DOA). We propose an approach exploiting the parsimonious time-frequency representation of the signal by applying a new OMP-type algorithm for structured sparsity patterns. An important issue is the scalability of the proposed algorithm since high-dimensional models shall be used for radar signals. Monte-Carlo simulations for modulated signals illustrate the good performance of the method even for low signal-to-noise ratios and a gain of 20 dB for the DOA estimation compared to some elementary method.

Rebafka, Tabea; Charbit, Maurice

2011-01-01

338

Quantification of age-related changes in the structure model type and trabecular thickness of human tibial cancellous  

DEFF Research Database (Denmark)

Structure model type and trabecular thickness are important characteristics in describing cancellous bone architecture. It has been qualitatively observed that a radical change of trabeculae from plate-like to rod-like occurs in aging, bone remodeling, and osteoporosis. Thickness of trabeculae has 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 quantification of structure model type, such as plate, rod objects, or mixture of plates or rods. Trabecular thickness is calculated directly from 3-D images, which is especially important for an a priori unknown or changing structure. Furthermore, 2-D trabecular thickness was also calculated based on the plate model. Our results showed that structure model type changed towards more rod-like in the elderly, and that trabecular thickness declined significantly with age. These changes become significant after 80 years of age for human tibial cancellous bone, whereas both properties seem to remain relatively unchanged between 20 and 80 years. Although a fairly close relationship was seen between 3-D trabecular thickness and 2-D trabecular thickness, real 3-D trabecular thickness was significantly underestimated using 2-D method.

Ding, Ming; Hvid, I

2000-01-01

339

Effect of annealing temperature on the structural, photoluminescence and magnetic properties of sol-gel derived Magnetoplumbite-type (M-type) hexagonal strontium ferrite  

Science.gov (United States)

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 °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 °C was of single-phase with a space group of P6 3/mmc and lattice cell parameter values of a=5.882 Å and c=23.048 Å. EDS confirmed the composition of strontium ferrite calcined at 1000 °C being mainly of M-type SrFe 12O 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 °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.

Teh, Geok Bee; Wong, Yat Choy; Tilley, Richard D.

2011-09-01

340

Synthesis, structure and electrical properties of rare-earth doped apatite-type lanthanum silicates  

International Nuclear Information System (INIS)

Highlights: ? La9ASi6O27 ceramics were prepared by pressureless-sintering at 1923 K. ? La9ASi6O27 ceramics have apatite structure. ? The electrical conductivity of La9ASi6O27 increases with temperature. ? The highest conductivity is 1.03 × 10?2 S cm?1 at 1073 K for La9YbSi6O27. - Abstract: Rare-earth doped apatite-type lanthanum silicates, La9ASi6O27 (A = Nd, Sm, Gd, Yb), are synthesized by the high-temperature solid state reaction process. The microstructure and electrical properties of La9ASi6O27 ceramics are investigated by X-ray diffraction, scanning electron microscopy and complex impedance analysis. La9ASi6O27 ceramics are composed of hexagonal apatite-type structure and a very small amount of second phase La2SiO5. The total electrical conductivity of rare-earth doped lanthanum silicates obeys the Arrhenius relation, and gradually increases with increasing temperature from 673 K to 1173 K. Lanthanum silicates doped with Nd or Yb cations exhibit a higher total electrical conductivity than undoped lanthanum silicate. The highest total electrical conductivity value obtained at 773 K is 4.31 × 10?4 S cm?1 for La9NdSi6O27. AtO27. At 1073 K, La9NdSi6O27 and La9YbSi6O27 have a total electrical conductivity of 8.20 × 10?3 S cm?1 and 1.03 × 10?2 S cm?1, respectively, which are distinctly higher than undoped La10Si6O27 (5.84 × 10?3 S cm?1). However, the situation is reversed when Sm or Gd rare-earth cations are doped into lanthanum silicate.

341

Electronic Properties of p-Type ?-Doped GaAs Structure under Electric Field  

International Nuclear Information System (INIS)

We theoretically investigate the electronic properties of p-type ?-doped GaAs inserted into a quantum well under the electric field, at T = 0K.We will investigate the influence of the electric field on the ?-doping concentration for a uniform distribution. The depth of confining potential, the density profile, the Fermi level, the subband energies and the subband populations calculate by solving the Schrodinger and Poisson equations self consistently. It is found that the changes of the electronic properties are quite sensitive to the applied electric field and the doping concentration. As different from single n-type ?-doped structure, we see a replace between the ground light-hole (lh1) subband and the first excited heavy-hole (hh2) subband whenever the external electric field reaches a critical value. We find the abrupt changing of the subband energies and the subband populations whenever the applied electric field reaches a certain value. Also, it is found that the heavy-hole subbands contain many more energy states than the light-hole ones, the population of the heavy-hole levels represent approximately 91% of all the carriers

342

Crystal structure and equation of state of cotunnite-type zirconia  

International Nuclear Information System (INIS)

Cotunnite-type zirconia was studied by angular-dispersive X-ray diffraction in a diamond anvil cell after laser heating and 18 and 26.7 GPa. The structure, space group Pnam, Z = 4, was refined in situ at several different pressures on decompression and at ambient using the Rietveld method. The nine polyhedral Zr-O distances range from 2.10 to 2.56 angstrom at ambient pressure, which represents both an increase in the average and the minimum Zr-O distance relative to the monoclinic and orthorhombic lower-pressure forms. In addition, data obtained on an unheated sample indicate that the irreversible transition to the cotunnite phase began above 25 GPa and 70% conversion was achieved by 48.5 GPa. The compressibility of cotunnite-type zirconia was found to be slightly anisotropic and a Birch-Murnaghan equation-of-state fit of the p-V data yielded a bulk modulus of 332(8) GPa with a first derivative of 2.3(4), which is in good agreement with the value predicted by previous ab initio calculations

343

Structure and properties of die steels with carbon of the 5KhMNF type  

International Nuclear Information System (INIS)

A study was made of the relationship between the structure and properties of 5Kh2MNF-type steels the cooling rate after austenitization and the carbon content, the latter most heavily influencing the quenchability and quenching of steels, and, therefore, their toughness and plasticity. The most rational carbon content in the secondarily-hardened Kh2MNF-type stamp steels is 0.5%, which ensures a high heat resistance at 600 to 620 deg C; good tensile properties sigmasub(B)=145 to 150 kgs/mm2 and fracture toughness ?sub(H)=3.5 to 5.0 kgsxm/cm2 in case of circular (up to 500x500 mm) forged pieces. The 5Kh2MNF steel is recommended for large-size heavily loaded pressing and forging stamps used for hot deformation. The heat treatment conditions: quenching from 970 to 1000 deg C, cooling in oil, tempering at 580 to 620 deg C for a Rockwell hardness of 45 to 47 for the pressing stamps and 42 to 44 for the forging stamps

344

Ce3+ incorporated structural and magnetic properties of M type barium hexaferrites  

Science.gov (United States)

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 ?m. 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.

Pawar, R. A.; Desai, S. S.; Tamboli, Q. Y.; Shirsath, Sagar E.; Patange, S. M.

2015-03-01

345

Enhancing the three-dimensional electronic structure in 1111-type iron arsenide superconductors by H substitution  

Science.gov (United States)

The 1111-type iron arsenide hydride CaFe1-xCoxAsH was synthesized by high-pressure solid-state reaction, and its electronic structure and superconducting properties were investigated. Bulk superconductivity was observed at x = 0.09-0.26. A maximum superconducting critical temperature (Tc max) of 23 K was observed at x = 0.09. These values are in agreement with those of CaFe1-xCoxAsF. The calculated Fermi surface of CaFeAsH has a small three-dimensional (3D) hole pocket around the ? point. This is a result of weak covalent bonding between the As 4p and H 1s orbitals. No such covalency exists in CaFeAsF, because the energy level of the F 2p orbital is sufficiently deep to inhibit overlap with the As 4p orbital. The similar superconductivities of CaFe1-xCoxAsH and CaFe1-xCoxAsF are explained with the nesting scenario. The small 3D hole pocket of CaFe1-xCoxAsH does not significantly contribute to electron excitation. These findings encourage exploration of hydrogen-containing 1111-type iron-based materials with lower anisotropies and higher Tc applicable to superconducting wires and tapes.

Muraba, Yoshinori; Matsuishi, Satoru; Hosono, Hideo

2014-03-01

346

G33.6 + 0.1 - A shell type supernova remnant with unusual structure  

Science.gov (United States)

The morphology of Supernova Remnant G33.6 + 0.1 (Kes 79) has been studied in the X-rays with Einstein and in the radio wavelengths using the VLA. Multifrequency high resolution observations of the VLA at 327, 1500, and 5000 MHz are used to study the radio spectrum and polarization. The radio emission shows well formed outer shell structure and very bright central emission. Although the overall distribution of spectral index (about -0.6 to -0.75) is consistent with that of shell type remnants, the bright filamentary emission along the 'inner ring' has relatively flatter spectrum (alpha about -0.4). Both radio and X-rays show strong central emission; existence of a plerion near the center cannot be ruled out. The X-ray image does not show the characteristic limb brightening for shell type SNRs. The X-ray and radio morphology may be understood in terms of very thick shell and the bright central emission as due to reverse shock.

Velusamy, T.; Becker, R. H.; Seward, F. D.

1991-01-01

347

New phosphides with structures of the Zn2Fe12P7 and Hf2Co4P3 types  

International Nuclear Information System (INIS)

Crsytal structure of phosphides: Ti2Co12P7, Zr2Co12P7, Zr2Ni12P7, Nb2Co12P7, Nb2Co4P3 is studied by the roentgenographic analysis method. Compound roentgenograms, lattice parameters are presented. It is stated, that Ti2Co12P7, Zr2Co12P7, Zr2Ni12P7, Nb2Co12P7 have the structure of Zr2Fe12P7 type, and Nb2Co4P3 the structure of Hf2Co4P3 type

348

Analysis of the Population Structure of Anaplasma phagocytophilum Using Multilocus Sequence Typing  

Science.gov (United States)

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

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

349

Structural, dielectric and magnetic properties of Cd/Pb doped W-type hexaferrites  

Energy Technology Data Exchange (ETDEWEB)

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 K–573 K) and frequency (1 kHz–5 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.

Hooda, Ashima; Sanghi, Sujata, E-mail: sutkash@yahoo.com; Agarwal, Ashish; Dahiya, Reetu

2014-01-15

350

A method for evaluating structural transducers used in type B package testing  

International Nuclear Information System (INIS)

The Nuclear Waste Policy Act of 1982 (NWPA) tasked the US Department of Energy (DOE) with establishing and operating a comprehensive, integrated system for disposal of the nations spent nuclear fuel and high-level radioactive waste and established the Office of Civilian Radioactive Waste Management (OCRWM) within DOE to fulfill that responsibility. A key component of the disposal program is the development and operation of a transportation system to move the waste from its present locations to disposal facilities. A fleet of casks capable of transporting the waste by truck, rail, or barge is being developed. As a result of an agreement between DOE and the Nuclear Regulatory Commission (NRC), each 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 packages 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 fthese 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 manufacturers data under field and laboratory conditions were investigated

351

Structural, dielectric and magnetic properties of Cd/Pb doped W-type hexaferrites  

International Nuclear Information System (INIS)

W-type hexaferrites having compositions Ba(Zn0.5Cd0.5)2Fe16O27 (BZCFO) and Ba(Zn0.5Pb0.5)2Fe16O27 (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 K–573 K) and frequency (1 kHz–5 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 Cd2+ for tetrahedral sites and decrease in number of spin-down magnetic ions. - Highlights: • W type Ba(Zn0.5Cd0.5)2Fe16O27 and Ba(Zn0.5Pb0.5)2Fe16O27 hexaferrites were prepared. • BZPFO has more resistivity and low values of ?a.c., ?? and tan ? than BZCFO. • BZCFO has higher saturation magnetization and lower coercivity than BZPFO

352

The Electronic Structure of CdSe/CdS Core/Shell Seeded Nanorods: Type-I or Quasi-Type-II?  

OpenAIRE

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, ...

Eshet, Hagai; Gru?nwald, Michael; Rabani, Eran

2013-01-01

353

The L2 open reading frame of human papillomavirus type 1a encodes a minor structural protein carrying type-specific antigens.  

OpenAIRE

The proteins encoded by the open reading frames of papillomavirus genomes and the minor polypeptides detected in purified virions are still poorly defined. We show here by its expression in Escherichia coli that the open reading frame L2 of human papillomavirus type 1a codes for a minor structural protein of Mr 76,000. Antisera raised against a truncated L2-beta-galactosidase fusion protein in which the conserved N-terminal region of L2 is missing are type specific for human papillomavirus ty...

Komly, C. A.; Breitburd, F.; Croissant, O.; Streeck, R. E.

1986-01-01

354

Numerical model for the analysis of unbounded prestressed structures using the hybrid type finite element method  

International Nuclear Information System (INIS)

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)

355

The Russian oil industry re-structuration: towards the emergence of western type enterprises?  

International Nuclear Information System (INIS)

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)

356

Analysis of fluid-structure interaction in pressure suppression systems type 69 during steam condensation  

International Nuclear Information System (INIS)

The oscillations of German pressure suppression systems type 69 are investigated where the condensation chamber is located inside the spherical containment. Therefore, the pressure transients and oscillations affect directly the containment structure. The calculations show that consideration of the fluid inertia of the water pool reduces the eigenfrequencies significantly and increases the transient pressure loading. Without fluid inertia the smallest shell eigenfrequency is about 50 Hz. Including fluid inertia the smallest eigenfrequency is now in the order of 10 Hz, but the maximum pressure loading is about 40% higher than before. Strong stress gradients occur in the spherical containment close to the intersection with the bottom of the water pool. Therefore, high spatial resolution is required. Final results are presented in terms of admissible steam condensation scenarios where the stress reach their allowed upper limit. If these admissible scenarios cover all steam condensation events which may occur, the dimensions of the containment shell are adequate to blowdown loading. In this way the complex physics of steam condensation which has a certain statistic character and requires extensive experimental investigations is clearly distinguished from the fluid-structure interaction and shell dynamics problem which can be investigated on a mathematical basis. (orig./HP)

357

Fabrication and investigation of the structural properties of Cobalt doped M- type Strontium hexa ferrite nanoparticles  

International Nuclear Information System (INIS)

In this paper, nanoparticles of M- type strontium hexa ferrite doped with cobalt SrFe12-xCoxO19 (x= 0-2) were synthesized via sol- gel technique. Structural and morphological properties of the samples were analyzed by X- ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy. The XRD results showed that all of the samples of SrFe12-xCoxO19 with x?0.5 were single-phase. It seems that the Fe3+ ions are substituted by Co2+ ions in the crystallographic sites of the SrFe12O19 structure, but for the samples with x>0.5, the phase of CoFe2O4 is appeared in the samples and, suggests that the Co2+ ions also make distinct phase in the samples. The value of the lattice constant a is almost kept unchanged but that of lattice constant c decreases with increasing dopant contents. The FT-IR frequency bands in the range of 560-580 cm-1 and 430-470 cm-1 correspond to the formation of tetrahedral and octahedral clusters of the metal oxides in ferrites, respectively.

358

Prodrome of Paranoid Schizophrenia with Episodic Type of Course and Schizoaffective Structure of Manifest Episode  

Directory of Open Access Journals (Sweden)

Full Text Available Prodrome of paranoid schizophrenia with the episodic type of course (F20.1 and F20.2 according to ICD-10 and the schizoaffective structure of the episode was retrospectively studied. The pronounced and persistent affect, in particular depression in conjunction with hallucinations and/or delusions throughout the whole episode, served as the basis for an episode qualification as the schizoaffective structure. Diagnosis of schizophrenia was confirmed by the extremely low socio-demographic indicators at the time of the manifest episode, by the presence of catatonic or catatono-oneiroid symptoms in more than half of the patients, as well as an incongruence of hallucination plot and/or delusions against the dominant affect. In most cases, the affective symptoms were detected in clinical presentation of a prodrome and significantly more often in the form of depression, in comparison with bipolar and mixed affective disorders. Different clinical manifestations of negative symptoms were revealed in significantly more than half of the patients. The study showed that there is a significant frequency of negative manifestations in conjugation with depression in the prodrome.

Alexander S. Bobrov

2014-06-01

359

Waveguide-type optical isolator with in-plane magnetization structure  

Science.gov (United States)

A novel unidirectional mode converter, which has the advantage of a simple magnetization structure, is proposed for an application to a waveguide-type optical isolator. The proposed mode converter is constructed with in-plane magnetization in the whole device, where the magnetization component along a light propagation direction produces a mode conversion between TE0 and TM0 modes, while the magnetization perpendicular to the propagation direction provides a nonreciprocal phase shift to the TM0 mode. The unidirectional mode converter, in which, in the backward direction, 100% TE-TM mode conversion is produced but, in the forward direction, an input TE mode emerges as a TE mode, is realizable by virtue of the nonreciprocal phase shift of the TM0 mode. Design examples are shown by using the (LuBi)3Fe5O12 guiding layer / (YBi)3Fe5O12 cladding layer / Gd3Ga5O12 substrate structure. A typical length of the mode converter is 15.5 mm at the wavelength of 1.152 .tm for the guiding layer thickness of O.575jim and with the magnetization direction tilted by 87 degree from the light propagation direction in the film plane. A relatively large device length is reduced by using a magnetooptic material having a large first-order magnetooptic coefficient.

Mizumoto, Tetsuya; Naito, Yoshiyuki

1990-08-01

360

Magnetic spin structure of pyroxene-type MnGeO3  

International Nuclear Information System (INIS)

Polycrystalline MnGeO3 material was synthesized at 1473 K and ambient pressures using ceramic sintering techniques. Under these conditions the pyroxene-type compound crystallizes in the orthorhombic modification with space group Pbca, as determined from the refinement of the neutron diffraction data. The monoclinic modification, space group C 2/c, was also present at a level of 8.8(4) wt% and the magnetic structures for the two polymorphs at low temperatures have been found simultaneously. The monoclinic form orders magnetically below 34 K; the spin structure can be described using k = (0, 0, 0) in the magnetic space group C 2'/c, having an antiferromagnetic spin arrangement within and between the chains of M1 and M2 sites. The orthorhombic phase of MnGeO3 transforms to a magnetically ordered state with k = (0, 0, 0) and magnetic space group Pb'c'a below 12 K. Spins on M1 sites are aligned along the crystallographic a-axis with a slight non-collinear antiferromagnetic spin arrangement with and between the M1 chains. Spins on M2 sites are also antiferromagnetically coupled; however, one of the three different M1-M2 superexchange pathways within the band of M1 and M2 sites displays a ferromagnetic interaction, while the other two allow antiferromagnetic interaction.

361

Ratios of hardness numbers in calculations of static and cyclical strength of structural types of steels ??????????? ????? ????????? ? ???????? ?? ??????????? ? ??????????? ????????? ??????????????? ??????  

Directory of Open Access Journals (Sweden)

Full Text Available Results of calculations of values of static and cyclical strength of steels used in the structural design and based on the method of experimental and analytical coordination of hardness numbers are presented in the article. Strength measurements taken on the basis of the Rockwell method make it possible to research into the strength characteristics of small-size samples of steel in cases of restoration and inspection of the technical condition of the metalwork. Besides, the Rockwell method is universal and faster than the Brinell method.Thus, the availability of hardness values of small-size samples makes it possible to provide a definition of standard indicators of static and cyclical strength. Moreover, development of the definition of structural and power (synergetic criteria of reliability of metalsusing the equation of relative strength turn into reality. The solution to this equation ofuniform plastic deformations of dmakes it possible to identify S , S , W , W values.? B K P C The initial experimental value of the hardness number may be used to calculate avariety of static and cyclical properties of steel and to identify the standard strength group and the approximate steel type counterpart.????????? ?????????? ??????? ?? ??????????? ? ??????????? ????????? ?????? ???????????? ??????????? ?? ????????????????? ????????? ????????? HRB c ????????????? ????????? ? HB.???????? ???????????? ????? ??????? ????????? HRB ? HB ?????????? = 60 [(?RB/703 + 1]. (1?????????? ?? (1 ???? ?????????????????? ?????????? ????????? HB ?????????? HB ????????.?? ?????? ????????????????-?????????????? ???????????? HRB-HB ????? ?????????? ????????? ????????????? ???????.

Gustov Yuriy Ivanovich

2013-01-01

362

The Russian oil industry re-structuration: towards the emergence of western type enterprises?  

Energy Technology Data Exchange (ETDEWEB)

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)

Locatelli, C

1999-01-01

363

Structural and functional characterization of a novel type of ligand-independent RXR-USP receptor.  

Science.gov (United States)

Retinoid X receptor (RXR) and Ultraspiracle (USP) play a central role as ubiquitous heterodimerization partners of many nuclear receptors. While it has long been accepted that a wide range of ligands can activate vertebrate/mollusc RXRs, the existence and necessity of specific endogenous ligands activating RXR-USP in vivo is still matter of intense debate. Here we report the existence of a novel type of RXR-USP with a ligand-independent functional conformation. Our studies involved Tribolium USP (TcUSP) as representative of most arthropod RXR-USPs, with high sequence homology to vertebrate/mollusc RXRs. The crystal structure of the ligand-binding domain of TcUSP was solved in the context of the functional heterodimer with the ecdysone receptor (EcR). While EcR exhibits a canonical ligand-bound conformation, USP adopts an original apo structure. Our functional data demonstrate that TcUSP is a constitutively silent partner of EcR, and that none of the RXR ligands can bind and activate TcUSP. These findings together with a phylogenetic analysis suggest that RXR-USPs have undergone remarkable functional shifts during evolution and give insight into receptor-ligand binding evolution and dynamics. PMID:17673910

Iwema, Thomas; Billas, Isabelle M L; Beck, Yannick; Bonneton, François; Nierengarten, Hélène; Chaumot, Arnaud; Richards, Geoff; Laudet, Vincent; Moras, Dino

2007-08-22

364

Two Strandberg-type organophosphomolybdates: synthesis, crystal structures and catalytic properties.  

Science.gov (United States)

Two novel Strandberg-type organophosphomolybdate hybrid compounds [(Cu(H2O))2(?-bipy)2(C6H5PO3)2Mo5O15]n (1) and [(Cu(H2O)2)2(?-bipy)(C6H5PO3)2Mo5O15]n (2) (bipy = 4,4'-bipyridyl) were prepared under mild hydrothermal conditions and structurally characterized by physico-chemical and spectroscopic methods. Single crystal X-ray diffraction analysis reveals that compounds 1 and 2 are polyoxometalate-based Cu-coordination polymers with a three-dimensional framework. In 1, the Cu(2+) ions not only link [(C6H5PO3)2Mo5O15](4-) (abbreviated as {(C6H5P)2Mo5}) polyanions, but also act as connectors of bipy ligands to produce two symmetrical 1-D chains, all 1-D chains are further held together by polyanions to generate a 3-D network. In 2, each {(C6H5P)2Mo5} polyanion acting as a hexadentate ligand links four Cu(II)-bipy/H2O units, forming 2-D plane structures, which are further bridged by Cu(II)-bipy-Cu(II) fragments to generate a 3-D network. Their fluorescence properties and catalytic properties for the synthesis of cyclohexanone ethylene ketal were also investigated. PMID:25317986

Wang, Jian-Ping; Ma, Hong-Xin; Zhang, Lan-Cui; You, Wan-Sheng; Zhu, Zai-Ming

2014-12-01

365

Lattice dynamics and magnetism of metallic samarium in Sm-type and dhcp structured films  

Energy Technology Data Exchange (ETDEWEB)

The lattice dynamics of metallic samarium was unknown until recently. The high reactivity of Sm along with its large absorption cross section for thermal neutrons prohibited the application of inelastic neutron scattering, the standardly used method for determination of lattice dynamics. We determined the phonon density of states (DOS) of samarium by nuclear inelastic scattering on 149Sm. The experiments were performed at the end-station ID22N of the ESRF in Grenoble in a dedicated ultrahigh vacuum (UHV) system. 500 nm thick epitaxial Sm films exhibiting either the native for this metal Sm-type structure or the characteristic for the light lanthanides dhcp one were grown by molecular beam epitaxy following an elaborated procedure. In order to avoid oxidation and to reduce the multiphonon excitations the samples were investigated under UHV conditions and at 100 K. The magnetic properties of both structures were investigated by nuclear forward scattering in the temperature range 10 K - 300 K. From the phonon DOS a number of thermodynamic properties for this metal were determined.

Bauder, Olga; Stankov, Svetoslav [KIT, Karlsruhe (Germany); Barla, Alessandro [ALBA, Barcelona (Spain); Sergueev, Ilia; Rueffer, Rudolf [ESRF, Grenoble (France)

2012-07-01

366

Ab initio investigation of structure and stability of complex hydrides of L[MH3] type  

International Nuclear Information System (INIS)

The structure, stability, sections of potential surfaces (PS) of NaBeH3 and LiMgH3 complex hydrides are calculated in the framework of the non-empiric Hartry-Fock-Ruthan method using the two-exponential Roos-Siegbahn basis. The extreme PS points are clarified with a more complete and flexible two-exponential Huzinada-Dunning basis and polarization. It is shown that NaBeH3, LiMgH3, as well as the formerly studied LiBeH3 complex, belong to the amount of ''globally'' tough, but ''ilocally'' nontough molecular systems. Migration barriers on the way of shifting the outerspheric cation relatively to the anion decrease in the LiBeH3-NaBeH3 series, while they rise in the LiBeH3-LiMgH3 series. The correlation between the deformation of the anion nuclear carcass and the polarization of its electronic structure under the cation effect, is stated. The nature of the chemical bond in LMH3 complexes is investigated on the basis of analyzing the composition of localized molecuar orbitals. The problems of energetic and kinetic stability of LMH3 hydrides to different types of monomolecular decomposition, are discussed

367

Competing magnetic structures in the DySi FeB-type phase diagram  

International Nuclear Information System (INIS)

The temperature magnetic phase diagrams, of the dimorphic DySi compound, have been studied in terms of wave vectors in the range 1.5-45 K, by neutron diffraction. The polycrystalline sample consists of 26% of CrB-type (Cmcm no. 63, all atoms at 4c site: (0, y, 1/4)) and of 74% of FeB-type (Pnma no. 62, all atoms at 4c site: (x, 1/4, z)). The CrB-ordering is described by the wave vector: q1=(0, 0, 1/2) over the entire magnetically ordered regime with a uniaxial magnetic structure along the shortest axis c. The FeB-type magnetic phase diagram reveals three distinct regions of magnetic ordering below TN and one first order transition at T2=23.5 K (on heating). The ordering is described by two symmetry independent magnetic vectors q2=(0, 1/2, 1/6) and q3=(0, q3y, q3z) with a temperature variable length. At 1.5 K q3y?1/2 and q3z?1/11. The two phases coexist in the form of domains. They differ in the moment orientation of the q3 phase that deviates by ?22 deg. from the b-axis in the (0, 0, 1) plane. The low temperature range (LT) 1.5 K-T2 subdivides into two regions: (i) LT-1, between 1.5 K-T1 where the relative amount of the two phases remains unchanged and in (ii) LT-2: T1-T2 where the amount of the incommensurate q3 phase increases at the cost of the commensurate q2 amplitude modulated structb>2 amplitude modulated structure which remains unchanged but fully disappears at the first order transition at T2=23.5 K. The q3 phase undergoes minor changes until 22 K and gets destabilised at T2 where the q3z component jumps from the LT value q3z?1/11 to the HT value ?1/7 and the q3y component increases from 0.484(1) to 0.495(1). (iii) The high temperature (HT) range T2-TN (TN=40±1 K) is described by a single wave vector q3. The disproportionation of the HT magnetic phase q3 below T2 into two coexisting distinct phases q2, q3 down to 1.5 K is an unusual phenomenon, to our knowledge observed for the first time. Various mechanisms are discussed.

368

High-pressure synthesis, crystal structure and magnetic property of ilmenite-type FeGeO3  

International Nuclear Information System (INIS)

We synthesized well-crystallized ilmenite-type FeGeO3 to investigate its structural and magnetic properties. Ilmenite-type FeGeO3 were synthesized by high-pressure synthesis technique using a Kawai-type multi-anvil apparatus. Their structural and magnetic properties were examined by XRD analysis with Rietveld refinement, transmission electron microscopy, Mössbauer spectroscopy and SQUID-magnetization measurements. The subsequent annealing after the high-pressure synthesis was effective to improve the crystallinity of the ilmenite-type FeGeO3. The primary particle size of ilmenite-type FeGeO3 was ?15 nm. Some particles seemed to be covered with non- or poorly crystalline phase even after the annealing, and others showed a lamellar microstructure parallel to the (0 0 1) plane. Theilmenite-type FeGeO3 showed typical antiferromagnetic behavior with the Néel temperature of 79 K. - Graphical abstract: Crystal structure, transmission electron micrograph and temperature dependent susceptibility of ilmenite-type FeGeO3. Highlights: ? Ilmenite-type FeGeO3, a novel polymorphism of FeGeO3 was successfully synthesized. ? It was synthesized by using high pressure technique at 23.5 GPa at 500 °C. ? Subsequent annealing in vacuum was effective to improve the crystallinity. ? Its primary particle size was ?15 nm, and some grains had lamellar microstructure. ? It showed typical anti ? It showed typical antiferromagnetic behavior with the Néel temperature of 79 K.

369

A strategic analysis of the development of structural materials for proto-type reactors for fusion  

International Nuclear Information System (INIS)

Structural Materials Research and Development Subcommittee of Nuclear Materials Committee in Japan Atomic Energy Research Institute had made a study to propose a strategy how to expedite the research and development of structural materials for fusion reactors. This study was carried out along with the interim report of the Development of Structural Materials in Fusion Reactors proposed by Planning and Promotion Subcommittee of Fusion Council as well as with the Third Phase Basic Program of Fusion Research and Development settled by the Atomic Energy Commission. The present report was published to publicize the results of analyses of this study. In this report we focused mostly on the development of structural materials of blankets for tritium breeding because it is considered to be the most difficult task in the materials development due to severe conditions imposing on the blankets. We selected three candidate materials, namely, reduced low activation ferritic/ martensitic steel, SiC/SiC composites and Vanadium alloys, and elucidate the conditions in which these materials would be used as well as the design requirements for each material. Based on these conditions and requirements, we described the present status and the key issues of each material. For the development of the structural materials for the blankets, the keenest issue is the improvement and evaluation of radiation integrity and stability. Therefore, the necessity of radiation facilities, especially accelerator-type neutron sources with near fusion energy spectra was described. In addition the usage of fission reactors as irradiation facilities was also emphasized. In the processing of this reviewing we categorized reduced low activation ferritic/martensitic steel as advanced material, and SiC/SiC composites and Vanadium alloys as next-generation advanced material from the present status of developmental maturity. A periodical check and review in order to take the future progress in the development of these materials into account will examine the appropriateness of the present categories of these materials. In Chapters 1 to 5 the summary of our subcommittee's study was described, and in Chapter 6 the details of the above three candidates and irradiation facilities. (author)

370

Insights into the structural determinants of cohesin-dockerin specificity revealed by the crystal structure of the type II cohesin from Clostridium thermocellum SdbA.  

Science.gov (United States)

The plant cell wall degrading enzymes expressed by anaerobic microorganisms form large multienzyme complexes (cellulosomes). Cellulosomes assemble by the Type I dockerins on the catalytic subunits binding to the reiterated Type I cohesins in the molecular scaffold, while Type II dockerin-cohesin interactions anchor the complex onto the bacterial cell surface. Type I and Type II cohesin, dockerin pairs show no cross-specificity. Here we report the crystal structure of the Type II cohesin (CohII) from the Clostridium thermocellum cell surface anchoring protein SdbA. The protein domain contains nine beta-strands and a small alpha-helix. The beta-strands assemble into two elongated beta-sheets that display a typical jelly roll fold. The structure of CohII is very similar to Type I cohesins, and the dockerin binding site, which is centred at beta-strands 3, 5 and 6, is likely to be conserved in the two proteins. Subtle differences in the topology of the binding sites and a lack of sequence identity in the beta-strands that comprise the core of the dockerin binding site explain why Type I and Type II cohesins display such distinct specificities for their target dockerins. PMID:15913653

Carvalho, Ana L; Pires, Virginia M R; Gloster, Tracey M; Turkenburg, Johan P; Prates, José A M; Ferreira, Luís M A; Romão, Maria J; Davies, Gideon J; Fontes, Carlos M G A; Gilbert, Harry J

2005-06-24

371

A new type of antiferrodistortive structure in a double perovskite with Pb.  

Science.gov (United States)

We have found a new structural transition in Pb(2)MnReO(6) at 410 K. Above this temperature, Pb(2)MnReO(6) is cubic with disordered and dynamic atomic displacements manifested in the large thermal parameters of Pb and O atoms. Below 410 K, the antiferrodistortive shift of 2/3 of Pb(2+) cations away from the high-symmetry cubic site produces a new type of monoclinic cell. The unit cell expands at the transition and the heat capacity shows a peak with thermal hysteresis. These features agree with a first order transition. The entropy content of the transition is quite low indicating that the structural disorder has not been completely removed in the low temperature phase. The monoclinic phase of Pb(2)MnReO(6) shows thermally activated conductivity which does not vary when an external magnetic field is applied. A change in the slope of the resistivity curve, observed at the structural phase transition temperature, is related to a slight difference in the activation energy between both phases. It suggests that the condensation of the distortions likely affects the conduction mechanism. The isothermal magnetization measurements reveal the presence of ferromagnetic contributions below 85 K. The ac magnetic susceptibility shows a dynamic peak at 50 K and, in addition, zero-field-cooled and field-cooled magnetization curves diverge strongly below 80 K. These features might be signature of magnetic inhomogeneity. Magnetic loops, obtained at 5 K, do not show saturation in fields up to 9 T. Furthermore, the measured coercivity increases sharply at low temperature indicating an abrupt change in the magnetic anisotropy. We show that all these magnetic properties point out to a ferrimagnetic ordering of Mn and Re atoms in an intermediate valence state. PMID:21331421

Blasco, Javier; Lafuerza, Sara; García, Joaquín; Subías, Gloria; Sánchez, Ma Concepción; Cuartero, Vera; Stankiewicz, Jolanta

2011-04-01

372

Use of near infrared spectra to probe the chemical structure of type Ia supernovae  

Science.gov (United States)

Type Ia Supernovae (SNe Ia) are intrinsically interesting as very large explosions involving extreme and exotic physics. SNe Ia have become important cosmologically because their relative uniformity and high luminosity make them effective "standard candles" for distance estimates at large redshifts. We identified the near infrared (NIR; 0.8--2.5 mum) as a nearly unexplored and potentially very productive region for SNe Ia research. The NIR is a rich source of information about many explosion products that are obscured or blended at other wavelengths. We designed and implemented a systematic program to obtain NIR spectra from SNe Ia. We developed new tools and techniques to acquire, process, and interpret the data. We used synthetic models of SNe Ia explosions to aid the interpretation of results, and we used the observations to constrain the models. We obtained a large data set of NIR spectra that permits us to make important deductions about the chemical structure of SNe Ia. We show that NIR spectra have a uniform spectral evolution for normal SNe Ia. Thus our sample of forty-one spectra can be arranged in a time series to probe the chemical structure from the outer layers to deep inside the SN. We show that the burning products reside in distinct layers with no large scale mixing. We use multiple methods to demonstrate that burning consumes nearly the entire progenitor, making the amount of fuel the same for all SNe Ia explosions. That helps explain the homogeneity of SNe Ia. The two most popular explosion models produce different results that are detectable in the NIR. Our discoveries about the physical structure of SNe Ia agree well with the predictions of delayed detonation (DD) explosion models. Pure deflagration models are directly contradicted by our results and merger models are disfavored. Our results open the NIR window for SNe Ia research and we propose future directions for this field.

Marion, George Howard

2006-08-01

373

Structural design studies on a large pool type SFR of 1200MWe  

International Nuclear Information System (INIS)

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 ol. 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 a

374

Study on the seismic response of reactor vessel of pool type LMFBR including fluid-structure interaction  

International Nuclear Information System (INIS)

The pool type LMFBR reactor vessel contains many structures and a large amount of liquid sodium in it, in addition to being thin shell structure with large diameter. Therefore, the fluid-structure interaction will become more predominant, and should be considered for the seismic design of the pool type LMFBR. In this study, the fluid-structure interaction problems of the reactor vessel which has the bottom support arrangement as the core support system were investigated as well as the sloshing characteristics in the reactor vessel and also seismic response characteristics of the reactor vessel was studied experimentally and analytically using 3-D FEM code which took into account the fluid-structure interaction. (author)

375

Effect of annealing temperature on the structural, photoluminescence and magnetic properties of sol-gel derived Magnetoplumbite-type (M-type) hexagonal strontium ferrite  

International Nuclear Information System (INIS)

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 structurgnificant 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.

376

Effect of annealing temperature on the structural, photoluminescence and magnetic properties of sol-gel derived Magnetoplumbite-type (M-type) hexagonal strontium ferrite  

Energy Technology Data Exchange (ETDEWEB)

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.

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

377

Synthesis and crystal structures of novel LaOAgS-type alkaline earth – Zinc, manganese, and cadmium fluoride pnictides  

International Nuclear Information System (INIS)

Highlights: • Sight new alkaline earth – Mn, Zn, Cd fluoride pnictides were prepared. • All new compounds adopt the LaOAgS structure type. • Bond distances in their structures are transferable within 2–3%. • Very close similarities are observed in structural chemistry of LaOAgS- and HfCuSi2-type compounds of Mn, Cu, Zn, Ag, and Cd. -- Abstract: Systematic studies of the LaOAgS-type compounds among alkaline earth – Zn/Cd/Mn fluoride pnictides revealed the existence of new representatives SrFMnP, SrFMnAs, SrFMnSb, SrFZnAs, SrFZnSb, BaFZnAs, BaFCdP, and BaFCdAs. Similar to rare-earth oxide compounds and contrary to isolobal chalcogenides of Cu/Ag, not all possible compositions could be realized. No compound of the structure type is formed for calcium; strontium forms fluoride pnictides only with zinc and manganese, while for barium, new representatives are also formed with cadmium. This trend, which possibly has a geometrical origin, is corroborated by quantum chemical calculations. Formation of NdOZnP-type compounds also was not observed suggesting the structure to be characteristic only for rare earth – zinc oxide phosphides

378

Synthesis and crystal structures of novel LaOAgS-type alkaline earth – Zinc, manganese, and cadmium fluoride pnictides  

Energy Technology Data Exchange (ETDEWEB)

Highlights: • Sight new alkaline earth – Mn, Zn, Cd fluoride pnictides were prepared. • All new compounds adopt the LaOAgS structure type. • Bond distances in their structures are transferable within 2–3%. • Very close similarities are observed in structural chemistry of LaOAgS- and HfCuSi{sub 2}-type compounds of Mn, Cu, Zn, Ag, and Cd. -- Abstract: Systematic studies of the LaOAgS-type compounds among alkaline earth – Zn/Cd/Mn fluoride pnictides revealed the existence of new representatives SrFMnP, SrFMnAs, SrFMnSb, SrFZnAs, SrFZnSb, BaFZnAs, BaFCdP, and BaFCdAs. Similar to rare-earth oxide compounds and contrary to isolobal chalcogenides of Cu/Ag, not all possible compositions could be realized. No compound of the structure type is formed for calcium; strontium forms fluoride pnictides only with zinc and manganese, while for barium, new representatives are also formed with cadmium. This trend, which possibly has a geometrical origin, is corroborated by quantum chemical calculations. Formation of NdOZnP-type compounds also was not observed suggesting the structure to be characteristic only for rare earth – zinc oxide phosphides.

Charkin, Dmitri O., E-mail: charkin@inorg.chem.msu.ru; Urmanov, Arthur V.; Plokhikh, Igor V.; Korshunov, Alexander D.; Kuznetsov, Alexey N.; Kazakov, Sergey M.

2014-02-05

379

Design study of an IHX support structure for a POOL-TYPE Sodium-cooled fast reactor  

International Nuclear Information System (INIS)

The IHX (Intermediate Heat eXchanger) for a pool-type SFR (Sodium-cooled Fast Reactor) system transfers heat from the primary high temperature sodium to the intermediate cold temperature sodium. The upper structure of the IHX is a coaxial structure designed to form a flow path for both the secondary high temperature and low temperature sodium. The coaxial structure of the IHX consists of a central downcomer and riser for the incoming and outgoing intermediate sodium, respectively. The IHX of a pool-type SFR is supported at the upper surface of the reactor head with an IHX support structure that connects the IHX riser cylinder to the reactor head. The reactor head is generally maintained at the low temperature regime, but the riser cylinder is exposed in the elevated temperature region. The resultant complicated temperature distribution of the co-axial structure including the IHX support structure may induce a severe thermal stress distribution. In this study, the structural feasibility of the current upper support structure concept is investigated through a preliminary stress analysis and an alternative design concept to accommodate the IHTS (Intermediate Heat Transport System) piping expansion loads and severe thermal stress is proposed. Through the structural analysis it is found that the alternative design concept is effective in reducing the thermal stress and acquiring structural integrity

380

Singularity structures in Coulomb-type potentials in two-body Dirac equations of constraint dynamics  

International Nuclear Information System (INIS)

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-Co 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 ?-? splitting and effective chiral symmetry breaking. The TBDE formalism developed here may be used to study quarkonia in quark-gluon plasma environments.

381

Multilocus typing and population structure of Cryptosporidium from children in Zaragoza, Spain.  

Science.gov (United States)

A multilocus typing approach with eight variable-number tandem-repeat (VNTR) loci and the GP60 gene was used to analyze the inter- and intra-species variation of 44 Cryptosporidium isolates from pediatric patients in Zaragoza city (NE, Spain). Restriction and sequence analyses of the SSU rRNA gene revealed that Cryptosporidium transmission is mostly anthroponotic in this area, with the predominance of Cryptosporidium hominis (n: 41) over Cryptosporidium parvum (n: 3). GP60 subtyping showed limited genetic diversity and four subtypes were identified, including IbA10G2 (n: 35), IaA24R3 (n: 6), IIaA15G1R1 (n: 1) and IIaA15G2R1 (n: 2). Five out of eight VNTR loci showed a discriminatory power higher than the GP60 gene, although each locus had a predominant allele exhibited by more than 50% of isolates. All but four alleles were associated to either C. hominis or C. parvum and linked alleles at different loci were found. Multilocus typing substantially increased the discriminatory power (Hunter-Gaston index: 0.807, 95% CI, 0.683-0.926) and revealed that genetic diversity is much higher than that reported by GP60 sequencing, since 17 multilocus subtypes (MLTs) were identified. Nearly half of the specimens were allocated to a single major MLT. However, no more than three specimens were allocated to each of the remaining MLTs. Both phylogenetic and population analyses revealed a population clustering of C. hominis according to the GP60 subtype, which indicates the robustness of this marker to differentiate genetic subpopulations. Subpopulations had an overall clonal genetic structure, although traces of genetic flow between them were also observed. PMID:25660036

Ramo, Ana; Quílez, Joaquín; Vergara-Castiblanco, Claudia; Monteagudo, Luis; Del Cacho, Emilio; Clavel, Antonio

2015-04-01

382

Structure of the C-type lectin carbohydrate recognition domain of human tetranectin  

DEFF Research Database (Denmark)

Tetranectin (TN) is a C-type lectin involved in fibrinolysis, being the only endogenous ligand known to bind specifically to the kringle 4 domain of plasminogen. TN was originally isolated from plasma, but shows a wide tissue distribution. Furthermore, TN has been found in the extracellular matrix of certain human carcinomas, whereas none or little is present in the corresponding normal tissue. The crystal structure of full-length trimeric TN (2.8 A resolution) has recently been published [Nielsen et al. (1997). FEBS Lett. 412, 388-396]. The crystal structure of the carbohydrate recognition domain (CRD) of human TN (TN3) has been determined separately at 2.0 A resolution in order to obtain detailed information on the two calcium binding sites. This information is essential for the elucidation of the specificity of TN towards oligosaccharides. TN3 crystallizes as a dimer, whereas it appears as a monomer in solution. The overall fold of TN3 is similar to other known CRDs. Each monomer is built of two distinct regions, one region consisting of six beta-strands and two alpha-helices, and the other region is composed of four loops harboring two calcium ions. The calcium ion at site 1 forms an eightfold coordinated complex and has Asp116, Glu120, Gly147, Glu150, Asn151, and one water molecule as ligands. The calcium ion at site 2, which is believed to be involved in recognition and binding of oligosaccharides, is sevenfold coordinated with ligands Gln143, Asp145, Glu150, Asp165, and two water molecules. One sulfate ion has been located at the surface of TN3, forming contacts to Glu120, Lys148, Asn106 of a symmetry-related molecule, and to an ethanol molecule.

Kastrup, J S; Nielsen, B B

1998-01-01

383

Monazite-type ceramics for conditioning of minor actinides. Structural characterization and properties  

Energy Technology Data Exchange (ETDEWEB)

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

Babelot, Carole

2013-07-01

384

Structure and property investigations of spinel type LiMnTiO4  

International Nuclear Information System (INIS)

Spinel type LiMn204 was considered an attractive cathode material for rechargeable lithium ion batteries. Doping of LiMn204 with tetravalent titanium was proposed in order to improve the capacity and charge-discharge capability. Since the first study of LiMnTiO4 in 1986, there has been an ongoing debate on the metal ion ordering in the structure. Most recently Arillo et al. reported a comprehensive study on the effect of different sintering temperatures and cooling regimes on the structure and metal ion ordering of LiMnTiO4. They concluded that Li=+Ti4[Li+Mn3+Ti4+]04 (Fd3m), where square brackets denote the octahedral sites, was formed upon slow cooling. Whereas Li+Mn2+[Li+Mn3+/4+Ti4+]04 (P4332) was formed alongside the main F3m phase upon quenching. In this contribution, LiMnTiO4 compounds were prepared through solid state synthesis with two cooling regimes: quenching in liquid N2 and slow cooling. Synchrotron X-ray and neutron powder diffraction refinements presented the quenched LiMnTiO4 as spinel (Fd3m) with cation distribution of Li0.65TiO.35[Li0.35MnTi0.65]04, whilst partial phase transition from Fd3m to P4332 occurred on slow cooling of LiMnTiO4, contradicting Arillo et al. The metal ion occupancy of the P4332 phase was not able to be refined due to the relatively small amount present. Magnetic field dependence measurements of the compounds indicated that Mn3+ contributed to the effective moment predominantly. Mn and Ti K edge X-ray absorption near edge structure spectra revealed the presence of Mn3+ and Ti4+ on the octahedral sites for LiMnTiO4, regardless of the cooling regimes. This combination of magnetic measurements and XANES data further contradicts the metal ion ordering found by Arillo et al.

385

Evolution of Structure in Late-type Spiral Galaxies I: Ionized Gas Kinematics in NGC 628  

CERN Document Server

We study two dimensional Fabry-Perot interferometric observations of the nearby face-on late-type spiral galaxy, NGC 628, in order to analyse the ionized gas component of the interstellar medium. Covering the galaxy out to a radius larger than 12 kpc, and with a spatial sampling of 1.6 arcsec, we investigate the large-scale dynamics as well as feedback from individual HII regions into their surrounding medium. We study the role of gravitational perturbations along with that of external triggers which can disturb the kinematics and morphology of NGC 628. We verify the presence of an inner rapidly rotating disc-like component in NGC 628, which we interpret as caused by slow secular evolution of the large-scale spiral arms and oval structure. In combination with auxiliary data, we find indication for that gas is falling in from the outer parts towards the central regions, where a nuclear ring has formed at the location of the inner Lindblad resonance radius of an m=2 perturbation which could help build a pseudo-...

Fathi, K; Zurita, A; Relano, M; Knapen, J H; Daigle, O; Hernández, O; Carignan, C; Fathi, Kambiz; Beckman, John E.; Zurita, Almudena; Relano, Monica; Knapen, Johan H.; Daigle, Olivier; Hernandez, Olivier; Carignan, Claude

2007-01-01

386

Structure of flora after ten years land lying fallow on two types of soil  

Directory of Open Access Journals (Sweden)

Full Text Available In the paper the structure of flora in 1st and 10th year of arable land lying fallow has been presented. Phytosociological observations were carried out on two fields lying on different soil (rendzina and podsolic soil. Analyses of flora concerned geografical and historical groups, origin of apophytes as well as living forms of plants. The conducted research showed that in the flora of fallows, with the time of exclusion of arable land from the agricultural use, there was incease in the number of apophytes and decrease of antropophytes, especially archeophytes, independent of types of soil. Ruderal apophytes, dominating in early stage of succession, gave way to meadow apophytes on the heavy soil, whereas segetal apophytes took place of forest and bushwood species on the light soil. In phytocenosis of multi-year fallows on the light and heavy soil, among the living forms, the most numerous were represented by hemicryptophytes, which replaced the dominating terophytes on the one-year fallow.

Joanna Kurus

2006-12-01

387

Structure and function of invertebrate Kazal-type serine proteinase inhibitors.  

Science.gov (United States)

Proteinases and proteinase inhibitors are involved in several biological and physiological processes in all multicellular organisms. The proteinase inhibitors function as modulators for controlling the extent of deleterious proteinase activity. The Kazal-type proteinase inhibitors (KPIs) in family I1 are among the well-known families of proteinase inhibitors, widely found in mammals, avian and a variety of invertebrates. Like those classical KPIs, the invertebrate KPIs can be single or multiple domain proteins containing one or more Kazal inhibitory domains linked together by peptide spacers of variable length. All invertebrate Kazal domains of about 40-60 amino acids in length share a common structure which is dictated by six conserved cysteine residues forming three intra-domain disulfide cross-links despite the variability of amino acid sequences between the half-cystines. Invertebrate KPIs are strong inhibitors as shown by their extremely high association constant of 10(7)-10(13)M(-1). The inhibitory specificity of a Kazal domain varies widely with a different reactive P(1) amino acid. Different invertebrate KPI domains may arise from gene duplication but several KPI proteins can also be derived from alternative splicing. The invertebrate KPIs function as anticoagulants in blood-sucking animals such as leech, mosquitoes and ticks. Several KPIs are likely involved in protecting host from microbial proteinases while some from the parasitic protozoa help protecting the parasites from the host digestive proteinase enzymes. Silk moths produce KPIs to protect their cocoon from predators and microbial destruction. PMID:19995574

Rimphanitchayakit, Vichien; Tassanakajon, Anchalee

2010-04-01

388

Efficient campaign-type structural health monitoring using wireless smart sensors  

Science.gov (United States)

Wireless Smart Sensor Networks (WSSNs) have attracted great attention in recent years for Structural Health Monitoring (SHM), enabling better understanding of the dynamic behavior of large scale civil infrastructures through dense deployment of sensors. With a fraction of the deployment time and cost compared with wired SHM systems, WSSNs can serve as ideal systems for campaign-type monitoring for (i) short-term, in-service performance evaluation, (ii) postdisaster condition assessment, (iii) design optimization of long-term SHM system before permanent deployment, etc. Efficient data collection is generally needed in campaign monitoring due to limited operation time. A number of improvements have been made to the Illinois SHM Project (ISHMP) Services Toolsuite to facilitate efficient data collection for campaign monitoring. A post-sensing time synchronization scheme is proposed to reduce the latency of data collection while maintaining high accuracy of synchronization of collected data. A multi-hop bulk data transfer approach using multiple RF channels is also implemented to achieve high data throughput.

Li, Jian; Nagayama, Tomonori; Mechitov, Kirill A.; Spencer, Billie F., Jr.

2012-04-01

389

Probing the 2-D kinematic structure of early-type galaxies out to 3 effective radii  

CERN Document Server

We detail an innovative new technique for measuring the 2-D velocity moments (rotation velocity, velocity dispersion and Gauss-Hermite coefficients h$_3$ and h$_4$) of the stellar populations of galaxy halos using spectra from Keck DEIMOS multi-object spectroscopic observations. The data are used to reconstruct 2-D rotation velocity maps. Here we present data for five nearby early-type galaxies to ~3 effective radii. We provide significant insights into the global kinematic structure of these galaxies, and challenge the accepted morphological classification in several cases. We show that between 1-3 effective radii the velocity dispersion declines very slowly, if at all, in all five galaxies. For the two galaxies with velocity dispersion profiles available from planetary nebulae data we find very good agreement with our stellar profiles. We find a variety of rotation profiles beyond 1 effective radius, i.e rotation speed remaining constant, decreasing \\emph{and} increasing with radius. These results are of pa...

Proctor, Robert N; Romanowsky, Aaron J; Brodie, Jean P; Strader, Jay; Spolaor, Max; Mendel, J Trevor; Spitler, Lee

2009-01-01

390

New cadmium and rare-earth metal molybdates with scheelite-type structure  

Energy Technology Data Exchange (ETDEWEB)

New cadmium and rare-earth metal molybdates with the formula Cd{sub 0.25}RE{sub 0.50}MoO{sub 4} (RE = Pr, Nd, Sm-Dy) were synthesized by the solid-state reaction of CdMoO{sub 4} with corresponding RE{sub 2}(MoO{sub 4}){sub 3}. The obtained compounds crystallize in the scheelite-type structure. They were characterized here by XRD, DTA-TG, IR and EPR methods. The Cd{sub 0.25}RE{sub 0.50}MoO{sub 4} compounds showed solubility in CdMoO{sub 4} forming the Cd{sub x}RE{sub 2-2x}(MoO{sub 4}){sub 3-2x} (0.50 < x < 1.00) solid solutions. It can be found from EPR measurements of the samples with volatile Gd{sup 3+} ions content, that Gd{sup 3+} ions can be located at sites of octahedral symmetry, and both temperature and gadolinium content have an influence on local magnetic interaction and relaxation processes of Gd{sup 3+} ions.

Tomaszewicz, E., E-mail: tomela@zut.edu.pl [West Pomeranian University of Technology, Department of Inorganic and Analytical Chemistry, Al. Piastow 42, 71-065 Szczecin (Poland); Kaczmarek, S.M.; Fuks, H. [West Pomeranian University of Technology, Institute of Physics, Al. Piastow 17, 70-310 Szczecin (Poland)

2010-08-01

391

NMR solution structure of the RNA-binding peptide from human immunodeficiency virus (type 1) Rev  

Energy Technology Data Exchange (ETDEWEB)

NMR spectroscopy has been used to solve the three-dimensional solution structure of a minimal RNA-binding domain of the Rev protein from the human immunodeficiency virus (type 1), an essential regulatory protein for viral replication. The presence of 10 arginine residues in the 17-residue peptide Rev{sub 34-50} caused significant problems in assignment of the NMR spectra. To improve spectral resolution, the peptide was synthesized with an alanine replacing a nonessential arginine and with selectively {sup 15}N-labeled residues. Contrary to Chou-Fasman modeling predictions an {alpha}-helix was detected in both water and 20% trifluorethanol (TFE) and was found to span residues that constitute the RNA-binding and nuclear-localizing domains of Rev. The sequence-specific information provided by the NMR data gives a full description of the solution conformation of Rev{sub 34-50} which serves as a template for investigating binding of the peptide to RNA from the Rev response element (RRE). Preliminary modeling suggests that the helix can fit neatly into the expanded major groove of the RRE where interactions between the peptide side chains and the RNA can be identified. These data may aid the construction of a suitable pharmacophore model for the rational design of molecules that block Rev-RNA binding and inhibit HIV replication. 40 refs., 9 figs., 2 tabs.

Scanlon, M.J.; Fairlie, D.P.; Craik, D.J. [Univ. of Queensland, St. Lucis (Australia)] [and others

1995-07-04

392

Coronal lines and the structure of an upper atmosphere of T Tauri type stars  

International Nuclear Information System (INIS)

The relations are obtained, allowing to determine the parameters of stellar coronae from intensities of the strongest forbidden coroanal lines. A joint analysis of the UV and X-ray observations together with the results of searches of coronal lines in the case of T Tau stars is performed. It is shown that thermal conductivity plays a negligible role in the energy balance in the atmospheres of these stars at T> or approximately 2x105 K. The prospects for the search of coronal lines in the spectra of T Tau stars are discussed. It is expedient to look for Si 8 1445.8 A and Fe 19 1118.1 A lines in UV range according to spectrograms obtained under condtions of high resolution. The value of equivalent width on the order of 20-30 mA can be expected for Fe 13 107456 A line in infrared range. Reliable conclusions about the structure of the upper atmosphere of T Tauri type stars and the properties of near-star shell can be obtained only after synchronous observation in all spectral ranges using the best of available instruments

393

Human liver-type arginase gene: Structure of the gene and analysis of the promoter region  

Energy Technology Data Exchange (ETDEWEB)

The gene for human liver-type arginase, a urea cycle enzyme, was cloned and the structure was determined. This gene is 11.5 kilobases long and is split into 8 exons. The cap site was determined by nuclease S1 mapping and primer extension. A TATA box-like sequence is located 28 bases upstream from the cap site, and a sequence similar to the binding sites of the transcription factor CTF/NF1, a CAAT box-binding protein, is located 72 bases upstream. In the 5{prime} end region, sequences resembling the glucocorticoid responsive elements, the cAMP responsive elements, and the enhancer core sequences are present. The immediately 5{prime} flanking region of the human gene up to position {minus}105 is 84% identical with the corresponding segment of the rat gene. In this region of the human gene, one DNase I-protected area and several hypersensitive cleavage sites were detected by footprint analysis, using nuclear extracts from the rat liver. The protected area contains the sequence similar to the binding sites of CTF/NF1 and also overlaps with the sequence resembling the glucocorticoid responsive elements.

Takiguchi, Masaki; Haraguchi, Yougo; Mori, Masataka (Kumamoto Univ. Medical School (Japan))

1988-09-26

394

Structure–performance relationships for cantilever-type piezoelectric energy harvesters  

International Nuclear Information System (INIS)

This study provides comprehensive analysis of the structure–performance relationships in cantilever-type piezoelectric energy harvesters. It provides full understanding of the effect of all the practical global control variables on the harvester performance. The control variables considered for the analysis were material parameters, areal and volumetric dimensions, and configuration of the inactive and active layers. Experimentally, the output power density of the harvester was maximum when the shape of the beam was close to a square for a constant bending stiffness and a fixed beam area. Through analytical modeling of the effective stiffness for the piezoelectric bimorph, the conditions for enhancing the bending stiffness within the same beam volume as that of a conventional bimorph were identified. The harvester configuration with beam aspect ratio of 0.86 utilizing distributed inactive layers exhibited an giant output power of 52.5?mW and power density of 28.5?mW?cm?3 at 30?Hz under 6.9?m?s?2 excitation. The analysis further indicates that the trend in the output power with varying damping ratio is dissimilar to that of the efficiency. In order to realize best performance, the harvester should be designed with respect to maximizing the magnitude of output power.

395

Structure–performance relationships for cantilever-type piezoelectric energy harvesters  

Energy Technology Data Exchange (ETDEWEB)

This study provides comprehensive analysis of the structure–performance relationships in cantilever-type piezoelectric energy harvesters. It provides full understanding of the effect of all the practical global control variables on the harvester performance. The control variables considered for the analysis were material parameters, areal and volumetric dimensions, and configuration of the inactive and active layers. Experimentally, the output power density of the harvester was maximum when the shape of the beam was close to a square for a constant bending stiffness and a fixed beam area. Through analytical modeling of the effective stiffness for the piezoelectric bimorph, the conditions for enhancing the bending stiffness within the same beam volume as that of a conventional bimorph were identified. The harvester configuration with beam aspect ratio of 0.86 utilizing distributed inactive layers exhibited an giant output power of 52.5?mW and power density of 28.5?mW?cm{sup ?3} at 30?Hz under 6.9?m?s{sup ?2} excitation. The analysis further indicates that the trend in the output power with varying damping ratio is dissimilar to that of the efficiency. In order to realize best performance, the harvester should be designed with respect to maximizing the magnitude of output power.

Cho, Kyung-Hoon, E-mail: kh97.cho@samsung.com, E-mail: spriya@vt.edu; Park, Hwi-Yeol; Heo, Jin S. [Samsung Advanced Institute of Technology, Samsung Electronics, Yongin 446-712 (Korea, Republic of); Priya, Shashank, E-mail: kh97.cho@samsung.com, E-mail: spriya@vt.edu [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Virginia 24061 (United States)

2014-05-28

396

Precision measurements of large scale structure with future type Ia supernova surveys  

International Nuclear Information System (INIS)

Type Ia supernovae are currently the best known standard candles at cosmological distances. In addition to providing a powerful probe of dark energy they are an ideal source of information about the peculiar velocity field of the local universe. Even with the very small number of supernovae presently available it has been possible to measure the dipole and quadrupole of the local velocity field out to z?0.025. With future continuous all-sky surveys like the Large Synoptic Survey Telescope (LSST) project the luminosity distances of tens of thousands of nearby supernovae will be measured accurately. This will allow for a determination of the local velocity structure of the universe as a function of redshift with unprecedented accuracy, provided the redshifts of the host galaxies are known. Using catalogues of mock surveys we estimate that future low redshift supernova surveys will be able to probe ?8 to a precision of roughly 5% at 95% C.L. This is comparable to the precision in future galaxy and weak lensing surveys, and with a relatively modest observational effort it will provide a crucial cross-check on future measurements of the matter power spectrum

397

Depleted cores, multi-component fits, and structural parameter relations for luminous early-type galaxies  

CERN Document Server

New surface brightness profiles from 26 early-type galaxies with partially depleted cores have been extracted from the full radial extent of Hubble Space Telescope images, giving us a total sample of 31 such core-Sersic galaxies. We have carefully quantified the radial stellar distributions of the elliptical galaxies using the core-Sersic model whereas for the lenticular galaxies a core-Sersic bulge plus an exponential disc model gives the best representation. We additionally caution about the excessive use of multiple Sersic functions for decomposing galaxies. The structural parameters obtained from our fitted models are used to update several `central' as well as `global' galaxy scaling relations. We find near-linear relations between the break radius R_b and the spheroid luminosity L such that R_b ~ L^(1.13 +/- 0.13), and with the supermassive black hole mass M_BH such that R_b ~ M_BH^(0.83+/- 0.21). This is internally consistent with the notion that major, dry mergers add the stellar and black hole mass i...

Dullo, Bililign T

2013-01-01

398

Resistance of structure and antigenic determinations of native hexon of type 1 adenovirus to protease  

International Nuclear Information System (INIS)

Native hexon capsomers (trimers) of human type 1 adenovirus (Ad hl) were labeled with 125I and subjected to cleavage by trypsin, chymotrypsin, and papain. The hydrolysis of the hexon of Ad 1 by these enzymes is limited and in each case a set of relatively large fragments, which are not cleaved during prolonged hydrolysis, is formed. The degree of hydrolysis of the Ad hl hexon increases in the order trypsin < chymotrypsin < papain, the molecular weight of the largest fragments constituting 80,000, 40,000, and 32,000, respectively. At a decreased temperature all the large fragments of the hydrolysates obtained are confined in aggregates (the cores of the hexon), similar in structure to the original hexon trimers, the papain core of the Ad hl hexon being the most stable during electrophoresis in polyacrylamide gel and the chymotrypsin core being the least. A radioimmunoprecipitation analysis showed that denatured fragments of the tryptic, chymotryptic, and papain hydrolysates do not possess antigenic activity

399

Benthic assemblages on artificial reefs in the northwestern Adriatic Sea: Does structure type and age matter?  

Science.gov (United States)

The use of artificial reefs is on the rise worldwide. While their fish aggregating effects are well known, the epibenthic assemblages have been poorly investigated. Two types of artificial reefs (pyramids of concrete slabs and bundles of concrete tubes) have been deployed out of the Po River Delta in 2006 and 2010. The epibenthic assemblages were investigated in 2009 and 2012. Benthic assemblages on both structure typologies were dominated by species tolerating high sedimentation rates. Dissimilarities were found among assemblages with different ages, and, in less extend, between reef typologies. Colonisation by Mytilus galloprovincialis and other major space occupiers did not follow a clear succession pattern and was not affected by reef typology. Species colonisation was likely driven by variability in environmental conditions and recruitment processes rather than by reef typology. This study suggests that environmental features of the deployment sites should be carefully considered in planning and designing artificial reefs, especially in eutrophic and turbid coastal waters, exposed to high river loads. PMID:25569857

Ponti, Massimo; Fava, Federica; Perlini, Rossella Angela; Giovanardi, Otello; Abbiati, Marco

2015-03-01

400

On the cosmology of type IIA compactifications on SU(3)-structure manifolds  

International Nuclear Information System (INIS)

We study cosmological properties of type IIA compactifications on orientifolds of SU(3)-structure manifolds with non-vanishing geometric flux. These compactifications give rise to effective 4D N = 1 supergravity theories that do not fall under some recently-proven no-go theorems against de Sitter vacua and slow-roll inflation. Focusing on a well-understood class of models based on coset spaces, however, we can use a refined no-go theorem that rules out de Sitter vacua and slow-roll inflation in all but one case. The refined no-go theorem uses the dilaton and a specific linear combination of the Kaehler moduli, which is different from the overall volume modulus. It puts a lower bound on the first slow-roll parameter: ? ? 2. The only case not ruled out is the manifold SU(2) x SU(2), for which we indeed find critical points with ? numerically zero. However, all the points we could find have a tachyon corresponding to an eta-parameter ? ?< -2.4.

401

Dust grains and the structure of steady C-type magnetohydrodynamic shock waves in molecular clouds  

CERN Document Server

I examine the role of dust grains in determining the structure of steady, cold, oblique C-type shocks in dense molecular gas. Gas pressure, the inertia of the charged components, and changes in ionisation are neglected. The grain charge and rate coefficients for electron-neutral and grain-neutral elastic scattering are assumed constant at values appropriate to the shock interior. An MRN size distribution is accounted for by estimating an effective grain abundance and Hall parameter for single-size grains. A one-parameter family of intermediate shocks exists for each shock speed v_s between the intermediate signal speed v_A cos theta and sqrt{2} v_A cot theta, where v_A is the preshock Alfven speed and theta is the angle between the preshock magnetic field and the normal to the shock front. In addition, there is a unique fast shock for each v_s > v_A. If the preshock density n_H is greater than about 10^5 cm^-3 and the preshock magnetic field satisfies B(mG) less than about n_H(10^5 cm^-3) grains are partially...

Wardle, M

1998-01-01

402

Influence of Rotor Structure and Number of Phases on First and Second Order Characteristics of TOYOTA PRIUS Electrical Machine Type  

OpenAIRE

This paper investigates the influence of the rotor structure on torque and Flux weakening region of V-shape IPM machine from TOYOTA PRIUS type, more specifically, keeping always the same magnet volume, we study the effect of the open angle between the two magnet segments of each V-shape pole on the machine performance. Moreover, in order to examine the impact of phase number on the machine characteristics, PRIUS structure is transformed into 5-phase machine of the same type and dimensions. As...

Aslan, Bassel; Korecki, Julien; Vigier, Thimote?; Semail, Eric

2011-01-01

403

Correlation between arterial vascularity by radiologic study and structural histopathologic type in resected hepatocellular carcinoma(HCC)  

International Nuclear Information System (INIS)

To analyze the correlation between dynamic vascular pattern and structural histologic type of HCC. The materials consisted of 35 cases of HCC, which could be classified by structural histologic type and had available preoperative arterial dominant images. Excluding one case of pseudo glandular type, we compared structural histologic type of the tumors(trabecular group; 13 cases, mixed group; 10 cases, and non trabecular group; 11 cases) with dynamic vascular pattern such as degrees of tumor staining, severity of tumor vessels on hepatic angiography, and with enhancing degrees of early phase relative to late phase on two-phase incremental bolus dynamic CT. In hepatic angiogram, trabecular group showed stronger tumor staining and more prominent dilatation and irregularity of tumor vessels than those of non trabecular group, and In two-phase incremental bolus dynamic CT, and trabecular group showed more prominent tumor enhancement in early phase than those in late phase. The trabecular type(typical) and non-trabecular type of HCC showed radiologically different vascular patterns and therefore we believe that this maybe the basis with which diagnosis and treatment policy of radiologically atypical HCC could be made

404

NMR analysis shows that a b-type variant of Hydrogenobacter thermophilus cytochrome c552 retains its native structure.  

Science.gov (United States)

Conversion of Hydrogenobacter thermophilus cytochrome c(552) into a b-type cytochrome by mutagenesis of both heme-binding cysteines to alanines significantly reduces the stability of the protein (Tomlinson, E. J., and Ferguson, S. J. (2000) Proc. Natl. Acad. Sci. U. S. A. 97, 5156-5160). To understand the effects of this change on the structure and dynamics of the protein, hetero-nuclear (15)N-edited NMR techniques have been used to characterize this b-type variant. The backbone (15)N, (1)H(N), and (1)H(alpha), and (1)H(beta) resonances of the protein have been assigned. Analysis of (3)J(HN)alpha coupling constants, nuclear Overhauser enhancement intensities, and chemical shift index data demonstrates that the four alpha-helices present in the wild-type protein are retained in the b-type variant. Comparison of the chemical shifts for the b-type and wild-type proteins indicates that the tertiary structures of the two proteins are closely similar. Some subtle differences are, however, observed for residues in the N-terminal region and in the vicinity of the heme-binding pocket. Hydrogen exchange studies show that there are 25 backbone amide protons that exchange very slowly in the b-type variant and confirm that the fluctuations within the b-type protein are of a similar extent to those in the wild-type protein. These data demonstrate the notable retention of the native secondary structure and tertiary fold despite the absence of covalent linkages between the heme group and the protein. PMID:14726539

Wain, Rachel; Redfield, Christina; Ferguson, Stuart J; Smith, Lorna J

2004-04-01

405

Quantum cluster algebra structures on quantum Grassmannians and their quantum Schubert cells: the finite-type cases  

CERN Document Server

We exhibit quantum cluster algebra structures on quantum Grassmannians $K_q[Gr(2,n)]$ and their quantum Schubert cells, as well as on $K_q[Gr(3,6)]$, $K_q[Gr(3,7)]$ and $K_q[Gr(3,8)]$. These cases are precisely those where the quantum cluster algebra is of finite type and the structures we describe quantize those found by Scott for the classical situation.

Grabowski, Jan E

2009-01-01

406

Complete 1H and 13C NMR structural assignments for a group of four goyazensolide-type furanoheliangolides  

International Nuclear Information System (INIS)

Four goyazensolide-type sesquiterpene lactones - lychnofolide, centratherin, goyazensolide and goyazensolide acetate - were thoroughly studied by NMR experimental techniques. 1H NMR, 13C NMR {1H}, COSY, HMQC, HMBC, J-res. and NOE experiments were performed to provide the needed structural information. Complete and unequivocal assignment, including the determination of all multiplicities, was obtained for each structure and the data collections are presented in tables (author)

407

Complete {sup 1}H and {sup 13}C NMR structural assignments for a group of four goyazensolide-type furanoheliangolides  

Energy Technology Data Exchange (ETDEWEB)

Four goyazensolide-type sesquiterpene lactones - lychnofolide, centratherin, goyazensolide and goyazensolide acetate - were thoroughly studied by NMR experimental techniques. {sup 1}H NMR, {sup 13}C NMR {l_brace}{sup 1}H{r_brace}, COSY, HMQC, HMBC, J-res. and NOE experiments were performed to provide the needed structural information. Complete and unequivocal assignment, including the determination of all multiplicities, was obtained for each structure and the data collections are presented in tables (author)

Soares, Ana Carolina Ferreira; Silva, Aline Nazare; Matos, Priscilla Mendonca; Silva, Eder Henrique da; Heleno, Vladimir Constantino Gomes [Universidade de Franca, Franca, SP (Brazil). Nucleo de Pesquisas em Ciencias Exatas e Tecnologicas; Lopes, Norberto Peporine; Lopes, Joao Luis Callegari [Universidade de Sao Paulo (FCFRP/USP), Ribeirao Preto, SP (Brazil). Fac. de Ciencias Farmaceuticas de Ribeirao Preto. Dept. de Quimica e Fisica; Sass, Daiane Cristina, E-mail: vheleno_05@yahoo.com.br [Universidade de Sao Paulo (FFCLRP/USP), Ribeirao Preto, SP (Brazil). Fac. de Filosofia, Ciencias e Letras de Ribeirao Preto. Dept. de Quimica

2012-07-01

408

A zig-zag domain-wall structure of the incommensurate phase in A 2BX4-type crystals  

OpenAIRE

Within Landau theory of phase transitions in A2BX4 — type crystals we introduce in the free energy a new third-order Umklapp term. In the incommensurate phase this term can induce a new phase transition connected with a rotation of the wave vector of modulation away from the a* direction. The electrostatic energy in these improper ferroelectrics could induce in fact a zig-zag domain-wall structure, i.e. a structure also modulated along b*.

Dvorak, V.; Lajzerowicz, J.

1986-01-01

409

Low temperature specific heat of the superconducting zirconium-transition metal compounds of the CuAl2 type structure  

International Nuclear Information System (INIS)

In this paper we discuss the superconductivity of the TMZr2 compounds (TM = transition metal) determined by the specific heat measurements. The only AB2 alloys where A=TM and B=Zr are : FeZr2, CoZr2, RhZr2, IrZr2, NiZr2, PdZr2, PtZr2. They all have the C16 structure (CuAl2 type) except for PdZr2 (MoSi2 type) and PtZr2 (Mn5Si3 type). (orig./TW)

410

Crystal structure of activin receptor type IIB kinase domain from human at 2.0 Angstrom resolution.  

Science.gov (United States)

Activin receptor type IIB (ActRIIB), a type II TGF-beta serine/threonine kinase receptor, is integral to the activin and myostatin signaling pathway. Ligands such as activin and myostatin bind to activin type II receptors (ActRIIA, ActRIIB), and the GS domains of type I receptors are phosphorylated by type II receptors. Myostatin, a negative regulator of skeletal muscle growth, is regarded as a potential therapeutic target and binds to ActRIIB effectively, and to a lesser extent, to ActRIIA. The high-resolution structure of human ActRIIB kinase domain in complex with adenine establishes the conserved bilobal architecture consistent with all other catalytic kinase domains. The crystal structure reveals that the adenine has a considerably different orientation from that of the adenine moiety of ATP observed in other kinase structures due to the lack of an interaction by ribose-phosphate moiety and the presence of tautomers with two different protonation states at the N9 nitrogen. Although the Lys217-Glu230 salt bridge is absent, the unphosphorylated activation loop of ActRIIB adopts a conformation similar to that of the fully active form. Unlike the type I TGF-beta receptor, where a partially conserved Ser280 is a gatekeeper residue, the AcRIIB structure possesses Thr265 with a back pocket supported by Phe247. Taken together, these structural features provide a molecular basis for understanding the coupled activity and recognition specificity for human ActRIIB kinase domain and for the rational design of selective inhibitors. PMID:17893364

Han, Seungil; Loulakis, Pat; Griffor, Matt; Xie, Zhi

2007-10-01

411

Circadian time structure of endocrine and biochemical parameters in adult onset (type II) diabetic patients.  

Science.gov (United States)

Forty-one endocrine and biochemical serum parameters were studied over a 24-hour span with 6 samples at 4-hour intervals in 20 non-insulin dependent (Type II) diabetics and in 20 non-diabetic subjects matched for sex, age, height and weight. Circadian rhythms were verified by cosinor analysis. Group-synchronized circadian rhythms were detected in diabetic and non-diabetic subjects with no statistically significant difference in any of the rhythm parameters (rhythm adjusted mean, amplitude and acrophase) in: Aldosterone, cortisol, insulin, 17-OH progesterone, prolactin, testosterone, TSH, and in serum albumin, creatine phosphokinase (CPK), serum iron, inorganic phosphate and total protein. Statistically significant (p less than .05) circadian rhythms in both groups with a difference in some parameters between the diabetic and the non-diabetic subjects, which were verified by the Bingham Test (p less than .05) were found with a difference in the mesor in cholesterol, glucose, urea nitrogen (BUN), in the amplitude in C-peptide and in the acrophase in triglycerides, globulin and reverse T3 (rT3). Statistically significant circadian rhythms were detected as a group phenomenon for the diabetics only in progesterone, free and total T4, chloride, calcium, bilirubin and LDH and in the non-diabetic subjects only in ACTH, LH, total T3, alkaline phosphatase, uric acid and potassium. In the remainder of the functions studied, a circadian rhythm was detectable with statistical significance by cosinor analysis as a group phenomenon neither in the diabetics nor in the matched non-diabetic controls (DHEA-S, estradiol, FSH, GH, glucagon, free T3, sodium, GOT and gamma GT). In the absence of a detectable circadian rhythm as group phenomenon, the circadian mean was different between the diabetics and the non-diabetic subjects in sodium, chloride and calcium which were higher in the diabetic patients and serum LDH which was lower. In a comparison of endocrine determinations in the two groups, the circadian mean or mesor in T3 was lower in the diabetics and ACTH higher, without corresponding changes in TSH or in corticosteroids. The circadian time structure of Type II diabetic patients thus seems to be very similar to that seen in non-diabetic subjects of the same sex, age, weight and height. The minor differences found in some rhythm parameters will have to be confirmed or excluded in larger numbers of subjects. The higher circadian mean ACTH concentrations without change in steroid rhythm parameters observed in this group is interesting but will also require confirmation.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:6523019

Nicolau, G Y; Haus, E; Lakatua, D; Bogdan, C; Petrescu, E; Robu, E; Sackett-Lundeen, L; Swoyer, J; Adderley, J

1984-01-01

412

High-pressure synthesis, crystal structure and magnetic property of ilmenite-type FeGeO{sub 3}  

Energy Technology Data Exchange (ETDEWEB)

We synthesized well-crystallized ilmenite-type FeGeO{sub 3} to investigate its structural and magnetic properties. Ilmenite-type FeGeO{sub 3} were synthesized by high-pressure synthesis technique using a Kawai-type multi-anvil apparatus. Their structural and magnetic properties were examined by XRD analysis with Rietveld refinement, transmission electron microscopy, Moessbauer spectroscopy and SQUID-magnetization measurements. The subsequent annealing after the high-pressure synthesis was effective to improve the crystallinity of the ilmenite-type FeGeO{sub 3}. The primary particle size of ilmenite-type FeGeO{sub 3} was {approx}15 nm. Some particles seemed to be covered with non- or poorly crystalline phase even after the annealing, and others showed a lamellar microstructure parallel to the (0 0 1) plane. Theilmenite-type FeGeO{sub 3} showed typical antiferromagnetic behavior with the Neel temperature of 79 K. - Graphical abstract: Crystal structure, transmission electron micrograph and temperature dependent susceptibility of ilmenite-type FeGeO{sub 3}. Highlights: Black-Right-Pointing-Pointer Ilmenite-type FeGeO{sub 3}, a novel polymorphism of FeGeO{sub 3} was successfully synthesized. Black-Right-Pointing-Pointer It was synthesized by using high pressure technique at 23.5 GPa at 500 Degree-Sign C. Black-Right-Pointing-Pointer Subsequent annealing in vacuum was effective to improve the crystallinity. Black-Right-Pointing-Pointer Its primary particle size was {approx}15 nm, and some grains had lamellar microstructure. Black-Right-Pointing-Pointer It showed typical antiferromagnetic behavior with the Neel temperature of 79 K.

Nakatsuka, Daisuke, E-mail: dns421305@s.okayama-u.ac.jp [Graduate School of Natural Science and Technology, Okayama University, Tsushiuma-naka 3-1-1, Okayama 700-8530 (Japan); Yoshino, Takashi [Institute for Study of the Earth' s Interior, Okayama University, Misasa, Tottori 682-0193 (Japan); Kano, Jun; Hashimoto, Hideki; Nakanishi, Makoto; Takada, Jun; Fujii, Tatsuo [Graduate School of Natural Science and Technology, Okayama University, Tsushiuma-naka 3-1-1, Okayama 700-8530 (Japan)

2013-02-15

413

Coder and decoder of fractal signals of comb-type structure  

Directory of Open Access Journals (Sweden)

Full Text Available The article presents a coder and decoder of fractal signals of comb-type structure (FSCS based on microcontrollers (MC. The coder and decoder consist of identical control modules, while their managed modules have different schematic constructions. The control module performs forming or recognition of signals, and also carries out the function of information exchange with a computer. The basic element of the control module is a PIC18F2550 microcontroller from MicroChip. The coder of the system forms fractal signals of a given order according to the information bits coming from the computer. Samples of the calculated values of the amplitudes of elementary rectangular pulses that constitute the structure of fractal pulses are stored in the memory of the microcontroller as a table. Minimum bit capacity of the DAC necessary for the generation of FSCS of fourth order is four bits. The operation algorithm, "wired" into the controller of the program, provides for encoding of the transmitted information by two-bit symbols. Recognition of the start of transmission of each byte in communication channel is performed by the transmission of the timing signal. In a decoder the microcontroller carries out reception and decoding of the received fractal signals which are then transmitted to the computer. The developed algorithm of the program for the microcontroller of the decoder is carried out by determination of order of fractal impulse after the value of sum of amplitudes of elementary impulses, constituents fractal signal. The programs for coder and decoder are written in "C". In the most critical places of the program influencing on the fast-acting of chart “assembler” insertions are done. The blocks of the coder and decoder were connected with a coaxial 10 meters long cable with an impendance of 75 Ohm. The signals generated by the developed coder of FSCS, were studied using a digital oscillograph. On the basis of the obtained spectrums, it is possible to draw a conclusion, that the fractal signals formed by the coder are wideband and can be used in noise-resistant and protected communication systems.

Politanskyi R. L.

2014-08-01

414

Temperature-dependent structural studies of mullite-type Bi2Fe4O9  

International Nuclear Information System (INIS)

We report on the temperature-dependent structural studies on the mullite-type Bi2Fe4O9 compound. The crystal structures were determined using both powder X-ray diffraction and single crystal neutron diffraction. The thermal expansion of the cell parameters from smallest to largest occurred in the order a6 polyhedral volume. At the same temperature the FeO4 tetrahedral distortion starts to increase. The temperature-dependent stereochemically activity of the Bi3+ 6s2 lone electron pair was probed by the absolute value of eccentricity parameter. This parameter shows a significant drop at around 773 K. Additionally, the average crystal size and micro-strain of the powder samples were studied. A healing of intrinsic defects is observed with respect to a decreasing micro-strain followed by crystal growth above about 900 K. The temperature-dependent infrared spectra were described in three distinct zones. Deconvolution of the absorption features between 370 cm?1 and 1000 cm?1 required nine fitted bands, and the decomposed Pine fitted bands, and the decomposed Pseudo-Voigt elements were assigned to Fe–O stretching, Fe–O–Fe bending and O–Fe–O bending vibrations. The shift of the observed modes was described with respect to temperature. An effective linewidth parameter ?corr was determined by autocorrelation analysis between 740 cm?1 and 900 cm?1 for each temperature-dependent spectrum. The break of the slope of ?corr at about 773 K was interpreted as the change of some vibrational modes of the FeO4 tetrahedra. The intrinsic effects observed around 773 K are responsible for extrinsic parameter changes found around 900 K. - Graphical abstract: Temperature-dependent stereochemical activity (eccentricity |?i|) of the Bi3+ 6s2 lone electron pair directing in the non-bonded region of the Bi–O coordination in the Bi2Fe4O9 iron framework (given as polyhedra). Highlights: ? Complex expansion–contraction mechanism explains anisotropic thermal expansion. ? Bi 6s2 lone electron pair sphericity influences analyses by FTIR autocorrelation. ? Intrinsic effects at 773 K are responsible for extrinsic parameter changes at 900 K.

415

Structural and functional properties of ryanodine receptor type 3 in zebrafish tail muscle.  

Science.gov (United States)

The ryanodine receptor (RyR)1 isoform of the sarcoplasmic reticulum (SR) Ca(2+) release channel is an essential component of all skeletal muscle fibers. RyR1s are detectable as "junctional feet" (JF) in the gap between the SR and the plasmalemma or T-tubules, and they are required for excitation-contraction (EC) coupling and differentiation. A second isoform, RyR3, does not sustain EC coupling and differentiation in the absence of RyR1 and is expressed at highly variable levels. Anatomically, RyR3 expression correlates with the presence of parajunctional feet (PJF), which are located on the sides of the SR junctional cisternae in an arrangement found only in fibers expressing RyR3. In frog muscle fibers, the presence of RyR3 and PJF correlates with the occurrence of Ca(2+) sparks, which are elementary SR Ca(2+) release events of the EC coupling machinery. Here, we explored the structural and functional roles of RyR3 by injecting zebrafish (Danio rerio) one-cell stage embryos with a morpholino designed to specifically silence RyR3 expression. In zebrafish larvae at 72 h postfertilization, fast-twitch fibers from wild-type (WT) tail muscles had abundant PJF. Silencing resulted in a drop of the PJF/JF ratio, from 0.79 in WT fibers to 0.03 in the morphants. The frequency with which Ca(2+) sparks were detected dropped correspondingly, from 0.083 to 0.001 sarcomere(-1) s(-1). The few Ca(2+) sparks detected in morphant fibers were smaller in amplitude, duration, and spatial extent compared with those in WT fibers. Despite the almost complete disappearance of PJF and Ca(2+) sparks in morphant fibers, these fibers looked structurally normal and the swimming behavior of the larvae was not affected. This paper provides important evidence that RyR3 is the main constituent of the PJF and is the main contributor to the SR Ca(2+) flux underlying Ca(2+) sparks detected in fully differentiated frog and fish fibers. PMID:25667412

Perni, Stefano; Marsden, Kurt C; Escobar, Matias; Hollingworth, Stephen; Baylor, Stephen M; Franzini-Armstrong, Clara

2015-03-01

416

Synthesis and molecular structure of thiosemicarbazidediacetate(monoaqua)oxovanadium (4) monohydrate. New type of geometric isomerism of coordination compounds  

International Nuclear Information System (INIS)

Structure of for the first time synthesized oxovanadium (4) complex with thiosemicarbazidediacetate acid (H2L) is described. It is shown that the structure consists of two crystallographically - and crystallochemically-different [VOLxH2O] complexes. Vanadium atom in both complexes has distorted octahedrial surroundings. In the structure considered the simultaneous presence of two geometric isomers of an carlier unknown type, which formation is possible due to different relative position of organic ligand branches, which are unequal in donor atoms is realized

417

Comparison of the spatial and temporal structure of type-I ELMs  

International Nuclear Information System (INIS)

A comparison of the spatial and temporal evolution of the filamentary structures observed during type I ELMs is presented from a variety of diagnostics and machines. There is evidence that these filaments can be detected inside the LCFS prior to ELMs. The filaments do not have a circular cross section instead they are elongated in the perpendicular (poloidal) direction and this size appears to increase linearly with the minor radius of the machine. The filaments start off rotating toroidally/poloidally with velocities close to that of the pedestal. This velocity then decreases as the filaments propagate radially. By comparing the results from all measurements and from comparison with models it is most likely that the filaments have at least their initial radial velocity when they are far out into the SOL and before they have interacted with the nearest limiter surface. There is a general consensus that the dominant loss mechanism in the separated filaments is through parallel transport and that the transport to the wall is through the radial propagation of these filaments. Measurements of the filament energy content show that each filament contains up to 2.5% of the energy released by the ELM at the time it separates from the LCFS, assuming Ti = Te. The parallel flux e-folding length measured on DIII-D, AUG and MAST has a weaker scaling with normalised ELM size than appears to be necessary to explain the deficit in the ELM energy arriving in the divertor on JET, assumrgy arriving in the divertor on JET, assuming a purely exponential decay of the filament energy with time

418

Thermoelectric material including a multiple transition metal-doped type I clathrate crystal structure  

Science.gov (United States)

A thermoelectric material includes a multiple transition metal-doped type I clathrate crystal structure having the formula A.sub.8TM.sub.y.sub.1.sup.1TM.sub.y.sub.2.sup.2 . . . TM.sub.y.sub.n.sup.nM.sub.zX.sub.46-y.sub.1.sub.-y.sub.2.sub.- . . . -y.sub.n.sub.-z. In the formula, A is selected from the group consisting of barium, strontium, and europium; X is selected from the group consisting of silicon, germanium, and tin; M is selected from the group consisting of aluminum, gallium, and indium; TM.sup.1, TM.sup.2, and TM.sup.n are independently selected from the group consisting of 3d, 4d, and 5d transition metals; and y.sub.1, y.sub.2, y.sub.n and Z are actual compositions of TM.sup.1, TM.sup.2, TM.sup.n, and M, respectively. The actual compositions are based upon nominal compositions derived from the following equation: z=8q.sub.A-|.DELTA.q.sub.1|y.sub.1-|.DELTA.q.sub.2|y.sub.2- . . . -|.DELTA.q.sub.n|y.sub.n, wherein q.sub.A is a charge state of A, and wherein .DELTA.q.sub.1, .DELTA.q.sub.2, .DELTA.q.sub.n are, respectively, the nominal charge state of the first, second, and n-th TM.

Yang, Jihui (Lakeshore, CA); Shi, Xun (Troy, MI); Bai, Shengqiang (Shanghai, CN); Zhang, Wenqing (Shanghai, CN); Chen, Lidong (Shanghai, CN); Yang, Jiong (Shanghai, CN)

2012-01-17

419

Estimating structural integrity of type 304 stainless steel plates and pipes containing small defects  

International Nuclear Information System (INIS)

In recent years there has been considerable demand for accurate assessment of the influence of defects on structural component integrity. Analyses used must account for the effect of large plastic deformation of low-strength ductile materials. A number of models have been developed for the analysis of reactor coolant piping as well as less ductile plate and piping, but these models have not been verified for the full spectrum of potential materials and configurations encountered in reactor components. This paper presents preliminary test program results and some evaluation of these models, specifically the flow stress approach and the two-paramenter fracture criterion (TPFC). The tests were conducted with annealed Type 304 stainless steel flat tensile specimens containing triangular, rectangular, or part-circular surface flaws, and pressurized pipe specimens with internal or external triangular surface defects. The flow stress approach was found to be unsatisfactory as indicated by the conservative estimate for the pipe specimen and by the large amount of scatter for the flat plate specimens. The TPFC approach was used in conjunction with the initial defect size and the loads required for crack initiation as well as the load at penetration. There is a tendency for the TPFC to overpredict crack initiation stress intensity for small cracks and underpredict initiation stress intensity for large cracks, but there appears to be no effect of the defect configuration. The TPeffect of the defect configuration. The TPFC predicts penetration stress intensity more closely over the full range of crack size and in this case there is a definite dependence on defect configuration with the rectangular flaws having lower stress intensity than the others. Even though some modification may be necessary, the TPFC approach may have broad applicability since the data for the pipe specimens are in reasonable agreement with the data for the flat plate specimens. (orig.)

420

Lead-strontium borate halides with hilgardite-type structure and their SHG properties  

International Nuclear Information System (INIS)

Lead-containing members of the hilgardite family of borate halides, M2B5O9X (M=Ca, Sr, Ba, Pb; X=Cl, Br) exhibit an abnormally large nonlinear optical response. In order to establish any underlying crystal-chemical rationale for this we have carried out detailed crystallographic characterisations of the representative members of this series, Sr2B5O9Cl and Pb2B5O9Cl, using powder neutron diffraction. Both adopt the orthorhombic hilgardite structure type, in space group Pnn2. The full solid solution range Pb2-xSrxB5O9Cl has also been prepared, and studied by X-ray Rietveld and second harmonic generation (SHG) measurements. The SHG response shows a linear decrease with increasing x, whereas the unit cell shows an increasing orthorhombic distortion. However, the crystallographic results suggest no significant or systematic changes in the nature of the borate sublattice between Sr2B5O9Cl and Pb2B5O9Cl. We conclude that the enhanced SHG response in Pb-containing hilgardites is due predominantly to the presence of the polarizable nature of Pb2+, in particular the presence of a stereochemically active lone pair. - Graphical abstract: Sr2B5O9Cl, Pb2B5O9Cl and the solid solution range Pb2-x2-xSrxB5O9Cl has been prepared, and studied by powder neutron and X-ray diffraction and SHG measurements